php教程

chmod

(PHP 4, PHP 5, PHP 7)

chmod — 改变文件模式

说明

chmod ( string $filename , int $mode ) : bool

尝试将 filename 所指定文件的模式改成 mode 所给定的。

参数

filename

文件的路径。

mode

注意 mode 不会被自动当成八进制数值，而且也不能用字符串（例如 "g+w"）。要确保正确操作，需要给 mode 前面加上 0：

<?php
chmod("/somedir/somefile", 755);   // 十进制数，可能不对
chmod("/somedir/somefile", "u+rwx,go+rx"); // 字符串，不对
chmod("/somedir/somefile", 0755);  // 八进制数，正确的 mode 值
?>

mode 参数包含三个八进制数按顺序分别指定了所有者、所有者所在的组以及所有人的访问限制。每一部分都可以通过加入所需的权限来计算出所要的权限。数字 1 表示使文件可执行，数字 2 表示使文件可写，数字 4 表示使文件可读。加入这些数字来制定所需要的权限。有关 UNIX 系统的文件权限可以阅读手册"man 1 chmod"和"man 2 chmod"。

<?php
// Read and write for owner, nothing for everybody else
chmod("/somedir/somefile", 0600);

// Read and write for owner, read for everybody else
chmod("/somedir/somefile", 0644);

// Everything for owner, read and execute for others
chmod("/somedir/somefile", 0755);

// Everything for owner, read and execute for owner's group
chmod("/somedir/somefile", 0750);
?>

返回值

成功时返回 TRUE， 或者在失败时返回 FALSE。

注释

Note:

当前用户指的是执行 PHP 的用户。很可能和通常的 shell 或者 FTP 用户不是同一个。在大多数系统下文件模式只能被文件所有者的用户改变。

Note: 此函数不能作用于远程文件，被检查的文件必须是可通过服务器的文件系统访问的。

Note:

当安全模式打开的时候，PHP 会检查所操作的文件是否和正在执行的脚本具有相同的 UID （所有者）。要注意的是，不能修改 SUID，SGID 和 sticky bits。

参见

User Contributed Notes

h dot kuppens at cs dot ru dot nl 29-Aug-2011 02:51
For recursive chmod'ing both files and directories in one step you can use the function below. Note that this function has one argument for directory permissions and one for file permissions.
In this way you can apply the 'x' permission on directories, and skip it on directories. This function also skips links.

Example usage :

   chmod_R( 'mydir', 0666, 0777);

Makes all files and directories within mydir/ directory accessible for everyone, but doesn't make the files executable.

I guess for very deeply nested directories the recursion with php can become problematic, but I can be wrong because I never investigated this.

<?php
function chmod_R($path, $filemode, $dirmode) {
    if (is_dir($path) ) {
        if (!chmod($path, $dirmode)) {
            $dirmode_str=decoct($dirmode);
            print "Failed applying filemode '$dirmode_str' on directory '$path'\n";
            print "  `-> the directory '$path' will be skipped from recursive chmod\n";
            return;
        }
        $dh = opendir($path);
        while (($file = readdir($dh)) !== false) {
            if($file != '.' && $file != '..') {  // skip self and parent pointing directories
                $fullpath = $path.'/'.$file;
                chmod_R($fullpath, $filemode,$dirmode);
            }
        }
        closedir($dh);
    } else {
        if (is_link($path)) {
            print "link '$path' is skipped\n";
            return;
        }
        if (!chmod($path, $filemode)) {
            $filemode_str=decoct($filemode);
            print "Failed applying filemode '$filemode_str' on file '$path'\n";
            return;
        }
    }
}
?>
Andrey P. 01-Mar-2011 02:23
I was trying to change permissions of a folder with chmod command with FTP connection. (I needed a writable folder to upload pictures with php)

I got the following respond:
"SITE CHMOD 777 uploads: command not understood"

The reason: Server is running under Windows system that does not allow to set file permissions via FTP. Conversely, the UNIX-running servers allow that.

Solutions:

1. If your web hosting provider has a web-based control panel that lets you set file permissions, then you need to login there and make changes.

