avformat/allformats: Fix data race when accessing devices lists

Up until now setting the input and output devices lists is guarded
by a mutex. This prevents data races emanating from multiple concurrent
calls to avpriv_register_devices() (triggered by multiple concurrent
calls to avdevice_register_all()). Yet reading the lists pointers was
done without any lock and with nonatomic variables. This means that
there are data races in case of concurrent calls to
av_(de)muxer_iterate() and avdevice_register_all() (but only if the
iteration in av_(de)muxer_iterate exhausts the non-device (de)muxers).

This commit fixes this by putting said pointers into atomic objects.
Due to the unavailability of _Atomic the object is an atomic_uintptr,
leading to ugly casts. Switching to atomics also allowed to remove
the mutex currently used in avpriv_register_devices().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

0 files changed, 0 insertions, 0 deletions