223
237
except (errors.TransportError, PathError), e:
224
238
self._trace("... failed to create pending dir, %s", e)
225
239
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)
242
self.transport.rename(tmpname, self._held_dir)
244
except (errors.TransportError, PathError, DirectoryNotEmpty,
245
FileExists, ResourceBusy), e:
246
self._trace("... contention, %s", e)
247
other_holder = self.peek()
248
self._trace("other holder is %r" % other_holder)
250
self._handle_lock_contention(other_holder)
252
self._remove_pending_dir(tmpname)
255
self._trace("... lock failed, %s", e)
256
self._remove_pending_dir(tmpname)
237
258
# We must check we really got the lock, because Launchpad's sftp
238
259
# server at one time had a bug were the rename would successfully
239
260
# move the new directory into the existing directory, which was
240
261
# incorrect. It's possible some other servers or filesystems will
241
262
# have a similar bug allowing someone to think they got the lock
242
263
# when it's already held.
265
# See <https://bugs.launchpad.net/bzr/+bug/498378> for one case.
267
# Strictly the check is unnecessary and a waste of time for most
268
# people, but probably worth trapping if something is wrong.
243
269
info = self.peek()
244
270
self._trace("after locking, info=%r", info)
245
if info['nonce'] != self.nonce:
272
raise LockFailed(self, "lock was renamed into place, but "
274
if info.get('nonce') != self.nonce:
246
275
self._trace("rename succeeded, "
247
276
"but lock is still held by someone else")
248
277
raise LockContention(self)
251
280
(time.time() - start_time) * 1000)
252
281
return self.nonce
283
def _handle_lock_contention(self, other_holder):
284
"""A lock we want to take is held by someone else.
286
This function can: tell the user about it; possibly detect that it's
287
safe or appropriate to steal the lock, or just raise an exception.
289
If this function returns (without raising an exception) the lock will
292
:param other_holder: A LockHeldInfo for the current holder; note that
293
it might be None if the lock can be seen to be held but the info
296
if (other_holder is not None):
297
if other_holder.is_lock_holder_known_dead():
298
if self.get_config().get_user_option_as_bool(
301
ui.ui_factory.show_user_warning(
303
lock_url=urlutils.join(self.transport.base, self.path),
304
other_holder_info=unicode(other_holder))
305
self.force_break(other_holder)
306
self._trace("stole lock from dead holder")
308
raise LockContention(self)
254
310
def _remove_pending_dir(self, tmpname):
255
311
"""Remove the pending directory
332
389
def break_lock(self):
333
390
"""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
392
This is a UI centric function: it uses the ui.ui_factory to
336
393
prompt for input if a lock is detected and there is any doubt about
337
it possibly being still active.
394
it possibly being still active. force_break is the non-interactive
397
:returns: LockResult for the broken lock.
339
399
self._check_not_locked()
340
holder_info = self.peek()
401
holder_info = self.peek()
402
except LockCorrupt, e:
403
# The lock info is corrupt.
404
if ui.ui_factory.get_boolean(u"Break (corrupt %r)" % (self,)):
405
self.force_break_corrupt(e.file_data)
341
407
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)
408
if ui.ui_factory.confirm_action(
409
u"Break %(lock_info)s",
410
'bzrlib.lockdir.break',
411
dict(lock_info=unicode(holder_info))):
412
result = self.force_break(holder_info)
413
ui.ui_factory.show_message(
414
"Broke lock %s" % result.lock_url)
346
416
def force_break(self, dead_holder_info):
347
417
"""Release a lock held by another process.
350
420
it still thinks it has the lock there will be two concurrent writers.
351
421
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
423
After the lock is broken it will not be held by any process.
359
424
It is possible that another process may sneak in and take the
360
425
lock before the breaking process acquires it.
427
:param dead_holder_info:
428
Must be the result of a previous LockDir.peek() call; this is used
429
to check that it's still held by the same process that the user
430
decided was dead. If this is not the current holder,
431
LockBreakMismatch is raised.
433
:returns: LockResult for the broken lock.
362
if not isinstance(dead_holder_info, dict):
435
if not isinstance(dead_holder_info, LockHeldInfo):
363
436
raise ValueError("dead_holder_info: %r" % dead_holder_info)
364
437
self._check_not_locked()
365
438
current_info = self.peek()
383
456
current_info.get('nonce'))
384
457
for hook in self.hooks['lock_broken']:
461
def force_break_corrupt(self, corrupt_info_lines):
462
"""Release a lock that has been corrupted.
464
This is very similar to force_break, it except it doesn't assume that
465
self.peek() can work.
467
:param corrupt_info_lines: the lines of the corrupted info file, used
468
to check that the lock hasn't changed between reading the (corrupt)
469
info file and calling force_break_corrupt.
