Custom Login & Shortcodes: add custom login stylesheet, change logo link and link URL. Snippet for functions.php, use with style-login.css

functions.php

<?php

/* Shortcodes in Widget text & titles */
add_filter( 'widget_text', 'shortcode_unautop');
add_filter( 'widget_text', 'do_shortcode');
add_filter( 'widget_title', 'shortcode_unautop');
add_filter( 'widget_title', 'do_shortcode');

/* Additional Shortcodes */
add_shortcode('url','url_shortcode');
add_shortcode('template-url', 'template_shortcode');
add_shortcode('stylesheet-directory', 'stylesheet_shortcode');
add_shortcode('site-name', 'sitename_shortcode');

function url_shortcode($atts) {
return get_bloginfo('url');
}

function template_shortcode($atts) {
return get_bloginfo('template_url');
}

function stylesheet_shortcode($atts) {
return get_bloginfo('stylesheet_directory');
}

function sitename_shortcode($atts) {
  return get_bloginfo('name');
}

// Custom login
// http://codex.wordpress.org/Customizing_the_Login_Form#Change_the_Login_Logo

function sw_login_stylesheet() {
    wp_enqueue_style( 'custom-login', get_stylesheet_directory_uri() . '/style-login.css' );
}
add_action( 'login_enqueue_scripts', 'sw_login_stylesheet' );

function sw_login_logo_url() {
    return get_bloginfo( 'url' );
}
add_filter( 'login_headerurl', 'sw_login_logo_url' );

function sw_login_logo_url_title() {
    // return 'Site Name';
    // return 'echo do_shortcode( '[site-name]' )';
    return get_bloginfo('name');
}
add_filter( 'login_headertitle', 'sw_login_logo_url_title' );