#!/bin/bash
set -e

# Apply a sed expression using extended regular expressions in place to a
# file, if it exists.  The file is the first argument in order to work
# neatly with apply_conf_tweaks.
sed_conf()
{
  if [ -e "$1" ]; then
    sed -i -re "$2" "$1"
  fi
}

# Substitute a debconf answer into a configuration file with the syntax of
# /etc/default/grub.
merge_debconf_into_conf()
{
  local tmpfile; tmpfile="$1"
  local setting; setting="$2"
  local template; template="$3"

  db_get "$template"
  local value; value="$(echo "$RET" | sed -e 's,[$`"\],\\&,g')"
  if grep -q "^${setting}=" "$tmpfile"; then
    value="$(echo "$value" | sed -e 's,[\@],\\&,g')"
    sed -i -re "s@^(${setting}=).*@\1\"${value}\"@" "$tmpfile"
  else
    echo >> "$tmpfile"
    echo "${setting}=\"${value}\"" >> "$tmpfile"
  fi
}

# Apply the same configuration tweak to multiple files.
apply_conf_tweaks()
{
  local files; files="$1"
  local cmd; cmd="$2"
  local file
  shift 2

  for file in $files; do
    if [ -e "$file" ]; then
      "$cmd" "$file" "$@"
    fi
  done
}

# This only works on a Linux system with udev running.  This is probably the
# vast majority of systems where we need any of this, though, and we fall
# back reasonably gracefully if we don't have it.
cached_available_ids=
available_ids()
{
  local id path

  if [ "$cached_available_ids" ]; then
    echo "$cached_available_ids"
    return
  fi

  [ -d /dev/disk/by-id ] || return
  cached_available_ids="$(
    for path in /dev/disk/by-id/*; do
      [ -e "$path" ] || continue
      printf '%s %s\n' "$path" "$(readlink -f "$path")"
    done | sort -k2 -s -u | cut -d' ' -f1
  )"
  echo "$cached_available_ids"
}

# Returns non-zero and no output if no mapping can be found.
device_to_id()
{
  local id
  for id in $(available_ids); do
    if [ "$(readlink -f "$id")" = "$(readlink -f "$1")" ]; then
      echo "$id"
      return 0
    fi
  done
  # Fall back to the plain device name if there's no by-id link for it.
  if [ -e "$1" ]; then
    echo "$1"
    return 0
  fi
  return 1
}

# for Linux
sysfs_size()
{
  local num_sectors sector_size size
  # Try to find out the size without relying on a partitioning tool being
  # installed. This isn't too hard on Linux 2.6 with sysfs, but we have to
  # try a couple of variants on detection of the sector size.
  if [ -e "$1/size" ]; then
    num_sectors="$(cat "$1/size")"
    sector_size=512
    if [ -e "$1/queue/logical_block_size" ]; then
      sector_size="$(cat "$1/queue/logical_block_size")"
    elif [ -e "$1/queue/hw_sector_size" ]; then
      sector_size="$(cat "$1/queue/hw_sector_size")"
    fi
    size="$(expr "$num_sectors" \* "$sector_size" / 1000 / 1000)"
  fi
  [ "$size" ] || size='???'
  echo "$size"
}

maybe_udevadm()
{
  if command -v udevadm >/dev/null 2>&1; then
    udevadm "$@" || true
  fi
}

# Returns value in $RET, like a debconf command.
describe_disk()
{
  local disk id sysfs_path disk_basename size model
  disk="$1"
  id="$2"

  model=
  case $(uname -s) in
    Linux)
      sysfs_path="$(maybe_udevadm info -n "$disk" -q path)"
      if [ -z "$sysfs_path" ]; then
        sysfs_path="/block/$(printf %s "${disk#/dev/}" | sed 's,/,!,g')"
      fi
      size="$(sysfs_size "/sys$sysfs_path")"

      model="$(maybe_udevadm info -n "$disk" -q property | sed -n 's/^ID_MODEL=//p')"
      if [ -z "$model" ]; then
        model="$(maybe_udevadm info -n "$disk" -q property | sed -n 's/^DM_NAME=//p')"
        if [ -z "$model" ]; then
          model="$(maybe_udevadm info -n "$disk" -q property | sed -n 's/^MD_NAME=//p')"
          if [ -z "$model" ] && command -v dmsetup >/dev/null 2>&1; then
            model="$(dmsetup info -c --noheadings -o name "$disk" 2>/dev/null || true)"
          fi
        fi
      fi
    ;;
  esac

