Review of GPL code requirements text

[Florian Weimer]

> On Wed, Feb 14, 2007 at 09:56:07PM +0100, Florian Weimer wrote:
>> > If GPL code is modified in order to make improvements, all GPL sources
>> > used must be published so that others can rebuild the GPL code.
>> 
>> The obligation to publish sources is independent of the question
>> whether they have been modified.
>
> But: You are only obligated to publish sources if you also
> publish binaries.

Yes, but publication is just one form of distribution.

> If you make an (embedded?) device, with gpl'd software, and you
> rent that device to a third party, you are not publishing
> software, and hence you don't have to publish source code or
> anything.

Yeah, I know that quite a few people share that belief.  But it hasn't
got any basis in German copyright law (and I would believe that the
way software copyright law has been harmonized across Europe, it's
similar in other EU countries).  Leasing software is an exploitation
right on its own.  Typically, nothing but the GPL gives you permission
to lease the code, so the GPL terms apply.  And those terms call for
access to source code even in this case.

(ASPs are different; it's not clear if you need permission from the
copyright holder before you can offer networked access to the
application.)

> If you modify GPL'd source code for a big company, and give the
> binaries *AND* source code to that big company, neither you or the
> big company are obligated to publish source to a third party.

Sure.

> This part I am not completely sure about:
> If you modify GPL'd source code for a big company, and give the
> binaries *WITHOUT* source code to that big company, you might be
> obligated to publish source code to any third party who asks for
> 3 years or so.

If you don't accompany the binaries with source code, you must provide
a written offer to the receiver.  Anyone can use it to ask for
sources, but before you can do this, you need to have obtained that
written offer.

> Anyway: if you (re)write GPL'd software for third parties, it is
> best to always give the source with the software.

I agree, putting it on the same distribution medium is a safe bet (it
may be a bit tricky for embedded devices, though).