#!/bin/bash
#
# bpcdump
# Version: __appVersion__
#
# Copyright (C) 2008-2012 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
export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/usr/sbin:$PATH
SCRIPT_EXT="conf start stop mount umount"
CONF_DIR=/etc/vz/conf
INFO=$(mktemp -q /tmp/bpcdump.XXXXX)

# FUNCTIONS

info()
{
    if [ -n "$INFO" ]; then
	echo "$*" | tee -a "$INFO"
    else
	echo "$*"
    fi
}

error()
{
    if [ -n "$INFO" ]; then
	echo "$*" | tee -a "$INFO" >&2
    else
	echo "$*"
    fi
}

restartve()
{
    if [ -n "$mounted" ]; then
	info "remounting VEID $VEID"
	mount $VEMNT && unset mounted
    fi
    if [ -n "$running" ]; then
	info "restarting VEID $VEID"
	vzctl start $VEID && unset running
	if [ $? = 0 ]; then
	    info "VEID $VEID has been started"
	else
	    error "VEID $VEID failed to start; backup continues"
	fi
    fi
}

cleanup()
{
    ret="$1"
    shift
    msg="$*"
    [ -z "$ret" ] && ret=-1
    [ -z "$msg" ] && msg=undef
    restartve
    if [ "$ret" = "0" ]; then
	info "Backup completed on $(date)"
	info "cleanup message: $msg"
	info "exit $ret"
	touch "$EXTVEIDFS/good"
    else
	error "Backup TERMINATED on $(date)"
	error "cleanup message: $msg"
	error "exit $ret"
	touch "$EXTVEIDFS/bad"
    fi
    [ -n "$backupwarn" ] && info "WARNINGS FOUND" >> "$INFO"
    exit $ret
}

# MAIN

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

+EOF+

trap "cleanup 1 \"termination by signal\"" SIGINT SIGTERM

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
    info "$EXTFS is mounted"
fi

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

if [ ! -d "$VEMNT" ]; then
    cleanup 1 "mount point for VEID $VEID does not exist"
else
    info "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
    info "VEID $VEID is mounted on $VEMNT"
fi

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

# Copy the VE's configuration file into its /etc/vzdump directory, as vzdump
# does (for consistency)
for file in $(echo "$SCRIPT_EXT"); do
    if [ -f "$file" ]; then
	destdir="${VEMNT}/etc/vzdump"
	mkdir -p "$destdir"
	info "Preserve config file ${VEID}.${SCRIPT_EXT}"
	cp "${CONF_DIR}/${VEID}.${SCRIPT_EXT}" "${destdir}/vps.${SCRIPT_EXT}"
    fi
done

# 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))
    info "VEID fs contains $srcblks blocks"
    info "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.
# Assume backups for any VE are fair game for removal if space is needed.
# Other disk contents shall not be removed.
dstblks=$(df -P "$EXTFS" | grep "$EXTFS" | awk '{ print $4 }')
while [ $dstblks -le $srcblks ]; do
    info "Only $dstblks free on $EXTFS"
    oldest=$(cd $EXTFS && eval ls -td "ve[0-9]*" 2>/dev/null | tail -1)
    if [ -z "$oldest" ]; then
      cleanup 1 "out of space: need $srcblks KB, have $dstblks KB"
    elif [ -d "$EXTFS/$oldest" ]; then
	info "Removing old backup $oldest from $EXTFS"
	rm -rf "$EXTFS/$oldest"
    else
	cleanup 1 "Structure error on $EXTFS.  Correct manually."
    fi
    dstblks=$(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
info "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" || cleanup 1 "cannot mkdir $EXTVEIDFS/"
cd "$EXTVEIDFS" || cleanup 1 "cannot cd into $EXTVEIDFS/"
echo "$STARTDATE" > "$EXTVEIDFS/begin"

# Move temporary INFO file to its permanent home within $EXTVEIDFS
mv "$INFO" "$EXTVEIDFS/info" || cleanup 1 "cannot mv file to $EXTVEIDFS/"
INFO="$EXTVEIDFS/info"

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

# 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" > "$EXTVEIDFS/image.md5sum"
info "$srcmd5 source md5sum"
info "$dstmd5 dest md5sum"
if [ "$srcmd5" != "$dstmd5" -o -z "$srcmd5" ]; then
    backupwarn=1
    error "WARNING: md5 signatures do not match"
else
    info "md5 signatures match"
fi
if [ -n "$WRITEPAR" ]; then
    (cd "$EXTVEIDFS" && time par2 c img)
    ret=$?
    if [ "$ret" != "0" ]; then
	backupwarn=1
	info "WARNING: redundancy failed: par2 returned $ret"
    fi
    (cd "$EXTVEIDFS" && time par2 v img)
    ret=$?
    if [ "$ret" != "0" ]; then
	backupwarn=1
	info "WARNING: redundancy inexact: par2 returned $ret"
    fi
fi

cleanup 0 "successful"

# vi: set shiftwidth=4: