<chapter id="VFS">
<chapterinfo>
	&author.jelmer;
	&author.jht;
	<author><firstname>Tim</firstname><surname>Potter</surname></author>
	<author><firstname>Simo</firstname><surname>Sorce</surname><contrib>original vfs_skel README</contrib></author>
	<author><firstname>Alexander</firstname><surname>Bokovoy</surname><contrib>original vfs_netatalk docs</contrib></author>
	<author><firstname>Stefan</firstname><surname>Metzmacher</surname><contrib>Update for multiple modules</contrib></author>
</chapterinfo>
<title>Stackable VFS modules</title>

<sect1>
<title>Features and Benefits</title>

<para>
Since Samba-3, there is support for stackable VFS(Virtual File System) modules.  
Samba passes each request to access the unix file system thru the loaded VFS modules. 
This chapter covers all the modules that come with the samba source and references to 
some external modules.
</para>


</sect1>

<sect1>
<title>Discussion</title>

<para>
If not supplied with your platform distribution binary Samba package you may have problems
to compile these modules, as shared libraries are compiled and linked in different ways
on different systems.  They currently have been tested against GNU/Linux and IRIX.
</para>

<para>
To use the VFS modules, create a share similar to the one below.  The
important parameter is the <smbconfoption><name>vfs objects</name></smbconfoption> parameter where
you can list one or more VFS modules by name. For example, to log all access 
to files and put deleted files in a recycle bin:

<smbconfexample>
	<title>smb.conf with VFS modules</title>
	<smbconfsection>[audit]</smbconfsection>
<smbconfoption><name>comment</name><value>Audited /data directory</value></smbconfoption>
<smbconfoption><name>path</name><value>/data</value></smbconfoption>
<smbconfoption><name>vfs objects</name><value>audit recycle</value></smbconfoption>
<smbconfoption><name>writeable</name><value>yes</value></smbconfoption>
<smbconfoption><name>browseable</name><value>yes</value></smbconfoption>
	</smbconfexample>
</para>

<para>
The modules are used in the order in which they are specified.
</para>

<para>
Samba will attempt to load modules from the <emphasis>lib</emphasis>
directory in the root directory of the samba installation (usually 
<filename>/usr/lib/samba/vfs</filename> or <filename>/usr/local/samba/lib/vfs
</filename>).
</para>

<para>
Some modules can be used twice for the same share.
This can be done using a configuration similar to the one below.

<smbconfexample>
	<title>smb.conf with multiple VFS modules</title>
<smbconfsection>[test]</smbconfsection>
<smbconfoption><name>comment</name><value>VFS TEST</value></smbconfoption>
<smbconfoption><name>path</name><value>/data</value></smbconfoption>
<smbconfoption><name>writeable</name><value>yes</value></smbconfoption>
<smbconfoption><name>browseable</name><value>yes</value></smbconfoption>
<smbconfoption><name>vfs objects</name><value>example:example1 example example:test</value></smbconfoption>
<smbconfoption><name>example1: parameter</name><value>1</value></smbconfoption>
<smbconfoption><name>example:  parameter</name><value>5</value></smbconfoption>
<smbconfoption><name>test:	  parameter</name><value>7</value></smbconfoption>
</smbconfexample>
</para>

</sect1>

<sect1>
<title>Included modules</title>

	<sect2>
	<title>audit</title>

		<para>
		A simple module to audit file access to the syslog
		facility.  The following operations are logged:
		<itemizedlist>
		<listitem><para>share</para></listitem>
		<listitem><para>connect/disconnect</para></listitem>
		<listitem><para>directory opens/create/remove</para></listitem>
		<listitem><para>file open/close/rename/unlink/chmod</para></listitem>
		</itemizedlist>
		</para>

	</sect2>

	<sect2>
	<title>extd_audit</title>

		<para>
		This module is identical with the <emphasis>audit</emphasis> module above except
		that it sends audit logs to both syslog as well as the smbd log file/s. The 
		loglevel for this module is set in the smb.conf file. 
		</para>

		<para>
		The logging information that will be written to the smbd log file is controlled by
		the <smbconfoption><name>log level</name></smbconfoption> parameter in &smb.conf;. The
		following information will be recorded:
		</para>

		<table frame="all"><title>Extended Auditing Log Information</title>
		<tgroup cols="2" align="center">
			<thead>
			<row><entry align="center">Log Level</entry><entry>Log Details - File and Directory Operations</entry></row>
			</thead>
			<tbody>
			<row><entry align="center">0</entry><entry align="left">Creation / Deletion</entry></row>
			<row><entry align="center">1</entry><entry align="left">Create / Delete / Rename / Permission Changes</entry></row>
			<row><entry align="center">2</entry><entry align="left">Create / Delete / Rename / Perm Change / Open / Close</entry></row>
			</tbody>
		</tgroup>
		</table>

