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| author | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2012-07-17 19:42:40 +0200 |
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| committer | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2012-07-17 19:42:40 +0200 |
| commit | d56422a51af9e4c87aac365830f598fca6ca8a29 (patch) | |
| tree | 0c475a5a18a9cf1d62e4504e6962c1d047b7ba6b /docs | |
| parent | c6580011f12e6ca8f7eb87af11d4e9d6def4316f (diff) | |
| download | buildroot-novena-d56422a51af9e4c87aac365830f598fca6ca8a29.tar.gz buildroot-novena-d56422a51af9e4c87aac365830f598fca6ca8a29.zip | |
doc: get rid of the old HTML-only documentation
Users keep falling on this documentation, which is no longer kept
up-to-date with the developments. Get rid of it now.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/buildroot.html | 1834 |
1 files changed, 0 insertions, 1834 deletions
diff --git a/docs/buildroot.html b/docs/buildroot.html deleted file mode 100644 index d178df1f5..000000000 --- a/docs/buildroot.html +++ /dev/null @@ -1,1834 +0,0 @@ -<!DOCTYPE html> -<html lang="en"> - -<head> - <title>Buildroot - Usage and documentation</title> - <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> - <link rel="stylesheet" href="stylesheet.css"> -</head> - -<body> - <div class="main"> - <div class="titre"> - <h1>Buildroot</h1> - </div> - - <p><a href="http://buildroot.net/">Buildroot</a> usage and documentation - by Thomas Petazzoni. Contributions from Karsten Kruse, Ned Ludd, Martin - Herren and others.</p> - - <ul> - <li><a href="#about">About Buildroot</a></li> - <li><a href="#download">Obtaining Buildroot</a></li> - <li><a href="#using">Using Buildroot</a></li> - <li><a href="#custom_targetfs">Customizing the generated target filesystem</a></li> - <li><a href="#custom_busybox">Customizing the Busybox configuration</a></li> - <li><a href="#custom_uclibc">Customizing the uClibc configuration</a></li> - <li><a href="#custom_linux26">Customizing the Linux kernel configuration</a></li> - <li><a href="#rebuilding_packages">Understanding how to rebuild packages</a></li> - <li><a href="#buildroot_innards">How Buildroot works</a></li> - <li><a href="#using_toolchain">Using the uClibc toolchain outside Buildroot</a></li> - <li><a href="#external_toolchain">Use an external toolchain</a></li> - <li><a href="#ccache-support">Using <code>ccache</code> in Buildroot</li> - <li><a href="#downloaded_packages">Location of downloaded packages</a></li> - <li><a href="#add_packages">Adding new packages to Buildroot</a></li> - <li><a href="#board_support">Creating your own board support</a></li> - <li><a href="#faq">Frequently asked questions</a></li> - <li><a href="#links">Resources</a></li> - </ul> - - <p><b>WARNING:</b> Since the 2011.11 release, this page is on its way to be - deprecated. Information may be incomplete and out-dated.</p> - - <p>To get an up-to-date documentation for - <a href="http://buildroot.net/">Buildroot</a>-2011.11 or a git view, just - run:</p> -<pre> - $ make manual -</pre> - <p><i>This requires <code>asciidoc</code> installed on the host system.</i></p> - - <p>For releases since <a href="http://buildroot.net/">Buildroot</a>-2012.02, - manuals (html, pdf and text) are available in the <code>docs/manual</code> - directory.</p> - - <h2 id="about">About Buildroot</h2> - - <p>Buildroot is a set of Makefiles and patches that allows you to easily - generate a cross-compilation toolchain, a root filesystem and a Linux - kernel image for your target. Buildroot can be used for one, two or all - of these options, independently.</p> - - <p>Buildroot is useful mainly for people working with embedded systems. - Embedded systems often use processors that are not the regular x86 - processors everyone is used to having in his PC. They can be PowerPC - processors, MIPS processors, ARM processors, etc.</p> - - <p>A compilation toolchain is the set of tools that allows you to - compile code for your system. It consists of a compiler (in our case, - <code>gcc</code>), binary utils like assembler and linker (in our case, - <code>binutils</code>) and a C standard library (for example - <a href="http://www.gnu.org/software/libc/libc.html">GNU Libc</a>, - <a href="http://www.uclibc.org/">uClibc</a> or - <a href="http://www.fefe.de/dietlibc/">dietlibc</a>). The system installed - on your development station certainly already has a compilation - toolchain that you can use to compile an application that runs on your - system. If you're using a PC, your compilation toolchain runs on an x86 - processor and generates code for an x86 processor. Under most Linux - systems, the compilation toolchain uses the GNU libc (glibc) as the C - standard library. This compilation toolchain is called the "host - compilation toolchain". The machine on which it is running, and on - which you're working, is called the "host system". The - compilation toolchain is provided by your distribution, and Buildroot - has nothing to do with it (other than using it to build a - cross-compilation toolchain and other tools that are run on the - development host).</p> - - <p>As said above, the compilation toolchain that comes with your system - runs on and generates code for the processor in your host system. As - your embedded system has a different processor, you need a - cross-compilation toolchain — a compilation toolchain that runs on - your host system but generates code for your target system (and target - processor). For example, if your host system uses x86 and your target - system uses ARM, the regular compilation toolchain on your host runs on - x86 and generates code for x86, while the cross-compilation toolchain - runs on x86 and generates code for ARM.</p> - - <p>Even if your embedded system uses an x86 processor, you might be - interested in Buildroot for two reasons:</p> - - <ul> - <li>The compilation toolchain on your host certainly uses the GNU Libc - which is a complete but huge C standard library. Instead of using GNU - Libc on your target system, you can use uClibc which is a tiny C - standard library. If you want to use this C library, then you need a - compilation toolchain to generate binaries linked with it. Buildroot - can do that for you.</li> - - <li>Buildroot automates the building of a root filesystem with all needed - tools like busybox. That makes it much easier than doing it by hand.</li> - </ul> - - <p>You might wonder why such a tool is needed when you can compile - <code>gcc</code>, <code>binutils</code>, <code>uClibc</code> and all - the other tools by hand. Of course doing so is possible but, dealing with - all of the configure options and problems of every <code>gcc</code> or - <code>binutils</code> version is very time-consuming and uninteresting. - Buildroot automates this process through the use of Makefiles and has a - collection of patches for each <code>gcc</code> and <code>binutils</code> - version to make them work on most architectures.</p> - - <p>Moreover, Buildroot provides an infrastructure for reproducing - the build process of your kernel, cross-toolchain, and embedded root - filesystem. Being able to reproduce the build process will be useful when a - component needs to be patched or updated or when another person is supposed - to take over the project.</p> - - <h2 id="download">Obtaining Buildroot</h2> - - <p>Buildroot releases are made approximately every 3 - months. Direct Git access and daily snapshots are also - available, if you want more bleeding edge.</p> - - <p>Releases are available at - <a href="http://buildroot.net/downloads/">http://buildroot.net/downloads/</a>.</p> - - <p>The latest snapshot is always available at - <a href="http://buildroot.net/downloads/snapshots/buildroot-snapshot.tar.bz2">http://buildroot.net/downloads/snapshots/buildroot-snapshot.tar.bz2</a>, - and previous snapshots are also available at - <a href="http://buildroot.net/downloads/snapshots/">http://buildroot.net/downloads/snapshots/</a>.</p> - - <p>To download Buildroot using Git, you can simply follow - the rules described on the "Accessing Git" page - (<a href= "http://buildroot.net/git.html">http://buildroot.net/git.html</a>) - of the Buildroot website - (<a href="http://buildroot.net">http://buildroot.net</a>). - For the impatient, here's a quick recipe:</p> - -<pre> - $ git clone git://git.buildroot.net/buildroot -</pre> - - <h2 id="using">Using Buildroot</h2> - - <p>Buildroot has a nice configuration tool similar to the one you can find - in the Linux kernel - (<a href="http://www.kernel.org/">http://www.kernel.org/</a>) or in Busybox - (<a href="http://www.busybox.net/">http://www.busybox.net/</a>). Note that - you can (and should) build everything as a normal user. There is no need to - be root to configure and use Buildroot. The first step is to run the - configuration assistant:</p> - -<pre> - $ make menuconfig -</pre> - - <p>to run the curses-based configurator, or</p> - -<pre> - $ make xconfig -</pre> - - <p>or</p> - -<pre> - $ make gconfig -</pre> - - <p>to run the Qt or GTK-based configurators.</p> - - <p>All of these "make" commands will need to build a configuration - utility, so you may need to install "development" packages for relevant - libraries used by the configuration utilities. On Debian-like systems, - the <code>libncurses5-dev</code> package is required to use the <i> - menuconfig</i> interface, <code>libqt4-dev</code> is required to use - the <i>xconfig</i> interface, and <code>libglib2.0-dev, libgtk2.0-dev - and libglade2-dev</code> are needed to use the <i>gconfig</i> interface.</p> - - <p>For each menu entry in the configuration tool, you can find associated - help that describes the purpose of the entry.</p> - - <p>Once everything is configured, the configuration tool generates a - <code>.config</code> file that contains the description of your - configuration. It will be used by the Makefiles to do what's needed.</p> - - - <p>Let's go:</p> - -<pre> - $ make -</pre> - - <p>You <b>should never</b> use <code>make -jN</code> with - Buildroot: it does not support <i>top-level parallel - make</i>. Instead, use the <code>BR2_JLEVEL</code> option to tell - Buildroot to run each package compilation with <code>make - -jN</code>.</p> - - <p>This command will generally perform the following steps:</p> - <ul> - <li>Download source files (as required)</li> - <li>Configure, build and install the cross-compiling toolchain - if an internal toolchain is used, or import a toolchain if an - external toolchain is used</li> - <li>Build/install selected target packages</li> - <li>Build a kernel image, if selected</li> - <li>Build a bootloader image, if selected</li> - <li>Create a root filesystem in selected formats</li> - </ul> - - <p>Buildroot output is stored in a single directory, <code>output/</code>. - This directory contains several subdirectories:</p> - - <ul> - <li><code>images/</code> where all the images (kernel image, - bootloader and root filesystem images) are stored.