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update buildroot documentation 

SVN-Revision: 406
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Felix Fietkau 2005-03-21 11:42:30 +00:00
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@ -4,7 +4,7 @@
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Buildroot - Usage and documentation</title>
<title>OpenWrt Buildroot - Usage and documentation</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<link rel="stylesheet" type="text/css" href="stylesheet.css" />
</head>
@ -12,46 +12,41 @@
<body>
<div class="main">
<div class="titre">
<h1>Buildroot</h1>
<h1>OpenWrt Buildroot</h1>
</div>
<p>Usage and documentation by Thomas Petazzoni. Contributions from
Karsten Kruse, Ned Ludd, Martin Herren.</p>
<p>Usage and documentation by Felix Fietkau, based on uClibc Buildroot
documentation by Thomas Petazzoni. Contributions from Karsten Kruse,
Ned Ludd, Martin Herren.</p>
<p><small>Last modification : $Id$</small></p>
<ul>
<li><a href="#about">About Buildroot</a></li>
<li><a href="#download">Obtaining Buildroot</a></li>
<li><a href="#using">Using Buildroot</a></li>
<li><a href="#about">About OpenWrt Buildroot</a></li>
<li><a href="#download">Obtaining OpenWrt Buildroot</a></li>
<li><a href="#using">Using OpenWrt Buildroot</a></li>
<li><a href="#custom_targetfs">Customizing the target filesystem</a></li>
<li><a href="#custom_busybox">Customizing the Busybox
configuration</a></li>
<li><a href="#custom_uclibc">Customizing the uClibc
configuration</a></li>
<li><a href="#buildroot_innards">How Buildroot works</a></li>
<li><a href="#buildroot_innards">How OpenWrt Buildroot works</a></li>
<li><a href="#using_toolchain">Using the uClibc toolchain</a></li>
<li><a href="#toolchain_standalone">Using the uClibc toolchain
outside of Buildroot</a></li>
<li><a href="#downloaded_packages">Location of downloaded packages</a></li>
<li><a href="#add_software">Extending Buildroot with more
Software</a></li>
<li><a href="#add_software">Extending OpenWrt with more Software</a></li>
<li><a href="#links">Ressources</a></li>
</ul>
<h2><a name="about" id="about"></a>About Buildroot</h2>
<h2><a name="about" id="about"></a>About OpenWrt Buildroot</h2>
<p>Buildroot is a set of Makefiles and patches that allows to easily
<p>OpenWrt Buildroot is a set of Makefiles and patches that allows to easily
generate both a cross-compilation toolchain and a root filesystem for your
target. The cross-compilation toolchain uses uClibc (<a href=
Wireless Router. The cross-compilation toolchain uses uClibc (<a href=
"http://www.uclibc.org/">http://www.uclibc.org/</a>), a tiny C standard
library.</p>
<p>Buildroot is useful mainly for people working with embedded systems.
Embedded systems often use processors that are not the regular x86
processors everyone is used to have on his PC. It can be PowerPC
processors, MIPS processors, ARM processors, etc.</p>
<p>A compilation toolchain is the set of tools that allows to
compile code for your system. It consists of a compiler (in our
case, <code>gcc</code>), binary utils like assembler and linker
@ -68,7 +63,7 @@
toolchain is called the "host compilation toolchain", and more
generally, the machine on which it is running, and on which you're
working is called the "host system". The compilation toolchain is
provided by your distribution, and Buildroot has nothing to do
provided by your distribution, and OpenWrt Buildroot has nothing to do
with it.</p>
<p>As said above, the compilation toolchain that comes with your system
@ -76,66 +71,34 @@
embedded system has a different processor, you need a cross-compilation
toolchain: it's a compilation toolchain that runs on your host system but
that generates code for your target system (and target processor). For
example, if your host system uses x86 and your target system uses ARM, the
example, if your host system uses x86 and your target system uses MIPS, the
regular compilation toolchain of your host runs on x86 and generates code
for x86, while the cross-compilation toolchain runs on x86 and generates
code for ARM.</p>
<p>Even if your embedded system uses a x86 processor, you might interested
in Buildroot, for two reasons:</p>
<ul>
<li>The compilation toolchain of your host certainly uses the GNU Libc
which is a complete but huge C standard library. Instead of using GNU
Libc on your target system, you can use uClibc which is a tiny C standard
library. If you want to use this C library, then you need a compilation
toolchain to generate binaries linked with it. Buildroot can do it for
you.</li>
<li>Buildroot automates the building of a root filesystem with all needed
tools like busybox. It makes it much easier than doing it by hand.</li>
</ul>
code for MIPS.</p>
<p>You might wonder why such a tool is needed when you can compile
<code>gcc</code>, <code>binutils</code>, uClibc and all the tools by hand.
