dlcservice/dlcservice.conf

# 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     "Downloadable content service daemon"
author          "chromium-os-dev@chromium.org"

start on starting system-services
stop on stopping system-services
expect fork
respawn
respawn limit 3 10  # if the job respawns 3 times in 10 seconds, stop trying.

pre-start script
  # Initialize:
  # -The DLC image directory.
  # -The DLC metadata directory.
  for dlc_path in "/var/cache/dlc" "/var/lib/dlcservice"
  do
    mkdir -p "${dlc_path}"
    chmod -R u+rwX,go+rX,go-w "${dlc_path}"
    chown -R dlcservice:dlcservice "${dlc_path}"
  done
  # -The DLC preload directory.
  # The preload directory will only be created for test images.
  DLC_PRELOAD_PATH="/var/cache/dlc-images"
  if [ -d "${DLC_PRELOAD_PATH}" ]; then
    chown -R dlcservice:dlcservice "${DLC_PRELOAD_PATH}"
  fi
end script

script
  set --
  DLC_PRELOAD_PATH="/var/cache/dlc-images"
  if [ -d "${DLC_PRELOAD_PATH}" ]; then
    set -- "$@" -b "${DLC_PRELOAD_PATH}"
  fi
  # -i Exit immediately after fork.
  # -u Run as dlcservice user.
  # -g Run as dlcservice group.
  # -G Inherit supplementary groups from new uid.
  # -n prevents the executable from gaining new privileges.
  # minimal mount namespace without /dev because we want real /dev.
  # tmpfs on /run, /var, /sys so we can create mounts under them.
  # -b /run/dbus for system dbus socket.
  # -b /var/lib/metrics Mount with write permissions for uma metrics.
  # -b /var/lib/dlcservice with write for preferences.
  # -b /var/cache/dlc write for dlc images.
  # -b /var/cache/dlc-images for preloaded dlc images.
  # -b /sys/block, -b /sys/devices, -b /dev for boot slot detection.
  # -b /run/systemd/journal/dev-log for logging.
  # -S Set seccomp filter using dlcservice-seccomp.policy.
  exec minijail0 -i -u dlcservice -g dlcservice -G -n \
    --profile=minimalistic-mountns-nodev \
    -k 'tmpfs,/run,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
    -k 'tmpfs,/var,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
    -k 'tmpfs,/sys,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
    -b /run/dbus \
    -b /var/lib/metrics,,1 \
    -b /var/lib/dlcservice,,1 \
    -b /var/cache/dlc,,1 \
    -b /sys/block \
    -b /sys/devices \
    -b /dev \
    -b /run/systemd/journal/dev-log \
    "$@" \
    -S /usr/share/policy/dlcservice-seccomp.policy /usr/sbin/dlcservice
end script