</li> - - <li><code>build/</code> where all the components except for the - cross-compilation toolchain are built (this includes tools needed to - run Buildroot on the host and packages compiled for the target). The - <code>build/</code> directory contains one subdirectory for each of - these components.</li> - - <li><code>staging/</code> which contains a hierarchy similar to a root - filesystem hierarchy. This directory contains the installation of the - cross-compilation toolchain and all the userspace packages selected - for the target. However, this directory is <i>not</i> intended to be - the root filesystem for the target: it contains a lot of development - files, unstripped binaries and libraries that make it far too big for - an embedded system. These development files are used to compile - libraries and applications for the target that depend on other - libraries.</li> - - <li><code>target/</code> which contains <i>almost</i> the complete - root filesystem for the target: everything needed is present except - the device files in <code>/dev/</code> (Buildroot can't create them - because Buildroot doesn't run as root and doesn't want to run as - root). Therefore, this directory <b>should not be used on your target</b>. - Instead, you should use one of the images built in the - <code>images/</code> directory. If you need an extracted image of the - root filesystem for booting over NFS, then use the tarball image - generated in <code>images/</code> and extract it as root.<br/>Compared - to <code>staging/</code>, <code>target/</code> contains only the - files and libraries needed to run the selected target applications: - the development files (headers, etc.) are not present, unless the - <code>development files in target filesystem</code> option is selected. - </li> - - <li><code>host/</code> contains the installation of tools compiled for - the host that are needed for the proper execution of Buildroot, - including the cross-compilation toolchain.</li> - - <li><code>toolchain/</code> contains the build directories for the - various components of the cross-compilation toolchain.</li> - </ul> - - <h3 id="offline_builds">Offline builds</h3> - - <p>If you intend to do an offline build and just want to download - all sources that you previously selected in the configurator - (<i>menuconfig</i>, <i>xconfig</i> or <i>gconfig</i>), then issue:</p> - -<pre> - $ make source -</pre> - - <p>You can now disconnect or copy the content of your <code>dl</code> - directory to the build-host.</p> - - <h3 id="building_out_of_tree">Building out-of-tree</h3> - - <p>Buildroot supports building out of tree with a syntax similar to the - Linux kernel. To use it, add O=<directory> to the make command - line:</p> - -<pre> - $ make O=/tmp/build -</pre> - - <p>Or:</p> - -<pre> - $ cd /tmp/build; make O=$PWD -C path/to/buildroot -</pre> - - <p>All the output files will be located under <code>/tmp/build</code>.</p> - - <p>When using out-of-tree builds, the Buildroot <code>.config</code> and - temporary files are also stored in the output directory. This means that - you can safely run multiple builds in parallel using the same source - tree as long as they use unique output directories.</p> - - <p>For ease of use, Buildroot generates a Makefile wrapper in the output - directory - So after the first run, you no longer need to pass - <code>O=..</code> and <code>-C ..</code>, simply run (in the output - directory):</p> - -<pre> - $ make <target> -</pre> - - <h3 id="environment_variables">Environment variables</h3> - - <p>Buildroot also honors some environment variables, when they are passed - to <code>make</code> or set in the environment:</p> - <ul> - <li><code>HOSTCXX</code>, the host C++ compiler to use</li> - <li><code>HOSTCC</code>, the host C compiler to use</li> - <li><code>UCLIBC_CONFIG_FILE=<path/to/.config></code>, path to - the uClibc configuration file, used to compile uClibc, if an - internal toolchain is being built</li> - <li><code>BUSYBOX_CONFIG_FILE=<path/to/.config></code>, path to - the Busybox configuration file</li> - <li><code>BUILDROOT_DL_DIR</code> to override the directory in which - Buildroot stores/retrieves downloaded files</li> - </ul> - - <p>An example that uses config files located in the toplevel directory and - in your $HOME:</p> - -<pre> - $ make UCLIBC_CONFIG_FILE=uClibc.config BUSYBOX_CONFIG_FILE=$HOME/bb.config -</pre> - - <p>If you want to use a compiler other than the default <code>gcc</code> - or <code>g++</code> for building helper-binaries on your host, then do</p> - -<pre> - $ make HOSTCXX=g++-4.3-HEAD HOSTCC=gcc-4.3-HEAD -</pre> - - <h2 id="custom_targetfs">Customizing the generated target filesystem</h2> - - <p>There are a few ways to customize the resulting target filesystem:</p> - - <ul> - <li>Customize the target filesystem directly and rebuild the image. - The target filesystem is available under <code>output/target/</code>. - You can simply make your changes here and run make afterwards — - this will rebuild the target filesystem image. This method allows you - to do anything to the target filesystem, but if you decide to - completely rebuild your toolchain and tools, these changes will be - lost.</li> - - <li>Create your own <i>target skeleton</i>. You can start with - the default skeleton available under <code>fs/skeleton</code> - and then customize it to suit your - needs. The <code>BR2_ROOTFS_SKELETON_CUSTOM</code> - and <code>BR2_ROOTFS_SKELETON_CUSTOM_PATH</code> will allow you - to specify the location of your custom skeleton. At build time, - the contents of the skeleton are copied to output/target before - any package installation.</li> - - <li>In the Buildroot configuration, you can specify the path to a - post-build script, that gets called <i>after</i> Buildroot builds all - the selected software, but <i>before</i> the rootfs packages are - assembled. The destination root filesystem folder is given as the - first argument to this script, and this script can then be used to - copy programs, static data or any other needed file to your target - filesystem.<br/>You should, however, use this feature with care. - Whenever you find that a certain package generates wrong or unneeded - files, you should fix that package rather than work around it with a - post-build cleanup script.</li> - - <li>A special package, <i>customize</i>, stored in - <code>package/customize</code> can be used. You can put all the - files that you want to see in the final target root filesystem - in <code>package/customize/source</code>, and then enable this - special package in the configuration system.</li> - </ul> - - <h2 id="custom_busybox">Customizing the Busybox configuration</h2> - - <p><a href="http://www.busybox.net/">Busybox</a> is very configurable, - and you may want to customize it. You can follow these simple steps to - do so. This method isn't optimal, but it's simple, and it works:</p> - - <ol> - <li>Do an initial compilation of Buildroot, with busybox, without - trying to customize it.</li> - - <li>Invoke <code>make busybox-menuconfig</code>. - The nice configuration tool appears, and you can - customize everything.</li> - - <li>Run the compilation of Buildroot again.</li> - </ol> - - <p>Otherwise, you can simply change the - <code>package/busybox/busybox-<version>.config</code> file, if you - know the options you want to change, without using the configuration tool. - </p> - - <p>If you want to use an existing config file for busybox, then see - section <a href="#environment_variables">environment variables</a>.</p> - - <h2 id="custom_uclibc">Customizing the uClibc configuration</h2> - - <p>Just like <a href="#custom_busybox">BusyBox</a>, - <a href="http://www.uclibc.org/">uClibc</a> offers a lot of - configuration options. They allow you to select various - functionalities depending on your needs and limitations.</p> - - <p>The easiest way to modify the configuration of uClibc is to - follow these steps:</p> - - <ol> - <li>Do an initial compilation of Buildroot without trying to - customize uClibc.</li> - - <li>Invoke <code>make uclibc-menuconfig</code>. - The nice configuration assistant, similar to - the one used in the Linux kernel or Buildroot, appears. Make - your configuration changes as appropriate.</li> - - <li>Copy the <code>$(O)/toolchain/uclibc-VERSION/.config</code> - file to a different place - (like <code>toolchain/uClibc/uClibc-myconfig.config</code>, - or <code>board/mymanufacturer/myboard/uClibc.config</code>) and - adjust the uClibc configuration (configuration - option <code>BR2_UCLIBC_CONFIG</code>) to use this configuration - instead of the default one.</li> - - <li>Run the compilation of Buildroot again.</li> - </ol> - - <p>Otherwise, you can simply change - <code>toolchain/uClibc/uClibc.config</code>, without running the - configuration assistant.</p> - - <p>If you want to use an existing config file for uclibc, then see - section <a href="#environment_variables">environment variables</a>.</p> - - <h2 id="custom_linux26">Customizing the Linux kernel configuration</h2> - - <p>The Linux kernel configuration can be customized just like - <a href="#custom_busybox">BusyBox</a> and - <a href="#custom_uclibc">uClibc</a> using <code>make linux-menuconfig - </code>. Make sure you have enabled the kernel build in <code>make - menuconfig</code> first. Once done, run <code>make</code> to (re)build - everything.</p> - - <p>If you want to use an existing config file for Linux, then see - section <a href="#environment_variables">environment variables</a>.</p> - - <h2 id="rebuilding_packages">Understanding how to rebuild packages</h2> - - <p>One of the most common questions asked by Buildroot - users is how to rebuild a given package or how to - remove a package without rebuilding everything from scratch.</p> - - <p>Removing a package is currently unsupported by Buildroot - without rebuilding from scratch. This is because Buildroot doesn't - keep track of which package installs what files in the - <code>output/staging</code> and <code>output/target</code> - directories. However, implementing clean package removal is on the - TODO-list of Buildroot developers.</p> - - <p>The easiest way to rebuild a single package from scratch is to - remove its build directory in <code>output/build</code>. Buildroot - will then re-extract, re-configure, re-compile and re-install this - package from scratch.</p> - - <p>However, if you don't want to rebuild the package completely - from scratch, a better understanding of the Buildroot internals is - needed. Internally, to keep track of which steps have been done - and which steps remain to be done, Buildroot maintains stamp - files (empty files that just tell whether this or that action - has been done). The problem is that these stamp files are not - uniformly named and handled by the different packages, so some - understanding of the particular package is needed.