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NetHack over Gemini Proof-of-Concept

gemini://gemhack.dimakrasner.com

This is easily one of the ugliest pieces of software I've ever written.

┌────────────────────────────────────────────────────────────────────────────────┐
│                       It is written in the Book of Lugh:                       │
│                                                                                │
│                           After the Creation, the cruel god Moloch rebelled    │
│                           against the authority of Marduk the Creator.         │
│                           Moloch stole from Marduk the most powerful of all    │
│                           the artifacts of the gods, the Amulet of Yendor,     │
│                           and he hid it in the dark cavities of Gehennom, the  │
│                           Under World, where he now lurks, and bides his time. │
│                                                                                │
│                       Your god Lugh seeks to possess the Amulet, and with it   │
│                       to gain deserved ascendance over the other gods.         │
│                                                                                │
│                       You, a newly trained Gallant, have been heralded         │
│                       from birth as the instrument of Lugh.  You are destined  │
│                       to recover the Amulet for your deity, or die in the      │
│                       attempt.  Your hour of destiny has come.  For the sake   │
│                       of us all:  Go bravely with Lugh!                        │
│                       --More--                                                 │
│                                               ........|                        │
│                                               |...@u..|                        │
│                                               ---------                        │
│                                                                                │
│Root the Gallant               St:15 Dx:8 Co:12 In:7 Wi:16 Ch:17 Lawful         │
│Dlvl:1 $:0 HP:16(16) Pw:4(4) AC:3 Xp:1                                          │
└────────────────────────────────────────────────────────────────────────────────┘

It consists of:

NetHack, running in a chroot environment
A seccomp-based sandbox that runs the game under a pty, injects commands received through a Unix socket into the game's stdin and splice()s the game's raw output (with terminal escape sequences) to stdout
A Go tool with the sandbox stdout as its stdin, which emulates a VT100 and dumps the 80x24 terminal contents to a file every second
gmnisrv with CGI that starts the game, reads the dump, or sends input to the sandbox

https://github.com/seccomp/libseccomp

https://github.com/markkurossi/vt100