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

[Warner Losh <imp@bsdimp.com>]

From: Luke -Jr <luke@dashjr.org>
Subject: Re: [Qemu-devel] QEMU License and proprietary hardware
Date: Fri, 22 Jun 2007 10:18:01 -0500

> 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.

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.

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).

However, those exceptions tend to be rather specialized and limited.
This isn't just GPL, btw, but any creative work.  It is at the heart
of the SCO case because SCO is claiming ~500 lines of Linux infringe
on its copyright rights (to grossly oversimplify).  Much of IBM's
defence rests on exceptions to copyright law.

> IANAL either, but as much as I have to debate this I might as well be

It is amaizing how many people get this wrong.  It is subtle, and
there's much misinformation circulating.  I've had to do a lot of
research in this area because of my involvement in FreeBSD's core team
and the licensing issues that come up there...

Warner