#!/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='if [ {{ VARIANT }} = - ]; then echo _apt:*:100:65534::/nonexistent:/usr/sbin/nologin >> "$1"/etc/passwd; fi' \
	$(case {{ DIST }} in oldstable|stable) : ;; *) echo --hook-dir=./hooks/merged-usr ;; 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 dev1.tar ./dev
tar -C /tmp/debian-{{ DIST }}-mm -cf dev2.tar ./dev
ret=0
cmp dev1.tar dev2.tar || ret=$?
if [ "$ret" -ne 0 ]; then
	if type diffoscope >/dev/null; then
		diffoscope dev1.tar dev2.tar
		exit 1
	else
		echo "no diffoscope installed" >&2
	fi
	if type base64 >/dev/null; then
		base64 dev1.tar
		base64 dev2.tar
		exit 1
	else
		echo "no base64 installed" >&2
	fi
	if type xxd >/dev/null; then
		xxd dev1.tar
		xxd dev2.tar
		exit 1
	else
		echo "no xxd installed" >&2
	fi
	exit 1
fi
rm dev1.tar 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
# remove dpkg files
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/available
rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/cmethopt
# 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 > dpkg1
chroot /tmp/debian-{{ DIST }}-mm dpkg --list > dpkg2
diff -u dpkg1 dpkg2
rm dpkg1 dpkg2
grep -v '^Priority: ' /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status > status1
grep -v '^Priority: ' /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status > status2
diff -u status1 status2
rm status1 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
# who creates /run/mount?
if [ -e "/tmp/debian-{{ DIST }}-debootstrap/run/mount/utab" ]; then
	rm "/tmp/debian-{{ DIST }}-debootstrap/run/mount/utab"
fi
if [ -e "/tmp/debian-{{ DIST }}-debootstrap/run/mount" ]; then
	rmdir "/tmp/debian-{{ DIST }}-debootstrap/run/mount"
fi
# 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 }}_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

	cap=$(chroot /tmp/debian-{{ DIST }}-debootstrap /sbin/getcap /bin/ping)
	expected="/bin/ping cap_net_raw=ep"
	if [ "{{ DIST }}" = oldstable ]; then
		expected="/bin/ping = cap_net_raw+ep"
	fi
	if [ "$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
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
for f in "/tmp/debian-{{ DIST }}-debootstrap/etc/shells" "/tmp/debian-{{ DIST }}-mm/etc/shells"; do
	sort -o "$f" "$f"
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
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

# workaround for https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=917773
if ! cmp /tmp/debian-{{ DIST }}-debootstrap/etc/shadow /tmp/debian-{{ DIST }}-mm/etc/shadow; then
	echo patching /etc/shadow on {{ DIST }} {{ VARIANT }} >&2
	awk -v FS=: -v OFS=: -v SDE={{ SOURCE_DATE_EPOCH }} '{ print $1,$2,int(SDE/60/60/24),$4,$5,$6,$7,$8,$9 }' < /tmp/debian-{{ DIST }}-mm/etc/shadow > /tmp/debian-{{ DIST }}-mm/etc/shadow.bak
	cat /tmp/debian-{{ DIST }}-mm/etc/shadow.bak > /tmp/debian-{{ DIST }}-mm/etc/shadow
	rm /tmp/debian-{{ DIST }}-mm/etc/shadow.bak
else
	echo no difference for /etc/shadow on {{ DIST }} {{ VARIANT }} >&2
fi
if ! cmp /tmp/debian-{{ DIST }}-debootstrap/etc/shadow- /tmp/debian-{{ DIST }}-mm/etc/shadow-; then
	echo patching /etc/shadow- on {{ DIST }} {{ VARIANT }} >&2
	awk -v FS=: -v OFS=: -v SDE={{ SOURCE_DATE_EPOCH }} '{ print $1,$2,int(SDE/60/60/24),$4,$5,$6,$7,$8,$9 }' < /tmp/debian-{{ DIST }}-mm/etc/shadow- > /tmp/debian-{{ DIST }}-mm/etc/shadow-.bak
	cat /tmp/debian-{{ DIST }}-mm/etc/shadow-.bak > /tmp/debian-{{ DIST }}-mm/etc/shadow-
	rm /tmp/debian-{{ DIST }}-mm/etc/shadow-.bak
else
	echo no difference for /etc/shadow- on {{ DIST }} {{ VARIANT }} >&2
fi

# Because of unreproducible uids (#969631) we created the _apt user ourselves
# and because passwd is not Essential:yes we didn't use useradd. But passwd
# since 1:4.11.1+dfsg1-1 will create empty mail files, so we create it too.
# https://bugs.debian.org/1004710
if [ {{ VARIANT }} = - ]; then
	if [ -e /tmp/debian-{{ DIST }}-debootstrap/var/mail/_apt ]; then
		touch /tmp/debian-{{ DIST }}-mm/var/mail/_apt
		chmod 660 /tmp/debian-{{ DIST }}-mm/var/mail/_apt
		chown 100:8 /tmp/debian-{{ DIST }}-mm/var/mail/_apt
	fi
fi

# 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
	chroot /tmp/debian-{{ DIST }}-debootstrap chmod 0700 $d
	chroot /tmp/debian-{{ DIST }}-debootstrap chown _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
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