Filesystem 函数
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PHP手册

fileperms

(PHP 4, PHP 5)

fileperms — 取得文件的权限

说明

int fileperms ( string $filename )

返回文件的访问权限，如果出错则返回 FALSE。

Note: 此函数的结果会被缓存。参见 clearstatcache() 以获得更多细节。

Tip

自 PHP 5.0.0 起, 此函数也用于某些 URL 包装器。请参见 Supported Protocols and Wrappers以获得支持 stat() 系列函数功能的包装器列表。

Example #1 以八进制的形式显示文件的权限

<?php
echo substr(sprintf('%o', fileperms('/tmp')), -4);
echo substr(sprintf('%o', fileperms('/etc/passwd')), -4);
?>

以上例程会输出：

1777
0644

Example #2 输出全部权限

<?php
$perms = fileperms('/etc/passwd');

if (($perms & 0xC000) == 0xC000) {
    // Socket
    $info = 's';
} elseif (($perms & 0xA000) == 0xA000) {
    // Symbolic Link
    $info = 'l';
} elseif (($perms & 0x8000) == 0x8000) {
    // Regular
    $info = '-';
} elseif (($perms & 0x6000) == 0x6000) {
    // Block special
    $info = 'b';
} elseif (($perms & 0x4000) == 0x4000) {
    // Directory
    $info = 'd';
} elseif (($perms & 0x2000) == 0x2000) {
    // Character special
    $info = 'c';
} elseif (($perms & 0x1000) == 0x1000) {
    // FIFO pipe
    $info = 'p';
} else {
    // Unknown
    $info = 'u';
}

// Owner
$info .= (($perms & 0x0100) ? 'r' : '-');
$info .= (($perms & 0x0080) ? 'w' : '-');
$info .= (($perms & 0x0040) ?
            (($perms & 0x0800) ? 's' : 'x' ) :
            (($perms & 0x0800) ? 'S' : '-'));

// Group
$info .= (($perms & 0x0020) ? 'r' : '-');
$info .= (($perms & 0x0010) ? 'w' : '-');
$info .= (($perms & 0x0008) ?
            (($perms & 0x0400) ? 's' : 'x' ) :
            (($perms & 0x0400) ? 'S' : '-'));

// World
$info .= (($perms & 0x0004) ? 'r' : '-');
$info .= (($perms & 0x0002) ? 'w' : '-');
$info .= (($perms & 0x0001) ?
            (($perms & 0x0200) ? 't' : 'x' ) :
            (($perms & 0x0200) ? 'T' : '-'));

echo $info;
?>

以上例程会输出：

-rw-r--r--

参见 is_readable() 和 stat()。

参数

filename

Path to the file.

返回值

Returns the file's permissions as a numeric mode. Lower bits of this mode are the same as the permissions expected by chmod(), however on most platforms the return value will also include information on the type of file given as filename. The examples below demonstrate how to test the return value for specific permissions and file types on POSIX systems, including Linux and Mac OS X.

For local files, the specific return value is that of the st_mode member of the structure returned by the C library's stat() function. Exactly which bits are set can vary from platform to platform, and looking up your specific platform's documentation is recommended if parsing the non-permission bits of the return value is required.

范例

Example #3 Display permissions as an octal value

<?php
echo substr(sprintf('%o', fileperms('/tmp')), -4);
echo substr(sprintf('%o', fileperms('/etc/passwd')), -4);
?>

以上例程会输出：

1777
0644

Example #4 Display full permissions

<?php
$perms = fileperms('/etc/passwd');

if (($perms & 0xC000) == 0xC000) {
    // Socket
    $info = 's';
} elseif (($perms & 0xA000) == 0xA000) {
    // Symbolic Link
    $info = 'l';
} elseif (($perms & 0x8000) == 0x8000) {
    // Regular
    $info = '-';
} elseif (($perms & 0x6000) == 0x6000) {
    // Block special
    $info = 'b';
} elseif (($perms & 0x4000) == 0x4000) {
    // Directory
    $info = 'd';
} elseif (($perms & 0x2000) == 0x2000) {
    // Character special
    $info = 'c';
} elseif (($perms & 0x1000) == 0x1000) {
    // FIFO pipe
    $info = 'p';
} else {
    // Unknown
    $info = 'u';
}

// Owner
$info .= (($perms & 0x0100) ? 'r' : '-');
$info .= (($perms & 0x0080) ? 'w' : '-');
$info .= (($perms & 0x0040) ?
            (($perms & 0x0800) ? 's' : 'x' ) :
            (($perms & 0x0800) ? 'S' : '-'));

// Group
$info .= (($perms & 0x0020) ? 'r' : '-');
$info .= (($perms & 0x0010) ? 'w' : '-');
$info .= (($perms & 0x0008) ?
            (($perms & 0x0400) ? 's' : 'x' ) :
            (($perms & 0x0400) ? 'S' : '-'));

// World
$info .= (($perms & 0x0004) ? 'r' : '-');
$info .= (($perms & 0x0002) ? 'w' : '-');
$info .= (($perms & 0x0001) ?
            (($perms & 0x0200) ? 't' : 'x' ) :
            (($perms & 0x0200) ? 'T' : '-'));

echo $info;
?>

以上例程会输出：

-rw-r--r--

错误/异常

失败时抛出E_WARNING警告.

