php fil som listar innehåll i en mapp

<?php
$sokvag = "c:/";
$mapp = opendir($sokvag);
while ($namn = readdir($mapp))
    echo "$namn<br>\n";
?>

<form method="post">
Mapp: <input type="text" name="mapp" value="<?php echo $_POST["mapp"]; ?>"><br>
Sök: <input type="text" name="fil" value="<?php echo $_POST["fil"]; ?>"><br>
<input type="submit" name="sok" value="Söööök!">
</form>
<?php
	$mapp = $_POST["mapp"];
	$sok = $_POST["fil"];
	if (!isset($_POST["sok"])) die();
	$filer = "";

	function mapp($dir)
	{
		global $filer;
		global $sok;
		$katalog = opendir($dir);
		while ($fil = readdir($katalog))
		{
			if ($fil == "." || $fil == "..") continue;

			if (is_dir($dir."/".$fil))
				mapp($dir."/".$fil);
			if (strstr($fil, $sok))
			{
				$filer[] = $fil;
			}
		}
	}

	mapp($mapp);

	if (is_array($filer))
	foreach ($filer as $fil)
	{
		echo "$fil<br>";
	}
	else
		echo "Hittade inga filer";
?>