Revert "poky: subtree update:b23aa6b753..ad30a6d470"
This reverts commit af5e4ef732faedf66c6dc1756432e9de2ac72988.
This commit introduced openbmc/openbmc#3720 and no solution has been
forthcoming. Revert until we can get to the bottom of this.
Change-Id: I2fb0d81eb26cf3dadb2f2abdd1a1bb7a95eaf03c
diff --git a/poky/documentation/ref-manual/ref-structure.xml b/poky/documentation/ref-manual/ref-structure.xml
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+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='ref-structure'>
+
+<title>Source Directory Structure</title>
+
+<para>
+ The <link linkend='source-directory'>Source Directory</link>
+ consists of numerous files, directories and subdirectories;
+ understanding their locations and contents is key to using the
+ Yocto Project effectively.
+ This chapter describes the Source Directory and gives information about
+ those files and directories.
+</para>
+
+<para>
+ For information on how to establish a local Source Directory on your
+ development system, see the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#locating-yocto-project-source-files'>Locating Yocto Project Source Files</ulink>"
+ section in the Yocto Project Development Tasks Manual.
+</para>
+
+ <note>
+ The OpenEmbedded build system does not support file or directory names that
+ contain spaces.
+ Be sure that the Source Directory you use does not contain these types
+ of names.
+ </note>
+
+<section id='structure-core'>
+ <title>Top-Level Core Components</title>
+
+ <para>
+ This section describes the top-level components of the
+ <link linkend='source-directory'>Source Directory</link>.
+ </para>
+
+ <section id='structure-core-bitbake'>
+ <title><filename>bitbake/</filename></title>
+
+ <para>
+ This directory includes a copy of BitBake for ease of use.
+ The copy usually matches the current stable BitBake release from
+ the BitBake project.
+ BitBake, a
+ <link linkend='metadata'>Metadata</link>
+ interpreter, reads the Yocto Project Metadata and runs the tasks
+ defined by that data.
+ Failures are usually caused by errors in your Metadata and not from BitBake itself;
+ consequently, most users do not need to worry about BitBake.
+ </para>
+
+ <para>
+ When you run the <filename>bitbake</filename> command, the
+ main BitBake executable (which resides in the
+ <filename>bitbake/bin/</filename> directory) starts.
+ Sourcing the environment setup script (i.e.
+ <link linkend="structure-core-script"><filename>&OE_INIT_FILE;</filename></link>)
+ places the <filename>scripts/</filename> and
+ <filename>bitbake/bin/</filename> directories (in that order) into
+ the shell's <filename>PATH</filename> environment variable.
+ </para>
+
+ <para>
+ For more information on BitBake, see the
+ <ulink url='&YOCTO_DOCS_BB_URL;'>BitBake User Manual</ulink>.
+ </para>
+ </section>
+
+ <section id='structure-core-build'>
+ <title><filename>build/</filename></title>
+
+ <para>
+ This directory contains user configuration files and the output
+ generated by the OpenEmbedded build system in its standard configuration where
+ the source tree is combined with the output.
+ The
+ <link linkend='build-directory'>Build Directory</link>
+ is created initially when you <filename>source</filename>
+ the OpenEmbedded build environment setup script
+ (i.e.
+ <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>).
+ </para>
+
+ <para>
+ It is also possible to place output and configuration
+ files in a directory separate from the
+ <link linkend='source-directory'>Source Directory</link>
+ by providing a directory name when you <filename>source</filename>
+ the setup script.
+ For information on separating output from your local
+ Source Directory files (commonly described as an "out of tree" build), see the
+ "<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>"
+ section.
+ </para>
+ </section>
+
+ <section id='handbook'>
+ <title><filename>documentation/</filename></title>
+
+ <para>
+ This directory holds the source for the Yocto Project documentation
+ as well as templates and tools that allow you to generate PDF and HTML
+ versions of the manuals.
+ Each manual is contained in its own sub-folder;
+ for example, the files for this reference manual reside in
+ the <filename>ref-manual/</filename> directory.
+ </para>
+ </section>
+
+ <section id='structure-core-meta'>
+ <title><filename>meta/</filename></title>
+
+ <para>
+ This directory contains the minimal, underlying OpenEmbedded-Core metadata.
+ The directory holds recipes, common classes, and machine
+ configuration for strictly emulated targets (<filename>qemux86</filename>,
+ <filename>qemuarm</filename>, and so forth.)
+ </para>
+ </section>
+
+ <section id='structure-core-meta-poky'>
+ <title><filename>meta-poky/</filename></title>
+
+ <para>
+ Designed above the <filename>meta/</filename> content, this directory
+ adds just enough metadata to define the Poky reference distribution.
+ </para>
+ </section>
+
+ <section id='structure-core-meta-yocto-bsp'>
+ <title><filename>meta-yocto-bsp/</filename></title>
+
+ <para>
+ This directory contains the Yocto Project reference
+ hardware Board Support Packages (BSPs).
