Crash dump test: Isolate the test from any global instance of crash_service.exe

tests/inbrowser_crash_test/crash_dump_tester.py

 #!/usr/bin/python
 # Copyright (c) 2011 The Native Client 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 os
+import shutil
 import subprocess
 import sys
+import tempfile
 import time
 
 script_dir = os.path.dirname(__file__)
 sys.path.append(os.path.join(script_dir, '../../tools/browser_tester'))
 
 import browser_tester
 
 # This script extends browser_tester to check for the presence of
 # Breakpad crash dumps.
 
 
-# TODO(mseaborn): Change Chromium's crash_service.exe so that we can
-# tell it to put dumps in a per-test temp directory.
-def GetDumpDirs():
-  if sys.platform == 'win32':
-    # We duplicate Chromium's logic for deciding where its per-user
-    # directory should be on Windows.  We can remove this if we use a
-    # temp directory instead.
-    import win32com.shell.shell
-    import win32com.shell.shellcon
-    # This typically returns a pathname like
-    # 'C:\Documents and Settings\Username\Local Settings\Application Data'.
-    appdata_dir = win32com.shell.shell.SHGetFolderPath(
-        0, win32com.shell.shellcon.CSIDL_LOCAL_APPDATA, 0, 0)
-    return [os.path.join(appdata_dir, app_name, 'User Data', 'Crash Reports')
-            for app_name in ('Chromium', os.path.join('Google', 'Chrome'))]
-  else:
-    # TODO(mseaborn): Handle other platforms when NaCl supports
-    # Breakpad crash reporting there.
-    return []
-
-
-def GetDumpFiles():
-  file_list = []
-  for dump_dir in GetDumpDirs():
-    if os.path.exists(dump_dir):
-      for dump_file in sorted(os.listdir(dump_dir)):
-        file_list.append(os.path.join(dump_dir, dump_file))
-  return file_list
-
-
-def PrintDumps(desc, dump_files):
-  sys.stdout.write('crash_dump_tester: Found %i %s\n' % (len(dump_files), desc))
-  for dump_file in dump_files:
-    sys.stdout.write('  %s\n' % dump_file)
-
-
 # This reads a file of lines containing 'key:value' pairs.
 # The file contains entries like the following:
 #   plat:Win32
 #   prod:Chromium
 #   ptype:nacl-loader
 #   rept:crash svc
 def ReadDumpTxtFile(filename):
   dump_info = {}
   fh = open(filename, 'r')
   for line in fh:
     if ':' in line:
       key, value = line.rstrip().split(':', 1)
       dump_info[key] = value
   fh.close()
   return dump_info
 
 
-def StartCrashService(browser_path):
+def StartCrashService(browser_path, dumps_dir, windows_pipe_name):
   if sys.platform == 'win32':
     # Find crash_service.exe relative to chrome.exe.  This is a bit icky.
     browser_dir = os.path.dirname(browser_path)
-    proc = subprocess.Popen([os.path.join(browser_dir, 'crash_service.exe')])
+    proc = subprocess.Popen([os.path.join(browser_dir, 'crash_service.exe'),
+                             '--dumps-dir=%s' % dumps_dir,
+                             '--pipe-name=%s' % windows_pipe_name])
     def Cleanup():
-      try:
-        proc.terminate()
-        sys.stdout.write('crash_dump_tester: Stopped crash_service.exe\n')
-      except WindowsError:
-        # If the process has already exited, we will get an 'Access is
-        # denied' error.  This can happen if another instance of
-        # crash_service.exe was already running, because our instance
-        # will fail to claim the named pipe.
-        # TODO(mseaborn): We could change crash_service.exe to create
-        # unique pipe names for testing purposes.
-        pass
+      # Note that if the process has already exited, this will raise
+      # an 'Access is denied' WindowsError exception.

[Nick Bray, 2011/08/12 21:46:27]

... which should not happen in normal operation?

+      proc.terminate()
       status = proc.wait()
       sys.stdout.write('crash_dump_tester: '
                        'crash_service.exe exited with status %s\n' % status)
     # We add a delay because there is probably a race condition:
     # crash_service.exe might not have finished doing
     # CreateNamedPipe() before NaCl does a crash dump and tries to
     # connect to that pipe.
     # TODO(mseaborn): We could change crash_service.exe to report when
     # it has successfully created the named pipe.
     time.sleep(1)
   else:
     def Cleanup():
       pass
   return Cleanup
 
 
 def Main():
   parser = browser_tester.BuildArgParser()
   parser.add_option('--expected_crash_dumps', dest='expected_crash_dumps',
                     type=int, default=0,
                     help='The number of crash dumps that we should expect')
   options, args = parser.parse_args()
 
