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falco/scripts/falco-driver-loader
2022-02-14 10:06:41 +01:00

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#!/usr/bin/env bash
#
# Copyright (C) 2021 The Falco Authors.
#
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Simple script that desperately tries to load the kernel instrumentation by
# looking for it in a bunch of ways. Convenient when running Falco inside
# a container or in other weird environments.
#
#
# Returns 1 if $cos_ver > $base_ver, 0 otherwise
#
cos_version_greater() {
if [[ $cos_ver == "${base_ver}" ]]; then
return 0
fi
#
# COS build numbers are in the format x.y.z
#
a=$(echo "${cos_ver}" | cut -d. -f1)
b=$(echo "${cos_ver}" | cut -d. -f2)
c=$(echo "${cos_ver}" | cut -d. -f3)
d=$(echo "${base_ver}" | cut -d. -f1)
e=$(echo "${base_ver}" | cut -d. -f2)
f=$(echo "${base_ver}" | cut -d. -f3)
# Test the first component
if [[ $a -gt $d ]]; then
return 1
elif [[ $d -gt $a ]]; then
return 0
fi
# Test the second component
if [[ $b -gt $e ]]; then
return 1
elif [[ $e -gt $b ]]; then
return 0
fi
# Test the third component
if [[ $c -gt $f ]]; then
return 1
elif [[ $f -gt $c ]]; then
return 0
fi
# If we get here, probably malformatted version string?
return 0
}
get_kernel_config() {
if [ -f /proc/config.gz ]; then
echo "* Found kernel config at /proc/config.gz"
KERNEL_CONFIG_PATH=/proc/config.gz
elif [ -f "/boot/config-${KERNEL_RELEASE}" ]; then
echo "* Found kernel config at /boot/config-${KERNEL_RELEASE}"
KERNEL_CONFIG_PATH=/boot/config-${KERNEL_RELEASE}
elif [ -n "${HOST_ROOT}" ] && [ -f "${HOST_ROOT}/boot/config-${KERNEL_RELEASE}" ]; then
echo "* Found kernel config at ${HOST_ROOT}/boot/config-${KERNEL_RELEASE}"
KERNEL_CONFIG_PATH="${HOST_ROOT}/boot/config-${KERNEL_RELEASE}"
elif [ -f "/usr/lib/ostree-boot/config-${KERNEL_RELEASE}" ]; then
echo "* Found kernel config at /usr/lib/ostree-boot/config-${KERNEL_RELEASE}"
KERNEL_CONFIG_PATH="/usr/lib/ostree-boot/config-${KERNEL_RELEASE}"
elif [ -n "${HOST_ROOT}" ] && [ -f "${HOST_ROOT}/usr/lib/ostree-boot/config-${KERNEL_RELEASE}" ]; then
echo "* Found kernel config at ${HOST_ROOT}/usr/lib/ostree-boot/config-${KERNEL_RELEASE}"
KERNEL_CONFIG_PATH="${HOST_ROOT}/usr/lib/ostree-boot/config-${KERNEL_RELEASE}"
elif [ -f "/lib/modules/${KERNEL_RELEASE}/config" ]; then
# This code works both for native host and containers assuming that
# Dockerfile sets up the desired symlink /lib/modules -> $HOST_ROOT/lib/modules
echo "* Found kernel config at /lib/modules/${KERNEL_RELEASE}/config"
KERNEL_CONFIG_PATH="/lib/modules/${KERNEL_RELEASE}/config"
fi
if [ -z "${KERNEL_CONFIG_PATH}" ]; then
>&2 echo "Cannot find kernel config"
exit 1
fi
if [[ "${KERNEL_CONFIG_PATH}" == *.gz ]]; then
HASH=$(zcat "${KERNEL_CONFIG_PATH}" | md5sum - | cut -d' ' -f1)
else
HASH=$(md5sum "${KERNEL_CONFIG_PATH}" | cut -d' ' -f1)
fi
}
get_target_id() {
if [ -f "${HOST_ROOT}/etc/os-release" ]; then
# freedesktop.org and systemd
# shellcheck source=/dev/null
source "${HOST_ROOT}/etc/os-release"
