freedombone/src/freedombone-utils-backup

#!/bin/bash
#
# .---.                  .              .
# |                      |              |
# |--- .--. .-.  .-.  .-.|  .-. .--.--. |.-.  .-. .--.  .-.
# |    |   (.-' (.-' (   | (   )|  |  | |   )(   )|  | (.-'
# '    '     --'  --'  -' -  -' '  '   -' -'   -' '   -  --'
#
#                    Freedom in the Cloud
#
# Backup functions
#
# License
# =======
#
# Copyright (C) 2014-2016 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# whether a given site is being suspended during backup
SUSPENDED_SITE=

function suspend_site {
    # suspends a given website
    SUSPENDED_SITE="$1"
    nginx_dissite $SUSPENDED_SITE
    service nginx reload
}

function restart_site {
    # restarts a given website
    if [ ! $SUSPENDED_SITE ]; then
        return
    fi
    nginx_ensite $SUSPENDED_SITE
    service nginx reload
    SUSPENDED_SITE=
}

function configure_backup_key {
    if [[ $(is_completed $FUNCNAME) == "1" ]]; then
        return
    fi
    apt-get -yq install gnupg

    BACKUP_KEY_EXISTS=$(gpg_key_exists "root" "$MY_NAME (backup key)")
    if [[ $BACKUP_KEY_EXISTS == "yes" ]]; then
        return
    fi

    # Generate a GPG key for backups
    BACKUP_KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_NAME (backup key)")
    if [[ $BACKUP_KEY_EXISTS == "no" ]]; then
        echo 'Key-Type: 1' > /home/$MY_USERNAME/gpg-genkey.conf
        echo 'Key-Length: 4096' >> /home/$MY_USERNAME/gpg-genkey.conf
        echo 'Subkey-Type: 1' >> /home/$MY_USERNAME/gpg-genkey.conf
        echo 'Subkey-Length: 4096' >> /home/$MY_USERNAME/gpg-genkey.conf
        echo "Name-Real:  $MY_NAME" >> /home/$MY_USERNAME/gpg-genkey.conf
        echo "Name-Email: $MY_EMAIL_ADDRESS" >> /home/$MY_USERNAME/gpg-genkey.conf
        echo "Name-Comment: backup key" >> /home/$MY_USERNAME/gpg-genkey.conf
        echo 'Expire-Date: 0' >> /home/$MY_USERNAME/gpg-genkey.conf
        chown $MY_USERNAME:$MY_USERNAME /home/$MY_USERNAME/gpg-genkey.conf
        echo $'Backup key does not exist. Creating it.'
        su -c "gpg --batch --gen-key /home/$MY_USERNAME/gpg-genkey.conf" - $MY_USERNAME
        shred -zu /home/$MY_USERNAME/gpg-genkey.conf
        echo $'Checking that the Backup key was created'
        BACKUP_KEY_EXISTS=$(gpg_key_exists "$MY_USERNAME" "$MY_NAME (backup key)")
        if [[ $BACKUP_KEY_EXISTS == "no" ]]; then
            echo $'Backup key could not be created'
            exit 43382
        fi
    fi
    MY_BACKUP_KEY_ID=$(su -c "gpg --list-keys \"$MY_NAME (backup key)\" | grep 'pub '" - $MY_USERNAME | awk -F ' ' '{print $2}' | awk -F '/' '{print $2}')
    echo "Backup key: $MY_BACKUP_KEY_ID"
    MY_BACKUP_KEY=/home/$MY_USERNAME/backup_key
    su -c "gpg --output ${MY_BACKUP_KEY}_public.asc --armor --export $MY_BACKUP_KEY_ID" - $MY_USERNAME
    su -c "gpg --output ${MY_BACKUP_KEY}_private.asc --armor --export-secret-key $MY_BACKUP_KEY_ID" - $MY_USERNAME
    if [ ! -f ${MY_BACKUP_KEY}_public.asc ]; then
        echo 'Public backup key could not be exported'
        exit 36829
    fi
    if [ ! -f ${MY_BACKUP_KEY}_private.asc ]; then
        echo 'Private backup key could not be exported'
        exit 29235
    fi