2. It is possible to contact the hosting provider and ask them about this issue; maybe they can make the changes.

3. It is possible to change the hosting provider that has servers run on UNIX, and keep the site there.
MethodicalFool 02-Sep-2010 09:46
BEWARE, a couple of the examples in the comments suggest doing something like this:

chmod(file_or_dir_name, intval($mode, 8));

However, if $mode is an integer then intval( ) won't modify it.  So, this code...

$mode = 644;
chmod('/tmp/test', intval($mode, 8));

...produces permissions that look like this:

1--w----r-T

Instead, use octdec( ), like this:

chmod(file_or_dir_name, octdec($mode));

See also: http://www.php.net/manual/en/function.octdec.php
Geoff W 08-Feb-2010 02:13
BEWARE using quotes around the second parameter...

If you use quotes eg

chmod (file, "0644");

php will not complain but will do an implicit conversion to an int before running chmod. Unfortunately the implicit conversion doesn't take into account the octal string so you end up with an integer version 644, which is 1204 octal
sander 25-Jun-2009 11:06
if you want to chmod directories too, use this

<?php
$iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($pathname), RecursiveIteratorIterator::SELF_FIRST);

foreach($iterator as $item) {
    chmod($item, $filemode);
}
?>
Anonymous 24-Dec-2008 02:14
Changes file mode recursive in $pathname to $filemode

<?php

$iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($pathname));

foreach($iterator as $item) {
    chmod($item, $filemode);
}

?>
nicolas at infosoft dot inf dot br 07-Jul-2008 05:37
I use the code of haasje@welmers.net, but have a lite alteration. (linux symlink)

<?php
function chmod_R($path, $filemode) {
    if (!is_dir($path))
        return chmod($path, $filemode);

    $dh = opendir($path);
    while (($file = readdir($dh)) !== false) {
        if($file != '.' && $file != '..') {
            $fullpath = $path.'/'.$file;
            if(is_link($fullpath))
                return FALSE;
            elseif(!is_dir($fullpath))
                if (!chmod($fullpath, $filemode))
                    return FALSE;
            elseif(!chmod_R($fullpath, $filemode))
                return FALSE;
        }
    }

    closedir($dh);

    if(chmod($path, $filemode))
        return TRUE;
    else
        return FALSE;
}
?>
thanks alls
paul maybe at squirrel mail org 24-Apr-2008 05:09
Note that info at rvgate dot nl's chmodnum function produces INCORRECT results.  The resutls are base-10 numbers that only LOOK like they are octal numbers.  The function also ignores setuid, setgid and sticky bits, and will produce incorrect numbers if such a file is encountered.  Instead, this brute-force code works.  Maybe there is something more slick, but this isn't too CPU-intensive (note that it assumes you've error-checked that you indeed have a 10-character string!):

<?php
      $permissions = 'drwxr-xr-x';  // or whatever
      $mode = 0;

      if ($permissions[1] == 'r') $mode += 0400;
      if ($permissions[2] == 'w') $mode += 0200;
      if ($permissions[3] == 'x') $mode += 0100;
      else if ($permissions[3] == 's') $mode += 04100;
      else if ($permissions[3] == 'S') $mode += 04000;

      if ($permissions[4] == 'r') $mode += 040;
      if ($permissions[5] == 'w') $mode += 020;
      if ($permissions[6] == 'x') $mode += 010;
      else if ($permissions[6] == 's') $mode += 02010;
      else if ($permissions[6] == 'S') $mode += 02000;

      if ($permissions[7] == 'r') $mode += 04;
      if ($permissions[8] == 'w') $mode += 02;
      if ($permissions[9] == 'x') $mode += 01;
      else if ($permissions[9] == 't') $mode += 01001;
      else if ($permissions[9] == 'T') $mode += 01000;

      printf('Mode is %d decimal and %o octal', $mode, $mode);
?>
Ambriel_Angel at www dot ambriels dot net/entry 25-Mar-2007 06:00
<?php
error_reporting(E_ERROR | E_PARSE);
/* Makes is so Directories are not browseable to the public,
removing only the Public = Read permission, while leaving
the other chmod permissions for the file in tact.

