#!/usr/bin/env bash
# -*- coding: utf-8 -*-
# region header
# Copyright Torben Sickert (info["~at~"]torben.website) 29.10.2015
#           Janosch Dobler (info["~at~"]jandob.com) 29.10.2015


# License
# -------
# This library written by Torben Sickert and Janosch Dobler stand under a
# creative commons naming 3.0 unported license.
# see http://creativecommons.org/licenses/by/3.0/deed.de
# This tool provides a generic way to install systemd based remote linux
# initramfs.

# Examples
# --------

# Start install progress command (Assuming internet is available):
# >>> ./build-initramfs.sh

# Note that you only get very necessary output until you provide "--verbose" as
# commandline options.
declare -rg _root_dir="$(readlink -f $(dirname ${BASH_SOURCE[0]}))"
declare -rg _repo_dir="${_root_dir}/systemd-init.git"
declare -rg _git_source="git://git.openslx.org/openslx-ng/systemd-init.git"
declare -rg _git_branch="master"
## region ensure presence of needed dependencies
set -o errexit
if [ ! -e "$_repo_dir" ]; then
    echo "Missing dracut modules repository, loading them."
    if ! hash git; then
        echo "Needed dependency \"git\" isn't available."
        echo "Please install \"git\" or provide the main repository in \"${_repo_dir}\"."
    fi
    git clone --branch "$_git_branch" --single-branch --depth 1 \
       "$_git_source" "${_repo_dir}"
    pushd "${_repo_dir}"
    git submodule init
    # try to clone submodules as shallowy as possible, since we cannot just
    # use '--depth 1' on submodules residing on non-master branches...
    for mod in $(grep -Po '(?<=^\[submodule ")([^"]+)' .gitmodules); do
        url="$(git config -f .gitmodules --get submodule.${mod}.url)"
        path="$(git config -f .gitmodules --get submodule.${mod}.path)"
        branch="$(git config -f .gitmodules --get submodule.${mod}.branch)"
        commit="$(git submodule status $path | grep -oE '[0-9a-f]{40}')"
        depth_arg=("--shallow-since")
        [ "$mod" = "dnbd3" ]                   && depth_arg+=("2019-02-12")
        [ "$mod" = "rebash" ]                  && depth_arg+=("2016-11-30")
        [ "$mod" = "qemu-xmount" ]             && depth_arg+=("2016-01-01")
        [ "$mod" = "xmount" ]                  && depth_arg+=("2015-11-05")
        [ "$mod" = "kernel-qcow2-linux" ]      && depth_arg+=("2019-08-25")
        [ "$mod" = "kernel-qcow2-util-linux" ] && depth_arg+=("2019-08-15")
        git clone -n --no-tags "${depth_arg[@]}" --branch "$branch" "$url" "$path"
        pushd "$path"
        git checkout "$commit"
        popd
    done
    # apply patches for submodules
    git submodule foreach '
        for p in $(find ${toplevel}/builder/patches/${path##*/} -type f -name "*.patch" | sort -n); do
            patch -p1 < $p || echo "Failed to patch $path with $p - expect errors."
        done 2>/dev/null
    '
    popd
    ln -s "${_repo_dir}/builder/modules.d" "${_root_dir}/modules.d"
fi
set +o errexit
## endregion
# shellcheck source=./dnbd3-rootfs/scripts/rebash/core.sh
source "${_root_dir}/modules.d/dnbd3-rootfs/scripts/rebash/core.sh"
core.import exceptions
core.import logging
core.import utils
core.import change_root
# endregion
# region properties
# shellcheck disable=SC2034
build_initramfs__doc_test_setup__='exceptions.activate'
file_path='/boot/initramfs.img'
dracut_parameter=(--force --no-hostonly)
verbose='no'
debug='no'
target=''
cleanup='no'
full_cleanup='no'
use_systemd_in_initramfs='no'
# shellcheck disable=SC2034
declare -A core_dependencies=(
    [cat]='print messages' \
    [cpio]='pack initramfs' \
    ['dhclient arping']='support network connection in resulting initramfs' \
    [dirname]='core logic' \
    [dmsetup]='create a (temporary) writable layer during boot' \
    [grep]='retrieve right boot partition during boot' \
    [mktemp]='create save temporary files and dictionaries' \
    [pkg-config]='retrieve information of installed development packages' \
    [tee]='read from standard input and write to standard output and files' \
    [readlink]="connect dracut module with dracut's module system" \
    [rm]='remove (temporary) files' \
    [shift]='parse command line' \
    [sed]='process strings' \
    ['cmake gcc make']='dynamically compile needed resources against current or given kernel')
# shellcheck disable=SC2034
declare -A optional_dependencies=(
    [chroot]='build against a distribution other than this program runs in' \
    ['curl git gzip tar']='dynamically retrieve and unpack missing application which will be compiled for current or given kernel' \
    ['mkfs.ext4 fsck']='support for persistent binary diffs in image files')
# shellcheck disable=SC2034
declare -A core_shared_library_pattern_dependencies=(
    [libz]='compile dnbd3 for given or current kernel')
# shellcheck disable=SC2034
declare -A optional_shared_library_pattern_dependencies=()
# shellcheck disable=SC2034
declare -A core_package_dependencies=()
# shellcheck disable=SC2034
declare -A optional_package_dependencies=(
    ['glib-2.0 pixman-1']='support template systems in container (usually used by virtual runtime environments)')
# endregion
# region functions
## region command line interface
print_usage_message() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Prints a description about how to use this program.

