237
225
except (errors.TransportError, PathError), e:
238
226
self._trace("... failed to create pending dir, %s", e)
239
227
raise LockFailed(self, e)
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)
229
self.transport.rename(tmpname, self._held_dir)
230
except (errors.TransportError, PathError, DirectoryNotEmpty,
231
FileExists, ResourceBusy), e:
232
self._trace("... contention, %s", e)
233
self._remove_pending_dir(tmpname)
234
raise LockContention(self)
236
self._trace("... lock failed, %s", e)
237
self._remove_pending_dir(tmpname)
258
239
# We must check we really got the lock, because Launchpad's sftp
259
240
# server at one time had a bug were the rename would successfully
260
241
# move the new directory into the existing directory, which was
261
242
# incorrect. It's possible some other servers or filesystems will
262
243
# have a similar bug allowing someone to think they got the lock
263
244
# 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.
269
245
info = self.peek()
270
246
self._trace("after locking, info=%r", info)
272
raise LockFailed(self, "lock was renamed into place, but "
274
if info.get('nonce') != self.nonce:
247
if info['nonce'] != self.nonce:
275
248
self._trace("rename succeeded, "
276
249
"but lock is still held by someone else")
277
250
raise LockContention(self)
280
253
(time.time() - start_time) * 1000)
281
254
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('locks.steal_dead'):
299
ui.ui_factory.show_user_warning(
301
lock_url=urlutils.join(self.transport.base, self.path),
302
other_holder_info=unicode(other_holder))
303
self.force_break(other_holder)
304
self._trace("stole lock from dead holder")
306
raise LockContention(self)
308
256
def _remove_pending_dir(self, tmpname):
309
257
"""Remove the pending directory
387
335
def break_lock(self):
388
336
"""Break a lock not held by this instance of LockDir.
390
This is a UI centric function: it uses the ui.ui_factory to
338
This is a UI centric function: it uses the bzrlib.ui.ui_factory to
391
339
prompt for input if a lock is detected and there is any doubt about
392
it possibly being still active. force_break is the non-interactive
395
:returns: LockResult for the broken lock.
340
it possibly being still active.
397
342
self._check_not_locked()
399
holder_info = self.peek()
400
except LockCorrupt, e:
401
# The lock info is corrupt.
402
if ui.ui_factory.get_boolean(u"Break (corrupt %r)" % (self,)):
403
self.force_break_corrupt(e.file_data)
343
holder_info = self.peek()
405
344
if holder_info is not None:
406
if ui.ui_factory.confirm_action(
407
u"Break %(lock_info)s",
408
'bzrlib.lockdir.break',
409
dict(lock_info=unicode(holder_info))):
410
result = self.force_break(holder_info)
411
ui.ui_factory.show_message(
412
"Broke lock %s" % result.lock_url)
345
lock_info = '\n'.join(self._format_lock_info(holder_info))
346
if bzrlib.ui.ui_factory.get_boolean("Break %s" % lock_info):
347
self.force_break(holder_info)
414
349
def force_break(self, dead_holder_info):
415
350
"""Release a lock held by another process.
418
353
it still thinks it has the lock there will be two concurrent writers.
419
354
In general the user's approval should be sought for lock breaks.
356
dead_holder_info must be the result of a previous LockDir.peek() call;
357
this is used to check that it's still held by the same process that
358
the user decided was dead. If this is not the current holder,
359
LockBreakMismatch is raised.
421
361
After the lock is broken it will not be held by any process.
422
362
It is possible that another process may sneak in and take the
423
363
lock before the breaking process acquires it.
425
:param dead_holder_info:
426
Must be the result of a previous LockDir.peek() call; this is used
427
to check that it's still held by the same process that the user
428
decided was dead. If this is not the current holder,
429
LockBreakMismatch is raised.
431
:returns: LockResult for the broken lock.
433
if not isinstance(dead_holder_info, LockHeldInfo):
365
if not isinstance(dead_holder_info, dict):
434
366
raise ValueError("dead_holder_info: %r" % dead_holder_info)
435
367
self._check_not_locked()
436
368
current_info = self.peek()
454
386
current_info.get('nonce'))
455
387
for hook in self.hooks['lock_broken']:
459
def force_break_corrupt(self, corrupt_info_lines):
460
"""Release a lock that has been corrupted.
462
This is very similar to force_break, it except it doesn't assume that
463
self.peek() can work.
465
:param corrupt_info_lines: the lines of the corrupted info file, used
466
to check that the lock hasn't changed between reading the (corrupt)
467
info file and calling force_break_corrupt.
469
# XXX: this copes with unparseable info files, but what about missing
470
# info files? Or missing lock dirs?
471
self._check_not_locked()
472
tmpname = '%s/broken.%s.tmp' % (self.path, rand_chars(20))
473
self.transport.rename(self._held_dir, tmpname)
474
# check that we actually broke the right lock, not someone else;
475
# there's a small race window between checking it and doing the
477
broken_info_path = tmpname + self.__INFO_NAME
478
broken_content = self.transport.get_bytes(broken_info_path)
479
broken_lines = osutils.split_lines(broken_content)
480
if broken_lines != corrupt_info_lines:
481
raise LockBreakMismatch(self, broken_lines, corrupt_info_lines)
482
self.transport.delete(broken_info_path)
483
self.transport.rmdir(tmpname)
484
result = lock.LockResult(self.transport.abspath(self.path))
485
for hook in self.hooks['lock_broken']:
488
390
def _check_not_locked(self):
489
391
"""If the lock is held by this instance, raise an error."""
