and the caller requested other process' PID by passing non-NULL pidptr
argument, we will wait at most 100ms for the PID to show up in the file and if
it won't, we will store -1 in *pidptr.
From now on, pidfile_open() function never sets errno to EAGAIN on failure.
In collaboration with: des
MFC after: 1 week
success and zero pid from pidfile_read(). Return EAGAIN instead. Sleep
up to three times for 5 ms while waiting for pidfile to be written.
mount(8) does the kill(mountpid, SIGHUP). If mountd pidfile is truncated,
that would result in the SIGHUP delivered to the mount' process group
instead of the mountd.
Found and analyzed by: Peter Holm
Tested by: Peter Holm, kris
Reviewed by: pjd
MFC after: 1 week
to pidfile_write happen, the pidfile will have nul characters prepended
due to the cached file descriptor offset...
Reviewed by: scottl
MFC after: 3 days
