p7cq · November 5, 2024 10:14
diff --git a/Arch_Linux_Root_On_ZFS.md b/Arch_Linux_Root_On_ZFS.md
diff --git a/zsrs b/zsrs
 #!/usr/bin/env bash

 #
 # zsrs, a ZFS snapshot/rollback script
 #
 # @p7cq

 ss_to_keep=0
 root_pool="rpool/ROOT/default"
 root_ss="/.zfs/snapshot"
 boot_ss="/local/.boot/snapshot"
 boot_part="/boot"
 loader_file="${boot_part}/loader/entries/arch.conf"
 action=${1}
 ss_date=$(/usr/bin/date +"%A %B %e, %Y %k:%M:%S")
 ss_manifest_file=".manifest"

 function _help() {
    local topic=${1}
    [[ ${topic} == "usage" ]] && \
    /usr/bin/echo -e "usage:\n \
    zsrs delete [snapshot id]   remove all snapshots keeping only the last ${ss_to_keep}\n \
    zsrs snapshot [comment]     snapshot the system; comment max length 64 chars\n \
    zsrs rollback [snapshot id] rollback the system to the previous state (the last snapshot)\n \
    zsrs list                   list snapshots\n \
    zsrs help                   usage" && \
    exit 0
 }

 function _boot_ss() {
    [[ -d "${1}" ]] && /usr/bin/echo "\e[97m\e[1mboot snapshot id is undefined\e[0m" && exit 1
    local ss_id="${1}"
    /usr/bin/mkdir ${boot_ss}/${ss_id}
    /usr/bin/chmod 700 ${boot_ss}/${ss_id}
    /usr/bin/echo ${ss_manifest} > ${boot_ss}/${ss_id}/${ss_manifest_file}
    /usr/bin/rsync -avzq --delete ${boot_part}/ ${boot_ss}/${ss_id}/BOOT
 }

 function _boot_rb() {
    local ss_id="${1}"
    [[ -z "${ss_id}" ]] && /usr/bin/echo "\e[97m\e[1mboot snapshot id is undefined\e[0m" && exit 1
    /usr/bin/echo -e "\e[97m\e[1moverwriting boot partition at \e[0m\e[33m\e[1m${boot_part}\e[0m"
    /usr/bin/rsync -avzq --delete ${boot_ss}/${ss_id}/BOOT/ ${boot_part}
    IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${ss_id}/${ss_manifest_file})"
    local title="title Arch Linux (${ss_id}: ${manifest[0]} ${manifest[1]})"
    /usr/bin/sed -i "1 s/^.*$/${title}/g" ${loader_file}
 }

 function _ss_manifest() {
    local comment="${1}"
    ss_manifest="^${ss_date}"
    [[ -z "${comment}" ]] && comment="snapshot"
    comment=$(/usr/bin/sed 's/\^/_/g' <<< ${comment})
    ss_manifest="${comment:0:64}${ss_manifest}"
 }

 function _restrict() {
    if (( ${EUID:-0} || "$(/usr/bin/id -u)" )); then
        /usr/bin/echo -e "\e[97m\e[1myou must be root to do this\e[0m"
        exit 1
    fi
 }

 _restrict

 declare -a args=("delete" "d" "snapshot" "s" "rollback" "r" "list" "l" "help" "h")
 [[ "$#" = "0" ]] || [[ ! " ${args[@]} " =~ " ${1} " ]] && _help "usage" && exit 0

 [[ ! -d ${root_ss} ]] && /usr/bin/echo "${root_ss} does not exist" && exit 1
 [[ ! -d ${boot_ss} ]] && /usr/bin/echo "${boot_ss} does not exist" && exit 1

 ss_count=$(/usr/bin/ls ${boot_ss} | /usr/bin/wc -l)

 if [[ ${action} == "delete" ]] || [[ ${action} == "d" ]]; then
    ss_id=${2}
    case "${ss_to_keep}" in
      0)
        what=" \e[0m\e[33m\e[1mall\e[0m\e[97m\e[1m snapshots"
        ;;
      *)
        what=" all snapshots and keep the last \e[0m\e[33m\e[1m${ss_to_keep}\e[0m\e[97m\e[1m"
        ;;
    esac
    if (( $# == 1 )); then
        /usr/bin/echo -en "\e[97m\e[1mdelete${what}? (yes/no): \e[0m" && read
        [[ "${REPLY}" != "yes" ]] && exit 0
    fi
    if [[ ! -z "${ss_id}" ]]; then
        re='^[0-9]+$'
        [[ ! ${ss_id} =~ ${re} ]] && /usr/bin/echo -e "\e[97m\e[1ma positive integer is expected (see \e[0m\e[33m\e[1mzsrs list\e[0m)\e[0m" && exit 1
        [[ ! -d "${root_ss}/${ss_id}" ]] && /usr/bin/echo -e "\e[97m\e[1mno such snapshot\e[0m" && exit 1
        /usr/bin/zfs destroy ${root_pool}@${ss_id}
        /usr/bin/rm -rf ${boot_ss}/${ss_id}
        exit 0
    fi

