Check for errors of cryptohome-path.

tools/telemetry/telemetry/core/backends/chrome/cros_interface.py

 # Copyright 2013 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.
 """A wrapper around ssh for common operations on a CrOS-based device"""
 import logging
 import os
 import re
 import shutil
 import subprocess
 import sys
@@ skipping 178 matching lines @@
 
     stdout, stderr = self.RunCmdOnDevice([
         'if', 'test', '-e', file_name, ';',
         'then', 'echo', '1', ';',
         'fi'
         ], quiet=True)
     if stderr != '':
       if "Connection timed out" in stderr:
         raise OSError('Machine wasn\'t responding to ssh: %s' %
                       stderr)
-      raise OSError('Unepected error: %s' % stderr)
+      raise OSError('Unexpected error: %s' % stderr)
     exists = stdout == '1\n'
     logging.debug("FileExistsOnDevice(<text>, %s)->%s" % (file_name, exists))
     return exists
 
   def PushFile(self, filename, remote_filename):
     if self.local:
       args = ['cp', '-r', filename, remote_filename]
       stdout, stderr = GetAllCmdOutput(args, quiet=True)
       if stderr != '':
         raise OSError('No such file or directory %s' % stderr)
@@ skipping 184 matching lines @@
     df_ary = df_out.split('\n')
     # 3 lines for title, mount info, and empty line.
     if len(df_ary) == 3:
       line_ary = df_ary[1].split()
       if line_ary:
         return line_ary[0]
     return None
 
   def CryptohomePath(self, user):
     """Returns the cryptohome mount point for |user|."""
-    return self.RunCmdOnDevice(
-        ['cryptohome-path', 'user', "'%s'" % user])[0].strip()
+    stdout, stderr = self.RunCmdOnDevice(
+        ['cryptohome-path', 'user', "'%s'" % user])
+    if stderr != '':
+      raise OSError('cryptohome-path failed: %s' % stderr)
+    return stdout.rstrip()
 
   def IsCryptohomeMounted(self, username, is_guest):
     """Returns True iff |user|'s cryptohome is mounted."""
     profile_path = self.CryptohomePath(username)
     mount = self.FilesystemMountedAt(profile_path)
     mount_prefix = 'guestfs' if is_guest else '/home/.shadow/'
     return mount and mount.startswith(mount_prefix)
 
   def TakeScreenShot(self, screenshot_prefix):
     """Takes a screenshot, useful for debugging failures."""
@@ skipping 20 matching lines @@
     logging.info('(Re)starting the ui (logs the user out)')
     if clear_enterprise_policy:
       self.RunCmdOnDevice(['stop', 'ui'])
       self.RmRF('/var/lib/whitelist/*')
       self.RmRF('/home/chronos/Local\ State')
 
     if self.IsServiceRunning('ui'):
       self.RunCmdOnDevice(['restart', 'ui'])
     else:
       self.RunCmdOnDevice(['start', 'ui'])