    # import backup key to root user
    gpg --import --import ${MY_BACKUP_KEY}_public.asc
    gpg --allow-secret-key-import --import ${MY_BACKUP_KEY}_private.asc

    shred -zu ${MY_BACKUP_KEY}_public.asc
    shred -zu ${MY_BACKUP_KEY}_private.asc

    mark_completed $FUNCNAME
}

function backup_to_friends_servers {
    # update crontab
    echo '#!/bin/bash' > /etc/cron.daily/backuptofriends
    echo "if [ -f /usr/local/bin/${PROJECT_NAME}-backup-remote ]; then" >> /etc/cron.daily/backuptofriends
    echo "    /usr/local/bin/${PROJECT_NAME}-backup-remote" >> /etc/cron.daily/backuptofriends
    echo 'else' >> /etc/cron.daily/backuptofriends
    echo "    /usr/bin/${PROJECT_NAME}-backup-remote" >> /etc/cron.daily/backuptofriends
    echo 'fi' >> /etc/cron.daily/backuptofriends
    chmod +x /etc/cron.daily/backuptofriends
}

function backup_mount_drive {
    if [ $1 ]; then
        if [[ "$1" == "/dev/"* ]]; then
            USB_DRIVE=$1
        else
            USB_DRIVE=/dev/${1}1
        fi
    fi

    # get the admin user
    ADMIN_USERNAME=$(get_completion_param "Admin user")
    if [ $2 ]; then
        ADMIN_USERNAME=$2
    fi
    ADMIN_NAME=$(getent passwd $ADMIN_USERNAME | cut -d: -f5 | cut -d, -f1)

    if [ $3 ]; then
        RESTORE_APP=$3
    fi

    # check that the backup destination is available
    if [ ! -b $USB_DRIVE ]; then
        echo $"Please attach a USB drive"
        exit 1
    fi

    # unmount if already mounted
    umount -f $USB_MOUNT
    if [ ! -d $USB_MOUNT ]; then
        mkdir $USB_MOUNT
    fi
    if [ -f /dev/mapper/encrypted_usb ]; then
        rm -rf /dev/mapper/encrypted_usb
    fi
    cryptsetup luksClose encrypted_usb

    # mount the encrypted backup drive
    cryptsetup luksOpen $USB_DRIVE encrypted_usb
    if [ "$?" = "0" ]; then
        USB_DRIVE=/dev/mapper/encrypted_usb
    fi
    mount $USB_DRIVE $USB_MOUNT
    if [ ! "$?" = "0" ]; then
        echo $"There was a problem mounting the USB drive to $USB_MOUNT"
        rm -rf $USB_MOUNT
        exit 783452
    fi
}

function backup_unmount_drive {
    if [ $1 ]; then
        USB_DRIVE=${1}
        if [ $2 ]; then
            USB_MOUNT=${2}
        fi
    fi
    sync
    umount $USB_MOUNT
    if [ ! "$?" = "0" ]; then
        echo $"Unable to unmount the drive."
        rm -rf $USB_MOUNT
        exit 9
    fi
    rm -rf $USB_MOUNT
    if [[ $USB_DRIVE == /dev/mapper/encrypted_usb ]]; then
        echo $"Unmount encrypted USB"
        cryptsetup luksClose encrypted_usb
    fi
    if [ -f /dev/mapper/encrypted_usb ]; then
        rm -rf /dev/mapper/encrypted_usb
    fi
}

