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diff --git a/yocto-poky/documentation/sdk-manual/sdk-extensible.xml b/yocto-poky/documentation/sdk-manual/sdk-extensible.xml deleted file mode 100644 index 3e11fc97d..000000000 --- a/yocto-poky/documentation/sdk-manual/sdk-extensible.xml +++ /dev/null @@ -1,1304 +0,0 @@ -<!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='sdk-extensible'> - -<title>Using the Extensible SDK</title> - -<para> - This chapter describes the extensible SDK and how to use it. - 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_DEV_URL;#build-system-term'>OpenEmbedded build system</ulink>. -</para> - -<para> - Information in this chapter covers features that are not part of the - standard SDK. - In other words, the chapter presents information unique to the - extensible SDK only. - For information on how to use the standard SDK, see the - "<link linkend='sdk-using-the-standard-sdk'>Using the Standard SDK</link>" - chapter. -</para> - -<section id='sdk-setting-up-to-use-the-extensible-sdk'> - <title>Setting Up to Use the Extensible SDK</title> - - <para> - Getting set up to use the extensible SDK is identical to getting set - up to use the standard SDK. - You still need to locate and run the installer and then run the - environment setup script. - See the - "<link linkend='sdk-installing-the-sdk'>Installing the SDK</link>" - and the - "<link linkend='sdk-running-the-sdk-environment-setup-script'>Running the SDK Environment Setup Script</link>" - sections for general information. - The following items highlight the only differences between getting - set up to use the extensible SDK as compared to the standard SDK: - <itemizedlist> - <listitem><para><emphasis>Default Installation Directory:</emphasis> - By default, the extensible SDK installs into the - <filename>poky_sdk</filename> folder of your home directory. - As with the standard SDK, you can choose to install the - extensible SDK in any location when you run the installer. - However, unlike the standard SDK, the location you choose needs - to be writable for whichever users need to use the SDK, - since files will need to be written under that directory during - the normal course of operation. - </para></listitem> - <listitem><para><emphasis>Build Tools and Build System:</emphasis> - The extensible SDK installer performs additional tasks as - compared to the standard SDK installer. - The extensible SDK installer extracts build tools specific - to the SDK and the installer also prepares the internal build - system within the SDK. - Here is example output for running the extensible SDK - installer: - <literallayout class='monospaced'> - $ ./poky-glibc-x86_64-core-image-minimal-core2-64-toolchain-ext-2.1+snapshot.sh - Poky (Yocto Project Reference Distro) Extensible SDK installer version 2.1+snapshot - =================================================================================== - 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... - 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></listitem> - </itemizedlist> - </para> - - <para> - After installing the SDK, you need to run the SDK environment setup - script. - Here is the output: - <literallayout class='monospaced'> - $ 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> - Once you run the environment setup script, you have - <filename>devtool</filename> available. - </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. - </para> - - <para> - The <filename>devtool</filename> command line is organized similarly - to - <ulink url='&YOCTO_DOCS_DEV_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. - </para> - - <para> - Two <filename>devtool</filename> subcommands that provide - entry-points into development are: - <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> - </itemizedlist> - As with the OpenEmbedded 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, both 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> and - <filename>devtool modify</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_DEV_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 where other developers are responsible for - various areas of source code. - As a developer, you are probably interested in using - that source code as part of your development using - 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 represents a common situation - where the source code does not exist locally - and needs to be extracted. - In this situation, you just let it get - extracted to the default workspace - you do not - want it 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> - creates a recipe and an append file in the - workspace as well as extracts the upstream - source files into a local Git repository also - within the <filename>sources</filename> folder. - </para></listitem> - <listitem><para><emphasis>Middle</emphasis>: - The middle scenario 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. - As always, if required <filename>devtool</filename> creates - a Git repository locally during the extraction. - 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: - <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 both the recipe and an append file - for the recipe. - </para></listitem> - <listitem><para><emphasis>Right</emphasis>: - The right scenario represents a situation - where the source tree (srctree) has been - previously prepared outside of the - <filename>devtool</filename> workspace. - </para> - - <para>The following command names the recipe - and identifies where the existing source tree - is located: - <literallayout class='monospaced'> - $ devtool add <replaceable>recipe srctree</replaceable> - </literallayout> - The command examines the source code and creates - a recipe for it placing the recipe into the - workspace.</para> - - <para>Because the extracted source code already exists, - <filename>devtool</filename> does not try to - relocate it into the workspace - just the new - the recipe is placed in the workspace.</para> - - <para>Aside from a recipe folder, the command - also creates an append folder and places an initial - <filename>*.bbappend</filename> within. - </para></listitem> - </itemizedlist> - </para></listitem> - <listitem><para><emphasis>Edit the Recipe</emphasis>: - At this point, 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>: - At this point in the flow, the next step you - take depends on what you are going to do with - the new code.</para> - <para>If you need to take the build output and eventually - move it to the target hardware, you would use - <filename>devtool build</filename>: - <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 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, 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>Optionally Update the Recipe With Patch Files</emphasis>: - Once you are satisfied with the recipe, if you have made - any changes to the source tree that you want to have - applied by the recipe, you need to generate patches - from those changes. - You do this before moving the recipe - to its final layer and cleaning up the workspace area - <filename>devtool</filename> uses. - This optional step is especially relevant if you are - using or adding third-party software.