653 lines
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653 lines
28 KiB
HTML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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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=iso-8859-1" />
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<link rel="stylesheet" type="text/css" 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>Usage and documentation by Thomas Petazzoni. Contributions from
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Karsten Kruse, Ned Ludd, Martin Herren.</p>
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<p><small>$LastChangedDate$</small></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 target filesystem</a></li>
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<li><a href="#custom_busybox">Customizing the Busybox
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configuration</a></li>
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<li><a href="#custom_uclibc">Customizing the uClibc
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configuration</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</a></li>
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<li><a href="#toolchain_standalone">Using the uClibc toolchain
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outside of Buildroot</a></li>
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<li><a href="#downloaded_packages">Location of downloaded packages</a></li>
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<li><a href="#add_software">Extending Buildroot with more
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Software</a></li>
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<li><a href="#links">Resources</a></li>
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</ul>
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<h2><a name="about" id="about"></a>About Buildroot</h2>
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<p>Buildroot is a set of Makefiles and patches that allows to easily
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generate both a cross-compilation toolchain and a root filesystem for your
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target. The cross-compilation toolchain uses uClibc (<a href=
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"http://www.uclibc.org/">http://www.uclibc.org/</a>), a tiny C standard
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library.</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 have on his PC. It 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 to
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compile code for your system. It consists of a compiler (in our
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case, <code>gcc</code>), binary utils like assembler and linker
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(in our case, <code>binutils</code>) and a C standard library (for
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example <a href="http://www.gnu.org/software/libc/libc.html">GNU
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Libc</a>, <a href="http://www.uclibc.org/">uClibc</a> or <a
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href="http://www.fefe.de/dietlibc/">dietlibc</a>). The system
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installed on your development station certainly already has a
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compilation toolchain that you can use to compile application that
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runs on your system. If you're using a PC, your compilation
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toolchain runs on an x86 processor and generates code for a x86
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processor. Under most Linux systems, the compilation toolchain
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uses the GNU libc as C standard library. This compilation
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toolchain is called the "host compilation toolchain", and more
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generally, the machine on which it is running, and on which you're
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working is called the "host system". The compilation toolchain is
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provided by your distribution, and Buildroot has nothing to do
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with it.</p>
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<p>As said above, the compilation toolchain that comes with your system
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runs and generates code for the processor of your host system. As your
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embedded system has a different processor, you need a cross-compilation
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toolchain: it's a compilation toolchain that runs on your host system but
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that generates code for your target system (and target processor). For
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example, if your host system uses x86 and your target system uses ARM, the
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regular compilation toolchain of your host runs on x86 and generates code
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for x86, while the cross-compilation toolchain runs on x86 and generates
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code for ARM.</p>
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<p>Even if your embedded system uses a x86 processor, you might interested
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in Buildroot, for two reasons:</p>
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<ul>
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<li>The compilation toolchain of 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 standard
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library. If you want to use this C library, then you need a compilation
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toolchain to generate binaries linked with it. Buildroot can do it for
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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. It 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>, uClibc and all the tools by hand.
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Of course, doing so is possible. But dealing with all configure options,
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with all problems of every <code>gcc</code> or <code>binutils</code>
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version it very time-consuming and uninteresting. Buildroot automates this
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process through the use of Makefiles, and has a collection of patches for
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each <code>gcc</code> and <code>binutils</code> version to make them work
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on most architectures.</p>
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<h2><a name="download" id="download"></a>Obtaining Buildroot</h2>
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<p>Buildroot is available as daily SVN snapshots or directly using
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SVN.</p>
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<p>The latest snapshot is always available at <a
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href="http://buildroot.uclibc.org/downloads/snapshots/buildroot-snapshot.tar.bz2">http://buildroot.uclibc.org/downloads/snapshots/buildroot-snapshot.tar.bz2</a>,
