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

[M. Warner Losh]

In message: <address@hidden>
            Luke -Jr <address@hidden> writes:
: 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...

The definition is what is controlling here.  IF it is a derived work
THEN you must do X.  If it is not a derived work, then you may do as
you see fit.  If what you did somehow wasn't a derivative work, then
the there's no legal basis for forcing compliance with a license.
This is exactly what SCO is trying to do right now with its IBM case.

: > 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.

Even if it didn't, you would be able to.  Running a program on a
kernel does not create a derivative work.  I believe there is even
case law on this.  IIRC, there were cases with IBM and third parties
providing software for mainframes that settled this, but I don't have
the time to do an Internet search here.

It is unclear for the Linux kernel if the 'end run' people do with
loadable modules is a legal way to avoid source distribution.  The FSF
doesn't think so.  Linus has said he's cool with it, but absent a
statement from all the copyright holders of code in the Linux kernel,
the issue is at best murky.  It is unclear if the original poster
tried to do a binary-only module with QEMU if he'd be in compliance or
not (since the end user does the actual linking).

: > 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"?

Again, this is another example of how the GPL isn't absolute.  There
is case law in reverse engineering cases for game consoles where it
was held to be fair use to copy the ROMs into memory for the purpose
of reverse engineering them.  There may be other examples where
linking, or linking-like activities are fair use.  The biggest one
being when the original post links in his proprietary module to QEMU.
That's definitely fair use.  Distributing the results may or may not
be legal, depending on how the linking is done and a bunch of other
factors.

Warner