chrome/test/data/nacl/gdb_rsp.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 # This file is based on gdb_rsp.py file from NaCl repository.
   6
   7 import re
   8 import socket
   9 import time
  10
  11
  12 def RspChecksum(data):
  13   checksum = 0
  14   for char in data:
  15     checksum = (checksum + ord(char)) % 0x100
  16   return checksum
  17
  18
  19 class EofOnReplyException(Exception):
  20
  21   pass
  22
  23
  24 class GdbRspConnection(object):
  25
  26   def __init__(self, addr):
  27     self._socket = self._Connect(addr)
  28
  29   def _Connect(self, addr):
  30     # We have to poll because we do not know when sel_ldr has
  31     # successfully done bind() on the TCP port.  This is inherently
  32     # unreliable.
  33     # TODO(mseaborn): Add a more reliable connection mechanism to
  34     # sel_ldr's debug stub.
  35     timeout_in_seconds = 10
  36     poll_time_in_seconds = 0.1
  37     for i in xrange(int(timeout_in_seconds / poll_time_in_seconds)):
  38       # On Mac OS X, we have to create a new socket FD for each retry.
  39       sock = socket.socket()
  40       try:
  41         sock.connect(addr)
  42       except socket.error:
  43         # Retry after a delay.
  44         time.sleep(poll_time_in_seconds)
  45       else:
  46         return sock
  47     raise Exception('Could not connect to sel_ldr\'s debug stub in %i seconds'
  48                     % timeout_in_seconds)
  49
  50   def _GetReply(self):
  51     reply = ''
  52     while True:
  53       data = self._socket.recv(1024)
  54       if len(data) == 0:
  55         if reply == '+':
  56           raise EofOnReplyException()
  57         raise AssertionError('EOF on socket reached with '
  58                              'incomplete reply message: %r' % reply)
  59       reply += data
  60       if '#' in data:
  61         break
  62     match = re.match('\+\$([^#]*)#([0-9a-fA-F]{2})$', reply)
  63     if match is None:
  64       raise AssertionError('Unexpected reply message: %r' % reply)
  65     reply_body = match.group(1)
  66     checksum = match.group(2)
  67     expected_checksum = '%02x' % RspChecksum(reply_body)
  68     if checksum != expected_checksum:
  69       raise AssertionError('Bad RSP checksum: %r != %r' %
  70                            (checksum, expected_checksum))
  71     # Send acknowledgement.
  72     self._socket.send('+')
  73     return reply_body
  74
  75   # Send an rsp message, but don't wait for or expect a reply.
  76   def RspSendOnly(self, data):
  77     msg = '$%s#%02x' % (data, RspChecksum(data))
  78     return self._socket.send(msg)
  79
  80   def RspRequest(self, data):
  81     self.RspSendOnly(data)
  82     return self._GetReply()
  83
  84   def RspInterrupt(self):
  85     self._socket.send('\x03')
  86     return self._GetReply()