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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; ] >
+
+<chapter id='ref-structure'>
+
+<title>Source Directory Structure</title>
+
+<para>
+ The <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink> consists of several components.
+ Understanding them and knowing where they are located is key to using the Yocto Project well.
+ This chapter describes the Source Directory and gives information about the various
+ 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;#getting-setup'>Getting Set Up</ulink>"
+ section in the Yocto Project Development 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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ </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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink>
+ interpreter, reads the Yocto Project Metadata and runs the tasks
+ defined by that data.
+ Failures are usually from the 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 an environment setup script (e.g.
+ <link linkend="structure-core-script"><filename>&OE_INIT_FILE;</filename></link>
+ or
+ <link linkend="structure-memres-core-script"><filename>oe-init-build-env-memres</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 <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ 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>
+ or
+ <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>).
+ </para>
+
+ <para>
+ It is also possible to place output and configuration
+ files in a directory separate from the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>
+ by providing a directory name when you <filename>source</filename>
+ the setup script.
+ For information on separating output from your local
+ Source Directory files, see the
+ "<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>
+ and
+ "<link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>"
+ sections.
+ </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 a sub-folder.
+ For example, the files for this 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 OpenEmbedded Core metadata.
+ The directory holds recipes, common classes, and machine
+ configuration for emulated targets (<filename>qemux86</filename>,
+ <filename>qemuarm</filename>, and so forth.)
+ </para>
+ </section>
+
+ <section id='structure-core-meta-yocto'>
+ <title><filename>meta-yocto/</filename></title>
+
+ <para>
+ This directory contains the configuration for 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.
+ </para>
+
+ <para>
+ 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>
+ and
+ <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>
+ scripts append 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 is one of two scripts that set up the OpenEmbedded build
+ environment.
+ For information on the other script, see the
+ "<link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>"
+ section.
+ </para>
+
+ <para>
+ 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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ is created, your working directory becomes the Build Directory,
+ and you are presented with a list of common BitBake targets.
+ 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
+ adt-installer
+ meta-ide-support
+
+ You can also run generated qemu images with a command like 'runqemu qemux86'
+ </literallayout>
+ The script gets its default list of common targets from the
+ <filename>conf-notes.txt</filename> file, which is found in the
+ <filename>meta-yocto</filename> directory within the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ Should you have custom distributions, it is very easy to modify
+ this configuration file to include your targets for 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 Manual for more
+ information.
+ </para>
+
+ <para>
+ By default, running this script without a
+ <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ 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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>:
+ <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-yocto/conf</filename> directory in the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ 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 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-memres-core-script'>
+ <title><filename>oe-init-build-env-memres</filename></title>
+
+ <para>
+ This script is one of two scripts that set up the OpenEmbedded
+ build environment.
+ Aside from setting up the environment, this script starts a
+ memory-resident BitBake server.
+ For information on the other setup script, see the
+ "<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>"
+ section.
+ </para>
+
+ <para>
+ Memory-resident BitBake resides in memory until you specifically
+ remove it using the following BitBake command:
+ <literallayout class='monospaced'>
+ $ bitbake -m
+ </literallayout>
+ </para>
+
+ <para>
+ 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.
+ One of these variables is the
+ <link linkend='var-BBSERVER'><filename>BBSERVER</filename></link>
+ variable, which allows the OpenEmbedded build system to locate
+ the server that is running BitBake.
+ </para>
+
+ <para>
+ You need to run an environment setup script before using BitBake
+ commands.
+ Following is the script syntax:
+ <literallayout class='monospaced'>
+ $ source oe-init-build-env-memres <replaceable>port_number</replaceable> <replaceable>build_dir</replaceable>
+ </literallayout>
+ Following are some considerations when sourcing this script:
+ <itemizedlist>
+ <listitem><para>
+ The script uses other scripts within the
+ <filename>scripts</filename> directory to do the bulk of
+ the work.
+ </para></listitem>
+ <listitem><para>
+ If you do not provide a port number with the script, the
+ BitBake server starts at a randomly selected port.
+ </para></listitem>
+ <listitem><para>
+ The script's parameters are positionally dependent.
+ Consequently, you cannot run the script and provide a
+ <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ name without also providing a port number.
+ In other words, the following syntax is illegal:
+ <literallayout class='monospaced'>
+ $ source oe-initbuild-env-memres <replaceable>build_dir</replaceable>
+ </literallayout>
+ <note>
+ The previous restriction might be resolved in the
+ future.
+ See
+ <ulink url='https://bugzilla.yoctoproject.org/show_bug.cgi?id=7555'>Bug 7555</ulink>
+ for more information.
+ </note>
+ </para></listitem>
+ </itemizedlist>
+ </para>
+
+ <para>
+ When you run this script, your Yocto Project environment is set
+ up, a Build Directory is created, your working directory becomes
+ the Build Directory, and you are presented with a list of common
+ BitBake targets.
+ Here is an example:
+ <literallayout class='monospaced'>
+ $ source oe-init-build-env-memres
+ No port specified, using dynamically selected port
+
+ ### Shell environment set up for builds. ###
+
+ You can now run 'bitbake <target>'
+
+ Common targets are:
+ core-image-minimal
+ core-image-sato
+ meta-toolchain
+ adt-installer
+ meta-ide-support
+
+ You can also run generated qemu images with a command like 'runqemu qemux86'
+ Bitbake server address: 127.0.0.1, server port: 53995
+ Bitbake server started on demand as needed, use bitbake -m to shut it down
+ </literallayout>
+ The script gets its default list of common targets from the
+ <filename>conf-notes.txt</filename> file, which is found in the
+ <filename>meta-yocto</filename> directory within the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ Should you have custom distributions, it is very easy to modify
+ this configuration file to include your targets for 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 Manual for more
+ information.
