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/sdk-manual/sdk-extensible.xml b/poky/documentation/sdk-manual/sdk-extensible.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='sdk-extensible'>
+
+ <title>Using the Extensible SDK</title>
+
+ <para>
+ This chapter describes the extensible SDK and how to install it.
+ Information covers the pieces of the SDK, how to install it, and
+ presents a look at using the <filename>devtool</filename>
+ functionality.
+ The extensible SDK makes it easy to add new applications and libraries
+ to an image, modify the source for an existing component, test
+ changes on the target hardware, and ease integration into the rest of
+ the
+ <ulink url='&YOCTO_DOCS_REF_URL;#build-system-term'>OpenEmbedded build system</ulink>.
+ <note>
+ For a side-by-side comparison of main features supported for an
+ extensible SDK as compared to a standard SDK, see the
+ "<link linkend='sdk-manual-intro'>Introduction</link>"
+ section.
+ </note>
+ </para>
+
+ <para>
+ In addition to the functionality available through
+ <filename>devtool</filename>, you can alternatively make use of the
+ toolchain directly, for example from Makefile and Autotools.
+ See the
+ "<link linkend='sdk-working-projects'>Using the SDK Toolchain Directly</link>"
+ chapter for more information.
+ </para>
+
+ <section id='sdk-extensible-sdk-intro'>
+ <title>Why use the Extensible SDK and What is in It?</title>
+
+ <para>
+ The extensible SDK provides a cross-development toolchain and
+ libraries tailored to the contents of a specific image.
+ You would use the Extensible SDK if you want a toolchain experience
+ supplemented with the powerful set of <filename>devtool</filename>
+ commands tailored for the Yocto Project environment.
+ </para>
+
+ <para>
+ The installed extensible SDK consists of several files and
+ directories.
+ Basically, it contains an SDK environment setup script, some
+ configuration files, an internal build system, and the
+ <filename>devtool</filename> functionality.
+ </para>
+ </section>
+
+ <section id='sdk-installing-the-extensible-sdk'>
+ <title>Installing the Extensible SDK</title>
+
+ <para>
+ The first thing you need to do is install the SDK on your
+ <ulink url='&YOCTO_DOCS_REF_URL;#hardware-build-system-term'>Build Host</ulink>
+ by running the <filename>*.sh</filename> installation script.
+ </para>
+
+ <para>
+ You can download a tarball installer, which includes the
+ pre-built toolchain, the <filename>runqemu</filename>
+ script, the internal build system, <filename>devtool</filename>,
+ and support files from the appropriate
+ <ulink url='&YOCTO_TOOLCHAIN_DL_URL;'>toolchain</ulink>
+ directory within the Index of Releases.
+ Toolchains are available for several 32-bit and 64-bit
+ architectures with the <filename>x86_64</filename> directories,
+ respectively.
+ The toolchains the Yocto Project provides are based off the
+ <filename>core-image-sato</filename> and
+ <filename>core-image-minimal</filename> images and contain
+ libraries appropriate for developing against that image.
+ </para>
+
+ <para>
+ The names of the tarball installer scripts are such that a
+ string representing the host system appears first in the
+ filename and then is immediately followed by a string
+ representing the target architecture.
+ An extensible SDK has the string "-ext" as part of the name.
+ Following is the general form:
+ <literallayout class='monospaced'>
+ poky-glibc-<replaceable>host_system</replaceable>-<replaceable>image_type</replaceable>-<replaceable>arch</replaceable>-toolchain-ext-<replaceable>release_version</replaceable>.sh
+
+ Where:
+ <replaceable>host_system</replaceable> is a string representing your development system:
+
+ i686 or x86_64.
+
+ <replaceable>image_type</replaceable> is the image for which the SDK was built:
+
+ core-image-sato or core-image-minimal
+
+ <replaceable>arch</replaceable> is a string representing the tuned target architecture:
+
+ aarch64, armv5e, core2-64, i586, mips32r2, mips64, ppc7400, or cortexa8hf-neon
+
+ <replaceable>release_version</replaceable> is a string representing the release number of the Yocto Project:
+
+ &DISTRO;, &DISTRO;+snapshot
+ </literallayout>
+ For example, the following SDK installer is for a 64-bit
+ development host system and a i586-tuned target architecture
+ based off the SDK for <filename>core-image-sato</filename> and
+ using the current &DISTRO; snapshot:
+ <literallayout class='monospaced'>
+ poky-glibc-x86_64-core-image-sato-i586-toolchain-ext-&DISTRO;.sh
+ </literallayout>
+ <note>
+ As an alternative to downloading an SDK, you can build the
+ SDK installer.
+ For information on building the installer, see the
+ "<link linkend='sdk-building-an-sdk-installer'>Building an SDK Installer</link>"
+ section.
+ </note>
+ </para>
+
+ <para>
+ The SDK and toolchains are self-contained and by default are
+ installed into the <filename>poky_sdk</filename> folder in your
+ home directory.
+ You can choose to install the extensible SDK in any location when
+ you run the installer.
+ However, because files need to be written under that directory
+ during the normal course of operation, the location you choose
+ for installation must be writable for whichever
+ users need to use the SDK.
+ </para>
+
+ <para>
+ The following command shows how to run the installer given a
+ toolchain tarball for a 64-bit x86 development host system and
+ a 64-bit x86 target architecture.
+ The example assumes the SDK installer is located in
+ <filename>~/Downloads/</filename> and has execution rights.
+ <note>
+ If you do not have write permissions for the directory
+ into which you are installing the SDK, the installer
+ notifies you and exits.
+ For that case, set up the proper permissions in the directory
+ and run the installer again.
+ </note>
+ <literallayout class='monospaced'>
+ $ ./Downloads/poky-glibc-x86_64-core-image-minimal-core2-64-toolchain-ext-2.5.sh
+ Poky (Yocto Project Reference Distro) Extensible SDK installer version 2.5
+ ==========================================================================
+ Enter target directory for SDK (default: ~/poky_sdk):
+ You are about to install the SDK to "/home/scottrif/poky_sdk". Proceed [Y/n]? Y
+ Extracting SDK..............done
+ Setting it up...
+ Extracting buildtools...
+ Preparing build system...
+ Parsing recipes: 100% |##################################################################| Time: 0:00:52
+ Initialising tasks: 100% |###############################################################| Time: 0:00:00
+ Checking sstate mirror object availability: 100% |#######################################| Time: 0:00:00
+ Loading cache: 100% |####################################################################| Time: 0:00:00
+ Initialising tasks: 100% |###############################################################| Time: 0:00:00
+ done
+ SDK has been successfully set up and is ready to be used.
+ Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g.
+ $ . /home/scottrif/poky_sdk/environment-setup-core2-64-poky-linux
+
+ </literallayout>
+ </para>
+ </section>
+
+ <section id='sdk-running-the-extensible-sdk-environment-setup-script'>
+ <title>Running the Extensible SDK Environment Setup Script</title>
+
+ <para>
+ Once you have the SDK installed, you must run the SDK environment
+ setup script before you can actually use the SDK.
+ This setup script resides in the directory you chose when you
+ installed the SDK, which is either the default
+ <filename>poky_sdk</filename> directory or the directory you
+ chose during installation.
+ </para>
+
+ <para>
+ Before running the script, be sure it is the one that matches the
+ architecture for which you are developing.
+ Environment setup scripts begin with the string
+ "<filename>environment-setup</filename>" and include as part of
+ their name the tuned target architecture.
+ As an example, the following commands set the working directory
+ to where the SDK was installed and then source the environment
+ setup script.
+ In this example, the setup script is for an IA-based
+ target machine using i586 tuning:
+ <literallayout class='monospaced'>
+ $ cd /home/scottrif/poky_sdk
+ $ source environment-setup-core2-64-poky-linux
+ SDK environment now set up; additionally you may now run devtool to perform development tasks.
+ Run devtool --help for further details.
