Added deobfuscation script for ProGuarded stacktraces

build/android/java_deobfuscate.py

Index: build/android/java_deobfuscate.py
diff --git a/build/android/java_deobfuscate.py b/build/android/java_deobfuscate.py
new file mode 100644
index 0000000000000000000000000000000000000000..150b87c902b078d6d3e0157d3b03e3986fa78261
--- /dev/null
+++ b/build/android/java_deobfuscate.py
@@ -0,0 +1,95 @@
+# Copyright 2016 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 tool to deobfuscate java stack traces

[agrieve, 2016/07/08 14:40:13]

nit: change this to pydoc:

"""A tool to deobfuscate Java stack traces.

... description from ArgumentParser ...
"""

[smaier, 2016/07/08 16:00:31]

Done.

+
+# Can just run:
+# java -jar third_party/proguard/lib/retrace.jar -regex \
+# "(?:.*?\bat\s+%c\.%m\s*\(%s(?::%l)?\)\s*)|(?:(?:.*?[:\"]\s+)?%c(?::.*)?)" \
+# ~/mapping
+# in terminal to achieve same effect as this tool.
+
+import argparse
+import fcntl
+import os
+import select
+import subprocess
+import time
+
+# This regex is taken from
+# http://proguard.sourceforge.net/manual/retrace/usage.html.
+LINE_PARSE_REGEX = (

[agrieve, 2016/07/08 14:40:13]

nit: prefix with _

[smaier, 2016/07/08 16:00:30]

Done.

+    r'(?:.*?\bat\s+%c\.%m\s*\(%s(?::%l)?\)\s*)|(?:(?:.*?[:"]\s+)?%c(?::.*)?)')
+

[agrieve, 2016/07/08 14:40:14]

nit: here and below - 2 blank lines between top-level functions.

[smaier, 2016/07/08 16:00:31]

Done.

+def _IterProcessStdout(process, timeout=None, buffer_size=4096,

[agrieve, 2016/07/08 14:40:14]

Probably it'd be nicer to depend on the version in catapult rather than copy &
paste.

You can sneakily do this via:
import pylib  # Allows devil to be imported
from devil.utils import cmd_helper

[smaier, 2016/07/08 16:00:30]

Done.

+                       poll_interval=1):
+  try:
+    # Enable non-blocking reads from the child's stdout.
+    child_fd = process.stdout.fileno()
+    fl = fcntl.fcntl(child_fd, fcntl.F_GETFL)
+    fcntl.fcntl(child_fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+
+    end_time = (time.time() + timeout) if timeout else None
+    while True:
+      if end_time and time.time() > end_time:
+        break
+      read_fds, _, _ = select.select([child_fd], [], [], poll_interval)
+      if child_fd in read_fds:
+        data = os.read(child_fd, buffer_size)
+        if not data:
+          break
+        yield data
+      if process.poll() is not None:
+        break
+  finally:
+    try:
+      # Make sure the process doesn't stick around if we fail with an
+      # exception.
+      process.kill()
+    except OSError:
+      pass
+    process.wait()
+
+def _IterCmdOutputLines(args):
+  process = subprocess.Popen(
+      args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+  buffer_output = ''
+  for data in _IterProcessStdout(process):
+    buffer_output += data
+    has_incomplete_line = buffer_output[-1] not in '\r\n'
+    lines = buffer_output.splitlines()
+    buffer_output = lines.pop() if has_incomplete_line else ''
+    for line in lines:
+      yield line
+  if buffer_output:
+    yield buffer_output
+
+def main():
+  parser = argparse.ArgumentParser(
+      description=('Utility wrapper around ReTrace to deobfuscate stack traces '

[agrieve, 2016/07/08 14:40:13]

move this to file's docstring and use: description=__doc__

[smaier, 2016/07/08 16:00:30]

Done.

+                   'that have been mangled by ProGuard. Takes stack traces '
+                   'from stdin (eg. adb logcat | '
+                   'java_deobfuscate.py proguard.mapping) and files.'))
+  parser.add_argument(
+      'mapping_file',
+      help='ProGuard mapping file from build which the stacktrace is from.')
+  parser.add_argument(
+      '--stacktrace',
+      help='Stacktrace file to be deobfuscated.')
+  args = parser.parse_args()
+
+  retrace_path = os.path.abspath(os.path.join(
+      os.path.abspath(__file__), os.pardir, os.pardir, os.pardir, 'third_party',
+      'proguard', 'lib', 'retrace.jar'))
+
+  base_args = ['java', '-jar', retrace_path, '-regex', LINE_PARSE_REGEX,
+               args.mapping_file]
+  if args.stacktrace is not None:

[agrieve, 2016/07/08 14:40:13]

nit: drop the "is not None" part

[smaier, 2016/07/08 16:00:31]

Done.

+    subprocess.call(base_args + [args.stacktrace])
+  else:
+    for line in _IterCmdOutputLines(base_args):
+      print line
+
+if __name__ == '__main__':
+  main()