mid_registrar: Fix mishandled corner-cases

    * avoid extraneous "udomain unlock" operations on some error cases

(cherry picked from commit b3bdf7c)
(cherry picked from commit e3d7b59)

modules/mid_registrar/save.c

@@ -2283,7 +2283,7 @@ int mid_reg_save(struct sip_msg *msg, char *dom, char *flags_gp,
 	str flags_str = { NULL, 0 }, to_uri = { NULL, 0 };
 	struct save_ctx sctx;
 	struct hdr_field *path;
-	int rc = -1, st;
+	int rc = -1, st, unlock_udomain = 0;
 
 	if (msg->REQ_METHOD != METHOD_REGISTER) {
 		LM_ERR("ignoring non-REGISTER SIP request (%d)\n", msg->REQ_METHOD);
@@ -2356,6 +2356,7 @@ int mid_reg_save(struct sip_msg *msg, char *dom, char *flags_gp,
 		return prepare_forward(msg, ud, &sctx);
 
 	update_act_time();
+	unlock_udomain = 1;
 	ul_api.lock_udomain(ud, &sctx.aor);
 
 	if (ul_api.get_urecord(ud, &sctx.aor, &rec) != 0) {
@@ -2380,8 +2381,8 @@ int mid_reg_save(struct sip_msg *msg, char *dom, char *flags_gp,
 	if (rec != NULL && rec->contacts != NULL)
 		build_contact(rec->contacts, msg);
 
-	/* no contacts need updating on the far end registrar */
-	ul_api.unlock_udomain(ud, &sctx.aor);
+	if (unlock_udomain)
+		ul_api.unlock_udomain(ud, &sctx.aor);
 
 	/* quick SIP reply */
 	if (!(sctx.flags & REG_SAVE_NOREPLY_FLAG))
@@ -2394,7 +2395,8 @@ int mid_reg_save(struct sip_msg *msg, char *dom, char *flags_gp,
 	return prepare_forward(msg, ud, &sctx);
 
 out_error:
-	ul_api.unlock_udomain(ud, &sctx.aor);
+	if (unlock_udomain)
+		ul_api.unlock_udomain(ud, &sctx.aor);
 	if (!(sctx.flags & REG_SAVE_NOREPLY_FLAG))
 		send_reply(msg, sctx.flags);
 	return -1;