OS_ID=$ID
elif [ -f "${HOST_ROOT}/etc/debian_version" ]; then
# Older debian distros
# fixme > Can this happen on older Ubuntu?
OS_ID=debian
elif [ -f "${HOST_ROOT}/etc/centos-release" ]; then
# Older CentOS distros
OS_ID=centos
elif [ -f "${HOST_ROOT}/etc/VERSION" ]; then
OS_ID=minikube
else
>&2 echo "Detected an unsupported target system, please get in touch with the Falco community"
exit 1
fi
case "${OS_ID}" in
("amzn")
if [[ $VERSION_ID == "2" ]]; then
TARGET_ID="amazonlinux2"
else
TARGET_ID="amazonlinux"
fi
;;
("ubuntu")
if [[ $KERNEL_RELEASE == *"aws"* ]]; then
TARGET_ID="ubuntu-aws"
else
TARGET_ID="ubuntu-generic"
fi
;;
(*)
TARGET_ID=$(echo "${OS_ID}" | tr '[:upper:]' '[:lower:]')
;;
esac
}
load_kernel_module_compile() {
# Skip dkms on UEK hosts because it will always fail
if [[ $(uname -r) == *uek* ]]; then
>&2 echo "Skipping because the dkms install always fail (on UEK hosts)"
return
fi
if ! hash dkms >/dev/null 2>&1; then
>&2 echo "This program requires dkms"
return
fi
# Try to compile using all the available gcc versions
for CURRENT_GCC in $(which gcc) $(ls "$(dirname "$(which gcc)")"/gcc-* | grep 'gcc-[0-9]\+' | sort -n -r -k 2 -t -); do
echo "* Trying to dkms install ${DRIVER_NAME} module with GCC ${CURRENT_GCC}"
echo "#!/usr/bin/env bash" > /tmp/falco-dkms-make
echo "make CC=${CURRENT_GCC} \$@" >> /tmp/falco-dkms-make
chmod +x /tmp/falco-dkms-make
if dkms install --directive="MAKE='/tmp/falco-dkms-make'" -m "${DRIVER_NAME}" -v "${DRIVER_VERSION}" -k "${KERNEL_RELEASE}" 2>/dev/null; then
echo "* ${DRIVER_NAME} module installed in dkms"
KO_FILE="/var/lib/dkms/${DRIVER_NAME}/${DRIVER_VERSION}/${KERNEL_RELEASE}/${ARCH}/module/${DRIVER_NAME}"
if [ -f "$KO_FILE.ko" ]; then
KO_FILE="$KO_FILE.ko"
elif [ -f "$KO_FILE.ko.gz" ]; then
KO_FILE="$KO_FILE.ko.gz"
elif [ -f "$KO_FILE.ko.xz" ]; then
KO_FILE="$KO_FILE.ko.xz"
elif [ -f "$KO_FILE.ko.zst" ]; then
KO_FILE="$KO_FILE.ko.zst"
else
>&2 echo "${DRIVER_NAME} module file not found"
return
fi
echo "* ${DRIVER_NAME} module found: ${KO_FILE}"
echo "* Trying insmod"
chcon -t modules_object_t "$KO_FILE" > /dev/null 2>&1 || true
if insmod "$KO_FILE" > /dev/null 2>&1; then
echo "* Success: ${DRIVER_NAME} module found and loaded in dkms"
exit 0
else
echo "* Unable to insmod ${DRIVER_NAME} module"
fi
else
DKMS_LOG="/var/lib/dkms/${DRIVER_NAME}/${DRIVER_VERSION}/build/make.log"
if [ -f "${DKMS_LOG}" ]; then
echo "* Running dkms build failed, dumping ${DKMS_LOG} (with GCC ${CURRENT_GCC})"
cat "${DKMS_LOG}"
else
echo "* Running dkms build failed, couldn't find ${DKMS_LOG} (with GCC ${CURRENT_GCC})"
