Date: Tue, 12 Mar 2013 21:16:32 +0100 From: Dirk Engling <erdgeist@erdgeist.org> To: freebsd-current@freebsd.org Subject: pidfile_open incorrectly returns EAGAIN when pidfile is locked Message-ID: <513F8D20.2050707@erdgeist.org>
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While debugging my own daemon I noticed that pidfile_open does not
perform the appropriate checks for a running daemon if the caller does
not provide a pidptr to pidfile_open
fd = flopen(pfh->pf_path,
O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
fails when another daemon holds the lock and flopen sets errno to
EAGAIN, the check 4 lines below in
if (errno == EWOULDBLOCK && pidptr != NULL) {
means that the pidfile_read is never executed.
This results in my second daemon receiving an EAGAIN which clearly was
meant to report a race condition between two daemons starting at the
same time and the first one not yet finishing pidfile_write.
The expected behavior would be to set errno to EEXIST, even if no pidptr
was passed.
Regards,
erdgeist
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