function backup_database_local_usb {
    if [ ${#DATABASE_PASSWORD} -lt 2 ]; then
        echo $"No MariaDB password was given"
        function_check restart_site
        restart_site
        exit 10
    fi
    if [ ! -d $USB_MOUNT/backup/${1} ]; then
        mkdir -p $USB_MOUNT/backup/${1}
    fi
    if [ ! -d $USB_MOUNT/backup/${1}data ]; then
        mkdir -p $USB_MOUNT/backup/${1}data
    fi
    local_database_dir=/root/temp${1}data
    if [ ! -d ${local_database_dir} ]; then
        mkdir -p ${local_database_dir}
    fi
    echo $"Obtaining ${1} database backup"
    mysqldump --lock-tables --password="$DATABASE_PASSWORD" ${1} > ${local_database_dir}/${1}.sql
    if [ -f ${local_database_dir}/${1}.sql ]; then
        if [ ! -s ${local_database_dir}/${1}.sql ]; then
            echo $"${1} database could not be saved"
            shred -zu ${local_database_dir}/*
            rm -rf ${local_database_dir}
            umount $USB_MOUNT
            rm -rf $USB_MOUNT
            restart_site
            exit 6835872
        fi
    else
        echo $"${1} database could not be dumped"
        rm -rf ${local_database_dir}
        umount $USB_MOUNT
        rm -rf $USB_MOUNT
        restart_site
        exit 738653
    fi
    echo $"Database dump was created for ${1}"
}

function set_obnam_client_name {
    # obnam can backup multiple machines with different domain names to
    # a repository. To be able to restore directories from different
    # machines we need to enforce a single client name for all backups
    echo '[config]' > /etc/obnam.conf
    echo "client-name = ${PROJECT_NAME}" >> /etc/obnam.conf
}

function backup_directory_to_usb {
    if [ ! -d ${1} ]; then
        echo $"WARNING: directory does not exist: ${1}"
    else
        BACKUP_KEY_EXISTS=$(gpg --list-keys "$ADMIN_NAME (backup key)")
        if [ ! "$?" = "0" ]; then
            echo $"Backup key could not be found"
            function_check restart_site
            restart_site
            exit 6
        fi
        MY_BACKUP_KEY_ID=$(gpg --list-keys "$ADMIN_NAME (backup key)" | grep 'pub ' | awk -F ' ' '{print $2}' | awk -F '/' '{print $2}')
        if [ ! -d $USB_MOUNT/backup/${2} ]; then
            mkdir -p $USB_MOUNT/backup/${2}
        fi
        set_obnam_client_name
        obnam force-lock -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
        obnam backup -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
        if [[ $ENABLE_BACKUP_VERIFICATION == "yes" ]]; then
            obnam verify -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID ${1}
            if [ ! "$?" = "0" ]; then
                umount $USB_MOUNT
                rm -rf $USB_MOUNT
                if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
                    shred -zu ${1}/*
                    rm -rf ${1}
                fi
                function_check restart_site
                restart_site
                exit 683252
            fi
        fi
        obnam forget --keep=30d -r $USB_MOUNT/backup/${2} --encrypt-with $MY_BACKUP_KEY_ID
        if [ ! "$?" = "0" ]; then
            umount $USB_MOUNT
            rm -rf $USB_MOUNT
            if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
                shred -zu ${1}/*
                rm -rf ${1}
            fi
            function_check restart_site
            restart_site
            exit 7
        fi
        if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
            shred -zu ${1}/*
            rm -rf ${1}
        fi
    fi
}

function restore_directory_from_usb {
    if [ ! -d ${1} ]; then
        mkdir ${1}
    fi
    set_obnam_client_name
    obnam restore -r $USB_MOUNT/backup/${2} --to ${1}
}

function restore_directory_from_friend {
    if [ ! -d ${1} ]; then
        mkdir ${1}
    fi
    set_obnam_client_name
    obnam restore -r $SERVER_DIRECTORY/backup/${2} --to ${1}
}

function backup_database_to_usb {
    database_name=$1
    local_database_dir=/root/temp${1}data
    backup_database_local_usb ${database_name}
    if [ ! -f ${local_database_dir}/${1}.sql ]; then
        echo $"Error backing up ${1} database to ${local_database_dir}/${1}.sql"
        exit 62383
    fi
    backup_directory_to_usb ${local_database_dir} ${database_name}data
}