If you have exectue already on, and read off, public viewers will only
be able to view files through links, but not browse
around to see what's inside of directories and see what
you've got laying around. */
//-------------------------------------------------------
// Get file mode
// Get file permissions supported by chmod
function getmod($filename) {
   $val = 0;
   $perms = fileperms($filename);
   // Owner; User
   $val += (($perms & 0x0100) ? 0x0100 : 0x0000); //Read
   $val += (($perms & 0x0080) ? 0x0080 : 0x0000); //Write
   $val += (($perms & 0x0040) ? 0x0040 : 0x0000); //Execute
 
   // Group
   $val += (($perms & 0x0020) ? 0x0020 : 0x0000); //Read
   $val += (($perms & 0x0010) ? 0x0010 : 0x0000); //Write
   $val += (($perms & 0x0008) ? 0x0008 : 0x0000); //Execute
 
   // Global; World
   $val += (($perms & 0x0004) ? 0x0004 : 0x0000); //Read
   $val += (($perms & 0x0002) ? 0x0002 : 0x0000); //Write
   $val += (($perms & 0x0001) ? 0x0001 : 0x0000); //Execute

   // Misc
   $val += (($perms & 0x40000) ? 0x40000 : 0x0000); //temporary file (01000000)
   $val += (($perms & 0x80000) ? 0x80000 : 0x0000); //compressed file (02000000)
   $val += (($perms & 0x100000) ? 0x100000 : 0x0000); //sparse file (04000000)
   $val += (($perms & 0x0800) ? 0x0800 : 0x0000); //Hidden file (setuid bit) (04000)
   $val += (($perms & 0x0400) ? 0x0400 : 0x0000); //System file (setgid bit) (02000)
   $val += (($perms & 0x0200) ? 0x0200 : 0x0000); //Archive bit (sticky bit) (01000)

   return $val;
}

//-------------------------------------------------------
// Find out if file has mode
function hasmod($perms, $permission) {

# User Read = 0400 (256), Write = 0200 (128), Execute = 0100 (64)
# Group Read = 0040 (32), Write = 0020 (16), Execute = 0010 (8)
# Public Read = 0004 (4), Write = 0002 (2), Execute = 0001 (1)

    return (($perms & $permission) == $permission);
}

//-------------------------------------------------------
// Take the read option off of all the subdirectories of the included path
function pathlock($dir, $listall = false, $testrun = true) {
   echo "START @ " . date("F j, Y, h:i:s A") . "<br><br>";
   echo ($testrun ? '**Test Run Activated (no changes will be made).**<br><br>' : '**Live Run Activated.**<br><br>');
   echo $dir . " is our directory.<br><br>\n";
   echo "[...IN PROGRESS...]<br><br>";

   $file_list = '';
   $stack[] = $dir;
 
   while ($stack) {
      $current_dir = array_pop($stack);
      if ($dh = opendir($current_dir)) {
          while (($file = readdir($dh)) !== false) {
              if ($file !== '.' AND $file !== '..') {
                  $current_file = "{$current_dir}/{$file}";
               if (is_dir($current_file)) {
                      // BEG ADD PATH   
                   $mode = getmod($current_file);    //Get the mode
                      $HasPubRead = hasmod($mode,4);
                   if ($HasPubRead || $listall) {    // Can the public read this dir?
                  //======================================
                    $ch = true;
                  $take = 0;
                       // Change the mode:
                     if ($HasPubRead) {
                          $take = 4;         // Value for Public Read. 4 is the same in octal and decimal.
                          if (!$testrun) {
                              $ch = chmod($current_file, $mode-$take);
                          }
                      }

                    echo $current_file . ",current=" . decoct($mode) .
                        (($mode!==$mode-$take) ? ",new=" . decoct($mode-$take) : '') .
                        ($ch ? '' : ',FAILED') . "<br>\n";
                   } // end if hasmod
                   // END ADD PATH                          
                      $stack[] = $current_file;
                  } // if if_dir
              } //if ($file !== '.' AND $file !== '..')
          } //while (($file = readdir($dh)) !== false)
      } //if ($dh = opendir($current_dir))
} // while ($stack)

    echo "<br>COMPLETE @ " . date("F j, Y, h:i:s A") . "<br>\n";
return;
   //return $path_list;
} // end function

//-------------------------------------------------------
    //listall Show all folders, even one's we're not going to process?
    //testrun Do a test run without making any changes
    pathlock($_SERVER["DOCUMENT_ROOT"],false,true); // listall?=false, testrun?=true

?>
webmaster at danopia dot 5gigs dot com 02-Jan-2007 06:20
Thanks for your code, "imoldgreg at o2 dot co dot uk". I am using it for an instalation script that has to CHMOD a bunch of files. I have found it faster to use the same connectino for each, as shown below.

