#!/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

# Flush buffers to disk to reflect this part of shutdown in the metrics.
sync

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

# To be safe, flush buffers to disk again before unmounting. (From
# https://crbug.com/760007 it seems that a failed umount can get the filesystem
# into a state that renders a subsequent sync ineffective.)
sync

# Log all the unmount logic to a temp file and move it over to stateful if any
# of the steps failed.
(
set -x

# Unmount /var/run and /var/lock, which were bind mounted to /run and /run/lock
# respectively to enable backwards compatibility for accessing /run (tmpfs for
# runtime data) through /var.
umount -n /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.
  rc=0
  for i in 1 2 3 4 5 6 7 8 9 10; do
    mount-encrypted umount
    rc=$?
    if [ $rc -eq 0 ]; then
      break
    fi
    sleep 0.1
  done
  umount -n /usr/local /home /mnt/stateful_partition
  # Merge the exit status with the earlier mount-encrypted call.
  exit $(( rc | $? ))
else
  umount -n /var /usr/local /home /mnt/stateful_partition
  exit $?
fi
) >/tmp/umount-encrypted.log 2>&1

if [ $? -ne 0 ] ; then
  mv /tmp/umount-encrypted.log /mnt/stateful_partition/
  (
    set -x
    mount
    dmsetup info
    lsof -n
  ) > /mnt/stateful_partition/shutdown_stateful_umount_failure 2>&1
else
  rm -f /tmp/umount-encrypted.log
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