xattr_get
(PECL xattr >= 0.9.0)
xattr_get — Get an extended attribute
说明
This function gets the value of an extended attribute of a file.
扩展的属性有两种 不同的命名空间:user
和 root。user 命名空间对所有用户均有效,而 root
命名空间仅对拥有 root 权限的用户有效。
xattr 默认在 user 命名空间上操作,但可使用
flags
参数进行更改。
参数
filename
-
The file from which we get the attribute.
name
-
The name of the attribute.
flags
-
Supported xattr 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.
返回值
Returns a string containing the value or false
if the attribute doesn't
exist.
示例
示例 #1 Checks if system administrator has signed the file
<?php
$file = '/usr/local/sbin/some_binary';
$signature = xattr_get($file, 'Root signature', XATTR_ROOT);
/* ... check if $signature is valid ... */
?>
参见
- xattr_list() - Get a list of extended attributes
- xattr_set() - Set an extended attribute
- xattr_remove() - Remove an extended attribute
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