# The Buildroot user manual

List of Examples

17.1. Config script: divine package
17.2. Config script: imagemagick package:

#

Buildroot 2014.11-rc1 manual generated on 2014-11-12 22:36:50 UTC from git revision 7412885

The Buildroot manual is written by the Buildroot developers. It is licensed under the GNU General Public License, version 2. Refer to the COPYING file in the Buildroot sources for the full text of this license.

Copyright © 2004-2014 The Buildroot developers

# Part I. Getting started

## Chapter 1. About Buildroot

Buildroot is a tool that simplifies and automates the process of building a complete Linux system for an embedded system, using cross-compilation.

In order to achieve this, Buildroot is able to generate a cross-compilation toolchain, a root filesystem, a Linux kernel image and a bootloader for your target. Buildroot can be used for any combination of these options, independently (you can for example use an existing cross-compilation toolchain, and build only your root filesystem with Buildroot).

Buildroot is useful mainly for people working with embedded systems. Embedded systems often use processors that are not the regular x86 processors everyone is used to having in his PC. They can be PowerPC processors, MIPS processors, ARM processors, etc.

Buildroot supports numerous processors and their variants; it also comes with default configurations for several boards available off-the-shelf. Besides this, a number of third-party projects are based on, or develop their BSP [1] or SDK [2] on top of Buildroot.

[1] BSP: Board Support Package

[2] SDK: Software Development Kit

## Chapter 2. System requirements

Buildroot is designed to run on Linux systems.

While Buildroot itself will build most host packages it needs for the compilation, certain standard Linux utilities are expected to be already installed on the host system. Below you will find an overview of the mandatory and optional packages (note that package names may vary between distributions).

## 2.1. Mandatory packages

- Build tools:

  - `which`
  - `sed`
  - `make` (version 3.81 or any later)
  - `binutils`
  - `build-essential` (only for Debian based systems)
  - `gcc` (version 2.95 or any later)
  - `g++` (version 2.95 or any later)
  - `bash`
  - `patch`
  - `gzip`
  - `bzip2`
  - `perl` (version 5.8.7 or any later)
  - `tar`
  - `cpio`
  - `python` (version 2.6 or 2.7)
  - `unzip`
  - `rsync`

- Source fetching tools:

  - `wget`

## 2.2. Optional packages

- Configuration interface dependencies:

  For these libraries, you need to install both runtime and development data, which in many distributions are packaged separately. The development packages typically have a -dev or -devel suffix.

  - `ncurses5` to use the menuconfig interface
  - `qt4` to use the xconfig interface
  - `glib2`, `gtk2` and `glade2` to use the gconfig interface

- Source fetching tools:

  In the official tree, most of the package sources are retrieved using `wget` from ftp, http or https locations. A few packages are only available through a version control system. Moreover, Buildroot is capable of downloading sources via other tools, like `rsync` or `scp` (refer to Chapter 19, Download infrastructure for more details). If you enable packages using any of these methods, you will need to install the corresponding tool on the host system:

  - `bazaar`
  - `cvs`
  - `git`
  - `mercurial`
  - `rsync`
  - `scp`
  - `subversion`

- Java-related packages, if the Java Classpath needs to be built for the target system:

  - The `javac` compiler
  - The `jar` tool

- Documentation generation tools:

  - `asciidoc`, version 8.6.3 or higher
  - `w3m`
  - `python` with the `argparse` module (automatically present in 2.7+ and 3.2+)
  - `dblatex` (required for the pdf manual only)

- Graph generation tools:

  - `graphviz` to use graph-depends and <pkg>-graph-depends
  - `python-matplotlib` to use graph-build

## Chapter 3. Getting Buildroot

Buildroot releases are made every 3 months, in February, May, August and November. Release numbers are in the format YYYY.MM, so for example 2013.02, 2014.08.

Release tarballs are available at http://buildroot.org/downloads/.

If you want to follow development, you can use the daily snapshots or make a clone of the Git repository. Refer to the Download page of the Buildroot website for more details.

## Chapter 4. Buildroot quick start

Important: you can and should build everything as a normal user. There is no need to be root to configure and use Buildroot. By running all commands as a regular user, you protect your system against packages behaving badly during compilation and installation.

The first step when using Buildroot is to create a configuration. Buildroot has a nice configuration tool similar to the one you can find in the Linux kernel or in BusyBox.

From the buildroot directory, run

     $ make menuconfig

for the original curses-based configurator, or

     $ make nconfig

for the new curses-based configurator, or

     $ make xconfig

for the Qt-based configurator, or

     $ make gconfig

for the GTK-based configurator.

All of these "make" commands will need to build a configuration utility (including the interface), so you may need to install "development" packages for relevant libraries used by the configuration utilities. Refer to Chapter 2, System requirements for more details, specifically the optional requirements Section 2.2, “Optional packages” to get the dependencies of your favorite interface.

For each menu entry in the configuration tool, you can find associated help that describes the purpose of the entry. Refer to Chapter 6, Buildroot configuration for details on some specific configuration aspects.

Once everything is configured, the configuration tool generates a `.config` file that contains the entire configuration. This file will be read by the top-level Makefile.

To start the build process, simply run:

     $ make

You should never use `make -jN` with Buildroot: top-level parallel make is currently not supported. Instead, use the `BR2_JLEVEL` option to tell Buildroot to run the compilation of each individual package with `make -jN`.

The `make` command will generally perform the following steps:

- download source files (as required);
- configure, build and install the cross-compilation toolchain, or simply import an external toolchain;
- configure, build and install selected target packages;
- build a kernel image, if selected;
- build a bootloader image, if selected;
- create a root filesystem in selected formats.

Buildroot output is stored in a single directory, `output/`. This directory contains several subdirectories:

- `images/` where all the images (kernel image, bootloader and root filesystem images) are stored. These are the files you need to put on your target system.
- `build/` where all the components are built (this includes tools needed by Buildroot on the host and packages compiled for the target). This directory contains one subdirectory for each of these components.
- `staging/` which contains a hierarchy similar to a root filesystem hierarchy. This directory contains the headers and libraries of the cross-compilation toolchain and all the userspace packages selected for the target. However, this directory is not intended to be the root filesystem for the target: it contains a lot of development files, unstripped binaries and libraries that make it far too big for an embedded system. These development files are used to compile libraries and applications for the target that depend on other libraries.
- `target/` which contains almost the complete root filesystem for the target: everything needed is present except the device files in `/dev/` (Buildroot can’t create them because Buildroot doesn’t run as root and doesn’t want to run as root). Also, it doesn’t have the correct permissions (e.g. setuid for the busybox binary). Therefore, this directory should not be used on your target. Instead, you should use one of the images built in the `images/` directory. If you need an extracted image of the root filesystem for booting over NFS, then use the tarball image generated in `images/` and extract it as root. Compared to `staging/`, `target/` contains only the files and libraries needed to run the selected target applications: the development files (headers, etc.) are not present, the binaries are stripped.
- `host/` contains the installation of tools compiled for the host that are needed for the proper execution of Buildroot, including the cross-compilation toolchain.

These commands, `make menuconfig|nconfig|gconfig|xconfig` and `make`, are the basic ones that allow to easily and quickly generate images fitting your needs, with all the features and applications you enabled.

More details about the "make" command usage are given in Section 8.1, “make tips”.

## Chapter 5. Community resources

Like any open source project, Buildroot has different ways to share information in its community and outside.

Each of those ways may interest you if you are looking for some help, want to understand Buildroot or contribute to the project.

Mailing List

  Buildroot has a mailing list for discussion and development. It is the main method of interaction for Buildroot users and developers.

  Only subscribers to the Buildroot mailing list are allowed to post to this list. You can subscribe via the mailing list info page.

  Mails that are sent to the mailing list are also available in the mailing list archives and via Gmane, at `gmane.comp.lib.uclibc.buildroot`. Please search the mailing list archives before asking questions, since there is a good chance someone else has asked the same question before.

IRC

  The Buildroot IRC channel #buildroot is hosted on Freenode. It is a useful place to ask quick questions or discuss on certain topics.

  When asking for help on IRC, share relevant logs or pieces of code using a code sharing website, such as http://code.bulix.org.

  Note that for certain questions, posting to the mailing list may be better as it will reach more people, both developers and users.

Bug tracker
  Bugs in Buildroot can be reported via the mailing list or alternatively via the Buildroot bugtracker. Please refer to Section 21.6, “Reporting issues/bugs or getting help” before creating a bug report.
Wiki
  The Buildroot wiki page is hosted on the eLinux wiki. It contains some useful links, an overview of past and upcoming events, and a TODO list.
Patchwork

  Patchwork is a web-based patch tracking system designed to facilitate the contribution and management of contributions to an open-source project. Patches that have been sent to a mailing list are 'caught' by the system, and appear on a web page. Any comments posted that reference the patch are appended to the patch page too. For more information on Patchwork see http://jk.ozlabs.org/projects/patchwork.

  Buildroot’s Patchwork website is mainly for use by Buildroot’s maintainer to ensure patches aren’t missed. It is also used by Buildroot patch reviewers (see also Section 21.3.1, “Applying Patches from Patchwork”). However, since the website exposes patches and their corresponding review comments in a clean and concise web interface, it can be useful for all Buildroot developers.

  The Buildroot patch management interface is available at http://patchwork.buildroot.org.

# Part II. User guide

## Chapter 6. Buildroot configuration

All the configuration options in `make *config` have a help text providing details about the option.

The `make *config` commands also offer a search tool. Read the help message in the different frontend menus to know how to use it:

- in menuconfig, the search tool is called by pressing `/`;
- in xconfig, the search tool is called by pressing `Ctrl` + `f`.

The result of the search shows the help message of the matching items. In menuconfig, numbers in the left column provide a shortcut to the corresponding entry. Just type this number to directly jump to the entry, or to the containing menu in case the entry is not selectable due to a missing dependency.

Although the menu structure and the help text of the entries should be sufficiently self-explanatory, a number of topics require additional explanation that cannot easily be covered in the help text and are therefore covered in the following sections.

## 6.1. Cross-compilation toolchain

A compilation toolchain is the set of tools that allows you to compile code for your system. It consists of a compiler (in our case, `gcc`), binary utils like assembler and linker (in our case, `binutils`) and a C standard library (for example GNU Libc, uClibc).

The system installed on your development station certainly already has a compilation toolchain that you can use to compile an application that runs on your system. If you’re using a PC, your compilation toolchain runs on an x86 processor and generates code for an x86 processor. Under most Linux systems, the compilation toolchain uses the GNU libc (glibc) as the C standard library. This compilation toolchain is called the "host compilation toolchain". The machine on which it is running, and on which you’re working, is called the "host system" [3].

The compilation toolchain is provided by your distribution, and Buildroot has nothing to do with it (other than using it to build a cross-compilation toolchain and other tools that are run on the development host).

As said above, the compilation toolchain that comes with your system runs on and generates code for the processor in your host system. As your embedded system has a different processor, you need a cross-compilation toolchain - a compilation toolchain that runs on your host system but generates code for your target system (and target processor). For example, if your host system uses x86 and your target system uses ARM, the regular compilation toolchain on your host runs on x86 and generates code for x86, while the cross-compilation toolchain runs on x86 and generates code for ARM.

Buildroot provides two solutions for the cross-compilation toolchain:

- The internal toolchain backend, called `Buildroot toolchain` in the configuration interface.
- The external toolchain backend, called `External toolchain` in the configuration interface.

The choice between these two solutions is done using the `Toolchain Type` option in the `Toolchain` menu. Once one solution has been chosen, a number of configuration options appear, they are detailed in the following sections.

### 6.1.1. Internal toolchain backend

The internal toolchain backend is the backend where Buildroot builds by itself a cross-compilation toolchain, before building the userspace applications and libraries for your target embedded system.

This backend supports several C libraries: uClibc, the glibc and eglibc.

Once you have selected this backend, a number of options appear. The most important ones allow to:

- Change the version of the Linux kernel headers used to build the toolchain. This item deserves a few explanations. In the process of building a cross-compilation toolchain, the C library is being built. This library provides the interface between userspace applications and the Linux kernel. In order to know how to "talk" to the Linux kernel, the C library needs to have access to the Linux kernel headers (i.e. the `.h` files from the kernel), which define the interface between userspace and the kernel (system calls, data structures, etc.). Since this interface is backward compatible, the version of the Linux kernel headers used to build your toolchain do not need to match exactly the version of the Linux kernel you intend to run on your embedded system. They only need to have a version equal or older to the version of the Linux kernel you intend to run. If you use kernel headers that are more recent than the Linux kernel you run on your embedded system, then the C library might be using interfaces that are not provided by your Linux kernel.
- Change the version of the GCC compiler, binutils and the C library.
- Select a number of toolchain options (uClibc only): whether the toolchain should have largefile support (i.e. support for files larger than 2 GB on 32 bits systems), IPv6 support, RPC support (used mainly for NFS), wide-char support, locale support (for internationalization), C++ support or thread support. Depending on which options you choose, the number of userspace applications and libraries visible in Buildroot menus will change: many applications and libraries require certain toolchain options to be enabled. Most packages show a comment when a certain toolchain option is required to be able to enable those packages. If needed, you can further refine the uClibc configuration by running `make uclibc-menuconfig`. Note however that all packages in Buildroot are tested against the default uClibc configuration bundled in Buildroot: if you deviate from this configuration by removing features from uClibc, some packages may no longer build.

It is worth noting that whenever one of those options is modified, then the entire toolchain and system must be rebuilt. See Section 8.2, “Understanding when a full rebuild is necessary”.

Advantages of this backend:

- Well integrated with Buildroot
- Fast, only builds what’s necessary

Drawbacks of this backend:

- Rebuilding the toolchain is needed when doing `make clean`, which takes time. If you’re trying to reduce your build time, consider using the External toolchain backend.

### 6.1.2. External toolchain backend

The external toolchain backend allows to use existing pre-built cross-compilation toolchains. Buildroot knows about a number of well-known cross-compilation toolchains (from Linaro for ARM, Sourcery CodeBench for ARM, x86, x86-64, PowerPC, MIPS and SuperH, Blackfin toolchains from Analog Devices, etc.) and is capable of downloading them automatically, or it can be pointed to a custom toolchain, either available for download or installed locally.

Then, you have three solutions to use an external toolchain:

- Use a predefined external toolchain profile, and let Buildroot download, extract and install the toolchain. Buildroot already knows about a few CodeSourcery, Linaro, Blackfin and Xilinx toolchains. Just select the toolchain profile in `Toolchain` from the available ones. This is definitely the easiest solution.
- 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 `Toolchain` through the available ones, unselect `Download toolchain automatically`, and fill the `Toolchain path` text entry with the path to your cross-compiling toolchain.
- Use a completely custom external toolchain. This is particularly useful for toolchains generated using crosstool-NG or with Buildroot itself. To do this, select the `Custom toolchain` solution in the `Toolchain` list. You need to fill the `Toolchain path`, `Toolchain prefix` and `External toolchain C library` options. Then, you have to tell Buildroot what your external toolchain supports. If your external toolchain uses the glibc library, you only have to tell whether your toolchain supports C++ or not and whether it has built-in RPC support. If your external toolchain uses the uClibc 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.

Our external toolchain support has been tested with toolchains from CodeSourcery and Linaro, toolchains generated by crosstool-NG, and toolchains generated by Buildroot itself. In general, all toolchains that support the sysroot feature should work. If not, do not hesitate to contact the developers.

We do not support toolchains or SDK generated by OpenEmbedded or Yocto, because these toolchains are not pure toolchains (i.e. just the compiler, binutils, the C and C++ libraries). Instead these toolchains come with a very large set of pre-compiled libraries and programs. Therefore, Buildroot cannot import the sysroot of the toolchain, as it would contain hundreds of megabytes of pre-compiled libraries that are normally built by Buildroot.

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.

If you want to generate a custom toolchain for your project, that can be used as an external toolchain in Buildroot, our recommendation is definitely to build it with crosstool-NG. We recommend to build the toolchain separately from Buildroot, and then import it in Buildroot using the external toolchain backend.

Advantages of this backend:

- Allows to use well-known and well-tested cross-compilation toolchains.
- Avoids the build time of the cross-compilation toolchain, which is often very significant in the overall build time of an embedded Linux system.
- Not limited to uClibc: glibc and eglibc toolchains are supported.

Drawbacks of this backend:

- If your pre-built external toolchain has a bug, may be hard to get a fix from the toolchain vendor, unless you build your external toolchain by yourself using Crosstool-NG.

#### External toolchain wrapper

When using an external toolchain, Buildroot generates a wrapper program, that transparently passes the appropriate options (according to the configuration) to the external toolchain programs. In case you need to debug this wrapper to check exactly what arguments are passed, you can set the environment variable `BR2_DEBUG_WRAPPER` to either one of:

- `0`, empty or not set: no debug
- `1`: trace all arguments on a single line
- `2`: trace one argument per line

## 6.2. /dev management

On a Linux system, the `/dev` directory contains special files, called device files, that allow userspace applications to access the hardware devices managed by the Linux kernel. Without these device files, your userspace applications would not be able to use the hardware devices, even if they are properly recognized by the Linux kernel.

Under `System configuration`, `/dev management`, Buildroot offers four different solutions to handle the `/dev` directory :

- The first solution is Static using device table. This is the old classical way of handling device files in Linux. With this method, the device files are persistently stored in the root filesystem (i.e. they persist across reboots), and there is nothing that will automatically create and remove those device files when hardware devices are added or removed from the system. Buildroot therefore creates a standard set of device files using a device table, the default one being stored in `system/device_table_dev.txt` in the Buildroot source code. This file is processed when Buildroot generates the final root filesystem image, and the device files are therefore not visible in the `output/target` directory. The `BR2_ROOTFS_STATIC_DEVICE_TABLE` option allows to change the default device table used by Buildroot, or to add an additional device table, so that additional device files are created by Buildroot during the build. So, if you use this method, and a device file is missing in your system, you can for example create a `board/<yourcompany>/<yourproject>/device_table_dev.txt` file that contains the description of your additional device files, and then you can set `BR2_ROOTFS_STATIC_DEVICE_TABLE` to `system/device_table_dev.txt board/<yourcompany>/<yourproject>/device_table_dev.txt`. For more details about the format of the device table file, see Chapter 22, Makedev syntax documentation.
- The second solution is Dynamic using devtmpfs only. devtmpfs is a virtual filesystem inside the Linux kernel that has been introduced in kernel 2.6.32 (if you use an older kernel, it is not possible to use this option). When mounted in `/dev`, this virtual filesystem will automatically make device files appear and disappear as hardware devices are added and removed from the system. This filesystem is not persistent across reboots: it is filled dynamically by the kernel. Using devtmpfs requires the following kernel configuration options to be enabled: `CONFIG_DEVTMPFS` and `CONFIG_DEVTMPFS_MOUNT`. When Buildroot is in charge of building the Linux kernel for your embedded device, it makes sure that those two options are enabled. However, if you build your Linux kernel outside of Buildroot, then it is your responsibility to enable those two options (if you fail to do so, your Buildroot system will not boot).
- The third solution is Dynamic using mdev. This method also relies on the devtmpfs virtual filesystem detailed above (so the requirement to have `CONFIG_DEVTMPFS` and `CONFIG_DEVTMPFS_MOUNT` enabled in the kernel configuration still apply), but adds the `mdev` userspace utility on top of it. `mdev` is a program part of BusyBox that the kernel will call every time a device is added or removed. Thanks to the `/etc/mdev.conf` configuration file, `mdev` can be configured to for example, set specific permissions or ownership on a device file, call a script or application whenever a device appears or disappear, etc. Basically, it allows userspace to react on device addition and removal events. `mdev` can for example be used to automatically load kernel modules when devices appear on the system. `mdev` is also important if you have devices that require a firmware, as it will be responsible for pushing the firmware contents to the kernel. `mdev` is a lightweight implementation (with fewer features) of `udev`. For more details about `mdev` and the syntax of its configuration file, see http://git.busybox.net/busybox/tree/docs/mdev.txt.
- The fourth solution is Dynamic using eudev. This method also relies on the devtmpfs virtual filesystem detailed above, but adds the `eudev` userspace daemon on top of it. `eudev` is a daemon that runs in the background, and gets called by the kernel when a device gets added or removed from the system. It is a more heavyweight solution than `mdev`, but provides higher flexibility. `eudev` is a standalone version of `udev`, the original userspace daemon used in most desktop Linux distributions, which is now part of Systemd. For more details, see http://en.wikipedia.org/wiki/Udev.

The Buildroot developers recommendation is to start with the Dynamic using devtmpfs only solution, until you have the need for userspace to be notified when devices are added/removed, or if firmwares are needed, in which case Dynamic using mdev is usually a good solution.

Note that if `systemd` is chosen as init system, /dev management will be performed by the `udev` program provided by `systemd`.

## 6.3. init system

The init program is the first userspace program started by the kernel (it carries the PID number 1), and is responsible for starting the userspace services and programs (for example: web server, graphical applications, other network servers, etc.).

Buildroot allows to use three different types of init systems, which can be chosen from `System configuration`, `Init system`:

- The first solution is BusyBox. Amongst many programs, BusyBox has an implementation of a basic `init` program, which is sufficient for most embedded systems. Enabling the `BR2_INIT_BUSYBOX` will ensure BusyBox will build and install its `init` program. This is the default solution in Buildroot. The BusyBox `init` program will read the `/etc/inittab` file at boot to know what to do. The syntax of this file can be found in http://git.busybox.net/busybox/tree/examples/inittab (note that BusyBox `inittab` syntax is special: do not use a random `inittab` documentation from the Internet to learn about BusyBox `inittab`). The default `inittab` in Buildroot is stored in `system/skeleton/etc/inittab`. Apart from mounting a few important filesystems, the main job the default inittab does is to start the `/etc/init.d/rcS` shell script, and start a `getty` program (which provides a login prompt).
- The second solution is systemV. This solution uses the old traditional sysvinit program, packed in Buildroot in `package/sysvinit`. This was the solution used in most desktop Linux distributions, until they switched to more recent alternatives such as Upstart or Systemd. `sysvinit` also works with an `inittab` file (which has a slightly different syntax than the one from BusyBox). The default `inittab` installed with this init solution is located in `package/sysvinit/inittab`.
- The third solution is systemd. `systemd` is the new generation init system for Linux. It does far more than traditional init programs: aggressive parallelization capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, keeps track of processes using Linux control groups, supports snapshotting and restoring of the system state, etc. `systemd` will be useful on relatively complex embedded systems, for example the ones requiring D-Bus and services communicating between each other. It is worth noting that `systemd` brings a fairly big number of large dependencies: `dbus`, `udev` and more. For more details about `systemd`, see http://www.freedesktop.org/wiki/Software/systemd.

The solution recommended by Buildroot developers is to use the BusyBox init as it is sufficient for most embedded systems. systemd can be used for more complex situations.

[3] This terminology differs from what is used by GNU configure, where the host is the machine on which the application will run (which is usually the same as target)

## Chapter 7. Configuration of other components

Before attempting to modify any of the components below, make sure you have already configured Buildroot itself, and have enabled the corresponding package.

BusyBox

  If you already have a BusyBox configuration file, you can directly specify this file in the Buildroot configuration, using `BR2_PACKAGE_BUSYBOX_CONFIG`. Otherwise, Buildroot will start from a default BusyBox configuration file.

  To make subsequent changes to the configuration, use `make busybox-menuconfig` to open the BusyBox configuration editor.

  It is also possible to specify a BusyBox configuration file through an environment variable, although this is not recommended. Refer to Section 8.6, “Environment variables” for more details.

uClibc
  Configuration of uClibc is done in the same way as for BusyBox. The configuration variable to specify an existing configuration file is `BR2_UCLIBC_CONFIG`. The command to make subsequent changes is `make uclibc-menuconfig`.
Linux kernel

  If you already have a kernel configuration file, you can directly specify this file in the Buildroot configuration, using `BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG`.

  If you do not yet have a kernel configuration file, you can either start by specifying a defconfig in the Buildroot configuration, using `BR2_LINUX_KERNEL_USE_DEFCONFIG`, or start by creating an empty file and specifying it as custom configuration file, using `BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG`.

  To make subsequent changes to the configuration, use `make linux-menuconfig` to open the Linux configuration editor.

Barebox
  Configuration of Barebox is done in the same way as for the Linux kernel. The corresponding configuration variables are `BR2_TARGET_BAREBOX_USE_CUSTOM_CONFIG` and `BR2_TARGET_BAREBOX_USE_DEFCONFIG`. To open the configuration editor, use `make barebox-menuconfig`.

## Chapter 8. General Buildroot usage

## 8.1. make tips

This is a collection of tips that help you make the most of Buildroot.

Display all commands executed by make:

     $ make V=1 <target>

Display all available targets:

     $ make help

Not all targets are always available, some settings in the `.config` file may hide some targets:

- `busybox-menuconfig` only works when `busybox` is enabled;
- `linux-menuconfig` and `linux-savedefconfig` only work when `linux` is enabled;
- `uclibc-menuconfig` is only available when the uClibc C library is selected in the internal toolchain backend;
- `barebox-menuconfig` and `barebox-savedefconfig` only work when the `barebox` bootloader is enabled.

Cleaning: Explicit cleaning is required when any of the architecture or toolchain configuration options are changed.

To delete all build products (including build directories, host, staging and target trees, the images and the toolchain):

     $ make clean

Generating the manual: The present manual sources are located in the docs/manual directory. To generate the manual:

     $ make manual-clean
     $ make manual

The manual outputs will be generated in output/docs/manual.

Notes

- A few tools are required to build the documentation (see: Section 2.2, “Optional packages”).

Resetting Buildroot for a new target: To delete all build products as well as the configuration:

     $ make distclean

Notes. If `ccache` is enabled, running `make clean` or `distclean` does not empty the compiler cache used by Buildroot. To delete it, refer to Section 8.11.3, “Using `ccache` in Buildroot”.

## 8.2. Understanding when a full rebuild is necessary

Buildroot does not attempt to detect what parts of the system should be rebuilt when the system configuration is changed through `make menuconfig`, `make xconfig` or one of the other configuration tools. In some cases, Buildroot should rebuild the entire system, in some cases, only a specific subset of packages. But detecting this in a completely reliable manner is very difficult, and therefore the Buildroot developers have decided to simply not attempt to do this.

Instead, it is the responsibility of the user to know when a full rebuild is necessary. As a hint, here are a few rules of thumb that can help you understand how to work with Buildroot:

- When the target architecture configuration is changed, a complete rebuild is needed. Changing the architecture variant, the binary format or the floating point strategy for example has an impact on the entire system.
- When the toolchain configuration is changed, a complete rebuild generally is needed. Changing the toolchain configuration often involves changing the compiler version, the type of C library or its configuration, or some other fundamental configuration item, and these changes have an impact on the entire system.
- When an additional package is added to the configuration, a full rebuild is not necessarily needed. Buildroot will detect that this package has never been built, and will build it. However, if this package is a library that can optionally be used by packages that have already been built, Buildroot will not automatically rebuild those. Either you know which packages should be rebuilt, and you can rebuild them manually, or you should do a full rebuild. For example, let’s suppose you have built a system with the `ctorrent` package, but without `openssl`. Your system works, but you realize you would like to have SSL support in `ctorrent`, so you enable the `openssl` package in Buildroot configuration and restart the build. Buildroot will detect that `openssl` should be built and will be build it, but it will not detect that `ctorrent` should be rebuilt to benefit from `openssl` to add OpenSSL support. You will either have to do a full rebuild, or rebuild `ctorrent` itself.
- When a package is removed from the configuration, Buildroot does not do anything special. It does not remove the files installed by this package from the target root filesystem or from the toolchain sysroot. A full rebuild is needed to get rid of this package. However, generally you don’t necessarily need this package to be removed right now: you can wait for the next lunch break to restart the build from scratch.
- When the sub-options of a package are changed, the package is not automatically rebuilt. After making such changes, rebuilding only this package is often sufficient, unless enabling the package sub-option adds some features to the package that are useful for another package which has already been built. Again, Buildroot does not track when a package should be rebuilt: once a package has been built, it is never rebuilt unless explicitly told to do so.
- When a change to the root filesystem skeleton is made, a full rebuild is needed. However, when changes to the root filesystem overlay, a post-build script or a post-image script are made, there is no need for a full rebuild: a simple `make` invocation will take the changes into account.

Generally speaking, when you’re facing a build error and you’re unsure of the potential consequences of the configuration changes you’ve made, do a full rebuild. If you get the same build error, then you are sure that the error is not related to partial rebuilds of packages, and if this error occurs with packages from the official Buildroot, do not hesitate to report the problem! As your experience with Buildroot progresses, you will progressively learn when a full rebuild is really necessary, and you will save more and more time.

For reference, a full rebuild is achieved by running:

    $ make clean all

## 8.3. Understanding how to rebuild packages

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.

Removing a package is unsupported by Buildroot without rebuilding from scratch. This is because Buildroot doesn’t keep track of which package installs what files in the `output/staging` and `output/target` directories, or which package would be compiled differently depending on the availability of another package.

The easiest way to rebuild a single package from scratch is to remove its build directory in `output/build`. Buildroot will then re-extract, re-configure, re-compile and re-install this package from scratch. You can ask buildroot to do this with the `make <package>-dirclean` command.

On the other hand, if you only want to restart the build process of a package from its compilation step, you can run `make <package>-rebuild`, followed by `make` or `make <package>`. It will restart the compilation and installation of the package, but not from scratch: it basically re-executes `make` and `make install` inside the package, so it will only rebuild files that changed.

If you want to restart the build process of a package from its configuration step, you can run `make <package>-reconfigure`, followed by `make` or `make <package>`. It will restart the configuration, compilation and installation of the package.

Internally, Buildroot creates so-called stamp files to keep track of which build steps have been completed for each package. They are stored in the package build directory, `output/build/<package>-<version>/` and are named `.stamp_<step-name>`. The commands detailed above simply manipulate these stamp files to force Buildroot to restart a specific set of steps of a package build process.

