QMP: Introduce VNC_CONNECTED event

It's emitted when a VNC client connects to QEMU, client's information
such as port and IP address are provided.

Note that this event is emitted right when the connection is
established. This means that it happens before authentication
procedure and session initialization.

Event example:

{ "event": "VNC_CONNECTED",
    "timestamp": { "seconds": 1262976601, "microseconds": 975795 },
    "data": {
        "server": { "auth": "sasl", "family": "ipv4",
                    "service": "5901", "host": "0.0.0.0" },
        "client": { "family": "ipv4", "service": "58425",
                    "host": "127.0.0.1" } } }

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

QMP/qmp-events.txt

@@ -24,3 +24,10 @@ Data: None.
 
 Description: Issued when the Virtual Machine enters debug mode.
 Data: None.
+
+4 VNC_CONNECTED
+---------------
+
+Description: Issued when a VNC client establishes a connection.
+Data: 'server' and 'client' keys with the same keys as 'query-vnc',
+except that authentication ID is not provided.

monitor.c

@@ -357,6 +357,9 @@ void monitor_protocol_event(MonitorEvent event, QObject *data)
         case QEVENT_STOP:
             event_name = "STOP";
             break;
+        case QEVENT_VNC_CONNECTED:
+            event_name = "VNC_CONNECTED";
+            break;
         default:
             abort();
             break;

monitor.h

@@ -20,6 +20,7 @@ typedef enum MonitorEvent {
     QEVENT_RESET,
     QEVENT_POWERDOWN,
     QEVENT_STOP,
+    QEVENT_VNC_CONNECTED,
     QEVENT_MAX,
 } MonitorEvent;
 

vnc.c

@@ -269,6 +269,30 @@ static void vnc_client_cache_addr(VncState *client)
     client->info = QOBJECT(qdict);
 }
 
+static void vnc_qmp_event(VncState *vs, MonitorEvent event)
+{
+    QDict *server;
+    QObject *data;
+
+    if (!vs->info) {
+        return;
+    }
+
+    server = qdict_new();
+    if (vnc_server_info_put(server) < 0) {
+        QDECREF(server);
+        return;
+    }
+
+    data = qobject_from_jsonf("{ 'client': %p, 'server': %p }",
+                              vs->info, QOBJECT(server));
+
+    monitor_protocol_event(event, data);
+
+    qobject_incref(vs->info);
+    qobject_decref(data);
+}
+
 static void info_vnc_iter(QObject *obj, void *opaque)
 {
     QDict *client;
@@ -2396,6 +2420,7 @@ static void vnc_connect(VncDisplay *vd, int csock)
     qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
 
     vnc_client_cache_addr(vs);
+    vnc_qmp_event(vs, QEVENT_VNC_CONNECTED);
 
     vs->vd = vd;
     vs->ds = vd->ds;