camera/hal_adapter/init/cros-camera.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 Chrome OS camera service"
author        "chromium-os-dev@chromium.org"

start on starting system-services or usbcam-device-added or mipicam-device-added
stop on stopping system-services
expect fork
respawn
respawn limit 10 60

env SECCOMP_POLICY_FILE=/usr/share/policy/cros-camera.policy
env UVC_HWTIMESTAMPS_FILE=/sys/module/uvcvideo/parameters/hwtimestamps
env UVC_CLOCK_FILE=/sys/module/uvcvideo/parameters/clock
env SERVER_TOKEN_DIR=/run/camera_tokens/server

# Don't respawn too aggressively so kernel has some room to breathe and
# initialize cameras.
env RESPAWN_DELAY=5

# cros_camera_service provides camera service to both Chrome and ARC++:
# Chrome hosts the CameraHalDispatcher Mojo proxy; cros_camera_service forks a
# child process to host the camera HAL adapter and registers to
# CameraHalDispatcher Mojo proxy.  Camera clients can then ask
# CameraHalDispatcher Mojo proxy to get the handle to connect to the camera HAL
# adapter.

pre-start script
  # If the usbcam-device-added event is triggered too early, the environment
  # such as the /run/camera directory might not be ready yet. Ignore the usbcam
  # event in that case and wait "starting system-services" event to start
  # cros-camera again when the environment is ready.
  if [ "${UPSTART_EVENTS}" = "usbcam-device-added" ] && \
     ! status system-services | grep -q "start/running"; then
    logger -t cros-camera "system-services hasn't started yet, ignore."
    stop
    exit 0
  fi

  # Run the board-specific setup hooks, if any.
  sh /etc/camera/setup-hooks.sh || true
  [ -e "${UVC_HWTIMESTAMPS_FILE}" ] && echo 1 > "${UVC_HWTIMESTAMPS_FILE}" || true
  if [ "$(cros_config /camera clock)" = "boottime" ]; then
    printf "boottime" > "${UVC_CLOCK_FILE}" || true
  fi

  # Ensure that the server token directory exists so that it can be bind-mounted
  # into the minijail that cros-camera runs in.
  sudo -u chronos -g arc-camera mkdir -m 770 -p -- "${SERVER_TOKEN_DIR}"
end script

post-start script
  # Run the board-specific hooks, if any.
  sh /etc/camera/post-start-hooks.sh || true
end script

post-stop script
  goal=$(status cros-camera | awk '{split($2, a, "/"); print a[1]}')
  if [ "${goal}" = "start" ]; then
    # Sleep only if it's respawning, so we don't need to wait when doing `stop
    # cros-camera` in tests or manually.
    sleep "${RESPAWN_DELAY}"
  fi
end script

# Need -G to be in video group to access /dev/video*.
# Need access to original network namespace for udev (no -e), which passes
# uevents via netlink socket.
# Need access to /proc, /sys, /dev to perform USB enumeration.
# Need access to /var/cache/camera to read camera parameters.
# Need access to /var/lib/timezone to read correct timezone.
# Need access to /run/systemd/journal for logging (crbug.com/932761)
# Need read access to /run/chromeos-config/v1 for access to chromeos-config.
# Need (writable) access to /dev/shm to share memory with Android.
# Need (writable) access to /sys/kernel/debug/tracing to log events.
# Need (writable) access to /var/lib/metrics to log metrics.
# Need (writable) access to /run/dbus for DBus communications.
# Set RLIMIT_NICE(=13) to 40,40
exec minijail0 -i -u arc-camera -g arc-camera -G \
    -N -p -r -l -t \
    -v -P /mnt/empty -b / -b /proc -b /sys -b /dev \
    -k 'tmpfs,/var,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC' -b /var/cache/camera \
    -b /var/lib/timezone -b /dev/shm,,1 -b /sys/kernel/debug \
    -b /sys/kernel/debug/tracing,,1 \
    -k 'tmpfs,/run,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
    -b /run/camera,,1 -b "${SERVER_TOKEN_DIR}" -b /run/systemd/journal \
    -b /run/udev/data -b /run/chromeos-config/v1 \
    -b /var/lib/metrics,,1 -b /run/dbus/ \
    -R 13,40,40 \
    -n -S "${SECCOMP_POLICY_FILE}" \
    -- /usr/bin/cros_camera_service