udm-kexec

#!/bin/sh
# Shell script that wraps the kexec binary to support the kexec module.
#
# Copyright (C) 2021 Fabian Mastenbroek.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

set -e

BASEDIR=$(realpath "$(dirname "$0")")
UDM_VERSION=$(uname -r | sed 's/.*v\([0-9]\+\.[0-9]\+\.[0-9]\+\(-[0-9]\+\)\?\).*/\1/')
MODULE_DIR=$BASEDIR/modules/v$UDM_VERSION

# Check whether the kernel modules are already inserted
if [ ! -e /dev/kexec ]; then
    echo "Inserting kexec kernel modules..."

    # Check if the kernel version is supported
    if [ ! -d "$MODULE_DIR" ]; then
        echo "Kernel version not supported (v$UDM_VERSION)"
        echo "Make sure you have installed the latest version of udm-kernel-tools..."
        exit 1
    fi

    # We need to shim the hypervisor vectors on the UDM since its stock kernel
    # has no support for kexec at all.
    insmod "$MODULE_DIR"/kexec_mod_arm64.ko shim_hyp=1
    insmod "$MODULE_DIR"/kexec_mod.ko
fi

# The redirection library should reside in the same directory as this script.
export LD_PRELOAD=$BASEDIR/redir.so

#
exec /sbin/kexec "$@"