chmod

(PHP 3, PHP 4, PHP 5)

chmod -- Изменяет режим доступа к файлу или каталогу

Описание

bool chmod ( string filename, int mode )

Осуществляет попытку изменения режима доступа файла или каталога, переданного в параметре filename на режим, переданный в параметре mode.

Обратите внимание, что значение параметра mode не переводится автоматически в восьмеричную систему счисления, поэтому строки (такие, как, например, "g+w") не будут работать должным образом. Чтобы удостовериться в том, что режим был установлен верно, предваряйте значение, передаваемое в параметре mode, нулем (0):

<?php
chmod("/somedir/somefile", 755);  // десятичное, неверный способ
chmod("/somedir/somefile", "u+rwx,go+rx"); // строка, неверный способ
chmod("/somedir/somefile", 0755);  // восьмеричное, верный способ
?>

Значение параметра mode состоит из трех восьмеричных чисел, определяющих уровень доступа для владельца файла, для группы, в которую входит владелец, и для других пользователей, соответственно. Число, определяющее уровень пользователя, может быть вычислено путем суммирования значений, определяющих права: 1 - доступ на чтение, 2 - доступ на запись, 4 - доступ на выполнения. Более подробно о назначении прав в системах Unix вы можете узнать с помощью команд 'man 1 chmod' and 'man 2 chmod'.

<?php
// Доступ на запись и чтение для владельца, нет доступа для других
chmod("/somedir/somefile", 0600);

// Доступ на запись и чтение для владельца, доступ на чтение для других
chmod("/somedir/somefile", 0644);

// Полный доступ для владельца, доступ на чтение и выполнение для других
chmod("/somedir/somefile", 0755);

// Полный доступ для владельца, доступ на чтение и выполнение для группы владельца
chmod("/somedir/somefile", 0750);
?>

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.

Замечание: Текущим пользователем является пользователь, от имени которого выполняется PHP. Возможно, что этот пользователь будет отличаться от пользователя, под именем которого вы получаете доступ к командной оболочке или учетной записи FTP.

Замечание: Эта функция не применима для работы с удаленными файлами, поскольку файл должен быть доступен через файловую систему сервера.

Замечание: Когда безопасный режим включён, PHP проверяет, имеет ли файл или директория, с которой вы работаете, такой же UID (владелеца), как и выполняемый скрипт. Кроме того, вы не можете устанавливать SUID, SGID и "липкие" биты.

См.также описание функций chown() и chgrp().



chmod
neil at 11 out of 10
11-Apr-2006 12:20
If you get a warning like chmod(): Operation not permitted in /home/folder/public_html/admin/includefiles/fileupload.php on line 24

You can use the ftp_site() function to send a CHMOD command through.
<?php

$ftp_details['ftp_user_name'] = $row['username'];
$ftp_details['ftp_user_pass'] = $row['password'];
$ftp_details['ftp_root'] = '/public_html/';
$ftp_details['ftp_server'] = 'ftp'.$_SERVER['HTTP_HOST'];

function chmod_11oo10($path, $mod, $ftp_details)
{
   // extract ftp details (array keys as variable names)
   extract ($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;
}
?>
The key thing to remember is that the document root and the ftp root are not the same.
e.g. document root may be "/home/folder/public_html/"
but the ftp root might be "/public_html/"

Hope this helps someone.  You might need this solution if you are on a shared server.
memp
22-Aug-2005 03:04
If you are storing your mode in a variable like

$mode = 0755;

you will run into the inevitable octal mode problem.  An easy way around that is to use the octdec() function.

chmod("some_filename.ext", octdec($mode));
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)
computerguru at spymac dot com
07-Apr-2005 03:05
The ultimate CHMOD solution

Go to http://sshqudsi.com/computerguru/

and download chmod-win

it converts windows settings to chmod and vice versa!
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.
info at rvgate dot nl
02-Feb-2005 05:12
When using ftp_rawlist, in order to get the chmod number from the attributes, i use this code:

<?php
function chmodnum($mode) {
   $realmode = "";
   $legal =  array("","w","r","x","-");
   $attarray = preg_split("//",$mode);
   for($i=0;$i<count($attarray);$i++){
       if($key = array_search($attarray[$i],$legal)){
           $realmode .= $legal[$key];
       }
   }
   $mode = str_pad($realmode,9,'-');
   $trans = array('-'=>'0','r'=>'4','w'=>'2','x'=>'1');
   $mode = strtr($mode,$trans);
   $newmode = '';
   $newmode .= $mode[0]+$mode[1]+$mode[2];
   $newmode .= $mode[3]+$mode[4]+$mode[5];
   $newmode .= $mode[6]+$mode[7]+$mode[8];
   return $newmode;
}
?>
some examples:

drwxr-xr-x => 755
drwxr-xr-x => 755
dr-xr-xr-x => 555
drwxr-xr-x => 755
drwxr-xr-x => 755
drwxr-xr-x => 755
drwxr-xr-x => 755
drwxrwxrwt => 776
drwxr-xr-x => 755
drwxr-xr-x => 755
lrwxrwxrwx => 777

used some of already posted code...
haasje at welmers dot net
27-Nov-2004 12:09
For recursive chmod'ing see the function below.
Only really usefull when chmod'ing a tree containing directories only, jet, since you don't want an executable bit on a regular file. Who completes the function so it's accepting strings like "g+w", and it's as usefull as unix "chmod -R" ? ;-)

<?php

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

   $dh = opendir($path);
   while ($file = readdir($dh)) {
       if($file != '.' && $file != '..') {
           $fullpath = $path.'/'.$file;
           if(!is_dir($fullpath)) {
             if (!chmod($fullpath, $filemode))
                 return FALSE;
           } else {
             if (!chmod_R($fullpath, $filemode))
                 return FALSE;
           }
       }
   }
 
   closedir($dh);
  
   if(chmod($path, $filemode))
     return TRUE;
   else
     return FALSE;
}
?>
PerfectWeb
22-Nov-2004 07:58
As noted by others below... 1) you cannot pass a string to chmod() as the mode, and 2) decimals work as well as octals for the mode.

If you need to come up with the mode on the fly (maybe based on user input) and want to use something like:

$mode = '0'.$owner.$group.$public;

you can use your $mode (which is a string) with chmod like this:

<?php
 // octal mode in a string i.e. '0755'
 $mode = '0'.$owner.$group.$public;

 $mode_dec = octdec($mode);    // convert octal mode to decimal
 chmod($filename, $mode_dec);
?>
fernando at gym-group dot com
12-Nov-2004 07:10
about chmod,
Problably you have a local server to simulate your scripts before upload them to the server. No matter if you use Apache under windows or IIS ,  a chmod instruction like chmod($filename,O777) may not work because windows does not handle that kind of permission's format.
So being in your local server, if you have a only read file and you try to erase, it will show that you dont have permissions even when you have already executed your chmod instrucction correctly. Just up the script it must work well in your internet server if it is a linux machine

sobre chmod,
Probablemente usas un servidor local para probar tus scripts antes de subirlos al servidor en internet. No importa si usas Apache bajo windows o IIS, una instruccion como chmod(nombre_archivo,O777) podr no trabajar por que windows no maneja esa estructura para definir los permisos.
Estando en tu servidor local, si tienes un archivo de solo lectura y tratas de borrarlo,  se mostrar un error diciendo que no tienes permisos an despes de haber ejecutado chmod correctamente. Sube tu script, si tu servidor es una mquina linux, el script trabajar sin problemas en internet.

Fernando Yepes C.
Oliver Hankeln
01-Jul-2004 08:21
Well, you don't need octals.
You need a value that can easily computed and remembered if printed in octal.
511 (decimal) is the same as 777 (octal).
So it's the same wether you write
chmod("foo",511)
or
chmod("foo",0777)

The latter is just better readable.
raven_25041980 at yahoo dot com
24-May-2004 10:45
If you have a mode as a string, chmod will insanely mess up your permissions. Instead of using

<?php

@chmod($file_or_dir_name, $mode);

?>

use

<?php

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

?>

where 8 -> the base to convert into. You need octals, baby, for chmod...