+ </literallayout>
+ Running the setup script defines many environment variables needed
+ in order to use the SDK (e.g. <filename>PATH</filename>,
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>,
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-LD'><filename>LD</filename></ulink>,
+ and so forth).
+ If you want to see all the environment variables the script
+ exports, examine the installation file itself.
+ </para>
+ </section>
+
+ <section id='using-devtool-in-your-sdk-workflow'>
+ <title>Using <filename>devtool</filename> in Your SDK Workflow</title>
+
+ <para>
+ The cornerstone of the extensible SDK is a command-line tool
+ called <filename>devtool</filename>.
+ This tool provides a number of features that help
+ you build, test and package software within the extensible SDK, and
+ optionally integrate it into an image built by the OpenEmbedded
+ build system.
+ <note><title>Tip</title>
+ The use of <filename>devtool</filename> is not limited to
+ the extensible SDK.
+ You can use <filename>devtool</filename> to help you easily
+ develop any project whose build output must be part of an
+ image built using the build system.
+ </note>
+ </para>
+
+ <para>
+ The <filename>devtool</filename> command line is organized
+ similarly to
+ <ulink url='&YOCTO_DOCS_OM_URL;#git'>Git</ulink> in that it
+ has a number of sub-commands for each function.
+ You can run <filename>devtool --help</filename> to see all the
+ commands.
+ <note>
+ See the
+ "<ulink url='&YOCTO_DOCS_REF_URL;#ref-devtool-reference'><filename>devtool</filename> Quick Reference</ulink>"
+ in the Yocto Project Reference Manual for a
+ <filename>devtool</filename> quick reference.
+ </note>
+ </para>
+
+ <para>
+ Three <filename>devtool</filename> subcommands exist that provide
+ entry-points into development:
+ <itemizedlist>
+ <listitem><para>
+ <emphasis><filename>devtool add</filename></emphasis>:
+ Assists in adding new software to be built.
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>devtool modify</filename></emphasis>:
+ Sets up an environment to enable you to modify the source of
+ an existing component.
+ </para></listitem>
+ <listitem><para>
+ <emphasis><filename>devtool upgrade</filename></emphasis>:
+ Updates an existing recipe so that you can build it for
+ an updated set of source files.
+ </para></listitem>
+ </itemizedlist>
+ As with the build system, "recipes" represent software packages
+ within <filename>devtool</filename>.
+ When you use <filename>devtool add</filename>, a recipe is
+ automatically created.
+ When you use <filename>devtool modify</filename>, the specified
+ existing recipe is used in order to determine where to get the
+ source code and how to patch it.
+ In both cases, an environment is set up so that when you build the
+ recipe a source tree that is under your control is used in order to
+ allow you to make changes to the source as desired.
+ By default, new recipes and the source go into a "workspace"
+ directory under the SDK.
+ </para>
+
+ <para>
+ The remainder of this section presents the
+ <filename>devtool add</filename>,
+ <filename>devtool modify</filename>, and
+ <filename>devtool upgrade</filename> workflows.
+ </para>
+
+ <section id='sdk-use-devtool-to-add-an-application'>
+ <title>Use <filename>devtool add</filename> to Add an Application</title>
+
+ <para>
+ The <filename>devtool add</filename> command generates
+ a new recipe based on existing source code.
+ This command takes advantage of the
+ <ulink url='&YOCTO_DOCS_REF_URL;#devtool-the-workspace-layer-structure'>workspace</ulink>
+ layer that many <filename>devtool</filename> commands
+ use.
+ The command is flexible enough to allow you to extract source
+ code into both the workspace or a separate local Git repository
+ and to use existing code that does not need to be extracted.
+ </para>
+
+ <para>
+ Depending on your particular scenario, the arguments and options
+ you use with <filename>devtool add</filename> form different
+ combinations.
+ The following diagram shows common development flows
+ you would use with the <filename>devtool add</filename>
+ command:
+ </para>
+
+ <para>
+ <imagedata fileref="figures/sdk-devtool-add-flow.png" align="center" />
+ </para>
+
+ <para>
+ <orderedlist>
+ <listitem><para><emphasis>Generating the New Recipe</emphasis>:
+ The top part of the flow shows three scenarios by which
+ you could use <filename>devtool add</filename> to
+ generate a recipe based on existing source code.</para>
+
+ <para>In a shared development environment, it is
+ typical for other developers to be responsible for
+ various areas of source code.
+ As a developer, you are probably interested in using
+ that source code as part of your development within
+ the Yocto Project.
+ All you need is access to the code, a recipe, and a
+ controlled area in which to do your work.</para>
+
+ <para>Within the diagram, three possible scenarios
+ feed into the <filename>devtool add</filename> workflow:
+ <itemizedlist>
+ <listitem><para>
+ <emphasis>Left</emphasis>:
+ The left scenario in the figure represents a
+ common situation where the source code does not
+ exist locally and needs to be extracted.
+ In this situation, the source code is extracted
+ to the default workspace - you do not
+ want the files in some specific location
+ outside of the workspace.
+ Thus, everything you need will be located in
+ the workspace:
+ <literallayout class='monospaced'>
+ $ devtool add <replaceable>recipe fetchuri</replaceable>
+ </literallayout>
+ With this command, <filename>devtool</filename>
+ extracts the upstream source files into a local
+ Git repository within the
+ <filename>sources</filename> folder.
+ The command then creates a recipe named
+ <replaceable>recipe</replaceable> and a
+ corresponding append file in the workspace.
+ If you do not provide
+ <replaceable>recipe</replaceable>, the command
+ makes an attempt to determine the recipe name.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Middle</emphasis>:
+ The middle scenario in the figure also
+ represents a situation where the source code
+ does not exist locally.
+ In this case, the code is again upstream
+ and needs to be extracted to some
+ local area - this time outside of the default
+ workspace.
+ <note>
+ If required, <filename>devtool</filename>
+ always creates
+ a Git repository locally during the
+ extraction.
+ </note>
+ Furthermore, the first positional argument
+ <replaceable>srctree</replaceable> in this
+ case identifies where the
+ <filename>devtool add</filename> command
+ will locate the extracted code outside of the
+ workspace.
+ You need to specify an empty directory:
+ <literallayout class='monospaced'>
+ $ devtool add <replaceable>recipe srctree fetchuri</replaceable>
+ </literallayout>
+ In summary, the source code is pulled from
+ <replaceable>fetchuri</replaceable> and
+ extracted into the location defined by
+ <replaceable>srctree</replaceable> as a local
+ Git repository.</para>
+
+ <para>Within workspace,
+ <filename>devtool</filename> creates a
+ recipe named <replaceable>recipe</replaceable>
+ along with an associated append file.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Right</emphasis>:
+ The right scenario in the figure represents a
+ situation where the
+ <replaceable>srctree</replaceable> has been
+ previously prepared outside of the
+ <filename>devtool</filename> workspace.</para>
+
+ <para>The following command provides a new
+ recipe name and identifies the existing source
+ tree location:
+ <literallayout class='monospaced'>
+ $ devtool add <replaceable>recipe srctree</replaceable>
+ </literallayout>
+ The command examines the source code and
+ creates a recipe named
+ <replaceable>recipe</replaceable> for the code
+ and places the recipe into the workspace.
+ </para>
+
+ <para>Because the extracted source code already
+ exists, <filename>devtool</filename> does not
+ try to relocate the source code into the
+ workspace - only the new recipe is placed
+ in the workspace.</para>
+
+ <para>Aside from a recipe folder, the command
+ also creates an associated append folder and
+ places an initial
+ <filename>*.bbappend</filename> file within.