# after user files have been restored permissions may need to be set
function set_user_permissions {
    echo $"Setting permissions"
    for d in /home/*/ ; do
        USERNAME=$(echo "$d" | awk -F '/' '{print $3}')
        if [[ $(is_valid_user "$USERNAME") == "1" ]]; then
            chown -R $USERNAME:$USERNAME /home/$USERNAME
        fi
    done
}

function backup_directory_to_friend {
    BACKUP_KEY_EXISTS=$(gpg --list-keys "$ADMIN_NAME (backup key)")
    if [ ! "$?" = "0" ]; then
        echo $"Backup key could not be found"
        function_check restart_site
        restart_site
        exit 43382
    fi
    ADMIN_BACKUP_KEY_ID=$(gpg --list-keys "$ADMIN_NAME (backup key)" | grep 'pub ' | awk -F ' ' '{print $2}' | awk -F '/' '{print $2}')
    if [ ! -d $SERVER_DIRECTORY/backup/${2} ]; then
        mkdir -p $SERVER_DIRECTORY/backup/${2}
    fi
    set_obnam_client_name
    obnam force-lock -r $SERVER_DIRECTORY/backup/${2} --encrypt-with ${ADMIN_BACKUP_KEY_ID} ${1}
    obnam backup -r $SERVER_DIRECTORY/backup/${2} --encrypt-with ${ADMIN_BACKUP_KEY_ID} ${1}
    if [[ $ENABLE_VERIFICATION == "yes" ]]; then
        obnam verify -r $SERVER_DIRECTORY/backup/${2} --encrypt-with ${ADMIN_BACKUP_KEY_ID} ${1}
        if [ ! "$?" = "0" ]; then
            if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
                shred -zu /root/temp${2}/*
                rm -rf /root/temp${2}
            fi
            # Send a warning email
            echo "Unable to verify ${2}" | mail -s "${PROJECT_NAME} backup to friends" ${ADMIN_EMAIL_ADDRESS}
            function_check restart_site
            restart_site
            exit 953
        fi
    fi
    obnam forget --keep=30d -r $SERVER_DIRECTORY/backup/${2} --encrypt-with ${ADMIN_BACKUP_KEY_ID}
    if [ ! "$?" = "0" ]; then
        if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
            shred -zu /root/temp${2}/*
            rm -rf /root/temp${2}
        fi
        # Send a warning email
        echo "Unable to backup ${2}" | mail -s "${PROJECT_NAME} backup to friends" ${ADMIN_EMAIL_ADDRESS}
        function_check restart_site
        restart_site
        exit 853
    fi
    if [[ ${1} == "/root/temp"* || ${1} == *"tempbackup" ]]; then
        shred -zu /root/temp${2}/*
        rm -rf /root/temp${2}
    fi
}

function backup_database_remote {
    if [ ${#DATABASE_PASSWORD} -lt 2 ]; then
        echo $"No MariaDB password was given"
        function_check restart_site
        restart_site
        exit 5783
    fi
    if [ ! -d $SERVER_DIRECTORY/backup/${1} ]; then
        mkdir -p $SERVER_DIRECTORY/backup/${1}
    fi
    if [ ! -d $SERVER_DIRECTORY/backup/${1}data ]; then
        mkdir -p $SERVER_DIRECTORY/backup/${1}data
    fi
    local_database_dir=/root/temp${1}data
    if [ ! -d ${local_database_dir} ]; then
        mkdir -p ${local_database_dir}
    fi
    echo "Obtaining ${1} database backup"
    mysqldump --password="$DATABASE_PASSWORD" ${1} > ${local_database_dir}/${1}.sql
    if [ -f ${local_database_dir}/${1}.sql ]; then
        if [ ! -s ${local_database_dir}/${1}.sql ]; then
            echo $"${1} database could not be saved"
            shred -zu ${local_database_dir}/*
            rm -rf ${local_database_dir}
            # Send a warning email
            echo $"Unable to export ${1} database" | mail -s $"${PROJECT_NAME} backup to friends" $ADMIN_EMAIL_ADDRESS
            function_check restart_site
            restart_site
            exit 5738
        fi
    else
        echo $"${1} database could not be dumped"
        rm -rf ${local_database_dir}
        # Send a warning email
        echo $"Unable to dump ${1} database" | mail -s $"${PROJECT_NAME} backup to friends" $ADMIN_EMAIL_ADDRESS
        function_check restart_site
        restart_site
        exit 3687
    fi
}

