#!/bin/sh
set -eu
export LC_ALL=C.UTF-8
export SOURCE_DATE_EPOCH={{ SOURCE_DATE_EPOCH }}

echo "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH"

# we create the apt user ourselves or otherwise its uid/gid will differ
# compared to the one chosen in debootstrap because of different installation
# order in comparison to the systemd users
# https://bugs.debian.org/969631
# we cannot use useradd because passwd is not Essential:yes
{{ CMD }} --variant={{ VARIANT }} --mode={{ MODE }} \
  --essential-hook='[ {{ DIST }} = oldstable ] && [ {{ VARIANT }} = - ] && echo _apt:*:100:65534::/nonexistent:/usr/sbin/nologin >> "$1"/etc/passwd || :' \
  "$(if [ {{ DIST }} = oldstable ]; then echo --merged-usr; else echo --hook-dir=./hooks/merged-usr; fi)" \
  "$(case {{ DIST }} in oldstable) echo --include=e2fsprogs,mount,tzdata,gcc-9-base ;; stable) echo --include=e2fsprogs,mount,tzdata ;; *) echo --include=base-files ;; esac)" \
  {{ DIST }} /tmp/debian-{{ DIST }}-mm.tar {{ MIRROR }}

mkdir /tmp/debian-{{ DIST }}-mm
tar --xattrs --xattrs-include='*' -C /tmp/debian-{{ DIST }}-mm -xf /tmp/debian-{{ DIST }}-mm.tar
rm /tmp/debian-{{ DIST }}-mm.tar

mkdir /tmp/debian-{{ DIST }}-debootstrap
tar --xattrs --xattrs-include='*' -C /tmp/debian-{{ DIST }}-debootstrap -xf "cache/debian-{{ DIST }}-{{ VARIANT }}.tar"

# diff cannot compare device nodes, so we use tar to do that for us and then
# delete the directory
tar -C /tmp/debian-{{ DIST }}-debootstrap -cf /tmp/dev1.tar ./dev
tar -C /tmp/debian-{{ DIST }}-mm -cf /tmp/dev2.tar ./dev
ret=0
cmp /tmp/dev1.tar /tmp/dev2.tar >&2 || ret=$?
if [ "$ret" -ne 0 ]; then
  if type diffoscope >/dev/null; then
    diffoscope /tmp/dev1.tar /tmp/dev2.tar
    exit 1
  else
    echo "no diffoscope installed" >&2
  fi
  if type base64 >/dev/null; then
    base64 /tmp/dev1.tar
    base64 /tmp/dev2.tar
    exit 1
  else
    echo "no base64 installed" >&2
  fi
  if type xxd >/dev/null; then
    xxd /tmp/dev1.tar
    xxd /tmp/dev2.tar
    exit 1
  else
    echo "no xxd installed" >&2
  fi
  exit 1
fi
rm /tmp/dev1.tar /tmp/dev2.tar
rm -r /tmp/debian-{{ DIST }}-debootstrap/dev /tmp/debian-{{ DIST }}-mm/dev

# remove downloaded deb packages
rm /tmp/debian-{{ DIST }}-debootstrap/var/cache/apt/archives/*.deb
# remove aux-cache
rm /tmp/debian-{{ DIST }}-debootstrap/var/cache/ldconfig/aux-cache
# remove logs
rm /tmp/debian-{{ DIST }}-debootstrap/var/log/dpkg.log \
  /tmp/debian-{{ DIST }}-debootstrap/var/log/bootstrap.log \
  /tmp/debian-{{ DIST }}-debootstrap/var/log/alternatives.log
# remove *-old files
rm /tmp/debian-{{ DIST }}-debootstrap/var/cache/debconf/config.dat-old \
  /tmp/debian-{{ DIST }}-mm/var/cache/debconf/config.dat-old
rm /tmp/debian-{{ DIST }}-debootstrap/var/cache/debconf/templates.dat-old \
  /tmp/debian-{{ DIST }}-mm/var/cache/debconf/templates.dat-old
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status-old \
  /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status-old
rm -f /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/diversions-old \
  /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/diversions-old
# remove dpkg files
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/available
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/cmethopt
# remove /var/lib/dpkg/arch
rm /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/arch
# since we installed packages directly from the .deb files, Priorities differ
# thus we first check for equality and then remove the files
chroot /tmp/debian-{{ DIST }}-debootstrap dpkg --list >/tmp/dpkg1
chroot /tmp/debian-{{ DIST }}-mm dpkg --list >/tmp/dpkg2
diff -u /tmp/dpkg1 /tmp/dpkg2 >&2
rm /tmp/dpkg1 /tmp/dpkg2
grep -v '^Priority: ' /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status >/tmp/status1
grep -v '^Priority: ' /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status >/tmp/status2
diff -u /tmp/status1 /tmp/status2 >&2
rm /tmp/status1 /tmp/status2
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status
# debootstrap exposes the hosts's kernel version
if [ -e /tmp/debian-{{ DIST }}-debootstrap/etc/apt/apt.conf.d/01autoremove-kernels ]; then
  rm /tmp/debian-{{ DIST }}-debootstrap/etc/apt/apt.conf.d/01autoremove-kernels
fi
if [ -e /tmp/debian-{{ DIST }}-mm/etc/apt/apt.conf.d/01autoremove-kernels ]; then
  rm /tmp/debian-{{ DIST }}-mm/etc/apt/apt.conf.d/01autoremove-kernels
fi
# clear out /run except for /run/lock
find /tmp/debian-{{ DIST }}-debootstrap/run/ -mindepth 1 -maxdepth 1 ! -name lock -print0 | xargs --no-run-if-empty -0 rm -r
# debootstrap doesn't clean apt
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/apt/lists/127.0.0.1_debian_dists_{{ DIST }}_main_binary-{{ HOSTARCH }}_Packages \
  /tmp/debian-{{ DIST }}-debootstrap/var/lib/apt/lists/127.0.0.1_debian_dists_{{ DIST }}_InRelease \
  /tmp/debian-{{ DIST }}-debootstrap/var/lib/apt/lists/127.0.0.1_debian_dists_{{ DIST }}_Release \
  /tmp/debian-{{ DIST }}-debootstrap/var/lib/apt/lists/127.0.0.1_debian_dists_{{ DIST }}_Release.gpg