</p> - - <p>For packages relying on Buildroot packages infrastructures (see - <a href="#add_packages">this section</a> for details), the - following stamp files are relevant:</p> - - <ul> - <li><code>output/build/packagename-version/.stamp_configured</code>. If - removed, Buildroot will trigger the recompilation of the package - from the configuration step (execution of - <code>./configure</code>).</li> - - <li><code>output/build/packagename-version/.stamp_built</code>. If - removed, Buildroot will trigger the recompilation of the package - from the compilation step (execution of <code>make</code>).</li> - </ul> - - <p>For other packages, an analysis of the specific <i>package.mk</i> - file is needed. For example, the zlib Makefile used to look like this - (before it was converted to the generic package infrastructure):</p> - -<pre> -$(ZLIB_DIR)/.configured: $(ZLIB_DIR)/.patched - (cd $(ZLIB_DIR); rm -rf config.cache; \ - [...] - ) - touch $@ - -$(ZLIB_DIR)/libz.a: $(ZLIB_DIR)/.configured - $(MAKE) -C $(ZLIB_DIR) all libz.a - touch -c $@ -</pre> - - <p>If you want to trigger the reconfiguration, you need to - remove <code>output/build/zlib-version/.configured</code>. If - you want to trigger only the recompilation, you need to remove - <code>output/build/zlib-version/libz.a</code>.</p> - - <p>Note that most packages, if not all, will progressively be - ported over to the generic or autotools infrastructure, making it - much easier to rebuild individual packages.</p> - - <h2 id="buildroot_innards">How Buildroot works</h2> - - <p>As mentioned above, Buildroot is basically a set of Makefiles that - download, configure, and compile software with the correct options. It - also includes patches for various software packages — mainly the - ones involved in the cross-compilation tool chain (<code>gcc</code>, - <code>binutils</code> and <code>uClibc</code>).</p> - - <p>There is basically one Makefile per software package, and they are - named with the <code>.mk</code> extension. Makefiles are split into - three main sections:</p> - - <ul> - <li><b>toolchain</b> (in the <code>toolchain/</code> directory) contains - the Makefiles and associated files for all software related to the - cross-compilation toolchain: <code>binutils</code>, <code>gcc</code>, - <code>gdb</code>, <code>kernel-headers</code> and <code>uClibc</code>.</li> - - <li><b>package</b> (in the <code>package/</code> directory) contains the - Makefiles and associated files for all user-space tools that Buildroot - can compile and add to the target root filesystem. There is one - sub-directory per tool.</li> - - <li><b>target</b> (in the <code>target</code> directory) contains the - Makefiles and associated files for software related to the generation of - the target root filesystem image. Four types of filesystems are supported: - ext2, jffs2, cramfs and squashfs. For each of them there is a - sub-directory with the required files. There is also a - <code>default/</code> directory that contains the target filesystem - skeleton.</li> - </ul> - - <p>Each directory contains at least 2 files:</p> - - <ul> - <li><code>something.mk</code> is the Makefile that downloads, configures, - compiles and installs the package <code>something</code>.</li> - - <li><code>Config.in</code> is a part of the configuration tool - description file. It describes the options related to the - package.</li> - </ul> - - <p>The main Makefile performs the following steps (once the - configuration is done):</p> - - <ol> - <li>Create all the output directories: <code>staging</code>, - <code>target</code>, <code>build</code>, <code>stamps</code>, - etc. in the output directory (<code>output/</code> by default, - another value can be specified using <code>O=</code>)</li> - - <li>Generate all the targets listed in the - <code>BASE_TARGETS</code> variable. When an internal toolchain - is used, this means generating the cross-compilation - toolchain. When an external toolchain is used, this means checking - the features of the external toolchain and importing it into the - Buildroot environment.</li> - - <li>Generate all the targets listed in the <code>TARGETS</code> - variable. This variable is filled by all the individual - components' Makefiles. Generating these targets will - trigger the compilation of the userspace packages (libraries, - programs), the kernel, the bootloader and the generation of the - root filesystem images, depending on the configuration.</li> - </ol> - - <h2 id="board_support"> Creating your own board support</h2> - - <p>Creating your own board support in Buildroot allows users of a - particular hardware platform to easily build a system that is - known to work.</p> - - <p>To do so, you need to create a normal Buildroot configuration - that builds a basic system for the hardware: toolchain, kernel, - bootloader, filesystem and a simple Busybox-only userspace. No - specific package should be selected: the configuration should be - as minimal as possible, and should only build a working basic - Busybox system for the target platform. You can of course use more - complicated configurations for your internal projects, but the - Buildroot project will only integrate basic board - configurations. This is because package selections are highly - application-specific.</p> - - <p>Once you have a known working configuration, run <code>make - savedefconfig</code>. This will generate a - minimal <code>defconfig</code> file at the root of the Buildroot - source tree. Move this file into the <code>configs/</code> - directory, and rename it <code>MYBOARD_defconfig</code>.</p> - - <p>It is recommended to use as much as possible upstream versions - of the Linux kernel and bootloaders, and to use as much as - possible default kernel and bootloader configurations. If they are - incorrect for your platform, we encourage you to send fixes to the - corresponding upstream projects.</p> - - <p>However, in the mean time, you may want to store kernel or - bootloader configuration or patches specific to your target - platform. To do so, create a - directory <code>board/MANUFACTURER</code> and a - subdirectory <code>board/MANUFACTURER/BOARDNAME</code> (after - replacing, of course, MANUFACTURER and BOARDNAME with the - appropriate values, in lower case letters). You can then store - your patches and configurations in these directories, and - reference them from the main Buildroot configuration.</p> - - <h2 id="using_toolchain">Using the generated toolchain outside Buildroot</h2> - - <p>You may want to compile, for your target, your own programs or other - software that are not packaged in Buildroot. In order to do this you can - use the toolchain that was generated by Buildroot.</p> - - <p>The toolchain generated by Buildroot is located by default in - <code>output/host/</code>. The simplest way to use it is to add - <code>output/host/usr/bin/</code> to your PATH environment variable and - then to use <code>ARCH-linux-gcc</code>, <code>ARCH-linux-objdump</code>, - <code>ARCH-linux-ld</code>, etc.</p> - - <p>It is possible to relocate the toolchain — but - then <code>--sysroot</code> must be passed every time the compiler - is called to tell where the libraries and header files are.</p> - - <p>It is also possible to generate the Buildroot toolchain in a - directory other than <code>output/host</code> by using the <code> - Build options -> Host dir</code> option. - This could be useful if the toolchain must be shared with other users.</p> - - <h2 id="ccache-support">Using <code>ccache</code> in Buildroot</h2> - - <p><a href="http://ccache.samba.org">ccache</a> is a compiler - cache. It stores the object files resulting from each compilation - process, and is able to skip future compilation of the same source - file (with same compiler and same arguments) by using the - pre-existing object files. When doing almost identical builds from - scratch a number of times, it can nicely speed up the build - process.</p> - - <p><code>ccache</code> support is integrated in Buildroot. You - just have to enable <code>Enable compiler cache</code> - in <code>Build options</code>. This will automatically build - <code>ccache</code> and use it for every host and target - compilation.</p> - - <p>The cache is located - in <code>$HOME/.buildroot-ccache</code>. It is stored outside of - Buildroot output directory so that it can be shared by separate - Buildroot builds. If you want to get rid of the cache, simply - remove this directory.</p> - - <p>You can get statistics on the cache (its size, number of hits, - misses, etc.) by running <code>make ccache-stats</code>.</p> - - <h2 id="downloaded_packages">Location of downloaded packages</h2> - - <p>It might be useful to know that the various tarballs that are - downloaded by the Makefiles are all stored in the <code>DL_DIR</code> - which by default is the <code>dl</code> directory. It's useful, for - example, if you want to keep a complete version of Buildroot which is - known to be working with the associated tarballs. This will allow you to - regenerate the toolchain and the target filesystem with exactly the same - versions.</p> - - <p>If you maintain several Buildroot trees, it might be better to have a - shared download location. This can be accessed by creating a symbolic - link from the <code>dl</code> directory to the shared download location:</p> - -<pre> - $ ln -s <shared download location> dl -</pre> - - <p>Another way of accessing a shared download location is to - create the <code>BUILDROOT_DL_DIR</code> environment variable. - If this is set, then the value of DL_DIR in the project is - overridden. The following line should be added to - <code>"~/.bashrc"</code>.</p> - -<pre> - $ export BUILDROOT_DL_DIR <shared download location> -</pre> - - <h2 id="external_toolchain">Using an external toolchain</h2> - - <p>Using an already existing toolchain is useful for different - reasons:</p> - - <ul> - <li>you already have a toolchain that is known to work for your - specific CPU</li> - <li>you want to speed up the Buildroot build process by skipping - the long toolchain build part</li> - <li>the toolchain generation feature of Buildroot is not - sufficiently flexible for you (for example if you need to - generate a system with <i>glibc</i> instead of - <i>uClibc</i>)</li> - </ul> - - <p>Buildroot supports using existing toolchains through a - mechanism called <i>external toolchain</i>. The external toolchain - mechanism is enabled in the <code>Toolchain</code> menu, by - selecting <code>External toolchain</code> in <code>Toolchain - type</code>.</p> - - <p>Then, you have three solutions to use an external - toolchain:</p> - - <ul> - - <li>Use a predefined external toolchain profile, and let - Buildroot download, extract and install the toolchain. Buildroot - already knows about a few CodeSourcery toolchains for ARM, - PowerPC, MIPS and SuperH. Just select the toolchain profile - in <code>Toolchain</code> through the available ones. This is - definitely the easiest solution.