function backup_database_to_friend {
    database_name=$1
    backup_database_remote $database_name
    backup_directory_to_friend /root/temp${database_name}data ${database_name}data
}

function backup_apps {
    localremote=$1

    BACKUP_APPS_COMPLETED=()

    detect_installable_apps
    get_apps_installed_names

    for app_name in "${APPS_INSTALLED_NAMES[@]}"
    do
        echo $"Backup ${app_name}"
        app_load_variables ${app_name}
        function_check backup_${localremote}_${app_name}
        backup_${localremote}_${app_name}
        BACKUP_APPS_COMPLETED+=("${app_name}")
        echo $"Backup ${app_name} completed"
    done
}

function restore_apps {
    localremote=$1
    RESTORE_APP=$2

    RESTORE_APPS_COMPLETED=()

    detect_installable_apps
    get_apps_installed_names

    for app_name in "${APPS_INSTALLED_NAMES[@]}"
    do
        confirm_restore=
        if [ ! $2 ]; then
            confirm_restore=1
        else
            if [[ "$RESTORE_APP" == "$app_name" || "$RESTORE_APP" == "all" ]]; then
                confirm_restore=1
            fi
        fi
        if [ $confirm_restore ]; then
            echo $"Restoring ${app_name}"
            app_load_variables ${app_name}
            function_check restore_${localremote}_${app_name}
            restore_${localremote}_${app_name}
            RESTORE_APPS_COMPLETED+=("${app_name}")
            echo $"Restored ${app_name}"
        fi
    done
}

function restore_database_from_friend {
    DATABASE_PASSWORD=
    RESTORE_SUBDIR="root"

    if [ -d $SERVER_DIRECTORY/backup/${1} ]; then
        echo $"Restoring ${1} database"
        local_database_dir=/root/temp${1}data
        restore_directory_from_friend ${local_database_dir} ${1}data
        if [ ! -f ${local_database_dir}/${RESTORE_SUBDIR}/temp${1}data/${1}.sql ]; then
            echo $"Unable to restore ${1} database"
            rm -rf ${local_database_dir}
            exit 503
        fi
        mysqlsuccess=$(mysql -u root --password="$DATABASE_PASSWORD" ${1} -o < ${local_database_dir}/${RESTORE_SUBDIR}/temp${1}data/${1}.sql)
        if [ ! "$?" = "0" ]; then
            echo "$mysqlsuccess"
            exit 964
        fi
        shred -zu ${local_database_dir}/${RESTORE_SUBDIR}/temp${1}data/*
        rm -rf ${local_database_dir}
        echo $"Restoring ${1} installation"
        restore_directory_from_friend /root/temp${1} ${1}
        RESTORE_SUBDIR="var"
        if [ ${1} ]; then
            if [ -d /var/www/${2}/htdocs ]; then
                if [ -d /root/temp${1}/${RESTORE_SUBDIR}/www/${2}/htdocs ]; then
                    rm -rf /var/www/${2}/htdocs
                    mv /root/temp${1}/${RESTORE_SUBDIR}/www/${2}/htdocs /var/www/${2}/
                    if [ ! "$?" = "0" ]; then
                        exit 683
                    fi
                    if [ -d /etc/letsencrypt/live/${2} ]; then
                        ln -s /etc/letsencrypt/live/${2}/privkey.pem /etc/ssl/private/${2}.key
                        ln -s /etc/letsencrypt/live/${2}/fullchain.pem /etc/ssl/certs/${2}.pem
                    else
                        # Ensure that the bundled SSL cert is being used
                        if [ -f /etc/ssl/certs/${2}.bundle.crt ]; then
                            sed -i "s|${2}.crt|${2}.bundle.crt|g" /etc/nginx/sites-available/${2}
                        fi
                    fi
                fi
            fi
        fi
    fi
}

function restore_database {
    RESTORE_SUBDIR="root"

