Re: [Qemu-devel] Re: Sponsorship for QEMU Developers...

["John R. Hogerhuis" <jhoger@pobox.com>]

On Sat, 2005-03-05 at 21:48 -0500, Leonardo E. Reiter wrote:

> Let me state my intentions again: we want to do everything we can to 
> sponsor QEMU to make it better and keep it free.  We are not interested 
> in stealing its code and selling it.  The closed-source value added 
> functionality that we sell is entirely home-grown, and we have taken all 
> the precautions necessary to avoid contamination.  We would also like to 
> contribute significantly ourselves in the form of code.  For example, a 
> patch that converts the QEMU library and PC emulator into a shared 
> library could be useful for many other projects, not just Win4Lin. 
> While we don't expect Fabrice to admit it officially, we will certainly 
> offer it to the community.  Like that piece, there will be others as well.
> 

Leo,

I don't think anyone is accusing you of attempting to steal QEMU. You
are in fact, graciously making an offer to support development and are
being honest and open about your intent. That's fantastic.

I think the problem that Robert is referring to is that by turning QEMU
into a shared library, and linking that library into your closed source
code, you are (albeit dynamically) linking your closed source code to
GPLed code. In such a situation, you could, say, distribute your work by
itself, and have users download QEMU on their own. Otherwise, since you
are linking to the code (directly or indirectly, it doesn't matter), you
are prevented by the GPL from shipping the combined work unless
recipients can request and get the source code to *both* the closed
source parts and QEMU under a GPL license. At least that's the way I
have come to understand the implications of the GPL.

Otherwise, you would technically be guilty of copyright infringement if
you distribute both together and fail to release your closed source
parts if asked to by one of your customers. What that means practically
is up to the copyright holders. They may or may not care, or may ignore
transgressions when it is in their interest to do so. In such a case, no
immediate problem for you or anyone.

Of course there are limits here... your code, for instance, is in no
direct danger of having to be GPLed or anything like that, which is a
common misconception. The only danger for you is being sued for
copyright infringment.


It just appears to me and probably others that while you are making a
conscientious effort to avoid doing so, you are in fact "contaminating"
your code by linking to GPLed code. This is what the LGPL license is
for, it allows linking to GPLed code. If anyone could just throw a
wrapper around a GPLed binary and magically make its GPLed'ness
disappear, there would be no need for the LGPL. Including header files
would certainly trigger 'linking' provisions of the GPL. *Not* including
header files doesn't really mean anything. Dynamic linking is still
linking.

One way around this is negotiating directly with the copyright holders
for a different license. I hope you are able to work something out which
is in yours and everyone's best interest.

Good luck, hopefully this makes sense... I'm no lawyer, which is
information advice is free... do with it what you will.

-- John.