Never try to use root to run the mojo tools.

mojo/devtools/common/devtoolslib/android_shell.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.
 
 import atexit
 import hashlib
 import logging
 import os
 import os.path
 import random
@@ skipping 12 matching lines @@
 
 # Tags used by mojo shell Java logging.
 _LOGCAT_JAVA_TAGS = [
     'AndroidHandler',
     'MojoFileHelper',
     'MojoMain',
     'MojoShellActivity',
     'MojoShellApplication',
 ]
 
-# Tags used by native logging reflected in the logcat.
-_LOGCAT_NATIVE_TAGS = [
-    'chromium',
-    'sky',
-]
-
 _MOJO_SHELL_PACKAGE_NAME = 'org.chromium.mojo.shell'
 
 # Used to parse the output of `adb devices`.
 _ADB_DEVICES_HEADER = 'List of devices attached'
 
 
 _logger = logging.getLogger()
 
 
 def _exit_if_needed(process):
@@ skipping 44 matching lines @@
     adb_path: Path to adb, optional if adb is in PATH.
     target_device: Device to run on, if multiple devices are connected.
     logcat_tags: Comma-separated list of additional logcat tags to use.
   """
 
   def __init__(self, adb_path="adb", target_device=None, logcat_tags=None,
                verbose=False):
     self.adb_path = adb_path
     self.target_device = target_device
     self.stop_shell_registered = False
-    self.adb_running_as_root = None
     self.additional_logcat_tags = logcat_tags
     self.verbose_stdout = sys.stdout if verbose else open(os.devnull, 'w')
     self.verbose_stderr = sys.stderr if verbose else self.verbose_stdout
 
   def _adb_command(self, args):
     """Forms an adb command from the given arguments, prepending the adb path
     and adding a target device specifier, if needed.
     """
     adb_command = [self.adb_path]
     if self.target_device:
       adb_command.extend(['-s', self.target_device])
     adb_command.extend(args)
     return adb_command
 
   def _read_fifo(self, fifo_path, pipe, on_fifo_closed, max_attempts=5):
     """Reads |fifo_path| on the device and write the contents to |pipe|.
 
     Calls |on_fifo_closed| when the fifo is closed. This method will try to find
     the path up to |max_attempts|, waiting 1 second between each attempt. If it
     cannot find |fifo_path|, a exception will be raised.
     """
     fifo_command = self._adb_command(
-        ['shell', 'test -e "%s"; echo $?' % fifo_path])
+        ['shell', 'run-as', _MOJO_SHELL_PACKAGE_NAME, 'ls', fifo_path])
 
     def _run():
       def _wait_for_fifo():
         for _ in xrange(max_attempts):
-          if subprocess.check_output(fifo_command)[0] == '0':
+          output = subprocess.check_output(fifo_command).strip()
+          if output == fifo_path:
             return
           time.sleep(1)
         if on_fifo_closed:
           on_fifo_closed()
         raise Exception("Unable to find fifo.")
       _wait_for_fifo()
       stdout_cat = subprocess.Popen(
-          self._adb_command(['shell', 'cat', fifo_path]), stdout=pipe)
+          self._adb_command(['shell', 'run-as', _MOJO_SHELL_PACKAGE_NAME,
+                             'cat', fifo_path]), stdout=pipe)
       atexit.register(_exit_if_needed, stdout_cat)
       stdout_cat.wait()
       if on_fifo_closed:
         on_fifo_closed()
 
     thread = threading.Thread(target=_run, name="StdoutRedirector")
     thread.start()
 
   def _find_available_device_port(self):
     netstat_output = subprocess.check_output(
         self._adb_command(['shell', 'netstat']))
     return _find_available_port(netstat_output)
 
   def _forward_device_port_to_host(self, device_port, host_port):
     """Maps the device port to the host port. If |device_port| is 0, a random
     available port is chosen.
 
