- prefix = strndupa(opts, start - opts - (start != opts));
- postfix = timeout + len + (timeout[len] != '\0');
- *filtered = strjoin(prefix, *postfix ? postfix : NULL, NULL);
- if (!*filtered)
- return log_oom();
+ if (filtered) {
+ char *prefix, *postfix;
+
+ prefix = strndupa(opts, start - opts - (start != opts));
+ postfix = timeout + len + (timeout[len] != '\0');
+ *filtered = strjoin(prefix, *postfix ? postfix : NULL, NULL);
+ if (!*filtered)
+ return log_oom();
+ }