Last update 05-Nov-2004

MBSE BBS - Running DOS doors.


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.

One very important note: the virtual dos drive is now $MBSE_ROOT/var/dosemu/c Don't use another location or change the access rights, there will be several references from mbse to that and only that location for dos support. Choose another one and you are on your own!


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 copy this new file as virtual.conf in ~/etc/dosemu/. Then add the following line:
$_com1 = "virtual"
Note that in older dosemu versions you could use a commandline option to do this, but this isn't supported anymore since dosemu-1.2.x. The now also uses two configuration files.
Next we need to setup the C: drive. Do this as user mbse. First type umask 007, this sets the create mode for directories to 0770 and files to 0660 so that we create all files and directories read/write for all bbs users. This is very important! Type the following commands:
mbse@seaport:~$ 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, 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:



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/ 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 8ball
See also inside 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. In this example I will explain how to install the door 8ball. Start mbsedos and create a directory c:\doors\8ball. Unpack 8ball in that directory and run setup. Test the door with the command local. Now goto the directory c:\doors and create the file 8ball.bat. That file will be used to start the door. It will be called by c:\doors.bat with two parameters, the name of the door and the nodenumber.
C:\UTIL\X00 E B,0,57600
Finally we have to make a menu entry to start the door. The Opt. Data line is the command to start the door, the optional /N is replaced by the current nodenumber of the user. A second option may be used, novirtual, if that is present the will start dosemu without setting the comport in virtual mode. Use this if your door isn't a real door but a normal dos program.

door setup

Note that I use the Display lines to make the menu, there are only ansi screens for the top and common lines on the screen, see the second image how to build the whole doors menu.

doors menu


Netmail support

In the virtual c: drive you need some directories that point to several other mbse subdirectories. You may need at least three of them, one to put netmail in, one to put files in to send and one semafore directory to tell mbse there is something to send. For example like this:

ln -s /opt/mbse/var/msgs /opt/mbse/var/dosemu/c/msgs
ln -s /opt/mbse/var/boxes/node92_100_60 /opt/mbse/var/dosemu/c/outbox
ln -s /opt/mbse/var/sema /opt/mbse/var/dosemu/c/sema
In dos you now have:
In C:\MSGS doors may put *.msg netmails. File attaches won't work from these netmails because the netmails point to files with dosnames. (May be solved later). The script that calls the door, for example c:\doors\bre.bat must copy the file to send to the node outbound box. In the above example that would be copy to C:\OUTBOX. To create the semafore to tell mbse to scan add to the batfile (for example C:\DOORS\BRE.BAT the following two lines:
See also the F.A.Q. for some very usefull tips and tricks. Using the same method with symlinks, you can make all paths you need from the rest of mbse visible in dos. Use with care.


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/ is still there, but the file ~/bin/ is renamed to ~/bin/ So you should change all symlinks of your door names in ~/bin (or copies) to ~/bin/ You should not need to change anything else.


Currently there are some troubles with modem calls.

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