[Buildroot] Is GPLv2 the right license for Buildroot?

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Yann E. MORIN,

On Mon, 16 Sep 2013 20:15:12 +0200, Yann E. MORIN wrote:

> > Whether Buildroot is part of such scripts or not remains a slightly
> > open question. That the kernel makefiles and scripts, the Busybox
> > makefiles and scripts should remain part of the kernel and Busybox
> > sources is clear. That the tool that is used to orchestrate the overall
> > building process is part of those "script to control compilation and
> > installation" is not so clear-cut from my point of view.
> > 
> > At least so far, I don't think I've seen many companies using
> > Buildroot, on products that include GPL components, providing the
> > source code for Buildroot.
> 
> I never said you *had* to provide the Buildroot tree. I said that
> providing it was *easier* than trying to separately provide build
> instructions for each GPL program on the device.

Right. But are there any companies doing any of above? I don't think
I've ever seen a document, or script, or anything like that that
details the build process of the overall system.

I remain unsure that what Buildroot is doing is part of the scripts
governing the compilation of the GPL components.

> > Right, but it is not necessarily easy to separate within Buildroot the
> > thing that you are ready to distribute (package recipes of open-source
> > programs) from the package recipes of proprietary programs, your root
> > filesystem overlay and so on.
> 
> But your BR2_EXTERNAL will make this really trivial:
>   - do all FLOSS stuff in Buildroot tree
>   - do all proprietary stuff in BR2_EXTERNAL
>   - provide the Buidlroot tree to be compliant
>   - keep BR2_EXTERNAL private
> 
> Et voil?! :-)

What a good selling argument for BR2_EXTERNAL :-)

But it isn't quite sufficient: by your definition, the
Buildroot .config should also be shipped, and it also contains config
options for the company-specific proprietary packages. So the .config
should be "filtered" before being released. Not simple.

> > What I'm questioning is really the case where a company makes an
> > embedded product, and has used Buildroot to generate a rootfs that
> > includes GPL programs, is this company required to distribute Buildroot.
> 
> Short answer: no.
> Long answer: no, but it is an easy path.

Aren't companies going to be afraid of revealing too much of their
secret sauce if they have to disclose their Buildroot tree?

My point is also that nobody has ever cared about enforcing the
Buildroot license, and I sincerely doubt anyone will be willing to do
in the foreseeable future. Since no-one cares about that, is it really
necessary to annoy companies with the fairly fuzzy requirements of the
GPL when applied to a build system?

> We just have to settle on what we want to put in there: BR2_EXTERNAL:
> derived work or not? ;-)

If it's considered as a derived work, then your above idea of using
BR2_EXTERNAL to split things between secret stuff and released stuff no
longer works.

> But not before next week, I have to finish my presentations for KR`13
> first! ;-)

Argh, I should do that too!

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com