Android Telemetry: automates devices running "user" build.

build/android/pylib/android_commands.py

 # Copyright (c) 2012 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 an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 
 import collections
@@ skipping 676 matching lines @@
     # NOTE: We can't use adb_interface.Push() because it hardcodes a timeout of
     # 60 seconds which isn't sufficient for a lot of users of this method.
     push_command = 'push %s %s' % (local_path, device_path)
     logging.info('>>> $' + push_command)
     output = self._adb.SendCommand(push_command, timeout_time=30 * 60)
     assert _HasAdbPushSucceeded(output)
 
 
   def GetFileContents(self, filename, log_result=False):
     """Gets contents from the file specified by |filename|."""
-    return self.RunShellCommand('if [ -f "' + filename + '" ]; then cat "' +
-                                filename + '"; fi', log_result=log_result)
+    return self.RunShellCommand('cat "%s" 2>/dev/null' % filename,
+                                log_result=log_result)
 
   def SetFileContents(self, filename, contents):
     """Writes |contents| to the file specified by |filename|."""
     with tempfile.NamedTemporaryFile() as f:
       f.write(contents)
       f.flush()
       self._adb.Push(f.name, filename)
 
   _TEMP_FILE_BASE_FMT = 'temp_file_%d'
   _TEMP_SCRIPT_FILE_BASE_FMT = 'temp_script_file_%d.sh'
 
   def _GetDeviceTempFileName(self, base_name):
     i = 0
     while self.FileExistsOnDevice(
         self.GetExternalStorage() + '/' + base_name % i):
       i += 1
     return self.GetExternalStorage() + '/' + base_name % i
 
+  def CanAccessProtectedFileContents(self):
+    """Returns True if Get/SetProtectedFileContents would work via "su".
+
+    Devices running user builds don't have adb root, but may provide "su" which
+    can be used for accessing protected files.
+    """
+    return self.RunShellCommand('su -c echo') == ['']
+
+  def GetProtectedFileContents(self, filename, log_result=False):
+    """Gets contents from the protected file specified by |filename|.
+
+    This is less efficient than GetFileContents, but will work for protected
+    files and device files.
+    """
+    # Run the script as root
+    return self.RunShellCommand('su -c cat "%s" 2> /dev/null' % filename)
+
   def SetProtectedFileContents(self, filename, contents):
     """Writes |contents| to the protected file specified by |filename|.
 
     This is less efficient than SetFileContents, but will work for protected
     files and device files.
     """
     temp_file = self._GetDeviceTempFileName(AndroidCommands._TEMP_FILE_BASE_FMT)
     temp_script = self._GetDeviceTempFileName(
         AndroidCommands._TEMP_SCRIPT_FILE_BASE_FMT)
 
@@ skipping 463 matching lines @@
   """
   def __init__(self, output):
     self._output = output
 
   def write(self, data):
     data = data.replace('\r\r\n', '\n')
     self._output.write(data)
 
   def flush(self):
     self._output.flush()