Fix dns on windows

lib/dns.js

@@ -33,7 +33,13 @@ function updateTimer() {
 
 
 var channel = new dns.Channel({SOCK_STATE_CB: function(socket, read, write) {
-  var watcher;
+  var watcher, fd;
+
+  if (process.platform == 'win32') {
+    fd = process.binding('os').openOSHandle(socket);
+  } else {
+    fd = socket;
+  }
 
   if (socket in watchers) {
     watcher = watchers[socket].watcher;
@@ -56,7 +62,7 @@ var channel = new dns.Channel({SOCK_STATE_CB: function(socket, read, write) {
     delete activeWatchers[socket];
     return;
   } else {
-    watcher.set(socket, read == 1, write == 1);
+    watcher.set(fd, read == 1, write == 1);
     watcher.start();
     activeWatchers[socket] = watcher;
   }

src/node_os.cc

@@ -9,6 +9,8 @@
 #include <string.h>
 
 #ifdef __MINGW32__
+# include <io.h>
+
 # include <platform_win32.h>
 # include <platform_win32_winsock.h>
 #endif
@@ -138,6 +140,20 @@ static Handle<Value> GetLoadAvg(const Arguments& args) {
   return scope.Close(loads);
 }
 
+#ifdef __MINGW32__
+static Handle<Value> OpenOSHandle(const Arguments& args) {
+  HandleScope scope;
+
+  intptr_t handle = args[0]->IntegerValue();
+
+  int fd = _open_osfhandle(handle, 0);
+  if (fd < 0)
+    return ThrowException(ErrnoException(errno, "_open_osfhandle"));
+
+  return scope.Close(Integer::New(fd));
+}
+#endif // __MINGW32__
+
 void OS::Initialize(v8::Handle<v8::Object> target) {
   HandleScope scope;
 
@@ -149,6 +165,10 @@ void OS::Initialize(v8::Handle<v8::Object> target) {
   NODE_SET_METHOD(target, "getCPUs", GetCPUInfo);
   NODE_SET_METHOD(target, "getOSType", GetOSType);
   NODE_SET_METHOD(target, "getOSRelease", GetOSRelease);
+
+#ifdef __MINGW32__
+  NODE_SET_METHOD(target, "openOSHandle", OpenOSHandle);
+#endif
 }