Xania MUD source

Found on @mattgodbolt's hard disk, and resurrected. Shows the code behind a UK-based Multi-User Dungeon that my university housemates and I ran, built and administrated in late 1990s.

Discord

We chat about the mud here. Feel free to drop in.

Building and running

If you want to build and run Xania locally, you'll need a modern Linux. We test it on Ubuntu 22.0.4 and Arch Linux.

It works within Docker including when hosted by Windows Subsystem for Linux. To learn more about this see the Docker-specific tutorial!

It has been reported to work on Fedora 34 too.

g++ and Other Essentials

Here are the Ubuntu steps for installing some prerequisites:

# Install gcc-12 and g++-12. Versions 13 and 11 work too!
$ sudo apt install build-essential manpages-dev software-properties-common
$ sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$ sudo apt update && sudo apt install gcc-12 g++-12

# Optional step: We recommend installing ninja-build as it speeds the builds up significantly.
$ sudo apt install ninja-build

# And you'll need the following...
$ sudo apt install git make curl

# Local builds autodetect g++-12 and use it for compilation, but fallback to g++-11.
# clang-15 works too (see later section).  If you want to build with a different compiler
# create a new cmake toolchain file e.g. "toolchain/mycompilers.cmake" and set the compiler
# variables in it. Then invoke make specifying the leading part of your toolchain name in 
# the TOOLCHAIN make variable e.g.
$ make TOOLCHAIN=mycompilers test

# Alternatively, if you know what you're doing you can invoke cmake directly and pass a custom 
# toolchain, (with -DCMAKE_TOOLCHAIN_FILE= or using the --toolchain switch (cmake >= 3.21)). 
# Take a look in the Makefile for how cmake gets invoked to generate the build currently.

CMake

You'll also need a recent version of cmake. At least version 3.19 is required, 3.21+ preferred. If you're running Ubuntu 18 or 20 you'll need to add the Kitware apt repository to your apt sources. On Ubuntu 22 or Arch Linux the cmake package is present in the main APT repository.

$ sudo apt install cmake

Build and Run

The build itself downloads and manages many other upstream dependencies such as conda and conan via the Makefile.

To build and run, type make:

$ make start
... lots of configuration nonsense here, downloads, cmake, and then compilation ...
All being well, telnet localhost 9000 to log in
$

The MUD is now running in the background, on port 9000. telnet localhost 9000 should get you the logon prompt. Create a character, and log in...and have fun!

If you want to build but not start it up, simply run make.

By default a debuggable unoptimized build is run. Use make BUILD_TYPE=release to build the optimized version.

Stopping and Restart the MUD

To stop Xania, run make stop. To restart, make restart.

Compiling with clang

You may be interested in compiling with clang, version 15 is known to work. You may also want to use clangd as an LSP for editors like neovim and the nvim-lspconfig plugin.

# First install the tools:
$ sudo apt install clang-15 clangd-15
$ update-alternatives --install /usr/bin/clangd clangd $(which clangd-15) 10
$ update-alternatives --install /usr/bin/clang clang $(which clang-15) 10
$ update-alternatives --install /usr/bin/clang++ clang++ $(which clang++-15)
$ update-alternatives --install /usr/bin/clang-tidy clang-tidy $(which clang-tidy-15)

Build by specifying the toolchain:

$ make TOOLCHAIN=clang-15

When building with clang, it's possible that you may run into compatibility problems with versions of libraries in your conan cache. The cache typically resides in ~/.conan. Removing the problematic libraries from the cache and re-running make is one solution. You can selectively nuke cached libraries, for example:

# Remove all versions of fmt from the cache
$ ./cmake-build-debug/.tools/conda-4.12.0/conan remove fmt/* -s -b -f
# Remove all cached libraries from the cache
$ ./cmake-build-debug/.tools/conda-4.12.0/conan remove "*" -s -b -f

Creating an immortal account

To administrate Xania from inside, you'll need a level 100 character. Create a character as above, then quit. Edit the player/Yourplayername file and edit the line with Levl 1 to be Levl 100. Then log back in and voila! You are an immortal!

Developing

The top-level Makefile is more of a convenience layer to set up a consistent environment. It delegates the actual building to a cmake-built system in one of the cmake-build-{type} directories (e.g. cmake-build-debug). A tiny amount of back-and-forth between the two systems ensures the cmake build system uses the various tools installed locally in .tools/ to do work (e.g. conan for C++ packages, clang-format for code formatting, etc). The top-level Makefile will configure cmake to use ninja if you have that installed, else it'll use make.

For day-to-day developing you can use your favourite IDE or editor (CLion, vs.code, vi, emacs). If your IDE supports CMake projects, then it might Just Work out of the box. CLion, for example, will open up and run the code from the IDE.

The mud happily runs without being installed, however it does rely on a few environment variables for configuration (see below).

There are two components, doorman and xania. The former is the TCP side of things, and unless you're changing how the MUD and the connection process communicate you can probably build and run doorman and then leave it running. xania is the MUD part, and so if you're debugging and building, that's probably the target to run.

We use clang-format to format all the code consistenly, and a .clang-format file is in the root. Again, most IDEs will pick up on this and just use it. Command-line users can run make reformat-code to reformat everything, or make check-format to just see if everything's formatted as it should be. At some point we'll make this part of the CI process.

