arc/data-snapshotd/init/arc-data-snapshotd.conf

# Copyright 2020 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 arc-data-snapshotd daemon in Chrome OS."
author          "chromium-os-dev@chromium.org"

# Chrome browser manages a lifetime of arc-data-snapshotd daemon via upstart.
# The daemon is responsible for ARC snapshot of data/ directory management.
stop on stopping ui

# Killable for memory leaks.
oom score -100

respawn
# If the job respawns 3 times in 10 seconds, stop trying.
respawn limit 3 10

pre-start script
  SNAPSHOT_DIR=/mnt/stateful_partition/unencrypted/arc-data-snapshot
  mkdir -p -m 755 "${SNAPSHOT_DIR}"
  chown -R arc-data-snapshotd:arc-data-snapshotd "${SNAPSHOT_DIR}"
end script

# Used jailing parameters:
#   -e: new network namespace;
#   -l: new IPC namespace;
#   -n: the no_new_privs bit;
#   -p: new PID namespace;
#   -t: a new tmpfs filesystem for /tmp;
#   -v: new VFS namespace;
#   --uts: new UTS/hostname namespace;
#   -u, -g: user account and group;
#   --profile: minimalistic mount namespace;
#   -k /run: a new tmpfs filesystem for /run, with the subsequent parameters
#       mounting specific files into this directory;
#   -b /run/dbus: shared socket file for talking with the D-Bus daemon;
#   -b /mnt/stateful_partition/unencrypted/arc-data-snapshot: arc data snapshot
#      directory;
#   -b /opt/google/containers/android/rootfs/android-data: bind mounted
#      android-data directory;
#   -S: apply seccomp filters.
script
  logger -t "${UPSTART_JOB}" "Start arc-data-snapshotd"
  set -x

  exec minijail0 -e -l -n -p -t -v --uts \
    -u arc-data-snapshotd -g arc-data-snapshotd \
    --profile=minimalistic-mountns \
    -k 'tmpfs,/run,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=10M' \
    -b /run/dbus \
    -b /mnt/stateful_partition/unencrypted/arc-data-snapshot \
    -b /opt/google/containers/android/rootfs/android-data \
    -S /usr/share/policy/arc-data-snapshotd-seccomp.policy \
    -- /usr/bin/arc-data-snapshotd
end script

# Wait for daemon to claim its D-Bus name before transitioning to started.
post-start exec minijail0 -u arc-data-snapshotd -g arc-data-snapshotd \
    /usr/bin/gdbus wait --system --timeout 15 org.chromium.ArcDataSnapshotd

post-stop exec logger -t "${UPSTART_JOB}" "Post-stop arc-data-snapshotd"