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[AROS.git] / workbench / network / smbfs / documentation / smbfs.doc

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', 'AmiTCP
Genesis' or 'Roadshow' 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,TZ=TIMEZONEOFFSET/N/K,
   DST=DSTOFFSET/N/K,TRANSLATE=TRANSLATIONFILE/K,SERVICE/A

The individual options serve the following purposes:

   DOMAIN=WORKGROUP/K

      You must specify the name of the work group or domain which 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.

      The authentication process only works if the machine you are connecting
      to knows about the user name and password you want to use. As of this
      writing, smbfs cannot be used for authenticating against a password
      server that is not the same machine as the one from which you wish to
      import a share.

   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 tagged 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.

   TZ=TIMEZONEOFFSET/N/K

      By default the file system will use the current Locale settings to
      translate between the local time and the time used by the SMB
      server. For some configurations, however, this is impractical since
      the server's time zone is not configured properly. For these
      rare cases you may want to hard code a certain time zone offset
      using the 'TIMEZONEOFFSET' options. The number you provide must
      be the number of minutes to add to the local time in order to
      translate it into the corresponding GMT value. For example, in
      central Europe using CET, you would use "TZ=-60" since CET is
      one hour ahead of GMT.

   DST=DSTOFFSET/N/K

      This option can be used to adjust the file date stamps to take
      local daylight savings time into account. The number to specify here
      is by how many minutes local time has been moved ahead, which is
      typically 60. Note that smbfs does not know when daylight savings
      time begins and ends. It is up to you to select the correct value
      when appropriate.

   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.

      For now no special characters are allowed in the name of the service
      as no translation is performed like would be the case for file names
      on the volume.

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 are 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:

   obarthel -at- gmx -dot- net

Or, alternatively, you might want to contact me via my postal address:

   Olaf Barthel
   Gneisenaustr. 43
   D-31275 Lehrte
   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. If possible, use the
facilities for bug reporting and tracking on the sourceforge.net web site
at <http://sourceforge.net/projects/amiga-smbfs>, which is the new home for
this file system.


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 Roadshow SDK
providing for the TCP/IP stack API header files.