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and previous snapshots are also available at <a
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href="http://buildroot.uclibc.org/downloads/snapshots/">http://buildroot.uclibc.org/downloads/snapshots/</a>.</p>
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<p>To download Buildroot using SVN, you can simply follow
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the rules described on the "Accessing SVN"-page (<a href=
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"http://buildroot.uclibc.org/subversion.html">http://buildroot.uclibc.org/subversion.html</a>)
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of the uClibc buildroot website (<a href=
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"http://buildroot.uclibc.org">http://buildroot.uclibc.org</a>), and download the
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<code>buildroot</code> SVN module. For the impatient, here's a quick
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recipe:</p>
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<pre>
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$ svn co svn://uclibc.org/trunk/buildroot
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</pre>
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<h2><a name="using" id="using"></a>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 (<a href=
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"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 run everything as a normal user. There is no need to be root to
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configure and use Buildroot. The first step is to run the configuration
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assistant:</p>
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<pre>
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$ make menuconfig
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</pre>
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<p>For each entry of the configuration tool, you can find associated help
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that describes the purpose of the entry.</p>
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<p>Once everything is configured, the configuration tool has generated 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>This command will download, configure and compile all the selected
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tools, and finally generate a target filesystem. The target filesystem will
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be named <code>root_fs_ARCH.EXT</code> where <code>ARCH</code> is your
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architecture and <code>EXT</code> depends on the type of target filesystem
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selected in the <code>Target options</code> section of the configuration
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tool.</p>
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<h2><a name="custom_targetfs" id="custom_targetfs"></a>Customizing the
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target filesystem</h2>
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<p>There are two 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. The
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target filesystem is available under <code>build_ARCH/root/</code> where
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<code>ARCH</code> is the chosen target architecture. You can simply make
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your changes here, and run make afterwards, which will rebuild the target
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filesystem image. This method allows to do everything on the target
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filesystem, but if you decide to completely rebuild your toolchain and
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tools, these changes will be lost.</li>
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<li>Customize the target filesystem skeleton, available under
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<code>target/generic/target_skeleton/</code>. You can customize
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configuration files or other stuff here. However, the full file hierarchy
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is not yet present, because it's created during the compilation process.
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So you can't do everything on this target filesystem skeleton, but
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changes to it remain even if you completely rebuild the cross-compilation
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toolchain and the tools.<br />
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You can also customize the <code>target/generic/device_table.txt</code>
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file which is used by the tools that generate the target filesystem image
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to properly set permissions and create device nodes. The
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<code>target/generic/skel.tar.gz</code> file contains the main
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directories of a root filesystem and there is no obvious reason for which
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it should be changed. These main directories are in an tarball inside of
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inside the skeleton because it contains symlinks that would be broken
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otherwise.<br />
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These customizations are deployed into <code>build_ARCH/root/</code> just
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before the actual image is made. So simply rebuilding the image by running
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make should propogate any new changes to the image.</li>
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</ul>
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<h2><a name="custom_busybox" id="custom_busybox"></a>Customizing the
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Busybox configuration</h2>
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<p>Busybox is very configurable, and you may want to customize it. You can
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follow these simple steps to do it. It's not an optimal way, but it's
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simple and it works.</p>
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<ol>
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<li>Make a first compilation of buildroot with busybox without trying to
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customize it.</li>
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<li>Go into <code>build_ARCH/busybox/</code> and run <code>make
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menuconfig</code>. The nice configuration tool appears and you can
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customize everything.</li>
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<li>Copy the <code>.config</code> file to
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<code>package/busybox/busybox.config</code> so that your customized
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configuration will remains even if you remove the cross-compilation
