Re: Dual-Licensing Linux Kernel with GPL V2 and GPL V3

From: Ingo Molnar
Date: Thu Jun 14 2007 - 21:26:52 EST

* Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> > the GPLv2 license says no such thing, and you seem to be mighty
> > confused about how software licenses work.
> There is no such thing as a software licence. It is a copyright
> licence.

a "software license" is a common shortcut for "copyright license for
copies of software works". It's a commonly used phrase. In fact it is
used by the FSF itself too:

"To decide whether a specific software license qualifies as a free
software license, we judge it based on these criteria to determine
whether it fits their spirit as well as the precise words."

> > the GPL applies to software. It is a software license.
> You can GPL a new graphical logo you painted on your toilet seat, you
> can GPL hardware designs. It might not be a good licence for either
> but it is a valid licence.

yeah - the GPL can be applied to most types of works recognized by
copyright law.

> > the Tivo box is a piece of hardware.
> A Tivo box is a collection of literary works protected by copyright,
> designs protected by design patents and copyright, names and logos
> protected by trademarks, functionalities protected by patents and many
> more things. These are the things that restrict what I may do with it
> and how I may treat it. The collection of bits of metal and sand
> aren't really of relevance in terms of licencing.

If you are into technicalities then you fail to achieve that "rigorous
base" by a wide margin. The Tivo box is not "a collection of literary
works", it is a piece of matter, that also happens to contain fixated
copies of literary (and other) works. The Tivo box is just one copy of
those works - it is not "a collection of literary works". (Only if there
was just a single Tivo box on the planet then could that box itself be
meaningfully called a collection of works - a single and unique "master
copy" of a work can be called the work itself.)

and that distinction, although fine, is very important. Look at GPLv2
section 0:

" 0. This License applies to any program or other work which contains a
notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. "

the work is not the copy! The work is a more 'abstract' entity. The word
"copyright" comes straight from that: the right to create specific
copies of the work. And that's another reason why it's nonsensical to
suggest that somehow the GPLv2 gives us the right to influence the
hardware environment that the copy of the kernel got fixated into. We
dont. ( unless that hardware environment too is a copy of a GPL-ed work
or it is a copy of a work that is a modification of or derives from a
GPL-ed work - but in the Tivo case it isnt. It's a collection of copies
of works and derivation does not "jump" from the harddisk to the
hardware. )

More down the technicalities road: the Tivo box also contains many items
that are not copies of works protected by copyright: common types of
screws that are not original forms of expression that are creative
enough enough to gain copyright protection. Or numbers painted on
various places. Or computer-originated random output. Copies of works
that have entered the public domain and thus are not under the scope of
copyright protection.

Neither is the Tivo box "collection of functionalities protected by
patents", if then it is an embodiment of a method and apparatus, which
invention is under patent protection (there are other types of patents
as well), or which invention might not be under patent protection but
have a patent application pending. (which might or might not issue at
the end of the patent application process.)

> > a disk is put into it with software copied to it already: a bootloader,
> > a Linux kernel plus a handful of applications. The free software bits
> > are available for download.
> Except the keys - which may nor may not be required depending upon how a
> court (not a mailing list) interprets the phrases
> "The source code for a work means the preferred form of the work for
> making modifications to it"

i think it is clear what is intended with this section: that for example
using automatic tools to strip out comments and obfuscating the source
code does not fly, because what matters is the _form of the software_
the developer usually makes his modifications under. So this in essence
defines the scope of the actual source code that must be made available
so that it works on a general purpose computer, not the specific
hardware environment under which the developer operates.

so i believe it is a ... fairly creative bending of the wording of this
section to attempt to extend it to the hardware environment. You dont
get my ssh keys either [*] that i use on my test-boxes, and those test
boxes are very much part of the preferred way for me to produce kernel
patches. But you get my kernel patches for sure! [ that is, if they dont
crash the testboxes :-) ] Am i violating the GPLv2?

> and
> "For an executable work, complete source code means all the source
> code for all modules it contains, plus any associated interface
> definition files, plus the scripts used to control compilation and
> installation of the executable."

i think it is pretty clear what this section intends: not allowing
people to become cute by stripping out of makefiles from the source
tarball. If someone else tries to run that software on a general purpose
computer (which has enough physical resources for that purpose) it
should be possible.

But to read this to require a toaster that a piece of free software came
installed on to be modifiable by the licensee who choses to excercise
his rights under the GPL, in the same way as the original developer was
able to modify that toaster is ... quite creative too i think, and leads
to many absurd results.

> If you ask the legal profession about this seriously the answer you
> get is bluntly "There is no caselaw I am aware of", which means that
> nobody knows. Obviously Tivo and their legal counsel have formed an
> opinion and have based their actions upon that opinion.

i guess i'll take Linus' word that the FSF's own lawyers agreed that the
distribution of the Tivo box does not break the GPLv2. (although the
cynic in me might say that this could be a self-serving position on
their behalf done for tactical reasons, to increase the perceived
'justification' for the GPLv3.)


[*] actually, you can get them if you want to, because i very much trust
you :-)
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