#!/bin/sh

# This script generates FreeBSD images for OpenNebula, being heavily inspired
# from srht's FreeBSD build image definition. It assumes running on a FreeBSD host.
# ZFS installation as documented by the FreeBSD project
# https://wiki.freebsd.org/RootOnZFS/GPTZFSBoot

set -e
set -x

# XXX: Handle command-line arguments?
RELEASE=13.1-RELEASE
ARCH=amd64
IMAGE_PATH_ZFS=freebsd-zfs-$RELEASE-$(date -I).img.qcow2
IMAGE_PATH_UFS=freebsd-ufs-$RELEASE-$(date -I).img.qcow2
IMAGE_SIZE=10G

DIST_BASE="https://download.freebsd.org/ftp/releases/$ARCH/$RELEASE"
CLOUDSETUP_COMMIT=4ac15b8647d5525048c5faa5fd4b28491905d000
CLOUDSETUP_URL="https://git.sr.ht/~jornane/cloudsetup/archive/$CLOUDSETUP_COMMIT.tar.gz"
ZPOOL=zroot
ZPOOL_TMP="zinstalling"

ZFSTARGET="$(mktemp -d /var/tmp/zfsbuild.XXXXX)"
UFSTARGET="$(mktemp -d /var/tmp/ufsbuild.XXXXX)"
CLOUDSETUP_WORK="$(mktemp -d /var/tmp/cloudsetup.XXXXX)"

if zpool list -Ho name $ZPOOL_TMP 2>/dev/null; then
	echo "The pool $ZPOOL_TMP is already imported." >&2
	exit 1
fi

cleanup() {
	sync ||:
	umount "$UFSTARGET/dev" ||:
	umount "$UFSTARGET/tmp" ||:
	umount "$UFSTARGET/var/tmp" ||:
	umount "$UFSTARGET" ||:
	zpool export $ZPOOL_TMP ||:
	mdconfig -du md0 ||:
	mdconfig -du md1 ||:
	rm -rf "$CLOUDSETUP_WORK" ||:
	rmdir "$ZFSTARGET" ||:
	rmdir "$UFSTARGET" ||:
}
trap cleanup EXIT

if [ "$(whoami)" != 'root' ]; then
	echo "This script must be run as root." >&2
	exit 1
fi

if ! command -v rsync >/dev/null
then
	env ASSUME_ALWAYS_YES=YES pkg install -y rsync
fi
if ! command -v qemu-img >/dev/null
then
	env ASSUME_ALWAYS_YES=YES pkg install -y qemu-tools
fi

fetch -qo- "$CLOUDSETUP_URL" | tar -C "$CLOUDSETUP_WORK" --strip-components 1 -xzf-

ufsdisk=$(mktemp /var/tmp/ufsdisk.XXXXX)
truncate -s 6G $ufsdisk
mdconfig -a -t vnode -f $ufsdisk -u md1
gpart create -s gpt /dev/md1
gpart add -t freebsd-boot -l bootfs -b 40 -s 512K md1
gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 md1
gpart add -t freebsd-ufs -l rootfs -b 1M -s 5G md1
newfs -U /dev/md1p2

# Mount allocated image.
mount /dev/md1p2 "$UFSTARGET"

# Allocate and partition/format disk image.
# We use "legacy boot", aka BIOS boot
# Preferably, we'd use EFI boot here, check the FreeBSD wiki link in the header
# to see how to make that change, but make the EFI partition larger
zfsdisk=$(mktemp /var/tmp/zfsdisk.XXXXX)
truncate -s 6G $zfsdisk
mdconfig -a -t vnode -f $zfsdisk -u md0
gpart create -s gpt /dev/md0
gpart add -t freebsd-boot -l bootfs -b 40 -s 512K md0
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 md0
gpart add -t freebsd-zfs -l zfs0 -b 1M -s 5G md0
zpool create -O compression=on -o ashift=12 -o altroot="$ZFSTARGET" -m none -t $ZPOOL_TMP $ZPOOL md0p2

zfs create -o mountpoint=none                                  $ZPOOL_TMP/ROOT
# We set zstd-19 so our image will become smaller, at the cost of a longer build time.
# At the end of the process, we disable zstd-19 again using zfs inherit compression,
# but all files already written will remain zstd-19 compressed
zfs create -o mountpoint=/ -o canmount=noauto                  $ZPOOL_TMP/ROOT/default
mount -t zfs $ZPOOL_TMP/ROOT/default "$ZFSTARGET"
zpool set bootfs=$ZPOOL_TMP/ROOT/default $ZPOOL_TMP

