#! /bin/sh

# Auto-install OpenBSD/amd64 6.6 to a QEMU guest machine.
#
# Run the following command to serve the OpenBSD mirror at http://127.0.0.1
# (port 80):
#
#   sudo python3 -m http.server \
#     --directory ./openbsd-vm/mirror \
#     --bind 127.0.0.1 80
#
# Pass the following options to ssh or scp to connect to the guest machine:
#
#   ssh \
#     -o "StrictHostKeyChecking no" \
#     -o "UserKnownHostsFile /dev/null" \
#     -o "Port 2222" \
#     puffy@127.0.0.1
#
# For example, the following command forwards port 8080 on the host to port 80
# on the guest:
#
#   ssh \
#     -o "StrictHostKeyChecking no" \
#     -o "UserKnownHostsFile /dev/null" \
#     -o "Port 2222" \
#     -N \
#     -L 127.0.0.1:8080:127.0.0.1:80 \
#     puffy@127.0.0.1
#
# Press C-a x to stop the guest machine. Press C-a h to show other options.
#
# The virtual network:
#
#   network    = 10.0.2.0/24
#   host       = 10.0.2.2
#   nameserver = 10.0.2.3
#   guest      = 10.0.2.15-31
#
# Port forwardings:
#
#   host:2222 -> guest:22
#
# Copyright (c) 2020 Stefan Kreutz <mail@skreutz.com>

set -o errexit
set -o nounset
set -o xtrace

# Set parameters.
VM_FILE="${VM_FILE-openbsd-vm.qcow2}"
DISK_SIZE="${DISK_SIZE-160G}"
CPU_COUNT="${CPU_COUNT-6}"
MEMORY_SIZE="${MEMORY_SIZE-4G}"

# Remove existing virtual machine if configuration changed.
if [ -e "${VM_FILE}" ] ;
then
  vm_created="$( stat -c %W "${VM_FILE}" )"
  for f in boot.conf disklabel install.conf install.site
  do
    if [ "${vm_created}" -lt "$( stat -c %Y "$f" )" ] ;
    then
      ( >&2 printf "%s changed. Recreating virtual machine." "$f" )
      rm "${VM_FILE}"
    fi
  done
fi

if [ ! -e "${VM_FILE}" ] ;
then

  # Download and verify OpenBSD/amd64 6.6 installation images and file sets.
  mkdir -p .openbsd-vm/mirror/pub/OpenBSD/6.6
  if [ ! -e .openbsd-vm/mirror/pub/OpenBSD/6.6/openbsd-66-base.pub ] ;
  then
    curl \
      --output .openbsd-vm/mirror/pub/OpenBSD/6.6/openbsd-66-base.pub \
      --silent \
      https://ftp.openbsd.org/pub/OpenBSD/6.6/openbsd-66-base.pub
  fi
  if [ ! -d .openbsd-vm/mirror/pub/OpenBSD/6.6/amd64 ] ;
  then
    mkdir -p .openbsd-vm/tmp
    rsync --recursive --delete --quiet \
      rsync://ftp.halifax.rwth-aachen.de/openbsd/6.6/amd64/ \
      .openbsd-vm/tmp/
    ( cd .openbsd-vm/tmp && \
      signify -C -q -p ../mirror/pub/OpenBSD/6.6/openbsd-66-base.pub -x SHA256.sig )
    mv .openbsd-vm/tmp .openbsd-vm/mirror/pub/OpenBSD/6.6/amd64
  fi

  # Create site-specific file set.
  if [ ! -x install.site ] ;
  then
    chmod +x install.site
  fi
  rm -f .openbsd-vm/mirror/pub/OpenBSD/6.6/amd64/site66.tgz
  tar -czf .openbsd-vm/mirror/pub/OpenBSD/6.6/amd64/site66.tgz install.site
  ( cd .openbsd-vm/mirror/pub/OpenBSD/6.6/amd64 && ls -l > index.txt )

  # Add public ssh key to install.conf.
  cp install.conf .openbsd-vm/mirror/
  if ! grep -q -e "^Public ssh key for user" install.conf ;
  then
    ssh_pub_key="$( cat ~/.ssh/id_rsa.pub )"
    echo "Public ssh key for user = ${ssh_pub_key}" \
      >> .openbsd-vm/mirror/install.conf
  fi

  # Copy disklabel template.
  cp disklabel .openbsd-vm/mirror/

  # Wait until the HTTP server is online.
  #
  # TODO: Serve HTTP and TFTP from another virtual machine to remove the
  # necessity to bind to a privileged port. Maybe use Linux' tftpd from Arch
  # Linux package tftp-hpa. Redirect ports using qemu.
  while [ ! "$( curl --silent --location --write-out '%{http_code}\n' --output /dev/null http://127.0.0.1/install.conf )" = 200 ] ;
  do
    ( >&2 printf "Please serve the directory ./openbsd-vm/mirror at http://127.0.0.1 (port 80).\n" )
    sleep 5
  done

  # Collect files to be served over TFTP.
  rm -rf .openbsd-vm/tftp
  mkdir .openbsd-vm/tftp
  ln -s ../mirror/pub/OpenBSD/6.6/amd64/pxeboot .openbsd-vm/tftp/auto_install
  ln -s ../mirror/pub/OpenBSD/6.6/amd64/bsd.rd .openbsd-vm/tftp/bsd.rd
  mkdir .openbsd-vm/tftp/etc
  cp boot.conf .openbsd-vm/tftp/etc/

  # Create copy-on-write disk image.
  qemu-img create -f qcow2 "${VM_FILE}" "${DISK_SIZE}"

fi

# Auto-install guest machine.
qemu-system-x86_64 \
  -enable-kvm \
  -m "${MEMORY_SIZE}" \
  -smp "cpus=${CPU_COUNT}" \
  -device e1000,netdev=n1 \
  -netdev user,id=n1,hostname=openbsd-vm,tftp=.openbsd-vm/tftp,bootfile=auto_install,hostfwd=tcp::2222-:22 \
  -drive "file=${VM_FILE},media=disk,if=virtio" \
  -nographic