223
238
except (errors.TransportError, PathError), e:
224
239
self._trace("... failed to create pending dir, %s", e)
225
240
raise LockFailed(self, e)
227
self.transport.rename(tmpname, self._held_dir)
228
except (errors.TransportError, PathError, DirectoryNotEmpty,
229
FileExists, ResourceBusy), e:
230
self._trace("... contention, %s", e)
231
self._remove_pending_dir(tmpname)
232
raise LockContention(self)
234
self._trace("... lock failed, %s", e)
235
self._remove_pending_dir(tmpname)
243
self.transport.rename(tmpname, self._held_dir)
245
except (errors.TransportError, PathError, DirectoryNotEmpty,
246
FileExists, ResourceBusy), e:
247
self._trace("... contention, %s", e)
248
other_holder = self.peek()
249
self._trace("other holder is %r" % other_holder)
251
self._handle_lock_contention(other_holder)
253
self._remove_pending_dir(tmpname)
256
self._trace("... lock failed, %s", e)
257
self._remove_pending_dir(tmpname)
237
259
# We must check we really got the lock, because Launchpad's sftp
238
260
# server at one time had a bug were the rename would successfully
239
261
# move the new directory into the existing directory, which was
240
262
# incorrect. It's possible some other servers or filesystems will
241
263
# have a similar bug allowing someone to think they got the lock
242
264
# when it's already held.
266
# See <https://bugs.launchpad.net/bzr/+bug/498378> for one case.
268
# Strictly the check is unnecessary and a waste of time for most
269
# people, but probably worth trapping if something is wrong.
243
270
info = self.peek()
244
271
self._trace("after locking, info=%r", info)
245
if info['nonce'] != self.nonce:
273
raise LockFailed(self, "lock was renamed into place, but "
275
if info.get('nonce') != self.nonce:
246
276
self._trace("rename succeeded, "
247
277
"but lock is still held by someone else")
248
278
raise LockContention(self)
251
281
(time.time() - start_time) * 1000)
252
282
return self.nonce
284
def _handle_lock_contention(self, other_holder):
285
"""A lock we want to take is held by someone else.
287
This function can: tell the user about it; possibly detect that it's
288
safe or appropriate to steal the lock, or just raise an exception.
290
If this function returns (without raising an exception) the lock will
293
:param other_holder: A LockHeldInfo for the current holder; note that
294
it might be None if the lock can be seen to be held but the info
297
if (other_holder is not None):
298
if other_holder.is_lock_holder_known_dead():
299
if self.get_config().get('locks.steal_dead'):
300
ui.ui_factory.show_user_warning(
302
lock_url=urlutils.join(self.transport.base, self.path),
303
other_holder_info=unicode(other_holder))
304
self.force_break(other_holder)
305
self._trace("stole lock from dead holder")
307
raise LockContention(self)
254
309
def _remove_pending_dir(self, tmpname):
255
310
"""Remove the pending directory
332
388
def break_lock(self):
333
389
"""Break a lock not held by this instance of LockDir.
335
This is a UI centric function: it uses the bzrlib.ui.ui_factory to
391
This is a UI centric function: it uses the ui.ui_factory to
336
392
prompt for input if a lock is detected and there is any doubt about
337
it possibly being still active.
393
it possibly being still active. force_break is the non-interactive
396
:returns: LockResult for the broken lock.
339
398
self._check_not_locked()
340
holder_info = self.peek()
400
holder_info = self.peek()
401
except LockCorrupt, e:
402
# The lock info is corrupt.
403
if ui.ui_factory.get_boolean(u"Break (corrupt %r)" % (self,)):
404
self.force_break_corrupt(e.file_data)
341
406
if holder_info is not None:
342
lock_info = '\n'.join(self._format_lock_info(holder_info))
343
if bzrlib.ui.ui_factory.get_boolean("Break %s" % lock_info):
344
self.force_break(holder_info)
407
if ui.ui_factory.confirm_action(
408
u"Break %(lock_info)s",
409
'bzrlib.lockdir.break',
410
dict(lock_info=unicode(holder_info))):
411
result = self.force_break(holder_info)
412
ui.ui_factory.show_message(
413
"Broke lock %s" % result.lock_url)
346
415
def force_break(self, dead_holder_info):
347
416
"""Release a lock held by another process.
