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.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
******************
Variables Glossary
******************
This chapter lists common variables used in the OpenEmbedded build
system and gives an overview of their function and contents.
:term:`A <ABIEXTENSION>` :term:`B` :term:`C <CACHE>`
:term:`D` :term:`E <EFI_PROVIDER>` :term:`F <FEATURE_PACKAGES>`
:term:`G <GCCPIE>` :term:`H <HOMEPAGE>` :term:`I <ICECC_DISABLED>`
:term:`K <KARCH>` :term:`L <LABELS>` :term:`M <MACHINE>`
:term:`N <NATIVELSBSTRING>` :term:`O <OBJCOPY>` :term:`P`
:term:`R <RANLIB>` :term:`S` :term:`T`
:term:`U <UBOOT_CONFIG>` :term:`V <VOLATILE_LOG_DIR>`
:term:`W <WARN_QA>` :term:`X <XSERVER>`
.. glossary::
:sorted:
:term:`ABIEXTENSION`
Extension to the Application Binary Interface (ABI) field of the GNU
canonical architecture name (e.g. "eabi").
ABI extensions are set in the machine include files. For example, the
``meta/conf/machine/include/arm/arch-arm.inc`` file sets the
following extension::
ABIEXTENSION = "eabi"
:term:`ALLOW_EMPTY`
Specifies whether to produce an output package even if it is empty.
By default, BitBake does not produce empty packages. This default
behavior can cause issues when there is an
:term:`RDEPENDS` or some other hard runtime
requirement on the existence of the package.
Like all package-controlling variables, you must always use them in
conjunction with a package name override, as in::
ALLOW_EMPTY:${PN} = "1"
ALLOW_EMPTY:${PN}-dev = "1"
ALLOW_EMPTY:${PN}-staticdev = "1"
:term:`ALTERNATIVE`
Lists commands in a package that need an alternative binary naming
scheme. Sometimes the same command is provided in multiple packages.
When this occurs, the OpenEmbedded build system needs to use the
alternatives system to create a different binary naming scheme so the
commands can co-exist.
To use the variable, list out the package's commands that are also
provided by another package. For example, if the ``busybox`` package
has four such commands, you identify them as follows::
ALTERNATIVE:busybox = "sh sed test bracket"
For more information on the alternatives system, see the
":ref:`ref-classes-update-alternatives`"
section.
:term:`ALTERNATIVE_LINK_NAME`
Used by the alternatives system to map duplicated commands to actual
locations. For example, if the ``bracket`` command provided by the
``busybox`` package is duplicated through another package, you must
use the :term:`ALTERNATIVE_LINK_NAME` variable to specify the actual
location::
ALTERNATIVE_LINK_NAME[bracket] = "/usr/bin/["
In this example, the binary for the ``bracket`` command (i.e. ``[``)
from the ``busybox`` package resides in ``/usr/bin/``.
.. note::
If :term:`ALTERNATIVE_LINK_NAME` is not defined, it defaults to ``${bindir}/name``.
For more information on the alternatives system, see the
":ref:`ref-classes-update-alternatives`"
section.
:term:`ALTERNATIVE_PRIORITY`
Used by the alternatives system to create default priorities for
duplicated commands. You can use the variable to create a single
default regardless of the command name or package, a default for
specific duplicated commands regardless of the package, or a default
for specific commands tied to particular packages. Here are the
available syntax forms::
ALTERNATIVE_PRIORITY = "priority"
ALTERNATIVE_PRIORITY[name] = "priority"
ALTERNATIVE_PRIORITY_pkg[name] = "priority"
For more information on the alternatives system, see the
":ref:`ref-classes-update-alternatives`"
section.
:term:`ALTERNATIVE_TARGET`
Used by the alternatives system to create default link locations for
duplicated commands. You can use the variable to create a single
default location for all duplicated commands regardless of the
command name or package, a default for specific duplicated commands
regardless of the package, or a default for specific commands tied to
particular packages. Here are the available syntax forms::
ALTERNATIVE_TARGET = "target"
ALTERNATIVE_TARGET[name] = "target"
ALTERNATIVE_TARGET_pkg[name] = "target"
.. note::
If :term:`ALTERNATIVE_TARGET` is not defined, it inherits the value
from the :term:`ALTERNATIVE_LINK_NAME` variable.
If :term:`ALTERNATIVE_LINK_NAME` and :term:`ALTERNATIVE_TARGET` are the
same, the target for :term:`ALTERNATIVE_TARGET` has "``.{BPN}``"
appended to it.
Finally, if the file referenced has not been renamed, the
alternatives system will rename it to avoid the need to rename
alternative files in the :ref:`ref-tasks-install`
task while retaining support for the command if necessary.
For more information on the alternatives system, see the
":ref:`ref-classes-update-alternatives`" section.
:term:`ANY_OF_DISTRO_FEATURES`
When inheriting the :ref:`ref-classes-features_check`
class, this variable identifies a list of distribution features where
at least one must be enabled in the current configuration in order
for the OpenEmbedded build system to build the recipe. In other words,
if none of the features listed in :term:`ANY_OF_DISTRO_FEATURES`
appear in :term:`DISTRO_FEATURES` within the current configuration, then
the recipe will be skipped, and if the build system attempts to build
the recipe then an error will be triggered.
:term:`APPEND`
An override list of append strings for each target specified with
:term:`LABELS`.
See the :ref:`ref-classes-grub-efi` class for more
information on how this variable is used.
:term:`AR`
The minimal command and arguments used to run ``ar``.
:term:`ARCHIVER_MODE`
When used with the :ref:`ref-classes-archiver` class,
determines the type of information used to create a released archive.
You can use this variable to create archives of patched source,
original source, configured source, and so forth by employing the
following variable flags (varflags)::
ARCHIVER_MODE[src] = "original" # Uses original (unpacked) source files.
ARCHIVER_MODE[src] = "patched" # Uses patched source files. This is the default.
ARCHIVER_MODE[src] = "configured" # Uses configured source files.
ARCHIVER_MODE[diff] = "1" # Uses patches between do_unpack and do_patch.
ARCHIVER_MODE[diff-exclude] ?= "file file ..." # Lists files and directories to exclude from diff.
ARCHIVER_MODE[dumpdata] = "1" # Uses environment data.
ARCHIVER_MODE[recipe] = "1" # Uses recipe and include files.
ARCHIVER_MODE[srpm] = "1" # Uses RPM package files.
For information on how the variable works, see the
``meta/classes/archiver.bbclass`` file in the :term:`Source Directory`.
:term:`AS`
Minimal command and arguments needed to run the assembler.
:term:`ASSUME_PROVIDED`
Lists recipe names (:term:`PN` values) BitBake does not
attempt to build. Instead, BitBake assumes these recipes have already
been built.
In OpenEmbedded-Core, :term:`ASSUME_PROVIDED` mostly specifies native
tools that should not be built. An example is ``git-native``, which
when specified, allows for the Git binary from the host to be used
rather than building ``git-native``.
:term:`ASSUME_SHLIBS`
Provides additional ``shlibs`` provider mapping information, which
adds to or overwrites the information provided automatically by the
system. Separate multiple entries using spaces.
As an example, use the following form to add an ``shlib`` provider of
shlibname in packagename with the optional version::
shlibname:packagename[_version]
Here is an example that adds a shared library named ``libEGL.so.1``
as being provided by the ``libegl-implementation`` package::
ASSUME_SHLIBS = "libEGL.so.1:libegl-implementation"
:term:`AUTHOR`
The email address used to contact the original author or authors in
order to send patches and forward bugs.
:term:`AUTO_LIBNAME_PKGS`
When the :ref:`ref-classes-debian` class is inherited,
which is the default behavior, :term:`AUTO_LIBNAME_PKGS` specifies which
packages should be checked for libraries and renamed according to
Debian library package naming.
The default value is "${PACKAGES}", which causes the
:ref:`ref-classes-debian` class to act on all packages that are
explicitly generated by the recipe.
:term:`AUTOREV`
When :term:`SRCREV` is set to the value of this variable, it specifies to
use the latest source revision in the repository. Here is an example::
SRCREV = "${AUTOREV}"
If you use the previous statement to retrieve the latest version of
software, you need to be sure :term:`PV` contains
``${``\ :term:`SRCPV`\ ``}``. For example, suppose you have a kernel
recipe that inherits the :ref:`ref-classes-kernel` class and you
use the previous statement. In this example, ``${SRCPV}`` does not
automatically get into :term:`PV`. Consequently, you need to change
:term:`PV` in your recipe so that it does contain ``${SRCPV}``.
For more information see the
":ref:`dev-manual/packages:automatically incrementing a package version number`"
section in the Yocto Project Development Tasks Manual.
:term:`AUTO_SYSLINUXMENU`
Enables creating an automatic menu for the syslinux bootloader. You
must set this variable in your recipe. The
:ref:`ref-classes-syslinux` class checks this variable.
:term:`AVAILTUNES`
The list of defined CPU and Application Binary Interface (ABI)
tunings (i.e. "tunes") available for use by the OpenEmbedded build
system.
The list simply presents the tunes that are available. Not all tunes
may be compatible with a particular machine configuration, or with
each other in a
:ref:`Multilib <dev-manual/libraries:combining multiple versions of library files into one image>`
configuration.
To add a tune to the list, be sure to append it with spaces using the
"+=" BitBake operator. Do not simply replace the list by using the
"=" operator. See the
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:basic syntax`" section in the BitBake
User Manual for more information.
:term:`AZ_SAS`
Azure Storage Shared Access Signature, when using the
:ref:`Azure Storage fetcher (az://) <bitbake:bitbake-user-manual/bitbake-user-manual-fetching:fetchers>`
This variable can be defined to be used by the fetcher to authenticate
and gain access to non-public artifacts::
AZ_SAS = ""se=2021-01-01&sp=r&sv=2018-11-09&sr=c&skoid=<skoid>&sig=<signature>""
For more information see Microsoft's Azure Storage documentation at
https://docs.microsoft.com/en-us/azure/storage/common/storage-sas-overview
:term:`B`
The directory within the :term:`Build Directory` in which the
OpenEmbedded build system places generated objects during a recipe's
build process. By default, this directory is the same as the
:term:`S` directory, which is defined as::
S = "${WORKDIR}/${BP}"
You can separate the (:term:`S`) directory and the directory pointed to
by the :term:`B` variable. Most Autotools-based recipes support
separating these directories. The build system defaults to using
separate directories for ``gcc`` and some kernel recipes.
:term:`BAD_RECOMMENDATIONS`
Lists "recommended-only" packages to not install. Recommended-only
packages are packages installed only through the
:term:`RRECOMMENDS` variable. You can prevent any
of these "recommended" packages from being installed by listing them
with the :term:`BAD_RECOMMENDATIONS` variable::
BAD_RECOMMENDATIONS = "package_name package_name package_name ..."
You can set this variable globally in your ``local.conf`` file or you
can attach it to a specific image recipe by using the recipe name
override::
BAD_RECOMMENDATIONS:pn-target_image = "package_name"
It is important to realize that if you choose to not install packages
using this variable and some other packages are dependent on them
(i.e. listed in a recipe's :term:`RDEPENDS`
variable), the OpenEmbedded build system ignores your request and
will install the packages to avoid dependency errors.
This variable is supported only when using the IPK and RPM
packaging backends. DEB is not supported.
See the :term:`NO_RECOMMENDATIONS` and the
:term:`PACKAGE_EXCLUDE` variables for related
information.
:term:`BASE_LIB`
The library directory name for the CPU or Application Binary
Interface (ABI) tune. The :term:`BASE_LIB` applies only in the Multilib
context. See the ":ref:`dev-manual/libraries:combining multiple versions of library files into one image`"
section in the Yocto Project Development Tasks Manual for information
on Multilib.
The :term:`BASE_LIB` variable is defined in the machine include files in
the :term:`Source Directory`. If Multilib is not
being used, the value defaults to "lib".
:term:`BASE_WORKDIR`
Points to the base of the work directory for all recipes. The default
value is "${TMPDIR}/work".
:term:`BB_ALLOWED_NETWORKS`
Specifies a space-delimited list of hosts that the fetcher is allowed
to use to obtain the required source code. Following are
considerations surrounding this variable:
- This host list is only used if :term:`BB_NO_NETWORK` is either not set
or set to "0".
- There is limited support for wildcard matching against the beginning of
host names. For example, the following setting matches
``git.gnu.org``, ``ftp.gnu.org``, and ``foo.git.gnu.org``::
BB_ALLOWED_NETWORKS = "*.gnu.org"
.. note::
The use of the "``*``" character only works at the beginning of
a host name and it must be isolated from the remainder of the
host name. You cannot use the wildcard character in any other
location of the name or combined with the front part of the
name.
For example, ``*.foo.bar`` is supported, while ``*aa.foo.bar``
is not.
- Mirrors not in the host list are skipped and logged in debug.
- Attempts to access networks not in the host list cause a failure.
Using :term:`BB_ALLOWED_NETWORKS` in conjunction with
:term:`PREMIRRORS` is very useful. Adding the host
you want to use to :term:`PREMIRRORS` results in the source code being
fetched from an allowed location and avoids raising an error when a
host that is not allowed is in a :term:`SRC_URI`
statement. This is because the fetcher does not attempt to use the
host listed in :term:`SRC_URI` after a successful fetch from the
:term:`PREMIRRORS` occurs.
:term:`BB_BASEHASH_IGNORE_VARS`
See :term:`bitbake:BB_BASEHASH_IGNORE_VARS` in the BitBake manual.
:term:`BB_CHECK_SSL_CERTS`
See :term:`bitbake:BB_CHECK_SSL_CERTS` in the BitBake manual.
:term:`BB_CONSOLELOG`
See :term:`bitbake:BB_CONSOLELOG` in the BitBake manual.
:term:`BB_CURRENTTASK`
See :term:`bitbake:BB_CURRENTTASK` in the BitBake manual.
:term:`BB_DANGLINGAPPENDS_WARNONLY`
Defines how BitBake handles situations where an append file
(``.bbappend``) has no corresponding recipe file (``.bb``). This
condition often occurs when layers get out of sync (e.g. ``oe-core``
bumps a recipe version and the old recipe no longer exists and the
other layer has not been updated to the new version of the recipe
yet).
The default fatal behavior is safest because it is the sane reaction
given something is out of sync. It is important to realize when your
changes are no longer being applied.
You can change the default behavior by setting this variable to "1",
"yes", or "true" in your ``local.conf`` file, which is located in the
:term:`Build Directory`: Here is an example::
BB_DANGLINGAPPENDS_WARNONLY = "1"
:term:`BB_DEFAULT_TASK`
See :term:`bitbake:BB_DEFAULT_TASK` in the BitBake manual.
:term:`BB_DEFAULT_UMASK`
See :term:`bitbake:BB_DEFAULT_UMASK` in the BitBake manual.
:term:`BB_DISKMON_DIRS`
Monitors disk space and available inodes during the build and allows
you to control the build based on these parameters.
Disk space monitoring is disabled by default. To enable monitoring,
add the :term:`BB_DISKMON_DIRS` variable to your ``conf/local.conf`` file
found in the :term:`Build Directory`. Use the
following form:
.. code-block:: none
BB_DISKMON_DIRS = "action,dir,threshold [...]"
where:
action is:
ABORT: Immediately stop the build when
a threshold is broken.
STOPTASKS: Stop the build after the currently
executing tasks have finished when
a threshold is broken.
WARN: Issue a warning but continue the
build when a threshold is broken.
Subsequent warnings are issued as
defined by the BB_DISKMON_WARNINTERVAL
variable, which must be defined in
the conf/local.conf file.
dir is:
Any directory you choose. You can specify one or
more directories to monitor by separating the
groupings with a space. If two directories are
on the same device, only the first directory
is monitored.
threshold is:
Either the minimum available disk space,
the minimum number of free inodes, or
both. You must specify at least one. To
omit one or the other, simply omit the value.
Specify the threshold using G, M, K for Gbytes,
Mbytes, and Kbytes, respectively. If you do
not specify G, M, or K, Kbytes is assumed by
default. Do not use GB, MB, or KB.
Here are some examples::
BB_DISKMON_DIRS = "ABORT,${TMPDIR},1G,100K WARN,${SSTATE_DIR},1G,100K"
BB_DISKMON_DIRS = "STOPTASKS,${TMPDIR},1G"
BB_DISKMON_DIRS = "ABORT,${TMPDIR},,100K"
The first example works only if you also provide the
:term:`BB_DISKMON_WARNINTERVAL`
variable in the ``conf/local.conf``. This example causes the build
system to immediately stop when either the disk space in
``${TMPDIR}`` drops below 1 Gbyte or the available free inodes drops
below 100 Kbytes. Because two directories are provided with the
variable, the build system also issue a warning when the disk space
in the ``${SSTATE_DIR}`` directory drops below 1 Gbyte or the number
of free inodes drops below 100 Kbytes. Subsequent warnings are issued
during intervals as defined by the :term:`BB_DISKMON_WARNINTERVAL`
variable.
The second example stops the build after all currently executing
tasks complete when the minimum disk space in the ``${TMPDIR}``
directory drops below 1 Gbyte. No disk monitoring occurs for the free
inodes in this case.
The final example immediately stops the build when the number of
free inodes in the ``${TMPDIR}`` directory drops below 100 Kbytes. No
disk space monitoring for the directory itself occurs in this case.
:term:`BB_DISKMON_WARNINTERVAL`
Defines the disk space and free inode warning intervals. To set these
intervals, define the variable in your ``conf/local.conf`` file in
the :term:`Build Directory`.
If you are going to use the :term:`BB_DISKMON_WARNINTERVAL` variable, you
must also use the :term:`BB_DISKMON_DIRS`
variable and define its action as "WARN". During the build,
subsequent warnings are issued each time disk space or number of free
inodes further reduces by the respective interval.
If you do not provide a :term:`BB_DISKMON_WARNINTERVAL` variable and you
do use :term:`BB_DISKMON_DIRS` with the "WARN" action, the disk
monitoring interval defaults to the following::
BB_DISKMON_WARNINTERVAL = "50M,5K"
When specifying the variable in your configuration file, use the
following form:
.. code-block:: none
BB_DISKMON_WARNINTERVAL = "disk_space_interval,disk_inode_interval"
where:
disk_space_interval is:
An interval of memory expressed in either
G, M, or K for Gbytes, Mbytes, or Kbytes,
respectively. You cannot use GB, MB, or KB.
disk_inode_interval is:
An interval of free inodes expressed in either
G, M, or K for Gbytes, Mbytes, or Kbytes,
respectively. You cannot use GB, MB, or KB.
Here is an example::
BB_DISKMON_DIRS = "WARN,${SSTATE_DIR},1G,100K"
BB_DISKMON_WARNINTERVAL = "50M,5K"
These variables cause the
OpenEmbedded build system to issue subsequent warnings each time the
available disk space further reduces by 50 Mbytes or the number of
free inodes further reduces by 5 Kbytes in the ``${SSTATE_DIR}``
directory. Subsequent warnings based on the interval occur each time
a respective interval is reached beyond the initial warning (i.e. 1
Gbytes and 100 Kbytes).
:term:`BB_ENV_PASSTHROUGH`
See :term:`bitbake:BB_ENV_PASSTHROUGH` in the BitBake manual.
:term:`BB_ENV_PASSTHROUGH_ADDITIONS`
See :term:`bitbake:BB_ENV_PASSTHROUGH_ADDITIONS` in the BitBake manual.
:term:`BB_FETCH_PREMIRRORONLY`
See :term:`bitbake:BB_FETCH_PREMIRRORONLY` in the BitBake manual.
:term:`BB_FILENAME`
See :term:`bitbake:BB_FILENAME` in the BitBake manual.
:term:`BB_GENERATE_MIRROR_TARBALLS`
Causes tarballs of the source control repositories (e.g. Git
repositories), including metadata, to be placed in the
:term:`DL_DIR` directory.
For performance reasons, creating and placing tarballs of these
repositories is not the default action by the OpenEmbedded build
system::
BB_GENERATE_MIRROR_TARBALLS = "1"
Set this variable in your
``local.conf`` file in the :term:`Build Directory`.
Once you have the tarballs containing your source files, you can
clean up your :term:`DL_DIR` directory by deleting any Git or other
source control work directories.
:term:`BB_GENERATE_SHALLOW_TARBALLS`
See :term:`bitbake:BB_GENERATE_SHALLOW_TARBALLS` in the BitBake manual.
:term:`BB_GIT_SHALLOW`
See :term:`bitbake:BB_GIT_SHALLOW` in the BitBake manual.
:term:`BB_GIT_SHALLOW_DEPTH`
See :term:`bitbake:BB_GIT_SHALLOW_DEPTH` in the BitBake manual.
:term:`BB_HASHCHECK_FUNCTION`
See :term:`bitbake:BB_HASHCHECK_FUNCTION` in the BitBake manual.
:term:`BB_HASHCONFIG_IGNORE_VARS`
See :term:`bitbake:BB_HASHCONFIG_IGNORE_VARS` in the BitBake manual.
:term:`BB_HASHSERVE`
See :term:`bitbake:BB_HASHSERVE` in the BitBake manual.
:term:`BB_HASHSERVE_UPSTREAM`
See :term:`bitbake:BB_HASHSERVE_UPSTREAM` in the BitBake manual.
:term:`BB_INVALIDCONF`
See :term:`bitbake:BB_INVALIDCONF` in the BitBake manual.
:term:`BB_LOGCONFIG`
See :term:`bitbake:BB_LOGCONFIG` in the BitBake manual.
:term:`BB_LOGFMT`
See :term:`bitbake:BB_LOGFMT` in the BitBake manual.
:term:`BB_MULTI_PROVIDER_ALLOWED`
See :term:`bitbake:BB_MULTI_PROVIDER_ALLOWED` in the BitBake manual.
:term:`BB_NICE_LEVEL`
See :term:`bitbake:BB_NICE_LEVEL` in the BitBake manual.
:term:`BB_NO_NETWORK`
See :term:`bitbake:BB_NO_NETWORK` in the BitBake manual.
:term:`BB_NUMBER_PARSE_THREADS`
See :term:`bitbake:BB_NUMBER_PARSE_THREADS` in the BitBake manual.
:term:`BB_NUMBER_THREADS`
The maximum number of tasks BitBake should run in parallel at any one
time. The OpenEmbedded build system automatically configures this
variable to be equal to the number of cores on the build system. For
example, a system with a dual core processor that also uses
hyper-threading causes the :term:`BB_NUMBER_THREADS` variable to default
to "4".
For single socket systems (i.e. one CPU), you should not have to
override this variable to gain optimal parallelism during builds.
However, if you have very large systems that employ multiple physical
CPUs, you might want to make sure the :term:`BB_NUMBER_THREADS` variable
is not set higher than "20".
For more information on speeding up builds, see the
":ref:`dev-manual/speeding-up-build:speeding up a build`"
section in the Yocto Project Development Tasks Manual.
On the other hand, if your goal is to limit the amount of system
resources consumed by BitBake tasks, setting :term:`BB_NUMBER_THREADS`
to a number lower than the number of CPU threads in your machine
won't be sufficient. That's because each package will still be built
and installed through a number of parallel jobs specified by the
:term:`PARALLEL_MAKE` variable, which is by default the number of CPU
threads in your system, and is not impacted by the
:term:`BB_NUMBER_THREADS` value.
So, if you set :term:`BB_NUMBER_THREADS` to "1" but don't set
:term:`PARALLEL_MAKE`, most of your system resources will be consumed
anyway.
Therefore, if you intend to reduce the load of your build system by
setting :term:`BB_NUMBER_THREADS` to a relatively low value compared
to the number of CPU threads on your system, you should also set
:term:`PARALLEL_MAKE` to a similarly low value.
An alternative to using :term:`BB_NUMBER_THREADS` to keep the usage
of build system resources under control is to use the smarter
:term:`BB_PRESSURE_MAX_CPU`, :term:`BB_PRESSURE_MAX_IO` or
:term:`BB_PRESSURE_MAX_MEMORY` controls. They will prevent BitBake
from starting new tasks as long as thresholds are exceeded. Anyway,
as with :term:`BB_NUMBER_THREADS`, such controls won't prevent the
tasks already being run from using all CPU threads on the system
if :term:`PARALLEL_MAKE` is not set to a low value.
:term:`BB_ORIGENV`
See :term:`bitbake:BB_ORIGENV` in the BitBake manual.
:term:`BB_PRESERVE_ENV`
See :term:`bitbake:BB_PRESERVE_ENV` in the BitBake manual.
:term:`BB_PRESSURE_MAX_CPU`
See :term:`bitbake:BB_PRESSURE_MAX_CPU` in the BitBake manual.
:term:`BB_PRESSURE_MAX_IO`
See :term:`bitbake:BB_PRESSURE_MAX_IO` in the BitBake manual.
:term:`BB_PRESSURE_MAX_MEMORY`
See :term:`bitbake:BB_PRESSURE_MAX_MEMORY` in the BitBake manual.
:term:`BB_RUNFMT`
See :term:`bitbake:BB_RUNFMT` in the BitBake manual.
:term:`BB_RUNTASK`
See :term:`bitbake:BB_RUNTASK` in the BitBake manual.
:term:`BB_SCHEDULER`
See :term:`bitbake:BB_SCHEDULER` in the BitBake manual.
:term:`BB_SCHEDULERS`
See :term:`bitbake:BB_SCHEDULERS` in the BitBake manual.
:term:`BB_SERVER_TIMEOUT`
Specifies the time (in seconds) after which to unload the BitBake
server due to inactivity. Set :term:`BB_SERVER_TIMEOUT` to determine how
long the BitBake server stays resident between invocations.
For example, the following statement in your ``local.conf`` file
instructs the server to be unloaded after 20 seconds of inactivity::
BB_SERVER_TIMEOUT = "20"
If you want the server to never be unloaded,
set :term:`BB_SERVER_TIMEOUT` to "-1".
:term:`BB_SETSCENE_DEPVALID`
See :term:`bitbake:BB_SETSCENE_DEPVALID` in the BitBake manual.
:term:`BB_SIGNATURE_EXCLUDE_FLAGS`
See :term:`bitbake:BB_SIGNATURE_EXCLUDE_FLAGS` in the BitBake manual.
:term:`BB_SIGNATURE_HANDLER`
See :term:`bitbake:BB_SIGNATURE_HANDLER` in the BitBake manual.
:term:`BB_SRCREV_POLICY`
See :term:`bitbake:BB_SRCREV_POLICY` in the BitBake manual.
:term:`BB_STRICT_CHECKSUM`
See :term:`bitbake:BB_STRICT_CHECKSUM` in the BitBake manual.
:term:`BB_TASK_IONICE_LEVEL`
See :term:`bitbake:BB_TASK_IONICE_LEVEL` in the BitBake manual.
:term:`BB_TASK_NICE_LEVEL`
See :term:`bitbake:BB_TASK_NICE_LEVEL` in the BitBake manual.
:term:`BB_TASKHASH`
See :term:`bitbake:BB_TASKHASH` in the BitBake manual.
:term:`BB_VERBOSE_LOGS`
See :term:`bitbake:BB_VERBOSE_LOGS` in the BitBake manual.
:term:`BB_WORKERCONTEXT`
See :term:`bitbake:BB_WORKERCONTEXT` in the BitBake manual.
:term:`BBCLASSEXTEND`
Allows you to extend a recipe so that it builds variants of the
software. There are common variants for recipes as "natives" like
``quilt-native``, which is a copy of Quilt built to run on the build
system; "crosses" such as ``gcc-cross``, which is a compiler built to
run on the build machine but produces binaries that run on the target
:term:`MACHINE`; ":ref:`ref-classes-nativesdk`", which
targets the SDK machine instead of :term:`MACHINE`; and "mulitlibs" in
the form "``multilib:``\ multilib_name".
To build a different variant of the recipe with a minimal amount of
code, it usually is as simple as adding the following to your recipe::
BBCLASSEXTEND =+ "native nativesdk"
BBCLASSEXTEND =+ "multilib:multilib_name"
.. note::
Internally, the :term:`BBCLASSEXTEND` mechanism generates recipe
variants by rewriting variable values and applying overrides such
as ``:class-native``. For example, to generate a native version of
a recipe, a :term:`DEPENDS` on "foo" is rewritten
to a :term:`DEPENDS` on "foo-native".
Even when using :term:`BBCLASSEXTEND`, the recipe is only parsed once.
Parsing once adds some limitations. For example, it is not
possible to include a different file depending on the variant,
since ``include`` statements are processed when the recipe is
parsed.
:term:`BBDEBUG`
See :term:`bitbake:BBDEBUG` in the BitBake manual.
:term:`BBFILE_COLLECTIONS`
Lists the names of configured layers. These names are used to find
the other ``BBFILE_*`` variables. Typically, each layer will append
its name to this variable in its ``conf/layer.conf`` file.
:term:`BBFILE_PATTERN`
Variable that expands to match files from
:term:`BBFILES` in a particular layer. This variable
is used in the ``conf/layer.conf`` file and must be suffixed with the
name of the specific layer (e.g. ``BBFILE_PATTERN_emenlow``).
:term:`BBFILE_PRIORITY`
Assigns the priority for recipe files in each layer.
This variable is useful in situations where the same recipe appears
in more than one layer. Setting this variable allows you to
prioritize a layer against other layers that contain the same recipe
--- effectively letting you control the precedence for the multiple
layers. The precedence established through this variable stands
regardless of a recipe's version (:term:`PV` variable). For
example, a layer that has a recipe with a higher :term:`PV` value but for
which the :term:`BBFILE_PRIORITY` is set to have a lower precedence still
has a lower precedence.
A larger value for the :term:`BBFILE_PRIORITY` variable results in a
higher precedence. For example, the value 6 has a higher precedence
than the value 5. If not specified, the :term:`BBFILE_PRIORITY` variable
is set based on layer dependencies (see the :term:`LAYERDEPENDS` variable
for more information. The default priority, if unspecified for a
layer with no dependencies, is the lowest defined priority + 1 (or 1
if no priorities are defined).
.. tip::
You can use the command ``bitbake-layers show-layers``
to list all configured layers along with their priorities.
:term:`BBFILES`
A space-separated list of recipe files BitBake uses to build
software.
When specifying recipe files, you can pattern match using Python's
`glob <https://docs.python.org/3/library/glob.html>`__ syntax.
For details on the syntax, see the documentation by following the
previous link.
:term:`BBFILES_DYNAMIC`
Activates content when identified layers are present. You identify
the layers by the collections that the layers define.
Use the :term:`BBFILES_DYNAMIC` variable to avoid ``.bbappend`` files
whose corresponding ``.bb`` file is in a layer that attempts to
modify other layers through ``.bbappend`` but does not want to
introduce a hard dependency on those other layers.
Use the following form for :term:`BBFILES_DYNAMIC`:
``collection_name:filename_pattern``.
The following example identifies two collection names and two
filename patterns::
BBFILES_DYNAMIC += " \
clang-layer:${LAYERDIR}/bbappends/meta-clang/*/*/*.bbappend \
core:${LAYERDIR}/bbappends/openembedded-core/meta/*/*/*.bbappend \
"
This next example shows an error message that occurs because invalid
entries are found, which cause parsing to fail:
.. code-block:: none
ERROR: BBFILES_DYNAMIC entries must be of the form <collection name>:<filename pattern>, not:
/work/my-layer/bbappends/meta-security-isafw/*/*/*.bbappend
/work/my-layer/bbappends/openembedded-core/meta/*/*/*.bbappend
:term:`BBINCLUDED`
See :term:`bitbake:BBINCLUDED` in the BitBake manual.
:term:`BBINCLUDELOGS`
Variable that controls how BitBake displays logs on build failure.
:term:`BBINCLUDELOGS_LINES`
If :term:`BBINCLUDELOGS` is set, specifies the
maximum number of lines from the task log file to print when
reporting a failed task. If you do not set :term:`BBINCLUDELOGS_LINES`,
the entire log is printed.
:term:`BBLAYERS`
Lists the layers to enable during the build. This variable is defined
in the ``bblayers.conf`` configuration file in the :term:`Build Directory`.
Here is an example::
BBLAYERS = " \
/home/scottrif/poky/meta \
/home/scottrif/poky/meta-poky \
/home/scottrif/poky/meta-yocto-bsp \
/home/scottrif/poky/meta-mykernel \
"
This example enables four layers, one of which is a custom,
user-defined layer named ``meta-mykernel``.
:term:`BBLAYERS_FETCH_DIR`
See :term:`bitbake:BBLAYERS_FETCH_DIR` in the BitBake manual.
:term:`BBMASK`
Prevents BitBake from processing recipes and recipe append files.
You can use the :term:`BBMASK` variable to "hide" these ``.bb`` and
``.bbappend`` files. BitBake ignores any recipe or recipe append
files that match any of the expressions. It is as if BitBake does not
see them at all. Consequently, matching files are not parsed or
otherwise used by BitBake.
The values you provide are passed to Python's regular expression
compiler. Consequently, the syntax follows Python's Regular
Expression (re) syntax. The expressions are compared against the full
paths to the files. For complete syntax information, see Python's
documentation at https://docs.python.org/3/library/re.html#regular-expression-syntax.
The following example uses a complete regular expression to tell
BitBake to ignore all recipe and recipe append files in the
``meta-ti/recipes-misc/`` directory::
BBMASK = "meta-ti/recipes-misc/"
If you want to mask out multiple directories or recipes, you can
specify multiple regular expression fragments. This next example
masks out multiple directories and individual recipes::
BBMASK += "/meta-ti/recipes-misc/ meta-ti/recipes-ti/packagegroup/"
BBMASK += "/meta-oe/recipes-support/"
BBMASK += "/meta-foo/.*/openldap"
BBMASK += "opencv.*\.bbappend"
BBMASK += "lzma"
.. note::
When specifying a directory name, use the trailing slash character
to ensure you match just that directory name.
:term:`BBMULTICONFIG`
Specifies each additional separate configuration when you are
building targets with multiple configurations. Use this variable in
your ``conf/local.conf`` configuration file. Specify a
multiconfigname for each configuration file you are using. For
example, the following line specifies three configuration files::
BBMULTICONFIG = "configA configB configC"
Each configuration file you use must reside in a ``multiconfig``
subdirectory of a configuration directory within a layer, or
within the :term:`Build Directory` (e.g.
``build_directory/conf/multiconfig/configA.conf`` or
``mylayer/conf/multiconfig/configB.conf``).
For information on how to use :term:`BBMULTICONFIG` in an environment
that supports building targets with multiple configurations, see the
":ref:`dev-manual/building:building images for multiple targets using multiple configurations`"
section in the Yocto Project Development Tasks Manual.
:term:`BBPATH`
See :term:`bitbake:BBPATH` in the BitBake manual.
:term:`BBSERVER`
If defined in the BitBake environment, :term:`BBSERVER` points to the
BitBake remote server.
Use the following format to export the variable to the BitBake
environment::
export BBSERVER=localhost:$port
By default, :term:`BBSERVER` also appears in :term:`BB_BASEHASH_IGNORE_VARS`.
Consequently, :term:`BBSERVER` is excluded from checksum and dependency
data.
:term:`BBTARGETS`
See :term:`bitbake:BBTARGETS` in the BitBake manual.
:term:`BINCONFIG`
When inheriting the :ref:`ref-classes-binconfig-disabled` class, this
variable specifies binary configuration scripts to disable in favor of
using ``pkg-config`` to query the information. The
:ref:`ref-classes-binconfig-disabled` class will modify the specified
scripts to return an error so that calls to them can be easily found
and replaced.
To add multiple scripts, separate them by spaces. Here is an example
from the ``libpng`` recipe::
BINCONFIG = "${bindir}/libpng-config ${bindir}/libpng16-config"
:term:`BINCONFIG_GLOB`
When inheriting the :ref:`ref-classes-binconfig` class,
this variable specifies a wildcard for configuration scripts that
need editing. The scripts are edited to correct any paths that have
been set up during compilation so that they are correct for use when
installed into the sysroot and called by the build processes of other
recipes.
.. note::
The :term:`BINCONFIG_GLOB` variable uses
`shell globbing <https://tldp.org/LDP/abs/html/globbingref.html>`__,
which is recognition and expansion of wildcards during pattern
matching. Shell globbing is very similar to
`fnmatch <https://docs.python.org/3/library/fnmatch.html#module-fnmatch>`__
and `glob <https://docs.python.org/3/library/glob.html>`__.
For more information on how this variable works, see
``meta/classes-recipe/binconfig.bbclass`` in the :term:`Source Directory`.
You can also find general
information on the class in the
":ref:`ref-classes-binconfig`" section.
:term:`BITBAKE_UI`
See :term:`bitbake:BITBAKE_UI` in the BitBake manual.
:term:`BP`
The base recipe name and version but without any special recipe name
suffix (i.e. ``-native``, ``lib64-``, and so forth). :term:`BP` is
comprised of the following::
${BPN}-${PV}
:term:`BPN`
This variable is a version of the :term:`PN` variable with
common prefixes and suffixes removed, such as ``nativesdk-``,
``-cross``, ``-native``, and multilib's ``lib64-`` and ``lib32-``.
The exact lists of prefixes and suffixes removed are specified by the
:term:`MLPREFIX` and
:term:`SPECIAL_PKGSUFFIX` variables,
respectively.
:term:`BUGTRACKER`
Specifies a URL for an upstream bug tracking website for a recipe.
The OpenEmbedded build system does not use this variable. Rather, the
variable is a useful pointer in case a bug in the software being
built needs to be manually reported.
:term:`BUILD_ARCH`
Specifies the architecture of the build host (e.g. ``i686``). The
OpenEmbedded build system sets the value of :term:`BUILD_ARCH` from the
machine name reported by the ``uname`` command.
:term:`BUILD_AS_ARCH`
Specifies the architecture-specific assembler flags for the build
host. By default, the value of :term:`BUILD_AS_ARCH` is empty.
:term:`BUILD_CC_ARCH`
Specifies the architecture-specific C compiler flags for the build
host. By default, the value of :term:`BUILD_CC_ARCH` is empty.
:term:`BUILD_CCLD`
Specifies the linker command to be used for the build host when the C
compiler is being used as the linker. By default, :term:`BUILD_CCLD`
points to GCC and passes as arguments the value of
:term:`BUILD_CC_ARCH`, assuming
:term:`BUILD_CC_ARCH` is set.
:term:`BUILD_CFLAGS`
Specifies the flags to pass to the C compiler when building for the
build host. When building in the ``-native`` context,
:term:`CFLAGS` is set to the value of this variable by
default.
:term:`BUILD_CPPFLAGS`
Specifies the flags to pass to the C preprocessor (i.e. to both the C
and the C++ compilers) when building for the build host. When
building in the ``-native`` context, :term:`CPPFLAGS`
is set to the value of this variable by default.
:term:`BUILD_CXXFLAGS`
Specifies the flags to pass to the C++ compiler when building for the
build host. When building in the ``-native`` context,
:term:`CXXFLAGS` is set to the value of this variable
by default.
:term:`BUILD_FC`
Specifies the Fortran compiler command for the build host. By
default, :term:`BUILD_FC` points to Gfortran and passes as arguments the
value of :term:`BUILD_CC_ARCH`, assuming
:term:`BUILD_CC_ARCH` is set.
:term:`BUILD_LD`
Specifies the linker command for the build host. By default,
:term:`BUILD_LD` points to the GNU linker (ld) and passes as arguments
the value of :term:`BUILD_LD_ARCH`, assuming
:term:`BUILD_LD_ARCH` is set.
:term:`BUILD_LD_ARCH`
Specifies architecture-specific linker flags for the build host. By
default, the value of :term:`BUILD_LD_ARCH` is empty.
:term:`BUILD_LDFLAGS`
Specifies the flags to pass to the linker when building for the build
host. When building in the ``-native`` context,
:term:`LDFLAGS` is set to the value of this variable
by default.
:term:`BUILD_OPTIMIZATION`
Specifies the optimization flags passed to the C compiler when
building for the build host or the SDK. The flags are passed through
the :term:`BUILD_CFLAGS` and
:term:`BUILDSDK_CFLAGS` default values.
The default value of the :term:`BUILD_OPTIMIZATION` variable is "-O2
-pipe".
:term:`BUILD_OS`
Specifies the operating system in use on the build host (e.g.
"linux"). The OpenEmbedded build system sets the value of
:term:`BUILD_OS` from the OS reported by the ``uname`` command --- the
first word, converted to lower-case characters.
:term:`BUILD_PREFIX`
The toolchain binary prefix used for native recipes. The OpenEmbedded
build system uses the :term:`BUILD_PREFIX` value to set the
:term:`TARGET_PREFIX` when building for :ref:`ref-classes-native` recipes.
:term:`BUILD_STRIP`
Specifies the command to be used to strip debugging symbols from
binaries produced for the build host. By default, :term:`BUILD_STRIP`
points to
``${``\ :term:`BUILD_PREFIX`\ ``}strip``.
:term:`BUILD_SYS`
Specifies the system, including the architecture and the operating
system, to use when building for the build host (i.e. when building
:ref:`ref-classes-native` recipes).
The OpenEmbedded build system automatically sets this variable based
on :term:`BUILD_ARCH`,
:term:`BUILD_VENDOR`, and
:term:`BUILD_OS`. You do not need to set the
:term:`BUILD_SYS` variable yourself.
:term:`BUILD_VENDOR`
Specifies the vendor name to use when building for the build host.
The default value is an empty string ("").
:term:`BUILDDIR`
Points to the location of the :term:`Build Directory`. You can define
this directory indirectly through the :ref:`structure-core-script` script
by passing in a :term:`Build Directory` path when you run the script. If
you run the script and do not provide a :term:`Build Directory` path, the
:term:`BUILDDIR` defaults to ``build`` in the current directory.
:term:`BUILDHISTORY_COMMIT`
When inheriting the :ref:`ref-classes-buildhistory` class, this variable
specifies whether or not to commit the build history output in a local
Git repository. If set to "1", this local repository will be maintained
automatically by the :ref:`ref-classes-buildhistory` class and a commit
will be created on every build for changes to each top-level subdirectory
of the build history output (images, packages, and sdk). If you want to
track changes to build history over time, you should set this value to
"1".
By default, the :ref:`ref-classes-buildhistory` class
enables committing the buildhistory output in a local Git repository::
BUILDHISTORY_COMMIT ?= "1"
:term:`BUILDHISTORY_COMMIT_AUTHOR`
When inheriting the :ref:`ref-classes-buildhistory`
class, this variable specifies the author to use for each Git commit.
In order for the :term:`BUILDHISTORY_COMMIT_AUTHOR` variable to work, the
:term:`BUILDHISTORY_COMMIT` variable must
be set to "1".
Git requires that the value you provide for the
:term:`BUILDHISTORY_COMMIT_AUTHOR` variable takes the form of "name
email@host". Providing an email address or host that is not valid
does not produce an error.
By default, the :ref:`ref-classes-buildhistory` class sets the variable
as follows::
BUILDHISTORY_COMMIT_AUTHOR ?= "buildhistory <buildhistory@${DISTRO}>"
:term:`BUILDHISTORY_DIR`
When inheriting the :ref:`ref-classes-buildhistory`
class, this variable specifies the directory in which build history
information is kept. For more information on how the variable works,
see the :ref:`ref-classes-buildhistory` class.
By default, the :ref:`ref-classes-buildhistory` class sets the directory
as follows::
BUILDHISTORY_DIR ?= "${TOPDIR}/buildhistory"
:term:`BUILDHISTORY_FEATURES`
When inheriting the :ref:`ref-classes-buildhistory`
class, this variable specifies the build history features to be
enabled. For more information on how build history works, see the
":ref:`dev-manual/build-quality:maintaining build output quality`"
section in the Yocto Project Development Tasks Manual.
You can specify these features in the form of a space-separated list:
- *image:* Analysis of the contents of images, which includes the
list of installed packages among other things.
- *package:* Analysis of the contents of individual packages.
- *sdk:* Analysis of the contents of the software development kit
(SDK).