Of course, doing so is possible. But dealing with all configure options,
with all problems of every <code>gcc</code> or <code>binutils</code>
version it very time-consuming and uninteresting. Buildroot automates this
version it very time-consuming and uninteresting. OpenWrt Buildroot automates this
process through the use of Makefiles, and has a collection of patches for
each <code>gcc</code> and <code>binutils</code> version to make them work
on most architectures.</p>
on the MIPS architecture of most Broadcom based Wireless Routers.</p>
<h2><a name="download" id="download"></a>Obtaining Buildroot</h2>
<h2><a name="download" id="download"></a>Obtaining OpenWrt Buildroot</h2>
<p>Buildroot is available as daily CVS snapshots or directly using
CVS.</p>
<p>OpenWrt Buildroot is currently available as experimental snapshots</p>
<p>The latest snapshot is always available at <a
href="http://uclibc.org/downloads/snapshots/buildroot-snapshot.tar.bz2">http://uclibc.org/downloads/snapshots/buildroot-snapshot.tar.bz2</a>,
and previous snapshots are also available at <a
href="http://uclibc.org/downloads/snapshots/">http://uclibc.org/downloads/snapshots/</a>.</p>
href="http://openwrt.org/downloads/experimental/">http://openwrt.org/downloads/experimental/</a>,
<p>To download Buildroot using CVS, you can simply follow
the rules described on the "Accessing CVS"-page (<a href=
"http://www.uclibc.org/cvs_anon.html">http://www.uclibc.org/cvs_anon.html</a>)
of the uClibc website (<a href=
"http://www.uclibc.org">http://www.uclibc.org</a>), and download the
<code>buildroot</code> CVS module. For the impatient, here's a quick
recipe:</p>
<h2><a name="using" id="using"></a>Using OpenWrt Buildroot</h2>
<pre>
$ cvs -d:pserver:anonymous@uclibc.org:/var/cvs login
$ cvs -z3 -d:pserver:anonymous@uclibc.org:/var/cvs co buildroot
</pre>
<h2><a name="using" id="using"></a>Using Buildroot</h2>
<p>Buildroot has a nice configuration tool similar to the one you can find
in the Linux Kernel (<a href=
"http://www.kernel.org/">http://www.kernel.org/</a>) or in Busybox
(<a href="http://www.busybox.org/">http://www.busybox.org/</a>). Note that
you can run everything as a normal user. There is no need to be root to
configure and use Buildroot. The first step is to run the configuration
<p>OpenWrt Buildroot has a nice configuration tool similar to the one you can find
in the Linux Kernel (<a href="http://www.kernel.org/">http://www.kernel.org/</a>)
or in Busybox (<a href="http://www.busybox.org/">http://www.busybox.org/</a>).
Note that you can run everything as a normal user. There is no need to be root to
configure and use the Buildroot. The first step is to run the configuration
assistant:</p>
<pre>
@ -156,11 +119,23 @@
</pre>
<p>This command will download, configure and compile all the selected
tools, and finally generate a target filesystem. The target filesystem will
be named <code>root_fs_ARCH.EXT</code> where <code>ARCH</code> is your
architecture and <code>EXT</code> depends on the type of target filesystem
selected in the <code>Target options</code> section of the configuration
tool.</p>
tools, and finally generate target firmware images and additional packages
(depending on your selections in <code>make menuconfig</code>.
All the target files can be found in the <code>bin/</code> subdirectory.
You can compile firmware images containing two different filesystem types:
<ul>
<li>jffs2</li>
<li>squashfs</li>
</ul>
<p><code>jffs2</code> contains a writable root filesystem, which will expand to
the size of your flash image. Note that you if you use the generic firmware
Image, you need to pick the right image for your Flash size, because of different
eraseblock sizes.</p>
<p><code>squashfs</code> contains a read-only root filesystem using a modified
<code>squashfs</code> filesystem with LZMA compression. When booting it, you can
create a writable second filesystem, which will contain your modifications to
the root filesystem, including the packages you install.
