mender-convert/mender-convert-extract

#! /usr/bin/env bash
#
# Copyright 2020 Northern.tech AS
#
#  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.

echo "Running $(basename $0): $@"

source modules/bootstrap.sh
source modules/disk.sh

# The mender_convert_config is always used and provides all the defaults
declare -a configs=("configs/mender_convert_config")

disk_image=""
while (( "$#" )); do
  case "$1" in
    -o | --overlay)
      overlays+=("${2}")
      shift 2
      ;;
    -c | --config)
      configs+=("${2}")
      shift 2
      ;;
    -d | --disk-image)
      disk_image="${2}"
      shift 2
      ;;
    *)
      log_fatal "Sorry but the provided option is not supported: $1"
      ;;
  esac
done

if [ -z "${disk_image}" ]; then
  log_warn "Sorry, but '--disk-image' is a mandatory option"
  log_warn "See ./mender-convert --help for more information"
  exit 1
fi

if [ ! -e ${disk_image} ]; then
  log_fatal "File not found: ${disk_image}"
fi

# Note the use of %q formatting here. This is a bash feature to add
# proper quoting to the strings so that spaces and special characters
# will be treated properly.  Primarily for supporting spaces in
# pathnames and avoid splitting those into multiple parameters.
source modules/config.sh $(printf "%q " "${configs[@]}")

MKFS_VFAT="/usr/bin/mkfs.vfat"
if [ ! -f ${MKFS_VFAT} ]; then
  MKFS_VFAT="/sbin/mkfs.vfat"
fi

declare -i nr_of_parts=$(disk_get_nr_of_parts ${disk_image})

log_info "Validating disk image"

if [ ${nr_of_parts} -eq 0 ]; then
  log_fatal "Sorry, but could not find any valid partitions for: ${disk_image}"
fi

log_info "Disk parsed successfully"
log_info "NUMBER OF PARTS: ${nr_of_parts} TYPE: $(disk_get_part_value ${disk_image} 1 SCHEME)"

for ((n=1;n<=${nr_of_parts};n++)); do
  part_dst_file="work/part-${n}.fs"

  if [ "$(disk_get_part_value ${disk_image} ${n} TYPE)" == "0x8e" ]; then
    log_fatal "Detected an LVM volume group on disk. Unfortunately this is not yet supported"
  fi

  log_info "PART ${n}: SIZE: $(disk_get_part_value ${disk_image} ${n} SIZE) TYPE: $(disk_get_part_value ${disk_image} ${n} TYPE)"
  log_info "PART ${n}: extracting to ${part_dst_file}"

  disk_extract_part "${disk_image}" $(disk_get_part_value ${disk_image} ${n} START) \
    $(disk_get_part_value ${disk_image} ${n} SECTORS) ${part_dst_file}
done

# Some disk images will not have an boot partition for us to extract,
# but we do require it be present and hence we might need to generate
# a filesystem image here.
if [ ${nr_of_parts} -eq 1 ]; then
  log_info "Generating boot partition (required, does not exist in original image)"
  run_and_log_cmd "dd if=/dev/zero of=work/boot-generated.vfat count=${MENDER_BOOT_PART_SIZE_MB} bs=1M status=none"
  run_and_log_cmd "${MKFS_VFAT} work/boot-generated.vfat"
fi

# Extract boot gap, that is the area from sector 1 until first part, and
# this is done because some images might contain the bootloader embedded here
# and we might need to keep this area intact when we generate our custom
# image.
if [ "${MENDER_COPY_BOOT_GAP}" == "y" ]; then
  log_info "Extracting boot gap to work/boot-gap.bin"
  disk_extract_part "${disk_image}" \
    1 $(( $(disk_get_part_value ${disk_image} 1 START) - 1)) work/boot-gap.bin
fi