arp.py 文件源码

def run(args, output=sys.stdout, stdin=sys.stdin,
        stdin_buffer=sys.stdin.buffer):
    """Observe an Ethernet interface and print ARP bindings."""

    # First, become a progress group leader, so that signals can be directed
    # to this process and its children; see p.u.twisted.terminateProcess.
    os.setpgrp()

    network_monitor = None
    if args.input_file is None:
        if args.interface is None:
            raise ActionScriptError("Required argument: interface")
        cmd = [get_path("/usr/lib/maas/network-monitor"), args.interface]
        cmd = sudo(cmd)
        network_monitor = subprocess.Popen(
            cmd, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE)
        infile = network_monitor.stdout
    else:
        if args.input_file == '-':
            mode = os.fstat(stdin.fileno()).st_mode
            if not stat.S_ISFIFO(mode):
                raise ActionScriptError("Expected stdin to be a pipe.")
            infile = stdin_buffer
        else:
            infile = open(args.input_file, "rb")
    return_code = observe_arp_packets(
        bindings=True, verbose=args.verbose, input=infile, output=output)
    if return_code is not None:
        raise SystemExit(return_code)
    if network_monitor is not None:
        return_code = network_monitor.poll()
        if return_code is not None:
            raise SystemExit(return_code)