<h2><a name="custom_targetfs" id="custom_targetfs"></a>Customizing the
target filesystem</h2>
@ -170,55 +145,27 @@
<ul>
<li>Customize the target filesystem directly, and rebuild the image. The
target filesystem is available under <code>build_ARCH/root/</code> where
<code>ARCH</code> is the chosen target architecture. You can simply make
your changes here, and run make afterwards, which will rebuild the target
filesystem image. This method allows to do everything on the target
filesystem, but if you decide to completely rebuild your toolchain and
tools, these changes will be lost.</li>
<code>ARCH</code> is the chosen target architecture, usually mipsel.
You can simply make your changes here, and run make target_install afterwards,
which will rebuild the target filesystem image. This method allows to do
everything on the target filesystem, but if you decide to rebuild your toolchain,
tools or packages, these changes will be lost.</li>
<li>Customize the target filesystem skeleton, available under
<code>target/default/target_skeleton/</code>. You can customize
configuration files or other stuff here. However, the full file hierarchy
is not yet present, because it's created during the compilation process.
So you can't do everything on this target filesystem skeleton, but
changes to it remains even you completely rebuild the cross-compilation
changes to it remains even when you completely rebuild the cross-compilation
toolchain and the tools.<br />
You can also customize the <code>target/default/device_table.txt</code>
file which is used by the tools that generate the target filesystem image
to properly set permissions and create device nodes. The
<code>target/default/skel.tar.gz</code> file contains the main
directories of a root filesystem and there is no obvious reason for which
it should be changed. These main directories are in an tarball inside of
inside the skeleton because it contains symlinks that would be broken
otherwise.</li>
</ul>
<h2><a name="custom_busybox" id="custom_busybox"></a>Customizing the
Busybox configuration</h2>
<p>Busybox is very configurable, and you may want to customize it. You can
follow these simple steps to do it. It's not an optimal way, but it's
simple and it works.</p>
<ol>
<li>Make a first compilation of buildroot with busybox without trying to
customize it.</li>
<li>Go into <code>build_ARCH/busybox/</code> and run <code>make
menuconfig</code>. The nice configuration tool appears and you can
customize everything.</li>
<li>Copy the <code>.config</code> file to
<code>package/busybox/busybox.config</code> so that your customized
configuration will remains even if you remove the cross-compilation
toolchain.</li>
<li>Run the compilation of buildroot again.</li>
</ol>
<p>Otherwise, you can simply change the
<code>package/busybox/busybox.config</code> file if you know the options
you want to change without using the configuration tool.</p>
<p>Busybox is very configurable, and you may want to customize it.
Its configuration is completely integrated into the main menuconfig system.
You can find it under "OpenWrt Package Selection" =&gt; "Busybox Configuration"</p>
<h2><a name="custom_uclibc" id="custom_uclibc"></a>Customizing the uClibc
configuration</h2>
@ -239,17 +186,17 @@
<li>Go into the directory
<code>toolchain_build_ARCH/uClibc/</code> and run <code>make
menuconfig</code>. The nice configuration assistant, similar to
the one used in the Linux Kernel or in Buildroot appears. Make
the one used in the Linux Kernel appears. Make
your configuration as appropriate.</li>
<li>Copy the <code>.config</code> file to
<code>toolchain/uClibc/uClibc.config</code> or
<code>toolchain/uClibc/uClibc.config-locale</code>. The former
is used if you haven't selected locale support in Buildroot
is used if you haven't selected locale support in the Buildroot
configuration, and the latter is used if you have selected
locale support.</li>
<li>Run the compilation of Buildroot again</li>
<li>Run the compilation again</li>
</ol>
@ -258,18 +205,17 @@
<code>toolchain/uClibc/uClibc.config-locale</code> without running
the configuration assistant.</p>
<h2><a name="buildroot_innards" id="buildroot_innards"></a>How Buildroot
<h2><a name="buildroot_innards" id="buildroot_innards"></a>How OpenWrt Buildroot
works</h2>
<p>As said above, Buildroot is basically a set of Makefiles that download,
<p>As said above, OpenWrt is basically a set of Makefiles that download,
configure and compiles software with the correct options. It also includes
some patches for various software, mainly the ones involved in the
cross-compilation tool chain (<code>gcc</code>, <code>binutils</code> and
uClibc).</p>
<p>There is basically one Makefile per software, and they are named with
the <code>.mk</code> extension. Makefiles are split into three
sections:</p>
<p>There is basically one Makefile per software, and they are named <code>Makefile</code>.
