Test that debug stub works with browser.

chrome/browser/nacl_host/test/gdb_rsp.py

+# Copyright (c) 2012 The Native Client Authors. All rights reserved.

[Mark Seaborn, 2012/10/23 01:14:50]

Shouldn't have "The Native Client Authors" in the Chromium repo.

Please add a comment that this is based on gdb_rsp.py from the NaCl repo.

[halyavin, 2012/10/23 11:59:29]

Done.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import re
+import socket
+import time
+
+
+SEL_LDR_RSP_SOCKET_ADDR = ('localhost', 4014)
+
+
+def EnsurePortIsAvailable(addr=SEL_LDR_RSP_SOCKET_ADDR):

[Mark Seaborn, 2012/10/23 01:14:50]

Please remove functions you're not using, like this one.

[halyavin, 2012/10/23 11:59:29]

Done.

+  # As a sanity check, check that the TCP port is available by binding
+  # to it ourselves (and then unbinding).  Otherwise, we could end up
+  # talking to an old instance of sel_ldr that is still hanging
+  # around, or to some unrelated service that uses the same port
+  # number.  Of course, there is still a race condition because an
+  # unrelated process could bind the port after we unbind.
+  sock = socket.socket()
+  sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
+  sock.bind(addr)
+  sock.close()
+
+
+def RspChecksum(data):
+  checksum = 0
+  for char in data:
+    checksum = (checksum + ord(char)) % 0x100
+  return checksum
+
+
+class GdbRspConnection(object):
+
+  def __init__(self, addr=SEL_LDR_RSP_SOCKET_ADDR):
+    self._socket = self._Connect(addr)
+
+  def _Connect(self, addr):
+    # We have to poll because we do not know when sel_ldr has
+    # successfully done bind() on the TCP port.  This is inherently
+    # unreliable.
+    # TODO(mseaborn): Add a more reliable connection mechanism to
+    # sel_ldr's debug stub.
+    timeout_in_seconds = 10
+    poll_time_in_seconds = 0.1
+    for i in xrange(int(timeout_in_seconds / poll_time_in_seconds)):
+      # On Mac OS X, we have to create a new socket FD for each retry.
+      sock = socket.socket()
+      try:
+        sock.connect(addr)
+      except socket.error:
+        # Retry after a delay.
+        time.sleep(poll_time_in_seconds)
+      else:
+        return sock
+    raise Exception('Could not connect to sel_ldr\'s debug stub in %i seconds'
+                    % timeout_in_seconds)
+
+  def _GetReply(self):
+    reply = ''
+    while True:
+      data = self._socket.recv(1024)
+      if len(data) == 0:
+        raise AssertionError('EOF on socket reached with '
+                             'incomplete reply message: %r' % reply)
+      reply += data
+      if '#' in data:
+        break
+    print reply
+    match = re.match('\+\$([^#]*)#([0-9a-fA-F]{2})$', reply)
+    if match is None:
+      raise AssertionError('Unexpected reply message: %r' % reply)
+    reply_body = match.group(1)
+    checksum = match.group(2)
+    expected_checksum = '%02x' % RspChecksum(reply_body)
+    if checksum != expected_checksum:
+      raise AssertionError('Bad RSP checksum: %r != %r' %
+                           (checksum, expected_checksum))
+    # Send acknowledgement.
+    self._socket.send('+')
+    return reply_body
+
+  # Send an rsp message, but don't wait for or expect a reply.
+  def RspSendOnly(self, data):
+    msg = '$%s#%02x' % (data, RspChecksum(data))
+    return self._socket.send(msg)
+
+  def RspRequest(self, data):
+    self.RspSendOnly(data)
+    return self._GetReply()
+
+  def RspInterrupt(self):
+    self._socket.send('\x03')
+    return self._GetReply()