Hello,
I'm getting a bug report against VLC media player whereby ALSA sound output stops working when the screensaver is inhibited. It turns out that VLC is leaking any file descriptor open through ALSA-lib into child processes. The exact same issue was already raised by mplayer... 6 years ago: http://www.mail-archive.com/alsa-devel@lists.sourceforge.net/msg06249.html
In other cases (V4L, OSS, DVB, DVD, sockets, even regular files...), VLC would open the device nodes with O_CLOEXEC flag (if supported by kernel and libc) and fallback to setting FD_CLOEXEC via fcntl(). Then the descriptor is automatically, and in the earlier case, thread-safely, closed whenever VLC - forks and- execs. With ALSA-lib, I cannot figure any way to achieve that...
From the earlier thread, I reckon that ALSA developers consider that this is an upper-layer issue. Maybe so, but then how is the upper-layer supposed to find which file descriptors ALSA-lib has opened - if any? Conversely, if ALSA- lib won't tell while file descriptors it is using, what could possibly be the use case for not closing those on exec?
Best regards,