</li> - - <li>Use a predefined external toolchain profile, but instead of - having Buildroot download and extract the toolchain, you can - tell Buildroot where your toolchain is already installed on your - system. Just select the toolchain profile - in <code>Toolchain</code> through the available ones, - unselect <code>Download toolchain automatically</code>, and fill - the <code>Toolchain path</code> text entry with the path to your - cross-compiling toolchain.</li> - - <li>Use a completely custom external toolchain. This is - particularly useful for toolchains generated using - Crosstool-NG. To do this, select the <code>Custom - toolchain</code> solution in the <code>Toolchain</code> - list. You need to fill the <code>Toolchain - path</code>, <code>Toolchain prefix</code> and <code>External - toolchain C library</code> options. Then, you have to tell - Buildroot what your external toolchain supports. If your - external toolchain uses the <i>glibc</i> library, you only have - to tell whether your toolchain supports C++ or not. If your - external toolchain uses the <i>uclibc</i> library, then you have - to tell Buildroot if it supports largefile, IPv6, RPC, - wide-char, locale, program invocation, threads and C++. At the - beginning of the execution, Buildroot will tell you if the - selected options do not match the toolchain configuration.</li> - - </ul> - - <p>Our external toolchain support has been tested with toolchains - from CodeSourcery, toolchains generated - by <a href="http://ymorin.is-a-geek.org/dokuwiki/projects/crosstool">Crosstool-NG</a>, - and toolchains generated by Buildroot itself. In general, all - toolchains that support the <i>sysroot</i> feature should - work. If not, do not hesitate to contact the developers.</p> - - <p>We do not support toolchains from - the <a href="http://www.denx.de/wiki/DULG/ELDK">ELDK of Denx</a>, - for two reasons:</p> - - <ul> - - <li>The ELDK does not contain a pure toolchain (i.e just the - compiler, binutils, the C and C++ libraries), but a toolchain - that comes with a very large set of pre-compiled libraries and - programs. Therefore, Buildroot cannot import the <i>sysroot</i> - of the toolchain, as it would contain hundreds of megabytes of - pre-compiled libraries that are normally built by - Buildroot.</li> - - <li>The ELDK toolchains have a completely non-standard custom - mechanism to handle multiple library variants. Instead of using - the standard GCC <i>multilib</i> mechanism, the ARM ELDK uses - different symbolic links to the compiler to differentiate - between library variants (for ARM soft-float and ARM VFP), and - the PowerPC ELDK compiler uses a <code>CROSS_COMPILE</code> - environment variable. This non-standard behaviour makes it - difficult to support ELDK in Buildroot.</li> - - </ul> - - <p>We also do not support using the distribution toolchain (i.e - the gcc/binutils/C library installed by your distribution) as the - toolchain to build software for the target. This is because your - distribution toolchain is not a "pure" toolchain (i.e only with - the C/C++ library), so we cannot import it properly into the - Buildroot build environment. So even if you are building a system - for a x86 or x86_64 target, you have to generate a - cross-compilation toolchain with Buildroot or Crosstool-NG.</p> - - <h2 id="add_packages">Adding new packages to Buildroot</h2> - - <p>This section covers how new packages (userspace libraries or - applications) can be integrated into Buildroot. It also shows how existing - packages are integrated, which is needed for fixing issues or tuning their - configuration.</p> - - <ul> - <li><a href="#package-directory">Package directory</a></li> - <li><a href="#config-in-file"><code>Config.in</code> file</a></li> - <li><a href="#mk-file">The <code>.mk</code> file</a> - <ul> - <li><a href="#generic-tutorial">Makefile for generic packages : tutorial</a></li> - <li><a href="#generic-reference">Makefile for generic packages : reference</a></li> - <li><a href="#autotools-tutorial">Makefile for autotools-based packages : tutorial</a></li> - <li><a href="#autotools-reference">Makefile for autotools-based packages : reference</a></li> - <li><a href="#cmake-tutorial">Makefile for CMake-based packages : tutorial</a></li> - <li><a href="#cmake-reference">Makefile for CMake-based packages : reference</a></li> - <li><a href="#manual-tutorial">Manual Makefile : tutorial</a></li> - </ul> - </li> - <li><a href="#gettext-integration">Gettext integration and interaction with packages</a></li> - </ul> - - <h3 id="package-directory">Package directory</h3> - - <p>First of all, create a directory under the <code>package</code> - directory for your software, for example <code>libfoo</code>.</p> - - <p>Some packages have been grouped by topic in a sub-directory: - <code>multimedia</code>, <code>x11r7</code>, and - <code>games</code>. If your package fits in one of these - categories, then create your package directory in these.</p> - - <h3 id="config-in-file"><code>Config.in</code> file</h3> - - <p>Then, create a file named <code>Config.in</code>. This file - will contain the option descriptions related to our - <code>libfoo</code> software that will be used and displayed in the - configuration tool. It should basically contain :</p> - -<pre> -config BR2_PACKAGE_LIBFOO - bool "libfoo" - help - This is a comment that explains what libfoo is. - - http://foosoftware.org/libfoo/ -</pre> - - <p>Of course, you can add other options to configure particular - things in your software. You can look at examples in other - packages. The syntax of the Config.in file is the same as the one - for the kernel Kconfig file. The documentation for this syntax is - available at - <a href="http://lxr.free-electrons.com/source/Documentation/kbuild/kconfig-language.txt">http://lxr.free-electrons.com/source/Documentation/kbuild/kconfig-language.txt</a> - </p> - - <p>Finally you have to add your new <code>libfoo/Config.in</code> to - <code>package/Config.in</code> (or in a category subdirectory if - you decided to put your package in one of the existing - categories). The files included there are <em>sorted - alphabetically</em> per category and are <em>NOT</em> supposed to - contain anything but the <em>bare</em> name of the package.</p> - -<pre> -source "package/libfoo/Config.in" -</pre> - - <h3 id="mk-file">The <code>.mk</code> file</h3> - - <p>Finally, here's the hardest part. Create a file named - <code>libfoo.mk</code>. It describes how the package should be - downloaded, configured, built, installed, etc.</p> - - <p>Depending on the package type, the <code>.mk</code> file must be - written in a different way, using different infrastructures:</p> - - <ul> - <li><b>Makefiles for generic packages</b> (not using autotools): These - are based on an infrastructure similar to the one used for - autotools-based packages, but requires a little more work from the - developer. They specify what should be done for the configuration, - compilation, installation and cleanup of the package. This - infrastructure must be used for all packages that do not use the - autotools as their build system. In the future, other specialized - infrastructures might be written for other build systems.<br/>We cover - them through a <a href="#generic-tutorial">tutorial</a> and a - <a href="#generic-reference">reference</a>.</li> - - <li><b>Makefiles for autotools-based software</b> (autoconf, automake, - etc.): We provide a dedicated infrastructure for such packages, since - autotools is a very common build system. This infrastructure <i>must - </i> be used for new packages that rely on the autotools as their - build system.<br/>We cover them through a - <a href="#autotools-tutorial">tutorial</a> and a - <a href="#autotools-reference">reference</a>.</li> - - <li><b>Manual Makefiles:</b> These are currently obsolete, and no new - manual Makefiles should be added. However, since there are still many - of them in the tree, we keep them documented in a - <a href="#manual-tutorial">tutorial</a>.</li> - </ul> - - <h4 id="generic-tutorial">Makefile for generic packages : tutorial</h4> - -<pre> -<span style="color: #000000">01:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">02:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">03:</span><span style="font-style: italic; color: #9A1900"> # libfoo</span> -<span style="color: #000000">04:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">05:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">06:</span><span style="color: #009900"> LIBFOO_VERSION</span> = 1.0 -<span style="color: #000000">07:</span><span style="color: #009900"> LIBFOO_SOURCE</span> = libfoo-<span style="color: #009900">$(LIBFOO_VERSION)</span>.tar.gz -<span style="color: #000000">08:</span><span style="color: #009900"> LIBFOO_SITE</span> = http://www.foosoftware.org/download -<span style="color: #000000">09:</span><span style="color: #009900"> LIBFOO_INSTALL_STAGING</span> = YES -<span style="color: #000000">10:</span><span style="color: #009900"> LIBFOO_DEPENDENCIES</span> = host-libaaa libbbb -<span style="color: #000000">11:</span> -<span style="color: #000000">12:</span> define LIBFOO_BUILD_CMDS -<span style="color: #000000">13:</span> <span style="color: #009900">$(MAKE)</span> CC=<span style="color: #009900">"$(TARGET_CC)"</span> LD=<span style="color: #009900">"$(TARGET_LD)"</span> -C <span style="color: #009900">$(@D)</span> all -<span style="color: #000000">14:</span> endef -<span style="color: #000000">15:</span> -<span style="color: #000000">16:</span> define LIBFOO_INSTALL_STAGING_CMDS -<span style="color: #000000">17:</span> <span style="color: #009900">$(INSTALL)</span> -D -m 0755 <span style="color: #009900">$(@D)</span>/libfoo.a <span style="color: #009900">$(STAGING_DIR)</span>/usr/lib/libfoo.a -<span style="color: #000000">18:</span> <span style="color: #009900">$(INSTALL)</span> -D -m 0644 <span style="color: #009900">$(@D)</span>/foo.h <span style="color: #009900">$(STAGING_DIR)</span>/usr/include/foo.h -<span style="color: #000000">19:</span> <span style="color: #009900">$(INSTALL)</span> -D -m 0755 <span style="color: #009900">$(@D)</span>/libfoo.so* <span style="color: #009900">$(STAGING_DIR)</span>/usr/lib -<span style="color: #000000">20:</span> endef -<span style="color: #000000">21:</span> -<span style="color: #000000">22:</span> define LIBFOO_INSTALL_TARGET_CMDS -<span style="color: #000000">23:</span> <span style="color: #009900">$(INSTALL)</span> -D -m 0755 <span style="color: #009900">$(@D)</span>/libfoo.so* <span style="color: #009900">$(TARGET_DIR)</span>/usr/lib -<span style="color: #000000">24:</span> <span style="color: #009900">$(INSTALL)</span> -d -m 0755 <span style="color: #009900">$(TARGET_DIR)</span>/etc/foo.d -<span style="color: #000000">25:</span> endef -<span style="color: #000000">26:</span> -<span style="color: #000000">27:</span><span style="color: #009900"> $(eval $(call GENTARGETS,package,libfoo))</span> -</pre> - - <p>The Makefile begins on line 6 to 8 with metadata information: the - version of the package (<code>LIBFOO_VERSION</code>), the name of the - tarball containing the package (<code>LIBFOO_SOURCE</code>) and the - Internet location at which the tarball can be downloaded - (<code>LIBFOO_SITE</code>). All variables must start with the same prefix, - <code>LIBFOO_</code> in this case. This prefix is always the uppercased - version of the package name (see below to understand where the package - name is defined).