> Some syscalls can fail with EINTR, when a signal hits while within the
> kernel. This is especially true for flock(LOCK_EX) because in the
> already-locked case the second call will go to sleep for a while waiting
> for the lock to clear. But it is also possible, I think, for the
> pread/read/write calls. The usual handling for the case (-1 return &&
> errno
> == EINTR) is to just repeat the call in a while loop. I think that at
> least
> doing so for the LOCK_EX calls, would be prudent.
Re-Read the manpage (*) a bit... read/pread/write should be safe here, going
to disk, and not a pipe or socket. But flock() will return EINTR when
signalled and the signal handler did not use SA_RESTART. Most PHP execution
will _probably_ okay anyway as $restart_syscalls is default true for
pcntl_signal(), but handling would be safer anyway.
Patrick
(*) search for SA_RESTART in http://man7.org/linux/man-pages/man7/signal.7.html