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toolchain.</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.config</code> file if you know the options
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you want to change without using the configuration tool.</p>
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<h2><a name="custom_uclibc" id="custom_uclibc"></a>Customizing the uClibc
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configuration</h2>
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<p>Just like <a href="#custom_busybox">BusyBox</a>, <a
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href="http://www.uclibc.org/">uClibc</a> offers a lot of
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configuration options. They allow 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>Make a first compilation of buildroot without trying to
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customize uClibc.</li>
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<li>Go into the directory
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<code>toolchain_build_ARCH/uClibc/</code> and run <code>make
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menuconfig</code>. The nice configuration assistant, similar to
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the one used in the Linux Kernel or in Buildroot appears. Make
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your configuration as appropriate.</li>
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<li>Copy the <code>.config</code> file to
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<code>toolchain/uClibc/uClibc.config</code> or
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<code>toolchain/uClibc/uClibc.config-locale</code>. The former
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is used if you haven't selected locale support in Buildroot
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configuration, and the latter is used if you have selected
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locale support.</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> or
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<code>toolchain/uClibc/uClibc.config-locale</code> without running
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the configuration assistant.</p>
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<h2><a name="buildroot_innards" id="buildroot_innards"></a>How Buildroot
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works</h2>
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<p>As said above, Buildroot is basically a set of Makefiles that download,
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configure and compiles software with the correct options. It also includes
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some patches for various software, mainly the ones involved in the
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cross-compilation tool chain (<code>gcc</code>, <code>binutils</code> and
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uClibc).</p>
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<p>There is basically one Makefile per software, and they are named with
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the <code>.mk</code> extension. Makefiles are split into three
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sections:</p>
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<ul>
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<li><b>package</b> (in the <code>package/</code> directory) contains the
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Makefiles and associated files for all user-space tools that Buildroot
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can compile and add to the target root filesystem. There is one
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sub-directory per tool.</li>
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<li><b>toolchain</b> (in the <code>toolchain/</code> directory) contains
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the Makefiles and associated files for all software related to the
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cross-compilation toolchain : <code>binutils</code>, <code>ccache</code>,
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<code>gcc</code>, <code>gdb</code>, <code>kernel-headers</code> and
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<code>uClibc</code>.</li>
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<li><b>target</b> (in the <code>target</code> directory) contains the
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Makefiles and associated files for software related to the generation of
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the target root filesystem image. Four types of filesystems are supported
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: ext2, jffs2, cramfs and squashfs. For each of them, there's a
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sub-directory with the required files. There is also a
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<code>default/</code> directory that contains the target filesystem
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skeleton.</li>
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</ul>
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<p>Each directory contains at least 2 files :</p>
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<ul>
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<li><code>something.mk</code> is the Makefile that downloads, configures,
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compiles and installs the software <code>something</code>.</li>
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<li><code>Config.in</code> is a part of the configuration tool
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description file. It describes the option related to the current
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software.</li>
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</ul>
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<p>The main Makefile do the job through the following steps (once the
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configuration is done):</p>
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<ol>
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<li>Create the download directory (<code>dl/</code> by default). This is
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where the tarballs will be downloaded. It is interesting to know that the
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tarballs are in this directory because it may be useful to save them
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somewhere to avoid further downloads.</li>
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<li>Create the build directory (<code>build_ARCH/</code> by default,
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where <code>ARCH</code> is your architecture). This is where all
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user-space tools while be compiled.</li>
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<li>Create the toolchain build directory
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(<code>toolchain_build_ARCH/</code> by default, where <code>ARCH</code>
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is your architecture). This is where the cross compilation toolchain will
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be compiled.</li>
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<li>Setup the staging directory (<code>build_ARCH/staging_dir/</code> by