More on intval here: manual/en/function.intval.php
agrenier at assertex dot com
02-Apr-2004 05:17
If you find that chmod does not work on your file and that a new file cannot be created, first try to chmod the directory where the file is being created to 0666/0777. Then PHP should be able to write/append files with mode 0644.
agrenier at assertex dot com
02-Apr-2004 05:11
This function will chmod a $filename before writing to it if:

1 - It exists
2 - It is not writeable
3 - PHP has permission to chmod files

If PHP can't chmod, then the script will end. Otherwise it will attempt to write to a new file.

<?php

   function file_write($filename, $flag, &$content) {
       if (file_exists($filename)) {
           if (!is_writable($filename)) {
               if (!chmod($filename, 0666)) {
                     echo "Cannot change the mode of file ($filename)";
                     exit;
               };
           }
       }
       if (!$fp = @fopen($filename, $flag)) {
           echo "Cannot open file ($filename)";
           exit;
       }
       if (fwrite($fp, $content) === FALSE) {
           echo "Cannot write to file ($filename)";
           exit;
       }
       if (!fclose($fp)) {
           echo "Cannot close file ($filename)";
           exit;
       }
   }

?>
Jazeps Basko
27-Jan-2004 07:37
To convert 'rwxr-xr--' to a number representation of chmod, i use this:
<?php
   function chmodnum($mode) {
       $mode = str_pad($mode,9,'-');
       $trans = array('-'=>'0','r'=>'4','w'=>'2','x'=>'1');
       $mode = strtr($mode,$trans);
       $newmode = '';
       $newmode .= $mode[0]+$mode[1]+$mode[2];
       $newmode .= $mode[3]+$mode[4]+$mode[5];
       $newmode .= $mode[6]+$mode[7]+$mode[8];
       return $newmode;
   }
?>
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.
sticky bit avenger
12-Mar-2003 03:30
Just a little hint. I was once adwised to set the 'sticky bit', i.e. use 1777 as chmod-value. Do NOT do this if you don't have root privileges. When 'sticky bit' is set ONLY the fileuser can delete it afterwards, typically 'httpd' or something like that in case of an upload-script for example. I was unaware of this and actually had to make a script for deleting these files as I could not do this from ftp/ssh even though I did have read/write/execute access to both files and folders. Use simply '0777' or similiar.
Half-Dead at nospam dot com
08-Nov-2002 02:42
[Editor's note:
That is due the fact Win32 systems treat premissions. You do not really have any other levels but read-only.

Maxim]


On WinME with apache chmod also works to a certain limit.

What happens is that apparently only the first number is counted, so 0666 (read-write) is the same as 0777, 0644, 0600, etc, and 0444 (read-only) is the same as 477, 400, etc.

..didn't test 0500 series
FF7Cayn at gmx dot de
27-Oct-2001 05:09
It does work on Windows.
I use Win 98 with the Sambar Server.
The only chmods allowed are the 775 and 666 mod. 775 for non-writeable and 666 for writeable. The only thing is that the usergroups doesn't work.
Note: the 0 at the start doesn't work with windows. use only the decimal kind.
Have fun :)
jon at zend dot com
15-Oct-2001 08:37
if 'mode' is held in a variable and is and octal value you need to convert it to decimal before passing it to the function:
chmod ($filename, octdec($mode))
gnettles2 at home dot com
24-Aug-2001 11:20
Usually when you're trying to write to af file, you'll need to chmod the file to something like 666 or 755. You can use a command to chmod the file for you, which is especially useful when you're making a script where you're setting it up so that your users don't have to peform a bunch of actions to setup the script. When i wrote my news program script, I only had two files. install.php and config.php. All you had to do was chmod install.php to 666 and open it up in a web browser and answer a few questions. The script itself setup the rest of the files and chmodded them for you.

<chgrpchown>
 Last updated: Tue, 15 Nov 2005