#!/bin/sh

# This script generates Debian images for OpenNebula.
#
# Test image locally (without network) with:
#   qemu-system-x86_64 -enable-kvm -m 1G -drive file=$IMAGE,format=qcow2

set -e
set -x

# XXX: Handle command-line arguments?
IMAGE_PATH=arch-$(date --iso-8601).img.qcow2
IMAGE_SIZE=10G
NBD_DEVICE=/dev/nbd0

ONE_CONTEXT_VERSION=5.12.0.2
ONE_CONTEXT_SOURCE_ARCHIVE="https://github.com/OpenNebula/addon-context-linux/archive/v$ONE_CONTEXT_VERSION.tar.gz"

cleanup() {
	# The order here is important.
	umount /mnt/dev/pts 2>/dev/null || true
	umount /mnt/dev/shm 2>/dev/null || true
	umount /mnt/dev 2>/dev/null || true
	umount /mnt/proc 2>/dev/null || true
	umount /mnt/run 2>/dev/null || true
	umount /mnt/sys 2>/dev/null || true
	umount /mnt/boot 2>/dev/null || true
	umount /mnt 2>/dev/null || true
	qemu-nbd --disconnect "$NBD_DEVICE" || true
}

run_root() {
	chroot /mnt /usr/bin/env \
		PATH=/sbin:/usr/sbin:/bin:/usr/bin \
		sh -c "$*"
}

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

if [ "$(lsb_release --short --id)" != "Arch" ]; then
	echo "WARNING: this script has been designed to run on Arch Linux." >&2
	echo "WARNING: Not running Arch. Giving you 5 seconds to abort." >&2
	sleep 5
fi

# Create base QCOW2 image.
qemu-img create -f qcow2 "$IMAGE_PATH" "$IMAGE_SIZE"
modprobe nbd max_part=16
qemu-nbd --connect="$NBD_DEVICE" "$IMAGE_PATH"

# Wait for qemu-nbd to settle.
sleep 1

# Don't forget to cleanup, even if the script crash.
trap cleanup EXIT

# Create partition table, format partitions.
sfdisk --no-reread "$NBD_DEVICE" <<EOF
1M,500M,L,*
,,L
EOF

mkfs.ext4 "${NBD_DEVICE}p1"
mkfs.ext4 "${NBD_DEVICE}p2"

# Mount partitions, install base OS.

mount "${NBD_DEVICE}p2" /mnt
mkdir /mnt/boot
mount "${NBD_DEVICE}p1" /mnt/boot

# Install base system.
pacstrap /mnt base base-devel openssh

mount --bind /dev /mnt/dev
mount --bind /dev/pts /mnt/dev/pts
mount --bind /dev/shm /mnt/dev/shm
mount --bind /proc /mnt/proc
mount --bind /run /mnt/run
mount --bind /sys /mnt/sys

# Required to resolve package mirror in chroot.
cp /etc/resolv.conf /mnt/etc/resolv.conf

# Initialize /etc/hosts.
cat > /mnt/etc/hosts << EOF
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

EOF

# Configure package sources and update package index.
cat > /mnt/etc/pacman.d/mirrorlist << EOF
##
## Arch Linux repository mirrorlist
## Generated on 2020-05-12
##

## Switzerland
Server = http://pkg.adfinis-sygroup.ch/archlinux/\$repo/os/\$arch
Server = https://pkg.adfinis-sygroup.ch/archlinux/\$repo/os/\$arch
Server = http://mirror.init7.net/archlinux/\$repo/os/\$arch
Server = https://mirror.init7.net/archlinux/\$repo/os/\$arch
Server = http://mirror.puzzle.ch/archlinux/\$repo/os/\$arch
Server = https://mirror.puzzle.ch/archlinux/\$repo/os/\$arch
Server = https://mirror.ungleich.ch/mirror/packages/archlinux/\$repo/os/\$arch
EOF
run_root pacman --sync --refresh --upgrade

# Guest networking is to be handled by the one-context package.
# See https://github.com/OpenNebula/addon-context-linux for details.
run_root pacman --sync curl tar
run_root curl -L "$ONE_CONTEXT_SOURCE_ARCHIVE" -o one-context.tar.gz
run_root tar xf one-context.tar.gz
run_root cp -rT addon-context-linux-${ONE_CONTEXT_VERSION}/src/ /
run_root rm -r addon-context-linux-${ONE_CONTEXT_VERSION}
run_root systemctl enable one-context.service

# Initalize base services.
run_root systemd-machine-id-setup

run_root ln -sf /usr/share/zoneinfo/UTC /etc/localtime
run_root systemctl enable systemd-timesyncd.service

# Install kernel and generate initramfs.
run_root pacman --sync linux mkinitcpio
run_rot mkinitcpio -P

# Install and configure bootloader.
run_root pacman --sync grub
run_root grub-install --target=i386-pc "${NBD_DEVICE}"
run_root grub-mkconfig -o /boot/grub/grub.cfg

# Install en configure SSH daemon.
run_root pacman --sync openssh-server

# Install haveged due to lack of entropy in ONE environment.
run_root pacman --sync haveged
run_root systemctl enable haveged.service

# Generate fstab file.
boot_uuid=$(blkid --match-tag UUID --output value "${NBD_DEVICE}p1")
root_uuid=$(blkid --match-tag UUID --output value "${NBD_DEVICE}p2")
cat >>/mnt/etc/fstab <<EOF
UUID=$boot_uuid /boot ext4 rw,relatime,data=ordered 0 2
UUID=$root_uuid /     ext4 rw,relatime,data=ordered 0 1
EOF

# Reset systemd's environment.
run_root rm -f /etc/machine-id
run_root touch /etc/machine-id
rm -f /var/lib/systemd/random-seed

# Make sure everything is written to disk before exiting.
sync