    if (( ss_count > ss_to_keep )); then
        lwm=$(/usr/bin/ls ${root_ss} | /usr/bin/sort -n | /usr/bin/head -1)
        hwm=$(/usr/bin/ls ${root_ss} | /usr/bin/sort -nr | /usr/bin/head -1)
        end=$((hwm-ss_to_keep))
        if [ ! -z "${lwm}" ] && [ ! -z "${hwm}" ]; then
            for ((s=lwm; s<=end; s++)) do
                [[ ! -d "${boot_ss}/${s}" ]] && continue
                /usr/bin/zfs destroy ${root_pool}@${s}
                /usr/bin/rm -rf ${boot_ss}/${s}
            done
        fi
    else
        /usr/bin/echo -e "\e[97m\e[1mless than \e[0m\e[33m\e[1m$((${ss_to_keep}+1))\e[0m\e[97m\e[1m snapshots, none deleted\e[0m"
    fi
    exit 0
 fi

 if [[ ${action} == "snapshot" ]] || [[ ${action} == "s" ]]; then
    ss_id=$(($(/usr/bin/ls ${boot_ss} | /usr/bin/sort -nr | /usr/bin/head -1)+1))
    _ss_manifest "${2}"
    _boot_ss ${ss_id}
    /usr/bin/zfs snapshot ${root_pool}@${ss_id}
    /usr/bin/echo -e "\e[97m\e[1mcreated snapshot with id \e[0m\e[33m\e[1m${ss_id}\e[0m"
    exit 0
 fi

 if [[ ${action} == "rollback" ]] || [[ ${action} == "r" ]]; then
    ss_id=${2}
    last_ss=$(/usr/bin/ls ${boot_ss} | /usr/bin/sort -nr | /usr/bin/head -1)

    if [[ ! -z "${ss_id}" ]]; then
        ([[ "${ss_id}" == "0" ]] || [[ ! -d "${boot_ss}/${ss_id}" ]] || [[ ! -d "${root_ss}/${ss_id}" ]]) && /usr/bin/echo -e "\e[97m\e[1mno such snapshot\e[0m" && exit 1
        re='^[0-9]+$'
        [[ ! ${ss_id} =~ ${re} ]] && /usr/bin/echo  -e "\e[97m\e[1ma positive integer is expected\e[0m" && exit 1
    else
        ss_id=${last_ss}
    fi

    IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${ss_id}/${ss_manifest_file})"
    /usr/bin/echo -e "\e[97m\e[1mrolling back to snapshot \e[0m\e[33m\e[1m${ss_id}\e[0m\e[97m\e[1m: \e[0m\e[33m\e[1m${manifest[0]}\e[97m\e[1m taken on \e[0m\e[33m\e[1m${manifest[1]}\e[0m"
    /usr/bin/echo -en "\e[97m\e[1ma reboot will be required, proceed? (yes/no): \e[0m" && read
    [[ "${REPLY}" != "yes" ]] && exit 0
    destroy_recent=""
    if (( ss_id < last_ss )); then
      destroy_recent="-R"
      for ((s=last_ss; s>ss_id; s--)); do
        more_recent_ss="${boot_ss}/${s}"
        [[ -d "${more_recent_ss}" ]] && /usr/bin/rm -rf ${more_recent_ss}
      done
    fi
    /usr/bin/zfs rollback ${destroy_recent} ${root_pool}@${ss_id}
    _boot_rb ${ss_id}
    /usr/bin/echo -e "\e[97m\e[1msnapshot \e[0m\e[33m\e[1m${manifest[0]}\e[0m\e[97m\e[1m is now the active system, rebooting...\e[0m"
    sleep 2
    /usr/bin/systemctl reboot
 fi

 if [[ ${action} == "help" ]] || [[ ${action} == "h" ]]; then
    _help "usage"
    exit 0
 fi

 if [[ ${action} == "list" ]] || [[ ${action} == "l" ]]; then
    if ((ss_count == 0)); then 
        /usr/bin/echo -e "\e[97m\e[1mno snapshots available\e[0m"
        exit 0
    fi
    for id in $(/usr/bin/ls ${boot_ss} | /usr/bin/sort -nr); do
        IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${id}/${ss_manifest_file})"
        /usr/bin/echo -e "\e[33m\e[1m${id}\e[0m^\e[97m\e[1m${manifest[0]}^${manifest[1]}\e[0m"
    done | /usr/bin/column -t -N ID,COMMENT,DATE -s "^"
    exit 0
 fi
	#!/usr/bin/env bash