  [ "$model" ] || model='???'

  db_subst grub-pc/disk_description DEVICE "$disk"
  db_subst grub-pc/disk_description SIZE "$size"
  db_subst grub-pc/disk_description MODEL "$model"
  db_metaget grub-pc/disk_description description
}

# Returns value in $RET, like a debconf command.
describe_partition()
{
  local disk part id path sysfs_path diskbase partbase size
  disk="$1"
  part="$2"
  id="$3"
  path="$4"

  sysfs_path="$(maybe_udevadm info -n "$part" -q path)"
  if [ -z "$sysfs_path" ]; then
    diskbase="${disk#/dev/}"
    diskbase="$(printf %s "$diskbase" | sed 's,/,!,g')"
    partbase="${part#/dev/}"
    partbase="$(printf %s "$partbase" | sed 's,/,!,g')"
    sysfs_path="/block/$diskbase/$partbase"
  fi
  size="$(sysfs_size "/sys$sysfs_path")"

  db_subst grub-pc/partition_description DEVICE "$part"
  db_subst grub-pc/partition_description SIZE "$size"
  db_subst grub-pc/partition_description PATH "$path"
  db_metaget grub-pc/partition_description description
}

usable_partitions()
{
  local last_partition path partition partition_id

  last_partition=
  for path in / /boot /boot/grub; do
    partition="$(grub-probe -t device "$path" || true)"
    if [ -z "$partition" ] || [ "$partition" = "$last_partition" ]; then
      continue
    fi
    partition_id="$(device_to_id "$partition" || true)"
    echo "$path:$partition_id"
    last_partition="$partition"
  done | sort -t: -k2
}

get_mountpoint()
{
  local relpath boot_mountpoint

  relpath="$(grub-mkrelpath "$1")"
  boot_mountpoint="${1#$relpath}"
  echo "${boot_mountpoint:-/}"
}

config_item()
{
  for x in /etc/default/grub /etc/default/grub.d/*.cfg; do
    if [ -e "$x" ]; then
	# Lose any output here so we don't confuse our
	# caller. The xen packages echo stuff here, Aargh!
      . "$x" > /dev/null
    fi
  done
  if [ "$(eval echo "\${$1+set}")" = set ]; then
    eval echo "\$$1"
  else
    return
  fi
}

running_in_container()
{
  type systemd-detect-virt >/dev/null 2>&1 && systemd-detect-virt --quiet --container
}

no_nvram_arg() {
    db_get grub2/update_nvram
    if [ "$RET" = false ]; then
        echo "--no-nvram"
    fi
}

run_grub_install()
{
    if ! grub-install $@ ; then
        echo "Failed: grub-install $@" >&2
        echo "WARNING: Bootloader is not properly installed, system may not be bootable" >&2
    fi
}

case "$1" in
  configure)
    . /usr/share/debconf/confmodule

    devicemap_regenerated=

    if egrep -q '^[[:space:]]*post(inst|rm)_hook[[:space:]]*=[[:space:]]*(/sbin/|/usr/sbin/)?update-grub' /etc/kernel-img.conf 2>/dev/null; then
      echo 'Removing update-grub hooks from /etc/kernel-img.conf in favour of' >&2
      echo '/etc/kernel/ hooks.' >&2
      sed -ri /etc/kernel-img.conf -e '\%^[[:space:]]*post(inst|rm)_hook[[:space:]]*=[[:space:]]*(/sbin/|/usr/sbin/)?update-grub%d'
    fi

    mkdir -p /boot/grub

    tmp_default_grub="$(mktemp -t grub.XXXXXXXXXX)"
    trap "rm -f ${tmp_default_grub}" EXIT
    cp -p /usr/share/grub/default/grub ${tmp_default_grub}