+ For more information on BSPs, see the
+ <ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support Package (BSP) Developer's Guide</ulink>.
+ </para>
+ </section>
+
+ <section id='structure-meta-selftest'>
+ <title><filename>meta-selftest/</filename></title>
+
+ <para>
+ This directory adds additional recipes and append files
+ used by the OpenEmbedded selftests to verify the behavior
+ of the build system.
+ You do not have to add this layer to your
+ <filename>bblayers.conf</filename> file unless you want to run the
+ selftests.
+ </para>
+ </section>
+
+ <section id='structure-meta-skeleton'>
+ <title><filename>meta-skeleton/</filename></title>
+
+ <para>
+ This directory contains template recipes for BSP and kernel development.
+ </para>
+ </section>
+
+ <section id='structure-core-scripts'>
+ <title><filename>scripts/</filename></title>
+
+ <para>
+ This directory contains various integration scripts that implement
+ extra functionality in the Yocto Project environment (e.g. QEMU scripts).
+ The <link linkend="structure-core-script"><filename>&OE_INIT_FILE;</filename></link>
+ script prepends this directory to the shell's
+ <filename>PATH</filename> environment variable.
+ </para>
+
+ <para>
+ The <filename>scripts</filename> directory has useful scripts that assist in contributing
+ back to the Yocto Project, such as <filename>create-pull-request</filename> and
+ <filename>send-pull-request</filename>.
+ </para>
+ </section>
+
+ <section id='structure-core-script'>
+ <title><filename>&OE_INIT_FILE;</filename></title>
+
+ <para>
+ This script sets up the OpenEmbedded build environment.
+ Running this script with the <filename>source</filename> command in
+ a shell makes changes to <filename>PATH</filename> and sets other
+ core BitBake variables based on the current working directory.
+ You need to run an environment setup script before running BitBake
+ commands.
+ The script uses other scripts within the
+ <filename>scripts</filename> directory to do the bulk of the work.
+ </para>
+
+ <para>
+ When you run this script, your Yocto Project environment is set
+ up, a
+ <link linkend='build-directory'>Build Directory</link>
+ is created, your working directory becomes the Build Directory,
+ and you are presented with some simple suggestions as to what to do
+ next, including a list of some possible targets to build.
+ Here is an example:
+ <literallayout class='monospaced'>
+ $ source oe-init-build-env
+
+ ### Shell environment set up for builds. ###
+
+ You can now run 'bitbake <target>'
+
+ Common targets are:
+ core-image-minimal
+ core-image-sato
+ meta-toolchain
+ meta-ide-support
+
+ You can also run generated qemu images with a command like 'runqemu qemux86-64'
+ </literallayout>
+ The default output of the <filename>oe-init-build-env</filename> script
+ is from the <filename>conf-notes.txt</filename> file, which is found in the
+ <filename>meta-poky</filename> directory within the
+ <link linkend='source-directory'>Source Directory</link>.
+ If you design a custom distribution, you can include your own version
+ of this configuration file to mention the targets defined by your
+ distribution.
+ See the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-a-custom-template-configuration-directory'>Creating a Custom Template Configuration Directory</ulink>"
+ section in the Yocto Project Development Tasks Manual for more
+ information.
+ </para>
+
+ <para>
+ By default, running this script without a Build Directory
+ argument creates the <filename>build/</filename> directory
+ in your current working directory.
+ If you provide a Build Directory argument when you
+ <filename>source</filename> the script, you direct the OpenEmbedded
+ build system to create a Build Directory of your choice.
+ For example, the following command creates a Build Directory named
+ <filename>mybuilds/</filename> that is outside of the
+ <link linkend='source-directory'>Source Directory</link>:
+ <literallayout class='monospaced'>
+ $ source &OE_INIT_FILE; ~/mybuilds
+ </literallayout>
+ The OpenEmbedded build system uses the template configuration
+ files, which are found by default in the
+ <filename>meta-poky/conf/</filename> directory in the
+ Source Directory.
+ See the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-a-custom-template-configuration-directory'>Creating a Custom Template Configuration Directory</ulink>"
+ section in the Yocto Project Development Tasks Manual for more
+ information.
+ <note>
+ The OpenEmbedded build system does not support file or directory names that
+ contain spaces.
+ If you attempt to run the <filename>&OE_INIT_FILE;</filename> script
+ from a Source Directory that contains spaces in either the filenames
+ or directory names, the script returns an error indicating no such
+ file or directory.
+ Be sure to use a Source Directory free of names containing spaces.
+ </note>
+ </para>
+ </section>
+
+ <section id='structure-basic-top-level'>
+ <title><filename>LICENSE, README, and README.hardware</filename></title>
+
+ <para>
+ These files are standard top-level files.
