pthread_mutex_lock() will only return an error if it was set to
PTHREAD_MUTEX_ERRORCHECK and we are recursively calling it (and
would otherwise have deadlocked). If that's the case then log a
message for future debugging and exit. Trying to "recover" is
nonsense at that point.
process_lock() was held over too long a time in lxcapi_start()
in the daemonize case. (note the non-daemonized case still needs a
check to enforce that it must NOT be called while threaded). Add
process_lock() at least across all open/close/socket() calls.
Anything done after a fork() doesn't need the locks as it is no
longer threaded - so some open/close/dups()s are not locked for
that reason. However, some common functions are called from both
threaded and non-threaded contexts. So after doing a fork(), do
a possibly-extraneous process_unlock() to make sure that, if we
were forked while pthread mutex was held, we aren't deadlocked by
nobody.
Tested that lp:~serge-hallyn/+junk/lxc-test still works with this
patch.