    # Apply configuration from debconf to both the template configuration
    # file (so that any ucf conflict resolution is shown with the configured
    # values in place) and to /etc/default/grub (in order that debconf
    # changes are effective even if we have to use UCF_FORCE_CONFFOLD=1).
    #
    # The config script takes care to read current values from
    # /etc/default/grub before possibly prompting the user to change them,
    # so this should comply with policy's strictures on configuration file
    # handling: the debconf prompts constitute an explicit administrator
    # request to change the configuration file.
    #
    # If the administrator changes their answers to any of these debconf
    # questions in the same run as a change to the template, then they'll
    # get a spurious ucf conflict.  To fix this, we'd need to keep track of
    # the old answers, substitute the old answers into $tmp_default_grub,
    # and substitute the new answers into /etc/default/grub.  Fortunately,
    # debconf won't normally ask these questions again during an upgrade, so
    # this should be rare in practice.

    conf_files="$tmp_default_grub /etc/default/grub"

    apply_conf_tweaks "$conf_files" merge_debconf_into_conf GRUB_CMDLINE_LINUX grub2/linux_cmdline
    apply_conf_tweaks "$conf_files" merge_debconf_into_conf GRUB_CMDLINE_LINUX_DEFAULT grub2/linux_cmdline_default

    # Horrible stuff here, as the os-prober option is a negative
    # setting (GRUB_DISABLE_OS_PROBER). To not confuse people with
    # double negative questions in templates, invert it here.
    db_get grub2/enable_os_prober
    if [ "$RET" = false ]; then
      # enable == false -> put in place the commented-out default
      # #GRUB_DISABLE_OS_PROBER=false that we ship with
      apply_conf_tweaks "$conf_files" sed_conf 's/^.*GRUB_DISABLE_OS_PROBER.*$/#GRUB_DISABLE_OS_PROBER=false/'
    else
      # enable == true -> put in place a valid GRUB_DISABLE_OS_PROBER=false
      apply_conf_tweaks "$conf_files" sed_conf 's/^.*GRUB_DISABLE_OS_PROBER.*$/GRUB_DISABLE_OS_PROBER=false/'
    fi

    case @PACKAGE@ in
      grub-pc)
        apply_conf_tweaks "$conf_files" merge_debconf_into_conf GRUB_TIMEOUT grub-pc/timeout
        apply_conf_tweaks "$conf_files" sed_conf 's/^(GRUB_TIMEOUT=)"([0-9][0-9]*)"/\1\2/'
        db_get grub-pc/hidden_timeout
        if [ "$RET" = false ]; then
          apply_conf_tweaks "$conf_files" sed_conf 's/^GRUB_HIDDEN_TIMEOUT=/#&/'
        fi
      ;;
      grub-ieee1275)
        if grep ^platform /proc/cpuinfo | grep -q PowerNV; then
		cat <<-EOF >>"$tmp_default_grub"

		# Disable os-prober for ppc64el on the PowerNV platform (for Petitboot)
		GRUB_DISABLE_OS_PROBER=true
		EOF
        fi
        ;;
    esac

    # If the template configuration file hasn't changed, then no conflict is
    # possible.  ucf can't figure this out for itself since we apply
    # debconf-based customisations on top of the template configuration
    # file.
    if [ -e /var/lib/grub/ucf/grub.previous ] && \
       cmp -s /usr/share/grub/default/grub /var/lib/grub/ucf/grub.previous && \
       [ -e /etc/default/grub ]; then
      ucf_env=UCF_FORCE_CONFFOLD=1
    else
      ucf_env=
    fi

    env $ucf_env ucf --three-way --debconf-ok --sum-file=/usr/share/grub/default/grub.md5sum "$tmp_default_grub" /etc/default/grub
    cp -aZ /usr/share/grub/default/grub /var/lib/grub/ucf/grub.previous
    package="$(ucfq --with-colons /etc/default/grub | cut -d : -f 2)"
    if echo $package | grep -q "^grub-" ; then
      ucfr --force @PACKAGE@ /etc/default/grub
    else
      ucfr @PACKAGE@ /etc/default/grub
    fi

    case @PACKAGE@ in
      grub-pc)
        if running_in_container; then
          # Skip grub-install in containers.
          :
        elif test -e /boot/grub/core.img || \
             test -e /boot/grub/@FIRST_CPU_PLATFORM@/core.img; then
          question=grub-pc/install_devices
          priority=high
          device_map="$(grub-mkdevicemap -m - | grep -v '^(fd[0-9]\+)' || true)"
          devices="$(echo "$device_map" | cut -f2)"
          db_get grub-pc/install_devices
          valid=1
          for device in $RET; do
            if [ ! -e "${device%,}" ]; then
              valid=0
              break
            fi
          done
          if [ "$valid" = 0 ]; then
            question=grub-pc/install_devices_disks_changed
            priority=critical
            db_set "$question" "$RET"
            db_fset "$question" seen false
            db_fset grub-pc/install_devices_empty seen false
          fi