616
522
start = 'Lock owner changed for'
617
523
last_info = new_info
618
msg = u'%s lock %s %s.' % (start, lock_url, new_info)
524
formatted_info = self._format_lock_info(new_info)
619
525
if deadline_str is None:
620
526
deadline_str = time.strftime('%H:%M:%S',
621
time.localtime(deadline))
623
msg += ('\nWill continue to try until %s, unless '
626
msg += '\nSee "bzr help break-lock" for more.'
627
self._report_function(msg)
527
time.localtime(deadline))
528
lock_url = self.transport.abspath(self.path)
529
self._report_function('%s %s\n'
531
'%s\n' # locked ... ago
532
'Will continue to try until %s, unless '
534
'If you\'re sure that it\'s not being '
535
'modified, use bzr break-lock %s',
628
543
if (max_attempts is not None) and (attempt_count >= max_attempts):
629
544
self._trace("exceeded %d attempts")
630
545
raise LockContention(self)
702
624
if 'lock' not in debug.debug_flags:
704
626
mutter(str(self) + ": " + (format % args))
706
def get_config(self):
707
"""Get the configuration that governs this lockdir."""
708
# XXX: This really should also use the locationconfig at least, but
709
# that seems a bit hard to hook up at the moment. -- mbp 20110329
710
# FIXME: The above is still true ;) -- vila 20110811
711
return config.GlobalStack()
714
class LockHeldInfo(object):
715
"""The information recorded about a held lock.
717
This information is recorded into the lock when it's taken, and it can be
718
read back by any process with access to the lockdir. It can be used, for
719
example, to tell the user who holds the lock, or to try to detect whether
720
the lock holder is still alive.
722
Prior to bzr 2.4 a simple dict was used instead of an object.
725
def __init__(self, info_dict):
726
self.info_dict = info_dict
729
"""Return a debugging representation of this object."""
730
return "%s(%r)" % (self.__class__.__name__, self.info_dict)
732
def __unicode__(self):
733
"""Return a user-oriented description of this object."""
734
d = self.to_readable_dict()
736
u'held by %(user)s on %(hostname)s (process #%(pid)s), '
737
u'acquired %(time_ago)s' % d)
739
def to_readable_dict(self):
740
"""Turn the holder info into a dict of human-readable attributes.
742
For example, the start time is presented relative to the current time,
743
rather than as seconds since the epoch.
745
Returns a list of [user, hostname, pid, time_ago] all as readable
748
start_time = self.info_dict.get('start_time')
749
if start_time is None:
750
time_ago = '(unknown)'
752
time_ago = format_delta(
753
time.time() - int(self.info_dict['start_time']))
754
user = self.info_dict.get('user', '<unknown>')
755
hostname = self.info_dict.get('hostname', '<unknown>')
756
pid = self.info_dict.get('pid', '<unknown>')
763
def get(self, field_name):
764
"""Return the contents of a field from the lock info, or None."""
765
return self.info_dict.get(field_name)
768
def for_this_process(cls, extra_holder_info):
769
"""Return a new LockHeldInfo for a lock taken by this process.
772
hostname=get_host_name(),
773
pid=str(os.getpid()),
774
nonce=rand_chars(20),
775
start_time=str(int(time.time())),
776
user=get_username_for_lock_info(),
778
if extra_holder_info is not None:
779
info.update(extra_holder_info)
783
s = rio.Stanza(**self.info_dict)
787
def from_info_file_bytes(cls, info_file_bytes):
788
"""Construct from the contents of the held file."""
789
lines = osutils.split_lines(info_file_bytes)
791
stanza = rio.read_stanza(lines)
792
except ValueError, e:
793
mutter('Corrupt lock info file: %r', lines)
794
raise LockCorrupt("could not parse lock info file: " + str(e),
797
# see bug 185013; we fairly often end up with the info file being
798
# empty after an interruption; we could log a message here but
799
# there may not be much we can say
802
return cls(stanza.as_dict())
804
def __cmp__(self, other):
805
"""Value comparison of lock holders."""
807
cmp(type(self), type(other))
808
or cmp(self.info_dict, other.info_dict))
810
def is_locked_by_this_process(self):
811
"""True if this process seems to be the current lock holder."""
813
self.get('hostname') == get_host_name()
814
and self.get('pid') == str(os.getpid())
815
and self.get('user') == get_username_for_lock_info())
817
def is_lock_holder_known_dead(self):
818
"""True if the lock holder process is known to be dead.
820
False if it's either known to be still alive, or if we just can't tell.
822
We can be fairly sure the lock holder is dead if it declared the same
823
hostname and there is no process with the given pid alive. If people
824
have multiple machines with the same hostname this may cause trouble.
826
This doesn't check whether the lock holder is in fact the same process
827
calling this method. (In that case it will return true.)
829
if self.get('hostname') != get_host_name():
831
if self.get('hostname') == 'localhost':
834
if self.get('user') != get_username_for_lock_info():
835
# Could well be another local process by a different user, but
836
# just to be safe we won't conclude about this either.
838
pid_str = self.info_dict.get('pid', None)
840
mutter("no pid recorded in %r" % (self, ))
845
mutter("can't parse pid %r from %r"
848
return osutils.is_local_pid_dead(pid)
851
def get_username_for_lock_info():
852
"""Get a username suitable for putting into a lock.
854
It's ok if what's written here is not a proper email address as long
855
as it gives some clue who the user is.
858
return config.GlobalConfig().username()
859
except errors.NoWhoami:
860
return osutils.getuser_unicode()
added
removed
bzrlib/lockdir.py
