Function fail_point_set

freebsd/kern/kern_fail.c:761–860

* Set an internal fail_point structure from a human-readable failpoint string * in a lock-safe manner. */

 * in a lock-safe manner.
 */
static int
fail_point_set(struct fail_point *fp, char *buf)
{
	struct fail_point_entry *ent, *ent_next;
	struct fail_point_setting *entries;
	bool should_wake_paused;
	bool should_truncate;
	int error;

	error = 0;
	should_wake_paused = false;
	should_truncate = false;

	/* Parse new entries. */
	/**
	 * ref protects our new malloc'd stuff from being garbage collected
	 * before we link it.
	 */
	fail_point_setting_get_ref(fp);
	entries = fail_point_setting_new(fp);
	if (parse_fail_point(entries, buf) == NULL) {
		STAILQ_REMOVE(&fp_setting_garbage, entries,
		        fail_point_setting, fs_garbage_link);
		fail_point_setting_destroy(entries);
		error = EINVAL;
		goto end;
	}

	/**
	 * Transfer the entries we are going to keep to a new list.
	 * Get rid of useless zero probability entries, and entries with hit
	 * count 0.
	 * If 'off' is present, and it has no hit count set, then all entries
	 *       after it are discarded since they are unreachable.
	 */
	TAILQ_FOREACH_SAFE(ent, &entries->fp_entry_queue, fe_entries, ent_next) {
		if (ent->fe_prob == 0 || ent->fe_count == 0) {
			printf("Discarding entry which cannot execute %s\n",
			        fail_type_strings[ent->fe_type].name);
			TAILQ_REMOVE(&entries->fp_entry_queue, ent,
			        fe_entries);
			fp_free(ent);
			continue;
		} else if (should_truncate) {
			printf("Discarding unreachable entry %s\n",
			        fail_type_strings[ent->fe_type].name);
			TAILQ_REMOVE(&entries->fp_entry_queue, ent,
			        fe_entries);
			fp_free(ent);
			continue;
		}

		if (ent->fe_type == FAIL_POINT_OFF) {
			should_wake_paused = true;
			if (ent->fe_count == FE_COUNT_UNTRACKED) {
				should_truncate = true;
				TAILQ_REMOVE(&entries->fp_entry_queue, ent,
				        fe_entries);