	#
	# zsrs, a ZFS snapshot/rollback script
	#
	# @p7cq

	ss_to_keep=0
	root_pool="rpool/ROOT/default"
	root_ss="/.zfs/snapshot"
	boot_ss="/local/.boot/snapshot"
	boot_part="/boot"
	loader_file="${boot_part}/loader/entries/arch.conf"
	action=${1}
	ss_date=$(/usr/bin/date +"%A %B %e, %Y %k:%M:%S")
	ss_manifest_file=".manifest"

	function _help() {
	local topic=${1}
	[[ ${topic} == "usage" ]] && \
	/usr/bin/echo -e "usage:\n \
	zsrs delete [snapshot id] remove all snapshots keeping only the last ${ss_to_keep}\n \
	zsrs snapshot [comment] snapshot the system; comment max length 64 chars\n \
	zsrs rollback [snapshot id] rollback the system to the previous state (the last snapshot)\n \
	zsrs list list snapshots\n \
	zsrs help usage" && \
	exit 0
	}

	function _boot_ss() {
	[[ -d "${1}" ]] && /usr/bin/echo "\e[97m\e[1mboot snapshot id is undefined\e[0m" && exit 1
	local ss_id="${1}"
	/usr/bin/mkdir ${boot_ss}/${ss_id}
	/usr/bin/chmod 700 ${boot_ss}/${ss_id}
	/usr/bin/echo ${ss_manifest} > ${boot_ss}/${ss_id}/${ss_manifest_file}
	/usr/bin/rsync -avzq --delete ${boot_part}/ ${boot_ss}/${ss_id}/BOOT
	}

	function _boot_rb() {
	local ss_id="${1}"
	[[ -z "${ss_id}" ]] && /usr/bin/echo "\e[97m\e[1mboot snapshot id is undefined\e[0m" && exit 1
	/usr/bin/echo -e "\e[97m\e[1moverwriting boot partition at \e[0m\e[33m\e[1m${boot_part}\e[0m"
	/usr/bin/rsync -avzq --delete ${boot_ss}/${ss_id}/BOOT/ ${boot_part}
	IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${ss_id}/${ss_manifest_file})"
	local title="title Arch Linux (${ss_id}: ${manifest[0]} ${manifest[1]})"
	/usr/bin/sed -i "1 s/^.*$/${title}/g" ${loader_file}
	}

	function _ss_manifest() {
	local comment="${1}"
	ss_manifest="^${ss_date}"
	[[ -z "${comment}" ]] && comment="snapshot"
	comment=$(/usr/bin/sed 's/\^/_/g' <<< ${comment})
	ss_manifest="${comment:0:64}${ss_manifest}"
	}

	function _restrict() {
	if (( ${EUID:-0} \|\| "$(/usr/bin/id -u)" )); then
	/usr/bin/echo -e "\e[97m\e[1myou must be root to do this\e[0m"
	exit 1
	fi
	}

	_restrict

	declare -a args=("delete" "d" "snapshot" "s" "rollback" "r" "list" "l" "help" "h")
	[[ "$#" = "0" ]] \|\| [[ ! " ${args[@]} " =~ " ${1} " ]] && _help "usage" && exit 0

	[[ ! -d ${root_ss} ]] && /usr/bin/echo "${root_ss} does not exist" && exit 1
	[[ ! -d ${boot_ss} ]] && /usr/bin/echo "${boot_ss} does not exist" && exit 1

	ss_count=$(/usr/bin/ls ${boot_ss} \| /usr/bin/wc -l)

	if [[ ${action} == "delete" ]] \|\| [[ ${action} == "d" ]]; then
	ss_id=${2}
	case "${ss_to_keep}" in
	0)
	what=" \e[0m\e[33m\e[1mall\e[0m\e[97m\e[1m snapshots"
	;;
	*)
	what=" all snapshots and keep the last \e[0m\e[33m\e[1m${ss_to_keep}\e[0m\e[97m\e[1m"
	;;
	esac
	if (( $# == 1 )); then
	/usr/bin/echo -en "\e[97m\e[1mdelete${what}? (yes/no): \e[0m" && read
	[[ "${REPLY}" != "yes" ]] && exit 0
	fi
	if [[ ! -z "${ss_id}" ]]; then
	re='^[0-9]+$'
	[[ ! ${ss_id} =~ ${re} ]] && /usr/bin/echo -e "\e[97m\e[1ma positive integer is expected (see \e[0m\e[33m\e[1mzsrs list\e[0m)\e[0m" && exit 1
	[[ ! -d "${root_ss}/${ss_id}" ]] && /usr/bin/echo -e "\e[97m\e[1mno such snapshot\e[0m" && exit 1
	/usr/bin/zfs destroy ${root_pool}@${ss_id}
	/usr/bin/rm -rf ${boot_ss}/${ss_id}
	exit 0
	fi

