build_library/disk_layout_util.sh

# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

CGPT_PY="${BUILD_LIBRARY_DIR}/cgpt.py"
PARTITION_SCRIPT_PATH="usr/sbin/write_gpt.sh"

get_disk_layout_path() {
  DISK_LAYOUT_PATH="${BUILD_LIBRARY_DIR}/legacy_disk_layout.json"
  local partition_script_path=$(tempfile)
  for overlay in $(cros_overlay_list --board "$BOARD"); do
    local disk_layout="${overlay}/scripts/disk_layout.json"
    if [[ -e ${disk_layout} ]]; then
      DISK_LAYOUT_PATH=${disk_layout}
    fi
  done
}

write_partition_script() {
  local image_type=$1
  local partition_script_path=$2
  get_disk_layout_path

  sudo mkdir -p "$(dirname "${partition_script_path}")"

  sudo "${BUILD_LIBRARY_DIR}/cgpt.py" "write" \
    "${image_type}" "${DISK_LAYOUT_PATH}" "${partition_script_path}"
}

run_partition_script() {
  local outdev=$1
  local root_fs_img=$2

  local pmbr_img
  case ${ARCH} in
  arm)
    pmbr_img=/dev/zero
    ;;
  amd64|x86)
    pmbr_img=$(readlink -f /usr/share/syslinux/gptmbr.bin)
    ;;
  *)
    error "Unknown architecture: $ARCH"
    return 1
    ;;
  esac

  sudo mount -o loop "${root_fs_img}" "${root_fs_dir}"
  . "${root_fs_dir}/${PARTITION_SCRIPT_PATH}"
  write_partition_table "${outdev}" "${pmbr_img}"
  sudo umount "${root_fs_dir}"
}

get_fs_block_size() {
  get_disk_layout_path

  echo $(${CGPT_PY} readfsblocksize ${DISK_LAYOUT_PATH})
}

get_block_size() {
  get_disk_layout_path

  echo $(${CGPT_PY} readblocksize ${DISK_LAYOUT_PATH})
}

get_partition_size() {
  local image_type=$1
  local part_id=$2
  get_disk_layout_path

  echo $(${CGPT_PY} readpartsize ${image_type} ${DISK_LAYOUT_PATH} ${part_id})
}

get_filesystem_size() {
  local image_type=$1
  local part_id=$2
  get_disk_layout_path

  echo $(${CGPT_PY} readfssize ${image_type} ${DISK_LAYOUT_PATH} ${part_id})
}

get_label() {
  local image_type=$1
  local part_id=$2
  get_disk_layout_path

  echo $(${CGPT_PY} readlabel ${image_type} ${DISK_LAYOUT_PATH} ${part_id})
}

get_disk_layout_type() {
  DISK_LAYOUT_TYPE="base"
  if should_build_image ${CHROMEOS_FACTORY_INSTALL_SHIM_NAME}; then
    DISK_LAYOUT_TYPE="factory_install"
  fi
}

emit_gpt_scripts() {
  local image="$1"
  local dir="$2"

  local pack="${dir}/pack_partitions.sh"
  local unpack="${dir}/unpack_partitions.sh"
  local mount="${dir}/mount_image.sh"
  local umount="${dir}/umount_image.sh"

  local start size part x

  cat >"${unpack}" <<EOF
#!/bin/bash -eu
# File automatically generated. Do not edit.
TARGET=\${1:-}
if [[ -z \${TARGET} ]]; then
  echo "Usage: \$0 <image>" 1>&2
  echo "Example: \$0 chromiumos_image.bin" 1>&2
  exit 1
fi
set -x
$(${GPT} show "${image}" | sed -e 's/^/# /')
EOF

  for x in "${pack}" "${mount}" "${umount}"; do
    cp "${unpack}" "${x}"
  done

  while read start size part x; do
    local file="part_${part}"
    local dir="dir_${part}"
    local target='"${TARGET}"'
    local dd_args="bs=512 count=${size}"
    local start_b=$(( start * 512 ))
    local size_b=$(( size * 512 ))
    echo "dd if=${target} of=${file} ${dd_args} skip=${start}" >>"${unpack}"
    echo "dd if=${file} of=${target} ${dd_args} seek=${start} conv=notrunc" \
      >>"${pack}"
    if [[ ${size} -gt 1 ]]; then
      cat <<-EOF >>"${mount}"
mkdir -p ${dir}
sudo mount -o loop,offset=${start_b},sizelimit=${size_b} ${target} ${dir} || \
  rmdir ${dir}
EOF
      cat <<-EOF >>"${umount}"
if [[ -d ${dir} ]]; then
  sudo umount ${dir} || :
  rmdir ${dir}
fi
EOF
    fi
  done < <(${GPT} show -q "${image}")

  chmod +x "${unpack}" "${pack}" "${mount}" "${umount}"
}

build_gpt() {
  local outdev="$1"
  local rootfs_img="$2"
  local stateful_img="$3"
  local esp_img="$4"
  local oem_img="$5"

  get_disk_layout_type
  run_partition_script "${outdev}" "${rootfs_img}"

  local sudo=
  if [ ! -w "$outdev" ] ; then
    # use sudo when writing to a block device.
    sudo=sudo
  fi

