Add support for an explicit RTC change event

This introduces a new event type

   VIR_DOMAIN_EVENT_ID_RTC_CHANGE

This event includes the new UTC offset measured in seconds.
Thus there is a new callback definition for this event type

 typedef void (*virConnectDomainEventRTCChangeCallback)(virConnectPtr conn,
                                                        virDomainPtr dom,
                                                        long long utcoffset,
                                                        void *opaque);

If the guest XML configuration for the <clock> is set to
offset='variable', then the XML will automatically be
updated with the new UTC offset value. This ensures that
during migration/save/restore the new offset is preserved.

* daemon/remote.c: Dispatch RTC change events to client
* examples/domain-events/events-c/event-test.c: Watch for
  RTC change events
* include/libvirt/libvirt.h.in: Define new RTC change event ID
  and callback signature
* src/conf/domain_event.c, src/conf/domain_event.h,
  src/libvirt_private.syms: Extend API to handle RTC change events
* src/qemu/qemu_driver.c: Connect to the QEMU monitor event
  for RTC changes and emit a libvirt RTC change event
* src/remote/remote_driver.c: Receive and dispatch RTC change
  events to application
* src/remote/remote_protocol.x: Wire protocol definition for
  RTC change events
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c: Watch for RTC_CHANGE event
  from QEMU monitor

daemon/remote.c

@@ -157,9 +157,40 @@ static int remoteRelayDomainEventReboot(virConnectPtr conn ATTRIBUTE_UNUSED,
 }
 
 
+static int remoteRelayDomainEventRTCChange(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                           virDomainPtr dom,
+                                           long long offset,
+                                           void *opaque)
+{
+    struct qemud_client *client = opaque;
+    remote_domain_event_rtc_change_msg data;
+
+    if (!client)
+        return -1;
+
+    REMOTE_DEBUG("Relaying domain rtc change event %s %d %lld", dom->name, dom->id, offset);
+
+    virMutexLock(&client->lock);
+
+    /* build return data */
+    memset(&data, 0, sizeof data);
+    make_nonnull_domain (&data.dom, dom);
+    data.offset = offset;
+
+    remoteDispatchDomainEventSend (client,
+                                   REMOTE_PROC_DOMAIN_EVENT_RTC_CHANGE,
+                                   (xdrproc_t)xdr_remote_domain_event_rtc_change_msg, &data);
+
+    virMutexUnlock(&client->lock);
+
+    return 0;
+}
+
+
 static virConnectDomainEventGenericCallback domainEventCallbacks[] = {
     VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventLifecycle),
     VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventReboot),
+    VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventRTCChange),
 };
 
 verify(ARRAY_CARDINALITY(domainEventCallbacks) == VIR_DOMAIN_EVENT_ID_LAST);

daemon/remote_dispatch_table.h

@@ -852,3 +852,8 @@
     .args_filter = (xdrproc_t) xdr_void,
     .ret_filter = (xdrproc_t) xdr_void,
 },
+{   /* Async event DomainEventRtcChange => 170 */
+    .fn = NULL,
+    .args_filter = (xdrproc_t) xdr_void,
+    .ret_filter = (xdrproc_t) xdr_void,
+},

examples/domain-events/events-c/event-test.c

@@ -182,6 +182,17 @@ static int myDomainEventRebootCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
     return 0;
 }
 
+static int myDomainEventRTCChangeCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                          virDomainPtr dom,
+                                          long long offset,
+                                          void *opaque ATTRIBUTE_UNUSED)
+{
+    printf("%s EVENT: Domain %s(%d) rtc change %lld\n", __func__, virDomainGetName(dom),
+           virDomainGetID(dom), offset);
+
+    return 0;
+}
+
 static void myFreeFunc(void *opaque)
 {
     char *str = opaque;
@@ -300,6 +311,7 @@ int main(int argc, char **argv)
     int callback1ret = -1;
     int callback2ret = -1;
     int callback3ret = -1;
+    int callback4ret = -1;
 