+ </para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Edit the Recipe</emphasis>:
+ You can use <filename>devtool edit-recipe</filename>
+ to open up the editor as defined by the
+ <filename>$EDITOR</filename> environment variable
+ and modify the file:
+ <literallayout class='monospaced'>
+ $ devtool edit-recipe <replaceable>recipe</replaceable>
+ </literallayout>
+ From within the editor, you can make modifications to
+ the recipe that take affect when you build it later.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Build the Recipe or Rebuild the Image</emphasis>:
+ The next step you take depends on what you are going
+ to do with the new code.</para>
+
+ <para>If you need to eventually move the build output
+ to the target hardware, use the following
+ <filename>devtool</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build <replaceable>recipe</replaceable>
+ </literallayout></para>
+
+ <para>On the other hand, if you want an image to
+ contain the recipe's packages from the workspace
+ for immediate deployment onto a device (e.g. for
+ testing purposes), you can use
+ the <filename>devtool build-image</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build-image <replaceable>image</replaceable>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Deploy the Build Output</emphasis>:
+ When you use the <filename>devtool build</filename>
+ command to build out your recipe, you probably want to
+ see if the resulting build output works as expected
+ on the target hardware.
+ <note>
+ This step assumes you have a previously built
+ image that is already either running in QEMU or
+ is running on actual hardware.
+ Also, it is assumed that for deployment of the
+ image to the target, SSH is installed in the image
+ and, if the image is running on real hardware,
+ you have network access to and from your
+ development machine.
+ </note>
+ You can deploy your build output to that target
+ hardware by using the
+ <filename>devtool deploy-target</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool deploy-target <replaceable>recipe target</replaceable>
+ </literallayout>
+ The <replaceable>target</replaceable> is a live target
+ machine running as an SSH server.</para>
+
+ <para>You can, of course, also deploy the image you
+ build to actual hardware by using the
+ <filename>devtool build-image</filename> command.
+ However, <filename>devtool</filename> does not provide
+ a specific command that allows you to deploy the
+ image to actual hardware.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Finish Your Work With the Recipe</emphasis>:
+ The <filename>devtool finish</filename> command creates
+ any patches corresponding to commits in the local
+ Git repository, moves the new recipe to a more permanent
+ layer, and then resets the recipe so that the recipe is
+ built normally rather than from the workspace.
+ <literallayout class='monospaced'>
+ $ devtool finish <replaceable>recipe layer</replaceable>
+ </literallayout>
+ <note>
+ Any changes you want to turn into patches must be
+ committed to the Git repository in the source tree.
+ </note></para>
+
+ <para>As mentioned, the
+ <filename>devtool finish</filename> command moves the
+ final recipe to its permanent layer.
+ </para>
+
+ <para>As a final process of the
+ <filename>devtool finish</filename> command, the state
+ of the standard layers and the upstream source is
+ restored so that you can build the recipe from those
+ areas rather than the workspace.
+ <note>
+ You can use the <filename>devtool reset</filename>
+ command to put things back should you decide you
+ do not want to proceed with your work.
+ If you do use this command, realize that the source
+ tree is preserved.
+ </note>
+ </para></listitem>
+ </orderedlist>
+ </para>
+ </section>
+
+ <section id='sdk-devtool-use-devtool-modify-to-modify-the-source-of-an-existing-component'>
+ <title>Use <filename>devtool modify</filename> to Modify the Source of an Existing Component</title>
+
+ <para>
+ The <filename>devtool modify</filename> command prepares the
+ way to work on existing code that already has a local recipe in
+ place that is used to build the software.
+ The command is flexible enough to allow you to extract code
+ from an upstream source, specify the existing recipe, and
+ keep track of and gather any patch files from other developers
+ that are associated with the code.
+ </para>
+
+ <para>
+ Depending on your particular scenario, the arguments and options
+ you use with <filename>devtool modify</filename> form different
+ combinations.
+ The following diagram shows common development flows for the
+ <filename>devtool modify</filename> command:
+ </para>
+
+ <para>
+ <imagedata fileref="figures/sdk-devtool-modify-flow.png" align="center" />
+ </para>
+
+ <para>
+ <orderedlist>
+ <listitem><para>
+ <emphasis>Preparing to Modify the Code</emphasis>:
+ The top part of the flow shows three scenarios by which
+ you could use <filename>devtool modify</filename> to
+ prepare to work on source files.
+ Each scenario assumes the following:
+ <itemizedlist>
+ <listitem><para>
+ The recipe exists locally in a layer external
+ to the <filename>devtool</filename> workspace.
+ </para></listitem>
+ <listitem><para>
+ The source files exist either upstream in an
+ un-extracted state or locally in a previously
+ extracted state.
+ </para></listitem>
+ </itemizedlist>
+ The typical situation is where another developer has
+ created a layer for use with the Yocto Project and
+ their recipe already resides in that layer.
+ Furthermore, their source code is readily available
+ either upstream or locally.
+ <itemizedlist>
+ <listitem><para>
+ <emphasis>Left</emphasis>:
+ The left scenario in the figure represents a
+ common situation where the source code does
+ not exist locally and it needs to be extracted
+ from an upstream source.
+ In this situation, the source is extracted
+ into the default <filename>devtool</filename>
+ workspace location.
+ The recipe, in this scenario, is in its own
+ layer outside the workspace
+ (i.e.
+ <filename>meta-</filename><replaceable>layername</replaceable>).
+ </para>
+
+ <para>The following command identifies the
+ recipe and, by default, extracts the source
+ files:
+ <literallayout class='monospaced'>
+ $ devtool modify <replaceable>recipe</replaceable>
+ </literallayout>
+ Once <filename>devtool</filename>locates the
+ recipe, <filename>devtool</filename> uses the
+ recipe's
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+ statements to locate the source code and any
+ local patch files from other developers.</para>
+
+ <para>With this scenario, no
+ <replaceable>srctree</replaceable> argument
+ exists.
+ Consequently, the default behavior of the
+ <filename>devtool modify</filename> command is
+ to extract the source files pointed to by the
+ <filename>SRC_URI</filename> statements into a
+ local Git structure.
+ Furthermore, the location for the extracted
+ source is the default area within the
+ <filename>devtool</filename> workspace.
+ The result is that the command sets up both
+ the source code and an append file within the
+ workspace while the recipe remains in its
+ original location.</para>
+
+ <para>Additionally, if you have any non-patch
+ local files (i.e. files referred to with
+ <filename>file://</filename> entries in
+ <filename>SRC_URI</filename> statement excluding
+ <filename>*.patch/</filename> or
+ <filename>*.diff</filename>), these files are
+ copied to an
+ <filename>oe-local-files</filename> folder
+ under the newly created source tree.
+ Copying the files here gives you a convenient
+ area from which you can modify the files.
+ Any changes or additions you make to those
+ files are incorporated into the build the next
+ time you build the software just as are other
+ changes you might have made to the source.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Middle</emphasis>:
+ The middle scenario in the figure represents a
+ situation where the source code also does not
+ exist locally.
+ In this case, the code is again upstream
+ and needs to be extracted to some
+ local area as a Git repository.
+ The recipe, in this scenario, is again local
+ and in its own layer outside the workspace.
+ </para>
+
+ <para>The following command tells
+ <filename>devtool</filename> the recipe with
+ which to work and, in this case, identifies a
+ local area for the extracted source files that
+ exists outside of the default
+ <filename>devtool</filename> workspace:
+ <literallayout class='monospaced'>
+ $ devtool modify <replaceable>recipe srctree</replaceable>
+ </literallayout>
+ <note>
+ You cannot provide a URL for
+ <replaceable>srctree</replaceable> using
+ the <filename>devtool</filename> command.
+ </note>
+ As with all extractions, the command uses
+ the recipe's <filename>SRC_URI</filename>
+ statements to locate the source files and any
+ associated patch files.
+ Non-patch files are copied to an
+ <filename>oe-local-files</filename> folder
+ under the newly created source tree.</para>
+
+ <para>Once the files are located, the command
+ by default extracts them into
+ <replaceable>srctree</replaceable>.</para>
+
+ <para>Within workspace,
+ <filename>devtool</filename> creates an append
+ file for the recipe.
+ The recipe remains in its original location but
+ the source files are extracted to the location
+ you provide with
+ <replaceable>srctree</replaceable>.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Right</emphasis>:
+ The right scenario in the figure represents a
+ situation where the source tree
+ (<replaceable>srctree</replaceable>) already
+ exists locally as a previously extracted Git
+ structure outside of the
+ <filename>devtool</filename> workspace.