    >>> print_usage_message &>/dev/null
    '
    logging.cat << EOF
This program provides a generic way to install systemd based remote linux
initramfs.
EOF
}
print_usage_examples() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Prints a description about how to use this program by providing examples.

    >>> print_usage_examples &>/dev/null
    '
    logging.cat << EOF
Start install progress:
>>> ./build_initramfs.sh
EOF
}
print_command_line_option_description() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Prints descriptions about each available command line option.

    >>> print_command_line_option_description &>/dev/null
    '
    logging.cat << EOF
-h --help Shows this help message.

-v --verbose Tells you what is going on (default: "$verbose").

-d --debug Gives you any output from all tools which are used
    (default: "$debug").

-p --file-path Target location for initramfs file
    (default: "$file_path").

-c --cleanup Removes all distribution specific compiled files.

-f --full-cleanup Removes all retrieved and compiled files (usefull to retrieve latest version of all nested modules).

-t --target Creates an image against given target template filesystem. If not
    explicitly specified current system will be used as template system
    (default: "$target").

-i --init Initializes the various repositories and build the required
    dependencies but do not build the initramfs. Use this to accelerate
    subsequent calls of this script.

-k --kernel-version Creates an image for the given kernel version. Will
    require the presence of kernel headers for this version.
    (default: "$(uname -r)")

-s --use-systemd-in-initramfs Use Systemd as init process in initramfs
    (improved performance but less features)
    (default: "$use_systemd_in_initramfs").

Additional dracut parameter and normal parameter can be added by delimiting
them via a single dash (-) (default: "$dracut_parameter" with
"--modules" and dynamically determined modules. Additional custom modules are
concatenated.).
EOF
}
print_help_message() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Provides a help message for this module.

    >>> print_help_message &>/dev/null
    '
    logging.plain "\nUsage: $0 [options]\n"
    print_usage_message "$@"
    logging.plain '\nExamples:\n'
    print_usage_examples "$@"
    logging.plain -e '\nOption descriptions:\n'
    print_command_line_option_description "$@"
    logging.plain
}
parse_command_line() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Provides the command line interface and interactive questions.

    >>> parse_command_line -h &>/dev/null

    >>> echo "$verbose"
    no
    >>> logging.get_level
    critical
    >>> parse_command_line -v
    >>> echo "$verbose"
    >>> logging.get_level
    yes
    info

    >>> echo "$debug"
    no
    >>> parse_command_line --debug
    >>> echo "$debug"
    >>> logging.get_level
    yes
    debug

    >>> parse_command_line -p
    +doc_test_capture_stderr
    +doc_test_contains
    +doc_test_ellipsis
    Error with given option "-p":
    Traceback (most recent call first):
    ...