- *task:* Save output file signatures for
:ref:`shared state <overview-manual/concepts:shared state cache>`
(sstate) tasks.
This saves one file per task and lists the SHA-256 checksums for
each file staged (i.e. the output of the task).
By default, the :ref:`ref-classes-buildhistory` class enables the
following features::
BUILDHISTORY_FEATURES ?= "image package sdk"
:term:`BUILDHISTORY_IMAGE_FILES`
When inheriting the :ref:`ref-classes-buildhistory`
class, this variable specifies a list of paths to files copied from
the image contents into the build history directory under an
"image-files" directory in the directory for the image, so that you
can track the contents of each file. The default is to copy
``/etc/passwd`` and ``/etc/group``, which allows you to monitor for
changes in user and group entries. You can modify the list to include
any file. Specifying an invalid path does not produce an error.
Consequently, you can include files that might not always be present.
By default, the :ref:`ref-classes-buildhistory` class provides paths to
the following files::
BUILDHISTORY_IMAGE_FILES ?= "/etc/passwd /etc/group"
:term:`BUILDHISTORY_PATH_PREFIX_STRIP`
When inheriting the :ref:`ref-classes-buildhistory`
class, this variable specifies a common path prefix that should be
stripped off the beginning of paths in the task signature list when the
``task`` feature is active in :term:`BUILDHISTORY_FEATURES`. This can be
useful when build history is populated from multiple sources that may not
all use the same top level directory.
By default, the :ref:`ref-classes-buildhistory` class sets the variable
as follows::
BUILDHISTORY_PATH_PREFIX_STRIP ?= ""
In this case, no prefixes will be stripped.
:term:`BUILDHISTORY_PUSH_REPO`
When inheriting the :ref:`ref-classes-buildhistory` class, this variable
optionally specifies a remote repository to which build history pushes
Git changes. In order for :term:`BUILDHISTORY_PUSH_REPO` to work,
:term:`BUILDHISTORY_COMMIT` must be set to "1".
The repository should correspond to a remote address that specifies a
repository as understood by Git, or alternatively to a remote name
that you have set up manually using ``git remote`` within the local
repository.
By default, the :ref:`ref-classes-buildhistory` class sets the variable
as follows::
BUILDHISTORY_PUSH_REPO ?= ""
:term:`BUILDNAME`
See :term:`bitbake:BUILDNAME` in the BitBake manual.
:term:`BUILDSDK_CFLAGS`
Specifies the flags to pass to the C compiler when building for the
SDK. When building in the ``nativesdk-`` context,
:term:`CFLAGS` is set to the value of this variable by
default.
:term:`BUILDSDK_CPPFLAGS`
Specifies the flags to pass to the C pre-processor (i.e. to both the
C and the C++ compilers) when building for the SDK. When building in
the ``nativesdk-`` context, :term:`CPPFLAGS` is set
to the value of this variable by default.
:term:`BUILDSDK_CXXFLAGS`
Specifies the flags to pass to the C++ compiler when building for the
SDK. When building in the ``nativesdk-`` context,
:term:`CXXFLAGS` is set to the value of this variable
by default.
:term:`BUILDSDK_LDFLAGS`
Specifies the flags to pass to the linker when building for the SDK.
When building in the ``nativesdk-`` context,
:term:`LDFLAGS` is set to the value of this variable
by default.
:term:`BUILDSTATS_BASE`
Points to the location of the directory that holds build statistics
when you use and enable the :ref:`ref-classes-buildstats` class. The
:term:`BUILDSTATS_BASE` directory defaults to
``${``\ :term:`TMPDIR`\ ``}/buildstats/``.
:term:`BUSYBOX_SPLIT_SUID`
For the BusyBox recipe, specifies whether to split the output
executable file into two parts: one for features that require
``setuid root``, and one for the remaining features (i.e. those that
do not require ``setuid root``).
The :term:`BUSYBOX_SPLIT_SUID` variable defaults to "1", which results in
splitting the output executable file. Set the variable to "0" to get
a single output executable file.
:term:`BZRDIR`
See :term:`bitbake:BZRDIR` in the BitBake manual.
:term:`CACHE`
Specifies the directory BitBake uses to store a cache of the
:term:`Metadata` so it does not need to be parsed every time
BitBake is started.
:term:`CC`
The minimal command and arguments used to run the C compiler.
:term:`CFLAGS`
Specifies the flags to pass to the C compiler. This variable is
exported to an environment variable and thus made visible to the
software being built during the compilation step.
Default initialization for :term:`CFLAGS` varies depending on what is
being built:
- :term:`TARGET_CFLAGS` when building for the
target
- :term:`BUILD_CFLAGS` when building for the
build host (i.e. ``-native``)
- :term:`BUILDSDK_CFLAGS` when building for
an SDK (i.e. ``nativesdk-``)
:term:`CLASSOVERRIDE`
An internal variable specifying the special class override that
should currently apply (e.g. "class-target", "class-native", and so
forth). The classes that use this variable (e.g.
:ref:`ref-classes-native`, :ref:`ref-classes-nativesdk`, and so forth)
set the variable to appropriate values.
.. note::
:term:`CLASSOVERRIDE` gets its default "class-target" value from the
``bitbake.conf`` file.
As an example, the following override allows you to install extra
files, but only when building for the target::
do_install:append:class-target() {
install my-extra-file ${D}${sysconfdir}
}
Here is an example where ``FOO`` is set to
"native" when building for the build host, and to "other" when not
building for the build host::
FOO:class-native = "native"
FOO = "other"
The underlying mechanism behind :term:`CLASSOVERRIDE` is simply
that it is included in the default value of
:term:`OVERRIDES`.
:term:`CLEANBROKEN`
If set to "1" within a recipe, :term:`CLEANBROKEN` specifies that the
``make clean`` command does not work for the software being built.
Consequently, the OpenEmbedded build system will not try to run
``make clean`` during the :ref:`ref-tasks-configure`
task, which is the default behavior.
:term:`COMBINED_FEATURES`
Provides a list of hardware features that are enabled in both
:term:`MACHINE_FEATURES` and
:term:`DISTRO_FEATURES`. This select list of
features contains features that make sense to be controlled both at
the machine and distribution configuration level. For example, the
"bluetooth" feature requires hardware support but should also be
optional at the distribution level, in case the hardware supports
Bluetooth but you do not ever intend to use it.
:term:`COMMON_LICENSE_DIR`
Points to ``meta/files/common-licenses`` in the
:term:`Source Directory`, which is where generic license
files reside.
:term:`COMPATIBLE_HOST`
A regular expression that resolves to one or more hosts (when the
recipe is native) or one or more targets (when the recipe is
non-native) with which a recipe is compatible. The regular expression
is matched against :term:`HOST_SYS`. You can use the
variable to stop recipes from being built for classes of systems with
which the recipes are not compatible. Stopping these builds is
particularly useful with kernels. The variable also helps to increase
parsing speed since the build system skips parsing recipes not
compatible with the current system.
:term:`COMPATIBLE_MACHINE`
A regular expression that resolves to one or more target machines
with which a recipe is compatible. The regular expression is matched
against :term:`MACHINEOVERRIDES`. You can use
the variable to stop recipes from being built for machines with which
the recipes are not compatible. Stopping these builds is particularly
useful with kernels. The variable also helps to increase parsing
speed since the build system skips parsing recipes not compatible
with the current machine.
:term:`COMPLEMENTARY_GLOB`
Defines wildcards to match when installing a list of complementary
packages for all the packages explicitly (or implicitly) installed in
an image.
The :term:`COMPLEMENTARY_GLOB` variable uses Unix filename pattern matching
(`fnmatch <https://docs.python.org/3/library/fnmatch.html#module-fnmatch>`__),
which is similar to the Unix style pathname pattern expansion
(`glob <https://docs.python.org/3/library/glob.html>`__).
The resulting list of complementary packages is associated with an
item that can be added to
:term:`IMAGE_FEATURES`. An example usage of
this is the "dev-pkgs" item that when added to :term:`IMAGE_FEATURES`
will install -dev packages (containing headers and other development
files) for every package in the image.
To add a new feature item pointing to a wildcard, use a variable flag
to specify the feature item name and use the value to specify the
wildcard. Here is an example::
COMPLEMENTARY_GLOB[dev-pkgs] = '*-dev'
.. note::
When installing complementary packages, recommends relationships
(set via :term:`RRECOMMENDS`) are always ignored.
:term:`COMPONENTS_DIR`
Stores sysroot components for each recipe. The OpenEmbedded build
system uses :term:`COMPONENTS_DIR` when constructing recipe-specific
sysroots for other recipes.
The default is
"``${``\ :term:`STAGING_DIR`\ ``}-components``."
(i.e.
"``${``\ :term:`TMPDIR`\ ``}/sysroots-components``").
:term:`CONF_VERSION`
Tracks the version of the local configuration file (i.e.
``local.conf``). The value for :term:`CONF_VERSION` increments each time
``build/conf/`` compatibility changes.
:term:`CONFFILES`
Identifies editable or configurable files that are part of a package.
If the Package Management System (PMS) is being used to update
packages on the target system, it is possible that configuration
files you have changed after the original installation and that you
now want to remain unchanged are overwritten. In other words,
editable files might exist in the package that you do not want reset
as part of the package update process. You can use the :term:`CONFFILES`
variable to list the files in the package that you wish to prevent
the PMS from overwriting during this update process.
To use the :term:`CONFFILES` variable, provide a package name override
that identifies the resulting package. Then, provide a
space-separated list of files. Here is an example::
CONFFILES:${PN} += "${sysconfdir}/file1 \
${sysconfdir}/file2 ${sysconfdir}/file3"
There is a relationship between the :term:`CONFFILES` and :term:`FILES`
variables. The files listed within :term:`CONFFILES` must be a subset of
the files listed within :term:`FILES`. Because the configuration files
you provide with :term:`CONFFILES` are simply being identified so that
the PMS will not overwrite them, it makes sense that the files must
already be included as part of the package through the :term:`FILES`
variable.
.. note::
When specifying paths as part of the :term:`CONFFILES` variable, it is
good practice to use appropriate path variables.
For example, ``${sysconfdir}`` rather than ``/etc`` or ``${bindir}``
rather than ``/usr/bin``. You can find a list of these variables at
the top of the ``meta/conf/bitbake.conf`` file in the
:term:`Source Directory`.
:term:`CONFIG_INITRAMFS_SOURCE`
Identifies the initial RAM filesystem (:term:`Initramfs`) source files. The
OpenEmbedded build system receives and uses this kernel Kconfig
variable as an environment variable. By default, the variable is set
to null ("").
The :term:`CONFIG_INITRAMFS_SOURCE` can be either a single cpio archive
with a ``.cpio`` suffix or a space-separated list of directories and
files for building the :term:`Initramfs` image. A cpio archive should contain
a filesystem archive to be used as an :term:`Initramfs` image. Directories
should contain a filesystem layout to be included in the :term:`Initramfs`
image. Files should contain entries according to the format described
by the ``usr/gen_init_cpio`` program in the kernel tree.
If you specify multiple directories and files, the :term:`Initramfs` image
will be the aggregate of all of them.
For information on creating an :term:`Initramfs`, see the
":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`" section
in the Yocto Project Development Tasks Manual.
:term:`CONFIG_SITE`
A list of files that contains ``autoconf`` test results relevant to
the current build. This variable is used by the Autotools utilities
when running ``configure``.
:term:`CONFIGURE_FLAGS`
The minimal arguments for GNU configure.
:term:`CONFLICT_DISTRO_FEATURES`
When inheriting the :ref:`ref-classes-features_check`
class, this variable identifies distribution features that would be
in conflict should the recipe be built. In other words, if the
:term:`CONFLICT_DISTRO_FEATURES` variable lists a feature that also
appears in :term:`DISTRO_FEATURES` within the current configuration, then
the recipe will be skipped, and if the build system attempts to build
the recipe then an error will be triggered.
:term:`CONVERSION_CMD`
This variable is used for storing image conversion commands.
Image conversion can convert an image into different objects like:
- Compressed version of the image
- Checksums for the image
An example of :term:`CONVERSION_CMD` from :ref:`ref-classes-image_types`
class is::
CONVERSION_CMD:lzo = "lzop -9 ${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.${type}"
:term:`COPY_LIC_DIRS`
If set to "1" along with the
:term:`COPY_LIC_MANIFEST` variable, the
OpenEmbedded build system copies into the image the license files,
which are located in ``/usr/share/common-licenses``, for each
package. The license files are placed in directories within the image
itself during build time.
.. note::
The :term:`COPY_LIC_DIRS` does not offer a path for adding licenses for
newly installed packages to an image, which might be most suitable for
read-only filesystems that cannot be upgraded. See the
:term:`LICENSE_CREATE_PACKAGE` variable for additional information.
You can also reference the ":ref:`dev-manual/licenses:providing license text`"
section in the Yocto Project Development Tasks Manual for
information on providing license text.
:term:`COPY_LIC_MANIFEST`
If set to "1", the OpenEmbedded build system copies the license
manifest for the image to
``/usr/share/common-licenses/license.manifest`` within the image
itself during build time.
.. note::
The :term:`COPY_LIC_MANIFEST` does not offer a path for adding licenses for
newly installed packages to an image, which might be most suitable for
read-only filesystems that cannot be upgraded. See the
:term:`LICENSE_CREATE_PACKAGE` variable for additional information.
You can also reference the ":ref:`dev-manual/licenses:providing license text`"
section in the Yocto Project Development Tasks Manual for
information on providing license text.
:term:`COPYLEFT_LICENSE_EXCLUDE`
A space-separated list of licenses to exclude from the source archived by
the :ref:`ref-classes-archiver` class. In other words, if a license in a
recipe's :term:`LICENSE` value is in the value of
:term:`COPYLEFT_LICENSE_EXCLUDE`, then its source is not archived by the
class.
.. note::
The :term:`COPYLEFT_LICENSE_EXCLUDE` variable takes precedence over the
:term:`COPYLEFT_LICENSE_INCLUDE` variable.
The default value, which is "CLOSED Proprietary", for
:term:`COPYLEFT_LICENSE_EXCLUDE` is set by the
:ref:`ref-classes-copyleft_filter` class, which
is inherited by the :ref:`ref-classes-archiver` class.
:term:`COPYLEFT_LICENSE_INCLUDE`
A space-separated list of licenses to include in the source archived
by the :ref:`ref-classes-archiver` class. In other
words, if a license in a recipe's :term:`LICENSE`
value is in the value of :term:`COPYLEFT_LICENSE_INCLUDE`, then its
source is archived by the class.
The default value is set by the :ref:`ref-classes-copyleft_filter` class,
which is inherited by the :ref:`ref-classes-archiver` class. The default
value includes "GPL*", "LGPL*", and "AGPL*".
:term:`COPYLEFT_PN_EXCLUDE`
A list of recipes to exclude in the source archived by the
:ref:`ref-classes-archiver` class. The :term:`COPYLEFT_PN_EXCLUDE`
variable overrides the license inclusion and exclusion caused through the
:term:`COPYLEFT_LICENSE_INCLUDE` and :term:`COPYLEFT_LICENSE_EXCLUDE`
variables, respectively.
The default value, which is "" indicating to not explicitly exclude
any recipes by name, for :term:`COPYLEFT_PN_EXCLUDE` is set by the
:ref:`ref-classes-copyleft_filter` class, which is inherited by the
:ref:`ref-classes-archiver` class.
:term:`COPYLEFT_PN_INCLUDE`
A list of recipes to include in the source archived by the
:ref:`ref-classes-archiver` class. The :term:`COPYLEFT_PN_INCLUDE`
variable overrides the license inclusion and exclusion caused through the
:term:`COPYLEFT_LICENSE_INCLUDE` and :term:`COPYLEFT_LICENSE_EXCLUDE`
variables, respectively.
The default value, which is "" indicating to not explicitly include
any recipes by name, for :term:`COPYLEFT_PN_INCLUDE` is set by the
:ref:`ref-classes-copyleft_filter` class, which is inherited by the
:ref:`ref-classes-archiver` class.
:term:`COPYLEFT_RECIPE_TYPES`
A space-separated list of recipe types to include in the source
archived by the :ref:`archiver <ref-classes-archiver>` class.
Recipe types are ``target``, :ref:`ref-classes-native`,
:ref:`ref-classes-nativesdk`, :ref:`ref-classes-cross`,
:ref:`ref-classes-crosssdk`, and :ref:`ref-classes-cross-canadian`.
The default value, which is "target*", for :term:`COPYLEFT_RECIPE_TYPES`
is set by the :ref:`ref-classes-copyleft_filter` class, which is
inherited by the :ref:`ref-classes-archiver` class.
:term:`CORE_IMAGE_EXTRA_INSTALL`
Specifies the list of packages to be added to the image. You should
only set this variable in the ``local.conf`` configuration file found
in the :term:`Build Directory`.
This variable replaces ``POKY_EXTRA_INSTALL``, which is no longer
supported.
:term:`COREBASE`
Specifies the parent directory of the OpenEmbedded-Core Metadata
layer (i.e. ``meta``).
It is an important distinction that :term:`COREBASE` points to the parent
of this layer and not the layer itself. Consider an example where you
have cloned the Poky Git repository and retained the ``poky`` name
for your local copy of the repository. In this case, :term:`COREBASE`
points to the ``poky`` folder because it is the parent directory of
the ``poky/meta`` layer.
:term:`COREBASE_FILES`
Lists files from the :term:`COREBASE` directory that
should be copied other than the layers listed in the
``bblayers.conf`` file. The :term:`COREBASE_FILES` variable allows
to copy metadata from the OpenEmbedded build system
into the extensible SDK.
Explicitly listing files in :term:`COREBASE` is needed because it
typically contains build directories and other files that should not
normally be copied into the extensible SDK. Consequently, the value
of :term:`COREBASE_FILES` is used in order to only copy the files that
are actually needed.
:term:`CPP`
The minimal command and arguments used to run the C preprocessor.
:term:`CPPFLAGS`
Specifies the flags to pass to the C pre-processor (i.e. to both the
C and the C++ compilers). This variable is exported to an environment
variable and thus made visible to the software being built during the
compilation step.
Default initialization for :term:`CPPFLAGS` varies depending on what is
being built:
- :term:`TARGET_CPPFLAGS` when building for
the target
- :term:`BUILD_CPPFLAGS` when building for the
build host (i.e. ``-native``)
- :term:`BUILDSDK_CPPFLAGS` when building
for an SDK (i.e. ``nativesdk-``)
:term:`CROSS_COMPILE`
The toolchain binary prefix for the target tools. The
:term:`CROSS_COMPILE` variable is the same as the
:term:`TARGET_PREFIX` variable.
.. note::
The OpenEmbedded build system sets the :term:`CROSS_COMPILE`
variable only in certain contexts (e.g. when building for kernel
and kernel module recipes).
:term:`CVE_CHECK_IGNORE`
The list of CVE IDs which are ignored. Here is
an example from the :oe_layerindex:`Python3 recipe</layerindex/recipe/23823>`::
# This is windows only issue.
CVE_CHECK_IGNORE += "CVE-2020-15523"
:term:`CVE_CHECK_SHOW_WARNINGS`
Specifies whether or not the :ref:`ref-classes-cve-check`
class should generate warning messages on the console when unpatched
CVEs are found. The default is "1", but you may wish to set it to "0" if
you are already examining/processing the logs after the build has
completed and thus do not need the warning messages.
:term:`CVE_CHECK_SKIP_RECIPE`
The list of package names (:term:`PN`) for which
CVEs (Common Vulnerabilities and Exposures) are ignored.
:term:`CVE_DB_UPDATE_INTERVAL`
Specifies the CVE database update interval in seconds, as used by
``cve-update-db-native``. The default value is "86400" i.e. once a day
(24*60*60). If the value is set to "0" then the update will be forced
every time. Alternatively, a negative value e.g. "-1" will disable
updates entirely.
:term:`CVE_PRODUCT`
In a recipe, defines the name used to match the recipe name
against the name in the upstream `NIST CVE database <https://nvd.nist.gov/>`__.
The default is ${:term:`BPN`} (except for recipes that inherit the
:ref:`ref-classes-pypi` class where it is set based upon
:term:`PYPI_PACKAGE`). If it does not match the name in the NIST CVE
database or matches with multiple entries in the database, the default
value needs to be changed.
Here is an example from the :oe_layerindex:`Berkeley DB recipe </layerindex/recipe/544>`::
CVE_PRODUCT = "oracle_berkeley_db berkeley_db"
Sometimes the product name is not specific enough, for example
"tar" has been matching CVEs for the GNU ``tar`` package and also
the ``node-tar`` node.js extension. To avoid this problem, use the
vendor name as a prefix. The syntax for this is::
CVE_PRODUCT = "vendor:package"
:term:`CVE_VERSION`
In a recipe, defines the version used to match the recipe version
against the version in the `NIST CVE database <https://nvd.nist.gov/>`__
when usign :ref:`ref-classes-cve-check`.
The default is ${:term:`PV`} but if recipes use custom version numbers
which do not map to upstream software component release versions and the versions
used in the CVE database, then this variable can be used to set the
version number for :ref:`ref-classes-cve-check`. Example::
CVE_VERSION = "2.39"
:term:`CVSDIR`
The directory in which files checked out under the CVS system are
stored.
:term:`CXX`
The minimal command and arguments used to run the C++ compiler.
:term:`CXXFLAGS`
Specifies the flags to pass to the C++ compiler. This variable is
exported to an environment variable and thus made visible to the
software being built during the compilation step.
Default initialization for :term:`CXXFLAGS` varies depending on what is
being built:
- :term:`TARGET_CXXFLAGS` when building for
the target
- :term:`BUILD_CXXFLAGS` when building for the
build host (i.e. ``-native``)
- :term:`BUILDSDK_CXXFLAGS` when building
for an SDK (i.e. ``nativesdk-``)
:term:`D`
The destination directory. The location in the :term:`Build Directory`
where components are installed by the
:ref:`ref-tasks-install` task. This location defaults
to::
${WORKDIR}/image
.. note::
Tasks that read from or write to this directory should run under
:ref:`fakeroot <overview-manual/concepts:fakeroot and pseudo>`.
:term:`DATE`
The date the build was started. Dates appear using the year, month,
and day (YMD) format (e.g. "20150209" for February 9th, 2015).
:term:`DATETIME`
The date and time on which the current build started. The format is
suitable for timestamps.
:term:`DEBIAN_NOAUTONAME`
When the :ref:`ref-classes-debian` class is inherited,
which is the default behavior, :term:`DEBIAN_NOAUTONAME` specifies a
particular package should not be renamed according to Debian library
package naming. You must use the package name as an override when you
set this variable. Here is an example from the ``fontconfig`` recipe::
DEBIAN_NOAUTONAME:fontconfig-utils = "1"
:term:`DEBIANNAME`
When the :ref:`ref-classes-debian` class is inherited,
which is the default behavior, :term:`DEBIANNAME` allows you to override
the library name for an individual package. Overriding the library
name in these cases is rare. You must use the package name as an
override when you set this variable. Here is an example from the
``dbus`` recipe::
DEBIANNAME:${PN} = "dbus-1"
:term:`DEBUG_BUILD`
Specifies to build packages with debugging information. This
influences the value of the :term:`SELECTED_OPTIMIZATION` variable.
:term:`DEBUG_OPTIMIZATION`
The options to pass in :term:`TARGET_CFLAGS` and :term:`CFLAGS` when
compiling a system for debugging. This variable defaults to "-O
-fno-omit-frame-pointer ${DEBUG_FLAGS} -pipe".
:term:`DEBUG_PREFIX_MAP`
Allows to set C compiler options, such as ``-fdebug-prefix-map``,
``-fmacro-prefix-map``, and ``-ffile-prefix-map``, which allow to
replace build-time paths by install-time ones in the debugging sections
of binaries. This makes compiler output files location independent,
at the cost of having to pass an extra command to tell the debugger
where source files are.
This is used by the Yocto Project to guarantee
:doc:`/test-manual/reproducible-builds` even when the source code of
a package uses the ``__FILE__`` or ``assert()`` macros. See the
`reproducible-builds.org <https://reproducible-builds.org/docs/build-path/>`__
website for details.
This variable is set in the ``meta/conf/bitbake.conf`` file. It is
not intended to be user-configurable.
:term:`DEFAULT_PREFERENCE`
Specifies a weak bias for recipe selection priority.
The most common usage of this is variable is to set it to "-1" within
a recipe for a development version of a piece of software. Using the
variable in this way causes the stable version of the recipe to build
by default in the absence of :term:`PREFERRED_VERSION` being used to
build the development version.
.. note::
The bias provided by :term:`DEFAULT_PREFERENCE` is weak and is overridden
by :term:`BBFILE_PRIORITY` if that variable is different between two
layers that contain different versions of the same recipe.
:term:`DEFAULTTUNE`
The default CPU and Application Binary Interface (ABI) tunings (i.e.
the "tune") used by the OpenEmbedded build system. The
:term:`DEFAULTTUNE` helps define
:term:`TUNE_FEATURES`.
The default tune is either implicitly or explicitly set by the
machine (:term:`MACHINE`). However, you can override
the setting using available tunes as defined with
:term:`AVAILTUNES`.
:term:`DEPENDS`
Lists a recipe's build-time dependencies. These are dependencies on
other recipes whose contents (e.g. headers and shared libraries) are
needed by the recipe at build time.
As an example, consider a recipe ``foo`` that contains the following
assignment::
DEPENDS = "bar"
The practical effect of the previous
assignment is that all files installed by bar will be available in
the appropriate staging sysroot, given by the
:term:`STAGING_DIR* <STAGING_DIR>` variables, by the time the
:ref:`ref-tasks-configure` task for ``foo`` runs.
This mechanism is implemented by having :ref:`ref-tasks-configure` depend on
the :ref:`ref-tasks-populate_sysroot` task of
each recipe listed in :term:`DEPENDS`, through a
``[``\ :ref:`deptask <bitbake:bitbake-user-manual/bitbake-user-manual-metadata:variable flags>`\ ``]``
declaration in the :ref:`ref-classes-base` class.
.. note::
It seldom is necessary to reference, for example, :term:`STAGING_DIR_HOST`
explicitly. The standard classes and build-related variables are
configured to automatically use the appropriate staging sysroots.
As another example, :term:`DEPENDS` can also be used to add utilities
that run on the build machine during the build. For example, a recipe
that makes use of a code generator built by the recipe ``codegen``
might have the following::
DEPENDS = "codegen-native"
For more
information, see the :ref:`ref-classes-native` class and
the :term:`EXTRANATIVEPATH` variable.
.. note::
- :term:`DEPENDS` is a list of recipe names. Or, to be more precise,
it is a list of :term:`PROVIDES` names, which
usually match recipe names. Putting a package name such as
"foo-dev" in :term:`DEPENDS` does not make sense. Use "foo"
instead, as this will put files from all the packages that make
up ``foo``, which includes those from ``foo-dev``, into the
sysroot.
- One recipe having another recipe in :term:`DEPENDS` does not by
itself add any runtime dependencies between the packages
produced by the two recipes. However, as explained in the
":ref:`overview-manual/concepts:automatically added runtime dependencies`"
section in the Yocto Project Overview and Concepts Manual,
runtime dependencies will often be added automatically, meaning
:term:`DEPENDS` alone is sufficient for most recipes.
- Counterintuitively, :term:`DEPENDS` is often necessary even for
recipes that install precompiled components. For example, if
``libfoo`` is a precompiled library that links against
``libbar``, then linking against ``libfoo`` requires both
``libfoo`` and ``libbar`` to be available in the sysroot.
Without a :term:`DEPENDS` from the recipe that installs ``libfoo``
to the recipe that installs ``libbar``, other recipes might
fail to link against ``libfoo``.
For information on runtime dependencies, see the
:term:`RDEPENDS` variable. You can also see the
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:tasks`" and
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-execution:dependencies`" sections in the
BitBake User Manual for additional information on tasks and
dependencies.
:term:`DEPLOY_DIR`
Points to the general area that the OpenEmbedded build system uses to
place images, packages, SDKs, and other output files that are ready
to be used outside of the build system. By default, this directory
resides within the :term:`Build Directory` as ``${TMPDIR}/deploy``.
For more information on the structure of the Build Directory, see
":ref:`ref-manual/structure:the build directory --- \`\`build/\`\``" section.
For more detail on the contents of the ``deploy`` directory, see the
":ref:`overview-manual/concepts:images`",
":ref:`overview-manual/concepts:package feeds`", and
":ref:`overview-manual/concepts:application development sdk`" sections all in the
Yocto Project Overview and Concepts Manual.
:term:`DEPLOY_DIR_DEB`
Points to the area that the OpenEmbedded build system uses to place
Debian packages that are ready to be used outside of the build
system. This variable applies only when :term:`PACKAGE_CLASSES` contains
":ref:`ref-classes-package_deb`".
The BitBake configuration file initially defines the
:term:`DEPLOY_DIR_DEB` variable as a sub-folder of
:term:`DEPLOY_DIR`::
DEPLOY_DIR_DEB = "${DEPLOY_DIR}/deb"
The :ref:`ref-classes-package_deb` class uses the
:term:`DEPLOY_DIR_DEB` variable to make sure the
:ref:`ref-tasks-package_write_deb` task
writes Debian packages into the appropriate folder. For more
information on how packaging works, see the
":ref:`overview-manual/concepts:package feeds`" section
in the Yocto Project Overview and Concepts Manual.
:term:`DEPLOY_DIR_IMAGE`
Points to the area that the OpenEmbedded build system uses to place
images and other associated output files that are ready to be
deployed onto the target machine. The directory is machine-specific
as it contains the ``${MACHINE}`` name. By default, this directory
resides within the :term:`Build Directory` as
``${DEPLOY_DIR}/images/${MACHINE}/``.
It must not be used directly in recipes when deploying files. Instead,
it's only useful when a recipe needs to "read" a file already deployed
by a dependency. So, it should be filled with the contents of
:term:`DEPLOYDIR` by the :ref:`ref-classes-deploy` class or with the
contents of :term:`IMGDEPLOYDIR` by the :ref:`ref-classes-image` class.
For more information on the structure of the :term:`Build Directory`, see
":ref:`ref-manual/structure:the build directory --- \`\`build/\`\``" section.
For more detail on the contents of the ``deploy`` directory, see the
":ref:`overview-manual/concepts:images`" and
":ref:`overview-manual/concepts:application development sdk`" sections both in
the Yocto Project Overview and Concepts Manual.
:term:`DEPLOY_DIR_IPK`
Points to the area that the OpenEmbedded build system uses to place
IPK packages that are ready to be used outside of the build system.
This variable applies only when :term:`PACKAGE_CLASSES` contains
":ref:`ref-classes-package_ipk`".
The BitBake configuration file initially defines this variable as a
sub-folder of :term:`DEPLOY_DIR`::
DEPLOY_DIR_IPK = "${DEPLOY_DIR}/ipk"
The :ref:`ref-classes-package_ipk` class uses the :term:`DEPLOY_DIR_IPK`
variable to make sure the :ref:`ref-tasks-package_write_ipk` task
writes IPK packages into the appropriate folder. For more information
on how packaging works, see the
":ref:`overview-manual/concepts:package feeds`" section
in the Yocto Project Overview and Concepts Manual.
:term:`DEPLOY_DIR_RPM`
Points to the area that the OpenEmbedded build system uses to place
RPM packages that are ready to be used outside of the build system.
This variable applies only when :term:`PACKAGE_CLASSES` contains
":ref:`ref-classes-package_rpm`".
The BitBake configuration file initially defines this variable as a
sub-folder of :term:`DEPLOY_DIR`::
DEPLOY_DIR_RPM = "${DEPLOY_DIR}/rpm"
The :ref:`ref-classes-package_rpm` class uses the
:term:`DEPLOY_DIR_RPM` variable to make sure the
:ref:`ref-tasks-package_write_rpm` task
writes RPM packages into the appropriate folder. For more information
on how packaging works, see the
":ref:`overview-manual/concepts:package feeds`" section
in the Yocto Project Overview and Concepts Manual.
:term:`DEPLOY_DIR_TAR`
Points to the area that the OpenEmbedded build system uses to place
tarballs that are ready to be used outside of the build system. This
variable applies only when :term:`PACKAGE_CLASSES` contains
":ref:`ref-classes-package_tar`".
The BitBake configuration file initially defines this variable as a
sub-folder of :term:`DEPLOY_DIR`::
DEPLOY_DIR_TAR = "${DEPLOY_DIR}/tar"
The :ref:`ref-classes-package_tar` class uses the
:term:`DEPLOY_DIR_TAR` variable to make sure the
:ref:`ref-tasks-package_write_tar` task
writes TAR packages into the appropriate folder. For more information
on how packaging works, see the
":ref:`overview-manual/concepts:package feeds`" section
in the Yocto Project Overview and Concepts Manual.
:term:`DEPLOYDIR`
When inheriting the :ref:`ref-classes-deploy` class, the
:term:`DEPLOYDIR` points to a temporary work area for deployed files that
is set in the :ref:`ref-classes-deploy` class as follows::
DEPLOYDIR = "${WORKDIR}/deploy-${PN}"
Recipes inheriting the :ref:`ref-classes-deploy` class should copy files to be
deployed into :term:`DEPLOYDIR`, and the class will take care of copying
them into :term:`DEPLOY_DIR_IMAGE`
afterwards.
:term:`DESCRIPTION`
The package description used by package managers. If not set,
:term:`DESCRIPTION` takes the value of the :term:`SUMMARY`
variable.
:term:`DEV_PKG_DEPENDENCY`
Provides an easy way for recipes to disable or adjust the runtime
dependency (:term:`RDEPENDS`) of the ``${PN}-dev`` package on the main
(``${PN}``) package, particularly where the main package may be empty.
:term:`DISABLE_STATIC`
Used in order to disable static linking by default (in order to save
space, since static libraries are often unused in embedded systems.)
The default value is " --disable-static", however it can be set to ""
in order to enable static linking if desired. Certain recipes do this
individually, and also there is a
``meta/conf/distro/include/no-static-libs.inc`` include file that
disables static linking for a number of recipes. Some software
packages or build tools (such as CMake) have explicit support for
enabling / disabling static linking, and in those cases
:term:`DISABLE_STATIC` is not used.
:term:`DISTRO`
The short name of the distribution. For information on the long name
of the distribution, see the :term:`DISTRO_NAME`
variable.
The :term:`DISTRO` variable corresponds to a distribution configuration
file whose root name is the same as the variable's argument and whose
filename extension is ``.conf``. For example, the distribution
configuration file for the Poky distribution is named ``poky.conf``
and resides in the ``meta-poky/conf/distro`` directory of the
:term:`Source Directory`.
Within that ``poky.conf`` file, the :term:`DISTRO` variable is set as
follows::
DISTRO = "poky"
Distribution configuration files are located in a ``conf/distro``
directory within the :term:`Metadata` that contains the
distribution configuration. The value for :term:`DISTRO` must not contain
spaces, and is typically all lower-case.
.. note::
If the :term:`DISTRO` variable is blank, a set of default configurations
are used, which are specified within
``meta/conf/distro/defaultsetup.conf`` also in the Source Directory.
:term:`DISTRO_CODENAME`
Specifies a codename for the distribution being built.
:term:`DISTRO_EXTRA_RDEPENDS`
Specifies a list of distro-specific packages to add to all images.
This variable takes effect through ``packagegroup-base`` so the
variable only really applies to the more full-featured images that
include ``packagegroup-base``. You can use this variable to keep
distro policy out of generic images. As with all other distro
variables, you set this variable in the distro ``.conf`` file.
:term:`DISTRO_EXTRA_RRECOMMENDS`
Specifies a list of distro-specific packages to add to all images if
the packages exist. The packages might not exist or be empty (e.g.
kernel modules). The list of packages are automatically installed but
you can remove them.
:term:`DISTRO_FEATURES`
The software support you want in your distribution for various
features. You define your distribution features in the distribution
configuration file.
In most cases, the presence or absence of a feature in
:term:`DISTRO_FEATURES` is translated to the appropriate option supplied
to the configure script during the
:ref:`ref-tasks-configure` task for recipes that
optionally support the feature. For example, specifying "x11" in
:term:`DISTRO_FEATURES`, causes every piece of software built for the
target that can optionally support X11 to have its X11 support
enabled.
.. note::
Just enabling :term:`DISTRO_FEATURES` alone doesn't
enable feature support for packages. Mechanisms such as making
:term:`PACKAGECONFIG` track :term:`DISTRO_FEATURES` are used
to enable/disable package features.
Two more examples are Bluetooth and NFS support. For a more complete
list of features that ships with the Yocto Project and that you can
provide with this variable, see the ":ref:`ref-features-distro`" section.
:term:`DISTRO_FEATURES_BACKFILL`
Features to be added to :term:`DISTRO_FEATURES` if not also present in
:term:`DISTRO_FEATURES_BACKFILL_CONSIDERED`.
This variable is set in the ``meta/conf/bitbake.conf`` file. It is
not intended to be user-configurable. It is best to just reference
the variable to see which distro features are being backfilled for
all distro configurations. See the ":ref:`ref-features-backfill`" section
for more information.
:term:`DISTRO_FEATURES_BACKFILL_CONSIDERED`
Features from :term:`DISTRO_FEATURES_BACKFILL` that should not be
backfilled (i.e. added to :term:`DISTRO_FEATURES`) during the build. See
the ":ref:`ref-features-backfill`" section for more information.
:term:`DISTRO_FEATURES_DEFAULT`
A convenience variable that gives you the default list of distro
features with the exception of any features specific to the C library
(``libc``).
When creating a custom distribution, you might find it useful to be
able to reuse the default
:term:`DISTRO_FEATURES` options without the
need to write out the full set. Here is an example that uses
:term:`DISTRO_FEATURES_DEFAULT` from a custom distro configuration file::
DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT} myfeature"
:term:`DISTRO_FEATURES_FILTER_NATIVE`
Specifies a list of features that if present in the target
:term:`DISTRO_FEATURES` value should be
included in :term:`DISTRO_FEATURES` when building native recipes. This
variable is used in addition to the features filtered using the
:term:`DISTRO_FEATURES_NATIVE`
variable.
:term:`DISTRO_FEATURES_FILTER_NATIVESDK`
Specifies a list of features that if present in the target
:term:`DISTRO_FEATURES` value should be included in
:term:`DISTRO_FEATURES` when building :ref:`ref-classes-nativesdk`
recipes. This variable is used in addition to the features filtered using
the :term:`DISTRO_FEATURES_NATIVESDK` variable.
:term:`DISTRO_FEATURES_NATIVE`
Specifies a list of features that should be included in
:term:`DISTRO_FEATURES` when building native
recipes. This variable is used in addition to the features filtered
using the
:term:`DISTRO_FEATURES_FILTER_NATIVE`
variable.
:term:`DISTRO_FEATURES_NATIVESDK`
Specifies a list of features that should be included in
:term:`DISTRO_FEATURES` when building
:ref:`ref-classes-nativesdk` recipes. This variable is used
in addition to the features filtered using the
:term:`DISTRO_FEATURES_FILTER_NATIVESDK` variable.
:term:`DISTRO_NAME`
The long name of the distribution. For information on the short name
of the distribution, see the :term:`DISTRO` variable.
The :term:`DISTRO_NAME` variable corresponds to a distribution
configuration file whose root name is the same as the variable's
argument and whose filename extension is ``.conf``. For example, the
distribution configuration file for the Poky distribution is named
``poky.conf`` and resides in the ``meta-poky/conf/distro`` directory
of the :term:`Source Directory`.
Within that ``poky.conf`` file, the :term:`DISTRO_NAME` variable is set
as follows::
DISTRO_NAME = "Poky (Yocto Project Reference Distro)"
Distribution configuration files are located in a ``conf/distro``
directory within the :term:`Metadata` that contains the
distribution configuration.
.. note::
If the :term:`DISTRO_NAME` variable is blank, a set of default
configurations are used, which are specified within
``meta/conf/distro/defaultsetup.conf`` also in the Source Directory.
:term:`DISTRO_VERSION`
The version of the distribution.
:term:`DISTROOVERRIDES`
A colon-separated list of overrides specific to the current
distribution. By default, this list includes the value of
:term:`DISTRO`.
You can extend :term:`DISTROOVERRIDES` to add extra overrides that should
apply to the distribution.
The underlying mechanism behind :term:`DISTROOVERRIDES` is simply that it
is included in the default value of
:term:`OVERRIDES`.
:term:`DL_DIR`
The central download directory used by the build process to store
downloads. By default, :term:`DL_DIR` gets files suitable for mirroring
for everything except Git repositories. If you want tarballs of Git
repositories, use the
:term:`BB_GENERATE_MIRROR_TARBALLS`
variable.
You can set this directory by defining the :term:`DL_DIR` variable in the
``conf/local.conf`` file. This directory is self-maintaining and you
should not have to touch it. By default, the directory is
``downloads`` in the :term:`Build Directory`::
#DL_DIR ?= "${TOPDIR}/downloads"
To specify a different download directory,
simply remove the comment from the line and provide your directory.
During a first build, the system downloads many different source code
tarballs from various upstream projects. Downloading can take a
while, particularly if your network connection is slow. Tarballs are
all stored in the directory defined by :term:`DL_DIR` and the build
system looks there first to find source tarballs.
.. note::
When wiping and rebuilding, you can preserve this directory to
speed up this part of subsequent builds.
You can safely share this directory between multiple builds on the
same development machine. For additional information on how the build
process gets source files when working behind a firewall or proxy
server, see this specific question in the ":doc:`faq`"
chapter. You can also refer to the
":yocto_wiki:`Working Behind a Network Proxy </Working_Behind_a_Network_Proxy>`"
Wiki page.
:term:`DOC_COMPRESS`
When inheriting the :ref:`ref-classes-compress_doc`
class, this variable sets the compression policy used when the
OpenEmbedded build system compresses man pages and info pages. By
default, the compression method used is gz (gzip). Other policies
available are xz and bz2.
For information on policies and on how to use this variable, see the
comments in the ``meta/classes-recipe/compress_doc.bbclass`` file.
:term:`EFI_PROVIDER`
When building bootable images (i.e. where ``hddimg``, ``iso``, or
``wic.vmdk`` is in :term:`IMAGE_FSTYPES`), the
:term:`EFI_PROVIDER` variable specifies the EFI bootloader to use. The
default is "grub-efi", but "systemd-boot" can be used instead.
See the :ref:`ref-classes-systemd-boot` and :ref:`ref-classes-image-live`
classes for more information.
:term:`ENABLE_BINARY_LOCALE_GENERATION`
Variable that controls which locales for ``glibc`` are generated
during the build (useful if the target device has 64Mbytes of RAM or
less).
:term:`ERR_REPORT_DIR`
When used with the :ref:`ref-classes-report-error` class, specifies the
path used for storing the debug files created by the :ref:`error reporting
tool <dev-manual/error-reporting-tool:using the error reporting tool>`,
which allows you to submit build errors you encounter to a central
database. By default, the value of this variable is
``${``\ :term:`LOG_DIR`\ ``}/error-report``.
You can set :term:`ERR_REPORT_DIR` to the path you want the error
reporting tool to store the debug files as follows in your
``local.conf`` file::
ERR_REPORT_DIR = "path"
:term:`ERROR_QA`
Specifies the quality assurance checks whose failures are reported as
errors by the OpenEmbedded build system. You set this variable in
your distribution configuration file. For a list of the checks you
can control with this variable, see the
":ref:`ref-classes-insane`" section.
:term:`ESDK_CLASS_INHERIT_DISABLE`
A list of classes to remove from the :term:`INHERIT`
value globally within the extensible SDK configuration. The
:ref:`populate-sdk-ext <ref-classes-populate-sdk-*>` class sets the
default value::
ESDK_CLASS_INHERIT_DISABLE ?= "buildhistory icecc"
Some classes are not generally applicable within the extensible SDK
context. You can use this variable to disable those classes.
For additional information on how to customize the extensible SDK's
configuration, see the
":ref:`sdk-manual/appendix-customizing:configuring the extensible sdk`"
section in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual.
