#!/bin/sh
#
# Copyright (c) 2017-2019 Aaron LI <aly@aaronly.me>
# MIT License
#
# Tool to update a DragonFly BSD system using binary releases or
# snapshot builds.
#

# Exit immediately if any untested command fails in non-interactive mode
set -e
# Exit with an error when an undefined variable is referenced
set -u

DEBUG=${DEBUG:-""}

VERSION="0.1.5"
NAME="dfly-update"
TOOLDIR="${0%/*}"
PREFIX="${PREFIX:-${TOOLDIR}}"
CONFIGFILE="${PREFIX}/${NAME}.conf"

#
# Error Codes
#

EC_OS=10
EC_TMPFILE=11
EC_MD5=12
EC_ARGS=13
EC_FETCH=14
EC_MOUNT=15
EC_UMOUNT=16
EC_VN=17
EC_TAR=18
EC_MTREE=19
EC_CPDUP=20
EC_NOFILE=21
EC_PW=22


#
# Default Configurations
#

# Path to the cpdup(1) executable
CPDUP="/bin/cpdup"
# Temporary directory to cache the image, etc, ...
CACHE_DIR="/var/tmp/${NAME}"
# Directory to mount the system image
MNT_DIR="/mnt/${NAME}"
# Backup directory
BACK_DIR="/var/backups/${NAME}"

# List of files/directories to be installed
INSTALL_LIST='
    COPYRIGHT
    bin
    boot
    compat
    lib
    libexec
    rescue
    sbin
    usr/Makefile
    usr/bin
    usr/games
    usr/include
    usr/lib
    usr/libdata
    usr/libexec
    usr/sbin
    usr/share
    var/msgs
    var/yp
'

# Ignored files to be kept from overriding by the upgrade.
FILES_IGNORE='
    /boot/loader.conf
    /etc/crypttab
    /etc/fstab
    /etc/group
    /etc/localtime
    /etc/login.conf.db
    /etc/master.passwd
    /etc/motd
    /etc/passwd
    /etc/pwd.db
    /etc/rc.conf
    /etc/spwd.db
    /var/db/locate.database
    /var/mail/root
'
# Filename suffix for newly installed files that need (manual) merge.
NEW_SUF="__new__"


#
# Helper Functions
#

debug() {
    # Add "|| true" to work with "set -e"
    [ -n "${DEBUG}" ] && echo "DEBUG: $@" >&2 || true
}

log() {
    echo "$@" >&2
}

warn() {
    echo "WARNING: $@" >&2
}

error() {
    local ec="$1"
    shift
    echo "ERROR: $@" >&2
    exit ${ec}
}

# Mount the downloaded image (IMG file)
#
# mount_image(imgfile, mntpnt)
#
mount_image() {
    local imgfile="$1"
    local mntpnt="$2"
    local vn
    [ -d "${mntpnt}" ] || mkdir "${mntpnt}"
    echo "Mounting image ${imgfile} to ${mntpnt} ..."
    vn=$(vnconfig -c vn ${imgfile}) || exit ${EC_VN}
    mount -r /dev/${vn}s2a ${mntpnt} &&
        echo "DONE" ||
        exit ${EC_MOUNT}
}

# Get the vn device name of the mounted image
get_vn_devname() {
    local mntpnt="$1"
    local dev=$(mount | fgrep "${mntpnt}" | cut -d' ' -f 1 | cut -d'/' -f 3)
    echo ${dev%s??}
}

# Umount the image
#
# umount_image(mntpnt)
#
umount_image() {
    local mntpnt="$1"
    local vn=$(get_vn_devname ${mntpnt})
    echo -n "Umounting image from ${mntpnt} ... "
    umount ${mntpnt} && echo "DONE" || exit ${EC_UMOUNT}
    echo "Disable and unconfigure VN device ${vn} ... "
    vnconfig -u ${vn} &&
        echo "DONE" ||
        exit ${EC_VN}
}