  # Now populate the partitions.
  info "Copying stateful partition..."
  $sudo dd if="$stateful_img" of="$outdev" conv=notrunc bs=512 \
      seek=$(partoffset ${outdev} 1)

  info "Copying rootfs..."
  $sudo dd if="$rootfs_img" of="$outdev" conv=notrunc bs=512 \
      seek=$(partoffset ${outdev} 3)

  info "Copying EFI system partition..."
  $sudo dd if="$esp_img" of="$outdev" conv=notrunc bs=512 \
      seek=$(partoffset ${outdev} 12)

  info "Copying OEM partition..."
  $sudo dd if="$oem_img" of="$outdev" conv=notrunc bs=512 \
      seek=$(partoffset ${outdev} 8)

  # Pre-set "sucessful" bit in gpt, so we will never mark-for-death
  # a partition on an SDCard/USB stick.
  cgpt add -i 2 -S 1 "$outdev"
}

# Rebuild an image's partition table with new stateful size.
#  $1: source image filename
#  $2: source stateful partition image filename
#  $3: number of sectors to allocate to the new stateful partition
#  $4: destination image filename
# Used by dev/host/tests/mod_recovery_for_decryption.sh and
# mod_image_for_recovery.sh.
update_partition_table() {
  local src_img=$1          # source image
  local temp_state=$2       # stateful partition image
  local resized_sectors=$3  # number of sectors in resized stateful partition
  local temp_img=$4

  local temp_pmbr=$(mktemp "/tmp/pmbr.XXXXXX")
  dd if="${src_img}" of="${temp_pmbr}" bs=512 count=1 &>/dev/null
  trap "rm -rf \"${temp_pmbr}\"" EXIT

  # Set up a new partition table
  rm -f "${temp_img}"
  PARTITION_SCRIPT_PATH=$( tempfile )
  write_partition_script "recovery" "${PARTITION_SCRIPT_PATH}"
  . "${PARTITION_SCRIPT_PATH}"
  write_partition_table "${temp_img}" "${temp_pmbr}"
  echo "${PARTITION_SCRIPT_PATH}"

  local kern_a_dst_offset=$(partoffset ${temp_img} 2)
  local kern_a_src_offset=$(partoffset ${src_img} 2)
  local kern_a_count=$(partsize ${src_img} 2)

  local kern_b_dst_offset=$(partoffset ${temp_img} 4)
  local kern_b_src_offset=$(partoffset ${src_img} 4)
  local kern_b_count=$(partsize ${src_img} 4)

  local rootfs_dst_offset=$(partoffset ${temp_img} 3)
  local rootfs_src_offset=$(partoffset ${src_img} 3)
  local rootfs_count=$(partsize ${src_img} 3)

  local oem_dst_offset=$(partoffset ${temp_img} 8)
  local oem_src_offset=$(partoffset ${src_img} 8)
  local oem_count=$(partsize ${src_img} 8)

  local esp_dst_offset=$(partoffset ${temp_img} 12)
  local esp_src_offset=$(partoffset ${src_img} 12)
  local esp_count=$(partsize ${src_img} 12)

  local state_dst_offset=$(partoffset ${temp_img} 1)

  # Copy into the partition parts of the file
  dd if="${src_img}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${rootfs_dst_offset} skip=${rootfs_src_offset} count=${rootfs_count}
  dd if="${temp_state}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${state_dst_offset}
  # Copy the full kernel (i.e. with vboot sections)
  dd if="${src_img}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${kern_a_dst_offset} skip=${kern_a_src_offset} count=${kern_a_count}
  dd if="${src_img}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${kern_b_dst_offset} skip=${kern_b_src_offset} count=${kern_b_count}
  dd if="${src_img}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${oem_dst_offset} skip=${oem_src_offset} count=${oem_count}
  dd if="${src_img}" of="${temp_img}" conv=notrunc bs=512 \
    seek=${esp_dst_offset} skip=${esp_src_offset} count=${esp_count}
}