    >>> echo "$file_path"
    /boot/initramfs.img
    >>> parse_command_line -p /tmp/test.img
    >>> echo "$file_path"
    /tmp/test.img

    >>> echo "$cleanup"
    no
    >>> parse_command_line --cleanup
    >>> echo "$cleanup"
    yes

    >>> echo "$full_cleanup"
    no
    >>> parse_command_line --full-cleanup
    >>> echo "$full_cleanup"
    yes

    >>> echo "$full_cleanup"
    no
    >>> parse_command_line --full-cleanup
    >>> echo "$full_cleanup"
    yes

    >>> echo "$use_systemd_in_initramfs"
    no
    >>> parse_command_line -s
    >>> echo "$use_systemd_in_initramfs"
    yes

    >>> parse_command_line -t; echo $?
    +doc_test_capture_stderr
    +doc_test_contains
    +doc_test_ellipsis
    Error with given option "-t":
    Traceback (most recent call first):
    ...

    >>> [[ "$target" = "" ]]
    >>> parse_command_line -t /tmp/
    >>> echo "$target"
    /tmp/

    >>> echo "${dracut_parameter[@]}"
    --force --no-hostonly
    >>> parse_command_line - --test
    >>> echo "${dracut_parameter[@]}"
    --force --no-hostonly --test

    >>> parse_command_line - --install "vim htop"
    >>> echo "${dracut_parameter[3]}"
    vim htop

    >>> parse_command_line --no-available-option; echo $?
    +doc_test_capture_stderr
    +doc_test_contains
    +doc_test_ellipsis
    Error with given option "--no-available-option":
    Traceback (most recent call first):
    ...
    '
    while true; do
        case "$1" in
            -h|--help)
                shift
                print_help_message "$0"
                exit 0
                ;;
            -v|--verbose)
                shift
                verbose='yes'
                ;;
            -d|--debug)
                shift
                debug='yes'
                ;;
            -p|--file-path)
                local given_argument="$1"
                shift
                file_path="$1"
                if [[ "$file_path" == '' ]]; then
                    logging.critical \
                        "Error with given option \"$given_argument\": This option needs a path to save initramfs image to."
                    return 1
                fi
                shift
                ;;
            -c|--cleanup)
                shift
                cleanup='yes'
                ;;
            -f|--full-cleanup)
                shift
                full_cleanup='yes'
                ;;
            -s|--use-systemd-in-initramfs)
                shift
                use_systemd_in_initramfs='yes'
                ;;
            -t|--target)
                local given_argument="$1"
                shift
                target="$1"
                if [[ "$target" == '' ]]; then
                    logging.critical \
                        "Error with given option \"$given_argument\": This option needs a path create initramfs from."
                    return 1
                fi
                shift
                ;;
            -i|--init)
                shift
                initialize='yes'
                ;;
            -k|--kernel-version)
                local given_argument="$1"
                shift
                kernel_version="$1"
                if [ -z "$kernel_version" ]; then
                    logging.critical \
                        "Error with given option \"$given_argument\": This option needs a kernel version to build the initramfs for."
                    return 1
                fi
                shift
                ;;
            -H|--kernel-headers)
                local given_argument="$1"
                shift
                kernel_headers="$1"
                if [ -z "$kernel_headers" ]; then
                    logging.critical \
                        "Error with given option \"$given_argument\": This option needs the path to the kernel headers."
                    return 1
                fi
                shift
                ;;
            -q|--qcow-handler)
                local given_argument="$1"
                shift
                qcow_handler="$1"
                if [ -z "$qcow_handler" ]; then
                    logging.critical \
                        "Error with given option \"$given_argument\": This options needs to be either 'xmount' or 'kernel'."
                    return 1
                fi
                shift
                ;;
            -u|--update)
                shift
                update='yes'
                ;;
            -)
                shift
                while [[ "$1" =~ ^.+$ ]]; do
                    dracut_parameter+=("$1")
                    shift
                done
                ;;
            '')
                break
                ;;
            *)
                logging.critical \
                    "Error with given option \"$1\": This argument is not available."
                return 1
        esac
    done
    if [ "$verbose" == 'yes' ]; then
        logging.set_level info
    fi
    if [ "$debug" == 'yes' ]; then
        logging.set_level debug
    fi
    # NOTE: Remove the following line if this sanity check should be performed.
    return 0
    if [[ "$UID" != '0' ]]; then
        logging.critical \
            "You have to run this script as \"root\" not as \"${USER}\"."
        exit 2
    fi
    return 0
}
## endregion
## region helper
dependency_check() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Check for given dependencies with given dependency checker and log
    corresponding messages.

