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chmod

(PHP 4, PHP 5, PHP 7, PHP 8)

chmod — Cambia el modo de un fichero

Descripción

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

Intenta cambiar el modo de un fichero especificado por el dado en mode.

Parámetros

filename

Ruta del fichero.

mode

Observe que no se asume que mode sea automáticamente un valor octal, por lo que, para asegurarse de que la operación sea la esperada, es necesario prefijar mode con un cero (0). String tales como "g+w" no funcionarán adecuadamente.

<?php
chmod("/directorio/fichero", 755);   // decimal; probablemente incorrecto
chmod("/directorio/fichero", "u+rwx,go+rx"); // string; incorrecto
chmod("/directorio/fichero", 0755);  // octal; valor de modo correcto
?>

El parámetro mode consiste en tres componentes numéricos octales que especifican las restricciones de acceso para el propietario, el grupo de usuarios al que pertenece el propietario, y para todos los demás, en este orden. Un componente puede ser computado sumando los permisos necesarios para ese usuario objetivo base. El número 1 significa que se conceden derechos de ejecución, el número 2 significa que se puede escribir en el fichero, el número 4 significa que el fichero se puede leer. Sume estos números para especificar los derechos necesarios. Se puede leer más sobre los modos en sistemas Unix con 'man 1 chmod' y 'man 2 chmod'.

<?php
// Lectura y escritura para el propietario, nada para los demás
chmod("/directorio/fichero", 0600);

// Lectura y escritura para el propietario, lectura para los demás
chmod("/directorio/fichero", 0644);

// Todo para el propietario, lectura y ejecución para los otros
chmod("/directorio/fichero", 0755);

// Todo para el propietario, lectura y ejecución para el grupo del propietario
chmod("/directorio/fichero", 0750);
?>

Valores devueltos

Devuelve true en caso de éxito o false en caso de error.

Notas

Nota:
El usuario actual es el usuario bajo el que se ejecuta PHP. Probablemente no sea el mismo usuario que se utilize para el intérprete de comandos normal o el acceso FTP. EL modo puede ser cambiado sólo por el usuario al que pertenece el fichero en la mayoría de sistemas.

Nota: Esta función no funcionará en ficheros remotos ya que el fichero debe ser accesible vía el sistema de ficheros del servidor para poder ser examinado.

Ver también

chown() - Cambia el propietario del fichero
chgrp() - Cambia el grupo del archivo
fileperms() - Obtiene los permisos de un fichero
stat() - Da información acerca de un fichero

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User Contributed Notes 17 notes

down

MethodicalFool ¶

14 years ago


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

down

Geoff W ¶

14 years ago


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

down

masha at mail dot ru ¶

19 years ago


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)

down

no at no dot es ¶

3 years ago


use a stored string for the mask is a pain
ex: $mask contains a string 0755
int($mask) not work (return 755)
the only way i found is use octdec($mask)

down

pmichaud at pobox dot com ¶

21 years ago


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.

down

alex at feidesign dot com ¶

19 years ago


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.

down

paul maybe at squirrel mail org ¶

16 years ago


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);

?>

down

Anonymous ¶

15 years ago


Changes file mode recursive in $pathname to $filemode

<?php

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

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

?>

down

Tuckbros ¶

4 years ago


Just an update of the solution with octdec. You have to give octdec the string as a parameter.

$mode = '644';
chmod(file_or_dir_name, octdec($mode));

See also: http://www.php.net/manual/en/function.octdec.php

down

chris at ocproducts dot com ¶

4 years ago


Windows has a very different file permission model to Unix and integrates them only minimally.

On Windows, all this function can do is to change the "read only" flag, which is turned on if $mode & 0200 does not pass.
i.e. it only checks if u+w is missing from the bitmask, and if it is, it sets the read only flag.

The executable flag cannot be set as Windows determines it based on file extension.
The write flag cannot be set as Windows determines write access based on ACLs, which are not integrated here.

down

imoldgreg at o2 dot co dot uk ¶

18 years ago


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!

down

Andrey P. ¶

13 years ago


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.

down

h dot kuppens at cs dot ru dot nl ¶

13 years ago


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;

        }

    }

}

?>

down

sander ¶

15 years ago


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);

}

?>

down

nicolas at infosoft dot inf dot br ¶

16 years ago


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

down

Ambriel_Angel at www dot ambriels dot net/entry ¶

17 years ago


<?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



?>

down

webmaster at danopia dot 5gigs dot com ¶

17 years ago


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.

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