#!/bin/bash
#
# Copyright IBM Corp. 2023
#
# s390-tools is free software; you can redistribute it and/or modify
# it under the terms of the MIT license. See LICENSE for details.
#
# zdev-to-rd.znet
#   Converts zdev configuration into the syntax of the dracut cmdline option
#   rd.znet. Only znet options with non-default values are emitted. The
#   result string occurs on stdout. It represents one device-specification for
#   the given network interface name.
#

function usage() {
    echo "usage: ${0##*/} active|persistent <network interface name>" 1>&2
    exit 1
}

[[ $# -eq 2 ]] || usage

[[ "$1" == active ]] || [[ "$1" == persistent ]] || usage

_selection="--${1}"
_ifname="$2"

while read -r _line; do
    case "$_line" in
        \#*) ;;
        \[*)
            SAVED_IFS="$IFS"
            IFS="${IFS}:]"
            # shellcheck disable=SC2086
            set -- $_line
            shift # skip "[..." prefix
            _nettype="$1"
            shift # skip nettype
            IFS="," # comma-separated subchannel list
            _subchannels="$*"
            IFS="$SAVED_IFS"
            ;;
        "online=1") ;;
        zdev:early=*) ;;
        *)
            _attrs="${_attrs},${_line}"
            ;;
    esac
done < <(chzdev --by-interface "$_ifname" "$_selection" --export - --quiet)
printf "%s,%s%s\n" "$_nettype" "$_subchannels" "$_attrs"