<?php

// Thanks to "imoldgreg at o2 dot co dot uk" for the base 'CHMOD via FTP' script.

function chmod_open()
{
    // Use your own FTP info
    $ftp_user_name = 'chmod@XXXXXXXXX.com';
    $ftp_user_pass = 'XXXXXXXXXX';
    $ftp_root = '/';
    $ftp_server = 'localhost';
    $conn_id = ftp_connect($ftp_server);
    $login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
    return $conn_id;
}

function chmod_file($conn_id, $permissions, $path)
{
    if (ftp_site($conn_id, 'CHMOD ' . $permissions . ' ' . $ftp_root . $path) !== false)
    {
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}

function chmod_close($conn_id)
{
    ftp_close($conn_id);
}

// CHMOD the required setup files

// Connect to the FTP
$conn_id = chmod_open();

// CHMOD each file and echo the results
echo chmod_file($conn_id, 777, 'master/cache/') ? 'CHMODed successfully!' : 'Error';
echo chmod_file($conn_id, 777, 'master/files/') ? 'CHMODed successfully!' : 'Error';
echo chmod_file($conn_id, 777, 'master/store/') ? 'CHMODed successfully!' : 'Error';
echo chmod_file($conn_id, 766, 'master/config.php') ? 'CHMODed successfully!' : 'Error';
echo chmod_file($conn_id, 777, 'master/images/avatars/upload/') ? 'CHMODed successfully!' : 'Error';

// Close the connection
chmod_close($conn_id);

?>

Here, the same FTP connection is used for each CHMOD command, making the execute time lower. This is essential for me, since my script is also copying a bunch of files.
imoldgreg at o2 dot co dot uk 30-Nov-2006 05:32
an update to 'neil at 11 out of 10's code for changing mode using FTP.

changes: proper array added within the function (better for those of us who only need to connect to one ftp server) so only the mode and directory name need to be passed.

the octal added, for completeness and predictable stability.

<?php
function changemode($xcite)
{
$ftp_details = array(
ftp_user_name => 'username',
ftp_user_pass => 'password',
ftp_user_root => '/public_html/',
ftp_server => 'ftp.something.org'
);

$path = "public";
$mod = intval($xcite, 8);

   // extract ftp details (array keys as variable names)
   extract ($ftp_details);
  
   // set up basic connection
   $conn_id = ftp_connect($ftp_server);
  
   // login with username and password
   $login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
  
   // try to chmod $path directory
   if (ftp_site($conn_id, 'CHMOD '.$mod.' '.$ftp_root.$path) !== false) {
       $success=TRUE;
   }
   else {
       $success=FALSE;
   }

   // close the connection
   ftp_close($conn_id);
    return $success;
}

?>

for those of you, like me, who were looking for a way to make an 'un-hackable' uploader, here's the closest i got, now for a field test, good luck!
masha at mail dot ru 10-Jul-2005 09:23
Usefull reference:

Value    Permission Level
400    Owner Read
200    Owner Write
100    Owner Execute
40    Group Read
20    Group Write
10    Group Execute
4    Global Read
2    Global Write
1    Global Execute

(taken from http://www.onlamp.com/pub/a/php/2003/02/06/php_foundations.html)
alex at feidesign dot com 01-Apr-2005 04:20
If you cannot chmod files/directories with PHP because of safe_mode restrictions, but you can use FTP to chmod them, simply use PHP's FTP-functions (eg. ftp_chmod or ftp_site) instead. Not as efficient, but works.
pmichaud at pobox dot com 19-Apr-2003 03:45
In the previous post, stickybit avenger writes:
    Just a little hint. I was once adwised to set the 'sticky bit', i.e. use 1777 as chmod-value...

Note that in order to set the sticky bit on a file one must use '01777' (oct) and not '1777' (dec) as the parameter to chmod:

<?php
    chmod("file",01777);   // correct
     chmod("file",1777);    // incorrect, same as chmod("file",01023), causing no owner permissions!
?>

Rule of thumb: always prefix octal mode values with a zero.

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