     Returns:
       The device port.
     """
     assert host_port
-    # Root is not required for `adb forward` (hence we don't check the return
-    # value), but if we can run adb as root, we have to do it now, because
-    # restarting adbd as root clears any port mappings. See
-    # https://github.com/domokit/devtools/issues/20.
-    self._run_adb_as_root()
 
     if device_port == 0:
       # TODO(ppi): Should we have a retry loop to handle the unlikely races?
       device_port = self._find_available_device_port()
     subprocess.check_call(self._adb_command([
         "reverse", "tcp:%d" % device_port, "tcp:%d" % host_port]))
 
     def _unmap_port():
       unmap_command = self._adb_command([
           "reverse", "--remove", "tcp:%d" % device_port])
       subprocess.Popen(unmap_command)
     atexit.register(_unmap_port)
     return device_port
 
   def _forward_host_port_to_device(self, host_port, device_port):
     """Maps the host port to the device port. If |host_port| is 0, a random
     available port is chosen.
 
     Returns:
       The host port.
     """
     assert device_port
-    self._run_adb_as_root()
 
     if host_port == 0:
       # TODO(ppi): Should we have a retry loop to handle the unlikely races?
       host_port = _find_available_host_port()
     subprocess.check_call(self._adb_command([
         "forward", 'tcp:%d' % host_port, 'tcp:%d' % device_port]))
 
     def _unmap_port():
       unmap_command = self._adb_command([
           "forward", "--remove", "tcp:%d" % device_port])
       subprocess.Popen(unmap_command)
     atexit.register(_unmap_port)
     return host_port
 
-  def _run_adb_as_root(self):
-    if self.adb_running_as_root is not None:
-      return self.adb_running_as_root
-
-    if ('cannot run as root' not in subprocess.check_output(
-        self._adb_command(['root']))):
-      # Wait for adbd to restart.
-      subprocess.check_call(
-          self._adb_command(['wait-for-device']),
-          stdout=self.verbose_stdout, stderr=self.verbose_stderr)
-      self.adb_running_as_root = True
-    else:
-      self.adb_running_as_root = False
-
-    return self.adb_running_as_root
-
   def _is_shell_package_installed(self):
     # Adb should print one line if the package is installed and return empty
     # string otherwise.
     return len(subprocess.check_output(self._adb_command([
         'shell', 'pm', 'list', 'packages', _MOJO_SHELL_PACKAGE_NAME]))) > 0
 
   @staticmethod
   def get_tmp_dir_path():
     """Returns a path to a cache directory owned by the shell where temporary
     files can be stored.
     """
     return '/data/data/%s/cache/tmp/' % _MOJO_SHELL_PACKAGE_NAME
 
   def pull_file(self, device_path, destination_path, remove_original=False):
     """Copies or moves the specified file on the device to the host."""
     subprocess.check_call(self._adb_command([
         'pull', device_path, destination_path]))
     if remove_original:
       subprocess.check_call(self._adb_command([
           'shell', 'rm', device_path]))
 
-  def check_device(self, require_root=False):
+  def check_device(self):
     """Verifies if the device configuration allows adb to run.
 
     If a target device was indicated in the constructor, it checks that the
     device is available. Otherwise, it checks that there is exactly one
     available device.
 
     Returns:
       A tuple of (result, msg). |result| is True iff if the device is correctly
       configured and False otherwise. |msg| is the reason for failure if
       |result| is False and None otherwise.
@@ skipping 13 matching lines @@
         return False, ('Cannot connect to the selected device, status: ' +
                        devices[self.target_device])
 
     if len(devices) > 1:
       return False, ('More than one device connected and target device not '
                      'specified.')
 
     if not devices.itervalues().next() == 'device':
       return False, 'Connected device is not available.'
 
-    if require_root and not self._run_adb_as_root():
-      return False, 'Cannot run on an unrooted device.'
-
     return True, None
 
   def install_apk(self, shell_apk_path):
     """Installs the apk on the device.
 
     This method computes checksum of the APK and skips the installation if the
     fingerprint matches the one saved on the device upon the previous
     installation.
 