Further details about package special make targets are explained in Section 8.11.5, “Package-specific make targets”.

## 8.4. Offline builds

If you intend to do an offline build and just want to download all sources that you previously selected in the configurator (menuconfig, nconfig, xconfig or gconfig), then issue:

     $ make source

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

## 8.5. Building out-of-tree

As default, everything built by Buildroot is stored in the directory `output` in the Buildroot tree.

Buildroot also supports building out of tree with a syntax similar to the Linux kernel. To use it, add `O=<directory>` to the make command line:

     $ make O=/tmp/build

Or:

     $ cd /tmp/build; make O=$PWD -C path/to/buildroot

All the output files will be located under `/tmp/build`. If the `O` path does not exist, Buildroot will create it.

Note: the `O` path can be either an absolute or a relative path, but if it’s passed as a relative path, it is important to note that it is interpreted relative to the main Buildroot source directory, not the current working directory.

When using out-of-tree builds, the Buildroot `.config` and temporary files are also stored in the output directory. This means that you can safely run multiple builds in parallel using the same source tree as long as they use unique output directories.

For ease of use, Buildroot generates a Makefile wrapper in the output directory - so after the first run, you no longer need to pass `O=<…>` and `-C <…>`, simply run (in the output directory):

     $ make <target>

## 8.6. Environment variables

Buildroot also honors some environment variables, when they are passed to `make` or set in the environment:

- `HOSTCXX`, the host C++ compiler to use
- `HOSTCC`, the host C compiler to use
- `UCLIBC_CONFIG_FILE=<path/to/.config>`, path to the uClibc configuration file, used to compile uClibc, if an internal toolchain is being built. Note that the uClibc configuration file can also be set from the configuration interface, so through the Buildroot `.config` file; this is the recommended way of setting it.
- `BUSYBOX_CONFIG_FILE=<path/to/.config>`, path to the BusyBox configuration file. Note that the BusyBox configuration file can also be set from the configuration interface, so through the Buildroot `.config` file; this is the recommended way of setting it.
- `BR2_DL_DIR` to override the directory in which Buildroot stores/retrieves downloaded files Note that the Buildroot download directory can also be set from the configuration interface, so through the Buildroot `.config` file; this is the recommended way of setting it.
- `BR2_GRAPH_ALT`, if set and non-empty, to use an alternate color-scheme in build-time graphs
- `BR2_GRAPH_OUT` to set the filetype of generated graphs, either `pdf` (the default), or `png`.
- `BR2_GRAPH_DEPS_OPTS` to pass extra options to the dependency graph; see Section 8.8, “Graphing the dependencies between packages” for the accepted options
- `BR2_GRAPH_DOT_OPTS` is passed verbatim as options to the `dot` utility to draw the dependency graph.

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

## 8.7. Dealing efficiently with filesystem images

Filesystem images can get pretty big, depending on the filesystem you choose, the number of packages, whether you provisioned free space… Yet, some locations in the filesystems images may just be empty (e.g. a long run of zeroes); such a file is called a sparse file.

Most tools can handle sparse files efficiently, and will only store or write those parts of a sparse file that are not empty.

For example:

- `tar` accepts the `-S` option to tell it to only store non-zero blocks of sparse files:

  - `tar cf archive.tar -S [files…]` will efficiently store sparse files in a tarball
  - `tar xf archive.tar -S` will efficiently store sparse files extracted from a tarball

- `cp` accepts the `--sparse=WHEN` option (`WHEN` is one of `auto`, `never` or `always`):

  - `cp --sparse=always source.file dest.file` will make `dest.file` a sparse file if `source.file` has long runs of zeroes

Other tools may have similar options. Please consult their respective man pages.

You can use sparse files if you need to store the filesystem images (e.g. to transfer from one machine to another), or if you need to send them (e.g. to the Q&A team).

Note however that flashing a filesystem image to a device while using the sparse mode of `dd` may result in a broken filesystem (e.g. the block bitmap of an ext2 filesystem may be corrupted; or, if you have sparse files in your filesystem, those parts may not be all-zeroes when read back). You should only use sparse files when handling files on the build machine, not when transferring them to an actual device that will be used on the target.

## 8.8. Graphing the dependencies between packages

One of Buildroot’s jobs is to know the dependencies between packages, and make sure they are built in the right order. These dependencies can sometimes be quite complicated, and for a given system, it is often not easy to understand why such or such package was brought into the build by Buildroot.

In order to help understanding the dependencies, and therefore better understand what is the role of the different components in your embedded Linux system, Buildroot is capable of generating dependency graphs.

To generate a dependency graph of the full system you have compiled, simply run:

    make graph-depends

You will find the generated graph in `output/graphs/graph-depends.pdf`.

If your system is quite large, the dependency graph may be too complex and difficult to read. It is therefore possible to generate the dependency graph just for a given package:

    make <pkg>-graph-depends

You will find the generated graph in `output/graph/<pkg>-graph-depends.pdf`.

Note that the dependency graphs are generated using the `dot` tool from the Graphviz project, which you must have installed on your system to use this feature. In most distributions, it is available as the `graphviz` package.

By default, the dependency graphs are generated in the PDF format. However, by passing the `BR2_GRAPH_OUT` environment variable, you can switch to other output formats, such as PNG, PostScript or SVG. All formats supported by the `-T` option of the `dot` tool are supported.

    BR2_GRAPH_OUT=svg make graph-depends

The `graph-depends` behaviour can be controlled by setting options in the `BR2_GRAPH_DEPS_OPTS` environment variable. The accepted options are:

- `--depth N`, `-d N`, to limit the dependency depth to `N` levels. The default, `0`, means no limit.
- `--transitive`, `--no-transitive`, to draw (or not) the transitive dependencies. The default is to not draw transitive dependencies.
- `--colours R,T,H`, the comma-separated list of colours to draw the root package (`R`), the target packages (`T`) and the host packages (`H`). Defaults to: `lightblue,grey,gainsboro`

    BR2_GRAPH_DEPS_OPTS='-d 3 --no-transitive --colours=red,green,blue' make graph-depends

## 8.9. Graphing the build duration

When the build of a system takes a long time, it is sometimes useful to be able to understand which packages are the longest to build, to see if anything can be done to speed up the build. In order to help such build time analysis, Buildroot collects the build time of each step of each package, and allows to generate graphs from this data.

To generate the build time graph after a build, run:

    make graph-build

This will generate a set of files in `output/graphs` :

- `build.hist-build.pdf`, a histogram of the build time for each package, ordered in the build order.
- `build.hist-duration.pdf`, a histogram of the build time for each package, ordered by duration (longest first)
- `build.hist-name.pdf`, a histogram of the build time for each package, order by package name.
- `build.pie-packages.pdf`, a pie chart of the build time per package
- `build.pie-steps.pdf`, a pie chart of the global time spent in each step of the packages build process.

This `graph-build` target requires the Python Matplotlib and Numpy libraries to be installed (`python-matplotlib` and `python-numpy` on most distributions), and also the `argparse` module if you’re using a Python version older than 2.7 (`python-argparse` on most distributions).

By default, the output format for the graph is PDF, but a different format can be selected using the `BR2_GRAPH_OUT` environment variable. The only other format supported is PNG:

    BR2_GRAPH_OUT=png make graph-build

## 8.10. Integration with Eclipse

While a part of the embedded Linux developers like classical text editors like Vim or Emacs, and command-line based interfaces, a number of other embedded Linux developers like richer graphical interfaces to do their development work. Eclipse being one of the most popular Integrated Development Environment, Buildroot integrates with Eclipse in order to ease the development work of Eclipse users.

Our integration with Eclipse simplifies the compilation, remote execution and remote debugging of applications and libraries that are built on top of a Buildroot system. It does not integrate the Buildroot configuration and build processes themselves with Eclipse. Therefore, the typical usage model of our Eclipse integration would be:

- Configure your Buildroot system with `make menuconfig`, `make xconfig` or any other configuration interface provided with Buildroot.
- Build your Buildroot system by running `make`.
- Start Eclipse to develop, execute and debug your own custom applications and libraries, that will rely on the libraries built and installed by Buildroot.

The Buildroot Eclipse integration installation process and usage is described in detail at https://github.com/mbats/eclipse-buildroot-bundle/wiki.

## 8.11. Advanced usage

### 8.11.1. Using the generated toolchain outside Buildroot

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.

The toolchain generated by Buildroot is located by default in `output/host/`. The simplest way to use it is to add `output/host/usr/bin/` to your PATH environment variable and then to use `ARCH-linux-gcc`, `ARCH-linux-objdump`, `ARCH-linux-ld`, etc.

It is possible to relocate the toolchain - but then `--sysroot` must be passed every time the compiler is called to tell where the libraries and header files are.

It is also possible to generate the Buildroot toolchain in a directory other than `output/host` by using the `Build options → Host dir` option. This could be useful if the toolchain must be shared with other users.

### 8.11.2. Using `gdb` in Buildroot

Buildroot allows to do cross-debugging, where the debugger runs on the build machine and communicates with `gdbserver` on the target to control the execution of the program.

To achieve this:

- If you are using an internal toolchain (built by Buildroot), you must enable `BR2_PACKAGE_HOST_GDB`, `BR2_PACKAGE_GDB` and `BR2_PACKAGE_GDB_SERVER`. This ensures that both the cross gdb and gdbserver get built, and that gdbserver gets installed to your target.
- If you are using an external toolchain, you should enable `BR2_TOOLCHAIN_EXTERNAL_GDB_SERVER_COPY`, which will copy the gdbserver included with the external toolchain to the target. If your external toolchain does not have a cross gdb or gdbserver, it is also possible to let Buildroot build them, by enabling the same options as for the internal toolchain backend.

Now, to start debugging a program called `foo`, you should run on the target:

    gdbserver :2345 foo

This will cause `gdbserver` to listen on TCP port 2345 for a connection from the cross gdb.

Then, on the host, you should start the cross gdb using the following command line:

    <buildroot>/output/host/usr/bin/<tuple>-gdb -x <buildroot>/output/staging/usr/share/buildroot/gdbinit foo

Of course, `foo` must be available in the current directory, built with debugging symbols. Typically you start this command from the directory where `foo` is built (and not from `output/target/` as the binaries in that directory are stripped).

The `<buildroot>/output/staging/usr/share/buildroot/gdbinit` file will tell the cross gdb where to find the libraries of the target.

Finally, to connect to the target from the cross gdb:

    (gdb) target remote <target ip address>:2345

### 8.11.3. Using `ccache` in Buildroot

ccache 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.

`ccache` support is integrated in Buildroot. You just have to enable `Enable compiler cache` in `Build options`. This will automatically build `ccache` and use it for every host and target compilation.

The cache is located in `$HOME/.buildroot-ccache`. 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.

You can get statistics on the cache (its size, number of hits, misses, etc.) by running `make ccache-stats`.

The make target `ccache-options` and the `CCACHE_OPTIONS` variable provide more generic access to the ccache. For example

    # set cache limit size
    make CCACHE_OPTIONS="--max-size=5G" ccache-options

    # zero statistics counters
    make CCACHE_OPTIONS="--zero-stats" ccache-options

### 8.11.4. Location of downloaded packages

The various tarballs that are downloaded by Buildroot are all stored in `BR2_DL_DIR`, which by default is the `dl` directory. If you want to keep a complete version of Buildroot which is known to be working with the associated tarballs, you can make a copy of this directory. This will allow you to regenerate the toolchain and the target filesystem with exactly the same versions.

If you maintain several Buildroot trees, it might be better to have a shared download location. This can be achieved by pointing the `BR2_DL_DIR` environment variable to a directory. If this is set, then the value of `BR2_DL_DIR` in the Buildroot configuration is overridden. The following line should be added to `<~/.bashrc>`.

     $ export BR2_DL_DIR <shared download location>

The download location can also be set in the `.config` file, with the `BR2_DL_DIR` option. Unlike most options in the .config file, this value is overridden by the `BR2_DL_DIR` environment variable.

### 8.11.5. Package-specific make targets

Running `make <package>` builds and installs that particular package and its dependencies.

For packages relying on the Buildroot infrastructure, there are numerous special make targets that can be called independently like this:

    make <package>-<target>

The package build targets are (in the order they are executed):

command/target | Description
--- | ---
`source` | Fetch the source (download the tarball, clone the source repository, etc)
`depends` | Build and install all dependencies required to build the package
`extract` | Put the source in the package build directory (extract the tarball, copy the source, etc)
`patch` | Apply the patches, if any
`configure` | Run the configure commands, if any
`build` | Run the compilation commands
`install-staging` | target package: Run the installation of the package in the staging directory, if necessary
`install-target` | target package: Run the installation of the package in the target directory, if necessary
`install` | target package: Run the 2 previous installation commands host package: Run the installation of the package in the host directory

Additionally, there are some other useful make targets:

command/target | Description
--- | ---
`show-depends` | Displays the dependencies required to build the package
`graph-depends` | Generate a dependency graph of the package, in the context of the current Buildroot configuration. See this section Section 8.8, “Graphing the dependencies between packages” for more details about dependency graphs.
`dirclean` | Remove the whole package build directory
`rebuild` | Re-run the compilation commands - this only makes sense when using the `OVERRIDE_SRCDIR` feature or when you modified a file directly in the build directory
`reconfigure` | Re-run the configure commands, then rebuild - this only makes sense when using the `OVERRIDE_SRCDIR` feature or when you modified a file directly in the build directory

### 8.11.6. Using Buildroot during development

The normal operation of Buildroot is to download a tarball, extract it, configure, compile and install the software component found inside this tarball. The source code is extracted in `output/build/<package>-<version>`, which is a temporary directory: whenever `make clean` is used, this directory is entirely removed, and re-recreated at the next `make` invocation. Even when a Git or Subversion repository is used as the input for the package source code, Buildroot creates a tarball out of it, and then behaves as it normally does with tarballs.

This behavior is well-suited when Buildroot is used mainly as an integration tool, to build and integrate all the components of an embedded Linux system. However, if one uses Buildroot during the development of certain components of the system, this behavior is not very convenient: one would instead like to make a small change to the source code of one package, and be able to quickly rebuild the system with Buildroot.

Making changes directly in `output/build/<package>-<version>` is not an appropriate solution, because this directory is removed on `make clean`.

Therefore, Buildroot provides a specific mechanism for this use case: the `<pkg>_OVERRIDE_SRCDIR` mechanism. Buildroot reads an override file, which allows the user to tell Buildroot the location of the source for certain packages. By default this override file is named `local.mk` and located in the top directory of the Buildroot source tree, but a different location can be specified through the `BR2_PACKAGE_OVERRIDE_FILE` configuration option.

In this override file, Buildroot expects to find lines of the form:

    <pkg1>_OVERRIDE_SRCDIR = /path/to/pkg1/sources
    <pkg2>_OVERRIDE_SRCDIR = /path/to/pkg2/sources

For example:

    LINUX_OVERRIDE_SRCDIR = /home/bob/linux/
    BUSYBOX_OVERRIDE_SRCDIR = /home/bob/busybox/

When Buildroot finds that for a given package, an `<pkg>_OVERRIDE_SRCDIR` has been defined, it will no longer attempt to download, extract and patch the package. Instead, it will directly use the source code available in in the specified directory and `make clean` will not touch this directory. This allows to point Buildroot to your own directories, that can be managed by Git, Subversion, or any other version control system. To achieve this, Buildroot will use rsync to copy the source code of the component from the specified `<pkg>_OVERRIDE_SRCDIR` to `output/build/<package>-custom/`.

This mechanism is best used in conjunction with the `make <pkg>-rebuild` and `make <pkg>-reconfigure` targets. A `make <pkg>-rebuild all` sequence will rsync the source code from `<pkg>_OVERRIDE_SRCDIR` to `output/build/<package>-custom` (thanks to rsync, only the modified files are copied), and restart the build process of just this package.

In the example of the `linux` package above, the developer can then make a source code change in `/home/bob/linux` and then run:

    make linux-rebuild all

and in a matter of seconds gets the updated Linux kernel image in `output/images`. Similarly, a change can be made to the BusyBox source code in `/home/bob/busybox`, and after:

    make busybox-rebuild all

the root filesystem image in `output/images` contains the updated BusyBox.

## Chapter 9. Project-specific customization

Typical actions you may need to perform for a given project are:

- configuring Buildroot (including build options and toolchain, bootloader, kernel, package and filesystem image type selection)
- configuring other components, like the Linux kernel and BusyBox

- customizing the generated target filesystem

  - adding or overwriting files on the target filesystem (using `BR2_ROOTFS_OVERLAY`)
  - modifying or deleting files on the target filesystem (using `BR2_ROOTFS_POST_BUILD_SCRIPT`)
  - running arbitrary commands prior to generating the filesystem image (using `BR2_ROOTFS_POST_BUILD_SCRIPT`)
  - setting file permissions and ownership (using `BR2_ROOTFS_DEVICE_TABLE`)
  - adding custom devices nodes (using `BR2_ROOTFS_STATIC_DEVICE_TABLE`)
- adding custom user accounts (using `BR2_ROOTFS_USERS_TABLES`)
- running arbitrary commands after generating the filesystem image (using `BR2_ROOTFS_POST_IMAGE_SCRIPT`)
- adding project-specific patches to some packages (using `BR2_GLOBAL_PATCH_DIR`)
- adding project-specific packages

An important note regarding such project-specific customizations: please carefully consider which changes are indeed project-specific and which changes are also useful to developers outside your project. The Buildroot community highly recommends and encourages the upstreaming of improvements, packages and board support to the official Buildroot project. Of course, it is sometimes not possible or desirable to upstream because the changes are highly specific or proprietary.

This chapter describes how to make such project-specific customizations in Buildroot and how to store them in a way that you can build the same image in a reproducible way, even after running make clean. By following the recommended strategy, you can even use the same Buildroot tree to build multiple distinct projects!

## 9.1. Recommended directory structure

When customizing Buildroot for your project, you will be creating one or more project-specific files that need to be stored somewhere. While most of these files could be placed in any location as their path is to be specified in the Buildroot configuration, the Buildroot developers recommend a specific directory structure which is described in this section.

Orthogonal to this directory structure, you can choose where you place this structure itself: either inside the Buildroot tree, or outside of it using `BR2_EXTERNAL`. Both options are valid, the choice is up to you.

    +-- board/
    |   +-- <company>/
    |       +-- <boardname>/
    |           +-- linux.config
    |           +-- busybox.config
    |           +-- <other configuration files>
    |           +-- post_build.sh
    |           +-- post_image.sh
    |           +-- rootfs_overlay/
    |           |   +-- etc/
    |           |   +-- <some file>
    |           +-- patches/
    |               +-- foo/
    |               |   +-- <some patch>
    |               +-- libbar/
    |                   +-- <some other patches>
    |
    +-- configs/
    |   +-- <boardname>_defconfig
    |
    +-- package/
    |   +-- <company>/
    |       +-- Config.in (if not using BR2_EXTERNAL)
    |       +-- <company>.mk (if not using BR2_EXTERNAL)
    |       +-- package1/
    |       |    +-- Config.in
    |       |    +-- package1.mk
    |       +-- package2/
    |           +-- Config.in
    |           +-- package2.mk
    |
    +-- Config.in (if using BR2_EXTERNAL)
    +-- external.mk (if using BR2_EXTERNAL)

Details on the files shown above are given further in this chapter.

Note: if you choose to place this structure outside of the Buildroot tree using `BR2_EXTERNAL`, the <company> and possibly <boardname> components may be superfluous and can be left out.

### 9.1.1. Implementing layered customizations

It is quite common for a user to have several related projects that partly need the same customizations. Instead of duplicating these customizations for each project, it is recommended to use a layered customization approach, as explained in this section.

Almost all of the customization methods available in Buildroot, like post-build scripts and root filesystem overlays, accept a space-separated list of items. The specified items are always treated in order, from left to right. By creating more than one such item, one for the common customizations and another one for the really project-specific customizations, you can avoid unnecessary duplication. Each layer is typically embodied by a separate directory inside `board/<company>/`. Depending on your projects, you could even introduce more than two layers.

An example directory structure for where a user has two customization layers common and fooboard is:

    +-- board/
        +-- <company>/
            +-- common/
            |   +-- post_build.sh
            |   +-- rootfs_overlay/
            |   |   +-- ...
            |   +-- patches/
            |       +-- ...
            |
            +-- fooboard/
                +-- linux.config
                +-- busybox.config
                +-- <other configuration files>
                +-- post_build.sh
                +-- rootfs_overlay/
                |   +-- ...
                +-- patches/
                    +-- ...

For example, if the user has the `BR2_GLOBAL_PATCH_DIR` configuration option set as:

    BR2_GLOBAL_PATCH_DIR="board/<company>/common/patches board/<company>/fooboard/patches"

then first the patches from the common layer would be applied, followed by the patches from the fooboard layer.

## 9.2. Keeping customizations outside of Buildroot

As already briefly mentioned in Section 9.1, “Recommended directory structure”, you can place project-specific customizations in two locations:

- directly within the Buildroot tree, typically maintaining them using branches in a version control system so that upgrading to a newer Buildroot release is easy.
- outside of the Buildroot tree, using the `BR2_EXTERNAL` mechanism. This mechanism allows to keep package recipes, board support and configuration files outside of the Buildroot tree, while still having them nicely integrated in the build logic. This section explains how to use `BR2_EXTERNAL`.

`BR2_EXTERNAL` is an environment variable that can be used to point to a directory that contains Buildroot customizations. It can be passed to any Buildroot `make` invocation. It is automatically saved in the hidden `.br-external` file in the output directory. Thanks to this, there is no need to pass `BR2_EXTERNAL` at every `make` invocation. It can however be changed at any time by passing a new value, and can be removed by passing an empty value.

Note: the `BR2_EXTERNAL` path can be either an absolute or a relative path, but if it’s passed as a relative path, it is important to note that it is interpreted relative to the main Buildroot source directory, not to the Buildroot output directory.

Some examples:

     buildroot/ $ make BR2_EXTERNAL=/path/to/foobar menuconfig

From now on, external definitions from the `/path/to/foobar` directory will be used:

     buildroot/ $ make
     buildroot/ $ make legal-info

We can switch to another external definitions directory at any time:

     buildroot/ $ make BR2_EXTERNAL=/where/we/have/barfoo xconfig

Or disable the usage of external definitions:

     buildroot/ $ make BR2_EXTERNAL= xconfig

`BR2_EXTERNAL` allows three different things:

- One can store all the board-specific configuration files there, such as the kernel configuration, the root filesystem overlay, or any other configuration file for which Buildroot allows to set its location. The `BR2_EXTERNAL` value is available within the Buildroot configuration using `$(BR2_EXTERNAL)`. As an example, one could set the `BR2_ROOTFS_OVERLAY` Buildroot option to `$(BR2_EXTERNAL)/board/<boardname>/overlay/` (to specify a root filesystem overlay), or the `BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE` Buildroot option to `$(BR2_EXTERNAL)/board/<boardname>/kernel.config` (to specify the location of the kernel configuration file).

- One can store package recipes (i.e. `Config.in` and `<packagename>.mk`), or even custom configuration options and make logic. Buildroot automatically includes `$(BR2_EXTERNAL)/Config.in` to make it appear in the top-level configuration menu, and includes `$(BR2_EXTERNAL)/external.mk` with the rest of the makefile logic. Providing those two files is mandatory, but they can be empty.

  The main usage of this is to store package recipes. The recommended way to do this is to write a `$(BR2_EXTERNAL)/Config.in` file that looks like:

      source "$BR2_EXTERNAL/package/package1/Config.in"
      source "$BR2_EXTERNAL/package/package2/Config.in"

  Then, have a `$(BR2_EXTERNAL)/external.mk` file that looks like:

      include $(sort $(wildcard $(BR2_EXTERNAL)/package/*/*.mk))

  And then in `$(BR2_EXTERNAL)/package/package1` and `$(BR2_EXTERNAL)/package/package2` create normal Buildroot package recipes, as explained in Chapter 17, Adding new packages to Buildroot. If you prefer, you can also group the packages in subdirectories called <boardname> and adapt the above paths accordingly.

- One can store Buildroot defconfigs in the `configs` subdirectory of `$(BR2_EXTERNAL)`. Buildroot will automatically show them in the output of `make help` and allow them to be loaded with the normal `make <name>_defconfig` command. They will be visible under the `User-provided configs`' label in the make help output.

## 9.3. Storing the Buildroot configuration

The Buildroot configuration can be stored using the command `make savedefconfig`.

This strips the Buildroot configuration down by removing configuration options that are at their default value. The result is stored in a file called `defconfig`. If you want to save it in another place, change the `BR2_DEFCONFIG` option in the Buildroot configuration itself, or call make with `make savedefconfig BR2_DEFCONFIG=<path-to-defconfig>`.

The recommended place to store this defconfig is `configs/<boardname>_defconfig`. If you follow this recommendation, the configuration will be listed in `make help` and can be set again by running `make <boardname>_defconfig`.

Alternatively, you can copy the file to any other place and rebuild with `make defconfig BR2_DEFCONFIG=<path-to-defconfig-file>`.

## 9.4. Storing the configuration of other components

The configuration files for BusyBox, the Linux kernel, Barebox and uClibc should be stored as well if changed. For each of these components, a Buildroot configuration option exists to point to an input configuration file, e.g. `BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE`. To store their configuration, set these configuration options to a path where you want to save the configuration files, and then use the helper targets described below to actually store the configuration.

As explained in Section 9.1, “Recommended directory structure”, the recommended path to store these configuration files is `board/<company>/<boardname>/foo.config`.

Make sure that you create a configuration file before changing the `BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE` etc. options. Otherwise, Buildroot will try to access this config file, which doesn’t exist yet, and will fail. You can create the configuration file by running `make linux-menuconfig` etc.

Buildroot provides a few helper targets to make the saving of configuration files easier.

- `make linux-update-defconfig` saves the linux configuration to the path specified by `BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE`. It simplifies the config file by removing default values. However, this only works with kernels starting from 2.6.33. For earlier kernels, use `make linux-update-config`.
- `make busybox-update-config` saves the busybox configuration to the path specified by `BR2_PACKAGE_BUSYBOX_CONFIG`.
- `make uclibc-update-config` saves the uClibc configuration to the path specified by `BR2_UCLIBC_CONFIG`.
- `make barebox-update-defconfig` saves the barebox configuration to the path specified by `BR2_TARGET_BAREBOX_CUSTOM_CONFIG_FILE`.
- For at91bootstrap3, no helper exists so you have to copy the config file manually to `BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_CONFIG_FILE`.

## 9.5. Customizing the generated target filesystem

Besides changing the configuration through `make *config`, there are a few other ways to customize the resulting target filesystem.

The two recommended methods, which can co-exist, are root filesystem overlay(s) and post build script(s).

Root filesystem overlays (`BR2_ROOTFS_OVERLAY`)

  A filesystem overlay is a tree of files that is copied directly over the target filesystem after it has been built. To enable this feature, set config option `BR2_ROOTFS_OVERLAY` (in the `System configuration` menu) to the root of the overlay. You can even specify multiple overlays, space-separated. If you specify a relative path, it will be relative to the root of the Buildroot tree. Hidden directories of version control systems, like `.git`, `.svn`, `.hg`, etc., files called `.empty` and files ending in `~` are excluded from the copy.

  As shown in Section 9.1, “Recommended directory structure”, the recommended path for this overlay is `board/<company>/<boardname>/rootfs-overlay`.

Post-build scripts (`BR2_ROOTFS_POST_BUILD_SCRIPT`)

  Post-build scripts are shell scripts called after Buildroot builds all the selected software, but before the rootfs images are assembled. To enable this feature, specify a space-separated list of post-build scripts in config option `BR2_ROOTFS_POST_BUILD_SCRIPT` (in the `System configuration` menu). If you specify a relative path, it will be relative to the root of the Buildroot tree.

  Using post-build scripts, you can remove or modify any file in your target filesystem. You should, however, use this feature with care. Whenever you find that a certain package generates wrong or unneeded files, you should fix that package rather than work around it with some post-build cleanup scripts.

  As shown in Section 9.1, “Recommended directory structure”, the recommended path for this script is `board/<company>/<boardname>/post_build.sh`.

  The post-build scripts are run with the main Buildroot tree as current working directory. The path to the target filesystem is passed as the first argument to each script. If the config option `BR2_ROOTFS_POST_SCRIPT_ARGS` is not empty, these arguments will be passed to the script too. All the scripts will be passed the exact same set of arguments, it is not possible to pass different sets of arguments to each script.

  In addition, you may also use these environment variables:

  - `BR2_CONFIG`: the path to the Buildroot .config file
  - `HOST_DIR`, `STAGING_DIR`, `TARGET_DIR`: see Section 17.5.2, “`generic-package` reference”
  - `BUILD_DIR`: the directory where packages are extracted and built
  - `BINARIES_DIR`: the place where all binary files (aka images) are stored
  - `BASE_DIR`: the base output directory

Below two more methods of customizing the target filesystem are described, but they are not recommended.

Direct modification of the target filesystem

  For temporary modifications, you can modify the target filesystem directly and rebuild the image. The target filesystem is available under `output/target/`. After making your changes, run `make` to rebuild the target filesystem image.

  This method allows you to do anything to the target filesystem, but if you need to clean your Buildroot tree using `make clean`, these changes will be lost. Such cleaning is necessary in several cases, refer to Section 8.2, “Understanding when a full rebuild is necessary” for details. This solution is therefore only useful for quick tests: changes do not survive the `make clean` command. Once you have validated your changes, you should make sure that they will persist after a `make clean`, using a root filesystem overlay or a post-build script.

Custom target skeleton (`BR2_ROOTFS_SKELETON_CUSTOM`)

  The root filesystem image is created from a target skeleton, on top of which all packages install their files. The skeleton is copied to the target directory `output/target` before any package is built and installed. The default target skeleton provides the standard Unix filesystem layout and some basic init scripts and configuration files.

  If the default skeleton (available under `system/skeleton`) does not match your needs, you would typically use a root filesystem overlay or post-build script to adapt it. However, if the default skeleton is entirely different than what you need, using a custom skeleton may be more suitable.

