src/build/android/pylib/forwarder.py

   1 # Copyright (c) 2012 The Chromium 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 # pylint: disable=W0212
   6
   7 import fcntl
   8 import logging
   9 import os
  10 import psutil
  11
  12 from pylib import cmd_helper
  13 from pylib import constants
  14 from pylib import valgrind_tools
  15
  16 # TODO(jbudorick) Remove once telemetry gets switched over.
  17 import pylib.android_commands
  18 import pylib.device.device_utils
  19
  20
  21 def _GetProcessStartTime(pid):
  22   return psutil.Process(pid).create_time
  23
  24
  25 class _FileLock(object):
  26   """With statement-aware implementation of a file lock.
  27
  28   File locks are needed for cross-process synchronization when the
  29   multiprocessing Python module is used.
  30   """
  31   def __init__(self, path):
  32     self._fd = -1
  33     self._path = path
  34
  35   def __enter__(self):
  36     self._fd = os.open(self._path, os.O_RDONLY | os.O_CREAT)
  37     if self._fd < 0:
  38       raise Exception('Could not open file %s for reading' % self._path)
  39     fcntl.flock(self._fd, fcntl.LOCK_EX)
  40
  41   def __exit__(self, _exception_type, _exception_value, traceback):
  42     fcntl.flock(self._fd, fcntl.LOCK_UN)
  43     os.close(self._fd)
  44
  45
  46 class Forwarder(object):
  47   """Thread-safe class to manage port forwards from the device to the host."""
  48
  49   _DEVICE_FORWARDER_FOLDER = (constants.TEST_EXECUTABLE_DIR +
  50                               '/forwarder/')
  51   _DEVICE_FORWARDER_PATH = (constants.TEST_EXECUTABLE_DIR +
  52                             '/forwarder/device_forwarder')
  53   _LOCK_PATH = '/tmp/chrome.forwarder.lock'
  54   _MULTIPROCESSING_ENV_VAR = 'CHROME_FORWARDER_USE_MULTIPROCESSING'
  55   # Defined in host_forwarder_main.cc
  56   _HOST_FORWARDER_LOG = '/tmp/host_forwarder_log'
  57
  58   _instance = None
  59
  60   @staticmethod
  61   def UseMultiprocessing():
  62     """Tells the forwarder that multiprocessing is used."""
  63     os.environ[Forwarder._MULTIPROCESSING_ENV_VAR] = '1'
  64
  65   @staticmethod
  66   def Map(port_pairs, device, tool=None):
  67     """Runs the forwarder.
  68
  69     Args:
  70       port_pairs: A list of tuples (device_port, host_port) to forward. Note
  71                  that you can specify 0 as a device_port, in which case a
  72                  port will by dynamically assigned on the device. You can
  73                  get the number of the assigned port using the
  74                  DevicePortForHostPort method.
  75       device: A DeviceUtils instance.
  76       tool: Tool class to use to get wrapper, if necessary, for executing the
  77             forwarder (see valgrind_tools.py).
  78
  79     Raises:
  80       Exception on failure to forward the port.
  81     """
  82     # TODO(jbudorick) Remove once telemetry gets switched over.
  83     if isinstance(device, pylib.android_commands.AndroidCommands):
  84       device = pylib.device.device_utils.DeviceUtils(device)
  85     if not tool:
  86       tool = valgrind_tools.CreateTool(None, device)
  87     with _FileLock(Forwarder._LOCK_PATH):
  88       instance = Forwarder._GetInstanceLocked(tool)
  89       instance._InitDeviceLocked(device, tool)
  90
  91       device_serial = str(device)
  92       redirection_commands = [
  93           ['--serial-id=' + device_serial, '--map', str(device_port),
  94            str(host_port)] for device_port, host_port in port_pairs]
  95       logging.info('Forwarding using commands: %s', redirection_commands)
  96
  97       for redirection_command in redirection_commands:
  98         try:
  99           (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 100               [instance._host_forwarder_path] + redirection_command)
 101         except OSError as e:
 102           if e.errno == 2:
 103             raise Exception('Unable to start host forwarder. Make sure you have'
 104                             ' built host_forwarder.')
 105           else: raise
 106         if exit_code != 0:
 107           Forwarder._KillDeviceLocked(device, tool)
 108           raise Exception('%s exited with %d:\n%s' % (
 109               instance._host_forwarder_path, exit_code, '\n'.join(output)))
 110         tokens = output.split(':')
 111         if len(tokens) != 2:
 112           raise Exception('Unexpected host forwarder output "%s", '
 113                           'expected "device_port:host_port"' % output)
 114         device_port = int(tokens[0])
 115         host_port = int(tokens[1])
 116         serial_with_port = (device_serial, device_port)
 117         instance._device_to_host_port_map[serial_with_port] = host_port
 118         instance._host_to_device_port_map[host_port] = serial_with_port
 119         logging.info('Forwarding device port: %d to host port: %d.',
 120                      device_port, host_port)
 121
 122   @staticmethod
 123   def UnmapDevicePort(device_port, device):
 124     """Unmaps a previously forwarded device port.