</p> - - <p>On line 9, we specify that this package wants to install something to - the staging space. This is often needed for libraries, since they must - install header files and other development files in the staging space. - This will ensure that the commands listed in the - <code>LIBFOO_INSTALL_STAGING_CMDS</code> variable will be executed.</p> - - <p>On line 10, we specify the list of dependencies this package relies - on. These dependencies are listed in terms of lower-case package names, - which can be packages for the target (without the <code>host-</code> - prefix) or packages for the host (with the <code>host-</code>) prefix). - Buildroot will ensure that all these packages are built and installed - <i>before</i> the current package starts its configuration.</p> - - <p>The rest of the Makefile defines what should be done at the different - steps of the package configuration, compilation and installation. - <code>LIBFOO_BUILD_CMDS</code> tells what steps should be performed to - build the package. <code>LIBFOO_INSTALL_STAGING_CMDS</code> tells what - steps should be performed to install the package in the staging space. - <code>LIBFOO_INSTALL_TARGET_CMDS</code> tells what steps should be - performed to install the package in the target space.</p> - - <p>All these steps rely on the <code>$(@D)</code> variable, which - contains the directory where the source code of the package has been - extracted.</p> - - <p>Finally, on line 27, we call the <code>GENTARGETS</code> which - generates, according to the variables defined previously, all the - Makefile code necessary to make your package working.</p> - - <h4 id="generic-reference">Makefile for generic packages : reference</h4> - - <p>The <code>GENTARGETS</code> macro takes three arguments:</p> - - <ul> - <li>The first argument is the package directory prefix. If your - package is in <code>package/libfoo</code>, then the directory prefix - is <code>package</code>. If your package is in - <code>package/editors/foo</code>, then the directory prefix must be - <code>package/editors</code>.</li> - - <li>The second argument is the lower-cased package name. It must match - the prefix of the variables in the <code>.mk</code> file and must - match the configuration option name in the <code>Config.in</code> - file. For example, if the package name is <code>libfoo</code>, then the - variables in the <code>.mk</code> file must start with - <code>LIBFOO_</code> and the configuration option in the - <code>Config.in</code> file must be <code>BR2_PACKAGE_LIBFOO</code>.</li> - - <li>The third argument is optional. It can be used to tell if the - package is a target package (cross-compiled for the target) or a host - package (natively compiled for the host). If unspecified, it is - assumed that it is a target package. See below for details.</li> - </ul> - - <p>For a given package, in a single <code>.mk</code> file, it is - possible to call GENTARGETS twice, once to create the rules to generate - a target package and once to create the rules to generate a host package: - </p> - -<pre> -$(eval $(call GENTARGETS,package,libfoo)) -$(eval $(call GENTARGETS,package,libfoo,host)) -</pre> - - <p>This might be useful if the compilation of the target package - requires some tools to be installed on the host. If the package name is - <code>libfoo</code>, then the name of the package for the target is also - <code>libfoo</code>, while the name of the package for the host is - <code>host-libfoo</code>. These names should be used in the DEPENDENCIES - variables of other packages, if they depend on <code>libfoo</code> or - <code>host-libfoo</code>.</p> - - <p>The call to the <code>GENTARGETS</code> macro <b>must</b> be at the - end of the <code>.mk</code> file, after all variable definitions.</p> - - <p>For the target package, the <code>GENTARGETS</code> uses the - variables defined by the .mk file and prefixed by the uppercased package - name: <code>LIBFOO_*</code>. For the host package, it uses the - <code>HOST_LIBFOO_*</code>. For <i>some</i> variables, if the - <code>HOST_LIBFOO_</code> prefixed variable doesn't exist, the package - infrastructure uses the corresponding variable prefixed by - <code>LIBFOO_</code>. This is done for variables that are likely to have - the same value for both the target and host packages. See below for - details.</p> - - <p>The list of variables that can be set in a <code>.mk</code> file to - give metadata information is (assuming the package name is - <code>libfoo</code>) :</p> - - <ul> - <li><code>LIBFOO_VERSION</code>, mandatory, must contain the - version of the package. Note that - if <code>HOST_LIBFOO_VERSION</code> doesn't exist, it is assumed - to be the same as <code>LIBFOO_VERSION</code>. It can also be a - Subversion or Git branch or tag, for packages that are fetched - directly from their revision control system.<br/> - Example: <code>LIBFOO_VERSION = 0.1.2</code></li> - - <li><code>LIBFOO_SOURCE</code> may contain the name of the tarball of - the package. If <code>HOST_LIBFOO_SOURCE</code> is not specified, it - defaults to <code>LIBFOO_SOURCE</code>. If none are specified, then - the value is assumed to be - <code>packagename-$(LIBFOO_VERSION).tar.gz</code>.<br/>Example: - <code>LIBFOO_SOURCE = foobar-$(LIBFOO_VERSION).tar.bz2</code></li> - - <li><code>LIBFOO_PATCH</code> may contain the name of a patch, that - will be downloaded from the same location as the tarball indicated in - <code>LIBFOO_SOURCE</code>. If <code>HOST_LIBFOO_PATCH</code> is not - specified, it defaults to <code>LIBFOO_PATCH</code>. Also note that - another mechanism is available to patch a package: all files of the - form <code>packagename-packageversion-description.patch</code> present - in the package directory inside Buildroot will be applied to the - package after extraction.</li> - - <li><code>LIBFOO_SITE</code> may contain the Internet location - of the package. It can either be the HTTP or FTP location of a - tarball, or the URL of a Git or Subversion repository - (see <code>LIBFOO_SITE_METHOD</code> - below). If <code>HOST_LIBFOO_SITE</code> is not specified, it - defaults to <code>LIBFOO_SITE</code>. If none are specified, - then the location is assumed to be - <code>http://$$(BR2_SOURCEFORGE_MIRROR).dl.sourceforge.net/sourceforge/packagename</code>. - <br/>Examples:<br/> - <code>LIBFOO_SITE=http://www.libfoosoftware.org/libfoo</code><br/> - <code>LIBFOO_SITE=http://svn.xiph.org/trunk/Tremor/</code></li> - - <li><code>LIBFOO_SITE_METHOD</code> may contain the method to - fetch the package source code. It can either - be <code>wget</code> (for normal FTP/HTTP downloads of - tarballs), <code>svn</code>, <code>git</code> or <code>bzr</code>. - When not specified, it is guessed from the URL given - in <code>LIBFOO_SITE</code>: <code>svn://</code>, <code>git://</code> - and <code>bzr://</code> URLs will use the <code>svn</code>, - <code>git</code> and <code>bzr</code> methods respectively. All other - URL-types will use the <code>wget</code> method. So for example, in the - case of a package whose source code is available through - Subversion repository on HTTP, one <i>must</i> - specifiy <code>LIBFOO_SITE_METHOD=svn</code>. For <code>svn</code> - and <code>git</code> methods, what Buildroot does is a - checkout/clone of the repository which is then tarballed and - stored into the download cache. Next builds will not - checkout/clone again, but will use the tarball - directly. When <code>HOST_LIBFOO_SITE_METHOD</code> is not - specified, it defaults to the value - of <code>LIBFOO_SITE_METHOD</code>. See <code>package/multimedia/tremor/</code> - for an example.</li> - - <li><code>LIBFOO_DEPENDENCIES</code> lists the dependencies (in terms - of package name) that are required for the current target package to - compile. These dependencies are guaranteed to be compiled and - installed before the configuration of the current package starts. In a - similar way, <code>HOST_LIBFOO_DEPENDENCIES</code> lists the - dependency for the current host package.</li> - - <li><code>LIBFOO_INSTALL_STAGING</code> can be set to <code>YES</code> - or <code>NO</code> (default). If set to <code>YES</code>, then the - commands in the <code>LIBFOO_INSTALL_STAGING_CMDS</code> variables are - executed to install the package into the staging directory.</li> - - <li><code>LIBFOO_INSTALL_TARGET</code> can be set to <code>YES</code> - (default) or <code>NO</code>. If set to <code>YES</code>, then the - commands in the <code>LIBFOO_INSTALL_TARGET_CMDS</code> variables are - executed to install the package into the target directory.</li> </ul> - - <p>The recommended way to define these variables is to use the following - syntax:</p> - -<pre> -LIBFOO_VERSION = 2.32 -</pre> - - <p>Now, the variables that define what should be performed at the - different steps of the build process.</p> - - <ul> - <li><code>LIBFOO_CONFIGURE_CMDS</code>, used to list the actions to be - performed to configure the package before its compilation</li> - - <li><code>LIBFOO_BUILD_CMDS</code>, used to list the actions to be - performed to compile the package</li> - - <li><code>HOST_LIBFOO_INSTALL_CMDS</code>, used to list the actions to - be performed to install the package, when the package is a host - package. The package must install its files to the directory given by - <code>$(HOST_DIR)</code>. All files, including development files such - as headers should be installed, since other packages might be compiled - on top of this package.</li> - - <li><code>LIBFOO_INSTALL_TARGET_CMDS</code>, used to list the actions - to be performed to install the package to the target directory, when - the package is a target package. The package must install its files to - the directory given by <code>$(TARGET_DIR)</code>. Only the files - required for <i>documentation</i> and <i>execution</i> of the package - should be installed. Header files should not be installed, they will - be copied to the target, if the - <code>development files in target filesystem</code> option is selected. - </li> - - <li><code>LIBFOO_INSTALL_STAGING_CMDS</code>, used to list the actions - to be performed to install the package to the staging directory, when - the package is a target package. The package must install its files to - the directory given by <code>$(STAGING_DIR)</code>. All development - files should be installed, since they might be needed to compile other - packages.