!$env->is_logged_in&&// And the user isn't logged in
!in_array($_GET["action"],["login","checklogin","opensearch-description","invindex-rebuild","stats-update"]))// And the user isn't trying to login, or get the opensearch description, or access actions that apply their own access rules
exit(page_renderer::render("Login required - $settings->sitename","<p>$settings->sitename requires that you login before you are able to access it.</p>