sbin/chromeos-setgoodfirmware

#!/bin/sh
# Copyright 2017 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script is expected to run by update_engine on each reboot (usually after
# 60s) via chromeos-setgoodkernel. Same as chromeos-setgoodkernel, this script
# will mark active firmware as the "good one".
# For vboot1 systems always taking RW_SECTION_A as default firmware, this must
# be done by "cloning active to the other RW section".
# For vboot2 systems, just set fw_result to success and zero fw_try_count.

COMPLETE_EVENT="chromeos-setgoodfirmware"
BOARD_SCRIPT="/usr/sbin/board-setgoodfirmware"

# Prints arguments as error messages and aborts.
# Usage: die <messages>
die() {
  echo "ERROR: $0: $*" >&2
  exit 1
}

info() {
  echo "INFO: $0: $*"
}

# Clones an AP firmware slot to another one using flashrom.
# Usage: clone_firmware <from_slot> <to_slot>
clone_firmware() {
  local from="$1" to="$2"
  local image rw_section
  image="$(mktemp)"
  rw_section="$(mktemp)"
  # shellcheck disable=SC2064
  trap "rm -f ${image} ${rw_section}" EXIT

  echo "Cloning firmware ${from} to ${to}..."
  flashrom -p host -r "${image}" -i FMAP \
    -i "RW_SECTION_${from}:${rw_section}" 2>&1 || \
    die "Fail to read RW firmware slot ${from}."
  flashrom -p host -w "${image}" --noverify \
    -i "RW_SECTION_${to}:${rw_section}" 2>&1 || \
    die "Fail to write RW firmware slot ${to}."

  # The main script may do "exec ${BOARD_SCRIPT} so trap of EXIT may not work
  # outside this function.
  trap - EXIT
  rm -f "${image}" "${rw_section}"
}

# Checks if the system has EC. crbug.com/733014: `crossystem ecfw_act` will
# return 'RO' on x86 Chromeboxes so we have to check EC availability again
# before starting the update plan.
has_ec() {
  mosys ec info -s name >/dev/null 2>&1
}

# Clones "good" (active) firmware to other slot.
# Usage: clone_good_firmware
clone_good_firmware() {
  local mainfw_act
  mainfw_act="$(crossystem mainfw_act)"
  case "${mainfw_act}" in
    A)
      clone_firmware A B
      ;;
    B)
      clone_firmware B A
      ;;
    *)
      die "Abnormal active firmware: ${mainfw_act}."
      ;;
  esac

  if [ "$(crossystem ecfw_act || true)" = "RO" ] && has_ec; then
    # TODO(hungte) We need to handle one special case in future: user boot with
    # recovery button pressed and then never hard-reset device, and then EC will
    # always be in RO until we rewrite the EC firmware (i.e., next startup
    # update).
    echo "EC was boot by RO and may need an update/recovery."
    crossystem fwupdate_tries=6
  fi
}

# Notifies Upstart jobs that we have finished setting a good firmware.
# Usage: emit_complete_event
emit_complete_event() {
  initctl emit -n "${COMPLETE_EVENT}" || true
}

# Main entry.
main() {
  case "$(crossystem fw_vboot2)" in
    1)
      crossystem fw_result=success fw_try_count=0 ||
        die "Fail to set good kernel with vboot2 firmware."
      emit_complete_event
      info "Active vboot2 firmware set as good firmware."
      ;;

    0)
      # Vboot1, copy main firmware to the spare slot.
      clone_good_firmware
      crossystem fwb_tries=0
      emit_complete_event
      info "Active vboot1 firmware set as good firmware."
      ;;

    *)
      die "Unknown vboot firmware type."
      ;;
  esac
  if [ -x "${BOARD_SCRIPT}" ]; then
    info "Running board script ${BOARD_SCRIPT}..."
    exec "${BOARD_SCRIPT}"
  fi
}
main "$@"