[ale] License goop...

[Chris Fowler]

It is okay to symbolically link against GPL software.  You can not
statically link unless your software is open.

-----Original Message-----
From: Ken Kennedy [mailto:kkennedy at kenzoid.com]
To: ale at ale.org
Sent: Saturday, February 02, 2002 6:09 PM
To: Ale (E-mail)
Subject: Re: [ale] License goop...


On Thu, Jan 31, 2002 at 12:26:52AM +0000, Joseph A Knapka wrote:

> <cue ominous organ music>
>
> Let's say there's a commercial, closed-source product,
> WhizBangAppServer, that publishes an API for dynamically-
> loaded extensions. I write an extension that implements
> the WBAS API. Assume I do this in a sealed room with
> no access to the outside world save an air vent and
> a beer tube, and specifically with no access to any
> open-source code that might compromise my proprietary-ness.
> After I finish my extension, I'm released from cleanroom
> captivity.
>
> Now, there's an open-source, GPL'd product, GnuAgeAppServer,
> that has cloned the WBAS and publishes the same API. As
> an experiment, I test my WBAS extension under GAAS, and lo
> and behold, it works! Yay! Except... have I just been
> forcibly open-sourced by the act of running my extension
> under GAAS? Could *anyone else* have likewise "outed" my
> closed-source code by buying it and then running it under
> GAAS?

Don't worry...you can't be "forcibly" GPL'd in this fashion. Your
code...is your code. The GPL respects copyright, in fact it RELIES on
copyright to perform it's "copyleft"-ness. The only way you can be
required to GPL your code is if you USED GPL'd code in your
extension. That's part of the rules; "we give freely, but you can't
take without giving back as well".

However...you DID break the licensing agreement, in the sense of
linking to the GPL'd software. Different issue. If you refuse to
release your plugin under the GPL or a GPL-compatible Free Software
license, you do not have permission (from the copyright holder of the
GPL'd GAAS) to link to the main GAAS.

Similarly, if you don't PAY for WBAS (the closed-source product...I'm
assuming it isn't no-cost software here), you don't have permission to
link to it. Both legal questions, having nothing to do with the fact
that the software is techinically capable of doing it.

Again, this also depends on HOW the plug-ins work. Again, from the GPL
faq:

> > Q: If a program released under the GPL uses plug-ins, what are the
> > requirements for the licenses of a plug-in?
> >
> > A: It depends on how the program invokes its plug-ins. If the program
> > uses fork and exec to invoke plug-ins, then the plug-ins are separate
> > programs, so the license for the main program makes no requirements
> > for them.
> >
> > If the program dynamically links plug-ins, and they make function
> > calls to each other and share data structures, we believe they form a
> > single program, so plug-ins must be treated as extensions to the main
> > program. This means they must be released under the GPL or a
> > GPL-compatible free software license.
> >
> > If the program dynamically links plug-ins, but the communication
> > between them is limited to invoking the `main' function of the plug-in
> > with some options and waiting for it to return, that is a borderline
> > case.

Later!

--

Ken Kennedy	| http://www.kenzoid.com	| kenzoid at io.com


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