+ </para>
+ </section>
+</section>
+
+<section id='structure-build'>
+ <title>The Build Directory - <filename>build/</filename></title>
+
+ <para>
+ The OpenEmbedded build system creates the
+ <link linkend='build-directory'>Build Directory</link>
+ when you run the build environment setup script
+ <link
+linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>.
+ If you do not give the Build Directory a specific name when you run
+ the setup script, the name defaults to <filename>build/</filename>.
+ </para>
+
+ <para>
+ For subsequent parsing and processing, the name of the Build
+ directory is available via the
+ <link linkend='var-TOPDIR'><filename>TOPDIR</filename></link> variable.
+ </para>
+
+ <section id='structure-build-buildhistory'>
+ <title><filename>build/buildhistory/</filename></title>
+
+ <para>
+ The OpenEmbedded build system creates this directory when you
+ enable build history via the <filename>buildhistory</filename> class file.
+ The directory organizes build information into image, packages, and
+ SDK subdirectories.
+ For information on the build history feature, see the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-build-output-quality'>Maintaining Build Output Quality</ulink>"
+ section in the Yocto Project Development Tasks Manual.
+ </para>
+ </section>
+
+ <section id='structure-build-conf-local.conf'>
+ <title><filename>build/conf/local.conf</filename></title>
+
+ <para>
+ This configuration file contains all the local user configurations
+ for your build environment.
+ The <filename>local.conf</filename> file contains documentation on
+ the various configuration options.
+ Any variable set here overrides any variable set elsewhere within
+ the environment unless that variable is hard-coded within a file
+ (e.g. by using '=' instead of '?=').
+ Some variables are hard-coded for various reasons but such
+ variables are relatively rare.
+ </para>
+
+ <para>
+ At a minimum, you would normally edit this file to select the target
+ <filename><link linkend='var-MACHINE'>MACHINE</link></filename>,
+ which package types you wish to use
+ (<link linkend='var-PACKAGE_CLASSES'><filename>PACKAGE_CLASSES</filename></link>),
+ and the location from which you want to access downloaded files
+ (<filename><link linkend='var-DL_DIR'>DL_DIR</link></filename>).
+ </para>
+
+ <para>
+ If <filename>local.conf</filename> is not present when you
+ start the build, the OpenEmbedded build system creates it from
+ <filename>local.conf.sample</filename> when
+ you <filename>source</filename> the top-level build environment
+ setup script
+ <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>.
+ </para>
+
+ <para>
+ The source <filename>local.conf.sample</filename> file used
+ depends on the <filename>$TEMPLATECONF</filename> script variable,
+ which defaults to <filename>meta-poky/conf/</filename>
+ when you are building from the Yocto Project development
+ environment, and to <filename>meta/conf/</filename> when
+ you are building from the OpenEmbedded-Core environment.
+ Because the script variable points to the source of the
+ <filename>local.conf.sample</filename> file, this implies that
+ you can configure your build environment from any layer by setting
+ the variable in the top-level build environment setup script as
+ follows:
+ <literallayout class='monospaced'>
+ TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
+ </literallayout>
+ Once the build process gets the sample file, it uses
+ <filename>sed</filename> to substitute final
+ <filename>${</filename><link linkend='var-OEROOT'><filename>OEROOT</filename></link><filename>}</filename>
+ values for all <filename>##OEROOT##</filename> values.
+ <note>
+ You can see how the <filename>TEMPLATECONF</filename> variable
+ is used by looking at the
+ <filename>scripts/oe-setup-builddir</filename> script in the
+ <link linkend='source-directory'>Source Directory</link>.
+ You can find the Yocto Project version of the
+ <filename>local.conf.sample</filename> file in the
+ <filename>meta-poky/conf</filename> directory.
+ </note>
+ </para>
+ </section>
+
+ <section id='structure-build-conf-bblayers.conf'>
+ <title><filename>build/conf/bblayers.conf</filename></title>
+
+ <para>
+ This configuration file defines
+ <ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>layers</ulink>,
+ which are directory trees, traversed (or walked) by BitBake.
+ The <filename>bblayers.conf</filename> file uses the
+ <link linkend='var-BBLAYERS'><filename>BBLAYERS</filename></link>
+ variable to list the layers BitBake tries to find.
+ </para>
+
+ <para>
+ If <filename>bblayers.conf</filename> is not present when you
+ start the build, the OpenEmbedded build system creates it from
+ <filename>bblayers.conf.sample</filename> when
+ you <filename>source</filename> the top-level build environment
+ setup script (i.e.
+ <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>).
+ </para>
+
+ <para>
+ As with the <filename>local.conf</filename> file,
+ the source <filename>bblayers.conf.sample</filename> file used
+ depends on the <filename>$TEMPLATECONF</filename> script variable,
+ which defaults to <filename>meta-poky/conf/</filename>
+ when you are building from the Yocto Project development
+ environment, and to <filename>meta/conf/</filename> when
+ you are building from the OpenEmbedded-Core environment.