fi
fi
done
}
load_kernel_module_download() {
get_target_id
local FALCO_KERNEL_MODULE_FILENAME="${DRIVER_NAME}_${TARGET_ID}_${KERNEL_RELEASE}_${KERNEL_VERSION}.ko"
local URL
URL=$(echo "${DRIVERS_REPO}/${DRIVER_VERSION}/${FALCO_KERNEL_MODULE_FILENAME}" | sed s/+/%2B/g)
echo "* Trying to download a prebuilt ${DRIVER_NAME} module from ${URL}"
if curl -L --create-dirs "${FALCO_DRIVER_CURL_OPTIONS}" -o "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}" "${URL}"; then
echo "* Download succeeded"
chcon -t modules_object_t "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}" > /dev/null 2>&1 || true
if insmod "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}"; then
echo "* Success: ${DRIVER_NAME} module found and inserted"
exit 0
else
>&2 echo "Unable to insmod the prebuilt ${DRIVER_NAME} module"
fi
else
>&2 echo "Unable to find a prebuilt ${DRIVER_NAME} module"
return
fi
}
load_kernel_module() {
if ! hash lsmod > /dev/null 2>&1; then
>&2 echo "This program requires lsmod"
exit 1
fi
if ! hash modprobe > /dev/null 2>&1; then
>&2 echo "This program requires modprobe"
exit 1
fi
if ! hash rmmod > /dev/null 2>&1; then
>&2 echo "This program requires rmmod"
exit 1
fi
echo "* Unloading ${DRIVER_NAME} module, if present"
rmmod "${DRIVER_NAME}" 2>/dev/null
WAIT_TIME=0
KMOD_NAME=$(echo "${DRIVER_NAME}" | tr "-" "_")
while lsmod | cut -d' ' -f1 | grep -qx "${KMOD_NAME}" && [ $WAIT_TIME -lt "${MAX_RMMOD_WAIT}" ]; do
if rmmod "${DRIVER_NAME}" 2>/dev/null; then
echo "* Unloading ${DRIVER_NAME} module succeeded after ${WAIT_TIME}s"
break
fi
((++WAIT_TIME))
if (( WAIT_TIME % 5 == 0 )); then
echo "* ${DRIVER_NAME} module still loaded, waited ${WAIT_TIME}s (max wait ${MAX_RMMOD_WAIT}s)"
fi
sleep 1
done
if lsmod | cut -d' ' -f1 | grep -qx "${KMOD_NAME}" > /dev/null 2>&1; then
echo "* ${DRIVER_NAME} module seems to still be loaded, hoping the best"
exit 0
fi
echo "* Looking for a ${DRIVER_NAME} module locally (kernel ${KERNEL_RELEASE})"
get_target_id
local FALCO_KERNEL_MODULE_FILENAME="${DRIVER_NAME}_${TARGET_ID}_${KERNEL_RELEASE}_${KERNEL_VERSION}.ko"
if [ -f "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}" ]; then
echo "* Found a prebuilt ${DRIVER_NAME} module at ${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}, loading it"
chcon -t modules_object_t "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}" > /dev/null 2>&1 || true
insmod "${HOME}/.falco/${FALCO_KERNEL_MODULE_FILENAME}" && echo "* Success: ${DRIVER_NAME} module found and inserted"
exit $?