  To enable this feature, enable config option `BR2_ROOTFS_SKELETON_CUSTOM` and set `BR2_ROOTFS_SKELETON_CUSTOM_PATH` to the path of your custom skeleton. Both options are available in the `System configuration` menu. If you specify a relative path, it will be relative to the root of the Buildroot tree.

  This method is not recommended because it duplicates the entire skeleton, which prevents taking advantage of the fixes or improvements brought to the default skeleton in later Buildroot releases.

### 9.5.1. Setting file permissions and ownership and adding custom devices nodes

Sometimes it is needed to set specific permissions or ownership on files or device nodes. For example, certain files may need to be owned by root. Since the post-build scripts are not run as root, you cannot do such changes from there unless you use an explicit fakeroot from the post-build script.

Instead, Buildroot provides support for so-called permission tables. To use this feature, set config option `BR2_ROOTFS_DEVICE_TABLE` to a space-separated list of permission tables, regular text files following the makedev syntax Chapter 22, Makedev syntax documentation.

If you are using a static device table (i.e. not using `devtmpfs`, `mdev`, or `(e)udev`) then you can add device nodes using the same syntax, in so-called device tables. To use this feature, set config option `BR2_ROOTFS_STATIC_DEVICE_TABLE` to a space-separated list of device tables.

As shown in Section 9.1, “Recommended directory structure”, the recommended location for such files is `board/<company>/<boardname>/`.

It should be noted that if the specific permissions or device nodes are related to a specific application, you should set variables `FOO_PERMISSIONS` and `FOO_DEVICES` in the package’s `.mk` file instead (see Section 17.5.2, “`generic-package` reference”).

## 9.6. Adding custom user accounts

Sometimes it is needed to add specific users in the target system. To cover this requirement, Buildroot provides support for so-called users tables. To use this feature, set config option `BR2_ROOTFS_USERS_TABLES` to a space-separated list of users tables, regular text files following the makeusers syntax Chapter 23, Makeusers syntax documentation.

As shown in Section 9.1, “Recommended directory structure”, the recommended location for such files is `board/<company>/<boardname>/`.

It should be noted that if the custom users are related to a specific application, you should set variable `FOO_USERS` in the package’s `.mk` file instead (see Section 17.5.2, “`generic-package` reference”).

## 9.7. Customization after the images have been created

While post-build scripts (Section 9.5, “Customizing the generated target filesystem”) are run before building the filesystem image, kernel and bootloader, post-image scripts can be used to perform some specific actions after all images have been created.

Post-image scripts can for example be used to automatically extract your root filesystem tarball in a location exported by your NFS server, or to create a special firmware image that bundles your root filesystem and kernel image, or any other custom action required for your project.

To enable this feature, specify a space-separated list of post-image scripts in config option `BR2_ROOTFS_POST_IMAGE_SCRIPT` (in the `System configuration` menu). If you specify a relative path, it will be relative to the root of the Buildroot tree.

Just like post-build scripts, post-image scripts are run with the main Buildroot tree as current working directory. The path to the `images` output directory is passed as the first argument to each script. If the config option `BR2_ROOTFS_POST_SCRIPT_ARGS` is not empty, these arguments will be passed to the script too. All the scripts will be passed the exact same set of arguments, it is not possible to pass different sets of arguments to each script.

Again just like for the post-build scripts, the scripts have access to the environment variables `BR2_CONFIG`, `HOST_DIR`, `STAGING_DIR`, `TARGET_DIR`, `BUILD_DIR`, `BINARIES_DIR` and `BASE_DIR`.

The post-image scripts will be executed as the user that executes Buildroot, which should normally not be the root user. Therefore, any action requiring root permissions in one of these scripts will require special handling (usage of fakeroot or sudo), which is left to the script developer.

## 9.8. Adding project-specific patches

It is sometimes useful to apply extra patches to packages - on top of those provided in Buildroot. This might be used to support custom features in a project, for example, or when working on a new architecture.

The `BR2_GLOBAL_PATCH_DIR` configuration option can be used to specify a space separated list of one or more directories containing package patches.

For a specific version `<packageversion>` of a specific package `<packagename>`, patches are applied from `BR2_GLOBAL_PATCH_DIR` as follows:

1. For every directory - `<global-patch-dir>` - that exists in `BR2_GLOBAL_PATCH_DIR`, a `<package-patch-dir>` will be determined as follows:

   - `<global-patch-dir>/<packagename>/<packageversion>/` if the directory exists.
   - Otherwise, `<global-patch-dir>/<packagename>` if the directory exists.

2. Patches will then be applied from a `<package-patch-dir>` as follows:

   - If a `series` file exists in the package directory, then patches are applied according to the `series` file;
   - Otherwise, patch files matching `<packagename>-*.patch` are applied in alphabetical order. So, to ensure they are applied in the right order, it is highly recommended to name the patch files like this: `<packagename>-<number>-<description>.patch`, where `<number>` refers to the apply order.

For information about how patches are applied for a package, see Section 18.2, “How patches are applied”

The `BR2_GLOBAL_PATCH_DIR` option is the preferred method for specifying a custom patch directory for packages. It can be used to specify a patch directory for any package in buildroot. It should also be used in place of the custom patch directory options that are available for packages such as U-Boot and Barebox. By doing this, it will allow a user to manage their patches from one top-level directory.

The exception to `BR2_GLOBAL_PATCH_DIR` being the preferred method for specifying custom patches is `BR2_LINUX_KERNEL_PATCH`. `BR2_LINUX_KERNEL_PATCH` should be used to specify kernel patches that are available at an URL. Note: `BR2_LINUX_KERNEL_PATCH` specifies kernel patches that are applied after patches available in `BR2_GLOBAL_PATCH_DIR`, as it is done from a post-patch hook of the Linux package.

## 9.9. Adding project-specific packages

In general, any new package should be added directly in the `package` directory and submitted to the Buildroot upstream project. How to add packages to Buildroot in general is explained in full detail in Chapter 17, Adding new packages to Buildroot and will not be repeated here. However, your project may need some proprietary packages that cannot be upstreamed. This section will explain how you can keep such project-specific packages in a project-specific directory.

As shown in Section 9.1, “Recommended directory structure”, the recommended location for project-specific packages is `package/<company>/`. If you are using the `BR2_EXTERNAL` feature (see Section 9.2, “Keeping customizations outside of Buildroot”) the recommended location is `$(BR2_EXTERNAL)/package/`.

However, Buildroot will not be aware of the packages in this location, unless we perform some additional steps. As explained in Chapter 17, Adding new packages to Buildroot, a package in Buildroot basically consists of two files: a `.mk` file (describing how to build the package) and a `Config.in` file (describing the configuration options for this package).

Buildroot will automatically include the `.mk` files in first-level subdirectories of the `package` directory (using the pattern `package/*/*.mk`). If we want Buildroot to include `.mk` files from deeper subdirectories (like `package/<company>/package1/`) then we simply have to add a `.mk` file in a first-level subdirectory that includes these additional `.mk` files. Therefore, create a file `package/<company>/<company>.mk` with following contents (assuming you have only one extra directory level below `package/<company>/`):

    include $(sort $(wildcard package/<company>/*/*.mk))

If you are using `BR2_EXTERNAL`, create a file `$(BR2_EXTERNAL)/external.mk` with following contents (again assuming only one extra level):

    include $(sort $(wildcard $(BR2_EXTERNAL)/package/*/*.mk))

For the `Config.in` files, create a file `package/<company>/Config.in` that includes the `Config.in` files of all your packages. An exhaustive list has to be provided since wildcards are not supported in the source command of kconfig. For example:

    source "package/<company>/package1/Config.in"
    source "package/<company>/package2/Config.in"

Include this new file `package/<company>/Config.in` from `package/Config.in`, preferably in a company-specific menu to make merges with future Buildroot versions easier.

If you are using `BR2_EXTERNAL`, create a file `$(BR2_EXTERNAL)/Config.in` with similar contents:

    source "$BR2_EXTERNAL/package/package1/Config.in"
    source "$BR2_EXTERNAL/package/package2/Config.in"

You do not have to add an include for this `$(BR2_EXTERNAL)/Config.in` file as it is included automatically.

## 9.10. Quick guide to storing your project-specific customizations

Earlier in this chapter, the different methods for making project-specific customizations have been described. This section will now summarize all this by providing step-by-step instructions to storing your project-specific customizations. Clearly, the steps that are not relevant to your project can be skipped.

1. `make menuconfig` to configure toolchain, packages and kernel.
2. `make linux-menuconfig` to update the kernel config, similar for other configuration like busybox, uclibc, …
3. `mkdir -p board/<manufacturer>/<boardname>`

4. Set the following options to `board/<manufacturer>/<boardname>/<package>.config` (as far as they are relevant):

   - `BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE`
   - `BR2_PACKAGE_BUSYBOX_CONFIG`
   - `BR2_UCLIBC_CONFIG`
   - `BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_CONFIG_FILE`
   - `BR2_TARGET_BAREBOX_CUSTOM_CONFIG_FILE`

5. Write the configuration files:

   - `make linux-update-defconfig`
   - `make busybox-update-config`
   - `make uclibc-update-config`
   - `cp <output>/build/at91bootstrap3-*/.config board/<manufacturer>/<boardname>/at91bootstrap3.config`
   - `make barebox-update-defconfig`
6. Create `board/<manufacturer>/<boardname>/rootfs-overlay/` and fill it with additional files you need on your rootfs, e.g. `board/<manufacturer>/<boardname>/rootfs-overlay/etc/inittab`. Set `BR2_ROOTFS_OVERLAY` to `board/<manufacturer>/<boardname>/rootfs-overlay`.
7. Create a post-build script `board/<manufacturer>/<boardname>/post_build.sh`. Set `BR2_ROOTFS_POST_BUILD_SCRIPT` to `board/<manufacturer>/<boardname>/post_build.sh`
8. If additional setuid permissions have to be set or device nodes have to be created, create `board/<manufacturer>/<boardname>/device_table.txt` and add that path to `BR2_ROOTFS_DEVICE_TABLE`.
9. If additional user accounts have to be created, create `board/<manufacturer>/<boardname>/users_table.txt` and add that path to `BR2_ROOTFS_USERS_TABLES`.
10. To add custom patches to certain packages, set `BR2_GLOBAL_PATCH_DIR` to `board/<manufacturer>/<boardname>/patches/` and add your patches for each package in a subdirectory named after the package. Each patch should be called `<packagename>-<num>-<description>.patch`.
11. Specifically for the Linux kernel, there also exists the option `BR2_LINUX_KERNEL_PATCH` with as main advantage that it can also download patches from a URL. If you do not need this, `BR2_GLOBAL_PATCH_DIR` is preferred. U-Boot, Barebox, at91bootstrap and at91bootstrap3 also have separate options, but these do not provide any advantage over `BR2_GLOBAL_PATCH_DIR` and will likely be removed in the future.
12. If you need to add project-specific packages, create `package/<manufacturer>/` and place your packages in that directory. Create an overall `<manufacturer>.mk` file that includes the `.mk` files of all your packages. Create an overall `Config.in` file that sources the `Config.in` files of all your packages. Include this `Config.in` file from Buildroot’s `package/Config.in` file.
13. `make savedefconfig` to save the buildroot configuration.
14. `cp defconfig configs/<boardname>_defconfig`

## Chapter 10. Frequently Asked Questions & Troubleshooting

## 10.1. The boot hangs after Starting network…

If the boot process seems to hang after the following messages (messages not necessarily exactly similar, depending on the list of packages selected):

    Freeing init memory: 3972K
    Initializing random number generator... done.
    Starting network...
    Starting dropbear sshd: generating rsa key... generating dsa key... OK

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 into the Buildroot configuration, in `System configuration`, modify `Run a getty (login prompt) after boot` and set the appropriate port and baud rate in the `getty options` submenu. This will automatically tune the `/etc/inittab` file of the generated system so that a shell starts on the correct serial port.

## 10.2. Why is there no compiler on the target?

It has been decided that support for the native compiler on the target would be stopped from the Buildroot-2012.11 release because:

- this feature was neither maintained nor tested, and often broken;
- this feature was only available for Buildroot toolchains;
- Buildroot mostly targets small or very small target hardware with limited resource onboard (CPU, ram, mass-storage), for which compiling on the target does not make much sense;
- Buildroot aims at easing the cross-compilation, making native compilation on the target unnecessary.

If you need a compiler on your target anyway, then Buildroot is not suitable for your purpose. In such case, you need a real distribution and you should opt for something like:

- openembedded
- yocto
- emdebian
- Fedora
- openSUSE ARM
- Arch Linux ARM
- …

## 10.3. Why are there no development files on the target?

Since there is no compiler available on the target (see Section 10.2, “Why is there no compiler on the target?”), it does not make sense to waste space with headers or static libraries.

Therefore, those files are always removed from the target since the Buildroot-2012.11 release.

## 10.4. Why is there no documentation on the target?

Because Buildroot mostly targets small or very small target hardware with limited resource onboard (CPU, ram, mass-storage), it does not make sense to waste space with the documentation data.

If you need documentation data on your target anyway, then Buildroot is not suitable for your purpose, and you should look for a real distribution (see: Section 10.2, “Why is there no compiler on the target?”).

## 10.5. Why are some packages not visible in the Buildroot config menu?

If a package exists in the Buildroot tree and does not appear in the config menu, this most likely means that some of the package’s dependencies are not met.

To know more about the dependencies of a package, search for the package symbol in the config menu (see Section 8.1, “make tips”).

Then, you may have to recursively enable several options (which correspond to the unmet dependencies) to finally be able to select the package.

If the package is not visible due to some unmet toolchain options, then you should certainly run a full rebuild (see Section 8.1, “make tips” for more explanations).

## 10.6. Why not use the target directory as a chroot directory?

There are plenty of reasons to not use the target directory a chroot one, among these:

- file ownerships, modes and permissions are not correctly set in the target directory;
- device nodes are not created in the target directory.

For these reasons, commands run through chroot, using the target directory as the new root, will most likely fail.

If you want to run the target filesystem inside a chroot, or as an NFS root, then use the tarball image generated in `images/` and extract it as root.

## 10.7. Why doesn’t Buildroot generate binary packages (.deb, .ipkg…)?

One feature that is often discussed on the Buildroot list is the general topic of "package management". To summarize, the idea would be to add some tracking of which Buildroot package installs what files, with the goals of:

- being able to remove files installed by a package when this package gets unselected from the menuconfig;
- being able to generate binary packages (ipk or other format) that can be installed on the target without re-generating a new root filesystem image.

In general, most people think it is easy to do: just track which package installed what and remove it when the package is unselected. However, it is much more complicated than that:

- It is not only about the `target/` directory, but also the sysroot in `host/usr/<tuple>/sysroot` and the `host/` directory itself. All files installed in those directories by various packages must be tracked.
- When a package is unselected from the configuration, it is not sufficient to remove just the files it installed. One must also remove all its reverse dependencies (i.e. packages relying on it) and rebuild all those packages. For example, package A depends optionally on the OpenSSL library. Both are selected, and Buildroot is built. Package A is built with crypto support using OpenSSL. Later on, OpenSSL gets unselected from the configuration, but package A remains (since OpenSSL is an optional dependency, this is possible.) If only OpenSSL files are removed, then the files installed by package A are broken: they use a library that is no longer present on the target. Although this is technically doable, it adds a lot of complexity to Buildroot, which goes against the simplicity we try to stick to.
- In addition to the previous problem, there is the case where the optional dependency is not even known to Buildroot. For example, package A in version 1.0 never used OpenSSL, but in version 2.0 it automatically uses OpenSSL if available. If the Buildroot .mk file hasn’t been updated to take this into account, then package A will not be part of the reverse dependencies of OpenSSL and will not be removed and rebuilt when OpenSSL is removed. For sure, the .mk file of package A should be fixed to mention this optional dependency, but in the mean time, you can have non-reproducible behaviors.
- The request is to also allow changes in the menuconfig to be applied on the output directory without having to rebuild everything from scratch. However, this is very difficult to achieve in a reliable way: what happens when the suboptions of a package are changed (we would have to detect this, and rebuild the package from scratch and potentially all its reverse dependencies), what happens if toolchain options are changed, etc. At the moment, what Buildroot does is clear and simple so its behaviour is very reliable and it is easy to support users. If configuration changes done in menuconfig are applied after the next make, then it has to work correctly and properly in all situations, and not have some bizarre corner cases. The risk is to get bug reports like "I have enabled package A, B and C, then ran make, then disabled package C and enabled package D and ran make, then re-enabled package C and enabled package E and then there is a build failure". Or worse "I did some configuration, then built, then did some changes, built, some more changes, built, some more changes, built, and now it fails, but I don’t remember all the changes I did and in which order". This will be impossible to support.

For all these reasons, the conclusion is that adding tracking of installed files to remove them when the package is unselected, or to generate a repository of binary packages, is something that is very hard to achieve reliably and will add a lot of complexity.

On this matter, the Buildroot developers make this position statement:

- Buildroot strives to make it easy to generate a root filesystem (hence the name, by the way.) That is what we want to make Buildroot good at: building root filesystems.
- Buildroot is not meant to be a distribution (or rather, a distribution generator.) It is the opinion of most Buildroot developers that this is not a goal we should pursue. We believe that there are other tools better suited to generate a distro than Buildroot is. For example, Open Embedded, or openWRT, are such tools.
- We prefer to push Buildroot in a direction that makes it easy (or even easier) to generate complete root filesystems. This is what makes Buildroot stands out in the crowd (among other things, of course!)
- We believe that for most embedded Linux systems, binary packages are not necessary, and potentially harmful. When binary packages are used, it means that the system can be partially upgraded, which creates an enormous number of possible combinations of package versions that should be tested before doing the upgrade on the embedded device. On the other hand, by doing complete system upgrades by upgrading the entire root filesystem image at once, the image deployed to the embedded system is guaranteed to really be the one that has been tested and validated.

## Chapter 11. Known issues

- It is not possible to pass extra linker options via `BR2_TARGET_LDFLAGS` if such options contain a `$` sign. For example, the following is known to break: `BR2_TARGET_LDFLAGS="-Wl,-rpath='$ORIGIN/../lib'"`
- The `ltp-testsuite` package does not build with the default uClibc configuration used by the Buildroot toolchain backend. The LTP testsuite uses several functions that are considered obsolete, such as sigset() and others. uClibc configuration options such as DO_XSI_MATH, UCLIBC_HAS_OBSOLETE_BSD_SIGNAL and UCLIBC_SV4_DEPRECATED are needed if one wants to build the `ltp-testsuite` package with uClibc. You need to either use a glibc or eglibc based toolchain, or enable the appropriate options in the uClibc configuration.
- The `xfsprogs` package does not build with the default uClibc configuration used by the Buildroot toolchain backend. You need to either use a glibc or eglibc based toolchain, or enable the appropriate options in the uClibc configuration.
- The `mrouted` package does not build with the default uClibc configuration used by the Buildroot toolchain backend. You need to either use a glibc or eglibc based toolchain, or enable the appropriate options in the uClibc configuration.
- The `libffi` package is not supported on the SuperH 2 and ARC architectures.
- The `prboom` package triggers a compiler failure with the SuperH 4 compiler from Sourcery CodeBench, version 2012.09.

## Chapter 12. Legal notice and licensing

## 12.1. Complying with open source licenses

All of the end products of Buildroot (toolchain, root filesystem, kernel, bootloaders) contain open source software, released under various licenses.

Using open source software gives you the freedom to build rich embedded systems, choosing from a wide range of packages, but also imposes some obligations that you must know and honour. Some licenses require you to publish the license text in the documentation of your product. Others require you to redistribute the source code of the software to those that receive your product.

The exact requirements of each license are documented in each package, and it is your responsibility (or that of your legal office) to comply with those requirements. To make this easier for you, Buildroot can collect for you some material you will probably need. To produce this material, after you have configured Buildroot with `make menuconfig`, `make xconfig` or `make gconfig`, run:

    make legal-info

Buildroot will collect legally-relevant material in your output directory, under the `legal-info/` subdirectory. There you will find:

- A `README` file, that summarizes the produced material and contains warnings about material that Buildroot could not produce.
- `buildroot.config`: this is the Buildroot configuration file that is usually produced with `make menuconfig`, and which is necessary to reproduce the build.
- The source code for all packages; this is saved in the `sources/` and `host-sources/` subdirectories for target and host packages respectively. The source code for packages that set `<PKG>_REDISTRIBUTE = NO` will not be saved. Patches applied to some packages by Buildroot are distributed with the Buildroot sources and are not duplicated in the `sources/` and `host-sources/` subdirectories.
- A manifest file (one for host and one for target packages) listing the configured packages, their version, license and related information. Some of this information might not be defined in Buildroot; such items are marked as "unknown".
- The license texts of all packages, in the `licenses/` and `host-licenses/` subdirectories for target and host packages respectively. If the license file(s) are not defined in Buildroot, the file is not produced and a warning in the `README` indicates this.

Please note that the aim of the `legal-info` feature of Buildroot is to produce all the material that is somehow relevant for legal compliance with the package licenses. Buildroot does not try to produce the exact material that you must somehow make public. Certainly, more material is produced than is needed for a strict legal compliance. For example, it produces the source code for packages released under BSD-like licenses, that you are not required to redistribute in source form.

Moreover, due to technical limitations, Buildroot does not produce some material that you will or may need, such as the toolchain source code and the Buildroot source code itself (including patches to packages for which source distribution is required). When you run `make legal-info`, Buildroot produces warnings in the `README` file to inform you of relevant material that could not be saved.

## 12.2. License abbreviations

Here is a list of the licenses that are most widely used by packages in Buildroot, with the name used in the manifest files:

- `GPLv2`: GNU General Public License, version 2;
- `GPLv2+`: GNU General Public License, version 2 or (at your option) any later version;
- `GPLv3`: GNU General Public License, version 3;
- `GPLv3+`: GNU General Public License, version 3 or (at your option) any later version;
- `GPL`: GNU General Public License (any version);
- `LGPLv2`: GNU Library General Public License, version 2;
- `LGPLv2+`: GNU Library General Public License, version 2 or (at your option) any later version;
- `LGPLv2.1`: GNU Lesser General Public License, version 2.1;
- `LGPLv2.1+`: GNU Lesser General Public License, version 2.1 or (at your option) any later version;
- `LGPLv3`: GNU Lesser General Public License, version 3;
- `LGPLv3+`: GNU Lesser General Public License, version 3 or (at your option) any later version;
- `LGPL`: GNU Lesser General Public License (any version);
- `BSD-4c`: Original BSD 4-clause license;
- `BSD-3c`: BSD 3-clause license;
- `BSD-2c`: BSD 2-clause license;
- `MIT`: MIT-style license.
- `Apache-2.0`: Apache License, version 2.0;

## 12.3. Complying with the Buildroot license

Buildroot itself is an open source software, released under the GNU General Public License, version 2 or (at your option) any later version. However, being a build system, it is not normally part of the end product: if you develop the root filesystem, kernel, bootloader or toolchain for a device, the code of Buildroot is only present on the development machine, not in the device storage.

Nevertheless, the general view of the Buildroot developers is that you should release the Buildroot source code along with the source code of other packages when releasing a product that contains GPL-licensed software. This is because the GNU GPL defines the "complete source code" for an executable work as "all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable". Buildroot is part of the scripts used to control compilation and installation of the executable, and as such it is considered part of the material that must be redistributed.

Keep in mind that this is only the Buildroot developers' opinion, and you should consult your legal department or lawyer in case of any doubt.

## Chapter 13. Beyond Buildroot

## 13.1. Boot the generated images

### 13.1.1. NFS boot

To achieve NFS-boot, enable tar root filesystem in the Filesystem images menu.

After a complete build, just run the following commands to setup the NFS-root directory:

    sudo tar -xavf /path/to/output_dir/rootfs.tar -C /path/to/nfs_root_dir

Remember to add this path to `/etc/exports`.

Then, you can execute a NFS-boot from your target.

## 13.2. Chroot

If you want to chroot in a generated image, then there are few thing you should be aware of:

- you should setup the new root from the tar root filesystem image;
- either the selected target architecture is compatible with your host machine, or you should use some `qemu-*` binary and correctly set it within the `binfmt` properties to be able to run the binaries built for the target on your host machine;
- Buildroot does not currently provide `host-qemu` and `binfmt` correctly built and set for that kind of use.

# Part III. Developer guide

## Chapter 14. How Buildroot works

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 toolchain (`gcc`, `binutils` and `uClibc`).

There is basically one Makefile per software package, and they are named with the `.mk` extension. Makefiles are split into many different parts.

- The `toolchain/` directory contains the Makefiles and associated files for all software related to the cross-compilation toolchain: `binutils`, `gcc`, `gdb`, `kernel-headers` and `uClibc`.
- The `arch/` directory contains the definitions for all the processor architectures that are supported by Buildroot.
- The `package/` directory contains the Makefiles and associated files for all user-space tools and libraries that Buildroot can compile and add to the target root filesystem. There is one sub-directory per package.
- The `linux/` directory contains the Makefiles and associated files for the Linux kernel.
- The `boot/` directory contains the Makefiles and associated files for the bootloaders supported by Buildroot.
- The `system/` directory contains support for system integration, e.g. the target filesystem skeleton and the selection of an init system.
- The `fs/` directory contains the Makefiles and associated files for software related to the generation of the target root filesystem image.

Each directory contains at least 2 files:

- `something.mk` is the Makefile that downloads, configures, compiles and installs the package `something`.
- `Config.in` is a part of the configuration tool description file. It describes the options related to the package.

The main Makefile performs the following steps (once the configuration is done):

- Create all the output directories: `staging`, `target`, `build`, etc. in the output directory (`output/` by default, another value can be specified using `O=`)
- Generate the toolchain target. 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.
- Generate all the targets listed in the `TARGETS` 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.

## Chapter 15. Coding style

Overall, these coding style rules are here to help you to add new files in Buildroot or refactor existing ones.

If you slightly modify some existing file, the important thing is to keep the consistency of the whole file, so you can:

- either follow the potentially deprecated coding style used in this file,
- or entirely rework it in order to make it comply with these rules.

## 15.1. `Config.in` file

`Config.in` files contain entries for almost anything configurable in Buildroot.

An entry has the following pattern:

    config BR2_PACKAGE_LIBFOO
            bool "libfoo"
            depends on BR2_PACKAGE_LIBBAZ
            select BR2_PACKAGE_LIBBAR
            help
              This is a comment that explains what libfoo is.

              http://foosoftware.org/libfoo/

- The `bool`, `depends on`, `select` and `help` lines are indented with one tab.
- The help text itself should be indented with one tab and two spaces.

The `Config.in` files are the input for the configuration tool used in Buildroot, which is the regular Kconfig. For further details about the Kconfig language, refer to http://kernel.org/doc/Documentation/kbuild/kconfig-language.txt.

## 15.2. The `.mk` file

- Header: The file starts with a header. It contains the module name, preferably in lowercase, enclosed between separators made of 80 hashes. A blank line is mandatory after the header:

      ################################################################################
      #
      # libfoo
      #
      ################################################################################

- Assignment: use `=` preceded and followed by one space:

      LIBFOO_VERSION = 1.0
      LIBFOO_CONF_OPTS += --without-python-support

  Do not align the `=` signs.

- Indentation: use tab only:

      define LIBFOO_REMOVE_DOC
              $(RM) -fr $(TARGET_DIR)/usr/share/libfoo/doc \
                      $(TARGET_DIR)/usr/share/man/man3/libfoo*
      endef

  Note that commands inside a `define` block should always start with a tab, so make recognizes them as commands.

- Optional dependency:

  - Prefer multi-line syntax.

    YES:

        ifeq ($(BR2_PACKAGE_PYTHON),y)
        LIBFOO_CONF_OPTS += --with-python-support
        LIBFOO_DEPENDENCIES += python
        else
        LIBFOO_CONF_OPTS += --without-python-support
        endif

    NO:

        LIBFOO_CONF_OPTS += --with$(if $(BR2_PACKAGE_PYTHON),,out)-python-support
        LIBFOO_DEPENDENCIES += $(if $(BR2_PACKAGE_PYTHON),python,)

  - Keep configure options and dependencies close together.

- Optional hooks: keep hook definition and assignment together in one if block.

  YES:

      ifneq ($(BR2_LIBFOO_INSTALL_DATA),y)
      define LIBFOO_REMOVE_DATA
              $(RM) -fr $(TARGET_DIR)/usr/share/libfoo/data
      endef
      LIBFOO_POST_INSTALL_TARGET_HOOKS += LIBFOO_REMOVE_DATA
      endif

  NO:

      define LIBFOO_REMOVE_DATA
              $(RM) -fr $(TARGET_DIR)/usr/share/libfoo/data
      endef

      ifneq ($(BR2_LIBFOO_INSTALL_DATA),y)
      LIBFOO_POST_INSTALL_TARGET_HOOKS += LIBFOO_REMOVE_DATA
      endif

## 15.3. The documentation

The documentation uses the asciidoc format.

For further details about the asciidoc syntax, refer to http://www.methods.co.nz/asciidoc/userguide.html.

## Chapter 16. Adding support for a particular board

Buildroot contains basic configurations for several publicly available hardware boards, so that users of such a board can easily build a system that is known to work. You are welcome to add support for other boards to Buildroot too.

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.

Once you have a known working configuration, run `make savedefconfig`. This will generate a minimal `defconfig` file at the root of the Buildroot source tree. Move this file into the `configs/` directory, and rename it `<boardname>_defconfig`.

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 board, or no default exists, we encourage you to send fixes to the corresponding upstream projects.

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 `board/<manufacturer>` and a subdirectory `board/<manufacturer>/<boardname>`. You can then store your patches and configurations in these directories, and reference them from the main Buildroot configuration. Refer to Chapter 9, Project-specific customization for more details.

## Chapter 17. Adding new packages to Buildroot

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.

## 17.1. Package directory

First of all, create a directory under the `package` directory for your software, for example `libfoo`.

