# 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    "Start the seneschal service"
author         "chromium-os-dev@chromium.org"

# The file server uses O_PATH fds and so needs a higher limit than usual for the
# number of open files.
limit nofile 1024 262144

# Start the seneschal service, which acts as the steward of the user's /home.
start on starting vm_concierge
stop on stopped vm_concierge
respawn
expect daemon

pre-start script
  # If the pre-start script fails, by default nothing gets written to
  # the logs. Make sure we can find out what went wrong by
  # re-directing stderr to a temp file and sending it to the syslog if
  # we encounter an error.
  tmp_log="$(mktemp)"
  exec 2>"${tmp_log}"
  dump_log() {
    if [ $? != 0 ]; then
      set +x
      # Split up lines before calling logger to avoid running into line limits.
      xargs -n 1 -d"\n" logger --tag "${UPSTART_JOB}" < "${tmp_log}"
    fi
  }
  trap dump_log EXIT
  set -x

  # Make sure the necessary kernel modules are loaded.
  modprobe -q vhost-vsock

  # Ensure arc mount point exists, even if arc is not running.
  mkdir -p /run/arc/sdcard

end script

# Since we are in an unprivileged user namespace, all bind mounts require the
# MS_REC flag to also be set and bind mounting / recursively defeats the purpose
# of using pivot_root.  Instead we use nested jails: one to set up the mounts
# and another to create the user namespace.  /proc needs to be mounted read-
# write so that we can set the uid and gid maps.
#
# Normally -U would imply remounting /proc as ro, but when running as
# init we need to do it explicitly. Remounting /proc also causes it to
# only show processes in the PID namespace.
#
# -Kslave is applied to propagate /media (drivefs and removable media), and
# /run/arc/sdcard (android) mounts into seneschal's mount namespace.
#
# Map uid/gid android-root (655360) and gid android-everybody (665357).
exec minijail0 -vdi --uts \
     -Kslave \
     -P /mnt/empty \
     -b /,/ \
     -b /dev/log,/dev/log,1 \
     -k 'proc,/proc,proc,MS_NOSUID|MS_NODEV|MS_NOEXEC' \
     -k 'run,/run,tmpfs,MS_NOSUID|MS_NODEV|MS_NOEXEC,mode=755,size=64M' \
     -b /run/dbus,/run/dbus,1 \
     -b /run/seneschal,/run/seneschal,1 \
     -k '/home,/home,none,MS_BIND|MS_REC' \
     -k '/media,/media,none,MS_BIND|MS_REC' \
     -k '/run/arc/sdcard,/run/arc/sdcard,none,MS_BIND|MS_REC' \
     -- /sbin/minijail0 -nlNpve --uts -U -I -i -Kslave \
        -k 'proc,/proc,proc,MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC' \
        -m"0 20114 1,20115 20115 1,1000 1000 1,655360 655360 1" \
        -M"0 20114 1,20115 20115 1,1000 1000 2,655360 655360 1,665357 665357 1" \
        -- /usr/bin/seneschal