qmp: add DEVICE_TRAY_MOVED event

It's emitted whenever the tray is moved by the guest or by HMP/QMP
commands.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>

QMP/qmp-events.txt

@@ -26,6 +26,24 @@ Example:
 Note: If action is "stop", a STOP event will eventually follow the
 BLOCK_IO_ERROR event.
 
+DEVICE_TRAY_MOVED
+-----------------
+
+It's emitted whenever the tray of a removable device is moved by the guest
+or by HMP/QMP commands.
+
+Data:
+
+- "device": device name (json-string)
+- "tray-open": true if the tray has been opened or false if it has been closed
+               (json-bool)
+
+{ "event": "DEVICE_TRAY_MOVED",
+  "data": { "device": "ide1-cd0",
+            "tray-open": true
+  },
+  "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
+
 RESET
 -----
 

block.c

@@ -972,10 +972,30 @@ void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
     qobject_decref(data);
 }
 
+static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected)
+{
+    QObject *data;
+
+    data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }",
+                              bdrv_get_device_name(bs), ejected);
+    monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data);
+
+    qobject_decref(data);
+}
+
 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
 {
     if (bs->dev_ops && bs->dev_ops->change_media_cb) {
+        bool tray_was_closed = !bdrv_dev_is_tray_open(bs);
         bs->dev_ops->change_media_cb(bs->dev_opaque, load);
+        if (tray_was_closed) {
+            /* tray open */
+            bdrv_emit_qmp_eject_event(bs, true);
+        }
+        if (load) {
+            /* tray close */
+            bdrv_emit_qmp_eject_event(bs, false);
+        }
     }
 }
 
@@ -3616,6 +3636,10 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag)
     if (drv && drv->bdrv_eject) {
         drv->bdrv_eject(bs, eject_flag);
     }
+
+    if (bs->device_name[0] != '\0') {
+        bdrv_emit_qmp_eject_event(bs, eject_flag);
+    }
 }
 
 /**

monitor.c

@@ -485,6 +485,9 @@ void monitor_protocol_event(MonitorEvent event, QObject *data)
         case QEVENT_BLOCK_JOB_CANCELLED:
             event_name = "BLOCK_JOB_CANCELLED";
             break;
+        case QEVENT_DEVICE_TRAY_MOVED:
+             event_name = "DEVICE_TRAY_MOVED";
+            break;
         default:
             abort();
             break;

monitor.h

@@ -38,6 +38,7 @@ typedef enum MonitorEvent {
     QEVENT_SPICE_DISCONNECTED,
     QEVENT_BLOCK_JOB_COMPLETED,
     QEVENT_BLOCK_JOB_CANCELLED,
+    QEVENT_DEVICE_TRAY_MOVED,
     QEVENT_MAX,
 } MonitorEvent;