def testCanUnlock(self):
"""Test that we release locks correctly."""
lock_path = os.path.join(self.tempdir, 'locked_file')
with locking.PortableLinkLock(lock_path, max_retry=0):
pass
with locking.PortableLinkLock(lock_path, max_retry=0):
pass
def testLockExclusivity(self):
"""Test that when we have a lock, someone else can't grab it."""
lock_path = os.path.join(self.tempdir, 'locked_file')
with locking.PortableLinkLock(lock_path, max_retry=0):
with self.assertRaises(locking.LockNotAcquiredError):
with locking.PortableLinkLock(lock_path,
max_retry=5,
sleep=0.1):
self.fail('We acquired a lock twice?')
def AddUser(self, user):
"""Atomically add a user to the database.
If a user named |user.user| already exists, this method will simply return.
Args:
user: user_db.User object to add to database.
"""
# Try to avoid grabbing the lock in the common case that a user already
# exists.
if self.UserExists(user.user):
logging.info(
'Not installing user "%s" because it already existed.',
user.user)
return
# Clear the user cache to force ourselves to reparse.
self._user_cache = None
with locking.PortableLinkLock(self._user_db_file + '.lock',
max_retry=self._DB_LOCK_RETRIES):
# Check that |user| exists under the lock in case we're racing to create
# this user.
if self.UserExists(user.user):
logging.info(
'Not installing user "%s" because it already existed.',
user.user)
return
self._users[user.user] = user
new_users = sorted(self._users.itervalues(), key=lambda u: u.uid)
contents = '\n'.join([UserToEntry(u) for u in new_users])
osutils.WriteFile(self._user_db_file,
contents,
atomic=True,
sudo=True)
print('Added user "%s" to %s:' % (user.user, self._user_db_file))
print(' - password entry: %s' % user.password)
print(' - id: %d' % user.uid)
print(' - group id: %d' % user.gid)
print(' - gecos: %s' % user.gecos)
print(' - home: %s' % user.home)
print(' - shell: %s' % user.shell)
def AddGroup(self, group):
"""Atomically add a group to the database.
If a group named |group.group| already exists, this method will simply
return.
Args:
group: user_db.Group object to add to database.
"""
# Try to avoid grabbing the lock in the common case that a group already
# exists.
if self.GroupExists(group.group):
logging.info(
'Not installing group "%s" because it already existed.',
group.group)
return
# Clear the group cache to force ourselves to reparse.
self._group_cache = None
with locking.PortableLinkLock(self._group_db_file + '.lock',
max_retry=self._DB_LOCK_RETRIES):
# Check that |group| exists under the lock in case we're racing to create
# this group.
if self.GroupExists(group.group):
logging.info(
'Not installing group "%s" because it already existed.',
group.group)
return
self._groups[group.group] = group
new_groups = sorted(self._groups.itervalues(), key=lambda g: g.gid)
contents = '\n'.join([GroupToEntry(g) for g in new_groups])
osutils.WriteFile(self._group_db_file,
contents,
atomic=True,
sudo=True)
print('Added group "%s" to %s:' %
(group.group, self._group_db_file))
print(' - group id: %d' % group.gid)
print(' - password entry: %s' % group.password)
print(' - user list: %s' % ','.join(group.users))
def GetGroupEntry(self, groupname, skip_lock=False):
"""Returns a group's database entry.
Args:
groupname: name of group to get the entry for.
skip_lock: True iff we should skip getting a lock before reading the
database.
Returns:
database entry as a string.
"""
if skip_lock:
return GroupToEntry(self._groups[groupname])
# Clear the group cache to force ourselves to reparse while holding a lock.
self._group_cache = None
with locking.PortableLinkLock(self._group_db_file + '.lock',
max_retry=self._DB_LOCK_RETRIES):
return GroupToEntry(self._groups[groupname])
def GetUserEntry(self, username, skip_lock=False):
"""Returns a user's database entry.
Args:
username: name of user to get the entry for.
skip_lock: True iff we should skip getting a lock before reading the
database.
Returns:
database entry as a string.
"""
if skip_lock:
return UserToEntry(self._users[username])
# Clear the user cache to force ourselves to reparse while holding a lock.
self._user_cache = None
with locking.PortableLinkLock(self._user_db_file + '.lock',
max_retry=self._DB_LOCK_RETRIES):
return UserToEntry(self._users[username])
