Locks apt* tools until closed.

apt_lock.py

#!/usr/bin/env python
# -- Content-Encoding: UTF-8 --
"""
Locks apt until closed
"""

from __future__ import print_function
import time
import signal
import sys

try:
    import fcntl
except ImportError:
    print("Works only on *nix")
    sys.exit(1)


def signal_handler(fd, signum):
    """
    Handles signals
    """
    print("Got signal", signum, ": unlocking.")
    fcntl.lockf(fd, fcntl.LOCK_UN)
    sys.exit(128)


def main():
    """
    Entry point
    """
    try:
        with open("/var/lib/apt/lists/lock", "w+") as fd:
            # Register signal handlers
            handler = lambda s, f: signal_handler(fd, s)
            signal.signal(signal.SIGSEGV, handler)
            signal.signal(signal.SIGTERM, handler)

            try:
                fcntl.lockf(fd, fcntl.LOCK_EX)
                print("Locked...")
                while True:
                    time.sleep(1)
            except KeyboardInterrupt:
                print("Got Ctrl+C")
            finally:
                fcntl.lockf(fd, fcntl.LOCK_UN)
                print("Unlocked.")
    except IOError as ex:
        print("Error locking file:", ex)
        return 1


if __name__ == '__main__':
    sys.exit(main() or 0)