fi
if [ -n "$ENABLE_DOWNLOAD" ]; then
load_kernel_module_download
fi
if [ -n "$ENABLE_COMPILE" ]; then
load_kernel_module_compile
fi
# Last try (might load a previous driver version)
echo "* Trying to load a system ${DRIVER_NAME} module, if present"
if modprobe "${DRIVER_NAME}" > /dev/null 2>&1; then
echo "* Success: ${DRIVER_NAME} module found and loaded with modprobe"
exit 0
fi
# Not able to download a prebuilt module nor to compile one on-the-fly
>&2 echo "Consider compiling your own ${DRIVER_NAME} driver and loading it or getting in touch with the Falco community"
exit 1
}
clean_kernel_module() {
if ! hash lsmod > /dev/null 2>&1; then
>&2 echo "This program requires lsmod"
exit 1
fi
if ! hash rmmod > /dev/null 2>&1; then
>&2 echo "This program requires rmmod"
exit 1
fi
KMOD_NAME=$(echo "${DRIVER_NAME}" | tr "-" "_")
if lsmod | cut -d' ' -f1 | grep -qx "${KMOD_NAME}"; then
if rmmod "${DRIVER_NAME}" 2>/dev/null; then
echo "* Unloading ${DRIVER_NAME} module succeeded"
else
echo "* Unloading ${DRIVER_NAME} module failed"
fi
else
echo "* There is no ${DRIVER_NAME} module loaded"
fi
if ! hash dkms >/dev/null 2>&1; then
echo "* Skipping dkms remove (dkms not found)"
return
fi
DRIVER_VERSIONS=$(dkms status -m "${DRIVER_NAME}" | cut -d',' -f1 | sed -e 's/^[[:space:]]*//')
if [ -z "${DRIVER_VERSIONS}" ]; then
echo "* There is no ${DRIVER_NAME} module in dkms"
return
fi
for CURRENT_VER in ${DRIVER_VERSIONS}; do
if dkms remove "${CURRENT_VER}" --all 2>/dev/null; then
echo "* Removing ${CURRENT_VER} succeeded"
else
echo "* Removing ${CURRENT_VER} failed"
exit 1
fi
done
}
load_bpf_probe_compile() {
local BPF_KERNEL_SOURCES_URL=""
local STRIP_COMPONENTS=1
customize_kernel_build() {
if [ -n "${KERNEL_EXTRA_VERSION}" ]; then
sed -i "s/LOCALVERSION=\"\"/LOCALVERSION=\"${KERNEL_EXTRA_VERSION}\"/" .config
fi
make olddefconfig > /dev/null
make modules_prepare > /dev/null
}
if [ "${TARGET_ID}" == "cos" ]; then
echo "* COS detected (build ${BUILD_ID}), using COS kernel headers"
BPF_KERNEL_SOURCES_URL="https://storage.googleapis.com/cos-tools/${BUILD_ID}/kernel-headers.tgz"
KERNEL_EXTRA_VERSION="+"
STRIP_COMPONENTS=0
customize_kernel_build() {
pushd usr/src/* > /dev/null || exit
# Note: this overrides the KERNELDIR set while untarring the tarball
KERNELDIR=$(pwd)
export KERNELDIR
sed -i '/^#define randomized_struct_fields_start struct {$/d' include/linux/compiler-clang.h
sed -i '/^#define randomized_struct_fields_end };$/d' include/linux/compiler-clang.h
popd > /dev/null || exit
# Might need to configure our own sources depending on COS version
cos_ver=${BUILD_ID}
base_ver=11553.0.0
cos_version_greater
greater_ret=$?
if [[ greater_ret -eq 1 ]]; then
export KBUILD_EXTRA_CPPFLAGS=-DCOS_73_WORKAROUND
fi
}
fi
if [ "${TARGET_ID}" == "minikube" ]; then
MINIKUBE_VERSION="$(cat "${HOST_ROOT}/etc/VERSION")"
echo "* Minikube detected (${MINIKUBE_VERSION}), using linux kernel sources for minikube kernel"
local kernel_version
kernel_version=$(uname -r)
local -r kernel_version_major=$(echo "${kernel_version}" | cut -d. -f1)
local -r kernel_version_minor=$(echo "${kernel_version}" | cut -d. -f2)
local -r kernel_version_patch=$(echo "${kernel_version}" | cut -d. -f3)
if [ "${kernel_version_patch}" == "0" ]; then
kernel_version="${kernel_version_major}.${kernel_version_minor}"
fi
BPF_KERNEL_SOURCES_URL="http://mirrors.edge.kernel.org/pub/linux/kernel/v${kernel_version_major}.x/linux-${kernel_version}.tar.gz"
fi
if [ -n "${BPF_USE_LOCAL_KERNEL_SOURCES}" ]; then
local -r kernel_version_major=$(uname -r | cut -d. -f1)
local -r kernel_version=$(uname -r | cut -d- -f1)
KERNEL_EXTRA_VERSION="-$(uname -r | cut -d- -f2)"
echo "* Using downloaded kernel sources for kernel version ${kernel_version}..."
