[libvirt] [Qemu-devel] JSON license is non-free - how are we affected?

[Anthony Liguori]

On 05/22/2012 10:51 AM, Eric Blake wrote:
> The QMP monitor uses JSON as its underlying base.  However, when you
> read the license of JSON [1], you will note that it has a pretty severe
> limitation ("The Software shall be used for Good, not Evil").  In fact,
> this limitation is severe enough that the FSF has declared that the JSON
> license is non-free (even if the limitation is unenforceable), and
> therefore cannot be combined with GPL code:
>
> [1] http://www.json.org/license.html
> [2] https://www.gnu.org/licenses/license-list.html#JSON
>
> How do we reconcile this?  Obviously, qemu must remain GPL, because it
> has files that are licensed GPLv2, and the overall license is the
> restrictive union of all source licenses.  But that implies that we
> cannot include any source code or libraries provided by json.org, if
> such code is under the incompatible JSON license.
>
> Is the JSON license only applicable to code downloaded from json.org,
> but not to the actual JSON language specification?  If so, does that
> mean that a clean-room implementation of JSON (the language
> specification) can be written with different license than JSON (the
> license), and that such alternate code could then be linked into qemu?
> Is this already the case?  It would be a shame to have to reinvent QMP
> to use a different language specification if the entire JSON language is
> deemed poisoned.

Hi Eric,

When evaluating JSON implementations, I looked at the json.org license and 
immediately sought other options.  I was very aware that that clause would not 
be GPL compatible.  Ultimately, we wrote our own from scratch based on the JSON 
RFC[1].

There is no dubious claims in the RFC and I don't think there could be as it's 
simply a strict subset of the EMCA specification.

At no point have I ever looked at the json.org source but given the fact that 
the license is moronic, I expect the implementation to be equally dumb and 
wouldn't even consider it even if the license was changed at this point.

[1] http://www.ietf.org/rfc/rfc4627

Regards,

Anthony Liguori

>
> Thoughts?  Do we need to seek legal guidance from FSF, Red Hat, or any
> other organization on how to proceed?
>