	if (( ss_count > ss_to_keep )); then
	lwm=$(/usr/bin/ls ${root_ss} \| /usr/bin/sort -n \| /usr/bin/head -1)
	hwm=$(/usr/bin/ls ${root_ss} \| /usr/bin/sort -nr \| /usr/bin/head -1)
	end=$((hwm-ss_to_keep))
	if [ ! -z "${lwm}" ] && [ ! -z "${hwm}" ]; then
	for ((s=lwm; s<=end; s++)) do
	[[ ! -d "${boot_ss}/${s}" ]] && continue
	/usr/bin/zfs destroy ${root_pool}@${s}
	/usr/bin/rm -rf ${boot_ss}/${s}
	done
	fi
	else
	/usr/bin/echo -e "\e[97m\e[1mless than \e[0m\e[33m\e[1m$((${ss_to_keep}+1))\e[0m\e[97m\e[1m snapshots, none deleted\e[0m"
	fi
	exit 0
	fi

	if [[ ${action} == "snapshot" ]] \|\| [[ ${action} == "s" ]]; then
	ss_id=$(($(/usr/bin/ls ${boot_ss} \| /usr/bin/sort -nr \| /usr/bin/head -1)+1))
	_ss_manifest "${2}"
	_boot_ss ${ss_id}
	/usr/bin/zfs snapshot ${root_pool}@${ss_id}
	/usr/bin/echo -e "\e[97m\e[1mcreated snapshot with id \e[0m\e[33m\e[1m${ss_id}\e[0m"
	exit 0
	fi

	if [[ ${action} == "rollback" ]] \|\| [[ ${action} == "r" ]]; then
	ss_id=${2}
	last_ss=$(/usr/bin/ls ${boot_ss} \| /usr/bin/sort -nr \| /usr/bin/head -1)

	if [[ ! -z "${ss_id}" ]]; then
	([[ "${ss_id}" == "0" ]] \|\| [[ ! -d "${boot_ss}/${ss_id}" ]] \|\| [[ ! -d "${root_ss}/${ss_id}" ]]) && /usr/bin/echo -e "\e[97m\e[1mno such snapshot\e[0m" && exit 1
	re='^[0-9]+$'
	[[ ! ${ss_id} =~ ${re} ]] && /usr/bin/echo -e "\e[97m\e[1ma positive integer is expected\e[0m" && exit 1
	else
	ss_id=${last_ss}
	fi

	IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${ss_id}/${ss_manifest_file})"
	/usr/bin/echo -e "\e[97m\e[1mrolling back to snapshot \e[0m\e[33m\e[1m${ss_id}\e[0m\e[97m\e[1m: \e[0m\e[33m\e[1m${manifest[0]}\e[97m\e[1m taken on \e[0m\e[33m\e[1m${manifest[1]}\e[0m"
	/usr/bin/echo -en "\e[97m\e[1ma reboot will be required, proceed? (yes/no): \e[0m" && read
	[[ "${REPLY}" != "yes" ]] && exit 0
	destroy_recent=""
	if (( ss_id < last_ss )); then
	destroy_recent="-R"
	for ((s=last_ss; s>ss_id; s--)); do
	more_recent_ss="${boot_ss}/${s}"
	[[ -d "${more_recent_ss}" ]] && /usr/bin/rm -rf ${more_recent_ss}
	done
	fi
	/usr/bin/zfs rollback ${destroy_recent} ${root_pool}@${ss_id}
	_boot_rb ${ss_id}
	/usr/bin/echo -e "\e[97m\e[1msnapshot \e[0m\e[33m\e[1m${manifest[0]}\e[0m\e[97m\e[1m is now the active system, rebooting...\e[0m"
	sleep 2
	/usr/bin/systemctl reboot
	fi

	if [[ ${action} == "help" ]] \|\| [[ ${action} == "h" ]]; then
	_help "usage"
	exit 0
	fi

	if [[ ${action} == "list" ]] \|\| [[ ${action} == "l" ]]; then
	if ((ss_count == 0)); then
	/usr/bin/echo -e "\e[97m\e[1mno snapshots available\e[0m"
	exit 0
	fi
	for id in $(/usr/bin/ls ${boot_ss} \| /usr/bin/sort -nr); do
	IFS='^' read -ra manifest <<< "$(/usr/bin/cat ${boot_ss}/${id}/${ss_manifest_file})"
	/usr/bin/echo -e "\e[33m\e[1m${id}\e[0m^\e[97m\e[1m${manifest[0]}^${manifest[1]}\e[0m"
	done \| /usr/bin/column -t -N ID,COMMENT,DATE -s "^"
	exit 0
	fi