# Backup the old kernel
backup_kernel() {
    local kerndir="/boot/kernel"
    local oldkerndir="${kerndir}.old"
    [ -d "${oldkerndir}" ] && {
        rm -r ${oldkerndir}
        warn "Removed previously backed kernel: ${oldkerndir}"
    }

    echo "Backing up current kernel to ${oldkerndir} ..."
    mkdir -p ${oldkerndir}
    chflags noschg ${kerndir}/kernel
    objcopy --strip-debug ${kerndir}/kernel ${oldkerndir}/kernel
    for f in ${kerndir}/*.ko; do
        objcopy --strip-debug ${f} ${oldkerndir}/${f##*/}
    done

    [ -f "${kerndir}/initrd.img" ] &&
        cp -p ${kerndir}/initrd.img ${oldkerndir}
    [ -f "${kerndir}/initrd.img.gz" ] &&
        cp -p ${kerndir}/initrd.img.gz ${oldkerndir}
    echo "DONE"
}

# Backup the old world
#
# backup_world(backfile)
#
backup_world() {
    local backfile="$1"
    local backdir=$(dirname "${backfile}")
    [ -d "${backdir}" ] || mkdir ${backdir}
    [ -f "${backfile}" ] && {
        rm -f "${backfile}"
        warn "Removed previously backed world: ${backfile}"
    }

    echo "Backing up current world to ${backfile} ..."
    tar -czf "${backfile}" \
        --options gzip:compression-level=1 \
        -C / \
        etc bin sbin lib libexec \
        usr/bin usr/sbin usr/lib usr/libexec &&
            echo "DONE" ||
            exit ${EC_TAR}
}

# Install the new system (kernel and world, excluding /etc)
install_system() {
    local file item path cpignore
    echo "Installing the new kernel and world ..."

    echo "  => Creating distribution directories ..."
    for item in \
            root:/ \
            var:/var \
            usr:/usr \
            include:/usr/include; do
        file=BSD.${item%:*}.dist
        path=${item#*:}
        echo "   * mtree: ${path} ..."
        mtree -deUq -f ${MNT_DIR}/etc.hdd/mtree/${file} -p ${path} ||
            exit ${EC_MTREE}
    done

    echo "  => Collecting files to be ignored ..."
    cpignore=$(mktemp -t ${NAME}) || exit ${EC_TMPFILE}
    for file in ${FILES_IGNORE}; do
        # NOTE: 'cpdup -X' doesn't normalize multiple '/' to be one.
        echo "${MNT_DIR%/}/${file#/}" >> ${cpignore}
        echo "   * ${file}  <ignored>"
    done

    echo "  => Installing kernel and world ..."
    for item in ${INSTALL_LIST}; do
        echo -n "   * Installing: ${item} ... "
        # NOTE: 'cpdup -X' doesn't normalize multiple '/' to be one.
        ${CPDUP} -o -X ${cpignore} ${MNT_DIR%/}/${item#/} /${item} ||
            exit ${EC_CPDUP}
        echo "ok"
    done

    rm -f ${cpignore}
    echo "  => DONE!"
}

# Add new users and groups
add_users() {
    local fpasswd="${MNT_DIR}/etc.hdd/master.passwd"
    local fgroup="${MNT_DIR}/etc.hdd/group"
    local _name _pw _uid _gid _gids item
    local _class _change _expire _gecos _home _shell _members
    echo "Adding new users and groups ..."

    echo "  => Adding new users ..."
    _gids=""
    grep -Ev '^(#.*|\s*)$' ${fpasswd} |
            while IFS=':' read -r _name _pw _uid _gid _class \
                                  _change _expire _gecos _home _shell; do
        pw usershow ${_name} -q >/dev/null && continue

