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A SMB file system wrapper for AmigaOS, using the AmiTCP V3 API
==============================================================
1. What is it?
This document briefly describes the SMBFS program, which implements an SMB
file system for AmigaOS. This file system can be used to access files made
available by file servers which implement the SMB protocol, such as 'Microsoft
Windows' or any other platform which supports the free 'Samba' product. These
files can be accessed using shell commands such as 'List', the Workbench or
utilities such as 'Directory Opus' as if the file server were a local disk
drive.
2. What do you need to get started?
You need a TCP/IP stack that supports the AmiTCP V3 API, such as 'Miami', the
original free 'AmiTCP 3.0' release, 'AmiTCP 4.x', 'Miami Deluxe' or 'AmiTCP
Genesis' and the obligatory networking gear. All these items need to be in
good shape and properly configured.
Most important, you need a computer which exports file sharing services using
the SMB protocol.
It often helps to have 'Samba' installed on your Amiga, too, as this can aid
in tracking down bugs and obtaining information which SMBFS cannot obtain all
by itself.
Last but not least, you need to be proficient in configuring and using the
TCP/IP stack; networking knowledge is definitely assumed.
SMBFS requires AmigaOS 2.04 or higher to work.
3. Preparations
You need to know which computer's files you want to share using the SMBFS file
system. That computer must be known by name, it is not sufficient just to know
its IP address. If you know the IP address but cannot refer to the host by its
name then SMBFS will not work. In that case, make sure that you add a host
name entry referring to the IP address to your TCP/IP stack's host database
(e.g. the "AmiTCP:bin/hosts" file or the corresponding page in the stack's
configuration user interface).
The name of the computer to connect to must not be too long. If it is longer
than 16 characters, SMBFS will not work properly.
You need to know which service you want to connect to on the target computer.
You can find out which services are available on a certain computer by using
the Samba 'smbclient' program. For example, if you were to query the services
offered by a machine called 'sourcery' you could enter the following:
samba:bin/smbclient -L sourcery
And you might get the following information:
added interface ip=192.168.0.1 bcast=192.168.0.255 nmask=255.255.255.0
Password: Domain=[ARBEITSGRUPPE] OS=[AmigaOS] Server=[Samba 2.0.7]
Sharename Type Comment
--------- ---- -------
All Disk All volumes in the system
IPC$ IPC IPC Service (Amiga 3000UX)
olsen Disk Home Directories
Server Comment
--------- -------
SOURCERY Amiga 3000UX
Workgroup Master
--------- -------
ARBEITSGRUPPE SOURCERY
The share name to connect to would be "ALL" in this case.
You need to know which login name and which password are required to connect
to the shared resource, and you need to know the name of the workgroup or
domain the file server is a member of.
4. Starting and stopping the file system
SMBFS is an uncommon kind of file system in that you do not use the 'Mount'
command to mount it. In fact, SMBFS is a shell program which can be launched
from the shell, using command line parameters to tell it which resources
should be used. But you can also start it from Workbench: in this case you
would have to put the program's command line options into icon tool types.
By now you should have assembled the following information:
- Name of the computer to connect to; this would be the
file server
- Name of the shared SMB resource to connect to
- Login name and password
That's basically everything you need to know to continue -- unless something
goes wrong, but more on that lateron.
Now you can start the file system. For example, to connect to the file server
called 'sourcery' and the shared 'all' resource it exports, with that computer
being a member of the workgroup 'Arbeitsgruppe', using the login name
'PCGuest' and not providing any password you would enter the following:
Run >NIL: SMBFS Workgroup=Arbeitsgruppe User=PCGuest Service=//sourcery/all
This would cause a new device by the name of "SMBFS:" to be mounted, showing
all files and directories the 'sourcery' server makes available for sharing.
How do you 'unmount' the file system? That's very easy, just check the output
of the 'Status' shell command. You might get the following output:
Process 1: Loaded as command: TURBOTEXT
Process 2: Loaded as command: Work:Tools/Blowup
Process 3: Loaded as command: Work:Tools/Sashimi
Process 4: Loaded as command: Work:CyberTools/CyberGuard
Process 5: Loaded as command: Work:Tools/OpenDevicePatch
Process 6: Loaded as command: CED
Process 7: Loaded as command: Workbench
Process 8: Loaded as command: Status
Process 9: No command loaded
Process 10: Loaded as command: SMBFS '//sourcery/all'
Look at the last line describing process number 10: it shows the name of the
file system program SMBFS and the name of the SMB share it is connected to. To
stop this file system and effectively unmount it, use the shell 'Break'
command; in this case you would enter "Break 10" to stop the file system. Note
that the program may not terminate immediately; it may have to wait until the
last client has released all resources referring to the file system. You may
have to send more than one "Break" command to stop the program.
