# Copyright 2021 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.

description   "Chrome OS camera service failsafe"
author        "chromium-os-dev@chromium.org"

# By default we need cros-camera to start when all the built-in camera(s) are
# probed by the kernel, so that we can report the correct static built-in camera
# info to the camera clients.  However, if any of the built-in cameras cannot be
# probed successfully (e.g. hardware failure), we still need cros-camera to run
# so users get to use external USB cameras.

# cros-camera has `respawn limit 10 60`. The failsafe is triggered when
# cros-camera fails to start after 10 retries in 60 seconds and transitions to
# `stopped`.
#
# When cros-camera is gracefully stopped, ${RESULT} is set to `ok`.  We don't
# need to trigger the failsafe in this case (e.g. user running `stop
# cros-camera`, or cros-camera stops in pre-start because system-services
# isn't ready).
start on stopped cros-camera RESULT="failed"

env FORCE_START_CROS_CAMERA_PATH="/run/camera/force_start_cros_camera"

script
  # We only want the failsafe to trigger the cros-camera service once, otherwise
  # we may end up in a crash loop and spam the syslog.
  if [ -f "${FORCE_START_CROS_CAMERA_PATH}" ]; then
    stop
    exit 0
  fi

  # We don't want to enable failsafe on test image so we can identify potential
  # issue during tests.
  if grep -q "CHROMEOS_RELEASE_TRACK=testimage-channel" "/etc/lsb-release"; then
    logger -t cros-camera-failsafe \
        "cros-camera-failsafe is disabled on test image"
    stop
    exit 0
  fi

  touch "${FORCE_START_CROS_CAMERA_PATH}"
  initctl start cros-camera
end script