        # NOTE: There is circular dependence: 'groupadd' requires the members
        #       already exist, while 'useradd' requires the group exists.
        #       So first assign new users to the 'nogroup' group, and make
        #       adjustments after group creation.
        echo "   * ${_name}, ${_uid}, ${_gid}, ${_gecos}, ${_home}, ${_shell}"
        pw useradd ${_name} \
            -u ${_uid} -g nogroup -d ${_home} -s ${_shell} \
            -L "${_class}" -c "${_gecos}" || exit ${EC_PW}
        _gids="${_gids} ${_name}:${_gid}"
    done

    echo "  => Adding new groups ..."
    grep -Ev '^(#.*|\s*)$' ${fgroup} |
            while IFS=':' read -r _name _pw _gid _members; do
        pw groupshow ${_name} -q >/dev/null && continue

        echo "   * ${_name}, ${_gid}, ${_members}"
        pw groupadd ${_name} -g ${_gid} -M "${_members}" || exit ${EC_PW}
    done

    echo "  => Adjusting the group of new users ..."
    for item in ${_gids}; do
        _name=${item%:*}
        _gid=${item#*:}
        echo "   * ${_name}, ${_gid}"
        pw usermod ${_name} -g ${_gid} || exit ${EC_PW}
    done
}

# Upgrade the system with new configuration files
upgrade_system() {
    local etcdir="${CACHE_DIR}/etc.new"
    local file file_etc file_new
    [ -d "${CACHE_DIR}" ] || mkdir "${CACHE_DIR}"
    echo "Upgrading system ..."
    echo "  => Coping new /etc to: ${etcdir}"
    ${CPDUP} -o ${MNT_DIR}/etc.hdd ${etcdir} || exit ${EC_CPDUP}

    echo "  => Removing ignored files ..."
    for file_etc in ${FILES_IGNORE}; do
        file_new="${etcdir}/${file_etc#/etc/}"
        if [ -f "${file_new}" ]; then
            rm -f "${file_new}"
            echo "   * ${file_new}  <ignored>"
        fi
    done

    echo "  => Identifying new/updated config files ..."
    (cd "${etcdir}" && find -s . -type f) | while read -r file; do
        file_etc="/etc/${file#./}"
        file_new="${etcdir}/${file#./}"
        if [ -f "${file_etc}" ]; then
            if cmp -s "${file_etc}" "${file_new}"; then
                rm -f "${file_new}"
            else
                mv "${file_new}" "${file_new}.${NEW_SUF}"
                echo "   * ${file_new}  [UPDATED]"
            fi
        else
            echo "   * ${file_new}  [NEW]"
        fi
    done

    echo "  => Installing new configurations ..."
    ${CPDUP} -o ${etcdir} /etc || exit ${EC_CPDUP}
    echo "  => DONE!"
    rm -rf "${etcdir}"
    echo "+---------+"
    echo "| WARNING | Files with '${NEW_SUF}' suffix need manual merge!"
    echo "+---------+"
}

# Clean up obsolete and deprecated files
cleanup() {
    local mk_upgrade tmpfile item itemcat

    mk_upgrade=/etc/upgrade/Makefile_upgrade.inc
    [ -e "${mk_upgrade}.${NEW_SUF}" ] && mk_upgrade=${mk_upgrade}.${NEW_SUF}
    echo "Removing obsolete and deprecated files ..."
    echo "(according to ${mk_upgrade})"
    tmpfile=$(mktemp -t ${NAME}) || exit ${EC_TMPFILE}
    make -f ${mk_upgrade} -V TO_REMOVE      | tr ' ' '\n' >  ${tmpfile}
    make -f ${mk_upgrade} -V TO_REMOVE_LATE | tr ' ' '\n' >> ${tmpfile}