471
# XXX: this copes with unparseable info files, but what about missing
472
# info files? Or missing lock dirs?
473
self._check_not_locked()
474
tmpname = '%s/broken.%s.tmp' % (self.path, rand_chars(20))
475
self.transport.rename(self._held_dir, tmpname)
476
# check that we actually broke the right lock, not someone else;
477
# there's a small race window between checking it and doing the
479
broken_info_path = tmpname + self.__INFO_NAME
480
broken_content = self.transport.get_bytes(broken_info_path)
481
broken_lines = osutils.split_lines(broken_content)
482
if broken_lines != corrupt_info_lines:
483
raise LockBreakMismatch(self, broken_lines, corrupt_info_lines)
484
self.transport.delete(broken_info_path)
485
self.transport.rmdir(tmpname)
486
result = lock.LockResult(self.transport.abspath(self.path))
487
for hook in self.hooks['lock_broken']:
387
490
def _check_not_locked(self):
388
491
"""If the lock is held by this instance, raise an error."""
518
618
start = 'Lock owner changed for'
519
619
last_info = new_info
520
formatted_info = self._format_lock_info(new_info)
620
msg = u'%s lock %s %s.' % (start, lock_url, new_info)
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 += ('\nWill continue to try until %s, unless '
628
msg += '\nSee "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
return config.GlobalConfig()
715
class LockHeldInfo(object):
716
"""The information recorded about a held lock.
718
This information is recorded into the lock when it's taken, and it can be
719
read back by any process with access to the lockdir. It can be used, for
720
example, to tell the user who holds the lock, or to try to detect whether
721
the lock holder is still alive.
723
Prior to bzr 2.4 a simple dict was used instead of an object.
726
def __init__(self, info_dict):
727
self.info_dict = info_dict
730
"""Return a debugging representation of this object."""
731
return "%s(%r)" % (self.__class__.__name__, self.info_dict)
733
def __unicode__(self):
734
"""Return a user-oriented description of this object."""
735
d = self.to_readable_dict()
737
u'held by %(user)s on %(hostname)s (process #%(pid)s), '
738
u'acquired %(time_ago)s' % d)
740
def to_readable_dict(self):
741
"""Turn the holder info into a dict of human-readable attributes.
743
For example, the start time is presented relative to the current time,
744
rather than as seconds since the epoch.
746
Returns a list of [user, hostname, pid, time_ago] all as readable
749
start_time = self.info_dict.get('start_time')
750
if start_time is None:
751
time_ago = '(unknown)'
753
time_ago = format_delta(
754
time.time() - int(self.info_dict['start_time']))
755
user = self.info_dict.get('user', '<unknown>')
756
hostname = self.info_dict.get('hostname', '<unknown>')
757
pid = self.info_dict.get('pid', '<unknown>')
764
def get(self, field_name):
765
"""Return the contents of a field from the lock info, or None."""
766
return self.info_dict.get(field_name)
769
def for_this_process(cls, extra_holder_info):
770
"""Return a new LockHeldInfo for a lock taken by this process.
773
hostname=get_host_name(),
774
pid=str(os.getpid()),
775
nonce=rand_chars(20),
776
start_time=str(int(time.time())),
777
user=get_username_for_lock_info(),
779
if extra_holder_info is not None:
780
info.update(extra_holder_info)
784
s = rio.Stanza(**self.info_dict)
788
def from_info_file_bytes(cls, info_file_bytes):
789
"""Construct from the contents of the held file."""
790
lines = osutils.split_lines(info_file_bytes)
792
stanza = rio.read_stanza(lines)
793
except ValueError, e:
794
mutter('Corrupt lock info file: %r', lines)
795
raise LockCorrupt("could not parse lock info file: " + str(e),
798
# see bug 185013; we fairly often end up with the info file being
799
# empty after an interruption; we could log a message here but
800
# there may not be much we can say
803
return cls(stanza.as_dict())
805
def __cmp__(self, other):
806
"""Value comparison of lock holders."""
808
cmp(type(self), type(other))
809
or cmp(self.info_dict, other.info_dict))
811
def is_locked_by_this_process(self):
812
"""True if this process seems to be the current lock holder."""
814
self.get('hostname') == get_host_name()
815
and self.get('pid') == str(os.getpid())
816
and self.get('user') == get_username_for_lock_info())
818
def is_lock_holder_known_dead(self):
819
"""True if the lock holder process is known to be dead.
821
False if it's either known to be still alive, or if we just can't tell.
823
We can be fairly sure the lock holder is dead if it declared the same
824
hostname and there is no process with the given pid alive. If people
825
have multiple machines with the same hostname this may cause trouble.
827
This doesn't check whether the lock holder is in fact the same process
828
calling this method. (In that case it will return true.)
830
if self.get('hostname') != get_host_name():
832
if self.get('hostname') == 'localhost':
835
if self.get('user') != get_username_for_lock_info():
836
# Could well be another local process by a different user, but
837
# just to be safe we won't conclude about this either.
839
pid_str = self.info_dict.get('pid', None)
841
mutter("no pid recorded in %r" % (self, ))
846
mutter("can't parse pid %r from %r"
849
return osutils.is_local_pid_dead(pid)
852
def get_username_for_lock_info():
853
"""Get a username suitable for putting into a lock.
855
It's ok if what's written here is not a proper email address as long
856
as it gives some clue who the user is.
859
return config.GlobalConfig().username()
860
except errors.NoWhoami:
861
return osutils.getuser_unicode()
added
removed
bzrlib/lockdir.py