     Args:
@@ skipping 43 matching lines @@
     STDOUT_PIPE = "/data/data/%s/stdout.fifo" % _MOJO_SHELL_PACKAGE_NAME
 
     cmd = self._adb_command(['shell', 'am', 'start',
                             '-S',
                             '-a', 'android.intent.action.VIEW',
                             '-n', '%s/.MojoShellActivity' %
                             _MOJO_SHELL_PACKAGE_NAME])
 
     parameters = []
     if stdout or on_application_stop:
-      # We need to run as root to access the fifo file we use for stdout
-      # redirection.
-      if self._run_adb_as_root():
-        # Remove any leftover fifo file after the previous run.
-        subprocess.check_call(self._adb_command(
-            ['shell', 'rm', '-f', STDOUT_PIPE]))
+      # Remove any leftover fifo file after the previous run.
+      subprocess.check_call(self._adb_command(
+          ['shell', 'run-as', _MOJO_SHELL_PACKAGE_NAME,
+           'rm', '-f', STDOUT_PIPE]))
 
-        parameters.append('--fifo-path=%s' % STDOUT_PIPE)
-        self._read_fifo(STDOUT_PIPE, stdout, on_application_stop)
-      else:
-        _logger.warning("Running without root access, full stdout of the "
-                        "shell won't be available.")
+      parameters.append('--fifo-path=%s' % STDOUT_PIPE)
+      self._read_fifo(STDOUT_PIPE, stdout, on_application_stop)
     parameters.extend(arguments)
 
     if parameters:
       device_filename = (
           '/sdcard/%s/args_%s' % (_MOJO_SHELL_PACKAGE_NAME, str(uuid.uuid4())))
       with tempfile.NamedTemporaryFile(delete=False) as temp:
         try:
           for parameter in parameters:
             temp.write(parameter)
             temp.write('\n')
@@ skipping 13 matching lines @@
     """Stops the mojo shell."""
     subprocess.check_call(self._adb_command(['shell',
                                             'am',
                                             'force-stop',
                                             _MOJO_SHELL_PACKAGE_NAME]))
 
   def clean_logs(self):
     """Cleans the logs on the device."""
     subprocess.check_call(self._adb_command(['logcat', '-c']))
 
-  def show_logs(self, include_native_logs=True):
+  def show_logs(self):
     """Displays the log for the mojo shell.
 
     Returns:
       The process responsible for reading the logs.
     """
     tags = _LOGCAT_JAVA_TAGS
-    if include_native_logs:
-      tags.extend(_LOGCAT_NATIVE_TAGS)
     if self.additional_logcat_tags is not None:
       tags.extend(self.additional_logcat_tags.split(","))
     logcat = subprocess.Popen(
         self._adb_command(['logcat', '-s', ' '.join(tags)]),
         stdout=sys.stdout)
     atexit.register(_exit_if_needed, logcat)
     return logcat
 
   def forward_observatory_ports(self):
     """Forwards the ports used by the dart observatories to the host machine.
@@ skipping 34 matching lines @@
 
   @overrides(Shell)
   def forward_host_port_to_shell(self, host_port):
     self._forward_host_port_to_device(host_port, host_port)
 
   @overrides(Shell)
   def run(self, arguments):
     self.clean_logs()
     self.forward_observatory_ports()
 
-    # If we are running as root, don't carry over the native logs from logcat -
-    # we will have these in the stdout.
-    p = self.show_logs(include_native_logs=(not self._run_adb_as_root()))
+    p = self.show_logs();
     self.start_shell(arguments, sys.stdout, p.terminate)
     p.wait()
     return None
 
   @overrides(Shell)
   def run_and_get_output(self, arguments, timeout=None):
     class Results:
       """Workaround for Python scoping rules that prevent assigning to variables
       from the outer scope.
       """
       output = None
 
     def do_run():
       (r, w) = os.pipe()
       with os.fdopen(r, "r") as rf:
         with os.fdopen(w, "w") as wf:
           self.start_shell(arguments, wf, wf.close)
           Results.output = rf.read()
 
     run_thread = threading.Thread(target=do_run)
     run_thread.start()
     run_thread.join(timeout)
 
     if run_thread.is_alive():
       self.stop_shell()
       return None, Results.output, True
     return None, Results.output, False