Buildroot

Buildroot is a nice, simple, and efficient embedded Linux build system.

Important links

 * Buildroot main page
 * Bug tracker
 * Autobuilders results
 * Project patchwork
 * The reproducible builds work
 * The top-level parallel build work
 * Security Vulnerability Management
 * Language package managers and downloading dependencies (go mod, cargo, php compose)

Developer days
Upcoming:
 * Buildroot Developer Days, 6-8 February 2023, Brussels, Belgium, after FOSDEM

Past:
 * Buildroot Developer Days, 17-18 September 2022, Dublin, Ireland, after ELCE
 * Virtual Buildroot Developer Days, July 27, August 28, August 29, 2020
 * Buildroot Developer Days, 3-5 February 2020, Brussels, Belgium, after FOSDEM
 * Buildroot Developer Days, 25-27 October 2019, Lyon, France, before ELCE
 * Buildroot Developer Days, 4-6 February 2019, Brussels, Belgium, after FOSDEM
 * Buildroot Developer Days, 20-21 October 2018, Edinburgh, UK, before ELCE
 * Buildroot Developer Days, 5-6 February 2018, Brussels, Belgium, after FOSDEM
 * Buildroot Developer Days, 21-22 October 2017, Prague, Czech Republic, before ELCE.
 * Buildroot Developer Days, 6-7 February 2017, Brussels, Belgium, after FOSDEM
 * Buildroot Developer Days, 14-16 October 2016, Berlin, Germany, after ELCE.
 * Buildroot Developer Days, 1-2 February 2016, Brussels, Belgium, after FOSDEM
 * Buildroot Developer Days, 3-4 October 2015, Dublin, Ireland, before ELC-E (report).
 * Buildroot Developer Days, 2-3 February 2015, Brussels, Belgium, after FOSDEM.
 * Buildroot Developer Days, 11-12 October 2014, Düsseldorf, Germany, before ELC-E.
 * Buildroot Developer Days, 3-4 February 2014, Brussels, Belgium, after FOSDEM.
 * Buildroot Developer Days, 26-27 October 2013, Edinburgh UK, after ELC-E.
 * Buildroot Developer Days, 4-5 February 2013, Brussels Belgium, after FOSDEM.
 * Buildroot Developer Days, 3-4 November 2012, Barcelona Spain, before ELC-E.
 * Buildroot Developer Days, 3 February 2012, Brussels Belgium, before FOSDEM (report)
 * Buildroot Developer Days, 29 October 2011, Prague, Czech Republic, after ELCE (report)

Talks
This section gathers the list of talks given about Buildroot, as well as the slides and video when available.

Past:
 * Buildroot: What's New?, Thomas Petazzoni, Embedded Linux Conference, 12-14 March, Portland, Oregon. Slides, Video.
 * Buildroot: What's New?, Thomas Petazzoni, Embedded Linux Conference Europe, 23-25 October, Prague, Czech Republic. Slides, Video.
 * Buildroot: Making Embedded Linux Easy? A Real-Life Example, Yann E. MORIN, Embedded Linux Conference Europe, 23-25 October, Prague, Czech Republic. Slides, Video.
 * Tutorial: Learning the Basics of Buildroot, Thomas Petazzoni, Embedded Linux Conference Europe, October 5 - 7, 2015, Dublin, Ireland. Slides, Video.
 * "Buildroot: a deep dive into the core", Thomas Petazzoni, Embedded Linux Conference Europe, 13-15 October 2014, Düsseldorf, Germany. Slides.
 * Buildroot: what's new, Thomas Petazzoni, Embedded Linux Conference, 1 May 2014, San Jose, United States. Slides, HD video, Low-res video, Audio only
 * "Buildroot: what is new", Peter Korsgaard, Embedded Linux Conference Europe, 25 October 2013, Edinburgh, UK. Slides, Video.

