Add missing checks for NULL in domain lock manager

The domain lock manager forgot to include a bunch of checks
for NULL which could occur on OOM

* src/locking/domain_lock.c: Add checks for NULL

src/locking/domain_lock.c

@@ -157,10 +157,13 @@ int virDomainLockProcessStart(virLockManagerPluginPtr plugin,
                               virDomainObjPtr dom,
                               bool paused)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, true);
+    virLockManagerPtr lock;
     int ret;
     int flags = VIR_LOCK_MANAGER_ACQUIRE_RESTRICT;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, true)))
+        return -1;
+
     if (paused)
         flags |= VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY;
 
@@ -175,9 +178,13 @@ int virDomainLockProcessPause(virLockManagerPluginPtr plugin,
                               virDomainObjPtr dom,
                               char **state)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, true);
-    int ret = virLockManagerRelease(lock, state, 0);
+    virLockManagerPtr lock;
+    int ret;
+
+    if (!(lock = virDomainLockManagerNew(plugin, dom, true)))
+        return -1;
 
+    ret = virLockManagerRelease(lock, state, 0);
     virLockManagerFree(lock);
 
     return ret;
@@ -187,9 +194,13 @@ int virDomainLockProcessResume(virLockManagerPluginPtr plugin,
                                virDomainObjPtr dom,
                                const char *state)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, true);
-    int ret = virLockManagerAcquire(lock, state, 0);
+    virLockManagerPtr lock;
+    int ret;
+
+    if (!(lock = virDomainLockManagerNew(plugin, dom, true)))
+        return -1;
 
+    ret = virLockManagerAcquire(lock, state, 0);
     virLockManagerFree(lock);
 
     return ret;
@@ -199,9 +210,13 @@ int virDomainLockProcessInquire(virLockManagerPluginPtr plugin,
                                 virDomainObjPtr dom,
                                 char **state)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, true);
-    int ret = virLockManagerInquire(lock, state, 0);
+    virLockManagerPtr lock;
+    int ret;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, true)))
+        return -1;
+
+    ret = virLockManagerInquire(lock, state, 0);
     virLockManagerFree(lock);
 
     return ret;
@@ -212,9 +227,12 @@ int virDomainLockDiskAttach(virLockManagerPluginPtr plugin,
                             virDomainObjPtr dom,
                             virDomainDiskDefPtr disk)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, false);
+    virLockManagerPtr lock;
     int ret = -1;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, false)))
+        return -1;
+
     if (virDomainLockManagerAddDisk(lock, disk) < 0)
         goto cleanup;
 
@@ -233,9 +251,12 @@ int virDomainLockDiskDetach(virLockManagerPluginPtr plugin,
                             virDomainObjPtr dom,
                             virDomainDiskDefPtr disk)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, false);
+    virLockManagerPtr lock;
     int ret = -1;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, false)))
+        return -1;
+
     if (virDomainLockManagerAddDisk(lock, disk) < 0)
         goto cleanup;
 
@@ -255,9 +276,12 @@ int virDomainLockLeaseAttach(virLockManagerPluginPtr plugin,
                              virDomainObjPtr dom,
                              virDomainLeaseDefPtr lease)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, false);
+    virLockManagerPtr lock;
     int ret = -1;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, false)))
+        return -1;
+
     if (virDomainLockManagerAddLease(lock, lease) < 0)
         goto cleanup;
 
@@ -276,9 +300,12 @@ int virDomainLockLeaseDetach(virLockManagerPluginPtr plugin,
                              virDomainObjPtr dom,
                              virDomainLeaseDefPtr lease)
 {
-    virLockManagerPtr lock = virDomainLockManagerNew(plugin, dom, false);
+    virLockManagerPtr lock;
     int ret = -1;
 
+    if (!(lock = virDomainLockManagerNew(plugin, dom, false)))
+        return -1;
+
     if (virDomainLockManagerAddLease(lock, lease) < 0)
         goto cleanup;