+ In this example, the recipe also exists
+ elsewhere locally in its own layer.
+ </para>
+
+ <para>The following command tells
+ <filename>devtool</filename> the recipe
+ with which to work, uses the "-n" option to
+ indicate source does not need to be extracted,
+ and uses <replaceable>srctree</replaceable> to
+ point to the previously extracted source files:
+ <literallayout class='monospaced'>
+ $ devtool modify -n <replaceable>recipe srctree</replaceable>
+ </literallayout>
+ </para>
+
+ <para>If an <filename>oe-local-files</filename>
+ subdirectory happens to exist and it contains
+ non-patch files, the files are used.
+ However, if the subdirectory does not exist and
+ you run the <filename>devtool finish</filename>
+ command, any non-patch files that might exist
+ next to the recipe are removed because it
+ appears to <filename>devtool</filename> that
+ you have deleted those files.</para>
+
+ <para>Once the
+ <filename>devtool modify</filename> command
+ finishes, it creates only an append file for
+ the recipe in the <filename>devtool</filename>
+ workspace.
+ The recipe and the source code remain in their
+ original locations.
+ </para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Edit the Source</emphasis>:
+ Once you have used the
+ <filename>devtool modify</filename> command, you are
+ free to make changes to the source files.
+ You can use any editor you like to make and save
+ your source code modifications.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Build the Recipe or Rebuild the Image</emphasis>:
+ The next step you take depends on what you are going
+ to do with the new code.</para>
+
+ <para>If you need to eventually move the build output
+ to the target hardware, use the following
+ <filename>devtool</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build <replaceable>recipe</replaceable>
+ </literallayout></para>
+
+ <para>On the other hand, if you want an image to
+ contain the recipe's packages from the workspace
+ for immediate deployment onto a device (e.g. for
+ testing purposes), you can use
+ the <filename>devtool build-image</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build-image <replaceable>image</replaceable>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Deploy the Build Output</emphasis>:
+ When you use the <filename>devtool build</filename>
+ command to build out your recipe, you probably want to
+ see if the resulting build output works as expected
+ on target hardware.
+ <note>
+ This step assumes you have a previously built
+ image that is already either running in QEMU or
+ running on actual hardware.
+ Also, it is assumed that for deployment of the image
+ to the target, SSH is installed in the image and if
+ the image is running on real hardware that you have
+ network access to and from your development machine.
+ </note>
+ You can deploy your build output to that target
+ hardware by using the
+ <filename>devtool deploy-target</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool deploy-target <replaceable>recipe target</replaceable>
+ </literallayout>
+ The <replaceable>target</replaceable> is a live target
+ machine running as an SSH server.</para>
+
+ <para>You can, of course, use other methods to deploy
+ the image you built using the
+ <filename>devtool build-image</filename> command to
+ actual hardware.
+ <filename>devtool</filename> does not provide
+ a specific command to deploy the image to actual
+ hardware.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Finish Your Work With the Recipe</emphasis>:
+ The <filename>devtool finish</filename> command creates
+ any patches corresponding to commits in the local
+ Git repository, updates the recipe to point to them
+ (or creates a <filename>.bbappend</filename> file to do
+ so, depending on the specified destination layer), and
+ then resets the recipe so that the recipe is built
+ normally rather than from the workspace.
+ <literallayout class='monospaced'>
+ $ devtool finish <replaceable>recipe layer</replaceable>
+ </literallayout>
+ <note>
+ Any changes you want to turn into patches must be
+ staged and committed within the local Git
+ repository before you use the
+ <filename>devtool finish</filename> command.
+ </note></para>
+
+ <para>Because there is no need to move the recipe,
+ <filename>devtool finish</filename> either updates the
+ original recipe in the original layer or the command
+ creates a <filename>.bbappend</filename> file in a
+ different layer as provided by
+ <replaceable>layer</replaceable>.
+ Any work you did in the
+ <filename>oe-local-files</filename> directory is
+ preserved in the original files next to the recipe
+ during the <filename>devtool finish</filename>
+ command.</para>
+
+ <para>As a final process of the
+ <filename>devtool finish</filename> command, the state
+ of the standard layers and the upstream source is
+ restored so that you can build the recipe from those
+ areas rather than from the workspace.
+ <note>
+ You can use the <filename>devtool reset</filename>
+ command to put things back should you decide you
+ do not want to proceed with your work.
+ If you do use this command, realize that the source
+ tree is preserved.
+ </note>
+ </para></listitem>
+ </orderedlist>
+ </para>
+ </section>
+
+ <section id='sdk-devtool-use-devtool-upgrade-to-create-a-version-of-the-recipe-that-supports-a-newer-version-of-the-software'>
+ <title>Use <filename>devtool upgrade</filename> to Create a Version of the Recipe that Supports a Newer Version of the Software</title>
+
+ <para>
+ The <filename>devtool upgrade</filename> command upgrades
+ an existing recipe to that of a more up-to-date version
+ found upstream.
+ Throughout the life of software, recipes continually undergo
+ version upgrades by their upstream publishers.
+ You can use the <filename>devtool upgrade</filename>
+ workflow to make sure your recipes you are using for builds
+ are up-to-date with their upstream counterparts.
+ <note>
+ Several methods exist by which you can upgrade recipes -
+ <filename>devtool upgrade</filename> happens to be one.
+ You can read about all the methods by which you can
+ upgrade recipes in the
+ "<ulink url='&YOCTO_DOCS_DEV_URL;#gs-upgrading-recipes'>Upgrading Recipes</ulink>"
+ section of the Yocto Project Development Tasks Manual.
+ </note>
+ </para>
+
+ <para>
+ The <filename>devtool upgrade</filename> command is flexible
+ enough to allow you to specify source code revision and
+ versioning schemes, extract code into or out of the
+ <filename>devtool</filename>
+ <ulink url='&YOCTO_DOCS_REF_URL;#devtool-the-workspace-layer-structure'>workspace</ulink>,
+ and work with any source file forms that the
+ <ulink url='&YOCTO_DOCS_BB_URL;#bb-fetchers'>fetchers</ulink>
+ support.
+ </para>
+
+ <para>
+ The following diagram shows the common development flow
+ used with the <filename>devtool upgrade</filename> command:
+ </para>
+
+ <para>
+ <imagedata fileref="figures/sdk-devtool-upgrade-flow.png" align="center" />
+ </para>
+
+ <para>
+ <orderedlist>
+ <listitem><para>
+ <emphasis>Initiate the Upgrade</emphasis>:
+ The top part of the flow shows the typical scenario by
+ which you use the <filename>devtool upgrade</filename>
+ command.
+ The following conditions exist:
+ <itemizedlist>
+ <listitem><para>
+ The recipe exists in a local layer external
+ to the <filename>devtool</filename> workspace.
+ </para></listitem>
+ <listitem><para>
+ The source files for the new release
+ exist in the same location pointed to by
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+ in the recipe (e.g. a tarball with the new
+ version number in the name, or as a different
+ revision in the upstream Git repository).
+ </para></listitem>
+ </itemizedlist>
+ A common situation is where third-party software has
+ undergone a revision so that it has been upgraded.
+ The recipe you have access to is likely in your own
+ layer.
+ Thus, you need to upgrade the recipe to use the
+ newer version of the software:
+ <literallayout class='monospaced'>
+ $ devtool upgrade -V <replaceable>version recipe</replaceable>
+ </literallayout>
+ By default, the <filename>devtool upgrade</filename>
+ command extracts source code into the
+ <filename>sources</filename> directory in the
+ <ulink url='&YOCTO_DOCS_REF_URL;#devtool-the-workspace-layer-structure'>workspace</ulink>.
+ If you want the code extracted to any other location,
+ you need to provide the
+ <replaceable>srctree</replaceable> positional argument
+ with the command as follows:
+ <literallayout class='monospaced'>
+ $ devtool upgrade -V <replaceable>version recipe srctree</replaceable>
+ </literallayout>
+ <note>
+ In this example, the "-V" option specifies the new
+ version.
