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#
# This file is part of Checkbox.
#
# Copyright 2008 Canonical Ltd.
#
# Checkbox is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3,
# as published by the Free Software Foundation.
#
# Checkbox is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Checkbox. If not, see <http://www.gnu.org/licenses/>.
#
import os
import fcntl
import posixpath
import signal
import logging
from time import time
from gettext import gettext as _
from checkbox.contrib.glock import GlobalLock, LockAlreadyAcquired
from checkbox.lib.safe import safe_make_directory
from checkbox.properties import Int, Path
from checkbox.plugin import Plugin
class LockPrompt(Plugin):
# Filename where the application lock is stored.
filename = Path(default="%(checkbox_data)s/lock")
# Timeout after which to show an error prompt.
timeout = Int(default=0)
logger = logging.getLogger()
def register(self, manager):
super(LockPrompt, self).register(manager)
self._lock = None
self._fd = None
self._manager.reactor.call_on(
"prompt-begin", self.prompt_begin, -1000)
self._manager.reactor.call_on("stop", self.release, 1000)
def prompt_begin(self, interface):
directory = posixpath.dirname(self.filename)
safe_make_directory(directory)
# Try to lock the process
self._lock = GlobalLock(self.filename, logger=self.logger)
try:
self._lock.acquire()
except LockAlreadyAcquired:
if time() - os.stat(self.filename).st_atime > self.timeout:
self._manager.reactor.fire("prompt-error", interface,
_("There is another checkbox running. Please close it first."))
self._manager.reactor.stop_all()
# Stop the process if the lock is deleted
def handler(signum, frame):
if not posixpath.exists(self.filename):
self._manager.reactor.stop_all()
signal.signal(signal.SIGIO, handler)
self._fd = os.open(directory, os.O_RDONLY)
fcntl.fcntl(self._fd, fcntl.F_SETSIG, 0)
fcntl.fcntl(self._fd, fcntl.F_NOTIFY, fcntl.DN_DELETE|fcntl.DN_MULTISHOT)
def release(self):
# Properly release to the lock
self._lock.release(skip_delete=True)
os.close(self._fd)
os.unlink(self.filename)
factory = LockPrompt
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