nixos/profiles/serial.nix

   1 { pkgs, ... }:
   2 let
   3   # Based on https://unix.stackexchange.com/questions/16578/resizable-serial-console-window
   4   resize = pkgs.writeScriptBin "resize" ''
   5     export PATH=${pkgs.coreutils}/bin
   6     if [ ! -t 0 ]; then
   7       # not a interactive...
   8       exit 0
   9     fi
  10     TTY="$(tty)"
  11     if [[ "$TTY" != /dev/ttyS* ]] && [[ "$TTY" != /dev/ttyAMA* ]] && [[ "$TTY" != /dev/ttySIF* ]]; then
  12       # probably not a known serial console, we could make this check more
  13       # precise by using `setserial` but this would require some additional
  14       # dependency
  15       exit 0
  16     fi
  17     old=$(stty -g)
  18     stty raw -echo min 0 time 5
  19
  20     printf '\0337\033[r\033[999;999H\033[6n\0338' > /dev/tty
  21     IFS='[;R' read -r _ rows cols _ < /dev/tty
  22
  23     stty "$old"
  24     stty cols "$cols" rows "$rows"
  25   '';
  26 in
  27 {
  28   # set terminal size once after login
  29   environment.loginShellInit = "${resize}/bin/resize";
  30
  31   # allows user to change terminal size when it changed locally
  32   environment.systemPackages = [ resize ];
  33
  34   # default is something like vt220... however we want to get alt least some colors...
  35   systemd.services."serial-getty@".environment.TERM = "xterm-256color";
  36
  37   /*
  38     # also make grub respond on serial consoles
  39     boot.loader.grub.extraConfig = ''
  40     serial --unit=0 --speed=115200 --word=8 --parity=no --stop=1
  41     terminal_input --append serial
  42     terminal_output --append serial
  43     '';
  44   */
  45 }