 125
 126     Args:
 127       device: A DeviceUtils instance.
 128       device_port: A previously forwarded port (through Map()).
 129     """
 130     # TODO(jbudorick) Remove once telemetry gets switched over.
 131     if isinstance(device, pylib.android_commands.AndroidCommands):
 132       device = pylib.device.device_utils.DeviceUtils(device)
 133     with _FileLock(Forwarder._LOCK_PATH):
 134       Forwarder._UnmapDevicePortLocked(device_port, device)
 135
 136   @staticmethod
 137   def UnmapAllDevicePorts(device):
 138     """Unmaps all the previously forwarded ports for the provided device.
 139
 140     Args:
 141       device: A DeviceUtils instance.
 142       port_pairs: A list of tuples (device_port, host_port) to unmap.
 143     """
 144     # TODO(jbudorick) Remove once telemetry gets switched over.
 145     if isinstance(device, pylib.android_commands.AndroidCommands):
 146       device = pylib.device.device_utils.DeviceUtils(device)
 147     with _FileLock(Forwarder._LOCK_PATH):
 148       if not Forwarder._instance:
 149         return
 150       adb_serial = str(device)
 151       if adb_serial not in Forwarder._instance._initialized_devices:
 152         return
 153       port_map = Forwarder._GetInstanceLocked(
 154           None)._device_to_host_port_map
 155       for (device_serial, device_port) in port_map.keys():
 156         if adb_serial == device_serial:
 157           Forwarder._UnmapDevicePortLocked(device_port, device)
 158       # There are no more ports mapped, kill the device_forwarder.
 159       tool = valgrind_tools.CreateTool(None, device)
 160       Forwarder._KillDeviceLocked(device, tool)
 161
 162   @staticmethod
 163   def DevicePortForHostPort(host_port):
 164     """Returns the device port that corresponds to a given host port."""
 165     with _FileLock(Forwarder._LOCK_PATH):
 166       (_device_serial, device_port) = Forwarder._GetInstanceLocked(
 167           None)._host_to_device_port_map.get(host_port)
 168       return device_port
 169
 170   @staticmethod
 171   def RemoveHostLog():
 172     if os.path.exists(Forwarder._HOST_FORWARDER_LOG):
 173       os.unlink(Forwarder._HOST_FORWARDER_LOG)
 174
 175   @staticmethod
 176   def GetHostLog():
 177     if not os.path.exists(Forwarder._HOST_FORWARDER_LOG):
 178       return ''
 179     with file(Forwarder._HOST_FORWARDER_LOG, 'r') as f:
 180       return f.read()
 181
 182   @staticmethod
 183   def _GetInstanceLocked(tool):
 184     """Returns the singleton instance.
 185
 186     Note that the global lock must be acquired before calling this method.
 187
 188     Args:
 189       tool: Tool class to use to get wrapper, if necessary, for executing the
 190             forwarder (see valgrind_tools.py).
 191     """
 192     if not Forwarder._instance:
 193       Forwarder._instance = Forwarder(tool)
 194     return Forwarder._instance
 195
 196   def __init__(self, tool):
 197     """Constructs a new instance of Forwarder.
 198
 199     Note that Forwarder is a singleton therefore this constructor should be
 200     called only once.
 201
 202     Args:
 203       tool: Tool class to use to get wrapper, if necessary, for executing the
 204             forwarder (see valgrind_tools.py).
 205     """
 206     assert not Forwarder._instance
 207     self._tool = tool
 208     self._initialized_devices = set()
 209     self._device_to_host_port_map = dict()
 210     self._host_to_device_port_map = dict()
 211     self._host_forwarder_path = os.path.join(
 212         constants.GetOutDirectory(), 'host_forwarder')
 213     assert os.path.exists(self._host_forwarder_path), 'Please build forwarder2'
 214     self._device_forwarder_path_on_host = os.path.join(
 215         constants.GetOutDirectory(), 'forwarder_dist')
 216     self._InitHostLocked()
 217
 218   @staticmethod
 219   def _UnmapDevicePortLocked(device_port, device):
 220     """Internal method used by UnmapDevicePort().
 221
 222     Note that the global lock must be acquired before calling this method.
 223     """
 224     instance = Forwarder._GetInstanceLocked(None)
 225     serial = str(device)
 226     serial_with_port = (serial, device_port)
 227     if not serial_with_port in instance._device_to_host_port_map:
 228       logging.error('Trying to unmap non-forwarded port %d' % device_port)
 229       return
 230     redirection_command = ['--serial-id=' + serial, '--unmap', str(device_port)]
 231     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 232         [instance._host_forwarder_path] + redirection_command)
 233     if exit_code != 0:
 234       logging.error('%s exited with %d:\n%s' % (
 235           instance._host_forwarder_path, exit_code, '\n'.join(output)))
 236     host_port = instance._device_to_host_port_map[serial_with_port]
 237     del instance._device_to_host_port_map[serial_with_port]
 238     del instance._host_to_device_port_map[host_port]
 239
 240   @staticmethod
 241   def _GetPidForLock():
 242     """Returns the PID used for host_forwarder initialization.