if [ "{{ VARIANT }}" = "-" ]; then
  rm /tmp/debian-{{ DIST }}-debootstrap/etc/machine-id
  rm /tmp/debian-{{ DIST }}-mm/etc/machine-id
  rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/systemd/catalog/database
  rm /tmp/debian-{{ DIST }}-mm/var/lib/systemd/catalog/database

  case {{ DIST }} in oldstable | stable)
    cap=$(chroot /tmp/debian-{{ DIST }}-debootstrap /sbin/getcap /bin/ping)
    expected="/bin/ping cap_net_raw=ep"
    if [ "$cap" != "$expected" ]; then
      echo "expected bin/ping to have capabilities $expected" >&2
      echo "but debootstrap produced: $cap" >&2
      exit 1
    fi
    cap=$(chroot /tmp/debian-{{ DIST }}-mm /sbin/getcap /bin/ping)
    if [ "$cap" != "$expected" ]; then
      echo "expected bin/ping to have capabilities $expected" >&2
      echo "but mmdebstrap produced: $cap" >&2
      exit 1
    fi
    ;;
  esac
fi

rm /tmp/debian-{{ DIST }}-mm/var/cache/apt/archives/lock
rm /tmp/debian-{{ DIST }}-mm/var/lib/apt/extended_states
rm /tmp/debian-{{ DIST }}-mm/var/lib/apt/lists/lock

# the list of shells might be sorted wrongly
# /var/lib/dpkg/triggers/File might be sorted wrongly
for f in "/var/lib/dpkg/triggers/File" "/etc/shells"; do
  f1="/tmp/debian-{{ DIST }}-debootstrap/$f"
  f2="/tmp/debian-{{ DIST }}-mm/$f"
  # both chroots must have the file
  if [ ! -e "$f1" ] || [ ! -e "$f2" ]; then
    continue
  fi
  # the file must be different
  if cmp "$f1" "$f2" >&2; then
    continue
  fi
  # then sort both
  sort -o "$f1" "$f1"
  sort -o "$f2" "$f2"
done

# Because of unreproducible uids (#969631) we created the _apt user ourselves
# and because passwd is not Essential:yes we didn't use useradd. But newer
# versions of adduser and shadow will create a different /etc/shadow
if [ "{{ VARIANT }}" = "-" ] && [ "{{ DIST}}" = oldstable ]; then
  for f in shadow shadow-; do
    if grep -q '^_apt:!:' /tmp/debian-{{ DIST }}-debootstrap/etc/$f; then
      sed -i 's/^_apt:\*:\([^:]\+\):0:99999:7:::$/_apt:!:\1::::::/' /tmp/debian-{{ DIST }}-mm/etc/$f
    fi
  done
fi

for log in faillog lastlog; do
  f1="/tmp/debian-{{ DIST }}-debootstrap/var/log/$log"
  f2="/tmp/debian-{{ DIST }}-mm/var/log/$log"
  # skip cmp if file is absent in both chroots
  if [ ! -e "$f1" ] && [ ! -e "$f2" ]; then
    continue
  fi
  if ! cmp "$f1" "$f2" >&2; then
    # if the files differ, make sure they are all zeroes
    cmp -n "$(stat -c %s "$f1")" "$f1" /dev/zero >&2
    cmp -n "$(stat -c %s "$f2")" "$f2" /dev/zero >&2
    # then delete them
    rm "$f1" "$f2"
  fi
done

