Can a user redistribute pay-only GPL derivative? and more...

[Joseph Heenan]

Ralph Corderoy wrote:
> Hi Joseph,
> 
> 
>>>4)      Is there any difference for interpreted script programs (ala
>>>PHP) where the source essentially is the program?
>>
>>Yes, slightly. It is possible that the source code supplied by the
>>second party is obfuscated. To distribute that work under the GPL,
>>they would be required to provide a non-obfuscated source on request,
>>possibly for the payment of a small fee.
> 
> 
> Very good point.  Section 3 has the relevant text:
> 
>     "The source code for a work means the preferred form of the work for
>     making modifications to it.  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.
<snip>

> I've always wondered why "plus the scripts used to control compilation
> and installation of the executable" isn't enforced more.  AIUI,
> Stallman's intent with this part of the GPL was to be able to modify the
> software that comes on a device, so just having the source that matched
> the embedded binaries wasn't any use without also the means to install
> your binaries built from the source after you'd modified it.

Yes, that definitely seems to be the intent. Some of the clauses in the 
LGPL it clear that where a program uses a LGPL library the user should 
be able to modify that library and use their modified version within the 
closed-source program. I don't think Stallman had really anticipated the 
embedded software market though.

I'm really not sure what it's not enforced more. I guess in a lot of 
cases it's simply less hassle to figure out what's necessary independently.

> Take Sir Alan Sugar's company, Amstrad.  In the UK they sold the E3, a
> videophone, which ran Linux.  It has a stereo jack socket on the back
> labelled "EXT" which the manual says is for factory use only.  Turns out
> it's a serial port.  In email, the E3's designer at Amstrad said they
> used it during development, and also to download new firmware releases
> to models sitting in the factory.  The non-GPL'd bootloader in the
> device understands a protocol over that serial port to allow the
> firmware to be flashed.  Doesn't the GPL mean that Amstrad should
> release that protocol?  Not the bootloader's source, since it is an
> in-house program developed from scratch, but document the protocol
> required to replace the GPL'd code.

It seems like they'd be required to distribute the firmware loader, 
under the "plus the scripts used to control compilation and installation 
of the executable" clause. It's a shame the word "scripts" is used there 
though, and there's no definition of it within the license. (I can't see 
anything that would require them to release the protocol, only the 
"script" that talks the protocol to install the firmware.)

> However, it's rumoured that the Amstrad-manufactured PVRs may be running
> Linux.
> 
>     http://www.advogato.org/article/911.html

I'd not previously heard of any of the sky digiboxes/pvrs running linux. 
(and to be honest there are a lot of other inaccuracies and 
misunderstandings in that article, not least that he says GPLv2 when he 
seems to mean GPLv3.)

Joseph