php检测图片木马

    <?php   
    /** 
      +------------------------------------------------------------------------------ 
    * Upload 文件上传类 
      +------------------------------------------------------------------------------ 
    * @package   Upload 
    * @author    nicegy  
    * @version   $Id: Upload.class.php 2014-4-11 19:00:23 nicegy $ 
      +------------------------------------------------------------------------------ 
    */  
    class Upload {  
       
          private static $image = null;  
          private static $status = 0;  
          private static $suffix = null;  
          private static $imageType = array('.jpg', '.bmp','.gif','.png');  
          private static $message = array(  
                '0' => '没有错误发生，文件上传成功。',  
                '1' => '上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值。',  
                '2' => '上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值。',  
                '3' => '文件只有部分被上传。',  
                '4' => '没有文件上传。',  
                '5' => '未能通过安全检查的文件。',  
                '6' => '找不到临时文件夹。',  
                '7' => '文件写入失败。',  
                '8' => '文件类型不支持',  
                '9' => '上传的临时文件丢失。',  
          );  
       
          //@ 开始执行文件上传  
          public static function start($feild = 'file') {  
                if (!empty($_FILES)) {  
                    self::$status = $_FILES[$feild]['error'];  
                   if (self::$status > 0)  
                          return array('status' => self::$status, 'msg' => self::$message[self::$status]);  
                      self::$image = $_FILES[$feild]['tmp_name'];  
                      self::$suffix = strtolower(strrchr($_FILES[$feild]['name'], '.'));  
                      return array('status' => self::_upload(), 'path' => self::$image, 'msg' => self::$message[self::$status]);  
               } else {  
                      return array('status' => self::$status, 'msg' => self::$message[self::$status]);  
               }  
    }  
       
        //@ 私有 上传开始  
        private static function _upload($path = './upload/') {  
            date_default_timezone_set('PRC');  
            $newFile = $path . date('Y/m/d/His') . rand(100, 999) . self::$suffix;  
            self::umkdir(dirname($newFile));  
            if (is_uploaded_file(self::$image) && move_uploaded_file(self::$image, $newFile)) {  
                self::$image = $newFile;  
                if (in_array(self::$suffix, self::$imageType))  
                    return self::checkHex();  
                else  
                    return self::$status = 0;  
            } else {  
                return self::$status = 9;  
            }  
        }  
       
        //@ 私有 16进制检测 黑客  
        private static function checkHex() {  
            if (file_exists(self::$image)) {  
                $resource = fopen(self::$image, 'rb');  
                $fileSize = filesize(self::$image);  
                fseek($resource, 0);  
                if ($fileSize > 512) { // 取头和尾  
                    $hexCode = bin2hex(fread($resource, 512));  
                    fseek($resource, $fileSize - 512);  
                    $hexCode .= bin2hex(fread($resource, 512));  
                } else { // 取全部  
                    $hexCode = bin2hex(fread($resource, $fileSize));  
                }  
                fclose($resource);  
                /* 匹配16进制中的 */  
                /* 匹配16进制中的 */  
                /* 匹配16进制中的