    if [ -d $USB_MOUNT/backup/${1} ]; then
        echo $"Restoring ${1} database"
        local_database_dir=/root/temp${1}data
        function_check restore_directory_from_usb
        restore_directory_from_usb "${local_database}" "${1}data"
        if [ ! -f /root/temp${1}data/${RESTORE_SUBDIR}/temp${1}data/${1}.sql ]; then
            echo $"Unable to restore ${1} database"
            rm -rf ${local_database}
            function_check set_user_permissions
            set_user_permissions
            function_check backup_unmount_drive
            backup_unmount_drive
            exit 503
        fi
        mysqlsuccess=$(mysql -u root --password="$DATABASE_PASSWORD" ${1} -o < ${local_database}/${RESTORE_SUBDIR}/temp${1}data/${1}.sql)
        if [ ! "$?" = "0" ]; then
            echo "$mysqlsuccess"
            function_check set_user_permissions
            set_user_permissions
            function_check set_user_permissions
            backup_unmount_drive
            exit 964
        fi
        shred -zu ${local_database}/${RESTORE_SUBDIR}/temp${1}data/*
        rm -rf ${local_database}
        echo $"Restoring ${1} installation"
        if [ ! -d /root/temp${1} ]; then
            mkdir /root/temp${1}
        fi
        function_check restore_directory_from_usb
        restore_directory_from_usb "/root/temp${1}" "${1}"
        RESTORE_SUBDIR="var"
        if [ ${2} ]; then
            if [ -d /var/www/${2}/htdocs ]; then
                if [ -d /root/temp${1}/${RESTORE_SUBDIR}/www/${2}/htdocs ]; then
                    rm -rf /var/www/${2}/htdocs
                    mv /root/temp${1}/${RESTORE_SUBDIR}/www/${2}/htdocs /var/www/${2}/
                    if [ ! "$?" = "0" ]; then
                        set_user_permissions
                        backup_unmount_drive
                        exit 683
                    fi
                    if [ -d /etc/letsencrypt/live/${2} ]; then
                        ln -s /etc/letsencrypt/live/${2}/privkey.pem /etc/ssl/private/${2}.key
                        ln -s /etc/letsencrypt/live/${2}/fullchain.pem /etc/ssl/certs/${2}.pem
                    else
                        # Ensure that the bundled SSL cert is being used
                        if [ -f /etc/ssl/certs/${2}.bundle.crt ]; then
                            sed -i "s|${2}.crt|${2}.bundle.crt|g" /etc/nginx/sites-available/${2}
                        fi
                    fi
                fi
            fi
        fi
    fi
}

function valid_backup_destination {
    # used to check whether any additional backup directories clash with
    # exiting apps
    destination_dir="$1"
    is_valid="yes"

    available_variants_list=()
    available_system_variants

    item_in_array "${destination_dir}" "${available_variants_list[@]}"
    if [[ $? != 0 ]]; then
        is_valid="no"
    fi

    echo $is_valid
}

function backup_extra_directories {
    if [ ! -f $BACKUP_EXTRA_DIRECTORIES ]; then
        return
    fi

    backup_type="$1"

    echo $"Backing up some additional directories"
    while read backup_line
    do
        backup_dir=$(echo "$backup_line" | awk -F ',' '{print $1}' | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
        if [ -d "$backup_dir" ]; then
            destination_dir=$(echo "$backup_line" | awk -F ',' '{print $2}' | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')
            if [[ $(valid_backup_destination "$destination_dir") == "yes" ]]; then
                if [[ $backup_type == "local" ]]; then
                    backup_directory_to_usb "$backup_dir" "$destination_dir"
                else
                    backup_directory_to_friend "$backup_dir" "$destination_dir"
                fi
            else
                echo $"WARNING: The backup directory $destination_dir is already used."
                echo $"Choose a different destination name for backing up $backup_dir"
            fi
        else
            echo $"WARNING: Directory $backup_dir does not exist"
        fi
    done <$BACKUP_EXTRA_DIRECTORIES
}

# NOTE: deliberately no exit 0