tree f05df203ee000dde0ce2297cea01a6ef663513d4
parent 1e5f2391704c252fcd01f798a18aa8558376cb1a
author Maxim Dounin <mdounin@mdounin.ru> 1322056538 +0000
committer Maxim Dounin <mdounin@mdounin.ru> 1322056538 +0000

Added shmtx interface to forcibly unlock mutexes.

It is currently used from master process on abnormal worker termination to
unlock accept mutex (unlocking of accept mutex was broken in 1.0.2).  It is
expected to be used in the future to unlock other mutexes as well.

Shared mutex code was rewritten to make this possible in a safe way, i.e.
with a check if lock was actually held by the exited process.  We again use
pid to lock mutex, and use separate atomic variable for a count of processes
waiting in sem_wait().