BPF_KERNEL_SOURCES_URL="http://mirrors.edge.kernel.org/pub/linux/kernel/v${kernel_version_major}.x/linux-${kernel_version}.tar.gz"
fi
if [ -n "${BPF_KERNEL_SOURCES_URL}" ]; then
get_kernel_config
echo "* Downloading ${BPF_KERNEL_SOURCES_URL}"
mkdir -p /tmp/kernel
cd /tmp/kernel || exit
cd "$(mktemp -d -p /tmp/kernel)" || exit
if ! curl -L -o kernel-sources.tgz --create-dirs "${FALCO_DRIVER_CURL_OPTIONS}" "${BPF_KERNEL_SOURCES_URL}"; then
>&2 echo "Unable to download the kernel sources"
return
fi
echo "* Extracting kernel sources"
mkdir kernel-sources && tar xf kernel-sources.tgz -C kernel-sources --strip-components "${STRIP_COMPONENTS}"
cd kernel-sources || exit
KERNELDIR=$(pwd)
export KERNELDIR
if [[ "${KERNEL_CONFIG_PATH}" == *.gz ]]; then
zcat "${KERNEL_CONFIG_PATH}" > .config
else
cat "${KERNEL_CONFIG_PATH}" > .config
fi
echo "* Configuring kernel"
customize_kernel_build
fi
echo "* Trying to compile the eBPF probe (${BPF_PROBE_FILENAME})"
make -C "/usr/src/${DRIVER_NAME}-${DRIVER_VERSION}/bpf" > /dev/null
mkdir -p "${HOME}/.falco"
mv "/usr/src/${DRIVER_NAME}-${DRIVER_VERSION}/bpf/probe.o" "${HOME}/.falco/${BPF_PROBE_FILENAME}"
if [ -n "${BPF_KERNEL_SOURCES_URL}" ]; then
rm -r /tmp/kernel
fi
}
load_bpf_probe_download() {
local URL
URL=$(echo "${DRIVERS_REPO}/${DRIVER_VERSION}/${BPF_PROBE_FILENAME}" | sed s/+/%2B/g)
echo "* Trying to download a prebuilt eBPF probe from ${URL}"
if ! curl -L --create-dirs "${FALCO_DRIVER_CURL_OPTIONS}" -o "${HOME}/.falco/${BPF_PROBE_FILENAME}" "${URL}"; then
>&2 echo "Unable to find a prebuilt ${DRIVER_NAME} eBPF probe"
return
fi
}
load_bpf_probe() {
echo "* Mounting debugfs"
if [ ! -d /sys/kernel/debug/tracing ]; then
mount -t debugfs nodev /sys/kernel/debug
fi
get_target_id
BPF_PROBE_FILENAME="${DRIVER_NAME}_${TARGET_ID}_${KERNEL_RELEASE}_${KERNEL_VERSION}.o"
if [ -n "$ENABLE_DOWNLOAD" ]; then
if [ -f "${HOME}/.falco/${BPF_PROBE_FILENAME}" ]; then
echo "* Skipping download, eBPF probe is already present in ${HOME}/.falco/${BPF_PROBE_FILENAME}"
else
load_bpf_probe_download
fi
fi
if [ -n "$ENABLE_COMPILE" ]; then
if [ -f "${HOME}/.falco/${BPF_PROBE_FILENAME}" ]; then
echo "* Skipping compilation, eBPF probe is already present in ${HOME}/.falco/${BPF_PROBE_FILENAME}"
else
load_bpf_probe_compile
fi
fi
if [ -f "${HOME}/.falco/${BPF_PROBE_FILENAME}" ]; then
echo "* eBPF probe located in ${HOME}/.falco/${BPF_PROBE_FILENAME}"
ln -sf "${HOME}/.falco/${BPF_PROBE_FILENAME}" "${HOME}/.falco/${DRIVER_NAME}-bpf.o" \
&& echo "* Success: eBPF probe symlinked to ${HOME}/.falco/${DRIVER_NAME}-bpf.o"
exit $?
