1 | <!--#include file="header.html" -->
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2 |
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3 | <p>
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4 | <h3>BusyBox is licensed under the GNU General Public License, version 2</h3>
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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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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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10 |
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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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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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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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64 | <p>BusyBox's copyrights are enforced by the <a
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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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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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97 |
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