224
238
except (errors.TransportError, PathError), e:
225
239
self._trace("... failed to create pending dir, %s", e)
226
240
raise LockFailed(self, e)
228
self.transport.rename(tmpname, self._held_dir)
229
except (errors.TransportError, PathError, DirectoryNotEmpty,
230
FileExists, ResourceBusy), e:
231
self._trace("... contention, %s", e)
232
self._remove_pending_dir(tmpname)
233
raise LockContention(self)
235
self._trace("... lock failed, %s", e)
236
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)
238
259
# We must check we really got the lock, because Launchpad's sftp
239
260
# server at one time had a bug were the rename would successfully
240
261
# move the new directory into the existing directory, which was
241
262
# incorrect. It's possible some other servers or filesystems will
242
263
# have a similar bug allowing someone to think they got the lock
243
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.
244
270
info = self.peek()
245
271
self._trace("after locking, info=%r", info)
246
if info['nonce'] != self.nonce:
273
raise LockFailed(self, "lock was renamed into place, but "
275
if info.get('nonce') != self.nonce:
247
276
self._trace("rename succeeded, "
248
277
"but lock is still held by someone else")
249
278
raise LockContention(self)
252
281
(time.time() - start_time) * 1000)
253
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)
255
309
def _remove_pending_dir(self, tmpname):
256
310
"""Remove the pending directory
258
This is called if we failed to rename into place, so that the pending
312
This is called if we failed to rename into place, so that the pending
259
313
dirs don't clutter up the lockdir.
261
315
self._trace("remove %s", tmpname)
326
381
self._trace("... unlock succeeded after %dms",
327
382
(time.time() - start_time) * 1000)
328
383
result = lock.LockResult(self.transport.abspath(self.path),
330
385
for hook in self.hooks['lock_released']:
333
388
def break_lock(self):
334
389
"""Break a lock not held by this instance of LockDir.
336
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
337
392
prompt for input if a lock is detected and there is any doubt about
338
it possibly being still active.
393
it possibly being still active. force_break is the non-interactive
396
:returns: LockResult for the broken lock.
340
398
self._check_not_locked()
341
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)
342
406
if holder_info is not None:
343
lock_info = '\n'.join(self._format_lock_info(holder_info))
344
if bzrlib.ui.ui_factory.get_boolean("Break %s" % lock_info):
345
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)
347
415
def force_break(self, dead_holder_info):
348
416
"""Release a lock held by another process.
351
419
it still thinks it has the lock there will be two concurrent writers.
352
420
In general the user's approval should be sought for lock breaks.
354
dead_holder_info must be the result of a previous LockDir.peek() call;
355
this is used to check that it's still held by the same process that
356
the user decided was dead. If this is not the current holder,
357
LockBreakMismatch is raised.
359
422
After the lock is broken it will not be held by any process.
360
It is possible that another process may sneak in and take the
423
It is possible that another process may sneak in and take the
361
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.
363
if not isinstance(dead_holder_info, dict):
434
if not isinstance(dead_holder_info, LockHeldInfo):
364
435
raise ValueError("dead_holder_info: %r" % dead_holder_info)
365
436
self._check_not_locked()
366
437
current_info = self.peek()
380
451
raise LockBreakMismatch(self, broken_info, dead_holder_info)
381
452
self.transport.delete(broken_info_path)
382
453
self.transport.rmdir(tmpname)
454
result = lock.LockResult(self.transport.abspath(self.path),
455
current_info.get('nonce'))
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']:
384
489
def _check_not_locked(self):
385
490
"""If the lock is held by this instance, raise an error."""
510
612
new_info = self.peek()
511
613
if new_info is not None and new_info != last_info:
512
614
if last_info is None:
513
start = 'Unable to obtain'
615
start = gettext('Unable to obtain')
515
start = 'Lock owner changed for'
617
start = gettext('Lock owner changed for')
516
618
last_info = new_info
517
formatted_info = self._format_lock_info(new_info)
619
msg = gettext('{0} lock {1} {2}.').format(start, lock_url,
518
621
if deadline_str is None:
519
622
deadline_str = time.strftime('%H:%M:%S',
520
time.localtime(deadline))
521
lock_url = self.transport.abspath(self.path)
522
self._report_function('%s %s\n'
524
'%s\n' # locked ... ago
525
'Will continue to try until %s, unless '
527
'If you\'re sure that it\'s not being '
528
'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)
536
630
if (max_attempts is not None) and (attempt_count >= max_attempts):
537
631
self._trace("exceeded %d attempts")
538
632
raise LockContention(self)
578
675
def lock_read(self):
579
676
"""Compatibility-mode shared lock.
581
LockDir doesn't support shared read-only locks, so this
678
LockDir doesn't support shared read-only locks, so this
582
679
just pretends that the lock is taken but really does nothing.
584
# At the moment Branches are commonly locked for read, but
681
# At the moment Branches are commonly locked for read, but
585
682
# we can't rely on that remotely. Once this is cleaned up,
586
# reenable this warning to prevent it coming back in
683
# reenable this warning to prevent it coming back in
587
684
# -- mbp 20060303
588
685
## warn("LockDir.lock_read falls back to write lock")
589
686
if self._lock_held or self._fake_read_lock:
590
687
raise LockContention(self)
591
688
self._fake_read_lock = True
593
def _format_lock_info(self, info):
594
"""Turn the contents of peek() into something for the user"""
595
lock_url = self.transport.abspath(self.path)
596
delta = time.time() - int(info['start_time'])
598
'lock %s' % (lock_url,),
599
'held by %(user)s on host %(hostname)s [process #%(pid)s]' % info,
600
'locked %s' % (format_delta(delta),),
603
690
def validate_token(self, token):
604
691
if token is not None:
605
692
info = self.peek()
617
704
if 'lock' not in debug.debug_flags:
619
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
