![Shawn J. Goff](/assets/img/avatar_default.png)
When ccache is enabled, TARGET_CC is "ccache gcc". Without quotes, when assigning CC=$(TARGET_CC), only "ccache" gets assigned to CC. Signed-off-by: Shawn J. Goff <shawn7400@gmail.com> Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
1820 lines
88 KiB
HTML
1820 lines
88 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>Buildroot - Usage and documentation</title>
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<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
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<link rel="stylesheet" href="stylesheet.css">
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</head>
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<body>
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<div class="main">
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<div class="titre">
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<h1>Buildroot</h1>
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</div>
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<p><a href="http://buildroot.net/">Buildroot</a> usage and documentation
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by Thomas Petazzoni. Contributions from Karsten Kruse, Ned Ludd, Martin
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Herren and others.</p>
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<ul>
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<li><a href="#about">About Buildroot</a></li>
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<li><a href="#download">Obtaining Buildroot</a></li>
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<li><a href="#using">Using Buildroot</a></li>
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<li><a href="#custom_targetfs">Customizing the generated target filesystem</a></li>
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<li><a href="#custom_busybox">Customizing the Busybox configuration</a></li>
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<li><a href="#custom_uclibc">Customizing the uClibc configuration</a></li>
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<li><a href="#custom_linux26">Customizing the Linux kernel configuration</a></li>
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<li><a href="#rebuilding_packages">Understanding how to rebuild packages</a></li>
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<li><a href="#buildroot_innards">How Buildroot works</a></li>
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<li><a href="#using_toolchain">Using the uClibc toolchain outside Buildroot</a></li>
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<li><a href="#external_toolchain">Use an external toolchain</a></li>
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<li><a href="#ccache-support">Using <code>ccache</code> in Buildroot</li>
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<li><a href="#downloaded_packages">Location of downloaded packages</a></li>
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<li><a href="#add_packages">Adding new packages to Buildroot</a></li>
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<li><a href="#board_support">Creating your own board support</a></li>
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<li><a href="#faq">Frequently asked questions</a></li>
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<li><a href="#links">Resources</a></li>
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</ul>
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<h2 id="about">About Buildroot</h2>
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<p>Buildroot is a set of Makefiles and patches that allows you to easily
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generate a cross-compilation toolchain, a root filesystem and a Linux
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kernel image for your target. Buildroot can be used for one, two or all
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of these options, independently.</p>
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<p>Buildroot is useful mainly for people working with embedded systems.
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Embedded systems often use processors that are not the regular x86
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processors everyone is used to having in his PC. They can be PowerPC
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processors, MIPS processors, ARM processors, etc.</p>
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<p>A compilation toolchain is the set of tools that allows you to
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compile code for your system. It consists of a compiler (in our case,
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<code>gcc</code>), binary utils like assembler and linker (in our case,
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<code>binutils</code>) and a C standard library (for example
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<a href="http://www.gnu.org/software/libc/libc.html">GNU Libc</a>,
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<a href="http://www.uclibc.org/">uClibc</a> or
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<a href="http://www.fefe.de/dietlibc/">dietlibc</a>). The system installed
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on your development station certainly already has a compilation
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toolchain that you can use to compile an application that runs on your
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system. If you're using a PC, your compilation toolchain runs on an x86
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processor and generates code for an x86 processor. Under most Linux
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systems, the compilation toolchain uses the GNU libc (glibc) as the C
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standard library. This compilation toolchain is called the "host
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compilation toolchain". The machine on which it is running, and on
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which you're working, is called the "host system". The
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compilation toolchain is provided by your distribution, and Buildroot
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has nothing to do with it (other than using it to build a
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cross-compilation toolchain and other tools that are run on the
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development host).</p>
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<p>As said above, the compilation toolchain that comes with your system
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runs on and generates code for the processor in your host system. As
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your embedded system has a different processor, you need a
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cross-compilation toolchain — a compilation toolchain that runs on
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your host system but generates code for your target system (and target
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processor). For example, if your host system uses x86 and your target
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system uses ARM, the regular compilation toolchain on your host runs on
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x86 and generates code for x86, while the cross-compilation toolchain
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runs on x86 and generates code for ARM.</p>
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<p>Even if your embedded system uses an x86 processor, you might be
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interested in Buildroot for two reasons:</p>
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<ul>
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<li>The compilation toolchain on your host certainly uses the GNU Libc
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which is a complete but huge C standard library. Instead of using GNU
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Libc on your target system, you can use uClibc which is a tiny C
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standard library. If you want to use this C library, then you need a
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compilation toolchain to generate binaries linked with it. Buildroot
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can do that for you.</li>
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<li>Buildroot automates the building of a root filesystem with all needed
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tools like busybox. That makes it much easier than doing it by hand.</li>
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</ul>
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<p>You might wonder why such a tool is needed when you can compile
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<code>gcc</code>, <code>binutils</code>, <code>uClibc</code> and all
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the other tools by hand. Of course doing so is possible but, dealing with
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all of the configure options and problems of every <code>gcc</code> or
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<code>binutils</code> version is very time-consuming and uninteresting.