zfs create -o mountpoint=/tmp  -o exec=on      -o setuid=off   $ZPOOL_TMP/tmp
zfs create -o canmount=off -o mountpoint=/usr                  $ZPOOL_TMP/usr
zfs create                                                     $ZPOOL_TMP/usr/home
zfs create                     -o exec=off     -o setuid=off   $ZPOOL_TMP/usr/src
zfs create -o mountpoint=/usr/ports            -o setuid=off   $ZPOOL_TMP/usr/ports
zfs create -o canmount=off -o mountpoint=/var                  $ZPOOL_TMP/var
zfs create                     -o exec=off     -o setuid=off   $ZPOOL_TMP/var/audit
zfs create                     -o exec=off     -o setuid=off   $ZPOOL_TMP/var/crash
zfs create                     -o exec=off     -o setuid=off   $ZPOOL_TMP/var/log
zfs create -o atime=on         -o exec=off     -o setuid=off   $ZPOOL_TMP/var/mail
zfs create                     -o exec=on      -o setuid=off   $ZPOOL_TMP/var/tmp

ln -s /usr/home "$ZFSTARGET/home"
chmod 1777 "$ZFSTARGET/var/tmp"
chmod 1777 "$ZFSTARGET/tmp"

# Mount dev in chroot
mkdir -p "$UFSTARGET/dev"
mount -t devfs devfs "$UFSTARGET/dev"

# Download and extract base system.
dist_files="kernel.txz base.txz"
dist_dir="/usr/freebsd-dist/$ARCH/$RELEASE"

mkdir -p "$dist_dir" "$UFSTARGET"
for f in $dist_files
do
	fetch -m -o "$dist_dir/$f" "$DIST_BASE/$f"
	tar -C "$UFSTARGET" -xJf "$dist_dir/$f"
done

# Avoid writing temporary files while building
mount_nullfs /tmp "$UFSTARGET/tmp"
mount_nullfs /var/tmp "$UFSTARGET/var/tmp"

# Install the first-boot script that configures the network and ssh key
make -C "$CLOUDSETUP_WORK/" PREFIX="$UFSTARGET/usr/local" install

# Configure new system.
printf '# Device\tMountpoint\tFStype\tOptions\t\tDump\tPass#\n' >"$UFSTARGET/etc/fstab"
touch "$UFSTARGET/firstboot"
sysrc -f "$UFSTARGET/boot/loader.conf" \
	zfs_load=YES \
	autoboot_delay=-1 \

sysrc -f "$UFSTARGET/etc/rc.conf" \
	ntpd_enable=YES \
	sshd_enable=YES \
	growfs_enable=YES \
	hostname=freebsd \
	firstboot_cloudsetup_enable=YES \

# The resolv.conf file is written by firstboot_cloudsetup
#cp /etc/resolv.conf "$UFSTARGET/etc/resolv.conf"

tzsetup -s -C "$UFSTARGET" UTC

cat >>"$UFSTARGET/etc/ssh/sshd_config" <<EOF
PermitRootLogin yes
PasswordAuthentication no
PermitEmptyPasswords no
EOF

# freebsd-update is only supported for RELEASE
if printf %s "$RELEASE" | grep -q '.-RELEASE$'
then
	env PAGER=true /usr/sbin/freebsd-update \
		-b "$UFSTARGET" \
		--currently-running "$RELEASE" \
		--not-running-from-cron -F \
		fetch install
fi
rm -rf "$UFSTARGET/var/db/freebsd-update/"* ||:

# Set zstd-19 compression, copy all data to the pool, and then set compression to default again
# This will make the base image smaller, at the cost of taking longer to generate, as zstd-19 is slow to write
# Therefore, afterwards we restore compression to default, so written files stay zstd-19, which is fast to read,
# but files written by the user afterwards will be written with the default compression algorihtm.
zfs set compression=zstd-19 $ZPOOL_TMP/ROOT/default
umount "$UFSTARGET/dev" "$UFSTARGET/tmp" "$UFSTARGET/var/tmp"
rsync -aH --fileflags --inplace "$UFSTARGET/." "$ZFSTARGET"
sysrc -f "$UFSTARGET/boot/loader.conf" -x zfs_load
printf '%s\t%s\t\t%s\t%s\t%s\t%s\n' /dev/gpt/rootfs / ufs rw,noatime 1 1 >>"$UFSTARGET/etc/fstab"
sync ||:
zfs inherit compression $ZPOOL_TMP/ROOT/default

trap : EXIT
cleanup

mkdir -p "$ARCH"
qemu-img convert -f raw -O qcow2 "$zfsdisk" "$ARCH/$IMAGE_PATH_ZFS"
qemu-img convert -f raw -O qcow2 "$ufsdisk" "$ARCH/$IMAGE_PATH_UFS"
rm "$zfsdisk" "$ufsdisk"

# Filesystem will be enlarged by growfs(7) on next startup
qemu-img resize "$ARCH/$IMAGE_PATH_ZFS" "$IMAGE_SIZE"
qemu-img resize "$ARCH/$IMAGE_PATH_UFS" "$IMAGE_SIZE"