1// -*- mode:doc; -*- 2// vim: set syntax=asciidoc: 3 4[[legal-info]] 5 6== Legal notice and licensing 7 8=== Complying with open source licenses 9 10All of the end products of Buildroot (toolchain, root filesystem, kernel, 11bootloaders) contain open source software, released under various licenses. 12 13Using open source software gives you the freedom to build rich embedded 14systems, choosing from a wide range of packages, but also imposes some 15obligations that you must know and honour. 16Some licenses require you to publish the license text in the documentation of 17your product. Others require you to redistribute the source code of the 18software to those that receive your product. 19 20The exact requirements of each license are documented in each package, and 21it is your responsibility (or that of your legal office) to comply with those 22requirements. 23To make this easier for you, Buildroot can collect for you some material you 24will probably need. To produce this material, after you have configured 25Buildroot with +make menuconfig+, +make xconfig+ or +make gconfig+, run: 26 27-------------------- 28make legal-info 29-------------------- 30 31Buildroot will collect legally-relevant material in your output directory, 32under the +legal-info/+ subdirectory. 33There you will find: 34 35* A +README+ file, that summarizes the produced material and contains warnings 36 about material that Buildroot could not produce. 37* +buildroot.config+: this is the Buildroot configuration file that is usually 38 produced with +make menuconfig+, and which is necessary to reproduce the 39 build. 40* The source code for all packages; this is saved in the +sources/+ and 41 +host-sources/+ subdirectories for target and host packages respectively. 42 The source code for packages that set +<PKG>_REDISTRIBUTE = NO+ will not be 43 saved. 44 Patches that were applied are also saved, along with a file named +series+ 45 that lists the patches in the order they were applied. Patches are under the 46 same license as the files that they modify. 47 Note: Buildroot applies additional patches to Libtool scripts of 48 autotools-based packages. These patches can be found under 49 +support/libtool+ in the Buildroot source and, due to technical 50 limitations, are not saved with the package sources. You may need to 51 collect them manually. 52* A manifest file (one for host and one for target packages) listing the 53 configured packages, their version, license and related information. 54 Some of this information might not be defined in Buildroot; such items are 55 marked as "unknown". 56* The license texts of all packages, in the +licenses/+ and +host-licenses/+ 57 subdirectories for target and host packages respectively. 58 If the license file(s) are not defined in Buildroot, the file is not produced 59 and a warning in the +README+ indicates this. 60 61Please note that the aim of the +legal-info+ feature of Buildroot is to 62produce all the material that is somehow relevant for legal compliance with the 63package licenses. Buildroot does not try to produce the exact material that 64you must somehow make public. Certainly, more material is produced than is 65needed for a strict legal compliance. For example, it produces the source code 66for packages released under BSD-like licenses, that you are not required to 67redistribute in source form. 68 69Moreover, due to technical limitations, Buildroot does not produce some 70material that you will or may need, such as the toolchain source code for 71some of the external toolchains and the Buildroot source code itself. 72When you run +make legal-info+, Buildroot produces warnings in the +README+ 73file to inform you of relevant material that could not be saved. 74 75Finally, keep in mind that the output of +make legal-info+ is based on 76declarative statements in each of the packages recipes. The Buildroot 77developers try to do their best to keep those declarative statements as 78accurate as possible, to the best of their knowledge. However, it is very 79well possible that those declarative statements are not all fully accurate 80nor exhaustive. You (or your legal department) _have_ to check the output 81of +make legal-info+ before using it as your own compliance delivery. See 82the _NO WARRANTY_ clauses (clauses 11 and 12) in the +COPYING+ file at the 83root of the Buildroot distribution. 84 85[[legal-info-buildroot]] 86=== Complying with the Buildroot license 87 88Buildroot itself is an open source software, released under the 89http://www.gnu.org/licenses/old-licenses/gpl-2.0.html[GNU General 90Public License, version 2] or (at your option) any later version, with 91the exception of the package patches detailed below. 92However, being a build system, it is not normally part of the end product: 93if you develop the root filesystem, kernel, bootloader or toolchain for a 94device, the code of Buildroot is only present on the development machine, not 95in the device storage. 96 97Nevertheless, the general view of the Buildroot developers is that you should 98release the Buildroot source code along with the source code of other packages 99when releasing a product that contains GPL-licensed software. 100This is because the 101http://www.gnu.org/licenses/old-licenses/gpl-2.0.html[GNU GPL] 102defines the "'complete source code'" for an executable work as "'all the 103source code for all modules it contains, plus any associated interface 104definition files, plus the scripts used to control compilation and installation 105of the executable'". 106Buildroot is part of the 'scripts used to control compilation and 107installation of the executable', and as such it is considered part of the 108material that must be redistributed. 109 110Keep in mind that this is only the Buildroot developers' opinion, and you 111should consult your legal department or lawyer in case of any doubt. 112 113==== Patches to packages 114 115Buildroot also bundles patch files, which are applied to the sources 116of the various packages. Those patches are not covered by the license 117of Buildroot. Instead, they are covered by the license of the software 118to which the patches are applied. When said software is available 119under multiple licenses, the Buildroot patches are only provided under 120the publicly accessible licenses. 121 122See xref:patch-policy[] for the technical details. 123