init/upstart/halt/s3halt.conf

# Copyright 2015 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     "Go into S3 (suspend) for halt, then reboot when waking up"
author          "chromium-os-dev@chromium.org"

env BTMGMT_JAIL='/sbin/minijail0 -u bluetooth -g bluetooth -G -c 3500 -- /usr/bin/btmgmt'
env BT_ADDR_RE='^\s*addr (([0-9A-F]){2}:){5}([0-9A-F]){2}\s'

start on runlevel 0
stop on runlevel [!0]

# SHUTDOWN_REASON is passed to initctl by powerd_setuid_helper.
# Export it here so that the pre-shutdown job can log it.
export SHUTDOWN_REASON

exec chromeos_shutdown

pre-start script
  # We need to record if Bluetooth was on so we can turn it back on in
  # post-stop.  Note that there are quite a few ugly bits here:
  #
  # 1. The stopping of bluetoothd is kicked off _before_ we run but
  #    possibly might not have completed yet.  That means it might or
  #    might not have powered off Bluetooth devices already.  We get
  #    around this by parsing the settings directly.
  # 2. We have to run some code in pre-start (here) because
  #    "/var/lib/bluetooth" isn't available in post-stop.  Then we
  #    somehow need to communicate to post-stop.  If we had upstart 1.7+
  #    we could use initctl set-env but we don't.  The best we can do is
  #    use /tmp and try to do it in a safe way (since /tmp is world
  #    writable and we run as root we need to be careful of symlinks).
  #    Using mktemp should be safe and we'll check for the existence of
  #    the file (owned by us) in post-stop.
  # 3. It's pretty ugly to let Bluetooth turn off (when bluetoothd
  #    stops) and then turn it back on.  Luckily wakeup still appears to
  #    work in this case (at least on Mickey), but it's still ugly.  It
  #    may be that things still work because nowhere in the kernel do we
  #    ever turn the Bluetooth regulator off.  A cleaner solution would
  #    be to use btmgmt to tell bluetoothd not to power off upon exit
  #    so that we could do wakeup.  In order to make this work, we'd not
  #    only need to add this feature to bluetoothd, but we'd also need
  #    to find a way to run at halt time before bluetoothd exited and
  #    also (ideally) still find a way to turn Bluetooth power off
  #    between waking up and rebooting.

  BT_ADDR=$(${BTMGMT_JAIL} info | grep -E "${BT_ADDR_RE}" | head -1 |
            awk '{print $2}')
  if grep -q Powered=true "/var/lib/bluetooth/${BT_ADDR}/settings"; then
    mktemp --tmpdir s3halt.bt.XXXXXXXXX
  fi
end script

post-stop script
  if [ -O /tmp/s3halt.bt.* ]; then
    ${BTMGMT_JAIL} power on

    # A small sleep appears to be needed after powering on...
    sleep 1
  fi

  echo mem > /sys/power/state

  if [ -O /tmp/s3halt.bt.* ]; then
    ${BTMGMT_JAIL} power off
  fi

  reboot --force
end script