5. Startup options
The SMBFS program supports a number of command line options, as will be
described below. The command template looks like this:
DOMAIN=WORKGROUP/K,USER=USERNAME/K,PASSWORD/K,CHANGECASE/S,
CASE=CASESENSITIVE/S,OMITHIDDEN/S,QUIET/S,CLIENT=CLIENTNAME/K,
SERVER=SERVERNAME/K,DEVICE=DEVICENAME/K,VOLUME=VOLUMENAME/K,
CACHE=CACHESIZE/N/K,DEBUGLEVEL=DEBUG/N/K,TRANSLATE=TRANSLATIONFILE/K,
SERVICE/A
The individual options serve the following purposes:
DOMAIN=WORKGROUP/K
You must specify the name of the workgroup or domain the file server to
connect to is a member of. The name of this workgroup or domain must not
be longer than 16 characters. The name you provide will be translated to
all upper case characters.
You need not provide for a work group or domain name on the command line.
Alternatively, you may configure an environment variable whose contents
will be used instead. The variable could be set up like this:
SetEnv smbfs_workgroup <name of domain or workgroup>
Copy ENV:smbfs_workgroup ENVARC:
You may also use the 'smbfs_domain' environment varilable in place of the
'smbfs_workgroup' variable. The two are aliases for one another, but
smbfs will read only one of the two.
USER=USERNAME/K
To connect to an SMB share you must authenticate yourself by providing a
user name. With this program the user name is optional; if you do not
provide one, SMBFS will use the default, which is "GUEST". The user name
must not be longer than 64 characters. The name you provide will be
translated to all upper case characters.
You need not provide for a user name on the command line. Alternatively,
you may configure an environment variable whose contents will be used
instead. The variable could be set up like this:
SetEnv smbfs_username <your user name>
Copy ENV:smbfs_username ENVARC:
You may also use the 'smbfs_user' environment varilable in place of the
'smbfs_username' variable. The two are aliases for one another, but
smbfs will read only one of the two.
PASSWORD/K
As part of the authentication process required to make the connection to
an SMB share, you must provide for a user name and a password. The
password is optional; if you do not provide one, an empty password will
be transmitted. The password must not be longer than 64 characters.
You need not provide for a password on the command line. Alternatively,
you may configure an environment variable whose contents will be used
instead. The variable could be set up like this:
SetEnv smbfs_password <your password>
Copy ENV:smbfs_password ENVARC:
Keep in mind that passwords like these really should not be exposed by
storing them in environment variables. But then the protocol smbfs uses
is almost as insecure as it gets anyway.
CHANGECASE/S
By default the password will not be changed to all upper case characters.
If this is required, you should either provide the password in this
form or resort to this option, which will cause it to be translated
to all upper case characters.
CASE=CASESENSITIVE/S
Some file servers treat file and directory names differently which
differ only in whether they are written using upper/lower case
characters. For these servers you should activate the CASESENSITIVE
switch to treat those files properly. There is a catch though: the
AmigaDOS file naming scheme does not follow this model and you may
run into problems when you are trying to use it. By default, the
file system does not treat file and directory names differently
which only differ with respect to the case of letters.
OMITHIDDEN/S
When requesting a directory listing, the server may return some files
and directories tagges as being hidden. By default this file system
will report these 'hidden' entries anyway, but you can request
specifically that what is intended to be hidden should be omitted
from directory listings, too. Note that even though a file may be
hidden you should still be able to open and examine it.
QUIET/S
When started from Shell, SMBFS will print a message as soon as the
connection to the file server has been established. If you do not
want to see that message displayed, use the QUIET parameter. Also,
no such message will appear if the program has been started to run
in the background.
CLIENT=CLIENTNAME/K
SMBFS will attempt to connect to the file server by providing the name
of the computer you connect from. In some cases this may be undesirable
as the computer's name differs from what the file server expects. You
can use the CLIENT parameter to tell SMBFS under which name it should
announce itself to the server. This parameter is optional and will be
translated to all upper case characters; it cannot be longer than 16
characters.
SERVER=SERVERNAME/K
SMBFS will attempt to connect to the file server by providing the name
you specified using the SERVICE command line parameter. In some cases
this may be undesirable as the server's name differs from what you
specified as the share name. You can use the SERVER parameter to tell
SMBFS under which name it should contact the server. This parameter is
optional and will be translated to all upper case characters; it cannot
be longer than 16 characters.
DEVICE=DEVICENAME/K
VOLUME=VOLUMENAME/K
The SMBFS program can announce itself as an AmigaDOS file system by
using one of two different methods.
The first method involves announcing itself only as a file system
device. This should be sufficient in most cases but has a drawback in
that the device will not be usable from Workbench since the file system
will not appear as a disk icon. You tell SMBFS to use a specific device
name by using the DEVICE command line parameter, e.g. "DEVICE=SMBFS:".
Note that device names must be unique, i.e. there must be no other
device by the same name in the system; SMBFS will report an error and
exit if it finds one.
The second method involves announcing itself as a volume. This has the
benefit of making the file system usable from Workbench since a disk
icon will appear for it. You tell SMBFS to use a specific volume name by
using the VOLUME command line parameter, e.g. "VOLUME=Sourcery:".
Both methods have advantages and drawbacks. The drawback of the VOLUME
method is that it may deadlock the native Amiga Samba port as soon as
the file system is mounted. The drawback of the DEVICE method is that
the file system will not be usable from Workbench.