    # Credit: https://stackoverflow.com/a/10929511
    # [ -n "${item}" ]: do not ignore the last line if not end with a '\n'
    while IFS='' read -r item || [ -n "${item}" ]; do
        if [ -n "${item}" ] && [ -e ${item} -o -L ${item} ]; then
            echo "  * ${item}"
            chflags -Rf noschg ${item}
            rm -rf ${item}
        fi
        if echo "${item}" | grep -q '/man/man[1-9]/'; then
            itemcat=$(echo "${item}" | sed 's|/man/man|/man/cat|')
            if [ -e "${itemcat}" ]; then
                echo "  * ${itemcat}"
                chflags -Rf noschg ${itemcat}
                rm -rf ${itemcat}
            fi
        fi
    done < ${tmpfile}
    rm -f ${tmpfile}
    echo "DONE"
}

# Misc operations after upgrade
postupgrade() {
    echo "Rebuild capability database ..."
    cap_mkdb /etc/login.conf
    echo "Rebuild password database ..."
    pwd_mkdb -p /etc/master.passwd
    echo "Rebuild mail aliases db ..."
    newaliases
    echo "Rebuild whatis database ..."
    makewhatis
    echo "Rebuild shared library cache ..."
    ldconfig -R

    echo "+=========================================================+"
    echo "The following config files need manual merge:"
    echo "+---------------------------------------------------------+"
    find -s /etc -name "*.${NEW_SUF}" | sort

    cat << _EOF_
+---------------------------------------------------------+
After manually merge the above files, reboot into the new
system, and upgrade the packages with:
    # pkg upgrade [-f]
+=========================================================+
_EOF_
}


#
# Sub-command functions
#

cmd_usage() {
    cat <<_EOF_
dfly-update - DragonFly BSD update tool using binary release/snapshots

Usage: ${0##*/} <sub-command>

Sub-commands:
    help | --help | -h
        Show this help.
    mount <dfly.img>
        Mount the given image file
    backup
        Back up the current kernel and world
    upgrade
        Install the new kernel, world, and config files
    cleanup
        Clean up obsolete files, umount and remove image file
    fly <dfly.img>
        Synthetic command to upgrade the system!

v${VERSION}
Aaron LI <aly@aaronly.me>
https://github.com/liweitianux/dfly-update
_EOF_
}

# Mount the given image file
cmd_mount() {
    [ $# -eq 1 ] ||
        error ${EC_ARGS} "cmd_mount: invalid arguments: $@"

    local file="$1"
    [ -f "${file}" ] ||
        error ${EC_NOFILE} "cmd_mount: file not exists: ${file}"
    mount_image "${file}" "${MNT_DIR}"
}

# Back up the current kernel and world
cmd_backup() {
    [ $# -eq 0 ] ||
        error ${EC_ARGS} "cmd_backup: invalid arguments: $@"

    backup_kernel
    backfile="${BACK_DIR}/world.tar.gz"
    backup_world "${backfile}"
}

# Install the new kernel, world, and config files.
cmd_upgrade() {
    [ $# -eq 0 ] ||
        error ${EC_ARGS} "cmd_upgrade: invalid arguments: $@"

    install_system
    add_users
    upgrade_system
}

# Clean up obsolete files, umount and remove image
cmd_cleanup() {
    [ $# -eq 0 ] ||
        error ${EC_ARGS} "cmd_cleanup: invalid arguments: $@"

    cleanup
    umount_image ${MNT_DIR}
    postupgrade
}

# Integrate all the upgrading steps -> fly :-)
cmd_fly() {
    [ $# -eq 1 ] ||
        error ${EC_ARGS} "cmd_fly: invalid arguments: $@"

    cmd_mount "$1"
    cmd_backup
    cmd_upgrade
    cmd_cleanup
}

#
# Main
#

# Load configurations
[ -r "${CONFIGFILE}" ] && . ${CONFIGFILE}

case $1 in
    mount)
        shift
        cmd_mount "$@"
        ;;
    backup)
        shift
        cmd_backup
        ;;
    upgrade)
        shift
        cmd_upgrade
        ;;
    cleanup)
        shift
        cmd_cleanup
        ;;
    fly)
        shift
        cmd_fly "$@"
        ;;
    help|--help|-h|*)
        cmd_usage
        ;;
esac

exit 0