          while :; do
            ids=
            descriptions=
            partitions="$(usable_partitions)"
            for device in $devices; do
              disk_id="$(device_to_id "$device" || true)"
              if [ "$disk_id" ]; then
                ids="${ids:+$ids, }$disk_id"
                describe_disk "$(readlink -f "$device")" "$disk_id"
                RET="$(printf %s "$RET" | sed 's/,/\\,/g')"
                descriptions="${descriptions:+$descriptions, }$RET"
                for partition_pair in $partitions; do
                  partition_id="${partition_pair#*:}"
                  if [ "${partition_id#$disk_id-part}" != "$partition_id" ]; then
                    ids="${ids:+$ids, }$partition_id"
                    describe_partition "$(readlink -f "$device")" "$(readlink -f "$partition_id")" "$partition_id" "$(get_mountpoint "${partition_pair%%:*}")"
                    RET="$(printf %s "$RET" | sed 's/,/\\,/g')"
                    descriptions="${descriptions:+$descriptions, }$RET"
                  fi
                done
              fi
            done
            # Some "partitions" may in fact be at the disk level, e.g. RAID.
            # List these as well if they haven't already been listed.
            for partition_pair in $partitions; do
              partition_id="${partition_pair#*:}"
              if [ "${partition_id#*-part}" = "$partition_id" ]; then
                case ", $ids, " in
                  ", $partition_id, ") ;;
                  *)
                    ids="${ids:+$ids, }$partition_id"
                    describe_disk "$(readlink -f "$partition_id")" "$partition_id"
                    RET="$(printf %s "$RET" | sed 's/,/\\,/g')"
                    descriptions="${descriptions:+$descriptions, }$RET"
                    ;;
                esac
              fi
            done
            db_subst "$question" RAW_CHOICES "$ids"
            db_subst "$question" CHOICES "$descriptions"
            db_input "$priority" "$question" || true
            db_go
            db_get "$question"
            failed_devices=
            echo "@PACKAGE@: Running grub-install ..."
            for i in $RET; do
              real_device="$(readlink -f "${i%,}")"
              if [ ! -e "$real_device" ]; then
                echo "$real_device does not exist, so cannot grub-install to it!" >&2
                failed_devices="$failed_devices $real_device"
              else
                if grub-install --target=i386-pc --force --no-floppy $real_device ; then
                  echo "  grub-install success for $real_device"
                  # We just installed GRUB 2; then also generate grub.cfg.
                  touch /boot/grub/grub.cfg
                else
                  echo "  grub-install failure for $real_device"
                  failed_devices="$failed_devices $real_device"
                fi
              fi
            done

            if [ "$question" != grub-pc/install_devices ] && [ "$RET" ]; then
              # XXX cjwatson 2019-02-26: The description of
              # grub-pc/install_devices_disks_changed ought to explain that
              # selecting no devices will leave the configuration unchanged
              # so that you'll be prompted again next time, but it's a bit
              # close to the Debian 10 release to be introducing new
              # translatable text.  For now, it should be sufficient to
              # avoid losing configuration data.
              db_set grub-pc/install_devices "$RET"
              db_fset grub-pc/install_devices seen true
            fi

            if [ "$failed_devices" ]; then
              db_subst grub-pc/install_devices_failed FAILED_DEVICES "$failed_devices"
              db_fset grub-pc/install_devices_failed seen false
              if db_input critical grub-pc/install_devices_failed; then
                db_go
                db_get grub-pc/install_devices_failed
                if [ "$RET" = true ]; then
                  break
                else
                  db_fset "$question" seen false
                  db_fset grub-pc/install_devices_failed seen false
                  continue
                fi
              else
                echo "You must correct your GRUB install devices before proceeding:" >&2
                echo >&2
                echo "  DEBIAN_FRONTEND=dialog dpkg --configure grub-pc" >&2
                echo "  dpkg --configure -a" >&2
                exit 1 # noninteractive
              fi
            fi

