install

#!/bin/bash

set -eu

here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

## Bring in some helper functions
source "$here/util"

## Sanity-check
log_start "Checking environment... "
check_existence "mount"
check_existence "modprobe"
check_existence "chroot"
check_existence "wget"
check_existence "sed"
check_existence "grep"
check_existence "unsquashfs"
check_existence "mktemp"
check_existence "id"
check_existence "sha256sum"
log_end "seems sane"

if [ -d /sys/firmware/efi ];
then
  log "UEFI systems are not supported yet. See issue #30 on github." >&2
  exit 1
fi

## Setup essential variables; allow overriding with input
root_mount=$(mount | grep "/ " | sed 's/ /\n/' | head -n1)
root_type=$(mount | grep -Eo "/ type \w+" | sed 's/ /\n/g' | tail -n1)
if grep '/dev/nvme' <<< $root_mount >/dev/null; then
  grub_device=$(echo $root_mount | sed "s|p[0-9]\+$||");
elif grep '/dev/sd' <<< $root_mount >/dev/null; then
  grub_device=$(echo $root_mount | sed "s|[0-9]\+||");
elif grep '/dev/vd' <<< $root_mount >/dev/null; then
  grub_device=$(echo $root_mount | sed "s|[0-9]\+||");
else
  log "Unable to determine your grub boot device! Please specify with the -g option."
fi
working_directory=$(mktemp -d)

## Try to work out which architecture to use
set +e
  arch=$(uname -a | grep -o "x86_64" | head -n1)
set -e
[ ! "$arch" = "x86_64" ] && arch=i686

primary_version=16.09
secondary_version=680.4e14fd5
full_version=$primary_version.$secondary_version
minimal_iso=nixos-minimal-$full_version-${arch}-linux.iso
graphical_iso=nixos-graphical-$full_version-${arch}-linux.iso
iso=$minimal_iso
minimal_checksum=8700fd1861e83dba0c3c2cb348099d2499b2c52844d1771f1aacbf7458990bc8
graphical_checksum=f1144de2645b1d099035416cb335e33cb56fdf71c8f8900c75a6a91ac2f49464
checksum=$minimal_checksum

minimal_space=3
graphical_space=5
required_space=$minimal_space
extra_config=$(readlink -f default-extra-config.nix)
digitalocean=false

while getopts ":g:r:t:Gdw:c:h" opt; do
  case $opt in
    g)
      grub_device=$OPTARG
      ;;
    r)
      root_mount=$OPTARG
      ;;
    t)
      root_type=$OPTARG
      ;;
    G)
      iso=$graphical_iso
      required_space=$graphical_space
      checksum=$graphical_checksum
      ;;
    d)
      digitalocean=true
      ;;
    w)
      working_directory=$OPTARG
      ;;
    c)
      extra_config=$(readlink -f $OPTARG)
      if [ ! -f $extra_config ];
      then
        log "ERROR extra config file missing: $extra_config" >&2
        exit 1
      fi
      ;;
    h)
      show_help "$0"
      ;;
    \?)
      log "ERROR invalid option: -$OPTARG" >&2
      exit 1
      ;;
    :)
      log "ERROR option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

if [ "$(id -u)" != "0" ]; then
  log "You need to be root to do this"
  exit 1
fi

space=$(df -B 1G "$working_directory" | tail -n1 | sed 's/ \+/ /g' | cut -d' ' -f4)
if [ "$space" -lt "$required_space" ];
then
  log "WARNING: It *looks* like you don't have enough space for the install"
  log "You need ~${minimal_space}GB for the minimal ISO and ~${graphical_space}GB for the graphical ISO"
  log_start "Continue anyway? [yn] "
  read -n 1 -r
  log_end
  if [[ ! $REPLY =~ ^[Yy]$ ]]
  then
    log "Exiting; nothing was harmed"
    exit 1
  fi
fi

## Give one last chance to back out
log "NixOS installer (nixos-in-place)"
log "   GRUB => $grub_device"
log "   Root => $root_mount ($root_type)"
log "   ISO => $iso"
log "   Digital Ocean => $digitalocean"
log "   Working directory => $working_directory"
log "   Extra config => $extra_config"
log_start "Continue? [yn] "
read -n 1 -r
log_end
if [[ ! $REPLY =~ ^[Yy]$ ]]
then
  log "Exiting; nothing was harmed"
  exit 1
fi

pushd "$working_directory"
  log "Downloading NixOS $iso"
  mkdir -p mnt host/nix

  url=https://d3g5gsiof5omrk.cloudfront.net/nixos/$primary_version/nixos-$full_version
  wget -c $url/$iso

  # From $url/$iso.sha256
  log "Validating checksum"
  sha256sum -c <(echo "$checksum $iso")

  log "Extracting ISO"
  modprobe loop
  mount -o loop $iso mnt
    unsquashfs -d host/nix/store mnt/nix-store.squashfs '*'
  umount mnt
  rm -rf ./mnt

  ## Setup the chroot environment before install
  log "Embarking stage1!"
  "$here/stage1" "$here" "$root_mount" "$root_type" "$grub_device" "$digitalocean" "$extra_config"

  ## Minimize residual space usage
  # /var/empty is immutable https://github.com/NixOS/nixpkgs/pull/18365
  chattr -i ./host/var/empty
  rm -rf ./host
popd

## Installation is complete
log_start "Reboot into NixOS now? [yn] "
read -n 1 -r || REPLY=n
log_end
[[ $REPLY =~ ^[Yy]$ ]] && reboot