Makefiles are split into three sections:</p>
<ul>
<li><b>package</b> (in the <code>package/</code> directory) contains the
@ -286,26 +232,18 @@
<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's a
sub-directory with the required files. There is also a
<code>default/</code> directory that contains the target filesystem
skeleton.</li>
: jffs2 and squashfs.
</ul>
<p>Each directory contains at least 3 files :</p>
<ul>
<li><code>something.mk</code> is the Makefile that downloads, configures,
<li><code>Makefile</code> is the Makefile that downloads, configures,
compiles and installs the software <code>something</code>.</li>
<li><code>Config.in</code> is a part of the configuration tool
description file. It describes the option related to the current
software.</li>
<li><code>Makefile.in</code> is a part of Makefile that sets various
variables according to the configuration given through the configuration
tool. For most tools it simply involves adding the name of the tool to
the <code>TARGETS</code> variable.</li>
</ul>
<p>The main Makefile do the job through the following steps (once the
@ -338,24 +276,22 @@
<li>Create the target directory (<code>build_ARCH/root/</code> by
default) and the target filesystem skeleton. This directory will contain
the final root filesystem. To setup it up, it first deletes it, then it
uncompress the <code>target/default/skel.tar.gz</code> file to create the
main subdirectories and symlinks, copies the skeleton available in
<code>target/default/target_skeleton</code> and then removes useless
<code>CVS/</code> directories.</li>
copies the skeleton available in <code>target/default/target_skeleton</code>
and then removes useless <code>CVS/</code> directories.</li>
<li>Make the <code>TARGETS</code> dependency. This is where all the job
is done : all <code>Makefile.in</code> files "subscribe" targets into
this global variable, so that the needed tools gets compiled.</li>
<li>Call the <code>prepare</code>, <code>compile</code> and <code>install</code>
targets for the subdirectories <code>toolchain</code>, <code>package</code>
and <code>target</code></li>
</ol>
<h2><a name="using_toolchain" id="using_toolchain"></a>Using the
uClibc toolchain</h2>
<p>You may want to compile 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>
that are not packaged in OpenWrt. In order to do this, you can
use the toolchain that was generated by the Buildroot.</p>
<p>The toolchain generated by Buildroot by default is located in
<p>The toolchain generated by the Buildroot by default is located in
<code>build_ARCH/staging_dir/</code>. The simplest way to use it
is to add <code>build_ARCH/staging_dir/bin/</code> to your PATH
environnement variable, and then to use
@ -396,7 +332,7 @@ mips-linux-gcc -o foo foo.c
<p>If you want to use the generated toolchain for other purposes,
you can configure Buildroot to generate it elsewhere using the
option of the configuration tool : <code>Build options ->
option of the configuration tool : <code>Build options -&gt;
Toolchain and header file location</code>, which defaults to
<code>$(BUILD_DIR)/staging_dir/</code>.</p>
@ -412,7 +348,7 @@ mips-linux-gcc -o foo foo.c
toolchain and the target filesystem with exactly the same
versions.</p>
<h2><a name="add_software" id="add_software"></a>Extending Buildroot with
<h2><a name="add_software" id="add_software"></a>Extending OpenWrt with
more software</h2>
<p>This section will only consider the case in which you want to
@ -432,7 +368,7 @@ mips-linux-gcc -o foo foo.c
<pre>
config BR2_PACKAGE_FOO
bool "foo"
tristate "foo"
default n
help
This is a comment that explains what foo is.
