| <!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 |
| --> |