2backup.sh

#!/usr/bin/env bash

# 2backup (btrfs backup), a simple snapshots management and backup tool for btrfs.
# Copyright (C) 2023  Babilinx
#
# 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 <https://www.gnu.org/licenses/>.



usage() {
cat << EOF
2backup  Copyright (C) 2023  Babilinx
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; see 'https://www.gnu.org/licenses/gpl-3.0.en.html' for details.

Usage:
  2backup [options] [arguments]
  bb [options] [arguments]

Options:
  profile                                      Interact with profiles.
    arguments:
      create <profile>                         Create a profile.
      delete <profile>                         Delete a profile.
      list                                     List all profiles.
      show <profile>                           Show infos of a profile.

  snapshot                                     Interact with snapshots.
    arguments:
      create <profile>                         Create a snapshot of a profile, with the description given after.
      create <profile> -m <description>        Create a snapshot of a profile with the giver description.
      delete <snapshot ID> -p <profile>        Delete a profile's snapshot (can contain more than one snapshot).
      delete <snapshot hash>                   Delete a given snapshot.
      list                                     List all snapshots.
      list -p <profile>                        List all snapshots of a profile.
      show <snapshot hash>                     Show infos on a snapshot.
      show <snapshot ID> -p <profile>          Show infos on a snapshot of a profile.
      mount <snapshot ID> -p <profile>         Mount a snapshot of a profile.
      mount <snapshot hash>                    Mount a given snapshot.
      umount <snapshot ID> -p <profile>        Unmount a snapshot of a profile.
      umount <snapshot hash>                   Unmount a given snapshot.

  rollback                                     Do rollback stuff.
    arguments:
      <snapshot hash>                          Rollback the given snapshot.
      <snapshot ID> -p <profile>               Rollback a profile to the given snapshot.

EOF
}


init() {
    [ ! -d "/etc/2backup" ] && mkdir /etc/2backup
    [ ! -d "/etc/2backup/profiles" ] && mkdir /etc/2backup/profiles
}


profile_create() {
    if [[ ! "$1" == "" ]]; then
        PROFILE="$1"
        cat > /etc/2backup/profiles/$PROFILE << "EOF"
SUBV=("@default1" "@default2")
SUBV_MNTPT=("/default1" "/default1/default2")

TIMELINE_LIMIT_HOURLY="0"
TIMELINE_LIMIT_DAILY="0"
TIMELINE_LIMIT_WEEKLY="0"
TIMELINE_LIMIT_MONTHLY="0"
TIMELINE_LIMIT_YEARLY="0"
EOF
        echo "Profile '$PROFILE' created. Configure it at '/etc/2backup/profiles/$PROFILE'."
        exit

    else
        >&2 echo "Profile name can't be blank!"
        exit 1
    fi
}


profile_delete() {
    PROFILE="$1"

    if [ -e "/etc/2backup/profiles/$PROFILE" ]; then
        read -p "Do you really want to delete profile '$PROFILE'? [y/N] " ASK

        if [[ "$ASK" == "y" || "$ASK" == "Y" ]]; then
            rm /etc/2backup/profiles/$PROFILE
            echo "Profile '$PROFILE' as been deleted."
            exit
        else
            echo "Deletion aborted."
            exit
        fi
    else
        >&2 echo "Profile '$PROFILE' do not exist!"
        exit 1
    fi
}


profile_show() {
    PROFILE="$1"

    if [ ! -e "/etc/2backup/profiles/$PROFILE" ]; then
        >&2 echo "Profile '$PROFILE' do not exist!"
        exit 1
    fi

    source /etc/2backup/profiles/$PROFILE

    echo "Affected subvolume(s): ${SUBV[@]}"
    echo "Subvolume(s) mountpoint: {SUBV_MNTPT[@]}"
    echo "Max hourly snapshots: $TIMELINE_LIMIT_HOURLY"
    echo "Max daily snapshots: $TIMELINE_LIMIT_DAILY"
    echo "Max weekly snapshots: $TIMELINE_LIMIT_WEEKLY"
    echo "Max mounthly snapshots: $TIMELINE_LIMIT_MONTHLY"
    echo "Max yearly snapshots: $TIMELINE_LIMIT_YEARLY"
    exit
}


profile_list() {
    echo "List of profiles:"
    ls /etc/2backup/profiles
    exit
}


snapshot_create() {
    PROFILE="$1"

    if [ ! -e "/etc/2backup/profiles/$PROFILE" ]; then
        >&2 echo "Profile '$PROFILE' do not exist!"
        exit 1
    fi

    source /etc/2backup/profiles/$PROFILE

    if [[ ! "${#SUBV[@]}" == "${#SUBV_MNTPT[@]}" ]]; then
        >&2 echo "There are error(s) in '$PROFILE' configuration file!"
        >&2 echo "The number of subvolumes affected to it is different than the number of mountpoints!"
        >&2 echo "${#SUBV[@]} and ${#SUBV_MNTPT[@]}"
        exit 1
    fi

    if [[ "$GREATEST_SUBV_ID" == "" ]]; then
        NUMBER=1
        echo "GREATEST_SUBV_ID=1" >> /etc/2backup/profiles/$PROFILE
    else
        NUMBER=$(($GREATEST_SUBV_ID+1))
        sed -i "s/GREATEST_SUBV_ID=.*/GREATEST_SUBV_ID=${NUMBER}/g" /etc/2backup/profiles/$PROFILE
    fi

    if [[ ! "$2" == "" ]]; then
        DESCRIPTION="$2"
    else
        if [[ $EDITOR == "" ]]; then
            nano "/tmp/2backup_snapshot_description-$NUMBER"
        else
            $EDITOR "/tmp/2backup_snapshot_description-$NUMBER"
        fi

