+static inline bool filter_check_loop(filter_t *filter, A(filter_t) *array, bool cleanup)
+{
+ if (cleanup) {
+ foreach (filter_t *filter2, *array) {
+ filter2->seen = false;
+ }}
+ } else if (filter->seen) {
+ return false;
+ }
+ if (filter->safe) {
+ return true;
+ }
+ filter->seen = true;
+ foreach (filter_hook_t *hook, filter->hooks) {
+ if (hook->postfix) {
+ continue;
+ }
+ if (!filter_check_loop(array_ptr(*array, hook->filter_id), array, false)) {
+ return false;
+ }
+ }}
+ filter->safe = true;
+ return true;
+}
+
+bool filter_check_safety(A(filter_t) *array)
+{
+ foreach (filter_t *filter, *array) {
+ if (!filter_check_loop(filter, array, true)) {
+ syslog(LOG_ERR, "the filter tree contains a loop");
+ return false;
+ }
+ }}
+ return true;
+}
+