root/trunk/wp-admin/admin.php

<?php
/**
 * WordPress Administration Bootstrap
 *
 * @package WordPress
 * @subpackage Administration
 */

/**
 * In WordPress Administration Panels
 *
 * @since unknown
 */
define('WP_ADMIN', TRUE);

if ( defined('ABSPATH') )
    require_once(ABSPATH . 'wp-load.php');
else
    require_once('../wp-load.php');

if ( get_option('db_version') != $wp_db_version ) {
    wp_redirect(admin_url('upgrade.php?_wp_http_referer=' . urlencode(stripslashes($_SERVER['REQUEST_URI']))));
    exit;
}

require_once(ABSPATH . 'wp-admin/includes/admin.php');

auth_redirect();

nocache_headers();

update_category_cache();

$posts_per_page = get_option('posts_per_page');
$what_to_show = get_option('what_to_show');
$date_format = get_option('date_format');
$time_format = get_option('time_format');

wp_reset_vars(array('profile', 'redirect', 'redirect_url', 'a', 'popuptitle', 'popupurl', 'text', 'trackback', 'pingback'));

wp_admin_css_color('classic', __('Classic'), admin_url("css/colors-classic.css"), array('#07273E', '#14568A', '#D54E21', '#2683AE'));
wp_admin_css_color('fresh', __('Fresh'), admin_url("css/colors-fresh.css"), array('#464646', '#CEE1EF', '#D54E21', '#2683AE'));

wp_enqueue_script( 'common' );
wp_enqueue_script( 'jquery-color' );

$editing = false;

if (isset($_GET['page'])) {
    $plugin_page = stripslashes($_GET['page']);
    $plugin_page = plugin_basename($plugin_page);
}

require(ABSPATH . 'wp-admin/menu.php');

do_action('admin_init');

// Handle plugin admin pages.
if (isset($plugin_page)) {
    $page_hook = get_plugin_page_hook($plugin_page, $pagenow);

    if ( $page_hook ) {
        do_action('load-' . $page_hook);
        if (! isset($_GET['noheader']))
            require_once(ABSPATH . 'wp-admin/admin-header.php');

        do_action($page_hook);
    } else {
        if ( validate_file($plugin_page) ) {
            wp_die(__('Invalid plugin page'));
        }

        if (! ( file_exists(WP_PLUGIN_DIR . "/$plugin_page") && is_file(WP_PLUGIN_DIR . "/$plugin_page") ) )
            wp_die(sprintf(__('Cannot load %s.'), htmlentities($plugin_page)));

        do_action('load-' . $plugin_page);

        if (! isset($_GET['noheader']))
            require_once(ABSPATH . 'wp-admin/admin-header.php');

        include(WP_PLUGIN_DIR . "/$plugin_page");
    }

    include(ABSPATH . 'wp-admin/admin-footer.php');

    exit();
} else if (isset($_GET['import'])) {

    $importer = $_GET['import'];

    if ( ! current_user_can('import') )
        wp_die(__('You are not allowed to import.'));

    if ( validate_file($importer) ) {
        wp_die(__('Invalid importer.'));
    }

    // Allow plugins to define importers as well
    if (! is_callable($wp_importers[$importer][2]))
    {
        if (! file_exists(ABSPATH . "wp-admin/import/$importer.php"))
        {
            wp_die(__('Cannot load importer.'));
        }
        include(ABSPATH . "wp-admin/import/$importer.php");
    }

    $parent_file = 'users.php';
    $submenu_file = 'import.php';
    $title = __('Import');

    if (! isset($_GET['noheader']))
        require_once(ABSPATH . 'wp-admin/admin-header.php');

    require_once(ABSPATH . 'wp-admin/includes/upgrade.php');

    define('WP_IMPORTING', true);

    call_user_func($wp_importers[$importer][2]);

    include(ABSPATH . 'wp-admin/admin-footer.php');

    exit();
} else {
    do_action("load-$pagenow");
}

if ( !empty($_REQUEST['action']) )
    do_action('admin_action_' . $_REQUEST['action']);

?>