+ </para>
+
+ <para>
+ By default, running this script without a
+ <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ argument creates a build directory named
+ <filename>build</filename>.
+ If you provide a Build Directory argument and port number when you
+ <filename>source</filename> the script, the Build Directory is
+ created using that name.
+ For example, the following command starts the BitBake server using
+ port 53995 and creates a Build Directory named
+ <filename>mybuilds</filename> that is outside of the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>:
+ <literallayout class='monospaced'>
+ $ source oe-init-build-env-memres 53995 ~/mybuilds
+ </literallayout>
+ The <filename>oe-init-build-env-memres</filename> script starts a
+ memory resident BitBake server.
+ This BitBake instance uses the
+ <filename>bitbake-cookerdaemon.log</filename> file, which is
+ located in the Build Directory.
+ </para>
+
+ <para>
+ The OpenEmbedded build system uses the template configuration
+ files, which are found by default in the
+ <filename>meta-yocto/conf</filename> directory in the
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ 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 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-build-env-memres</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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+ when you run one of the build environment setup scripts (i.e.
+ <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>
+ or
+ <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>).
+ </para>
+
+ <para>
+ If you do not give the Build Directory a specific name when you run
+ a setup script, the name defaults to <filename>build</filename>.
+ </para>
+
+ <para>
+ The
+ <link linkend='var-TOPDIR'><filename>TOPDIR</filename></link> variable
+ points to the Build Directory.
+ </para>
+
+ <section id='structure-build-buildhistory'>
+ <title><filename>build/buildhistory</filename></title>
+
+ <para>
+ The OpenEmbedded build system creates this directory when you
+ enable the build history feature.
+ The directory tracks build information into image, packages, and
+ SDK subdirectories.
+ For information on the build history feature, see the
+ "<link linkend='maintaining-build-output-quality'>Maintaining Build Output Quality</link>"
+ section.
+ </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 these
+ variables are relatively rare.
+ </para>
+
+ <para>
+ Edit this file to set the
+ <filename><link linkend='var-MACHINE'>MACHINE</link></filename>
+ for which you want to build, 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 (i.e.
+ <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>
+ or
+ <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>).
+ </para>
+
+ <para>
+ The source <filename>local.conf.sample</filename> file used
+ depends on the <filename>$TEMPLATECONF</filename> script variable,
+ which defaults to <filename>meta-yocto/conf</filename>
+ when you are building from the Yocto Project development
+ environment and defaults to <filename>meta/conf</filename> when
+ you are building from the OpenEmbedded Core environment.
+ Because the script variable points to the source of the
+ <filename>local.conf.sample</filename> file, this implies that
+ you can configure your build environment from any layer by setting
+ the variable in the top-level build environment setup script as
+ follows:
+ <literallayout class='monospaced'>
+ TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
+ </literallayout>
+ Once the build process gets the sample file, it uses
+ <filename>sed</filename> to substitute final
+ <filename>${</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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ You can find the Yocto Project version of the
+ <filename>local.conf.sample</filename> file in the
+ <filename>meta-yocto/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>
+ or
+ <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>).
+ </para>
+
+ <para>
+ The source <filename>bblayers.conf.sample</filename> file used
+ depends on the <filename>$TEMPLATECONF</filename> script variable,
+ which defaults to <filename>meta-yocto/conf</filename>
+ when you are building from the Yocto Project development
+ environment and defaults to <filename>meta/conf</filename> when
+ you are building from the OpenEmbedded Core environment.
+ Because the script variable points to the source of the
+ <filename>bblayers.conf.sample</filename> file, this implies that
+ you can base your build from any layer by setting the variable in
+ the top-level build environment setup script as follows:
+ <literallayout class='monospaced'>
+ TEMPLATECONF=<replaceable>your_layer</replaceable>/conf
+ </literallayout>
+ Once the build process gets the sample file, it uses
+ <filename>sed</filename> to substitute final
+ <filename>${</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
+ <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+ You can find the Yocto Project version of the
+ <filename>bblayers.conf.sample</filename> file in the
+ <filename>meta-yocto/conf</filename> directory.
+ </note>
+ </para>
+ </section>
+
+ <section id='structure-build-conf-sanity_info'>
+ <title><filename>build/conf/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, it creates a cache file of the result that can
+ be used when subsequently running commands.
+ BitBake stores these results here on a per-machine basis.
+ </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
+ "<link linkend='images-dev-environment'>Images</link>" and
+ "<link linkend='sdk-dev-environment'>Application Development SDK</link>"
+ sections.
+ </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.
+ </para>
+ </section>
+
+ <section id='structure-build-tmp-deploy-images'>
+ <title><filename>build/tmp/deploy/images/</filename></title>
+
+ <para>
+ This directory receives complete filesystem images.
+ If you want to flash the resulting image from a build onto a device, look here for the image.
+ </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>, <filename>hob-image-*</filename>,
+ etc.).
+ 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_ADT_URL;#optionally-building-a-toolchain-installer'>Optionally Building a Toolchain Installer</ulink>"
+ section in the Yocto Project Application Developer's Guide.
+ </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'>
+ <title><filename>build/tmp/sysroots/</filename></title>
+
+ <para>
+ This directory contains shared header files and libraries as well as other shared
+ data.
+ Packages that need to share output with other packages do so within this directory.
+ The directory is subdivided by architecture so multiple builds can run within
+ the one Build Directory.
+ </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>
+ </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><link linkend='var-WORKDIR'>WORKDIR</link></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 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-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,
+ <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink> 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-qt'>
+ <title><filename>meta/recipes-qt/</filename></title>
+
+ <para>
+ This directory contains all things related to the Qt application framework.
+ </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
+-->