Re: Binaries under GPL(2)

[Walter Landry <wlandry@ucsd.edu>]

Alexander Cherepanov <cherepan@mccme.ru> wrote:
> 8-Dec-03 20:43 Walter Landry wrote:
> > If I give you GPL'd source, then there is only two ways in which you
> > can make modifications, Section 2 and Section 3.  Section 3 allows a
> > particular kind of modification (compilation), and Section 2 allows
> > any kind of modification.
> 
> IMHO there is no such a clear division: Section 2 is about any form
> (or only source form) while Section 3 is about executable form.
> Section 3 is about distribution of executable form and it doesn't
> talk about modification at all. All permissions to modify are in
> Section 2.

Creating an executable is also a way of modifying code.  The code is
translated into machine code, similar to running a document through
babelfish.

> Thus, when distributing binaries compiled from sources, the
> compilation is under Section 2 and the distribution is under Section
> 3. That's part of the original confusion--requirement of source form
> in Section 2 applies only to distribution, not to modification.

Compilation is not covered by the license, only distribution.
Distribution of modified binaries is covered by Sections 2 and 3.
Section 3 lets distribute binaries as long as you distribute source.
Section 2 tells you what you have to do if you modified the source.

> > Distributing binaries under Section 2 probably means
> > editting the binaries with a hex editor.  You also need to have the
> > rights to distribute everything in the binary under the GPL.  With
> > non-free compilers, that may be a problem.  With gcc, that probably
> > means more hex editing to include the FSF, HP, SGI, etc. copyrights.
> 
> The only difference in distribution under Section 2 and under Section
> 3 is the requirement for sources.

True.  That would seem to imply that you have to preserve copyright
notices etc. in all of the modified files.  Otherwise it makes no
sense to refer to the terms of Section 1.  But the usual way of
creating an executable is by running code through a compiler, which
removes most of those notices.  So you could argue that Section 3
gives you permission to do just that.

> > However, it does now seem like a hole in the copyleft.  While possible
> > in principle, I won't stay awake at nights worrying about it.  As
> > Henning said, it is really just an oversight.  The intent is clear,
> > which may sway a court more than the explicit wording.
> 
> The hole in the explicit wording seems to be so clear that I start
> doubting it is just an oversight. Maybe it's normal for sections of a
> license to trump each other?

The hole is there, but exploiting it is hard.  People don't normally
modify machine code.

Regards,
Walter Landry
wlandry@ucsd.edu