:term:`ESDK_LOCALCONF_ALLOW`
A list of variables allowed through from the OpenEmbedded build
system configuration into the extensible SDK configuration. By
default, the list of variables is empty and is set in the
:ref:`populate-sdk-ext <ref-classes-populate-sdk-*>` class.
This list overrides the variables specified using the
:term:`ESDK_LOCALCONF_REMOVE` variable as well as
other variables automatically added due to the "/" character
being found at the start of the
value, which is usually indicative of being a path and thus might not
be valid on the system where the SDK is installed.
For additional information on how to customize the extensible SDK's
configuration, see the
":ref:`sdk-manual/appendix-customizing:configuring the extensible sdk`"
section in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual.
:term:`ESDK_LOCALCONF_REMOVE`
A list of variables not allowed through from the OpenEmbedded build
system configuration into the extensible SDK configuration. Usually,
these are variables that are specific to the machine on which the
build system is running and thus would be potentially problematic
within the extensible SDK.
By default, :term:`ESDK_LOCALCONF_REMOVE` is set in the
:ref:`populate-sdk-ext <ref-classes-populate-sdk-*>` class and
excludes the following variables:
- :term:`CONF_VERSION`
- :term:`BB_NUMBER_THREADS`
- :term:`BB_NUMBER_PARSE_THREADS`
- :term:`PARALLEL_MAKE`
- :term:`PRSERV_HOST`
- :term:`SSTATE_MIRRORS` :term:`DL_DIR`
- :term:`SSTATE_DIR` :term:`TMPDIR`
- :term:`BB_SERVER_TIMEOUT`
For additional information on how to customize the extensible SDK's
configuration, see the
":ref:`sdk-manual/appendix-customizing:configuring the extensible sdk`"
section in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual.
:term:`EXCLUDE_FROM_SHLIBS`
Triggers the OpenEmbedded build system's shared libraries resolver to
exclude an entire package when scanning for shared libraries.
.. note::
The shared libraries resolver's functionality results in part from
the internal function ``package_do_shlibs``, which is part of the
:ref:`ref-tasks-package` task. You should be aware that the shared
libraries resolver might implicitly define some dependencies between
packages.
The :term:`EXCLUDE_FROM_SHLIBS` variable is similar to the
:term:`PRIVATE_LIBS` variable, which excludes a
package's particular libraries only and not the whole package.
Use the :term:`EXCLUDE_FROM_SHLIBS` variable by setting it to "1" for a
particular package::
EXCLUDE_FROM_SHLIBS = "1"
:term:`EXCLUDE_FROM_WORLD`
Directs BitBake to exclude a recipe from world builds (i.e.
``bitbake world``). During world builds, BitBake locates, parses and
builds all recipes found in every layer exposed in the
``bblayers.conf`` configuration file.
To exclude a recipe from a world build using this variable, set the
variable to "1" in the recipe.
.. note::
Recipes added to :term:`EXCLUDE_FROM_WORLD` may still be built during a
world build in order to satisfy dependencies of other recipes. Adding
a recipe to :term:`EXCLUDE_FROM_WORLD` only ensures that the recipe is not
explicitly added to the list of build targets in a world build.
:term:`EXTENDPE`
Used with file and pathnames to create a prefix for a recipe's
version based on the recipe's :term:`PE` value. If :term:`PE`
is set and greater than zero for a recipe, :term:`EXTENDPE` becomes that
value (e.g if :term:`PE` is equal to "1" then :term:`EXTENDPE` becomes "1").
If a recipe's :term:`PE` is not set (the default) or is equal to zero,
:term:`EXTENDPE` becomes "".
See the :term:`STAMP` variable for an example.
:term:`EXTENDPKGV`
The full package version specification as it appears on the final
packages produced by a recipe. The variable's value is normally used
to fix a runtime dependency to the exact same version of another
package in the same recipe::
RDEPENDS:${PN}-additional-module = "${PN} (= ${EXTENDPKGV})"
The dependency relationships are intended to force the package
manager to upgrade these types of packages in lock-step.
:term:`EXTERNAL_KERNEL_TOOLS`
When set, the :term:`EXTERNAL_KERNEL_TOOLS` variable indicates that these
tools are not in the source tree.
When kernel tools are available in the tree, they are preferred over
any externally installed tools. Setting the :term:`EXTERNAL_KERNEL_TOOLS`
variable tells the OpenEmbedded build system to prefer the installed
external tools. See the :ref:`ref-classes-kernel-yocto` class in
``meta/classes-recipe`` to see how the variable is used.
:term:`EXTERNAL_TOOLCHAIN`
When you intend to use an
:ref:`external toolchain <dev-manual/external-toolchain:optionally using an external toolchain>`,
this variable allows to specify the directory where this toolchain was
installed.
:term:`EXTERNALSRC`
When inheriting the :ref:`ref-classes-externalsrc`
class, this variable points to the source tree, which is outside of
the OpenEmbedded build system. When set, this variable sets the
:term:`S` variable, which is what the OpenEmbedded build
system uses to locate unpacked recipe source code.
See the ":ref:`ref-classes-externalsrc`" section for details. You
can also find information on how to use this variable in the
":ref:`dev-manual/building:building software from an external source`"
section in the Yocto Project Development Tasks Manual.
:term:`EXTERNALSRC_BUILD`
When inheriting the :ref:`ref-classes-externalsrc`
class, this variable points to the directory in which the recipe's
source code is built, which is outside of the OpenEmbedded build
system. When set, this variable sets the :term:`B` variable,
which is what the OpenEmbedded build system uses to locate the
:term:`Build Directory`.
See the ":ref:`ref-classes-externalsrc`" section for details. You
can also find information on how to use this variable in the
":ref:`dev-manual/building:building software from an external source`"
section in the Yocto Project Development Tasks Manual.
:term:`EXTRA_AUTORECONF`
For recipes inheriting the :ref:`ref-classes-autotools`
class, you can use :term:`EXTRA_AUTORECONF` to specify extra options to
pass to the ``autoreconf`` command that is executed during the
:ref:`ref-tasks-configure` task.
The default value is "--exclude=autopoint".
:term:`EXTRA_IMAGE_FEATURES`
A list of additional features to include in an image. When listing
more than one feature, separate them with a space.
Typically, you configure this variable in your ``local.conf`` file,
which is found in the :term:`Build Directory`. Although you can use this
variable from within a recipe, best practices dictate that you do not.
.. note::
To enable primary features from within the image recipe, use the
:term:`IMAGE_FEATURES` variable.
Here are some examples of features you can add:
- "dbg-pkgs" --- adds -dbg packages for all installed packages including
symbol information for debugging and profiling.
- "debug-tweaks" --- makes an image suitable for debugging. For example, allows root logins without passwords and
enables post-installation logging. See the 'allow-empty-password' and
'post-install-logging' features in the ":ref:`ref-features-image`"
section for more information.
- "dev-pkgs" --- adds -dev packages for all installed packages. This is
useful if you want to develop against the libraries in the image.
- "read-only-rootfs" --- creates an image whose root filesystem is
read-only. See the
":ref:`dev-manual/read-only-rootfs:creating a read-only root filesystem`"
section in the Yocto Project Development Tasks Manual for more
information
- "tools-debug" --- adds debugging tools such as gdb and strace.
- "tools-sdk" --- adds development tools such as gcc, make,
pkgconfig and so forth.
- "tools-testapps" --- adds useful testing tools
such as ts_print, aplay, arecord and so forth.
For a complete list of image features that ships with the Yocto
Project, see the ":ref:`ref-features-image`" section.
For an example that shows how to customize your image by using this
variable, see the ":ref:`dev-manual/customizing-images:customizing images using custom \`\`image_features\`\` and \`\`extra_image_features\`\``"
section in the Yocto Project Development Tasks Manual.
:term:`EXTRA_IMAGECMD`
Specifies additional options for the image creation command that has
been specified in :term:`IMAGE_CMD`. When setting
this variable, use an override for the associated image type. Here is
an example::
EXTRA_IMAGECMD:ext3 ?= "-i 4096"
:term:`EXTRA_IMAGEDEPENDS`
A list of recipes to build that do not provide packages for
installing into the root filesystem.
Sometimes a recipe is required to build the final image but is not
needed in the root filesystem. You can use the :term:`EXTRA_IMAGEDEPENDS`
variable to list these recipes and thus specify the dependencies. A
typical example is a required bootloader in a machine configuration.
.. note::
To add packages to the root filesystem, see the various
:term:`RDEPENDS` and :term:`RRECOMMENDS` variables.
:term:`EXTRA_OECMAKE`
Additional `CMake <https://cmake.org/overview/>`__ options. See the
:ref:`ref-classes-cmake` class for additional information.
:term:`EXTRA_OECONF`
Additional ``configure`` script options. See
:term:`PACKAGECONFIG_CONFARGS` for
additional information on passing configure script options.
:term:`EXTRA_OEMAKE`
Additional GNU ``make`` options.
Because the :term:`EXTRA_OEMAKE` defaults to "", you need to set the
variable to specify any required GNU options.
:term:`PARALLEL_MAKE` and
:term:`PARALLEL_MAKEINST` also make use of
:term:`EXTRA_OEMAKE` to pass the required flags.
:term:`EXTRA_OESCONS`
When inheriting the :ref:`ref-classes-scons` class, this
variable specifies additional configuration options you want to pass
to the ``scons`` command line.
:term:`EXTRA_USERS_PARAMS`
When inheriting the :ref:`ref-classes-extrausers`
class, this variable provides image level user and group operations.
This is a more global method of providing user and group
configuration as compared to using the
:ref:`ref-classes-useradd` class, which ties user and
group configurations to a specific recipe.
The set list of commands you can configure using the
:term:`EXTRA_USERS_PARAMS` is shown in the
:ref:`ref-classes-extrausers` class. These commands map to the normal
Unix commands of the same names::
# EXTRA_USERS_PARAMS = "\
# useradd -p '' tester; \
# groupadd developers; \
# userdel nobody; \
# groupdel -g video; \
# groupmod -g 1020 developers; \
# usermod -s /bin/sh tester; \
# "
Hardcoded passwords are supported via the ``-p`` parameters for
``useradd`` or ``usermod``, but only hashed.
Here is an example that adds two users named "tester-jim" and "tester-sue" and assigns
passwords. First on host, create the (escaped) password hash::
printf "%q" $(mkpasswd -m sha256crypt tester01)
The resulting hash is set to a variable and used in ``useradd`` command parameters::
inherit extrausers
PASSWD = "\$X\$ABC123\$A-Long-Hash"
EXTRA_USERS_PARAMS = "\
useradd -p '${PASSWD}' tester-jim; \
useradd -p '${PASSWD}' tester-sue; \
"
Finally, here is an example that sets the root password::
inherit extrausers
EXTRA_USERS_PARAMS = "\
usermod -p '${PASSWD}' root; \
"
.. note::
From a security perspective, hardcoding a default password is not
generally a good idea or even legal in some jurisdictions. It is
recommended that you do not do this if you are building a production
image.
Additionally there is a special ``passwd-expire`` command that will
cause the password for a user to be expired and thus force changing it
on first login, for example::
EXTRA_USERS_PARAMS += " useradd myuser; passwd-expire myuser;"
.. note::
At present, ``passwd-expire`` may only work for remote logins when
using OpenSSH and not dropbear as an SSH server.
:term:`EXTRANATIVEPATH`
A list of subdirectories of
``${``\ :term:`STAGING_BINDIR_NATIVE`\ ``}``
added to the beginning of the environment variable ``PATH``. As an
example, the following prepends
"${STAGING_BINDIR_NATIVE}/foo:${STAGING_BINDIR_NATIVE}/bar:" to
``PATH``::
EXTRANATIVEPATH = "foo bar"
:term:`FAKEROOT`
See :term:`bitbake:FAKEROOT` in the BitBake manual.
:term:`FAKEROOTBASEENV`
See :term:`bitbake:FAKEROOTBASEENV` in the BitBake manual.
:term:`FAKEROOTCMD`
See :term:`bitbake:FAKEROOTCMD` in the BitBake manual.
:term:`FAKEROOTDIRS`
See :term:`bitbake:FAKEROOTDIRS` in the BitBake manual.
:term:`FAKEROOTENV`
See :term:`bitbake:FAKEROOTENV` in the BitBake manual.
:term:`FAKEROOTNOENV`
See :term:`bitbake:FAKEROOTNOENV` in the BitBake manual.
:term:`FEATURE_PACKAGES`
Defines one or more packages to include in an image when a specific
item is included in :term:`IMAGE_FEATURES`.
When setting the value, :term:`FEATURE_PACKAGES` should have the name of
the feature item as an override. Here is an example::
FEATURE_PACKAGES_widget = "package1 package2"
In this example, if "widget" were added to :term:`IMAGE_FEATURES`,
package1 and package2 would be included in the image.
.. note::
Packages installed by features defined through :term:`FEATURE_PACKAGES`
are often package groups. While similarly named, you should not
confuse the :term:`FEATURE_PACKAGES` variable with package groups, which
are discussed elsewhere in the documentation.
:term:`FEED_DEPLOYDIR_BASE_URI`
Points to the base URL of the server and location within the
document-root that provides the metadata and packages required by
OPKG to support runtime package management of IPK packages. You set
this variable in your ``local.conf`` file.
Consider the following example::
FEED_DEPLOYDIR_BASE_URI = "http://192.168.7.1/BOARD-dir"
This example assumes you are serving
your packages over HTTP and your databases are located in a directory
named ``BOARD-dir``, which is underneath your HTTP server's
document-root. In this case, the OpenEmbedded build system generates
a set of configuration files for you in your target that work with
the feed.
:term:`FETCHCMD`
See :term:`bitbake:FETCHCMD` in the BitBake manual.
:term:`FILE`
See :term:`bitbake:FILE` in the BitBake manual.
:term:`FILES`
The list of files and directories that are placed in a package. The
:term:`PACKAGES` variable lists the packages
generated by a recipe.
To use the :term:`FILES` variable, provide a package name override that
identifies the resulting package. Then, provide a space-separated
list of files or paths that identify the files you want included as
part of the resulting package. Here is an example::
FILES:${PN} += "${bindir}/mydir1 ${bindir}/mydir2/myfile"
.. note::
- When specifying files or paths, you can pattern match using
Python's
`glob <https://docs.python.org/3/library/glob.html>`__
syntax. For details on the syntax, see the documentation by
following the previous link.
- When specifying paths as part of the :term:`FILES` variable, it is
good practice to use appropriate path variables. For example,
use ``${sysconfdir}`` rather than ``/etc``, or ``${bindir}``
rather than ``/usr/bin``. You can find a list of these
variables at the top of the ``meta/conf/bitbake.conf`` file in
the :term:`Source Directory`. You will also
find the default values of the various ``FILES:*`` variables in
this file.
If some of the files you provide with the :term:`FILES` variable are
editable and you know they should not be overwritten during the
package update process by the Package Management System (PMS), you
can identify these files so that the PMS will not overwrite them. See
the :term:`CONFFILES` variable for information on
how to identify these files to the PMS.
:term:`FILES_SOLIBSDEV`
Defines the file specification to match
:term:`SOLIBSDEV`. In other words,
:term:`FILES_SOLIBSDEV` defines the full path name of the development
symbolic link (symlink) for shared libraries on the target platform.
The following statement from the ``bitbake.conf`` shows how it is
set::
FILES_SOLIBSDEV ?= "${base_libdir}/lib*${SOLIBSDEV} ${libdir}/lib*${SOLIBSDEV}"
:term:`FILESEXTRAPATHS`
Extends the search path the OpenEmbedded build system uses when
looking for files and patches as it processes recipes and append
files. The default directories BitBake uses when it processes recipes
are initially defined by the :term:`FILESPATH`
variable. You can extend :term:`FILESPATH` variable by using
:term:`FILESEXTRAPATHS`.
Best practices dictate that you accomplish this by using
:term:`FILESEXTRAPATHS` from within a ``.bbappend`` file and that you
prepend paths as follows::
FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
In the above example, the build system first
looks for files in a directory that has the same name as the
corresponding append file.
.. note::
When extending :term:`FILESEXTRAPATHS`, be sure to use the immediate
expansion (``:=``) operator. Immediate expansion makes sure that
BitBake evaluates :term:`THISDIR` at the time the
directive is encountered rather than at some later time when
expansion might result in a directory that does not contain the
files you need.
Also, include the trailing separating colon character if you are
prepending. The trailing colon character is necessary because you
are directing BitBake to extend the path by prepending directories
to the search path.
Here is another common use::
FILESEXTRAPATHS:prepend := "${THISDIR}/files:"
In this example, the build system extends the
:term:`FILESPATH` variable to include a directory named ``files`` that is
in the same directory as the corresponding append file.
This next example specifically adds three paths::
FILESEXTRAPATHS:prepend := "path_1:path_2:path_3:"
A final example shows how you can extend the search path and include
a :term:`MACHINE`-specific override, which is useful
in a BSP layer::
FILESEXTRAPATHS:prepend:intel-x86-common := "${THISDIR}/${PN}:"
The previous statement appears in the
``linux-yocto-dev.bbappend`` file, which is found in the
:ref:`overview-manual/development-environment:yocto project source repositories` in
``meta-intel/common/recipes-kernel/linux``. Here, the machine
override is a special :term:`PACKAGE_ARCH`
definition for multiple ``meta-intel`` machines.
.. note::
For a layer that supports a single BSP, the override could just be
the value of :term:`MACHINE`.
By prepending paths in ``.bbappend`` files, you allow multiple append
files that reside in different layers but are used for the same
recipe to correctly extend the path.
:term:`FILESOVERRIDES`
A subset of :term:`OVERRIDES` used by the
OpenEmbedded build system for creating
:term:`FILESPATH`. The :term:`FILESOVERRIDES` variable
uses overrides to automatically extend the
:term:`FILESPATH` variable. For an example of how
that works, see the :term:`FILESPATH` variable
description. Additionally, you find more information on how overrides
are handled in the
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:conditional syntax (overrides)`"
section of the BitBake User Manual.
By default, the :term:`FILESOVERRIDES` variable is defined as::
FILESOVERRIDES = "${TRANSLATED_TARGET_ARCH}:${MACHINEOVERRIDES}:${DISTROOVERRIDES}"
.. note::
Do not hand-edit the :term:`FILESOVERRIDES` variable. The values match up
with expected overrides and are used in an expected manner by the
build system.
:term:`FILESPATH`
The default set of directories the OpenEmbedded build system uses
when searching for patches and files.
During the build process, BitBake searches each directory in
:term:`FILESPATH` in the specified order when looking for files and
patches specified by each ``file://`` URI in a recipe's
:term:`SRC_URI` statements.
The default value for the :term:`FILESPATH` variable is defined in the
:ref:`ref-classes-base` class found in ``meta/classes-global`` in the
:term:`Source Directory`::
FILESPATH = "${@base_set_filespath(["${FILE_DIRNAME}/${BP}", \
"${FILE_DIRNAME}/${BPN}", "${FILE_DIRNAME}/files"], d)}"
The
:term:`FILESPATH` variable is automatically extended using the overrides
from the :term:`FILESOVERRIDES` variable.
.. note::
- Do not hand-edit the :term:`FILESPATH` variable. If you want the
build system to look in directories other than the defaults,
extend the :term:`FILESPATH` variable by using the
:term:`FILESEXTRAPATHS` variable.
- Be aware that the default :term:`FILESPATH` directories do not map
to directories in custom layers where append files
(``.bbappend``) are used. If you want the build system to find
patches or files that reside with your append files, you need
to extend the :term:`FILESPATH` variable by using the
:term:`FILESEXTRAPATHS` variable.
You can take advantage of this searching behavior in useful ways. For
example, consider a case where there is the following directory structure
for general and machine-specific configurations::
files/defconfig
files/MACHINEA/defconfig
files/MACHINEB/defconfig
Also in the example, the :term:`SRC_URI` statement contains
"file://defconfig". Given this scenario, you can set
:term:`MACHINE` to "MACHINEA" and cause the build
system to use files from ``files/MACHINEA``. Set :term:`MACHINE` to
"MACHINEB" and the build system uses files from ``files/MACHINEB``.
Finally, for any machine other than "MACHINEA" and "MACHINEB", the
build system uses files from ``files/defconfig``.
You can find out more about the patching process in the
":ref:`overview-manual/concepts:patching`" section
in the Yocto Project Overview and Concepts Manual and the
":ref:`dev-manual/new-recipe:patching code`" section in
the Yocto Project Development Tasks Manual. See the
:ref:`ref-tasks-patch` task as well.
:term:`FILESYSTEM_PERMS_TABLES`
Allows you to define your own file permissions settings table as part
of your configuration for the packaging process. For example, suppose
you need a consistent set of custom permissions for a set of groups
and users across an entire work project. It is best to do this in the
packages themselves but this is not always possible.
By default, the OpenEmbedded build system uses the ``fs-perms.txt``,
which is located in the ``meta/files`` folder in the :term:`Source Directory`.
If you create your own file
permissions setting table, you should place it in your layer or the
distro's layer.
You define the :term:`FILESYSTEM_PERMS_TABLES` variable in the
``conf/local.conf`` file, which is found in the :term:`Build Directory`,
to point to your custom ``fs-perms.txt``. You can specify more than a
single file permissions setting table. The paths you specify to these
files must be defined within the :term:`BBPATH` variable.
For guidance on how to create your own file permissions settings
table file, examine the existing ``fs-perms.txt``.
:term:`FIT_DESC`
Specifies the description string encoded into a fitImage. The default
value is set by the :ref:`ref-classes-kernel-fitimage`
class as follows::
FIT_DESC ?= "U-Boot fitImage for ${DISTRO_NAME}/${PV}/${MACHINE}"
:term:`FIT_GENERATE_KEYS`
Decides whether to generate the keys for signing fitImage if they
don't already exist. The keys are created in :term:`UBOOT_SIGN_KEYDIR`.
The default value is 0.
:term:`FIT_HASH_ALG`
Specifies the hash algorithm used in creating the FIT Image. For e.g. sha256.
:term:`FIT_KERNEL_COMP_ALG`
Compression algorithm to use for the kernel image inside the FIT Image.
At present, the only supported values are "gzip" (default) or "none"
If you set this variable to anything other than "none" you may also need
to set :term:`FIT_KERNEL_COMP_ALG_EXTENSION`.
:term:`FIT_KERNEL_COMP_ALG_EXTENSION`
File extension corresponding to :term:`FIT_KERNEL_COMP_ALG`. The default
value is ".gz".
:term:`FIT_KEY_GENRSA_ARGS`
Arguments to openssl genrsa for generating RSA private key for signing
fitImage. The default value is "-F4". i.e. the public exponent 65537 to
use.
:term:`FIT_KEY_REQ_ARGS`
Arguments to openssl req for generating certificate for signing fitImage.
The default value is "-batch -new". batch for non interactive mode
and new for generating new keys.
:term:`FIT_KEY_SIGN_PKCS`
Format for public key certificate used in signing fitImage.
The default value is "x509".
:term:`FIT_SIGN_ALG`
Specifies the signature algorithm used in creating the FIT Image.
For e.g. rsa2048.
:term:`FIT_PAD_ALG`
Specifies the padding algorithm used in creating the FIT Image.
The default value is "pkcs-1.5".
:term:`FIT_SIGN_INDIVIDUAL`
If set to "1", then the :ref:`ref-classes-kernel-fitimage`
class will sign the kernel, dtb and ramdisk images individually in addition
to signing the fitImage itself. This could be useful if you are
intending to verify signatures in another context than booting via
U-Boot.
:term:`FIT_SIGN_NUMBITS`
Size of private key in number of bits used in fitImage. The default
value is "2048".
:term:`FONT_EXTRA_RDEPENDS`
When inheriting the :ref:`ref-classes-fontcache` class,
this variable specifies the runtime dependencies for font packages.
By default, the :term:`FONT_EXTRA_RDEPENDS` is set to "fontconfig-utils".
:term:`FONT_PACKAGES`
When inheriting the :ref:`ref-classes-fontcache` class, this variable
identifies packages containing font files that need to be cached by
Fontconfig. By default, the :ref:`ref-classes-fontcache` class assumes
that fonts are in the recipe's main package (i.e.
``${``\ :term:`PN`\ ``}``). Use this variable if fonts you
need are in a package other than that main package.
:term:`FORCE_RO_REMOVE`
Forces the removal of the packages listed in ``ROOTFS_RO_UNNEEDED``
during the generation of the root filesystem.
Set the variable to "1" to force the removal of these packages.
:term:`FULL_OPTIMIZATION`
The options to pass in :term:`TARGET_CFLAGS` and :term:`CFLAGS` when
compiling an optimized system. This variable defaults to "-O2 -pipe
${DEBUG_FLAGS}".
:term:`GCCPIE`
Enables Position Independent Executables (PIE) within the GNU C
Compiler (GCC). Enabling PIE in the GCC makes Return Oriented
Programming (ROP) attacks much more difficult to execute.
By default the ``security_flags.inc`` file enables PIE by setting the
variable as follows::
GCCPIE ?= "--enable-default-pie"
:term:`GCCVERSION`
Specifies the default version of the GNU C Compiler (GCC) used for
compilation. By default, :term:`GCCVERSION` is set to "8.x" in the
``meta/conf/distro/include/tcmode-default.inc`` include file::
GCCVERSION ?= "8.%"
You can override this value by setting it in a
configuration file such as the ``local.conf``.
:term:`GDB`
The minimal command and arguments to run the GNU Debugger.
:term:`GIR_EXTRA_LIBS_PATH`
Allows to specify an extra search path for ``.so`` files
in GLib related recipes using GObject introspection,
and which do not compile without this setting.
See the ":ref:`dev-manual/gobject-introspection:enabling gobject introspection support`"
section for details.
:term:`GITDIR`
The directory in which a local copy of a Git repository is stored
when it is cloned.
:term:`GITHUB_BASE_URI`
When inheriting the :ref:`ref-classes-github-releases`
class, specifies the base URL for fetching releases for the github
project you wish to fetch sources from. The default value is as follows::
GITHUB_BASE_URI ?= "https://github.com/${BPN}/${BPN}/releases/"
:term:`GLIBC_GENERATE_LOCALES`
Specifies the list of GLIBC locales to generate should you not wish
to generate all LIBC locals, which can be time consuming.
.. note::
If you specifically remove the locale ``en_US.UTF-8``, you must set
:term:`IMAGE_LINGUAS` appropriately.
You can set :term:`GLIBC_GENERATE_LOCALES` in your ``local.conf`` file.
By default, all locales are generated::
GLIBC_GENERATE_LOCALES = "en_GB.UTF-8 en_US.UTF-8"
:term:`GROUPADD_PARAM`
When inheriting the :ref:`ref-classes-useradd` class,
this variable specifies for a package what parameters should be
passed to the ``groupadd`` command if you wish to add a group to the
system when the package is installed.
Here is an example from the ``dbus`` recipe::
GROUPADD_PARAM:${PN} = "-r netdev"
For information on the standard Linux shell command
``groupadd``, see https://linux.die.net/man/8/groupadd.
:term:`GROUPMEMS_PARAM`
When inheriting the :ref:`ref-classes-useradd` class,
this variable specifies for a package what parameters should be
passed to the ``groupmems`` command if you wish to modify the members
of a group when the package is installed.
For information on the standard Linux shell command ``groupmems``,
see https://linux.die.net/man/8/groupmems.
:term:`GRUB_GFXSERIAL`
Configures the GNU GRand Unified Bootloader (GRUB) to have graphics
and serial in the boot menu. Set this variable to "1" in your
``local.conf`` or distribution configuration file to enable graphics
and serial in the menu.
See the :ref:`ref-classes-grub-efi` class for more
information on how this variable is used.
:term:`GRUB_OPTS`
Additional options to add to the GNU GRand Unified Bootloader (GRUB)
configuration. Use a semi-colon character (``;``) to separate
multiple options.
The :term:`GRUB_OPTS` variable is optional. See the
:ref:`ref-classes-grub-efi` class for more information
on how this variable is used.
:term:`GRUB_TIMEOUT`
Specifies the timeout before executing the default ``LABEL`` in the
GNU GRand Unified Bootloader (GRUB).
The :term:`GRUB_TIMEOUT` variable is optional. See the
:ref:`ref-classes-grub-efi` class for more information
on how this variable is used.
:term:`GTKIMMODULES_PACKAGES`
When inheriting the :ref:`ref-classes-gtk-immodules-cache` class,
this variable specifies the packages that contain the GTK+ input
method modules being installed when the modules are in packages other
than the main package.
:term:`HGDIR`
See :term:`bitbake:HGDIR` in the BitBake manual.
:term:`HOMEPAGE`
Website where more information about the software the recipe is
building can be found.
:term:`HOST_ARCH`
The name of the target architecture, which is normally the same as
:term:`TARGET_ARCH`. The OpenEmbedded build system
supports many architectures. Here is an example list of architectures
supported. This list is by no means complete as the architecture is
configurable:
- arm
- i586
- x86_64
- powerpc
- powerpc64
- mips
- mipsel
:term:`HOST_CC_ARCH`
Specifies architecture-specific compiler flags that are passed to the
C compiler.
Default initialization for :term:`HOST_CC_ARCH` varies depending on what
is being built:
- :term:`TARGET_CC_ARCH` when building for the
target
- :term:`BUILD_CC_ARCH` when building for the build host (i.e.
``-native``)
- ``BUILDSDK_CC_ARCH`` when building for an SDK (i.e.
``nativesdk-``)
:term:`HOST_OS`
Specifies the name of the target operating system, which is normally
the same as the :term:`TARGET_OS`. The variable can
be set to "linux" for ``glibc``-based systems and to "linux-musl" for
``musl``. For ARM/EABI targets, there are also "linux-gnueabi" and
"linux-musleabi" values possible.
:term:`HOST_PREFIX`
Specifies the prefix for the cross-compile toolchain. :term:`HOST_PREFIX`
is normally the same as :term:`TARGET_PREFIX`.
:term:`HOST_SYS`
Specifies the system, including the architecture and the operating
system, for which the build is occurring in the context of the
current recipe.
The OpenEmbedded build system automatically sets this variable based
on :term:`HOST_ARCH`,
:term:`HOST_VENDOR`, and
:term:`HOST_OS` variables.
.. note::
You do not need to set the variable yourself.
Consider these two examples:
- Given a native recipe on a 32-bit x86 machine running Linux, the
value is "i686-linux".
- Given a recipe being built for a little-endian MIPS target running
Linux, the value might be "mipsel-linux".
:term:`HOST_VENDOR`
Specifies the name of the vendor. :term:`HOST_VENDOR` is normally the
same as :term:`TARGET_VENDOR`.
:term:`HOSTTOOLS`
A space-separated list (filter) of tools on the build host that
should be allowed to be called from within build tasks. Using this
filter helps reduce the possibility of host contamination. If a tool
specified in the value of :term:`HOSTTOOLS` is not found on the build
host, the OpenEmbedded build system produces an error and the build
is not started.
For additional information, see
:term:`HOSTTOOLS_NONFATAL`.
:term:`HOSTTOOLS_NONFATAL`
A space-separated list (filter) of tools on the build host that
should be allowed to be called from within build tasks. Using this
filter helps reduce the possibility of host contamination. Unlike
:term:`HOSTTOOLS`, the OpenEmbedded build system
does not produce an error if a tool specified in the value of
:term:`HOSTTOOLS_NONFATAL` is not found on the build host. Thus, you can
use :term:`HOSTTOOLS_NONFATAL` to filter optional host tools.
:term:`ICECC_CLASS_DISABLE`
Identifies user classes that you do not want the Icecream distributed
compile support to consider. This variable is used by the
:ref:`ref-classes-icecc` class. You set this variable in
your ``local.conf`` file.
When you list classes using this variable, the recipes inheriting
those classes will not benefit from distributed compilation across
remote hosts. Instead they will be built locally.
:term:`ICECC_DISABLED`
Disables or enables the ``icecc`` (Icecream) function. For more
information on this function and best practices for using this
variable, see the ":ref:`ref-classes-icecc`"
section.
Setting this variable to "1" in your ``local.conf`` disables the
function::
ICECC_DISABLED ??= "1"
To enable the function, set the variable as follows::
ICECC_DISABLED = ""
:term:`ICECC_ENV_EXEC`
Points to the ``icecc-create-env`` script that you provide. This
variable is used by the :ref:`ref-classes-icecc` class. You
set this variable in your ``local.conf`` file.
If you do not point to a script that you provide, the OpenEmbedded
build system uses the default script provided by the
:oe_git:`icecc-create-env_0.1.bb
</openembedded-core/tree/meta/recipes-devtools/icecc-create-env/icecc-create-env_0.1.bb>`
recipe, which is a modified version and not the one that comes with
``icecream``.
:term:`ICECC_PARALLEL_MAKE`
Extra options passed to the ``make`` command during the
:ref:`ref-tasks-compile` task that specify parallel
compilation. This variable usually takes the form of "-j x", where x
represents the maximum number of parallel threads ``make`` can run.
.. note::
The options passed affect builds on all enabled machines on the
network, which are machines running the ``iceccd`` daemon.
If your enabled machines support multiple cores, coming up with the
maximum number of parallel threads that gives you the best
performance could take some experimentation since machine speed,
network lag, available memory, and existing machine loads can all
affect build time. Consequently, unlike the
:term:`PARALLEL_MAKE` variable, there is no
rule-of-thumb for setting :term:`ICECC_PARALLEL_MAKE` to achieve optimal
performance.
If you do not set :term:`ICECC_PARALLEL_MAKE`, the build system does not
use it (i.e. the system does not detect and assign the number of
cores as is done with :term:`PARALLEL_MAKE`).
:term:`ICECC_PATH`
The location of the ``icecc`` binary. You can set this variable in
your ``local.conf`` file. If your ``local.conf`` file does not define
this variable, the :ref:`ref-classes-icecc` class attempts
to define it by locating ``icecc`` using ``which``.
:term:`ICECC_RECIPE_DISABLE`
Identifies user recipes that you do not want the Icecream distributed
compile support to consider. This variable is used by the
:ref:`ref-classes-icecc` class. You set this variable in
your ``local.conf`` file.
When you list recipes using this variable, you are excluding them
from distributed compilation across remote hosts. Instead they will
be built locally.
:term:`ICECC_RECIPE_ENABLE`
Identifies user recipes that use an empty
:term:`PARALLEL_MAKE` variable that you want to
force remote distributed compilation on using the Icecream
distributed compile support. This variable is used by the
:ref:`ref-classes-icecc` class. You set this variable in
your ``local.conf`` file.
:term:`IMAGE_BASENAME`
The base name of image output files. This variable defaults to the
recipe name (``${``\ :term:`PN`\ ``}``).
:term:`IMAGE_BOOT_FILES`
A space-separated list of files installed into the boot partition
when preparing an image using the Wic tool with the
``bootimg-partition`` source plugin. By default,
the files are
installed under the same name as the source files. To change the
installed name, separate it from the original name with a semi-colon
(;). Source files need to be located in
:term:`DEPLOY_DIR_IMAGE`. Here are two
examples::
IMAGE_BOOT_FILES = "u-boot.img uImage;kernel"
IMAGE_BOOT_FILES = "u-boot.${UBOOT_SUFFIX} ${KERNEL_IMAGETYPE}"
Alternatively, source files can be picked up using a glob pattern. In
this case, the destination file must have the same name as the base
name of the source file path. To install files into a directory
within the target location, pass its name after a semi-colon (;).
Here are two examples::
IMAGE_BOOT_FILES = "bcm2835-bootfiles/*"
IMAGE_BOOT_FILES = "bcm2835-bootfiles/*;boot/"
The first example
installs all files from ``${DEPLOY_DIR_IMAGE}/bcm2835-bootfiles``
into the root of the target partition. The second example installs
the same files into a ``boot`` directory within the target partition.
You can find information on how to use the Wic tool in the
":ref:`dev-manual/wic:creating partitioned images using wic`"
section of the Yocto Project Development Tasks Manual. Reference
material for Wic is located in the
":doc:`/ref-manual/kickstart`" chapter.
:term:`IMAGE_BUILDINFO_FILE`
When using the :ref:`ref-classes-image-buildinfo` class,
specifies the file in the image to write the build information into. The
default value is "``${sysconfdir}/buildinfo``".
:term:`IMAGE_BUILDINFO_VARS`
When using the :ref:`ref-classes-image-buildinfo` class,
specifies the list of variables to include in the `Build Configuration`
section of the output file (as a space-separated list). Defaults to
":term:`DISTRO` :term:`DISTRO_VERSION`".
:term:`IMAGE_CLASSES`
A list of classes that all images should inherit. This is typically used
to enable functionality across all image recipes.
Classes specified in :term:`IMAGE_CLASSES` must be located in the
``classes-recipe/`` or ``classes/`` subdirectories.
:term:`IMAGE_CMD`
Specifies the command to create the image file for a specific image
type, which corresponds to the value set in
:term:`IMAGE_FSTYPES`, (e.g. ``ext3``,
``btrfs``, and so forth). When setting this variable, you should use
an override for the associated type. Here is an example::
IMAGE_CMD:jffs2 = "mkfs.jffs2 --root=${IMAGE_ROOTFS} --faketime \
--output=${IMGDEPLOYDIR}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.jffs2 \
${EXTRA_IMAGECMD}"
You typically do not need to set this variable unless you are adding
support for a new image type. For more examples on how to set this
variable, see the :ref:`ref-classes-image_types`
class file, which is ``meta/classes-recipe/image_types.bbclass``.
:term:`IMAGE_DEVICE_TABLES`
Specifies one or more files that contain custom device tables that
are passed to the ``makedevs`` command as part of creating an image.
These files list basic device nodes that should be created under
``/dev`` within the image. If :term:`IMAGE_DEVICE_TABLES` is not set,
``files/device_table-minimal.txt`` is used, which is located by
:term:`BBPATH`. For details on how you should write
device table files, see ``meta/files/device_table-minimal.txt`` as an
example.
:term:`IMAGE_EFI_BOOT_FILES`
A space-separated list of files installed into the boot partition
when preparing an image using the Wic tool with the
``bootimg-efi`` source plugin. By default,
the files are
installed under the same name as the source files. To change the
installed name, separate it from the original name with a semi-colon
(;). Source files need to be located in
:term:`DEPLOY_DIR_IMAGE`. Here are two
examples::
IMAGE_EFI_BOOT_FILES = "${KERNEL_IMAGETYPE};bz2"
IMAGE_EFI_BOOT_FILES = "${KERNEL_IMAGETYPE} microcode.cpio"
Alternatively, source files can be picked up using a glob pattern. In
this case, the destination file must have the same name as the base
name of the source file path. To install files into a directory
within the target location, pass its name after a semi-colon (;).
Here are two examples::
IMAGE_EFI_BOOT_FILES = "boot/loader/*"
IMAGE_EFI_BOOT_FILES = "boot/loader/*;boot/"
The first example
installs all files from ``${DEPLOY_DIR_IMAGE}/boot/loader/``
into the root of the target partition. The second example installs
the same files into a ``boot`` directory within the target partition.
You can find information on how to use the Wic tool in the
":ref:`dev-manual/wic:creating partitioned images using wic`"
section of the Yocto Project Development Tasks Manual. Reference
material for Wic is located in the
":doc:`/ref-manual/kickstart`" chapter.
:term:`IMAGE_FEATURES`
The primary list of features to include in an image. Typically, you
configure this variable in an image recipe. Although you can use this
variable from your ``local.conf`` file, which is found in the
:term:`Build Directory`, best practices dictate that you do
not.
.. note::
To enable extra features from outside the image recipe, use the
:term:`EXTRA_IMAGE_FEATURES` variable.
For a list of image features that ships with the Yocto Project, see
the ":ref:`ref-features-image`" section.
For an example that shows how to customize your image by using this
variable, see the ":ref:`dev-manual/customizing-images:customizing images using custom \`\`image_features\`\` and \`\`extra_image_features\`\``"
section in the Yocto Project Development Tasks Manual.
:term:`IMAGE_FSTYPES`
Specifies the formats the OpenEmbedded build system uses during the
build when creating the root filesystem. For example, setting
:term:`IMAGE_FSTYPES` as follows causes the build system to create root
filesystems using two formats: ``.ext3`` and ``.tar.bz2``::
IMAGE_FSTYPES = "ext3 tar.bz2"
For the complete list of supported image formats from which you can
choose, see :term:`IMAGE_TYPES`.
.. note::
- If an image recipe uses the "inherit image" line and you are
setting :term:`IMAGE_FSTYPES` inside the recipe, you must set
:term:`IMAGE_FSTYPES` prior to using the "inherit image" line.
- Due to the way the OpenEmbedded build system processes this
variable, you cannot update its contents by using ``:append``
or ``:prepend``. You must use the ``+=`` operator to add one or
more options to the :term:`IMAGE_FSTYPES` variable.
:term:`IMAGE_INSTALL`
Used by recipes to specify the packages to install into an image
through the :ref:`ref-classes-image` class. Use the
:term:`IMAGE_INSTALL` variable with care to avoid ordering issues.
Image recipes set :term:`IMAGE_INSTALL` to specify the packages to
install into an image through :ref:`ref-classes-image`. Additionally,
there are "helper" classes such as the :ref:`ref-classes-core-image`
class which can take lists used with :term:`IMAGE_FEATURES` and turn
them into auto-generated entries in :term:`IMAGE_INSTALL` in addition
to its default contents.
When you use this variable, it is best to use it as follows::
IMAGE_INSTALL:append = " package-name"
Be sure to include the space
between the quotation character and the start of the package name or
names.
.. note::
- When working with a
:ref:`core-image-minimal-initramfs <ref-manual/images:images>`
image, do not use the :term:`IMAGE_INSTALL` variable to specify
packages for installation. Instead, use the
:term:`PACKAGE_INSTALL` variable, which
allows the initial RAM filesystem (:term:`Initramfs`) recipe to use a
fixed set of packages and not be affected by :term:`IMAGE_INSTALL`.
For information on creating an :term:`Initramfs`, see the
":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`"
section in the Yocto Project Development Tasks Manual.
- Using :term:`IMAGE_INSTALL` with the
:ref:`+= <bitbake:bitbake-user-manual/bitbake-user-manual-metadata:appending (+=) and prepending (=+) with spaces>`
BitBake operator within the ``/conf/local.conf`` file or from
within an image recipe is not recommended. Use of this operator
in these ways can cause ordering issues. Since
:ref:`ref-classes-core-image` sets :term:`IMAGE_INSTALL` to a default
value using the
:ref:`?= <bitbake:bitbake-user-manual/bitbake-user-manual-metadata:setting a default value (?=)>`
operator, using a ``+=`` operation against :term:`IMAGE_INSTALL`
results in unexpected behavior when used within
``conf/local.conf``. Furthermore, the same operation from
within an image recipe may or may not succeed depending on the
specific situation. In both these cases, the behavior is
contrary to how most users expect the ``+=`` operator to work.
:term:`IMAGE_LINGUAS`
Specifies the list of locales to install into the image during the
root filesystem construction process. The OpenEmbedded build system
automatically splits locale files, which are used for localization,
into separate packages. Setting the :term:`IMAGE_LINGUAS` variable
ensures that any locale packages that correspond to packages already
selected for installation into the image are also installed. Here is
an example::
IMAGE_LINGUAS = "pt-br de-de"
In this example, the build system ensures any Brazilian Portuguese
and German locale files that correspond to packages in the image are
installed (i.e. ``*-locale-pt-br`` and ``*-locale-de-de`` as well as
``*-locale-pt`` and ``*-locale-de``, since some software packages
only provide locale files by language and not by country-specific
language).
See the :term:`GLIBC_GENERATE_LOCALES`
variable for information on generating GLIBC locales.
