#!/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=13.0-RELEASE
ARCH=amd64
IMAGE_PATH=freebsd-zfs-$RELEASE-$(date -I).img.qcow2
IMAGE_SIZE=10G

DIST_BASE="https://download.freebsd.org/ftp/releases/$ARCH/$RELEASE"
ZPOOL=zroot

ONE_CONTEXT_PKG_URL="https://github.com/OpenNebula/addon-context-linux/releases/download/v6.2.0/one-context-6.2.0_1.txz"

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

cleanup() {
	sync || true
	umount /mnt/dev || true
	zpool export $ZPOOL || true
	mdconfig -du md0 || true
}
trap cleanup EXIT

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

env ASSUME_ALWAYS_YES=YES pkg install -y qemu-tools

# 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
disk=$(mktemp)
truncate -s 6G $disk
mdconfig -a -t vnode -f $disk -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=/mnt -m none $ZPOOL md0p2

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

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

ln -s /usr/home /mnt/home
chmod 1777 /mnt/var/tmp
chmod 1777 /mnt/tmp

# Mount allocated image.
mkdir -p /mnt/dev
mount -t devfs devfs /mnt/dev

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

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

# Configure new system.
printf '# Device\tMountpoint\tFStype\tOptions\tDump\tPass#\n' >/mnt/etc/fstab
touch /mnt/firstboot
sysrc -f /mnt/boot/loader.conf zfs_load=YES autoboot_delay=-1

sysrc -f /mnt/etc/rc.conf ntpd_enable=YES sshd_enable=YES growfs_enable=YES hostname=freebsd

cp /etc/resolv.conf /mnt/etc/resolv.conf
tzsetup -s -C /mnt UTC

cat >>/mnt/etc/ssh/sshd_config <<EOF
PermitRootLogin yes
PasswordAuthentication no
PermitEmptyPasswords no
EOF

# It doesn't appear to be necessary to use "latest", "quarterly" is new enough
#mkdir -p /mnt/usr/local/etc/pkg/repos/
#sed -es@quarterly@latest@ </mnt/etc/pkg/FreeBSD.conf >/mnt/usr/local/etc/pkg/repos/FreeBSD.conf

# freebsd-update is only supported for RELEASE
if [ "${release%-RELEASE}" != "$RELEASE" ]
then
	env PAGER=true /usr/sbin/freebsd-update \
		-b /mnt \
		--currently-running "$RELEASE" \
		--not-running-from-cron -F \
		fetch install
	rm -rf /mnt/var/db/freebsd-update/*
fi

env ASSUME_ALWAYS_YES=YES pkg -c /mnt bootstrap -f

fetch -m -o /mnt/one-context.txz "$ONE_CONTEXT_PKG_URL"
# OpenNebula has dependencies, but these are not included in the package for some reason
# https://github.com/OpenNebula/addon-context-linux/blob/40efc929487b2955e6f32643853a5cdc93c548da/targets.sh#L25
# It would be useful to see if there is an alternative to OpenNebula without so many dependencies,
# so we can run on FreeBSD base, and avoid breaking OpenNebula when the admin removes a dependency.
env ASSUME_ALWAYS_YES=YES pkg -c /mnt install sudo bash curl base64 ruby open-vm-tools-nox11 gawk virt-what one-context.txz
env ASSUME_ALWAYS_YES=YES pkg -c /mnt clean --all
rm /mnt/one-context.txz

# Remove zstd-19 again, as it would be too slow for daily use.
# But all files that were already writtne will remain zstd-19 compressed.
# zstd-19 is slow to compress but fast to read.
zfs inherit compression $ZPOOL/ROOT/default

trap : EXIT
cleanup

mkdir -p "$ARCH"
qemu-img convert -f raw -O qcow2 "$disk" "$IMAGE_PATH"
rm "$disk"

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