function siteaccess_register_hook($hook, $entity_type, $returnvalue, $params)
{
    $error = false;
    if (siteaccess_invitecode_enabled()) {
        $friend_guid = get_input('friend_guid');
        $invitecode = get_input('invitecode');
        if ($friend_guid) {
            if ($friend_user = get_user($friend_guid)) {
                if (!$invitecode == generate_invite_code($friend_user->username)) {
                    $error = true;
                }
            } else {
                $error = true;
            }
        } else {
            $error = true;
        }
    }
    if ($error) {
        register_error(elgg_echo('siteaccess:invitecode:invalid'));
    }
    if (siteaccess_key_enabled()) {
        $sitekey = get_plugin_setting('siteaccesskey', 'siteaccess');
        $inputkey = get_input('siteaccesskey');
        if (trim($inputkey) == "" || strcmp($inputkey, $sitekey) != 0) {
            register_error(elgg_echo('siteaccess:key:invalid'));
            $error = true;
        }
    }
    if (siteaccess_coppa_enabled()) {
        $coppa = get_input('coppa');
        if (!$coppa) {
            register_error(elgg_echo('siteaccess:coppa:fail'));
            $error = true;
        }
    }
    if (extension_loaded("gd")) {
        if (!siteaccess_validate_captcha()) {
            $error = true;
        }
    }
    if ($error) {
        siteaccess_register_fail();
    }
}
<?php

$username = get_input('u');
$email = get_input('e');
$name = get_input('n');
$admin_option = false;
if ($_SESSION['user']->admin && $vars['show_admin']) {
    $admin_option = true;
}
$form_body = "<p><label>" . "Full Name" . "<br />" . elgg_view('input/text', array('internalname' => 'name', 'class' => "general-textarea", 'value' => $name)) . "</label><br />";
$form_body .= "<label>" . elgg_echo('email') . "<br />" . elgg_view('input/text', array('internalname' => 'email', 'class' => "general-textarea", 'value' => $email)) . "</label><br />";
$form_body .= "<label>" . elgg_echo('username') . "<br />" . elgg_view('input/text', array('internalname' => 'username', 'class' => "general-textarea", 'value' => $username)) . "</label><br />";
$form_body .= "<label>" . elgg_echo('password') . "<br />" . elgg_view('input/password', array('internalname' => 'password', 'class' => "general-textarea")) . "</label><br />";
$form_body .= "<label>" . elgg_echo('passwordagain') . "<br />" . elgg_view('input/password', array('internalname' => 'password2', 'class' => "general-textarea")) . "</label><br />";
$form_body .= elgg_view('siteaccess/register');
if (siteaccess_key_enabled()) {
    $form_body .= "<label>" . elgg_echo('siteaccess:key:enter') . "<br />" . elgg_view('input/password', array('internalname' => 'siteaccesskey', 'value' => $siteaccesskey, 'class' => "general-textarea")) . "</label><br />";
}
if (siteaccess_coppa_enabled()) {
    $form_body .= "<label><br />" . elgg_view('input/checkboxes', array('internalname' => 'coppa', 'options' => array(elgg_echo('siteaccess:coppa:text')), 'value' => 'coppa', 'class' => "general-textarea")) . "</label><br />";
}
if ($admin_option) {
    $form_body .= elgg_view('input/checkboxes', array('internalname' => "admin", 'options' => array(elgg_echo('admin_option'))));
}
//	if (extension_loaded("gd"))
$form_body .= elgg_view('siteaccess/code');
//		$form_body .= elgg_view('input/captcha');
$form_body .= elgg_view('input/hidden', array('internalname' => 'friend_guid', 'value' => $vars['friend_guid']));
$form_body .= elgg_view('input/hidden', array('internalname' => 'invitecode', 'value' => $vars['invitecode']));
$form_body .= elgg_view('input/hidden', array('internalname' => 'action', 'value' => 'register'));
$form_body .= elgg_view('input/submit', array('internalname' => 'submit', 'value' => elgg_echo('register'))) . "</p>";