ceinit

#!/bin/sh
#
# This file is part of Celestial (https://github.com/OpenFogStack/celestial).
# Copyright (c) 2024 Tobias Pfandzelter, The OpenFogStack Team.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#

# see https://github.com/firecracker-microvm/firecracker/discussions/3061
# in addition to the base file system, here we mount our overlay
# overlay_root is a kernel parameter
# check that $overlay_root is set and /dev/$overlay_root exists
# if not, give an error

if [ -z "$overlay_root" ] ||
    [ ! -e "/dev/$overlay_root" ] && [ ! -d "/dev/$overlay_root" ]; then
    echo "FATAL: Overlay root given as $overlay_root but /dev/$overlay_root does not exist"
    echo "Known devices:"
    ls /dev
    exit 1
fi

echo "Initializing overlay root /dev/$overlay_root"

/bin/mount -t ext4 "/dev/$overlay_root" /overlay
mkdir -p /overlay/root /overlay/work

/bin/mount \
    -o noatime,lowerdir=/,upperdir=/overlay/root,workdir=/overlay/work \
    -t overlay "overlayfs:/overlay/root" /mnt

pivot_root /mnt /mnt/rom

./sbin/fcinit

exec /sbin/init