php检测图片木马

<?php   

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