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Buildroot automates this process through the use of Makefiles and has a
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collection of patches for each <code>gcc</code> and <code>binutils</code>
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version to make them work on most architectures.</p>
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<p>Moreover, Buildroot provides an infrastructure for reproducing
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the build process of your kernel, cross-toolchain, and embedded root
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filesystem. Being able to reproduce the build process will be useful when a
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component needs to be patched or updated or when another person is supposed
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to take over the project.</p>
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<h2 id="download">Obtaining Buildroot</h2>
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<p>Buildroot releases are made approximately every 3
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months. Direct Git access and daily snapshots are also
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available, if you want more bleeding edge.</p>
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<p>Releases are available at
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<a href="http://buildroot.net/downloads/">http://buildroot.net/downloads/</a>.</p>
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<p>The latest snapshot is always available at
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<a href="http://buildroot.net/downloads/snapshots/buildroot-snapshot.tar.bz2">http://buildroot.net/downloads/snapshots/buildroot-snapshot.tar.bz2</a>,
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and previous snapshots are also available at
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<a href="http://buildroot.net/downloads/snapshots/">http://buildroot.net/downloads/snapshots/</a>.</p>
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<p>To download Buildroot using Git, you can simply follow
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the rules described on the "Accessing Git" page
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(<a href= "http://buildroot.net/git.html">http://buildroot.net/git.html</a>)
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of the Buildroot website
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(<a href="http://buildroot.net">http://buildroot.net</a>).
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For the impatient, here's a quick recipe:</p>
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<pre>
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$ git clone git://git.buildroot.net/buildroot
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</pre>
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<h2 id="using">Using Buildroot</h2>
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<p>Buildroot has a nice configuration tool similar to the one you can find
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in the Linux kernel
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(<a href="http://www.kernel.org/">http://www.kernel.org/</a>) or in Busybox
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(<a href="http://www.busybox.org/">http://www.busybox.org/</a>). Note that
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you can (and should) build everything as a normal user. There is no need to
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be root to configure and use Buildroot. The first step is to run the
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configuration assistant:</p>
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<pre>
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$ make menuconfig
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</pre>
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<p>to run the curses-based configurator, or</p>
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<pre>
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$ make xconfig
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</pre>
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<p>or</p>
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<pre>
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$ make gconfig
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</pre>
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<p>to run the Qt or GTK-based configurators.</p>
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<p>All of these "make" commands will need to build a configuration
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utility, so you may need to install "development" packages for relevant
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libraries used by the configuration utilities. On Debian-like systems,
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the <code>libncurses5-dev</code> package is required to use the <i>
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menuconfig</i> interface, <code>libqt4-dev</code> is required to use
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the <i>xconfig</i> interface, and <code>libglib2.0-dev, libgtk2.0-dev
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and libglade2-dev</code> are needed to use the <i>gconfig</i> interface.</p>
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<p>For each menu entry in the configuration tool, you can find associated
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help that describes the purpose of the entry.</p>
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<p>Once everything is configured, the configuration tool generates a
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<code>.config</code> file that contains the description of your
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configuration. It will be used by the Makefiles to do what's needed.</p>
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<p>Let's go:</p>
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<pre>
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$ make
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</pre>
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<p>You <b>should never</b> use <code>make -jN</code> with
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Buildroot: it does not support <i>top-level parallel
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make</i>. Instead, use the <code>BR2_JLEVEL</code> option to tell
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Buildroot to run each package compilation with <code>make
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-jN</code>.</p>
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<p>This command will generally perform the following steps:</p>
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<ul>
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<li>Download source files (as required)</li>
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<li>Configure, build and install the cross-compiling toolchain
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if an internal toolchain is used, or import a toolchain if an
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external toolchain is used</li>
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<li>Build/install selected target packages</li>
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<li>Build a kernel image, if selected</li>
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<li>Build a bootloader image, if selected</li>
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<li>Create a root filesystem in selected formats</li>
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</ul>
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<p>Buildroot output is stored in a single directory, <code>output/</code>.
