Re: [Qemu-devel] QEMU License and proprietary hardware

[Luke -Jr]

On Friday 22 June 2007 11:07, you wrote:
> > On Thursday 21 June 2007 17:33, M. Warner Losh wrote:
> > > The GPL only has as much force of law as copyright law gives it, and in
> > > order to be applicable, the work in question must somehow rely on the
> > > GPL'd work.  The "somehow" here is an interesting legal question that
> > > hasn't been well settled.
> >
> > And copyright law by default grants you no rights to modify or copy Qemu
> > at all. The ONLY way you can get permission to copy or modify Qemu is to
> > agree to the GPL in its entirety-- which does not restrict itself to
> > merely derivative works, but covers all linking. (note: obvious the
> > copyright holder(s) can make exceptions to this rule)
>
> Actually, the GPL does only apply to derived works, and it plainly
> says so:
>       The "Program", below, refers to any such program or work, and
>       a "work based on the Program" means either the Program or any
>       derivative work under copyright law
> Linking typically is what makes a derived work, but not necessary.  It
> is just the shade of grey that most people use as a rule of thumb.

That's merely the definition of "Program" as used in the license. Read all the 
requirements, not just definitions...

> If you do not have a derived work, then you can use and distribute
> your work as you see fit, without the GPL restrictions.  While the GPL
> is viral, it is only viral to the extent that the new work is
> derivative of the GPL'd work.  This is why, for example, running my
> proprietary program on a Linux box doesn't mean my proprietary program
> is covered under the GPL.  Although it uses the kernel, and in a very
> real sense the kernel links into the program due to address space
> mapping for system calls and the like, this isn't enough to make my
> program a derivative work.  So it isn't 'black' vs 'white' but more of
> a 'this shade of grey is more white than black' or vice versa.

The kernel contains exceptions for userland code. If it didn't, you would be 
unable to distribute your program alongside Linux.

> I can make "fair use" use of GPL'd software with no restrictions
> what-so-ever so long as that use falls within 'fair use' as defined by
> copyright law.  I can also use GPL'd code that doesn't quaify for
> copyright protection (as is the case if it lacks a creative element,
> is the only possible way to do something, etc).

How does linking fit under "fair use"?