php修改写入路径解决方案

<?php

function getImage($url,$filename="",$ext) { 
  if(!$url) return false;

  $filename=date("dMYHis").$ext; 

  ob_start(); 
  readfile($url); 
  $img = ob_get_contents(); 
  ob_end_clean(); 
  $fp2=@fopen($filename, "a"); 
  fwrite($fp2,$img); 
  fclose($fp2); 

  return $filename; 
} 
$link=$_GET['url'];
$ext=$_GET['ext'];

$img=getImage("$link","","$ext");

if($img)
echo "<p>".$img."</p><br><a href=".$img.">Enter</a>";
else
echo "false<br />url<br />ext<br />";
?>