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This directory contains several subdirectories:</p>
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<ul>
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<li><code>images/</code> where all the images (kernel image,
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bootloader and root filesystem images) are stored.</li>
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<li><code>build/</code> where all the components except for the
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cross-compilation toolchain are built (this includes tools needed to
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run Buildroot on the host and packages compiled for the target). The
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<code>build/</code> directory contains one subdirectory for each of
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these components.</li>
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<li><code>staging/</code> which contains a hierarchy similar to a root
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filesystem hierarchy. This directory contains the installation of the
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cross-compilation toolchain and all the userspace packages selected
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for the target. However, this directory is <i>not</i> intended to be
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the root filesystem for the target: it contains a lot of development
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files, unstripped binaries and libraries that make it far too big for
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an embedded system. These development files are used to compile
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libraries and applications for the target that depend on other
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libraries.</li>
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<li><code>target/</code> which contains <i>almost</i> the complete
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root filesystem for the target: everything needed is present except
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the device files in <code>/dev/</code> (Buildroot can't create them
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because Buildroot doesn't run as root and doesn't want to run as
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root). Therefore, this directory <b>should not be used on your target</b>.
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Instead, you should use one of the images built in the
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<code>images/</code> directory. If you need an extracted image of the
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root filesystem for booting over NFS, then use the tarball image
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generated in <code>images/</code> and extract it as root.<br/>Compared
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to <code>staging/</code>, <code>target/</code> contains only the
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files and libraries needed to run the selected target applications:
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the development files (headers, etc.) are not present, unless the
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<code>development files in target filesystem</code> option is selected.
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</li>
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<li><code>host/</code> contains the installation of tools compiled for
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the host that are needed for the proper execution of Buildroot,
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including the cross-compilation toolchain.</li>
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<li><code>toolchain/</code> contains the build directories for the
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various components of the cross-compilation toolchain.</li>
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</ul>
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<h3 id="offline_builds">Offline builds</h3>
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<p>If you intend to do an offline build and just want to download
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all sources that you previously selected in the configurator
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(<i>menuconfig</i>, <i>xconfig</i> or <i>gconfig</i>), then issue:</p>
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<pre>
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$ make source
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</pre>
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<p>You can now disconnect or copy the content of your <code>dl</code>
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directory to the build-host.</p>
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<h3 id="building_out_of_tree">Building out-of-tree</h3>
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<p>Buildroot supports building out of tree with a syntax similar to the
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Linux kernel. To use it, add O=<directory> to the make command
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line:</p>
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<pre>
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$ make O=/tmp/build
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</pre>
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<p>Or:</p>
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<pre>
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$ cd /tmp/build; make O=$PWD -C path/to/buildroot
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</pre>
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<p>All the output files will be located under <code>/tmp/build</code>.</p>
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<p>When using out-of-tree builds, the Buildroot <code>.config</code> and
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temporary files are also stored in the output directory. This means that
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you can safely run multiple builds in parallel using the same source
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tree as long as they use unique output directories.</p>
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<p>For ease of use, Buildroot generates a Makefile wrapper in the output
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directory - So after the first run, you no longer need to pass
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<code>O=..</code> and <code>-C ..</code>, simply run (in the output
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directory):</p>
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<pre>
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$ make <target>
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</pre>
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<h3 id="environment_variables">Environment variables</h3>
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<p>Buildroot also honors some environment variables, when they are passed
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to <code>make</code> or set in the environment:</p>
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<ul>
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<li><code>HOSTCXX</code>, the host C++ compiler to use</li>
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<li><code>HOSTCC</code>, the host C compiler to use</li>
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<li><code>UCLIBC_CONFIG_FILE=<path/to/.config></code>, path to
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the uClibc configuration file, used to compile uClibc, if an
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internal toolchain is being built</li>
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<li><code>BUSYBOX_CONFIG_FILE=<path/to/.config></code>, path to
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the Busybox configuration file</li>
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<li><code>BUILDROOT_DL_DIR</code> to override the directory in which
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Buildroot stores/retrieves downloaded files</li>
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</ul>
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<p>An example that uses config files located in the toplevel directory and
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in your $HOME:</p>
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<pre>
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$ make UCLIBC_CONFIG_FILE=uClibc.config BUSYBOX_CONFIG_FILE=$HOME/bb.config
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</pre>
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<p>If you want to use a compiler other than the default <code>gcc</code>
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or <code>g++</code> for building helper-binaries on your host, then do</p>
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<pre>
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$ make HOSTCXX=g++-4.3-HEAD HOSTCC=gcc-4.3-HEAD
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</pre>
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<h2 id="custom_targetfs">Customizing the generated target filesystem</h2>
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<p>There are a few ways to customize the resulting target filesystem:</p>
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<ul>
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<li>Customize the target filesystem directly and rebuild the image.
