blockrestore

#!/bin/bash
#
#    blockrestore - Restore archive created by blockbackup
#
#
#    Copyright (C) 2016-2018 Marek Wodzinski
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#


USE_ZIP=0
SOURCE=
DEST=
CHUNK=
#DO_MD5=0
ZCAT="cat"
ZEXT=
FAST=0


function usage() {
    echo "ERROR: unknown option/paramter"
    echo "Usage: blockrestore -s directory -d device [-c chunk] [-f]"
    echo "	-s|--source	source directory"
    echo "	-d|--dest	destination device"
    echo "	-c|--chunk	chunk size (default=autodetect)"
    #echo "	-m|--md5	check md5 for every chunk"
    echo "	-f|--fast	run in fast mode (could not work in some circumstances!)"
    exit 1
}


#get/parse parameters
while true; do
    case "$1" in
	-s|--source)
	    shift
	    SOURCE="$1"
	    if [ ! -d "$SOURCE" ]; then
		echo "ERROR: source must be a directory!"
		exit 1
	    fi
	    ;;
	-d|--dest)
	    shift
	    DEST="$1"
	    if [ ! -b "$DEST" ]; then
		echo "ERROR: destination must a device"
		exit 1
	    fi
	    ;;
	-c|--chunk)
	    shift
	    CHUNK=$1
	    ;;
	#-m|--md5)
	#    DO_MD5=1
	#    ;;
	-f|--fast)
	    FAST=1
	    ;;
	*)
	    usage
	    ;;
    esac
    shift
    if [ -z "$1" ]; then break; fi
done

if [ -z "$SOURCE" -o -z "$DEST" ]; then usage; fi

#### Some guessing

# get first file in directory
FIRSTFILE=$(find "$SOURCE" -type f -regextype posix-extended -regex ".*/[0-9]+/[0-9]+(\.zst)?" -print -quit)
if [ -z "$FIRSTFILE" ]; then
    echo "ERROR: Couldn't find files matching archive"
    exit 1
fi

echo "First file used to autodetect: $FIRSTFILE"

# is gzipped?
echo "$FIRSTFILE"|grep -q "\.zst$"
if [ $? -eq 0 ]; then
    USE_ZIP=1
    ZEXT=.zst
    ZCAT="zstdcat"
    echo "Found zstd archive"
else
    echo "It seems that archive is not zstd"
fi

# chunk handling
if [ -z "$CHUNK" ]; then
    # autodetect chunk size
    CHUNK=$($ZCAT "$FIRSTFILE"|wc -c)
    echo "Autodetected chunk size: $CHUNK"
else
    echo "Using command line chunk size $CHUNK"
fi


echo "Making restore of $SOURCE to device $DEST.
Are you sure? (type YES if so)"
read yesno
if [ "$yesno" != "YES" ]; then
    echo "Aborting"
    exit 1
fi

echo "Restoring...."

if [ $FAST -eq 0 ]; then
    # slow but safe restore
    find "$SOURCE" -type f -regextype posix-extended -regex ".*/[0-9]+/[0-9]+$ZEXT" -print | while read -r part; do
	echo "$part"
	if [ $USE_ZIP -eq 1 ]; then
	    part=$(echo "$part"|sed "s/$ZEXT$//")
	fi
	CHUNKNR=$((10#$(basename "$part")))
	echo $CHUNKNR
	$ZCAT "$part$ZEXT"|dd of="$DEST" obs=$CHUNK seek=$CHUNKNR
    done
else
    # fast restore
    echo " wait a while to find all files in archive, next you can use 'killall -USR1 dd' to check progess"
    find "$SOURCE" -type f -regextype posix-extended -regex ".*/[0-9]+/[0-9]+$ZEXT" -print|sort|xargs -n100 -r $ZCAT|dd status=progress of="$DEST" obs=$CHUNK
fi

echo " end!"