[821] | 1 | <!--#include file="header.html" -->
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| 2 |
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| 3 | <p>
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[1765] | 4 | <h3>BusyBox is licensed under the GNU General Public License, version 2</h3>
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[821] | 5 |
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| 6 | <p>BusyBox is licensed under <a href="http://www.gnu.org/licenses/gpl.html#SEC1">the
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[1765] | 7 | GNU General Public License</a> version 2, which is often abbreviated as GPLv2.
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| 8 | (This is the same license the Linux kernel is under, so you may be somewhat
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| 9 | familiar with it by now.)</p>
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[821] | 10 |
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[1765] | 11 | <p>A complete copy of the license text is included in the file LICENSE in
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| 12 | the BusyBox source code.</p>
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| 13 |
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[821] | 14 | <p><a href="/products.html">Anyone thinking of shipping BusyBox as part of a
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| 15 | product</a> should be familiar with the licensing terms under which they are
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| 16 | allowed to use and distribute BusyBox. Read the full test of the GPL (either
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| 17 | through the above link, or in the file LICENSE in the busybox tarball), and
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| 18 | also read the <a href="http://www.gnu.org/licenses/gpl-faq.html">Frequently
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| 19 | Asked Questions about the GPL</a>.</p>
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| 20 |
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| 21 | <p>Basically, if you distribute GPL software the license requires that you also
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| 22 | distribute the source code to that GPL-licensed software. So if you distribute
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| 23 | BusyBox without making the source code to the version you distribute available,
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| 24 | you violate the license terms, and thus infringe on the copyrights of BusyBox.
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| 25 | (This requirement applies whether or not you modified BusyBox; either way the
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| 26 | license terms still apply to you.) Read the license text for the details.</p>
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| 27 |
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[1765] | 28 | <h3>A note on GPL versions</h3>
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| 29 |
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| 30 | <p>Version 2 of the GPL is the only version of the GPL which current versions
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| 31 | of BusyBox may be distributed under. New code added to the tree is licensed
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| 32 | GPL version 2, and the project's license is GPL version 2.</p>
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| 33 |
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| 34 | <p>Older versions of BusyBox (versions 1.2.2 and earlier, up through about svn
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| 35 | 16112) included variants of the recommended "GPL version 2 or (at your option)
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| 36 | later versions" boilerplate permission grant. Ancient versions of BusyBox
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| 37 | (before svn 49) did not specify any version at all, and section 9 of GPLv2
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| 38 | (the most recent version at the time) says those old versions may be
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| 39 | redistributed under any version of GPL (including the obsolete V1). This was
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| 40 | conceptually similar to a dual license, except that the different licenses were
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| 41 | different versions of the GPL.</p>
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| 42 |
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| 43 | <p>However, BusyBox has apparently always contained chunks of code that were
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| 44 | licensed under GPL version 2 only. Examples include applets written by Linus
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| 45 | Torvalds (util-linux/mkfs_minix.c and util_linux/mkswap.c) which stated they
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| 46 | "may be redistributed as per the Linux copyright" (which Linus clarified in the
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| 47 | 2.4.0-pre8 release announcement in 2000 was GPLv2 only), and Linux kernel code
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| 48 | copied into libbb/loop.c (after Linus's announcement). There are probably
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| 49 | more, because all we used to check was that the code was GPL, not which
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| 50 | version. (Before the GPLv3 draft proceedings in 2006, it was a purely
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| 51 | theoretical issue that didn't come up much.)</p>
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| 52 |
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| 53 | <p>To summarize: every version of BusyBox may be distributed under the terms of
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| 54 | GPL version 2. New versions (after 1.2.2) may <b>only</b> be distributed under
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| 55 | GPLv2, not under other versions of the GPL. Older versions of BusyBox might
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| 56 | (or might not) be distributable under other versions of the GPL. If you
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| 57 | want to use a GPL version other than 2, you should start with one of the old
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| 58 | versions such as release 1.2.2 or SVN 16112, and do your own homework to
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| 59 | identify and remove any code that can't be licensed under the GPL version you
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| 60 | want to use. New development is all GPLv2.</p>
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| 61 |
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| 62 | <h3>License enforcement</h3>
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| 63 |
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[821] | 64 | <p>BusyBox's copyrights are enforced by the <a
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[1765] | 65 | href="http://www.softwarefreedom.org">Software Freedom Law Center</a>
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| 66 | (you can contact them at gpl@busybox.net), which
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[821] | 67 | "accepts primary responsibility for enforcement of US copyrights on the
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| 68 | software... and coordinates international copyright enforcement efforts for
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| 69 | such works as necessary." If you distribute BusyBox in a way that doesn't
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| 70 | comply with the terms of the license BusyBox is distributed under, expect to
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| 71 | hear from these guys. Their entire reason for existing is to do pro-bono
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| 72 | legal work for free/open source software projects. (We used to list people who
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| 73 | violate the BusyBox license in <a href="/shame.html">The Hall of Shame</a>,
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| 74 | but these days we find it much more effective to hand them over to the
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| 75 | lawyers.)</p>
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| 76 |
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| 77 | <p>Our enforcement efforts are aimed at bringing people into compliance with
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| 78 | the BusyBox license. Open source software is under a different license from
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| 79 | proprietary software, but if you violate that license you're still a software
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| 80 | pirate and the law gives the vendor (us) some big sticks to play with. We
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| 81 | don't want monetary awards, injunctions, or to generate bad PR for a company,
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| 82 | unless that's the only way to get somebody that repeatedly ignores us to comply
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| 83 | with the license on our code.</p>
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| 84 |
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| 85 | <h3>A Good Example</h3>
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| 86 |
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| 87 | <p>These days, <a href="http://www.linksys.com/">Linksys</a> is
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| 88 | doing a good job at complying with the GPL, they get to be an
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| 89 | example of how to do things right. Please take a moment and
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| 90 | check out what they do with
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| 91 | <a href="http://www.linksys.com/servlet/Satellite?c=L_Content_C1&childpagename=US%2FLayout&cid=1115416836002&pagename=Linksys%2FCommon%2FVisitorWrapper">
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| 92 | distributing the firmware for their WRT54G Router.</a>
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| 93 | Following their example would be a fine way to ensure that you
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| 94 | have also fulfilled your licensing obligations.</p>
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| 95 |
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| 96 | <!--#include file="footer.html" -->
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| 97 |
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