350
419
it still thinks it has the lock there will be two concurrent writers.
351
420
In general the user's approval should be sought for lock breaks.
353
dead_holder_info must be the result of a previous LockDir.peek() call;
354
this is used to check that it's still held by the same process that
355
the user decided was dead. If this is not the current holder,
356
LockBreakMismatch is raised.
358
422
After the lock is broken it will not be held by any process.
359
423
It is possible that another process may sneak in and take the
360
424
lock before the breaking process acquires it.
426
:param dead_holder_info:
427
Must be the result of a previous LockDir.peek() call; this is used
428
to check that it's still held by the same process that the user
429
decided was dead. If this is not the current holder,
430
LockBreakMismatch is raised.
432
:returns: LockResult for the broken lock.
362
if not isinstance(dead_holder_info, dict):
434
if not isinstance(dead_holder_info, LockHeldInfo):
363
435
raise ValueError("dead_holder_info: %r" % dead_holder_info)
364
436
self._check_not_locked()
365
437
current_info = self.peek()
383
455
current_info.get('nonce'))
384
456
for hook in self.hooks['lock_broken']:
460
def force_break_corrupt(self, corrupt_info_lines):
461
"""Release a lock that has been corrupted.
463
This is very similar to force_break, it except it doesn't assume that
464
self.peek() can work.
466
:param corrupt_info_lines: the lines of the corrupted info file, used
467
to check that the lock hasn't changed between reading the (corrupt)
468
info file and calling force_break_corrupt.
470
# XXX: this copes with unparseable info files, but what about missing
471
# info files? Or missing lock dirs?
472
self._check_not_locked()
473
tmpname = '%s/broken.%s.tmp' % (self.path, rand_chars(20))
474
self.transport.rename(self._held_dir, tmpname)
475
# check that we actually broke the right lock, not someone else;
476
# there's a small race window between checking it and doing the
478
broken_info_path = tmpname + self.__INFO_NAME
479
broken_content = self.transport.get_bytes(broken_info_path)
480
broken_lines = osutils.split_lines(broken_content)
481
if broken_lines != corrupt_info_lines:
482
raise LockBreakMismatch(self, broken_lines, corrupt_info_lines)
483
self.transport.delete(broken_info_path)
484
self.transport.rmdir(tmpname)
485
result = lock.LockResult(self.transport.abspath(self.path))
486
for hook in self.hooks['lock_broken']:
387
489
def _check_not_locked(self):
388
490
"""If the lock is held by this instance, raise an error."""
513
612
new_info = self.peek()
514
613
if new_info is not None and new_info != last_info:
515
614
if last_info is None:
516
start = 'Unable to obtain'
615
start = gettext('Unable to obtain')
518
start = 'Lock owner changed for'
617
start = gettext('Lock owner changed for')
519
618
last_info = new_info
520
formatted_info = self._format_lock_info(new_info)
619
msg = gettext('{0} lock {1} {2}.').format(start, lock_url,
521
621
if deadline_str is None:
522
622
deadline_str = time.strftime('%H:%M:%S',
523
time.localtime(deadline))
524
lock_url = self.transport.abspath(self.path)
525
self._report_function('%s %s\n'
527
'%s\n' # locked ... ago
528
'Will continue to try until %s, unless '
530
'If you\'re sure that it\'s not being '
531
'modified, use bzr break-lock %s',
623
time.localtime(deadline))
625
msg += '\n' + gettext(
626
'Will continue to try until %s, unless '
627
'you press Ctrl-C.') % deadline_str
628
msg += '\n' + gettext('See "bzr help break-lock" for more.')
629
self._report_function(msg)
539
630
if (max_attempts is not None) and (attempt_count >= max_attempts):
540
631
self._trace("exceeded %d attempts")
541
632
raise LockContention(self)
620
704
if 'lock' not in debug.debug_flags:
622
706
mutter(str(self) + ": " + (format % args))
708
def get_config(self):
709
"""Get the configuration that governs this lockdir."""
710
# XXX: This really should also use the locationconfig at least, but
711
# that seems a bit hard to hook up at the moment. -- mbp 20110329
712
# FIXME: The above is still true ;) -- vila 20110811
713
return config.GlobalStack()
716
class LockHeldInfo(object):
717
"""The information recorded about a held lock.
