Last update 09-Aug-2004

MBSE BBS - Running DOS doors.

Introduction

Running DOS doors is possible on systems that can run dosemu. The latest versions of dosemu don't need to be started suid root or started using sudo, it can run as the user that is logged in the bbs. Since that is possible, a new location for the virtual C: drive is now being used withing the $MBSE_ROOT file structure. This virtual C: drive is owned by the group bbs. The basic ideas how doors should be run written by Redy Rodriguez are still valid, but some scripts are changed and some dosemu files must be copied into the mbse directory tree.

 

Installing dosemu

Some distributions have good dosemu packages, others don't. You need a dosemu that can be used in a systemwide multiuser setup. The bad packages want to have the dos drive in each users home directory, this is not what we want for doors. If you don't have a good dosemu you have to compile your own. This is not too complicated. First download the source from dosemu. You don't need the freedos-bin source if you are going to use ms-dos or pc-dos. Unpack the source in some directory of your choice and compile the sources:

mbse@seaport$ tar xfvz dosemu-1.2.2.tgz
mbse@seaport$ cd dosemu-1.2.2
mbse@seaport:~/dosemu-1.2.2$ ./configure --prefix=/usr --sysconfdir=/etc/dosemu --with-x
mbse@seaport:~/dosemu-1.2.2$ make
Note that the --with-x is not needed for running doors, but it might be handy that you can use dosemu as user mbse in X to do maintenance on your doors.
Then as root do:
root@seaport:~/dosemu-1.2.2# make install

 

Setup dosemu in mbse

First copy /etc/dosemu/dosemu.conf into ~/etc/dosmeu. Then edit ~/etc/dosemu/dosemu.conf so that we have a version for mbse users. Set the following settings in that file:

$_hdimage = "/opt/mbse/var/dosemu/c"
$_floppy_a = ""
$_xms = (1024)
$_ems = (2048)
$_dpmi = (0x1000)
$_layout = "us"
Next we need to setup the C: drive. Do this as user mbse. First type umask 007, this sets the create mode for directories to 0770 and files to 0660 so that we create all files and directories read/write for all bbs users. This is very important! Type the following commands: 
mbse@seaport:~$ umask 007
mbse@seaport:~$ cd var/dosemu/c
mbse@seaport:~/var/dosemu/c$ mkdir dos dosemu temp util doors
Now we must install dos. If you use ms-dos then in ~/var/dosemu/c copy the ms-dos files command.com, io.sys and msdos.sys. In ~/var/dosemu/c/dos copy all ms-dos commands. Next install the dosemu utilities, copy these from /usr/share/dosemu/freedos/dosemu to ~/var/dosemu/c/dosemu. Now there is a empty ~/var/dosemu/c/util, copy some utilities here such as your favourite dos editor, zip and unzip etc.
Next we must create config.sys and autoexec.bat. These files must be dos crlf formatted. You can do that with the joe editor, for example joe -crlf config.sys. Examples:
config.sys
BUFFERS = 20
DEVICE=C:\DOS\SETVER.EXE
SET TEMP=C:\TEMP
DOS=HIGH,UMB
FILES=50
autoexec.bat
@ECHO OFF
PROMPT $P$G
PATH C:\DOSEMU;C:\DOS;C:\UTIL;
SET TEMP=C:\TEMP
Lh C:\DOS\DOSKEY /INSERT
Lh C:\DOS\SHARE
Now we are ready to try it, type mbsedos and the dos emulator should start. You can leave dosemu with the command exitemu.

 

Installing a door

All doors are started using the script ~/bin/rundoor.sh. This script is never started directly, you should make a copy of that with the name of the door, but the best solution is to make a symlink with the name of the door. For example:

mbse@seaport$ cd ~/bin
mbse@seaport:~bin$ ln -s rundoor.sh ilord
See also inside rundoor.sh for the instructions. This file does several things, first it prepares the users home directory with the dosemu environment so that dosemu will run for the user. Then it creates a node directory in the dos C: drive and copies the door dropfiles into that node directory. Finally it starts dosemu in virtual comport mode and inserts the commands in dos to start the door.
But before we can run the door, the door itself must be installed in the dos partition.

 

What if I don't upgrade

That's your choice, but for a while the old method starting dosemu via sudo is still supported. The file ~/bin/bbsdoor.sh is still there, but the file ~/bin/rundoor.sh is renamed to ~/bin/runvirtual.sh. So you should change all symlinks of your door names in ~/bin (or copies) to ~/bin/runvirtual.sh. You should not need to change anything else.

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