Use mutex around getaddrinfo on windows, as it's not thread-safe.

runtime/bin/socket_win.cc

 // Copyright (c) 2013, 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 "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/builtin.h"
 #include "bin/eventhandler.h"
 #include "bin/file.h"
 #include "bin/log.h"
 #include "bin/socket.h"
 #include "bin/utils.h"
 
+#include "vm/thread.h"
+
 
 namespace dart {
 namespace bin {
 
 SocketAddress::SocketAddress(struct sockaddr* sockaddr) {
   ASSERT(INET6_ADDRSTRLEN >= INET_ADDRSTRLEN);
   RawAddr* raw = reinterpret_cast<RawAddr*>(sockaddr);
 
   // Clear the port before calling WSAAddressToString as WSAAddressToString
   // includes the port in the formatted string.
@@ skipping 185 matching lines @@
   ListenSocket* listen_socket = reinterpret_cast<ListenSocket*>(fd);
   ClientSocket* client_socket = listen_socket->Accept();
   if (client_socket != NULL) {
     return reinterpret_cast<intptr_t>(client_socket);
   } else {
     return -1;
   }
 }
 
 
+static Mutex* getaddrinfo_mutex = new Mutex();
 AddressList<SocketAddress>* Socket::LookupAddress(const char* host,
                                                   int type,
                                                   OSError** os_error) {
   Initialize();
 
+  // getaddrinfo is not thread-safe on Windows. Use a mutex to get around it.
+  MutexLocker locker(getaddrinfo_mutex);
+
   // Perform a name lookup for a host name.
   struct addrinfo hints;
   memset(&hints, 0, sizeof(hints));
   hints.ai_family = SocketAddress::FromType(type);
   hints.ai_socktype = SOCK_STREAM;
   hints.ai_flags = 0;
   hints.ai_protocol = IPPROTO_TCP;
   struct addrinfo* info = NULL;
   int status = getaddrinfo(host, 0, &hints, &info);
   if (status != 0) {
@@ skipping 400 matching lines @@
                     proto,
                     MCAST_LEAVE_GROUP,
                     reinterpret_cast<char *>(&mreq),
                     sizeof(mreq)) == 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)