Migrate device utils WriteFile to AdbWrapper

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=W0613
 
 import logging
 import multiprocessing
 import os
 import re
 import sys
 import tempfile
 import time
 import zipfile
 
 import pylib.android_commands
 from pylib import cmd_helper
 from pylib.device import adb_wrapper
 from pylib.device import decorators
 from pylib.device import device_errors
 from pylib.device.commands import install_commands
 from pylib.utils import apk_helper
+from pylib.utils import device_temp_file
 from pylib.utils import host_utils
 from pylib.utils import parallelizer
 from pylib.utils import timeout_retry
 
 _DEFAULT_TIMEOUT = 30
 _DEFAULT_RETRIES = 3
 
 
 @decorators.WithExplicitTimeoutAndRetries(
     _DEFAULT_TIMEOUT, _DEFAULT_RETRIES)
@@ skipping 385 matching lines @@
       DeviceUnreachableError on missing device.
     """
     def env_quote(key, value):
       if not DeviceUtils._VALID_SHELL_VARIABLE.match(key):
         raise KeyError('Invalid shell variable name %r' % key)
       # using double quotes here to allow interpolation of shell variables
       return '%s=%s' % (key, cmd_helper.DoubleQuote(value))
 
     if not isinstance(cmd, basestring):
       cmd = ' '.join(cmd_helper.SingleQuote(s) for s in cmd)
-    if as_root and self.NeedsSU():
-      cmd = 'su -c %s' % cmd
     if env:
       env = ' '.join(env_quote(k, v) for k, v in env.iteritems())
       cmd = '%s %s' % (env, cmd)
     if cwd:
       cmd = 'cd %s && %s' % (cmd_helper.SingleQuote(cwd), cmd)
+    if as_root and self.NeedsSU():
+      # "su -c sh -c" allows using shell features in |cmd|

[Sami, 2014/11/12 19:45:38]

Random thought: subprocess lets you use shell=True/False to control this
behavior. It's mostly for security, which isn't the top priority here.

+      cmd = 'su -c sh -c %s' % cmd_helper.SingleQuote(cmd)

[perezju, 2014/11/12 19:30:41]

I also moved the root check to the end so that, e.g., having the options
cwd='/path/to/protected/folder' and as_root=True together work as expected.

     if timeout is None:
       timeout = self._default_timeout
 
     try:
       output = self.adb.Shell(cmd)
     except device_errors.AdbShellCommandFailedError as e:
       if check_return:
         raise
       else:
         output = e.output
@@ skipping 410 matching lines @@
     # the implementation switch, and if file not found should raise exception.
     if as_root:
       if not self.old_interface.CanAccessProtectedFileContents():
         raise device_errors.CommandFailedError(
           'Cannot read from %s with root privileges.' % device_path)
       return self.old_interface.GetProtectedFileContents(device_path)
     else:
       return self.old_interface.GetFileContents(device_path)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
-  def WriteFile(self, device_path, contents, as_root=False, timeout=None,
-                retries=None):
+  def WriteFile(self, device_path, contents, as_root=False, force_push=False,
+                timeout=None, retries=None):
     """Writes |contents| to a file on the device.
 
     Args:
       device_path: A string containing the absolute path to the file to write
-                   on the device.
+          on the device.
       contents: A string containing the data to write to the device.
       as_root: A boolean indicating whether the write should be executed with
-               root privileges.
+          root privileges (if available).
+      force_push: A boolean indicating whether to force the operation to be
+          performed by pushing a file to the device. The default is, when the
+          contents are short, to pass the contents using a shell script instead.
       timeout: timeout in seconds
       retries: number of retries
 
     Raises:
       CommandFailedError if the file could not be written on the device.
       CommandTimeoutError on timeout.
       DeviceUnreachableError on missing device.
     """
-    if as_root:
-      if not self.old_interface.CanAccessProtectedFileContents():
-        raise device_errors.CommandFailedError(
-            'Cannot write to %s with root privileges.' % device_path)
-      self.old_interface.SetProtectedFileContents(device_path, contents)
+    if len(contents) < 512 and not force_push:
+      cmd = 'echo -n %s > %s' % (cmd_helper.SingleQuote(contents),
+                                 cmd_helper.SingleQuote(device_path))
+      self.RunShellCommand(cmd, as_root=as_root, check_return=True)

[perezju, 2014/11/12 19:30:41]

Now RunShellCommand will "do the right thing", so no need for special treatment
of the command here. This will also "automagically" fix the same bug for other
clients attempting to run echo (or other shell features) through RunShellCommand
with as_root=True.

Thanks Sami for helping to spot this!

     else:
-      self.old_interface.SetFileContents(device_path, contents)
-
-  @decorators.WithTimeoutAndRetriesFromInstance()
-  def WriteTextFile(self, device_path, text, as_root=False, timeout=None,
-                    retries=None):
-    """Writes |text| to a file on the device.
-
-    Assuming that |text| is a small string, this is typically more efficient
-    than |WriteFile|, as no files are pushed into the device.
-
-    Args:
-      device_path: A string containing the absolute path to the file to write
-                   on the device.
-      text: A short string of text to write to the file on the device.
-      as_root: A boolean indicating whether the write should be executed with
-               root privileges.
-      timeout: timeout in seconds
-      retries: number of retries
-
-    Raises:
-      CommandFailedError if the file could not be written on the device.
-      CommandTimeoutError on timeout.
-      DeviceUnreachableError on missing device.
-    """
-    cmd = 'echo %s > %s' % (cmd_helper.SingleQuote(text),
-                            cmd_helper.SingleQuote(device_path))
-    self.RunShellCommand(cmd, as_root=as_root, check_return=True)
+      with tempfile.NamedTemporaryFile() as host_temp:
+        host_temp.write(contents)
+        host_temp.flush()
+        if as_root and self.NeedsSU():
+          with device_temp_file.DeviceTempFile(self) as device_temp:
+            self.adb.Push(host_temp.name, device_temp.name)
+            # Here we need 'cp' rather than 'mv' because the temp and
+            # destination files might be on different file systems (e.g.
+            # on internal storage and an external sd card)
+            self.RunShellCommand(['cp', device_temp.name, device_path],
+                                 as_root=True, check_return=True)
+        else:
+          self.adb.Push(host_temp.name, device_path)
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def Ls(self, device_path, timeout=None, retries=None):
     """Lists the contents of a directory on the device.
 
     Args:
       device_path: A string containing the path of the directory on the device
                    to list.
       timeout: timeout in seconds
       retries: number of retries
@@ skipping 220 matching lines @@
     Returns:
       A Parallelizer operating over |devices|.
     """
     if not devices or len(devices) == 0:
       devices = pylib.android_commands.GetAttachedDevices()
     parallelizer_type = (parallelizer.Parallelizer if async
                          else parallelizer.SyncParallelizer)
     return parallelizer_type([
         d if isinstance(d, DeviceUtils) else DeviceUtils(d)
         for d in devices])