Check if we're on the wp-login page?

Question

How can I check if the current page is wp-login.php or wp-signup.php ?

Are there more elegant solutions than using $_SERVER['REQUEST_URI'] ?

Answer 1

Use the global $pagenow;

if ( in_array( $GLOBALS['pagenow'], array( 'wp-login.php', 'wp-register.php' ) ) )
    run_my_funky_plugin();