Some packages have been grouped by topic in a sub-directory: `x11r7`, `efl` and `matchbox`. If your package fits in one of these categories, then create your package directory in these. New subdirectories are discouraged, however.

## 17.2. `Config.in` file

Then, create a file named `Config.in`. This file will contain the option descriptions related to our `libfoo` software that will be used and displayed in the configuration tool. It should basically contain:

    config BR2_PACKAGE_LIBFOO
            bool "libfoo"
            help
              This is a comment that explains what libfoo is.

              http://foosoftware.org/libfoo/

The `bool` line, `help` line and other metadata information about the configuration option must be indented with one tab. The help text itself should be indented with one tab and two spaces, and it must mention the upstream URL of the project.

You can add other sub-options into a `if BR2_PACKAGE_LIBFOO…endif` statement 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 http://kernel.org/doc/Documentation/kbuild/kconfig-language.txt

Finally you have to add your new `libfoo/Config.in` to `package/Config.in` (or in a category subdirectory if you decided to put your package in one of the existing categories). The files included there are sorted alphabetically per category and are NOT supposed to contain anything but the bare name of the package.

    source "package/libfoo/Config.in"

### 17.2.1. Choosing `depends on` or `select`

The `Config.in` file of your package must also ensure that dependencies are enabled. Typically, Buildroot uses the following rules:

- Use a `select` type of dependency for dependencies on libraries. These dependencies are generally not obvious and it therefore make sense to have the kconfig system ensure that the dependencies are selected. For example, the libgtk2 package uses `select BR2_PACKAGE_LIBGLIB2` to make sure this library is also enabled. The `select` keyword expresses the dependency with a backward semantic.
- Use a `depends on` type of dependency when the user really needs to be aware of the dependency. Typically, Buildroot uses this type of dependency for dependencies on target architecture, MMU support and toolchain options (see Section 17.2.2, “Dependencies on target and toolchain options”), or for dependencies on "big" things, such as the X.org system. The `depends on` keyword expresses the dependency with a forward semantic.

Note. The current problem with the kconfig language is that these two dependency semantics are not internally linked. Therefore, it may be possible to select a package, whom one of its dependencies/requirement is not met.

An example illustrates both the usage of `select` and `depends on`.

    config BR2_PACKAGE_ACL
            bool "acl"
            select BR2_PACKAGE_ATTR
            depends on BR2_LARGEFILE
            help
              POSIX Access Control Lists, which are used to define more
              fine-grained discretionary access rights for files and
              directories.
              This package also provides libacl.

              http://savannah.nongnu.org/projects/acl

    comment "acl needs a toolchain w/ largefile"
            depends on !BR2_LARGEFILE

Note that these two dependency types are only transitive with the dependencies of the same kind.

This means, in the following example:

    config BR2_PACKAGE_A
            bool "Package A"

    config BR2_PACKAGE_B
            bool "Package B"
            depends on BR2_PACKAGE_A

    config BR2_PACKAGE_C
            bool "Package C"
            depends on BR2_PACKAGE_B

    config BR2_PACKAGE_D
            bool "Package D"
            select BR2_PACKAGE_B

    config BR2_PACKAGE_E
            bool "Package E"
            select BR2_PACKAGE_D

- Selecting `Package C` will be visible if `Package B` has been selected, which in turn is only visible if `Package A` has been selected.
- Selecting `Package E` will select `Package D`, which will select `Package B`, it will not check for the dependencies of `Package B`, so it will not select `Package A`.
- Since `Package B` is selected but `Package A` is not, this violates the dependency of `Package B` on `Package A`. Therefore, in such a situation, the transitive dependency has to be added explicitly:

    config BR2_PACKAGE_D
            bool "Package D"
            select BR2_PACKAGE_B
            depends on BR2_PACKAGE_A

    config BR2_PACKAGE_E
            bool "Package E"
            select BR2_PACKAGE_D
            depends on BR2_PACKAGE_A

Overall, for package library dependencies, `select` should be preferred.

Note that such dependencies will ensure that the dependency option is also enabled, but not necessarily built before your package. To do so, the dependency also needs to be expressed in the `.mk` file of the package.

Further formatting details: see the coding style Section 15.1, “`Config.in` file”.

### 17.2.2. Dependencies on target and toolchain options

Many packages depend on certain options of the toolchain: the choice of C library, C++ support, largefile support, thread support, RPC support, IPv6 support, wchar support, or dynamic library support. Some packages can only be built on certain target architectures, or if an MMU is available in the processor.

These dependencies have to be expressed with the appropriate depends on statements in the Config.in file. Additionally, for dependencies on toolchain options, a `comment` should be displayed when the option is not enabled, so that the user knows why the package is not available. Dependencies on target architecture or MMU support should not be made visible in a comment: since it is unlikely that the user can freely choose another target, it makes little sense to show these dependencies explicitly.

The `comment` should only be visible if the `config` option itself would be visible when the toolchain option dependencies are met. This means that all other dependencies of the package (including dependencies on target architecture and MMU support) have to be repeated on the `comment` definition. To keep it clear, the `depends on` statement for these non-toolchain option should be kept separate from the `depends on` statement for the toolchain options. If there is a dependency on a config option in that same file (typically the main package) it is preferable to have a global `if … endif` construct rather than repeating the `depends on` statement on the comment and other config options.

The general format of a dependency `comment` for package foo is:

    foo needs a toolchain w/ featA, featB, featC

for example:

    aircrack-ng needs a toolchain w/ largefile, threads

or

    crda needs a toolchain w/ threads

Note that this text is kept brief on purpose, so that it will fit on a 80-character terminal.

The rest of this section enumerates the different target and toolchain options, the corresponding config symbols to depend on, and the text to use in the comment.

- Target architecture

  - Dependency symbol: `BR2_powerpc`, `BR2_mips`, … (see `arch/Config.in`)
  - Comment string: no comment to be added

- MMU support

  - Dependency symbol: `BR2_USE_MMU`
  - Comment string: no comment to be added

- Atomic instructions (whereby the architecture has instructions to perform some operations atomically, like LOCKCMPXCHG on x86)

  - Dependency symbol: `BR2_ARCH_HAS_ATOMICS`
  - Comment string: no comment to be added

- Kernel headers

  - Dependency symbol: `BR2_TOOLCHAIN_HEADERS_AT_LEAST_X_Y`, (replace `X_Y` with the proper version, see `toolchain/toolchain-common.in`)
  - Comment string: `headers >= X.Y` and/or `headers <= X.Y` (replace `X.Y` with the proper version)

- C library

  - Dependency symbol: `BR2_TOOLCHAIN_USES_GLIBC`, `BR2_TOOLCHAIN_USES_MUSL`, `BR2_TOOLCHAIN_USES_UCLIBC`
  - Comment string: for the C library, a slightly different comment text is used: `foo needs an (e)glibc toolchain`, or `foo needs an (e)glibc toolchain w/ C++`

- C++ support

  - Dependency symbol: `BR2_INSTALL_LIBSTDCPP`
  - Comment string: `C++`

- largefile support

  - Dependency symbol: `BR2_LARGEFILE`
  - Comment string: `largefile`

- thread support

  - Dependency symbol: `BR2_TOOLCHAIN_HAS_THREADS`
  - Comment string: `threads` (unless `BR2_TOOLCHAIN_HAS_THREADS_NPTL` is also needed, in which case, specifying only `NPTL` is sufficient)

- NPTL thread support

  - Dependency symbol: `BR2_TOOLCHAIN_HAS_THREADS_NPTL`
  - Comment string: `NPTL`

- RPC support

  - Dependency symbol: `BR2_TOOLCHAIN_HAS_NATIVE_RPC`
  - Comment string: `RPC`

- IPv6 support

  - Dependency symbol: `BR2_INET_IPV6`
  - Comment string: `IPv6` (lowercase v)

- wchar support

  - Dependency symbol: `BR2_USE_WCHAR`
  - Comment string: `wchar`

- dynamic library

  - Dependency symbol: `!BR2_PREFER_STATIC_LIB`
  - Comment string: `dynamic library`

### 17.2.3. Dependencies on a Linux kernel built by buildroot

Some packages need a Linux kernel to be built by buildroot. These are typically kernel modules or firmware. A comment should be added in the Config.in file to express this dependency, similar to dependencies on toolchain options. The general format is:

    foo needs a Linux kernel to be built

If there is a dependency on both toolchain options and the Linux kernel, use this format:

    foo needs a toolchain w/ featA, featB, featC and a Linux kernel to be built

### 17.2.4. Dependencies on udev /dev management

If a package needs udev /dev management, it should depend on symbol `BR2_PACKAGE_HAS_UDEV`, and the following comment should be added:

    foo needs udev /dev management

If there is a dependency on both toolchain options and udev /dev management, use this format:

    foo needs udev /dev management and a toolchain w/ featA, featB, featC

### 17.2.5. Dependencies on features provided by virtual packages

Some features can be provided by more than one package, such as the openGL libraries.

See Section 17.11, “Infrastructure for virtual packages” for more on the virtual packages.

See Chapter 25, List of virtual packages for the symbols to depend on if your package depends on a feature provided by a virtual package.

## 17.3. The `.mk` file

Finally, here’s the hardest part. Create a file named `libfoo.mk`. It describes how the package should be downloaded, configured, built, installed, etc.

Depending on the package type, the `.mk` file must be written in a different way, using different infrastructures:

- Makefiles for generic packages (not using autotools or CMake): These are based on an infrastructure similar to the one used for autotools-based packages, but require a little more work from the developer. They specify what should be done for the configuration, compilation and installation 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. We cover them through in a tutorial Section 17.5.1, “`generic-package` tutorial” and a reference Section 17.5.2, “`generic-package` reference”.
- Makefiles for autotools-based software (autoconf, automake, etc.): We provide a dedicated infrastructure for such packages, since autotools is a very common build system. This infrastructure must be used for new packages that rely on the autotools as their build system. We cover them through a tutorial Section 17.6.1, “`autotools-package` tutorial” and reference Section 17.6.2, “`autotools-package` reference”.
- Makefiles for cmake-based software: We provide a dedicated infrastructure for such packages, as CMake is a more and more commonly used build system and has a standardized behaviour. This infrastructure must be used for new packages that rely on CMake. We cover them through a tutorial Section 17.7.1, “`cmake-package` tutorial” and reference Section 17.7.2, “`cmake-package` reference”.
- Makefiles for Python modules: We have a dedicated infrastructure for Python modules that use either the `distutils` or the `setuptools` mechanism. We cover them through a tutorial Section 17.8.1, “`python-package` tutorial” and a reference Section 17.8.2, “`python-package` reference”.
- Makefiles for Lua modules: We have a dedicated infrastructure for Lua modules available through the LuaRocks web site. We cover them through a tutorial Section 17.9.1, “`luarocks-package` tutorial” and a reference Section 17.9.2, “`luarocks-package` reference”.

Further formatting details: see the writing rules Section 15.2, “The `.mk` file”.

## 17.4. The `.hash` file

Optionally, you can add a third file, named `libfoo.hash`, that contains the hashes of the downloaded files for the `libfoo` package.

The hashes stored in that file are used to validate the integrity of the downloaded files.

The format of this file is one line for each file for which to check the hash, each line being space-separated, with these three fields:

- the type of hash, one of:

  - `sha1`, `sha224`, `sha256`, `sha384`, `sha512`

- the hash of the file:

  - for `sha1`, 40 hexadecimal characters
  - for `sha224`, 56 hexadecimal characters
  - for `sha256`, 64 hexadecimal characters
  - for `sha384`, 96 hexadecimal characters
  - for `sha512`, 128 hexadecimal characters
- the name of the file, without any directory component

Lines starting with a `#` sign are considered comments, and ignored. Empty lines are ignored.

There can be more than one hash for a single file, each on its own line. In this case, all hashes must match.

Ideally, the hashes stored in this file should match the hashes published by upstream, e.g. on their website, in the e-mail announcement… If upstream provides more than one type of hash (say, `sha1` and `sha512`), then it is best to add all those hashes in the `.hash` file. If upstream does not provide any hash, then compute at least one yourself, and mention this in a comment line above the hashes.

Note: the number of spaces does not matter, so one can use spaces to properly align the different fields.

The example below defines a `sha1` and a `sha256` published by upstream for the main `libfoo-1.2.3.tar.bz2` tarball, plus two locally-computed hashes, a `sha256` for a downloaded patch, and a `sha1` for a downloaded binary blob:

    # Hashes from: http://www.foosoftware.org/download/libfoo-1.2.3.tar.bz2.{sha1,sha256}:
    sha1   486fb55c3efa71148fe07895fd713ea3a5ae343a                         libfoo-1.2.3.tar.bz2
    sha256 efc8103cc3bcb06bda6a781532d12701eb081ad83e8f90004b39ab81b65d4369 libfoo-1.2.3.tar.bz2

    # No upstream hashes for the following:
    sha256 ff52101fb90bbfc3fe9475e425688c660f46216d7e751c4bbdb1dc85cdccacb9 libfoo-fix-blabla.patch
    sha1   2d608f3c318c6b7557d551a5a09314f03452f1a1                         libfoo-data.bin

If the `.hash` file is present, and it contains one or more hashes for a downloaded file, the hash(es) computed by Buildroot (after download) must match the hash(es) stored in the `.hash` file. If one or more hashes do not match, Buildroot considers this an error, deletes the downloaded file, and aborts.

If the `.hash` file is present, but it does not contain a hash for a downloaded file, no check is done for that file. If you set the environment variable `BR2_ENFORCE_CHECK_HASH` to a non-empty value, and there is no hash for a downloaded file, Buildroot considers this an error, deletes the downloaded file, and aborts.

If the `.hash` file is missing, then no check is done at all.

## 17.5. Infrastructure for packages with specific build systems

By packages with specific build systems we mean all the packages whose build system is not one of the standard ones, such as autotools or CMake. This typically includes packages whose build system is based on hand-written Makefiles or shell scripts.

### 17.5.1. `generic-package` tutorial

    01: ################################################################################
    02: #
    03: # libfoo
    04: #
    05: ################################################################################
    06:
    07: LIBFOO_VERSION = 1.0
    08: LIBFOO_SOURCE = libfoo-$(LIBFOO_VERSION).tar.gz
    09: LIBFOO_SITE = http://www.foosoftware.org/download
    10: LIBFOO_LICENSE = GPLv3+
    11: LIBFOO_LICENSE_FILES = COPYING
    12: LIBFOO_INSTALL_STAGING = YES
    13: LIBFOO_CONFIG_SCRIPTS = libfoo-config
    14: LIBFOO_DEPENDENCIES = host-libaaa libbbb
    15:
    16: define LIBFOO_BUILD_CMDS
    17:     $(MAKE) CC="$(TARGET_CC)" LD="$(TARGET_LD)" -C $(@D) all
    18: endef
    19:
    20: define LIBFOO_INSTALL_STAGING_CMDS
    21:     $(INSTALL) -D -m 0755 $(@D)/libfoo.a $(STAGING_DIR)/usr/lib/libfoo.a
    22:     $(INSTALL) -D -m 0644 $(@D)/foo.h $(STAGING_DIR)/usr/include/foo.h
    23:     $(INSTALL) -D -m 0755 $(@D)/libfoo.so* $(STAGING_DIR)/usr/lib
    24: endef
    25:
    26: define LIBFOO_INSTALL_TARGET_CMDS
    27:     $(INSTALL) -D -m 0755 $(@D)/libfoo.so* $(TARGET_DIR)/usr/lib
    28:     $(INSTALL) -d -m 0755 $(TARGET_DIR)/etc/foo.d
    29: endef
    30:
    31: define LIBFOO_DEVICES
    32:     /dev/foo  c  666  0  0  42  0  -  -  -
    33: endef
    34:
    35: define LIBFOO_PERMISSIONS
    36:     /bin/foo  f  4755  0  0  -  -  -  -  -
    37: endef
    38:
    39: define LIBFOO_USERS
    40:     foo -1 libfoo -1 * - - - LibFoo daemon
    41: endef
    42:
    43: $(eval $(generic-package))

The Makefile begins on line 7 to 11 with metadata information: the version of the package (`LIBFOO_VERSION`), the name of the tarball containing the package (`LIBFOO_SOURCE`) (xz-ed tarball recommended) the Internet location at which the tarball can be downloaded from (`LIBFOO_SITE`), the license (`LIBFOO_LICENSE`) and file with the license text (`LIBFOO_LICENSE_FILES`). All variables must start with the same prefix, `LIBFOO_` in this case. This prefix is always the uppercased version of the package name (see below to understand where the package name is defined).

On line 12, 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 `LIBFOO_INSTALL_STAGING_CMDS` variable will be executed.

On line 13, we specify that there is some fixing to be done to some of the libfoo-config files that were installed during `LIBFOO_INSTALL_STAGING_CMDS` phase. These *-config files are executable shell script files that are located in $(STAGING_DIR)/usr/bin directory and are executed by other 3rd party packages to find out the location and the linking flags of this particular package.

The problem is that all these *-config files by default give wrong, host system linking flags that are unsuitable for cross-compiling.

For example: -I/usr/include instead of -I$(STAGING_DIR)/usr/include or: -L/usr/lib instead of -L$(STAGING_DIR)/usr/lib

So some sed magic is done to these scripts to make them give correct flags. The argument to be given to `LIBFOO_CONFIG_SCRIPTS` is the file name(s) of the shell script(s) needing fixing. All these names are relative to $(STAGING_DIR)/usr/bin and if needed multiple names can be given.

In addition, the scripts listed in `LIBFOO_CONFIG_SCRIPTS` are removed from `$(TARGET_DIR)/usr/bin`, since they are not needed on the target.

Example 17.1. Config script: divine package

Package divine installs shell script $(STAGING_DIR)/usr/bin/divine-config.

So its fixup would be:

    DIVINE_CONFIG_SCRIPTS = divine-config

Example 17.2. Config script: imagemagick package:

Package imagemagick installs the following scripts: $(STAGING_DIR)/usr/bin/{Magick,Magick++,MagickCore,MagickWand,Wand}-config

So it’s fixup would be:

    IMAGEMAGICK_CONFIG_SCRIPTS = \
       Magick-config Magick++-config \
       MagickCore-config MagickWand-config Wand-config

On line 14, 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 `host-` prefix) or packages for the host (with the `host-`) prefix). Buildroot will ensure that all these packages are built and installed before the current package starts its configuration.

The rest of the Makefile, lines 16..29, defines what should be done at the different steps of the package configuration, compilation and installation. `LIBFOO_BUILD_CMDS` tells what steps should be performed to build the package. `LIBFOO_INSTALL_STAGING_CMDS` tells what steps should be performed to install the package in the staging space. `LIBFOO_INSTALL_TARGET_CMDS` tells what steps should be performed to install the package in the target space.

All these steps rely on the `$(@D)` variable, which contains the directory where the source code of the package has been extracted.

On line 31..33, we define a device-node file used by this package (`LIBFOO_DEVICES`).

On line 35..37, we define the permissions to set to specific files installed by this package (`LIBFOO_PERMISSIONS`).

On lines 39..41, we define a user that is used by this package (e.g. to run a daemon as non-root) (`LIBFOO_USERS`).

Finally, on line 43, we call the `generic-package` function, which generates, according to the variables defined previously, all the Makefile code necessary to make your package working.

### 17.5.2. `generic-package` reference

There are two variants of the generic target. The `generic-package` macro is used for packages to be cross-compiled for the target. The `host-generic-package` macro is used for host packages, natively compiled for the host. It is possible to call both of them in a single `.mk` file: once to create the rules to generate a target package and once to create the rules to generate a host package:

    $(eval $(generic-package))
    $(eval $(host-generic-package))

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 `libfoo`, then the name of the package for the target is also `libfoo`, while the name of the package for the host is `host-libfoo`. These names should be used in the DEPENDENCIES variables of other packages, if they depend on `libfoo` or `host-libfoo`.

The call to the `generic-package` and/or `host-generic-package` macro must be at the end of the `.mk` file, after all variable definitions.

For the target package, the `generic-package` uses the variables defined by the .mk file and prefixed by the uppercased package name: `LIBFOO_*`. `host-generic-package` uses the `HOST_LIBFOO_*` variables. For some variables, if the `HOST_LIBFOO_` prefixed variable doesn’t exist, the package infrastructure uses the corresponding variable prefixed by `LIBFOO_`. This is done for variables that are likely to have the same value for both the target and host packages. See below for details.

The list of variables that can be set in a `.mk` file to give metadata information is (assuming the package name is `libfoo`) :

- `LIBFOO_VERSION`, mandatory, must contain the version of the package. Note that if `HOST_LIBFOO_VERSION` doesn’t exist, it is assumed to be the same as `LIBFOO_VERSION`. It can also be a revision number, branch or tag for packages that are fetched directly from their revision control system. Examples: `LIBFOO_VERSION = 0.1.2` `LIBFOO_VERSION = cb9d6aa9429e838f0e54faa3d455bcbab5eef057` `LIBFOO_VERSION = stable`
- `LIBFOO_SOURCE` may contain the name of the tarball of the package. If `HOST_LIBFOO_SOURCE` is not specified, it defaults to `LIBFOO_SOURCE`. If none are specified, then the value is assumed to be `libfoo-$(LIBFOO_VERSION).tar.gz`. Example: `LIBFOO_SOURCE = foobar-$(LIBFOO_VERSION).tar.bz2`
- `LIBFOO_PATCH` may contain a space-separated list of patch file names, that will be downloaded from the same location as the tarball indicated in `LIBFOO_SOURCE`, and then applied to the package source code. If `HOST_LIBFOO_PATCH` is not specified, it defaults to `LIBFOO_PATCH`. Note that patches that are included in Buildroot itself use a different mechanism: all files of the form `<packagename>-*.patch` present in the package directory inside Buildroot will be applied to the package after extraction (see patching a package Chapter 18, Patching a package). Finally, patches listed in the `LIBFOO_PATCH` variable are applied before the patches stored in the Buildroot package directory.
- `LIBFOO_SITE` provides the location of the package, which can be a URL or a local filesystem path. HTTP, FTP and SCP are supported URL types for retrieving package tarballs. Git, Subversion, Mercurial, and Bazaar are supported URL types for retrieving packages directly from source code management systems. There is a helper function to make it easier to download source tarballs from GitHub (refer to Section 17.16.2, “How to add a package from GitHub” for details). A filesystem path may be used to specify either a tarball or a directory containing the package source code. See `LIBFOO_SITE_METHOD` below for more details on how retrieval works. Note that SCP URLs should be of the form `scp://[user@]host:filepath`, and that filepath is relative to the user’s home directory, so you may want to prepend the path with a slash for absolute paths: `scp://[user@]host:/absolutepath`. If `HOST_LIBFOO_SITE` is not specified, it defaults to `LIBFOO_SITE`. Examples: `LIBFOO_SITE=http://www.libfoosoftware.org/libfoo` `LIBFOO_SITE=http://svn.xiph.org/trunk/Tremor/` `LIBFOO_SITE=/opt/software/libfoo.tar.gz` `LIBFOO_SITE=$(TOPDIR)/../src/libfoo/`
- `LIBFOO_EXTRA_DOWNLOADS` lists a number of additional files that Buildroot should download from `LIBFOO_SITE` in addition to the main `LIBFOO_SOURCE` (which usually is a tarball). Buildroot will not do anything with those additional files, except download files: it will be up to the package recipe to use them from `$(BR2_DL_DIR)`.

- `LIBFOO_SITE_METHOD` determines the method used to fetch or copy the package source code. In many cases, Buildroot guesses the method from the contents of `LIBFOO_SITE` and setting `LIBFOO_SITE_METHOD` is unnecessary. When `HOST_LIBFOO_SITE_METHOD` is not specified, it defaults to the value of `LIBFOO_SITE_METHOD`. The possible values of `LIBFOO_SITE_METHOD` are:

  - `wget` for normal FTP/HTTP downloads of tarballs. Used by default when `LIBFOO_SITE` begins with `http://`, `https://` or `ftp://`.
  - `scp` for downloads of tarballs over SSH with scp. Used by default when `LIBFOO_SITE` begins with `scp://`.
  - `svn` for retrieving source code from a Subversion repository. Used by default when `LIBFOO_SITE` begins with `svn://`. When a `http://` Subversion repository URL is specified in `LIBFOO_SITE`, one must specify `LIBFOO_SITE_METHOD=svn`. Buildroot performs a checkout which is preserved as a tarball in the download cache; subsequent builds use the tarball instead of performing another checkout.
  - `cvs` for retrieving source code from a CVS repository. Used by default when `LIBFOO_SITE` begins with `cvs://`. The downloaded source code is cached as with the `svn` method. Only anonymous pserver mode is supported. `LIBFOO_SITE` must contain the source URL as well as the remote repository directory. The module is the package name. `LIBFOO_VERSION` is mandatory and must be a timestamp.
  - `git` for retrieving source code from a Git repository. Used by default when `LIBFOO_SITE` begins with `git://`. The downloaded source code is cached as with the `svn` method.
  - `hg` for retrieving source code from a Mercurial repository. One must specify `LIBFOO_SITE_METHOD=hg` when `LIBFOO_SITE` contains a Mercurial repository URL. The downloaded source code is cached as with the `svn` method.
  - `bzr` for retrieving source code from a Bazaar repository. Used by default when `LIBFOO_SITE` begins with `bzr://`. The downloaded source code is cached as with the `svn` method.
  - `file` for a local tarball. One should use this when `LIBFOO_SITE` specifies a package tarball as a local filename. Useful for software that isn’t available publicly or in version control.
  - `local` for a local source code directory. One should use this when `LIBFOO_SITE` specifies a local directory path containing the package source code. Buildroot copies the contents of the source directory into the package’s build directory.
- `LIBFOO_DEPENDENCIES` 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, `HOST_LIBFOO_DEPENDENCIES` lists the dependencies for the current host package.
- `LIBFOO_PROVIDES` lists all the virtual packages `libfoo` is an implementation of. See Section 17.11, “Infrastructure for virtual packages”.
- `LIBFOO_INSTALL_STAGING` can be set to `YES` or `NO` (default). If set to `YES`, then the commands in the `LIBFOO_INSTALL_STAGING_CMDS` variables are executed to install the package into the staging directory.
- `LIBFOO_INSTALL_TARGET` can be set to `YES` (default) or `NO`. If set to `YES`, then the commands in the `LIBFOO_INSTALL_TARGET_CMDS` variables are executed to install the package into the target directory.
- `LIBFOO_CONFIG_SCRIPTS` lists the names of the files in $(STAGING_DIR)/usr/bin that need some special fixing to make them cross-compiling friendly. Multiple file names separated by space can be given and all are relative to $(STAGING_DIR)/usr/bin. The files listed in `LIBFOO_CONFIG_SCRIPTS` are also removed from `$(TARGET_DIR)/usr/bin` since they are not needed on the target.
- `LIBFOO_DEVICES` lists the device files to be created by Buildroot when using the static device table. The syntax to use is the makedevs one. You can find some documentation for this syntax in the Chapter 22, Makedev syntax documentation. This variable is optional.
- `LIBFOO_PERMISSIONS` lists the changes of permissions to be done at the end of the build process. The syntax is once again the makedevs one. You can find some documentation for this syntax in the Chapter 22, Makedev syntax documentation. This variable is optional.
- `LIBFOO_USERS` lists the users to create for this package, if it installs a program you want to run as a specific user (e.g. as a daemon, or as a cron-job). The syntax is similar in spirit to the makedevs one, and is described in the Chapter 23, Makeusers syntax documentation. This variable is optional.
- `LIBFOO_LICENSE` defines the license (or licenses) under which the package is released. This name will appear in the manifest file produced by `make legal-info`. If the license appears in the following list Section 12.2, “License abbreviations”, use the same string to make the manifest file uniform. Otherwise, describe the license in a precise and concise way, avoiding ambiguous names such as `BSD` which actually name a family of licenses. This variable is optional. If it is not defined, `unknown` will appear in the `license` field of the manifest file for this package.
- `LIBFOO_LICENSE_FILES` is a space-separated list of files in the package tarball that contain the license(s) under which the package is released. `make legal-info` copies all of these files in the `legal-info` directory. See Chapter 12, Legal notice and licensing for more information. This variable is optional. If it is not defined, a warning will be produced to let you know, and `not saved` will appear in the `license files` field of the manifest file for this package.
- `LIBFOO_REDISTRIBUTE` can be set to `YES` (default) or `NO` to indicate if the package source code is allowed to be redistributed. Set it to `NO` for non-opensource packages: Buildroot will not save the source code for this package when collecting the `legal-info`.
- `LIBFOO_FLAT_STACKSIZE` defines the stack size of an application built into the FLAT binary format. The application stack size on the NOMMU architecture processors can’t be enlarged at run time. The default stack size for the FLAT binary format is only 4k bytes. If the application consumes more stack, append the required number here.

The recommended way to define these variables is to use the following syntax:

    LIBFOO_VERSION = 2.32

Now, the variables that define what should be performed at the different steps of the build process.

- `LIBFOO_EXTRACT_CMDS` lists the actions to be performed to extract the package. This is generally not needed as tarballs are automatically handled by Buildroot. However, if the package uses a non-standard archive format, such as a ZIP or RAR file, or has a tarball with a non-standard organization, this variable allows to override the package infrastructure default behavior.
- `LIBFOO_CONFIGURE_CMDS` lists the actions to be performed to configure the package before its compilation.
- `LIBFOO_BUILD_CMDS` lists the actions to be performed to compile the package.
- `HOST_LIBFOO_INSTALL_CMDS` lists 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 `$(HOST_DIR)`. All files, including development files such as headers should be installed, since other packages might be compiled on top of this package.
- `LIBFOO_INSTALL_TARGET_CMDS` lists the actions to be performed to install the package to the target directory, when the package is a target package. The package must install its files to the directory given by `$(TARGET_DIR)`. Only the files required for execution of the package have to be installed. Header files, static libraries and documentation will be removed again when the target filesystem is finalized.
- `LIBFOO_INSTALL_STAGING_CMDS` lists 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 `$(STAGING_DIR)`. All development files should be installed, since they might be needed to compile other packages.
- `LIBFOO_INSTALL_IMAGES_CMDS` lists the actions to be performed to install the package to the images directory, when the package is a target package. The package must install its files to the directory given by `$(BINARIES_DIR)`. Only files that are binary images (aka images) that do not belong in the `TARGET_DIR` but are necessary for booting the board should be placed here. For example, a package should utilize this step if it has binaries which would be similar to the kernel image, bootloader or root filesystem images.
- `LIBFOO_INSTALL_INIT_SYSV` and `LIBFOO_INSTALL_INIT_SYSTEMD` list the actions to install init scripts either for the systemV-like init systems (busybox, sysvinit, etc.) or for the systemd units. These commands will be run only when the relevant init system is installed (i.e. if systemd is selected as the init system in the configuration, only `LIBFOO_INSTALL_INIT_SYSTEMD` will be run).

