#!/bin/sh

eval $(udevadm info --export --export-prefix=ROOT_ --device-id-of-file=/ || true)

[ "$ROOT_MAJOR" -a "$ROOT_MINOR" ] || exit 0

# btrfs filesystems have bogus major/minor numbers
[ "$ROOT_MAJOR" != 0 ] || exit 0

echo 'ACTION=="add|change", SUBSYSTEM=="block", ENV{MAJOR}=="'$ROOT_MAJOR'", ENV{MINOR}=="'$ROOT_MINOR'", SYMLINK+="root"' > /etc/udev/rules.d/40-root.rules