root/tags/1_0-rc1/wpmu-settings.php

<?php
if( defined( 'ABSPATH' ) == false )
    die();

$wpmuBaseTablePrefix = $table_prefix;

$domain = addslashes( $_SERVER['HTTP_HOST'] );
if( substr( $domain, 0, 4 ) == 'www.' )
    $domain = substr( $domain, 4 );
$domain = preg_replace('/:.*$/', '', $domain); // Strip ports

$path = preg_replace( '|([a-z0-9-]+.php.*)|', '', $_SERVER['REQUEST_URI'] );
$path = str_replace ( '/wp-admin/', '/', $path );
$path = preg_replace( '|(/[a-z0-9-]+?/).*|', '$1', $path );

$wpdb->hide_errors();

#$sites = $wpdb->get_results( "SELECT * FROM $wpdb->site" );
#if( count( $sites ) == 1 ) {
    #$current_site = $sites[0];
#}
    
if( isset( $current_site ) == false ) {
    $path = substr( $_SERVER[ 'REQUEST_URI' ], 0, 1 + strpos( $_SERVER[ 'REQUEST_URI' ], '/', 1 ) );
    if( constant( 'VHOST' ) == 'yes' ) {
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='$path'" );
        if( $current_site == null ) {
            $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='/'" );
            if( $current_site == null ) {
                $sitedomain = substr( $domain, 1 + strpos( $domain, '.' ) );
                $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$sitedomain' AND path='$path'" );
                if( $current_site == null ) {
                    $path = '/';
                    $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$sitedomain' AND path='$path'" );
                    if( $current_site == null && defined( "WP_INSTALLING" ) == false )
                        die( "No WPMU site defined on this host." );
                }
            } else {
                $path = '/';
            }
        }
    } else {
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='$path'" );
        if( $current_site == null ) {
            $path = '/';
            $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='$path'" );
            if( $current_site == null && defined( "WP_INSTALLING" ) == false )
                die( "No WPMU site defined on this host." );
        }
    }
}


if( constant( 'VHOST' ) == 'yes' ) {
    $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain'");
    if( $current_blog != null )
        $current_site = $wpdb->get_row("SELECT * FROM $wpdb->site WHERE id='{$current_blog->site_id}'");
} else {
    $blogname = htmlspecialchars( substr( $_SERVER[ 'REQUEST_URI' ], strlen( $path ) ) );
    if( strpos( $blogname, '/' ) )
        $blogname = substr( $blogname, 0, strpos( $blogname, '/' ) );
    if( $blogname == '' || $blogname == 'blog' || $blogname == 'wp-admin' || $blogname == 'files' || $blogname == 'feed' || is_file( $blogname ) ) {
        $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain' AND path = '$path'");
    } else {
        $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain' AND path = '{$path}{$blogname}/'");
    }
}

if( defined( "WP_INSTALLING" ) == false ) {
    if( $current_blog == false || $current_site == false )
        is_installed();
}

$blog_id = $current_blog->blog_id;
$public  = $current_blog->public;
$site_id = $current_blog->site_id;

if( $site_id == 0 )
    $site_id = 1;

$current_site->site_name = $wpdb->get_var( "SELECT meta_value FROM $wpdb->sitemeta WHERE site_id = '$site_id' AND meta_key = 'site_name'" );
if( $current_site->site_name == null )
    $current_site->site_name = ucfirst( $current_site->domain );

if( $blog_id == false ) {
    // no blog found, are we installing? Check if the table exists.
    if ( defined('WP_INSTALLING') ) {
    $query = "SELECT blog_id FROM ".$wpdb->blogs." limit 0,1";
    $blog_id = $wpdb->get_var( $query );
    if( $blog_id == false ) {
        // table doesn't exist. This is the first blog
        $blog_id = 1;
    } else {
        // table exists
        // don't create record at this stage. we're obviously installing so it doesn't matter what the table vars below are like.
        // default to using the "main" blog.
        $blog_id = 1;
    }
    } else {
    $check = $wpdb->get_results( "SELECT * FROM $wpdb->site" );
    if( $check == false ) {
        $msg = ': DB Tables Missing';
    } else {
        $msg = '';
    }
    die( "No Blog by that name on this system." . $msg );
    }
}

$wpdb->show_errors();

if( '0' == $current_blog->public ) {
    // This just means the blog shouldn't show up in google, etc. Only to registered members
}

if( $current_blog->archived == '1' ) {
    die( 'This blog has been archived or suspended.' );
}

if( $current_blog->spam == '1' ) {
    die( 'This blog has been archived or suspended.' );
}

function is_installed() {
    global $wpdb, $domain, $path;
    $base = stripslashes( $base );
    if( defined( "WP_INSTALLING" ) == false ) {
        $check = $wpdb->get_results( "SELECT * FROM $wpdb->site" );
        if( $check == false ) {
            $msg = '<strong>Database Tables Missing.</strong><br /> The table <em>' . DB_NAME . '::' . $wpdb->site . '</em> is missing. Delete the .htaccess file and run the installer again!<br />';
        } else {
            $msg = '<strong>Could Not Find Blog!</strong><br />';
            $msg .= "Searched for <em>" . $domain . $path . "</em> in " . DB_NAME . "::" . $wpdb->blogs . " table. Is that right?<br />";
        }
        $msg .= "Please check that your database contains the following tables:<ul>
            <li> $wpdb->blogs </li>
            <li> $wpdb->users </li>
            <li> $wpdb->usermeta </li>
            <li> $wpdb->site </li>
            <li> $wpdb->sitemeta </li>
            <li> $wpdb->sitecategories </li>
            </ul>";
        $msg .= "If you suspect a problem please report it to <a href='http://mu.wordpress.org/forums/'>support forums</a>!";
        die( "<h1>Fatal Error</h1> " . $msg );
    }
}

$table_prefix = $table_prefix . $blog_id . '_';

?>