#!/bin/bash
# SPDX-License-Identifier: MIT
#
# chreipl-fcp-mpath: use multipath information to change FCP IPL target
# (C) Copyright IBM Corp. 2021
#
# Uses the following system-utilities (and shell-builtins):
#   Those necessary for sourced library:
#     - chreipl-fcp-mpath-common.sh

# Find out whether the device in environment variable ${DEVPATH} represents the
# _volume_ that we IPL'ed from. We do this by comparing its WWID to the one
# recorded in `@chreiplzfcpmp-id-file@`.
#
# Makes use of udev event environment variables:
#	DM_UUID
#	SUBSYSTEM
#	DEVPATH

# shellcheck disable=SC2034
declare -gr debug_trace_tag=11iilv
# shellcheck disable=SC1091
source '@chreiplzfcpmp-lib@' || exit 127

function id_file_read_ipl_information() {
	local -a records

	declare -g REC_WWID="" REC_BUSID="" REC_WWPN="" REC_LUN=""

	# lock file before reading ID, so we don't see any intermediate state
	id_file_lock_shared_no_create				|| return 1

	{ readarray -d "" -t -u "${ID_FILE_LOCK}" records; } 2>/dev/null \
								|| return 2
	if '@DEBUG@'; then declare -p records 1>&2; fi

	id_file_unlock_shared_no_create

	[ "${#records[@]}" = "4" ]				|| return 3
	# check that none of the array fields contains whitespace only
	[ "${records[0]/#*([[:space:]])}" != "" ]		|| return 4
	[ "${records[1]/#*([[:space:]])}" != "" ]		|| return 5
	[ "${records[2]/#*([[:space:]])}" != "" ]		|| return 6
	[ "${records[3]/#*([[:space:]])}" != "" ]		|| return 7

	REC_WWID="${records[0]}"
	REC_BUSID="${records[1]}"
	REC_WWPN="${records[2]}"
	REC_LUN="${records[3]}"
	return 0
}

id_file_read_ipl_information					|| exit 1

if [[ "${DM_UUID}" == mpath-* ]]; then
	# Assume Multipath Device Mapper Device;
	# e.g.: DEVPATH = /devices/virtual/block/dm-0
	declare sdev found=false

	for sdev in /sys/"${DEVPATH}"/slaves/sd*/device; do
		if sdev_get_wwid "${sdev}"; then
			found=true
			break
		fi
	done
	unset sdev

	"${found}"						|| exit 2

elif [ "${SUBSYSTEM}" = block ]; then
	# Assume SCSI Disk;
	# e.g.: DEVPATH = /devices/css0/0.0.0014/0.0.1700/host0/rport-0:0-0/target0:0:0/0:0:0:1074806808/block/sds

	sdev_get_wwid /sys/"${DEVPATH}"/device			|| exit 3
fi

# set by `sdev_get_wwid` and `id_file_read_ipl_information`
[ "${SDEV_WWID}" = "${REC_WWID}" ]				|| exit 4

firmware_get_ipl_information					|| exit 5
# set by `firmware_get_ipl_information` and `id_file_read_ipl_information`
[ "${IPL_BUSID}" = "${REC_BUSID}" ]				|| exit 6
[ "${IPL_WWPN}" = "${REC_WWPN}" ]				|| exit 7
[ "${IPL_LUN}" = "${REC_LUN}" ]					|| exit 8

exit 0