debug: avoid null dereference on uuid lookup api

Detected by Coverity.  Commit a98d8f0d tried to make uuid debugging
more robust, but missed some APIs.  And on the APIs that it visited,
the mere act of preparing the debug message ends up dereferencing
uuid prior to the null check.  Which means the APIs which are supposed
to gracefully reject NULL arguments now end up with SIGSEGV.

* src/libvirt.c (VIR_UUID_DEBUG): New macro.
(virDomainLookupByUUID, virDomainLookupByUUIDString)
(virNetworkLookupByUUID, virNetworkLookupByUUIDString)
(virStoragePoolLookupByUUID, virStoragePoolLookupByUUIDString)
(virSecretLookupByUUID, virSecretLookupByUUIDString)
(virNWFilterLookupByUUID, virNWFilterLookupByUUIDString): Avoid
null dereference.

src/libvirt.c

@@ -362,6 +362,22 @@ static struct gcry_thread_cbs virTLSThreadImpl = {
                             VIR_HAS_COMMA(__VA_ARGS__), \
                             __VA_ARGS__)
 
+/**
+ * VIR_UUID_DEBUG:
+ * @conn: connection
+ * @uuid: possibly null UUID array
+ */
+#define VIR_UUID_DEBUG(conn, uuid)                              \
+    do {                                                        \
+        if (uuid) {                                             \
+            char _uuidstr[VIR_UUID_STRING_BUFLEN];              \
+            virUUIDFormat(uuid, _uuidstr);                      \
+            VIR_DEBUG("conn=%p, uuid=%s", conn, _uuidstr);      \
+        } else {                                                \
+            VIR_DEBUG("conn=%p, uuid=(null)", conn);            \
+        }                                                       \
+    } while (0)
+
 /**
  * virInitialize:
  *
@@ -1876,10 +1892,7 @@ error:
 virDomainPtr
 virDomainLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
 {
-    char uuidstr[VIR_UUID_STRING_BUFLEN];
-    virUUIDFormat(uuid, uuidstr);
-
-    VIR_DEBUG("conn=%p, uuid=%s", conn, uuidstr);
+    VIR_UUID_DEBUG(conn, uuid);
 
     virResetLastError();
 
@@ -1922,7 +1935,7 @@ virDomainPtr
 virDomainLookupByUUIDString(virConnectPtr conn, const char *uuidstr)
 {
     unsigned char uuid[VIR_UUID_BUFLEN];
-    VIR_DEBUG("conn=%p, uuidstr=%s", conn, uuidstr);
+    VIR_DEBUG("conn=%p, uuidstr=%s", conn, NULLSTR(uuidstr));
 
     virResetLastError();
 
@@ -7493,10 +7506,7 @@ error:
 virNetworkPtr
 virNetworkLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
 {
-    char uuidstr[VIR_UUID_STRING_BUFLEN];
-    virUUIDFormat(uuid, uuidstr);
-
-    VIR_DEBUG("conn=%p, uuid=%s", conn, uuidstr);
+    VIR_UUID_DEBUG(conn, uuid);
 
     virResetLastError();
 
@@ -7539,7 +7549,7 @@ virNetworkPtr
 virNetworkLookupByUUIDString(virConnectPtr conn, const char *uuidstr)
 {
     unsigned char uuid[VIR_UUID_BUFLEN];
-    VIR_DEBUG("conn=%p, uuidstr=%s", conn, uuidstr);
+    VIR_DEBUG("conn=%p, uuidstr=%s", conn, NULLSTR(uuidstr));
 
     virResetLastError();
 
@@ -9235,7 +9245,7 @@ virStoragePoolPtr
 virStoragePoolLookupByUUID(virConnectPtr conn,
                            const unsigned char *uuid)
 {
-    VIR_DEBUG("conn=%p, uuid=%s", conn, uuid);
+    VIR_UUID_DEBUG(conn, uuid);
 
     virResetLastError();
 
@@ -9279,7 +9289,7 @@ virStoragePoolLookupByUUIDString(virConnectPtr conn,
                                  const char *uuidstr)
 {
     unsigned char uuid[VIR_UUID_BUFLEN];
-    VIR_DEBUG("conn=%p, uuidstr=%s", conn, uuidstr);
+    VIR_DEBUG("conn=%p, uuidstr=%s", conn, NULLSTR(uuidstr));
 
     virResetLastError();
 
@@ -11766,7 +11776,7 @@ error:
 virSecretPtr
 virSecretLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
 {
-    VIR_DEBUG("conn=%p, uuid=%s", conn, uuid);
+    VIR_UUID_DEBUG(conn, uuid);
 
     virResetLastError();
 
@@ -11811,7 +11821,7 @@ virSecretPtr
 virSecretLookupByUUIDString(virConnectPtr conn, const char *uuidstr)
 {
     unsigned char uuid[VIR_UUID_BUFLEN];
-    VIR_DEBUG("conn=%p, uuidstr=%s", conn, uuidstr);
+    VIR_DEBUG("conn=%p, uuidstr=%s", conn, NULLSTR(uuidstr));
 
     virResetLastError();
 
@@ -13422,7 +13432,7 @@ error:
 virNWFilterPtr
 virNWFilterLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
 {
-    VIR_DEBUG("conn=%p, uuid=%s", conn, uuid);
+    VIR_UUID_DEBUG(conn, uuid);
 
     virResetLastError();
 
@@ -13465,7 +13475,7 @@ virNWFilterPtr
 virNWFilterLookupByUUIDString(virConnectPtr conn, const char *uuidstr)
 {
     unsigned char uuid[VIR_UUID_BUFLEN];
-    VIR_DEBUG("conn=%p, uuidstr=%s", conn, uuidstr);
+    VIR_DEBUG("conn=%p, uuidstr=%s", conn, NULLSTR(uuidstr));
 
     virResetLastError();