Fix issue 20133: do not crash if debug port is illegal.

runtime/bin/dbg_connection.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/dbg_connection.h"
 #include "bin/dbg_message.h"
 #include "bin/dartutils.h"
 #include "bin/lockers.h"
 #include "bin/log.h"
 #include "bin/socket.h"
@@ skipping 313 matching lines @@
   // Now setup a listener socket and start a thread which will
   // listen, accept connections from debuggers, read and handle/dispatch
   // debugger commands received on these connections.
   ASSERT(listener_fd_ == -1);
   OSError *os_error;
   AddressList<SocketAddress>* addresses =
       Socket::LookupAddress(address, -1, &os_error);
   listener_fd_ = ServerSocket::CreateBindListen(
       addresses->GetAt(0)->addr(), port_number, 1);
   delete addresses;
+  if (listener_fd_ < 0) {
+    fprintf(stderr, "%s", "Could not initialize debug socket\n");
+    fflush(stderr);
+    exit(255);

[siva, 2014/10/15 22:58:41]

This file seems to use FATAL("....") whenever it gets an error, see above.

[srdjan, 2014/10/16 15:47:45]

FATAL crashes the VM, I assume it is used for the cases that cannot occur in
normal operation. Since the failure of creating a listener_fd_ can occur when
passing wrong arguments, this CL reports an error without crashing the VM.

+  }
+
   port_number = Socket::GetPort(listener_fd_);
   DebuggerConnectionImpl::StartHandler(port_number);
   return port_number;
 }
 
 
 void DebuggerConnectionHandler::WaitForConnection() {
   ASSERT(handler_lock_ != NULL);
   MonitorLocker ml(handler_lock_);
   if (!IsListening()) {
@@ skipping 156 matching lines @@
 
 
 bool DebuggerConnectionHandler::IsConnected() {
   // TODO(asiva): Support multiple debugger connections.
   // Return true if a connection has been established.
   return singleton_handler != NULL;
 }
 
 }  // namespace bin
 }  // namespace dart