else
>&2 echo "Unable to load the ${DRIVER_NAME} eBPF probe"
exit 1
fi
}
print_usage() {
echo ""
echo "Usage:"
echo " falco-driver-loader [driver] [options]"
echo ""
echo "Available drivers:"
echo " module kernel module (default)"
echo " bpf eBPF probe"
echo ""
echo "Options:"
echo " --help show brief help"
echo " --clean try to remove an already present driver installation"
echo " --compile try to compile the driver locally (default true)"
echo " --download try to download a prebuilt driver (default true)"
echo " --source-only skip execution and allow sourcing in another script"
echo ""
echo "Environment variables:"
echo " DRIVERS_REPO specify a different URL where to look for prebuilt Falco drivers"
echo " DRIVER_NAME specify a different name for the driver"
echo " DRIVER_INSECURE_DOWNLOAD whether you want to allow insecure downloads or not"
echo ""
echo "Versions:"
echo " Falco version ${FALCO_VERSION}"
echo " Driver version ${DRIVER_VERSION}"
echo ""
}
ARCH=$(uname -m)
KERNEL_RELEASE=$(uname -r)
if ! hash sed > /dev/null 2>&1; then
>&2 echo "This program requires sed"
exit 1
fi
KERNEL_VERSION=$(uname -v | sed 's/#\([[:digit:]]\+\).*/\1/')
DRIVERS_REPO=${DRIVERS_REPO:-"@DRIVERS_REPO@"}
if [ -n "$DRIVER_INSECURE_DOWNLOAD" ]
then
FALCO_DRIVER_CURL_OPTIONS=-fsSk
else
FALCO_DRIVER_CURL_OPTIONS=-fsS
fi
if [[ -z "$MAX_RMMOD_WAIT" ]]; then
MAX_RMMOD_WAIT=60
fi
DRIVER_VERSION="@DRIVER_VERSION@"
DRIVER_NAME=${DRIVER_NAME:-"@DRIVER_NAME@"}
FALCO_VERSION="@FALCO_VERSION@"
DRIVER="module"
if [ -v FALCO_BPF_PROBE ]; then
DRIVER="bpf"
fi
ENABLE_COMPILE=
ENABLE_DOWNLOAD=
clean=
has_args=
has_opts=
source_only=
while test $# -gt 0; do
case "$1" in
module|bpf)
if [ -n "$has_args" ]; then
>&2 echo "Only one driver per invocation"
print_usage
exit 1
else
DRIVER="$1"
has_args="true"
shift
fi
;;
-h|--help)
print_usage
exit 0
;;
--clean)
clean="true"
shift
;;
--compile)
ENABLE_COMPILE="yes"
has_opts="true"
shift
;;
--download)
ENABLE_DOWNLOAD="yes"
has_opts="true"
shift
;;
--source-only)
source_only="true"
shift
;;
--*)
>&2 echo "Unknown option: $1"
print_usage
exit 1
;;
*)
>&2 echo "Unknown driver: $1"
print_usage
exit 1
;;
esac
done
if [ -z "$has_opts" ]; then
ENABLE_COMPILE="yes"
ENABLE_DOWNLOAD="yes"
fi
if [ -z "$source_only" ]; then
echo "* Running falco-driver-loader for: falco version=${FALCO_VERSION}, driver version=${DRIVER_VERSION}"
if [ "$(id -u)" != 0 ]; then
>&2 echo "This program must be run as root (or with sudo)"
exit 1
fi
if [ -n "$clean" ]; then
if [ -n "$has_opts" ]; then
>&2 echo "Cannot use --clean with other options"
exit 1
fi
echo "* Running falco-driver-loader with: driver=$DRIVER, clean=yes"
case $DRIVER in
module)
clean_kernel_module
;;
bpf)
>&2 echo "--clean not supported for driver=bpf"
exit 1
esac
else
if ! hash curl > /dev/null 2>&1; then
>&2 echo "This program requires curl"
exit 1
fi
echo "* Running falco-driver-loader with: driver=$DRIVER, compile=${ENABLE_COMPILE:-"no"}, download=${ENABLE_DOWNLOAD:-"no"}"
case $DRIVER in
module)
load_kernel_module
;;
bpf)
load_bpf_probe
;;
esac
fi
fi