#!/bin/sh
#
# e2check

# Released under the GNU General Public License, either version 2 or
#  (at your option) any later version.

# Overview:
#
#  Run this from cron each night.  If the machine is on AC power, it
#  will run the checks; otherwise they will all be skipped.  (If the
#  script can't tell whether the machine is on AC power, a setting in
#  the configuration file (/etc/e2check.conf) decides whether it will
#  continue or abort.)
#
#  The script will then decide which filesystems in /etc/fstab are on
#  logical volumes, and can therefore be checked via an LVM snapshot.
#  Each of these filesystems will be queried to find its last check
#  day, and if that was more than $INTERVAL days ago (where INTERVAL
#  is set in the configuration file as well), then the script will
#  take an LVM snapshot of the filesystem and run e2fsck on the
#  snapshot.  The snapshot's size can be set via either the SNAPSIZE
#  option in the options field in /etc/fstab, or the DEFAULT_SNAPSIZE
#  option in /etc/e2check.conf -- but make sure it's set large enough.
#  After e2fsck finishes, the snapshot is destroyed.
#
#  Any filesystem that passes e2fsck will have its last-check time
#  updated (in the real superblock, not the snapshot); any filesystem
#  that fails will send an email notification to a configurable user
#  ($EMAIL).  This $EMAIL setting is optional, but its use is highly
#  recommended, since if any filesystem fails, it will need to be
#  checked manually offline.

function on_ac_power() {
	local any_known=no

	# try sysfs power class first
	if [ -d /sys/class/power_supply ] ; then
		for psu in /sys/class/power_supply/* ; do
			if [ -r "${psu}/type" ] ; then
				type="`cat "${psu}/type"`"

				# ignore batteries
				[ "${type}" = "Battery" ] && continue

				online="`cat "${psu}/online"`"

				[ "${online}" = 1 ] && return 0
				[ "${online}" = 0 ] && any_known=yes
			fi
		done

		[ "${any_known}" = "yes" ] && return 1
	fi

	# else fall back to AC adapters in /proc
	if [ -d /proc/acpi/ac_adapter ] ; then
		for ac in /proc/acpi/ac_adapter/* ; do
			if [ -r "${ac}/state" ] ; then
				grep -q on-line "${ac}/state" && return 0
				grep -q off-line "${ac}/state" && any_known=yes
			elif [ -r "${ac}/status" ] ; then
				grep -q on-line "${ac}/status" && return 0
				grep -q off-line "${ac}/status" && any_known=yes
			fi
		done

		[ "${any_known}" = "yes" ] && return 1
	fi

	if [ "$AC_UNKNOWN" == "CONTINUE" ] ; then
		return 0   # assume on AC power
	elif [ "$AC_UNKNOWN" == "ABORT" ] ; then
		return 1   # assume on battery
	else
		echo "Invalid value for AC_UNKNOWN in the config file" >&2
		exit 1
	fi
}

function check_fs() {
	local vg="$1"
	local lv="$2"
	local opts="$3"
	local snapsize="${DEFAULT_SNAPSIZE}"

	case "$opts" in
		*SNAPSIZE=*)
		# parse out just the SNAPSIZE option's value
		snapsize="${opts##*SNAPSIZE=}"
		snapsize="${snapsize%%,*}"
		;;
	esac   # else leave it at DEFAULT_SNAPSIZE

	[ -z "$snapsize" ] && return 1

	local tmpfile=`mktemp -t e2fsck.log.XXXXXXXXXX`
	trap "rm $tmpfile ; trap - RETURN" RETURN

	local start="$(date +'%Y%m%d%H%M%S')"

	lvcreate -s -L "${snapsize}" -n "${lv}-snap" "${vg}/${lv}"

	if nice logsave -as $tmpfile e2fsck -p -C 0 "/dev/${vg}/${lv}-snap" && \
			nice logsave -as $tmpfile e2fsck -fy -C 0 "/dev/${vg}/${lv}-snap" ; then
		echo 'Background scrubbing succeeded!'
		tune2fs -C 0 -T "${start}" "/dev/${vg}/${lv}"
	else
		echo 'Background scrubbing failed! Reboot to fsck soon!'
		tune2fs -C 16000 -T "19000101" "/dev/${vg}/${lv}"

		if test -n "$EMAIL"; then
			mail -s "E2fsck of /dev/${vg}/${lv} failed!" $EMAIL < $tmpfile
		fi
	fi

	lvremove -f "${vg}/${lv}-snap"
}

set -e

# pull in configuration -- don't bother with a parser, just use the shell's
. /etc/e2check.conf

# check whether the machine is on AC power: if not, skip the e2fsck
on_ac_power || exit 0

# parse up fstab
grep -v '^#' /etc/fstab | grep -v '^$' | awk '$6!=0 {print $1,$3,$4;}' | \
while read FS FSTYPE OPTIONS ; do
	# Use of tune2fs in check_fs, and dumpe2fs below, means we can
	#  only handle ext2/ext3 FSes
	[ "$FSTYPE" != "ext3" || "$FSTYPE" != "ext2" ] && continue

	# get the volume group (or an error message)
	VG="`lvs --noheadings -o vg_name "$FS" 2>&1`"

	# skip non-LVM devices (hopefully LVM VGs don't have spaces)
	[ "`echo "$VG" | awk '{print NF;}'`" -ne 1 ] && continue

	# get the logical volume name
	LV="`lvs --noheadings -o lv_name "$FS"`"

	# get the last check time plus $INTERVAL days
	check_date=`dumpe2fs -h "/dev/${VG}/${LV}" 2>/dev/null | grep 'Last checked:' | \
		sed -e 's/Last checked:[[:space:]]*//'`
	check_day=`date --date="${check_date} $INTERVAL days" +"%Y%m%d"`

	# get today's date, and skip LVs that don't need to be checked yet
	today=`date +"%Y%m%d"`
	[ "$check_day" -gt "$today" ] && continue

	# else, check it
	check_fs "$VG" "$LV" "$OPTIONS"
done