+ If you don't use "-V", the command upgrades the
+ recipe to the latest version.
+ </note>
+ If the source files pointed to by the
+ <filename>SRC_URI</filename> statement in the recipe
+ are in a Git repository, you must provide the "-S"
+ option and specify a revision for the software.</para>
+
+ <para>Once <filename>devtool</filename> locates the
+ recipe, it uses the <filename>SRC_URI</filename>
+ variable to locate the source code and any local patch
+ files from other developers.
+ The result is that the command sets up the source
+ code, the new version of the recipe, and an append file
+ all within the workspace.</para>
+
+ <para>Additionally, if you have any non-patch
+ local files (i.e. files referred to with
+ <filename>file://</filename> entries in
+ <filename>SRC_URI</filename> statement excluding
+ <filename>*.patch/</filename> or
+ <filename>*.diff</filename>), these files are
+ copied to an
+ <filename>oe-local-files</filename> folder
+ under the newly created source tree.
+ Copying the files here gives you a convenient
+ area from which you can modify the files.
+ Any changes or additions you make to those
+ files are incorporated into the build the next
+ time you build the software just as are other
+ changes you might have made to the source.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Resolve any Conflicts created by the Upgrade</emphasis>:
+ Conflicts could exist due to the software being
+ upgraded to a new version.
+ Conflicts occur if your recipe specifies some patch
+ files in <filename>SRC_URI</filename> that conflict
+ with changes made in the new version of the software.
+ For such cases, you need to resolve the conflicts
+ by editing the source and following the normal
+ <filename>git rebase</filename> conflict resolution
+ process.</para>
+
+ <para>Before moving onto the next step, be sure to
+ resolve any such conflicts created through use of a
+ newer or different version of the software.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Build the Recipe or Rebuild the Image</emphasis>:
+ The next step you take depends on what you are going
+ to do with the new code.</para>
+
+ <para>If you need to eventually move the build output
+ to the target hardware, use the following
+ <filename>devtool</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build <replaceable>recipe</replaceable>
+ </literallayout></para>
+
+ <para>On the other hand, if you want an image to
+ contain the recipe's packages from the workspace
+ for immediate deployment onto a device (e.g. for
+ testing purposes), you can use
+ the <filename>devtool build-image</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool build-image <replaceable>image</replaceable>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Deploy the Build Output</emphasis>:
+ When you use the <filename>devtool build</filename>
+ command or <filename>bitbake</filename> to build
+ your recipe, you probably want to see if the resulting
+ build output works as expected on target hardware.
+ <note>
+ This step assumes you have a previously built
+ image that is already either running in QEMU or
+ running on actual hardware.
+ Also, it is assumed that for deployment of the
+ image to the target, SSH is installed in the image
+ and if the image is running on real hardware that
+ you have network access to and from your
+ development machine.
+ </note>
+ You can deploy your build output to that target
+ hardware by using the
+ <filename>devtool deploy-target</filename> command:
+ <literallayout class='monospaced'>
+ $ devtool deploy-target <replaceable>recipe target</replaceable>
+ </literallayout>
+ The <replaceable>target</replaceable> is a live target
+ machine running as an SSH server.</para>
+
+ <para>You can, of course, also deploy the image you
+ build using the
+ <filename>devtool build-image</filename> command
+ to actual hardware.
+ However, <filename>devtool</filename> does not provide
+ a specific command that allows you to do this.
+ </para></listitem>
+ <listitem><para>
+ <emphasis>Finish Your Work With the Recipe</emphasis>:
+ The <filename>devtool finish</filename> command creates
+ any patches corresponding to commits in the local
+ Git repository, moves the new recipe to a more
+ permanent layer, and then resets the recipe so that
+ the recipe is built normally rather than from the
+ workspace.</para>
+
+ <para>Any work you did in the
+ <filename>oe-local-files</filename> directory is
+ preserved in the original files next to the recipe
+ during the <filename>devtool finish</filename>
+ command.</para>
+
+ <para>
+ If you specify a destination layer that is the same as
+ the original source, then the old version of the
+ recipe and associated files are removed prior to
+ adding the new version.
+ <literallayout class='monospaced'>
+ $ devtool finish <replaceable>recipe layer</replaceable>
+ </literallayout>
+ <note>
+ Any changes you want to turn into patches must be
+ committed to the Git repository in the source tree.
+ </note></para>
+
+ <para>As a final process of the
+ <filename>devtool finish</filename> command, the state
+ of the standard layers and the upstream source is
+ restored so that you can build the recipe from those
+ areas rather than the workspace.
+ <note>
+ You can use the <filename>devtool reset</filename>
+ command to put things back should you decide you
+ do not want to proceed with your work.
+ If you do use this command, realize that the source
+ tree is preserved.
+ </note>
+ </para></listitem>
+ </orderedlist>
+ </para>
+ </section>
+ </section>
+
+ <section id='sdk-a-closer-look-at-devtool-add'>
+ <title>A Closer Look at <filename>devtool add</filename></title>
+
+ <para>
+ The <filename>devtool add</filename> command automatically creates
+ a recipe based on the source tree you provide with the command.
+ Currently, the command has support for the following:
+ <itemizedlist>
+ <listitem><para>
+ Autotools (<filename>autoconf</filename> and
+ <filename>automake</filename>)
+ </para></listitem>
+ <listitem><para>
+ CMake
+ </para></listitem>
+ <listitem><para>
+ Scons
+ </para></listitem>
+ <listitem><para>
+ <filename>qmake</filename>
+ </para></listitem>
+ <listitem><para>
+ Plain <filename>Makefile</filename>
+ </para></listitem>
+ <listitem><para>
+ Out-of-tree kernel module
+ </para></listitem>
+ <listitem><para>
+ Binary package (i.e. "-b" option)
+ </para></listitem>
+ <listitem><para>
+ Node.js module
+ </para></listitem>
+ <listitem><para>
+ Python modules that use <filename>setuptools</filename>
+ or <filename>distutils</filename>
+ </para></listitem>
+ </itemizedlist>
+ </para>
+
+ <para>
+ Apart from binary packages, the determination of how a source tree
+ should be treated is automatic based on the files present within
+ that source tree.
+ For example, if a <filename>CMakeLists.txt</filename> file is found,
+ then the source tree is assumed to be using
+ CMake and is treated accordingly.
+ <note>
+ In most cases, you need to edit the automatically generated
+ recipe in order to make it build properly.
+ Typically, you would go through several edit and build cycles
+ until the recipe successfully builds.
+ Once the recipe builds, you could use possible further
+ iterations to test the recipe on the target device.
+ </note>
+ </para>
+
+ <para>
+ The remainder of this section covers specifics regarding how parts
+ of the recipe are generated.
+ </para>
+
+ <section id='sdk-name-and-version'>
+ <title>Name and Version</title>
+
+ <para>
+ If you do not specify a name and version on the command
+ line, <filename>devtool add</filename> uses various metadata
+ within the source tree in an attempt to determine
+ the name and version of the software being built.
+ Based on what the tool determines, <filename>devtool</filename>
+ sets the name of the created recipe file accordingly.
+ </para>
+
+ <para>
+ If <filename>devtool</filename> cannot determine the name and
+ version, the command prints an error.
+ For such cases, you must re-run the command and provide
+ the name and version, just the name, or just the version as
+ part of the command line.
+ </para>
+
+ <para>
+ Sometimes the name or version determined from the source tree
+ might be incorrect.
+ For such a case, you must reset the recipe:
+ <literallayout class='monospaced'>
+ $ devtool reset -n <replaceable>recipename</replaceable>
+ </literallayout>
+ After running the <filename>devtool reset</filename> command,
+ you need to run <filename>devtool add</filename> again and
+ provide the name or the version.