:term:`IMAGE_LINK_NAME`
The name of the output image symlink (which does not include
the version part as :term:`IMAGE_NAME` does). The default value
is derived using the :term:`IMAGE_BASENAME` and :term:`MACHINE`
variables::
IMAGE_LINK_NAME ?= "${IMAGE_BASENAME}-${MACHINE}"
:term:`IMAGE_MANIFEST`
The manifest file for the image. This file lists all the installed
packages that make up the image. The file contains package
information on a line-per-package basis as follows::
packagename packagearch version
The :ref:`rootfs-postcommands <ref-classes-rootfs*>` class defines the manifest
file as follows::
IMAGE_MANIFEST ="${IMGDEPLOYDIR}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.manifest"
The location is
derived using the :term:`IMGDEPLOYDIR`
and :term:`IMAGE_NAME` variables. You can find
information on how the image is created in the ":ref:`overview-manual/concepts:image generation`"
section in the Yocto Project Overview and Concepts Manual.
:term:`IMAGE_NAME`
The name of the output image files minus the extension. This variable
is derived using the :term:`IMAGE_BASENAME`,
:term:`MACHINE`, and :term:`IMAGE_VERSION_SUFFIX`
variables::
IMAGE_NAME ?= "${IMAGE_BASENAME}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`IMAGE_NAME_SUFFIX`
Suffix used for the image output filename --- defaults to ``".rootfs"``
to distinguish the image file from other files created during image
building; however if this suffix is redundant or not desired you can
clear the value of this variable (set the value to ""). For example,
this is typically cleared in :term:`Initramfs` image recipes.
:term:`IMAGE_OVERHEAD_FACTOR`
Defines a multiplier that the build system applies to the initial
image size for cases when the multiplier times the returned disk
usage value for the image is greater than the sum of
:term:`IMAGE_ROOTFS_SIZE` and :term:`IMAGE_ROOTFS_EXTRA_SPACE`. The result of
the multiplier applied to the initial image size creates free disk
space in the image as overhead. By default, the build process uses a
multiplier of 1.3 for this variable. This default value results in
30% free disk space added to the image when this method is used to
determine the final generated image size. You should be aware that
post install scripts and the package management system uses disk
space inside this overhead area. Consequently, the multiplier does
not produce an image with all the theoretical free disk space. See
:term:`IMAGE_ROOTFS_SIZE` for information on how the build system
determines the overall image size.
The default 30% free disk space typically gives the image enough room
to boot and allows for basic post installs while still leaving a
small amount of free disk space. If 30% free space is inadequate, you
can increase the default value. For example, the following setting
gives you 50% free space added to the image::
IMAGE_OVERHEAD_FACTOR = "1.5"
Alternatively, you can ensure a specific amount of free disk space is
added to the image by using the :term:`IMAGE_ROOTFS_EXTRA_SPACE`
variable.
:term:`IMAGE_PKGTYPE`
Defines the package type (i.e. DEB, RPM, IPK, or TAR) used by the
OpenEmbedded build system. The variable is defined appropriately by
the :ref:`ref-classes-package_deb`, :ref:`ref-classes-package_rpm`,
:ref:`ref-classes-package_ipk`, or :ref:`ref-classes-package_tar` class.
.. note::
The ``package_tar`` class is broken and is not supported. It is
recommended that you do not use it.
The :ref:`ref-classes-populate-sdk-*` and :ref:`ref-classes-image`
classes use the :term:`IMAGE_PKGTYPE` for packaging up images and SDKs.
You should not set the :term:`IMAGE_PKGTYPE` manually. Rather, the
variable is set indirectly through the appropriate
:ref:`package_* <ref-classes-package>` class using the
:term:`PACKAGE_CLASSES` variable. The
OpenEmbedded build system uses the first package type (e.g. DEB, RPM,
or IPK) that appears with the variable
.. note::
Files using the ``.tar`` format are never used as a substitute
packaging format for DEB, RPM, and IPK formatted files for your image
or SDK.
:term:`IMAGE_POSTPROCESS_COMMAND`
Specifies a list of functions to call once the OpenEmbedded build
system creates the final image output files. You can specify
functions separated by semicolons::
IMAGE_POSTPROCESS_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within the
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`IMAGE_PREPROCESS_COMMAND`
Specifies a list of functions to call before the OpenEmbedded build
system creates the final image output files. You can specify
functions separated by semicolons::
IMAGE_PREPROCESS_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within the
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`IMAGE_ROOTFS`
The location of the root filesystem while it is under construction
(i.e. during the :ref:`ref-tasks-rootfs` task). This
variable is not configurable. Do not change it.
:term:`IMAGE_ROOTFS_ALIGNMENT`
Specifies the alignment for the output image file in Kbytes. If the
size of the image is not a multiple of this value, then the size is
rounded up to the nearest multiple of the value. The default value is
"1". See :term:`IMAGE_ROOTFS_SIZE` for
additional information.
:term:`IMAGE_ROOTFS_EXTRA_SPACE`
Defines additional free disk space created in the image in Kbytes. By
default, this variable is set to "0". This free disk space is added
to the image after the build system determines the image size as
described in :term:`IMAGE_ROOTFS_SIZE`.
This variable is particularly useful when you want to ensure that a
specific amount of free disk space is available on a device after an
image is installed and running. For example, to be sure 5 Gbytes of
free disk space is available, set the variable as follows::
IMAGE_ROOTFS_EXTRA_SPACE = "5242880"
For example, the Yocto Project Build Appliance specifically requests
40 Gbytes of extra space with the line::
IMAGE_ROOTFS_EXTRA_SPACE = "41943040"
:term:`IMAGE_ROOTFS_SIZE`
Defines the size in Kbytes for the generated image. The OpenEmbedded
build system determines the final size for the generated image using
an algorithm that takes into account the initial disk space used for
the generated image, a requested size for the image, and requested
additional free disk space to be added to the image. Programatically,
the build system determines the final size of the generated image as
follows::
if (image-du * overhead) < rootfs-size:
internal-rootfs-size = rootfs-size + xspace
else:
internal-rootfs-size = (image-du * overhead) + xspace
where:
image-du = Returned value of the du command on the image.
overhead = IMAGE_OVERHEAD_FACTOR
rootfs-size = IMAGE_ROOTFS_SIZE
internal-rootfs-size = Initial root filesystem size before any modifications.
xspace = IMAGE_ROOTFS_EXTRA_SPACE
See the :term:`IMAGE_OVERHEAD_FACTOR`
and :term:`IMAGE_ROOTFS_EXTRA_SPACE`
variables for related information.
:term:`IMAGE_TYPEDEP`
Specifies a dependency from one image type on another. Here is an
example from the :ref:`ref-classes-image-live` class::
IMAGE_TYPEDEP:live = "ext3"
In the previous example, the variable ensures that when "live" is
listed with the :term:`IMAGE_FSTYPES` variable,
the OpenEmbedded build system produces an ``ext3`` image first since
one of the components of the live image is an ``ext3`` formatted
partition containing the root filesystem.
:term:`IMAGE_TYPES`
Specifies the complete list of supported image types by default:
- btrfs
- container
- cpio
- cpio.gz
- cpio.lz4
- cpio.lzma
- cpio.xz
- cramfs
- erofs
- erofs-lz4
- erofs-lz4hc
- ext2
- ext2.bz2
- ext2.gz
- ext2.lzma
- ext3
- ext3.gz
- ext4
- ext4.gz
- f2fs
- hddimg
- iso
- jffs2
- jffs2.sum
- multiubi
- squashfs
- squashfs-lz4
- squashfs-lzo
- squashfs-xz
- tar
- tar.bz2
- tar.gz
- tar.lz4
- tar.xz
- tar.zst
- ubi
- ubifs
- wic
- wic.bz2
- wic.gz
- wic.lzma
For more information about these types of images, see
``meta/classes-recipe/image_types*.bbclass`` in the :term:`Source Directory`.
:term:`IMAGE_VERSION_SUFFIX`
Version suffix that is part of the default :term:`IMAGE_NAME` and
:term:`KERNEL_ARTIFACT_NAME` values.
Defaults to ``"-${DATETIME}"``, however you could set this to a
version string that comes from your external build environment if
desired, and this suffix would then be used consistently across
the build artifacts.
:term:`IMGDEPLOYDIR`
When inheriting the :ref:`ref-classes-image` class directly or
through the :ref:`ref-classes-core-image` class, the
:term:`IMGDEPLOYDIR` points to a temporary work area for deployed files
that is set in the ``image`` class as follows::
IMGDEPLOYDIR = "${WORKDIR}/deploy-${PN}-image-complete"
Recipes inheriting the :ref:`ref-classes-image` class should copy
files to be deployed into :term:`IMGDEPLOYDIR`, and the class will take
care of copying them into :term:`DEPLOY_DIR_IMAGE` afterwards.
:term:`INC_PR`
Helps define the recipe revision for recipes that share a common
``include`` file. You can think of this variable as part of the
recipe revision as set from within an include file.
Suppose, for example, you have a set of recipes that are used across
several projects. And, within each of those recipes the revision (its
:term:`PR` value) is set accordingly. In this case, when
the revision of those recipes changes, the burden is on you to find
all those recipes and be sure that they get changed to reflect the
updated version of the recipe. In this scenario, it can get
complicated when recipes that are used in many places and provide
common functionality are upgraded to a new revision.
A more efficient way of dealing with this situation is to set the
:term:`INC_PR` variable inside the ``include`` files that the recipes
share and then expand the :term:`INC_PR` variable within the recipes to
help define the recipe revision.
The following provides an example that shows how to use the
:term:`INC_PR` variable given a common ``include`` file that defines the
variable. Once the variable is defined in the ``include`` file, you
can use the variable to set the :term:`PR` values in each recipe. You
will notice that when you set a recipe's :term:`PR` you can provide more
granular revisioning by appending values to the :term:`INC_PR` variable::
recipes-graphics/xorg-font/xorg-font-common.inc:INC_PR = "r2"
recipes-graphics/xorg-font/encodings_1.0.4.bb:PR = "${INC_PR}.1"
recipes-graphics/xorg-font/font-util_1.3.0.bb:PR = "${INC_PR}.0"
recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
The
first line of the example establishes the baseline revision to be
used for all recipes that use the ``include`` file. The remaining
lines in the example are from individual recipes and show how the
:term:`PR` value is set.
:term:`INCOMPATIBLE_LICENSE`
Specifies a space-separated list of license names (as they would
appear in :term:`LICENSE`) that should be excluded
from the build. Recipes that provide no alternatives to listed
incompatible licenses are not built. Packages that are individually
licensed with the specified incompatible licenses will be deleted.
There is some support for wildcards in this variable's value,
however it is restricted to specific licenses. Currently only
these wildcards are allowed and expand as follows:
- ``AGPL-3.0*"``: ``AGPL-3.0-only``, ``AGPL-3.0-or-later``
- ``GPL-3.0*``: ``GPL-3.0-only``, ``GPL-3.0-or-later``
- ``LGPL-3.0*``: ``LGPL-3.0-only``, ``LGPL-3.0-or-later``
.. note::
This functionality is only regularly tested using the following
setting::
INCOMPATIBLE_LICENSE = "GPL-3.0* LGPL-3.0* AGPL-3.0*"
Although you can use other settings, you might be required to
remove dependencies on (or provide alternatives to) components that
are required to produce a functional system image.
:term:`INCOMPATIBLE_LICENSE_EXCEPTIONS`
Specifies a space-separated list of package and license pairs that
are allowed to be used even if the license is specified in
:term:`INCOMPATIBLE_LICENSE`. The package and license pairs are
separated using a colon. Example::
INCOMPATIBLE_LICENSE_EXCEPTIONS = "gdbserver:GPL-3.0-only gdbserver:LGPL-3.0-only"
:term:`INHERIT`
Causes the named class or classes to be inherited globally. Anonymous
functions in the class or classes are not executed for the base
configuration and in each individual recipe. The OpenEmbedded build
system ignores changes to :term:`INHERIT` in individual recipes.
Classes inherited using :term:`INHERIT` must be located in the
``classes-global/`` or ``classes/`` subdirectories.
For more information on :term:`INHERIT`, see the
:ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:\`\`inherit\`\` configuration directive`"
section in the BitBake User Manual.
:term:`INHERIT_DISTRO`
Lists classes that will be inherited at the distribution level. It is
unlikely that you want to edit this variable.
Classes specified in :term:`INHERIT_DISTRO` must be located in the
``classes-global/`` or ``classes/`` subdirectories.
The default value of the variable is set as follows in the
``meta/conf/distro/defaultsetup.conf`` file::
INHERIT_DISTRO ?= "debian devshell sstate license"
:term:`INHIBIT_DEFAULT_DEPS`
Prevents the default dependencies, namely the C compiler and standard
C library (libc), from being added to :term:`DEPENDS`.
This variable is usually used within recipes that do not require any
compilation using the C compiler.
Set the variable to "1" to prevent the default dependencies from
being added.
:term:`INHIBIT_PACKAGE_DEBUG_SPLIT`
Prevents the OpenEmbedded build system from splitting out debug
information during packaging. By default, the build system splits out
debugging information during the
:ref:`ref-tasks-package` task. For more information on
how debug information is split out, see the
:term:`PACKAGE_DEBUG_SPLIT_STYLE`
variable.
To prevent the build system from splitting out debug information
during packaging, set the :term:`INHIBIT_PACKAGE_DEBUG_SPLIT` variable as
follows::
INHIBIT_PACKAGE_DEBUG_SPLIT = "1"
:term:`INHIBIT_PACKAGE_STRIP`
If set to "1", causes the build to not strip binaries in resulting
packages and prevents the ``-dbg`` package from containing the source
files.
By default, the OpenEmbedded build system strips binaries and puts
the debugging symbols into ``${``\ :term:`PN`\ ``}-dbg``.
Consequently, you should not set :term:`INHIBIT_PACKAGE_STRIP` when you
plan to debug in general.
:term:`INHIBIT_SYSROOT_STRIP`
If set to "1", causes the build to not strip binaries in the
resulting sysroot.
By default, the OpenEmbedded build system strips binaries in the
resulting sysroot. When you specifically set the
:term:`INHIBIT_SYSROOT_STRIP` variable to "1" in your recipe, you inhibit
this stripping.
If you want to use this variable, include the :ref:`ref-classes-staging`
class. This class uses a ``sys_strip()`` function to test for the variable
and acts accordingly.
.. note::
Use of the :term:`INHIBIT_SYSROOT_STRIP` variable occurs in rare and
special circumstances. For example, suppose you are building
bare-metal firmware by using an external GCC toolchain. Furthermore,
even if the toolchain's binaries are strippable, there are other files
needed for the build that are not strippable.
:term:`Initramfs`
An Initial RAM Filesystem (:term:`Initramfs`) is an optionally compressed
:wikipedia:`cpio <Cpio>` archive which is extracted
by the Linux kernel into RAM in a special :wikipedia:`tmpfs <Tmpfs>`
instance, used as the initial root filesystem.
This is a replacement for the legacy init RAM disk ("initrd")
technique, booting on an emulated block device in RAM, but being less
efficient because of the overhead of going through a filesystem and
having to duplicate accessed file contents in the file cache in RAM,
as for any block device.
.. note:
As far as bootloaders are concerned, :term:`Initramfs` and "initrd"
images are still copied to RAM in the same way. That's why most
most bootloaders refer to :term:`Initramfs` images as "initrd"
or "init RAM disk".
This kind of mechanism is typically used for two reasons:
- For booting the same kernel binary on multiple systems requiring
different device drivers. The :term:`Initramfs` image is then customized
for each type of system, to include the specific kernel modules
necessary to access the final root filesystem. This technique
is used on all GNU / Linux distributions for desktops and servers.
- For booting faster. As the root filesystem is extracted into RAM,
accessing the first user-space applications is very fast, compared
to having to initialize a block device, to access multiple blocks
from it, and to go through a filesystem having its own overhead.
For example, this allows to display a splashscreen very early,
and to later take care of mounting the final root filesystem and
loading less time-critical kernel drivers.
This cpio archive can either be loaded to RAM by the bootloader,
or be included in the kernel binary.
For information on creating and using an :term:`Initramfs`, see the
":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`"
section in the Yocto Project Development Tasks Manual.
:term:`INITRAMFS_DEPLOY_DIR_IMAGE`
Indicates the deploy directory used by :ref:`ref-tasks-bundle_initramfs`
where the :term:`INITRAMFS_IMAGE` will be fetched from. This variable is
set by default to ``${DEPLOY_DIR_IMAGE}`` in the
:ref:`ref-classes-kernel` class and it's only meant to be changed when
building an :term:`Initramfs` image from a separate multiconfig via
:term:`INITRAMFS_MULTICONFIG`.
:term:`INITRAMFS_FSTYPES`
Defines the format for the output image of an initial RAM filesystem
(:term:`Initramfs`), which is used during boot. Supported formats are the
same as those supported by the
:term:`IMAGE_FSTYPES` variable.
The default value of this variable, which is set in the
``meta/conf/bitbake.conf`` configuration file in the
:term:`Source Directory`, is "cpio.gz". The Linux kernel's
:term:`Initramfs` mechanism, as opposed to the initial RAM filesystem
:wikipedia:`initrd <Initrd>` mechanism, expects
an optionally compressed cpio archive.
:term:`INITRAMFS_IMAGE`
Specifies the :term:`PROVIDES` name of an image
recipe that is used to build an initial RAM filesystem (:term:`Initramfs`)
image. In other words, the :term:`INITRAMFS_IMAGE` variable causes an
additional recipe to be built as a dependency to whatever root
filesystem recipe you might be using (e.g. ``core-image-sato``). The
:term:`Initramfs` image recipe you provide should set
:term:`IMAGE_FSTYPES` to
:term:`INITRAMFS_FSTYPES`.
An :term:`Initramfs` image provides a temporary root filesystem used for
early system initialization (e.g. loading of modules needed to locate
and mount the "real" root filesystem).
.. note::
See the ``meta/recipes-core/images/core-image-minimal-initramfs.bb``
recipe in the :term:`Source Directory`
for an example :term:`Initramfs` recipe. To select this sample recipe as
the one built to provide the :term:`Initramfs` image, set :term:`INITRAMFS_IMAGE`
to "core-image-minimal-initramfs".
You can also find more information by referencing the
``meta-poky/conf/templates/default/local.conf.sample.extended``
configuration file in the Source Directory, the :ref:`ref-classes-image`
class, and the :ref:`ref-classes-kernel` class to see how to use the
:term:`INITRAMFS_IMAGE` variable.
If :term:`INITRAMFS_IMAGE` is empty, which is the default, then no
:term:`Initramfs` image is built.
For more information, you can also see the
:term:`INITRAMFS_IMAGE_BUNDLE`
variable, which allows the generated image to be bundled inside the
kernel image. Additionally, for information on creating an :term:`Initramfs`
image, see the ":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`" section
in the Yocto Project Development Tasks Manual.
:term:`INITRAMFS_IMAGE_BUNDLE`
Controls whether or not the image recipe specified by
:term:`INITRAMFS_IMAGE` is run through an
extra pass
(:ref:`ref-tasks-bundle_initramfs`) during
kernel compilation in order to build a single binary that contains
both the kernel image and the initial RAM filesystem (:term:`Initramfs`)
image. This makes use of the
:term:`CONFIG_INITRAMFS_SOURCE` kernel
feature.
.. note::
Bundling the :term:`Initramfs` with the kernel conflates the code in the
:term:`Initramfs` with the GPLv2 licensed Linux kernel binary. Thus only GPLv2
compatible software may be part of a bundled :term:`Initramfs`.
.. note::
Using an extra compilation pass to bundle the :term:`Initramfs` avoids a
circular dependency between the kernel recipe and the :term:`Initramfs`
recipe should the :term:`Initramfs` include kernel modules. Should that be
the case, the :term:`Initramfs` recipe depends on the kernel for the
kernel modules, and the kernel depends on the :term:`Initramfs` recipe
since the :term:`Initramfs` is bundled inside the kernel image.
The combined binary is deposited into the ``tmp/deploy`` directory,
which is part of the :term:`Build Directory`.
Setting the variable to "1" in a configuration file causes the
OpenEmbedded build system to generate a kernel image with the
:term:`Initramfs` specified in :term:`INITRAMFS_IMAGE` bundled within::
INITRAMFS_IMAGE_BUNDLE = "1"
By default, the :ref:`ref-classes-kernel` class sets this variable to a
null string as follows::
INITRAMFS_IMAGE_BUNDLE ?= ""
.. note::
You must set the :term:`INITRAMFS_IMAGE_BUNDLE` variable in a
configuration file. You cannot set the variable in a recipe file.
See the
:yocto_git:`local.conf.sample.extended </poky/tree/meta-poky/conf/templates/default/local.conf.sample.extended>`
file for additional information. Also, for information on creating an
:term:`Initramfs`, see the ":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`" section
in the Yocto Project Development Tasks Manual.
:term:`INITRAMFS_LINK_NAME`
The link name of the initial RAM filesystem image. This variable is
set in the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as
follows::
INITRAMFS_LINK_NAME ?= "initramfs-${KERNEL_ARTIFACT_LINK_NAME}"
The value of the
``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
file, has the following value::
KERNEL_ARTIFACT_LINK_NAME ?= "${MACHINE}"
See the :term:`MACHINE` variable for additional
information.
:term:`INITRAMFS_MULTICONFIG`
Defines the multiconfig to create a multiconfig dependency to be used by
the :ref:`ref-classes-kernel` class.
This allows the kernel to bundle an :term:`INITRAMFS_IMAGE` coming from
a separate multiconfig, this is meant to be used in addition to :term:`INITRAMFS_DEPLOY_DIR_IMAGE`.
For more information on how to bundle an :term:`Initramfs` image from a separate
multiconfig see the ":ref:`dev-manual/building:Bundling an Initramfs Image From a Separate Multiconfig`"
section in the Yocto Project Development Tasks Manual.
:term:`INITRAMFS_NAME`
The base name of the initial RAM filesystem image. This variable is
set in the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as
follows::
INITRAMFS_NAME ?= "initramfs-${KERNEL_ARTIFACT_NAME}"
The value of the :term:`KERNEL_ARTIFACT_NAME`
variable, which is set in the same file, has the following value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`INITRD`
Indicates list of filesystem images to concatenate and use as an
initial RAM disk (``initrd``).
The :term:`INITRD` variable is an optional variable used with the
:ref:`ref-classes-image-live` class.
:term:`INITRD_IMAGE`
When building a "live" bootable image (i.e. when
:term:`IMAGE_FSTYPES` contains "live"),
:term:`INITRD_IMAGE` specifies the image recipe that should be built to
provide the initial RAM disk image. The default value is
"core-image-minimal-initramfs".
See the :ref:`ref-classes-image-live` class for more information.
:term:`INITSCRIPT_NAME`
The filename of the initialization script as installed to
``${sysconfdir}/init.d``.
This variable is used in recipes when using :ref:`ref-classes-update-rc.d`.
The variable is mandatory.
:term:`INITSCRIPT_PACKAGES`
A list of the packages that contain initscripts. If multiple packages
are specified, you need to append the package name to the other
``INITSCRIPT_*`` as an override.
This variable is used in recipes when using :ref:`ref-classes-update-rc.d`.
The variable is optional and defaults to the :term:`PN`
variable.
:term:`INITSCRIPT_PARAMS`
Specifies the options to pass to ``update-rc.d``. Here is an example::
INITSCRIPT_PARAMS = "start 99 5 2 . stop 20 0 1 6 ."
In this example, the script has a runlevel of 99, starts the script
in initlevels 2 and 5, and stops the script in levels 0, 1 and 6.
The variable's default value is "defaults", which is set in the
:ref:`ref-classes-update-rc.d` class.
The value in :term:`INITSCRIPT_PARAMS` is passed through to the
``update-rc.d`` command. For more information on valid parameters,
please see the ``update-rc.d`` manual page at
https://manpages.debian.org/buster/init-system-helpers/update-rc.d.8.en.html
:term:`INSANE_SKIP`
Specifies the QA checks to skip for a specific package within a
recipe. For example, to skip the check for symbolic link ``.so``
files in the main package of a recipe, add the following to the
recipe. The package name override must be used, which in this example
is ``${PN}``::
INSANE_SKIP:${PN} += "dev-so"
See the ":ref:`ref-classes-insane`" section for a
list of the valid QA checks you can specify using this variable.
:term:`INSTALL_TIMEZONE_FILE`
By default, the ``tzdata`` recipe packages an ``/etc/timezone`` file.
Set the :term:`INSTALL_TIMEZONE_FILE` variable to "0" at the
configuration level to disable this behavior.
:term:`IPK_FEED_URIS`
When the IPK backend is in use and package management is enabled on
the target, you can use this variable to set up ``opkg`` in the
target image to point to package feeds on a nominated server. Once
the feed is established, you can perform installations or upgrades
using the package manager at runtime.
:term:`KARCH`
Defines the kernel architecture used when assembling the
configuration. Architectures supported for this release are:
- powerpc
- i386
- x86_64
- arm
- qemu
- mips
You define the :term:`KARCH` variable in the :ref:`kernel-dev/advanced:bsp descriptions`.
:term:`KBRANCH`
A regular expression used by the build process to explicitly identify
the kernel branch that is validated, patched, and configured during a
build. You must set this variable to ensure the exact kernel branch
you want is being used by the build process.
Values for this variable are set in the kernel's recipe file and the
kernel's append file. For example, if you are using the
``linux-yocto_4.12`` kernel, the kernel recipe file is the
``meta/recipes-kernel/linux/linux-yocto_4.12.bb`` file. :term:`KBRANCH`
is set as follows in that kernel recipe file::
KBRANCH ?= "standard/base"
This variable is also used from the kernel's append file to identify
the kernel branch specific to a particular machine or target
hardware. Continuing with the previous kernel example, the kernel's
append file (i.e. ``linux-yocto_4.12.bbappend``) is located in the
BSP layer for a given machine. For example, the append file for the
Beaglebone, EdgeRouter, and generic versions of both 32 and 64-bit IA
machines (``meta-yocto-bsp``) is named
``meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.12.bbappend``.
Here are the related statements from that append file::
KBRANCH:genericx86 = "standard/base"
KBRANCH:genericx86-64 = "standard/base"
KBRANCH:edgerouter = "standard/edgerouter"
KBRANCH:beaglebone = "standard/beaglebone"
The :term:`KBRANCH` statements
identify the kernel branch to use when building for each supported
BSP.
:term:`KBUILD_DEFCONFIG`
When used with the :ref:`ref-classes-kernel-yocto`
class, specifies an "in-tree" kernel configuration file for use
during a kernel build.
Typically, when using a ``defconfig`` to configure a kernel during a
build, you place the file in your layer in the same manner as you
would place patch files and configuration fragment files (i.e.
"out-of-tree"). However, if you want to use a ``defconfig`` file that
is part of the kernel tree (i.e. "in-tree"), you can use the
:term:`KBUILD_DEFCONFIG` variable and append the
:term:`KMACHINE` variable to point to the
``defconfig`` file.
To use the variable, set it in the append file for your kernel recipe
using the following form::
KBUILD_DEFCONFIG_KMACHINE ?= defconfig_file
Here is an example from a "raspberrypi2" :term:`KMACHINE` build that uses
a ``defconfig`` file named "bcm2709_defconfig"::
KBUILD_DEFCONFIG:raspberrypi2 = "bcm2709_defconfig"
As an alternative, you can use the following within your append file::
KBUILD_DEFCONFIG:pn-linux-yocto ?= "defconfig_file"
For more
information on how to use the :term:`KBUILD_DEFCONFIG` variable, see the
":ref:`kernel-dev/common:using an "in-tree" \`\`defconfig\`\` file`"
section in the Yocto Project Linux Kernel Development Manual.
:term:`KCONFIG_MODE`
When used with the :ref:`ref-classes-kernel-yocto`
class, specifies the kernel configuration values to use for options
not specified in the provided ``defconfig`` file. Valid options are::
KCONFIG_MODE = "alldefconfig"
KCONFIG_MODE = "allnoconfig"
In ``alldefconfig`` mode the options not explicitly specified will be
assigned their Kconfig default value. In ``allnoconfig`` mode the
options not explicitly specified will be disabled in the kernel
config.
In case :term:`KCONFIG_MODE` is not set the behaviour will depend on where
the ``defconfig`` file is coming from. An "in-tree" ``defconfig`` file
will be handled in ``alldefconfig`` mode, a ``defconfig`` file placed
in ``${WORKDIR}`` through a meta-layer will be handled in
``allnoconfig`` mode.
An "in-tree" ``defconfig`` file can be selected via the
:term:`KBUILD_DEFCONFIG` variable. :term:`KCONFIG_MODE` does not need to
be explicitly set.
A ``defconfig`` file compatible with ``allnoconfig`` mode can be
generated by copying the ``.config`` file from a working Linux kernel
build, renaming it to ``defconfig`` and placing it into the Linux
kernel ``${WORKDIR}`` through your meta-layer. :term:`KCONFIG_MODE` does
not need to be explicitly set.
A ``defconfig`` file compatible with ``alldefconfig`` mode can be
generated using the
:ref:`ref-tasks-savedefconfig`
task and placed into the Linux kernel ``${WORKDIR}`` through your
meta-layer. Explicitely set :term:`KCONFIG_MODE`::
KCONFIG_MODE = "alldefconfig"
:term:`KERNEL_ALT_IMAGETYPE`
Specifies an alternate kernel image type for creation in addition to
the kernel image type specified using the :term:`KERNEL_IMAGETYPE` and
:term:`KERNEL_IMAGETYPES` variables.
:term:`KERNEL_ARTIFACT_NAME`
Specifies the name of all of the build artifacts. You can change the
name of the artifacts by changing the :term:`KERNEL_ARTIFACT_NAME`
variable.
The value of :term:`KERNEL_ARTIFACT_NAME`, which is set in the
``meta/classes-recipe/kernel-artifact-names.bbclass`` file, has the
following default value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
See the :term:`PKGE`, :term:`PKGV`, :term:`PKGR`, :term:`MACHINE`
and :term:`IMAGE_VERSION_SUFFIX` variables for additional information.
:term:`KERNEL_CLASSES`
A list of classes defining kernel image types that the
:ref:`ref-classes-kernel` class should inherit. You typically
append this variable to enable extended image types. An example is
":ref:`ref-classes-kernel-fitimage`", which enables
fitImage support and resides in ``meta/classes-recipe/kernel-fitimage.bbclass``.
You can register custom kernel image types with the
:ref:`ref-classes-kernel` class using this variable.
:term:`KERNEL_DEBUG_TIMESTAMPS`
If set to "1", enables timestamping functionality during building
the kernel. The default is "0" to disable this for reproducibility
reasons.
:term:`KERNEL_DEPLOY_DEPEND`
Provides a means of controlling the dependency of an image recipe
on the kernel. The default value is "virtual/kernel:do_deploy",
however for a small initramfs image or other images that do not
need the kernel, this can be set to "" in the image recipe.
:term:`KERNEL_DEVICETREE`
Specifies the name of the generated Linux kernel device tree (i.e.
the ``.dtb``) file.
.. note::
There is legacy support for specifying the full path to the device
tree. However, providing just the ``.dtb`` file is preferred.
In order to use this variable, the :ref:`ref-classes-kernel-devicetree`
class must be inherited.
:term:`KERNEL_DTB_LINK_NAME`
The link name of the kernel device tree binary (DTB). This variable
is set in the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as
follows::
KERNEL_DTB_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}"
The
value of the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in
the same file, has the following value::
KERNEL_ARTIFACT_LINK_NAME ?= "${MACHINE}"
See the :term:`MACHINE` variable for additional
information.
:term:`KERNEL_DTB_NAME`
The base name of the kernel device tree binary (DTB). This variable
is set in the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as
follows::
KERNEL_DTB_NAME ?= "${KERNEL_ARTIFACT_NAME}"
The value of the :term:`KERNEL_ARTIFACT_NAME`
variable, which is set in the same file, has the following value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`KERNEL_DTC_FLAGS`
Specifies the ``dtc`` flags that are passed to the Linux kernel build
system when generating the device trees (via ``DTC_FLAGS`` environment
variable).
In order to use this variable, the :ref:`ref-classes-kernel-devicetree`
class must be inherited.
:term:`KERNEL_EXTRA_ARGS`
Specifies additional ``make`` command-line arguments the OpenEmbedded
build system passes on when compiling the kernel.
:term:`KERNEL_FEATURES`
Includes additional kernel metadata. In the OpenEmbedded build
system, the default Board Support Packages (BSPs)
:term:`Metadata` is provided through the
:term:`KMACHINE` and :term:`KBRANCH`
variables. You can use the :term:`KERNEL_FEATURES` variable from within
the kernel recipe or kernel append file to further add metadata for
all BSPs or specific BSPs.
The metadata you add through this variable includes config fragments
and features descriptions, which usually includes patches as well as
config fragments. You typically override the :term:`KERNEL_FEATURES`
variable for a specific machine. In this way, you can provide
validated, but optional, sets of kernel configurations and features.
For example, the following example from the ``linux-yocto-rt_4.12``
kernel recipe adds "netfilter" and "taskstats" features to all BSPs
as well as "virtio" configurations to all QEMU machines. The last two
statements add specific configurations to targeted machine types::
KERNEL_EXTRA_FEATURES ?= "features/netfilter/netfilter.scc features/taskstats/taskstats.scc"
KERNEL_FEATURES:append = " ${KERNEL_EXTRA_FEATURES}"
KERNEL_FEATURES:append:qemuall = " cfg/virtio.scc"
KERNEL_FEATURES:append:qemux86 = " cfg/sound.scc cfg/paravirt_kvm.scc"
KERNEL_FEATURES:append:qemux86-64 = " cfg/sound.scc"
:term:`KERNEL_FIT_LINK_NAME`
The link name of the kernel flattened image tree (FIT) image. This
variable is set in the ``meta/classes-recipe/kernel-artifact-names.bbclass``
file as follows::
KERNEL_FIT_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}"
The value of the
``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
file, has the following value::
KERNEL_ARTIFACT_LINK_NAME ?= "${MACHINE}"
See the :term:`MACHINE` variable for additional
information.
:term:`KERNEL_FIT_NAME`
The base name of the kernel flattened image tree (FIT) image. This
variable is set in the ``meta/classes-recipe/kernel-artifact-names.bbclass``
file as follows::
KERNEL_FIT_NAME ?= "${KERNEL_ARTIFACT_NAME}"
The value of the :term:`KERNEL_ARTIFACT_NAME`
variable, which is set in the same file, has the following value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`KERNEL_IMAGE_LINK_NAME`
The link name for the kernel image. This variable is set in the
``meta/classes-recipe/kernel-artifact-names.bbclass`` file as follows::
KERNEL_IMAGE_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}"
The value of
the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the same
file, has the following value::
KERNEL_ARTIFACT_LINK_NAME ?= "${MACHINE}"
See the :term:`MACHINE` variable for additional
information.
:term:`KERNEL_IMAGE_MAXSIZE`
Specifies the maximum size of the kernel image file in kilobytes. If
:term:`KERNEL_IMAGE_MAXSIZE` is set, the size of the kernel image file is
checked against the set value during the
:ref:`ref-tasks-sizecheck` task. The task fails if
the kernel image file is larger than the setting.
:term:`KERNEL_IMAGE_MAXSIZE` is useful for target devices that have a
limited amount of space in which the kernel image must be stored.
By default, this variable is not set, which means the size of the
kernel image is not checked.
:term:`KERNEL_IMAGE_NAME`
The base name of the kernel image. This variable is set in the
``meta/classes-recipe/kernel-artifact-names.bbclass`` file as follows::
KERNEL_IMAGE_NAME ?= "${KERNEL_ARTIFACT_NAME}"
The value of the
:term:`KERNEL_ARTIFACT_NAME` variable,
which is set in the same file, has the following value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`KERNEL_IMAGETYPE`
The type of kernel to build for a device, usually set by the machine
configuration files and defaults to "zImage". This variable is used
when building the kernel and is passed to ``make`` as the target to
build.
To build additional kernel image types, use :term:`KERNEL_IMAGETYPES`.
:term:`KERNEL_IMAGETYPES`
Lists additional types of kernel images to build for a device in addition
to image type specified in :term:`KERNEL_IMAGETYPE`. Usually set by the
machine configuration files.
:term:`KERNEL_MODULE_AUTOLOAD`
Lists kernel modules that need to be auto-loaded during boot.
.. note::
This variable replaces the deprecated :term:`module_autoload`
variable.
You can use the :term:`KERNEL_MODULE_AUTOLOAD` variable anywhere that it
can be recognized by the kernel recipe or by an out-of-tree kernel
module recipe (e.g. a machine configuration file, a distribution
configuration file, an append file for the recipe, or the recipe
itself).
Specify it as follows::
KERNEL_MODULE_AUTOLOAD += "module_name1 module_name2 module_name3"
Including :term:`KERNEL_MODULE_AUTOLOAD` causes the OpenEmbedded build
system to populate the ``/etc/modules-load.d/modname.conf`` file with
the list of modules to be auto-loaded on boot. The modules appear
one-per-line in the file. Here is an example of the most common use
case::
KERNEL_MODULE_AUTOLOAD += "module_name"
For information on how to populate the ``modname.conf`` file with
``modprobe.d`` syntax lines, see the :term:`KERNEL_MODULE_PROBECONF` variable.
:term:`KERNEL_MODULE_PROBECONF`
Provides a list of modules for which the OpenEmbedded build system
expects to find ``module_conf_``\ modname values that specify
configuration for each of the modules. For information on how to
provide those module configurations, see the
:term:`module_conf_* <module_conf>` variable.
:term:`KERNEL_PATH`
The location of the kernel sources. This variable is set to the value
of the :term:`STAGING_KERNEL_DIR` within the :ref:`ref-classes-module`
class. For information on how this variable is used, see the
":ref:`kernel-dev/common:incorporating out-of-tree modules`"
section in the Yocto Project Linux Kernel Development Manual.
To help maximize compatibility with out-of-tree drivers used to build
modules, the OpenEmbedded build system also recognizes and uses the
:term:`KERNEL_SRC` variable, which is identical to
the :term:`KERNEL_PATH` variable. Both variables are common variables
used by external Makefiles to point to the kernel source directory.
:term:`KERNEL_SRC`
The location of the kernel sources. This variable is set to the value
of the :term:`STAGING_KERNEL_DIR` within the :ref:`ref-classes-module`
class. For information on how this variable is used, see the
":ref:`kernel-dev/common:incorporating out-of-tree modules`"
section in the Yocto Project Linux Kernel Development Manual.
To help maximize compatibility with out-of-tree drivers used to build
modules, the OpenEmbedded build system also recognizes and uses the
:term:`KERNEL_PATH` variable, which is identical
to the :term:`KERNEL_SRC` variable. Both variables are common variables
used by external Makefiles to point to the kernel source directory.
:term:`KERNEL_VERSION`
Specifies the version of the kernel as extracted from ``version.h``
or ``utsrelease.h`` within the kernel sources. Effects of setting
this variable do not take effect until the kernel has been
configured. Consequently, attempting to refer to this variable in
contexts prior to configuration will not work.
:term:`KERNELDEPMODDEPEND`
Specifies whether the data referenced through
:term:`PKGDATA_DIR` is needed or not.
:term:`KERNELDEPMODDEPEND` does not control whether or not that data
exists, but simply whether or not it is used. If you do not need to
use the data, set the :term:`KERNELDEPMODDEPEND` variable in your
:term:`Initramfs` recipe. Setting the variable there when the data is not
needed avoids a potential dependency loop.
:term:`KFEATURE_DESCRIPTION`
Provides a short description of a configuration fragment. You use
this variable in the ``.scc`` file that describes a configuration
fragment file. Here is the variable used in a file named ``smp.scc``
to describe SMP being enabled::
define KFEATURE_DESCRIPTION "Enable SMP"
:term:`KMACHINE`
The machine as known by the kernel. Sometimes the machine name used
by the kernel does not match the machine name used by the
OpenEmbedded build system. For example, the machine name that the
OpenEmbedded build system understands as ``core2-32-intel-common``
goes by a different name in the Linux Yocto kernel. The kernel
understands that machine as ``intel-core2-32``. For cases like these,
the :term:`KMACHINE` variable maps the kernel machine name to the
OpenEmbedded build system machine name.
These mappings between different names occur in the Yocto Linux
Kernel's ``meta`` branch. As an example take a look in the
``common/recipes-kernel/linux/linux-yocto_3.19.bbappend`` file::
LINUX_VERSION:core2-32-intel-common = "3.19.0"
COMPATIBLE_MACHINE:core2-32-intel-common = "${MACHINE}"
SRCREV_meta:core2-32-intel-common = "8897ef68b30e7426bc1d39895e71fb155d694974"
SRCREV_machine:core2-32-intel-common = "43b9eced9ba8a57add36af07736344dcc383f711"
KMACHINE:core2-32-intel-common = "intel-core2-32"
KBRANCH:core2-32-intel-common = "standard/base"
KERNEL_FEATURES:append:core2-32-intel-common = " ${KERNEL_FEATURES_INTEL_COMMON}"
The :term:`KMACHINE` statement says
that the kernel understands the machine name as "intel-core2-32".
However, the OpenEmbedded build system understands the machine as
"core2-32-intel-common".
:term:`KTYPE`
Defines the kernel type to be used in assembling the configuration.
The linux-yocto recipes define "standard", "tiny", and "preempt-rt"
kernel types. See the ":ref:`kernel-dev/advanced:kernel types`"
section in the
Yocto Project Linux Kernel Development Manual for more information on
kernel types.
You define the :term:`KTYPE` variable in the
:ref:`kernel-dev/advanced:bsp descriptions`. The
value you use must match the value used for the
:term:`LINUX_KERNEL_TYPE` value used by the
kernel recipe.
:term:`LABELS`
Provides a list of targets for automatic configuration.
See the :ref:`ref-classes-grub-efi` class for more
information on how this variable is used.
:term:`LAYERDEPENDS`
Lists the layers, separated by spaces, on which this recipe depends.
Optionally, you can specify a specific layer version for a dependency
by adding it to the end of the layer name. Here is an example::
LAYERDEPENDS_mylayer = "anotherlayer (=3)"
In this previous example,
version 3 of "anotherlayer" is compared against
:term:`LAYERVERSION`\ ``_anotherlayer``.
An error is produced if any dependency is missing or the version
numbers (if specified) do not match exactly. This variable is used in
the ``conf/layer.conf`` file and must be suffixed with the name of
the specific layer (e.g. ``LAYERDEPENDS_mylayer``).
:term:`LAYERDIR`
When used inside the ``layer.conf`` configuration file, this variable
provides the path of the current layer. This variable is not
available outside of ``layer.conf`` and references are expanded
immediately when parsing of the file completes.
:term:`LAYERDIR_RE`
See :term:`bitbake:LAYERDIR_RE` in the BitBake manual.
:term:`LAYERRECOMMENDS`
Lists the layers, separated by spaces, recommended for use with this
layer.
Optionally, you can specify a specific layer version for a
recommendation by adding the version to the end of the layer name.
Here is an example::
LAYERRECOMMENDS_mylayer = "anotherlayer (=3)"
In this previous example, version 3 of "anotherlayer" is compared
against ``LAYERVERSION_anotherlayer``.
This variable is used in the ``conf/layer.conf`` file and must be
suffixed with the name of the specific layer (e.g.
``LAYERRECOMMENDS_mylayer``).
:term:`LAYERSERIES_COMPAT`
Lists the versions of the :term:`OpenEmbedded-Core (OE-Core)` for which
a layer is compatible. Using the :term:`LAYERSERIES_COMPAT` variable
allows the layer maintainer to indicate which combinations of the
layer and OE-Core can be expected to work. The variable gives the
system a way to detect when a layer has not been tested with new
releases of OE-Core (e.g. the layer is not maintained).
To specify the OE-Core versions for which a layer is compatible, use
this variable in your layer's ``conf/layer.conf`` configuration file.
For the list, use the Yocto Project
:yocto_wiki:`Release Name </Releases>` (e.g.
