# Copyright 2016 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 Chromium OS biometrics daemon"
author        "chromium-os-dev@chromium.org"

start on started system-services and stopped bio_crypto_init and started uinput
stop on stopping system-services
respawn
respawn limit 3 10  # if the job respawns 3 times in 10 seconds, stop trying.

env LOG_DIR=/var/log/biod
env FP_DEV=/dev/cros_fp

pre-start script
  mkdir -m 755 -p "${LOG_DIR}"
  chown biod:biod "${LOG_DIR}"
end script

script
  # Check the existence of ${FP_DEV}.
  if [ ! -c "${FP_DEV}" ]; then
    echo "${FP_DEV} not available, exiting." > /var/log/biod.out
    exit 0
  fi

  # Here (in order) are a list of the args added:
  # - Create and enter new UTS namespace (hostname/NIS domain name).
  # - Create and enter new network namespace.
  # - Create and enter new IPC namespace.
  # - Create and enter new cgroup namespace.
  # - Create and enter new PID namespace.
  # - Set mount namespace to be a slave mount.
  # - Set up a new VFS namespace (although this should be covered by
  #   minimalistic-mountns, leaving this out yields the following error:
  #   "Can't skip marking mounts as MS_PRIVATE without mount namespaces.")
  # - Use the minimal mountns profile to start.
  # - Get a writeable and empty /run tmpfs path.
  # - Mount dbus.
  # - Mount daemon store with the MS_BIND|MS_REC options to handle the case
  #   biod starts after the user's cryptohome is already mounted (e.g. after a
  #   crash).
  # - Get a writeable and empty /var tmpfs path.
  # - Mount the log directory in it.
  # - Mount the metrics directory.
  # - Mount the FPMCU dev node.
  # - Run as biod user and group.
  # - Inherit supplementary groups from from user biod.
  # - Grant no caps.
  # - No new privileges (no_new_privs).
  # - Use biod seccomp policy.
  # - Execute the daemon.
  # - Add the log dir.
  # - Pipe output to biod.out.
  exec minijail0                                                               \
    --uts                                                                      \
    -e                                                                         \
    -l                                                                         \
    -N                                                                         \
    -p                                                                         \
    -Kslave                                                                    \
    -v                                                                         \
    --profile minimalistic-mountns                                             \
    -k 'tmpfs,/run,tmpfs,MS_NODEV|MS_NOEXEC|MS_NOSUID,mode=755,size=10M'       \
    -b /run/dbus                                                               \
    -k '/run/daemon-store/biod,/run/daemon-store/biod,none,MS_BIND|MS_REC'     \
    -k 'tmpfs,/var,tmpfs,MS_NODEV|MS_NOEXEC|MS_NOSUID,mode=755,size=10M'       \
    -b ${LOG_DIR},,1                                                           \
    -b /var/lib/metrics,,1                                                     \
    -b ${FP_DEV}                                                               \
    -b /dev/uinput                                                             \
    -u biod -g biod                                                            \
    -G                                                                         \
    -c 0                                                                       \
    -n                                                                         \
    -S /usr/share/policy/biod-seccomp.policy                                   \
    -- /usr/bin/biod                                                           \
    --log_dir=${LOG_DIR}                                                       \
    >/var/log/biod.out 2>&1
end script