1 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 import logging 6 import os 7 import pipes 8 import threading 9 10 from autotest_lib.client.common_lib import error 11 12 class _HelperThread(threading.Thread): 13 """Make a thread to run the command in.""" 14 def __init__(self, host, cmd): 15 super(_HelperThread, self).__init__() 16 self._host = host 17 self._cmd = cmd 18 self._result = None 19 self.daemon = True 20 21 22 def run(self): 23 logging.info('Helper thread running: %s', self._cmd) 24 # NB: set ignore_status as we're always terminated w/ pkill 25 self._result = self._host.run(self._cmd, ignore_status=True) 26 27 28 @property 29 def result(self): 30 """ 31 @returns string result of running our command if the command has 32 finished, and None otherwise. 33 34 """ 35 return self._result 36 37 38 class Command(object): 39 """ 40 Encapsulates a command run on a remote machine. 41 42 Future work is to have this get the PID (by prepending 'echo $$; 43 exec' to the command and parsing the output). 44 45 """ 46 def __init__(self, host, cmd, pkill_argument=None): 47 """ 48 Run a command on a remote host in the background. 49 50 @param host Host object representing the remote machine. 51 @param cmd String command to run on the remote machine. 52 @param pkill_argument String argument to pkill to kill the remote 53 process. 54 55 """ 56 if pkill_argument is None: 57 # Attempt to guess what a suitable pkill argument would look like. 58 pkill_argument = os.path.basename(cmd.split()[0]) 59 self._command_name = pipes.quote(pkill_argument) 60 self._host = host 61 self._thread = _HelperThread(self._host, cmd) 62 self._thread.start() 63 64 65 def join(self, signal=None, timeout=5.0): 66 """ 67 Kills the remote command and waits until it dies. Takes an optional 68 signal argument to control which signal to send the process to be 69 killed. 70 71 @param signal Signal string to give to pkill (e.g. SIGNAL_INT). 72 @param timeout float number of seconds to wait for join to finish. 73 74 """ 75 if signal is None: 76 signal_arg = '' 77 else: 78 # In theory, it should be hard to pass something evil for signal if 79 # we make sure it's an integer before passing it to pkill. 80 signal_arg = '-' + str(int(signal)) 81 82 # Ignore status because the command may have exited already 83 self._host.run("pkill %s %s" % (signal_arg, self._command_name), 84 ignore_status=True) 85 self._thread.join(timeout) 86 if self._thread.isAlive(): 87 raise error.TestFail('Failed to kill remote command: %s' % 88 self._command_name) 89 90 91 def __enter__(self): 92 return self 93 94 95 def __exit__(self, exception, value, traceback): 96 self.join() 97 return False 98 99 100 @property 101 def result(self): 102 """ 103 @returns string result of running our command if the command has 104 finished, and None otherwise. 105 106 """ 107 return self._thread.result 108