Environment Variables

The mud processes use some environment variables for configuration. Out of the box, make start will set reasonable defaults for these. The default settings are stored in mud-settings-dev.sh, and make start will read this file.

If you are doing development and launching the processes from an IDE then you prefer to configure these settings separately. The project includes an example Visual Studio Code launch.json that sets these.

MUD_AREA_DIR: Static game database files.
MUD_DATA_DIR: The base directory of all runtime data. The mud uses these subdirectories:
- player/ (player character files)
- gods/ (configuration for deities)
- system/ (other player generated data e.g. ban lists and bug lists)
- log/ (the mud processes are unaware of this as log output is redirected from to stdout & stderr)
MUD_HTML_DIR: Static and dynamically generated HTML.
MUD_PORT: The TCP port doorman listens on for telnet connections. Default: 9000.

If you are running either process directly from a shell rather than using make start or a launch target in your IDE, there is also a helper script mud-settings-dev.sh. Source this file from one of your shells then run the process e.g. after running the build:

$ . mud-settings-dev.sh
$ ./install/bin/doorman

Tests

There are some very early tests. To run the tests, use make test, or run them from your IDE.

Debugging Xania in GDB

There's more than one way to do this, and one way is: after building Xania you can run it like so (use of gdb is optional):

$ gdb install/bin/xania
(gdb) r   # to run

You can also attach to the running process using gdb -p.

If you're relying on the default make targets to build & start things, the reboot command from within the MUD will not restart the processes.

A solution is to not run make start at all, but instead, execute ./install/bin/doorman and the xania executable directly in another terminal as described above.

For neovim users, the nvim-gdb plugin works well.

Going "live"

When the MUD is actually deployed, we make install to get a built setup with areas and binaries etc. That's tar'd up and copied to a host to run. player files and whatnot are managed separately. If you're curious how we're sketching out ideas for the deployment, check out the infra/ directory. It's a bit wild in there right now though.

License

See the LICENSE file for more details, but this code is built on and extends code from Rom2.4 code.

Xania's log on banner contains a lot of the required info. As you may not wish to log in, it is:

.   .... NO! ...                  ... MNO! ...
.... MNO!! ...................... MNNOO! ..    /    \    /    \
.... MMNO! ......................... MNNOO!!   \     \  /     /
.. MNOONNOO!   MMMMMMMMMMPPPOII!   MNNO!!!!     \     \/     /
.. !O! NNO! MMMMMMMMMMMMMPPPOOOII!! NO! ...      \          /  A N I A
  ...... ! MMMMMMMMMMMMMPPPPOOOOIII! ! ...       /    /\    \
 ........ MMMMMMMMMMMMPPPPPOOOOOOII!! .....     /    /  \    \
 ........ MMMMMOOOOOOPPPPPPPPOOOOMII! ...      /    /    \    \
  ....... MMMMM..    OPPMMP    .,OMI! ....     \   /      \   /
   ...... MMMM::   o.,OPMP,.o   ::I!! ... 
       .... NNM:::.,,OOPM!P,.::::!! ....    ...where it is recognised that 
       .. MMNNNNNOOOOPMO!!IIPPO!!O! .....   shaking hands with Death brings
       ... MMMMMNNNNOO:!!:!!IPPPPOO! ....  longevity and considerable kudos.
         .. MMMMMNNOOMMNNIIIPPPOO!! ......
        ...... MMMONNMMNNNIIIOO!..........
     ....... MN MOMMMNNNIIIIIO! OO .......... DikuMUD by Hans Staerfeldt
  ......... MNO! IiiiiiiiiiiiI OOOO ......... Katja Nyboe, Tom Madsen, Michael
 ..... NNN.MNO! . O!!!!!!!!!O . OONO NO! .... Seifert, and Sebastian Hammer.
 .... MNNNNNO! ...OOOOOOOOOOO .  MMNNON!..... Based on MERC 2.2 code
 ...... MNNNNO! .. PPPPPPPPP .. MMNON!....... by Hatchet, Furey, and Kahn,
    ...... OO! ................. ON! .......  ROM 2.4 (C) 1993-96 Russ Taylor
       ................................       MUDdled by the Xanian Immortals

I (@mattgodbolt) believe the code is free to open source, but of course if you have any issues don't hesitate to contact me.

Thanks to

The Xania implementors were avid players of MadROM, and were inspired to get the ROM code and start hacking on their own MUD. In particular thanks to Etaine, Ozymandius, Neuromancer, Amiga and Crash. Sorry if we forgot someone!

In the MUD itself, the thanks read:

Xania was created by The Moog, Death, Faramir, Rohan  and Wandera,
five bold Gods who saw fit to create a new world where
peace and happiness would reign. Sadly, (due to  sheer incompetence)
they made a nasty mistake somewhere along the line, and an infestation
of evil spread chaotically throughout  the realm. Thus, this place is
no longer safe and it is up to you, bold adventurer, to face up to the
prospect of meeting an untimely demise!

A special thank you to the original immortals and heroes who contributed
to Xania's success, you can see their names using the 'wizlist' command.

And it goes without saying, Xania would have been nothing without the base
code and areas that shipped with Rivers of Mud (ROM), its sister mud, MadROM,
and before that, DikuMUD and MERC. We owe a debt of gratitude to the original
developers and zonesmiths.

mattgodbolt / xania