@ -441,56 +377,77 @@ config BR2_PACKAGE_FOO
<p>Of course, you can add other options to configure particular
things in your software.</p>
<h3><code>Makefile.in</code> file</h3>
<h3><code>Makefile</code> in the package directory</h3>
<p>Then, write a <code>Makefile.in</code> file. Basically, this is
a very short <i>Makefile</i> that adds the name of the software to
the list of <code>TARGETS</code> that Buildroot will generate. In
fact, the name of the software is the the identifier of the target
inside the real <i>Makefile</i> that will do everything (download,
compile, install), and that we study below. Back to
<code>Makefile.in</code>, here is an example :</p>
<p>To add your package to the build process, you need to edit
the Makefile in the <code>package/</code> directory. Locate the
lines that look like the following:</p>
<pre>
ifeq ($(strip $(BR2_PACKAGE_FOO)),y)
TARGETS+=foo
endif
package-$(BR2_PACKAGE_FOO) += foo
</pre>
<p>As you can see, this short <i>Makefile</i> simply adds the
target <code>foo</code> to the list of targets handled by Buildroot
if software <i>foo</i> was selected using the configuration tool.</p>
<p>As you can see, this short line simply adds the target
<code>foo</code> to the list of targets handled by OpenWrt Buildroot.</p>
<p>In addition to the default dependencies, you make your package
depend on another package (e.g. a library) by adding a line:
<pre>
foo-compile: bar-compile
</pre>
<h3>The <i>.control</i> file</h3>
<p>Additionally, you need to create a control file which contains
information about your package, readable by the <i>ipkg</i> package
utility.</p>
<p>The file looks like this</p>
<pre>
1 Package: foo
2 Priority: optional
3 Section: net
4 Maintainer: Foo Software &lt;foo@foosoftware.com&gt;
5 Source: http://foosoftware.com
6 Description: Your Package Description
</pre>
<p>You can skip the usual <code>Version:</code> and <code>Architecture</code>
fields, as they will be generated by the <code>make-ipkg-dir.sh</code> script
called from your Makefile</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
<code>Makefile</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:=less-$(FOO_VERSION).tar.gz
8 FOO_SITE:=http://www.foosoftware.org/downloads
9 FOO_DIR:=$(BUILD_DIR)/less-$(FOO_VERSION)
10 FOO_BINARY:=foo
11 FOO_TARGET_BINARY:=usr/bin/foo
2 # foo
3 #############################################################
4 PKG_NAME:=foo
5 PKG_VERSION:=1.0
6 PKG_RELEASE:=1
7 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
8 PKG_SITE:=http://www.foosoftware.org/downloads
9 PKG_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
10 PKG_IPK:=$(PACKAGE_DIR)/$(PKG_NAME)_$(PKG_VERSION)-$(PKG_RELEASE)_$(ARCH).ipk
11 PKG_IPK_DIR:=$(PKG_DIR)/ipkg
12
13 $(DL_DIR)/$(FOO_SOURCE):
14 $(WGET) -P $(DL_DIR) $(FOO_SITE)/$(FOO_SOURCE)
13 $(DL_DIR)/$(PKG_SOURCE):
14 $(WGET) -P $(DL_DIR) $(PKG_SITE)/$(PKG_SOURCE)
15
16 $(FOO_DIR)/.source: $(DL_DIR)/$(FOO_SOURCE)
17 zcat $(DL_DIR)/$(FOO_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) -
18 touch $(FOO_DIR)/.source
16 $(PKG_DIR)/.source: $(DL_DIR)/$(PKG_SOURCE)
17 zcat $(DL_DIR)/$(PKG_SOURCE) | tar -C $(BUILD_DIR) $(TAR_OPTIONS) -
18 touch $(PKG_DIR)/.source
19
20 $(FOO_DIR)/.configured: $(FOO_DIR)/.source
21 (cd $(FOO_DIR); \
20 $(PKG_DIR)/.configured: $(PKG_DIR)/.source
21 (cd $(PKG_DIR); \
22 $(TARGET_CONFIGURE_OPTS) \
23 CFLAGS="$(TARGET_CFLAGS)" \
24 ./configure \
@ -500,60 +457,60 @@ endif
28 --prefix=/usr \
29 --sysconfdir=/etc \
30 );
31 touch $(FOO_DIR)/.configured;
31 touch $(PKG_DIR)/.configured;
32
33 $(FOO_DIR)/$(FOO_BINARY): $(FOO_DIR)/.configured
34 $(MAKE) CC=$(TARGET_CC) -C $(FOO_DIR)
33 $(PKG_DIR)/foo $(PKG_DIR)/.configured
34 $(MAKE) CC=$(TARGET_CC) -C $(PKG_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)
36 $(PKG_IPK): $(PKG_DIR)/$(PKG_BINARY)
37 $(SCRIPT_DIR)/make-ipkg-dir.sh $(PKG_IPK_DIR) $(PKG_NAME).control $(PKG_VERSION)-$(PKG_RELEASE) $(ARCH)
38 $(MAKE) prefix=$(PKG_IPK_DIR)/usr -C $(PKG_DIR) install
