+static int check_good_user(sd_bus_message *m, uid_t good_user) {
+ _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+ uid_t sender_uid;
+ int r;
+
+ assert(m);
+
+ if (good_user == UID_INVALID)
+ return 0;
+
+ r = sd_bus_query_sender_creds(m, SD_BUS_CREDS_EUID, &creds);
+ if (r < 0)
+ return r;
+
+ r = sd_bus_creds_get_euid(creds, &sender_uid);
+ if (r < 0)
+ return r;
+
+ return sender_uid == good_user;
+}
+