Function sysctl_rules

freebsd/security/mac_portacl/mac_portacl.c:331–373

* Note: due to races, there is not a single serializable order * between parallel calls to the sysctl. */

 * between parallel calls to the sysctl.
 */
static int
sysctl_rules(SYSCTL_HANDLER_ARGS)
{
	char *string, *copy_string, *new_string;
	struct rulehead head, save_head;
	int error;

	new_string = NULL;
	if (req->newptr != NULL) {
		new_string = malloc(MAC_RULE_STRING_LEN, M_PORTACL,
		    M_WAITOK | M_ZERO);
		mtx_lock(&rule_mtx);
		strcpy(new_string, rule_string);
		mtx_unlock(&rule_mtx);
		string = new_string;
	} else
		string = rule_string;

	error = sysctl_handle_string(oidp, string, MAC_RULE_STRING_LEN, req);
	if (error)
		goto out;

	if (req->newptr != NULL) {
		copy_string = strdup(string, M_PORTACL);
		TAILQ_INIT(&head);
		error = parse_rules(copy_string, &head);
		free(copy_string, M_PORTACL);
		if (error)
			goto out;

		TAILQ_INIT(&save_head);
		mtx_lock(&rule_mtx);
		TAILQ_CONCAT(&save_head, &rule_head, r_entries);
		TAILQ_CONCAT(&rule_head, &head, r_entries);
		strcpy(rule_string, string);
		mtx_unlock(&rule_mtx);
		toast_rules(&save_head);
	}
out:
	if (new_string != NULL)
		free(new_string, M_PORTACL);
	return (error);
}

SYSCTL_PROC(_security_mac_portacl, OID_AUTO, rules,
    CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,