attr_get(1.说明 2.参数 3.返回值)

实例讲解

attr_get

xattr_get -- Get an extended attribute(得到一个扩展属性)

1.说明

string xattr_get( string filename, string name [, int flags] )

This function gets the value of an extended attribute of a file.

扩展的属性有两个不同的名字空间：user 和 root 名字空间。user 名字空间对所有用户均有效，而 root 名字空间仅对拥有 root 权限的用户有效。xattr 默认在 user 名字空间上进行操作，但是可以使用 flags参数进行更改。

2.参数

filename

The file from which we get the attribute.

name The name of the attribute.

flags:

XATTR_DONTFOLLOW　Do not follow the symbolic link but operate on symbolic link itself.

XATTR_ROOT　Set attribute in root (trusted) namespace. Requires root privileges.

3.返回值

Returns a string containing the value or FALSEif the attribute doesn't exist.

实例讲解

]Checks if system administrator has signed the fileb]　<?php

$file = '/usr/local/sbin/some_binary';

$signature = xattr_get($file, 'Root signature', XATTR_ROOT);

/* ... check if $signature is valid ... */

?>