#!/bin/sh
#
# Show device mapper slave devices.  This is useful for looking up the
# /dev/sd* devices associated with a dm or multipath device.  For example:
#
# $ ls /sys/block/dm-113/slaves/
# sddt  sdjw
#

if [ "$1" = "-h" ] ; then
	echo "Show device mapper slave devices."
	exit
fi

dev="$VDEV_PATH"

# If the VDEV path is a symlink, resolve it to a real device
if [ -L "$dev" ] ; then
	dev=$(readlink "$dev")
fi

dev=$(basename "$dev")
val=""
if [ -d "/sys/class/block/$dev/slaves" ] ; then
	# ls -C: output in columns, no newlines
	val=$(ls -C "/sys/class/block/$dev/slaves")

	# ls -C will print two spaces between files; change to one space.
	val=$(echo "$val" | sed -r 's/[[:blank:]]+/ /g')
fi

echo "slaves=$val"