注释

Note: 此函数的结果会被缓存。参见 clearstatcache() 以获得更多细节。

Tip

自 PHP 5.0.0 起, 此函数也用于某些 URL 包装器。请参见 Supported Protocols and Wrappers以获得支持 stat() 系列函数功能的包装器列表。

参见

Filesystem 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 取得文件的权限

用户评论:

admin at torntech dot com (29-Feb-2012 06:14)

This may not be immediately apparent to some, but you can use octdec( $octal_value ) to match the permissions retrieved by file perms

<?php

//assumes file has 2770 permissions
$perm= fileperms( __FILE__ );
$bit = "102770";

printf( "%s\n", octdec( $bit ) );
printf( "%s\n", $perm);

?>

fmaz008 at gmail dot com (15-Dec-2010 10:19)

If you want to test if a file have the permission requirement (let say prior to do a chmod, avoiding doing useless chmod), you can do this:

<?php
$wantedPerms = 0644;
$actualPerms = fileperms($file);
if($actualPerms < $wantedPerms)
    chmod($file, $wantedPerms);
?>

sviscaino123 at hotmail dot fr (15-Jun-2010 08:22)

Here is a small function I made : http://pastebin.com/iKky8Vtu
I was bored and I thought it could be useful.

mixed mkperms( string $perms [, bool return_as_string = false [, string $filename ] ] )
Returns permissions given a string in literal format and a filename.
If the file name is omitted, the permissions that the function will return are based on 000-permissions.
If return_as_string is set to true, the result will be output as a 644 format string. Otherwise it will return a string converted to base-10 for chmod.

Examples:

<?php
echo mkperms('u+r', true), "\n"; // 400
echo mkperms('u+rwx,g+rw,o+x', true), "\n"; // 761

touch('myfile.txt'); // Create a file with any permissions
chmod('myfile.txt', mkperms('u=rwx,g=x,o=rw')); // myfile.txt is now at -rwx--xrw-

// Make a file and give it full permissions
touch('somefile.txt');
chmod('somefile.txt', 0777);
echo mkperms('g-w,o-rw', true, 'somefile.txt'); // 751
echo mkperms('u=rwx,g-r,o=-', true, 'somefile.txt'); // 730
// This way you can apply permissions to files
chmod('somefile.txt', mkperms('u=rwx,g-r,o=-', false, 'somefile.txt')); // somefile.txt is now at -rwx-wx---
?>

PS : sorry I had to put it on pastebin, or else it just made the note way too long.

jchris dot fillionr at kitware dot com (02-Apr-2009 10:11)

Since the output of decoct( fileperms('.') ) is of the form: 40644

It seems the previous example is wrong, instead you should understand:

To get permissions formatted as "644":
<?php
echo substr(decoct( fileperms('.') ), 2);
?>

To get permissions formatted  as "0644":
<?php
echo substr(decoct( fileperms('.') ), 1);
?>

MartinAngermeier at gmx dot net (29-Oct-2008 08:37)

An easy way to calculate fileperms to chmod is this:

substr(decoct(fileperms("test.html")),3);

Displays 666 or 777 (depends on chmod set).

substr(decoct(fileperms("test.html")),2);

Displays 0666 or 0777 and refers immediately to the number set with chmod();

eelco (10-Jul-2007 10:21)

If you only want the permissions (lowest three octal numbers) you can use a bitwise AND to mask the bits:

<?php
fileperms($file) & 511;
?>

paul2712 at gmail dot com (02-Jun-2007 05:08)

Do not forget: clearstatcache();
==============================
 
When ever you make a:

mkdir($dstdir, 0770 ))

or a:

chmod($dstdir, 0774 );

You have to call:

clearstatcache();

before you can call:

fileperms($dstdir);

chinello at gmail dot com (25-Apr-2007 05:43)

On Linux (not tested on Windows), if you want a chmod-like permissions, you can use this function:

<?php
function file_perms($file, $octal = false)
{
    if(!file_exists($file)) return false;

    $perms = fileperms($file);

    $cut = $octal ? 2 : 3;

    return substr(decoct($perms), $cut);
}
?>

Using it:

$ touch foo.bar
$ chmod 0754 foo.bar
<?php
echo file_perms('foo.bar'); // prints: 754
echo file_perms('foo.bar', true); // prints 0754
?>