List of forks

 * SkiffOS is a modular config layering system for Buildroot with support for 50+ targets.
 * Batocera.linux is an open-source and completely free retro-gaming distribution.
 * Home Assistant Operating System. Home Assistant Operating System (formerly HassOS) is an operating system optimized for hosting Home Assistant and its Add-ons.
 * OpenIL. OpenIL is an open source project based on Buildroot and designed for embedded industrial solution.
 * Bsquask SDK. A Rasberry-Pi related fork.
 * buildroot-rpi. Another RPi related fork, with a lot of focus on Qt5 and GStreamer (appears to be defunct).
 * Buildroot Submodule. Not a fork, but a convenience layer on top of buildroot.
 * Experimental 'shell' around Buildroot. Another wrapper around Buildroot, to help manage projects.

Todo list
This is a list of improvements that we would like to see in buildroot. Feel free to add suggestions here. If you're working on one of these items, put your name and the date behind it, to avoid duplicate work.

There are a number of patches that have been determined to be useful but for various reasons nobody currently has time to review or test them. Anybody, especially a person new to buildroot, is welcome to adopt these patches and resubmit them to the mailing list.

Perpetual work
Some jobs are never finished. When you have a bit of uninterrupted time you would like to spend on Buildroot, you can pick one of these things.

Autobuild failures
The autobuild failures are random configurations for which the build fails. This is what we want to fix. A summary of failures is sent daily to the mailing list, this gives a good summary of the most frequently failing packages.


 * Go to the failing output ("end log" link) and see if it's an error message that you can make sense of. Often you can't, then just skip it and look for something else.
 * Check on patchwork if a fix was already posted. Also check in recent commit history if a fix was already committed. Also ask on IRC if someone is working on it.
 * Reproduce the issue with the br-reproduce-build script. However, it is often easier to first attempt to reproduce it by simply downloading the defconfig as, run  , then  . Not all issues can be reproduced this way however! Also, if the failing configuration was using a Buildroot toolchain rather than an external toolchain, it can be worth to first try to reproduce with an external toolchain (which reduces the build time by quite a lot).
 * Produce a fix. Here are some hints.
 * Perhaps the package simply doesn't support that configuration (target architecture, libc type, static build, threads, GCC version) and a dependency has to be added in Config.in.
 * Sometimes a fix was already found by someone else and sent upstream, so check its bugs list, pull requests and recent commits. Also check if OpenEmbedded has a fix already.
 * Sometimes a similar issue was recently fixed for another package, so you can.
 * Test the fix with the actual configuration (so no switching to external toolchain any more). Do a full clean build.
 * Check your changes with the  script.
 * Post your fix according to the contribution guidelines in the manual.

See this commit for an example of what the commit message should look like. Important is to have:
 * the compilation error;
 * the Fixes: line;
 * your Signed-off-by.

Update CVE exceptions
Buildroot keeps track of which CVEs apply to each package, based on a CPE ID. However, many CVEs don't actually apply. In particular very old CVEs are likely not to be applicable to the version currently shipped in Buildroot.


 * Look at the package statistics. Sort by "CVEs". Look for a package with old CVEs.
 * For each CVE, check if it really applies.
 * If not, update the package's  with the CVE to ignore. Commit with a commit message that explains in detail why the CVE can be ignored. Example commit message.
 * If the CVE really applies, check if there is an upstream patch fixing it.
 * Check your changes with the  script.
 * Post your fix according to the contribution guidelines in the manual.

Packages
'''Note: if you start working on any of these packages, please edit this section to indicate it. If the package is proposed in a bug report, please also update the bug report. Sending a mail to the mailing list also never hurts, you never know that someone else started working on it without following this guideline.'''

Important

 * Instead of building the Go compiler, add support for using a pre-compiled Go compiler, like we do for Rust
 * Instead of building host-nodejs, add support for using a pre-compiled NodeJS for the host
 * Improve the imx-gpu-viv package to not install everything. See https://lore.kernel.org/buildroot/20210805233615.4e69d63d@windsurf/T/#u

Nice to have

 * Extend support/scripts/setlocalversion to include the git/hg version(s) of BR2_EXTERNAL.
 * Create a package for the Qt5 demo/benchmark application at https://github.com/prabindh/xgxperf.
 * Packages proposed in bug reports (often with patch)
 * openvz https://bugs.busybox.net/show_bug.cgi?id=405
 * rdiff-backup https://bugs.busybox.net/show_bug.cgi?id=1309 [Shaym Saini  is working on this]
 * wxWidgets https://bugs.busybox.net/show_bug.cgi?id=261
 * Create a package for UnixBench benchmark suite at https://github.com/kdlucas/byte-unixbench.
 * uwsgi => Adam Duskett pending patch series: https://patchwork.ozlabs.org/project/buildroot/list/?series=144709&state=%2A&archive=both

