#!/bin/sh

###############################################################################
#  name: zfsrestored.sh
#
# Script for restoring the filesystem from backup. Used in conjunection with
#  zfsdumpd.sh (available on BigAdmin)
# Read full description:
#  http://www.sun.com/bigadmin/content/submitted/zfsdumpd_zfsrestored.jsp
###############################################################################


# The backup DIR needs to be same as the one in zfsdump 
DIR=/var/zfsbk

Usage()
{
    cat <<-EOF

	Usage: $1 [-d backup_dir] [-n] [-r] [-z zfs]
		
        -d = where to restore 
        -n = do not back up to a temporary dir before restore
        -r = recursively restore
        -z = file system to restore in format of tank/home. Only one file system is supported at this time.

	EOF
}

GetBackupfileprefixFromZfsname ()
{
    c=0
    for str in `echo $1 | awk -F/ '{ for( i=1 ; i <= NF ; i++ ){print $i}}`
    do
        c=`expr $c + 1`
        if [ $c -eq 1 ]
        then
            file_prefix="$str"
        else
            file_prefix="${file_prefix}_$str"
        fi
    done
    echo $file_prefix
}
    
GetZfsnameFromSnapshot ()
{
    c=0 
    for str in `echo $1 | awk -F/ '{print $NF}' | awk -F. '{print $1}' \
         | awk -F_ '{ for( i=1 ; i <= NF ; i++ ){ print $i}}`
    do
        c=`expr $c + 1`
        if [ $c -eq 1 ]
        then
            zfsname="$str"
        else
            zfsname="${zfsname}/$str"
        fi 
    done
    echo $zfsname
}
 
CheckBackupNeed ()
{
    each_zfs=$1
    pass=0

    if echo $POOLS | grep -w $each_zfs > /dev/null
    then
        :
    else
        file_prefix=`GetBackupfileprefixFromZfsname $each_zfs`

        if find "$DIR" | grep "$file_prefix\." >/dev/null 2>&1
        then
            :
        else 
            echo "Please backup $each_zfs"
            pass=1
        fi
    fi 

    [ $pass -eq 1 ] && exit 2
}

CheckBackupNeeds ()
{
    pass=0
    for each_zfs in $ZFSs
    do
        if echo $POOLS | grep -w $each_zfs > /dev/null
        then
            :
        else
            file_prefix=`GetBackupfileprefixFromZfsname $each_zfs`
    
            if find "$DIR" | grep "$file_prefix\." >/dev/null 2>&1
            then
                :
            else 
                echo "Please backup $each_zfs"
                pass=1
            fi
        fi 
    done

    [ $pass -eq 1 ] && exit 2
}

RestoreSingleCurrentZfs ()
{
    each_zfs=$1 
    if echo $POOLS | grep -w $each_zfs > /dev/null
    then
        echo "Warning: $each_zfs is not allowed to restore. You may use zfs receive $each_zfs/xxx" 
    else
        file_prefix=`GetBackupfileprefixFromZfsname $each_zfs`
        BACKUPSNAPSHOT=`find "$DIR" | grep "$file_prefix\."`  

        if zfs receive $each_zfs < $BACKUPSNAPSHOT; then
            echo "$each_zfs is restored from $BACKUPSNAPSHOT"
        fi 
    fi 
}
 
RestoreSingleBackupZfs ()
{
    file_prefix=`GetBackupfileprefixFromZfsname $1`

    if find "$DIR" | egrep "${file_prefix}\." >/dev/null 2>&1
    then
            snapshot=`find "$DIR" | egrep "${file_prefix}\." | head -n 1`
            zfsname=`GetZfsnameFromSnapshot $snapshot` 

            if zfs receive $zfsname < "$snapshot"; then
                 echo "$zfsname is restored from $snapshot." 
            fi
    else
        echo "Error: Backup file $file_prefix.* does not exist in $DIR"
        exit 2
    fi
}

RestoreBasedonCurrentZfss ()
{
    for myzfs in $ZFSs; do
        RestoreSingleCurrentZfs $myzfs
    done
}
 
