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           ['--adb=' + constants.GetAdbPath(),
  94            '--serial-id=' + device_serial,
  95            '--map', str(device_port), str(host_port)]
  96           for device_port, host_port in port_pairs]
  97       logging.info('Forwarding using commands: %s', redirection_commands)
  98
  99       for redirection_command in redirection_commands:
 100         try:
 101           (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 102               [instance._host_forwarder_path] + redirection_command)
 103         except OSError as e:
 104           if e.errno == 2:
 105             raise Exception('Unable to start host forwarder. Make sure you have'
 106                             ' built host_forwarder.')
 107           else: raise
 108         if exit_code != 0:
 109           Forwarder._KillDeviceLocked(device, tool)
 110           raise Exception('%s exited with %d:\n%s' % (
 111               instance._host_forwarder_path, exit_code, '\n'.join(output)))
 112         tokens = output.split(':')
 113         if len(tokens) != 2:
 114           raise Exception('Unexpected host forwarder output "%s", '
 115                           'expected "device_port:host_port"' % output)
 116         device_port = int(tokens[0])
 117         host_port = int(tokens[1])
 118         serial_with_port = (device_serial, device_port)
 119         instance._device_to_host_port_map[serial_with_port] = host_port
 120         instance._host_to_device_port_map[host_port] = serial_with_port
 121         logging.info('Forwarding device port: %d to host port: %d.',
 122                      device_port, host_port)
 123
 124   @staticmethod
 125   def UnmapDevicePort(device_port, device):
 126     """Unmaps a previously forwarded device port.
 127
 128     Args:
 129       device: A DeviceUtils instance.
 130       device_port: A previously forwarded port (through Map()).
 131     """
 132     # TODO(jbudorick) Remove once telemetry gets switched over.
 133     if isinstance(device, pylib.android_commands.AndroidCommands):
 134       device = pylib.device.device_utils.DeviceUtils(device)
 135     with _FileLock(Forwarder._LOCK_PATH):
 136       Forwarder._UnmapDevicePortLocked(device_port, device)
 137
 138   @staticmethod
 139   def UnmapAllDevicePorts(device):
 140     """Unmaps all the previously forwarded ports for the provided device.
 141
 142     Args:
 143       device: A DeviceUtils instance.
 144       port_pairs: A list of tuples (device_port, host_port) to unmap.
 145     """
 146     # TODO(jbudorick) Remove once telemetry gets switched over.
 147     if isinstance(device, pylib.android_commands.AndroidCommands):
 148       device = pylib.device.device_utils.DeviceUtils(device)
 149     with _FileLock(Forwarder._LOCK_PATH):
 150       if not Forwarder._instance:
 151         return
 152       adb_serial = str(device)
 153       if adb_serial not in Forwarder._instance._initialized_devices:
 154         return
 155       port_map = Forwarder._GetInstanceLocked(
 156           None)._device_to_host_port_map
 157       for (device_serial, device_port) in port_map.keys():
 158         if adb_serial == device_serial:
 159           Forwarder._UnmapDevicePortLocked(device_port, device)
 160       # There are no more ports mapped, kill the device_forwarder.
 161       tool = valgrind_tools.CreateTool(None, device)
 162       Forwarder._KillDeviceLocked(device, tool)
 163
 164   @staticmethod
 165   def DevicePortForHostPort(host_port):
 166     """Returns the device port that corresponds to a given host port."""
 167     with _FileLock(Forwarder._LOCK_PATH):
 168       (_device_serial, device_port) = Forwarder._GetInstanceLocked(
 169           None)._host_to_device_port_map.get(host_port)
 170       return device_port
 171
 172   @staticmethod
 173   def RemoveHostLog():
 174     if os.path.exists(Forwarder._HOST_FORWARDER_LOG):
 175       os.unlink(Forwarder._HOST_FORWARDER_LOG)
 176
 177   @staticmethod
 178   def GetHostLog():
 179     if not os.path.exists(Forwarder._HOST_FORWARDER_LOG):
 180       return ''
 181     with file(Forwarder._HOST_FORWARDER_LOG, 'r') as f:
 182       return f.read()
 183
 184   @staticmethod
 185   def _GetInstanceLocked(tool):
 186     """Returns the singleton instance.
 187
 188     Note that the global lock must be acquired before calling this method.
 189
 190     Args:
 191       tool: Tool class to use to get wrapper, if necessary, for executing the
 192             forwarder (see valgrind_tools.py).
 193     """
 194     if not Forwarder._instance:
 195       Forwarder._instance = Forwarder(tool)
 196     return Forwarder._instance
 197
 198   def __init__(self, tool):
 199     """Constructs a new instance of Forwarder.
 200
 201     Note that Forwarder is a singleton therefore this constructor should be
 202     called only once.
 203
 204     Args:
 205       tool: Tool class to use to get wrapper, if necessary, for executing the
 206             forwarder (see valgrind_tools.py).
 207     """
 208     assert not Forwarder._instance
 209     self._tool = tool
 210     self._initialized_devices = set()
 211     self._device_to_host_port_map = dict()
 212     self._host_to_device_port_map = dict()
 213     self._host_forwarder_path = os.path.join(
 214         constants.GetOutDirectory(), 'host_forwarder')
 215     assert os.path.exists(self._host_forwarder_path), 'Please build forwarder2'
 216     self._device_forwarder_path_on_host = os.path.join(
 217         constants.GetOutDirectory(), 'forwarder_dist')
 218     self._InitHostLocked()
 219
 220   @staticmethod
 221   def _UnmapDevicePortLocked(device_port, device):
 222     """Internal method used by UnmapDevicePort().