</li> - - <li><code>LIBFOO_CLEAN_CMDS</code>, used to list the actions to - perform to clean up the build directory of the package.</li> - - <li><code>LIBFOO_UNINSTALL_TARGET_CMDS</code>, used to list the actions - to uninstall the package from the target directory - <code>$(TARGET_DIR)</code></li> - - <li><code>LIBFOO_UNINSTALL_STAGING_CMDS</code>, used to list the - actions to uninstall the package from the staging directory - <code>$(STAGING_DIR)</code>.</li> - </ul> - - <p>The preferred way to define these variables is:</p> - -<pre> -define LIBFOO_CONFIGURE_CMDS - action 1 - action 2 - action 3 -endef -</pre> - - <p>In the action definitions, you can use the following variables:</p> - - <ul> - <li><code>$(@D)</code>, which contains the directory in which the - package source code has been uncompressed.</li> - - <li><code>$(TARGET_CC)</code>, <code>$(TARGET_LD)</code>, etc. to get - the target cross-compilation utilities</li> - - <li><code>$(TARGET_CROSS)</code> to get the cross-compilation - toolchain prefix</li> - - <li>Of course the <code>$(HOST_DIR)</code>, <code>$(STAGING_DIR)</code> - and <code>$(TARGET_DIR)</code> variables to install the packages - properly.</li> - </ul> - - <p>The last feature of the generic infrastructure is the ability to add - hooks. These define further actions to perform after existing steps. - Most hooks aren't really useful for generic packages, since the - <code>.mk</code> file already has full control over the actions - performed in each step of the package construction. The hooks are more - useful for packages using the autotools infrastructure described below. - However, since they are provided by the generic infrastructure, they are - documented here. The exception is <code>LIBFOO_POST_PATCH_HOOKS</code>. - Patching the package is not user definable, so - <code>LIBFOO_POST_PATCH_HOOKS</code> will be userful for generic packages. - </p> - - <p>The following hook points are available:</p> - - <ul> - <li><code>LIBFOO_POST_PATCH_HOOKS</code></li> - <li><code>LIBFOO_PRE_CONFIGURE_HOOKS</code></li> - <li><code>LIBFOO_POST_CONFIGURE_HOOKS</code></li> - <li><code>LIBFOO_POST_BUILD_HOOKS</code></li> - <li><code>LIBFOO_POST_INSTALL_HOOKS</code> (for host packages only)</li> - <li><code>LIBFOO_POST_INSTALL_STAGING_HOOKS</code> (for target packages only)</li> - <li><code>LIBFOO_POST_INSTALL_TARGET_HOOKS</code> (for target packages only)</li> - </ul> - - <p>These variables are <i>lists</i> of variable names containing actions - to be performed at this hook point. This allows several hooks to be - registered at a given hook point. Here is an example:</p> - -<pre> -define LIBFOO_POST_PATCH_FIXUP - action1 - action2 -endef - -LIBFOO_POST_PATCH_HOOKS += LIBFOO_POST_PATCH_FIXUP -</pre> - - <h4 id="autotools-tutorial">Makefile for autotools-based packages : tutorial</h4> - - <p>First, let's see how to write a <code>.mk</code> file for an - autotools-based package, with an example :</p> - -<pre> -<span style="color: #000000">01:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">02:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">03:</span><span style="font-style: italic; color: #9A1900"> # libfoo</span> -<span style="color: #000000">04:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">05:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">06:</span><span style="color: #009900"> LIBFOO_VERSION</span> = 1.0 -<span style="color: #000000">07:</span><span style="color: #009900"> LIBFOO_SOURCE</span> = libfoo-<span style="color: #009900">$(LIBFOO_VERSION)</span>.tar.gz -<span style="color: #000000">08:</span><span style="color: #009900"> LIBFOO_SITE</span> = http://www.foosoftware.org/download -<span style="color: #000000">09:</span><span style="color: #009900"> LIBFOO_INSTALL_STAGING</span> = YES -<span style="color: #000000">10:</span><span style="color: #009900"> LIBFOO_INSTALL_TARGET</span> = YES -<span style="color: #000000">11:</span><span style="color: #009900"> LIBFOO_CONF_OPT</span> = --enable-shared -<span style="color: #000000">12:</span><span style="color: #009900"> LIBFOO_DEPENDENCIES</span> = libglib2 host-pkg-config -<span style="color: #000000">13:</span> -<span style="color: #000000">14:</span><span style="color: #009900"> $(eval $(call AUTOTARGETS,package,libfoo))</span> -</pre> - - <p>On line 6, we declare the version of the package.</p> - - <p>On line 7 and 8, we declare the name of the tarball and the location - of the tarball on the Web. Buildroot will automatically download the - tarball from this location.</p> - - <p>On line 9, we tell Buildroot to install the package to the staging - directory. The staging directory, located in <code>output/staging/</code> - is the directory where all the packages are installed, including their - development files, etc. By default, packages are not installed to the - staging directory, since usually, only libraries need to be installed in - the staging directory: their development files are needed to compile - other libraries or applications depending on them. Also by default, when - staging installation is enabled, packages are installed in this location - using the <code>make install</code> command.</p> - - <p>On line 10, we tell Buildroot to also install the package to the - target directory. This directory contains what will become the root - filesystem running on the target. Usually, we try not to install header - files and to install stripped versions of the binary. By default, target - installation is enabled, so in fact, this line is not strictly - necessary. Also by default, packages are installed in this location - using the <code>make install</code> command.</p> - - <p>On line 11, we tell Buildroot to pass a custom configure option, that - will be passed to the <code>./configure</code> script before configuring - and building the package.</p> - - <p>On line 12, we declare our dependencies, so that they are built - before the build process of our package starts.</p> - - <p>Finally, on line line 14, we invoke the <code>AUTOTARGETS</code> - macro that generates all the Makefile rules that actually allows the - package to be built.</p> - - <h4 id="autotools-reference">Makefile for autotools packages : reference</h4> - - <p>The main macro of the autotools package infrastructure is - <code>AUTOTARGETS</code>. It has the same number of arguments and the - same semantic as the <code>GENTARGETS</code> macro, which is the main - macro of the generic package infrastructure. For autotools packages, the - ability to have target and host packages is also available (and is - actually widely used).</p> - - <p>Just like the generic infrastructure, the autotools infrastructure - works by defining a number of variables before calling the - <code>AUTOTARGETS</code> macro.</p> - - <p>First, all the package metadata information variables that exist in the - generic infrastructure also exist in the autotools infrastructure: - <code>LIBFOO_VERSION</code>, <code>LIBFOO_SOURCE</code>, - <code>LIBFOO_PATCH</code>, <code>LIBFOO_SITE</code>, - <code>LIBFOO_SUBDIR</code>, <code>LIBFOO_DEPENDENCIES</code>, - <code>LIBFOO_INSTALL_STAGING</code>, <code>LIBFOO_INSTALL_TARGET</code>.</p> - - <p>A few additional variables, specific to the autotools infrastructure, - can also be defined. Many of them are only useful in very specific - cases, typical packages will therefore only use a few of them.</p> - - <ul> - <li><code>LIBFOO_SUBDIR</code> may contain the name of a subdirectory - inside the package that contains the configure script. This is useful, - if for example, the main configure script is not at the root of the - tree extracted by the tarball. If <code>HOST_LIBFOO_SUBDIR</code> is - not specified, it defaults to <code>LIBFOO_SUBDIR</code>.</li> - - <li><code>LIBFOO_CONF_ENV</code>, to specify additional environment - variables to pass to the configure script. By default, empty.</li> - - <li><code>LIBFOO_CONF_OPT</code>, to specify additional configure - options to pass to the configure script. By default, empty.</li> - - <li><code>LIBFOO_MAKE</code>, to specify an alternate <code>make</code> - command. This is typically useful when parallel make is enabled in - the configuration (using <code>BR2_JLEVEL</code>) but that this - feature should be disabled for the given package, for one reason or - another. By default, set to <code>$(MAKE)</code>. If parallel building - is not supported by the package, then it should be set to - <code>LIBFOO_MAKE=$(MAKE1)</code>.</li> - - <li><code>LIBFOO_MAKE_ENV</code>, to specify additional environment - variables to pass to make in the build step. These are passed before - the <code>make</code> command. By default, empty.</li> - - <li><code>LIBFOO_MAKE_OPT</code>, to specify additional variables to - pass to make in the build step. These are passed after the - <code>make</code> command. By default, empty.</li> - - <li><code>LIBFOO_AUTORECONF</code>, tells whether the package should - be autoreconfigured or not (i.e, if the configure script and - Makefile.in files should be re-generated by re-running autoconf, - automake, libtool, etc.). Valid values are <code>YES</code> and - <code>NO</code>. By default, the value is <code>NO</code></li> - - <li><code>LIBFOO_AUTORECONF_OPT</code> to specify additional options - passed to the <i>autoreconf</i> program if - <code>LIBFOO_AUTORECONF=YES</code>. By default, empty.</li> - - <li><code>LIBFOO_LIBTOOL_PATCH</code> tells whether the Buildroot - patch to fix libtool cross-compilation issues should be applied or - not. Valid values are <code>YES</code> and <code>NO</code>. By - default, the value is <code>YES</code></li> - - <li><code>LIBFOO_INSTALL_STAGING_OPT</code> contains the make options - used to install the package to the staging directory. By default, the - value is <code>DESTDIR=$$(STAGING_DIR) install</code>, which is - correct for most autotools packages. It is still possible to override - it.</li> - - <li><code>LIBFOO_INSTALL_TARGET_OPT</code> contains the make options - used to install the package to the target directory. By default, the - value is <code>DESTDIR=$$(TARGET_DIR) install</code>. The default - value is correct for most autotools packages, but it is still possible - to override it if needed.</li> - - <li><code>LIBFOO_CLEAN_OPT</code> contains the make options used to - clean the package. By default, the value is <code>clean</code>.</li> - - <li><code>LIBFOO_UNINSTALL_STAGING_OPT</code>, contains the make - options used to uninstall the package from the staging directory. By - default, the value is <code>DESTDIR=$$(STAGING_DIR) uninstall</code>.