reset_uki_cmdline.sh

#!/bin/bash
#
# Copyright 2026 Google LLC
#
# 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.
#

SCRIPT_ROOT="$(dirname "$(readlink -f "$0")")"
# shellcheck source=build_library/build_common.sh
. "${SCRIPT_ROOT}/build_library/build_common.sh" || exit 1

DEFINE_string image_path "" \
  "Path to image to reset UKI cmdline on"
DEFINE_string board "${DEFAULT_BOARD}" \
  "Board of the input image"

FLAGS "$@" || exit 1

eval set -- "${FLAGS_ARGV}"

switch_to_strict_mode

# N.B.  Ordering matters for some of the libraries below, because
# some of the files contain initialization used by later files.
# shellcheck source=build_library/board_options.sh
. "${BUILD_LIBRARY_DIR}/board_options.sh" || exit 1
# shellcheck source=build_library/disk_layout_util.sh
. "${BUILD_LIBRARY_DIR}/disk_layout_util.sh" || exit 1
# shellcheck source=build_library/mount_gpt_util.sh
. "${BUILD_LIBRARY_DIR}/mount_gpt_util.sh" || exit 1
# shellcheck source=build_library/build_image_util.sh
. "${BUILD_LIBRARY_DIR}/build_image_util.sh" || exit 1
# shellcheck source=build_library/base_image_util.sh
. "${BUILD_LIBRARY_DIR}/base_image_util.sh" || exit 1
# shellcheck source=build_library/dev_image_util.sh
. "${BUILD_LIBRARY_DIR}/dev_image_util.sh" || exit 1
# shellcheck source=build_library/test_image_util.sh
. "${BUILD_LIBRARY_DIR}/test_image_util.sh" || exit 1
# shellcheck source=build_library/selinux_util.sh
. "${BUILD_LIBRARY_DIR}/selinux_util.sh" || exit 1

reset_cmdline() {
  local image=$1
  local kernel=$2
  local tmpdir="$(mktemp -d)"
  local root_fs_dir="${tmpdir}/rootfs"
  local stateful_fs_dir="${tmpdir}/stateful"
  local esp_fs_dir="${tmpdir}/esp"
  local vmlinux="/build/${BOARD}/usr/src/linux/build/vmlinux"

  trap "check_full_disk ; unmount_image ; rm -r ${tmpdir}" EXIT
  mount_image "${image}" "${root_fs_dir}" "${stateful_fs_dir}" \
    "${esp_fs_dir}" --safe

  sudo mv "${esp_fs_dir}/${kernel}" "${esp_fs_dir}/efi/boot/bootx64.efi"

  unmount_image
  trap - EXIT

  PATH=$PATH:/sbin cos_kernel_args --vmlinux "${vmlinux}" \
    sed --command "s|.*||g" "${image}"

  trap "check_full_disk ; unmount_image ; rm -r ${tmpdir}" EXIT
  mount_image "${image}" "${root_fs_dir}" "${stateful_fs_dir}" \
    "${esp_fs_dir}" --safe

  sudo mv "${esp_fs_dir}/efi/boot/bootx64.efi" "${esp_fs_dir}/${kernel}"
  sudo cp "${esp_fs_dir}/efi/boot/shimx64.efi" \
    "${esp_fs_dir}/efi/boot/bootx64.efi"

  unmount_image
  trap - EXIT
}

main() {
  local image="${FLAGS_image_path}"
  if [[ -z "${image}" ]]; then
    error "Must set --image_path flag"
    exit 1
  fi

  info "Entering reset_uki_cmdline.sh $*"

  reset_cmdline "${image}" "/syslinux/vmlinuz.A"
  reset_cmdline "${image}" "/syslinux/vmlinuz.B"
}

main "$@"