are-you-licensed.php

<?php

/*
Plugin Name: Are You Licensed?
Description: This plugin checks your hostname to see if you are adhering to the <a href="http://wordpressfoundation.org/trademark-policy/">WordPress Foundation Trademark Policy</a>. It does <strong>not</strong> check if you are running an activated installation of WordPress. This not a Microsoft plugin. 
Author: Jan Dembowski
Author URI: https://blog.dembowski.net/
Version: 0.3
*/

 add_action( 'loop_end' , 'mh_licensed' );
// add_action( 'loop_start' , 'mh_licensed' );

function mh_licensed( $query ) {

	// I want to output the license statement after the main loop and no where else.

	if( $query->is_main_query() ) {

		// This will explode the home_url() into an array along the '.' character
		// and slice the last 3 elements into an array.

		// So if I have a home_url() of "aa.bb.cc.dd.ee.domain.tld/wordpress" then
		// this will rip out the "ee", "domain" and "tld/wordpress" parts only.

		// The array will either have 3 or 2 elements in it.

		$mh_output = array_slice( explode( '.' , home_url() ) , -3 , 3 );

		// If the 2nd level domain contains 'wordpress' then echo that we're bad people

		if ( strpos( strtolower( $mh_output[ count( $mh_output ) - 2 ] ) , 'wordpress' ) ) {

			$mh_message = 'We use "wordpress" in our second level domain which is a contravention ';
			$mh_message .= 'of the <a href="http://wordpressfoundation.org/trademark-policy/" target="_blank">WordPress Foundation Tardemark Policy.</a> ';
			$mh_message .= 'We may not be nice people. You should leave our site and never return.';

			echo '<p style="text-align: center; padding: 10px 20px 10px 20px;">' . $mh_message . '</p>';
			return;
		}

		// If the 3rd level domain contains 'wordpress' then we're compliant and say so.

		if ( strpos( strtolower( $mh_output[ count( $mh_output ) - 3 ] ) , 'wordpress' ) ) {

			$mh_message = 'We use "wordpress" in our subdomain in compliance with ';
			$mh_message .= '<a href="http://wordpressfoundation.org/trademark-policy/" target="_blank">The WordPress Foundation Trademark Policy.</a>';

			echo '<p style="text-align: center; padding: 10px 20px 10px 20px;">' . $mh_message . '</p>';
			return;
		}

		// If the directory contains 'wordpress' then we're compliant and say so.

		if ( strpos( strtolower( $mh_output[  count( $mh_output ) - 1 ] ) , 'wordpress' ) ) {

			$mh_message = 'We use "wordpress" in our subdirectory name in compliance with  ';
			$mh_message .= '<a href="http://wordpressfoundation.org/trademark-policy/" target="_blank">The WordPress Foundation Trademark Policy.</a>';

			echo '<p style="text-align: center; padding: 10px 20px 10px 20px;">' . $mh_message . '</p>';
			return;
		}
	}
}