 243
 244     In case multi-process sharding is used, the PID of the "sharder" is used.
 245     The "sharder" is the initial process that forks that is the parent process.
 246     By default, multi-processing is not used. In that case the PID of the
 247     current process is returned.
 248     """
 249     use_multiprocessing = Forwarder._MULTIPROCESSING_ENV_VAR in os.environ
 250     return os.getpgrp() if use_multiprocessing else os.getpid()
 251
 252   def _InitHostLocked(self):
 253     """Initializes the host forwarder daemon.
 254
 255     Note that the global lock must be acquired before calling this method. This
 256     method kills any existing host_forwarder process that could be stale.
 257     """
 258     # See if the host_forwarder daemon was already initialized by a concurrent
 259     # process or thread (in case multi-process sharding is not used).
 260     pid_for_lock = Forwarder._GetPidForLock()
 261     fd = os.open(Forwarder._LOCK_PATH, os.O_RDWR | os.O_CREAT)
 262     with os.fdopen(fd, 'r+') as pid_file:
 263       pid_with_start_time = pid_file.readline()
 264       if pid_with_start_time:
 265         (pid, process_start_time) = pid_with_start_time.split(':')
 266         if pid == str(pid_for_lock):
 267           if process_start_time == str(_GetProcessStartTime(pid_for_lock)):
 268             return
 269       self._KillHostLocked()
 270       pid_file.seek(0)
 271       pid_file.write(
 272           '%s:%s' % (pid_for_lock, str(_GetProcessStartTime(pid_for_lock))))
 273
 274   def _InitDeviceLocked(self, device, tool):
 275     """Initializes the device_forwarder daemon for a specific device (once).
 276
 277     Note that the global lock must be acquired before calling this method. This
 278     method kills any existing device_forwarder daemon on the device that could
 279     be stale, pushes the latest version of the daemon (to the device) and starts
 280     it.
 281
 282     Args:
 283       device: A DeviceUtils instance.
 284       tool: Tool class to use to get wrapper, if necessary, for executing the
 285             forwarder (see valgrind_tools.py).
 286     """
 287     device_serial = str(device)
 288     if device_serial in self._initialized_devices:
 289       return
 290     Forwarder._KillDeviceLocked(device, tool)
 291     device.PushChangedFiles([(
 292         self._device_forwarder_path_on_host,
 293         Forwarder._DEVICE_FORWARDER_FOLDER)])
 294     cmd = '%s %s' % (tool.GetUtilWrapper(), Forwarder._DEVICE_FORWARDER_PATH)
 295     (exit_code, output) = device.old_interface.GetAndroidToolStatusAndOutput(
 296         cmd, lib_path=Forwarder._DEVICE_FORWARDER_FOLDER)
 297     if exit_code != 0:
 298       raise Exception(
 299           'Failed to start device forwarder:\n%s' % '\n'.join(output))
 300     self._initialized_devices.add(device_serial)
 301
 302   def _KillHostLocked(self):
 303     """Kills the forwarder process running on the host.
 304
 305     Note that the global lock must be acquired before calling this method.
 306     """
 307     logging.info('Killing host_forwarder.')
 308     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 309         [self._host_forwarder_path, '--kill-server'])
 310     if exit_code != 0:
 311       (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 312           ['pkill', '-9', 'host_forwarder'])
 313       if exit_code != 0:
 314         raise Exception('%s exited with %d:\n%s' % (
 315               self._host_forwarder_path, exit_code, '\n'.join(output)))
 316
 317   @staticmethod
 318   def _KillDeviceLocked(device, tool):
 319     """Kills the forwarder process running on the device.
 320
 321     Note that the global lock must be acquired before calling this method.
 322
 323     Args:
 324       device: Instance of DeviceUtils for talking to the device.
 325       tool: Wrapper tool (e.g. valgrind) that can be used to execute the device
 326             forwarder (see valgrind_tools.py).
 327     """
 328     logging.info('Killing device_forwarder.')
 329     Forwarder._instance._initialized_devices.discard(str(device))
 330     if not device.FileExists(Forwarder._DEVICE_FORWARDER_PATH):
 331       return
 332
 333     cmd = '%s %s --kill-server' % (tool.GetUtilWrapper(),
 334                                    Forwarder._DEVICE_FORWARDER_PATH)
 335     device.old_interface.GetAndroidToolStatusAndOutput(
 336         cmd, lib_path=Forwarder._DEVICE_FORWARDER_FOLDER)