function my_wp() {
$user_id = get_current_user_id();
$class = get_user_meta( $user_id, 'user_class', true );
$role = get_user_meta( $user_id, 'user_role', true );
if ( ( $class != 5 || $role != 'user_role_4' ) && is_single() ) {
global $wp_query;
$wp_query->set_404();
status_header( 404 );
}
}
add_action( 'wp', 'my_wp' );