The preferred way to define these variables is:

    define LIBFOO_CONFIGURE_CMDS
            action 1
            action 2
            action 3
    endef

In the action definitions, you can use the following variables:

- `$(@D)`, which contains the directory in which the package source code has been uncompressed.
- `$(TARGET_CC)`, `$(TARGET_LD)`, etc. to get the target cross-compilation utilities
- `$(TARGET_CROSS)` to get the cross-compilation toolchain prefix
- Of course the `$(HOST_DIR)`, `$(STAGING_DIR)` and `$(TARGET_DIR)` variables to install the packages properly.

Finally, you can also use hooks. See Section 17.14, “Hooks available in the various build steps” for more information.

## 17.6. Infrastructure for autotools-based packages

### 17.6.1. `autotools-package` tutorial

First, let’s see how to write a `.mk` file for an autotools-based package, with an example :

    01: ################################################################################
    02: #
    03: # libfoo
    04: #
    05: ################################################################################
    06:
    07: LIBFOO_VERSION = 1.0
    08: LIBFOO_SOURCE = libfoo-$(LIBFOO_VERSION).tar.gz
    09: LIBFOO_SITE = http://www.foosoftware.org/download
    10: LIBFOO_INSTALL_STAGING = YES
    11: LIBFOO_INSTALL_TARGET = NO
    12: LIBFOO_CONF_OPTS = --disable-shared
    13: LIBFOO_DEPENDENCIES = libglib2 host-pkgconf
    14:
    15: $(eval $(autotools-package))

On line 7, we declare the version of the package.

On line 8 and 9, we declare the name of the tarball (xz-ed tarball recommended) and the location of the tarball on the Web. Buildroot will automatically download the tarball from this location.

On line 10, we tell Buildroot to install the package to the staging directory. The staging directory, located in `output/staging/` 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 `make install` command.

On line 11, we tell Buildroot to not install the package to the target directory. This directory contains what will become the root filesystem running on the target. For purely static libraries, it is not necessary to install them in the target directory because they will not be used at runtime. By default, target installation is enabled; setting this variable to NO is almost never needed. Also by default, packages are installed in this location using the `make install` command.

On line 12, we tell Buildroot to pass a custom configure option, that will be passed to the `./configure` script before configuring and building the package.

On line 13, we declare our dependencies, so that they are built before the build process of our package starts.

Finally, on line line 15, we invoke the `autotools-package` macro that generates all the Makefile rules that actually allows the package to be built.

### 17.6.2. `autotools-package` reference

The main macro of the autotools package infrastructure is `autotools-package`. It is similar to the `generic-package` macro. The ability to have target and host packages is also available, with the `host-autotools-package` macro.

Just like the generic infrastructure, the autotools infrastructure works by defining a number of variables before calling the `autotools-package` macro.

First, all the package metadata information variables that exist in the generic infrastructure also exist in the autotools infrastructure: `LIBFOO_VERSION`, `LIBFOO_SOURCE`, `LIBFOO_PATCH`, `LIBFOO_SITE`, `LIBFOO_SUBDIR`, `LIBFOO_DEPENDENCIES`, `LIBFOO_INSTALL_STAGING`, `LIBFOO_INSTALL_TARGET`.

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.

- `LIBFOO_SUBDIR` 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 `HOST_LIBFOO_SUBDIR` is not specified, it defaults to `LIBFOO_SUBDIR`.
- `LIBFOO_CONF_ENV`, to specify additional environment variables to pass to the configure script. By default, empty.
- `LIBFOO_CONF_OPTS`, to specify additional configure options to pass to the configure script. By default, empty.
- `LIBFOO_MAKE`, to specify an alternate `make` command. This is typically useful when parallel make is enabled in the configuration (using `BR2_JLEVEL`) but that this feature should be disabled for the given package, for one reason or another. By default, set to `$(MAKE)`. If parallel building is not supported by the package, then it should be set to `LIBFOO_MAKE=$(MAKE1)`.
- `LIBFOO_MAKE_ENV`, to specify additional environment variables to pass to make in the build step. These are passed before the `make` command. By default, empty.
- `LIBFOO_MAKE_OPTS`, to specify additional variables to pass to make in the build step. These are passed after the `make` command. By default, empty.
- `LIBFOO_AUTORECONF`, 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 `YES` and `NO`. By default, the value is `NO`
- `LIBFOO_AUTORECONF_ENV`, to specify additional environment variables to pass to the autoreconf program if `LIBFOO_AUTORECONF=YES`. These are passed in the environment of the autoreconf command. By default, empty.
- `LIBFOO_AUTORECONF_OPTS` to specify additional options passed to the autoreconf program if `LIBFOO_AUTORECONF=YES`. By default, empty.
- `LIBFOO_GETTEXTIZE`, tells whether the package should be gettextized or not (i.e. if the package uses a different gettext version than Buildroot provides, and it is needed to run gettextize.) Only valid when `LIBFOO_AUTORECONF=YES`. Valid values are `YES` and `NO`. The default is `NO`.
- `LIBFOO_GETTEXTIZE_OPTS`, to specify additional options passed to the gettextize program, if `LIBFOO_GETTEXTIZE=YES`. You may use that if, for example, the `.po` files are not located in the standard place (i.e. in `po/` at the root of the package.) By default, -f.
- `LIBFOO_LIBTOOL_PATCH` tells whether the Buildroot patch to fix libtool cross-compilation issues should be applied or not. Valid values are `YES` and `NO`. By default, the value is `YES`
- `LIBFOO_INSTALL_STAGING_OPTS` contains the make options used to install the package to the staging directory. By default, the value is `DESTDIR=$(STAGING_DIR) install`, which is correct for most autotools packages. It is still possible to override it.
- `LIBFOO_INSTALL_TARGET_OPTS` contains the make options used to install the package to the target directory. By default, the value is `DESTDIR=$(TARGET_DIR) install`. The default value is correct for most autotools packages, but it is still possible to override it if needed.

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:

- By adding a post-operation hook (after extract, patch, configure, build or install). See Section 17.14, “Hooks available in the various build steps” for details.
- By overriding one of the steps. For example, even if the autotools infrastructure is used, if the package `.mk` file defines its own `LIBFOO_CONFIGURE_CMDS` 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.

## 17.7. Infrastructure for CMake-based packages

### 17.7.1. `cmake-package` tutorial

First, let’s see how to write a `.mk` file for a CMake-based package, with an example :

    01: ################################################################################
    02: #
    03: # libfoo
    04: #
    05: ################################################################################
    06:
    07: LIBFOO_VERSION = 1.0
    08: LIBFOO_SOURCE = libfoo-$(LIBFOO_VERSION).tar.gz
    09: LIBFOO_SITE = http://www.foosoftware.org/download
    10: LIBFOO_INSTALL_STAGING = YES
    11: LIBFOO_INSTALL_TARGET = NO
    12: LIBFOO_CONF_OPTS = -DBUILD_DEMOS=ON
    13: LIBFOO_DEPENDENCIES = libglib2 host-pkgconf
    14:
    15: $(eval $(cmake-package))

On line 7, we declare the version of the package.

On line 8 and 9, we declare the name of the tarball (xz-ed tarball recommended) and the location of the tarball on the Web. Buildroot will automatically download the tarball from this location.

On line 10, we tell Buildroot to install the package to the staging directory. The staging directory, located in `output/staging/` 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 `make install` command.

On line 11, we tell Buildroot to not install the package to the target directory. This directory contains what will become the root filesystem running on the target. For purely static libraries, it is not necessary to install them in the target directory because they will not be used at runtime. By default, target installation is enabled; setting this variable to NO is almost never needed. Also by default, packages are installed in this location using the `make install` command.

On line 12, we tell Buildroot to pass custom options to CMake when it is configuring the package.

On line 13, we declare our dependencies, so that they are built before the build process of our package starts.

Finally, on line line 15, we invoke the `cmake-package` macro that generates all the Makefile rules that actually allows the package to be built.

### 17.7.2. `cmake-package` reference

The main macro of the CMake package infrastructure is `cmake-package`. It is similar to the `generic-package` macro. The ability to have target and host packages is also available, with the `host-cmake-package` macro.

Just like the generic infrastructure, the CMake infrastructure works by defining a number of variables before calling the `cmake-package` macro.

First, all the package metadata information variables that exist in the generic infrastructure also exist in the CMake infrastructure: `LIBFOO_VERSION`, `LIBFOO_SOURCE`, `LIBFOO_PATCH`, `LIBFOO_SITE`, `LIBFOO_SUBDIR`, `LIBFOO_DEPENDENCIES`, `LIBFOO_INSTALL_STAGING`, `LIBFOO_INSTALL_TARGET`.

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.

- `LIBFOO_SUBDIR` 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 `HOST_LIBFOO_SUBDIR` is not specified, it defaults to `LIBFOO_SUBDIR`.
- `LIBFOO_CONF_ENV`, to specify additional environment variables to pass to CMake. By default, empty.

- `LIBFOO_CONF_OPTS`, to specify additional configure options to pass to CMake. By default, empty. A number of common CMake options are set by the `cmake-package` infrastructure; so it is normally not necessary to set them in the package’s `*.mk` file unless you want to override them:

  - `CMAKE_BUILD_TYPE` is driven by `BR2_ENABLE_DEBUG`;
  - `CMAKE_INSTALL_PREFIX`;
  - `BUILD_SHARED_LIBS` is driven by `BR2_PREFER_STATIC_LIBS`;
  - `BUILD_DOC`, `BUILD_DOCS` are disabled;
  - `BUILD_EXAMPLE`, `BUILD_EXAMPLES` are disabled;
  - `BUILD_TEST`, `BUILD_TESTS`, `BUILD_TESTING` are disabled.
- `LIBFOO_MAKE`, to specify an alternate `make` command. This is typically useful when parallel make is enabled in the configuration (using `BR2_JLEVEL`) but that this feature should be disabled for the given package, for one reason or another. By default, set to `$(MAKE)`. If parallel building is not supported by the package, then it should be set to `LIBFOO_MAKE=$(MAKE1)`.
- `LIBFOO_MAKE_ENV`, to specify additional environment variables to pass to make in the build step. These are passed before the `make` command. By default, empty.
- `LIBFOO_MAKE_OPTS`, to specify additional variables to pass to make in the build step. These are passed after the `make` command. By default, empty.
- `LIBFOO_INSTALL_STAGING_OPTS` contains the make options used to install the package to the staging directory. By default, the value is `DESTDIR=$(STAGING_DIR) install`, which is correct for most CMake packages. It is still possible to override it.
- `LIBFOO_INSTALL_TARGET_OPTS` contains the make options used to install the package to the target directory. By default, the value is `DESTDIR=$(TARGET_DIR) install`. The default value is correct for most CMake packages, but it is still possible to override it if needed.

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:

- By adding a post-operation hook (after extract, patch, configure, build or install). See Section 17.14, “Hooks available in the various build steps” for details.
- By overriding one of the steps. For example, even if the CMake infrastructure is used, if the package `.mk` file defines its own `LIBFOO_CONFIGURE_CMDS` 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.

## 17.8. Infrastructure for Python packages

This infrastructure applies to Python packages that use the standard Python setuptools mechanism as their build system, generally recognizable by the usage of a `setup.py` script.

### 17.8.1. `python-package` tutorial

First, let’s see how to write a `.mk` file for a Python package, with an example :

    01: ################################################################################
    02: #
    03: # python-foo
    04: #
    05: ################################################################################
    06:
    07: PYTHON_FOO_VERSION = 1.0
    08: PYTHON_FOO_SOURCE = python-foo-$(PYTHON_FOO_VERSION).tar.xz
    09: PYTHON_FOO_SITE = http://www.foosoftware.org/download
    10: PYTHON_FOO_LICENSE = BSD-3c
    11: PYTHON_FOO_LICENSE_FILES = LICENSE
    12: PYTHON_FOO_ENV = SOME_VAR=1
    13: PYTHON_FOO_DEPENDENCIES = libmad
    14: PYTHON_FOO_SETUP_TYPE = distutils
    15:
    16: $(eval $(python-package))

On line 7, we declare the version of the package.

On line 8 and 9, we declare the name of the tarball (xz-ed tarball recommended) and the location of the tarball on the Web. Buildroot will automatically download the tarball from this location.

On line 10 and 11, we give licensing details about the package (its license on line 10, and the file containing the license text on line 11).

On line 12, we tell Buildroot to pass custom options to the Python `setup.py` script when it is configuring the package.

On line 13, we declare our dependencies, so that they are built before the build process of our package starts.

On line 14, we declare the specific Python build system being used. In this case the `distutils` Python build system is used. The two supported ones are `distutils` and `setuptools`.

Finally, on line 16, we invoke the `python-package` macro that generates all the Makefile rules that actually allow the package to be built.

### 17.8.2. `python-package` reference

As a policy, packages that merely provide Python modules should all be named `python-<something>` in Buildroot. Other packages that use the Python build system, but are not Python modules, can freely choose their name (existing examples in Buildroot are `scons` and `supervisor`).

In their `Config.in` file, they should depend on `BR2_PACKAGE_PYTHON` so that when Buildroot will enable Python 3 usage for modules, we will be able to enable Python modules progressively on Python 3.

The main macro of the Python package infrastructure is `python-package`. It is similar to the `generic-package` macro. It is also possible to create Python host packages with the `host-python-package` macro.

Just like the generic infrastructure, the Python infrastructure works by defining a number of variables before calling the `python-package` or `host-python-package` macros.

All the package metadata information variables that exist in the generic package infrastructure Section 17.5.2, “`generic-package` reference” also exist in the Python infrastructure: `PYTHON_FOO_VERSION`, `PYTHON_FOO_SOURCE`, `PYTHON_FOO_PATCH`, `PYTHON_FOO_SITE`, `PYTHON_FOO_SUBDIR`, `PYTHON_FOO_DEPENDENCIES`, `PYTHON_FOO_LICENSE`, `PYTHON_FOO_LICENSE_FILES`, `PYTHON_FOO_INSTALL_STAGING`, etc.

Note that:

- It is not necessary to add `python` or `host-python` in the `PYTHON_FOO_DEPENDENCIES` variable of a package, since these basic dependencies are automatically added as needed by the Python package infrastructure.
- Similarly, it is not needed to add `host-setuptools` and/or `host-distutilscross` dependencies to `PYTHON_FOO_DEPENDENCIES` for setuptools-based packages, since these are automatically added by the Python infrastructure as needed.

One variable specific to the Python infrastructure is mandatory:

- `PYTHON_FOO_SETUP_TYPE`, to define which Python build system is used by the package. The two supported values are `distutils` and `setuptools`. If you don’t know which one is used in your package, look at the `setup.py` file in your package source code, and see whether it imports things from the `distutils` module or the `setuptools` module.

A few additional variables, specific to the Python infrastructure, can optionally be defined, depending on the package’s needs. Many of them are only useful in very specific cases, typical packages will therefore only use a few of them, or none.

- `PYTHON_FOO_ENV`, to specify additional environment variables to pass to the Python `setup.py` script (for both the build and install steps). Note that the infrastructure is automatically passing several standard variables, defined in `PKG_PYTHON_DISTUTILS_ENV` (for distutils target packages), `HOST_PKG_PYTHON_DISTUTILS_ENV` (for distutils host packages), `PKG_PYTHON_SETUPTOOLS_ENV` (for setuptools target packages) and `HOST_PKG_PYTHON_SETUPTOOLS_ENV` (for setuptools host packages).
- `PYTHON_FOO_BUILD_OPTS`, to specify additional options to pass to the Python `setup.py` script during the build step. For target distutils packages, the `PKG_PYTHON_DISTUTILS_BUILD_OPTS` options are already passed automatically by the infrastructure.
- `PYTHON_FOO_INSTALL_TARGET_OPTS`, `PYTHON_FOO_INSTALL_STAGING_OPTS`, `HOST_PYTHON_FOO_INSTALL_OPTS` to specify additional options to pass to the Python `setup.py` script during the target installation step, the staging installation step or the host installation, respectively. Note that the infrastructure is automatically passing some options, defined in `PKG_PYTHON_DISTUTILS_INSTALL_TARGET_OPTS` or `PKG_PYTHON_DISTUTILS_INSTALL_STAGING_OPTS` (for target distutils packages), `HOST_PKG_PYTHON_DISTUTILS_INSTALL_OPTS` (for host distutils packages), `PKG_PYTHON_SETUPTOOLS_INSTALL_TARGET_OPTS` or `PKG_PYTHON_SETUPTOOLS_INSTALL_STAGING_OPTS` (for target setuptools packages) and `HOST_PKG_PYTHON_SETUPTOOLS_INSTALL_OPTS` (for host setuptools packages).
- `HOST_PYTHON_FOO_NEEDS_HOST_PYTHON`, to define the host python interpreter. The usage of this variable is limited to host packages. The two supported value are `python2` and `python3`. It will ensures the right host python package is available and will invoke it for the build. If some build steps are overloaded, the right python interpreter must be explicitly called in the commands.

With the Python infrastructure, all the steps required to build and install the packages are already defined, and they generally work well for most Python-based packages. However, when required, it is still possible to customize what is done in any particular step:

- By adding a post-operation hook (after extract, patch, configure, build or install). See Section 17.14, “Hooks available in the various build steps” for details.
- By overriding one of the steps. For example, even if the Python infrastructure is used, if the package `.mk` file defines its own `PYTHON_FOO_BUILD_CMDS` variable, it will be used instead of the default Python one. However, using this method should be restricted to very specific cases. Do not use it in the general case.

## 17.9. Infrastructure for LuaRocks-based packages

### 17.9.1. `luarocks-package` tutorial

First, let’s see how to write a `.mk` file for a LuaRocks-based package, with an example :

    01: ################################################################################
    02: #
    03: # luafoo
    04: #
    05: ################################################################################
    06:
    07: LUAFOO_VERSION = 1.0.2-1
    08: LUAFOO_DEPENDENCIES = foo
    09:
    10: LUAFOO_BUILD_OPTS += FOO_INCDIR=$(STAGING_DIR)/usr/include
    11: LUAFOO_BUILD_OPTS += FOO_LIBDIR=$(STAGING_DIR)/usr/lib
    12: LUAFOO_LICENSE = luaFoo license
    13: LUAFOO_LICENSE_FILES = COPYING
    14:
    15: $(eval $(luarocks-package))

On line 7, we declare the version of the package (the same as in the rockspec, which is the concatenation of the upstream version and the rockspec revision, separated by a hyphen -).

On line 8, we declare our dependencies against native libraries, so that they are built before the build process of our package starts.

On lines 10-11, we tell Buildroot to pass custom options to LuaRocks when it is building the package.

On lines 12-13, we specify the licensing terms for the package.

Finally, on line 15, we invoke the `luarocks-package` macro that generates all the Makefile rules that actually allows the package to be built.

### 17.9.2. `luarocks-package` reference

LuaRocks is a deployment and management system for Lua modules, and supports various `build.type`: `builtin`, `make` and `cmake`. In the context of Buildroot, the `luarocks-package` infrastructure only supports the `builtin` mode. LuaRocks packages that use the `make` or `cmake` build mechanisms should instead be packaged using the `generic-package` and `cmake-package` infrastructures in Buildroot, respectively.

The main macro of the LuaRocks package infrastructure is `luarocks-package`: like `generic-package` it works by defining a number of variables providing metadata information about the package, and then calling `luarocks-package`. It is worth mentioning that building LuaRocks packages for the host is not supported, so the macro `host-luarocks-package` is not implemented.

Just like the generic infrastructure, the LuaRocks infrastructure works by defining a number of variables before calling the `luarocks-package` macro.

First, all the package metadata information variables that exist in the generic infrastructure also exist in the LuaRocks infrastructure: `LUAFOO_VERSION`, `LUAFOO_SOURCE`, `LUAFOO_SITE`, `LUAFOO_DEPENDENCIES`, `LUAFOO_LICENSE`, `LUAFOO_LICENSE_FILES`.

Two of them are populated by the LuaRocks infrastructure (for the `download` step). If your package is not hosted on the LuaRocks mirror `$(BR2_LUAROCKS_MIRROR)`, you can override them:

- `LUAFOO_SITE`, which defaults to `$(BR2_LUAROCKS_MIRROR)`
- `LUAFOO_SOURCE`, which defaults to `luafoo-$(LUAFOO_VERSION).src.rock`

A few additional variables, specific to the LuaRocks infrastructure, are also defined. They can be overridden in specific cases.

- `LUAFOO_ROCKSPEC`, which defaults to `luafoo-$(LUAFOO_VERSION).rockspec`
- `LUAFOO_SUBDIR`, which defaults to `luafoo-$(LUAFOO_VERSION_WITHOUT_ROCKSPEC_REVISION)`
- `LUAFOO_BUILD_OPTS` contains additional build options for the `luarocks build` call.

## 17.10. Infrastructure for Perl/CPAN packages

### 17.10.1. `perl-package` tutorial

First, let’s see how to write a `.mk` file for a Perl/CPAN package, with an example :

    01: ################################################################################
    02: #
    03: # perl-foo-bar
    04: #
    05: ################################################################################
    06:
    07: PERL_FOO_BAR_VERSION = 0.02
    08: PERL_FOO_BAR_SOURCE = Foo-Bar-$(PERL_FOO_BAR_VERSION).tar.gz
    09: PERL_FOO_BAR_SITE = $(BR2_CPAN_MIRROR)/authors/id/M/MO/MONGER
    10: PERL_FOO_BAR_DEPENDENCIES = perl-strictures
    11: PERL_FOO_BAR_LICENSE = Artistic or GPLv1+
    12: PERL_FOO_BAR_LICENSE_FILES = LICENSE
    13:
    14: $(eval $(perl-package))

On line 7, we declare the version of the package.

On line 8 and 9, we declare the name of the tarball and the location of the tarball on a CPAN server. Buildroot will automatically download the tarball from this location.

On line 10, we declare our dependencies, so that they are built before the build process of our package starts.

On line 11 and 12, we give licensing details about the package (its license on line 11, and the file containing the license text on line 12).

Finally, on line 14, we invoke the `perl-package` macro that generates all the Makefile rules that actually allow the package to be built.

Most of these data can be retrieved from https://metacpan.org/. So, this file and the Config.in can be generated by running the script `supports/scripts/scancpan Foo-Bar` in the Buildroot directory (or in the `BR2_EXTERNAL` directory). This script creates a Config.in file and foo-bar.mk file for the requested package, and also recursively for all dependencies specified by CPAN. You should still manually edit the result. In particular, the following things should be checked.

- If the perl module links with a shared library that is provided by another (non-perl) package, this dependency is not added automatically. It has to be added manually to `PERL_FOO_BAR_DEPENDENCIES`.
- The `package/Config.in` file has to be updated manually to include the generated Config.in files. As a hint, the `scancpan` script prints out the required `source "…"` statements, sorted alphabetically.

### 17.10.2. `perl-package` reference

As a policy, packages that provide Perl/CPAN modules should all be named `perl-<something>` in Buildroot.

This infrastructure handles various Perl build systems : `ExtUtils-MakeMaker`, `Module-Build` and `Module-Build-Tiny`. `Build.PL` is always preferred when a package provides a `Makefile.PL` and a `Build.PL`.

The main macro of the Perl/CPAN package infrastructure is `perl-package`. It is similar to the `generic-package` macro. The ability to have target and host packages is also available, with the `host-perl-package` macro.

Just like the generic infrastructure, the Perl/CPAN infrastructure works by defining a number of variables before calling the `perl-package` macro.

First, all the package metadata information variables that exist in the generic infrastructure also exist in the Perl/CPAN infrastructure: `PERL_FOO_VERSION`, `PERL_FOO_SOURCE`, `PERL_FOO_PATCH`, `PERL_FOO_SITE`, `PERL_FOO_SUBDIR`, `PERL_FOO_DEPENDENCIES`, `PERL_FOO_INSTALL_TARGET`.

Note that setting `PERL_FOO_INSTALL_STAGING` to `YES` has no effect unless a `PERL_FOO_INSTALL_STAGING_CMDS` variable is defined. The perl infrastructure doesn’t define these commands since Perl modules generally don’t need to be installed to the `staging` directory.

A few additional variables, specific to the Perl/CPAN 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.

- `PERL_FOO_CONF_ENV`/`HOST_PERL_FOO_CONF_ENV`, to specify additional environment variables to pass to the `perl Makefile.PL` or `perl Build.PL`. By default, empty.
- `PERL_FOO_CONF_OPTS`/`HOST_PERL_FOO_CONF_OPTS`, to specify additional configure options to pass to the `perl Makefile.PL` or `perl Build.PL`. By default, empty.
- `PERL_FOO_BUILD_OPTS`/`HOST_PERL_FOO_BUILD_OPTS`, to specify additional options to pass to `make pure_all` or `perl Build build` in the build step. By default, empty.
- `PERL_FOO_INSTALL_TARGET_OPTS`, to specify additional options to pass to `make pure_install` or `perl Build install` in the install step. By default, empty.
- `HOST_PERL_FOO_INSTALL_OPTS`, to specify additional options to pass to `make pure_install` or `perl Build install` in the install step. By default, empty.

## 17.11. Infrastructure for virtual packages

In Buildroot, a virtual package is a package whose functionalities are provided by one or more packages, referred to as providers. The virtual package management is an extensible mechanism allowing the user to choose the provider used in the rootfs.

For example, OpenGL ES is an API for 2D and 3D graphics on embedded systems. The implementation of this API is different for the Allwinner Tech Sunxi and the Texas Instruments OMAP35xx platforms. So `libgles` will be a virtual package and `sunxi-mali` and `ti-gfx` will be the providers.

### 17.11.1. `virtual-package` tutorial

In the following example, we will explain how to add a new virtual package (something-virtual) and a provider for it (some-provider).

First, let’s create the virtual package.

### 17.11.2. Virtual package’s `Config.in` file

The `Config.in` file of virtual package something-virtual should contain:

    01: config BR2_PACKAGE_HAS_SOMETHING_VIRTUAL
    02:     bool
    03:
    04: config BR2_PACKAGE_PROVIDES_SOMETHING_VIRTUAL
    05:     depends on BR2_PACKAGE_HAS_SOMETHING_VIRTUAL
    06:     string

In this file, we declare two options, `BR2_PACKAGE_HAS_SOMETHING_VIRTUAL` and `BR2_PACKAGE_PROVIDES_SOMETHING_VIRTUAL`, whose values will be used by the providers.

### 17.11.3. Virtual package’s `.mk` file

The `.mk` for the virtual package should just evaluate the `virtual-package` macro:

    01: ################################################################################
    02: #
    03: # something-virtual
    04: #
    05: ################################################################################
    06:
    07: $(eval $(virtual-package))

The ability to have target and host packages is also available, with the `host-virtual-package` macro.

### 17.11.4. Provider’s `Config.in` file

When adding a package as a provider, only the `Config.in` file requires some modifications.

The `Config.in` file of the package some-provider, which provides the functionalities of something-virtual, should contain:

    01: config BR2_PACKAGE_SOME_PROVIDER
    02:     bool "some-provider"
    03:     select BR2_PACKAGE_HAS_SOMETHING_VIRTUAL
    04:     help
    05:       This is a comment that explains what some-provider is.
    06:
    07:       http://foosoftware.org/some-provider/
    08:
    09: if BR2_PACKAGE_SOME_PROVIDER
    10: config BR2_PACKAGE_PROVIDES_SOMETHING_VIRTUAL
    11:     default "some-provider"
    12: endif

On line 3, we select `BR2_PACKAGE_HAS_SOMETHING_VIRTUAL`, and on line 11, we set the value of `BR2_PACKAGE_PROVIDES_SOMETHING_VIRTUAL` to the name of the provider, but only if it is selected.

See Chapter 25, List of virtual packages for the symbols to select if you implement a new provider for an existing virtual package.

### 17.11.5. Provider’s `.mk` file

The `.mk` file should also declare an additional variable `SOME_PROVIDER_PROVIDES` to contain the names of all the virtual packages it is an implementation of:

    01: SOME_PROVIDER_PROVIDES = something-virtual

Of course, do not forget to add the proper build and runtime dependencies for this package!

See Chapter 25, List of virtual packages for the names of virtual packages to provide if you implement a new provider for an existing virtual package.

### 17.11.6. Notes on depending on a virtual package

When adding a package that requires a certain `FEATURE` provided by a virtual package, you have to use `depends on BR2_PACKAGE_HAS_FEATURE`, like so:

    config BR2_PACKAGE_HAS_FEATURE
        bool

    config BR2_PACKAGE_FOO
        bool "foo"
        depends on BR2_PACKAGE_HAS_FEATURE

### 17.11.7. Notes on depending on a specific provider

If your package really requires a specific provider, then you’ll have to make your package `depends on` this provider; you can not `select` a provider.

Let’s take an example with two providers for a `FEATURE`:

    config BR2_PACKAGE_HAS_FEATURE
        bool

    config BR2_PACKAGE_FOO
        bool "foo"
        select BR2_PACKAGE_HAS_FEATURE

    config BR2_PACKAGE_BAR
        bool "bar"
        select BR2_PACKAGE_HAS_FEATURE

And you are adding a package that needs `FEATURE` as provided by `foo`, but not as provided by `bar`.

