-CONFIG=${CONFIG:-/etc/zfs/zdev.conf}
-PATH_ID=${PATH_ID:-/lib/udev/path_id}
-AWK=${AWK:-/usr/bin/awk}
+CONFIG="${CONFIG:-/etc/zfs/zdev.conf}"
+AWK="${AWK:-/usr/bin/awk}"
+
+if [ -z "${PATH_ID}" ]; then
+ # The path_id helper became a builtin command in udev 174.
+ if [ -x '/lib/udev/path_id' ]; then
+ PATH_ID='/lib/udev/path_id'
+ else
+ PATH_ID='udevadm test-builtin path_id'
+ fi
+fi