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default). This is where the cross-compilation toolchain will be
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installed. If you want to use the same cross-compilation toolchain for
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other purposes, such as compiling third-party applications, you can add
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<code>build_ARCH/staging_dir/bin</code> to your PATH, and then use
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<code>arch-linux-gcc</code> to compile your application. In order to
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setup this staging directory, it first removes it, and then it creates
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various subdirectories and symlinks inside it.</li>
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<li>Create the target directory (<code>build_ARCH/root/</code> by
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default) and the target filesystem skeleton. This directory will contain
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the final root filesystem. To setup it up, it first deletes it, then it
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uncompress the <code>target/generic/skel.tar.gz</code> file to create the
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main subdirectories and symlinks, copies the skeleton available in
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<code>target/generic/target_skeleton</code> and then removes useless
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<code>.svn/</code> directories.</li>
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<li>Add the <code>TARGETS</code> dependency. This should generally check
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if the configuration option for this package is enabled, and if so then
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"subscribe" this package to be compiled by adding it to the TARGETS
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global variable.</li>
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</ol>
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<h2><a name="using_toolchain" id="using_toolchain"></a>Using the
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uClibc toolchain</h2>
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<p>You may want to compile your own programs or other software
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that are not packaged in Buildroot. In order to do this, you can
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use the toolchain that was generated by Buildroot.</p>
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<p>The toolchain generated by Buildroot by default is located in
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<code>build_ARCH/staging_dir/</code>. The simplest way to use it
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is to add <code>build_ARCH/staging_dir/bin/</code> to your PATH
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environnement variable, and then to use
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<code>arch-linux-gcc</code>, <code>arch-linux-objdump</code>,
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<code>arch-linux-ld</code>, etc.</p>
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<p>For example, you may add the following to your
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<code>.bashrc</code> (considering you're building for the MIPS
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architecture and that Buildroot is located in
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<code>~/buildroot/</code>) :</p>
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<pre>
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export PATH=$PATH:~/buildroot/build_mips/staging_dir/bin/
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</pre>
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<p>Then you can simply do :</p>
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<pre>
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mips-linux-gcc -o foo foo.c
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</pre>
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<p><b>Important</b> : do not try to move the toolchain to an other
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directory, it won't work. There are some hard-coded paths in the
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<i>gcc</i> configuration. If the default toolchain directory
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doesn't suit your needs, please refer to the <a
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href="#toolchain_standalone">Using the uClibc toolchain outside of
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buildroot</a> section.</p>
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<h2><a name="toolchain_standalone" id="toolchain_standalone"></a>Using the
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uClibc toolchain outside of buildroot</h2>
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<p>By default, the cross-compilation toolchain is generated inside
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<code>build_ARCH/staging_dir/</code>. But sometimes, it may be useful to
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install it somewhere else, so that it can be used to compile other programs
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or by other users. Moving the <code>build_ARCH/staging_dir/</code>
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directory elsewhere is <b>not possible</b>, because they are some hardcoded
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paths in the toolchain configuration.</p>
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<p>If you want to use the generated toolchain for other purposes,
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you can configure Buildroot to generate it elsewhere using the
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option of the configuration tool : <code>Build options ->
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Toolchain and header file location</code>, which defaults to
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<code>$(BUILD_DIR)/staging_dir/</code>.</p>
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<h2><a name="downloaded_packages"
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id="downloaded_packages"></a>Location of downloaded packages</h2>
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<p>It might be useful to know that the various tarballs that are
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downloaded by the <i>Makefiles</i> are all stored in the
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<code>DL_DIR</code> which by default is the <code>dl</code>
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directory. It's useful for example if you want to keep a complete
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version of Buildroot which is know to be working with the
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associated tarballs. This will allow you to regenerate the
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toolchain and the target filesystem with exactly the same
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versions.</p>
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<h2><a name="add_software" id="add_software"></a>Extending Buildroot with
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more software</h2>
|
