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 GdbRspConnection(object):
  20
  21   def __init__(self, addr):
  22     self._socket = self._Connect(addr)
  23
  24   def _Connect(self, addr):
  25     # We have to poll because we do not know when sel_ldr has
  26     # successfully done bind() on the TCP port.  This is inherently
  27     # unreliable.
  28     # TODO(mseaborn): Add a more reliable connection mechanism to
  29     # sel_ldr's debug stub.
  30     timeout_in_seconds = 10
  31     poll_time_in_seconds = 0.1
  32     for i in xrange(int(timeout_in_seconds / poll_time_in_seconds)):
  33       # On Mac OS X, we have to create a new socket FD for each retry.
  34       sock = socket.socket()
  35       try:
  36         sock.connect(addr)
  37       except socket.error:
  38         # Retry after a delay.
  39         time.sleep(poll_time_in_seconds)
  40       else:
  41         return sock
  42     raise Exception('Could not connect to sel_ldr\'s debug stub in %i seconds'
  43                     % timeout_in_seconds)
  44
  45   def _GetReply(self):
  46     reply = ''
  47     while True:
  48       data = self._socket.recv(1024)
  49       if len(data) == 0:
  50         raise AssertionError('EOF on socket reached with '
  51                              'incomplete reply message: %r' % reply)
  52       reply += data
  53       if '#' in data:
  54         break
  55     match = re.match('\+\$([^#]*)#([0-9a-fA-F]{2})$', reply)
  56     if match is None:
  57       raise AssertionError('Unexpected reply message: %r' % reply)
  58     reply_body = match.group(1)
  59     checksum = match.group(2)
  60     expected_checksum = '%02x' % RspChecksum(reply_body)
  61     if checksum != expected_checksum:
  62       raise AssertionError('Bad RSP checksum: %r != %r' %
  63                            (checksum, expected_checksum))
  64     # Send acknowledgement.
  65     self._socket.send('+')
  66     return reply_body
  67
  68   # Send an rsp message, but don't wait for or expect a reply.
  69   def RspSendOnly(self, data):
  70     msg = '$%s#%02x' % (data, RspChecksum(data))
  71     return self._socket.send(msg)
  72
  73   def RspRequest(self, data):
  74     self.RspSendOnly(data)
  75     return self._GetReply()
  76
  77   def RspInterrupt(self):
  78     self._socket.send('\x03')
  79     return self._GetReply()