If you were to use `select BR2_PACKAGE_FOO`, then the user would still be able to select `BR2_PACKAGE_BAR` in the menuconfig. This would create a configuration inconsistency, whereby two providers of the same `FEATURE` would be enabled at once, one explicitly set by the user, the other implicitly by your `select`.

Instead, you have to use `depends on BR2_PACKAGE_FOO`, which avoids any implicit configuration inconsistency.

## 17.12. Infrastructure for packages using kconfig for configuration files

A popular way for a software package to handle user-specified configuration is `kconfig`. Among others, it is used by the Linux kernel, Busybox, and Buildroot itself. The presence of a .config file and a `menuconfig` target are two well-known symptoms of kconfig being used.

Buildroot features an infrastructure for packages that use kconfig for their configuration. This infrastructure provides the necessary logic to expose the package’s `menuconfig` target as `foo-menuconfig` in Buildroot, and to handle the copying back and forth of the configuration file in a correct way.

The `kconfig-package` infrastructure is based on the `generic-package` infrastructure. All variables supported by `generic-package` are available in `kconfig-package` as well. See Section 17.5.2, “`generic-package` reference” for more details.

In order to use the `kconfig-package` infrastructure for a Buildroot package, the minimally required lines in the `.mk` file, in addition to the variables required by the `generic-package` infrastructure, are:

    FOO_KCONFIG_FILE = reference-to-source-configuration-file

    $(eval $(kconfig-package))

This snippet creates the following make targets:

- `foo-menuconfig`, which calls the package’s `menuconfig` target
- `foo-update-config`, which copies the configuration back to the source configuration file.

and ensures that the source configuration file is copied to the build directory at the right moment.

In addition to these minimally required lines, several optional variables can be set to suit the needs of the package under consideration:

- `FOO_KCONFIG_EDITORS`: a space-separated list of kconfig editors to support, for example menuconfig xconfig. By default, menuconfig.
- `FOO_KCONFIG_OPTS`: extra options to pass when calling the kconfig editors. This may need to include $(FOO_MAKE_OPTS), for example. By default, empty.
- `FOO_KCONFIG_FIXUP_CMDS`: a list of shell commands needed to fixup the configuration file after copying it or running a kconfig editor. Such commands may be needed to ensure a configuration consistent with other configuration of Buildroot, for example. By default, empty.

## 17.13. Infrastructure for asciidoc documents

The Buildroot manual, which you are currently reading, is entirely written using the AsciiDoc mark-up syntax. The manual is then rendered to many formats:

- html
- split-html
- pdf
- epub
- text

Although Buildroot only contains one document written in AsciiDoc, there is, as for packages, an infrastructure for rendering documents using the AsciiDoc syntax.

Also as for packages, the AsciiDoc infrastructure is available from BR2_EXTERNAL Section 9.2, “Keeping customizations outside of Buildroot”. This allows documentation for a BR2_EXTERNAL tree to match the Buildroot documentation, as it will be rendered to the same formats and use the same layout and theme.

### 17.13.1. `asciidoc-document` tutorial

Whereas package infrastructures are suffixed with `-package`, the document infrastructures are suffixed with `-document`. So, the AsciiDoc infrastructure is named `asciidoc-document`.

Here is an example to render a simple AsciiDoc document.

    01: ################################################################################
    02: #
    03: # foo-document
    04: #
    05: ################################################################################
    06:
    07: FOO_SOURCES = $(sort $(wildcard $(pkgdir)/*))
    08: $(eval $(call asciidoc-document))

On line 7, the Makefile declares what the sources of the document are. Currently, it is expected that the document’s sources are only local; Buildroot will not attempt to download anything to render a document. Thus, you must indicate where the sources are. Usually, the string above is sufficient for a document with no sub-directory structure.

On line 8, we call the `asciidoc-document` function, which generates all the Makefile code necessary to render the document.

### 17.13.2. `asciidoc-document` reference

The list of variables that can be set in a `.mk` file to give metadata information is (assuming the document name is `foo`) :

- `FOO_SOURCES`, mandatory, defines the source files for the document.
- `FOO_RESOURCES`, optional, may contain a space-separated list of paths to one or more directories containing so-called resources (like CSS or images). By default, empty.

There are also additional hooks (see Section 17.14, “Hooks available in the various build steps” for general information on hooks), that a document may set to define extra actions to be done at various steps:

- `FOO_POST_RSYNC_HOOKS` to run additional commands after the sources have been copied by Buildroot. This can for example be used to generate part of the manual with information extracted from the tree. As an example, Buildroot uses this hook to generate the tables in the appendices.
- `FOO_CHECK_DEPENDENCIES_HOOKS` to run additional tests on required components to generate the document. In AsciiDoc, it is possible to call filters, that is, programs that will parse an AsciiDoc block and render it appropriately (e.g. ditaa or aafigure).
- `FOO_CHECK_DEPENDENCIES_<FMT>_HOOKS`, to run additional tests for the specified format `<FMT>` (see the list of rendered formats, above).

Here is a complete example that uses all variables and all hooks:

    01: ################################################################################
    02: #
    03: # foo-document
    04: #
    05: ################################################################################
    06:
    07: FOO_SOURCES = $(sort $(wildcard $(pkgdir)/*))
    08: FOO_RESOURCES = $(sort $(wildcard $(pkgdir)/ressources))
    09:
    10: define FOO_GEN_EXTRA_DOC
    11:     /path/to/generate-script --outdir=$(@D)
    12: endef
    13: FOO_POST_RSYNC_HOOKS += FOO_GEN_EXTRA_DOC
    14:
    15: define FOO_CHECK_MY_PROG
    16:     if ! which my-prog >/dev/null 2>&1; then \
    17:         echo "You need my-prog to generate the foo document"; \
    18:         exit 1; \
    19:     fi
    20: endef
    21: FOO_CHECK_DEPENDENCIES_HOOKS += FOO_CHECK_MY_PROG
    22:
    23: define FOO_CHECK_MY_OTHER_PROG
    24:     if ! which my-other-prog >/dev/null 2>&1; then \
    25:         echo "You need my-other-prog to generate the foo document as PDF"; \
    26:         exit 1; \
    27:     fi
    28: endef
    29: FOO_CHECK_DEPENDENCIES_PDF_HOOKS += FOO_CHECK_MY_OTHER_PROG
    30:
    31: $(eval $(call asciidoc-document))

## 17.14. Hooks available in the various build steps

The generic infrastructure (and as a result also the derived autotools and cmake infrastructures) allow packages to specify hooks. These define further actions to perform after existing steps. Most hooks aren’t really useful for generic packages, since the `.mk` file already has full control over the actions performed in each step of the package construction.

The following hook points are available:

- `LIBFOO_PRE_DOWNLOAD_HOOKS`
- `LIBFOO_POST_DOWNLOAD_HOOKS`
- `LIBFOO_PRE_EXTRACT_HOOKS`
- `LIBFOO_POST_EXTRACT_HOOKS`
- `LIBFOO_PRE_RSYNC_HOOKS`
- `LIBFOO_POST_RSYNC_HOOKS`
- `LIBFOO_PRE_PATCH_HOOKS`
- `LIBFOO_POST_PATCH_HOOKS`
- `LIBFOO_PRE_CONFIGURE_HOOKS`
- `LIBFOO_POST_CONFIGURE_HOOKS`
- `LIBFOO_PRE_BUILD_HOOKS`
- `LIBFOO_POST_BUILD_HOOKS`
- `LIBFOO_PRE_INSTALL_HOOKS` (for host packages only)
- `LIBFOO_POST_INSTALL_HOOKS` (for host packages only)
- `LIBFOO_PRE_INSTALL_STAGING_HOOKS` (for target packages only)
- `LIBFOO_POST_INSTALL_STAGING_HOOKS` (for target packages only)
- `LIBFOO_PRE_INSTALL_TARGET_HOOKS` (for target packages only)
- `LIBFOO_POST_INSTALL_TARGET_HOOKS` (for target packages only)
- `LIBFOO_PRE_INSTALL_IMAGES_HOOKS`
- `LIBFOO_POST_INSTALL_IMAGES_HOOKS`
- `LIBFOO_PRE_LEGAL_INFO_HOOKS`
- `LIBFOO_POST_LEGAL_INFO_HOOKS`

These variables are lists 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:

    define LIBFOO_POST_PATCH_FIXUP
            action1
            action2
    endef

    LIBFOO_POST_PATCH_HOOKS += LIBFOO_POST_PATCH_FIXUP

### 17.14.1. Using the `POST_RSYNC` hook

The `POST_RSYNC` hook is run only for packages that use a local source, either through the `local` site method or the `OVERRIDE_SRCDIR` mechanism. In this case, package sources are copied using `rsync` from the local location into the buildroot build directory. The `rsync` command does not copy all files from the source directory, though. Files belonging to a version control system, like the directories `.git`, `.hg`, etc. are not copied. For most packages this is sufficient, but a given package can perform additional actions using the `POST_RSYNC` hook.

In principle, the hook can contain any command you want. One specific use case, though, is the intentional copying of the version control directory using `rsync`. The `rsync` command you use in the hook can, among others, use the following variables:

- `$(SRCDIR)`: the path to the overridden source directory
- `$(@D)`: the path to the build directory

## 17.15. Gettext integration and interaction with packages

Many packages that support internationalization use the gettext library. Dependencies for this library are fairly complicated and therefore, deserve some explanation.

The uClibc C library doesn’t implement gettext functionality; therefore with this C library, a separate gettext must be compiled, which is provided by the additional `libintl` library, part of the `gettext` package.

On the other hand, the glibc C library does integrate its own gettext library functions, so it is not necessary to build a separate `libintl` library.

However, certain packages need some gettext utilities on the target, such as the `gettext` program itself, which allows to retrieve translated strings, from the command line.

Additionally, some packages (such as `libglib2`) do require gettext functions unconditionally, while other packages (in general, those who support `--disable-nls`) only require gettext functions when locale support is enabled.

Therefore, Buildroot defines two configuration options:

- `BR2_NEEDS_GETTEXT`, which is true as soon as the toolchain doesn’t provide its own gettext implementation
- `BR2_NEEDS_GETTEXT_IF_LOCALE`, which is true if the toolchain doesn’t provide its own gettext implementation and if locale support is enabled

Packages that need gettext only when locale support is enabled should:

- use `select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT_IF_LOCALE` in the `Config.in` file;
- use `$(if $(BR2_NEEDS_GETTEXT_IF_LOCALE),gettext)` in the package `DEPENDENCIES` variable in the `.mk` file.

Packages that unconditionally need gettext (which should be very rare) should:

- use `select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT` in the `Config.in` file;
- use `$(if $(BR2_NEEDS_GETTEXT),gettext)` in the package `DEPENDENCIES` variable in the `.mk` file.

Packages that need the `gettext` utilities on the target (should be rare) should:

- use `select BR2_PACKAGE_GETTEXT` in their `Config.in` file, indicating in a comment above that it’s a runtime dependency only.
- not add any `gettext` dependency in the `DEPENDENCIES` variable of their `.mk` file.

## 17.16. Tips and tricks

### 17.16.1. Package name, config entry name and makefile variable relationship

In Buildroot, there is some relationship between:

- the package name, which is the package directory name (and the name of the `*.mk` file);
- the config entry name that is declared in the `Config.in` file;
- the makefile variable prefix.

It is mandatory to maintain consistency between these elements, using the following rules:

- the package directory and the `*.mk` name are the package name itself (e.g.: `package/foo-bar_boo/foo-bar_boo.mk`);
- the make target name is the package name itself (e.g.: `foo-bar_boo`);
- the config entry is the upper case package name with `.` and `-` characters substituted with `_`, prefixed with `BR2_PACKAGE_` (e.g.: `BR2_PACKAGE_FOO_BAR_BOO`);
- the `*.mk` file variable prefix is the upper case package name with `.` and `-` characters substituted with `_` (e.g.: `FOO_BAR_BOO_VERSION`).

### 17.16.2. How to add a package from GitHub

Packages on GitHub often don’t have a download area with release tarballs. However, it is possible to download tarballs directly from the repository on GitHub. As GitHub is known to have changed download mechanisms in the past, the github helper function should be used as shown below.

    FOO_VERSION = v1.0 # tag or full commit ID
    FOO_SITE = $(call github,<user>,<package>,$(FOO_VERSION))

Notes

- The FOO_VERSION can either be a tag or a commit ID.
- The tarball name generated by github matches the default one from Buildroot (e.g.: `foo-f6fb6654af62045239caed5950bc6c7971965e60.tar.gz`), so it is not necessary to specify it in the `.mk` file.
- When using a commit ID as version, you should use the full 40 hex characters.

If the package you wish to add does have a release section on GitHub, the maintainer may have uploaded a release tarball, or the release may just point to the automatically generated tarball from the git tag. If there is a release tarball uploaded by the maintainer, we prefer to use that since it may be slightly different (e.g. it contains a configure script so we don’t need to do AUTORECONF).

You can see on the release page if it’s an uploaded tarball or a git tag:

- If there is a green download button, like mongrel2, then it was uploaded by the maintainer and you should use the link of that button to specify `FOO_SITE`, and not use the github helper.
- If there is grey download button, like xbmc, then it’s an automatically generated tarball and you should use the github helper function.

## 17.17. Conclusion

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.

If you package software that might be useful for other people, don’t forget to send a patch to the Buildroot mailing list (see Section 21.5, “Submitting patches”)!

## Chapter 18. Patching a package

While integrating a new package or updating an existing one, it may be necessary to patch the source of the software to get it cross-built within Buildroot.

Buildroot offers an infrastructure to automatically handle this during the builds. It supports three ways of applying patch sets: downloaded patches, patches supplied within buildroot and patches located in a user-defined global patch directory.

## 18.1. Providing patches

### 18.1.1. Downloaded

If it is necessary to apply a patch that is available for download, then add it to the `<packagename>_PATCH` variable. It is downloaded from the same site as the package itself. It can be a single patch, or a tarball containing a patch series.

This method is typically used for packages from Debian.

### 18.1.2. Within Buildroot

Most patches are provided within Buildroot, in the package directory; these typically aim to fix cross-compilation, libc support, or other such issues.

These patch files should be named `<packagename>-<number>-<description>.patch`.

A `series` file, as used by `quilt`, may also be added in the package directory. In that case, the `series` file defines the patch application order.

Notes

- The patch files coming with Buildroot should not contain any package version reference in their filename.
- The field `<number>` in the patch file name refers to the apply order.

### 18.1.3. Global patch directory

The `BR2_GLOBAL_PATCH_DIR` configuration file option can be used to specify a space separated list of one or more directories containing global package patches. See Section 9.8, “Adding project-specific patches” for details.

## 18.2. How patches are applied

1. Run the `<packagename>_PRE_PATCH_HOOKS` commands if defined;
2. Cleanup the build directory, removing any existing `*.rej` files;
3. If `<packagename>_PATCH` is defined, then patches from these tarballs are applied;

4. If there are some `*.patch` files in the package’s Buildroot directory or in a package subdirectory named `<packageversion>`, then:

   - If a `series` file exists in the package directory, then patches are applied according to the `series` file;
   - Otherwise, patch files matching `<packagename>-*.patch` are applied in alphabetical order. So, to ensure they are applied in the right order, it is highly recommended to name the patch files like this: `<packagename>-<number>-<description>.patch`, where `<number>` refers to the apply order.
5. If `BR2_GLOBAL_PATCH_DIR` is defined, the directories will be enumerated in the order they are specified. The patches are applied as described in the previous step.
6. Run the `<packagename>_POST_PATCH_HOOKS` commands if defined.

If something goes wrong in the steps 3 or 4, then the build fails.

## 18.3. Format and licensing of the package patches

Patches are released under the same license as the software that is modified.

A message explaining what the patch does, and why it is needed, should be added in the header commentary of the patch.

You should add a `Signed-off-by` statement in the header of the each patch to help with keeping track of the changes and to certify that the patch is released under the same license as the software that is modified.

If the software is under version control, it is recommended to use the upstream SCM software to generate the patch set.

Otherwise, concatenate the header with the output of the `diff -purN package-version.orig/ package-version/` command.

At the end, the patch should look like:

    configure.ac: add C++ support test

    Signed-off-by: John Doe <john.doe@noname.org>

    --- configure.ac.orig
    +++ configure.ac
    @@ -40,2 +40,12 @@

    AC_PROG_MAKE_SET
    +
    +AC_CACHE_CHECK([whether the C++ compiler works],
    +               [rw_cv_prog_cxx_works],
    +               [AC_LANG_PUSH([C++])
    +                AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
    +                               [rw_cv_prog_cxx_works=yes],
    +                               [rw_cv_prog_cxx_works=no])
    +                AC_LANG_POP([C++])])
    +
    +AM_CONDITIONAL([CXX_WORKS], [test "x$rw_cv_prog_cxx_works" = "xyes"])

## 18.4. Integrating patches found on the Web

When integrating a patch of which you are not the author, you have to add a few things in the header of the patch itself.

Depending on whether the patch has been obtained from the project repository itself, or from somewhere on the web, add one of the following tags:

    Backported from: <some commit id>

or

    Fetch from: <some url>

It is also sensible to add a few words about any changes to the patch that may have been necessary.

## Chapter 19. Download infrastructure

TODO

## Chapter 20. Debugging Buildroot

It is possible to instrument the steps `Buildroot` does when building packages. Define the variable `BR2_INSTRUMENTATION_SCRIPTS` to contain the path of one or more scripts (or other executables), in a space-separated list, you want called before and after each step. The scripts are called in sequence, with three parameters:

- `start` or `end` to denote the start (resp. the end) of a step;
- the name of the step about to be started, or which just ended.
- the name of the package

For example :

    make BR2_INSTRUMENTATION_SCRIPTS="/path/to/my/script1 /path/to/my/script2"

That script has access to the following variables:

- `BR2_CONFIG`: the path to the Buildroot .config file
- `HOST_DIR`, `STAGING_DIR`, `TARGET_DIR`: see Section 17.5.2, “`generic-package` reference”
- `BUILD_DIR`: the directory where packages are extracted and built
- `BINARIES_DIR`: the place where all binary files (aka images) are stored
- `BASE_DIR`: the base output directory

## Chapter 21. Contributing to Buildroot

There are many ways in which you can contribute to Buildroot: analyzing and fixing bugs, analyzing and fixing package build failures detected by the autobuilders, testing and reviewing patches sent by other developers, working on the items in our TODO list and sending your own improvements to Buildroot or its manual. The following sections give a little more detail on each of these items.

If you are interested in contributing to Buildroot, the first thing you should do is to subscribe to the Buildroot mailing list. This list is the main way of interacting with other Buildroot developers and to send contributions to. If you aren’t subscribed yet, then refer to Chapter 5, Community resources for the subscription link.

If you are going to touch the code, it is highly recommended to use a git repository of Buildroot, rather than starting from an extracted source code tarball. Git is the easiest way to develop from and directly send your patches to the mailing list. Refer to Chapter 3, Getting Buildroot for more information on obtaining a Buildroot git tree.

## 21.1. Reproducing, analyzing and fixing bugs

A first way of contributing is to have a look at the open bug reports in the Buildroot bug tracker. As we strive to keep the bug count as small as possible, all help in reproducing, analyzing and fixing reported bugs is more than welcome. Don’t hesitate to add a comment to bug reports reporting your findings, even if you don’t yet see the full picture.

## 21.2. Analyzing and fixing autobuild failures

The Buildroot autobuilders are a set of build machines that continuously run Buildroot builds based on random configurations. This is done for all architectures supported by Buildroot, with various toolchains, and with a random selection of packages. With the large commit activity on Buildroot, these autobuilders are a great help in detecting problems very early after commit.

All build results are available at http://autobuild.buildroot.org, statistics are at http://autobuild.buildroot.org/stats.php. Every day, an overview of all failed packages is sent to the mailing list.

Detecting problems is great, but obviously these problems have to be fixed as well. Your contribution is very welcome here! There are basically two things that can be done:

- Analyzing the problems. The daily summary mails do not contain details about the actual failures: in order to see what’s going on you have to open the build log and check the last output. Having someone doing this for all packages in the mail is very useful for other developers, as they can make a quick initial analysis based on this output alone.

- Fixing a problem. When fixing autobuild failures, you should follow these steps:

  1. Check if you can reproduce the problem by building with the same configuration. You can do this manually, or use the br-reproduce-build script that will automatically clone a Buildroot git repository, checkout the correct revision, download and set the right configuration, and start the build.
  2. Analyze the problem and create a fix.
  3. Verify that the problem is really fixed by starting from a clean Buildroot tree and only applying your fix.
  4. Send the fix to the Buildroot mailing list (see Section 21.5, “Submitting patches”). In case you created a patch against the package sources, you should also send the patch upstream so that the problem will be fixed in a later release, and the patch in Buildroot can be removed. In the commit message of a patch fixing an autobuild failure, add a reference to the build result directory, as follows:

    Fixes http://autobuild.buildroot.org/results/51000a9d4656afe9e0ea6f07b9f8ed374c2e4069

## 21.3. Reviewing and testing patches

With the amount of patches sent to the mailing list each day, the maintainer has a very hard job to judge which patches are ready to apply and which ones aren’t. Contributors can greatly help here by reviewing and testing these patches.

In the review process, do not hesitate to respond to patch submissions for remarks, suggestions or anything that will help everyone to understand the patches and make them better. Please use internet style replies in plain text emails when responding to patch submissions.

To indicate approval of a patch, there are three formal tags that keep track of this approval. To add your tag to a patch, reply to it with the approval tag below the original author’s Signed-off-by line. These tags will be picked up automatically by patchwork (see Section 21.3.1, “Applying Patches from Patchwork”) and will be part of the commit log when the patch is accepted.

Tested-by
  Indicates that the patch has been tested successfully. You are encouraged to specify what kind of testing you performed (compile-test on architecture X and Y, runtime test on target A, …). This additional information helps other testers and the maintainer.
Reviewed-by
  Indicates that you code-reviewed the patch and did your best in spotting problems, but you are not sufficiently familiar with the area touched to provide an Acked-by tag. This means that there may be remaining problems in the patch that would be spotted by someone with more experience in that area. Should such problems be detected, your Reviewed-by tag remains appropriate and you cannot be blamed.
Acked-by
  Indicates that you code-reviewed the patch and you are familiar enough with the area touched to feel that the patch can be committed as-is (no additional changes required). In case it later turns out that something is wrong with the patch, your Acked-by could be considered inappropriate. The difference between Acked-by and Reviewed-by is thus mainly that you are prepared to take the blame on Acked patches, but not on Reviewed ones.

If you reviewed a patch and have comments on it, you should simply reply to the patch stating these comments, without providing a Reviewed-by or Acked-by tag. These tags should only be provided if you judge the patch to be good as it is.

It is important to note that neither Reviewed-by nor Acked-by imply that testing has been performed. To indicate that you both reviewed and tested the patch, provide two separate tags (Reviewed/Acked-by and Tested-by).

Note also that any developer can provide Tested/Reviewed/Acked-by tags, without exception, and we encourage everyone to do this. Buildroot does not have a defined group of core developers, it just so happens that some developers are more active than others. The maintainer will value tags according to the track record of their submitter. Tags provided by a regular contributor will naturally be trusted more than tags provided by a newcomer. As you provide tags more regularly, your trustworthiness (in the eyes of the maintainer) will go up, but any tag provided is valuable.

Buildroot’s Patchwork website can be used to pull in patches for testing purposes. Please see Section 21.3.1, “Applying Patches from Patchwork” for more information on using Buildroot’s Patchwork website to apply patches.

### 21.3.1. Applying Patches from Patchwork

The main use of Buildroot’s Patchwork website for a developer is for pulling in patches into their local git repository for testing purposes.

When browsing patches in the patchwork management interface, an `mbox` link is provided at the top of the page. Copy this link address and run the following commands:

    $ git checkout -b <test-branch-name>
    $ wget -O - <mbox-url> | git am

Another option for applying patches is to create a bundle. A bundle is a set of patches that you can group together using the patchwork interface. Once the bundle is created and the bundle is made public, you can copy the `mbox` link for the bundle and apply the bundle using the above commands.

## 21.4. Work on items from the TODO list

If you want to contribute to Buildroot but don’t know where to start, and you don’t like any of the above topics, you can always work on items from the Buildroot TODO list. Don’t hesitate to discuss an item first on the mailing list or on IRC. Do edit the wiki to indicate when you start working on an item, so we avoid duplicate efforts.

## 21.5. Submitting patches

### Note

Please, do not attach patches to bugs, send them to the mailing list instead.

If you made some changes to Buildroot and you would like to contribute them to the Buildroot project, proceed as follows. Starting from the changes committed in your local git view, rebase your development branch on top of the upstream tree before generating a patch set. To do so, run:

    $ git fetch --all --tags
    $ git rebase origin/master

Now, you are ready to generate then submit your patch set.

To generate it, run:

    $ git format-patch -M -n -s -o outgoing origin/master

This will generate patch files in the `outgoing` subdirectory, automatically adding the `Signed-off-by` line.

Once patch files are generated, you can review/edit the commit message before submitting them, using your favorite text editor.

Lastly, send/submit your patch set to the Buildroot mailing list:

    $ git send-email --to buildroot@buildroot.org outgoing/*

Note that `git` should be configured to use your mail account. To configure `git`, see `man git-send-email` or google it.

If you do not use `git send-email`, make sure posted patches are not line-wrapped, otherwise they cannot easily be applied. In such a case, fix your e-mail client, or better yet, learn to use `git send-email`.

### 21.5.1. Cover letter

If you want to present the whole patch set in a separate mail, add `--cover-letter` to the `git format-patch` command (see `man git-format-patch` for further information). This will generate a template for an introduction e-mail to your patch series.

A cover letter may be useful to introduce the changes you propose in the following cases:

- large number of commits in the series;
- deep impact of the changes in the rest of the project;
- RFC [4];
- whenever you feel it will help presenting your work, your choices, the review process, etc.

### 21.5.2. Patch revision changelog

When improvements are requested, the new revision of each commit should include a changelog of the modifications between each submission. Note that when your patch series is introduced by a cover letter, an overall changelog may be added to the cover letter in addition to the changelog in the individual commits. The best thing to rework a patch series is by interactive rebasing: `git rebase -i origin/master`. Consult the git manual for more information.

When added to the individual commits, this changelog is added when editing the commit message. Below the `Signed-off-by` section, add `---` and your changelog.

Although the changelog will be visible for the reviewers in the mail thread, as well as in patchwork, `git` will automatically ignores lines below `---` when the patch will be merged. This is the intended behavior: the changelog is not meant to be preserved forever in the `git` history of the project.

Hereafter the recommended layout:

    Patch title: short explanation, max 72 chars

    A paragraph that explains the problem, and how it manifests itself. If
    the problem is complex, it is OK to add more paragraphs. All paragraphs
    should be wrapped at 72 characters.

    A paragraph that explains the root cause of the problem. Again, more
    than on paragraph is OK.

    Finally, one or more paragraphs that explain how the problem is solved.
    Don't hesitate to explain complex solutions in detail.

    Signed-off-by: John DOE <john.doe@example.net>

    ---
    Changes v2 -> v3:
      - foo bar  (suggested by Jane)
      - bar buz

    Changes v1 -> v2:
      - alpha bravo  (suggested by John)
      - charly delta

Any patch revision should include the version number. The version number is simply composed of the letter `v` followed by an `integer` greater or equal to two (i.e. "PATCH v2", "PATCH v3" …).

This can be easily handled with `git format-patch` by using the option `--subject-prefix`:

    $ git format-patch --subject-prefix "PATCH v4" \
        -M -s -o outgoing origin/master

## 21.6. Reporting issues/bugs or getting help

Before reporting any issue, please check in the mailing list archive Chapter 5, Community resources whether someone has already reported and/or fixed a similar problem.

However you choose to report bugs or get help, either by opening a bug in the bug tracker Chapter 5, Community resources or by sending a mail to the mailing list Chapter 5, Community resources, there are a number of details to provide in order to help people reproduce and find a solution to the issue.

Try to think as if you were trying to help someone else; in that case, what would you need?

Here is a short list of details to provide in such case:

- host machine (OS/release)
- version of Buildroot
- target for which the build fails
- package(s) for which the build fails
- the command that fails and its output
- any information you think that may be relevant

Additionally, you should add the `.config` file (or if you know how, a `defconfig`; see Section 9.3, “Storing the Buildroot configuration”).

If some of these details are too large, do not hesitate to use a pastebin service. Note that not all available pastebin services will preserve Unix-style line terminators when downloading raw pastes. Following pastebin services are known to work correctly: - https://gist.github.com/ - http://code.bulix.org/

[4] RFC: (Request for comments) change proposal

# Part IV. Appendix

## Chapter 22. Makedev syntax documentation

The makedev syntax is used in several places in Buildroot to define changes to be made for permissions, or which device files to create and how to create them, in order to avoid calls to mknod.

This syntax is derived from the makedev utility, and more complete documentation can be found in the `package/makedevs/README` file.

It takes the form of a line for each file, with the following layout:

name | type | mode | uid | gid | major | minor | start | inc | count

There are a few non-trivial blocks here:

- `name` is the path to the file you want to create/modify

- `type` is the type of the file, being one of:

  - f: a regular file
  - d: a directory
  - c: a character device file
  - b: a block device file
  - p: a named pipe
- `mode`, `uid` and `gid` are the usual permissions settings
- `major` and `minor` are here for device files - set to - for other files
- `start`, `inc` and `count` are for when you want to create a batch of files, and can be reduced to a loop, beginning at `start`, incrementing its counter by `inc` until it reaches `count`

Let’s say you want to change the permissions of a given file; using this syntax, you will need to put:

    /usr/bin/foobar f       644     0       0       -       -       -       -       -

On the other hand, if you want to create the device file `/dev/hda` and the corresponding 15 files for the partitions, you will need for `/dev/hda`:

    /dev/hda        b       640     0       0       3       0       0       0       -

and then for device files corresponding to the partitions of `/dev/hda`, `/dev/hdaX`, `X` ranging from 1 to 15:

    /dev/hda        b       640     0       0       3       1       1       1       15

## Chapter 23. Makeusers syntax documentation

The syntax to create users is inspired by the makedev syntax, above, but is specific to Buildroot.