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<p>This section will only consider the case in which you want to
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add user-space software.</p>
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<h3>Package directory</h3>
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<p>First of all, create a directory under the <code>package</code>
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directory for your software, for example <code>foo</code>.</p>
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<h3><code>Config.in</code> file</h3>
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<p>Then, create a file named <code>Config.in</code>. This file
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will contain the portion of options description related to our
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<code>foo</code> software that will be used and displayed in the
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configuration tool. It should basically contain :</p>
|
|
|
|
<pre>
|
|
config BR2_PACKAGE_FOO
|
|
bool "foo"
|
|
default n
|
|
help
|
|
This is a comment that explains what foo is.
|
|
</pre>
|
|
|
|
<p>Of course, you can add other options to configure particular
|
|
things in your software.</p>
|
|
|
|
<h3>The real <i>Makefile</i></h3>
|
|
|
|
<p>Finally, here's the hardest part. Create a file named
|
|
<code>foo.mk</code>. It will contain the <i>Makefile</i> rules that
|
|
are in charge of downloading, configuring, compiling and installing
|
|
the software. Below is an example that we will comment
|
|
afterwards.</p>
|
|
|
|
<pre>
|
|
1 #############################################################
|
|
2 #
|
|
3 # foo
|
|
4 #
|
|
5 #############################################################
|
|
6 FOO_VERSION:=1.0
|
|
7 FOO_SOURCE:=foo-$(FOO_VERSION).tar.gz
|
|
8 FOO_SITE:=http://www.foosoftware.org/downloads
|
|
9 FOO_DIR:=$(BUILD_DIR)/foo-$(FOO_VERSION)
|
|
10 FOO_BINARY:=foo
|
|
11 FOO_TARGET_BINARY:=usr/bin/foo
|
|
12
|
|
13 $(DL_DIR)/$(FOO_SOURCE):
|
|
14 $(WGET) -P $(DL_DIR) $(FOO_SITE)/$(FOO_SOURCE)
|
|
15
|
|
16 $(FOO_DIR)/.source: $(DL_DIR)/$(FOO_SOURCE)
|
|
17 $(ZCAT) $(DL_DIR)/$(FOO_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) -
|
|
18 touch $@
|
|
19
|
|
20 $(FOO_DIR)/.configured: $(FOO_DIR)/.source
|
|
21 (cd $(FOO_DIR); rm -rf config.cache ; \
|
|
22 $(TARGET_CONFIGURE_OPTS) \
|
|
23 CFLAGS="$(TARGET_CFLAGS)" \
|
|
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
|
|
33 $(FOO_DIR)/$(FOO_BINARY): $(FOO_DIR)/.configured
|
|
34 $(MAKE) CC=$(TARGET_CC) -C $(FOO_DIR)
|
|
35
|
|
36 $(TARGET_DIR)/$(FOO_TARGET_BINARY): $(FOO_DIR)/$(FOO_BINARY)
|
|
37 $(MAKE) prefix=$(TARGET_DIR)/usr -C $(FOO_DIR) install
|
|
38 rm -Rf $(TARGET_DIR)/usr/man
|
|
39
|
|
40 foo: uclibc ncurses $(TARGET_DIR)/$(FOO_TARGET_BINARY)
|
|
41
|
|
42 foo-source: $(DL_DIR)/$(FOO_SOURCE)
|
|
43
|
|
44 foo-clean:
|
|
45 $(MAKE) prefix=$(TARGET_DIR)/usr -C $(FOO_DIR) uninstall
|
|
46 -$(MAKE) -C $(FOO_DIR) clean
|
|
47
|
|
48 foo-dirclean:
|
|
49 rm -rf $(FOO_DIR)
|
|
50
|
|
51 #############################################################
|
|
52 #
|
|
53 # Toplevel Makefile options
|
|
54 #
|
|
55 #############################################################
|
|
56 ifeq ($(strip $(BR2_PACKAGE_FOO)),y)
|
|
57 TARGETS+=foo
|
|
58 endif
|
|
|
|
</pre>
|
|
|
|
<p>First of all, this <i>Makefile</i> example works for a single
|
|
binary software. For other software such as libraries or more
|
|
complex stuff with multiple binaries, it should be adapted. Look at
|
|
the other <code>*.mk</code> files in the <code>package</code>
|
|
directory.</p>
|
|
|
|
<p>At lines 6-11, a couple of useful variables are defined :</p>
|
|
|
|
<ul>
|
|
|
|
<li><code>FOO_VERSION</code> : The version of <i>foo</i> that
|
|
should be downloaded.</li>
|
|
|
|
<li><code>FOO_SOURCE</code> : The name of the tarball of
|
|
<i>foo</i> on the download website of FTP site. As you can see
|
|
<code>FOO_VERSION</code> is used.</li>
|
|
|
|
<li><code>FOO_SITE</code> : The HTTP or FTP site from which
|
|
<i>foo</i> archive is downloaded. It must include the complete
|
|
path to the directory where <code>FOO_SOURCE</code> can be
|
|
found.</li>
|
|
|
|
<li><code>FOO_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>FOO_BINARY</code> : Software binary name. As said
|
|
previously, this is an example for a single binary software.</li>
|
|
|
|
<li><code>FOO_TARGET_BINARY</code> : The full path of the binary
|
|
inside the target filesystem.</li>
|
|
|
|
</ul>
|
|
|
|
<p>Lines 13-14 defines a target that downloads the tarball from
|
|
the remote site to the download directory
|
|
(<code>DL_DIR</code>).</p>
|
|
|
|
<p>Lines 16-18 defines 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 (line
|
|
13-14) is called before executing the rules of the current
|
|
target. Uncompressing is followed by <i>touching</i> a hidden file
|
|
to mark the software has having been uncompressed. This trick is
|
|
used everywhere in Buildroot <i>Makefile</i> to split steps
|
|
(download, uncompress, configure, compile, install) while still
|
|
having correct dependencies.</p>
|
|
|
|
<p>Lines 20-31 defines a target and associated rules that
|
|
configures 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 it, 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 in the target
|
|
filesystem. Finally it creates a <code>.configured</code> file to
|
|
mark the software as configured.</p>
|
|
|
|
<p>Lines 33-34 defines a target and a rule that compiles 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 36-38 defines a target and associated rules that install
|
|
the software inside the target filesystem. It depends on the
|
|
binary file in the source directory, to make sure the software has
|
|
been compiled. It uses the <code>install</code> target of the
|
|
software <code>Makefile</code> by passing a <code>prefix</code>
|
|
argument, so that the <code>Makefile</code> doesn't try to install
|
|
the software inside host <code>/usr</code> but inside 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 40 defines the main target of the software, the one
|
|
that will be eventually be used by the top level
|
|
<code>Makefile</code> to download, compile, and then install
|
|
this package. This target should first of all depends on all
|
|
needed dependecies 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 42 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>foo-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 44-46 define a simple target to clean the software build
|
|
by calling the <i>Makefiles</i> with the appropriate option.<br>
|
|
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 48-49 define a simple target to completely remove the
|
|
directory in which the software was uncompressed, configured and
|
|
compiled. This target MUST completely rm $(BUILD_DIR)/package-version.</p>
|
|
|
|
<p>Lines 51-58 adds the target <code>foo</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, and if so then "subscribes"
|
|
this package to be compiled by adding it 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 40, which is used by Buildroot to download, compile, and
|
|
then install this package.</p>
|
|
|
|
|
|
<h3>Conclusion</h3>
|
|
|
|
<p>As you can see, adding a software to buildroot is simply a
|
|
matter of writing a <i>Makefile</i> using an already existing
|
|
example and to modify it according to the compilation process of
|
|
the software.</p>
|
|
|
|
<p>If you package software that might be useful for other persons,
|
|
don't forget to send a patch to Buildroot developers !</p>
|
|
|
|
<h2><a name="links" id="links"></a>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>
|