+ </para>
+ </section>
+
+ <section id='sdk-dependency-detection-and-mapping'>
+ <title>Dependency Detection and Mapping</title>
+
+ <para>
+ The <filename>devtool add</filename> command attempts to
+ detect build-time dependencies and map them to other recipes
+ in the system.
+ During this mapping, the command fills in the names of those
+ recipes as part of the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
+ variable within the recipe.
+ If a dependency cannot be mapped, <filename>devtool</filename>
+ places a comment in the recipe indicating such.
+ The inability to map a dependency can result from naming not
+ being recognized or because the dependency simply is not
+ available.
+ For cases where the dependency is not available, you must use
+ the <filename>devtool add</filename> command to add an
+ additional recipe that satisfies the dependency.
+ Once you add that recipe, you need to update the
+ <filename>DEPENDS</filename> variable in the original recipe
+ to include the new recipe.
+ </para>
+
+ <para>
+ If you need to add runtime dependencies, you can do so by
+ adding the following to your recipe:
+ <literallayout class='monospaced'>
+ RDEPENDS_${PN} += "<replaceable>dependency1 dependency2 ...</replaceable>"
+ </literallayout>
+ <note>
+ The <filename>devtool add</filename> command often cannot
+ distinguish between mandatory and optional dependencies.
+ Consequently, some of the detected dependencies might
+ in fact be optional.
+ When in doubt, consult the documentation or the configure
+ script for the software the recipe is building for further
+ details.
+ In some cases, you might find you can substitute the
+ dependency with an option that disables the associated
+ functionality passed to the configure script.
+ </note>
+ </para>
+ </section>
+
+ <section id='sdk-license-detection'>
+ <title>License Detection</title>
+
+ <para>
+ The <filename>devtool add</filename> command attempts to
+ determine if the software you are adding is able to be
+ distributed under a common, open-source license.
+ If so, the command sets the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
+ value accordingly.
+ You should double-check the value added by the command against
+ the documentation or source files for the software you are
+ building and, if necessary, update that
+ <filename>LICENSE</filename> value.
+ </para>
+
+ <para>
+ The <filename>devtool add</filename> command also sets the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
+ value to point to all files that appear to be license-related.
+ Realize that license statements often appear in comments at
+ the top of source files or within the documentation.
+ In such cases, the command does not recognize those license
+ statements.
+ Consequently, you might need to amend the
+ <filename>LIC_FILES_CHKSUM</filename> variable to point to one
+ or more of those comments if present.
+ Setting <filename>LIC_FILES_CHKSUM</filename> is particularly
+ important for third-party software.
+ The mechanism attempts to ensure correct licensing should you
+ upgrade the recipe to a newer upstream version in future.
+ Any change in licensing is detected and you receive an error
+ prompting you to check the license text again.
+ </para>
+
+ <para>
+ If the <filename>devtool add</filename> command cannot
+ determine licensing information, <filename>devtool</filename>
+ sets the <filename>LICENSE</filename> value to "CLOSED" and
+ leaves the <filename>LIC_FILES_CHKSUM</filename> value unset.
+ This behavior allows you to continue with development even
+ though the settings are unlikely to be correct in all cases.
+ You should check the documentation or source files for the
+ software you are building to determine the actual license.
+ </para>
+ </section>
+
+ <section id='sdk-adding-makefile-only-software'>
+ <title>Adding Makefile-Only Software</title>
+
+ <para>
+ The use of Make by itself is very common in both proprietary
+ and open-source software.
+ Unfortunately, Makefiles are often not written with
+ cross-compilation in mind.
+ Thus, <filename>devtool add</filename> often cannot do very
+ much to ensure that these Makefiles build correctly.
+ It is very common, for example, to explicitly call
+ <filename>gcc</filename> instead of using the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-CC'><filename>CC</filename></ulink>
+ variable.
+ Usually, in a cross-compilation environment,
+ <filename>gcc</filename> is the compiler for the build host
+ and the cross-compiler is named something similar to
+ <filename>arm-poky-linux-gnueabi-gcc</filename> and might
+ require arguments (e.g. to point to the associated sysroot
+ for the target machine).
+ </para>
+
+ <para>
+ When writing a recipe for Makefile-only software, keep the
+ following in mind:
+ <itemizedlist>
+ <listitem><para>
+ You probably need to patch the Makefile to use
+ variables instead of hardcoding tools within the
+ toolchain such as <filename>gcc</filename> and
+ <filename>g++</filename>.
+ </para></listitem>
+ <listitem><para>
+ The environment in which Make runs is set up with
+ various standard variables for compilation (e.g.
+ <filename>CC</filename>, <filename>CXX</filename>, and
+ so forth) in a similar manner to the environment set
+ up by the SDK's environment setup script.
+ One easy way to see these variables is to run the
+ <filename>devtool build</filename> command on the
+ recipe and then look in
+ <filename>oe-logs/run.do_compile</filename>.
+ Towards the top of this file, a list of environment
+ variables exists that are being set.
+ You can take advantage of these variables within the
+ Makefile.
+ </para></listitem>
+ <listitem><para>
+ If the Makefile sets a default for a variable using "=",
+ that default overrides the value set in the environment,
+ which is usually not desirable.
+ For this case, you can either patch the Makefile
+ so it sets the default using the "?=" operator, or
+ you can alternatively force the value on the
+ <filename>make</filename> command line.
+ To force the value on the command line, add the
+ variable setting to
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OEMAKE'><filename>EXTRA_OEMAKE</filename></ulink>
+ or
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG_CONFARGS'><filename>PACKAGECONFIG_CONFARGS</filename></ulink>
+ within the recipe.
+ Here is an example using <filename>EXTRA_OEMAKE</filename>:
+ <literallayout class='monospaced'>
+ EXTRA_OEMAKE += "'CC=${CC}' 'CXX=${CXX}'"
+ </literallayout>
+ In the above example, single quotes are used around the
+ variable settings as the values are likely to contain
+ spaces because required default options are passed to
+ the compiler.
+ </para></listitem>
+ <listitem><para>
+ Hardcoding paths inside Makefiles is often problematic
+ in a cross-compilation environment.
+ This is particularly true because those hardcoded paths
+ often point to locations on the build host and thus
+ will either be read-only or will introduce
+ contamination into the cross-compilation because they
+ are specific to the build host rather than the target.
+ Patching the Makefile to use prefix variables or other
+ path variables is usually the way to handle this
+ situation.
+ </para></listitem>
+ <listitem><para>
+ Sometimes a Makefile runs target-specific commands such
+ as <filename>ldconfig</filename>.
+ For such cases, you might be able to apply patches that
+ remove these commands from the Makefile.
+ </para></listitem>
+ </itemizedlist>
+ </para>
+ </section>
+
+ <section id='sdk-adding-native-tools'>
+ <title>Adding Native Tools</title>
+
+ <para>
+ Often, you need to build additional tools that run on the
+ <ulink url='&YOCTO_DOCS_REF_URL;#hardware-build-system-term'>build host</ulink>
+ as opposed to the target.
+ You should indicate this requirement by using one of the
+ following methods when you run
+ <filename>devtool add</filename>:
+ <itemizedlist>
+ <listitem><para>
+ Specify the name of the recipe such that it ends
+ with "-native".
+ Specifying the name like this produces a recipe that
+ only builds for the build host.
+ </para></listitem>
+ <listitem><para>
+ Specify the "‐‐also-native" option with the
+ <filename>devtool add</filename> command.
+ Specifying this option creates a recipe file that still
+ builds for the target but also creates a variant with
+ a "-native" suffix that builds for the build host.
+ </para></listitem>
+ </itemizedlist>
+ <note>
+ If you need to add a tool that is shipped as part of a
+ source tree that builds code for the target, you can
+ typically accomplish this by building the native and target
+ parts separately rather than within the same compilation
+ process.
+ Realize though that with the "‐‐also-native"
+ option, you can add the tool using just one recipe file.