+ Because the script variable points to the source of the
+ <filename>bblayers.conf.sample</filename> file, this implies that
+ you can base your build from any layer by setting the variable in
+ the top-level build environment setup script as follows:
+ <literallayout class='monospaced'>
+ TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
+ </literallayout>
+ Once the build process gets the sample file, it uses
+ <filename>sed</filename> to substitute final
+ <filename>${</filename><link linkend='var-OEROOT'><filename>OEROOT</filename></link><filename>}</filename>
+ values for all <filename>##OEROOT##</filename> values.
+ <note>
+ You can see how the <filename>TEMPLATECONF</filename> variable
+ <filename>scripts/oe-setup-builddir</filename> script in the
+ <link linkend='source-directory'>Source Directory</link>.
+ You can find the Yocto Project version of the
+ <filename>bblayers.conf.sample</filename> file in the
+ <filename>meta-poky/conf/</filename> directory.
+ </note>
+ </para>
+ </section>
+
+ <section id='structure-build-conf-sanity_info'>
+ <title><filename>build/cache/sanity_info</filename></title>
+
+ <para>
+ This file indicates the state of the sanity checks and is created
+ during the build.
+ </para>
+ </section>
+
+ <section id='structure-build-downloads'>
+ <title><filename>build/downloads/</filename></title>
+
+ <para>
+ This directory contains downloaded upstream source tarballs.
+ You can reuse the directory for multiple builds or move
+ the directory to another location.
+ You can control the location of this directory through the
+ <filename><link linkend='var-DL_DIR'>DL_DIR</link></filename> variable.
+ </para>
+ </section>
+
+ <section id='structure-build-sstate-cache'>
+ <title><filename>build/sstate-cache/</filename></title>
+
+ <para>
+ This directory contains the shared state cache.
+ You can reuse the directory for multiple builds or move
+ the directory to another location.
+ You can control the location of this directory through the
+ <filename><link linkend='var-SSTATE_DIR'>SSTATE_DIR</link></filename> variable.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp'>
+ <title><filename>build/tmp/</filename></title>
+
+ <para>
+ The OpenEmbedded build system creates and uses this directory
+ for all the build system's output.
+ The
+ <link linkend='var-TMPDIR'><filename>TMPDIR</filename></link>
+ variable points to this directory.
+ </para>
+
+ <para>
+ BitBake creates this directory if it does not exist.
+ As a last resort, to clean up a build and start it from scratch
+ (other than the downloads), you can remove everything in the
+ <filename>tmp</filename> directory or get rid of the
+ directory completely.
+ If you do, you should also completely remove the
+ <filename>build/sstate-cache</filename> directory.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-buildstats'>
+ <title><filename>build/tmp/buildstats/</filename></title>
+
+ <para>
+ This directory stores the build statistics.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-cache'>
+ <title><filename>build/tmp/cache/</filename></title>
+
+ <para>
+ When BitBake parses the metadata (recipes and configuration files),
+ it caches the results in <filename>build/tmp/cache/</filename>
+ to speed up future builds.
+ The results are stored on a per-machine basis.
+ </para>
+
+ <para>
+ During subsequent builds, BitBake checks each recipe (together
+ with, for example, any files included or appended to it) to see
+ if they have been modified.
+ Changes can be detected, for example, through file modification
+ time (mtime) changes and hashing of file contents.
+ If no changes to the file are detected, then the parsed result
+ stored in the cache is reused.
+ If the file has changed, it is reparsed.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy'>
+ <title><filename>build/tmp/deploy/</filename></title>
+
+ <para>
+ This directory contains any "end result" output from the
+ OpenEmbedded build process.
+ The <link linkend='var-DEPLOY_DIR'><filename>DEPLOY_DIR</filename></link>
+ variable points to this directory.
+ For more detail on the contents of the <filename>deploy</filename>
+ directory, see the
+ "<ulink url='&YOCTO_DOCS_OM_URL;#images-dev-environment'>Images</ulink>"
+ and
+ "<ulink url='&YOCTO_DOCS_OM_URL;#sdk-dev-environment'>Application Development SDK</ulink>"
+ sections in the Yocto Project Overview and Concepts Manual.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-deb'>
+ <title><filename>build/tmp/deploy/deb/</filename></title>
+
+ <para>
+ This directory receives any <filename>.deb</filename> packages produced by
+ the build process.
+ The packages are sorted into feeds for different architecture types.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-rpm'>
+ <title><filename>build/tmp/deploy/rpm/</filename></title>
+
+ <para>
+ This directory receives any <filename>.rpm</filename> packages produced by
+ the build process.
