flock_tool.py 文件源码

def ExecFlock(self, lockfile, *cmd_list):
    """Emulates the most basic behavior of Linux's flock(1)."""
    # Rely on exception handling to report errors.
    # Note that the stock python on SunOS has a bug
    # where fcntl.flock(fd, LOCK_EX) always fails
    # with EBADF, that's why we use this F_SETLK
    # hack instead.
    fd = os.open(lockfile, os.O_WRONLY|os.O_NOCTTY|os.O_CREAT, 0666)
    if sys.platform.startswith('aix'):
      # Python on AIX is compiled with LARGEFILE support, which changes the
      # struct size.
      op = struct.pack('hhIllqq', fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
    else:
      op = struct.pack('hhllhhl', fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
    fcntl.fcntl(fd, fcntl.F_SETLK, op)
    return subprocess.call(cmd_list)