+ </note>
+ </para>
+ </section>
+
+ <section id='sdk-adding-node-js-modules'>
+ <title>Adding Node.js Modules</title>
+
+ <para>
+ You can use the <filename>devtool add</filename> command two
+ different ways to add Node.js modules: 1) Through
+ <filename>npm</filename> and, 2) from a repository or local
+ source.
+ </para>
+
+ <para>
+ Use the following form to add Node.js modules through
+ <filename>npm</filename>:
+ <literallayout class='monospaced'>
+ $ devtool add "npm://registry.npmjs.org;name=forever;version=0.15.1"
+ </literallayout>
+ The name and version parameters are mandatory.
+ Lockdown and shrinkwrap files are generated and pointed to by
+ the recipe in order to freeze the version that is fetched for
+ the dependencies according to the first time.
+ This also saves checksums that are verified on future fetches.
+ Together, these behaviors ensure the reproducibility and
+ integrity of the build.
+ <note><title>Notes</title>
+ <itemizedlist>
+ <listitem><para>
+ You must use quotes around the URL.
+ The <filename>devtool add</filename> does not require
+ the quotes, but the shell considers ";" as a splitter
+ between multiple commands.
+ Thus, without the quotes,
+ <filename>devtool add</filename> does not receive the
+ other parts, which results in several "command not
+ found" errors.
+ </para></listitem>
+ <listitem><para>
+ In order to support adding Node.js modules, a
+ <filename>nodejs</filename> recipe must be part
+ of your SDK.
+ </para></listitem>
+ </itemizedlist>
+ </note>
+ </para>
+
+ <para>
+ As mentioned earlier, you can also add Node.js modules
+ directly from a repository or local source tree.
+ To add modules this way, use <filename>devtool add</filename>
+ in the following form:
+ <literallayout class='monospaced'>
+ $ devtool add https://github.com/diversario/node-ssdp
+ </literallayout>
+ In this example, <filename>devtool</filename> fetches the
+ specified Git repository, detects the code as Node.js
+ code, fetches dependencies using <filename>npm</filename>, and
+ sets
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink>
+ accordingly.
+ </para>
+ </section>
+ </section>
+
+ <section id='sdk-working-with-recipes'>
+ <title>Working With Recipes</title>
+
+ <para>
+ When building a recipe using the
+ <filename>devtool build</filename> command, the typical build
+ progresses as follows:
+ <orderedlist>
+ <listitem><para>
+ Fetch the source
+ </para></listitem>
+ <listitem><para>
+ Unpack the source
+ </para></listitem>
+ <listitem><para>
+ Configure the source
+ </para></listitem>
+ <listitem><para>
+ Compile the source
+ </para></listitem>
+ <listitem><para>
+ Install the build output
+ </para></listitem>
+ <listitem><para>
+ Package the installed output
+ </para></listitem>
+ </orderedlist>
+ For recipes in the workspace, fetching and unpacking is disabled
+ as the source tree has already been prepared and is persistent.
+ Each of these build steps is defined as a function (task), usually
+ with a "do_" prefix (e.g.
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-fetch'><filename>do_fetch</filename></ulink>,
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-unpack'><filename>do_unpack</filename></ulink>,
+ and so forth).
+ These functions are typically shell scripts but can instead be
+ written in Python.
+ </para>
+
+ <para>
+ If you look at the contents of a recipe, you will see that the
+ recipe does not include complete instructions for building the
+ software.
+ Instead, common functionality is encapsulated in classes inherited
+ with the <filename>inherit</filename> directive.
+ This technique leaves the recipe to describe just the things that
+ are specific to the software being built.
+ A
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-base'><filename>base</filename></ulink>
+ class exists that is implicitly inherited by all recipes and
+ provides the functionality that most recipes typically need.
+ </para>
+
+ <para>
+ The remainder of this section presents information useful when
+ working with recipes.
+ </para>
+
+ <section id='sdk-finding-logs-and-work-files'>
+ <title>Finding Logs and Work Files</title>
+
+ <para>
+ After the first run of the <filename>devtool build</filename>
+ command, recipes that were previously created using the
+ <filename>devtool add</filename> command or whose sources were
+ modified using the <filename>devtool modify</filename>
+ command contain symbolic links created within the source tree:
+ <itemizedlist>
+ <listitem><para>
+ <filename>oe-logs</filename>:
+ This link points to the directory in which log files
+ and run scripts for each build step are created.
+ </para></listitem>
+ <listitem><para>
+ <filename>oe-workdir</filename>:
+ This link points to the temporary work area for the
+ recipe.
+ The following locations under
+ <filename>oe-workdir</filename> are particularly
+ useful:
+ <itemizedlist>
+ <listitem><para>
+ <filename>image/</filename>:
+ Contains all of the files installed during
+ the
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+ stage.
+ Within a recipe, this directory is referred
+ to by the expression
+ <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>.
+ </para></listitem>
+ <listitem><para>
+ <filename>sysroot-destdir/</filename>:
+ Contains a subset of files installed within
+ <filename>do_install</filename> that have
+ been put into the shared sysroot.
+ For more information, see the
+ "<link linkend='sdk-sharing-files-between-recipes'>Sharing Files Between Recipes</link>"
+ section.
+ </para></listitem>
+ <listitem><para>
+ <filename>packages-split/</filename>:
+ Contains subdirectories for each package
+ produced by the recipe.
+ For more information, see the
+ "<link linkend='sdk-packaging'>Packaging</link>"
+ section.
+ </para></listitem>
+ </itemizedlist>
+ </para></listitem>
+ </itemizedlist>
+ You can use these links to get more information on what is
+ happening at each build step.
+ </para>
+ </section>
+
+ <section id='sdk-setting-configure-arguments'>
+ <title>Setting Configure Arguments</title>
+
+ <para>
+ If the software your recipe is building uses GNU autoconf,
+ then a fixed set of arguments is passed to it to enable
+ cross-compilation plus any extras specified by
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECONF'><filename>EXTRA_OECONF</filename></ulink>
+ or
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG_CONFARGS'><filename>PACKAGECONFIG_CONFARGS</filename></ulink>
+ set within the recipe.
+ If you wish to pass additional options, add them to
+ <filename>EXTRA_OECONF</filename> or
+ <filename>PACKAGECONFIG_CONFARGS</filename>.
+ Other supported build tools have similar variables
+ (e.g.
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECMAKE'><filename>EXTRA_OECMAKE</filename></ulink>
+ for CMake,
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OESCONS'><filename>EXTRA_OESCONS</filename></ulink>
+ for Scons, and so forth).
+ If you need to pass anything on the <filename>make</filename>
+ command line, you can use <filename>EXTRA_OEMAKE</filename> or the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGECONFIG_CONFARGS'><filename>PACKAGECONFIG_CONFARGS</filename></ulink>
+ variables to do so.
+ </para>
+
+ <para>
+ You can use the <filename>devtool configure-help</filename> command
+ to help you set the arguments listed in the previous paragraph.
+ The command determines the exact options being passed, and shows
+ them to you along with any custom arguments specified through
+ <filename>EXTRA_OECONF</filename> or
+ <filename>PACKAGECONFIG_CONFARGS</filename>.
+ If applicable, the command also shows you the output of the
+ configure script's "‐‐help" option as a reference.
+ </para>
+ </section>
+
+ <section id='sdk-sharing-files-between-recipes'>
+ <title>Sharing Files Between Recipes</title>
+
+ <para>
+ Recipes often need to use files provided by other recipes on
+ the
+ <ulink url='&YOCTO_DOCS_REF_URL;#hardware-build-system-term'>build host</ulink>.
+ For example, an application linking to a common library needs
+ access to the library itself and its associated headers.
+ The way this access is accomplished within the extensible SDK is
+ through the sysroot.
+ One sysroot exists per "machine" for which the SDK is being
+ built.
+ In practical terms, this means a sysroot exists for the target
+ machine, and a sysroot exists for the build host.
+ </para>
+
+ <para>
+ Recipes should never write files directly into the sysroot.
+ Instead, files should be installed into standard locations
+ during the
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+ task within the
+ <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>
+ directory.
