overlay-boot/overlay-boot

#!/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"

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

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