     struct sigaction action_stop = {
         .sa_handler = stop
@@ -342,10 +354,16 @@ int main(int argc, char **argv)
                                                     VIR_DOMAIN_EVENT_ID_REBOOT,
                                                     VIR_DOMAIN_EVENT_CALLBACK(myDomainEventRebootCallback),
                                                     strdup("callback reboot"), myFreeFunc);
+    callback4ret = virConnectDomainEventRegisterAny(dconn,
+                                                    NULL,
+                                                    VIR_DOMAIN_EVENT_ID_RTC_CHANGE,
+                                                    VIR_DOMAIN_EVENT_CALLBACK(myDomainEventRTCChangeCallback),
+                                                    strdup("callback rtcchange"), myFreeFunc);
 
     if ((callback1ret != -1) &&
         (callback2ret != -1) &&
-        (callback3ret != -1)) {
+        (callback3ret != -1) &&
+        (callback4ret != -1)) {
         while(run) {
             struct pollfd pfd = { .fd = h_fd,
                               .events = h_event,
@@ -384,6 +402,7 @@ int main(int argc, char **argv)
         virConnectDomainEventDeregister(dconn, myDomainEventCallback1);
         virConnectDomainEventDeregisterAny(dconn, callback2ret);
         virConnectDomainEventDeregisterAny(dconn, callback3ret);
+        virConnectDomainEventDeregisterAny(dconn, callback4ret);
 
     }
 

include/libvirt/libvirt.h.in

@@ -1863,6 +1863,21 @@ typedef void (*virConnectDomainEventGenericCallback)(virConnectPtr conn,
                                                      virDomainPtr dom,
                                                      void *opaque);
 
+/**
+ * virConnectDomainEventRTCChangeCallback:
+ * @conn: connection object
+ * @dom: domain on which the event occurred
+ * @utcoffset: the new RTC offset from UTC, measured in seconds
+ * @opaque: application specified data
+ *
+ * The callback signature to use when registering for an event of type
+ * VIR_DOMAIN_EVENT_ID_RTC_CHANGE with virConnectDomainEventRegisterAny()
+ */
+typedef void (*virConnectDomainEventRTCChangeCallback)(virConnectPtr conn,
+                                                       virDomainPtr dom,
+                                                       long long utcoffset,
+                                                       void *opaque);
+
 /**
  * VIR_DOMAIN_EVENT_CALLBACK:
  *
@@ -1875,6 +1890,7 @@ typedef void (*virConnectDomainEventGenericCallback)(virConnectPtr conn,
 typedef enum {
     VIR_DOMAIN_EVENT_ID_LIFECYCLE = 0,       /* virConnectDomainEventCallback */
     VIR_DOMAIN_EVENT_ID_REBOOT = 1,          /* virConnectDomainEventGenericCallback */
+    VIR_DOMAIN_EVENT_ID_RTC_CHANGE = 2,      /* virConnectDomainEventRTCChangeCallback */
 
     /*
      * NB: this enum value will increase over time as new events are

python/generator.py

@@ -170,6 +170,7 @@ skipped_types = {
 #    'int *': "usually a return type",
      'virConnectDomainEventCallback': "No function types in python",
      'virConnectDomainEventGenericCallback': "No function types in python",
+     'virConnectDomainEventRTCChangeCallback': "No function types in python",
      'virEventAddHandleFunc': "No function types in python",
 }
 

src/conf/domain_event.c

@@ -64,6 +64,9 @@ struct _virDomainEvent {
             int type;
             int detail;
         } lifecycle;
+        struct {
+            long long offset;
+        } rtcChange;
     } data;
 };
 
@@ -534,6 +537,31 @@ virDomainEventPtr virDomainEventRebootNewFromObj(virDomainObjPtr obj)
                                      obj->def->id, obj->def->name, obj->def->uuid);
 }
 
+virDomainEventPtr virDomainEventRTCChangeNewFromDom(virDomainPtr dom,
+                                                    long long offset)
+{
+    virDomainEventPtr ev =
+        virDomainEventNewInternal(VIR_DOMAIN_EVENT_ID_RTC_CHANGE,
+                                  dom->id, dom->name, dom->uuid);
+
+    if (ev)
+        ev->data.rtcChange.offset = offset;
+
+    return ev;
+}
+virDomainEventPtr virDomainEventRTCChangeNewFromObj(virDomainObjPtr obj,
+                                                    long long offset)
+{
+    virDomainEventPtr ev =
+        virDomainEventNewInternal(VIR_DOMAIN_EVENT_ID_RTC_CHANGE,
+                                  obj->def->id, obj->def->name, obj->def->uuid);
+
+    if (ev)
+        ev->data.rtcChange.offset = offset;
+
+    return ev;
+}
+
 /**
  * virDomainEventQueueFree:
  * @queue: pointer to the queue
@@ -644,6 +672,12 @@ void virDomainEventDispatchDefaultFunc(virConnectPtr conn,
              cbopaque);
         break;
 