&DISTRO_NAME_NO_CAP;). To specify multiple OE-Core versions for the
layer, use a space-separated list::
LAYERSERIES_COMPAT_layer_root_name = "&DISTRO_NAME_NO_CAP; &DISTRO_NAME_NO_CAP_MINUS_ONE;"
.. note::
Setting :term:`LAYERSERIES_COMPAT` is required by the Yocto Project
Compatible version 2 standard.
The OpenEmbedded build system produces a warning if the variable
is not set for any given layer.
See the ":ref:`dev-manual/layers:creating your own layer`"
section in the Yocto Project Development Tasks Manual.
:term:`LAYERVERSION`
Optionally specifies the version of a layer as a single number. You
can use this within :term:`LAYERDEPENDS` for
another layer in order to depend on a specific version of the layer.
This variable is used in the ``conf/layer.conf`` file and must be
suffixed with the name of the specific layer (e.g.
``LAYERVERSION_mylayer``).
:term:`LD`
The minimal command and arguments used to run the linker.
:term:`LDFLAGS`
Specifies the flags to pass to the linker. This variable is exported
to an environment variable and thus made visible to the software
being built during the compilation step.
Default initialization for :term:`LDFLAGS` varies depending on what is
being built:
- :term:`TARGET_LDFLAGS` when building for the
target
- :term:`BUILD_LDFLAGS` when building for the
build host (i.e. ``-native``)
- :term:`BUILDSDK_LDFLAGS` when building for
an SDK (i.e. ``nativesdk-``)
:term:`LEAD_SONAME`
Specifies the lead (or primary) compiled library file (i.e. ``.so``)
that the :ref:`ref-classes-debian` class applies its
naming policy to given a recipe that packages multiple libraries.
This variable works in conjunction with the :ref:`ref-classes-debian`
class.
:term:`LIC_FILES_CHKSUM`
Checksums of the license text in the recipe source code.
This variable tracks changes in license text of the source code
files. If the license text is changed, it will trigger a build
failure, which gives the developer an opportunity to review any
license change.
This variable must be defined for all recipes (unless
:term:`LICENSE` is set to "CLOSED").
For more information, see the ":ref:`dev-manual/licenses:tracking license changes`"
section in the Yocto Project Development Tasks Manual.
:term:`LICENSE`
The list of source licenses for the recipe. Follow these rules:
- Do not use spaces within individual license names.
- Separate license names using \| (pipe) when there is a choice
between licenses.
- Separate license names using & (ampersand) when there are
multiple licenses for different parts of the source.
- You can use spaces between license names.
- For standard licenses, use the names of the files in
``meta/files/common-licenses/`` or the
:term:`SPDXLICENSEMAP` flag names defined in
``meta/conf/licenses.conf``.
Here are some examples::
LICENSE = "LGPL-2.1-only | GPL-3.0-only"
LICENSE = "MPL-1.0 & LGPL-2.1-only"
LICENSE = "GPL-2.0-or-later"
The first example is from the
recipes for Qt, which the user may choose to distribute under either
the LGPL version 2.1 or GPL version 3. The second example is from
Cairo where two licenses cover different parts of the source code.
The final example is from ``sysstat``, which presents a single
license.
You can also specify licenses on a per-package basis to handle
situations where components of the output have different licenses.
For example, a piece of software whose code is licensed under GPLv2
but has accompanying documentation licensed under the GNU Free
Documentation License 1.2 could be specified as follows::
LICENSE = "GFDL-1.2 & GPL-2.0-only"
LICENSE:${PN} = "GPL-2.0.only"
LICENSE:${PN}-doc = "GFDL-1.2"
:term:`LICENSE_CREATE_PACKAGE`
Setting :term:`LICENSE_CREATE_PACKAGE` to "1" causes the OpenEmbedded
build system to create an extra package (i.e.
``${``\ :term:`PN`\ ``}-lic``) for each recipe and to add
those packages to the
:term:`RRECOMMENDS`\ ``:${PN}``.
The ``${PN}-lic`` package installs a directory in
``/usr/share/licenses`` named ``${PN}``, which is the recipe's base
name, and installs files in that directory that contain license and
copyright information (i.e. copies of the appropriate license files
from ``meta/common-licenses`` that match the licenses specified in
the :term:`LICENSE` variable of the recipe metadata
and copies of files marked in
:term:`LIC_FILES_CHKSUM` as containing
license text).
For related information on providing license text, see the
:term:`COPY_LIC_DIRS` variable, the
:term:`COPY_LIC_MANIFEST` variable, and the
":ref:`dev-manual/licenses:providing license text`"
section in the Yocto Project Development Tasks Manual.
:term:`LICENSE_FLAGS`
Specifies additional flags for a recipe you must allow through
:term:`LICENSE_FLAGS_ACCEPTED` in
order for the recipe to be built. When providing multiple flags,
separate them with spaces.
This value is independent of :term:`LICENSE` and is
typically used to mark recipes that might require additional licenses
in order to be used in a commercial product. For more information,
see the
":ref:`dev-manual/licenses:enabling commercially licensed recipes`"
section in the Yocto Project Development Tasks Manual.
:term:`LICENSE_FLAGS_ACCEPTED`
Lists license flags that when specified in
:term:`LICENSE_FLAGS` within a recipe should not
prevent that recipe from being built. For more information, see the
":ref:`dev-manual/licenses:enabling commercially licensed recipes`"
section in the Yocto Project Development Tasks Manual.
:term:`LICENSE_PATH`
Path to additional licenses used during the build. By default, the
OpenEmbedded build system uses :term:`COMMON_LICENSE_DIR` to define the
directory that holds common license text used during the build. The
:term:`LICENSE_PATH` variable allows you to extend that location to other
areas that have additional licenses::
LICENSE_PATH += "path-to-additional-common-licenses"
:term:`LINUX_KERNEL_TYPE`
Defines the kernel type to be used in assembling the configuration.
The linux-yocto recipes define "standard", "tiny", and "preempt-rt"
kernel types. See the ":ref:`kernel-dev/advanced:kernel types`"
section in the
Yocto Project Linux Kernel Development Manual for more information on
kernel types.
If you do not specify a :term:`LINUX_KERNEL_TYPE`, it defaults to
"standard". Together with :term:`KMACHINE`, the
:term:`LINUX_KERNEL_TYPE` variable defines the search arguments used by
the kernel tools to find the appropriate description within the
kernel :term:`Metadata` with which to build out the sources
and configuration.
:term:`LINUX_VERSION`
The Linux version from ``kernel.org`` on which the Linux kernel image
being built using the OpenEmbedded build system is based. You define
this variable in the kernel recipe. For example, the
``linux-yocto-3.4.bb`` kernel recipe found in
``meta/recipes-kernel/linux`` defines the variables as follows::
LINUX_VERSION ?= "3.4.24"
The :term:`LINUX_VERSION` variable is used to define :term:`PV`
for the recipe::
PV = "${LINUX_VERSION}+git${SRCPV}"
:term:`LINUX_VERSION_EXTENSION`
A string extension compiled into the version string of the Linux
kernel built with the OpenEmbedded build system. You define this
variable in the kernel recipe. For example, the linux-yocto kernel
recipes all define the variable as follows::
LINUX_VERSION_EXTENSION ?= "-yocto-${LINUX_KERNEL_TYPE}"
Defining this variable essentially sets the Linux kernel
configuration item ``CONFIG_LOCALVERSION``, which is visible through
the ``uname`` command. Here is an example that shows the extension
assuming it was set as previously shown::
$ uname -r
3.7.0-rc8-custom
:term:`LOG_DIR`
Specifies the directory to which the OpenEmbedded build system writes
overall log files. The default directory is ``${TMPDIR}/log``.
For the directory containing logs specific to each task, see the
:term:`T` variable.
:term:`MACHINE`
Specifies the target device for which the image is built. You define
:term:`MACHINE` in the ``local.conf`` file found in the
:term:`Build Directory`. By default, :term:`MACHINE` is set to
"qemux86", which is an x86-based architecture machine to be emulated
using QEMU::
MACHINE ?= "qemux86"
The variable corresponds to a machine configuration file of the same
name, through which machine-specific configurations are set. Thus,
when :term:`MACHINE` is set to "qemux86", the corresponding
``qemux86.conf`` machine configuration file can be found in
the :term:`Source Directory` in
``meta/conf/machine``.
The list of machines supported by the Yocto Project as shipped
include the following::
MACHINE ?= "qemuarm"
MACHINE ?= "qemuarm64"
MACHINE ?= "qemumips"
MACHINE ?= "qemumips64"
MACHINE ?= "qemuppc"
MACHINE ?= "qemux86"
MACHINE ?= "qemux86-64"
MACHINE ?= "genericx86"
MACHINE ?= "genericx86-64"
MACHINE ?= "beaglebone"
MACHINE ?= "edgerouter"
The last five are Yocto Project reference hardware
boards, which are provided in the ``meta-yocto-bsp`` layer.
.. note::
Adding additional Board Support Package (BSP) layers to your
configuration adds new possible settings for :term:`MACHINE`.
:term:`MACHINE_ARCH`
Specifies the name of the machine-specific architecture. This
variable is set automatically from :term:`MACHINE` or
:term:`TUNE_PKGARCH`. You should not hand-edit
the :term:`MACHINE_ARCH` variable.
:term:`MACHINE_ESSENTIAL_EXTRA_RDEPENDS`
A list of required machine-specific packages to install as part of
the image being built. The build process depends on these packages
being present. Furthermore, because this is a "machine-essential"
variable, the list of packages are essential for the machine to boot.
The impact of this variable affects images based on
``packagegroup-core-boot``, including the ``core-image-minimal``
image.
This variable is similar to the
:term:`MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS` variable with the exception
that the image being built has a build dependency on the variable's
list of packages. In other words, the image will not build if a file
in this list is not found.
As an example, suppose the machine for which you are building
requires ``example-init`` to be run during boot to initialize the
hardware. In this case, you would use the following in the machine's
``.conf`` configuration file::
MACHINE_ESSENTIAL_EXTRA_RDEPENDS += "example-init"
:term:`MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS`
A list of recommended machine-specific packages to install as part of
the image being built. The build process does not depend on these
packages being present. However, because this is a
"machine-essential" variable, the list of packages are essential for
the machine to boot. The impact of this variable affects images based
on ``packagegroup-core-boot``, including the ``core-image-minimal``
image.
This variable is similar to the :term:`MACHINE_ESSENTIAL_EXTRA_RDEPENDS`
variable with the exception that the image being built does not have
a build dependency on the variable's list of packages. In other
words, the image will still build if a package in this list is not
found. Typically, this variable is used to handle essential kernel
modules, whose functionality may be selected to be built into the
kernel rather than as a module, in which case a package will not be
produced.
Consider an example where you have a custom kernel where a specific
touchscreen driver is required for the machine to be usable. However,
the driver can be built as a module or into the kernel depending on
the kernel configuration. If the driver is built as a module, you
want it to be installed. But, when the driver is built into the
kernel, you still want the build to succeed. This variable sets up a
"recommends" relationship so that in the latter case, the build will
not fail due to the missing package. To accomplish this, assuming the
package for the module was called ``kernel-module-ab123``, you would
use the following in the machine's ``.conf`` configuration file::
MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS += "kernel-module-ab123"
.. note::
In this example, the ``kernel-module-ab123`` recipe needs to
explicitly set its :term:`PACKAGES` variable to ensure that BitBake
does not use the kernel recipe's :term:`PACKAGES_DYNAMIC` variable to
satisfy the dependency.
Some examples of these machine essentials are flash, screen,
keyboard, mouse, or touchscreen drivers (depending on the machine).
:term:`MACHINE_EXTRA_RDEPENDS`
A list of machine-specific packages to install as part of the image
being built that are not essential for the machine to boot. However,
the build process for more fully-featured images depends on the
packages being present.
This variable affects all images based on ``packagegroup-base``,
which does not include the ``core-image-minimal`` or
``core-image-full-cmdline`` images.
The variable is similar to the :term:`MACHINE_EXTRA_RRECOMMENDS` variable
with the exception that the image being built has a build dependency
on the variable's list of packages. In other words, the image will
not build if a file in this list is not found.
An example is a machine that has WiFi capability but is not essential
for the machine to boot the image. However, if you are building a
more fully-featured image, you want to enable the WiFi. The package
containing the firmware for the WiFi hardware is always expected to
exist, so it is acceptable for the build process to depend upon
finding the package. In this case, assuming the package for the
firmware was called ``wifidriver-firmware``, you would use the
following in the ``.conf`` file for the machine::
MACHINE_EXTRA_RDEPENDS += "wifidriver-firmware"
:term:`MACHINE_EXTRA_RRECOMMENDS`
A list of machine-specific packages to install as part of the image
being built that are not essential for booting the machine. The image
being built has no build dependency on this list of packages.
This variable affects only images based on ``packagegroup-base``,
which does not include the ``core-image-minimal`` or
``core-image-full-cmdline`` images.
This variable is similar to the :term:`MACHINE_EXTRA_RDEPENDS` variable
with the exception that the image being built does not have a build
dependency on the variable's list of packages. In other words, the
image will build if a file in this list is not found.
An example is a machine that has WiFi capability but is not essential
For the machine to boot the image. However, if you are building a
more fully-featured image, you want to enable WiFi. In this case, the
package containing the WiFi kernel module will not be produced if the
WiFi driver is built into the kernel, in which case you still want
the build to succeed instead of failing as a result of the package
not being found. To accomplish this, assuming the package for the
module was called ``kernel-module-examplewifi``, you would use the
following in the ``.conf`` file for the machine::
MACHINE_EXTRA_RRECOMMENDS += "kernel-module-examplewifi"
:term:`MACHINE_FEATURES`
Specifies the list of hardware features the
:term:`MACHINE` is capable of supporting. For related
information on enabling features, see the
:term:`DISTRO_FEATURES`,
:term:`COMBINED_FEATURES`, and
:term:`IMAGE_FEATURES` variables.
For a list of hardware features supported by the Yocto Project as
shipped, see the ":ref:`ref-features-machine`" section.
:term:`MACHINE_FEATURES_BACKFILL`
Features to be added to :term:`MACHINE_FEATURES` if not also present in
:term:`MACHINE_FEATURES_BACKFILL_CONSIDERED`.
This variable is set in the ``meta/conf/bitbake.conf`` file. It is
not intended to be user-configurable. It is best to just reference
the variable to see which machine features are being backfilled for
all machine configurations. See the ":ref:`ref-features-backfill`"
section for more information.
:term:`MACHINE_FEATURES_BACKFILL_CONSIDERED`
Features from :term:`MACHINE_FEATURES_BACKFILL` that should not be
backfilled (i.e. added to :term:`MACHINE_FEATURES`) during the build. See
the ":ref:`ref-features-backfill`" section for more information.
:term:`MACHINEOVERRIDES`
A colon-separated list of overrides that apply to the current
machine. By default, this list includes the value of
:term:`MACHINE`.
You can extend :term:`MACHINEOVERRIDES` to add extra overrides that
should apply to a machine. For example, all machines emulated in QEMU
(e.g. ``qemuarm``, ``qemux86``, and so forth) include a file named
``meta/conf/machine/include/qemu.inc`` that prepends the following
override to :term:`MACHINEOVERRIDES`::
MACHINEOVERRIDES =. "qemuall:"
This
override allows variables to be overridden for all machines emulated
in QEMU, like in the following example from the ``connman-conf``
recipe::
SRC_URI:append:qemuall = " file://wired.config \
file://wired-setup \
"
The underlying mechanism behind
:term:`MACHINEOVERRIDES` is simply that it is included in the default
value of :term:`OVERRIDES`.
:term:`MAINTAINER`
The email address of the distribution maintainer.
:term:`METADATA_BRANCH`
The branch currently checked out for the OpenEmbedded-Core layer (path
determined by :term:`COREBASE`).
:term:`METADATA_REVISION`
The revision currently checked out for the OpenEmbedded-Core layer (path
determined by :term:`COREBASE`).
:term:`MIME_XDG_PACKAGES`
The current implementation of the :ref:`ref-classes-mime-xdg`
class cannot detect ``.desktop`` files installed through absolute
symbolic links. Use this setting to make the class create post-install
and post-remove scripts for these packages anyway, to invoke the
``update-destop-database`` command.
:term:`MIRRORS`
Specifies additional paths from which the OpenEmbedded build system
gets source code. When the build system searches for source code, it
first tries the local download directory. If that location fails, the
build system tries locations defined by
:term:`PREMIRRORS`, the upstream source, and then
locations specified by :term:`MIRRORS` in that order.
Assuming your distribution (:term:`DISTRO`) is "poky",
the default value for :term:`MIRRORS` is defined in the
``conf/distro/poky.conf`` file in the ``meta-poky`` Git repository.
:term:`MLPREFIX`
Specifies a prefix has been added to :term:`PN` to create a
special version of a recipe or package (i.e. a Multilib version). The
variable is used in places where the prefix needs to be added to or
removed from a the name (e.g. the :term:`BPN` variable).
:term:`MLPREFIX` gets set when a prefix has been added to :term:`PN`.
.. note::
The "ML" in :term:`MLPREFIX` stands for "MultiLib". This representation
is historical and comes from a time when ":ref:`ref-classes-nativesdk`"
was a suffix rather than a prefix on the recipe name. When
":ref:`ref-classes-nativesdk`" was turned into a prefix, it made sense
to set :term:`MLPREFIX` for it as well.
To help understand when :term:`MLPREFIX` might be needed, consider when
:term:`BBCLASSEXTEND` is used to provide a :ref:`ref-classes-nativesdk`
version of a recipe in addition to the target version. If that recipe
declares build-time dependencies on tasks in other recipes by using
:term:`DEPENDS`, then a dependency on "foo" will automatically get
rewritten to a dependency on "nativesdk-foo". However, dependencies like
the following will not get rewritten automatically::
do_foo[depends] += "recipe:do_foo"
If you want such a dependency to also get transformed, you can do the
following::
do_foo[depends] += "${MLPREFIX}recipe:do_foo"
:term:`module_autoload`
This variable has been replaced by the :term:`KERNEL_MODULE_AUTOLOAD`
variable. You should replace all occurrences of :term:`module_autoload`
with additions to :term:`KERNEL_MODULE_AUTOLOAD`, for example::
module_autoload_rfcomm = "rfcomm"
should now be replaced with::
KERNEL_MODULE_AUTOLOAD += "rfcomm"
See the :term:`KERNEL_MODULE_AUTOLOAD` variable for more information.
:term:`module_conf`
Specifies `modprobe.d <https://linux.die.net/man/5/modprobe.d>`__
syntax lines for inclusion in the ``/etc/modprobe.d/modname.conf``
file.
You can use this variable anywhere that it can be recognized by the
kernel recipe or out-of-tree kernel module recipe (e.g. a machine
configuration file, a distribution configuration file, an append file
for the recipe, or the recipe itself). If you use this variable, you
must also be sure to list the module name in the
:term:`KERNEL_MODULE_PROBECONF`
variable.
Here is the general syntax::
module_conf_module_name = "modprobe.d-syntax"
You must use the kernel module name override.
Run ``man modprobe.d`` in the shell to find out more information on
the exact syntax you want to provide with :term:`module_conf`.
Including :term:`module_conf` causes the OpenEmbedded build system to
populate the ``/etc/modprobe.d/modname.conf`` file with
``modprobe.d`` syntax lines. Here is an example that adds the options
``arg1`` and ``arg2`` to a module named ``mymodule``::
module_conf_mymodule = "options mymodule arg1=val1 arg2=val2"
For information on how to specify kernel modules to auto-load on
boot, see the :term:`KERNEL_MODULE_AUTOLOAD` variable.
:term:`MODULE_TARBALL_DEPLOY`
Controls creation of the ``modules-*.tgz`` file. Set this variable to
"0" to disable creation of this file, which contains all of the
kernel modules resulting from a kernel build.
:term:`MODULE_TARBALL_LINK_NAME`
The link name of the kernel module tarball. This variable is set in
the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as follows::
MODULE_TARBALL_LINK_NAME ?= "${KERNEL_ARTIFACT_LINK_NAME}"
The value
of the ``KERNEL_ARTIFACT_LINK_NAME`` variable, which is set in the
same file, has the following value::
KERNEL_ARTIFACT_LINK_NAME ?= "${MACHINE}"
See the :term:`MACHINE` variable for additional information.
:term:`MODULE_TARBALL_NAME`
The base name of the kernel module tarball. This variable is set in
the ``meta/classes-recipe/kernel-artifact-names.bbclass`` file as follows::
MODULE_TARBALL_NAME ?= "${KERNEL_ARTIFACT_NAME}"
The value of the :term:`KERNEL_ARTIFACT_NAME` variable,
which is set in the same file, has the following value::
KERNEL_ARTIFACT_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
:term:`MOUNT_BASE`
On non-systemd systems (where ``udev-extraconf`` is being used),
specifies the base directory for auto-mounting filesystems. The
default value is "/run/media".
:term:`MULTIMACH_TARGET_SYS`
Uniquely identifies the type of the target system for which packages
are being built. This variable allows output for different types of
target systems to be put into different subdirectories of the same
output directory.
The default value of this variable is::
${PACKAGE_ARCH}${TARGET_VENDOR}-${TARGET_OS}
Some classes (e.g. :ref:`ref-classes-cross-canadian`) modify the
:term:`MULTIMACH_TARGET_SYS` value.
See the :term:`STAMP` variable for an example. See the
:term:`STAGING_DIR_TARGET` variable for more information.
:term:`NATIVELSBSTRING`
A string identifying the host distribution. Strings consist of the
host distributor ID followed by the release, as reported by the
``lsb_release`` tool or as read from ``/etc/lsb-release``. For
example, when running a build on Ubuntu 12.10, the value is
"Ubuntu-12.10". If this information is unable to be determined, the
value resolves to "Unknown".
This variable is used by default to isolate native shared state
packages for different distributions (e.g. to avoid problems with
``glibc`` version incompatibilities). Additionally, the variable is
checked against
:term:`SANITY_TESTED_DISTROS` if that
variable is set.
:term:`NM`
The minimal command and arguments to run ``nm``.
:term:`NO_GENERIC_LICENSE`
Avoids QA errors when you use a non-common, non-CLOSED license in a
recipe. There are packages, such as the linux-firmware package, with many
licenses that are not in any way common. Also, new licenses are added
occasionally to avoid introducing a lot of common license files,
which are only applicable to a specific package.
:term:`NO_GENERIC_LICENSE` is used to allow copying a license that does
not exist in common licenses.
The following example shows how to add :term:`NO_GENERIC_LICENSE` to a
recipe::
NO_GENERIC_LICENSE[license_name] = "license_file_in_fetched_source"
Here is an example that
uses the ``LICENSE.Abilis.txt`` file as the license from the fetched
source::
NO_GENERIC_LICENSE[Firmware-Abilis] = "LICENSE.Abilis.txt"
:term:`NO_RECOMMENDATIONS`
Prevents installation of all "recommended-only" packages.
Recommended-only packages are packages installed only through the
:term:`RRECOMMENDS` variable). Setting the
:term:`NO_RECOMMENDATIONS` variable to "1" turns this feature on::
NO_RECOMMENDATIONS = "1"
You can set this variable globally in your ``local.conf`` file or you
can attach it to a specific image recipe by using the recipe name
override::
NO_RECOMMENDATIONS:pn-target_image = "1"
It is important to realize that if you choose to not install packages
using this variable and some other packages are dependent on them
(i.e. listed in a recipe's :term:`RDEPENDS`
variable), the OpenEmbedded build system ignores your request and
will install the packages to avoid dependency errors.
.. note::
Some recommended packages might be required for certain system
functionality, such as kernel modules. It is up to you to add
packages with the :term:`IMAGE_INSTALL` variable.
This variable is only supported when using the IPK and RPM
packaging backends. DEB is not supported.
See the :term:`BAD_RECOMMENDATIONS` and
the :term:`PACKAGE_EXCLUDE` variables for
related information.
:term:`NOAUTOPACKAGEDEBUG`
Disables auto package from splitting ``.debug`` files. If a recipe
requires ``FILES:${PN}-dbg`` to be set manually, the
:term:`NOAUTOPACKAGEDEBUG` can be defined allowing you to define the
content of the debug package. For example::
NOAUTOPACKAGEDEBUG = "1"
FILES:${PN}-dev = "${includedir}/${QT_DIR_NAME}/Qt/*"
FILES:${PN}-dbg = "/usr/src/debug/"
FILES:${QT_BASE_NAME}-demos-doc = "${docdir}/${QT_DIR_NAME}/qch/qt.qch"
:term:`NON_MULTILIB_RECIPES`
A list of recipes that should not be built for multilib. OE-Core's
``multilib.conf`` file defines a reasonable starting point for this
list with::
NON_MULTILIB_RECIPES = "grub grub-efi make-mod-scripts ovmf u-boot"
:term:`OBJCOPY`
The minimal command and arguments to run ``objcopy``.
:term:`OBJDUMP`
The minimal command and arguments to run ``objdump``.
:term:`OE_BINCONFIG_EXTRA_MANGLE`
When inheriting the :ref:`ref-classes-binconfig` class,
this variable specifies additional arguments passed to the "sed"
command. The sed command alters any paths in configuration scripts
that have been set up during compilation. Inheriting this class
results in all paths in these scripts being changed to point into the
``sysroots/`` directory so that all builds that use the script will
use the correct directories for the cross compiling layout.
See the ``meta/classes-recipe/binconfig.bbclass`` in the
:term:`Source Directory` for details on how this class
applies these additional sed command arguments.
:term:`OE_IMPORTS`
An internal variable used to tell the OpenEmbedded build system what
Python modules to import for every Python function run by the system.
.. note::
Do not set this variable. It is for internal use only.
:term:`OE_INIT_ENV_SCRIPT`
The name of the build environment setup script for the purposes of
setting up the environment within the extensible SDK. The default
value is "oe-init-build-env".
If you use a custom script to set up your build environment, set the
:term:`OE_INIT_ENV_SCRIPT` variable to its name.
:term:`OE_TERMINAL`
Controls how the OpenEmbedded build system spawns interactive
terminals on the host development system (e.g. using the BitBake
command with the ``-c devshell`` command-line option). For more
information, see the ":ref:`dev-manual/development-shell:using a development shell`" section in
the Yocto Project Development Tasks Manual.
You can use the following values for the :term:`OE_TERMINAL` variable:
- auto
- gnome
- xfce
- rxvt
- screen
- konsole
- none
:term:`OEROOT`
The directory from which the top-level build environment setup script
is sourced. The Yocto Project provides a top-level build environment
setup script: :ref:`structure-core-script`. When you run this
script, the :term:`OEROOT` variable resolves to the directory that
contains the script.
For additional information on how this variable is used, see the
initialization script.
:term:`OLDEST_KERNEL`
Declares the oldest version of the Linux kernel that the produced
binaries must support. This variable is passed into the build of the
Embedded GNU C Library (``glibc``).
The default for this variable comes from the
``meta/conf/bitbake.conf`` configuration file. You can override this
default by setting the variable in a custom distribution
configuration file.
:term:`OVERLAYFS_ETC_DEVICE`
When the :ref:`ref-classes-overlayfs-etc` class is
inherited, specifies the device to be mounted for the read/write
layer of ``/etc``. There is no default, so you must set this if you
wish to enable :ref:`ref-classes-overlayfs-etc`, for
example, assuming ``/dev/mmcblk0p2`` was the desired device::
OVERLAYFS_ETC_DEVICE = "/dev/mmcblk0p2"
:term:`OVERLAYFS_ETC_EXPOSE_LOWER`
When the :ref:`ref-classes-overlayfs-etc` class is
inherited, if set to "1" then a read-only access to the original
``/etc`` content will be provided as a ``lower/`` subdirectory of
:term:`OVERLAYFS_ETC_MOUNT_POINT`. The default value is "0".
:term:`OVERLAYFS_ETC_FSTYPE`
When the :ref:`ref-classes-overlayfs-etc` class is
inherited, specifies the file system type for the read/write
layer of ``/etc``. There is no default, so you must set this if you
wish to enable :ref:`ref-classes-overlayfs-etc`,
for example, assuming the file system is ext4::
OVERLAYFS_ETC_FSTYPE = "ext4"
:term:`OVERLAYFS_ETC_MOUNT_OPTIONS`
When the :ref:`ref-classes-overlayfs-etc` class is
inherited, specifies the mount options for the read-write layer.
The default value is "defaults".
:term:`OVERLAYFS_ETC_MOUNT_POINT`
When the :ref:`ref-classes-overlayfs-etc` class is
inherited, specifies the parent mount path for the filesystem layers.
There is no default, so you must set this if you wish to enable
:ref:`ref-classes-overlayfs-etc`, for example if the desired path is
"/data"::
OVERLAYFS_ETC_MOUNT_POINT = "/data"
:term:`OVERLAYFS_ETC_USE_ORIG_INIT_NAME`
When the :ref:`ref-classes-overlayfs-etc` class is inherited, controls
how the generated init will be named. For more information, see the
:ref:`ref-classes-overlayfs-etc` class documentation. The default value
is "1".
:term:`OVERLAYFS_MOUNT_POINT`
When inheriting the :ref:`ref-classes-overlayfs` class,
specifies mount point(s) to be used. For example::
OVERLAYFS_MOUNT_POINT[data] = "/data"
The assumes you have a ``data.mount`` systemd unit defined elsewhere in
your BSP (e.g. in ``systemd-machine-units`` recipe) and it is installed
into the image. For more information see :ref:`ref-classes-overlayfs`.
.. note::
Although the :ref:`ref-classes-overlayfs` class is
inherited by individual recipes, :term:`OVERLAYFS_MOUNT_POINT`
should be set in your machine configuration.
:term:`OVERLAYFS_QA_SKIP`
When inheriting the :ref:`ref-classes-overlayfs` class,
provides the ability to disable QA checks for particular overlayfs
mounts. For example::
OVERLAYFS_QA_SKIP[data] = "mount-configured"
.. note::
Although the :ref:`ref-classes-overlayfs` class is
inherited by individual recipes, :term:`OVERLAYFS_QA_SKIP`
should be set in your machine configuration.
:term:`OVERLAYFS_WRITABLE_PATHS`
When inheriting the :ref:`ref-classes-overlayfs` class,
specifies writable paths used at runtime for the recipe. For
example::
OVERLAYFS_WRITABLE_PATHS[data] = "/usr/share/my-custom-application"
:term:`OVERRIDES`
A colon-separated list of overrides that currently apply. Overrides
are a BitBake mechanism that allows variables to be selectively
overridden at the end of parsing. The set of overrides in
:term:`OVERRIDES` represents the "state" during building, which includes
the current recipe being built, the machine for which it is being
built, and so forth.
As an example, if the string "an-override" appears as an element in
the colon-separated list in :term:`OVERRIDES`, then the following
assignment will override ``FOO`` with the value "overridden" at the
end of parsing::
FOO:an-override = "overridden"
See the
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:conditional syntax (overrides)`"
section in the BitBake User Manual for more information on the
overrides mechanism.
The default value of :term:`OVERRIDES` includes the values of the
:term:`CLASSOVERRIDE`,
:term:`MACHINEOVERRIDES`, and
:term:`DISTROOVERRIDES` variables. Another
important override included by default is ``pn-${PN}``. This override
allows variables to be set for a single recipe within configuration
(``.conf``) files. Here is an example::
FOO:pn-myrecipe = "myrecipe-specific value"
.. note::
An easy way to see what overrides apply is to search for :term:`OVERRIDES`
in the output of the ``bitbake -e`` command. See the
":ref:`dev-manual/debugging:viewing variable values`" section in the Yocto
Project Development Tasks Manual for more information.
:term:`P`
The recipe name and version. :term:`P` is comprised of the following::
${PN}-${PV}
:term:`P4DIR`
See :term:`bitbake:P4DIR` in the BitBake manual.
:term:`PACKAGE_ADD_METADATA`
This variable defines additional metadata to add to packages.
You may find you need to inject additional metadata into packages.
This variable allows you to do that by setting the injected data as
the value. Multiple fields can be added by splitting the content with
the literal separator "\n".
The suffixes '_IPK', '_DEB', or '_RPM' can be applied to the variable
to do package type specific settings. It can also be made package
specific by using the package name as a suffix.
You can find out more about applying this variable in the
":ref:`dev-manual/packages:adding custom metadata to packages`"
section in the Yocto Project Development Tasks Manual.
:term:`PACKAGE_ARCH`
The architecture of the resulting package or packages.
By default, the value of this variable is set to
:term:`TUNE_PKGARCH` when building for the
target, :term:`BUILD_ARCH` when building for the
build host, and "${SDK_ARCH}-${SDKPKGSUFFIX}" when building for the
SDK.
.. note::
See :term:`SDK_ARCH` for more information.
However, if your recipe's output packages are built specific to the
target machine rather than generally for the architecture of the
machine, you should set :term:`PACKAGE_ARCH` to the value of
:term:`MACHINE_ARCH` in the recipe as follows::
PACKAGE_ARCH = "${MACHINE_ARCH}"
:term:`PACKAGE_ARCHS`
Specifies a list of architectures compatible with the target machine.
This variable is set automatically and should not normally be
hand-edited. Entries are separated using spaces and listed in order
of priority. The default value for :term:`PACKAGE_ARCHS` is "all any
noarch ${PACKAGE_EXTRA_ARCHS} ${MACHINE_ARCH}".
:term:`PACKAGE_BEFORE_PN`
Enables easily adding packages to :term:`PACKAGES` before ``${PN}`` so
that those added packages can pick up files that would normally be
included in the default package.
:term:`PACKAGE_CLASSES`
This variable, which is set in the ``local.conf`` configuration file
found in the ``conf`` folder of the
:term:`Build Directory`, specifies the package manager the
OpenEmbedded build system uses when packaging data.
You can provide one or more of the following arguments for the
variable::
PACKAGE_CLASSES ?= "package_rpm package_deb package_ipk package_tar"
.. note::
While it is a legal option, the :ref:`ref-classes-package_tar`
class has limited functionality due to no support for package
dependencies by that backend. Therefore, it is recommended that
you do not use it.
The build system uses only the first argument in the list as the
package manager when creating your image or SDK. However, packages
will be created using any additional packaging classes you specify.
For example, if you use the following in your ``local.conf`` file::
PACKAGE_CLASSES ?= "package_ipk"
The OpenEmbedded build system uses
the IPK package manager to create your image or SDK.
For information on packaging and build performance effects as a
result of the package manager in use, see the
":ref:`ref-classes-package`" section.
:term:`PACKAGE_DEBUG_SPLIT_STYLE`
Determines how to split up and package debug and source information
when creating debugging packages to be used with the GNU Project
Debugger (GDB). In general, based on the value of this variable,
you can combine the source and debug info in a single package,
you can break out the source into a separate package that can be
installed independently, or you can choose to not have the source
packaged at all.
The possible values of :term:`PACKAGE_DEBUG_SPLIT_STYLE` variable:
- "``.debug``": All debugging and source info is placed in a single
``*-dbg`` package; debug symbol files are placed next to the
binary in a ``.debug`` directory so that, if a binary is installed
into ``/bin``, the corresponding debug symbol file is installed
in ``/bin/.debug``. Source files are installed in the same ``*-dbg``
package under ``/usr/src/debug``.
- "``debug-file-directory``": As above, all debugging and source info
is placed in a single ``*-dbg`` package; debug symbol files are
placed entirely under the directory ``/usr/lib/debug`` and separated
by the path from where the binary is installed, so that if a binary
is installed in ``/bin``, the corresponding debug symbols are installed
in ``/usr/lib/debug/bin``, and so on. As above, source is installed
in the same package under ``/usr/src/debug``.
- "``debug-with-srcpkg``": Debugging info is placed in the standard
``*-dbg`` package as with the ``.debug`` value, while source is
placed in a separate ``*-src`` package, which can be installed
independently. This is the default setting for this variable,
as defined in Poky's ``bitbake.conf`` file.
- "``debug-without-src``": The same behavior as with the ``.debug``
setting, but no source is packaged at all.
.. note::
Much of the above package splitting can be overridden via
use of the :term:`INHIBIT_PACKAGE_DEBUG_SPLIT` variable.
You can find out more about debugging using GDB by reading the
":ref:`dev-manual/debugging:debugging with the gnu project debugger (gdb) remotely`" section
in the Yocto Project Development Tasks Manual.
:term:`PACKAGE_EXCLUDE`
Lists packages that should not be installed into an image. For
example::
PACKAGE_EXCLUDE = "package_name package_name package_name ..."
You can set this variable globally in your ``local.conf`` file or you
can attach it to a specific image recipe by using the recipe name
override::
PACKAGE_EXCLUDE:pn-target_image = "package_name"
If you choose to not install a package using this variable and some
other package is dependent on it (i.e. listed in a recipe's
:term:`RDEPENDS` variable), the OpenEmbedded build
system generates a fatal installation error. Because the build system
halts the process with a fatal error, you can use the variable with
an iterative development process to remove specific components from a
system.
This variable is supported only when using the IPK and RPM
packaging backends. DEB is not supported.
See the :term:`NO_RECOMMENDATIONS` and the
:term:`BAD_RECOMMENDATIONS` variables for
related information.
:term:`PACKAGE_EXCLUDE_COMPLEMENTARY`
Prevents specific packages from being installed when you are
installing complementary packages.
You might find that you want to prevent installing certain packages
when you are installing complementary packages. For example, if you
are using :term:`IMAGE_FEATURES` to install
``dev-pkgs``, you might not want to install all packages from a
particular multilib. If you find yourself in this situation, you can
use the :term:`PACKAGE_EXCLUDE_COMPLEMENTARY` variable to specify regular
expressions to match the packages you want to exclude.
:term:`PACKAGE_EXTRA_ARCHS`
Specifies the list of architectures compatible with the device CPU.
This variable is useful when you build for several different devices
that use miscellaneous processors such as XScale and ARM926-EJS.
:term:`PACKAGE_FEED_ARCHS`
Optionally specifies the package architectures used as part of the
package feed URIs during the build. When used, the
:term:`PACKAGE_FEED_ARCHS` variable is appended to the final package feed
URI, which is constructed using the
:term:`PACKAGE_FEED_URIS` and
:term:`PACKAGE_FEED_BASE_PATHS`
variables.
.. note::
You can use the :term:`PACKAGE_FEED_ARCHS`
variable to allow specific package architectures. If you do
not need to allow specific architectures, which is a common
case, you can omit this variable. Omitting the variable results in
all available architectures for the current machine being included
into remote package feeds.
Consider the following example where the :term:`PACKAGE_FEED_URIS`,
:term:`PACKAGE_FEED_BASE_PATHS`, and :term:`PACKAGE_FEED_ARCHS` variables are
defined in your ``local.conf`` file::
PACKAGE_FEED_URIS = "https://example.com/packagerepos/release \
https://example.com/packagerepos/updates"
PACKAGE_FEED_BASE_PATHS = "rpm rpm-dev"
PACKAGE_FEED_ARCHS = "all core2-64"
Given these settings, the resulting package feeds are as follows:
.. code-block:: none
https://example.com/packagerepos/release/rpm/all
https://example.com/packagerepos/release/rpm/core2-64
https://example.com/packagerepos/release/rpm-dev/all
https://example.com/packagerepos/release/rpm-dev/core2-64
https://example.com/packagerepos/updates/rpm/all
https://example.com/packagerepos/updates/rpm/core2-64
https://example.com/packagerepos/updates/rpm-dev/all
https://example.com/packagerepos/updates/rpm-dev/core2-64
:term:`PACKAGE_FEED_BASE_PATHS`
Specifies the base path used when constructing package feed URIs. The
:term:`PACKAGE_FEED_BASE_PATHS` variable makes up the middle portion of a
package feed URI used by the OpenEmbedded build system. The base path
lies between the :term:`PACKAGE_FEED_URIS`
and :term:`PACKAGE_FEED_ARCHS` variables.
Consider the following example where the :term:`PACKAGE_FEED_URIS`,
:term:`PACKAGE_FEED_BASE_PATHS`, and :term:`PACKAGE_FEED_ARCHS` variables are
defined in your ``local.conf`` file::
PACKAGE_FEED_URIS = "https://example.com/packagerepos/release \
https://example.com/packagerepos/updates"
PACKAGE_FEED_BASE_PATHS = "rpm rpm-dev"
PACKAGE_FEED_ARCHS = "all core2-64"
Given these settings, the resulting package feeds are as follows:
.. code-block:: none
https://example.com/packagerepos/release/rpm/all
https://example.com/packagerepos/release/rpm/core2-64
https://example.com/packagerepos/release/rpm-dev/all
https://example.com/packagerepos/release/rpm-dev/core2-64
https://example.com/packagerepos/updates/rpm/all
https://example.com/packagerepos/updates/rpm/core2-64
https://example.com/packagerepos/updates/rpm-dev/all
https://example.com/packagerepos/updates/rpm-dev/core2-64
:term:`PACKAGE_FEED_URIS`
Specifies the front portion of the package feed URI used by the
OpenEmbedded build system. Each final package feed URI is comprised
of :term:`PACKAGE_FEED_URIS`,
:term:`PACKAGE_FEED_BASE_PATHS`, and
:term:`PACKAGE_FEED_ARCHS` variables.
Consider the following example where the :term:`PACKAGE_FEED_URIS`,
:term:`PACKAGE_FEED_BASE_PATHS`, and :term:`PACKAGE_FEED_ARCHS` variables are
defined in your ``local.conf`` file::
PACKAGE_FEED_URIS = "https://example.com/packagerepos/release \
https://example.com/packagerepos/updates"
PACKAGE_FEED_BASE_PATHS = "rpm rpm-dev"
PACKAGE_FEED_ARCHS = "all core2-64"
Given these settings, the resulting package feeds are as follows:
.. code-block:: none
https://example.com/packagerepos/release/rpm/all
https://example.com/packagerepos/release/rpm/core2-64
https://example.com/packagerepos/release/rpm-dev/all
https://example.com/packagerepos/release/rpm-dev/core2-64
https://example.com/packagerepos/updates/rpm/all
https://example.com/packagerepos/updates/rpm/core2-64
https://example.com/packagerepos/updates/rpm-dev/all
https://example.com/packagerepos/updates/rpm-dev/core2-64
:term:`PACKAGE_INSTALL`
The final list of packages passed to the package manager for
installation into the image.
Because the package manager controls actual installation of all
packages, the list of packages passed using :term:`PACKAGE_INSTALL` is
not the final list of packages that are actually installed. This
variable is internal to the image construction code. Consequently, in
general, you should use the
:term:`IMAGE_INSTALL` variable to specify
packages for installation. The exception to this is when working with
the :ref:`core-image-minimal-initramfs <ref-manual/images:images>`
image. When working with an initial RAM filesystem (:term:`Initramfs`) image,
use the :term:`PACKAGE_INSTALL` variable. For information on creating an
:term:`Initramfs`, see the ":ref:`dev-manual/building:building an initial ram filesystem (Initramfs) image`" section
in the Yocto Project Development Tasks Manual.
:term:`PACKAGE_INSTALL_ATTEMPTONLY`
Specifies a list of packages the OpenEmbedded build system attempts
to install when creating an image. If a listed package fails to
install, the build system does not generate an error. This variable
is generally not user-defined.
:term:`PACKAGE_PREPROCESS_FUNCS`
Specifies a list of functions run to pre-process the
:term:`PKGD` directory prior to splitting the files out
to individual packages.
:term:`PACKAGE_WRITE_DEPS`
Specifies a list of dependencies for post-installation and
pre-installation scripts on native/cross tools. If your
post-installation or pre-installation script can execute at root filesystem
creation time rather than on the target but depends on a native tool
in order to execute, you need to list the tools in
:term:`PACKAGE_WRITE_DEPS`.
For information on running post-installation scripts, see the
":ref:`dev-manual/new-recipe:post-installation scripts`"
section in the Yocto Project Development Tasks Manual.
:term:`PACKAGECONFIG`
This variable provides a means of enabling or disabling features of a
recipe on a per-recipe basis. :term:`PACKAGECONFIG` blocks are defined in
recipes when you specify features and then arguments that define
feature behaviors. Here is the basic block structure (broken over
multiple lines for readability)::
PACKAGECONFIG ??= "f1 f2 f3 ..."
