fgetc() feof() PHP 中的参数错误

Question

今天我收到来自我的 Web 服务器管理员的电子邮件，说"由于大约 60 GB 的错误文件，您的服务已暂停。检查错误日志.txt通过 FTP 检查。在日志文件中，只有以下两行重复：

[Tue Apr 04 08:45:52 2017] [error] [client xxx.xxx.xxx.xxx] PHP Warning:   feof() expects parameter 1 to be resource, boolean given in /var/www/vhosts/.../httpdocs/dene.php on line 11
[Tue Apr 04 08:45:52 2017] [error] [client xxx.xxx.xxx.xxx] PHP Warning:  fgetc() expects parameter 1 to be resource, boolean given in /var/www/vhosts/.../httpdocs/dene.php on line 13

这是相关的代码片段：

<?
header("X-XSS-Protection: 0");
$filename= $_GET['filename'];
$code = $_POST['code'];
if (isset($filename)) 
{
    $go = $filename;
    $full = "docs/$filename.htm";
    $filename = @fopen($full , 'r');
    $file_size = filesize($full);
    while (! feof($filename))  //line 11
    {
        $char = fgetc ($filename); //line13
        $code .= "$char";
    }
    fclose($filename);
}
    $code = str_replace("\", "", $code);
$code = str_replace("&gt;", ">", $code);
$code = str_replace("&#61;", "=", $code);
$code = str_replace("&lt;", "<", $code);
printf("%s",$code);
?>

这里有什么问题？提前感谢...

Answer 1

您需要检查fopen结果。

$resource = @fopen($filename , 'r');
if ( $resource ) {
   while (! feof($resource))
   {
     ...
   }
}

来自 PHP 手册：

<?php
// if file can not be read or doesn't exist fopen function returns  FALSE
$file = @fopen("no_such_file", "r");
// FALSE from fopen will issue warning and result in infinite loop here
while (!feof($file)) {
}
fclose($file);
?>

Answer 2

您

收到这些错误是因为您没有在feof和fgetc中将有效的资源作为参数传递。应确保在以下位置传递有效的文件指针：

$filename = @fopen($full , 'r');

您应该确保：

1. 您尝试打开的文件存在
2. 并且它具有正确的权限。(如果需要，CHMOD 775(

如果上述之一失败，$filename将返回false 。您还可以改进代码逻辑以处理此错误情况，如下所示：

    $filename = @fopen( $full, 'r' );
// Make sure we have a valid file resource
if ( $filename ) {
    $file_size = filesize( $full );
    while ( ! feof( $filename ) )
    {
        $char = fgetc( $filename );
        $code .= "$char";
    }
    fclose( $filename );
} else {
    // Not a valid file resource
    die( "This file resource could not be open." );
}

注意：$filename实际上不是正确的变量名称，则应将其重命名为$filePointer或$fp