	</sect2>

	<sect2>
	<title>fake_perms</title>

		<para>
		This module was created to allow Roaming Profile files and directories to be set (on the Samba server
		under Unix) as read only. This module will if installed on the Profiles share will report to the client
		that the Profile files and directories are writable. This satisfies the client even though the files
		will never be overwritten as the client logs out or shuts down.
		</para>

	</sect2>

	<sect2>
	<title>recycle</title>

		<para>
		A recycle-bin like module. When used any unlink call
		will be intercepted and files moved to the recycle
		directory instead of being deleted. This gives the same 
		effect as the "Recycle Bin" on Windows computers.
		</para>
		
		<para>Supported options:
		<variablelist>
			<varlistentry>
			<term>recycle:repository</term>
			<listitem><para>Relative path of the directory where deleted files should be moved to</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:keeptree</term>
			<listitem><para>Specifies whether the directory structure should 
					be kept or if the files in the directory that is being 
					deleted should be kept seperately in the recycle bin.
			</para></listitem>
			</varlistentry>
			
			<varlistentry>
			<term>recycle:versions</term>
			<listitem><para>If this option is set, two files 
					with the same name that are deleted will both 
					be kept in the recycle bin. Newer deleted versions 
					of a file will be called "Copy #x of <replaceable>filename</replaceable>".</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:touch</term>
			<listitem><para>Specifies whether a file's access 
					date should be touched when the file is moved to 
			the recycle bin.</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:maxsize</term>
			<listitem><para>Files that are larger than the number 
					of bytes specified by this parameter will 
					not be put into the recycle bin.</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:exclude</term>
			<listitem><para>List of files that should not 
					be put into the recycle bin when deleted, but deleted 
					in the regular way.</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:exclude_dir</term>
			<listitem><para>Contains a list of directories. When files from 
					these directories are deleted, they are not put into the 
					recycle bin, but deleted in the regular way. 
			</para></listitem>
			</varlistentry>

			<varlistentry>
			<term>recycle:noversions</term>
			<listitem><para>Opposite of <parameter>recycle:versions</parameter>. If both options are specified, this one takes precedence.</para></listitem>
			</varlistentry>
		</variablelist>
		</para>

	</sect2>

	<sect2>
	<title>netatalk</title>

		<para>
		A netatalk module, that will ease co-existence of samba and
		netatalk file sharing services.
		</para>

		<para>Advantages compared to the old netatalk module:
		<itemizedlist>
		<listitem><para>it doesn't care about creating of .AppleDouble forks, just keeps them in sync</para></listitem>
		<listitem><para>if a share in &smb.conf; doesn't contain .AppleDouble item in hide or veto list, it will be added automatically</para></listitem>
		</itemizedlist>
		</para>

	</sect2>

</sect1>

<sect1>
<title>VFS modules available elsewhere</title>

<para>
This section contains a listing of various other VFS modules that 
have been posted but don't currently reside in the Samba CVS 
tree for one reason or another (e.g. it is easy for the maintainer 
to have his or her own CVS tree).
</para>

<para>
No statements about the stability or functionality of any module
should be implied due to its presence here.
</para>

	<sect2>
	<title>DatabaseFS</title>

		<para>
		URL: <ulink noescape="1" url="http://www.css.tayloru.edu/~elorimer/databasefs/index.php">http://www.css.tayloru.edu/~elorimer/databasefs/index.php</ulink>
		</para>

		<para>By <ulink url="mailto:elorimer@css.tayloru.edu">Eric Lorimer</ulink>.</para>

		<para>
		I have created a VFS module which implements a fairly complete read-only
		filesystem.  It presents information from a database as a filesystem in
		a modular and generic way to allow different databases to be used
		(originally designed for organizing MP3s under directories such as
		"Artists," "Song Keywords," etc... I have since applied it to a student
		roster database very easily).  The directory structure is stored in the
		database itself and the module makes no assumptions about the database
		structure beyond the table it requires to run.
		</para>

		<para>
		Any feedback would be appreciated: comments, suggestions, patches,
		etc...  If nothing else, hopefully it might prove useful for someone
		else who wishes to create a virtual filesystem.
		</para>

	</sect2>

	<sect2>
	<title>vscan</title>

	<para>URL: <ulink noescape="1" url="http://www.openantivirus.org/">http://www.openantivirus.org/</ulink></para>

		<para>
		samba-vscan is a proof-of-concept module for Samba, which
		uses the VFS (virtual file system) features of Samba 2.2.x/3.0
		alphaX. Of course, Samba has to be compiled with VFS support. 
		samba-vscan supports various virus scanners and is maintained 
		by Rainer Link.
		</para>

	</sect2>
</sect1>

</chapter>