+    case VIR_DOMAIN_EVENT_ID_RTC_CHANGE:
+        ((virConnectDomainEventRTCChangeCallback)cb)(conn, dom,
+                                                     event->data.rtcChange.offset,
+                                                     cbopaque);
+        break;
+
     default:
         VIR_WARN("Unexpected event ID %d", event->eventID);
         break;

src/conf/domain_event.h

@@ -115,6 +115,9 @@ virDomainEventPtr virDomainEventNewFromDef(virDomainDefPtr def, int type, int de
 virDomainEventPtr virDomainEventRebootNewFromDom(virDomainPtr dom);
 virDomainEventPtr virDomainEventRebootNewFromObj(virDomainObjPtr obj);
 
+virDomainEventPtr virDomainEventRTCChangeNewFromDom(virDomainPtr dom, long long offset);
+virDomainEventPtr virDomainEventRTCChangeNewFromObj(virDomainObjPtr obj, long long offset);
+
 int virDomainEventQueuePush(virDomainEventQueuePtr evtQueue,
                             virDomainEventPtr event);
 

src/libvirt_private.syms

@@ -216,6 +216,8 @@ virDomainEventNewFromObj;
 virDomainEventNewFromDef;
 virDomainEventRebootNewFromDom;
 virDomainEventRebootNewFromObj;
+virDomainEventRTCChangeNewFromDom;
+virDomainEventRTCChangeNewFromObj;
 virDomainEventFree;
 virDomainEventDispatchDefaultFunc;
 virDomainEventDispatch;

src/qemu/qemu_driver.c

@@ -886,10 +886,40 @@ qemuHandleDomainReset(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 }
 
 
+static int
+qemuHandleDomainRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
+                          virDomainObjPtr vm,
+                          long long offset)
+{
+    struct qemud_driver *driver = qemu_driver;
+    virDomainEventPtr event;
+
+    virDomainObjLock(vm);
+    event = virDomainEventRTCChangeNewFromObj(vm, offset);
+
+    if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE)
+        vm->def->clock.data.adjustment = offset;
+
+    if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0)
+        VIR_WARN0("unable to save domain status with RTC change");
+
+    virDomainObjUnlock(vm);
+
+    if (event) {
+        qemuDriverLock(driver);
+        qemuDomainEventQueue(driver, event);
+        qemuDriverUnlock(driver);
+    }
+
+    return 0;
+}
+
+
 static qemuMonitorCallbacks monitorCallbacks = {
     .eofNotify = qemuHandleMonitorEOF,
     .diskSecretLookup = findVolumeQcowPassphrase,
     .domainReset = qemuHandleDomainReset,
+    .domainRTCChange = qemuHandleDomainRTCChange,
 };
 
 static int

src/qemu/qemu_monitor.c

@@ -791,6 +791,21 @@ int qemuMonitorEmitStop(qemuMonitorPtr mon)
 }
 
 
+int qemuMonitorEmitRTCChange(qemuMonitorPtr mon, long long offset)
+{
+    int ret = -1;
+    VIR_DEBUG("mon=%p", mon);
+
+    qemuMonitorRef(mon);
+    qemuMonitorUnlock(mon);
+    if (mon->cb && mon->cb->domainRTCChange)
+        ret = mon->cb->domainRTCChange(mon, mon->vm, offset);
+    qemuMonitorLock(mon);
+    qemuMonitorUnref(mon);
+    return ret;
+}
+
+
 int qemuMonitorSetCapabilities(qemuMonitorPtr mon)
 {
     int ret;

src/qemu/qemu_monitor.h

@@ -86,6 +86,9 @@ struct _qemuMonitorCallbacks {
                            virDomainObjPtr vm);
     int (*domainStop)(qemuMonitorPtr mon,
                       virDomainObjPtr vm);
+    int (*domainRTCChange)(qemuMonitorPtr mon,
+                           virDomainObjPtr vm,
+                           long long offset);
 };
 