39 rm -Rf $(PKG_IPK_DIR)/usr/man
40 $(IPKG_BUILD) $(PKG_IPK_DIR) $(PACKAGE_DIR)
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
42 $(IPKG_STATE_DIR)/info/$(PKG_NAME).list: $(PKG_IPK)
43 $(IPKG) install $(PKG_IPK)
44
45 prepare: $(PKG_DIR)/.source
46 compile: $(PKG_IPK)
47 install: $(IPKG_STATE_DIR)/info/$(PKG_NAME).list
48 clean:
49 rm -rf $(PKG_DIR)
50 rm -f $(PKG_IPK)
</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>
the other <code>Makefile</code> files in the <code>package</code>
directory.</p>
<p>At lines 6-11, a couple of useful variables are defined :</p>
<p>At lines 4-11, a couple of useful variables are defined :</p>
<ul>
<li><code>PKG_NAME</code> : The package name, e.g. <i>foo</i>.</li>
<li><code>FOO_VERSION</code> : The version of <i>foo</i> that
<li><code>PKG_VERSION</code> : The version of the package 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>PKG_RELEASE</code> : The release number that will be
appended to the version number of your <i>ipkg</i> package.
<li><code>FOO_SITE</code> : The HTTP or FTP site from which
<i>foo</i> archive is downloaded. It must include the complete
<li><code>PKG_SOURCE</code> : The name of the tarball of
your package on the download website of FTP site. As you can see
<code>PKG_NAME</code> and <code>PKG_VERSION</code> are used.</li>
<li><code>PKG_SITE</code> : The HTTP or FTP site from which
the 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
<li><code>PKG_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>
<li><code>PKG_IPK</code> : The resulting <i>ipkg</i> pacakge
</ul>
@ -590,34 +547,33 @@ endif
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
<p>Lines 36-40 defines a target and associated rules that create
the <i>ipkg</i> package which can optionally be embedded into
the resulting firmware image. It depends on the binary file in
the source directory, to make sure the software has been compiled.
It uses the make-ipkg-dir.sh script, which will create the ipkg
build directory for your package, copy your control file into
that directory and add version and architecture information.
Then it calls 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>
removed to save space.
Finally <code>IPKG_BUILD</code> is called to create the package.</p>
<p>Line 40 defines the main target of the software, the one
referenced in the <code>Makefile.in</code> file. This targets
should first of all depends on the dependecies of the software (in
our example, <i>uclibc</i> and <i>ncurses</i>), and then to the
final binary. This last dependency will call all previous
dependencies in the right order. </p>
<p>Line 42 and 43 define the installation target of your package,
which will embed the software into the target filesystem.</p>
<p>Line 42 defines a simple target that only downloads the code
source. This is not used during normal operation of Buildroot, but
might be useful.</p>
<p>Lignes 44-46 define a simple target to clean the software build
by calling the <i>Makefiles</i> with the appropriate option.</p>
<p>Lines 48-49 define a simple target to completely remove the
directory in which the software was uncompressed, configured and
compiled.</p>
<p>Lines 45-50 define the main targets that the Makefile in the
<code>package</code> dir calls.
<ul>
<li><code>prepare</code> : Download and unpack the source</li>
<li><code>compile</code> : Compile the source and create the package</li>
<li><code>install</code> : Embed the package into the target filesystem</li>
<li><code>clean</code> : Remove all the files created by the build process</li>
</ul></p>
<h3>Conclusion</h3>
@ -627,17 +583,12 @@ endif
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>
don't forget to send a patch to OpenWrt developers !</p>
<h2><a name="links" id="links"></a>Ressources</h2>
<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>
<p>To learn more about OpenWrt Buildroot you can visit this
website: <a href="http://openwrt.org/">http://openwrt.org/</a></p>
</div>
</body>