</li> - - <li><code>LIBFOO_UNINSTALL_TARGET_OPT</code>, contains the make - options used to uninstall the package from the target directory. By - default, the value is <code>DESTDIR=$$(TARGET_DIR) uninstall</code>.</li> - </ul> - - <p>With the autotools infrastructure, all the steps required to build - and install the packages are already defined, and they generally work - well for most autotools-based packages. However, when required, it is - still possible to customize what is done in any particular step:</p> - - <ul> - <li>By adding a post-operation hook (after extract, patch, configure, - build or install). See the reference documentation of the generic - infrastructure for details.</li> - - <li>By overriding one of the steps. For example, even if the autotools - infrastructure is used, if the package <code>.mk</code> file defines its - own <code>LIBFOO_CONFIGURE_CMDS</code> variable, it will be used - instead of the default autotools one. However, using this method - should be restricted to very specific cases. Do not use it in the - general case.</li> - </ul> - - <h4 id="cmake-tutorial">Makefile for CMake-based packages : tutorial</h4> - - <p>First, let's see how to write a <code>.mk</code> file for a CMake-based - package, with an example :</p> - -<pre> -<span style="color: #000000">01:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">02:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">03:</span><span style="font-style: italic; color: #9A1900"> # libfoo</span> -<span style="color: #000000">04:</span><span style="font-style: italic; color: #9A1900"> #</span> -<span style="color: #000000">05:</span><span style="font-style: italic; color: #9A1900"> #############################################################</span> -<span style="color: #000000">06:</span><span style="color: #009900"> LIBFOO_VERSION</span> = 1.0 -<span style="color: #000000">07:</span><span style="color: #009900"> LIBFOO_SOURCE</span> = libfoo-<span style="color: #009900">$(LIBFOO_VERSION)</span>.tar.gz -<span style="color: #000000">08:</span><span style="color: #009900"> LIBFOO_SITE</span> = http://www.foosoftware.org/download -<span style="color: #000000">09:</span><span style="color: #009900"> LIBFOO_INSTALL_STAGING</span> = YES -<span style="color: #000000">10:</span><span style="color: #009900"> LIBFOO_INSTALL_TARGET</span> = YES -<span style="color: #000000">11:</span><span style="color: #009900"> LIBFOO_CONF_OPT</span> = -DBUILD_DEMOS=ON -<span style="color: #000000">12:</span><span style="color: #009900"> LIBFOO_DEPENDENCIES</span> = libglib2 host-pkg-config -<span style="color: #000000">13:</span> -<span style="color: #000000">14:</span><span style="color: #009900"> $(eval $(call CMAKETARGETS,package,libfoo))</span> -</pre> - - <p>On line 6, we declare the version of the package.</p> - - <p>On line 7 and 8, we declare the name of the tarball and the location - of the tarball on the Web. Buildroot will automatically download the - tarball from this location.</p> - - <p>On line 9, we tell Buildroot to install the package to the staging - directory. The staging directory, located in <code>output/staging/</code> - is the directory where all the packages are installed, including their - development files, etc. By default, packages are not installed to the - staging directory, since usually, only libraries need to be installed in - the staging directory: their development files are needed to compile - other libraries or applications depending on them. Also by default, when - staging installation is enabled, packages are installed in this location - using the <code>make install</code> command.</p> - - <p>On line 10, we tell Buildroot to also install the package to the - target directory. This directory contains what will become the root - filesystem running on the target. Usually, we try not to install header - files and to install stripped versions of the binary. By default, target - installation is enabled, so in fact, this line is not strictly - necessary. Also by default, packages are installed in this location - using the <code>make install</code> command.</p> - - <p>On line 11, we tell Buildroot to pass custom options to CMake when it is - configuring the package.</p> - - <p>On line 12, we declare our dependencies, so that they are built - before the build process of our package starts.</p> - - <p>Finally, on line line 14, we invoke the <code>CMAKETARGETS</code> - macro that generates all the Makefile rules that actually allows the - package to be built.</p> - - <h4 id="cmake-reference">Makefile for CMake packages : reference</h4> - - <p>The main macro of the CMake package infrastructure is - <code>CMAKETARGETS</code>. It has the same number of arguments and the - same semantic as the <code>GENTARGETS</code> macro, which is the main - macro of the generic package infrastructure. For CMake packages, the - ability to have target and host packages is also available.</p> - - <p>Just like the generic infrastructure, the CMake infrastructure - works by defining a number of variables before calling the - <code>CMAKETARGETS</code> macro.</p> - - <p>First, all the package metadata information variables that exist in the - generic infrastructure also exist in the CMake infrastructure: - <code>LIBFOO_VERSION</code>, <code>LIBFOO_SOURCE</code>, - <code>LIBFOO_PATCH</code>, <code>LIBFOO_SITE</code>, - <code>LIBFOO_SUBDIR</code>, <code>LIBFOO_DEPENDENCIES</code>, - <code>LIBFOO_INSTALL_STAGING</code>, <code>LIBFOO_INSTALL_TARGET</code>.</p> - - <p>A few additional variables, specific to the CMake infrastructure, - can also be defined. Many of them are only useful in very specific - cases, typical packages will therefore only use a few of them.</p> - - <ul> - <li><code>LIBFOO_SUBDIR</code> may contain the name of a subdirectory - inside the package that contains the main CMakeLists.txt file. This is - useful, if for example, the main CMakeLists.txt file is not at the root - of the tree extracted by the tarball. If <code>HOST_LIBFOO_SUBDIR</code> - is not specified, it defaults to <code>LIBFOO_SUBDIR</code>.</li> - - <li><code>LIBFOO_CONF_ENV</code>, to specify additional environment - variables to pass to CMake. By default, empty.</li> - - <li><code>LIBFOO_CONF_OPT</code>, to specify additional configure - options to pass to CMake. By default, empty.</li> - - <li><code>LIBFOO_MAKE</code>, to specify an alternate <code>make</code> - command. This is typically useful when parallel make is enabled in - the configuration (using <code>BR2_JLEVEL</code>) but that this - feature should be disabled for the given package, for one reason or - another. By default, set to <code>$(MAKE)</code>. If parallel building - is not supported by the package, then it should be set to - <code>LIBFOO_MAKE=$(MAKE1)</code>.</li> - - <li><code>LIBFOO_MAKE_ENV</code>, to specify additional environment - variables to pass to make in the build step. These are passed before - the <code>make</code> command. By default, empty.</li> - - <li><code>LIBFOO_MAKE_OPT</code>, to specify additional variables to - pass to make in the build step. These are passed after the - <code>make</code> command. By default, empty.</li> - - <li><code>LIBFOO_INSTALL_STAGING_OPT</code> contains the make options - used to install the package to the staging directory. By default, the - value is <code>DESTDIR=$$(STAGING_DIR) install</code>, which is - correct for most CMake packages. It is still possible to override - it.</li> - - <li><code>LIBFOO_INSTALL_TARGET_OPT</code> contains the make options - used to install the package to the target directory. By default, the - value is <code>DESTDIR=$$(TARGET_DIR) install</code>. The default - value is correct for most CMake packages, but it is still possible - to override it if needed.</li> - - <li><code>LIBFOO_CLEAN_OPT</code> contains the make options used to - clean the package. By default, the value is <code>clean</code>.</li> - </ul> - - <p>With the CMake infrastructure, all the steps required to build - and install the packages are already defined, and they generally work - well for most CMake-based packages. However, when required, it is - still possible to customize what is done in any particular step:</p> - - <ul> - <li>By adding a post-operation hook (after extract, patch, configure, - build or install). See the reference documentation of the generic - infrastructure for details.</li> - - <li>By overriding one of the steps. For example, even if the CMake - infrastructure is used, if the package <code>.mk</code> file defines its - own <code>LIBFOO_CONFIGURE_CMDS</code> variable, it will be used - instead of the default CMake one. However, using this method - should be restricted to very specific cases. Do not use it in the - general case.</li> - </ul> - - <h4 id ="manual-tutorial">Manual Makefile : tutorial</h4> - - <p><b>NOTE: new manual makefiles should not be created, and existing - manual makefiles should be converted either to the generic, autotools - or cmake infrastructure. This section is only kept to document the existing - manual makefiles and to help understand how they work.</b></p> - -<pre> -01: ############################################################# -02: # -03: # libfoo -04: # -05: ############################################################# -<span id="ex2line6">06: LIBFOO_VERSION:=1.0</span> -07: LIBFOO_SOURCE:=libfoo-$(LIBFOO_VERSION).tar.gz -08: LIBFOO_SITE:=http://www.foosoftware.org/downloads -09: LIBFOO_DIR:=$(BUILD_DIR)/foo-$(FOO_VERSION) -10: LIBFOO_BINARY:=foo -11: LIBFOO_TARGET_BINARY:=usr/bin/foo -12: -<span id="ex2line13">13: $(DL_DIR)/$(LIBFOO_SOURCE):</span> -14: $(call DOWNLOAD,$(LIBFOO_SITE),$(LIBFOO_SOURCE)) -15: -<span id="ex2line16">16: $(LIBFOO_DIR)/.source: $(DL_DIR)/$(LIBFOO_SOURCE)</span> -17: $(ZCAT) $(DL_DIR)/$(LIBFOO_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) - -18: touch $@ -19: -<span id="ex2line20">20: $(LIBFOO_DIR)/.configured: $(LIBFOO_DIR)/.source</span> -21: (cd $(LIBFOO_DIR); rm -rf config.cache; \ -22: $(TARGET_CONFIGURE_OPTS) \ -23: $(TARGET_CONFIGURE_ARGS) \ -24: ./configure \ -25: --target=$(GNU_TARGET_NAME) \ -26: --host=$(GNU_TARGET_NAME) \ -27: --build=$(GNU_HOST_NAME) \ -28: --prefix=/usr \ -29: --sysconfdir=/etc \ -30: ) -31: touch $@ -32: -<span id="ex2line33">33: $(LIBFOO_DIR)/$(LIBFOO_BINARY): $(LIBFOO_DIR)/.configured</span> -34: $(MAKE) CC=$(TARGET_CC) -C $(LIBFOO_DIR) -35: -<span id="ex2line36">36: $(TARGET_DIR)/$(LIBFOO_TARGET_BINARY): $(LIBFOO_DIR)/$(LIBFOO_BINARY)</span> -37: $(MAKE) DESTDIR=$(TARGET_DIR) -C $(LIBFOO_DIR) install-strip -38: rm -Rf $(TARGET_DIR)/usr/man -39: -<span id="ex2line40">40: libfoo: uclibc ncurses $(TARGET_DIR)/$(LIBFOO_TARGET_BINARY)</span> -41: -<span id="ex2line42">42: libfoo-source: $(DL_DIR)/$(LIBFOO_SOURCE)</span> -43: -<span id="ex2line44">44: libfoo-clean:</span> -45: $(MAKE) prefix=$(TARGET_DIR)/usr -C $(LIBFOO_DIR) uninstall -46: -$(MAKE) -C $(LIBFOO_DIR) clean -47: -<span id="ex2line48">48: libfoo-dirclean:</span> -49: rm -rf $(LIBFOO_DIR) -50: -<span id="ex2line51">51: #############################################################</span> -52: # -53: # Toplevel Makefile options -54: # -55: ############################################################# -56: ifeq ($(BR2_PACKAGE_LIBFOO),y) -57: TARGETS+=libfoo -58: endif -</pre> - - <p>First of all, this Makefile example works for a package which - comprises a single binary executable. For other software, such as - libraries or more complex stuff with multiple binaries, it must be - adapted. For examples look at the other <code>*.mk</code> files in the - <code>package</code> directory.