PACKAGECONFIG[f1] = "\
--with-f1, \
--without-f1, \
build-deps-for-f1, \
runtime-deps-for-f1, \
runtime-recommends-for-f1, \
packageconfig-conflicts-for-f1"
PACKAGECONFIG[f2] = "\
... and so on and so on ...
The :term:`PACKAGECONFIG` variable itself specifies a space-separated
list of the features to enable. Following the features, you can
determine the behavior of each feature by providing up to six
order-dependent arguments, which are separated by commas. You can
omit any argument you like but must retain the separating commas. The
order is important and specifies the following:
#. Extra arguments that should be added to the configure script
argument list (:term:`EXTRA_OECONF` or
:term:`PACKAGECONFIG_CONFARGS`) if
the feature is enabled.
#. Extra arguments that should be added to :term:`EXTRA_OECONF` or
:term:`PACKAGECONFIG_CONFARGS` if the feature is disabled.
#. Additional build dependencies (:term:`DEPENDS`)
that should be added if the feature is enabled.
#. Additional runtime dependencies (:term:`RDEPENDS`)
that should be added if the feature is enabled.
#. Additional runtime recommendations
(:term:`RRECOMMENDS`) that should be added if
the feature is enabled.
#. Any conflicting (that is, mutually exclusive) :term:`PACKAGECONFIG`
settings for this feature.
Consider the following :term:`PACKAGECONFIG` block taken from the
``librsvg`` recipe. In this example the feature is ``gtk``, which has
three arguments that determine the feature's behavior::
PACKAGECONFIG[gtk] = "--with-gtk3,--without-gtk3,gtk+3"
The
``--with-gtk3`` and ``gtk+3`` arguments apply only if the feature is
enabled. In this case, ``--with-gtk3`` is added to the configure
script argument list and ``gtk+3`` is added to :term:`DEPENDS`. On the
other hand, if the feature is disabled say through a ``.bbappend``
file in another layer, then the second argument ``--without-gtk3`` is
added to the configure script instead.
The basic :term:`PACKAGECONFIG` structure previously described holds true
regardless of whether you are creating a block or changing a block.
When creating a block, use the structure inside your recipe.
If you want to change an existing :term:`PACKAGECONFIG` block, you can do
so one of two ways:
- *Append file:* Create an append file named
``recipename.bbappend`` in your layer and override the value of
:term:`PACKAGECONFIG`. You can either completely override the
variable::
PACKAGECONFIG = "f4 f5"
Or, you can just append the variable::
PACKAGECONFIG:append = " f4"
- *Configuration file:* This method is identical to changing the
block through an append file except you edit your ``local.conf``
or ``mydistro.conf`` file. As with append files previously
described, you can either completely override the variable::
PACKAGECONFIG:pn-recipename = "f4 f5"
Or, you can just amend the variable::
PACKAGECONFIG:append:pn-recipename = " f4"
:term:`PACKAGECONFIG_CONFARGS`
A space-separated list of configuration options generated from the
:term:`PACKAGECONFIG` setting.
Classes such as :ref:`ref-classes-autotools` and :ref:`ref-classes-cmake`
use :term:`PACKAGECONFIG_CONFARGS` to pass :term:`PACKAGECONFIG` options
to ``configure`` and ``cmake``, respectively. If you are using
:term:`PACKAGECONFIG` but not a class that handles the
:ref:`ref-tasks-configure` task, then you need to use
:term:`PACKAGECONFIG_CONFARGS` appropriately.
:term:`PACKAGEGROUP_DISABLE_COMPLEMENTARY`
For recipes inheriting the :ref:`ref-classes-packagegroup` class, setting
:term:`PACKAGEGROUP_DISABLE_COMPLEMENTARY` to "1" specifies that the
normal complementary packages (i.e. ``-dev``, ``-dbg``, and so forth)
should not be automatically created by the ``packagegroup`` recipe,
which is the default behavior.
:term:`PACKAGES`
The list of packages the recipe creates. The default value is the
following::
${PN}-src ${PN}-dbg ${PN}-staticdev ${PN}-dev ${PN}-doc ${PN}-locale ${PACKAGE_BEFORE_PN} ${PN}
During packaging, the :ref:`ref-tasks-package` task
goes through :term:`PACKAGES` and uses the :term:`FILES`
variable corresponding to each package to assign files to the
package. If a file matches the :term:`FILES` variable for more than one
package in :term:`PACKAGES`, it will be assigned to the earliest
(leftmost) package.
Packages in the variable's list that are empty (i.e. where none of
the patterns in ``FILES:``\ pkg match any files installed by the
:ref:`ref-tasks-install` task) are not generated,
unless generation is forced through the
:term:`ALLOW_EMPTY` variable.
:term:`PACKAGES_DYNAMIC`
A promise that your recipe satisfies runtime dependencies for
optional modules that are found in other recipes.
:term:`PACKAGES_DYNAMIC` does not actually satisfy the dependencies, it
only states that they should be satisfied. For example, if a hard,
runtime dependency (:term:`RDEPENDS`) of another
package is satisfied at build time through the :term:`PACKAGES_DYNAMIC`
variable, but a package with the module name is never actually
produced, then the other package will be broken. Thus, if you attempt
to include that package in an image, you will get a dependency
failure from the packaging system during the
:ref:`ref-tasks-rootfs` task.
Typically, if there is a chance that such a situation can occur and
the package that is not created is valid without the dependency being
satisfied, then you should use :term:`RRECOMMENDS`
(a soft runtime dependency) instead of :term:`RDEPENDS`.
For an example of how to use the :term:`PACKAGES_DYNAMIC` variable when
you are splitting packages, see the
":ref:`dev-manual/packages:handling optional module packaging`"
section in the Yocto Project Development Tasks Manual.
:term:`PACKAGESPLITFUNCS`
Specifies a list of functions run to perform additional splitting of
files into individual packages. Recipes can either prepend to this
variable or prepend to the ``populate_packages`` function in order to
perform additional package splitting. In either case, the function
should set :term:`PACKAGES`,
:term:`FILES`, :term:`RDEPENDS` and
other packaging variables appropriately in order to perform the
desired splitting.
:term:`PARALLEL_MAKE`
Extra options passed to the build tool command (``make``,
``ninja`` or more specific build engines, like the Go language one)
during the :ref:`ref-tasks-compile` task, to specify parallel compilation
on the local build host. This variable is usually in the form "-j x",
where x represents the maximum number of parallel threads such engines
can run.
.. note::
For software compiled by ``make``, in order for :term:`PARALLEL_MAKE`
to be effective, ``make`` must be called with
``${``\ :term:`EXTRA_OEMAKE`\ ``}``. An easy
way to ensure this is to use the ``oe_runmake`` function.
By default, the OpenEmbedded build system automatically sets this
variable to be equal to the number of cores the build system uses.
.. note::
If the software being built experiences dependency issues during
the :ref:`ref-tasks-compile` task that result in race conditions, you can clear
the :term:`PARALLEL_MAKE` variable within the recipe as a workaround. For
information on addressing race conditions, see the
":ref:`dev-manual/debugging:debugging parallel make races`"
section in the Yocto Project Development Tasks Manual.
For single socket systems (i.e. one CPU), you should not have to
override this variable to gain optimal parallelism during builds.
However, if you have very large systems that employ multiple physical
CPUs, you might want to make sure the :term:`PARALLEL_MAKE` variable is
not set higher than "-j 20".
For more information on speeding up builds, see the
":ref:`dev-manual/speeding-up-build:speeding up a build`"
section in the Yocto Project Development Tasks Manual.
:term:`PARALLEL_MAKEINST`
Extra options passed to the build tool install command
(``make install``, ``ninja install`` or more specific ones)
during the :ref:`ref-tasks-install` task in order to specify
parallel installation. This variable defaults to the value of
:term:`PARALLEL_MAKE`.
.. note::
For software compiled by ``make``, in order for :term:`PARALLEL_MAKEINST`
to be effective, ``make`` must be called with
``${``\ :term:`EXTRA_OEMAKE`\ ``}``. An easy
way to ensure this is to use the ``oe_runmake`` function.
If the software being built experiences dependency issues during
the :ref:`ref-tasks-install` task that result in race conditions, you can
clear the :term:`PARALLEL_MAKEINST` variable within the recipe as a
workaround. For information on addressing race conditions, see the
":ref:`dev-manual/debugging:debugging parallel make races`"
section in the Yocto Project Development Tasks Manual.
:term:`PATCHRESOLVE`
Determines the action to take when a patch fails. You can set this
variable to one of two values: "noop" and "user".
The default value of "noop" causes the build to simply fail when the
OpenEmbedded build system cannot successfully apply a patch. Setting
the value to "user" causes the build system to launch a shell and
places you in the right location so that you can manually resolve the
conflicts.
Set this variable in your ``local.conf`` file.
:term:`PATCHTOOL`
Specifies the utility used to apply patches for a recipe during the
:ref:`ref-tasks-patch` task. You can specify one of
three utilities: "patch", "quilt", or "git". The default utility used
is "quilt" except for the quilt-native recipe itself. Because the
quilt tool is not available at the time quilt-native is being
patched, it uses "patch".
If you wish to use an alternative patching tool, set the variable in
the recipe using one of the following::
PATCHTOOL = "patch"
PATCHTOOL = "quilt"
PATCHTOOL = "git"
:term:`PE`
The epoch of the recipe. By default, this variable is unset. The
variable is used to make upgrades possible when the versioning scheme
changes in some backwards incompatible way.
:term:`PE` is the default value of the :term:`PKGE` variable.
:term:`PEP517_WHEEL_PATH`
When used by recipes that inherit the :ref:`ref-classes-python_pep517`
class, denotes the path to ``dist/`` (short for distribution) where the
binary archive ``wheel`` is built.
:term:`PERSISTENT_DIR`
See :term:`bitbake:PERSISTENT_DIR` in the BitBake manual.
:term:`PF`
Specifies the recipe or package name and includes all version and
revision numbers (i.e. ``glibc-2.13-r20+svnr15508/`` and
``bash-4.2-r1/``). This variable is comprised of the following:
${:term:`PN`}-${:term:`EXTENDPE`}${:term:`PV`}-${:term:`PR`}
:term:`PIXBUF_PACKAGES`
When inheriting the :ref:`ref-classes-pixbufcache`
class, this variable identifies packages that contain the pixbuf
loaders used with ``gdk-pixbuf``. By default, the
:ref:`ref-classes-pixbufcache` class assumes that
the loaders are in the recipe's main package (i.e.
``${``\ :term:`PN`\ ``}``). Use this variable if the
loaders you need are in a package other than that main package.
:term:`PKG`
The name of the resulting package created by the OpenEmbedded build
system.
.. note::
When using the :term:`PKG` variable, you must use a package name override.
For example, when the :ref:`ref-classes-debian` class renames the output
package, it does so by setting ``PKG:packagename``.
:term:`PKG_CONFIG_PATH`
The path to ``pkg-config`` files for the current build context.
``pkg-config`` reads this variable from the environment.
:term:`PKGD`
Points to the destination directory for files to be packaged before
they are split into individual packages. This directory defaults to
the following::
${WORKDIR}/package
Do not change this default.
:term:`PKGDATA_DIR`
Points to a shared, global-state directory that holds data generated
during the packaging process. During the packaging process, the
:ref:`ref-tasks-packagedata` task packages data
for each recipe and installs it into this temporary, shared area.
This directory defaults to the following, which you should not
change::
${STAGING_DIR_HOST}/pkgdata
For examples of how this data is used, see the
":ref:`overview-manual/concepts:automatically added runtime dependencies`"
section in the Yocto Project Overview and Concepts Manual and the
":ref:`dev-manual/debugging:viewing package information with \`\`oe-pkgdata-util\`\``"
section in the Yocto Project Development Tasks Manual. For more
information on the shared, global-state directory, see
:term:`STAGING_DIR_HOST`.
:term:`PKGDEST`
Points to the parent directory for files to be packaged after they
have been split into individual packages. This directory defaults to
the following::
${WORKDIR}/packages-split
Under this directory, the build system creates directories for each
package specified in :term:`PACKAGES`. Do not change
this default.
:term:`PKGDESTWORK`
Points to a temporary work area where the
:ref:`ref-tasks-package` task saves package metadata.
The :term:`PKGDESTWORK` location defaults to the following::
${WORKDIR}/pkgdata
Do not change this default.
The :ref:`ref-tasks-packagedata` task copies the
package metadata from :term:`PKGDESTWORK` to
:term:`PKGDATA_DIR` to make it available globally.
:term:`PKGE`
The epoch of the package(s) built by the recipe. By default, :term:`PKGE`
is set to :term:`PE`.
:term:`PKGR`
The revision of the package(s) built by the recipe. By default,
:term:`PKGR` is set to :term:`PR`.
:term:`PKGV`
The version of the package(s) built by the recipe. By default,
:term:`PKGV` is set to :term:`PV`.
:term:`PN`
This variable can have two separate functions depending on the
context: a recipe name or a resulting package name.
:term:`PN` refers to a recipe name in the context of a file used by the
OpenEmbedded build system as input to create a package. The name is
normally extracted from the recipe file name. For example, if the
recipe is named ``expat_2.0.1.bb``, then the default value of :term:`PN`
will be "expat".
The variable refers to a package name in the context of a file
created or produced by the OpenEmbedded build system.
If applicable, the :term:`PN` variable also contains any special suffix
or prefix. For example, using ``bash`` to build packages for the
native machine, :term:`PN` is ``bash-native``. Using ``bash`` to build
packages for the target and for Multilib, :term:`PN` would be ``bash``
and ``lib64-bash``, respectively.
:term:`POPULATE_SDK_POST_HOST_COMMAND`
Specifies a list of functions to call once the OpenEmbedded build
system has created the host part of the SDK. You can specify
functions separated by semicolons::
POPULATE_SDK_POST_HOST_COMMAND += "function; ... "
If you need to pass the SDK path to a command within a function, you
can use ``${SDK_DIR}``, which points to the parent directory used by
the OpenEmbedded build system when creating SDK output. See the
:term:`SDK_DIR` variable for more information.
:term:`POPULATE_SDK_POST_TARGET_COMMAND`
Specifies a list of functions to call once the OpenEmbedded build
system has created the target part of the SDK. You can specify
functions separated by semicolons::
POPULATE_SDK_POST_TARGET_COMMAND += "function; ... "
If you need to pass the SDK path to a command within a function, you
can use ``${SDK_DIR}``, which points to the parent directory used by
the OpenEmbedded build system when creating SDK output. See the
:term:`SDK_DIR` variable for more information.
:term:`PR`
The revision of the recipe. The default value for this variable is
"r0". Subsequent revisions of the recipe conventionally have the
values "r1", "r2", and so forth. When :term:`PV` increases,
:term:`PR` is conventionally reset to "r0".
.. note::
The OpenEmbedded build system does not need the aid of :term:`PR`
to know when to rebuild a recipe. The build system uses the task
:ref:`input checksums <overview-manual/concepts:checksums (signatures)>` along with the
:ref:`stamp <structure-build-tmp-stamps>` and
:ref:`overview-manual/concepts:shared state cache`
mechanisms.
The :term:`PR` variable primarily becomes significant when a package
manager dynamically installs packages on an already built image. In
this case, :term:`PR`, which is the default value of
:term:`PKGR`, helps the package manager distinguish which
package is the most recent one in cases where many packages have the
same :term:`PV` (i.e. :term:`PKGV`). A component having many packages with
the same :term:`PV` usually means that the packages all install the same
upstream version, but with later (:term:`PR`) version packages including
packaging fixes.
.. note::
:term:`PR` does not need to be increased for changes that do not change the
package contents or metadata.
Because manually managing :term:`PR` can be cumbersome and error-prone,
an automated solution exists. See the
":ref:`dev-manual/packages:working with a pr service`" section
in the Yocto Project Development Tasks Manual for more information.
:term:`PREFERRED_PROVIDER`
If multiple recipes provide the same item, this variable determines
which recipe is preferred and thus provides the item (i.e. the
preferred provider). You should always suffix this variable with the
name of the provided item. And, you should define the variable using
the preferred recipe's name (:term:`PN`). Here is a common
example::
PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto"
In the previous example, multiple recipes are providing "virtual/kernel".
The :term:`PREFERRED_PROVIDER` variable is set with the name (:term:`PN`) of
the recipe you prefer to provide "virtual/kernel".
Following are more examples::
PREFERRED_PROVIDER_virtual/xserver = "xserver-xf86"
PREFERRED_PROVIDER_virtual/libgl ?= "mesa"
For more
information, see the ":ref:`dev-manual/new-recipe:using virtual providers`"
section in the Yocto Project Development Tasks Manual.
.. note::
If you use a ``virtual/\*`` item with :term:`PREFERRED_PROVIDER`, then any
recipe that :term:`PROVIDES` that item but is not selected (defined)
by :term:`PREFERRED_PROVIDER` is prevented from building, which is usually
desirable since this mechanism is designed to select between mutually
exclusive alternative providers.
:term:`PREFERRED_PROVIDERS`
See :term:`bitbake:PREFERRED_PROVIDERS` in the BitBake manual.
:term:`PREFERRED_VERSION`
If there are multiple versions of a recipe available, this variable
determines which version should be given preference. You must always
suffix the variable with the :term:`PN` you want to select (`python` in
the first example below), and you should specify the :term:`PV`
accordingly (`3.4.0` in the example).
The :term:`PREFERRED_VERSION` variable supports limited wildcard use
through the "``%``" character. You can use the character to match any
number of characters, which can be useful when specifying versions
that contain long revision numbers that potentially change. Here are
two examples::
PREFERRED_VERSION_python = "3.4.0"
PREFERRED_VERSION_linux-yocto = "5.0%"
.. note::
The use of the "%" character is limited in that it only works at the end of the
string. You cannot use the wildcard character in any other
location of the string.
The specified version is matched against :term:`PV`, which
does not necessarily match the version part of the recipe's filename.
For example, consider two recipes ``foo_1.2.bb`` and ``foo_git.bb``
where ``foo_git.bb`` contains the following assignment::
PV = "1.1+git${SRCPV}"
In this case, the correct way to select
``foo_git.bb`` is by using an assignment such as the following::
PREFERRED_VERSION_foo = "1.1+git%"
Compare that previous example
against the following incorrect example, which does not work::
PREFERRED_VERSION_foo = "git"
Sometimes the :term:`PREFERRED_VERSION` variable can be set by
configuration files in a way that is hard to change. You can use
:term:`OVERRIDES` to set a machine-specific
override. Here is an example::
PREFERRED_VERSION_linux-yocto:qemux86 = "5.0%"
Although not recommended, worst case, you can also use the
"forcevariable" override, which is the strongest override possible.
Here is an example::
PREFERRED_VERSION_linux-yocto:forcevariable = "5.0%"
.. note::
The ``:forcevariable`` override is not handled specially. This override
only works because the default value of :term:`OVERRIDES` includes "forcevariable".
If a recipe with the specified version is not available, a warning
message will be shown. See :term:`REQUIRED_VERSION` if you want this
to be an error instead.
:term:`PREMIRRORS`
Specifies additional paths from which the OpenEmbedded build system
gets source code. When the build system searches for source code, it
first tries the local download directory. If that location fails, the
build system tries locations defined by :term:`PREMIRRORS`, the upstream
source, and then locations specified by
:term:`MIRRORS` in that order.
Assuming your distribution (:term:`DISTRO`) is "poky",
the default value for :term:`PREMIRRORS` is defined in the
``conf/distro/poky.conf`` file in the ``meta-poky`` Git repository.
Typically, you could add a specific server for the build system to
attempt before any others by adding something like the following to
the ``local.conf`` configuration file in the
:term:`Build Directory`::
PREMIRRORS:prepend = "\
git://.*/.* &YOCTO_DL_URL;/mirror/sources/ \
ftp://.*/.* &YOCTO_DL_URL;/mirror/sources/ \
http://.*/.* &YOCTO_DL_URL;/mirror/sources/ \
https://.*/.* &YOCTO_DL_URL;/mirror/sources/"
These changes cause the
build system to intercept Git, FTP, HTTP, and HTTPS requests and
direct them to the ``http://`` sources mirror. You can use
``file://`` URLs to point to local directories or network shares as
well.
:term:`PRIORITY`
Indicates the importance of a package.
:term:`PRIORITY` is considered to be part of the distribution policy
because the importance of any given recipe depends on the purpose for
which the distribution is being produced. Thus, :term:`PRIORITY` is not
normally set within recipes.
You can set :term:`PRIORITY` to "required", "standard", "extra", and
"optional", which is the default.
:term:`PRIVATE_LIBS`
Specifies libraries installed within a recipe that should be ignored
by the OpenEmbedded build system's shared library resolver. This
variable is typically used when software being built by a recipe has
its own private versions of a library normally provided by another
recipe. In this case, you would not want the package containing the
private libraries to be set as a dependency on other unrelated
packages that should instead depend on the package providing the
standard version of the library.
Libraries specified in this variable should be specified by their
file name. For example, from the Firefox recipe in meta-browser::
PRIVATE_LIBS = "libmozjs.so \
libxpcom.so \
libnspr4.so \
libxul.so \
libmozalloc.so \
libplc4.so \
libplds4.so"
For more information, see the
":ref:`overview-manual/concepts:automatically added runtime dependencies`"
section in the Yocto Project Overview and Concepts Manual.
:term:`PROVIDES`
A list of aliases by which a particular recipe can be known. By
default, a recipe's own :term:`PN` is implicitly already in its
:term:`PROVIDES` list and therefore does not need to mention that it
provides itself. If a recipe uses :term:`PROVIDES`, the additional
aliases are synonyms for the recipe and can be useful for satisfying
dependencies of other recipes during the build as specified by
:term:`DEPENDS`.
Consider the following example :term:`PROVIDES` statement from the recipe
file ``eudev_3.2.9.bb``::
PROVIDES += "udev"
The :term:`PROVIDES` statement
results in the "eudev" recipe also being available as simply "udev".
.. note::
A recipe's own recipe name (:term:`PN`) is always implicitly prepended
to :term:`PROVIDES`, so while using "+=" in the above example may not be
strictly necessary it is recommended to avoid confusion.
In addition to providing recipes under alternate names, the
:term:`PROVIDES` mechanism is also used to implement virtual targets. A
virtual target is a name that corresponds to some particular
functionality (e.g. a Linux kernel). Recipes that provide the
functionality in question list the virtual target in :term:`PROVIDES`.
Recipes that depend on the functionality in question can include the
virtual target in :term:`DEPENDS` to leave the choice of provider open.
Conventionally, virtual targets have names on the form
"virtual/function" (e.g. "virtual/kernel"). The slash is simply part
of the name and has no syntactical significance.
The :term:`PREFERRED_PROVIDER` variable is
used to select which particular recipe provides a virtual target.
.. note::
A corresponding mechanism for virtual runtime dependencies
(packages) exists. However, the mechanism does not depend on any
special functionality beyond ordinary variable assignments. For
example, ``VIRTUAL-RUNTIME_dev_manager`` refers to the package of
the component that manages the ``/dev`` directory.
Setting the "preferred provider" for runtime dependencies is as
simple as using the following assignment in a configuration file::
VIRTUAL-RUNTIME_dev_manager = "udev"
:term:`PRSERV_HOST`
The network based :term:`PR` service host and port.
The ``conf/templates/default/local.conf.sample.extended`` configuration
file in the :term:`Source Directory` shows how the :term:`PRSERV_HOST`
variable is set::
PRSERV_HOST = "localhost:0"
You must
set the variable if you want to automatically start a local :ref:`PR
service <dev-manual/packages:working with a pr service>`. You can
set :term:`PRSERV_HOST` to other values to use a remote PR service.
:term:`PSEUDO_IGNORE_PATHS`
A comma-separated (without spaces) list of path prefixes that should be ignored
by pseudo when monitoring and recording file operations, in order to avoid
problems with files being written to outside of the pseudo context and
reduce pseudo's overhead. A path is ignored if it matches any prefix in the list
and can include partial directory (or file) names.
:term:`PTEST_ENABLED`
Specifies whether or not :ref:`Package
Test <dev-manual/packages:testing packages with ptest>` (ptest)
functionality is enabled when building a recipe. You should not set
this variable directly. Enabling and disabling building Package Tests
at build time should be done by adding "ptest" to (or removing it
from) :term:`DISTRO_FEATURES`.
:term:`PV`
The version of the recipe. The version is normally extracted from the
recipe filename. For example, if the recipe is named
``expat_2.0.1.bb``, then the default value of :term:`PV` will be "2.0.1".
:term:`PV` is generally not overridden within a recipe unless it is
building an unstable (i.e. development) version from a source code
repository (e.g. Git or Subversion).
:term:`PV` is the default value of the :term:`PKGV` variable.
:term:`PYPI_PACKAGE`
When inheriting the :ref:`ref-classes-pypi` class, specifies the
`PyPI <https://pypi.org/>`__ package name to be built. The default value
is set based upon :term:`BPN` (stripping any "python-" or "python3-"
prefix off if present), however for some packages it will need to be set
explicitly if that will not match the package name (e.g. where the
package name has a prefix, underscores, uppercase letters etc.)
:term:`PYTHON_ABI`
When used by recipes that inherit the :ref:`ref-classes-setuptools3`
class, denotes the Application Binary Interface (ABI) currently in use
for Python. By default, the ABI is "m". You do not have to set this
variable as the OpenEmbedded build system sets it for you.
The OpenEmbedded build system uses the ABI to construct directory
names used when installing the Python headers and libraries in
sysroot (e.g. ``.../python3.3m/...``).
:term:`PYTHON_PN`
When used by recipes that inherit the :ref:`ref-classes-setuptools3`
class, specifies the major Python version being built. For Python 3.x,
:term:`PYTHON_PN` would be "python3". You do not have to set this
variable as the OpenEmbedded build system automatically sets it for you.
The variable allows recipes to use common infrastructure such as the
following::
DEPENDS += "${PYTHON_PN}-native"
In the previous example,
the version of the dependency is :term:`PYTHON_PN`.
:term:`QA_EMPTY_DIRS`
Specifies a list of directories that are expected to be empty when
packaging; if ``empty-dirs`` appears in :term:`ERROR_QA` or
:term:`WARN_QA` these will be checked and an error or warning
(respectively) will be produced.
The default :term:`QA_EMPTY_DIRS` value is set in
:ref:`insane.bbclass <ref-classes-insane>`.
:term:`QA_EMPTY_DIRS_RECOMMENDATION`
Specifies a recommendation for why a directory must be empty,
which will be included in the error message if a specific directory
is found to contain files. Must be overridden with the directory
path to match on.
If no recommendation is specified for a directory, then the default
"but it is expected to be empty" will be used.
An example message shows if files were present in '/dev'::
QA_EMPTY_DIRS_RECOMMENDATION:/dev = "but all devices must be created at runtime"
:term:`RANLIB`
The minimal command and arguments to run ``ranlib``.
:term:`RCONFLICTS`
The list of packages that conflict with packages. Note that packages
will not be installed if conflicting packages are not first removed.
Like all package-controlling variables, you must always use them in
conjunction with a package name override. Here is an example::
RCONFLICTS:${PN} = "another_conflicting_package_name"
BitBake, which the OpenEmbedded build system uses, supports
specifying versioned dependencies. Although the syntax varies
depending on the packaging format, BitBake hides these differences
from you. Here is the general syntax to specify versions with the
:term:`RCONFLICTS` variable::
RCONFLICTS:${PN} = "package (operator version)"
For ``operator``, you can specify the following:
- =
- <
- >
- <=
- >=
For example, the following sets up a dependency on version 1.2 or
greater of the package ``foo``::
RCONFLICTS:${PN} = "foo (>= 1.2)"
:term:`RDEPENDS`
Lists runtime dependencies of a package. These dependencies are other
packages that must be installed in order for the package to function
correctly. As an example, the following assignment declares that the
package ``foo`` needs the packages ``bar`` and ``baz`` to be
installed::
RDEPENDS:foo = "bar baz"
The most common types of package
runtime dependencies are automatically detected and added. Therefore,
most recipes do not need to set :term:`RDEPENDS`. For more information,
see the
":ref:`overview-manual/concepts:automatically added runtime dependencies`"
section in the Yocto Project Overview and Concepts Manual.
The practical effect of the above :term:`RDEPENDS` assignment is that
``bar`` and ``baz`` will be declared as dependencies inside the
package ``foo`` when it is written out by one of the
:ref:`do_package_write_* <ref-tasks-package_write_deb>` tasks.
Exactly how this is done depends on which package format is used,
which is determined by
:term:`PACKAGE_CLASSES`. When the
corresponding package manager installs the package, it will know to
also install the packages on which it depends.
To ensure that the packages ``bar`` and ``baz`` get built, the
previous :term:`RDEPENDS` assignment also causes a task dependency to be
added. This dependency is from the recipe's
:ref:`ref-tasks-build` (not to be confused with
:ref:`ref-tasks-compile`) task to the
:ref:`do_package_write_* <ref-tasks-package_write_deb>` task of the recipes that build ``bar`` and
``baz``.
The names of the packages you list within :term:`RDEPENDS` must be the
names of other packages --- they cannot be recipe names. Although
package names and recipe names usually match, the important point
here is that you are providing package names within the :term:`RDEPENDS`
variable. For an example of the default list of packages created from
a recipe, see the :term:`PACKAGES` variable.
Because the :term:`RDEPENDS` variable applies to packages being built,
you should always use the variable in a form with an attached package
name (remember that a single recipe can build multiple packages). For
example, suppose you are building a development package that depends
on the ``perl`` package. In this case, you would use the following
:term:`RDEPENDS` statement::
RDEPENDS:${PN}-dev += "perl"
In the example,
the development package depends on the ``perl`` package. Thus, the
:term:`RDEPENDS` variable has the ``${PN}-dev`` package name as part of
the variable.
.. note::
``RDEPENDS:${PN}-dev`` includes ``${``\ :term:`PN`\ ``}``
by default. This default is set in the BitBake configuration file
(``meta/conf/bitbake.conf``). Be careful not to accidentally remove
``${PN}`` when modifying ``RDEPENDS:${PN}-dev``. Use the "+=" operator
rather than the "=" operator.
The package names you use with :term:`RDEPENDS` must appear as they would
in the :term:`PACKAGES` variable. The :term:`PKG` variable
allows a different name to be used for the final package (e.g. the
:ref:`ref-classes-debian` class uses this to rename
packages), but this final package name cannot be used with
:term:`RDEPENDS`, which makes sense as :term:`RDEPENDS` is meant to be
independent of the package format used.
BitBake, which the OpenEmbedded build system uses, supports
specifying versioned dependencies. Although the syntax varies
depending on the packaging format, BitBake hides these differences
from you. Here is the general syntax to specify versions with the
:term:`RDEPENDS` variable::
RDEPENDS:${PN} = "package (operator version)"
For ``operator``, you can specify the following:
- =
- <
- >
- <=
- >=
For version, provide the version number.
.. note::
You can use :term:`EXTENDPKGV` to provide a full package version
specification.
For example, the following sets up a dependency on version 1.2 or
greater of the package ``foo``::
RDEPENDS:${PN} = "foo (>= 1.2)"
For information on build-time dependencies, see the
:term:`DEPENDS` variable. You can also see the
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:tasks`" and
":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-execution:dependencies`" sections in the
BitBake User Manual for additional information on tasks and
dependencies.
:term:`RECIPE_NO_UPDATE_REASON`
If a recipe should not be replaced by a more recent upstream version,
putting the reason why in this variable in a recipe allows
``devtool check-upgrade-status`` command to display it, as explained
in the ":ref:`ref-manual/devtool-reference:checking on the upgrade status of a recipe`"
section.
:term:`REPODIR`
See :term:`bitbake:REPODIR` in the BitBake manual.
:term:`REQUIRED_DISTRO_FEATURES`
When inheriting the :ref:`ref-classes-features_check`
class, this variable identifies distribution features that must exist
in the current configuration in order for the OpenEmbedded build
system to build the recipe. In other words, if the
:term:`REQUIRED_DISTRO_FEATURES` variable lists a feature that does not
appear in :term:`DISTRO_FEATURES` within the current configuration, then
the recipe will be skipped, and if the build system attempts to build
the recipe then an error will be triggered.
:term:`REQUIRED_VERSION`
If there are multiple versions of a recipe available, this variable
determines which version should be given preference.
:term:`REQUIRED_VERSION` works in exactly the same manner as
:term:`PREFERRED_VERSION`, except that if the specified version is not
available then an error message is shown and the build fails
immediately.
If both :term:`REQUIRED_VERSION` and :term:`PREFERRED_VERSION` are set
for the same recipe, the :term:`REQUIRED_VERSION` value applies.
:term:`RM_WORK_EXCLUDE`
With :ref:`ref-classes-rm-work` enabled, this variable
specifies a list of recipes whose work directories should not be removed.
See the ":ref:`ref-classes-rm-work`" section for more details.
:term:`ROOT_HOME`
Defines the root home directory. By default, this directory is set as
follows in the BitBake configuration file::
ROOT_HOME ??= "/home/root"
.. note::
This default value is likely used because some embedded solutions
prefer to have a read-only root filesystem and prefer to keep
writeable data in one place.
You can override the default by setting the variable in any layer or
in the ``local.conf`` file. Because the default is set using a "weak"
assignment (i.e. "??="), you can use either of the following forms to
define your override::
ROOT_HOME = "/root"
ROOT_HOME ?= "/root"
These
override examples use ``/root``, which is probably the most commonly
used override.
:term:`ROOTFS`
Indicates a filesystem image to include as the root filesystem.
The :term:`ROOTFS` variable is an optional variable used with the
:ref:`ref-classes-image-live` class.
:term:`ROOTFS_POSTINSTALL_COMMAND`
Specifies a list of functions to call after the OpenEmbedded build
system has installed packages. You can specify functions separated by
semicolons::
ROOTFS_POSTINSTALL_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within a
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`ROOTFS_POSTPROCESS_COMMAND`
Specifies a list of functions to call once the OpenEmbedded build
system has created the root filesystem. You can specify functions
separated by semicolons::
ROOTFS_POSTPROCESS_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within a
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`ROOTFS_POSTUNINSTALL_COMMAND`
Specifies a list of functions to call after the OpenEmbedded build
system has removed unnecessary packages. When runtime package
management is disabled in the image, several packages are removed
including ``base-passwd``, ``shadow``, and ``update-alternatives``.
You can specify functions separated by semicolons::
ROOTFS_POSTUNINSTALL_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within a
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`ROOTFS_PREPROCESS_COMMAND`
Specifies a list of functions to call before the OpenEmbedded build
system has created the root filesystem. You can specify functions
separated by semicolons::
ROOTFS_PREPROCESS_COMMAND += "function; ... "
If you need to pass the root filesystem path to a command within a
function, you can use ``${IMAGE_ROOTFS}``, which points to the
directory that becomes the root filesystem image. See the
:term:`IMAGE_ROOTFS` variable for more
information.
:term:`RPROVIDES`
A list of package name aliases that a package also provides. These
aliases are useful for satisfying runtime dependencies of other
packages both during the build and on the target (as specified by
:term:`RDEPENDS`).
.. note::
A package's own name is implicitly already in its :term:`RPROVIDES` list.
As with all package-controlling variables, you must always use the
variable in conjunction with a package name override. Here is an
example::
RPROVIDES:${PN} = "widget-abi-2"
:term:`RRECOMMENDS`
A list of packages that extends the usability of a package being
built. The package being built does not depend on this list of
packages in order to successfully build, but rather uses them for
extended usability. To specify runtime dependencies for packages, see
the :term:`RDEPENDS` variable.
The package manager will automatically install the :term:`RRECOMMENDS`
list of packages when installing the built package. However, you can
prevent listed packages from being installed by using the
:term:`BAD_RECOMMENDATIONS`,
:term:`NO_RECOMMENDATIONS`, and
:term:`PACKAGE_EXCLUDE` variables.
Packages specified in :term:`RRECOMMENDS` need not actually be produced.
However, there must be a recipe providing each package, either
through the :term:`PACKAGES` or
:term:`PACKAGES_DYNAMIC` variables or the
:term:`RPROVIDES` variable, or an error will occur
during the build. If such a recipe does exist and the package is not
produced, the build continues without error.
Because the :term:`RRECOMMENDS` variable applies to packages being built,
you should always attach an override to the variable to specify the
particular package whose usability is being extended. For example,
suppose you are building a development package that is extended to
support wireless functionality. In this case, you would use the
following::
RRECOMMENDS:${PN}-dev += "wireless_package_name"
In the
example, the package name (``${PN}-dev``) must appear as it would in
the :term:`PACKAGES` namespace before any renaming of the output package
by classes such as :ref:`ref-classes-debian`.
BitBake, which the OpenEmbedded build system uses, supports
specifying versioned recommends. Although the syntax varies depending
on the packaging format, BitBake hides these differences from you.
Here is the general syntax to specify versions with the
:term:`RRECOMMENDS` variable::
RRECOMMENDS:${PN} = "package (operator version)"
For ``operator``, you can specify the following:
- =
- <
- >
- <=
- >=
For example, the following sets up a recommend on version 1.2 or
greater of the package ``foo``::
RRECOMMENDS:${PN} = "foo (>= 1.2)"
:term:`RREPLACES`
A list of packages replaced by a package. The package manager uses
this variable to determine which package should be installed to
replace other package(s) during an upgrade. In order to also have the
other package(s) removed at the same time, you must add the name of
the other package to the :term:`RCONFLICTS` variable.
As with all package-controlling variables, you must use this variable
in conjunction with a package name override. Here is an example::
RREPLACES:${PN} = "other_package_being_replaced"
BitBake, which the OpenEmbedded build system uses, supports
specifying versioned replacements. Although the syntax varies
depending on the packaging format, BitBake hides these differences
from you. Here is the general syntax to specify versions with the
:term:`RREPLACES` variable::
RREPLACES:${PN} = "package (operator version)"
For ``operator``, you can specify the following:
- =
- <
- >
- <=
- >=
For example, the following sets up a replacement using version 1.2
or greater of the package ``foo``::
RREPLACES:${PN} = "foo (>= 1.2)"
:term:`RSUGGESTS`
A list of additional packages that you can suggest for installation
by the package manager at the time a package is installed. Not all
package managers support this functionality.
As with all package-controlling variables, you must always use this
variable in conjunction with a package name override. Here is an
example::
RSUGGESTS:${PN} = "useful_package another_package"
:term:`S`
The location in the :term:`Build Directory` where
unpacked recipe source code resides. By default, this directory is
``${``\ :term:`WORKDIR`\ ``}/${``\ :term:`BPN`\ ``}-${``\ :term:`PV`\ ``}``,
where ``${BPN}`` is the base recipe name and ``${PV}`` is the recipe
version. If the source tarball extracts the code to a directory named
anything other than ``${BPN}-${PV}``, or if the source code is
fetched from an SCM such as Git or Subversion, then you must set
:term:`S` in the recipe so that the OpenEmbedded build system knows where
to find the unpacked source.
As an example, assume a :term:`Source Directory`
top-level folder named ``poky`` and a default :term:`Build Directory` at
``poky/build``. In this case, the work directory the build system
uses to keep the unpacked recipe for ``db`` is the following::
poky/build/tmp/work/qemux86-poky-linux/db/5.1.19-r3/db-5.1.19
The unpacked source code resides in the ``db-5.1.19`` folder.
This next example assumes a Git repository. By default, Git
repositories are cloned to ``${WORKDIR}/git`` during
:ref:`ref-tasks-fetch`. Since this path is different
from the default value of :term:`S`, you must set it specifically so the
source can be located::
SRC_URI = "git://path/to/repo.git;branch=main"
S = "${WORKDIR}/git"
:term:`SANITY_REQUIRED_UTILITIES`
Specifies a list of command-line utilities that should be checked for
during the initial sanity checking process when running BitBake. If
any of the utilities are not installed on the build host, then
BitBake immediately exits with an error.
:term:`SANITY_TESTED_DISTROS`
A list of the host distribution identifiers that the build system has
been tested against. Identifiers consist of the host distributor ID
followed by the release, as reported by the ``lsb_release`` tool or
as read from ``/etc/lsb-release``. Separate the list items with
explicit newline characters (``\n``). If :term:`SANITY_TESTED_DISTROS` is
not empty and the current value of
:term:`NATIVELSBSTRING` does not appear in the
list, then the build system reports a warning that indicates the
current host distribution has not been tested as a build host.
:term:`SDK_ARCH`
The target architecture for the SDK. Typically, you do not directly
set this variable. Instead, use :term:`SDKMACHINE`.
:term:`SDK_BUILDINFO_FILE`
When using the :ref:`ref-classes-image-buildinfo` class,
specifies the file in the SDK to write the build information into. The
default value is "``/buildinfo``".
:term:`SDK_CUSTOM_TEMPLATECONF`
When building the extensible SDK, if :term:`SDK_CUSTOM_TEMPLATECONF` is set to
"1" and a ``conf/templateconf.cfg`` file exists in the :term:`Build Directory`
(:term:`TOPDIR`) then this will be copied into the SDK.
:term:`SDK_DEPLOY`
The directory set up and used by the
:ref:`populate_sdk_base <ref-classes-populate-sdk>` class to which the
SDK is deployed. The :ref:`populate_sdk_base <ref-classes-populate-sdk>`
class defines :term:`SDK_DEPLOY` as follows::
SDK_DEPLOY = "${TMPDIR}/deploy/sdk"
:term:`SDK_DIR`
The parent directory used by the OpenEmbedded build system when
creating SDK output. The
:ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class defines
the variable as follows::
SDK_DIR = "${WORKDIR}/sdk"
.. note::
The :term:`SDK_DIR` directory is a temporary directory as it is part of
:term:`WORKDIR`. The final output directory is :term:`SDK_DEPLOY`.
:term:`SDK_EXT_TYPE`
Controls whether or not shared state artifacts are copied into the
extensible SDK. The default value of "full" copies all of the
required shared state artifacts into the extensible SDK. The value
"minimal" leaves these artifacts out of the SDK.
.. note::
If you set the variable to "minimal", you need to ensure
:term:`SSTATE_MIRRORS` is set in the SDK's configuration to enable the
artifacts to be fetched as needed.
:term:`SDK_HOST_MANIFEST`
The manifest file for the host part of the SDK. This file lists all
the installed packages that make up the host part of the SDK. The
file contains package information on a line-per-package basis as
follows::
packagename packagearch version
The :ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class
defines the manifest file as follows::
SDK_HOST_MANIFEST = "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.host.manifest"
The location is derived using the :term:`SDK_DEPLOY` and
:term:`TOOLCHAIN_OUTPUTNAME` variables.
:term:`SDK_INCLUDE_PKGDATA`
When set to "1", specifies to include the packagedata for all recipes
in the "world" target in the extensible SDK. Including this data
allows the ``devtool search`` command to find these recipes in search
results, as well as allows the ``devtool add`` command to map
dependencies more effectively.
.. note::
Enabling the :term:`SDK_INCLUDE_PKGDATA`
variable significantly increases build time because all of world
needs to be built. Enabling the variable also slightly increases
the size of the extensible SDK.
:term:`SDK_INCLUDE_TOOLCHAIN`
When set to "1", specifies to include the toolchain in the extensible
SDK. Including the toolchain is useful particularly when
:term:`SDK_EXT_TYPE` is set to "minimal" to keep
the SDK reasonably small but you still want to provide a usable
toolchain. For example, suppose you want to use the toolchain from an
IDE or from other tools and you do not want to perform additional
steps to install the toolchain.
The :term:`SDK_INCLUDE_TOOLCHAIN` variable defaults to "0" if
:term:`SDK_EXT_TYPE` is set to "minimal", and defaults to "1" if
:term:`SDK_EXT_TYPE` is set to "full".
