[sword-devel] Closed source exploitation of open source works (a GPL loophole)

Paul Gear sword-devel@crosswire.org
Thu, 10 May 2001 08:49:10 +1000

Chris Little wrote:

> ...
> It might be a bit slower than most front ends, but you could use
> ActiveDiatheke to build a front end with most of the same capabilities as
> BibleCS, GnomeSword, BibleTime or iraeneus.  The big difference would be
> that the author of such a program would have no need to release his work
> under GPL because it is not modifying or even statically linking Sword
> derived code.
> So . . .
> What's our answer to this loophole in the GPL?  Do we find a more
> restrictive license than GPL under which to release ActiveDiatheke (and
> probably Sword in general since anyone could make a similar component and
> license under GPL, allowing close source use)?  We've considered switching
> to LGPL, so should we just ignore this issue since it meshes just fine with
> the intent behind LGPL.  Should we allow ActiveDiatheke (and similar) to go
> under GPL and serve as a the only means for closed source use rather than
> putting Sword under LGPL?  Should I just pretend I didn't write it and
> delete it from my hard drive so that we don't have to deal with the issue at
> all? :)

My understanding of the letter of the GPL here is that it is ambiguous - it
does not specify issues relating to linking.  My understanding of the spirit of
the GPL (and i have discussed this personally with RMS) is that linking is not
a relevant issue.  It doesn't make any difference whether a program is
dynamically or statically linked.  The issue is whether or not the hypothetical
closed source code and the GPLed code together constitute a program.

Here is the relevant part of the GPL (from section 2):

> These requirements apply to the modified work as a whole. If identifiable
> sections of that work are not derived from the Program, and can be reasonably
> considered independent and separate works in themselves, then this License,
> and its terms, do not apply to those sections when you distribute them as
> separate works. But when you distribute the same sections as part of a whole
> which is a work based on the Program, the distribution of the whole must be
> on the terms of this License, whose permissions for other licensees extend to
> the entire whole, and thus to each and every part regardless of who wrote it.

Applying this to our situation, i would say that ActiveDiatheke is 'derived
from the Program [Sword]' (because its sole purpose is to provide an interface
to Sword facilities) and thus would fall under the GPL (although we should
distribute it as part of Sword to make sure this is clear), whereas any work
using ActiveDiatheke would not constitute a work 'derived from the Program'
because it would simply be using services provided by it (especially if it were
distributed as a separate work).

A similar example (IMO) would be writing an SMTP server based on a GPL-ed
networking library.  The server itself would be GPL-ed because it was a work
derived from the library, whereas any email client connecting to the SMTP
server would simply be using the services it provides, without being subject to
the GPL.

Therefore i conclude that this is not a loophole, but the GPL working as
designed.  IANAL, so i would be interested in hearing whether anyone disagrees
with me.  Having followed free software licensing debates for some time and
spoken with RMS about this, i think i've got the ideas pretty straight.  What
do you think, Jerry, Troy, others?

"He must become greater; i must become less." - John 3:30