Toolchain

 * Add the support for the x86-64 x32 capable toolchain. See http://patchwork.ozlabs.org/patch/561904/
 * Add the support for the Aarch64 ilp32 capable toolchain (for now the gcc/binutils/glibc upstream support is not ready yet). See http://lists.busybox.net/pipermail/buildroot/2015-August/137356.html, http://patchwork.ozlabs.org/patch/506803/, http://patchwork.ozlabs.org/patch/506800/, http://patchwork.ozlabs.org/patch/506801/

Documentation

 * Convert the documentation + the generation workflow from current asciidoc to either markdown or ReStructuredText (people are nowadays more used to that syntax, and they are formatted directly when viewed in gitlab/github).
 * Document how to contribute (how often to repost, what to expect, ...) basic guide
 * Document that package patches should be sent upstream

Core Buildroot infrastructure

 * Cargo and Go post-process handling for vendoring
 * Add support for tarball formats other than gz


 * Cargo post-process handling for vendoring
 * Either replace "cargo install" by manual installation of files, or ensure that "cargo install" doesn't rebuild things. See https://lore.kernel.org/buildroot/20220106210000.397694-1-thomas.petazzoni@bootlin.com/T/#m2fe31f718c45675f7fb52d001e75cc0386db8aee
 * Use more environment variables when calling cargo, to avoid using a cargo configuration file. See https://lore.kernel.org/buildroot/20220106210000.397694-1-thomas.petazzoni@bootlin.com/T/#m8dc0e19638fc1f2c36cac7bba5de615a2a671dc1


 * Investigate adding support for ICECC. See also https://www.pengutronix.de/en/2018-09-13-fixing-icecc.html.


 * Several improvements are possible in the download infrastructure (even after all the improvements that were already done):
 * Rename the downloaded files so they include the package name and version. Special care has to be taken for primary and secondary sites, and for extra downloads (including patches).
 * Split between FOO_SITE and FOO_SOURCE shouldn't be necessary. Or it could be made optional, i.e. make it possible to specify the full path in FOO_SOURCE.


 * Locale handling is broken: it doesn't take into account the alias file when purging aliases. See this mail from patchwork cleanup #3 and this patch that also fixes a locale problem, but not everything. Tests for this are also required.


 * Add instrumentation scripts to analyse package installed files:
 * find libraries with wrong RPATH/RUNPATH tags
 * detect unused .so libs (eg. shared libs that are not DT_NEEDED by anything - note: only detect those libs, don't remove: can be used as plugin (dlopen), or used by an application built outside Buildroot)


 * A script that checks consistency of depends/select for packages. Maybe it can be integrated to the current check-package.


 * Security Hardening

Testing infrastructure

 * Fix run-tests to use a config file for download and output directories, can be overridden in the environment
 * Documentation on how to add a test, including naming convention

TODO items under discussion
Here are some nice-to-have's for which it is not entirely clear if and how they could be implemented:


 * Out-of-tree builds, which allows the package source to be shared between different output directories and between host and target compiles.
 * It would be nice if you could run a buildroot command that prepares a local copy of a package's source, and allows you to generate patches for it later. This could use git or quilt to keep track of the patches.
 * It would be nice if there was a make target to reinstall everything to the target (i.e. remove all the target-installed stamps, remove the root stamp, maybe remove the target too). However, what is missing is the copying of the toolchain support files (libc.so etc.).  It's not obvious that this can be done in a reliable way.
 * To facilitate debugging, all packages should be installed to the staging directory. The target directory should in fact be a subset of the staging directory. See the FOSDEM 2013 discussion at http://elinux.org/Buildroot:DeveloperDaysFOSDEM2013, and the discussion around patch http://patchwork.ozlabs.org/patch/252718/. This is however a significant change in Buildroot, so probably difficult to implement, and will raise a number of quite complicated questions.