719
This information is recorded into the lock when it's taken, and it can be
720
read back by any process with access to the lockdir. It can be used, for
721
example, to tell the user who holds the lock, or to try to detect whether
722
the lock holder is still alive.
724
Prior to bzr 2.4 a simple dict was used instead of an object.
727
def __init__(self, info_dict):
728
self.info_dict = info_dict
731
"""Return a debugging representation of this object."""
732
return "%s(%r)" % (self.__class__.__name__, self.info_dict)
734
def __unicode__(self):
735
"""Return a user-oriented description of this object."""
736
d = self.to_readable_dict()
738
u'held by %(user)s on %(hostname)s (process #%(pid)s), '
739
u'acquired %(time_ago)s') % d)
741
def to_readable_dict(self):
742
"""Turn the holder info into a dict of human-readable attributes.
744
For example, the start time is presented relative to the current time,
745
rather than as seconds since the epoch.
747
Returns a list of [user, hostname, pid, time_ago] all as readable
750
start_time = self.info_dict.get('start_time')
751
if start_time is None:
752
time_ago = '(unknown)'
754
time_ago = format_delta(
755
time.time() - int(self.info_dict['start_time']))
756
user = self.info_dict.get('user', '<unknown>')
757
hostname = self.info_dict.get('hostname', '<unknown>')
758
pid = self.info_dict.get('pid', '<unknown>')
765
def get(self, field_name):
766
"""Return the contents of a field from the lock info, or None."""
767
return self.info_dict.get(field_name)
770
def for_this_process(cls, extra_holder_info):
771
"""Return a new LockHeldInfo for a lock taken by this process.
774
hostname=get_host_name(),
775
pid=str(os.getpid()),
776
nonce=rand_chars(20),
777
start_time=str(int(time.time())),
778
user=get_username_for_lock_info(),
780
if extra_holder_info is not None:
781
info.update(extra_holder_info)
785
s = rio.Stanza(**self.info_dict)
789
def from_info_file_bytes(cls, info_file_bytes):
790
"""Construct from the contents of the held file."""
791
lines = osutils.split_lines(info_file_bytes)
793
stanza = rio.read_stanza(lines)
794
except ValueError, e:
795
mutter('Corrupt lock info file: %r', lines)
796
raise LockCorrupt("could not parse lock info file: " + str(e),
799
# see bug 185013; we fairly often end up with the info file being
800
# empty after an interruption; we could log a message here but
801
# there may not be much we can say
804
return cls(stanza.as_dict())
806
def __cmp__(self, other):
807
"""Value comparison of lock holders."""
809
cmp(type(self), type(other))
810
or cmp(self.info_dict, other.info_dict))
812
def is_locked_by_this_process(self):
813
"""True if this process seems to be the current lock holder."""
815
self.get('hostname') == get_host_name()
816
and self.get('pid') == str(os.getpid())
817
and self.get('user') == get_username_for_lock_info())
819
def is_lock_holder_known_dead(self):
820
"""True if the lock holder process is known to be dead.
822
False if it's either known to be still alive, or if we just can't tell.
824
We can be fairly sure the lock holder is dead if it declared the same
825
hostname and there is no process with the given pid alive. If people
826
have multiple machines with the same hostname this may cause trouble.
828
This doesn't check whether the lock holder is in fact the same process
829
calling this method. (In that case it will return true.)
831
if self.get('hostname') != get_host_name():
833
if self.get('hostname') == 'localhost':
836
if self.get('user') != get_username_for_lock_info():
837
# Could well be another local process by a different user, but
838
# just to be safe we won't conclude about this either.
840
pid_str = self.info_dict.get('pid', None)
842
mutter("no pid recorded in %r" % (self, ))
847
mutter("can't parse pid %r from %r"
850
return osutils.is_local_pid_dead(pid)
853
def get_username_for_lock_info():
854
"""Get a username suitable for putting into a lock.
856
It's ok if what's written here is not a proper email address as long
857
as it gives some clue who the user is.
860
return config.GlobalConfig().username()
861
except errors.NoWhoami:
862
return osutils.getuser_unicode()
added
removed
bzrlib/lockdir.py
