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Luis Chamberlain ad9f64cd2d LICENSES: Add the copyleft-next-0.3.1 license Add the full text of the copyleft-next-0.3.1 license to the kernel tree as well as the required tags for reference and tooling. The license text was copied directly from the copyleft-next project's git tree [0]. Discussion of using copyleft-next-0.3.1 on Linux started since June, 2016 [1]. In the end Linus' preference was to have drivers use MODULE_LICENSE("GPL") to make it clear that the GPL applies when it comes to Linux [2]. Additionally, even though copyleft-next-0.3.1 has been found to be to be GPLv2 compatible by three attorneys at SUSE and Redhat [3], to err on the side of caution we simply recommend to always use the "OR" language for this license [4]. Even though it has been a goal of the project to be GPL-v2 compatible to be certain in 2016 I asked for a clarification about what makes copyleft-next GPLv2 compatible and also asked for a summary of benefits. This prompted some small minor changes to make compatibility even further clear and as of copyleft 0.3.1 compatibility should be crystal clear [5]. The summary of why copyleft-next 0.3.1 is compatible with GPLv2 is explained as follows: Like GPLv2, copyleft-next requires distribution of derivative works ("Derived Works" in copyleft-next 0.3.x) to be under the same license. Ordinarily this would make the two licenses incompatible. However, copyleft-next 0.3.1 says: "If the Derived Work includes material licensed under the GPL, You may instead license the Derived Work under the GPL." "GPL" is defined to include GPLv2. In practice this means copyleft-next code in Linux may be licensed under the GPL2, however there are additional obvious gains for bringing contributions from Linux outbound where copyleft-next is preferred. A summary of benefits why projects outside of Linux might prefer to use copyleft-next >= 0.3.1 over GPLv2: o It is much shorter and simpler o It has an explicit patent license grant, unlike GPLv2 o Its notice preservation conditions are clearer o More free software/open source licenses are compatible with it (via section 4) o The source code requirement triggered by binary distribution is much simpler in a procedural sense o Recipients potentially have a contract claim against distributors who are noncompliant with the source code requirement o There is a built-in inbound=outbound policy for upstream contributions (cf. Apache License 2.0 section 5) o There are disincentives to engage in the controversial practice of copyleft/ proprietary dual-licensing o In 15 years copyleft expires, which can be advantageous for legacy code o There are explicit disincentives to bringing patent infringement claims accusing the licensed work of infringement (see 10b) o There is a cure period for licensees who are not compliant with the license (there is no cure opportunity in GPLv2) o copyleft-next has a 'built-in or-later' provision The first driver submission to Linux under this dual strategy was lib/test_sysctl.c through commit `9308f2f9e7` ("test_sysctl: add dedicated proc sysctl test driver") merged in July 2017. Shortly after that I also added test_kmod through commit `d9c6a72d6f` ("kmod: add test driver to stress test the module loader") in the same month. These two drivers went in just a few months before the SPDX license practice kicked in. In 2018 Kuno Woudt went through the process to get SPDX identifiers for copyleft-next [6] [7]. Although there are SPDX tags for copyleft-next-0.3.0, we only document use in Linux starting from copyleft-next-0.3.1 which makes GPLv2 compatibility crystal clear. This patch will let us update the two Linux selftest drivers in subsequent patches with their respective SPDX license identifiers and let us remove repetitive license boiler plate. [0] https://github.com/copyleft-next/copyleft-next/blob/master/Releases/copyleft-next-0.3.1 [1] https://lore.kernel.org/lkml/1465929311-13509-1-git-send-email-mcgrof@kernel.org/ [2] https://lore.kernel.org/lkml/CA+55aFyhxcvD+q7tp+-yrSFDKfR0mOHgyEAe=f_94aKLsOu0Og@mail.gmail.com/ [3] https://lore.kernel.org/lkml/20170516232702.GL17314@wotan.suse.de/ [4] https://lkml.kernel.org/r/1495234558.7848.122.camel@linux.intel.com [5] https://lists.fedorahosted.org/archives/list/copyleft-next@lists.fedorahosted.org/thread/JTGV56DDADWGKU7ZKTZA4DLXTGTLNJ57/#SQMDIKBRAVDOCT4UVNOOCRGBN2UJIKHZ [6] https://spdx.org/licenses/copyleft-next-0.3.0.html [7] https://spdx.org/licenses/copyleft-next-0.3.1.html Cc: Goldwyn Rodrigues <rgoldwyn@suse.com> Cc: Kuno Woudt <kuno@frob.nl> Cc: Richard Fontana <fontana@sharpeleven.org> Cc: copyleft-next@lists.fedorahosted.org Cc: Ciaran Farrell <Ciaran.Farrell@suse.com> Cc: Christopher De Nicolo <Christopher.DeNicolo@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thorsten Leemhuis <linux@leemhuis.info> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Tim Bird <tim.bird@sony.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2 years ago
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deprecated	LICENSES/deprecated: add Zlib license text	4 years ago
dual	LICENSES: Add the copyleft-next-0.3.1 license	2 years ago
exceptions	LICENSES: Add GCC runtime library exception text	5 years ago
preferred	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2 years ago