if [ "{{ VARIANT }}" = "-" ]; then
  # the order in which systemd and cron get installed differ and thus the order
  # of lines in /etc/group and /etc/gshadow differs
  for f in group group- gshadow gshadow-; do
    for d in mm debootstrap; do
      sort /tmp/debian-{{ DIST }}-$d/etc/$f >/tmp/debian-{{ DIST }}-$d/etc/$f.bak
      mv /tmp/debian-{{ DIST }}-$d/etc/$f.bak /tmp/debian-{{ DIST }}-$d/etc/$f
    done
  done
  # the order in which systemd and passwd get installed differ and thus
  # the order of lines in /etc/shadow and /etc/shadow- differs
  for f in shadow shadow-; do
    for d in mm debootstrap; do
      sort /tmp/debian-{{ DIST }}-$d/etc/$f >/tmp/debian-{{ DIST }}-$d/etc/$f.bak
      mv /tmp/debian-{{ DIST }}-$d/etc/$f.bak /tmp/debian-{{ DIST }}-$d/etc/$f
    done
  done
  # and since the order was different, ignore the *- files
  for f in shadow- passwd-; do
    for d in mm debootstrap; do
      rm /tmp/debian-{{ DIST }}-$d/etc/$f
    done
  done
fi

# since debootstrap 1.0.133 there is no tzdata in the buildd variant and thus
# debootstrap creates its own /etc/localtime
if [ "{{ VARIANT }}" = "buildd" ] && [ "{{ DIST }}" != "stable" ] && [ "{{ DIST }}" != "oldstable" ]; then
  [ "$(readlink /tmp/debian-{{ DIST }}-debootstrap/etc/localtime)" = /usr/share/zoneinfo/UTC ]
  rm /tmp/debian-{{ DIST }}-debootstrap/etc/localtime
fi

# starting with systemd 255 upstream dropped splitusr support and depending on
# the installation order, symlink targets are prefixed with /usr or not
# See #1060000 and #1054137
case {{ DIST }} in testing | unstable)
  for f in multi-user.target.wants/e2scrub_reap.service timers.target.wants/apt-daily-upgrade.timer timers.target.wants/apt-daily.timer timers.target.wants/e2scrub_all.timer; do
    for d in mm debootstrap; do
      [ -L "/tmp/debian-{{ DIST }}-$d/etc/systemd/system/$f" ] || continue
      oldlink="$(readlink "/tmp/debian-{{ DIST }}-$d/etc/systemd/system/$f")"
      case $oldlink in
        /usr/*) : ;;
        /*) oldlink="/usr$oldlink" ;;
        *)
          echo unexpected >&2
          exit 1
          ;;
      esac
      ln -sf "$oldlink" "/tmp/debian-{{ DIST }}-$d/etc/systemd/system/$f"
    done
  done
  ;;
esac

# check if the file content differs
diff --unified --no-dereference --recursive /tmp/debian-{{ DIST }}-debootstrap /tmp/debian-{{ DIST }}-mm >&2

# check permissions, ownership, symlink targets, modification times using tar
# directory mtimes will differ, thus we equalize them first
find /tmp/debian-{{ DIST }}-debootstrap /tmp/debian-{{ DIST }}-mm -type d -print0 | xargs -0 touch --date="@{{ SOURCE_DATE_EPOCH }}"
# debootstrap never ran apt -- fixing permissions
for d in ./var/lib/apt/lists/partial ./var/cache/apt/archives/partial; do
  unmergedPATH="$PATH$(if [ "{{ DIST }}" = oldstable ]; then echo :/bin:/sbin; fi)"
  PATH="$unmergedPATH" chroot /tmp/debian-{{ DIST }}-debootstrap chmod 0700 $d
  PATH="$unmergedPATH" chroot /tmp/debian-{{ DIST }}-debootstrap chown "$(id -u _apt):root" $d
done
tar -C /tmp/debian-{{ DIST }}-debootstrap --numeric-owner --sort=name --clamp-mtime --mtime="$(date --utc --date=@{{ SOURCE_DATE_EPOCH }} --iso-8601=seconds)" -cf /tmp/root1.tar .
tar -C /tmp/debian-{{ DIST }}-mm --numeric-owner --sort=name --clamp-mtime --mtime="$(date --utc --date=@{{ SOURCE_DATE_EPOCH }} --iso-8601=seconds)" -cf /tmp/root2.tar .
tar --full-time --verbose -tf /tmp/root1.tar >/tmp/root1.tar.list
tar --full-time --verbose -tf /tmp/root2.tar >/tmp/root2.tar.list
diff -u /tmp/root1.tar.list /tmp/root2.tar.list >&2
rm /tmp/root1.tar /tmp/root2.tar /tmp/root1.tar.list /tmp/root2.tar.list

# check if file properties (permissions, ownership, symlink names, modification time) differ
#
# we cannot use this (yet) because it cannot cope with paths that have [ or @ in them
#fmtree -c -p /tmp/debian-{{ DIST }}-debootstrap -k flags,gid,link,mode,size,time,uid | sudo fmtree -p /tmp/debian-{{ DIST }}-mm

rm -r /tmp/debian-{{ DIST }}-debootstrap /tmp/debian-{{ DIST }}-mm