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<?php
/**
*
* @package core
* @version $Id$
* @copyright (c) 2008 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/
/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
exit();
}
/**
* System-specific methods. For example chmod(), unlink()...
*
* @package core
*/
class phpbb_system extends phpbb_plugin_support
{
/**
* @var array required phpBB objects
*/
public $phpbb_required = array();
/**
* @var array Optional phpBB objects
*/
public $phpbb_optional = array();
/**
* @var array Holding some information for chmod()
*/
private $chmod_info = array();
/**
* Method for chmodding directories and files for internal use.
*
* This function determines owner and group whom the file belongs to and user and group of PHP and then set safest possible file permissions.
* The function determines owner and group from common.php file and sets the same to the provided file.
* The function uses bit fields to build the permissions.
* The function sets the appropiate execute bit on directories.
*
* Supported constants representing bit fields are:
*
* phpbb::CHMOD_ALL - all permissions (7)
* phpbb::CHMOD_READ - read permission (4)
* phpbb::CHMOD_WRITE - write permission (2)
* phpbb::CHMOD_EXECUTE - execute permission (1)
*
* NOTE: The function uses POSIX extension and fileowner()/filegroup() functions. If any of them is disabled, this function tries to build proper permissions, by calling is_readable() and is_writable() functions.
*
* @param string $filename The file/directory to be chmodded
* @param int $perms Permissions to set
*
* @return bool true on success, otherwise false
* @author faw, phpBB Group
* @access public
*/
public function chmod($filename, $perms = phpbb::CHMOD_READ)
{
// Return if the file no longer exists.
if (!file_exists($filename))
{
return false;
}
// Determine some common vars
if (empty($this->chmod_info))
{
if (!function_exists('fileowner') || !function_exists('filegroup'))
{
// No need to further determine owner/group - it is unknown
$this->chmod_info['process'] = false;
}
else
{
// Determine owner/group of common.php file and the filename we want to change here
$common_php_owner = fileowner(PHPBB_ROOT_PATH . 'common.' . PHP_EXT);
$common_php_group = filegroup(PHPBB_ROOT_PATH . 'common.' . PHP_EXT);
// And the owner and the groups PHP is running under.
$php_uid = (function_exists('posix_getuid')) ? @posix_getuid() : false;
$php_gids = (function_exists('posix_getgroups')) ? @posix_getgroups() : false;
if (!$php_uid || empty($php_gids) || !$common_php_owner || !$common_php_group)
{
$this->chmod_info['process'] = false;
}
else
{
$this->chmod_info = array(
'process' => true,
'common_owner' => $common_php_owner,
'common_group' => $common_php_group,
'php_uid' => $php_uid,
'php_gids' => $php_gids,
);
}
}
}
if ($this->chmod_info['process'])
{
$file_uid = fileowner($filename);
$file_gid = filegroup($filename);
// Change owner
if (@chown($filename, $this->chmod_info['common_owner']))
{
clearstatcache();
$file_uid = fileowner($filename);
}
// Change group
if (@chgrp($filename, $this->chmod_info['common_group']))
{
clearstatcache();
$file_gid = filegroup($filename);
}
// If the file_uid/gid now match the one from common.php we can process further, else we are not able to change something
if ($file_uid != $this->chmod_info['common_owner'] || $file_gid != $this->chmod_info['common_group'])
{
$this->chmod_info['process'] = false;
}
}
// Still able to process?
if ($this->chmod_info['process'])
{
if ($file_uid == $this->chmod_info['php_uid'])
{
$php = 'owner';
}
else if (in_array($file_gid, $this->chmod_info['php_gids']))
{
$php = 'group';
}
else
{
// Since we are setting the everyone bit anyway, no need to do expensive operations
$this->chmod_info['process'] = false;
}
}
// We are not able to determine or change something
if (!$this->chmod_info['process'])
{
$php = 'other';
}
// Owner always has read/write permission
$owner = phpbb::CHMOD_READ | phpbb::CHMOD_WRITE;
if (is_dir($filename))
{
$owner |= phpbb::CHMOD_EXECUTE;
// Only add execute bit to the permission if the dir needs to be readable
if ($perms & phpbb::CHMOD_READ)
{
$perms |= phpbb::CHMOD_EXECUTE;
}
}
switch ($php)
{
case 'owner':
$result = @chmod($filename, ($owner << 6) + (0 << 3) + (0 << 0));
clearstatcache();
if (!is_null($php) || (is_readable($filename) && is_writable($filename)))
{
break;
}
case 'group':
$result = @chmod($filename, ($owner << 6) + ($perms << 3) + (0 << 0));
clearstatcache();
if (!is_null($php) || ((!($perms & phpbb::CHMOD_READ) || is_readable($filename)) && (!($perms & phpbb::CHMOD_WRITE) || is_writable($filename))))
{
break;
}
case 'other':
$result = @chmod($filename, ($owner << 6) + ($perms << 3) + ($perms << 0));
clearstatcache();
if (!is_null($php) || ((!($perms & phpbb::CHMOD_READ) || is_readable($filename)) && (!($perms & phpbb::CHMOD_WRITE) || is_writable($filename))))
{
break;
}
default:
return false;
break;
}
return $result;
}
}
?>
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