recap

over the past few years of visiting university i’ve always appreciated a friend’s discord status, showcasing the most classic vim exit joke unpaid sponsorship

so.. how did it all start?

been a while on wsl (ubuntu 24.04) with arch on my laptop & it’s been bugging my mind to not have a proper (at this point in time, a non-ai driven) editor. i was always open to try new things (np++, mousepad, helix, nano you name it). tl;dr i enjoy vim controls & what it offers for its minimality being installed on majority of distros. recently also picked up on lazyvim after being glued to primeagen’s barebone nvim config, hence i thought showing it off in discord, like every arch glazer, would be cool

done some digging and i came across two fantastic articles

with a little configuration i was able to get the passthrough to work

first things first, the prerequisites

  • socat - multipurpose, bidirectional socket relay
  • npipereleay - bridges windows named pipes to unix domain sockets
  • openssh-server/client - transpots unix socket across namespaces
  • a compatible plugin to display it on discord

below is an automatic install of all dependencies on ubuntu 24.04

sh 
0
1
2
3
4
5
6
7
8

# packages
sudo apt install socat openssh-server openssh-client -y

# npiperelay
cd /tmp
wget https://github.com/jstarks/npiperelay/releases/download/v0.1.0/npiperelay_windows_amd64.zip
unzip -j npipe* npiperelay.exe
chmod +x /tmp/npiperelay.exe
sudo mv /tmp/npiperelay.exe /usr/local/bin/

verify that the exe is in the correct path with execution permissions (--x)

sh 
0
1

ls -l "$(command -v npiperelay.exe)" 
-rwxr-xr-x 1 vah vah 1872384 Jul  2  2020 /usr/local/bin/npiperelay.exe

the ipc path varies depending on the environment you are using (see here or below)

  • ios: /var/run/discord-ipc-0
  • macos: $TMPDIR/discord-ipc-0
  • windows: [[\\.\pipe\]]discord-ipc-0
  • linux: $XDG_RUNTIME_DIR/discord-ipc-0

please adjust the socket path below to match your os if you are not on wsl

sh 
0
1
2
3
4
5
6
7

# socat forwards its byte stream to npiperelay,
# which attaches to the windows named pipe \\.\pipe\discord-ipc-0
socat UNIX-LISTEN:/tmp/discord-ipc-0,fork \
EXEC:"npiperelay.exe -ei -s //./pipe/discord-ipc-0",nofork &

# verify it exists + socket (s) bit
ls -l /tmp/discord-ipc-0
srwxr-xr-x 1 vah vah 0 Feb 27 17:13 /tmp/discord-ipc-0

obviously running this manually every time gets annoying, so we can wrap it inside our shell config (bash, zsh, etc.)

sh 
 0
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

# credits: https://gist.github.com/mousebyte/af45cbecaf0028ea78d0c882c477644a#aliasing-nvim)
# slightly modified by me
nvim () {
  if ! pgrep -f "UNIX-LISTEN:/tmp/discord-ipc-0" >/dev/null; then
    [ -e /tmp/discord-ipc-0 ] && rm -f /tmp/discord-ipc-0
    socat UNIX-LISTEN:/tmp/discord-ipc-0,fork \
      EXEC:"npiperelay.exe -ei -s //./pipe/discord-ipc-0",nofork &
  fi
  command nvim "$@"
}

# optional aliases if you prefer typing 'v'/'vim' over 'nvim'
alias v="nvim"
alias vim="nvim"

this function intends to shadow the nvim binary, ensuring the alias facilitates the consistent loading of the ipc mechanism upon startup

don’t forget to reload your shell / source it

sh 
0

source ~/.zshrc

forwarding the socket over ssh

onwards, i will partially follow this post with minor adjustments to properly compile with wsl

the relay created earlier exposes /tmp/discord-ipc-0, however, nvim expecets the discord ipc socket in the linux user runtime directory (/run/user/1000/)

to bridge this namepsace gap, we installed openssh, which conveniently enough is capable of unix domain socket forward via RemoteForward

this effectively maps:

/tmp/discord-ipc-0    ->    /run/user/1000/discord-ipc-0
(wsl relay socket)          (linux runtime socket)

firstly, get your wsl instance ip

sh 
0

ip a | grep 'inet '

add the following snippet to ~/.ssh/config

sh 
0
1
2
3

Match host <wsl-ip> exec "mkdir -p /tmp && touch /tmp/discord-ipc-0"
  Host <wsl-ip>
  User <your-user>
  RemoteForward /run/user/1000/discord-ipc-0 /tmp/discord-ipc-0

then create a directory for discord.conf & enable StreamLocalBindUnlink

sh 
0
1
2

sudo mkdir -p /etc/ssh/sshd_config.d
echo "StreamLocalBindUnlink yes" | sudo tee -a /etc/ssh/sshd_config.d/discord.conf
sudo systemctl restart ssh

lastly, establish the loopback ssh session from within ssh

sh 
0
1

ssh -v <wsl-ip>
socat -u OPEN:/dev/null UNIX-CONNECT:/run/user/1000/discord-ipc-0

if there is no error, you’re good to go to install the plugin

the actual plugin-part

if you’re using lazyvim, follow along, otherwise tweak it from the plugin installation reference depending on your nvim distro

lua 
0
1
2
3
4
5

return {
  "vyfor/cord.nvim",
  opts = {
    -- additional config
  }
}

sync with your package manager (:Lazy sync) & relaunch nvim

that’s pretty much it!

in case you want to troubleshoot, simply run :checkhealth cord inside your nvim distro to see what could be missing

ok so.. wtf is happening?

discord exposes windows named pipe
|
└─ \\.\pipe\discord-ipc-0     # discord binds to this socket on windows
    |
    └─ npiperelay.exe         # bridges windows pipe to the wsl unix socket
      |
      └─ /tmp/discord-ipc-0   # wsl unix socket
          |
          └─ ssh remoteforward
              |
              └─ /run/user/1000/discord-ipc-0   # forward runtime socket
                  |
                  └─ nvim rpc plugin   # cord.nvim

wsl2 runs a real linux kernel inside a lightweight vm, therefore windows applications cannot directly access its unix domain socket -> nvim expects a unix domain socket

the solution inserts a bidirectional relay that translates between these ipc primitives & forwards the stream into the linux user runtime space