Chapter 20. Stackable VFS modules

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. -

Discussion

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. -

To use the VFS modules, create a share similar to the one below. The -important parameter is the vfs object parameter which must point to -the exact pathname of the shared library objects. For example, to log all access -to files and use a recycle bin: +important parameter is the vfs objects 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: -

+
 [audit]
-	comment = Audited /data directory
-    path = /data
-    vfs object = /path/to/audit.so /path/to/recycle.so
-    writeable = yes
-    browseable = yes
-

-
-The modules are used in the order they are specified.
+        comment = Audited /data directory
+        path = /data
+        vfs objects = audit recycle
+        writeable = yes
+        browseable = yes
+

+The modules are used in the order in which they are specified.

-Further documentation on writing VFS modules for Samba can be found in -the Samba Developers Guide. -

Included modules

audit

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

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

+[test]
+        comment = VFS TEST
+        path = /data
+        writeable = yes
+        browseable = yes
+        vfs objects = example:example1 example example:test
+		example1: parameter = 1
+		example:  parameter = 5
+		test:	  parameter = 7
+

Included modules

audit

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

extd_audit

connect/disconnect

directory opens/create/remove

file open/close/rename/unlink/chmod

extd_audit

This module is identical with the audit 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. + loglevel for this module is set in the smb.conf file.

The logging information that will be written to the smbd log file is controlled by the log level parameter in smb.conf. The following information will be recorded: -

Table 20.1. Extended Auditing Log Information

Log Level	Log Details - File and Directory Operations
0	Creation / Deletion
1	Create / Delete / Rename / Permission Changes
2	Create / Delete / Rename / Perm Change / Open / Close

fake_perms

Table 20.1. Extended Auditing Log Information

Log Level	Log Details - File and Directory Operations
0	Creation / Deletion
1	Create / Delete / Rename / Permission Changes
2	Create / Delete / Rename / Perm Change / Open / Close

fake_perms

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. -

recycle

A recycle-bin like module. When used any unlink call will be intercepted and files moved to the recycle directory instead of being deleted. -

Supported options: -

vfs_recycle_bin:repository: FIXME
vfs_recycle_bin:keeptree: FIXME
vfs_recycle_bin:versions: FIXME
vfs_recycle_bin:touch: FIXME
vfs_recycle_bin:maxsize: FIXME
vfs_recycle_bin:exclude: FIXME
vfs_recycle_bin:exclude_dir: FIXME
vfs_recycle_bin:noversions: FIXME

netatalk

Supported options: +

recycle:repository: FIXME
recycle:keeptree: FIXME
recycle:versions: FIXME
recycle:touch: FIXME
recycle:maxsize: FIXME
recycle:exclude: FIXME
recycle:exclude_dir: FIXME
recycle:noversions: FIXME

netatalk

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

Advantages compared to the old netatalk module: -

it doesn't care about creating of .AppleDouble forks, just keeps them in sync

if a share in smb.conf doesn't contain .AppleDouble item in hide or veto list, it will be added automatically

VFS modules available elsewhere

Advantages compared to the old netatalk module: +

it doesn't care about creating of .AppleDouble forks, just keeps them in sync

if a share in smb.conf doesn't contain .AppleDouble item in hide or veto list, it will be added automatically

VFS modules available elsewhere

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 @@ -63,7 +79,7 @@ to have his or her own CVS tree).

No statements about the stability or functionality of any module should be implied due to its presence here. -

DatabaseFS

URL: http://www.css.tayloru.edu/~elorimer/databasefs/index.php

By Eric Lorimer.

I have created a VFS module which implements a fairly complete read-only @@ -78,12 +94,12 @@ should be implied due to its presence here. 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. -

vscan

URL: http://www.openantivirus.org/

vscan

URL: http://www.openantivirus.org/

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 couse, Samba has to be compiled with VFS support. + alphaX. Of course, Samba has to be compiled with VFS support. samba-vscan supports various virus scanners and is maintained by Rainer Link. -

Common Errors

There must be some gotchas we should record here! Jelmer???

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