:term:`SDK_NAME`
The base name for SDK output files. The name is derived from the
:term:`DISTRO`, :term:`TCLIBC`,
:term:`SDK_ARCH`,
:term:`IMAGE_BASENAME`, and
:term:`TUNE_PKGARCH` variables::
SDK_NAME = "${DISTRO}-${TCLIBC}-${SDK_ARCH}-${IMAGE_BASENAME}-${TUNE_PKGARCH}"
:term:`SDK_OS`
Specifies the operating system for which the SDK will be built. The
default value is the value of :term:`BUILD_OS`.
:term:`SDK_OUTPUT`
The location used by the OpenEmbedded build system when creating SDK
output. The :ref:`populate_sdk_base <ref-classes-populate-sdk-*>`
class defines the variable as follows::
SDK_DIR = "${WORKDIR}/sdk"
SDK_OUTPUT = "${SDK_DIR}/image"
SDK_DEPLOY = "${DEPLOY_DIR}/sdk"
.. note::
The :term:`SDK_OUTPUT` directory is a temporary directory as it is part of
:term:`WORKDIR` by way of :term:`SDK_DIR`. The final output directory is
:term:`SDK_DEPLOY`.
:term:`SDK_PACKAGE_ARCHS`
Specifies a list of architectures compatible with the SDK machine.
This variable is set automatically and should not normally be
hand-edited. Entries are separated using spaces and listed in order
of priority. The default value for :term:`SDK_PACKAGE_ARCHS` is "all any
noarch ${SDK_ARCH}-${SDKPKGSUFFIX}".
:term:`SDK_POSTPROCESS_COMMAND`
Specifies a list of functions to call once the OpenEmbedded build
system creates the SDK. You can specify functions separated by
semicolons: SDK_POSTPROCESS_COMMAND += "function; ... "
If you need to pass an SDK path to a command within a function, you
can use ``${SDK_DIR}``, which points to the parent directory used by
the OpenEmbedded build system when creating SDK output. See the
:term:`SDK_DIR` variable for more information.
:term:`SDK_PREFIX`
The toolchain binary prefix used for
:ref:`ref-classes-nativesdk` recipes. The
OpenEmbedded build system uses the :term:`SDK_PREFIX` value to set the
:term:`TARGET_PREFIX` when building
``nativesdk`` recipes. The default value is "${SDK_SYS}-".
:term:`SDK_RECRDEP_TASKS`
A list of shared state tasks added to the extensible SDK. By default,
the following tasks are added:
- :ref:`ref-tasks-populate_lic`
- :ref:`ref-tasks-package_qa`
- :ref:`ref-tasks-populate_sysroot`
- :ref:`ref-tasks-deploy`
Despite the default value of "" for the
:term:`SDK_RECRDEP_TASKS` variable, the above four tasks are always added
to the SDK. To specify tasks beyond these four, you need to use the
:term:`SDK_RECRDEP_TASKS` variable (e.g. you are defining additional
tasks that are needed in order to build
:term:`SDK_TARGETS`).
:term:`SDK_SYS`
Specifies the system, including the architecture and the operating
system, for which the SDK will be built.
The OpenEmbedded build system automatically sets this variable based
on :term:`SDK_ARCH`,
:term:`SDK_VENDOR`, and
:term:`SDK_OS`. You do not need to set the :term:`SDK_SYS`
variable yourself.
:term:`SDK_TARGET_MANIFEST`
The manifest file for the target part of the SDK. This file lists all
the installed packages that make up the target part of the SDK. The
file contains package information on a line-per-package basis as
follows::
packagename packagearch version
The :ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class
defines the manifest file as follows::
SDK_TARGET_MANIFEST = "${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.target.manifest"
The location is derived using the :term:`SDK_DEPLOY` and
:term:`TOOLCHAIN_OUTPUTNAME` variables.
:term:`SDK_TARGETS`
A list of targets to install from shared state as part of the
standard or extensible SDK installation. The default value is "${PN}"
(i.e. the image from which the SDK is built).
The :term:`SDK_TARGETS` variable is an internal variable and typically
would not be changed.
:term:`SDK_TITLE`
The title to be printed when running the SDK installer. By default,
this title is based on the :term:`DISTRO_NAME` or
:term:`DISTRO` variable and is set in the
:ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class as
follows::
SDK_TITLE ??= "${@d.getVar('DISTRO_NAME') or d.getVar('DISTRO')} SDK"
For the default distribution "poky",
:term:`SDK_TITLE` is set to "Poky (Yocto Project Reference Distro)".
For information on how to change this default title, see the
":ref:`sdk-manual/appendix-customizing:changing the extensible sdk installer title`"
section in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual.
:term:`SDK_TOOLCHAIN_LANGS`
Specifies programming languages to support in the SDK, as a
space-separated list. Currently supported items are ``rust`` and ``go``.
:term:`SDK_UPDATE_URL`
An optional URL for an update server for the extensible SDK. If set,
the value is used as the default update server when running
``devtool sdk-update`` within the extensible SDK.
:term:`SDK_VENDOR`
Specifies the name of the SDK vendor.
:term:`SDK_VERSION`
Specifies the version of the SDK. The Poky distribution configuration file
(``/meta-poky/conf/distro/poky.conf``) sets the default
:term:`SDK_VERSION` as follows::
SDK_VERSION = "${@d.getVar('DISTRO_VERSION').replace('snapshot-${METADATA_REVISION}', 'snapshot')}"
For additional information, see the
:term:`DISTRO_VERSION` and
:term:`METADATA_REVISION` variables.
:term:`SDKEXTPATH`
The default installation directory for the Extensible SDK. By
default, this directory is based on the :term:`DISTRO`
variable and is set in the
:ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class as
follows::
SDKEXTPATH ??= "~/${@d.getVar('DISTRO')}_sdk"
For the
default distribution "poky", the :term:`SDKEXTPATH` is set to "poky_sdk".
For information on how to change this default directory, see the
":ref:`sdk-manual/appendix-customizing:changing the default sdk installation directory`"
section in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual.
:term:`SDKIMAGE_FEATURES`
Equivalent to :term:`IMAGE_FEATURES`. However, this variable applies to
the SDK generated from an image using the following command::
$ bitbake -c populate_sdk imagename
:term:`SDKMACHINE`
The machine for which the SDK is built. In other words, the SDK is built
such that it runs on the target you specify with the :term:`SDKMACHINE`
value. The value points to a corresponding ``.conf`` file under
``conf/machine-sdk/`` in the enabled layers, for example ``aarch64``,
``i586``, ``i686``, ``ppc64``, ``ppc64le``, and ``x86_64`` are
:oe_git:`available in OpenEmbedded-Core </openembedded-core/tree/meta/conf/machine-sdk>`.
The variable defaults to :term:`BUILD_ARCH` so that SDKs are built for the
architecture of the build machine.
.. note::
You cannot set the :term:`SDKMACHINE`
variable in your distribution configuration file. If you do, the
configuration will not take effect.
:term:`SDKPATH`
Defines the path offered to the user for installation of the SDK that
is generated by the OpenEmbedded build system. The path appears as
the default location for installing the SDK when you run the SDK's
installation script. You can override the offered path when you run
the script.
:term:`SDKTARGETSYSROOT`
The full path to the sysroot used for cross-compilation within an SDK
as it will be when installed into the default
:term:`SDKPATH`.
:term:`SECTION`
The section in which packages should be categorized. Package
management utilities can make use of this variable.
:term:`SELECTED_OPTIMIZATION`
Specifies the optimization flags passed to the C compiler when
building for the target. The flags are passed through the default
value of the :term:`TARGET_CFLAGS` variable.
The :term:`SELECTED_OPTIMIZATION` variable takes the value of
:term:`FULL_OPTIMIZATION` unless :term:`DEBUG_BUILD` = "1", in which
case the value of :term:`DEBUG_OPTIMIZATION` is used.
:term:`SERIAL_CONSOLES`
Defines a serial console (TTY) to enable using
`getty <https://en.wikipedia.org/wiki/Getty_(Unix)>`__. Provide a
value that specifies the baud rate followed by the TTY device name
separated by a semicolon. Use spaces to separate multiple devices::
SERIAL_CONSOLES = "115200;ttyS0 115200;ttyS1"
:term:`SERIAL_CONSOLES_CHECK`
Specifies serial consoles, which must be listed in
:term:`SERIAL_CONSOLES`, to check against
``/proc/console`` before enabling them using getty. This variable
allows aliasing in the format: <device>:<alias>. If a device was
listed as "sclp_line0" in ``/dev/`` and "ttyS0" was listed in
``/proc/console``, you would do the following::
SERIAL_CONSOLES_CHECK = "slcp_line0:ttyS0"
This variable is currently only supported with SysVinit (i.e. not
with systemd). Note that :term:`SERIAL_CONSOLES_CHECK` also requires
``/etc/inittab`` to be writable when used with SysVinit. This makes it
incompatible with customizations such as the following::
EXTRA_IMAGE_FEATURES += "read-only-rootfs"
:term:`SETUPTOOLS_BUILD_ARGS`
When used by recipes that inherit the :ref:`ref-classes-setuptools3`
class, this variable can be used to specify additional arguments to be
passed to ``setup.py build`` in the ``setuptools3_do_compile()`` task.
:term:`SETUPTOOLS_INSTALL_ARGS`
When used by recipes that inherit the :ref:`ref-classes-setuptools3`
class, this variable can be used to specify additional arguments to be
passed to ``setup.py install`` in the ``setuptools3_do_install()`` task.
:term:`SETUPTOOLS_SETUP_PATH`
When used by recipes that inherit the :ref:`ref-classes-setuptools3`
class, this variable should be used to specify the directory in which
the ``setup.py`` file is located if it is not at the root of the source
tree (as specified by :term:`S`). For example, in a recipe where the
sources are fetched from a Git repository and ``setup.py`` is in a
``python/pythonmodule`` subdirectory, you would have this::
S = "${WORKDIR}/git"
SETUPTOOLS_SETUP_PATH = "${S}/python/pythonmodule"
:term:`SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS`
A list of recipe dependencies that should not be used to determine
signatures of tasks from one recipe when they depend on tasks from
another recipe. For example::
SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS += "intone->mplayer2"
In the previous example, ``intone`` depends on ``mplayer2``.
You can use the special token ``"*"`` on the left-hand side of the
dependency to match all recipes except the one on the right-hand
side. Here is an example::
SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS += "*->quilt-native"
In the previous example, all recipes except ``quilt-native`` ignore
task signatures from the ``quilt-native`` recipe when determining
their task signatures.
Use of this variable is one mechanism to remove dependencies that
affect task signatures and thus force rebuilds when a recipe changes.
.. note::
If you add an inappropriate dependency for a recipe relationship,
the software might break during runtime if the interface of the
second recipe was changed after the first recipe had been built.
:term:`SIGGEN_EXCLUDERECIPES_ABISAFE`
A list of recipes that are completely stable and will never change.
The ABI for the recipes in the list are presented by output from the
tasks run to build the recipe. Use of this variable is one way to
remove dependencies from one recipe on another that affect task
signatures and thus force rebuilds when the recipe changes.
.. note::
If you add an inappropriate variable to this list, the software
might break at runtime if the interface of the recipe was changed
after the other had been built.
:term:`SITEINFO_BITS`
Specifies the number of bits for the target system CPU. The value
should be either "32" or "64".
:term:`SITEINFO_ENDIANNESS`
Specifies the endian byte order of the target system. The value
should be either "le" for little-endian or "be" for big-endian.
:term:`SKIP_FILEDEPS`
Enables removal of all files from the "Provides" section of an RPM
package. Removal of these files is required for packages containing
prebuilt binaries and libraries such as ``libstdc++`` and ``glibc``.
To enable file removal, set the variable to "1" in your
``conf/local.conf`` configuration file in your:
:term:`Build Directory`::
SKIP_FILEDEPS = "1"
:term:`SKIP_RECIPE`
Used to prevent the OpenEmbedded build system from building a given
recipe. Specify the :term:`PN` value as a variable flag (``varflag``)
and provide a reason, which will be reported when attempting to
build the recipe.
To prevent a recipe from being built, use the :term:`SKIP_RECIPE`
variable in your ``local.conf`` file or distribution configuration.
Here is an example which prevents ``myrecipe`` from being built::
SKIP_RECIPE[myrecipe] = "Not supported by our organization."
:term:`SOC_FAMILY`
Groups together machines based upon the same family of SOC (System On
Chip). You typically set this variable in a common ``.inc`` file that
you include in the configuration files of all the machines.
.. note::
You must include ``conf/machine/include/soc-family.inc`` for this
variable to appear in :term:`MACHINEOVERRIDES`.
:term:`SOLIBS`
Defines the suffix for shared libraries used on the target platform.
By default, this suffix is ".so.*" for all Linux-based systems and is
defined in the ``meta/conf/bitbake.conf`` configuration file.
You will see this variable referenced in the default values of
``FILES:${PN}``.
:term:`SOLIBSDEV`
Defines the suffix for the development symbolic link (symlink) for
shared libraries on the target platform. By default, this suffix is
".so" for Linux-based systems and is defined in the
``meta/conf/bitbake.conf`` configuration file.
You will see this variable referenced in the default values of
``FILES:${PN}-dev``.
:term:`SOURCE_DATE_EPOCH`
This defines a date expressed in number of seconds since
the UNIX EPOCH (01 Jan 1970 00:00:00 UTC), which is used by
multiple build systems to force a timestamp in built binaries.
Many upstream projects already support this variable.
You will find more details in the `official specifications
<https://reproducible-builds.org/specs/source-date-epoch/>`__.
A value for each recipe is computed from the sources by
:oe_git:`meta/lib/oe/reproducible.py </openembedded-core/tree/meta/lib/oe/reproducible.py>`.
If a recipe wishes to override the default behavior, it should set its
own :term:`SOURCE_DATE_EPOCH` value::
SOURCE_DATE_EPOCH = "1613559011"
:term:`SOURCE_MIRROR_FETCH`
When you are fetching files to create a mirror of sources (i.e.
creating a source mirror), setting :term:`SOURCE_MIRROR_FETCH` to "1" in
your ``local.conf`` configuration file ensures the source for all
recipes are fetched regardless of whether or not a recipe is
compatible with the configuration. A recipe is considered
incompatible with the currently configured machine when either or
both the :term:`COMPATIBLE_MACHINE`
variable and :term:`COMPATIBLE_HOST` variables
specify compatibility with a machine other than that of the current
machine or host.
.. note::
Do not set the :term:`SOURCE_MIRROR_FETCH`
variable unless you are creating a source mirror. In other words,
do not set the variable during a normal build.
:term:`SOURCE_MIRROR_URL`
Defines your own :term:`PREMIRRORS` from which to
first fetch source before attempting to fetch from the upstream
specified in :term:`SRC_URI`.
To use this variable, you must globally inherit the
:ref:`ref-classes-own-mirrors` class and then provide
the URL to your mirrors. Here is the general syntax::
INHERIT += "own-mirrors"
SOURCE_MIRROR_URL = "http://example.com/my_source_mirror"
.. note::
You can specify only a single URL in :term:`SOURCE_MIRROR_URL`.
:term:`SPDX_ARCHIVE_PACKAGED`
This option allows to add to :term:`SPDX` output compressed archives
of the files in the generated target packages.
Such archives are available in
``tmp/deploy/spdx/MACHINE/packages/packagename.tar.zst``
under the :term:`Build Directory`.
Enable this option as follows::
SPDX_ARCHIVE_PACKAGED = "1"
According to our tests on release 4.1 "langdale", building
``core-image-minimal`` for the ``qemux86-64`` machine, enabling this
option multiplied the size of the ``tmp/deploy/spdx`` directory by a
factor of 13 (+1.6 GiB for this image), compared to just using the
:ref:`ref-classes-create-spdx` class with no option.
Note that this option doesn't increase the size of :term:`SPDX`
files in ``tmp/deploy/images/MACHINE``.
:term:`SPDX_ARCHIVE_SOURCES`
This option allows to add to :term:`SPDX` output compressed archives
of the sources for packages installed on the target. It currently
only works when :term:`SPDX_INCLUDE_SOURCES` is set.
This is one way of fulfilling "source code access" license
requirements.
Such source archives are available in
``tmp/deploy/spdx/MACHINE/recipes/recipe-packagename.tar.zst``
under the :term:`Build Directory`.
Enable this option as follows::
SPDX_INCLUDE_SOURCES = "1"
SPDX_ARCHIVE_SOURCES = "1"
According to our tests on release 4.1 "langdale", building
``core-image-minimal`` for the ``qemux86-64`` machine, enabling
these options multiplied the size of the ``tmp/deploy/spdx``
directory by a factor of 11 (+1.4 GiB for this image),
compared to just using the :ref:`ref-classes-create-spdx`
class with no option.
Note that using this option only marginally increases the size
of the :term:`SPDX` output in ``tmp/deploy/images/MACHINE/``
(+ 0.07\% with the tested image), compared to just enabling
:term:`SPDX_INCLUDE_SOURCES`.
:term:`SPDX_INCLUDE_SOURCES`
This option allows to add a description of the source files used to build
the host tools and the target packages, to the ``spdx.json`` files in
``tmp/deploy/spdx/MACHINE/recipes/`` under the :term:`Build Directory`.
As a consequence, the ``spdx.json`` files under the ``by-namespace`` and
``packages`` subdirectories in ``tmp/deploy/spdx/MACHINE`` are also
modified to include references to such source file descriptions.
Enable this option as follows::
SPDX_INCLUDE_SOURCES = "1"
According to our tests on release 4.1 "langdale", building
``core-image-minimal`` for the ``qemux86-64`` machine, enabling
this option multiplied the total size of the ``tmp/deploy/spdx``
directory by a factor of 3 (+291 MiB for this image),
and the size of the ``IMAGE-MACHINE.spdx.tar.zst`` in
``tmp/deploy/images/MACHINE`` by a factor of 130 (+15 MiB for this
image), compared to just using the :ref:`ref-classes-create-spdx` class
with no option.
:term:`SPDX_PRETTY`
This option makes the SPDX output more human-readable, using
identation and newlines, instead of the default output in a
single line::
SPDX_PRETTY = "1"
The generated SPDX files are approximately 20% bigger, but
this option is recommended if you want to inspect the SPDX
output files with a text editor.
:term:`SPDXLICENSEMAP`
Maps commonly used license names to their SPDX counterparts found in
``meta/files/common-licenses/``. For the default :term:`SPDXLICENSEMAP`
mappings, see the ``meta/conf/licenses.conf`` file.
For additional information, see the :term:`LICENSE`
variable.
:term:`SPECIAL_PKGSUFFIX`
A list of prefixes for :term:`PN` used by the OpenEmbedded
build system to create variants of recipes or packages. The list
specifies the prefixes to strip off during certain circumstances such
as the generation of the :term:`BPN` variable.
:term:`SPL_BINARY`
The file type for the Secondary Program Loader (SPL). Some devices
use an SPL from which to boot (e.g. the BeagleBone development
board). For such cases, you can declare the file type of the SPL
binary in the ``u-boot.inc`` include file, which is used in the
U-Boot recipe.
The SPL file type is set to "null" by default in the ``u-boot.inc``
file as follows::
# Some versions of u-boot build an SPL (Second Program Loader) image that
# should be packaged along with the u-boot binary as well as placed in the
# deploy directory. For those versions they can set the following variables
# to allow packaging the SPL.
SPL_BINARY ?= ""
SPL_BINARYNAME ?= "${@os.path.basename(d.getVar("SPL_BINARY"))}"
SPL_IMAGE ?= "${SPL_BINARYNAME}-${MACHINE}-${PV}-${PR}"
SPL_SYMLINK ?= "${SPL_BINARYNAME}-${MACHINE}"
The :term:`SPL_BINARY` variable helps form
various ``SPL_*`` variables used by the OpenEmbedded build system.
See the BeagleBone machine configuration example in the
":ref:`dev-manual/layers:adding a layer using the \`\`bitbake-layers\`\` script`"
section in the Yocto Project Board Support Package Developer's Guide
for additional information.
:term:`SRCREV_FORMAT`
See :term:`bitbake:SRCREV_FORMAT` in the BitBake manual.
:term:`SRC_URI`
See the BitBake manual for the initial description for this variable:
:term:`bitbake:SRC_URI`.
The following features are added by OpenEmbedded and the Yocto Project.
There are standard and recipe-specific options. Here are standard ones:
- ``apply`` --- whether to apply the patch or not. The default
action is to apply the patch.
- ``striplevel`` --- which striplevel to use when applying the
patch. The default level is 1.
- ``patchdir`` --- specifies the directory in which the patch should
be applied. The default is ``${``\ :term:`S`\ ``}``.
Here are options specific to recipes building code from a revision
control system:
- ``mindate`` --- apply the patch only if
:term:`SRCDATE` is equal to or greater than
``mindate``.
- ``maxdate`` --- apply the patch only if :term:`SRCDATE` is not later
than ``maxdate``.
- ``minrev`` --- apply the patch only if :term:`SRCREV` is equal to or
greater than ``minrev``.
- ``maxrev`` --- apply the patch only if :term:`SRCREV` is not later
than ``maxrev``.
- ``rev`` --- apply the patch only if :term:`SRCREV` is equal to
``rev``.
- ``notrev`` --- apply the patch only if :term:`SRCREV` is not equal to
``rev``.
.. note::
If you want the build system to pick up files specified through
a :term:`SRC_URI` statement from your append file, you need to be
sure to extend the :term:`FILESPATH` variable by also using the
:term:`FILESEXTRAPATHS` variable from within your append file.
:term:`SRC_URI_OVERRIDES_PACKAGE_ARCH`
By default, the OpenEmbedded build system automatically detects
whether :term:`SRC_URI` contains files that are machine-specific. If so,
the build system automatically changes :term:`PACKAGE_ARCH`. Setting this
variable to "0" disables this behavior.
:term:`SRCDATE`
The date of the source code used to build the package. This variable
applies only if the source was fetched from a Source Code Manager
(SCM).
:term:`SRCPV`
Returns the version string of the current package. This string is
used to help define the value of :term:`PV`.
The :term:`SRCPV` variable is defined in the ``meta/conf/bitbake.conf``
configuration file in the :term:`Source Directory` as
follows::
SRCPV = "${@bb.fetch2.get_srcrev(d)}"
Recipes that need to define :term:`PV` do so with the help of the
:term:`SRCPV`. For example, the ``ofono`` recipe (``ofono_git.bb``)
located in ``meta/recipes-connectivity`` in the Source Directory
defines :term:`PV` as follows::
PV = "0.12-git${SRCPV}"
:term:`SRCREV`
The revision of the source code used to build the package. This
variable applies to Subversion, Git, Mercurial, and Bazaar only. Note
that if you want to build a fixed revision and you want to avoid
performing a query on the remote repository every time BitBake parses
your recipe, you should specify a :term:`SRCREV` that is a full revision
identifier and not just a tag.
.. note::
For information on limitations when inheriting the latest revision
of software using :term:`SRCREV`, see the :term:`AUTOREV` variable
description and the
":ref:`dev-manual/packages:automatically incrementing a package version number`"
section, which is in the Yocto Project Development Tasks Manual.
:term:`SRCTREECOVEREDTASKS`
A list of tasks that are typically not relevant (and therefore skipped)
when building using the :ref:`ref-classes-externalsrc`
class. The default value as set in that class file is the set of tasks
that are rarely needed when using external source::
SRCTREECOVEREDTASKS ?= "do_patch do_unpack do_fetch"
The notable exception is when processing external kernel source as
defined in the :ref:`ref-classes-kernel-yocto` class file (formatted for
aesthetics)::
SRCTREECOVEREDTASKS += "\
do_validate_branches \
do_kernel_configcheck \
do_kernel_checkout \
do_fetch \
do_unpack \
do_patch \
"
See the associated :term:`EXTERNALSRC` and :term:`EXTERNALSRC_BUILD`
variables for more information.
:term:`SSTATE_DIR`
The directory for the shared state cache.
:term:`SSTATE_EXCLUDEDEPS_SYSROOT`
This variable allows to specify indirect dependencies to exclude
from sysroots, for example to avoid the situations when a dependency on
any ``-native`` recipe will pull in all dependencies of that recipe
in the recipe sysroot. This behaviour might not always be wanted,
for example when that ``-native`` recipe depends on build tools
that are not relevant for the current recipe.
This way, irrelevant dependencies are ignored, which could have
prevented the reuse of prebuilt artifacts stored in the Shared
State Cache.
:term:`SSTATE_EXCLUDEDEPS_SYSROOT` is evaluated as two regular
expressions of recipe and dependency to ignore. An example
is the rule in :oe_git:`meta/conf/layer.conf </meta/conf/layer.conf>`::
# Nothing needs to depend on libc-initial
# base-passwd/shadow-sysroot don't need their dependencies
SSTATE_EXCLUDEDEPS_SYSROOT += "\
.*->.*-initial.* \
.*(base-passwd|shadow-sysroot)->.* \
"
The ``->`` substring represents the dependency between
the two regular expressions.
:term:`SSTATE_MIRROR_ALLOW_NETWORK`
If set to "1", allows fetches from mirrors that are specified in
:term:`SSTATE_MIRRORS` to work even when
fetching from the network is disabled by setting :term:`BB_NO_NETWORK` to
"1". Using the :term:`SSTATE_MIRROR_ALLOW_NETWORK` variable is useful if
you have set :term:`SSTATE_MIRRORS` to point to an internal server for
your shared state cache, but you want to disable any other fetching
from the network.
:term:`SSTATE_MIRRORS`
Configures the OpenEmbedded build system to search other mirror
locations for prebuilt cache data objects before building out the
data. This variable works like fetcher :term:`MIRRORS`
and :term:`PREMIRRORS` and points to the cache
locations to check for the shared state (sstate) objects.
You can specify a filesystem directory or a remote URL such as HTTP
or FTP. The locations you specify need to contain the shared state
cache (sstate-cache) results from previous builds. The sstate-cache
you point to can also be from builds on other machines.
When pointing to sstate build artifacts on another machine that uses
a different GCC version for native builds, you must configure
:term:`SSTATE_MIRRORS` with a regular expression that maps local search
paths to server paths. The paths need to take into account
:term:`NATIVELSBSTRING` set by the :ref:`ref-classes-uninative` class.
For example, the following maps the local search path ``universal-4.9``
to the server-provided path server_url_sstate_path::
SSTATE_MIRRORS ?= "file://universal-4.9/(.*) https://server_url_sstate_path/universal-4.8/\1"
If a mirror uses the same structure as
:term:`SSTATE_DIR`, you need to add "PATH" at the
end as shown in the examples below. The build system substitutes the
correct path within the directory structure::
SSTATE_MIRRORS ?= "\
file://.* https://someserver.tld/share/sstate/PATH;downloadfilename=PATH \
file://.* file:///some-local-dir/sstate/PATH"
:term:`SSTATE_SCAN_FILES`
Controls the list of files the OpenEmbedded build system scans for
hardcoded installation paths. The variable uses a space-separated
list of filenames (not paths) with standard wildcard characters
allowed.
During a build, the OpenEmbedded build system creates a shared state
(sstate) object during the first stage of preparing the sysroots.
That object is scanned for hardcoded paths for original installation
locations. The list of files that are scanned for paths is controlled
by the :term:`SSTATE_SCAN_FILES` variable. Typically, recipes add files
they want to be scanned to the value of :term:`SSTATE_SCAN_FILES` rather
than the variable being comprehensively set. The
:ref:`ref-classes-sstate` class specifies the default list of files.
For details on the process, see the :ref:`ref-classes-staging` class.
:term:`STAGING_BASE_LIBDIR_NATIVE`
Specifies the path to the ``/lib`` subdirectory of the sysroot
directory for the build host.
:term:`STAGING_BASELIBDIR`
Specifies the path to the ``/lib`` subdirectory of the sysroot
directory for the target for which the current recipe is being built
(:term:`STAGING_DIR_HOST`).
:term:`STAGING_BINDIR`
Specifies the path to the ``/usr/bin`` subdirectory of the sysroot
directory for the target for which the current recipe is being built
(:term:`STAGING_DIR_HOST`).
:term:`STAGING_BINDIR_CROSS`
Specifies the path to the directory containing binary configuration
scripts. These scripts provide configuration information for other
software that wants to make use of libraries or include files
provided by the software associated with the script.
.. note::
This style of build configuration has been largely replaced by
``pkg-config``. Consequently, if ``pkg-config`` is supported by the
library to which you are linking, it is recommended you use
``pkg-config`` instead of a provided configuration script.
:term:`STAGING_BINDIR_NATIVE`
Specifies the path to the ``/usr/bin`` subdirectory of the sysroot
directory for the build host.
:term:`STAGING_DATADIR`
Specifies the path to the ``/usr/share`` subdirectory of the sysroot
directory for the target for which the current recipe is being built
(:term:`STAGING_DIR_HOST`).
:term:`STAGING_DATADIR_NATIVE`
Specifies the path to the ``/usr/share`` subdirectory of the sysroot
directory for the build host.
:term:`STAGING_DIR`
Helps construct the ``recipe-sysroots`` directory, which is used
during packaging.
For information on how staging for recipe-specific sysroots occurs,
see the :ref:`ref-tasks-populate_sysroot`
task, the ":ref:`sdk-manual/extensible:sharing files between recipes`"
section in the Yocto Project Development Tasks Manual, the
":ref:`overview-manual/concepts:configuration, compilation, and staging`"
section in the Yocto Project Overview and Concepts Manual, and the
:term:`SYSROOT_DIRS` variable.
.. note::
Recipes should never write files directly under the :term:`STAGING_DIR`
directory because the OpenEmbedded build system manages the
directory automatically. Instead, files should be installed to
``${``\ :term:`D`\ ``}`` within your recipe's :ref:`ref-tasks-install`
task and then the OpenEmbedded build system will stage a subset of
those files into the sysroot.
:term:`STAGING_DIR_HOST`
Specifies the path to the sysroot directory for the system on which
the component is built to run (the system that hosts the component).
For most recipes, this sysroot is the one in which that recipe's
:ref:`ref-tasks-populate_sysroot` task copies
files. Exceptions include ``-native`` recipes, where the
:ref:`ref-tasks-populate_sysroot` task instead uses
:term:`STAGING_DIR_NATIVE`. Depending on
the type of recipe and the build target, :term:`STAGING_DIR_HOST` can
have the following values:
- For recipes building for the target machine, the value is
"${:term:`STAGING_DIR`}/${:term:`MACHINE`}".
- For native recipes building for the build host, the value is empty
given the assumption that when building for the build host, the
build host's own directories should be used.
.. note::
``-native`` recipes are not installed into host paths like such
as ``/usr``. Rather, these recipes are installed into
:term:`STAGING_DIR_NATIVE`. When compiling ``-native`` recipes,
standard build environment variables such as
:term:`CPPFLAGS` and
:term:`CFLAGS` are set up so that both host paths
and :term:`STAGING_DIR_NATIVE` are searched for libraries and
headers using, for example, GCC's ``-isystem`` option.
Thus, the emphasis is that the ``STAGING_DIR*`` variables
should be viewed as input variables by tasks such as
:ref:`ref-tasks-configure`,
:ref:`ref-tasks-compile`, and
:ref:`ref-tasks-install`. Having the real system
root correspond to :term:`STAGING_DIR_HOST` makes conceptual sense
for ``-native`` recipes, as they make use of host headers and
libraries.
:term:`STAGING_DIR_NATIVE`
Specifies the path to the sysroot directory used when building
components that run on the build host itself.
:term:`STAGING_DIR_TARGET`
Specifies the path to the sysroot used for the system for which the
component generates code. For components that do not generate code,
which is the majority, :term:`STAGING_DIR_TARGET` is set to match
:term:`STAGING_DIR_HOST`.
Some recipes build binaries that can run on the target system but those
binaries in turn generate code for another different system (e.g.
:ref:`ref-classes-cross-canadian` recipes). Using terminology from GNU,
the primary system is referred to as the "HOST" and the secondary, or
different, system is referred to as the "TARGET". Thus, the binaries
run on the "HOST" system and generate binaries for the "TARGET"
system. The :term:`STAGING_DIR_HOST` variable points to the sysroot used
for the "HOST" system, while :term:`STAGING_DIR_TARGET` points to the
sysroot used for the "TARGET" system.
:term:`STAGING_ETCDIR_NATIVE`
Specifies the path to the ``/etc`` subdirectory of the sysroot
directory for the build host.
:term:`STAGING_EXECPREFIXDIR`
Specifies the path to the ``/usr`` subdirectory of the sysroot
directory for the target for which the current recipe is being built
(:term:`STAGING_DIR_HOST`).
:term:`STAGING_INCDIR`
Specifies the path to the ``/usr/include`` subdirectory of the
sysroot directory for the target for which the current recipe being
built (:term:`STAGING_DIR_HOST`).
:term:`STAGING_INCDIR_NATIVE`
Specifies the path to the ``/usr/include`` subdirectory of the
sysroot directory for the build host.
:term:`STAGING_KERNEL_BUILDDIR`
Points to the directory containing the kernel build artifacts.
Recipes building software that needs to access kernel build artifacts
(e.g. ``systemtap-uprobes``) can look in the directory specified with
the :term:`STAGING_KERNEL_BUILDDIR` variable to find these artifacts
after the kernel has been built.
:term:`STAGING_KERNEL_DIR`
The directory with kernel headers that are required to build
out-of-tree modules.
:term:`STAGING_LIBDIR`
Specifies the path to the ``/usr/lib`` subdirectory of the sysroot
directory for the target for which the current recipe is being built
(:term:`STAGING_DIR_HOST`).
:term:`STAGING_LIBDIR_NATIVE`
Specifies the path to the ``/usr/lib`` subdirectory of the sysroot
directory for the build host.
:term:`STAMP`
Specifies the base path used to create recipe stamp files. The path
to an actual stamp file is constructed by evaluating this string and
then appending additional information. Currently, the default
assignment for :term:`STAMP` as set in the ``meta/conf/bitbake.conf``
file is::
STAMP = "${STAMPS_DIR}/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}"
For information on how BitBake uses stamp files to determine if a
task should be rerun, see the
":ref:`overview-manual/concepts:stamp files and the rerunning of tasks`"
section in the Yocto Project Overview and Concepts Manual.
See :term:`STAMPS_DIR`,
:term:`MULTIMACH_TARGET_SYS`,
:term:`PN`, :term:`EXTENDPE`,
:term:`PV`, and :term:`PR` for related variable
information.
:term:`STAMPCLEAN`
See :term:`bitbake:STAMPCLEAN` in the BitBake manual.
:term:`STAMPS_DIR`
Specifies the base directory in which the OpenEmbedded build system
places stamps. The default directory is ``${TMPDIR}/stamps``.
:term:`STRIP`
The minimal command and arguments to run ``strip``, which is used to
strip symbols.
:term:`SUMMARY`
The short (72 characters or less) summary of the binary package for
packaging systems such as ``opkg``, ``rpm``, or ``dpkg``. By default,
:term:`SUMMARY` is used to define the
:term:`DESCRIPTION` variable if :term:`DESCRIPTION` is
not set in the recipe.
:term:`SVNDIR`
The directory in which files checked out of a Subversion system are
stored.
:term:`SYSLINUX_DEFAULT_CONSOLE`
Specifies the kernel boot default console. If you want to use a
console other than the default, set this variable in your recipe as
follows where "X" is the console number you want to use::
SYSLINUX_DEFAULT_CONSOLE = "console=ttyX"
The :ref:`ref-classes-syslinux` class initially sets
this variable to null but then checks for a value later.
:term:`SYSLINUX_OPTS`
Lists additional options to add to the syslinux file. You need to set
this variable in your recipe. If you want to list multiple options,
separate the options with a semicolon character (``;``).
The :ref:`ref-classes-syslinux` class uses this variable
to create a set of options.
:term:`SYSLINUX_SERIAL`
Specifies the alternate serial port or turns it off. To turn off
serial, set this variable to an empty string in your recipe. The
variable's default value is set in the
:ref:`ref-classes-syslinux` class as follows::
SYSLINUX_SERIAL ?= "0 115200"
The class checks for and uses the variable as needed.
:term:`SYSLINUX_SERIAL_TTY`
Specifies the alternate console=tty... kernel boot argument. The
variable's default value is set in the :ref:`ref-classes-syslinux`
class as follows::
SYSLINUX_SERIAL_TTY ?= "console=ttyS0,115200"
The class checks for and uses the variable as needed.
:term:`SYSLINUX_SPLASH`
An ``.LSS`` file used as the background for the VGA boot menu when
you use the boot menu. You need to set this variable in your recipe.
The :ref:`ref-classes-syslinux` class checks for this
variable and if found, the OpenEmbedded build system installs the
splash screen.
:term:`SYSROOT_DESTDIR`
Points to the temporary directory under the work directory (default
"``${``\ :term:`WORKDIR`\ ``}/sysroot-destdir``")
where the files populated into the sysroot are assembled during the
:ref:`ref-tasks-populate_sysroot` task.
:term:`SYSROOT_DIRS`
Directories that are staged into the sysroot by the
:ref:`ref-tasks-populate_sysroot` task. By
default, the following directories are staged::
SYSROOT_DIRS = " \
${includedir} \
${libdir} \
${base_libdir} \
${nonarch_base_libdir} \
${datadir} \
/sysroot-only \
"
:term:`SYSROOT_DIRS_IGNORE`
Directories that are not staged into the sysroot by the
:ref:`ref-tasks-populate_sysroot` task. You
can use this variable to exclude certain subdirectories of
directories listed in :term:`SYSROOT_DIRS` from
staging. By default, the following directories are not staged::
SYSROOT_DIRS_IGNORE = " \
${mandir} \
${docdir} \
${infodir} \
${datadir}/X11/locale \
${datadir}/applications \
${datadir}/bash-completion \
${datadir}/fonts \
${datadir}/gtk-doc/html \
${datadir}/installed-tests \
${datadir}/locale \
${datadir}/pixmaps \
${datadir}/terminfo \
${libdir}/${BPN}/ptest \
"
:term:`SYSROOT_DIRS_NATIVE`
Extra directories staged into the sysroot by the
:ref:`ref-tasks-populate_sysroot` task for
``-native`` recipes, in addition to those specified in
:term:`SYSROOT_DIRS`. By default, the following
extra directories are staged::
SYSROOT_DIRS_NATIVE = " \
${bindir} \
${sbindir} \
${base_bindir} \
${base_sbindir} \
${libexecdir} \
${sysconfdir} \
${localstatedir} \
"
.. note::
Programs built by ``-native`` recipes run directly from the sysroot
(:term:`STAGING_DIR_NATIVE`), which is why additional directories
containing program executables and supporting files need to be staged.
:term:`SYSROOT_PREPROCESS_FUNCS`
A list of functions to execute after files are staged into the
sysroot. These functions are usually used to apply additional
processing on the staged files, or to stage additional files.
:term:`SYSTEMD_AUTO_ENABLE`
When inheriting the :ref:`ref-classes-systemd` class,
this variable specifies whether the specified service in
:term:`SYSTEMD_SERVICE` should start
automatically or not. By default, the service is enabled to
automatically start at boot time. The default setting is in the
:ref:`ref-classes-systemd` class as follows::
SYSTEMD_AUTO_ENABLE ??= "enable"
You can disable the service by setting the variable to "disable".
:term:`SYSTEMD_BOOT_CFG`
When :term:`EFI_PROVIDER` is set to
"systemd-boot", the :term:`SYSTEMD_BOOT_CFG` variable specifies the
configuration file that should be used. By default, the
:ref:`ref-classes-systemd-boot` class sets the
:term:`SYSTEMD_BOOT_CFG` as follows::
SYSTEMD_BOOT_CFG ?= "${S}/loader.conf"
For information on Systemd-boot, see the `Systemd-boot
documentation <https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
:term:`SYSTEMD_BOOT_ENTRIES`
When :term:`EFI_PROVIDER` is set to
"systemd-boot", the :term:`SYSTEMD_BOOT_ENTRIES` variable specifies a
list of entry files (``*.conf``) to install that contain one boot
entry per file. By default, the :ref:`ref-classes-systemd-boot` class
sets the :term:`SYSTEMD_BOOT_ENTRIES` as follows::
SYSTEMD_BOOT_ENTRIES ?= ""
For information on Systemd-boot, see the `Systemd-boot
documentation <https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
:term:`SYSTEMD_BOOT_TIMEOUT`
When :term:`EFI_PROVIDER` is set to
"systemd-boot", the :term:`SYSTEMD_BOOT_TIMEOUT` variable specifies the
boot menu timeout in seconds. By default, the
:ref:`ref-classes-systemd-boot` class sets the
:term:`SYSTEMD_BOOT_TIMEOUT` as follows::
SYSTEMD_BOOT_TIMEOUT ?= "10"
For information on Systemd-boot, see the `Systemd-boot
documentation <https://www.freedesktop.org/wiki/Software/systemd/systemd-boot/>`__.
:term:`SYSTEMD_DEFAULT_TARGET`
This variable allows to set the default unit that systemd starts at bootup.
Usually, this is either ``multi-user.target`` or ``graphical.target``.
This works by creating a ``default.target`` symbolic link to the chosen systemd
target file.
See `systemd's documentation
<https://www.freedesktop.org/software/systemd/man/systemd.special.html>`__
for details.
For example, this variable is used in the :oe_git:`core-image-minimal-xfce.bb
</meta-openembedded/tree/meta-xfce/recipes-core/images/core-image-minimal-xfce.bb>`
recipe::
SYSTEMD_DEFAULT_TARGET = "graphical.target"
:term:`SYSTEMD_PACKAGES`
When inheriting the :ref:`ref-classes-systemd` class,
this variable locates the systemd unit files when they are not found
in the main recipe's package. By default, the :term:`SYSTEMD_PACKAGES`
variable is set such that the systemd unit files are assumed to
reside in the recipes main package::
SYSTEMD_PACKAGES ?= "${PN}"
If these unit files are not in this recipe's main package, you need
to use :term:`SYSTEMD_PACKAGES` to list the package or packages in which
the build system can find the systemd unit files.
:term:`SYSTEMD_SERVICE`
When inheriting the :ref:`ref-classes-systemd` class,
this variable specifies the systemd service name for a package.
Multiple services can be specified, each one separated by a space.
When you specify this file in your recipe, use a package name
override to indicate the package to which the value applies. Here is
an example from the connman recipe::
SYSTEMD_SERVICE:${PN} = "connman.service"
The package overrides that can be specified are directly related to the value of
:term:`SYSTEMD_PACKAGES`. Overrides not included in :term:`SYSTEMD_PACKAGES`
will be silently ignored.
:term:`SYSVINIT_ENABLED_GETTYS`
When using
:ref:`SysVinit <dev-manual/new-recipe:enabling system services>`,
specifies a space-separated list of the virtual terminals that should
run a `getty <https://en.wikipedia.org/wiki/Getty_%28Unix%29>`__
(allowing login), assuming :term:`USE_VT` is not set to
"0".
The default value for :term:`SYSVINIT_ENABLED_GETTYS` is "1" (i.e. only
run a getty on the first virtual terminal).
:term:`T`
This variable points to a directory were BitBake places temporary
files, which consist mostly of task logs and scripts, when building a
particular recipe. The variable is typically set as follows::
T = "${WORKDIR}/temp"
The :term:`WORKDIR` is the directory into which
BitBake unpacks and builds the recipe. The default ``bitbake.conf``
file sets this variable.
The :term:`T` variable is not to be confused with the
:term:`TMPDIR` variable, which points to the root of
the directory tree where BitBake places the output of an entire
build.
:term:`TARGET_ARCH`
The target machine's architecture. The OpenEmbedded build system
supports many architectures. Here is an example list of architectures
supported. This list is by no means complete as the architecture is
configurable:
- arm
- i586
- x86_64
- powerpc
- powerpc64
- mips
- mipsel
For additional information on machine architectures, see the
:term:`TUNE_ARCH` variable.
:term:`TARGET_AS_ARCH`
Specifies architecture-specific assembler flags for the target
system. :term:`TARGET_AS_ARCH` is initialized from
:term:`TUNE_ASARGS` by default in the BitBake
configuration file (``meta/conf/bitbake.conf``)::
TARGET_AS_ARCH = "${TUNE_ASARGS}"
:term:`TARGET_CC_ARCH`
Specifies architecture-specific C compiler flags for the target
system. :term:`TARGET_CC_ARCH` is initialized from
:term:`TUNE_CCARGS` by default.