+ The packages are sorted into feeds for different architecture types.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-ipk'>
+ <title><filename>build/tmp/deploy/ipk/</filename></title>
+
+ <para>
+ This directory receives <filename>.ipk</filename> packages produced by
+ the build process.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-licenses'>
+ <title><filename>build/tmp/deploy/licenses/</filename></title>
+
+ <para>
+ This directory receives package licensing information.
+ For example, the directory contains sub-directories for <filename>bash</filename>,
+ <filename>busybox</filename>, and <filename>glibc</filename> (among others) that in turn
+ contain appropriate <filename>COPYING</filename> license files with other licensing information.
+ For information on licensing, see the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-open-source-license-compliance-during-your-products-lifecycle'>Maintaining Open Source License Compliance During Your Product's Lifecycle</ulink>"
+ section in the Yocto Project Development Tasks Manual.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-images'>
+ <title><filename>build/tmp/deploy/images/</filename></title>
+
+ <para>
+ This directory is populated with the basic output objects of the
+ build (think of them as the "generated artifacts" of the build process),
+ including things like the boot loader image, kernel, root filesystem and more.
+ If you want to flash the resulting image from a build onto a device,
+ look here for the necessary components.
+ </para>
+
+ <para>
+ Be careful when deleting files in this directory.
+ You can safely delete old images from this directory (e.g.
+ <filename>core-image-*</filename>).
+ However, the kernel (<filename>*zImage*</filename>, <filename>*uImage*</filename>, etc.),
+ bootloader and other supplementary files might be deployed here prior to building an
+ image.
+ Because these files are not directly produced from the image, if you
+ delete them they will not be automatically re-created when you build the image again.
+ </para>
+
+ <para>
+ If you do accidentally delete files here, you will need to force them to be
+ re-created.
+ In order to do that, you will need to know the target that produced them.
+ For example, these commands rebuild and re-create the kernel files:
+ <literallayout class='monospaced'>
+ $ bitbake -c clean virtual/kernel
+ $ bitbake virtual/kernel
+ </literallayout>
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-sdk'>
+ <title><filename>build/tmp/deploy/sdk/</filename></title>
+
+ <para>
+ The OpenEmbedded build system creates this directory to hold
+ toolchain installer scripts which, when executed, install the
+ sysroot that matches your target hardware.
+ You can find out more about these installers in the
+ "<ulink url='&YOCTO_DOCS_SDK_URL;#sdk-building-an-sdk-installer'>Building an SDK Installer</ulink>"
+ section in the Yocto Project Application Development and the
+ Extensible Software Development Kit (eSDK) manual.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-sstate-control'>
+ <title><filename>build/tmp/sstate-control/</filename></title>
+
+ <para>
+ The OpenEmbedded build system uses this directory for the
+ shared state manifest files.
+ The shared state code uses these files to record the files
+ installed by each sstate task so that the files can be removed
+ when cleaning the recipe or when a newer version is about to
+ be installed.
+ The build system also uses the manifests to detect and produce
+ a warning when files from one task are overwriting those from
+ another.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-sysroots-components'>
+ <title><filename>build/tmp/sysroots-components/</filename></title>
+
+ <para>
+ This directory is the location of the sysroot contents that the
+ task
+ <link linkend='ref-tasks-prepare_recipe_sysroot'><filename>do_prepare_recipe_sysroot</filename></link>
+ links or copies into the recipe-specific sysroot for each
+ recipe listed in
+ <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>.
+ Population of this directory is handled through shared state, while
+ the path is specified by the
+ <link linkend='var-COMPONENTS_DIR'><filename>COMPONENTS_DIR</filename></link>
+ variable. Apart from a few unusual circumstances, handling of the
+ <filename>sysroots-components</filename> directory should be
+ automatic, and recipes should not directly reference
+ <filename>build/tmp/sysroots-components</filename>.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-sysroots'>
+ <title><filename>build/tmp/sysroots/</filename></title>
+
+ <para>
+ Previous versions of the OpenEmbedded build system used to
+ create a global shared sysroot per machine along with a native
+ sysroot.
+ Beginning with the &DISTRO; version of the Yocto Project,
+ sysroots exist in recipe-specific
+ <link linkend='var-WORKDIR'><filename>WORKDIR</filename></link>
+ directories.
+ Thus, the <filename>build/tmp/sysroots/</filename> directory
+ is unused.
+ <note>
+ The <filename>build/tmp/sysroots/</filename> directory
+ can still be populated using the
+ <filename>bitbake build-sysroots</filename> command and can
+ be used for compatibility in some cases.
+ However, in general it is not recommended to populate
+ this directory.
+ Individual recipe-specific sysroots should be used.
+ </note>
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-stamps'>
+ <title><filename>build/tmp/stamps/</filename></title>
+
+ <para>
+ This directory holds information that BitBake uses for
+ accounting purposes to track what tasks have run and when they
+ have run.