+ A subset of these files automatically goes into the sysroot.
+ The reason for this limitation is that almost all files that go
+ into the sysroot are cataloged in manifests in order to ensure
+ they can be removed later when a recipe is modified or removed.
+ Thus, the sysroot is able to remain free from stale files.
+ </para>
+ </section>
+
+ <section id='sdk-packaging'>
+ <title>Packaging</title>
+
+ <para>
+ Packaging is not always particularly relevant within the
+ extensible SDK.
+ However, if you examine how build output gets into the final image
+ on the target device, it is important to understand packaging
+ because the contents of the image are expressed in terms of
+ packages and not recipes.
+ </para>
+
+ <para>
+ During the
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
+ task, files installed during the
+ <ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
+ task are split into one main package, which is almost always
+ named the same as the recipe, and into several other packages.
+ This separation exists because not all of those installed files
+ are useful in every image.
+ For example, you probably do not need any of the documentation
+ installed in a production image.
+ Consequently, for each recipe the documentation files are
+ separated into a <filename>-doc</filename> package.
+ Recipes that package software containing optional modules or
+ plugins might undergo additional package splitting as well.
+ </para>
+
+ <para>
+ After building a recipe, you can see where files have gone by
+ looking in the <filename>oe-workdir/packages-split</filename>
+ directory, which contains a subdirectory for each package.
+ Apart from some advanced cases, the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>
+ and
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>
+ variables controls splitting.
+ The <filename>PACKAGES</filename> variable lists all of the
+ packages to be produced, while the <filename>FILES</filename>
+ variable specifies which files to include in each package by
+ using an override to specify the package.
+ For example, <filename>FILES_${PN}</filename> specifies the
+ files to go into the main package (i.e. the main package has
+ the same name as the recipe and
+ <filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
+ evaluates to the recipe name).
+ The order of the <filename>PACKAGES</filename> value is
+ significant.
+ For each installed file, the first package whose
+ <filename>FILES</filename> value matches the file is the
+ package into which the file goes.
+ Defaults exist for both the <filename>PACKAGES</filename> and
+ <filename>FILES</filename> variables.
+ Consequently, you might find you do not even need to set these
+ variables in your recipe unless the software the recipe is
+ building installs files into non-standard locations.
+ </para>
+ </section>
+ </section>
+
+ <section id='sdk-restoring-the-target-device-to-its-original-state'>
+ <title>Restoring the Target Device to its Original State</title>
+
+ <para>
+ If you use the <filename>devtool deploy-target</filename>
+ command to write a recipe's build output to the target, and
+ you are working on an existing component of the system, then you
+ might find yourself in a situation where you need to restore the
+ original files that existed prior to running the
+ <filename>devtool deploy-target</filename> command.
+ Because the <filename>devtool deploy-target</filename> command
+ backs up any files it overwrites, you can use the
+ <filename>devtool undeploy-target</filename> command to restore
+ those files and remove any other files the recipe deployed.
+ Consider the following example:
+ <literallayout class='monospaced'>
+ $ devtool undeploy-target lighttpd root@192.168.7.2
+ </literallayout>
+ If you have deployed multiple applications, you can remove them
+ all using the "-a" option thus restoring the target device to its
+ original state:
+ <literallayout class='monospaced'>
+ $ devtool undeploy-target -a root@192.168.7.2
+ </literallayout>
+ Information about files deployed to the target as well as any
+ backed up files are stored on the target itself.
+ This storage, of course, requires some additional space
+ on the target machine.
+ <note>
+ The <filename>devtool deploy-target</filename> and
+ <filename>devtool undeploy-target</filename> commands do not
+ currently interact with any package management system on the
+ target device (e.g. RPM or OPKG).
+ Consequently, you should not intermingle
+ <filename>devtool deploy-target</filename> and package
+ manager operations on the target device.
+ Doing so could result in a conflicting set of files.
+ </note>
+ </para>
+ </section>
+
+ <section id='sdk-installing-additional-items-into-the-extensible-sdk'>
+ <title>Installing Additional Items Into the Extensible SDK</title>
+
+ <para>
+ Out of the box the extensible SDK typically only comes with a small
+ number of tools and libraries.
+ A minimal SDK starts mostly empty and is populated on-demand.
+ Sometimes you must explicitly install extra items into the SDK.
+ If you need these extra items, you can first search for the items
+ using the <filename>devtool search</filename> command.
+ For example, suppose you need to link to libGL but you are not sure
+ which recipe provides libGL.
+ You can use the following command to find out:
+ <literallayout class='monospaced'>
+ $ devtool search libGL
+ mesa A free implementation of the OpenGL API
+ </literallayout>
+ Once you know the recipe (i.e. <filename>mesa</filename> in this
+ example), you can install it:
+ <literallayout class='monospaced'>
+ $ devtool sdk-install mesa
+ </literallayout>
+ By default, the <filename>devtool sdk-install</filename> command
+ assumes the item is available in pre-built form from your SDK
+ provider.
+ If the item is not available and it is acceptable to build the item
+ from source, you can add the "-s" option as follows:
+ <literallayout class='monospaced'>
+ $ devtool sdk-install -s mesa
+ </literallayout>
+ It is important to remember that building the item from source
+ takes significantly longer than installing the pre-built artifact.
+ Also, if no recipe exists for the item you want to add to the SDK,
+ you must instead add the item using the
+ <filename>devtool add</filename> command.
+ </para>
+ </section>
+
+ <section id='sdk-applying-updates-to-an-installed-extensible-sdk'>
+ <title>Applying Updates to an Installed Extensible SDK</title>
+
+ <para>
+ If you are working with an installed extensible SDK that gets
+ occasionally updated (e.g. a third-party SDK), then you will need
+ to manually "pull down" the updates into the installed SDK.
+ </para>
+
+ <para>
+ To update your installed SDK, use <filename>devtool</filename> as
+ follows:
+ <literallayout class='monospaced'>
+ $ devtool sdk-update
+ </literallayout>
+ The previous command assumes your SDK provider has set the default
+ update URL for you through the
+ <ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_UPDATE_URL'><filename>SDK_UPDATE_URL</filename></ulink>
+ variable as described in the
+ "<link linkend='sdk-providing-updates-to-the-extensible-sdk-after-installation'>Providing Updates to the Extensible SDK After Installation</link>"
+ section.
+ If the SDK provider has not set that default URL, you need to
+ specify it yourself in the command as follows:
+ <literallayout class='monospaced'>
+ $ devtool sdk-update <replaceable>path_to_update_directory</replaceable>
+ </literallayout>
+ <note>
+ The URL needs to point specifically to a published SDK and
+ not to an SDK installer that you would download and install.
+ </note>
+ </para>
+ </section>
+
+ <section id='sdk-creating-a-derivative-sdk-with-additional-components'>
+ <title>Creating a Derivative SDK With Additional Components</title>
+
+ <para>
+ You might need to produce an SDK that contains your own custom
+ libraries.
+ A good example would be if you were a vendor with customers that
+ use your SDK to build their own platform-specific software and
+ those customers need an SDK that has custom libraries.
+ In such a case, you can produce a derivative SDK based on the
+ currently installed SDK fairly easily by following these steps:
+ <orderedlist>
+ <listitem><para>
+ If necessary, install an extensible SDK that
+ you want to use as a base for your derivative SDK.
+ </para></listitem>
+ <listitem><para>
+ Source the environment script for the SDK.
+ </para></listitem>
+ <listitem><para>
+ Add the extra libraries or other components you want by
+ using the <filename>devtool add</filename> command.
+ </para></listitem>
+ <listitem><para>
+ Run the <filename>devtool build-sdk</filename> command.
+ </para></listitem>
+ </orderedlist>
+ The previous steps take the recipes added to the workspace and
+ construct a new SDK installer that contains those recipes and the
+ resulting binary artifacts.
+ The recipes go into their own separate layer in the constructed
+ derivative SDK, which leaves the workspace clean and ready for
+ users to add their own recipes.
+ </para>
+ </section>
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->