.. note::
It is a common workaround to append :term:`LDFLAGS` to
:term:`TARGET_CC_ARCH` in recipes that build software for the target that
would not otherwise respect the exported :term:`LDFLAGS` variable.
:term:`TARGET_CC_KERNEL_ARCH`
This is a specific kernel compiler flag for a CPU or Application
Binary Interface (ABI) tune. The flag is used rarely and only for
cases where a userspace :term:`TUNE_CCARGS` is not
compatible with the kernel compilation. The :term:`TARGET_CC_KERNEL_ARCH`
variable allows the kernel (and associated modules) to use a
different configuration. See the
``meta/conf/machine/include/arm/feature-arm-thumb.inc`` file in the
:term:`Source Directory` for an example.
:term:`TARGET_CFLAGS`
Specifies the flags to pass to the C compiler when building for the
target. When building in the target context,
:term:`CFLAGS` is set to the value of this variable by
default.
Additionally, the SDK's environment setup script sets the :term:`CFLAGS`
variable in the environment to the :term:`TARGET_CFLAGS` value so that
executables built using the SDK also have the flags applied.
:term:`TARGET_CPPFLAGS`
Specifies the flags to pass to the C pre-processor (i.e. to both the
C and the C++ compilers) when building for the target. When building
in the target context, :term:`CPPFLAGS` is set to the
value of this variable by default.
Additionally, the SDK's environment setup script sets the
:term:`CPPFLAGS` variable in the environment to the :term:`TARGET_CPPFLAGS`
value so that executables built using the SDK also have the flags
applied.
:term:`TARGET_CXXFLAGS`
Specifies the flags to pass to the C++ compiler when building for the
target. When building in the target context,
:term:`CXXFLAGS` is set to the value of this variable
by default.
Additionally, the SDK's environment setup script sets the
:term:`CXXFLAGS` variable in the environment to the :term:`TARGET_CXXFLAGS`
value so that executables built using the SDK also have the flags
applied.
:term:`TARGET_FPU`
Specifies the method for handling FPU code. For FPU-less targets,
which include most ARM CPUs, the variable must be set to "soft". If
not, the kernel emulation gets used, which results in a performance
penalty.
:term:`TARGET_LD_ARCH`
Specifies architecture-specific linker flags for the target system.
:term:`TARGET_LD_ARCH` is initialized from
:term:`TUNE_LDARGS` by default in the BitBake
configuration file (``meta/conf/bitbake.conf``)::
TARGET_LD_ARCH = "${TUNE_LDARGS}"
:term:`TARGET_LDFLAGS`
Specifies the flags to pass to the linker when building for the
target. When building in the target context,
:term:`LDFLAGS` is set to the value of this variable
by default.
Additionally, the SDK's environment setup script sets the
:term:`LDFLAGS` variable in the environment to the
:term:`TARGET_LDFLAGS` value so that executables built using the SDK also
have the flags applied.
:term:`TARGET_OS`
Specifies the target's operating system. The variable can be set to
"linux" for glibc-based systems (GNU C Library) and to "linux-musl"
for musl libc. For ARM/EABI targets, the possible values are
"linux-gnueabi" and "linux-musleabi".
:term:`TARGET_PREFIX`
Specifies the prefix used for the toolchain binary target tools.
Depending on the type of recipe and the build target,
:term:`TARGET_PREFIX` is set as follows:
- For recipes building for the target machine, the value is
"${:term:`TARGET_SYS`}-".
- For native recipes, the build system sets the variable to the
value of :term:`BUILD_PREFIX`.
- For native SDK recipes (:ref:`ref-classes-nativesdk`),
the build system sets the variable to the value of :term:`SDK_PREFIX`.
:term:`TARGET_SYS`
Specifies the system, including the architecture and the operating
system, for which the build is occurring in the context of the
current recipe.
The OpenEmbedded build system automatically sets this variable based
on :term:`TARGET_ARCH`,
:term:`TARGET_VENDOR`, and
:term:`TARGET_OS` variables.
.. note::
You do not need to set the :term:`TARGET_SYS` variable yourself.
Consider these two examples:
- Given a native recipe on a 32-bit, x86 machine running Linux, the
value is "i686-linux".
- Given a recipe being built for a little-endian, MIPS target
running Linux, the value might be "mipsel-linux".
:term:`TARGET_VENDOR`
Specifies the name of the target vendor.
:term:`TCLIBC`
Specifies the GNU standard C library (``libc``) variant to use during
the build process.
You can select "glibc", "musl", "newlib", or "baremetal".
:term:`TCLIBCAPPEND`
Specifies a suffix to be appended onto the :term:`TMPDIR` value. The
suffix identifies the ``libc`` variant for building. When you are
building for multiple variants with the same :term:`Build Directory`,
this mechanism ensures that output for different ``libc`` variants is
kept separate to avoid potential conflicts.
In the ``defaultsetup.conf`` file, the default value of
:term:`TCLIBCAPPEND` is "-${TCLIBC}". However, distros such as poky,
which normally only support one ``libc`` variant, set
:term:`TCLIBCAPPEND` to "" in their distro configuration file resulting
in no suffix being applied.
:term:`TCMODE`
Specifies the toolchain selector. :term:`TCMODE` controls the
characteristics of the generated packages and images by telling the
OpenEmbedded build system which toolchain profile to use. By default,
the OpenEmbedded build system builds its own internal toolchain. The
variable's default value is "default", which uses that internal
toolchain.
.. note::
If :term:`TCMODE` is set to a value other than "default", then it is your
responsibility to ensure that the toolchain is compatible with the
default toolchain. Using older or newer versions of these
components might cause build problems. See
:yocto_docs:`Release Information </migration-guides/>` for your
version of the Yocto Project, to find the specific components with
which the toolchain must be compatible.
The :term:`TCMODE` variable is similar to :term:`TCLIBC`,
which controls the variant of the GNU standard C library (``libc``)
used during the build process: ``glibc`` or ``musl``.
With additional layers, it is possible to use a pre-compiled external
toolchain. One example is the Sourcery G++ Toolchain. The support for
this toolchain resides in the separate Mentor Graphics
``meta-sourcery`` layer at
https://github.com/MentorEmbedded/meta-sourcery/.
The layer's ``README`` file contains information on how to use the
Sourcery G++ Toolchain as an external toolchain. You will have to
add the layer to your ``bblayers.conf`` file and then set the
:term:`EXTERNAL_TOOLCHAIN` variable in your ``local.conf`` file to
the location of the toolchain.
The fundamentals used for this example apply to any external
toolchain. You can use ``meta-sourcery`` as a template for adding
support for other external toolchains.
In addition to toolchain configuration, you will also need a
corresponding toolchain recipe file. This recipe file needs to package
up any pre-built objects in the toolchain such as ``libgcc``,
``libstdcc++``, any locales, and ``libc``.
:term:`TC_CXX_RUNTIME`
Specifies the C/C++ STL and runtime variant to use during
the build process. Default value is 'gnu'
You can select "gnu", "llvm", or "android".
:term:`TEMPLATECONF`
Specifies the directory used by the build system to find templates
from which to build the ``bblayers.conf`` and ``local.conf`` files.
Use this variable if you wish to customize such files, and the default
BitBake targets shown when sourcing the ``oe-init-build-env`` script.
For details, see the
:ref:`dev-manual/custom-template-configuration-directory:creating a custom template configuration directory`
section in the Yocto Project Development Tasks manual.
.. note::
You must set this variable in the external environment in order
for it to work.
:term:`TEST_EXPORT_DIR`
The location the OpenEmbedded build system uses to export tests when
the :term:`TEST_EXPORT_ONLY` variable is set
to "1".
The :term:`TEST_EXPORT_DIR` variable defaults to
``"${TMPDIR}/testimage/${PN}"``.
:term:`TEST_EXPORT_ONLY`
Specifies to export the tests only. Set this variable to "1" if you
do not want to run the tests but you want them to be exported in a
manner that you to run them outside of the build system.
:term:`TEST_LOG_DIR`
Holds the SSH log and the boot log for QEMU machines. The
:term:`TEST_LOG_DIR` variable defaults to ``"${WORKDIR}/testimage"``.
.. note::
Actual test results reside in the task log (``log.do_testimage``),
which is in the ``${WORKDIR}/temp/`` directory.
:term:`TEST_POWERCONTROL_CMD`
For automated hardware testing, specifies the command to use to
control the power of the target machine under test. Typically, this
command would point to a script that performs the appropriate action
(e.g. interacting with a web-enabled power strip). The specified
command should expect to receive as the last argument "off", "on" or
"cycle" specifying to power off, on, or cycle (power off and then
power on) the device, respectively.
:term:`TEST_POWERCONTROL_EXTRA_ARGS`
For automated hardware testing, specifies additional arguments to
pass through to the command specified in
:term:`TEST_POWERCONTROL_CMD`. Setting
:term:`TEST_POWERCONTROL_EXTRA_ARGS` is optional. You can use it if you
wish, for example, to separate the machine-specific and
non-machine-specific parts of the arguments.
:term:`TEST_QEMUBOOT_TIMEOUT`
The time in seconds allowed for an image to boot before automated
runtime tests begin to run against an image. The default timeout
period to allow the boot process to reach the login prompt is 500
seconds. You can specify a different value in the ``local.conf``
file.
For more information on testing images, see the
":ref:`dev-manual/runtime-testing:performing automated runtime testing`"
section in the Yocto Project Development Tasks Manual.
:term:`TEST_SERIALCONTROL_CMD`
For automated hardware testing, specifies the command to use to
connect to the serial console of the target machine under test. This
command simply needs to connect to the serial console and forward
that connection to standard input and output as any normal terminal
program does.
For example, to use the Picocom terminal program on serial device
``/dev/ttyUSB0`` at 115200bps, you would set the variable as follows::
TEST_SERIALCONTROL_CMD = "picocom /dev/ttyUSB0 -b 115200"
:term:`TEST_SERIALCONTROL_EXTRA_ARGS`
For automated hardware testing, specifies additional arguments to
pass through to the command specified in
:term:`TEST_SERIALCONTROL_CMD`. Setting
:term:`TEST_SERIALCONTROL_EXTRA_ARGS` is optional. You can use it if you
wish, for example, to separate the machine-specific and
non-machine-specific parts of the command.
:term:`TEST_SERVER_IP`
The IP address of the build machine (host machine). This IP address
is usually automatically detected. However, if detection fails, this
variable needs to be set to the IP address of the build machine (i.e.
where the build is taking place).
.. note::
The :term:`TEST_SERVER_IP` variable is only used for a small number of
tests such as the "dnf" test suite, which needs to download packages
from ``WORKDIR/oe-rootfs-repo``.
:term:`TEST_SUITES`
An ordered list of tests (modules) to run against an image when
performing automated runtime testing.
The OpenEmbedded build system provides a core set of tests that can
be used against images.
.. note::
Currently, there is only support for running these tests under
QEMU.
Tests include ``ping``, ``ssh``, ``df`` among others. You can add
your own tests to the list of tests by appending :term:`TEST_SUITES` as
follows::
TEST_SUITES:append = " mytest"
Alternatively, you can
provide the "auto" option to have all applicable tests run against
the image::
TEST_SUITES:append = " auto"
Using this option causes the
build system to automatically run tests that are applicable to the
image. Tests that are not applicable are skipped.
The order in which tests are run is important. Tests that depend on
another test must appear later in the list than the test on which
they depend. For example, if you append the list of tests with two
tests (``test_A`` and ``test_B``) where ``test_B`` is dependent on
``test_A``, then you must order the tests as follows::
TEST_SUITES = "test_A test_B"
For more information on testing images, see the
":ref:`dev-manual/runtime-testing:performing automated runtime testing`"
section in the Yocto Project Development Tasks Manual.
:term:`TEST_TARGET`
Specifies the target controller to use when running tests against a
test image. The default controller to use is "qemu"::
TEST_TARGET = "qemu"
A target controller is a class that defines how an image gets
deployed on a target and how a target is started. A layer can extend
the controllers by adding a module in the layer's
``/lib/oeqa/controllers`` directory and by inheriting the
``BaseTarget`` class, which is an abstract class that cannot be used
as a value of :term:`TEST_TARGET`.
You can provide the following arguments with :term:`TEST_TARGET`:
- *"qemu":* Boots a QEMU image and runs the tests. See the
":ref:`dev-manual/runtime-testing:enabling runtime tests on qemu`" section
in the Yocto Project Development Tasks Manual for more
information.
- *"simpleremote":* Runs the tests on target hardware that is
already up and running. The hardware can be on the network or it
can be a device running an image on QEMU. You must also set
:term:`TEST_TARGET_IP` when you use
"simpleremote".
.. note::
This argument is defined in
``meta/lib/oeqa/controllers/simpleremote.py``.
For information on running tests on hardware, see the
":ref:`dev-manual/runtime-testing:enabling runtime tests on hardware`"
section in the Yocto Project Development Tasks Manual.
:term:`TEST_TARGET_IP`
The IP address of your hardware under test. The :term:`TEST_TARGET_IP`
variable has no effect when :term:`TEST_TARGET` is
set to "qemu".
When you specify the IP address, you can also include a port. Here is
an example::
TEST_TARGET_IP = "192.168.1.4:2201"
Specifying a port is
useful when SSH is started on a non-standard port or in cases when
your hardware under test is behind a firewall or network that is not
directly accessible from your host and you need to do port address
translation.
:term:`TESTIMAGE_AUTO`
Automatically runs the series of automated tests for images when an
image is successfully built. Setting :term:`TESTIMAGE_AUTO` to "1" causes
any image that successfully builds to automatically boot under QEMU.
Using the variable also adds in dependencies so that any SDK for
which testing is requested is automatically built first.
These tests are written in Python making use of the ``unittest``
module, and the majority of them run commands on the target system
over ``ssh``. You can set this variable to "1" in your ``local.conf``
file in the :term:`Build Directory` to have the
OpenEmbedded build system automatically run these tests after an
image successfully builds:
TESTIMAGE_AUTO = "1"
For more information
on enabling, running, and writing these tests, see the
":ref:`dev-manual/runtime-testing:performing automated runtime testing`"
section in the Yocto Project Development Tasks Manual and the
":ref:`ref-classes-testimage`" section.
:term:`THISDIR`
The directory in which the file BitBake is currently parsing is
located. Do not manually set this variable.
:term:`TIME`
The time the build was started. Times appear using the hour, minute,
and second (HMS) format (e.g. "140159" for one minute and fifty-nine
seconds past 1400 hours).
:term:`TMPDIR`
This variable is the base directory the OpenEmbedded build system
uses for all build output and intermediate files (other than the
shared state cache). By default, the :term:`TMPDIR` variable points to
``tmp`` within the :term:`Build Directory`.
If you want to establish this directory in a location other than the
default, you can uncomment and edit the following statement in the
``conf/local.conf`` file in the :term:`Source Directory`::
#TMPDIR = "${TOPDIR}/tmp"
An example use for this scenario is to set :term:`TMPDIR` to a local disk,
which does not use NFS, while having the :term:`Build Directory` use NFS.
The filesystem used by :term:`TMPDIR` must have standard filesystem
semantics (i.e. mixed-case files are unique, POSIX file locking, and
persistent inodes). Due to various issues with NFS and bugs in some
implementations, NFS does not meet this minimum requirement.
Consequently, :term:`TMPDIR` cannot be on NFS.
:term:`TOOLCHAIN_HOST_TASK`
This variable lists packages the OpenEmbedded build system uses when
building an SDK, which contains a cross-development environment. The
packages specified by this variable are part of the toolchain set
that runs on the :term:`SDKMACHINE`, and each
package should usually have the prefix ``nativesdk-``. For example,
consider the following command when building an SDK::
$ bitbake -c populate_sdk imagename
In this case, a default list of packages is
set in this variable, but you can add additional packages to the
list. See the
":ref:`sdk-manual/appendix-customizing-standard:adding individual packages to the standard sdk`" section
in the Yocto Project Application Development and the Extensible
Software Development Kit (eSDK) manual for more information.
For background information on cross-development toolchains in the
Yocto Project development environment, see the
":ref:`sdk-manual/intro:the cross-development toolchain`"
section in the Yocto Project Overview and Concepts Manual. For
information on setting up a cross-development environment, see the
:doc:`/sdk-manual/index` manual.
Note that this variable applies to building an SDK, not an eSDK,
in which case the :term:`TOOLCHAIN_HOST_TASK_ESDK` setting should be
used instead.
:term:`TOOLCHAIN_HOST_TASK_ESDK`
This variable allows to extend what is installed in the host
portion of an eSDK. This is similar to :term:`TOOLCHAIN_HOST_TASK`
applying to SDKs.
:term:`TOOLCHAIN_OUTPUTNAME`
This variable defines the name used for the toolchain output. The
:ref:`populate_sdk_base <ref-classes-populate-sdk-*>` class sets
the :term:`TOOLCHAIN_OUTPUTNAME` variable as follows::
TOOLCHAIN_OUTPUTNAME ?= "${SDK_NAME}-toolchain-${SDK_VERSION}"
See
the :term:`SDK_NAME` and
:term:`SDK_VERSION` variables for additional
information.
:term:`TOOLCHAIN_TARGET_TASK`
This variable lists packages the OpenEmbedded build system uses when
it creates the target part of an SDK (i.e. the part built for the
target hardware), which includes libraries and headers. Use this
variable to add individual packages to the part of the SDK that runs
on the target. See the
":ref:`sdk-manual/appendix-customizing-standard:adding individual packages to the standard sdk`" section
in the Yocto Project Application Development and the Extensible
Software Development Kit (eSDK) manual for more information.
For background information on cross-development toolchains in the
Yocto Project development environment, see the
":ref:`sdk-manual/intro:the cross-development toolchain`"
section in the Yocto Project Overview and Concepts Manual. For
information on setting up a cross-development environment, see the
:doc:`/sdk-manual/index` manual.
:term:`TOPDIR`
See :term:`bitbake:TOPDIR` in the BitBake manual.
:term:`TRANSLATED_TARGET_ARCH`
A sanitized version of :term:`TARGET_ARCH`. This
variable is used where the architecture is needed in a value where
underscores are not allowed, for example within package filenames. In
this case, dash characters replace any underscore characters used in
:term:`TARGET_ARCH`.
Do not edit this variable.
:term:`TUNE_ARCH`
The GNU canonical architecture for a specific architecture (i.e.
``arm``, ``armeb``, ``mips``, ``mips64``, and so forth). BitBake uses
this value to setup configuration.
:term:`TUNE_ARCH` definitions are specific to a given architecture. The
definitions can be a single static definition, or can be dynamically
adjusted. You can see details for a given CPU family by looking at
the architecture's ``README`` file. For example, the
``meta/conf/machine/include/mips/README`` file in the
:term:`Source Directory` provides information for
:term:`TUNE_ARCH` specific to the ``mips`` architecture.
:term:`TUNE_ARCH` is tied closely to
:term:`TARGET_ARCH`, which defines the target
machine's architecture. The BitBake configuration file
(``meta/conf/bitbake.conf``) sets :term:`TARGET_ARCH` as follows::
TARGET_ARCH = "${TUNE_ARCH}"
The following list, which is by no means complete since architectures
are configurable, shows supported machine architectures:
- arm
- i586
- x86_64
- powerpc
- powerpc64
- mips
- mipsel
:term:`TUNE_ASARGS`
Specifies architecture-specific assembler flags for the target
system. The set of flags is based on the selected tune features.
:term:`TUNE_ASARGS` is set using the tune include files, which are
typically under ``meta/conf/machine/include/`` and are influenced
through :term:`TUNE_FEATURES`. For example, the
``meta/conf/machine/include/x86/arch-x86.inc`` file defines the flags
for the x86 architecture as follows::
TUNE_ASARGS += "${@bb.utils.contains("TUNE_FEATURES", "mx32", "-x32", "", d)}"
.. note::
Board Support Packages (BSPs) select the tune. The selected tune,
in turn, affects the tune variables themselves (i.e. the tune can
supply its own set of flags).
:term:`TUNE_CCARGS`
Specifies architecture-specific C compiler flags for the target
system. The set of flags is based on the selected tune features.
:term:`TUNE_CCARGS` is set using the tune include files, which are
typically under ``meta/conf/machine/include/`` and are influenced
through :term:`TUNE_FEATURES`.
.. note::
Board Support Packages (BSPs) select the tune. The selected tune,
in turn, affects the tune variables themselves (i.e. the tune can
supply its own set of flags).
:term:`TUNE_FEATURES`
Features used to "tune" a compiler for optimal use given a specific
processor. The features are defined within the tune files and allow
arguments (i.e. ``TUNE_*ARGS``) to be dynamically generated based on
the features.
The OpenEmbedded build system verifies the features to be sure they
are not conflicting and that they are supported.
The BitBake configuration file (``meta/conf/bitbake.conf``) defines
:term:`TUNE_FEATURES` as follows::
TUNE_FEATURES ??= "${TUNE_FEATURES:tune-${DEFAULTTUNE}}"
See the :term:`DEFAULTTUNE` variable for more information.
:term:`TUNE_LDARGS`
Specifies architecture-specific linker flags for the target system.
The set of flags is based on the selected tune features.
:term:`TUNE_LDARGS` is set using the tune include files, which are
typically under ``meta/conf/machine/include/`` and are influenced
through :term:`TUNE_FEATURES`. For example, the
``meta/conf/machine/include/x86/arch-x86.inc`` file defines the flags
for the x86 architecture as follows::
TUNE_LDARGS += "${@bb.utils.contains("TUNE_FEATURES", "mx32", "-m elf32_x86_64", "", d)}"
.. note::
Board Support Packages (BSPs) select the tune. The selected tune,
in turn, affects the tune variables themselves (i.e. the tune can
supply its own set of flags).
:term:`TUNE_PKGARCH`
The package architecture understood by the packaging system to define
the architecture, ABI, and tuning of output packages. The specific
tune is defined using the "_tune" override as follows::
TUNE_PKGARCH:tune-tune = "tune"
These tune-specific package architectures are defined in the machine
include files. Here is an example of the "core2-32" tuning as used in
the ``meta/conf/machine/include/x86/tune-core2.inc`` file::
TUNE_PKGARCH:tune-core2-32 = "core2-32"
:term:`TUNECONFLICTS[feature]`
Specifies CPU or Application Binary Interface (ABI) tuning features
that conflict with feature.
Known tuning conflicts are specified in the machine include files in
the :term:`Source Directory`. Here is an example from
the ``meta/conf/machine/include/mips/arch-mips.inc`` include file
that lists the "o32" and "n64" features as conflicting with the "n32"
feature::
TUNECONFLICTS[n32] = "o32 n64"
:term:`TUNEVALID[feature]`
Specifies a valid CPU or Application Binary Interface (ABI) tuning
feature. The specified feature is stored as a flag. Valid features
are specified in the machine include files (e.g.
``meta/conf/machine/include/arm/arch-arm.inc``). Here is an example
from that file::
TUNEVALID[bigendian] = "Enable big-endian mode."
See the machine include files in the :term:`Source Directory`
for these features.
:term:`UBOOT_CONFIG`
Configures the :term:`UBOOT_MACHINE` and can
also define :term:`IMAGE_FSTYPES` for individual
cases.
Following is an example from the ``meta-fsl-arm`` layer. ::
UBOOT_CONFIG ??= "sd"
UBOOT_CONFIG[sd] = "mx6qsabreauto_config,sdcard"
UBOOT_CONFIG[eimnor] = "mx6qsabreauto_eimnor_config"
UBOOT_CONFIG[nand] = "mx6qsabreauto_nand_config,ubifs"
UBOOT_CONFIG[spinor] = "mx6qsabreauto_spinor_config"
In this example, "sd" is selected as the configuration of the possible four for the
:term:`UBOOT_MACHINE`. The "sd" configuration defines
"mx6qsabreauto_config" as the value for :term:`UBOOT_MACHINE`, while the
"sdcard" specifies the :term:`IMAGE_FSTYPES` to use for the U-Boot image.
For more information on how the :term:`UBOOT_CONFIG` is handled, see the
:ref:`ref-classes-uboot-config` class.
:term:`UBOOT_DTB_LOADADDRESS`
Specifies the load address for the dtb image used by U-Boot. During FIT
image creation, the :term:`UBOOT_DTB_LOADADDRESS` variable is used in
:ref:`ref-classes-kernel-fitimage` class to specify the load address to be
used in creating the dtb sections of Image Tree Source for the FIT image.
:term:`UBOOT_DTBO_LOADADDRESS`
Specifies the load address for the dtbo image used by U-Boot. During FIT
image creation, the :term:`UBOOT_DTBO_LOADADDRESS` variable is used in
:ref:`ref-classes-kernel-fitimage` class to specify the load address to be
used in creating the dtbo sections of Image Tree Source for the FIT image.
:term:`UBOOT_ENTRYPOINT`
Specifies the entry point for the U-Boot image. During U-Boot image
creation, the :term:`UBOOT_ENTRYPOINT` variable is passed as a
command-line parameter to the ``uboot-mkimage`` utility.
:term:`UBOOT_LOADADDRESS`
Specifies the load address for the U-Boot image. During U-Boot image
creation, the :term:`UBOOT_LOADADDRESS` variable is passed as a
command-line parameter to the ``uboot-mkimage`` utility.
:term:`UBOOT_LOCALVERSION`
Appends a string to the name of the local version of the U-Boot
image. For example, assuming the version of the U-Boot image built
was "2013.10", the full version string reported by U-Boot would be
"2013.10-yocto" given the following statement::
UBOOT_LOCALVERSION = "-yocto"
:term:`UBOOT_MACHINE`
Specifies the value passed on the ``make`` command line when building
a U-Boot image. The value indicates the target platform
configuration. You typically set this variable from the machine
configuration file (i.e. ``conf/machine/machine_name.conf``).
Please see the "Selection of Processor Architecture and Board Type"
section in the U-Boot README for valid values for this variable.
:term:`UBOOT_MAKE_TARGET`
Specifies the target called in the ``Makefile``. The default target
is "all".
:term:`UBOOT_MKIMAGE`
Specifies the name of the mkimage command as used by the
:ref:`ref-classes-kernel-fitimage` class to assemble
the FIT image. This can be used to substitute an alternative command, wrapper
script or function if desired. The default is "uboot-mkimage".
:term:`UBOOT_MKIMAGE_DTCOPTS`
Options for the device tree compiler passed to mkimage '-D' feature while
creating FIT image in :ref:`ref-classes-kernel-fitimage` class. If
:term:`UBOOT_MKIMAGE_DTCOPTS` is not set then
:ref:`ref-classes-kernel-fitimage` will not pass the ``-D`` option to
mkimage.
:term:`UBOOT_MKIMAGE_KERNEL_TYPE`
Specifies the type argument for the kernel as passed to ``uboot-mkimage``.
The default value is "kernel".
:term:`UBOOT_MKIMAGE_SIGN`
Specifies the name of the mkimage command as used by the
:ref:`ref-classes-kernel-fitimage` class to sign
the FIT image after it has been assembled (if enabled). This can be used
to substitute an alternative command, wrapper script or function if
desired. The default is "${:term:`UBOOT_MKIMAGE`}".
:term:`UBOOT_MKIMAGE_SIGN_ARGS`
Optionally specifies additional arguments for the
:ref:`ref-classes-kernel-fitimage` class to pass to the
mkimage command when signing the FIT image.
:term:`UBOOT_RD_ENTRYPOINT`
Specifies the entrypoint for the RAM disk image. During FIT image
creation, the :term:`UBOOT_RD_ENTRYPOINT` variable is used in
:ref:`ref-classes-kernel-fitimage` class to specify the entrypoint to be
used in creating the Image Tree Source for the FIT image.
:term:`UBOOT_RD_LOADADDRESS`
Specifies the load address for the RAM disk image. During FIT image
creation, the :term:`UBOOT_RD_LOADADDRESS` variable is used in
:ref:`ref-classes-kernel-fitimage` class to specify the load address to
be used in creating the Image Tree Source for the FIT image.
:term:`UBOOT_SIGN_ENABLE`
Enable signing of FIT image. The default value is "0".
:term:`UBOOT_SIGN_KEYDIR`
Location of the directory containing the RSA key and
certificate used for signing FIT image.
:term:`UBOOT_SIGN_KEYNAME`
The name of keys used for signing U-Boot FIT image stored in
:term:`UBOOT_SIGN_KEYDIR` directory. For e.g. dev.key key and dev.crt
certificate stored in :term:`UBOOT_SIGN_KEYDIR` directory will have
:term:`UBOOT_SIGN_KEYNAME` set to "dev".
:term:`UBOOT_SUFFIX`
Points to the generated U-Boot extension. For example, ``u-boot.sb``
has a ``.sb`` extension.
The default U-Boot extension is ``.bin``
:term:`UBOOT_TARGET`
Specifies the target used for building U-Boot. The target is passed
directly as part of the "make" command (e.g. SPL and AIS). If you do
not specifically set this variable, the OpenEmbedded build process
passes and uses "all" for the target during the U-Boot building
process.
:term:`UNKNOWN_CONFIGURE_OPT_IGNORE`
Specifies a list of options that, if reported by the configure script
as being invalid, should not generate a warning during the
:ref:`ref-tasks-configure` task. Normally, invalid
configure options are simply not passed to the configure script (e.g.
should be removed from :term:`EXTRA_OECONF` or
:term:`PACKAGECONFIG_CONFARGS`).
However, there are common options that are passed to all
configure scripts at a class level, but might not be valid for some
configure scripts. Therefore warnings about these options are useless.
For these cases, the options are added to :term:`UNKNOWN_CONFIGURE_OPT_IGNORE`.
The configure arguments check that uses
:term:`UNKNOWN_CONFIGURE_OPT_IGNORE` is part of the
:ref:`ref-classes-insane` class and is only enabled if the
recipe inherits the :ref:`ref-classes-autotools` class.
:term:`UPDATERCPN`
For recipes inheriting the
:ref:`ref-classes-update-rc.d` class, :term:`UPDATERCPN`
specifies the package that contains the initscript that is enabled.
The default value is "${PN}". Given that almost all recipes that
install initscripts package them in the main package for the recipe,
you rarely need to set this variable in individual recipes.
:term:`UPSTREAM_CHECK_COMMITS`
You can perform a per-recipe check for what the latest upstream
source code version is by calling ``devtool latest-version recipe``. If
the recipe source code is provided from Git repositories, but
releases are not identified by Git tags, set :term:`UPSTREAM_CHECK_COMMITS`
to ``1`` in the recipe, and the OpenEmbedded build system
will compare the latest commit with the one currently specified
by the recipe (:term:`SRCREV`)::
UPSTREAM_CHECK_COMMITS = "1"
:term:`UPSTREAM_CHECK_GITTAGREGEX`
You can perform a per-recipe check for what the latest upstream
source code version is by calling ``devtool latest-version recipe``. If
the recipe source code is provided from Git repositories, the
OpenEmbedded build system determines the latest upstream version by
picking the latest tag from the list of all repository tags.
You can use the :term:`UPSTREAM_CHECK_GITTAGREGEX` variable to provide a
regular expression to filter only the relevant tags should the
default filter not work correctly::
UPSTREAM_CHECK_GITTAGREGEX = "git_tag_regex"
:term:`UPSTREAM_CHECK_REGEX`
Use the :term:`UPSTREAM_CHECK_REGEX` variable to specify a different
regular expression instead of the default one when the package
checking system is parsing the page found using
:term:`UPSTREAM_CHECK_URI`::
UPSTREAM_CHECK_REGEX = "package_regex"
:term:`UPSTREAM_CHECK_URI`
You can perform a per-recipe check for what the latest upstream
source code version is by calling ``devtool latest-version recipe``. If
the source code is provided from tarballs, the latest version is
determined by fetching the directory listing where the tarball is and
attempting to find a later tarball. When this approach does not work,
you can use :term:`UPSTREAM_CHECK_URI` to provide a different URI that
contains the link to the latest tarball::
UPSTREAM_CHECK_URI = "recipe_url"
:term:`UPSTREAM_VERSION_UNKNOWN`
You can perform a per-recipe check for what the latest upstream
source code version is by calling ``devtool latest-version recipe``.
If no combination of the :term:`UPSTREAM_CHECK_URI`, :term:`UPSTREAM_CHECK_REGEX`,
:term:`UPSTREAM_CHECK_GITTAGREGEX` and :term:`UPSTREAM_CHECK_COMMITS` variables in
the recipe allows to determine what the latest upstream version is,
you can set :term:`UPSTREAM_VERSION_UNKNOWN` to ``1`` in the recipe
to acknowledge that the check cannot be performed::
UPSTREAM_VERSION_UNKNOWN = "1"
:term:`USE_DEVFS`
Determines if ``devtmpfs`` is used for ``/dev`` population. The
default value used for :term:`USE_DEVFS` is "1" when no value is
specifically set. Typically, you would set :term:`USE_DEVFS` to "0" for a
statically populated ``/dev`` directory.
See the ":ref:`dev-manual/device-manager:selecting a device manager`" section in
the Yocto Project Development Tasks Manual for information on how to
use this variable.
:term:`USE_VT`
When using
:ref:`SysVinit <dev-manual/new-recipe:enabling system services>`,
determines whether or not to run a
`getty <https://en.wikipedia.org/wiki/Getty_%28Unix%29>`__ on any
virtual terminals in order to enable logging in through those
terminals.
The default value used for :term:`USE_VT` is "1" when no default value is
specifically set. Typically, you would set :term:`USE_VT` to "0" in the
machine configuration file for machines that do not have a graphical
display attached and therefore do not need virtual terminal
functionality.
:term:`USER_CLASSES`
A list of classes to globally inherit. These classes are used by the
OpenEmbedded build system to enable extra features.
Classes inherited using :term:`USER_CLASSES` must be located in the
``classes-global/`` or ``classes/`` subdirectories.
The default list is set in your ``local.conf`` file::
USER_CLASSES ?= "buildstats"
For more information, see
``meta-poky/conf/templates/default/local.conf.sample`` in the
:term:`Source Directory`.
:term:`USERADD_ERROR_DYNAMIC`
If set to ``error``, forces the OpenEmbedded build system to produce
an error if the user identification (``uid``) and group
identification (``gid``) values are not defined in any of the files
listed in :term:`USERADD_UID_TABLES` and
:term:`USERADD_GID_TABLES`. If set to
``warn``, a warning will be issued instead.
The default behavior for the build system is to dynamically apply
``uid`` and ``gid`` values. Consequently, the
:term:`USERADD_ERROR_DYNAMIC` variable is by default not set. If you plan
on using statically assigned ``gid`` and ``uid`` values, you should
set the :term:`USERADD_ERROR_DYNAMIC` variable in your ``local.conf``
file as follows::
USERADD_ERROR_DYNAMIC = "error"
Overriding the
default behavior implies you are going to also take steps to set
static ``uid`` and ``gid`` values through use of the
:term:`USERADDEXTENSION`,
:term:`USERADD_UID_TABLES`, and
:term:`USERADD_GID_TABLES` variables.
.. note::
There is a difference in behavior between setting
:term:`USERADD_ERROR_DYNAMIC` to ``error`` and setting it to ``warn``.
When it is set to ``warn``, the build system will report a warning for
every undefined ``uid`` and ``gid`` in any recipe. But when it is set
to ``error``, it will only report errors for recipes that are actually
built.
This saves you from having to add static IDs for recipes that you
know will never be built.
:term:`USERADD_GID_TABLES`
Specifies a password file to use for obtaining static group
identification (``gid``) values when the OpenEmbedded build system
adds a group to the system during package installation.
When applying static group identification (``gid``) values, the
OpenEmbedded build system looks in :term:`BBPATH` for a
``files/group`` file and then applies those ``uid`` values. Set the
variable as follows in your ``local.conf`` file::
USERADD_GID_TABLES = "files/group"
.. note::
Setting the :term:`USERADDEXTENSION` variable to "useradd-staticids"
causes the build system to use static ``gid`` values.
:term:`USERADD_PACKAGES`
When inheriting the :ref:`ref-classes-useradd` class,
this variable specifies the individual packages within the recipe
that require users and/or groups to be added.
You must set this variable if the recipe inherits the class. For
example, the following enables adding a user for the main package in
a recipe::
USERADD_PACKAGES = "${PN}"
.. note::
It follows that if you are going to use the :term:`USERADD_PACKAGES`
variable, you need to set one or more of the :term:`USERADD_PARAM`,
:term:`GROUPADD_PARAM`, or :term:`GROUPMEMS_PARAM` variables.
:term:`USERADD_PARAM`
When inheriting the :ref:`ref-classes-useradd` class,
this variable specifies for a package what parameters should pass to
the ``useradd`` command if you add a user to the system when the
package is installed.
Here is an example from the ``dbus`` recipe::
USERADD_PARAM:${PN} = "--system --home ${localstatedir}/lib/dbus \
--no-create-home --shell /bin/false \
--user-group messagebus"
For information on the
standard Linux shell command ``useradd``, see
https://linux.die.net/man/8/useradd.
:term:`USERADD_UID_TABLES`
Specifies a password file to use for obtaining static user
identification (``uid``) values when the OpenEmbedded build system
adds a user to the system during package installation.
When applying static user identification (``uid``) values, the
OpenEmbedded build system looks in :term:`BBPATH` for a
``files/passwd`` file and then applies those ``uid`` values. Set the
variable as follows in your ``local.conf`` file::
USERADD_UID_TABLES = "files/passwd"
.. note::
Setting the :term:`USERADDEXTENSION` variable to "useradd-staticids"
causes the build system to use static ``uid`` values.
:term:`USERADDEXTENSION`
When set to "useradd-staticids", causes the OpenEmbedded build system
to base all user and group additions on a static ``passwd`` and
``group`` files found in :term:`BBPATH`.
To use static user identification (``uid``) and group identification
(``gid``) values, set the variable as follows in your ``local.conf``
file: USERADDEXTENSION = "useradd-staticids"
.. note::
Setting this variable to use static ``uid`` and ``gid``
values causes the OpenEmbedded build system to employ the
:ref:`ref-classes-useradd` class.
If you use static ``uid`` and ``gid`` information, you must also
specify the ``files/passwd`` and ``files/group`` files by setting the
:term:`USERADD_UID_TABLES` and
:term:`USERADD_GID_TABLES` variables.
Additionally, you should also set the
:term:`USERADD_ERROR_DYNAMIC` variable.
:term:`VOLATILE_LOG_DIR`
Specifies the persistence of the target's ``/var/log`` directory,
which is used to house postinstall target log files.
By default, :term:`VOLATILE_LOG_DIR` is set to "yes", which means the
file is not persistent. You can override this setting by setting the
variable to "no" to make the log directory persistent.
:term:`WARN_QA`
Specifies the quality assurance checks whose failures are reported as
warnings by the OpenEmbedded build system. You set this variable in
your distribution configuration file. For a list of the checks you
can control with this variable, see the
":ref:`ref-classes-insane`" section.
:term:`WATCHDOG_TIMEOUT`
Specifies the timeout in seconds used by the ``watchdog`` recipe and
also by ``systemd`` during reboot. The default is 60 seconds.
:term:`WIRELESS_DAEMON`
For ``connman`` and ``packagegroup-base``, specifies the wireless
daemon to use. The default is "wpa-supplicant" (note that the value
uses a dash and not an underscore).
:term:`WKS_FILE`
Specifies the location of the Wic kickstart file that is used by the
OpenEmbedded build system to create a partitioned image
(``image.wic``). For information on how to create a partitioned
image, see the
":ref:`dev-manual/wic:creating partitioned images using wic`"
section in the Yocto Project Development Tasks Manual. For details on
the kickstart file format, see the ":doc:`/ref-manual/kickstart`" Chapter.
:term:`WKS_FILE_DEPENDS`
When placed in the recipe that builds your image, this variable lists
build-time dependencies. The :term:`WKS_FILE_DEPENDS` variable is only
applicable when Wic images are active (i.e. when
:term:`IMAGE_FSTYPES` contains entries related
to Wic). If your recipe does not create Wic images, the variable has
no effect.
The :term:`WKS_FILE_DEPENDS` variable is similar to the
:term:`DEPENDS` variable. When you use the variable in
your recipe that builds the Wic image, dependencies you list in the
:term:`WKS_FILE_DEPENDS` variable are added to the :term:`DEPENDS` variable.
With the :term:`WKS_FILE_DEPENDS` variable, you have the possibility to
specify a list of additional dependencies (e.g. native tools,
bootloaders, and so forth), that are required to build Wic images.
Following is an example::
WKS_FILE_DEPENDS = "some-native-tool"
In the
previous example, some-native-tool would be replaced with an actual
native tool on which the build would depend.
:term:`WKS_FILES`
Specifies a list of candidate Wic kickstart files to be used by the
OpenEmbedded build system to create a partitioned image. Only the
first one that is found, from left to right, will be used.
This is only useful when there are multiple ``.wks`` files that can be
used to produce an image. A typical case is when multiple layers are
used for different hardware platforms, each supplying a different
``.wks`` file. In this case, you specify all possible ones through
:term:`WKS_FILES`.
If only one ``.wks`` file is used, set :term:`WKS_FILE` instead.
:term:`WORKDIR`
The pathname of the work directory in which the OpenEmbedded build
system builds a recipe. This directory is located within the
:term:`TMPDIR` directory structure and is specific to
the recipe being built and the system for which it is being built.
The :term:`WORKDIR` directory is defined as follows::
${TMPDIR}/work/${MULTIMACH_TARGET_SYS}/${PN}/${EXTENDPE}${PV}-${PR}
The actual directory depends on several things:
- :term:`TMPDIR`: The top-level build output directory
- :term:`MULTIMACH_TARGET_SYS`: The target system identifier
- :term:`PN`: The recipe name
- :term:`EXTENDPE`: The epoch --- if :term:`PE` is not specified, which
is usually the case for most recipes, then :term:`EXTENDPE` is blank.
- :term:`PV`: The recipe version
- :term:`PR`: The recipe revision
As an example, assume a Source Directory top-level folder name
``poky``, a default :term:`Build Directory` at ``poky/build``, and a
``qemux86-poky-linux`` machine target system. Furthermore, suppose
your recipe is named ``foo_1.3.0-r0.bb``. In this case, the work
directory the build system uses to build the package would be as
follows::
poky/build/tmp/work/qemux86-poky-linux/foo/1.3.0-r0
:term:`XSERVER`
Specifies the packages that should be installed to provide an X
server and drivers for the current machine, assuming your image
directly includes ``packagegroup-core-x11-xserver`` or, perhaps
indirectly, includes "x11-base" in
:term:`IMAGE_FEATURES`.
The default value of :term:`XSERVER`, if not specified in the machine
configuration, is "xserver-xorg xf86-video-fbdev xf86-input-evdev".
:term:`XZ_THREADS`
Specifies the number of parallel threads that should be used when
using xz compression.
By default this scales with core count, but is never set less than 2
to ensure that multi-threaded mode is always used so that the output
file contents are deterministic. Builds will work with a value of 1
but the output will differ compared to the output from the compression
generated when more than one thread is used.
On systems where many tasks run in parallel, setting a limit to this
can be helpful in controlling system resource usage.
:term:`XZ_MEMLIMIT`
Specifies the maximum memory the xz compression should use as a percentage
of system memory. If unconstrained the xz compressor can use large amounts of
memory and become problematic with parallelism elsewhere in the build.
"50%" has been found to be a good value.
:term:`ZSTD_THREADS`
Specifies the number of parallel threads that should be used when
using ZStandard compression.
By default this scales with core count, but is never set less than 2
to ensure that multi-threaded mode is always used so that the output
file contents are deterministic. Builds will work with a value of 1
but the output will differ compared to the output from the compression
generated when more than one thread is used.
On systems where many tasks run in parallel, setting a limit to this
can be helpful in controlling system resource usage.