 
@@ -122,6 +125,7 @@ int qemuMonitorEmitShutdown(qemuMonitorPtr mon);
 int qemuMonitorEmitReset(qemuMonitorPtr mon);
 int qemuMonitorEmitPowerdown(qemuMonitorPtr mon);
 int qemuMonitorEmitStop(qemuMonitorPtr mon);
+int qemuMonitorEmitRTCChange(qemuMonitorPtr mon, long long offset);
 
 int qemuMonitorStartCPUs(qemuMonitorPtr mon,
                          virConnectPtr conn);

src/qemu/qemu_monitor_json.c

@@ -49,6 +49,7 @@ static void qemuMonitorJSONHandleShutdown(qemuMonitorPtr mon, virJSONValuePtr da
 static void qemuMonitorJSONHandleReset(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandlePowerdown(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandleStop(qemuMonitorPtr mon, virJSONValuePtr data);
+static void qemuMonitorJSONHandleRTCChange(qemuMonitorPtr mon, virJSONValuePtr data);
 
 struct {
     const char *type;
@@ -58,6 +59,7 @@ struct {
     { "RESET", qemuMonitorJSONHandleReset, },
     { "POWERDOWN", qemuMonitorJSONHandlePowerdown, },
     { "STOP", qemuMonitorJSONHandleStop, },
+    { "RTC_CHANGE", qemuMonitorJSONHandleRTCChange, },
 };
 
 
@@ -495,6 +497,16 @@ static void qemuMonitorJSONHandleStop(qemuMonitorPtr mon, virJSONValuePtr data A
     qemuMonitorEmitStop(mon);
 }
 
+static void qemuMonitorJSONHandleRTCChange(qemuMonitorPtr mon, virJSONValuePtr data)
+{
+    long long offset = 0;
+    if (virJSONValueObjectGetNumberLong(data, "offset", &offset) < 0) {
+        VIR_WARN0("missing offset in RTC change event");
+        offset = 0;
+    }
+    qemuMonitorEmitRTCChange(mon, offset);
+}
+
 
 int
 qemuMonitorJSONSetCapabilities(qemuMonitorPtr mon)

src/remote/remote_driver.c

@@ -6940,6 +6940,33 @@ remoteDomainReadEventReboot(virConnectPtr conn, XDR *xdr)
 }
 
 
+static virDomainEventPtr
+remoteDomainReadEventRTCChange(virConnectPtr conn, XDR *xdr)
+{
+    remote_domain_event_rtc_change_msg msg;
+    virDomainPtr dom;
+    virDomainEventPtr event = NULL;
+    memset (&msg, 0, sizeof msg);
+
+    /* unmarshall parameters, and process it*/
+    if (! xdr_remote_domain_event_rtc_change_msg(xdr, &msg) ) {
+        error (conn, VIR_ERR_RPC,
+               _("unable to demarshall reboot event"));
+        return NULL;
+    }
+
+    dom = get_nonnull_domain(conn,msg.dom);
+    if (!dom)
+        return NULL;
+
+    event = virDomainEventRTCChangeNewFromDom(dom, msg.offset);
+    xdr_free ((xdrproc_t) &xdr_remote_domain_event_rtc_change_msg, (char *) &msg);
+
+    virDomainFree(dom);
+    return event;
+}
+
+
 static virDrvOpenStatus ATTRIBUTE_NONNULL (1)
 remoteSecretOpen (virConnectPtr conn,
                   virConnectAuthPtr auth,
@@ -8487,6 +8514,10 @@ processCallDispatchMessage(virConnectPtr conn, struct private_data *priv,
         event = remoteDomainReadEventReboot(conn, xdr);
         break;
 
+    case REMOTE_PROC_DOMAIN_EVENT_RTC_CHANGE:
+        event = remoteDomainReadEventRTCChange(conn, xdr);
+        break;
+
     default:
         DEBUG("Unexpected event proc %d", hdr->proc);
         break;

src/remote/remote_protocol.c

@@ -3059,6 +3059,17 @@ xdr_remote_domain_event_reboot_msg (XDR *xdrs, remote_domain_event_reboot_msg *o
         return TRUE;
 }
 
