ENiGMA½ has many ways to add doors to your system. In addition to the many built in door server modules, local doors are of course also supported using the ! The `abracadabra` module!
The `abracadabra` module provides a generic and flexible solution for many door types. Through this module you can execute native processes & scripts directly, and perform I/O through standard I/O (stdio) or a temporary TCP server.
*`io`: Where to process I/O. Can be `stdio` or `socket`. When using `stdio`, I/O is input/output from stdin/stdout. When using `socket` a temporary socket server is spawned that can be connected to. The server listens on localhost on `{srvPort}` (see below under Argument Variables).
[DOSEMU](http://www.dosemu.org/) can provide a good solution for running legacy DOS doors when running on Linux systems. For this, we will create a virtual serial port (COM1) that communicates via stdio.
As an example, here are the steps for setting up Pimp Wars:
First, create a `dosemu.conf` file with the following contents:
```
$_cpu = "80486"
$_cpu_emu = "vm86"
$_external_char_set = "utf8"
$_internal_char_set = "cp437"
$_term_updfreq = (8)
$_layout = "us"
$_rawkeyboard = (0)
$_com1 = "virtual"
```
The line `$_com1 = "virtual"` tells DOSEMU to use `stdio` as a virtual serial port on COM1.
Next, we create a virtual **X** drive for Pimp Wars to live such as `/enigma-bbs/DOS/X/PW` and map it with a custom `autoexec.bat` file within DOSEMU:
```
@echo off
path d:\bin;d:\gnu;d:\dosemu
set TEMP=c:\tmp
prompt $P$G
REM http://www.pcmicro.com/bnu/
C:\BNU\BNU.COM /L0:57600,8N1 /F
lredir.com x: linux\fs\enigma-bbs\DOS\X
unix -e
```
Note that we also have the [BNU](http://www.pcmicro.com/bnu/) FOSSIL driver installed at `C:\BNU\\`. Another option would be to install this to X: somewhere as well.
Finally, let's create a `menu.hjson` entry to launch the game:
[QEMU](http://wiki.qemu.org/Main_Page) provides a robust, cross platform solution for launching doors under many platforms (likely anwywhere Node.js is supported and ENiGMA½ can run). Note however that there is an important and major caveat: **Multiple instances of a particular door/OS image should not be run at once!** Being more flexible means being a bit more complex. Let's look at an example for running L.O.R.D. under a UNIX like system such as Linux or FreeBSD.
Basically we'll be creating a bootstrap shell script that generates a temporary node specific `go.bat` to launch our door. This will be called from `autoexec.bat` within our QEMU FreeDOS partition.
[FreeDOS](http://www.freedos.org/) is a free mostly MS-DOS compatible DOS package that works well for running 16bit doors. Follow the [QEMU/FreeDOS](https://en.wikibooks.org/wiki/QEMU/FreeDOS) guide for creating an `freedos_c.img`. This will contain FreeDOS itself and installed BBS doors.
After this is complete, copy LORD to C:\DOORS\LORD within FreeDOS. An easy way to tranfer files from host to DOS is to use QEMU's vfat as a drive. For example:
Note the `qemu-system-i386` line. We're telling QEMU to launch and use localtime for the clock, create a character device that connects to our temporary server port on localhost and map that to a serial device. The `-hdb` entry will represent the D: drive where our drop file is generated, while `-hdc` is the path that `GO.BAT` is generated in (`E:\GO.BAT`). Finally we specify `-nographic` to run headless.
As of this writing `DOOR32.SYS` style socket descriptor sharing is **not** supported. Workarounds include using the Telnet Bridge (`telnet_bridge` module) to hook up to local Telnet-accessible door servers such as [NET2BBS](http://pcmicro.com/netfoss/guide/net2bbs.html).
