#!/bin/sh

[ -f /etc/nbdtab ] || exit 0

# shellcheck disable=SC2046
set -- $(cat /proc/cmdline)
while [ $# -ge 1 ]; do
    case "$1" in
    root=nbd:*)
        arg=${1#*:}
        host=${arg%:*}
        ;;
    esac
    shift
done

[ -n "${host}" ] || exit 0

serial=$(sed -nr '/Serial/s/.*([0-9a-f]{8})/\1/p' /proc/cpuinfo)
if [ $? -ne 0 ]; then
    serial=UNKNOWN-SERIAL
fi
sed \
    -e s/@NBDHOST@/"${host}"/ \
    -e s/@SERIAL@/"${serial}"/ \
    /etc/nbdtab \
    > /run/nbdtab

mount -o bind /run/nbdtab /etc/nbdtab