egroupware/phpgwapi/inc/class.links_stream_wrapper.inc.php
Ralf Becker 7282d42f52 - added hooks to general vfs methods to allow apps to monitore file access, creating, modification, removal
- new $user parameter for egw_vfs::check_access($path, $check, $stat=null, $user=null) to check access to a file for a user, who is NOT the current user
2011-06-23 18:34:47 +00:00

257 lines
10 KiB
PHP

<?php
/**
* eGroupWare API: VFS - stream wrapper for linked files
*
* @link http://www.egroupware.org
* @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
* @package api
* @subpackage vfs
* @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @copyright (c) 2008-10 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @version $Id: class.sqlfs_stream_wrapper.inc.php 24997 2008-03-02 21:44:15Z ralfbecker $
*/
/**
* Define parent for links_stream_wrapper, if not already defined
*
* Allows to base links_stream_wrapper on an other wrapper
*/
if (!class_exists('links_stream_wrapper_parent',false))
{
class links_stream_wrapper_parent extends sqlfs_stream_wrapper {}
}
/**
* eGroupWare API: stream wrapper for linked files
*
* The files stored by the sqlfs_stream_wrapper in a /apps/$app/$id directory
*
* The links stream wrapper extends the sqlfs one, to implement an own ACL based on the access
* of the entry the files are linked to.
*
* Applications can define a 'file_access' method in the link registry with the following signature:
*
* boolean function file_access(string $id,int $check,string $rel_path)
*
* If the do not implement such a function the title function is used to test if the user has
* at least read access to an entry, and if true full (write) access to the files is granted.
*
* The stream wrapper interface is according to the docu on php.net
*
* @link http://www.php.net/manual/en/function.stream-wrapper-register.php
*/
class links_stream_wrapper extends links_stream_wrapper_parent
{
/**
* Scheme / protocoll used for this stream-wrapper
*/
const SCHEME = 'links';
/**
* Prefix to predend to get an url from a path
*/
const PREFIX = 'links://default';
/**
* Base url to store links
*/
const BASEURL = 'links://default/apps';
/**
* Enable some debug output to the error_log
*/
const DEBUG = false;
/**
* Clears our stat-cache
*
* Normaly not necessary, as it is automatically cleared/updated, UNLESS egw_vfs::$user changes!
*
* We have to clear file_access cache of egw_link, as our ACL depends on it!
*
* @param string $path='/apps' to be able to clear only file_access cache of a certain app
*/
public static function clearstatcache($path='/apps')
{
//error_log(__METHOD__."('$path')");
if ($path[0] != '/') $path = parse_url($path, PHP_URL_PATH);
list(,,$app) = explode('/',$path);
egw_link::delete_cache($app, null); // null = delete only file_access cache, if app implements it, otherwise title cache is deleted too
// need to call sqlfs clearstatcache too
parent::clearstatcache($path);
}
/**
* Implements ACL based on the access of the user to the entry the files are linked to.
*
* @param string $url url to check
* @param int $check mode to check: one or more or'ed together of: 4 = read, 2 = write, 1 = executable
* @return boolean
*/
static function check_extended_acl($url,$check)
{
if (egw_vfs::$is_root)
{
return true;
}
$path = parse_url($url,PHP_URL_PATH);
list(,$apps,$app,$id,$rel_path) = explode('/',$path,5);
if ($apps != 'apps')
{
$access = false; // no access to anything, but /apps
}
elseif (!$app)
{
$access = !($check & egw_vfs::WRITABLE); // always grant read access to /apps
}
elseif(!isset($GLOBALS['egw_info']['user']['apps'][$app]))
{
$access = false; // user has no access to the $app application
}
elseif (!$id)
{
$access = true; // grant read&write access to /apps/$app
}
// allow applications to implement their own access control to the file storage
// otherwise use the title method to check if user has (at least read access) to the entry
// which gives him then read AND write access to the file store of the entry
else
{
// vfs & stream-wrapper use posix rights, egw_link::file_access uses EGW_ACL_{EDIT|READ}!
$required = $check & egw_vfs::WRITABLE ? EGW_ACL_EDIT : EGW_ACL_READ;
$access = egw_link::file_access($app,$id,$required,$rel_path);
}
if (self::DEBUG) error_log(__METHOD__."($url,$check) ".($access?"access granted ($app:$id:$rel_path)":'no access!!!'));
return $access;
}
/**
* This method is called in response to stat() calls on the URL paths associated with the wrapper.
*
* Reimplemented from sqlfs, as we have to pass the value of check_extends_acl(), due to the lack of late static binding.
*
* @param string $path
* @param int $flags holds additional flags set by the streams API. It can hold one or more of the following values OR'd together:
* - STREAM_URL_STAT_LINK For resources with the ability to link to other resource (such as an HTTP Location: forward,
* or a filesystem symlink). This flag specified that only information about the link itself should be returned,
* not the resource pointed to by the link.
