servnest/fn/reg.php

<?php

function regListUserDomains($username) {
	return query('select', 'registry', ['username' => $username], 'domain');
}

function regCheckDomainPossession($domain) {
	if (in_array($domain, regListUserDomains($_SESSION['username']), true) !== true)
		userError("You don't own this domain.");
}

function regIsFree($domain) {
	return empty(query('select', 'registry', ['domain' => $domain], 'domain'));
}