+  dumps_dir = tempfile.mkdtemp(prefix='nacl_crash_dump_tester_')
+  # To get a guaranteed unique pipe name, use the base name of the
+  # directory we just created.
+  windows_pipe_name = r'\\.\pipe\%s_crash_service' % os.path.basename(dumps_dir)
+
   # This environment variable enables Breakpad crash dumping in
   # non-official Windows builds of Chromium.
   os.environ['CHROME_HEADLESS'] = '1'
+  # Override the default (global) Windows pipe name that Chromium will
+  # use for out-of-process crash reporting.
+  os.environ['CHROME_BREAKPAD_PIPE_NAME'] = windows_pipe_name

[Nick Bray, 2011/08/12 21:46:27]

Hmmm.  Everything else being equal, I'd rather see these environment variables
passed to BrowserLauncher rather than modifying os.environ.  This isn't a small
change, so I won't require it.

 
-  dumps_before = GetDumpFiles()
-  PrintDumps('crash dump files before the test', dumps_before)
-
-  cleanup_func = StartCrashService(options.browser_path)
+  cleanup_func = StartCrashService(options.browser_path, dumps_dir,
+                                   windows_pipe_name)
   try:
     result = browser_tester.Run(options.url, options)
   finally:
     cleanup_func()
 
-  dumps_after = GetDumpFiles()
-  PrintDumps('crash dump files after the test', dumps_after)
-  # Find the new files.  This is only necessary because we are not
-  # using a clean temp directory.  This is subject to a race condition
-  # if running crash dump tests concurrently.
-  dumps_diff = sorted(set(dumps_after).difference(dumps_before))
-  PrintDumps('new crash dump files', dumps_diff)
-  new_dumps = [dump_file for dump_file in dumps_diff
+  all_files = [os.path.join(dumps_dir, dump_file)

[Nick Bray, 2011/08/12 21:46:27]

Finding the dump files should be a function taking dumps_dir.

+               for dump_file in os.listdir(dumps_dir)]
+  sys.stdout.write('crash_dump_tester: Found %i files\n' % len(all_files))
+  for dump_file in all_files:
+    sys.stdout.write('  %s\n' % dump_file)
+  dmp_files = [dump_file for dump_file in all_files
                if dump_file.endswith('.dmp')]
 
   failed = False
   msg = ('crash_dump_tester: ERROR: Got %i crash dumps but expected %i\n' %
-         (len(new_dumps), options.expected_crash_dumps))
-  if len(new_dumps) != options.expected_crash_dumps:
+         (len(dmp_files), options.expected_crash_dumps))
+  if len(dmp_files) != options.expected_crash_dumps:
     sys.stdout.write(msg)
     failed = True
-  for dump_file in new_dumps:
+  for dump_file in dmp_files:
     # The crash dumps should come in pairs of a .dmp and .txt file.
     second_file = dump_file[:-4] + '.txt'
     msg = ('crash_dump_tester: ERROR: File %r is missing a corresponding '
            '%r file\n' % (dump_file, second_file))
     if not os.path.exists(second_file):
       sys.stdout.write(msg)
       failed = True
       continue
     # Check that the crash dump comes from the NaCl process.
     dump_info = ReadDumpTxtFile(second_file)
     if 'ptype' in dump_info:
       msg = ('crash_dump_tester: ERROR: Unexpected ptype value: %r\n'
              % dump_info['ptype'])
       if dump_info['ptype'] != 'nacl-loader':
         sys.stdout.write(msg)
         failed = True
     else:
       sys.stdout.write('crash_dump_tester: ERROR: Missing ptype field\n')
       failed = True
     # TODO(mseaborn): Ideally we would also check that a backtrace
     # containing an expected function name can be extracted from the
     # crash dump.
 
   if failed:
     sys.stdout.write('crash_dump_tester: FAILED\n')
     result = 1
   else:
     sys.stdout.write('crash_dump_tester: PASSED\n')
-    # Clean up the dump files only if we are sure we produced them.
-    for dump_file in dumps_diff:
-      try:
-        os.unlink(dump_file)
-      except Exception:
-        # Handle exception in case the file is locked.
-        sys.stdout.write('crash_dump_tester: Deleting %r failed, '
-                         'but continuing anyway\n' % dump_file)
 
+  shutil.rmtree(dumps_dir)

[Nick Bray, 2011/08/12 21:46:27]

This may occasionally blow up on Windows. You should share the directory removal
code with browserlauncher.py.

   return result
 
 
 if __name__ == '__main__':
   sys.exit(Main())