Scripts & Native Binaries

Scripts & Native Binaries (abracadabra)

The abracadabra module provides a generic solution for launching any local process as a door: native terminal applications, shell scripts, Python scripts, and more. Any process that communicates over stdio works. I/O is bridged through standard I/O (stdio) or a temporary TCP socket server.

Note

For DOS-specific setups using DOSEMU or QEMU, see External DOS Emulators. For zero-dependency DOS emulation, see Native v86 Emulation.

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Configuration

The abracadabra config block supports the following fields:

Item	Required	Description
name	Yes	Used as a key for tracking the number of clients using this door.
dropFileType	No	Type of drop file to generate. See Drop File Types. Can be omitted or none.
cmd	Yes	Path to the executable to launch.
args	No	Array of arguments to pass to cmd. See Argument Variables below.
preCmd	No	Path to a pre-command executable or script. Executes before cmd.
preCmdArgs	No	Arguments to pass to preCmd. See Argument Variables below.
cwd	No	Working directory for cmd. Defaults to the directory containing cmd.
env	No	Environment variables as a map: { SOME_VAR: "value" }
nodeMax	No	Max concurrent sessions for this door. Uses name as the tracking key.
tooManyArt	No	Art spec to display when nodeMax is exceeded.
io	No	I/O mode: stdio (default) or socket. When socket, ENiGMA½ spawns a temporary TCP server on {srvPort} that the door process connects back to.
commType	No	What the drop file tells the door it is talking to: local, serial, or socket. Defaults to socket when io: socket, otherwise local. See Comm Type below.
encoding	No	The door process’s text encoding. Defaults to cp437. Linux-native binaries often use utf8.

Comm Type

io says how ENiGMA½ talks to the process it spawns; commType says how the door talks to the caller. They are the same thing only when the process ENiGMA½ spawns is the door, which is why the default is derived from io:

commType	Reported as	Use when
local (default)	DOOR32.SYS comm type 0, DOOR.SYS COM0:, DORINFO 0	The door reads stdin and writes stdout. This covers io: stdio, which is nearly every native or scripted door.
serial	DOOR32.SYS comm type 1, DOOR.SYS COM1:, DORINFO COM1	An emulator sits between ENiGMA½ and the door and presents it a COM port — QEMU bridging {srvPort} onto isa-serial, for example.
socket	DOOR32.SYS comm type 2, DOOR.SYS COM1:, DORINFO COM1	Descriptor sharing by way of bivrost!.

Caution

Setting commType: socket does not give the door a socket. ENiGMA½ shares a socket server, not a descriptor, so DOOR32.SYS line 2 is written as -1 and bivrost! replaces both lines with the real handle. A door handed 2 and -1 with nothing in between is entitled to refuse to start, and some do.

Doors that ignore these fields entirely — most DOS-era games under an emulator — are unaffected by any of this.

Argument Variables

The following variables can be used in args and preCmdArgs:

Variable	Description	Example
{node}	Current node number	1
{dropFile}	Drop file filename only	DOOR.SYS
{dropFilePath}	Full path to the generated drop file	/home/enigma/drop/node1/DOOR.SYS
{dropFileDir}	Full path to the drop file directory	/home/enigma/drop/node1/
{userAreaDir}	User-specific save directory	/home/enigma/drop/node1/NuSkooler/lord/
{userId}	Current user ID	42
{userName}	Sanitized username (safe for filenames)	nuskooler
{userNameRaw}	Raw username (may not be filename-safe)	\/\/izard
{srvPort}	Temporary TCP server port (when io: socket)	1234
{cwd}	Working directory	/home/enigma/doors/foo/
{termHeight}	Terminal height	25
{termWidth}	Terminal width	80

args: [
    "-D", "{dropFilePath}",
    "-N", "{node}",
    "-U", "{userId}"
]

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Examples

Shell Script Door (stdio)

A simple wrapper script that launches a native binary:

doorMyGame: {
    desc: My Door Game
    module: abracadabra
    config: {
        name: MyGame
        dropFileType: DOOR
        cmd: /home/enigma/doors/mygame/launch.sh
        args: [ "{node}", "{dropFilePath}" ]
        nodeMax: 4
        tooManyArt: DOORMANY
        io: stdio
    }
}

Python Script Door (stdio)

doorPythonGame: {
    desc: Python Door
    module: abracadabra
    config: {
        name: PythonGame
        dropFileType: DORINFO
        cmd: /usr/bin/python3
        args: [ "/home/enigma/doors/pydoor/main.py", "{node}", "{dropFilePath}" ]
        encoding: utf8
        nodeMax: 8
        io: stdio
    }
}

Socket-Based Door

Some doors require a socket connection rather than stdio. ENiGMA½ starts a temporary TCP server and passes the port to your script:

doorSocketGame: {
    desc: Socket Door
    module: abracadabra
    config: {
        name: SocketGame
        dropFileType: DOOR
        cmd: /home/enigma/doors/socketgame/launch.sh
        args: [ "{node}", "{dropFile}", "{srvPort}" ]
        nodeMax: 1
        io: socket
    }
}

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DOOR32.SYS Socket Descriptor Sharing

Due to Node.js limitations, ENiGMA½ does not directly support DOOR32.SYS-style socket descriptor sharing. However, bivrost! bridges this gap. bivrost! is available for Windows and Linux x86/x86_64 (and buildable from Rust on other platforms).

doorWithBivrost: {
    desc: Bivrost Example
    module: abracadabra
    config: {
        name: BivrostExample
        dropFileType: DOOR32
        cmd: /home/enigma/utils/bivrost
        args: [
            "--port", "{srvPort}",
            "--dropfile", "{dropFilePath}",
            "--out", "/home/enigma/doors/jezebel",
            "/home/enigma/doors/jezebel/door.exe /home/enigma/doors/jezebel/door32.sys"
        ]
        nodeMax: 1
        tooManyArt: DOORMANY
        io: socket
    }
}

See the bivrost! documentation for details. Pre-built binaries are also available via Phenom Productions on various boards.

Alternative workarounds: Telnet Bridge, or NET2BBS.

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See Also

• Local Doors
• External DOS Emulators
• Native v86 Emulation
• Telnet Bridge