If we request a /dev/dsp virtual_oss(8) device, we have to replace the
sound(4) one by first disabling hw.snd.basename_clone. This sysctl tells
sound(4) to not create the /dev/dsp alias for the default device. There
are currently two issues with the way this is handled by virtual_oss(8),
however:
1. It uses system(3) instead of sysctlbyname(3).
2. It does not restore hw.snd.basename_clone to its original value, so
if prior to virtual_oss(8) running, hw.snd.basename_clone was enabled
(which is the case by default), and it is closed at some point,
hw.snd.basename_clone stays disabled, which is annoying, because
users have to manually restore it, otherwise applications that open
the default device (i.e., most) will not work.
Fix both issues.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D53621
Christos Margiolis
e5c0d7020f