        DESCRIPTION=$(cat "/tmp/2backup_snapshot_description-$NUMBER")
    fi

    TYPE="manual"
    DATE="$(date)"

    for i in $(seq 0 $(("${#SUBV[@]}"-1))); do
        mkdir "${SUBV_MNTPT[$i]}/.snapshots/$NUMBER"
        btrfs subvolume snapshot -r "${SUBV_MNTPT[$i]}" "${SUBV_MNTPT[$i]}/.snapshots/$NUMBER/snapshot"

        cat << EOF > "${SUBV_MNTPT[$i]}/.snapshots/$NUMBER/infos"
TYPE=${TYPE}
DATE="${DATE}"
DESCRIPTION="${DESCRIPTION}"
SUBV_MNTPT="${SUBV_MNTPT[$i]}"
EOF
        SHASUM_RAW=$(echo "$(cat ${SUBV_MNTPT[$i]}/.snapshots/$NUMBER/infos) $(date --rfc-3339=ns)" | shasum)
        IFS=' ' read -r -a SHASUM <<< "$SHASUM_RAW"; unset IFS
        echo "SHASUM=$SHASUM" >> "${SUBV_MNTPT[$i]}/.snapshots/$NUMBER/infos"
    done
}


snapshot_delete() {
    if [[ "$2" == "" ]]; then
        SNAPSHOT_HASH=$1
    else
        SNAPSHOT_ID=$1
        PROFILE=$2
    fi

    TO_DELETE=("")

    if [[ ! "$PROFILE" == "" ]]; then
        source /etc/2backup/profiles/$PROFILE

        for mountpoint in ${SUBV_MNTPT[@]}; do
            TO_DELETE+=("$mountpoint/.snapshots/$SNAPSHOT_ID")
        done

    fi

    TO_BE_DELETED=""
    for mountpoint in ${TO_DELETE[@]}; do
        TO_BE_DELETED+="'$mountpoint' "
    done

    read -p "Do you really want to delete these subvolumes: ${TO_BE_DELETED}? [y/N] " ASK

    if [[ "$ASK" == "y" || "$ASK" == "Y" ]]; then
        for path in ${TO_DELETE[@]}; do
            echo "Deleting ${path}..."
            btrfs subvolume delete $path/snapshot
            rm $path/infos
            rmdir $path
        done
        echo "Done."
    else
        echo "Deletion aborted."
    fi
}


# Main

init

echo

for i in "$@"; do
    case $i in

        profile)
            OPTION="profile"
            shift
            ;;

        snapshot)
            OPTION="snapshot"
            shift
            ;;

        rollback)
            OPTION="rollback"
            OBJECT="$2"
            shift; shift
            ;;

        create)
            create=true
            OBJECT="$2"
            shift; shift
            ;;

        delete)
            delete=true
            OBJECT="$2"
            shift; shift
            ;;

        list)
            list=true
            shift
            ;;

        show)
            show=true
            OBJECT="$2"
            shift; shift
            ;;

        mount)
            mount=true
            OBJECT="$2"
            shift; shift
            ;;

         umount)
            umount=true
            OBJECT="$2"
            shift; shift
            ;;

        -p)
            PROFILE="$2"
            shift; shift
            ;;

        -m)
            MESSAGE="$2"
            echo $MESSAGE
            shift; shift
            ;;

        -h|--help)
            usage
            exit
            ;;

#            *)
#                #>&2 echo "Unknown option $1"
#                #exit 1
#                ;;

    esac
done

set -e

case $OPTION in

    profile)
        if [[ "$create" == true ]]; then
            profile_create $OBJECT
        elif [[ "$delete" == true ]]; then
            profile_delete $OBJECT
        elif [[ "$show" == true ]]; then
            profile_show $OBJECT
        elif [[ "$list" == true ]]; then
            profile_list
        else
            >&2 echo "Unknown argument(s): $ARGS"
            >&2 echo "See -h|--help."
            exit 1
        fi
        ;;

    snapshot)
        if [[ "$create" == true ]]; then
            snapshot_create $OBJECT \"$MESSAGE\"
        elif [[ "$delete" == true ]]; then
            snapshot_delete $OBJECT $PROFILE
        elif [[ "$show" == true ]]; then
            snapshot_show $OBJECT $PROFILE
        elif [[ "$list" == true ]]; then
            snapshot_list $PROFILE
        elif [[ "$mount" == true ]]; then
            snapshot_mount $OBJECT $PROFILE
        elif [[ "$umount" == true ]]; then
            snapshot_umount $OBJECT $PROFILE
        else
            >&2 echo "Unknown argument(s): $ARGS"
            >&2 echo "See -h|--help."
            exit 1
        fi
        ;;

    rollback)
        rollback $OPTIONS $PROFILE
        ;;

    *)
        >&2 echo "Unknown option: '$ARGS'"
        exit 1
        ;;
esac