#!/bin/sh -e
#    run-hurd.sh, a script to fetch and run Debian GNU (Hurd) using qemu, aspiring to be fool-proof
#    Copyright (C) 2026  alicia@ion.nu
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

bit64=false
redownload=false
fsck=false
daemon=false
expand=''
while getopts "6rfde:" opt; do
  case "$opt" in
    6) bit64=true;;
    r) redownload=true;;
    f) fsck=true;;
    d) daemon=true;;
    e) expand="$OPTARG"
       if ! echo "$expand" | grep -q '[0-9]\+[BKMGTP]'; then
         echo 'Invalid format for expansion. Expected number followed by unit (B for bytes, K for kilobytes, M for megabytes etc.)'
         exit 1
       fi;;
    *) echo "Usage: ${0} [options]"
       echo 'Options include:'
       echo ' -6        = use the new 64bit build'
       echo ' -r        = redownload instead of booting existing image'
       echo ' -f        = run a filesystem check (requires losetup and fsck.ext2)'
       echo ' -d        = daemonize, start qemu and return to the shell'
       echo ' -e <size> = expand disk image to the given size'
# TODO: option for curses display (for non-GUI environments and/or to translate keyboard because Hurd console currently lacks keyboard layouts outside US qwerty)
# TODO: option for VNC display
       exit;;
  esac
done
if [ ! -e debian-hurd.img ] || "$redownload"; then
  rm -f debian-hurd.img.tar.gz
  if "$bit64"; then
    wget 'https://cdimage.debian.org/cdimage/ports/latest/hurd-amd64/debian-hurd.img.tar.gz'
  else
    wget 'https://cdimage.debian.org/cdimage/ports/latest/hurd-i386/debian-hurd.img.tar.gz'
  fi
  image="`tar -xvzf debian-hurd.img.tar.gz`"
  mv "$image" debian-hurd.img
fi
if "$fsck"; then
# TODO: Dynamically figure out which way (if any, maybe user is root) to run these as root
  disk="`sudo losetup -fP --show debian-hurd.img`"
  if [ -z "$disk" ]; then echo 'Failed to losetup the disk image. Is losetup installed?'; exit 1; fi
  if [ -e "${disk}p5" ]; then
    sudo fsck.ext2 -fy "${disk}p5"
  else
    sudo fsck.ext2 -fy "${disk}p2" # 32bit doesn't use the extended partition
  fi
  sudo losetup -d "$disk"
fi
if [ -n "$expand" ]; then
  num="`echo "$expand" | sed -e 's/[A-Z]$//'`"
  unit="`echo "$expand" | sed -e 's/^[0-9]*//'`"
  dd if=/dev/zero of=debian-hurd.img bs="1${unit}" count=0 seek="$num"
  disk="`sudo losetup -fP --show debian-hurd.img`"
  # TODO: Unify the losetup calls?
  if [ -z "$disk" ]; then echo 'Failed to losetup the disk image. Is losetup installed?'; exit 1; fi
  sudo parted "$disk" resizepart 2 '100%' # Resize the extended partition
  sudo parted "$disk" resizepart 5 '100%' || true # Resize the filesystem's partition therein (unless it's 32bit and doesn't have the extended partition)
  if [ -e "${disk}p5" ]; then
    sudo resize2fs "${disk}p5"
  else
    sudo resize2fs "${disk}p2"
  fi
  sudo losetup -d "$disk"
fi
runqemu()
{
  kvm="`grep -q ' \(svm\|vmx\)' /proc/cpuinfo && echo '--enable-kvm'`"
  # I think 32bit code should work even if we run x86_64 qemu?
  # From some testing, it appears -M q35 is not needed for 64bit Hurd, but breaks 32bit Hurd. Therefor omitting it
  qemu-system-x86_64 ${kvm} -m 2G -drive cache=writeback,file=debian-hurd.img -net user,hostfwd=tcp:127.0.0.1:2222-:22 -net nic,model=e1000
}
if "$daemon"; then
  runqemu > /dev/null 2> /dev/null &
else
  runqemu
fi