 223
 224     Note that the global lock must be acquired before calling this method.
 225     """
 226     instance = Forwarder._GetInstanceLocked(None)
 227     serial = str(device)
 228     serial_with_port = (serial, device_port)
 229     if not serial_with_port in instance._device_to_host_port_map:
 230       logging.error('Trying to unmap non-forwarded port %d' % device_port)
 231       return
 232     redirection_command = ['--adb=' + constants.GetAdbPath(),
 233                            '--serial-id=' + serial,
 234                            '--unmap', str(device_port)]
 235     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 236         [instance._host_forwarder_path] + redirection_command)
 237     if exit_code != 0:
 238       logging.error('%s exited with %d:\n%s' % (
 239           instance._host_forwarder_path, exit_code, '\n'.join(output)))
 240     host_port = instance._device_to_host_port_map[serial_with_port]
 241     del instance._device_to_host_port_map[serial_with_port]
 242     del instance._host_to_device_port_map[host_port]
 243
 244   @staticmethod
 245   def _GetPidForLock():
 246     """Returns the PID used for host_forwarder initialization.
 247
 248     In case multi-process sharding is used, the PID of the "sharder" is used.
 249     The "sharder" is the initial process that forks that is the parent process.
 250     By default, multi-processing is not used. In that case the PID of the
 251     current process is returned.
 252     """
 253     use_multiprocessing = Forwarder._MULTIPROCESSING_ENV_VAR in os.environ
 254     return os.getpgrp() if use_multiprocessing else os.getpid()
 255
 256   def _InitHostLocked(self):
 257     """Initializes the host forwarder daemon.
 258
 259     Note that the global lock must be acquired before calling this method. This
 260     method kills any existing host_forwarder process that could be stale.
 261     """
 262     # See if the host_forwarder daemon was already initialized by a concurrent
 263     # process or thread (in case multi-process sharding is not used).
 264     pid_for_lock = Forwarder._GetPidForLock()
 265     fd = os.open(Forwarder._LOCK_PATH, os.O_RDWR | os.O_CREAT)
 266     with os.fdopen(fd, 'r+') as pid_file:
 267       pid_with_start_time = pid_file.readline()
 268       if pid_with_start_time:
 269         (pid, process_start_time) = pid_with_start_time.split(':')
 270         if pid == str(pid_for_lock):
 271           if process_start_time == str(_GetProcessStartTime(pid_for_lock)):
 272             return
 273       self._KillHostLocked()
 274       pid_file.seek(0)
 275       pid_file.write(
 276           '%s:%s' % (pid_for_lock, str(_GetProcessStartTime(pid_for_lock))))
 277       pid_file.truncate()
 278
 279   def _InitDeviceLocked(self, device, tool):
 280     """Initializes the device_forwarder daemon for a specific device (once).
 281
 282     Note that the global lock must be acquired before calling this method. This
 283     method kills any existing device_forwarder daemon on the device that could
 284     be stale, pushes the latest version of the daemon (to the device) and starts
 285     it.
 286
 287     Args:
 288       device: A DeviceUtils instance.
 289       tool: Tool class to use to get wrapper, if necessary, for executing the
 290             forwarder (see valgrind_tools.py).
 291     """
 292     device_serial = str(device)
 293     if device_serial in self._initialized_devices:
 294       return
 295     Forwarder._KillDeviceLocked(device, tool)
 296     device.PushChangedFiles([(
 297         self._device_forwarder_path_on_host,
 298         Forwarder._DEVICE_FORWARDER_FOLDER)])
 299     cmd = '%s %s' % (tool.GetUtilWrapper(), Forwarder._DEVICE_FORWARDER_PATH)
 300     (exit_code, output) = device.old_interface.GetAndroidToolStatusAndOutput(
 301         cmd, lib_path=Forwarder._DEVICE_FORWARDER_FOLDER)
 302     if exit_code != 0:
 303       raise Exception(
 304           'Failed to start device forwarder:\n%s' % '\n'.join(output))
 305     self._initialized_devices.add(device_serial)
 306
 307   def _KillHostLocked(self):
 308     """Kills the forwarder process running on the host.
 309
 310     Note that the global lock must be acquired before calling this method.
 311     """
 312     logging.info('Killing host_forwarder.')
 313     (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 314         [self._host_forwarder_path, '--kill-server'])
 315     if exit_code != 0:
 316       (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
 317           ['pkill', '-9', 'host_forwarder'])
 318       if exit_code != 0:
 319         raise Exception('%s exited with %d:\n%s' % (
 320               self._host_forwarder_path, exit_code, '\n'.join(output)))
 321
 322   @staticmethod
 323   def _KillDeviceLocked(device, tool):
 324     """Kills the forwarder process running on the device.
 325
 326     Note that the global lock must be acquired before calling this method.
 327
 328     Args:
 329       device: Instance of DeviceUtils for talking to the device.
 330       tool: Wrapper tool (e.g. valgrind) that can be used to execute the device
 331             forwarder (see valgrind_tools.py).
 332     """
 333     logging.info('Killing device_forwarder.')
 334     Forwarder._instance._initialized_devices.discard(str(device))
 335     if not device.FileExists(Forwarder._DEVICE_FORWARDER_PATH):
 336       return
 337
 338     cmd = '%s %s --kill-server' % (tool.GetUtilWrapper(),
 339                                    Forwarder._DEVICE_FORWARDER_PATH)
 340     device.old_interface.GetAndroidToolStatusAndOutput(
 341         cmd, lib_path=Forwarder._DEVICE_FORWARDER_FOLDER)