+ The directory is sub-divided by architecture, package name, and
+ version.
+ Following is an example:
+ <literallayout class='monospaced'>
+ stamps/all-poky-linux/distcc-config/1.0-r0.do_build-2fdd....2do
+ </literallayout>
+ Although the files in the directory are empty of data,
+ BitBake uses the filenames and timestamps for tracking purposes.
+ </para>
+
+ <para>
+ For information on how BitBake uses stamp files to determine if
+ a task should be rerun, see the
+ "<ulink url='&YOCTO_DOCS_OM_URL;#stamp-files-and-the-rerunning-of-tasks'>Stamp Files and the Rerunning of Tasks</ulink>"
+ section in the Yocto Project Overview and Concepts Manual.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-log'>
+ <title><filename>build/tmp/log/</filename></title>
+
+ <para>
+ This directory contains general logs that are not otherwise placed using the
+ package's <filename><link linkend='var-WORKDIR'>WORKDIR</link></filename>.
+ Examples of logs are the output from the
+ <filename>do_check_pkg</filename> or
+ <filename>do_distro_check</filename> tasks.
+ Running a build does not necessarily mean this directory is created.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-work'>
+ <title><filename>build/tmp/work/</filename></title>
+
+ <para>
+ This directory contains architecture-specific work sub-directories
+ for packages built by BitBake.
+ All tasks execute from the appropriate work directory.
+ For example, the source for a particular package is unpacked,
+ patched, configured and compiled all within its own work directory.
+ Within the work directory, organization is based on the package group
+ and version for which the source is being compiled
+ as defined by the
+ <link linkend='var-WORKDIR'><filename>WORKDIR</filename></link>.
+ </para>
+
+ <para>
+ It is worth considering the structure of a typical work directory.
+ As an example, consider <filename>linux-yocto-kernel-3.0</filename>
+ on the machine <filename>qemux86</filename>
+ built within the Yocto Project.
+ For this package, a work directory of
+ <filename>tmp/work/qemux86-poky-linux/linux-yocto/3.0+git1+<.....></filename>,
+ referred to as the <filename>WORKDIR</filename>, is created.
+ Within this directory, the source is unpacked to
+ <filename>linux-qemux86-standard-build</filename> and then patched by Quilt.
+ (See the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#using-a-quilt-workflow'>Using Quilt in Your Workflow</ulink>"
+ section in the Yocto Project Development Tasks Manual for more
+ information.)
+ Within the <filename>linux-qemux86-standard-build</filename> directory,
+ standard Quilt directories <filename>linux-3.0/patches</filename>
+ and <filename>linux-3.0/.pc</filename> are created,
+ and standard Quilt commands can be used.
+ </para>
+
+ <para>
+ There are other directories generated within <filename>WORKDIR</filename>.
+ The most important directory is <filename>WORKDIR/temp/</filename>,
+ which has log files for each task (<filename>log.do_*.pid</filename>)
+ and contains the scripts BitBake runs for each task
+ (<filename>run.do_*.pid</filename>).
+ The <filename>WORKDIR/image/</filename> directory is where "make
+ install" places its output that is then split into sub-packages
+ within <filename>WORKDIR/packages-split/</filename>.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-work-tunearch-recipename-version'>
+ <title><filename>build/tmp/work/<replaceable>tunearch</replaceable>/<replaceable>recipename</replaceable>/<replaceable>version</replaceable>/</filename></title>
+
+ <para>
+ The recipe work directory - <filename>${WORKDIR}</filename>.
+ </para>
+
+ <para>
+ As described earlier in the
+ "<link linkend='structure-build-tmp-sysroots'><filename>build/tmp/sysroots/</filename></link>"
+ section, beginning with the &DISTRO; release of the Yocto
+ Project, the OpenEmbedded build system builds each recipe in its
+ own work directory (i.e.
+ <link linkend='var-WORKDIR'><filename>WORKDIR</filename></link>).
+ The path to the work directory is constructed using the
+ architecture of the given build (e.g.
+ <link linkend='var-TUNE_PKGARCH'><filename>TUNE_PKGARCH</filename></link>,
+ <link linkend='var-MACHINE_ARCH'><filename>MACHINE_ARCH</filename></link>,
+ or "allarch"), the recipe name, and the version of the recipe (i.e.
+ <link linkend='var-PE'><filename>PE</filename></link><filename>:</filename><link linkend='var-PV'><filename>PV</filename></link><filename>-</filename><link linkend='var-PR'><filename>PR</filename></link>).
