int security_getenforce(void);
int security_setenforce(int value);
int security_deny_unknown(void);
security_setenforce sets SELinux to enforcing mode if the value 1 is passed in, and sets it to permissive mode if 0 is passed in. On success 0 is returned, on error -1 is returned.
security_deny_unknown returns 0 if SELinux treats policy queries on undefined object classes or permissions as being allowed, 1 if such queries are denied, and -1 on error.