The syntax for adding a user is a space-separated list of fields, one user per line; the fields are:

username | uid | group | gid | password | home | shell | groups | comment

Where:

- `username` is the desired user name (aka login name) for the user. It can not be `root`, and must be unique. If set to `-`, then just a group will be created.
- `uid` is the desired UID for the user. It must be unique, and not `0`. If set to `-1`, then a unique UID will be computed by Buildroot in the range [1000…1999]
- `group` is the desired name for the user’s main group. It can not be `root`. If the group does not exist, it will be created.
- `gid` is the desired GID for the user’s main group. It must be unique, and not `0`. If set to `-1`, and the group does not already exist, then a unique GID will be computed by Buildroot in the range [1000..1999]
- `password` is the crypt(3)-encoded password. If prefixed with `!`, then login is disabled. If prefixed with `=`, then it is interpreted as clear-text, and will be crypt-encoded (using MD5). If prefixed with `!=`, then the password will be crypt-encoded (using MD5) and login will be disabled. If set to `*`, then login is not allowed.
- `home` is the desired home directory for the user. If set to -, no home directory will be created, and the user’s home will be `/`. Explicitly setting `home` to `/` is not allowed.
- `shell` is the desired shell for the user. If set to `-`, then `/bin/false` is set as the user’s shell.
- `groups` is the comma-separated list of additional groups the user should be part of. If set to `-`, then the user will be a member of no additional group. Missing groups will be created with an arbitrary `gid`.
- `comment` (aka GECOS field) is an almost-free-form text.

There are a few restrictions on the content of each field:

- except for `comment`, all fields are mandatory.
- except for `comment`, fields may not contain spaces.
- no field may contain a colon (`:`).

If `home` is not `-`, then the home directory, and all files below, will belong to the user and its main group.

Examples:

    foo -1 bar -1 !=blabla /home/foo /bin/sh alpha,bravo Foo user

This will create this user:

- `username` (aka login name) is: `foo`
- `uid` is computed by Buildroot
- main `group` is: `bar`
- main group `gid` is computed by Buildroot
- clear-text `password` is: `blabla`, will be crypt(3)-encoded, and login is disabled.
- `home` is: `/home/foo`
- `shell` is: `/bin/sh`
- `foo` is also a member of `groups`: `alpha` and `bravo`
- `comment` is: `Foo user`

    test 8000 wheel -1 = - /bin/sh - Test user

This will create this user:

- `username` (aka login name) is: `test`
- `uid` is : `8000`
- main `group` is: `wheel`
- main group `gid` is computed by Buildroot, and will use the value defined in the rootfs skeleton
- `password` is empty (aka no password).
- `home` is `/` but will not belong to `test`
- `shell` is: `/bin/sh`
- `test` is not a member of any additional `groups`
- `comment` is: `Test user`

## Chapter 24. List of target packages available in Buildroot

Packages | Target packages → …
--- | ---
a10disp | → Hardware handling
acl | → System tools
acpid | → Hardware handling
adwaita icon theme | → Libraries → Graphics
aespipe | → Miscellaneous
agent++ | → Libraries → Networking
aiccu | → Networking applications
aircrack-ng | → Networking applications
alsa-lib | → Libraries → Audio/Sound
alsa-utils | → Audio and video applications
alsamixergui | → Graphic libraries and applications (graphic/text)
am335x-pru-package | → Hardware handling
am33x-cm3 | → Hardware handling → Firmware
apitrace | → Graphic libraries and applications (graphic/text)
applewmproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
appres | → Graphic libraries and applications (graphic/text) → X11R7 Applications
apr | → Libraries → Other
apr-util | → Libraries → Other
argp-standalone | → Libraries → Other
argus | → Networking applications
armadillo | → Libraries → Other
arptables | → Networking applications
at | → Shell and utilities
atftp | → Networking applications
atk | → Libraries → Graphics
attr | → System tools
audiofile | → Libraries → Audio/Sound
aumix | → Audio and video applications
autossh | → Networking applications
avahi | → Networking applications
avrdude | → Hardware handling
axel | → Networking applications
b43-firmware | → Hardware handling → Firmware
bandwidthd | → Networking applications
bash | → Shell and utilities
bc | → Miscellaneous
bcache tools | → Hardware handling
bcusdk | → Networking applications
bdftopcf | → Graphic libraries and applications (graphic/text) → X11R7 Applications
beecrypt | → Libraries → Crypto
beforelight | → Graphic libraries and applications (graphic/text) → X11R7 Applications
bellagio | → Audio and video applications
berkeleydb | → Libraries → Database
bigreqsproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
bind | → Networking applications
binutils | → Development tools
biosdevname | → Hardware handling
bison (deprecated) | → Development tools
bitmap | → Graphic libraries and applications (graphic/text) → X11R7 Applications
blackbox (deprecated) | → Graphic libraries and applications (graphic/text)
bluez-utils | → Networking applications
bluez-utils 5.x | → Networking applications
bmon | → Networking applications
boa | → Networking applications
bonnie++ | → Debugging, profiling and benchmark
boost | → Libraries → Other
bootutils | → System tools
botan | → Libraries → Crypto
bridge-utils | → Networking applications
bsdiff | → Development tools
btrfs-progs | → Filesystem and flash utilities
bustle | → Development tools
BusyBox |
bwm-ng | → Networking applications
bzip2 | → Compressors and decompressors
c-ares | → Libraries → Networking
CA Certificates | → Libraries → Crypto
cache-calibrator | → Debugging, profiling and benchmark
cairo | → Libraries → Graphics
can-utils | → Networking applications
canfestival | → Libraries → Networking
cblas/clapack | → Libraries → Other
ccid | → Libraries → Hardware handling
ccrypt | → Shell and utilities
cdrkit | → Hardware handling
cegui06 | → Graphic libraries and applications (graphic/text)
celt051 | → Libraries → Audio/Sound
cgilua | → Interpreter languages and scripting → Lua libraries/modules
chrony | → Networking applications
cifs-utils | → Filesystem and flash utilities
civetweb | → Networking applications
cJSON | → Libraries → JSON/XML
clamav | → Miscellaneous
classpath | → Libraries → Other
collectd | → Miscellaneous
compositeproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
connman | → Networking applications
conntrack-tools | → Networking applications
copas | → Interpreter languages and scripting → Lua libraries/modules
coreutils | → System tools
cosmo | → Interpreter languages and scripting → Lua libraries/modules
coxpcall | → Interpreter languages and scripting → Lua libraries/modules
cppcms | → Libraries → Other
cppdb | → Libraries → Database
cppunit | → Development tools
cppzmq | → Libraries → Networking
cpuload | → System tools
cramfs | → Filesystem and flash utilities
crda | → Networking applications
cryptodev-linux | → Libraries → Crypto → cryptodev variant
cryptsetup | → Hardware handling
ctorrent | → Networking applications
cups | → Networking applications
curlftpfs (FUSE) | → Filesystem and flash utilities
cvs | → Development tools
cwiid | → Hardware handling
czmq | → Libraries → Networking
dado | → Interpreter languages and scripting → Lua libraries/modules
damageproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
dash | → Shell and utilities
dbus | → Hardware handling
dbus-c++ | → Hardware handling
dbus-glib | → Hardware handling
dbus-python | → Hardware handling
dbus-triggerd | → Hardware handling
dcron | → System tools
Declarative module | → Graphic libraries and applications (graphic/text)
DejaVu fonts | → Graphic libraries and applications (graphic/text)
devmem2 | → Hardware handling
dhcp (ISC) | → Networking applications
dhcpcd | → Networking applications
dhcpdump | → Networking applications
dhrystone | → Debugging, profiling and benchmark
dialog | → Shell and utilities
diffutils | → Development tools
dillo | → Graphic libraries and applications (graphic/text)
directfb | → Graphic libraries and applications (graphic/text)
directfb examples | → Graphic libraries and applications (graphic/text)
directfb virtual input extension | → Graphic libraries and applications (graphic/text)
distcc (deprecated) | → Development tools
dmalloc | → Debugging, profiling and benchmark
dmidecode | → Hardware handling
dmraid | → Hardware handling
dmxproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
dnsmasq | → Networking applications
docker | → Graphic libraries and applications (graphic/text)
dosfstools | → Filesystem and flash utilities
dovecot | → Mail
dovecot-pigeonhole | → Mail
dri2proto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
dri3proto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
dropbear | → Networking applications
dropwatch | → Debugging, profiling and benchmark
dsp-tools | → System tools
dstat | → Debugging, profiling and benchmark
dtach | → Shell and utilities
dtc (libfdt) | → Libraries → Hardware handling
dtv-scan-tables | → Hardware handling
duma | → Debugging, profiling and benchmark
dvb-apps | → Hardware handling
dvbsnoop | → Hardware handling
e2fsprogs | → Filesystem and flash utilities
e2tools | → Filesystem and flash utilities
ebtables | → Networking applications
ecryptfs-utils | → Filesystem and flash utilities
ed | → Text editors and viewers
editres | → Graphic libraries and applications (graphic/text) → X11R7 Applications
eeprog | → Hardware handling
eigen | → Libraries → Other
elfutils | → Libraries → Other
empty | → Miscellaneous
enchant | → Libraries → Text and terminal handling
encodings | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
enlightenment | → Graphic libraries and applications (graphic/text)
Enlightenment Foundation Libraries | → Graphic libraries and applications (graphic/text)
enscript | → Interpreter languages and scripting
erlang | → Interpreter languages and scripting
espeak | → Audio and video applications
ethtool | → Networking applications
eudev | → Hardware handling
evemu | → Hardware handling
evtest | → Hardware handling
exFAT (FUSE) | → Filesystem and flash utilities
exfat-utils | → Filesystem and flash utilities
exim | → Mail
expat | → Libraries → JSON/XML
expect | → Interpreter languages and scripting → tcl libraries/modules
expedite | → Graphic libraries and applications (graphic/text)
explorercanvas | → Libraries → Javascript
ezxml | → Libraries → JSON/XML
f2fs-tools | → Filesystem and flash utilities
faad2 | → Audio and video applications
faifa | → Networking applications
fan-ctrl | → Hardware handling
fb-test-app | → Graphic libraries and applications (graphic/text)
fbdump (Framebuffer Capture Tool) | → Graphic libraries and applications (graphic/text)
fbgrab | → Graphic libraries and applications (graphic/text)
fbset | → Graphic libraries and applications (graphic/text)
fbterm | → Graphic libraries and applications (graphic/text)
fbv | → Graphic libraries and applications (graphic/text)
fconfig | → Hardware handling
fdk-aac | → Libraries → Audio/Sound
feh | → Graphic libraries and applications (graphic/text)
fetchmail | → Mail
ffmpeg | → Audio and video applications
fftw | → Libraries → Other
file | → Shell and utilities
filemq | → Libraries → Networking
findutils | → Development tools
fio | → Debugging, profiling and benchmark
firmware-imx | → Hardware handling
fis | → Hardware handling
fixesproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
flac | → Audio and video applications
flann | → Libraries → Other
flashbench | → Filesystem and flash utilities
flashrom | → Hardware handling
flex | → Development tools
flickcurl | → Libraries → Networking
flite | → Audio and video applications
flot | → Libraries → Javascript
fltk | → Libraries → Graphics
fluxbox | → Graphic libraries and applications (graphic/text)
fmc | → Networking applications
fmlib | → Libraries → Networking
fmtools | → Hardware handling
font-adobe-100dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-adobe-75dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-adobe-utopia-100dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-adobe-utopia-75dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-adobe-utopia-type1 | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-alias | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-arabic-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-100dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-75dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-lucidatypewriter-100dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-lucidatypewriter-75dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-ttf | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bh-type1 | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bitstream-100dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bitstream-75dpi | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-bitstream-type1 | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-cronyx-cyrillic | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-cursor-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-daewoo-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-dec-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-ibm-type1 | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-isas-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-jis-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-micro-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-misc-cyrillic | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-misc-ethiopic | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-misc-meltho | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-misc-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-mutt-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-schumacher-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-screen-cyrillic | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-sony-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-sun-misc | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-util | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-winitzki-cyrillic | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
font-xfree86-type1 | → Graphic libraries and applications (graphic/text) → X11R7 Fonts
fontcacheproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
fontconfig | → Libraries → Graphics
fontsproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
fonttosfnt | → Graphic libraries and applications (graphic/text) → X11R7 Applications
foomatic_filters | → Networking applications
fping | → Networking applications
freerdp | → Graphic libraries and applications (graphic/text)
Freescale i.MX libraries | → Hardware handling
freetype | → Libraries → Graphics
fslsfonts | → Graphic libraries and applications (graphic/text) → X11R7 Applications
fstobdf | → Graphic libraries and applications (graphic/text) → X11R7 Applications
fswebcam | → Graphic libraries and applications (graphic/text)
ftop | → System tools
fxload | → Hardware handling
gadgetfs-test | → Hardware handling
gamin | → Libraries → Filesystem
gawk | → Development tools
gd | → Libraries → Graphics
gdb | → Debugging, profiling and benchmark
gdbm | → Libraries → Database
gdk-pixbuf | → Libraries → Graphics
genext2fs | → Filesystem and flash utilities
genpart | → Filesystem and flash utilities
genromfs | → Filesystem and flash utilities
geoip | → Libraries → Networking
gesftpserver | → Networking applications
getent | → System tools
gettext | → Development tools
giblib | → Libraries → Graphics
git | → Development tools
glib-networking | → Libraries → Networking
glibmm | → Libraries → Other
glm | → Libraries → Other
glproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
gmp | → Libraries → Other
gmpc | → Graphic libraries and applications (graphic/text)
gnu-efi | → Libraries → Hardware handling
gnuchess | → Games
gnupg | → Shell and utilities
gnupg2 | → Shell and utilities
gnuplot | → Graphic libraries and applications (graphic/text)
gnutls | → Libraries → Crypto
gob2 (deprecated) | → Graphic libraries and applications (graphic/text)
Google font directory | → Miscellaneous
google-breakpad | → Debugging, profiling and benchmark
gperf | → Development tools
gpm | → Hardware handling
gpsd | → Hardware handling
gptfdisk | → Hardware handling
gpu-viv-bin-mx6q | → Hardware handling
gqview | → Graphic libraries and applications (graphic/text)
grantlee | → Graphic libraries and applications (graphic/text)
grep | → Development tools
gsl | → Libraries → Other
gst-dsp | → Audio and video applications
gst-ffmpeg | → Audio and video applications
gst-fsl-plugins | → Audio and video applications
gst-omapfb | → Audio and video applications
gst-omx | → Audio and video applications
gst-plugin-x170 | → Audio and video applications
gst-plugins-bad | → Audio and video applications
gst-plugins-base | → Audio and video applications
gst-plugins-good | → Audio and video applications
gst-plugins-ugly | → Audio and video applications
gst1-libav | → Audio and video applications
gst1-plugins-bad | → Audio and video applications
gst1-plugins-base | → Audio and video applications
gst1-plugins-good | → Audio and video applications
gst1-plugins-ugly | → Audio and video applications
gst1-validate | → Audio and video applications
gstreamer 0.10 | → Audio and video applications
gstreamer 1.x | → Audio and video applications
gtest | → Libraries → Other
gtk engines | → Libraries → Graphics
gtkperf (performance test for GTK2) | → Graphic libraries and applications (graphic/text)
gutenprint | → Networking applications
gvfs | → Hardware handling
gzip | → Compressors and decompressors
harfbuzz | → Libraries → Graphics
haserl | → Interpreter languages and scripting
haveged | → Miscellaneous
hdparm | → Hardware handling
heirloom-mailx | → Mail
hiawatha | → Networking applications
hicolor (default theme) | → Libraries → Graphics → GTK Themes
hicolor icon theme | → Libraries → Graphics
hostapd | → Networking applications
hplip | → Networking applications
htop | → System tools
httping | → Networking applications
hwdata | → Hardware handling
i2c-tools | → Hardware handling
iceauth | → Graphic libraries and applications (graphic/text) → X11R7 Applications
ico | → Graphic libraries and applications (graphic/text) → X11R7 Applications
icu | → Libraries → Text and terminal handling
ifplugd | → Networking applications
iftop | → Networking applications
igh-ethercat | → Networking applications
igmpproxy | → Networking applications
imagemagick | → Graphic libraries and applications (graphic/text)
imlib2 | → Libraries → Graphics
imx-lib | → Hardware handling
imx-vpu | → Hardware handling
inadyn | → Networking applications
infozip | → Compressors and decompressors
inotify-tools | → Shell and utilities
input-event-daemon | → Hardware handling
input-tools | → Hardware handling
inputproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
intel-microcode | → Hardware handling
intltool | → Development tools
iostat | → Hardware handling
iozone | → Debugging, profiling and benchmark
iperf | → Networking applications
ipkg | → Package managers
ipmitool | → Hardware handling
iproute2 | → Networking applications
iprutils | → System tools
ipsec-tools | → Networking applications
ipset | → Networking applications
iptables | → Networking applications
iptraf-ng | → Networking applications
iputils | → Networking applications
irda-utils | → Hardware handling
iucode-tool | → Hardware handling
iw | → Networking applications
jack2 | → Audio and video applications
jamvm | → Interpreter languages and scripting
jansson | → Libraries → JSON/XML
jasper | → Libraries → Graphics
jhead | → Graphic libraries and applications (graphic/text)
jimtcl | → Interpreter languages and scripting
joe | → Text editors and viewers
jpeg | → Libraries → Graphics → jpeg variant
jpeg-turbo | → Libraries → Graphics → jpeg variant
jq | → Development tools
jQuery | → Libraries → Javascript
jQuery keyboard | → Libraries → Javascript
jQuery UI | → Libraries → Javascript
jQuery UI themes | → Libraries → Javascript
jquery-mobile | → Libraries → Javascript
jQuery-Sparkline | → Libraries → Javascript
jQuery-Validation | → Libraries → Javascript
jsmin | → Libraries → Javascript
json-c | → Libraries → JSON/XML
json-glib | → Libraries → JSON/XML
json-javascript | → Libraries → Javascript
kbd | → Hardware handling
kbproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
kexec | → Debugging, profiling and benchmark
kexec-lite | → Debugging, profiling and benchmark
keyutils | → System tools
kismet | → Networking applications
kmod | → System tools
knock | → Networking applications
kobs-ng | → Filesystem and flash utilities
ktap | → Debugging, profiling and benchmark
lame | → Audio and video applications
latencytop | → Debugging, profiling and benchmark
lbase64 | → Interpreter languages and scripting → Lua libraries/modules
LBreakout2 | → Games
lcdapi | → Libraries → Hardware handling
lcdproc | → Hardware handling
lcms2 | → Libraries → Graphics
leafnode2 | → Networking applications
leafpad | → Graphic libraries and applications (graphic/text)
less | → Text editors and viewers
lesstif | → Libraries → Graphics
lftp | → Networking applications
libaio | → Libraries → Hardware handling
libao | → Libraries → Audio/Sound
libarchive | → Libraries → Compression and decompression
libargtable2 | → Libraries → Other
libart | → Libraries → Graphics
libass | → Libraries → Multimedia
libassuan | → Libraries → Crypto
libatasmart | → Libraries → Hardware handling
libatomic_ops | → Libraries → Other
libbluray | → Libraries → Multimedia
libbsd | → Libraries → Other
libcap | → Libraries → Other
libcap-ng | → Libraries → Other
libcdaudio | → Libraries → Audio/Sound
libcdio | → Libraries → Audio/Sound
libcec | → Libraries → Hardware handling
libcgi | → Libraries → Networking
libcgicc | → Libraries → Networking
libcgroup | → Libraries → Other
libcofi | → Libraries → Other
libconfig | → Libraries → Filesystem
libconfuse | → Libraries → Filesystem
libcue | → Libraries → Audio/Sound
libcuefile | → Libraries → Audio/Sound
libcurl | → Libraries → Networking
libdaemon | → Libraries → Other
libdmtx | → Libraries → Graphics
libdmx | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libdnet | → Libraries → Networking
libdrm | → Libraries → Graphics
libdvbcsa | → Libraries → Multimedia
libdvbsi | → Libraries → Multimedia
libdvdnav | → Libraries → Multimedia
libdvdread | → Libraries → Multimedia
libebml | → Libraries → Multimedia
libecore | → Graphic libraries and applications (graphic/text)
libedbus | → Graphic libraries and applications (graphic/text)
libedit | → Libraries → Text and terminal handling
libedje | → Graphic libraries and applications (graphic/text)
libee | → Libraries → Other
libeet | → Graphic libraries and applications (graphic/text)
libefreet | → Graphic libraries and applications (graphic/text)
libeina | → Graphic libraries and applications (graphic/text)
libeio | → Graphic libraries and applications (graphic/text)
libelementary | → Graphic libraries and applications (graphic/text)
libembryo | → Graphic libraries and applications (graphic/text)
libenca | → Libraries → Text and terminal handling
Liberation (Free fonts) | → Graphic libraries and applications (graphic/text)
libesmtp | → Mail
libestr | → Libraries → Text and terminal handling
libethumb | → Graphic libraries and applications (graphic/text)
libev | → Libraries → Other
libevas | → Graphic libraries and applications (graphic/text)
libevas generic loaders | → Graphic libraries and applications (graphic/text)
libevdev | → Libraries → Other
libevent | → Libraries → Other
libexif | → Libraries → Graphics
libeXosip2 | → Libraries → Networking
libfcgi | → Libraries → Networking
libffi | → Libraries → Other
libfontenc | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libfreefare | → Libraries → Hardware handling
libfribidi | → Libraries → Text and terminal handling
libFS | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libfslcodec | → Libraries → Multimedia
libfslparser | → Libraries → Multimedia
libfslvpuwrap | → Libraries → Multimedia
libftdi | → Libraries → Hardware handling
libfuse | → Libraries → Filesystem
libgail | → Libraries → Graphics
libgc | → Libraries → Other
libgcrypt | → Libraries → Crypto
libgeotiff | → Libraries → Graphics
libglade | → Libraries → Graphics
libglew | → Libraries → Graphics
libglib2 | → Libraries → Other
libglu | → Libraries → Graphics
libgpg-error | → Libraries → Crypto
libgpgme | → Libraries → Crypto
libgsasl | → Libraries → Networking
libgtk2 | → Libraries → Graphics
libgtk3 | → Libraries → Graphics
libhid | → Libraries → Hardware handling
libical | → Libraries → Other
libICE | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libiconv | → Libraries → Text and terminal handling
libid3tag | → Libraries → Audio/Sound
libidn | → Libraries → Networking
libinput | → Libraries → Hardware handling
libiqrf | → Libraries → Hardware handling
libiscsi | → Libraries → Networking
libjson | → Libraries → JSON/XML
libksba | → Libraries → Crypto
libllcp | → Libraries → Hardware handling
liblo | → Libraries → Audio/Sound
liblockfile | → Libraries → Filesystem
liblog4c-localtime | → Libraries → Logging
liblogging | → Libraries → Logging
libmad | → Libraries → Audio/Sound
libmatroska | → Libraries → Multimedia
libmbim | → Libraries → Hardware handling
libmbus | → Libraries → Networking
libmcrypt | → Libraries → Crypto
libmemcached | → Libraries → Networking
libmhash | → Libraries → Crypto
libmicrohttpd | → Libraries → Networking
libmms | → Libraries → Multimedia
libmnl | → Libraries → Networking
libmodbus | → Libraries → Networking
libmodplug | → Libraries → Audio/Sound
libmpd | → Libraries → Audio/Sound
libmpdclient | → Libraries → Audio/Sound
libmpeg2 | → Libraries → Multimedia
libndp | → Libraries → Networking
libneon | → Libraries → Networking
libnetfilter_acct | → Libraries → Networking
libnetfilter_conntrack | → Libraries → Networking
libnetfilter_cthelper | → Libraries → Networking
libnetfilter_cttimeout | → Libraries → Networking
libnetfilter_log | → Libraries → Networking
libnetfilter_queue | → Libraries → Networking
libnfc | → Libraries → Hardware handling
libnfnetlink | → Libraries → Networking
libnfs | → Libraries → Filesystem
libnftnl | → Libraries → Networking
libnl | → Libraries → Networking
libnspr | → Libraries → Other
libnss | → Libraries → Crypto
liboauth | → Libraries → Networking
libogg | → Libraries → Multimedia
liboping | → Libraries → Networking
libosip2 | → Libraries → Networking
libpcap | → Libraries → Networking
libpciaccess | → Libraries → Hardware handling
libpfm4 | → Libraries → Other
libphidget | → Libraries → Hardware handling
libplayer | → Libraries → Multimedia
libplist | → Libraries → Other
libpng | → Libraries → Graphics
libpthread-stubs | → Libraries → Other
libpthsem | → Libraries → Other
libqmi | → Libraries → Hardware handling
libqrencode | → Libraries → Graphics
libraw | → Libraries → Graphics
libraw1394 | → Libraries → Hardware handling
libreplaygain | → Libraries → Audio/Sound
librsvg | → Libraries → Graphics
librsync | → Libraries → Networking
librtlsdr | → Libraries → Hardware handling
librtmp | → Libraries → Networking
libsamplerate | → Libraries → Audio/Sound
libseccomp | → Libraries → Other
libsecret | → Libraries → Crypto
libsepol | → Libraries → Security
libserial | → Libraries → Hardware handling
libsexy | → Graphic libraries and applications (graphic/text)
libsha1 | → Libraries → Crypto
libshairplay | → Libraries → Networking
libshout | → Libraries → Networking
libsigc++ | → Libraries → Other
libsigsegv | → Libraries → Other
libSM | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libsndfile | → Libraries → Audio/Sound
libsoc | → Libraries → Hardware handling
libsocketcan | → Libraries → Networking
libsoup | → Libraries → Networking
libsoxr | → Libraries → Audio/Sound
libssh2 | → Libraries → Crypto
libstrophe | → Libraries → Networking
libsvg | → Libraries → Graphics
libsvg-cairo | → Libraries → Graphics
libsvgtiny | → Libraries → Graphics
libsysfs | → Libraries → Filesystem
libtasn1 | → Libraries → Other
libtheora | → Libraries → Multimedia
libtirpc | → Libraries → Networking
libtool | → Development tools
libtorrent | → Libraries → Networking
libtpl | → Libraries → Other
libubox | → Libraries → Other
libuci | → Libraries → Other
libungif | → Libraries → Graphics
libunistring | → Libraries → Text and terminal handling
libunwind | → Libraries → Other
libupnp | → Libraries → Networking
libupnpp | → Libraries → Networking
liburcu | → Libraries → Other
libusb | → Libraries → Hardware handling
libusb-compat | → Libraries → Hardware handling
libuv | → Libraries → Other
libv4l | → Libraries → Hardware handling
libva | → Libraries → Graphics
libva-intel-driver | → Libraries → Graphics
libvncserver | → Libraries → Networking
libvorbis | → Libraries → Audio/Sound
libvpx | → Audio and video applications
libwebsockets | → Libraries → Networking
libX11 | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXau | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXaw | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libxcb | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXcomposite | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXcursor | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXdamage | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXdmcp | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXext | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXfixes | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXfont | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXft | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXi | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXinerama | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libxkbcommon | → Libraries → Hardware handling
libxkbfile | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libxml++ | → Libraries → JSON/XML
libxml2 | → Libraries → JSON/XML
libxmlrpc | → Libraries → JSON/XML
libXmu | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXpm | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXrandr | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXrender | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXres | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXScrnSaver | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libxshmfence | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libxslt | → Libraries → JSON/XML
libXt | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXtst | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXv | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXvMC | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXxf86dga | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libXxf86vm | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
libyaml | → Libraries → JSON/XML
lighttpd | → Networking applications
linenoise | → Libraries → Text and terminal handling
linknx | → Networking applications
links | → Networking applications
linphone | → Networking applications
linux-firmware | → Hardware handling → Firmware
linux-fusion communication layer for DirectFB multi | → Graphic libraries and applications (graphic/text)
linux-pam | → Libraries → Other
linux-zigbee | → Networking applications
listres | → Graphic libraries and applications (graphic/text) → X11R7 Applications
LiTE (toolbox engine) | → Graphic libraries and applications (graphic/text)
live555 | → Libraries → Multimedia
ljlinenoise | → Interpreter languages and scripting → Lua libraries/modules
ljsyscall | → Interpreter languages and scripting → Lua libraries/modules
lm-sensors | → Hardware handling
lmbench | → Debugging, profiling and benchmark
lockdev | → Libraries → Filesystem
lockfile programs | → Shell and utilities
log4cplus | → Libraries → Logging
log4cxx | → Libraries → Logging
logrotate | → Shell and utilities
logsurfer | → Shell and utilities
lpeg | → Interpreter languages and scripting → Lua libraries/modules
lpty | → Interpreter languages and scripting → Lua libraries/modules
lrandom | → Interpreter languages and scripting → Lua libraries/modules
lrzsz | → Networking applications
lshw | → Hardware handling
lsof | → Debugging, profiling and benchmark
lsqlite3 | → Interpreter languages and scripting → Lua libraries/modules
lsuio | → Hardware handling
ltp-testsuite | → Debugging, profiling and benchmark
ltrace | → Debugging, profiling and benchmark
LTris | → Games
lttng-babeltrace | → Debugging, profiling and benchmark
lttng-libust | → Libraries → Other
lttng-modules | → Debugging, profiling and benchmark
lttng-tools | → Debugging, profiling and benchmark
lua | → Interpreter languages and scripting
lua-cjson | → Interpreter languages and scripting → Lua libraries/modules
lua-coat | → Interpreter languages and scripting → Lua libraries/modules
lua-coatpersistent | → Interpreter languages and scripting → Lua libraries/modules
lua-csnappy | → Interpreter languages and scripting → Lua libraries/modules
lua-ev | → Interpreter languages and scripting → Lua libraries/modules
lua-messagepack | → Interpreter languages and scripting → Lua libraries/modules
lua-msgpack-native | → Interpreter languages and scripting → Lua libraries/modules
lua-testmore | → Interpreter languages and scripting → Lua libraries/modules
luabitop | → Interpreter languages and scripting → Lua libraries/modules
luacrypto | → Interpreter languages and scripting → Lua libraries/modules
luaexpat | → Interpreter languages and scripting → Lua libraries/modules
luaexpatutils | → Interpreter languages and scripting → Lua libraries/modules
luafilesystem | → Interpreter languages and scripting → Lua libraries/modules
luajit | → Interpreter languages and scripting
luajson | → Interpreter languages and scripting → Lua libraries/modules
lualogging | → Interpreter languages and scripting → Lua libraries/modules
luaposix | → Interpreter languages and scripting → Lua libraries/modules
luasec | → Interpreter languages and scripting → Lua libraries/modules
luasocket | → Interpreter languages and scripting → Lua libraries/modules
luasql-sqlite3 | → Interpreter languages and scripting → Lua libraries/modules
luit | → Graphic libraries and applications (graphic/text) → X11R7 Applications
lunit | → Interpreter languages and scripting → Lua libraries/modules
lvm2 & device mapper | → Hardware handling
lxc | → System tools
lz4 | → Compressors and decompressors
lzip | → Compressors and decompressors
lzlib | → Interpreter languages and scripting → Lua libraries/modules
lzo | → Libraries → Compression and decompression
lzop | → Compressors and decompressors
m4 (deprecated) | → Development tools
macchanger | → Networking applications
madplay | → Audio and video applications
make | → Development tools
makedepend | → Graphic libraries and applications (graphic/text) → X11R7 Utilities
makedevs | → Filesystem and flash utilities
Matchbox Desktop | → Graphic libraries and applications (graphic/text)
Matchbox Panel | → Graphic libraries and applications (graphic/text)
Matchbox session common files | → Graphic libraries and applications (graphic/text)
Matchbox Virtual Keyboard | → Graphic libraries and applications (graphic/text)
MatchBox Window Manager | → Graphic libraries and applications (graphic/text)
mcookie | → Graphic libraries and applications (graphic/text) → X11R7 Utilities
mcrypt | → Miscellaneous
mdadm | → Hardware handling
media-ctl | → Hardware handling
mediastreamer | → Libraries → Multimedia
memcached | → Networking applications
memstat | → Debugging, profiling and benchmark
memtester | → Hardware handling
mesa3d | → Graphic libraries and applications (graphic/text)
mesa3d-demos | → Graphic libraries and applications (graphic/text)
metacity | → Graphic libraries and applications (graphic/text)
midori | → Graphic libraries and applications (graphic/text)
mii-diag | → Networking applications
Mini-XML | → Libraries → JSON/XML
minicom | → Hardware handling
minidlna | → Networking applications
mkfontdir | → Graphic libraries and applications (graphic/text) → X11R7 Applications
mkfontscale | → Graphic libraries and applications (graphic/text) → X11R7 Applications
mmc-utils | → Filesystem and flash utilities
mobile-broadband-provider-info | → Miscellaneous
modemmanager | → Networking applications
modplugtools | → Audio and video applications
mongoose | → Networking applications
mongrel2 | → Networking applications
monit | → System tools
mono | → Interpreter languages and scripting
mp4v2 | → Libraries → Audio/Sound
mpc | → Libraries → Other
mpd | → Audio and video applications
mpdecimal | → Libraries → Other
mpfr | → Libraries → Other
mpg123 | → Audio and video applications
mplayer | → Audio and video applications
mrouted | → Networking applications
msgpack | → Libraries → Other
msmtp | → Mail
mtd, jffs2 and ubi/ubifs tools | → Filesystem and flash utilities
mtdev | → Libraries → Hardware handling
mtdev2tuio | → Libraries → Other
mtools | → Filesystem and flash utilities
mtr | → Networking applications
Multimedia Module | → Graphic libraries and applications (graphic/text)
musepack | → Audio and video applications
mutt | → Mail
MySQL | → Libraries → Database
nano | → Text editors and viewers
nanocom | → Hardware handling
nbd | → Networking applications
ncdu | → System tools
ncftp | → Networking applications
ncmpc | → Audio and video applications
ncurses | → Libraries → Text and terminal handling
ndisc6 tools | → Networking applications
ne10 | → Libraries → Hardware handling
neard | → Hardware handling
neardal | → Libraries → Hardware handling
net-tools | → Networking applications
netatalk | → Networking applications
netcat | → Networking applications
netcat-openbsd | → Networking applications
netperf | → Debugging, profiling and benchmark
netplug | → Networking applications
netsnmp | → Networking applications
netstat-nat | → Networking applications
nettle | → Libraries → Crypto
networkmanager | → Networking applications
newt | → Libraries → Text and terminal handling
nfacct | → Networking applications
nfs-utils | → Filesystem and flash utilities
nftables | → Networking applications
nginx | → Networking applications
ngircd | → Networking applications
ngrep | → Networking applications
nmap | → Networking applications
nodejs | → Interpreter languages and scripting
noip | → Networking applications
nss-mdns | → Libraries → Networking
ntfs-3g | → Filesystem and flash utilities
ntp | → Networking applications
numactl | → System tools
nut | → System tools
nuttcp | → Networking applications
ocf-linux | → Libraries → Crypto → cryptodev variant
oclock | → Graphic libraries and applications (graphic/text) → X11R7 Applications
ocrad | → Graphic libraries and applications (graphic/text)
odhcploc | → Networking applications
ofono | → Hardware handling
ola (open lighting architecture) | → Hardware handling
olsrd | → Networking applications
omniorb | → Libraries → Networking
on2-8170-libs | → Audio and video applications
on2-8170-modules | → Hardware handling
open2300 | → Hardware handling
opencore-amr | → Libraries → Audio/Sound
opencv | → Libraries → Graphics
openntpd | → Networking applications
openobex | → Networking applications
openocd | → Hardware handling
openpgm | → Libraries → Networking
openpowerlink | → Hardware handling
openssh | → Networking applications
openssl | → Libraries → Crypto
openswan | → Networking applications
OpenTyrian | → Games
OpenTyrian data | → Games
openvmtools | → System tools
openvpn | → Networking applications
opkg | → Package managers
oprofile | → Debugging, profiling and benchmark
opus | → Libraries → Audio/Sound
opus-tools | → Audio and video applications
orbit | → Interpreter languages and scripting → Lua libraries/modules
orc | → Libraries → Other
oRTP | → Libraries → Networking
owl-linux | → Hardware handling
p11-kit | → Libraries → Other
p910nd | → Networking applications
pango | → Libraries → Graphics
parted | → Hardware handling
patch | → Development tools
pax-utils | → Debugging, profiling and benchmark
pciutils | → Hardware handling
pcmanfm | → Graphic libraries and applications (graphic/text)
pcre | → Libraries → Text and terminal handling
pcsc-lite | → Libraries → Hardware handling
perf | → Debugging, profiling and benchmark
perl | → Interpreter languages and scripting
perl-datetime-tiny | → Interpreter languages and scripting → Perl libraries/modules
perl-gd | → Interpreter languages and scripting → Perl libraries/modules
perl-gdgraph | → Interpreter languages and scripting → Perl libraries/modules
perl-gdtextutil | → Interpreter languages and scripting → Perl libraries/modules
perl-io-socket-ssl | → Interpreter languages and scripting → Perl libraries/modules
perl-json-tiny | → Interpreter languages and scripting → Perl libraries/modules
perl-mojolicious | → Interpreter languages and scripting → Perl libraries/modules
perl-net-ssleay | → Interpreter languages and scripting → Perl libraries/modules
perl-path-tiny | → Interpreter languages and scripting → Perl libraries/modules
perl-try-tiny | → Interpreter languages and scripting → Perl libraries/modules
perl-xml-libxml | → Interpreter languages and scripting → Perl libraries/modules
perl-xml-namespacesupport | → Interpreter languages and scripting → Perl libraries/modules
perl-xml-sax | → Interpreter languages and scripting → Perl libraries/modules
perl-xml-sax-base | → Interpreter languages and scripting → Perl libraries/modules
phidgetwebservice | → Networking applications
php | → Interpreter languages and scripting
php-geoip | → Interpreter languages and scripting → External php extensions
php-gnupg | → Interpreter languages and scripting → External php extensions
php-imagick | → Interpreter languages and scripting → External php extensions
php-memcached | → Interpreter languages and scripting → External php extensions
php-ssh2 | → Interpreter languages and scripting → External php extensions
php-yaml | → Interpreter languages and scripting → External php extensions
php-zmq | → Interpreter languages and scripting → External php extensions
picocom | → Hardware handling
pifmrds | → Hardware handling
pinentry | → Shell and utilities
pixman | → Libraries → Graphics
pkgconf | → Development tools
poco | → Libraries → Other
polarssl | → Libraries → Crypto
polkit | → System tools
poppler | → Libraries → Graphics
popt | → Libraries → Text and terminal handling
portaudio | → Libraries → Audio/Sound
portmap | → Networking applications
postgresql | → Libraries → Database
powerpc-utils | → System tools
pppd | → Networking applications
pps-tools | → Hardware handling
pptp-linux | → Networking applications
PrBoom | → Games
presentproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
procps-ng | → System tools
proftpd | → Networking applications
protobuf | → Libraries → Other
protobuf-c | → Libraries → Other
proxychains-ng | → Networking applications
psmisc | → System tools
psplash | → Graphic libraries and applications (graphic/text)
ptpd | → Networking applications
ptpd2 | → Networking applications
pulseaudio | → Audio and video applications
pure-ftpd | → Networking applications
pv | → Debugging, profiling and benchmark
pwgen | → System tools
python | → Interpreter languages and scripting
python-bottle | → Interpreter languages and scripting → external python modules
python-cffi | → Interpreter languages and scripting → external python modules
python-configobj | → Interpreter languages and scripting → external python modules
python-configshell-fb | → Interpreter languages and scripting → external python modules
python-crc16 | → Interpreter languages and scripting → external python modules
python-daemon | → Interpreter languages and scripting → external python modules
python-dialog | → Interpreter languages and scripting → external python modules
python-dpkt | → Interpreter languages and scripting → external python modules
python-flup | → Interpreter languages and scripting → external python modules
python-id3 | → Interpreter languages and scripting → external python modules
python-ipy | → Interpreter languages and scripting → external python modules
python-ipython | → Interpreter languages and scripting → external python modules
python-json-schema-validator | → Interpreter languages and scripting → external python modules
python-keyring | → Interpreter languages and scripting → external python modules
python-libconfig | → Interpreter languages and scripting → external python modules
python-mad | → Interpreter languages and scripting → external python modules
python-meld3 | → Interpreter languages and scripting → external python modules
python-msgpack | → Interpreter languages and scripting → external python modules
python-netifaces | → Interpreter languages and scripting → external python modules
python-nfc | → Interpreter languages and scripting → external python modules
python-numpy | → Interpreter languages and scripting → external python modules
python-posix-ipc | → Interpreter languages and scripting → external python modules
python-protobuf | → Interpreter languages and scripting → external python modules
python-pyasn | → Interpreter languages and scripting → external python modules
python-pycrypto | → Interpreter languages and scripting → external python modules
python-pygame | → Interpreter languages and scripting → external python modules
python-pyparsing | → Interpreter languages and scripting → external python modules
python-pypcap | → Interpreter languages and scripting → external python modules
python-pyro | → Interpreter languages and scripting → external python modules
python-pysnmp | → Interpreter languages and scripting → external python modules
python-pysnmp-apps | → Interpreter languages and scripting → external python modules
python-pysnmp-mibs | → Interpreter languages and scripting → external python modules
python-pyusb | → Interpreter languages and scripting → external python modules
python-pyzmq | → Interpreter languages and scripting → external python modules
python-rtslib-fb | → Interpreter languages and scripting → external python modules
python-serial | → Interpreter languages and scripting → external python modules
python-setuptools | → Interpreter languages and scripting → external python modules
python-simplejson | → Interpreter languages and scripting → external python modules
python-thrift | → Interpreter languages and scripting → external python modules
python-tornado | → Interpreter languages and scripting → external python modules
python-urwid | → Interpreter languages and scripting → external python modules
python-versiontools | → Interpreter languages and scripting → external python modules
python3 | → Interpreter languages and scripting
qdecoder | → Libraries → Networking
QEMU | → Miscellaneous
qextserialport | → Graphic libraries and applications (graphic/text)
qhull | → Libraries → Other
qjson | → Graphic libraries and applications (graphic/text)
qlibc | → Libraries → Other
Qt | → Graphic libraries and applications (graphic/text)
Qt5 | → Graphic libraries and applications (graphic/text)
qt5base | → Graphic libraries and applications (graphic/text)
qt5connectivity | → Graphic libraries and applications (graphic/text)
qt5declarative | → Graphic libraries and applications (graphic/text)
qt5enginio | → Graphic libraries and applications (graphic/text)
qt5graphicaleffects | → Graphic libraries and applications (graphic/text)
qt5imageformats | → Graphic libraries and applications (graphic/text)
qt5multimedia | → Graphic libraries and applications (graphic/text)
qt5quick1 | → Graphic libraries and applications (graphic/text)
qt5quickcontrols | → Graphic libraries and applications (graphic/text)
qt5script | → Graphic libraries and applications (graphic/text)
qt5sensors | → Graphic libraries and applications (graphic/text)
qt5serialport | → Graphic libraries and applications (graphic/text)
qt5svg | → Graphic libraries and applications (graphic/text)
qt5webkit | → Graphic libraries and applications (graphic/text)
qt5webkit examples | → Graphic libraries and applications (graphic/text)
qt5websockets | → Graphic libraries and applications (graphic/text)
qt5x11extras | → Graphic libraries and applications (graphic/text)
qt5xmlpatterns | → Graphic libraries and applications (graphic/text)
qtuio | → Graphic libraries and applications (graphic/text)
quagga | → Networking applications
quota | → System tools
qwt | → Graphic libraries and applications (graphic/text)
radvd | → Networking applications
ramspeed | → Debugging, profiling and benchmark
ramspeed/smp | → Debugging, profiling and benchmark
randrproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
rapidjson | → Libraries → JSON/XML
rdesktop | → Graphic libraries and applications (graphic/text)
read-edid | → Hardware handling
readline | → Libraries → Text and terminal handling
recordproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
redis | → Libraries → Database
renderproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
resourceproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
rgb | → Graphic libraries and applications (graphic/text) → X11R7 Applications
rings | → Interpreter languages and scripting → Lua libraries/modules
rng-tools | → Hardware handling
roxml | → Libraries → JSON/XML
rp-pppoe | → Networking applications
rpcbind | → Networking applications
rpi-firmware | → Hardware handling → Firmware
rpi-userland | → Hardware handling
rpm | → Package managers
rrdtool | → Graphic libraries and applications (graphic/text)
rsh-redone | → Networking applications
rstart | → Graphic libraries and applications (graphic/text) → X11R7 Applications
rsync | → Networking applications
rsyslog | → System tools
rt-tests | → Debugging, profiling and benchmark
rtai | → Real-Time
rtorrent | → Networking applications
rtptools | → Networking applications
rubix | → Games
ruby | → Interpreter languages and scripting
samba | → Networking applications
samba4 | → Networking applications
sane-backends | → Hardware handling
SawMan (Window Manager) | → Graphic libraries and applications (graphic/text)
schifra | → Libraries → Other
sconeserver | → Networking applications
screen | → Shell and utilities
Script Module | → Graphic libraries and applications (graphic/text)
scripts | → Graphic libraries and applications (graphic/text) → X11R7 Applications
scrnsaverproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
SDL | → Graphic libraries and applications (graphic/text)
SDL_gfx | → Graphic libraries and applications (graphic/text)
SDL_image | → Graphic libraries and applications (graphic/text)
SDL_mixer | → Graphic libraries and applications (graphic/text)
SDL_net | → Graphic libraries and applications (graphic/text)
SDL_sound | → Graphic libraries and applications (graphic/text)
SDL_TTF | → Graphic libraries and applications (graphic/text)
sdparm | → Hardware handling
sed | → Development tools
ser2net | → Networking applications
sessreg | → Graphic libraries and applications (graphic/text) → X11R7 Applications
setserial | → Hardware handling
setxkbmap | → Graphic libraries and applications (graphic/text) → X11R7 Applications
sg3-utils | → Hardware handling
shairport-sync | → Networking applications
shared-mime-info | → Miscellaneous
shareware Doom WAD file | → Games
showfont | → Graphic libraries and applications (graphic/text) → X11R7 Applications
simicsfs | → Filesystem and flash utilities
sispmctl | → Hardware handling
slang | → Libraries → Text and terminal handling
slirp | → Libraries → Networking
smack | → System tools
smartmontools | → Hardware handling
smcroute | → Networking applications
smproxy | → Graphic libraries and applications (graphic/text) → X11R7 Applications
smstools3 | → Hardware handling
snappy | → Libraries → Compression and decompression
snmp++ | → Libraries → Networking
snowball-hdmiservice | → Hardware handling
snowball-init | → Miscellaneous
socat | → Networking applications
socketcand | → Networking applications
sound-theme-borealis | → Miscellaneous
sound-theme-freedesktop | → Miscellaneous
sox | → Audio and video applications
spawn-fcgi | → Networking applications
speex | → Libraries → Audio/Sound
spice protocol | → Networking applications
spice server | → Networking applications
spidev_test | → Debugging, profiling and benchmark
sqlcipher | → Libraries → Database
sqlite | → Libraries → Database
squashfs | → Filesystem and flash utilities
squid | → Networking applications
sredird | → Hardware handling
sshfs (FUSE) | → Filesystem and flash utilities
sshpass | → Networking applications
sstrip | → Development tools
startup-notification | → Libraries → Other
statserial | → Hardware handling
strace | → Debugging, profiling and benchmark
stress | → Debugging, profiling and benchmark
strongswan | → Networking applications
stunnel | → Networking applications
subversion | → Development tools
sudo | → Shell and utilities
sunxi nand-part | → Filesystem and flash utilities
sunxi script.bin board file | → Hardware handling → Firmware
sunxi-cedarx | → Hardware handling
sunxi-mali | → Hardware handling
supervisor | → System tools
SVG Module | → Graphic libraries and applications (graphic/text)
sylpheed | → Mail
synergy | → Graphic libraries and applications (graphic/text)
syslogd & klogd | → System tools
sysprof | → Debugging, profiling and benchmark
sysstat | → Hardware handling
systemd | → System tools
sysvinit | → System tools
taglib | → Libraries → Audio/Sound
tar | → Development tools
targetcli-fb | → Hardware handling
tcl | → Interpreter languages and scripting
tclap | → Libraries → Text and terminal handling
tcllib | → Interpreter languages and scripting → tcl libraries/modules
tcpdump | → Networking applications
tcping | → Networking applications
tcpreplay | → Networking applications
tftpd | → Networking applications
thrift | → Libraries → Networking
thttpd | → Networking applications
ti-gfx | → Hardware handling
ti-uim | → Hardware handling
ti-utils | → Hardware handling
tidsp-binaries | → Audio and video applications
tiff | → Libraries → Graphics
time | → Shell and utilities
tinyalsa | → Libraries → Audio/Sound
tinyhttpd | → Networking applications
tinymembench | → Debugging, profiling and benchmark
tinyxml | → Libraries → JSON/XML
tmux | → Shell and utilities
tn5250 | → Networking applications
torsmo | → Graphic libraries and applications (graphic/text)
trace-cmd | → Debugging, profiling and benchmark
transmission | → Networking applications
tree | → Development tools
tremor (fixed point vorbis decoder) | → Libraries → Audio/Sound
trinity | → Debugging, profiling and benchmark
tslib | → Libraries → Hardware handling
tstools | → Audio and video applications
tvheadend | → Networking applications
twm | → Graphic libraries and applications (graphic/text) → X11R7 Applications
twolame | → Audio and video applications
u-boot tools | → Hardware handling
udisks | → Hardware handling
udpcast | → Networking applications
uemacs | → Text editors and viewers
ulogd | → Networking applications
unionfs (FUSE) | → Filesystem and flash utilities
upmpdcli | → Audio and video applications
urg | → Libraries → Hardware handling
usb_modeswitch | → Hardware handling
usb_modeswitch_data | → Hardware handling
usbmount | → Hardware handling
usbredir | → Libraries → Networking
usbutils | → Hardware handling
ushare | → Networking applications
ussp-push | → Networking applications
util-linux | → System tools
util-macros | → Graphic libraries and applications (graphic/text) → X11R7 Utilities
ux500-firmware | → Hardware handling → Firmware
valgrind | → Debugging, profiling and benchmark
vde2 | → Networking applications
videoproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
viewres | → Graphic libraries and applications (graphic/text) → X11R7 Applications
vim | → Text editors and viewers
vlc | → Audio and video applications
vo-aacenc | → Libraries → Audio/Sound
vorbis-tools | → Audio and video applications
vpnc | → Networking applications
vsftpd | → Networking applications
vtun | → Networking applications
w_scan | → Hardware handling
wavpack | → Audio and video applications
wayland | → Libraries → Graphics
webkit | → Libraries → Graphics
WebKit Module | → Graphic libraries and applications (graphic/text)
webp | → Libraries → Graphics
webrtc-audio-processing | → Libraries → Audio/Sound
weston | → Graphic libraries and applications (graphic/text)
wget | → Networking applications
whetstone | → Debugging, profiling and benchmark
which | → Shell and utilities
whois | → Networking applications
windowswmproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
wipe | → Hardware handling
wireless tools | → Networking applications
wireless-regdb | → Networking applications
wireshark | → Networking applications
wmctrl | → Graphic libraries and applications (graphic/text)
wpa_supplicant | → Networking applications
wsapi | → Interpreter languages and scripting → Lua libraries/modules
wvdial | → Networking applications
wvstreams | → Libraries → Networking
x11perf | → Graphic libraries and applications (graphic/text) → X11R7 Applications
x11vnc | → Graphic libraries and applications (graphic/text)
x264 | → Libraries → Multimedia
xauth | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xavante | → Interpreter languages and scripting → Lua libraries/modules
xbacklight | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xbiff | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xbitmaps | → Graphic libraries and applications (graphic/text) → X11R7 Other data
xbmc | → Audio and video applications
xbmc-addon-xvdr | → Audio and video applications
xbmc-pvr-addons | → Audio and video applications
xcalc | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xcb-proto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xcb-util | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
xcb-util-image | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
xcb-util-keysyms | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
xcb-util-wm | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
xclipboard | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xclock | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xcmiscproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xcmsdb | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xconsole | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xcursor-transparent-theme | → Graphic libraries and applications (graphic/text) → X11R7 Other data
xcursorgen | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xdata_xcursor-themes | → Graphic libraries and applications (graphic/text) → X11R7 Other data
xdbedizzy | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xditview | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xdm | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xdpyinfo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xdriinfo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xedit | → Graphic libraries and applications (graphic/text) → X11R7 Applications
Xenomai Userspace | → Real-Time
xerces-c++ | → Libraries → JSON/XML
xev | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xextproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xeyes | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xf86-input-evdev | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-joystick | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-keyboard | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-mouse | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-synaptics | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-tslib | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-vmmouse | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-input-void | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-ark | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-ast | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-ati | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-cirrus | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-dummy | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-fbdev | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-geode | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-glide | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-glint | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-i128 | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-intel | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-mach64 | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-mga | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-neomagic | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-nv | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-openchrome | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-r128 | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-savage | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-siliconmotion | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-sis | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-tdfx | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-tga | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-trident | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-v4l | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-vesa | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-vmware | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-voodoo | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86-video-wsfb | → Graphic libraries and applications (graphic/text) → X11R7 Drivers
xf86bigfontproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xf86dga | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xf86dgaproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xf86driproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xf86vidmodeproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xfd | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xfontsel | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xfs | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xfsinfo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xfsprogs | → Filesystem and flash utilities
xgamma | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xgc | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xhost | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xineramaproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xinetd | → Networking applications
xinit | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xinput | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xinput-calibrator | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xkbcomp | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xkbevd | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xkbprint | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xkbutils | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xkeyboard-config | → Graphic libraries and applications (graphic/text)
xkill | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xl2tp | → Networking applications
xload | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xlogo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xlsatoms | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xlsclients | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xlsfonts | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xmag | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xman | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xmessage | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xmh | → Graphic libraries and applications (graphic/text) → X11R7 Applications
XML Patterns Module | → Graphic libraries and applications (graphic/text)
xmlstarlet | → Shell and utilities
xmodmap | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xmore | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xorg-server | → Graphic libraries and applications (graphic/text) → X11R7 Servers
xpr | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xprop | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xproto | → Graphic libraries and applications (graphic/text) → X11R7 X protocols
xrandr | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xrdb | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xrefresh | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xscreensaver | → Graphic libraries and applications (graphic/text)
xset | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xsetmode | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xsetpointer | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xsetroot | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xsm | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xstdcmap | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xterm | → Graphic libraries and applications (graphic/text)
xtrans | → Graphic libraries and applications (graphic/text) → X11R7 Libraries
xvidtune | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xvinfo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xvkbd | → Graphic libraries and applications (graphic/text)
xwd | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xwininfo | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xwud | → Graphic libraries and applications (graphic/text) → X11R7 Applications
xz-utils | → Compressors and decompressors
yajl | → Libraries → JSON/XML
yaml-cpp | → Libraries → JSON/XML
yasm | → Development tools
yavta | → Audio and video applications
ympd | → Audio and video applications
zd1211-firmware | → Hardware handling → Firmware
zeromq | → Libraries → Networking
zlib | → Libraries → Compression and decompression
zlog | → Libraries → Logging
zmqpp | → Libraries → Networking
znc | → Networking applications
zsh | → Shell and utilities
zxing | → Libraries → Graphics
zyre | → Libraries → Networking

