Take the 2-minute tour ×
Programmers Stack Exchange is a question and answer site for professional programmers interested in conceptual questions about software development. It's 100% free, no registration required.

I saw a company is using BusyBox and also using Gpl + Lgpl + Mpl packages on it, and then they have there own application running on it. Their application is a closed source package.

You buy the device but its closed source. How come GPL mixed with LGPL+MPL becomes closed source?

I thought the rule is?? Or I am wrong or this following info is wrong?:

GPL: If you use it in your application then you must release your application under the GPL. That doesn't mean you can't also sell it (like they sell Linux CD's) but you must also release the source code for free. That might work for you, but probably not.

LGPL: If you use it in your application then you can still have a closed source proprietary licensed application. But if you modify the LGPL library then you must release your modifications under the LGPL, even though your application can remain closed source.

share|improve this question
First, BusyBox is a program, not a system. Second, BusyBox in particular has a great Busybox license page about this. And the rest is covered in the GPL FAQ. –  mctylr Dec 16 '11 at 19:22

4 Answers 4

up vote 6 down vote accepted

It is perfectly all right to sell an "aggregrate" of closed-source and open-source software according to the GPL FAQ. If the company compiled a Linux, built their own program on top of it using only LGPL libraries, and sold the resulting product while publishing all GPL/LGPL sources with it, they are not violating the GPL.

The point here is: The GPL does not extend to programs simply running on the same computer and communicating/interacting with the closed-source program. An open-source window manager like BusyBox is of course allowed to manage closed-source windows. As a rule of thumb, the GPL reaches as far as the address space of the licensed code.

share|improve this answer
That's pretty much what I was going so say, I was just going to add a note about tivoization too though. –  Mark Booth Dec 16 '11 at 15:33
@thiton: So what you are saying is example: fedoraproject.org/wiki/Licensing . I can copy this distro and re-distribute it with my own brand name, and let my new Bnome3 Desktop shows up when it boot is legal? (Where i have hundreds of GPL + LGPL + MPL tools mixed to let my Bnome3 Desktop run)? –  YumYumYum Dec 16 '11 at 15:46
@Google: Yes, but you need to distribute all the sources for the GPL parts with your distro. –  thiton Dec 16 '11 at 16:03
@Google: The GPL requires that derivative works carry 'prominent' notices that they are derivatives. (GPL Section 4 and 5). So, you could brand it as the Bnome3 Desktop, but you'd need a subtitle that says 'Based on Gnome 3', and copyright notices would have to list 'The GNOME Project'. Note that fedora isn't distributed under GPL in one big unit, it's a big cluster of many bits which are each under GPL et al. –  ipeet Dec 17 '11 at 0:58
@thiton: Many thanks, my last confusion is: In Linux i have 1759 packages. My application is included in that 1759. But my application is not using together lets say 1200 packages. But its there as it get shifted by OS. Do i have to list 1759 in my license page or i will be fine if i do 559 which my application is only using? –  YumYumYum Dec 17 '11 at 11:08

IANAL, but this is what I've learned. I would be very interested to know if any of it is incorrect:

GPL: If you statically link it it in your application and you distribute the compiled application then you must release the source under the GPL to anyone who receives the binary.

share|improve this answer
According to my understanding, you just described the LGPL. As thiton said, 'the GPL reaches as far as the address space of the licensed code'. –  ipeet Dec 17 '11 at 0:53

GPL is NOT compatible with closed source. If they used GPL-licensed packeges/modules and closed the source, in the general case they would be in violation of the GPL conditions.

share|improve this answer
A large company did this, where Busybox itself is GPL and they used zoneinfo http://www.twinsun.com/tz/tz-link.htm LGPL and there embedded device is closed source, doing business more then many years. Will you still say they are violating GPL condtions? –  YumYumYum Dec 16 '11 at 15:10
@Google: Okay, so a company did something for quite a few years. Are you saying that makes it legal? Using that reasoning, exceeding the speed limit for driving would be legal around here. –  David Thornley Dec 16 '11 at 15:18
@DavidThornley: Well unfortunately its not me. The company who is doing it is not legal or legal is not clear because in IT Law, there is not 100% answers available, so trying to understand to avoid doing mistake in my projects, where many others seems to be already have done those mistakes (its only because resources are limited, not available for starters to realized while developing, later it becomes like a nightmare, like in my case i am having). –  YumYumYum Dec 16 '11 at 15:21

There are clear cases and then some muddy one for which you'll get more opinion that lawyers you present the case.

Your rules match my understanding, but what will vary is the precise definition of "use". The copyright system on which the license is based isn't about "use" but about "creating a derived work" and some will argue with good arguments that a system made of different programs may be such that the different programs are tied enough that the whole system is a derived work of any one of them while another single program dynamically linked to a library isn't a derived work of the library because the library implement a clearly defined protocol and could be replaced (I've seen libreadline used in such a way with a simple GPLed wrapper to match an application provided interface). Ask your lawyer for advice specific to your case. See you before the judge if the one of the copyright holder isn't of the same opinion.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.