* This flag is set in response to calls to lstat(), is_link(), or filetype().
* - STREAM_URL_STAT_QUIET If this flag is set, your wrapper should not raise any errors. If this flag is not set,
* you are responsible for reporting errors using the trigger_error() function during stating of the path.
* stat triggers it's own warning anyway, so it makes no sense to trigger one by our stream-wrapper!
* @return array
*/
static function url_stat ( $url, $flags )
{
return parent::url_stat($url,$flags,self::check_extended_acl($url,egw_vfs::READABLE));
}
/**
* Set or delete extended acl for a given path and owner (or delete them if is_null($rights)
*
* Reimplemented, to NOT call the sqlfs functions, as we dont allow to modify the ACL (defined by the apps)
*
* @param string $path string with path
* @param int $rights=null rights to set, or null to delete the entry
* @param int/boolean $owner=null owner for whom to set the rights, null for the current user, or false to delete all rights for $path
* @param int $fs_id=null fs_id to use, to not query it again (eg. because it's already deleted)
* @return boolean true if acl is set/deleted, false on error
*/
static function eacl($path,$rights=null,$owner=null,$fs_id=null)
{
return false;
}
/**
* Get all ext. ACL set for a path
*
* Reimplemented, to NOT call the sqlfs functions, as we dont allow to modify the ACL (defined by the apps)
*
* @param string $path
* @return array/boolean array with array('path'=>$path,'owner'=>$owner,'rights'=>$rights) or false if $path not found
*/
function get_eacl($path)
{
return false;
}
/**
* mkdir for links
*
* Reimplemented as we have no static late binding to allow the extended sqlfs to call our eacl and to set no default rights for entry dirs
*
* This method is called in response to mkdir() calls on URL paths associated with the wrapper.
*
* It should attempt to create the directory specified by path.
* In order for the appropriate error message to be returned, do not define this method if your wrapper does not support creating directories.
*
* @param string $path
* @param int $mode not used(!), we inherit 005 for /apps/$app and set 000 for /apps/$app/$id
* @param int $options Posible values include STREAM_REPORT_ERRORS and STREAM_MKDIR_RECURSIVE, we allways use recursive!
* @return boolean TRUE on success or FALSE on failure
*/
static function mkdir($path,$mode,$options)
{
if($path[0] != '/')
{
if (strpos($path,'?') !== false) $query = parse_url($path,PHP_URL_QUERY);
$path = parse_url($path,PHP_URL_PATH).($query ? '?'.$query : '');
}
list(,$apps,$app,$id,$rel_path) = explode('/',$path,5);
$ret = false;
if ($apps == 'apps' && $app && !$id || self::check_extended_acl($path,egw_vfs::WRITABLE)) // app directory itself is allways ok
{
$current_is_root = egw_vfs::$is_root; egw_vfs::$is_root = true;
$current_user = egw_vfs::$user; egw_vfs::$user = 0;
$ret = parent::mkdir($path,0,$options|STREAM_MKDIR_RECURSIVE);
if ($id) parent::chmod($path,0); // no other rights
egw_vfs::$user = $current_user;
egw_vfs::$is_root = $current_is_root;
}
//error_log(__METHOD__."($path,$mode,$options) apps=$apps, app=$app, id=$id: returning $ret");
return $ret;
}
/**
* This method is called immediately after your stream object is created.
*
* Reimplemented from sqlfs to ensure self::url_stat is called, to fill sqlfs stat cache with our eacl!
*
* @param string $url URL that was passed to fopen() and that this object is expected to retrieve
* @param string $mode mode used to open the file, as detailed for fopen()
* @param int $options additional flags set by the streams API (or'ed together):
* - STREAM_USE_PATH If path is relative, search for the resource using the include_path.
* - STREAM_REPORT_ERRORS If this flag is set, you are responsible for raising errors using trigger_error() during opening of the stream.
* If this flag is not set, you should not raise any errors.
* @param string $opened_path full path of the file/resource, if the open was successfull and STREAM_USE_PATH was set
* @return boolean true if the ressource was opened successful, otherwise false
*/
function stream_open ( $url, $mode, $options, &$opened_path )
{
// the following call is necessary to fill sqlfs_stream_wrapper::$stat_cache, WITH the extendes ACL!
self::url_stat($url,0);
return parent::stream_open($url,$mode,$options,$opened_path);
}
/**
* This method is called in response to rename() calls on URL paths associated with the wrapper.
*
* Reimplemented to use our own url_stat and unlink function (workaround for no lsb in php < 5.3)
*
* @param string $url_from
* @param string $url_to
* @param string $class=__CLASS__ class to use to call static methods, eg url_stat (workaround for no late static binding in php < 5.3)
* @return boolean TRUE on success or FALSE on failure
*/
static function rename ( $url_from, $url_to, $class=__CLASS__)
{
return parent::rename($url_from,$url_to,$class);
}
}
stream_register_wrapper(links_stream_wrapper::SCHEME ,'links_stream_wrapper');