libcec: Please stop linking to GPL-incompatible libraries

[Balint Reczey]

The GPL lincensed libcec source package is compiled linking to libraries in /opt/vc/lib:
from debian/rules:
...
    cmake -DRPI_INCLUDE_DIR=/opt/vc/include -DRPI_LIB_DIR=/opt/vc/lib
...

As a result libcec4 is linked to several libraries in /opt/vc/lib:

$ ldd /usr/lib/arm-linux-gnueabihf/libcec.so.4.0.4 | grep opt
 libvcos.so => /opt/vc/lib/libvcos.so (0x76c4c000)
 libvchiq_arm.so => /opt/vc/lib/libvchiq_arm.so (0x76c36000)
 libbcm_host.so => /opt/vc/lib/libbcm_host.so (0x76c0f000)

The license of those libraries is however _not_ GPL compatible:

$ dpkg -S /opt/vc/lib/libvcos.so
libraspberrypi0: /opt/vc/lib/libvcos.so

$ cat /usr/share/doc/libraspberrypi0/copyright:
...
Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Source: http://github.com/raspberrypi/firmware

Files:
 opt/vc/bin/*
 opt/vc/lib/*
 opt/vc/sbin/*
 boot/*.bin boot/*.elf
Copyright: 2006-2012 Broadcom Eurpe Ltd.
License: Broadcom
 All rights reserved.
 .
 Redistribution. Redistribution and use in binary form, without
 modification, are permitted provided that the following conditions are
 met:
 .
 * This software may only be used for the purposes of developing for,·
   running or using a Raspberry Pi device.
...

Since the libraries linked to are not GPL compatible the resulting libcec4 shared libraries can't be distributed under the GPL license - or under any other license given that the libcec source code is under GPL.

I found this issue while trying to solve the https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=921878 bug reported to Debian about adding support for Raspberry PI's CEC interface. Unfortunately until the legal issue is resolved this is not possible - nor it seems to be legal for Raspbian to distribute the current libcec packages.

Please consider releasing the linked libraries under a GPL-compatible license to resolve the situation.

[peter green (plugwash)]

Afaict these libraries are not being distributed by raspbian per-se but by the raspberry pi foundation as part of the packages they build on top of raspbian. So this needs to be discussed with them, not with us.

Having said that I belive that the debian/copyright file you are linking may be out of date. The source code for those libraries was released some time ago under a 3-clause BSD license. https://github.com/raspberrypi/userland

[Dave Jones (waveform)]

Yup, the userland repo does indeed contain the source for the libraries concerned (libbcm_host.so, libvcos.so, and libvchiq_arm.so). It also, as plugwash notes, has a GPL-compatible 3-clause BSD license.

The bit I haven't been able to verify yet is whether the libraries within the libraspberrypi0 package are the versions built from the https://github.com/raspberrypi/userland repo (they likely are as that repo still sees a fair bit of activity and that package is updated pretty regularly too - still, it'd be nice to verify this for certain), in which case it would simply be a matter of d/copyright being out of date.

Anyway, I'll ask Serge if he can fix up the license for the next release.

[Balint Reczey (rbalint)]

With the userland now present in Ubuntu it may be possible to build libcec with RPi support:
https://launchpad.net/ubuntu/+source/raspberrypi-userland

I don't use any RPi though, thus I'd appreciate feedback if the fixed package works.