#!/bin/bash

set -eu

read cur_osrelease </proc/sys/kernel/osrelease

moddir=/usr/lib/modules/$cur_osrelease
oldlink=$(readlink -m "$moddir")

if [ "${oldlink}" == /var/cache/kmods ]; then
    rm "$moddir"
    exit 0
fi

if [ -e /var/cache/kmods/osrelease ]; then
    read prev_osrelease </var/cache/kmods/osrelease
    [ "$cur_osrelease" != "$prev_osrelease" ] || exit 0
fi

[ -d "$moddir" ] || exit 0

rm -rf /var/cache/kmods

cp -a "$moddir" /var/cache/kmods
cat /proc/sys/kernel/osrelease >/var/cache/kmods/osrelease