Ending a RTSP session while running on OpenBSD using sndio backend causes the
following crash:
#0 thrkill ()
#1 0x000005208224403e in _libc_abort
#2 0x00000520821b77be in _rthread_mutex_trylock
#3 _rthread_mutex_timedlock
#4 0x0000051e0d54e2c0 in stop ()
#5 0x0000051e0d544e85 in player_thread_cleanup_handler
#6 0x0000052082243126 in _libc_pthread_exit
#7 0x000005209a158700 in sigthr_handler
#8 <signal handler called>
#9 _thread_sys_poll ()
#10 0x000005208223533e in _libc_poll_cancel
#11 0x00000520df54c9a0 in sio_psleep
#12 0x00000520df54cc1f in sio_write
#13 0x0000051e0d54e27a in play
#14 0x0000051e0d547fc0 in player_thread_func
#15 0x000005209a158cc1 in _rthread_start
#16 0x000005208223565a in __tfork_thread
The player thread is blocking inside sio_write() -> poll(2) while the thread is
being terminated. The stop routine tied to the same backend is invoked through
player_thread_cleanup_handler() which tries to acquire the mutex which it
already acquired before invoking sio_write(). Avoiding blocking writes would
require switching to async I/O which is quite an undertaking.
The fact that there's only one `struct sio_hdl *' instance in the compilation
unit sort of implies there can only be one player thread at a time. Therefore
fix the crash by only trying to acquire the mutex and continue as usual if it's
already acquired.
The OS whitelist conditional is malformed due to missing test(1) commands
causing the following error to be emitted during configure while using something
other than Linux:
../configure[3340]: xopenbsd: not found
Instead, favor a switch statement which makes the line a bit shorter as well.
Also, the AC_MSG_ERROR argument must be wrapped in brackets due to presence of a
comma. Otherwise, the tail will be interpreted as an additional argument.
Anton Lindqvist