+ </para>
+
+ <para>
+ A number of key subdirectories exist within each recipe
+ work directory:
+ <itemizedlist>
+ <listitem><para>
+ <filename>${WORKDIR}/temp</filename>:
+ Contains the log files of each task executed for this
+ recipe, the "run" files for each executed task, which
+ contain the code run, and a
+ <filename>log.task_order</filename> file, which lists the
+ order in which tasks were executed.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/image</filename>:
+ Contains the output of the
+ <link linkend='ref-tasks-install'><filename>do_install</filename></link>
+ task, which corresponds to the
+ <filename>${</filename><link linkend='var-D'><filename>D</filename></link><filename>}</filename>
+ variable in that task.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/pseudo</filename>:
+ Contains the pseudo database and log for any tasks executed
+ under pseudo for the recipe.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/sysroot-destdir</filename>:
+ Contains the output of the
+ <link linkend='ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></link>
+ task.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/package</filename>:
+ Contains the output of the
+ <link linkend='ref-tasks-package'><filename>do_package</filename></link>
+ task before the output is split into individual packages.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/packages-split</filename>:
+ Contains the output of the <filename>do_package</filename>
+ task after the output has been split into individual
+ packages.
+ Subdirectories exist for each individual package created
+ by the recipe.
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/recipe-sysroot</filename>:
+ A directory populated with the target dependencies of the
+ recipe.
+ This directory looks like the target filesystem and
+ contains libraries that the recipe might need to link
+ against (e.g. the C library).
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/recipe-sysroot-native</filename>:
+ A directory populated with the native dependencies of the
+ recipe.
+ This directory contains the tools the recipe needs to build
+ (e.g. the compiler, Autoconf, libtool, and so forth).
+ </para></listitem>
+ <listitem><para>
+ <filename>${WORKDIR}/build</filename>:
+ This subdirectory applies only to recipes that support
+ builds where the source is separate from the
+ build artifacts.
+ The OpenEmbedded build system uses this directory as a
+ separate build directory (i.e.
+ <filename>${</filename><link linkend='var-B'><filename>B</filename></link><filename>}</filename>).
+ </para></listitem>
+ </itemizedlist>
+ </para>
+ </section>
+
+ <section id='structure-build-work-shared'>
+ <title><filename>build/tmp/work-shared/</filename></title>
+
+ <para>
+ For efficiency, the OpenEmbedded build system creates and uses
+ this directory to hold recipes that share a work directory with
+ other recipes.
+ In practice, this is only used for <filename>gcc</filename>
+ and its variants (e.g. <filename>gcc-cross</filename>,
+ <filename>libgcc</filename>, <filename>gcc-runtime</filename>,
+ and so forth).
+ </para>
+ </section>
+</section>
+
+<section id='structure-meta'>
+ <title>The Metadata - <filename>meta/</filename></title>
+
+ <para>
+ As mentioned previously,
+ <link linkend='metadata'>Metadata</link> is the core
+ of the Yocto Project.
+ Metadata has several important subdivisions:
+ </para>
+
+ <section id='structure-meta-classes'>
+ <title><filename>meta/classes/</filename></title>
+
+ <para>
+ This directory contains the <filename>*.bbclass</filename> files.
+ Class files are used to abstract common code so it can be reused by multiple
+ packages.
+ Every package inherits the <filename>base.bbclass</filename> file.
+ Examples of other important classes are <filename>autotools.bbclass</filename>, which
+ in theory allows any Autotool-enabled package to work with the Yocto Project with minimal effort.
+ Another example is <filename>kernel.bbclass</filename> that contains common code and functions
+ for working with the Linux kernel.
+ Functions like image generation or packaging also have their specific class files
+ such as <filename>image.bbclass</filename>, <filename>rootfs_*.bbclass</filename> and
+ <filename>package*.bbclass</filename>.
+ </para>
+
+ <para>
+ For reference information on classes, see the
+ "<link linkend='ref-classes'>Classes</link>" chapter.
+ </para>
+ </section>
+
+ <section id='structure-meta-conf'>
+ <title><filename>meta/conf/</filename></title>
+
+ <para>
+ This directory contains the core set of configuration files that start from
+ <filename>bitbake.conf</filename> and from which all other configuration
+ files are included.
+ See the include statements at the end of the
+ <filename>bitbake.conf</filename> file and you will note that even
+ <filename>local.conf</filename> is loaded from there.
+ While <filename>bitbake.conf</filename> sets up the defaults, you can often override
+ these by using the (<filename>local.conf</filename>) file, machine file or
+ the distribution configuration file.
+ </para>
+ </section>
+
+ <section id='structure-meta-conf-machine'>
+ <title><filename>meta/conf/machine/</filename></title>
+
+ <para>
+ This directory contains all the machine configuration files.
+ If you set <filename>MACHINE = "qemux86"</filename>,
+ the OpenEmbedded build system looks for a <filename>qemux86.conf</filename> file in this
+ directory.
+ The <filename>include</filename> directory contains various data common to multiple machines.
+ If you want to add support for a new machine to the Yocto Project, look in this directory.
