fileperms()

(PHP 4, PHP 5, PHP 7)

取得文件的权限

说明

fileperms(string $filename): int

取得文件的权限。

参数

$filename: 文件的路径。

返回值

以数字模式返回文件的访问权限。 Returns the file's permissions as a numeric mode. Lower bits of this mode are the same as the permissions expected bychmod(), 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 thest_modemember of the structure returned by the C library'sstat()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

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

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--

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。请参见支持的协议和封装协议以获得支持stat()系列函数功能的包装器列表。

参见

chmod() 改变文件模式
is_readable() 判断给定文件名是否可读
stat() 给出文件的信息

Don't use substr, use bit operator
<?php
decoct(fileperms($file) & 0777); // return "755" for example
?>
If you want to compare permission
<?php
0755 === (fileperms($file) & 0777);
?>

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);
?>

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);

An easy way to calculate fileperms to chmod is this:
substr(decoct(fileperms("test")),3);
Displays 666 or 777 (depends on chmod set).
substr(decoct(fileperms("test")),2);
Displays 0666 or 0777 and refers immediately to the number set with chmod();

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.

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);
?>

A small function for the last 3 digits (777/755 ect.)
<?php
function getFilePermission($file) {
    $length = strlen(decoct(fileperms($file)))-3;
    return substr(decoct(fileperms($file)),$length);
}
?>

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
?>