1 $NetBSD: licensing,v 1.4 2026/05/14 12:24:57 nia Exp $ 2 3 NetBSD Licensing 4 ================ 5 6 In an ideal world, the entire of NetBSD should be available under 7 simple permissive software licenses. The 2-clause BSD license is 8 recommended for new contributions. 9 10 Background: GPL in base 11 ----------------------- 12 13 In the 1990s, the BSD developers at CSRG realized their toolchain was 14 falling behind alternatives. One of the reasons for this was Sun 15 choosing to lock their compiler behind a paywall - as a result, Sun's 16 users went out in search of freeware alternatives. They found GNU's GCC, 17 and immediately formed a new community around improving it. 18 Eventually, various GNU tools found their way into BSD. 19 20 We would like to eliminate the use of the GNU General Public License 21 in the base system. This provides a number of advantages: less worrying 22 about license compatibility, easier sharing of code between NetBSD 23 components, less likelihood of being sued for redistributing NetBSD 24 binaries, less legalese and need for lawyers to interpret it, 25 and an overall reduction in GNU info pages. 26 27 As a general rule, most GPL code in NetBSD provides programs that 28 are "nice to have", but not fully essential for a working system, 29 so redistributors have an option to remove or replace them. 30 31 For example, some NetBSD ports can be built using Clang as the 32 toolchain instead of GCC (see mk.conf(5), HAVE_LLVM). 33 34 GPL code lives under the following directories to ensure clean 35 separation: 36 37 * src/external/gpl2 38 * src/external/gpl3 39 * src/sys/external/gpl2 40 41 Background: Advertising clause 42 ------------------------------ 43 44 At some point, Berkeley added the following clause to their license 45 for the free parts of BSD UNIX: 46 47 * 3. All advertising materials mentioning features or use of this software 48 * must display the following acknowledgement: 49 * This product includes software developed by [copyright holder]. 50 51 With time, this clause came to be seen as onerous: there is already 52 a requirement to credit copyright holders in the documentation of 53 redistributions, and it's very difficult to enforce. At various points, 54 distributing NetBSD required including hundreds of "This product 55 includes software developed [...]" statements. It also makes it more 56 complicated to include NetBSD code in projects under other licenses. 57 58 Berkeley removed the advertising clause in 1999, and clarified their 59 stance against including it in 2012. However, there are lots of 60 instances where it has been copy and pasted by other people and 61 organizations. Therefore, its removal from NetBSD is mostly a social 62 challenge. 63 64 Technical priorities 65 -------------------- 66 67 The directory under external/gpl2 contains several programs that 68 could be replaced. Most of them are quite old versions now, chosen 69 to avoid GPLv3: 70 71 * diffutils - Replaced with FreeBSD-derived diff(1). MKBSDDIFF is now 72 the default. 73 * grep - Could be replaced with FreeBSD grep(1). Someone needs to 74 compare the performance. Other grep implementations in C likely 75 exist. A MKBSDGREP option exists, but the copy is probably old. 76 * rcs - Supposedly OpenBSD developed a compatible replacement. 77 * xcvs - Priority for removal as we transition away from CVS. 78 * groff - Mostly replaced by mandoc(1), although some non-manual use 79 cases (e.g. distrib/notes) continue to rely on groff. Optional - 80 a MKGROFF option exists. Such files could also be converted to 81 plain text. 82 * send-pr - Part of our infrastructure, but basically optional - 83 alternatives like the gnats web interface exist. 84 * gawk - Needed only by other GNU software? 85 * gmake - Needed only by other GNU software. 86 * texinfo - Needed only by other GNU software. 87 88 The directory under sys/external/gpl2 mainly contains device tree 89 sources, providing platform definition files for embedded system 90 boards. Removing this would break a lot of platforms. 91 92 The directory under external/gpl3 only contains toolchain-relevant 93 files, and can be mostly avoided with HAVE_LLVM=yes and elftoolchain. 94 95 Social and legal tasks 96 ---------------------- 97 98 A list of advertising clauses that still apply can be found in: 99 100 src/distrib/notes/common/legal.common 101 102 This file should be kept in sync as copyright holders are contacted. 103 104 There are several high-priority targets for the removal of the 105 advertising clause: 106 107 * Lawrence Berkeley Laboratory advertising clauses are very widespread. 108 It is unclear whether Berkeley granted permission to remove such 109 clauses (FreeBSD apparently think so). Berkeley should be contacted 110 for clarification. 111 * Harvard University 4-clauses licenses are widespread, and it's 112 possible someone knows an insider who could accelerate the process 113 of getting permission to fix them. 114 * Wasabi Systems copyrights are very widespread in NetBSD. They were 115 "the NetBSD company" of their time. It is unclear who currently owns 116 Wasabi Systems' intellectual property. Someone should figure this out, 117 or we should use Foundation funds to acquire it. 118 * 4-clause BSD licenses are also found in the tree belonging to 119 Cisco (primarily in SCTP code). It's also possible someone knows an 120 insider who could accelerate the process. 121 122 Otherwise, the social and legal tasks mostly involve trying to find 123 old contributors' current email addresses, and asking them for 124 permission to relicense. This strategy has been somewhat successful, 125 and should be completed before doing so is no longer possible. 126
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