+ </para>
+ </section>
+
+ <section id='structure-meta-conf-distro'>
+ <title><filename>meta/conf/distro/</filename></title>
+
+ <para>
+ The contents of this directory controls any distribution-specific
+ configurations.
+ For the Yocto Project, the <filename>defaultsetup.conf</filename> is the main file here.
+ This directory includes the versions and the
+ <filename>SRCDATE</filename> definitions for applications that are configured here.
+ An example of an alternative configuration might be <filename>poky-bleeding.conf</filename>.
+ Although this file mainly inherits its configuration from Poky.
+ </para>
+ </section>
+
+ <section id='structure-meta-conf-machine-sdk'>
+ <title><filename>meta/conf/machine-sdk/</filename></title>
+
+ <para>
+ The OpenEmbedded build system searches this directory for
+ configuration files that correspond to the value of
+ <link linkend='var-SDKMACHINE'><filename>SDKMACHINE</filename></link>.
+ By default, 32-bit and 64-bit x86 files ship with the Yocto
+ Project that support some SDK hosts.
+ However, it is possible to extend that support to other SDK hosts
+ by adding additional configuration files in this subdirectory
+ within another layer.
+ </para>
+ </section>
+
+ <section id='structure-meta-files'>
+ <title><filename>meta/files/</filename></title>
+
+ <para>
+ This directory contains common license files and several text files
+ used by the build system.
+ The text files contain minimal device information and
+ lists of files and directories with known permissions.
+ </para>
+ </section>
+
+ <section id='structure-meta-lib'>
+ <title><filename>meta/lib/</filename></title>
+
+ <para>
+ This directory contains OpenEmbedded Python library code
+ used during the build process.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-bsp'>
+ <title><filename>meta/recipes-bsp/</filename></title>
+
+ <para>
+ This directory contains anything linking to specific hardware or hardware
+ configuration information such as "u-boot" and "grub".
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-connectivity'>
+ <title><filename>meta/recipes-connectivity/</filename></title>
+
+ <para>
+ This directory contains libraries and applications related to communication with other devices.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-core'>
+ <title><filename>meta/recipes-core/</filename></title>
+
+ <para>
+ This directory contains what is needed to build a basic working Linux image
+ including commonly used dependencies.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-devtools'>
+ <title><filename>meta/recipes-devtools/</filename></title>
+
+ <para>
+ This directory contains tools that are primarily used by the build system.
+ The tools, however, can also be used on targets.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-extended'>
+ <title><filename>meta/recipes-extended/</filename></title>
+
+ <para>
+ This directory contains non-essential applications that add features compared to the
+ alternatives in core.
+ You might need this directory for full tool functionality or for Linux Standard Base (LSB)
+ compliance.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-gnome'>
+ <title><filename>meta/recipes-gnome/</filename></title>
+
+ <para>
+ This directory contains all things related to the GTK+ application framework.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-graphics'>
+ <title><filename>meta/recipes-graphics/</filename></title>
+
+ <para>
+ This directory contains X and other graphically related system libraries.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-kernel'>
+ <title><filename>meta/recipes-kernel/</filename></title>
+
+ <para>
+ This directory contains the kernel and generic applications and libraries that
+ have strong kernel dependencies.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-lsb4'>
+ <title><filename>meta/recipes-lsb4/</filename></title>
+
+ <para>
+ This directory contains recipes specifically added to support
+ the Linux Standard Base (LSB) version 4.x.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-multimedia'>
+ <title><filename>meta/recipes-multimedia/</filename></title>
+
+ <para>
+ This directory contains codecs and support utilities for audio, images and video.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-rt'>
+ <title><filename>meta/recipes-rt/</filename></title>
+
+ <para>
+ This directory contains package and image recipes for using and testing
+ the <filename>PREEMPT_RT</filename> kernel.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-sato'>
+ <title><filename>meta/recipes-sato/</filename></title>
+
+ <para>
+ This directory contains the Sato demo/reference UI/UX and its associated applications
+ and configuration data.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-support'>
+ <title><filename>meta/recipes-support/</filename></title>
+
+ <para>
+ This directory contains recipes used by other recipes, but that are
+ not directly included in images (i.e. dependencies of other
+ recipes).
+ </para>
+ </section>
+
+ <section id='structure-meta-site'>
+ <title><filename>meta/site/</filename></title>
+
+ <para>
+ This directory contains a list of cached results for various architectures.
+ Because certain "autoconf" test results cannot be determined when cross-compiling due to
+ the tests not able to run on a live system, the information in this directory is
+ passed to "autoconf" for the various architectures.
+ </para>
+ </section>
+
+ <section id='structure-meta-recipes-txt'>
+ <title><filename>meta/recipes.txt</filename></title>
+
+ <para>
+ This file is a description of the contents of <filename>recipes-*</filename>.
+ </para>
+ </section>
+</section>
+
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->