#!/bin/sh
#
# This boot scripts runs a service subhost as defined by the
# configuration file named on the command line.
# See "man overlay-boot" for details.

set -x
PROGRAMDIR="$(dirname $(realpath $0))"
. $PROGRAMDIR/functions

subhost_name $1

if [ -z "$UNSHARED" ] ; then
    if [ ! -r /run/netns/$NAME ] ; then
	ip netns add $NAME
	ip netns exec $NAME ip link set lo up || exit 1
    fi
    exec env UNSHARED=yes unshare -m $0 $@ > $LOG 2>&1 &
    echo "Logging to $LOG" >&2
    exit 0
fi

subhost_config
setup_veth_cables $NAME $CABLES
setup_overlay "$NAME" "$LIVE" "$LOWER" "$UPPER" "$WORK"
setup_cgroup2_accounting "$NAME" "$$"

exithandler() {
    ip netns del $NAME
    [ "$UPPER" != "$LIVE" ] && umount -R "$LIVE"
}
trap "exithandler" 0

# This process has an unshared mount namespace, so we unmount almost
# everything before chroot. Exceptions are: $LIVE and anything mounted
# below that, "/run/netns/$NAME" and its parent paths (incidentally
# including "/" as well) and "/proc".
sort -rk2,2 < /proc/mounts | while read D P A2 ; do
    beginswith "$P" "$LIVE" && continue
    beginswith "$P" "$(realpath $LIVE)" && continue
    beginswith "/run/netns/$NAME" "$P" && continue
    [ "$P" = /proc ] && continue
    umount "$P"
done

echo "Starting $NAME"
env CONFIG="$CONFIG" $INIT | \
    unshare -fp --mount-proc -i -u \
	    ip netns exec $NAME chroot $LIVE /bin/sh
echo "Exited $NAME"