#!/bin/bash
#
# bpcdump
# Copyright (C) 2008 by Titanium Mirror, Inc.
# Author: R. Steve McKown <smckown@titaniummirror.com>
#
# Dumps the BPC VEID to external storage.  It must have its storage on a
# private filesystem mounted at /var/lib/vz/private/$VEID.
#
# A generalized version of this script should be created later.  A recovery
# option within this script should also be created.

# CONSTANTS

VEID=1158
VEDEV=/dev/vg0/ve$VEID
VEMNT=/var/lib/vz/private/$VEID
EXTFS=/media/esata
unset WRITEPAR

# FUNCTIONS

restartve()
{
    if [ -n "$mounted" ]; then
	echo "remounting VEID $VEID" | tee -a "$INFO"
	mount $VEMNT && unset mounted
    fi
    if [ -n "$running" ]; then
	echo "restarting VEID $VEID" | tee -a "$INFO"
	vzctl start $VEID && unset running
    fi
}

cleanup()
{
    ret="$1"
    shift
    msg="$*"
    if [ -z "$INFO" ]; then
	echo "$0: $msg" >&2
    else
	[ -z "$ret" ] && ret=-1
	[ -z "$msg" ] && msg=undef
	restartve
	if [ "$ret" = "0" ]; then
	    echo "$(date)" | tee -a "$INFO"
	    echo "cleanup message: $msg" | tee -a "$INFO"
	    echo "exit $ret" | tee -a "$INFO"
	    touch "$EXTVEIDFS/good"
	else
	    echo "$(date)" | tee -a "$INFO" >&2
	    echo "cleanup message: $msg" | tee -a "$INFO" >&2
	    echo "exit $ret" | tee -a "$INFO" >&2
	    touch "$EXTVEIDFS/bad"
	fi
	[ -n "$backupwarn" ] && echo "WARNINGS FOUND" >> "$INFO"
    fi
    exit $ret
}

# MAIN

if [ $(whoami) != "root" ]; then
    cleanup 1 "script requires super-user privileges"
fi

set $(vzctl status $VEID)
unset exist mounted running backupwarn
[ "$3" = "exist" ] && exist=1
[ "$4" = "mounted" ] && mounted=1
[ "$5" = "running" ] && running=1

if ! mount | grep -q "on $EXTFS"; then
    cleanup 1 "$EXTFS is not mounted"
else
    echo "$EXTFS is mounted"
fi

if [ -z "$exist" ]; then
    cleanup 1 "VEID $VEID does not exist"
else
    echo "VEID $VEID exists"
fi

if [ ! -d "$VEMNT" ]; then
    cleanup 1 "mount point for VEID $VEID does not exist"
else
    echo "VEID $VEID has private mount point"
fi

if ! grep -q "$VEMNT[ 	]" /etc/fstab; then
    cleanup 1 "mount point for VEID $VEID not in /etc/fstab"
fi

if ! mount | grep -q "on $VEMNT"; then
    cleanup 1 "$VEMNT is not mounted"
else
    echo "VEID $VEID is mounted on $VEMNT"
fi

if [ -n "$running" ]; then
    echo "stopping VEID $VEID"
    vzctl stop $VEID
fi

# Unmount the filesystem, first getting its size
if mount | grep -q "on $VEMNT"; then
    mounted=1 # duplicate; vzctl status told us...
    srcblks=$(df -P "$VEMNT" | grep "$VEMNT" | awk '{ print $2 }')
    # Add 5% buffer
    t=$((srcblks / 20))
    srcblks=$((srcblks + t))
    echo "VEID fs contains $srcblks blocks"
    echo "unmount VEID $VEID"
    umount "$VEMNT"
else
    cleanup 1 "VEID private fs must be mounted to determine its size"
fi

# Before we begin writing, remove old backup dirs until we have room
dstblks=$(df -P "$EXTFS" | grep "$EXTFS" | awk '{ print $4 }')
while [ $dstblks -le $srcblks ]; do
    oldest=$(cd $EXTFS && ls -ltd "ve${VEID}*" 2>/dev/null | tail -1 | \
	awk '{ print $8 }')
    if [ -d "$oldest" ]; then
	echo "Removing old backup $oldest from $EXTFS"
	rm -rf $oldest
    fi
    dstblks=$(df -P "$EXTFS" | grep "$EXTFS" | awk '{ print $4 }')
done
if [ $dstblks -le $srcblks ]; then
    cleanup 1 "out of space: need $srcblks KB, have $dstblks KB"
fi
echo "Archive space ok: need $srcblks KB, have $dstblks KB"

EXTVEIDFS="$EXTFS/ve$VEID-$(date +'%Y%m%d')"
if [ -d "$EXTVEIDFS" ]; then
    rm -rf "${EXTVEIDFS}.old"
    mv "$EXTVEIDFS" "${EXTVEIDFS}.old"
else
    rm -rf "$EXTVEIDFS"
fi
mkdir "$EXTVEIDFS"
date > "$EXTVEIDFS/begin"
if ! cd "$EXTVEIDFS"; then
    cleanup 1 "cannot change into $EXTVEIDFS directory"
fi

INFO="$EXTVEIDFS/info"
cat > "$INFO" <<+EOF+
Date: $(date)
VEID: $VEID
Volume: $VEDEV
dd_rescue log: ddrlog
dd_rescue bad blocks: ddrbb
image file: image

+EOF+
echo "copy $VEID device $VEDEV to $EXTVEIDFS/image" | tee -a "$INFO"
time dd_rescue -Aqy 8192 -l "$EXTVEIDFS/ddrlog" -o "$EXTVEIDFS/ddrbb" \
	$VEDEV "$EXTVEIDFS/image"
ret=$?
if [ "$ret" != "0" ]; then
    backupwarn=1
    echo "WARNING: dd_rescue returned $ret" | tee -a "$INFO" >&2
fi
echo "calculate md5sum for $VEDEV (src)" | tee -a "$INFO"
srcmd5=$(md5sum "$VEDEV" 2>&1 | awk '{ print $1 }')
echo "calculate md5sum for image (dst)" | tee -a "$INFO"

# We're done with the partition.  We can restart the VE now.
restartve

# Continue on with archive and validation
(cd "$EXTVEIDFS" && md5sum image >image.md5sum 2>&1 | awk '{ print $1 }')
dstmd5=$(md5sum "$EXTVEIDFS/image" 2>&1 | awk '{ print $1 }')
echo "$dstmd5 image.md5sum" > "$EXTVEIDFS/image.md5sum"
echo "$srcmd5 source md5sum" | tee -a "$INFO"
echo "$dstmd5 dest md5sum" | tee -a "$INFO"
if [ "$srcmd5" != "$dstmd5" -o -z "$srcmd5" ]; then
    backupwarn=1
    echo "WARNING: md5 signatures do not match" | tee -a "$INFO" >&2
else
    echo "md5 signatures match" | tee -a "$INFO"
fi
if [ -n "$WRITEPAR" ]; then
    (cd "$EXTVEIDFS" && time par2 c img)
    ret=$?
    if [ "$ret" != "0" ]; then
	backupwarn=1
	echo "WARNING: redundancy failed: par2 returned $ret" | tee -a "$INFO"
    fi
    (cd "$EXTVEIDFS" && time par2 v img)
    ret=$?
    if [ "$ret" != "0" ]; then
	backupwarn=1
	echo "WARNING: redundancy inexact: par2 returned $ret" | tee -a "$INFO"
    fi
fi

cleanup 0 "successful"