+bool_t
+xdr_remote_domain_event_rtc_change_msg (XDR *xdrs, remote_domain_event_rtc_change_msg *objp)
+{
+
+         if (!xdr_remote_nonnull_domain (xdrs, &objp->dom))
+                 return FALSE;
+         if (!xdr_int64_t (xdrs, &objp->offset))
+                 return FALSE;
+        return TRUE;
+}
+
 bool_t
 xdr_remote_procedure (XDR *xdrs, remote_procedure *objp)
 {

src/remote/remote_protocol.h

@@ -1732,6 +1732,12 @@ struct remote_domain_event_reboot_msg {
         remote_nonnull_domain dom;
 };
 typedef struct remote_domain_event_reboot_msg remote_domain_event_reboot_msg;
+
+struct remote_domain_event_rtc_change_msg {
+        remote_nonnull_domain dom;
+        int64_t offset;
+};
+typedef struct remote_domain_event_rtc_change_msg remote_domain_event_rtc_change_msg;
 #define REMOTE_PROGRAM 0x20008086
 #define REMOTE_PROTOCOL_VERSION 1
 
@@ -1905,6 +1911,7 @@ enum remote_procedure {
         REMOTE_PROC_DOMAIN_EVENTS_REGISTER_ANY = 167,
         REMOTE_PROC_DOMAIN_EVENTS_DEREGISTER_ANY = 168,
         REMOTE_PROC_DOMAIN_EVENT_REBOOT = 169,
+        REMOTE_PROC_DOMAIN_EVENT_RTC_CHANGE = 170,
 };
 typedef enum remote_procedure remote_procedure;
 
@@ -2219,6 +2226,7 @@ extern  bool_t xdr_remote_domain_migrate_set_max_downtime_args (XDR *, remote_do
 extern  bool_t xdr_remote_domain_events_register_any_args (XDR *, remote_domain_events_register_any_args*);
 extern  bool_t xdr_remote_domain_events_deregister_any_args (XDR *, remote_domain_events_deregister_any_args*);
 extern  bool_t xdr_remote_domain_event_reboot_msg (XDR *, remote_domain_event_reboot_msg*);
+extern  bool_t xdr_remote_domain_event_rtc_change_msg (XDR *, remote_domain_event_rtc_change_msg*);
 extern  bool_t xdr_remote_procedure (XDR *, remote_procedure*);
 extern  bool_t xdr_remote_message_type (XDR *, remote_message_type*);
 extern  bool_t xdr_remote_message_status (XDR *, remote_message_status*);
@@ -2507,6 +2515,7 @@ extern bool_t xdr_remote_domain_migrate_set_max_downtime_args ();
 extern bool_t xdr_remote_domain_events_register_any_args ();
 extern bool_t xdr_remote_domain_events_deregister_any_args ();
 extern bool_t xdr_remote_domain_event_reboot_msg ();
+extern bool_t xdr_remote_domain_event_rtc_change_msg ();
 extern bool_t xdr_remote_procedure ();
 extern bool_t xdr_remote_message_type ();
 extern bool_t xdr_remote_message_status ();

src/remote/remote_protocol.x

@@ -1540,6 +1540,11 @@ struct remote_domain_event_reboot_msg {
     remote_nonnull_domain dom;
 };
 
+struct remote_domain_event_rtc_change_msg {
+    remote_nonnull_domain dom;
+    hyper offset;
+};
+
 /*----- Protocol. -----*/
 
 /* Define the program number, protocol version and procedure numbers here. */
@@ -1731,7 +1736,8 @@ enum remote_procedure {
     REMOTE_PROC_DOMAIN_MIGRATE_SET_MAX_DOWNTIME = 166,
     REMOTE_PROC_DOMAIN_EVENTS_REGISTER_ANY = 167,
     REMOTE_PROC_DOMAIN_EVENTS_DEREGISTER_ANY = 168,
-    REMOTE_PROC_DOMAIN_EVENT_REBOOT = 169
+    REMOTE_PROC_DOMAIN_EVENT_REBOOT = 169,
+    REMOTE_PROC_DOMAIN_EVENT_RTC_CHANGE = 170
 
     /*
      * Notice how the entries are grouped in sets of 10 ?