trunks/trunksd.conf

# Copyright 2014 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

description     "Chromium OS trunks daemon for TPM2.0"
author          "chromium-os-dev@chromium.org"

# TODO(b/265866896): provider better abstraction by adding trunks-pre-init
# event instead
start on started boot-services and stopped cr50-result and started dbus
stop on hwsec-stop-low-level-tpm-daemon-signal
respawn


oom score -100

# These enviroment variable may be modified in the ebuild file.
# The runtime TPM selection feature would be enabled if this variable is true.
env TPM_DYNAMIC=false

# The key eviction feature would be enabled if this variable is true.
env KEY_EVICTION=false

pre-start script
  if [ "${TPM_DYNAMIC}" = true ]; then
    # Only start trunksd if TPM 2.0 device is active.
    if [ "$(tpm_version_client)" -ne 2 ]; then
      stop
      exit 0
    fi
  fi

  ERRNO=""
  READ_ERROR="99999"
  LAST_ERROR_PATH="/run/trunks/last-write-error"
  if [ -f "${LAST_ERROR_PATH}" ]; then
    ERRNO=$(cat "${LAST_ERROR_PATH}" || echo "${READ_ERROR}")
  fi
  # There is no write error from last run of trunksd.
  if [ -z "${ERRNO}" ] || [ "${ERRNO}" = "0" ]; then
    return
  fi
  if [ "${ERRNO}" == "${READ_ERROR}" ]; then
    logger -t trunksd "Error reading ${LAST_ERROR_PATH}..rebinding regardless"
  fi
  logger -t trunksd "Rebinding TPM driver upon write errno ${ERRNO}"
  DEVICE=$(find /sys/class/tpm/tpm0/device/driver/ -maxdepth 1 -type l \
      -exec basename {} \; || true)
  if [ -z "${DEVICE}" ]; then
    logger -t trunksd "Failed to get TPM device."
    return
  fi
  DRIVER=$(readlink -f /sys/class/tpm/tpm0/device/driver/ || true)
  if [ -z "${DRIVER}" ]; then
    logger -t trunksd "Failed to get TPM driver."
    return
  fi
  logger -t trunksd "Rebinding TPM drivers..."
  echo "${DEVICE}" > "${DRIVER}/unbind" || \
      logger -t trunksd "Failed to unbind driver"
  echo "${DEVICE}" > "${DRIVER}/bind" || \
      logger -t trunksd "Failed to bind driver"
  if [ "${KEY_EVICTION}" = true ]; then
    /usr/bin/systemd-tmpfiles --create --remove --clean \
      /usr/lib/tmpfiles.d/on-demand/trunks_freezer.conf
  fi
end script

expect fork

exec trunksd