qemu: monitor: Add functions for object hot-add/remove

To allow live modification of device backends in qemu libvirt needs to
be able to hot-add/remove "objects". Add monitor backend functions to
allow this.

This function will be used for hot-add/remove of RNG backends,
IOThreads, memory backing objects, etc.

src/qemu/qemu_monitor.c

@@ -3132,6 +3132,54 @@ int qemuMonitorAddDevice(qemuMonitorPtr mon,
     return qemuMonitorAddDeviceWithFd(mon, devicestr, -1, NULL);
 }
 
+
+/**
+ * qemuMonitorAddObject:
+ * @mon: Pointer to monitor object
+ * @type: Type name of object to add
+ * @objalias: Alias of the new object
+ * @props: Optional arguments for the given type. The object is consumed and
+ *         should not be referenced by the caller after this function returns.
+ *
+ * Returns 0 on success -1 on error.
+ */
+int
+qemuMonitorAddObject(qemuMonitorPtr mon,
+                     const char *type,
+                     const char *objalias,
+                     virJSONValuePtr props)
+{
+    VIR_DEBUG("mon=%p type=%s objalias=%s props=%p",
+              mon, type, objalias, props);
+    int ret = -1;
+
+    if (mon->json)
+        ret = qemuMonitorJSONAddObject(mon, type, objalias, props);
+    else
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("object adding requires JSON monitor"));
+
+    return ret;
+}
+
+
+int
+qemuMonitorDelObject(qemuMonitorPtr mon,
+                     const char *objalias)
+{
+    VIR_DEBUG("mon=%p objalias=%s", mon, objalias);
+    int ret = -1;
+
+    if (mon->json)
+        ret = qemuMonitorJSONDelObject(mon, objalias);
+    else
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+                       _("object deletion requires JSON monitor"));
+
+    return ret;
+}
+
+
 int qemuMonitorAddDrive(qemuMonitorPtr mon,
                         const char *drivestr)
 {

src/qemu/qemu_monitor.h

@@ -672,6 +672,14 @@ int qemuMonitorAddDeviceWithFd(qemuMonitorPtr mon,
 int qemuMonitorDelDevice(qemuMonitorPtr mon,
                          const char *devalias);
 
+int qemuMonitorAddObject(qemuMonitorPtr mon,
+                         const char *type,
+                         const char *objalias,
+                         virJSONValuePtr props);
+
+int qemuMonitorDelObject(qemuMonitorPtr mon,
+                         const char *objalias);
+
 int qemuMonitorAddDrive(qemuMonitorPtr mon,
                         const char *drivestr);
 

src/qemu/qemu_monitor_json.c

@@ -3561,6 +3561,63 @@ int qemuMonitorJSONAddDevice(qemuMonitorPtr mon,
 }
 
 
+int qemuMonitorJSONAddObject(qemuMonitorPtr mon,
+                             const char *type,
+                             const char *objalias,
+                             virJSONValuePtr props)
+{
+    int ret = -1;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+
+    cmd = qemuMonitorJSONMakeCommand("object-add",
+                                     "s:qom-type", type,
+                                     "s:id", objalias,
+                                     "A:props", props,
+                                     NULL);
+    if (!cmd)
+        goto cleanup;
+
+     /* @props is part of @cmd now. Avoid double free */
+    props = NULL;
+
+    ret = qemuMonitorJSONCommand(mon, cmd, &reply);
+
+    if (ret == 0)
+        ret = qemuMonitorJSONCheckError(cmd, reply);
+
+ cleanup:
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    virJSONValueFree(props);
+    return ret;
+}
+
+
+int qemuMonitorJSONDelObject(qemuMonitorPtr mon,
+                             const char *objalias)
+{
+    int ret;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+
+    cmd = qemuMonitorJSONMakeCommand("object-del",
+                                     "s:id", objalias,
+                                     NULL);
+    if (!cmd)
+        return -1;
+
+    ret = qemuMonitorJSONCommand(mon, cmd, &reply);
+
+    if (ret == 0)
+        ret = qemuMonitorJSONCheckError(cmd, reply);
+
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}
+
+
 int qemuMonitorJSONAddDrive(qemuMonitorPtr mon,
                             const char *drivestr)
 {

src/qemu/qemu_monitor_json.h

@@ -229,6 +229,14 @@ int qemuMonitorJSONAddDevice(qemuMonitorPtr mon,
 int qemuMonitorJSONDelDevice(qemuMonitorPtr mon,
                              const char *devalias);
 
+int qemuMonitorJSONAddObject(qemuMonitorPtr mon,
+                             const char *type,
+                             const char *objalias,
+                             virJSONValuePtr props);
+
+int qemuMonitorJSONDelObject(qemuMonitorPtr mon,
+                             const char *objalias);
+
 int qemuMonitorJSONAddDrive(qemuMonitorPtr mon,
                             const char *drivestr);