</para> - <para>To convert commits created using Git to patch files, - use the <filename>devtool update-recipe</filename> command. - <note> - Any changes you want to turn into patches must be - committed to the Git repository in the source tree. - </note> - <literallayout class='monospaced'> - $ devtool update-recipe <replaceable>recipe</replaceable> - </literallayout> - </para></listitem> - <listitem><para><emphasis>Move the Recipe to its Permanent Layer</emphasis>: - Before cleaning up the workspace, you need to move the - final recipe to its permanent layer. - You must do this before using the - <filename>devtool reset</filename> command if you want to - retain the recipe. - </para></listitem> - <listitem><para><emphasis>Reset the Recipe</emphasis>: - As a final step, you can restore the state such that - standard layers and the upstream source is used to build - the recipe rather than data in the workspace. - To reset the recipe, use the <filename>devtool reset</filename> - command: - <literallayout class='monospaced'> - $ devtool reset <replaceable>recipe</replaceable> - </literallayout> - </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 recipe in - place. - The command is flexible enough to allow you to extract code, - 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 - you would use with 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 in some layer external - to the <filename>devtool</filename> workspace. - </para></listitem> - <listitem><para>The source files exist 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 some 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 represents a common situation - where the source code does not exist locally - and needs to be extracted. - In this situation, the source is extracted - into the default 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, - it uses the - <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink> - variable to locate the source code and - any local patch files from other developers are - located. - <note> - You cannot provide an URL for - <replaceable>srctree</replaceable> when using the - <filename>devtool modify</filename> command. - </note> - With this scenario, however, since no - <replaceable>srctree</replaceable> argument exists, the - <filename>devtool modify</filename> command by default - extracts the source files to a Git structure. - Furthermore, the location for the extracted source is the - default area within the workspace. - The result is that the command sets up both the source - code and an append file within the workspace with the - recipe remaining in its original location. - </para></listitem> - <listitem><para><emphasis>Middle</emphasis>: - The middle scenario 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 in its own - layer outside the workspace.</para> - - <para>The following command tells - <filename>devtool</filename> what recipe with - which to work and, in this case, identifies a local - area for the extracted source files that is outside - of the default workspace: - <literallayout class='monospaced'> - $ devtool modify <replaceable>recipe srctree</replaceable> - </literallayout> - As with all extractions, the command uses - the recipe's <filename>SRC_URI</filename> to locate the - source files. - Once the files are located, the command by default - extracts them. - Providing the <replaceable>srctree</replaceable> - argument instructs <filename>devtool</filename> where - place the extracted source.</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 - provided with <replaceable>srctree</replaceable>. - </para></listitem> - <listitem><para><emphasis>Right</emphasis>: - The right scenario represents a situation - where the source tree - (<replaceable>srctree</replaceable>) exists as a - previously extracted Git structure outside of - the <filename>devtool</filename> workspace. - In this example, the recipe also exists - elsewhere 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>Once the command finishes, it creates only - an append file for the recipe in the 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</emphasis>: - Once you have updated the source files, you can build - the recipe. - </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, 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>Optionally Create Patch Files for Your Changes</emphasis>: - After you have debugged your changes, you can - use <filename>devtool update-recipe</filename> to - generate patch files for all the commits you have - made. - <note> - Patch files are generated only for changes - you have committed. - </note> - <literallayout class='monospaced'> - $ devtool update-recipe <replaceable>recipe</replaceable> - </literallayout> - By default, the - <filename>devtool update-recipe</filename> command - creates the patch files in a folder named the same - as the recipe beneath the folder in which the recipe - resides, and updates the recipe's - <ulink url='&YOCTO_DOCS_REF_URL;#var-SRC_URI'><filename>SRC_URI</filename></ulink> - statement to point to the generated patch files. - <note> - You can use the - "--append <replaceable>LAYERDIR</replaceable>" - option to cause the command to create append files - in a specific layer rather than the default - recipe layer. - </note> - </para></listitem> - <listitem><para><emphasis>Restore the Workspace</emphasis>: - The <filename>devtool reset</filename> restores the - state so that standard layers and upstream sources are - used to build the recipe rather than what is in the - workspace. - <literallayout class='monospaced'> - $ devtool reset <replaceable>recipe</replaceable> - </literallayout> - </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 with which you provide it. - 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 through - <filename>npm</filename> - </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 you can build the recipe. - Once the recipe can be built, 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> attempts to determine - the name and version of the software being built from - various metadata within the source tree. - Furthermore, the command sets the name of the created recipe - file accordingly. - If the name or version cannot be determined, the - <filename>devtool add</filename> command prints an error and - you must re-run the command with both the name and version - or just the name or version specified. - </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 in the - <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink> - value within the recipe. - If a dependency cannot be mapped, then a comment is placed in - the recipe indicating such. - The inability to map a dependency might be caused because the - naming is not 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 to satisfy the dependency and then come - back to the first recipe and add its name to - <filename>DEPENDS</filename>. - </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} += "dependency1 dependency2 ..." - </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 for an option to disable 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 and sets the - <ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink> - value accordingly. - You should double-check this value against the documentation - or source files for the software you are building and update - that <filename>LICENSE</filename> value if necessary. - </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. - However, license statements often appear in comments at the top - of source files or within documentation. - 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, the - <filename>LICENSE</filename> value is set to "CLOSED" and the - <filename>LIC_FILES_CHKSUM</filename> vaule remains unset. - This behavior allows you to continue with development but is - unlikely to be correct in all cases. - Consequently, 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 <filename>make</filename> 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 - <filename>CC</filename> 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 some 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 <filename>make</filename> 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 you will see a list of - environment variables 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. - In this situation, 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> - within the recipe as follows: - <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 by virtue of - being 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. - </para></listitem> - <listitem><para> - Sometimes a Makefile runs target-specific commands such - as <filename>ldconfig</filename>. - For such cases, you might be able to simply 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 - build host system as opposed to the target. - You should indicate this 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 in the - following form to add Node.js modules: - <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 in order to provide Node.js - itself. - </para></listitem> - </itemizedlist> - </note> - </para> - </section> -</section> - -<section id='sdk-working-with-recipes'> - <title>Working With Recipes</title> - - <para> - When building a recipe with <filename>devtool build</filename> the - typical build progression is 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> - Compiling 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, usually with a - "do_" prefix. - 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, leaving the recipe - to describe just the things that are specific to the software to be - built. - A <ulink url='ref-classes-base'><filename>base</filename></ulink> - class exists that is implicitly inherited by all recipes and provides - the functionality that most typical recipes 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> - When you are debugging a recipe that you previously created using - <filename>devtool add</filename> or whose source you are modifying - by using the <filename>devtool modify</filename> command, after - the first run of <filename>devtool build</filename>, you will - find some symbolic links created within the source tree: - <filename>oe-logs</filename>, which points to the directory in - which log files and run scripts for each build step are created - and <filename>oe-workdir</filename>, which points to the temporary - work area for the recipe. - You can use these links to get more information on what is - happening at each build step. - </para> - - <para> - These locations under <filename>oe-workdir</filename> are - particularly useful: - <itemizedlist> - <listitem><para><filename>image/</filename>: - Contains all of the files installed at 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> - </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> - set within the recipe. - If you wish to pass additional options, add them to - <filename>EXTRA_OECONF</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> 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>. - 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 build host. - 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 go 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 several other packages. - This separation is done because not all of those installed files - are always 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 that has optional modules or - plugins might do 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, - using an override to specify the package. - For example, <filename>FILES_${PN}</filename> specifies the files - to go into the main package (i.e. the main package is named the - same as the recipe and - <filename>${</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> 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 at once thus restoring the target device back 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> command do not - currently interact with any package management system on the - target device (e.g. RPM or OPKG). - Consequently, you should not intermingle operations - <filename>devtool deploy-target</filename> and the 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> - The extensible SDK typically only comes with a small number of tools - and libraries out of the box. - If you have a minimal SDK, then it starts mostly empty and is - populated on-demand. - However, sometimes you will need to 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 it. - 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> 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 it using the <filename>devtool add</filename> command. - </para> -</section> - -<section id='sdk-updating-the-extensible-sdk'> - <title>Updating the Extensible SDK</title> - - <para> - If you are working with an extensible SDK that gets occasionally - updated (e.g. typically when that SDK has been provided to you by - another party), then you will need to manually pull down those - updates to your installed SDK. - </para> - - <para> - To update your installed SDK, run the following: - <literallayout class='monospaced'> - $ devtool sdk-update - </literallayout> - The previous command assumes your SDK provider has set the default - update URL for you. - If that URL has not been set, you need to specify it yourself 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 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 for sending to a third party (e.g., if you are a vendor with - customers needing to build their own software for the target platform). - If that is the case, then you can produce a derivative SDK based on - the currently installed SDK fairly easily. - Use 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 above procedure takes the recipes added to the workspace and - constructs a new SDK installer containing those recipes and the - resulting binary artifacts. - The recipes go into their own separate layer in the constructed - derivative SDK, leaving the workspace clean and ready for users - to add their own recipes. - </para> -</section> - -</chapter> -<!-- -vim: expandtab tw=80 ts=4 ---> |