            db_get "$question"
            if [ -z "$RET" ]; then
              # Reset the seen flag if the current answer is false, since
              # otherwise we'll loop with no indication of why.
              db_get grub-pc/install_devices_empty
              if [ "$RET" = false ]; then
                db_fset grub-pc/install_devices_empty seen false
              fi
              if db_input critical grub-pc/install_devices_empty; then
                db_go
                db_get grub-pc/install_devices_empty
                if [ "$RET" = true ]; then
                  break
                else
                  db_fset "$question" seen false
                  db_fset grub-pc/install_devices_empty seen false
                fi
              else
                db_get grub-pc/install_devices_empty
                if [ "$RET" = true ]; then
                  break
                else
                  echo "You must correct your GRUB install devices before proceeding:" >&2
                  echo >&2
                  echo "  DEBIAN_FRONTEND=dialog dpkg --configure grub-pc" >&2
                  echo "  dpkg --configure -a" >&2
                  exit 1 # noninteractive
                fi
              fi
            else
              break
            fi
          done
        fi

        # /boot/grub/ has more chances of being accessible by GRUB
        for i in /usr/share/grub/unicode.pf2 ; do
          if test -e $i ; then
            cp $i /boot/grub/
          fi
        done
      ;;

      grub-efi-ia32|grub-efi-amd64|grub-efi-arm|grub-efi-arm64|grub-efi-riscv64|grub-efi-loong64)
        bootloader_id="$(config_item GRUB_DISTRIBUTOR | tr A-Z a-z | \
                         cut -d' ' -f1)"
        case $bootloader_id in
          kubuntu) bootloader_id=ubuntu ;;
          devuan) bootloader_id=debian ;;
        esac
        case @PACKAGE@ in
          grub-efi-ia32)  target=i386-efi ;;
          grub-efi-amd64) target=x86_64-efi ;;
          grub-efi-arm)   target=arm-efi ;;
          grub-efi-arm64) target=arm64-efi ;;
          grub-efi-riscv64) target=riscv64-efi ;;
          grub-efi-loong64) target=loongarch64-efi ;;
        esac
        if [ "$bootloader_id" ] && [ -e "/boot/grub/$target/core.efi" ]; then
          db_get grub2/force_efi_extra_removable
          if [ "$RET" = true ]; then
            FORCE_EXTRA_REMOVABLE="--force-extra-removable"
          fi
          NO_NVRAM="$(no_nvram_arg)"
          run_grub_install --target="$target" "$FORCE_EXTRA_REMOVABLE" "$NO_NVRAM"
        fi

        # /boot/grub/ has more chances of being accessible by GRUB
        for i in /usr/share/grub/unicode.pf2 ; do
          if test -e $i ; then
            cp $i /boot/grub/
          fi
        done

        if type update-secureboot-policy >/dev/null 2>&1; then
          update-secureboot-policy || true
        fi
      ;;

      grub-ieee1275)
        case $(dpkg --print-architecture) in
          powerpc|ppc64|ppc64el)
            # Output may be empty; if so, just update the core image but
            # don't install it to any PReP partition.
            prep_bootdev="$(/usr/lib/grub/powerpc-ieee1275/prep-bootdev)"
            NO_NVRAM="$(no_nvram_arg)"
            run_grub_install --target=powerpc-ieee1275 $prep_bootdev "$NO_NVRAM"
          ;;
        esac
      ;;

      grub-xen)
        # Install for x86_64 regardless of arch, since a 32-bit userspace can still boot with a 64-bit kernel.
        mkdir -p /boot/xen
        run_grub_install --target=x86_64-xen
        case $(dpkg --print-architecture) in
          i386)
            run_grub_install --target=i386-xen
          ;;
        esac
        # Similarly, the PVH boot loader is usable regardless of arch.
        run_grub_install --target=i386-xen_pvh
      ;;
    esac

    # If grub.cfg has been generated, update it.
    if test -e /boot/grub/grub.cfg && ! running_in_container; then
      update-grub 3>&-
    fi
  ;;
  abort-upgrade|abort-remove|abort-deconfigure)
  ;;
  *)
    echo "postinst called with unknown argument \`$1'" >&2
    exit 1
  ;;
esac

# dh_installdeb will replace this with shell code automatically
# generated by other debhelper scripts.

#DEBHELPER#

exit 0