login_manager/init/scripts/write-machine-info

#!/bin/sh

# Copyright 2016 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

set -e

# Determines the device serial number. On Chrome OS hardware, it's stored in VPD
# and can be read from there.
#
# For all other hardware, try to find a unique serial number from various
# sources.  We might expand this a bit more based on feedback from Chromium OS
# derivatives.  We don't currently guarantee the exact format of this either.
#
# These are example SMBIOS fields available:
# bios_date bios_vendor bios_version
# board_asset_tag board_name board_serial board_vendor board_version
# chassis_asset_tag chassis_serial chassis_type chassis_vendor chassis_version
# product_name product_serial product_uuid product_version
serial_number() {
  local serial_number

  if crossystem "mainfw_type?nonchrome"; then
    # Try the SMBIOS product serial if available.
    local smbios_pserial="/sys/devices/virtual/dmi/id/product_serial"
    if [ -r "${smbios_pserial}" ]; then
      serial_number="$(cat "${smbios_pserial}" 2>/dev/null)" || :
    fi

    if [ -z "${serial_number}" ]; then
      # Try the SMBIOS UUID if available.  QEMU can set this via -uuid.
      local smbios_puuid="/sys/devices/virtual/dmi/id/product_uuid"
      if [ -r "${smbios_puuid}" ]; then
        serial_number="$(cat "${smbios_puuid}" 2>/dev/null)" || :
      fi
    fi

    # If we couldn't find one, just use current timestamp as some sort of noise.
    if [ -z "${serial_number}" ]; then
      serial_number="$(date -u +%s)"
    fi

    # All non-Chrome OS devices get a "nonchrome" prefix.
    echo "nonchrome-${serial_number}"
  else
    # On Chrome OS hardware, read from VPD.
    vpd_get_value serial_number
  fi
}

# shellcheck disable=SC2154
true > "${MACHINE_INFO}"
chmod 0644 "${MACHINE_INFO}"

# Generate the key-value pairs we need, and capture and log errors.
MACHINE_INFO_ERR=$( {
  # If we have the Flex ID tool, output a Flex ID, or a serial number if not.
  if command -v flex_id_tool >/dev/null; then
    echo "flex_id=\"$(flex_id_tool --type=id)\""
  else
    echo "serial_number=\"$(serial_number)\""
  fi

  # Dynamic information.
  echo "customization_id=\"$(cros_config /ui help-content-id)\""
  echo "rlz_brand_code=\"$(cros_config / brand-code)\""
  echo "wpsw_cur=\"$(crossystem wpsw_cur)\""
} 2>&1 >> "${MACHINE_INFO}" )
if [ -n "${MACHINE_INFO_ERR}" ]; then
  logger -t write-machine-info "${MACHINE_INFO_ERR}"
fi