# xrxs `xrxs` is an experimental game server using the Plan 9 protocol `9p`. The client is a specialized [uxn](https://wiki.xxiivv.com/site/uxn.html) ROM that can load other ROMs over the network via the `9p` service. ## design This is the working structure of the 9p filesystem: * `/ctl`: Read/write control file for inputing system commands. Reading the file shows the status of the last input command: 1 for success, 0 for failure; `logout` is a special case, and the status code will be -1 if it was succesful. the following are valid command syntax: * `login PW`: Authenticate with `xrxs` -- password is hashed against realm password hash. * `logout`: Gracefully remove yourself from the users table. * `load CART`: Load a cartridge. * `chunk TYPE N`: Load data of type TYPE and chunk number N. * `create REALM`: Create a new realm (start a new game) -- must have a cartridge loaded * `protect PW`: Protect the curent realm with a password if you are the master. * `transfer USER`: Transfer ownership of the realm to another user. * `delete REALM`: Delete the realm off the server if you are the master and it is empty. * `enter REALM`: Join an existing realm. * `leave`: Leave the current realm. * `unload`: Unload the cartridge. * `/users`: Read-only; Self and others in the realm are readable from here, one per line. It contains only yourself before joining a realm. Your username on your machine is used as your username in `xrxs` -- if your name is taken, you will get an error on attaching. * `/carts`: Available game/app cartridges for this server, read only; Carts are listed per line upon reading the file. It is backed by files on the server in a directory structure like `carts/CART_NAME/{CART_NAME.rom, data/, realms/}`. * `/slot`: After loading the cartridge, its ROM is read from here; Read-only. * `/data/`: Any supporting data that comes with the cartridge will be found here; They are in three parts: `sprite`, `audio`, and `text`. While `uxn` has the ability to seek through a file up to 4GB in size, it can be beneficial to separate game assets into discrete files. The `chunk` command should be used to page different files into the service when needed. The files on the server should be like `TYPEN` where `TYPE` is one of `sprite`, `audio`, and `text`, and `N` is any sequence of characters (canonically a nonnegative integer). When first loading the cartridge, `N == 0`. Issuing the command `chunk TYPE XXX` will attempt to load data from file `carts/CART_NAME/data/TYPEXXX` into the correct data file. If `TYPE` is not one of `sprite`, `audio`, or `text`, or the file `TYPEXXX` doesn't exist in the data directory, the `chunk` command does nothing. * `/realms`: Open/saved realms, read-only. Realms and their associated universe are backed by real files on the server so that they can be preserved across service instantiations, in a directory structure like: `carts/CART_NAME/realms/REALM_NAME/{realm, universe}`. Realms can either be solo, open, or protected; Open or protected realms can have limited member numbers. Depending on the cartridge, these settings can be user-managed or managed by the cartridge itself. Realms are listed per line upon reading the file like: `REALM_NAME 1 4 1`. First would obviously be the name of the realm. The first number is number of members, second is member limit, third is 1 if protected, 0 if not. `0 1 1` represents a protected solo realm that is empty (saved game with password). `0 1 0` represents an unprotected solo realm that is empty (saved game with no password). * `/universe`: Write here to update serverside state for this cart/realm; Read from here to get the complete current state. This is backed by a key-value-pair list on the server. * `/scope`: Write here to tell the server the names of the `Atom`s (key/value pair of a `Universe`) you're interested in (one per line), and read from here to retrieve their values (one per line). In many cases this will be preferrable to fetching the entire `Universe`. * `/random`: Read-only, get a random number from 0 to 99. * `/grandom`: Read-only, get a random number from 0 to 99 -- These are doled out on a per-realm basis, and the number stays the same until everyone in the realm has had a chance to read it. If you've already read it this round or aren't in a realm, it will be empty. * `/version`: Read-only, outputs the version of the `xrxs` server. ### realm format Each realm directory on the server should have the following files: * `realm`: Basic data for the realm, file should contain only the maximum number of members, the master's name, and the password hash, if any (otherwise 0), separated by spaces. * `universe`: The actual game state for the realm as key value pairs, one per line, like `KEY = VALUE`; limit 15 characters for keys, 63 for values. The realm should be synchronized to disc when realm membership, limit, or password change. Fenagling some periodic autosave should be possible... ## configuration `config.h` in the source contains the following configuration macros: * `MAX_USERS`: the maximum number of simultaneous users able to attach to the `xrxs` service * `DATA_DIR`: the path to the root of the cartridge and realm storage; can be absolute or relative to the `xrxs` executable, but must have the trailing `/` ## build/run ### server The `xrxs` server is built/tested in a Linux environment with `plan9port` and the C standard library as the only dependencies. With minimal modifications it will probably run just as well on Plan9, *BSD, WSL, and MacOS. Running `./build.sh` from the `server` directory should build the `xrxs` executable. You can run a local server (for testing, split-screen games, or single-player games) with: ``` ./xrxs -m /path/to/mountpoint ``` or expose a service on the network (uses `9pserve` to support multiple users and gracefully handle disconnects) with: ``` ./xrxs-srv.sh start ``` Add the `-d` option to the above command to enable 9p debugging output. The default port is `5460` but can be changed by setting the `XRXS_PORT` environment variable. Similarly, you can stop the service with: ``` ./xrxs-srv.sh stop ``` The executable itself supports the following options, one of which is required (no options prints the help text): * `-m MOUNTPOINT`: mount the 9p filesystem locally at MOUNTPOINT * `-s SOCKET`: serve the 9p filesystem over a socket named SOCKET * `-v`: print the version information * `-h | --help`: show the help text ### client There are two versions of the client ROM. One is the normal `xrxs` client, and one is a standalone client for use as a generic `uxn` bootloader. The latter reads a ROM list out of a file called `index`, and appends the `.rom` extension to your selection and loads a file so named. Note that while the `9p` filesystem will be located under the parent directory of `./n`, the standalone bootloader assumes a flat filesystem. You can run `./build.sh` with no options to build the normal `xrxs` client, or with any of the following options: * `-r`: build the normal client and run it for local testing (don't mount the remote `9p` filesystem) * `-l`: build the standalone bootloader * `-lr`: build the standalone bootloader and run it When the client ROM has been built, run `./uxn-xrxs.sh` to mount the `9p` service and run the client. As with the server, the default port is `5460` but can be overridden with the `XRXS_PORT` environment variable. The default server address is `127.0.0.1` but can be similarly changed by setting the `XRXS_ADDR` environment variable. The scripts assume you have `uxnasm` and `uxnemu` in your `PATH`. `9pfuse` is used to mount the service, but other implementations could possibly be used.