#!/bin/sh
# Copyright (c) 2013 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.

# Shutdown is best-effort. We don't want to die on errors.
set +e

bootstat shutdown-start

. /sbin/killers

# Remount root in case a developer has remounted it rw for some reason.
mount -n -o remount,ro /

# TODO: swapoff as necessary.

# Kill any that may prevent us from unmounting the stateful partition
# or the crypto-home and then unmount. These should be all that we need
# to unmount for a clean shutdown.
kill_with_open_files_on /mnt/stateful_partition /home/chronos /var

# Signal that the clean shutdown point was reached (or at least as
# close to that point as we can be before stateful is unmounted).
crash_reporter --clean_shutdown

# CROS_DEBUG equals one if we've booted in developer mode or we've booted a
# developer image.
crossystem "cros_debug?1"
CROS_DEBUG=$((! $?))

STATEFUL_UPDATE="/mnt/stateful_partition/.update_available"

if [ "$CROS_DEBUG" = "1" -a -f "$STATEFUL_UPDATE" ] ; then
  STATEFUL_UPDATE_ARGS=$(cat "$STATEFUL_UPDATE")

  if [ "$STATEFUL_UPDATE_ARGS" = "clobber" ] ; then
    PRESERVE_DIR="/mnt/stateful_partition/unencrypted/preserve"

    # Measure shutdown time up to this point.
    bootstat before_preserve

    # We preserve a few files. Make sure preservation directory starts empty.
    rm -rf "${PRESERVE_DIR}/log"
    mkdir -p -m 0755 "${PRESERVE_DIR}"
    cp -a "${MNTS}/var/log" "${PRESERVE_DIR}"

    # We are about to put this into a directory that will shortly be wiped
    # out. Keep a timestamp where it will be preserved as well.
    PRESERVE_METRICS="${PRESERVE_DIR}/log/metrics"
    bootstat_archive "${PRESERVE_METRICS}/shutdown.$(date '+%Y%m%d%H%M%S')"
  fi
fi

# Measure shutdown time up to this point.
bootstat_archive /var/log/metrics/shutdown.$(date '+%Y%m%d%H%M%S')

# Lazy umount the tmpfs dirs under /var so we can immediately umount it.
umount -n -l /var/run /var/lock

# Remove symbolic links so that in case of auto-update rollback, the pre-38
# chromeos_startup does not choke on them (which has been widely observed in the
# wild, cf. https://crbug.com/447227).
# TODO(tnagel): Remove once the amount of pre-38 installations has become
# negligible.
rm -f /var/run /var/lock

if [ -e /dev/mapper/encstateful ]; then
  # Give mount-encrypted umount 10 times to retry, otherwise
  # it will fail with 'device is busy' because lazy umount does not finish
  # clearing all reference points yet. Check crosbug.com/p/21345.
  for i in 1 2 3 4 5 6 7 8 9 10; do
    mount-encrypted umount > /tmp/umount-encrypted.log 2>&1
    rc=$?
    if [ $rc -eq 0 ]; then
      break
    fi
    sleep 0.1
  done
  if [ $rc -ne 0 ] ; then
    mv /tmp/umount-encrypted.log /mnt/stateful_partition/
  fi
  umount -n /usr/local /home /mnt/stateful_partition
  rc=$?
else
  umount -n /var /usr/local /home /mnt/stateful_partition
  rc=$?
fi
if [ $rc -ne 0 ] ; then
  mount > /mnt/stateful_partition/shutdown_stateful_umount_failure
fi

# Just in case something didn't unmount properly above.
sync

# Display low battery icon if shutting down due to low battery.
# SHUTDOWN_REASON is passed in with the runlevel event from power manager.
if [ "$SHUTDOWN_REASON" = "low-battery" ]; then
  display_low_battery_alert
fi

# Ensure that we always claim success.
exit 0