#!/bin/sh -eu

fatal() {
	printf %s\\n "Fatal: $*" >&2
	exit 1
}

[ "$#" -eq 1 ] ||
	fatal "more arguments required"

[ -n "$1" ] ||
	fatal "first argument is empty"

md_device="${1#/dev/}"

[ -d "/sys/block/$md_device" ] ||
	fatal "/sys/block/$md_device: not a directory"

[ -d "/sys/block/$md_device/md" ] ||
	fatal "/sys/block/$md_device/md: not a directory"

cd "/sys/block/$md_device/md"

for devname in dev-*; do
	[ -d "$devname" ] || break
	dev="/dev/${devname#dev-}"

	if realdev="/dev/$(devmap_name -q "$dev")"; then
		if [ ! -b "$realdev" ]; then
			printf 'Error: %s: not block device\n' "$realdev" >&2
			continue
		fi

		printf %s\\n "$realdev"
	else
		rc=$?
		[ "$rc" -ne 3 ] || printf %s\\n "$dev"
	fi
done
