diff options
| -rwxr-xr-x | archivemail.py | 45 |
1 files changed, 33 insertions, 12 deletions
diff --git a/archivemail.py b/archivemail.py index 39ba776..fb7bd8a 100755 --- a/archivemail.py +++ b/archivemail.py @@ -67,6 +67,7 @@ import string import tempfile import time import urlparse +import errno # From_ mangling regex. from_re = re.compile(r'^From ', re.MULTILINE) @@ -410,21 +411,41 @@ class Mbox(mailbox.UnixMailbox): def procmail_lock(self): """Create a procmail lockfile on the 'mbox' mailbox""" + import socket + hostname = socket.gethostname() + pid = os.getpid() + box_dir, prelock_prefix = os.path.split(self.mbox_file_name) + prelock_suffix = ".%s.%s%s" % (hostname, pid, options.lockfile_extension) + plfd, prelock_name = tempfile.mkstemp(prelock_suffix, prelock_prefix, + dir=box_dir) lock_name = self.mbox_file_name + options.lockfile_extension attempt = 0 - while os.path.isfile(lock_name): - vprint("lockfile '%s' exists - sleeping..." % lock_name) - time.sleep(options.lockfile_sleep) - attempt = attempt + 1 - if (attempt >= options.lockfile_attempts): - unexpected_error("Giving up waiting for procmail lock '%s'" - % lock_name) - vprint("writing lockfile '%s'" % lock_name) - old_umask = os.umask(022) # is this dodgy? - lock = open(lock_name, "w") + try: + while True: + attempt = attempt + 1 + try: + os.link(prelock_name, lock_name) + # We've got the lock. + break + except OSError, e: + if os.fstat(plfd)[stat.ST_NLINK] == 2: + # The Linux man page for open(2) claims that in this + # case we have actually succeeded to create the link, + # and this assumption seems to be folklore. + # So we've got the lock. + break + if e.errno != errno.EEXIST: raise + # Lockfile already existed, someone else has the lock. + if (attempt >= options.lockfile_attempts): + unexpected_error("Giving up waiting for " + "procmail lock '%s'" % lock_name) + vprint("lockfile '%s' exists - sleeping..." % lock_name) + time.sleep(options.lockfile_sleep) + finally: + os.close(plfd) + os.unlink(prelock_name) _stale.procmail_lock = lock_name - lock.close() - old_umask = os.umask(old_umask) + vprint("acquired lockfile '%s'" % lock_name) def procmail_unlock(self): """Delete the procmail lockfile on the 'mbox' mailbox""" |