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The target filesystem is available under <code>output/target/</code>.
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You can simply make your changes here and run make afterwards —
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this will rebuild the target filesystem image. This method allows you
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to do anything to the target filesystem, but if you decide to
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completely rebuild your toolchain and tools, these changes will be
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lost.</li>
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<li>Create your own <i>target skeleton</i>. You can start with
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the default skeleton available under <code>fs/skeleton</code>
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and then customize it to suit your
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needs. The <code>BR2_ROOTFS_SKELETON_CUSTOM</code>
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and <code>BR2_ROOTFS_SKELETON_CUSTOM_PATH</code> will allow you
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to specify the location of your custom skeleton. At build time,
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the contents of the skeleton are copied to output/target before
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any package installation.</li>
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<li>In the Buildroot configuration, you can specify the path to a
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post-build script, that gets called <i>after</i> Buildroot builds all
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the selected software, but <i>before</i> the rootfs packages are
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assembled. The destination root filesystem folder is given as the
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first argument to this script, and this script can then be used to
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copy programs, static data or any other needed file to your target
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filesystem.<br/>You should, however, use this feature with care.
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Whenever you find that a certain package generates wrong or unneeded
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files, you should fix that package rather than work around it with a
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post-build cleanup script.</li>
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<li>A special package, <i>customize</i>, stored in
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<code>package/customize</code> can be used. You can put all the
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files that you want to see in the final target root filesystem
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in <code>package/customize/source</code>, and then enable this
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special package in the configuration system.</li>
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</ul>
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<h2 id="custom_busybox">Customizing the Busybox configuration</h2>
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<p><a href="http://www.busybox.net/">Busybox</a> is very configurable,
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and you may want to customize it. You can follow these simple steps to
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do so. This method isn't optimal, but it's simple, and it works:</p>
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<ol>
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<li>Do an initial compilation of Buildroot, with busybox, without
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trying to customize it.</li>
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<li>Invoke <code>make busybox-menuconfig</code>.
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The nice configuration tool appears, and you can
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customize everything.</li>
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<li>Run the compilation of Buildroot again.</li>
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</ol>
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<p>Otherwise, you can simply change the
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<code>package/busybox/busybox-<version>.config</code> file, if you
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know the options you want to change, without using the configuration tool.
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</p>
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<p>If you want to use an existing config file for busybox, then see
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section <a href="#environment_variables">environment variables</a>.</p>
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<h2 id="custom_uclibc">Customizing the uClibc configuration</h2>
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<p>Just like <a href="#custom_busybox">BusyBox</a>,
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<a href="http://www.uclibc.org/">uClibc</a> offers a lot of
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configuration options. They allow you to select various
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functionalities depending on your needs and limitations.</p>
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<p>The easiest way to modify the configuration of uClibc is to
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follow these steps:</p>
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<ol>
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<li>Do an initial compilation of Buildroot without trying to
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customize uClibc.</li>
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<li>Invoke <code>make uclibc-menuconfig</code>.
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The nice configuration assistant, similar to
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the one used in the Linux kernel or Buildroot, appears. Make
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your configuration changes as appropriate.</li>
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<li>Copy the <code>$(O)/toolchain/uclibc-VERSION/.config</code>
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file to a different place
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(like <code>toolchain/uClibc/uClibc-myconfig.config</code>,
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or <code>board/mymanufacturer/myboard/uClibc.config</code>) and
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adjust the uClibc configuration (configuration
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option <code>BR2_UCLIBC_CONFIG</code>) to use this configuration
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instead of the default one.</li>
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<li>Run the compilation of Buildroot again.</li>
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</ol>
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<p>Otherwise, you can simply change
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<code>toolchain/uClibc/uClibc.config</code>, without running the
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configuration assistant.</p>
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<p>If you want to use an existing config file for uclibc, then see
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section <a href="#environment_variables">environment variables</a>.</p>
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<h2 id="custom_linux26">Customizing the Linux kernel configuration</h2>
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<p>The Linux kernel configuration can be customized just like
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<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>
|