Buildroot

Usage and documentation by Thomas Petazzoni. Contributions from - Karsten Kruse, Ned Ludd, Martin Herren.

Buildroot usage and documentation by Thomas Petazzoni. Contributions from + Karsten Kruse, Ned Ludd, Martin Herren and others.

$LastChangedDate$

About Buildroot
Obtaining Buildroot
Using Buildroot

About Buildroot

Buildroot is a set of Makefiles and patches that allows to easily +

Buildroot is a set of Makefiles and patches that allow to easily generate both a cross-compilation toolchain and a root filesystem for your target. The cross-compilation toolchain uses uClibc (http://www.uclibc.org/), a tiny C standard @@ -65,9 +66,9 @@ toolchain runs on an x86 processor and generates code for a x86 processor. Under most Linux systems, the compilation toolchain uses the GNU libc as C standard library. This compilation - toolchain is called the "host compilation toolchain", and more + 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 + working is called the "host system". The compilation toolchain is provided by your distribution, and Buildroot has nothing to do with it.

To download Buildroot using SVN, you can simply follow - the rules described on the "Accessing SVN"-page (http://buildroot.uclibc.org/subversion.html) of the uClibc buildroot website (http://buildroot.uclibc.org), and download the @@ -133,7 +134,7 @@ in the Linux Kernel (http://www.kernel.org/) or in Busybox (http://www.busybox.org/). Note that - you can run everything as a normal user. There is no need to be root to + you can build everything as a normal user. There is no need to be root to configure and use Buildroot. The first step is to run the configuration assistant:

Target options

If you intend to do an offline-build and just want to download all + sources that you previously selected in "make menuconfig" then + issue:

+ $ make source
+

You can now disconnect or copy the content of your dl + directory to the build-host.

+ Environment variables

Buildroot optionally honors some environment variables that are passed + to make :

HOSTCXX +
HOSTCC +
UCLIBC_CONFIG_FILE=<path/to/.config> +
BUSYBOX_CONFIG_FILE=<path/to/.config> +

An example that uses config files located in the toplevel directory and + in your $HOME:

+$ make UCLIBC_CONFIG_FILE=uClibc.config BUSYBOX_CONFIG_FILE=$HOME/bb.config
+

If you want to use a compiler other than the default gcc + or g++ for building helper-binaries on your host, then do

+$ make HOSTCXX=g++-4.3-HEAD HOSTCC=gcc-4.3-HEAD
+

Customizing the target filesystem

Customizing the Busybox configuration

Busybox is very configurable, and you may want to customize it. You can +

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.

Make a first compilation of buildroot with busybox without trying to customize it.
Go into build_ARCH/busybox/ and run make - menuconfig. The nice configuration tool appears and you can +
Invoke make busybox-menuconfig. + The nice configuration tool appears and you can customize everything.
Copy the .config file to - package/busybox/busybox.config so that your customized - configuration will remains even if you remove the cross-compilation - toolchain.
Run the compilation of buildroot again.

Otherwise, you can simply change the package/busybox/busybox.config file if you know the options you want to change without using the configuration tool.

If you want to use an existing config file for busybox, then see + section environment variables.

Customizing the uClibc configuration

Make a first compilation of buildroot without trying to customize uClibc.
Go into the directory - toolchain_build_ARCH/uClibc/ and run make - menuconfig. The nice configuration assistant, similar to +
Invoke make uclibc-menuconfig. + The nice configuration assistant, similar to the one used in the Linux Kernel or in Buildroot appears. Make your configuration as appropriate.

toolchain/uClibc/uClibc.config-locale

If you want to use an existing config file for uclibc, then see + section environment variables.

How Buildroot works

Add the TARGETS dependency. This should generally check if the configuration option for this package is enabled, and if so then - "subscribe" this package to be compiled by adding it to the TARGETS - global variable.

Using the @@ -367,7 +401,7 @@ ~/buildroot/) :

-export PATH=$PATH:~/buildroot/build_mips/staging_dir/bin/
+export PATH="$PATH:~/buildroot/build_mips/staging_dir/bin/"

Then you can simply do :

@@ -621,7 +655,7 @@ config BR2_PACKAGE_FOO

Lines 51-58 adds the target foo 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" + 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