RestoreBasedonBackupZfss ()
{
    file_prefix=`GetBackupfileprefixFromZfsname $1`

    if find "$DIR" | egrep "${file_prefix}_|${file_prefix}\." >/dev/null 2>&1
    then
        for snapshot in `find "$DIR" | egrep "${file_prefix}_|${file_prefix}\."`
        do
            zfsname=`GetZfsnameFromSnapshot $snapshot` 

            if zfs receive $zfsname < "$snapshot"; then
                 echo "$zfsname is restored from $snapshot." 
            fi
        done
    else
        echo "Error: Backup file $file_prefix.* does not exist in $DIR"
        exit 2
    fi
}

############################################################################### 
# main()
############################################################################### 

recursive=1
nobackup=1

while getopts 'd:nrz:' opt 2>/dev/null
do
    case "$opt" in
    d) DIR="$OPTARG";;
    n) nobackup=0;;
    r) recursive=0;;
    z) zfs="$OPTARG";;
   \?) Usage $0; exit ;; 
    esac
done

[ $# -ne `expr $OPTIND - 1` ] && Usage $0 && exit 2

[ -d $DIR ] || mkdir -p $DIR
DIRTMP=${DIR}_tmp
[ -d $DIRTMP ] || mkdir -p $DIRTMP

POOLS=`zpool list -o name | grep -vw NAME`

if [ "X$zfs" != X ]
then
    if echo $zfs | egrep "^/|/$" > /dev/null
    then
        echo "The format of zfs is tank/home/norma"
        exit 2
    fi

    if [ $recursive -eq 0 ]
    then
        if ZFSs=`zfs list -t filesystem -o name -r $zfs 2>/dev/null | grep -vw NAME`
        then
            CheckBackupNeeds
            [ $nobackup -eq 1 ] && zfsdumpd.sh -d $DIRTMP -r -z $zfs
            zfs destroy -r $zfs

            if RestoreBasedonCurrentZfss; then
                echo "\nYou may empty $DIRTMP after checking the restoration."
            fi
        else
            RestoreBasedonBackupZfss $zfs
        fi 
    else
        if zfs list -t filesystem -o name $zfs >/dev/null 2>&1
        then
            if echo $POOLS | grep -w $zfs > /dev/null
            then
                echo "Error: $zfs is not allowed to restore directly. Please use 'zfs receive $zfs/xxx'" 
                exit 2
            fi

            CheckBackupNeed $zfs
            [ $nobackup -eq 1 ] && zfsdumpd.sh -d $DIRTMP -z $zfs

  
            pid=$$
            zfs rename $zfs ${zfs}_$pid
            RestoreSingleCurrentZfs $zfs

            zfs_c=`echo $zfs | nawk -F'/' '{print NF}'`
            zfs_c=`expr $zfs_c + 1`

            for zpid in `zfs list -t filesystem -o name -r ${zfs}_$pid | grep  ${zfs}_${pid}/`
            do
                if [ `echo $zpid | nawk -F'/' '{print NF}'` -eq $zfs_c ]; then
                    zfs rename $zpid `echo $zpid | sed "s,^${zfs}_$pid,$zfs,"`
                fi
            done

            zfs destroy -r ${zfs}_$pid
            echo "\nYou may empty $DIRTMP after checking the restoration."
        else
            RestoreSingleBackupZfs $zfs
        fi 

    fi
else
    for zfs in $POOLS
    do
        ZFSs=`zfs list -t filesystem -o name -r $zfs | grep -vw NAME`
        CheckBackupNeeds
    done

    [ $nobackup -eq 1 ] && zfsdumpd.sh -d $DIRTMP

    for zfs in $POOLS
    do
        ZFSs=`zfs list -t filesystem -o name -r $zfs | grep -vw NAME`
        zfs destroy -r $zfs
        RestoreBasedonCurrentZfs 
    done

    echo "\nYou may empty $DIRTMP after checking the restoration."
fi

##############################################################################
### This script is submitted to BigAdmin by a user of the BigAdmin community.
### Sun Microsystems, Inc. is not responsible for the
### contents or the code enclosed. 
###
###
### Copyright 2008 Sun Microsystems, Inc. ALL RIGHTS RESERVED
### Use of this software is authorized pursuant to the
### terms of the license found at
### http://www.sun.com/bigadmin/common/berkeley_license.html
##############################################################################