# Copyright 2018 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 Machine Learning service"
author          "chromium-os-dev@chromium.org"

# This daemon is started by D-Bus service activation configured in
# ml/dbus/org.chromium.MachineLearning.service and
# ml/dbus/org.chromium.MachineLearning.AdaptiveCharging.service
stop on stopping system-services
expect fork

import TASK
export TASK
instance ${TASK}

pre-start script
  logger -t "${UPSTART_JOB}" "Pre-start ml-service task=${TASK}"

  mkdir -m 0755 -p /var/lib/ml_service/metrics
  chown -R ml-service:ml-service /var/lib/ml_service

  # TASK can be "mojo_service" for a general ml-service or "adaptive_charging"
  # for adaptive charging dbus service.
  if [ "${TASK}" != "mojo_service" -a "${TASK}" != "adaptive_charging" ]; then
    logger -t "${UPSTART_JOB}" "ERROR: unknown TASK ${TASK}, quit."
    stop
    exit 0
  fi

  # Check if system-services is still running before starting ml-service.
  # This is to prevent new dbus-activated instances from getting started once
  # the system is beginning to shut down.
  if ! initctl status system-services | grep -q running; then
    logger -t "${UPSTART_JOB}" "ERROR: system services not running, quit."
    stop
    exit 0
  fi
end script

script
  if [ "${TASK}" = "mojo_service" ]; then
    # --profile=minimalistic-mountns Mount namespace with basic mounts
    #     includes /var/empty, /, /proc (RO), /dev/log, /tmp (tmpfs)
    # -b /var/lib/ml_service for ml_service metrics
    # -b /var/lib/metrics for uma metrics
    # -k /run/imageloader with MS_BIND|MS_REC to pick up any new DLC package
    #    mounts
    # We have to use nested minijail to enable correct userns set-up: the outer
    # minijail mainly does the mounting and the inner minijail set up the
    # userns. Also we have remount "/proc" by making it writable because we need
    # to write to /proc/[pid]/uid_map etc.
    # The uid/gid 20106 is for ml-service's control process.
    # The uid/gid 20177 is for bootstrapping DBus connection because DBus
    # requires the process connecting to it to have the same euid inside and
    # outside of the userns.
    exec minijail0 -n -p -l -r -v -N -i -I --uts -Kslave \
      --profile=minimalistic-mountns \
      -k 'proc,/proc,proc,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
      -k tmpfs,/var,tmpfs \
      -k tmpfs,/run,tmpfs \
      -k '/run/imageloader,/run/imageloader,none,MS_BIND|MS_REC' \
      -b /run/dbus \
      -b /var/lib/ml_service,,1 \
      -b /var/lib/metrics,,1 \
      -- /sbin/minijail0 -Kslave -U -I -v -M"0 20106 1,20177 20177 1" \
        -m"0 20106 1,20177 20177 1" \
        -k 'proc,/proc,proc,MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_RDONLY' \
        -S /usr/share/policy/ml_service-seccomp.policy \
        -- /usr/bin/ml_service --task=mojo_service

  elif [ "${TASK}" = "adaptive_charging" ]; then
    # adaptive_charging doesn't require a nested minijail.
    # TODO(alanlxl): customize seccomp to make it run in a tighter sandbox.
    exec minijail0 -e -i -n -p -l --uts -c 0 \
      --profile=minimalistic-mountns \
      -k tmpfs,/var,tmpfs \
      -k tmpfs,/run,tmpfs \
      -b /run/dbus \
      -b /var/lib/ml_service,,1 \
      -b /var/lib/metrics,,1 \
      -S /usr/share/policy/ml_service-seccomp.policy \
      -u ml-service -g ml-service \
      -- /usr/bin/ml_service --task=adaptive_charging
  fi
end script

post-start script
  local dbus_interface
  if [ "${TASK}" = "mojo_service" ]; then
    dbus_interface="org.chromium.MachineLearning"
  elif [ "${TASK}" = "adaptive_charging" ]; then
    dbus_interface="org.chromium.MachineLearning.AdaptiveCharging"
  fi

  logger -t "${UPSTART_JOB}" "Post-start ml-service task=${TASK}"
  # Wait for daemon to claim its D-Bus name before transitioning to started.
  exec minijail0 -u ml-service -g ml-service /usr/bin/gdbus \
      wait --system --timeout 15 ${dbus_interface}
end script

post-stop exec logger -t "${UPSTART_JOB}" "Post-stop ml-service task=${TASK}"