[Android] Add PIE support for ICS devices.

build/android/pylib/device/device_utils.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Provides a variety of device interactions based on adb.
 
 Eventually, this will be based on adb_wrapper.
 """
 # pylint: disable=unused-argument
 
@@ skipping 394 matching lines @@
       should_install = bool(self._GetChangedFilesImpl(apk_path, device_path))
       if should_install and not reinstall:
         self.adb.Uninstall(package_name)
     else:
       should_install = True
     if should_install:
       self.adb.Install(apk_path, reinstall=reinstall)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def RunShellCommand(self, cmd, check_return=False, cwd=None, env=None,
-                      as_root=False, single_line=False,
-                      timeout=None, retries=None):
+                      as_root=False, single_line=False, timeout=None,
+                      retries=None):
     """Run an ADB shell command.
 
     The command to run |cmd| should be a sequence of program arguments or else
     a single string.
 
     When |cmd| is a sequence, it is assumed to contain the name of the command
     to run followed by its arguments. In this case, arguments are passed to the
     command exactly as given, without any further processing by the shell. This
     allows to easily pass arguments containing spaces or special characters
     without having to worry about getting quoting right. Whenever possible, it
@@ skipping 898 matching lines @@
     Args:
       timeout: timeout in seconds
       retries: number of retries
     """
     return logcat_monitor.LogcatMonitor(self.adb, *args, **kwargs)
 
   def __str__(self):
     """Returns the device serial."""
     return self.adb.GetDeviceSerial()
 
+  @decorators.WithTimeoutAndRetriesFromInstance()
+  def GetDevicePieWrapper(self, timeout=None, retries=None):
+    """Gets the absolute path to the run_pie wrapper on the device.
+
+    We have to build our device executables to be PIE, but they need to be able
+    to run on versions of android that don't support PIE (i.e. ICS and below).
+    To do so, we push a wrapper to the device that lets older android versions
+    run PIE executables. This method pushes that wrapper to the device if
+    necessary and returns the path to it.
+
+    This is exposed publicly to allow clients to write scripts using run_pie
+    (e.g. md5sum.CalculateDeviceMd5Sum).
+
+    Args:
+      timeout: timeout in seconds
+      retries: number of retries
+
+    Returns:
+      The path to the PIE wrapper on the device, or an empty string if the
+      device does not require the wrapper.
+    """
+    if 'run_pie' not in self._cache:
+      pie = ''
+      if (self.build_version_sdk <
+          constants.ANDROID_SDK_VERSION_CODES.JELLY_BEAN):
+        host_pie_path = os.path.join(constants.GetOutDirectory(), 'run_pie')
+        if not os.path.exists(host_pie_path):
+          raise device_errors.CommandFailedError('Please build run_pie')
+        pie = '%s/run_pie' % constants.TEST_EXECUTABLE_DIR
+        self.adb.Push(host_pie_path, pie)
+
+      self._cache['run_pie'] = pie
+
+    return self._cache['run_pie']
+
   @classmethod
   def parallel(cls, devices=None, async=False):
     """Creates a Parallelizer to operate over the provided list of devices.
 
     If |devices| is either |None| or an empty list, the Parallelizer will
     operate over all attached devices.
 
     Args:
       devices: A list of either DeviceUtils instances or objects from
                from which DeviceUtils instances can be constructed. If None,
                all attached devices will be used.
       async: If true, returns a Parallelizer that runs operations
              asynchronously.
 
     Returns:
       A Parallelizer operating over |devices|.
     """
     if not devices:
       devices = adb_wrapper.AdbWrapper.GetDevices()
     devices = [d if isinstance(d, cls) else cls(d) for d in devices]
     if async:
       return parallelizer.Parallelizer(devices)
     else:
       return parallelizer.SyncParallelizer(devices)