If you wish, you can combine both methods; this is the approach most
other file systems use. And in fact, when you tell SMBFS to add a
volume it will also add a device to go along with it.
The VOLUME and DEVICE keywords are optional; if you omit both, SMBFS
will pretend that you had used the "DEVICE=SMBFS:" parameter.
CACHE=CACHESIZE/N/K
The file system attempts to optimize accesses to the file server when
directory contents are being scanned. These contents are buffered in
a directory cache which by default will hold 170 entries. Since each
entry will require about 255 bytes of storage, the entire 170 entry
cache will occupy more than 40K bytes of memory. You may want to change
this requirement, by making the cache smaller or larger using the
CACHESIZE parameter. The size of the directory cache cannot be smaller
than 10 entries.
DEBUGLEVEL=DEBUG/N/K
By default SMBFS operates in silent mode. It does not report what it is
doing, it just tries to respond to file system requests. To obtain
debugging output you may want to use the DEBUG option and specify a
debug level greater than 0. The larger the number you specify the more
debugging output will be created. Note that all debugging output will be
produced using the operating system's debug output functionality which
requires that you have a capturing program like 'Sashimi' running in the
background.
TRANSLATE=TRANSLATIONFILE/K
The Amiga and the file server SMBFS connects to may not share the same
character set. International characters used in file names on either
side may not come out correctly on the other side. To remedy this
problem, you can resort to file name translation. How the individual
names are to be translated is determined by the contents of a file
name translation table file such as the ones that ship with Workbench
in the "L:FileSystem_Trans" drawer. The first 256 bytes of each such
file must consist of the mapping of Amiga characters to the different
character set, and the second 256 characters must describe a mapping
back from the different character set to the Amiga. In most cases the
"L:FileSystem_Trans/INTL.crossdos" translation table file should be
sufficient. To specify which file contains the translation tables to
use you would use the TRANSLATIONFILE parameter.
SERVICE/A
This is the last parameter to be specified on the command line. It
should refer to the file server you want to connect to and the resource
it exports, e.g. a file system. This parameter must start with two
slashes which must be immediately followed by the file server's name,
which must be followed by the resource to connect to.
The same parameters are also used when starting SMBFS from Workbench. SMBFS
will examine its icon tool types and use these in place of the shell command
line.
6. Known problems
The design of smbfs follows the original file system concept behind the
code which the 'Sharity-Light' file system is based upon. And that is a
Unix file system which differs from Amiga specific file systems in many
ways which can lead to problems which should be discussed briefly below:
- Single threaded design
This means that it is not possible for several programs to fairly
share the use of the file system. For example, a program that posts
a long read request can tie up the file system almost exclusively
for itself, and while it is busy all other clients will have to
wait. Same goes for directory scanning.
- Poor scalability
This is associated with the single threaded design. When several
programs are accessing the file system at the same time, overhead
and unfair sharing of resources will drastically reduce the
performance of the file system.
- Separation of file data and metadata
This means that the core of the file system treats the contents of
a directory and the data attached to each file inside that
directory as something different. This is a common concept with
Unix file systems, but it is very different with Amiga file systems.
In smbfs this data separation can cause problems when deleting
files from a directory while that directory is being scanned,
such as how this is being done by the 'Delete' shell command. The
effects of these problems are that a directory may not be deleted
even though it is empty or that for the same directory the same
file may be reported twice in the listing.
While there are no easy solutions for any of these problems, it does not
mean that smbfs is unusable. You just have to be more careful when you
use the file system. For example, if a directory's contents cannot be
deleted due to one of the problems mentioned above, you might want to
retry later.
It should be noted that the problems described above are not inherent
to the original file system design. It's just that transferring that
design to an Amiga file system created the problems.
7. Credits
This file system is based upon prior work by Paal-Kr. Engstad, Volker
Lendecke, Mark A. Shand, Donald J. Becker, Rick Sladkey, Fred N. van Kempen,
Eric Kasten and Rudolf Koenig. It is a direct descendant of the
'Sharity-Light' file system written by Christian Starkjohann.
The password encryption code was lifted from the Samba package. It was
written by Andrew Tridgell and the Samba Team.
8. Author
The 'Sharity-Light' source code was adapted and wrapped into an AmigaOS layer
by Olaf `Olsen' Barthel. If you wish to contact me, please send e-mail to the
following address:
olsen@sourcery.han.de
Or, alternatively, you might want to contact me via my postal address:
Olaf Barthel
Brabeckstr. 35
D-30559 Hannover
Federal Republic of Germany
If you want to submit a bug report or an enhancement request, please enclose
sufficient information to allow me to make sense of the problem. That includes
debugging logs produced using the DEBUG option.
9. Source code
SMBFS is distributed under the terms of the GNU General Public License
(version 2). The source code should have accompanied this program; if it
hasn't, please contact the author for a copy.
The program was compiled using the SAS/C 6.58 compiler, with the Miami SDK
providing for the TCP/IP stack API header files.