php下载获取远程图片函数(可伪造来路)

<?php 
//下载获取远程图片 
function DownImageKeep($gurl, $rfurl, $filename, $gcookie="", $JumpCount=0, $maxtime=30) 
{ 
    $urlinfos = GetHostInfo($gurl); 
    $ghost = trim($urlinfos['host']); 
    if($ghost=='') 
    { 
        return FALSE; 
    } 
    $gquery = $urlinfos['query']; 
    if($gcookie=="" && !empty($rfurl)) 
    { 
        $gcookie = RefurlCookie($rfurl); 
    } 
    $sessionQuery = "GET $gquery HTTP/1.1rn"; 
    $sessionQuery .= "Host: $ghostrn"; 
    $sessionQuery .= "Referer: $rfurlrn"; 
    $sessionQuery .= "Accept: */*rn"; 
    $sessionQuery .= "User-Agent: Mozilla/4.0 (compatible; MSIE 5.00; Windows 98)rn"; 
    if($gcookie!="" && !preg_match("/[rn]/", $gcookie)) 
    { 
        $sessionQuery .= $gcookie."rn"; 
    } 
    $sessionQuery .= "Connection: Keep-Alivernrn"; 
    $errno = ""; 
    $errstr = ""; 
    $m_fp = fsockopen($ghost, 80, $errno, $errstr,10); 
    fwrite($m_fp,$sessionQuery); 
    $lnum = 0; 
 
    //获取详细应答头 
    $m_httphead = Array(); 
    $httpstas = explode(" ",fgets($m_fp,256)); 
    $m_httphead["http-edition"] = trim($httpstas[0]); 
    $m_httphead["http-state"] = trim($httpstas[1]); 
    while(!feof($m_fp)) 
    { 
        $line = trim(fgets($m_fp,256)); 
        if($line == "" || $lnum>100) 
        { 
            break; 
        } 
        $hkey = ""; 
        $hvalue = ""; 
        $v = 0; 
        for($i=0; $i<strlen($line); $i++) 
        { 
            if($v==1) 
            { 
                $hvalue .= $line[$i]; 
            } 
            if($line[$i]==":") 
            { 
                $v = 1; 
            } 
            if($v==0) 
            { 
                $hkey .= $line[$i]; 
            } 
        } 
        $hkey = trim($hkey); 
        if($hkey!="") 
        { 
            $m_httphead[strtolower($hkey)] = trim($hvalue); 
        } 
    } 
 
    //分析返回记录 
    if(preg_match("/^3/", $m_httphead["http-state"])) 
    { 
        if(isset($m_httphead["location"]) && $JumpCount<3) 
        { 
            $JumpCount++; 
            DownImageKeep($gurl,$rfurl,$filename,$gcookie,$JumpCount); 
        } 
        else 
        { 
            return FALSE; 
        } 
    } 
    if(!preg_match("/^2/", $m_httphead["http-state"])) 
    { 
        return FALSE; 
    } 
    if(!isset($m_httphead)) 
    { 
        return FALSE; 
    } 
    $contentLength = $m_httphead['content-length']; 
 
    //保存文件 
    $fp = fopen($filename,"w") or die("写入文件：{$filename} 失败！"); 
    $i=0; 
    $okdata = ""; 
    $starttime = time(); 
    while(!feof($m_fp)) 
    { 
        $okdata .= fgetc($m_fp); 
        $i++; 
 
        //超时结束 
        if(time()-$starttime>$maxtime) 
        { 
            break; 
        } 
 
        //到达指定大小结束 
        if($i >= $contentLength) 
        { 
            break; 
        } 
    } 
    if($okdata!="") 
    { 
        fwrite($fp,$okdata); 
    } 
    fclose($fp); 
    if($okdata=="") 
    { 
        @unlink($filename); 
        fclose($m_fp); 
        return FALSE; 
    } 
    fclose($m_fp); 
    return TRUE; 
} 
 
/** 
 *  获得某页面返回的Cookie信息 
 * 
 * @access    public 
 * @param     string  $gurl  调整地址 
 * @return    string 
 */ 
function RefurlCookie($gurl) 
{ 
    global $gcookie,$lastRfurl; 
    $gurl = trim($gurl); 
    if(!empty($gcookie) && $lastRfurl==$gurl) 
    { 
        return $gcookie; 
    } 
    else 
    { 
        $lastRfurl=$gurl; 
    } 
    if(trim($gurl)=='') 
    { 
        return ''; 
    } 
    $urlinfos = GetHostInfo($gurl); 
    $ghost = $urlinfos['host']; 
    $gquery = $urlinfos['query']; 
    $sessionQuery = "GET $gquery HTTP/1.1rn"; 
    $sessionQuery .= "Host: $ghostrn"; 
    $sessionQuery .= "Accept: */*rn"; 
    $sessionQuery .= "User-Agent: Mozilla/4.0 (compatible; MSIE 5.00; Windows 98)rn"; 
    $sessionQuery .= "Connection: Closernrn"; 
    $errno = ""; 
    $errstr = ""; 
    $m_fp = fsockopen($ghost, 80, $errno, $errstr,10) or die($ghost.'<br />'); 
    fwrite($m_fp,$sessionQuery); 
    $lnum = 0; 
 
    //获取详细应答头 
    $gcookie = ""; 
    while(!feof($m_fp)) 
    { 
        $line = trim(fgets($m_fp,256)); 
        if($line == "" || $lnum>100) 
        { 
            break; 
        } 
        else 
        { 
            if(preg_match("/^cookie/i", $line)) 
            { 
                $gcookie = $line; 
                break; 
            } 
        } 
    } 
    fclose($m_fp); 
    return $gcookie; 
} 
 
/** 
 *  获得网址的host和query部份 
 * 
 * @access    public 
 * @param     string  $gurl  调整地址 
 * @return    string 
 */ 
function GetHostInfo($gurl) 
{ 
    $gurl = preg_replace("/^http:///i", "", trim($gurl)); 
    $garr['host'] = preg_replace("//(.*)$/i", "", $gurl); 
    $garr['query'] = "/".preg_replace("/^([^/]*)//i", "", $gurl); 
    return $garr; 
} 
?>