1<!--#include file="header.html" --> 2 3<p> 4<h3>BusyBox is licensed under the GNU General Public License, version 2</h3> 5 6<p>BusyBox is licensed under <a href="http://www.gnu.org/licenses/gpl.html#SEC1">the 7GNU General Public License</a> version 2, which is often abbreviated as GPLv2. 8(This is the same license the Linux kernel is under, so you may be somewhat 9familiar with it by now.)</p> 10 11<p>A complete copy of the license text is included in the file LICENSE in 12the BusyBox source code.</p> 13 14<p><a href="/products.html">Anyone thinking of shipping BusyBox as part of a 15product</a> should be familiar with the licensing terms under which they are 16allowed to use and distribute BusyBox. Read the full test of the GPL (either 17through the above link, or in the file LICENSE in the busybox tarball), and 18also read the <a href="http://www.gnu.org/licenses/gpl-faq.html">Frequently 19Asked Questions about the GPL</a>.</p> 20 21<p>Basically, if you distribute GPL software the license requires that you also 22distribute the source code to that GPL-licensed software. So if you distribute 23BusyBox without making the source code to the version you distribute available, 24you violate the license terms, and thus infringe on the copyrights of BusyBox. 25(This requirement applies whether or not you modified BusyBox; either way the 26license terms still apply to you.) Read the license text for the details.</p> 27 28<h3>A note on GPL versions</h3> 29 30<p>Version 2 of the GPL is the only version of the GPL which current versions 31of BusyBox may be distributed under. New code added to the tree is licensed 32GPL version 2, and the project's license is GPL version 2.</p> 33 34<p>Older versions of BusyBox (versions 1.2.2 and earlier, up through about svn 3516112) included variants of the recommended "GPL version 2 or (at your option) 36later versions" boilerplate permission grant. Ancient versions of BusyBox 37(before svn 49) did not specify any version at all, and section 9 of GPLv2 38(the most recent version at the time) says those old versions may be 39redistributed under any version of GPL (including the obsolete V1). This was 40conceptually similar to a dual license, except that the different licenses were 41different versions of the GPL.</p> 42 43<p>However, BusyBox has apparently always contained chunks of code that were 44licensed under GPL version 2 only. Examples include applets written by Linus 45Torvalds (util-linux/mkfs_minix.c and util_linux/mkswap.c) which stated they 46"may be redistributed as per the Linux copyright" (which Linus clarified in the 472.4.0-pre8 release announcement in 2000 was GPLv2 only), and Linux kernel code 48copied into libbb/loop.c (after Linus's announcement). There are probably 49more, because all we used to check was that the code was GPL, not which 50version. (Before the GPLv3 draft proceedings in 2006, it was a purely 51theoretical issue that didn't come up much.)</p> 52 53<p>To summarize: every version of BusyBox may be distributed under the terms of 54GPL version 2. New versions (after 1.2.2) may <b>only</b> be distributed under 55GPLv2, not under other versions of the GPL. Older versions of BusyBox might 56(or might not) be distributable under other versions of the GPL. If you 57want to use a GPL version other than 2, you should start with one of the old 58versions such as release 1.2.2 or SVN 16112, and do your own homework to 59identify and remove any code that can't be licensed under the GPL version you 60want to use. New development is all GPLv2.</p> 61 62<h3>License enforcement</h3> 63 64<p>BusyBox's copyrights are enforced by the <a 65href="http://www.softwarefreedom.org">Software Freedom Law Center</a> 66(you can contact them at gpl@busybox.net), which 67"accepts primary responsibility for enforcement of US copyrights on the 68software... and coordinates international copyright enforcement efforts for 69such works as necessary." If you distribute BusyBox in a way that doesn't 70comply with the terms of the license BusyBox is distributed under, expect to 71hear from these guys. Their entire reason for existing is to do pro-bono 72legal work for free/open source software projects. (We used to list people who 73violate the BusyBox license in <a href="/shame.html">The Hall of Shame</a>, 74but these days we find it much more effective to hand them over to the 75lawyers.)</p> 76 77<p>Our enforcement efforts are aimed at bringing people into compliance with 78the BusyBox license. Open source software is under a different license from 79proprietary software, but if you violate that license you're still a software 80pirate and the law gives the vendor (us) some big sticks to play with. We 81don't want monetary awards, injunctions, or to generate bad PR for a company, 82unless that's the only way to get somebody that repeatedly ignores us to comply 83with the license on our code.</p> 84 85<h3>A Good Example</h3> 86 87<p>These days, <a href="http://www.linksys.com/">Linksys</a> is 88doing a good job at complying with the GPL, they get to be an 89example of how to do things right. Please take a moment and 90check out what they do with 91<a href="http://www.linksys.com/servlet/Satellite?c=L_Content_C1&childpagename=US%2FLayout&cid=1115416836002&pagename=Linksys%2FCommon%2FVisitorWrapper"> 92distributing the firmware for their WRT54G Router.</a> 93Following their example would be a fine way to ensure that you 94have also fulfilled your licensing obligations.</p> 95 96<!--#include file="footer.html" --> 97