</p> - - <p>At lines <a href="#ex2line6">6-11</a>, a couple of useful variables are - defined:</p> - - <ul> - <li><code>LIBFOO_VERSION</code>: The version of <i>libfoo</i> that - should be downloaded.</li> - - <li><code>LIBFOO_SOURCE</code>: The name of the tarball of <i>libfoo</i> - on the download website or FTP site. As you can see - <code>LIBFOO_VERSION</code> is used.</li> - - <li><code>LIBFOO_SITE</code>: The HTTP or FTP site from which - <i>libfoo</i> archive is downloaded. It must include the complete path to - the directory where <code>LIBFOO_SOURCE</code> can be found.</li> - - <li><code>LIBFOO_DIR</code>: The directory into which the software will - be configured and compiled. Basically, it's a subdirectory of - <code>BUILD_DIR</code> which is created upon decompression of the tarball. - </li> - - <li><code>LIBFOO_BINARY</code>: Software binary name. As said previously, - this is an example for a package with a single binary.</li> - - <li><code>LIBFOO_TARGET_BINARY</code>: The full path of the binary inside - the target filesystem.</li> </ul> - - <p>Lines <a href="#ex2line13">13-14</a> define a target that downloads - the tarball from the remote site to the download directory - (<code>DL_DIR</code>).</p> - - <p>Lines <a href="#ex2line16">16-18</a> define a target and associated - rules that uncompress the downloaded tarball. As you can see, this - target depends on the tarball file so that the previous target (lines - <a href="#ex2line13">13-14</a>) is called before executing the rules of - the current target. Uncompressing is followed by <i>touching</i> a - hidden file to mark the software as having been uncompressed. This trick - is used everywhere in a Buildroot Makefile to split steps (download, - uncompress, configure, compile, install) while still having correct - dependencies.</p> - - <p>Lines <a href="#ex2line20">20-31</a> define a target and associated - rules that configure the software. It depends on the previous target - (the hidden <code>.source</code> file) so that we are sure the software - has been uncompressed. In order to configure the package, it basically - runs the well-known <code>./configure</code> script. As we may be doing - cross-compilation, <code>target</code>, <code>host</code> and - <code>build</code> arguments are given. The prefix is also set to - <code>/usr</code>, not because the software will be installed in - <code>/usr</code> on your host system, but because the software will be - installed in <code> /usr</code> on the target filesystem. Finally it - creates a <code>.configured</code> file to mark the software as - configured.</p> - - <p>Lines <a href="#ex2line33">33-34</a> define a target and a rule that - compile the software. This target will create the binary file in the - compilation directory and depends on the software being already - configured (hence the reference to the <code>.configured</code> file). - It basically runs <code>make</code> inside the source directory.</p> - - <p>Lines <a href="#ex2line36">36-38</a> define a target and associated - rules that install the software inside the target filesystem. They - depend on the binary file in the source directory to make sure the - software has been compiled. They use the <code>install-strip</code> - target of the software <code>Makefile</code> by passing a - <code>DESTDIR</code> argument so that the <code>Makefile</code> doesn't - try to install the software in the host <code>/usr</code> but rather in - the target <code>/usr</code>. After the installation, the - <code>/usr/man </code> directory inside the target filesystem is removed - to save space. </p> - - <p>Line <a href="#ex2line40">40</a> defines the main target of the - software — the one that will eventually be used by the top level - <code>Makefile</code> to download, compile, and then install this - package. This target should first of all depend on all needed - dependencies of the software (in our example, <i>uclibc</i> and - <i>ncurses</i>) and also depend on the final binary. This last dependency - will call all previous dependencies in the correct order.</p> - - <p>Line <a href="#ex2line42">42</a> defines a simple target that only - downloads the code source. This is not used during normal operation of - Buildroot, but is needed if you intend to download all required sources - at once for later offline build. Note that if you add a new package, - providing a <code>libfoo-source</code> target is <i>mandatory</i> to - support users that wish to do offline-builds. Furthermore, it eases - checking if all package-sources are downloadable.</p> - - <p>Lines <a href="#ex2line44">44-46</a> define a simple target to clean - the software build by calling the Makefile with the appropriate options. - The <code>-clean</code> target should run <code>make clean</code> on - $(BUILD_DIR)/package-version and MUST uninstall all files of the package - from $(STAGING_DIR) and from $(TARGET_DIR).</p> - - <p>Lines <a href="#ex2line48">48-49</a> define a simple target to - completely remove the directory in which the software was uncompressed, - configured and compiled. The <code>-dirclean</code> target MUST - completely rm $(BUILD_DIR)/ package-version.</p> - - <p>Lines <a href="#ex2line51">51-58</a> add the target <code>libfoo</code> - to the list of targets to be compiled by Buildroot, by first checking if - the configuration option for this package has been enabled using the - configuration tool. If so, it then "subscribes" this package - to be compiled by adding the package to the TARGETS global variable. - The name added to the TARGETS global variable is the name of this - package's target, as defined on line <a href="#ex2line40">40</a>, which - is used by Buildroot to download, compile, and then install this package. - </p> - - <h3 id="gettext-integration">Gettext integration and interaction with packages</h3> - - <p>Many packages that support internationalization use the gettext - library. Dependencies for this library are fairly complicated and therefore, - deserves some explanation.</p> - - <p>The <i>uClibc</i> C library doesn't implement gettext functionality, - therefore with this C library, a separate gettext must be compiled. On - the other hand, the <i>glibc</i> C library does integrate its own - gettext, and in this case, the separate gettext library should not be - compiled, because it creates various kinds of build failures.</p> - - <p>Additionally, some packages (such as libglib2) do require gettext - unconditionally, while other packages (those who support - <code>--disable-nls</code> in general) only require gettext when locale - support is enabled.</p> - - <p>Therefore, Buildroot defines two configuration options:</p> - - <ul> - <li><code>BR2_NEEDS_GETTEXT</code>, which is true as soon as the - toolchain doesn't provide its own gettext implementation</li> - - <li><code>BR2_NEEDS_GETTEXT_IF_LOCALE</code>, which is true if the - toolchain doesn't provide its own gettext implementation and if locale - support is enabled</li> </ul> - - <p>Therefore, packages that unconditionally need gettext should:</p> - - <ol> - <li>Use <code>select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT</code> - and possibly <code>select BR2_PACKAGE_LIBINTL if BR2_NEEDS_GETTEXT</code>, - if libintl is also needed</li> - - <li>Use <code>$(if $(BR2_NEEDS_GETTEXT),gettext)</code> in the package - <code>DEPENDENCIES</code> variable</li> - </ol> - - <p>Packages that need gettext only when locale support is enabled should: - </p> - - <ol> - <li>Use - <code>select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT_IF_LOCALE</code> - and possibly - <code>select BR2_PACKAGE_LIBINTL if BR2_NEEDS_GETTEXT_IF_LOCALE</code>, - if libintl is also needed</li> - - <li>Use <code>$(if $(BR2_NEEDS_GETTEXT_IF_LOCALE),gettext)</code> in - the package <code>DEPENDENCIES</code> variable</li> - </ol> - - <h3>Conclusion</h3> - - <p>As you can see, adding a software package to Buildroot is simply a - matter of writing a Makefile using an existing example and modifying it - according to the compilation process required by the package.</p> - - <p>If you package software that might be useful for other people, don't - forget to send a patch to Buildroot developers!</p> - - <h2 id="faq">Frequently asked questions</h2> - - <ul> - <li><a href="#faq-boot-hangs">The boot hangs - after <code>Starting network...</code></a></li> - <li><a href="#module-init-tools-doesnt-build">module-init-tools - fails to build with <code>cannot find -lc</code></a></li> - </ul> - - <h3 id="faq-boot-hangs">The boot hangs after <code>Starting - network...</code></h3> - - <p>If the boot process seems to hang after the following messages - (messages not necessarly exactly similar, depending on the list of - packages selected):</p> - - <pre>Freeing init memory: 3972K -Initializing random number generator... done. -Starting network... -Starting dropbear sshd: generating rsa key... generating dsa key... OK</pre> - - <p>then it means that your system is running, but didn't start a - shell on the serial console. In order to have the system start a - shell on your serial console, you have to go in the Buildroot - configuration, <code>System configuration</code>, and modify - <code>Port to run a getty (login prompt) on</code> and - <code>Baudrate to use</code> as appropriate. This will automatically tune - the <code>/etc/inittab</code> file of the generated system so that - a shell starts on the correct serial port.</p> - - <h3 id="module-init-tools-doesnt-build">module-init-tools - fails to build with <code>cannot find -lc</code></h3> - - <p>If the build of <i>module-init-tools</i> for the host fails - with:</p> - - <pre>/usr/bin/ld: cannot find -lc </pre> - - <p>then probably you are running a Fedora (or similar) - distribution, and you should install the <code>glibc-static</code> - package. This is because the <i>module-init-tools</i> build - process wants to link statically against the C library.</p> - - <h2 id="links">Resources</h2> - - <p>To learn more about Buildroot you can visit these websites:</p> - - <ul> - <li><a href="http://www.uclibc.org/">http://www.uclibc.org/</a></li> - <li><a href="http://www.busybox.net/">http://www.busybox.net/</a></li> - </ul> - </div> -</body> -</html> |