## Chapter 25. List of virtual packages

These are the virtual packages known to `Buildroot`, with the corresponding symbols and providers.

Virtual packages | Symbols | Providers
--- | --- | ---
cryptodev | `BR2_PACKAGE_HAS_CRYPTODEV` | cryptodev-linux, ocf-linux
jpeg | `BR2_PACKAGE_HAS_JPEG` | jpeg, jpeg-turbo
libegl | `BR2_PACKAGE_HAS_LIBEGL` | mesa3d (w/ OpenGL EGL), gpu-viv-bin-mx6q, rpi-userland, sunxi-mali, ti-gfx
libgl | `BR2_PACKAGE_HAS_LIBGL` | mesa3d (w/ DRI swrast driver), mesa3d (w/ DRI i915 driver), mesa3d (w/ DRI i965 driver), mesa3d (w/ DRI radeon driver)
libgles | `BR2_PACKAGE_HAS_LIBGLES` | mesa3d (w/ OpenGL ES), gpu-viv-bin-mx6q, rpi-userland, sunxi-mali, ti-gfx
libopenmax | `BR2_PACKAGE_HAS_LIBOPENMAX` | bellagio, rpi-userland
libopenvg | `BR2_PACKAGE_HAS_LIBOPENVG` | gpu-viv-bin-mx6q, rpi-userland
luainterpreter | `BR2_PACKAGE_HAS_LUAINTERPRETER` | lua, luajit
powervr | `BR2_PACKAGE_HAS_POWERVR` | ti-gfx
udev | `BR2_PACKAGE_HAS_UDEV` | eudev, systemd

## Chapter 26. List of host utilities available in Buildroot

The following packages are all available in the menu `Host utilities`.

Packages
host cramfs
host dfu-util
host dos2unix
host dosfstools
host e2fsprogs
host genext2fs
host genimage
host genpart
host lpc3250loader
host mtd, jffs2 and ubi/ubifs tools
host mtools
host omap-u-boot-utils
host openocd
host parted
host patchelf
host pwgen
host sam-ba
host squashfs
host sunxi-tools
host u-boot tools
host util-linux
host-e2tools

## Chapter 27. Deprecated features

The following features are marked as deprecated in Buildroot due to them being either too old or unmaintained. They will be removed at some point, so stop using them. Each deprecated symbol in kconfig depends on a symbol `BR2_DEPRECATED_SINCE_xxxx_xx`, which provides an indication of when the feature can be removed: features will not be removed within the year following deprecation. For example, a symbol depending on `BR2_DEPRECATED_SINCE_2013_05` can be removed from 2014.05 onwards.

Features | Location
--- | ---
AVR32 | Target options → Target Architecture
mips I (generic) | Target options → Target Architecture Variant
mips II | Target options → Target Architecture Variant
mips III | Target options → Target Architecture Variant
mips IV | Target options → Target Architecture Variant
sstrip | Build options → strip command for binaries on target
Linux 3.0.x kernel headers | Toolchain → Kernel Headers
Linux 3.11.x kernel headers | Toolchain → Kernel Headers
Linux 3.13.x kernel headers | Toolchain → Kernel Headers
Linux 3.15.x kernel headers | Toolchain → Kernel Headers
Enable Objective-C support | Toolchain
Enable Fortran support | Toolchain
Xilinx Little Endian Microblaze GNU Tools 14.3 | Toolchain → Toolchain
Xilinx Little Endian Microblaze GNU Tools v2 | Toolchain → Toolchain
Xilinx Big Endian Microblaze GNU Tools | Toolchain → Toolchain
Xilinx Big Endian Microblaze GNU Tools | Toolchain → Toolchain
bison | Target packages → Development tools
distcc | Target packages → Development tools
Install flex binary on target | Target packages → Development tools
m4 | Target packages → Development tools
gob2 | Target packages → Graphic libraries and applications (graphic/text)
blackbox | Target packages → Graphic libraries and applications (graphic/text)
v 0.8.x | Target packages → Interpreter languages and scripting → Haserl version
Custom Network Settings | Bootloaders