[copyleft-next] exceptions/additional-permissions & weak copyleft

Theodore Ts'o tytso at mit.edu
Fri Aug 3 17:45:51 UTC 2012


On Fri, Aug 03, 2012 at 10:50:56AM -0400, Bradley M. Kuhn wrote:
> I long ago noticed that most developers have in their head a belief of
> what any LGPL (v2 or v2.1 or v3) means to allow and to prohibit.  Sadly,
> that view in their heads rarely matches the text of the license.  

What are the most common misconceptions you've noted when talking to
developers?

My perspective (but I'm someone who's actually *taken* one or two I/T
and law classes at the MIT Sloan School, so obviously I'm far too
well-informed to be able to give a valid opinion or to be seated on a
jury :-) is that most developers think about things in terms of shared
libraries, since that's how 99% of libraries are consumed these days.
Hence, many developers simply want to allow a non-GPL-compatible
program to be able to use their library.

A lot of the misconceptions I think have come from FSF partisans
wanting to stretch the concept of what is covered by derivitive works
as far as possible.  As I've often been fond of asking, suppose you
wrap a GPL'ed library via RPC's, and then call the GPL'ed library from
another machine across the internet --- does the program which call
said library become a derived work?  That is, does the GPL virus
infect across an RPC call across the internet?

Now what if the RPC server is called via localhost, or a unix domain
socket?  Does the GPL virus infect across a local RPC call?

Now what if you use a shared library?  Is a program which calls the
shared library a derived work of the GPL'ed shared library?

Now what if you are using a language like Java, where the author
calling program may have absolutely no idea whether the library it is
calling is in the same address space, or in a different JVM on the
same machine, or across the network on a different server.  (In fact,
this might be a run-time or real-time dynamic configuration decision
made by the system administrator or by automated load balacing
software.)  Is the calling program a derived work of a GPL'ed library
which *might* be in the same address space?

The reason for bringing up this old and tired issue now is to point
out that if it was well accepted that callers of shared libraries did
not form a derived work, the demand for weak copyright would have
fallen to near-zero.

So if the FSF's goal was to promote strong copyleft, and to discourage
weak copyleft, my claim is their attempt to make what I consider to be
an overreaching claim for what might considered the bounds of a
derived work and what might be considered fair use has probably harmed
their own stated goals.

						- Ted


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