arc/container/scripts/arc-sensor.conf

# Copyright 2017 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   "Start sensors for a container"
author        "chromium-os-dev@chromium.org"

start on started arc-boot-continue
stop on stopped arc-boot-continue

# The following environment variable is passed when this job is
# started from arc-boot-continue.
import CONTAINER_PID

pre-start script
  {
    echo "Pre-start arc-sensor"
    set -x

    # Sensor setting.
    # Allow sending flush and frequency change commands:
    find "/sys/devices" -path '*cros-ec-*iio*' \
       \( -name 'flush' -o -name 'hwfifo_flush' -o \
          -name 'frequency' -o -name 'sampling_frequency' -o \
          -name 'hwfifo_timeout' \) \
       -exec chgrp arc-sensor {} \+ -exec chmod g+w {} \+ \
       -exec chcon -t cros_sensor_hal_sysfs {} \+

    # Allow write access to the Significant Motion Detector. Without this the
    # instance complains of not being able to listen / register to the sensor.
    find "/sys/devices" -path '*cros-ec-*activity*' \
       \( -name 'in_activity_still_change_falling_en' \) \
       -exec chgrp arc-sensor {} \+ -exec chmod g+w {} \+ \
       -exec chcon -t cros_sensor_hal_sysfs {} \+

    ring_buffer_dir="$(find /sys/devices -path '*cros-ec-ring*' -name buffer)"
    ring_dir=$(dirname "${ring_buffer_dir}")
    if [ -d "${ring_buffer_dir}" ]; then
      for name in "../trigger/current_trigger" "enable" "length"; do
         attr="${ring_buffer_dir}/${name}"
         if [ ! -e "${attr}" ]; then
           continue
         fi
         chgrp arc-sensor "${attr}"
         chmod g+rw "${attr}"
         chcon -t cros_sensor_hal_sysfs "${attr}"
      done
      # Enable all channels for ARC++, be sure the buffer is not.
      echo 0 > "${ring_buffer_dir}/enable"
      for channel in ${ring_dir}/scan_elements/*_en; do
         echo 1 > "${channel}"
      done
      ring_dev=$(cat "${ring_dir}/dev")
      # TODO(gwendal): This is fragile, needs to find a better way.
      session_manager="/sys/fs/cgroup/devices/session_manager_containers"
      echo "c ${ring_dev} r" >> "${session_manager}/android/devices.allow"
    fi
    # TODO(yusukes): The script above can be executed on start-arc-instance.

    # Copy the iio buffer device in the container.
    # TODO(lhchavez): Move this to arc-setup to avoid all the fork(2)+execve(2)
    # calls.
    if [ -d "${ring_buffer_dir}" ]; then
      ring=$(basename "${ring_dir}")
      if [ -n "${ring}" ]; then
        node_major=$(cat "${ring_dir}/dev" | cut -d: -f1)
        node_minor=$(cat "${ring_dir}/dev" | cut -d: -f2)
        # Create the iio buffer device files in the inner namespace.
        nsenter -t "${CONTAINER_PID}" --mount --pid /system/bin/mknod -m 0700 \
          "/dev/${ring}" c "${node_major}" "${node_minor}"
        # user system, group system.
        user=$(id -u android-root)
        group=$(id -g android-root)
        nsenter -t "${CONTAINER_PID}" --mount --pid /system/bin/chown \
          $((user + 1000)):$((group + 1000)) "/dev/${ring}"
        nsenter -t "${CONTAINER_PID}" --mount --pid /system/bin/restorecon \
          "/dev/${ring}"
      fi
    fi

    # Signal the container that sensor devices are ready.
    exec nsenter -t "${CONTAINER_PID}" --mount --pid -- \
      /system/bin/touch /dev/.arc_sensor_ready
  } 2>&1 | logger -t "${UPSTART_JOB}"
end script

# This job does not have script/exec stanza, so it is considered running forever
# once started. See: http://upstart.ubuntu.com/cookbook/#jobs-that-run-forever

post-stop script
  {
    echo "Post-stop arc-sensor"
    set +e -x

    ring_buffer_dir="$(find /sys/devices -path '*cros-ec-ring*' -name buffer)"
    if [ -d "${ring_buffer_dir}" ]; then
      # Disable the ring buffer, nobody will process the entries anymore.
      # Android Sensor HAL has code to disable the buffer, but it is never
      # called.
      echo 0 > "${ring_buffer_dir}/enable"
    fi
  } 2>&1 | logger -t "${UPSTART_JOB}"
end script