Fix QEMU driver custom domain status XML extensions

Invoking the virConnectGetCapabilities() method causes the QEMU
driver to rebuild its internal capabilities object. Unfortunately
it was forgetting to register the custom domain status XML hooks
again.

To avoid this kind of error in the future, the code which builds
capabilities is refactored into one single method, which can be
called from all locations, ensuring reliable rebuilds.

* src/qemu/qemu_driver.c: Fix rebuilding of capabilities XML and
  guarentee it is always consistent

src/qemu/qemu_driver.c

@@ -891,34 +891,6 @@ qemuReconnectDomains(struct qemud_driver *driver)
 }
 
 
-static int
-qemudSecurityCapsInit(virSecurityDriverPtr secdrv,
-                      virCapsPtr caps)
-{
-    const char *doi, *model;
-
-    doi = virSecurityDriverGetDOI(secdrv);
-    model = virSecurityDriverGetModel(secdrv);
-
-    caps->host.secModel.model = strdup(model);
-    if (!caps->host.secModel.model) {
-        virReportOOMError(NULL);
-        return -1;
-    }
-
-    caps->host.secModel.doi = strdup(doi);
-    if (!caps->host.secModel.doi) {
-        virReportOOMError(NULL);
-        return -1;
-    }
-
-    VIR_DEBUG("Initialized caps for security driver \"%s\" with "
-              "DOI \"%s\"", model, doi);
-
-    return 0;
-}
-
-
 static int
 qemudSecurityInit(struct qemud_driver *qemud_drv)
 {
@@ -940,15 +912,52 @@ qemudSecurityInit(struct qemud_driver *qemud_drv)
     qemud_drv->securityDriver = security_drv;
 
     VIR_INFO("Initialized security driver %s", security_drv->name);
-
-    /*
-     * Add security policy host caps now that the security driver is
-     * initialized.
-     */
-    return qemudSecurityCapsInit(security_drv, qemud_drv->caps);
+    return 0;
 }
 
 
+static virCapsPtr
+qemuCreateCapabilities(virCapsPtr oldcaps,
+                       virSecurityDriverPtr secDriver)
+{
+    virCapsPtr caps;
+
+    /* Basic host arch / guest machine capabilities */
+    if (!(caps = qemudCapsInit(oldcaps))) {
+        virReportOOMError(NULL);
+        return NULL;
+    }
+
+    /* Domain XML parser hooks */
+    caps->privateDataAllocFunc = qemuDomainObjPrivateAlloc;
+    caps->privateDataFreeFunc = qemuDomainObjPrivateFree;
+    caps->privateDataXMLFormat = qemuDomainObjPrivateXMLFormat;
+    caps->privateDataXMLParse = qemuDomainObjPrivateXMLParse;
+
+
+    /* Security driver data */
+    if (secDriver) {
+        const char *doi, *model;
+
+        doi = virSecurityDriverGetDOI(secDriver);
+        model = virSecurityDriverGetModel(secDriver);
+
+        if (!(caps->host.secModel.model = strdup(model)))
+            goto no_memory;
+        if (!(caps->host.secModel.doi = strdup(doi)))
+            goto no_memory;
+
+        VIR_DEBUG("Initialized caps for security driver \"%s\" with "
+                  "DOI \"%s\"", model, doi);
+    }
+
+    return caps;
+
+no_memory:
+    virReportOOMError(NULL);
+    virCapabilitiesFree(caps);
+    return NULL;
+}
 
 /**
  * qemudStartup:
@@ -1074,13 +1083,12 @@ qemudStartup(int privileged) {
                  virStrerror(-rc, buf, sizeof(buf)));
     }
 
-    if ((qemu_driver->caps = qemudCapsInit(NULL)) == NULL)
-        goto out_of_memory;
+    if (qemudSecurityInit(qemu_driver) < 0)
+        goto error;
 
-    qemu_driver->caps->privateDataAllocFunc = qemuDomainObjPrivateAlloc;
-    qemu_driver->caps->privateDataFreeFunc = qemuDomainObjPrivateFree;
-    qemu_driver->caps->privateDataXMLFormat = qemuDomainObjPrivateXMLFormat;
-    qemu_driver->caps->privateDataXMLParse = qemuDomainObjPrivateXMLParse;
+    if ((qemu_driver->caps = qemuCreateCapabilities(NULL,
+                                                    qemu_driver->securityDriver)) == NULL)
+        goto error;
 
     if ((qemu_driver->activePciHostdevs = pciDeviceListNew(NULL)) == NULL)
         goto error;
@@ -1104,10 +1112,6 @@ qemudStartup(int privileged) {
         }
     }
 
-    if (qemudSecurityInit(qemu_driver) < 0) {
-        goto error;
-    }
-
     /* If hugetlbfs is present, then we need to create a sub-directory within
      * it, since we can't assume the root mount point has permissions that
      * will let our spawned QEMU instances use it.
@@ -3258,15 +3262,12 @@ static char *qemudGetCapabilities(virConnectPtr conn) {
     char *xml = NULL;
 
     qemuDriverLock(driver);
-    if ((caps = qemudCapsInit(qemu_driver->caps)) == NULL)
-        goto no_memory;
 
-    caps->privateDataAllocFunc = qemuDomainObjPrivateAlloc;
-    caps->privateDataFreeFunc = qemuDomainObjPrivateFree;
-
-    if (qemu_driver->securityDriver &&
-        qemudSecurityCapsInit(qemu_driver->securityDriver, caps) < 0)
-        goto no_memory;
+    if ((caps = qemuCreateCapabilities(qemu_driver->caps,
+                                       qemu_driver->securityDriver)) == NULL) {
+        virCapabilitiesFree(caps);
+        goto cleanup;
+    }
 
     virCapabilitiesFree(qemu_driver->caps);
     qemu_driver->caps = caps;
@@ -3278,11 +3279,6 @@ cleanup:
     qemuDriverUnlock(driver);
 
     return xml;
-
-no_memory:
-    virCapabilitiesFree(caps);
-    virReportOOMError(conn);
-    goto cleanup;
 }