    Example:

    `dependency_check core dependencies utils_dependency_check program`
    '
    local result=0

    # shellcheck disable=SC2016,SC1004
    eval 'for dependency_group in "${!'"$1"'_'"$2"'[@]}"; do
        # NOTE: If "dependency_check_result" would be marked as local it is
        # empty later.
        dependency_check_result="$($3 $dependency_group)" || \
            local return_code=$?
        if [[ $return_code == 1 ]]; then
            echo "$dependency_check_result"
            return $return_code
        elif [[ $return_code == 2 ]]; then
            while read dependency; do
                eval "local reason=\${${1}_${2}[\"\$dependency_group\"]}"
                local message="Missing $1 $4 dependency \"$dependency\" needed to $reason."
                if [[ $1 == core ]]; then
                    logging.critical "$message"
                else
                    logging.warn "$message"
                fi
            done <<< $dependency_check_result
            result=2
        fi
        return_code=0
    done'
    return $result
}
initialize_dracut() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Downloads and compiles dracut.

    Example:

    `initialize_dracut`
    '
    # First check what version to get
    # Autodetect the kmod version present on the system to decide which dracut version to get
    #  * v47 requires kmod >= 23 (Available in Ubuntu 18.04)
    #  * v46 works with kmod == 20 (CentOS 7.5 only provides kmod v20)
    if [ "$(pkg-config --modversion libkmod)" -ge 23 ]; then
        dracut_version="047"
    else
        dracut_version="046"
    fi
    dracut_resource_url="https://www.kernel.org/pub/linux/utils/boot/dracut/dracut-$dracut_version.tar.gz"
    if [[ ! -f "${_root_dir}/dracut/install/dracut-install" ]]; then
        mkdir --parents "${_root_dir}/dracut"
        logging.info "Download and extract dracut version $dracut_version"
        curl --location "$dracut_resource_url" | tar --extract --gzip \
             --directory "${_root_dir}/dracut" --strip-components 1
        pushd "${_root_dir}/dracut"
        # NOTE: On virtualbox shared folder symlinks are not allowed.
        # NOTE: make the dracut-install binary (dracut-install resolves
        # dependencies etc.)
        logging.info 'Compiling dracut.'
        ./configure
        make install/dracut-install
        # NOTE: We have to copy the binary to current instead of symlinking
        # them since this feature isn't supported in shared virtual box machine
        # folders.
        # If symlinks would be available we could simply use:
        # >>> make dracut-install
        popd
    fi
    cp "${_root_dir}/dracut/install/dracut-install" \
        "${_root_dir}/dracut/dracut-install"
    return $?
}

cleanup() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Removes distribution specific generated files.

    Example:

    `cleanup`
    '
    local plugin_path
    plugin_path="${_root_dir}/modules.d/dnbd3-rootfs"
    # shellcheck disable=SC1090
    source "${plugin_path}/module-setup.sh"
    # shellcheck disable=SC2034
    moddir="$(cd "$plugin_path" &>/dev/null && pwd)"
    clean
    return $?
}
## endregion
# endregion
# region controller
main() {
    # shellcheck disable=SC2016,SC2034
    local __doc__='
    Main Entry point for the build initramfs logic. Triggers command line
    parsing and calls sub routines depending on given command line arguments.

    Example:

    `main`
    '
    exceptions.activate
    # region dependency checks and command line parsing
    result=0
    dependency_check core dependencies utils_dependency_check program || \
        result=$?
    dependency_check core shared_library_pattern_dependencies \
        utils_dependency_check_shared_library 'shared library' || result=$?
    dependency_check core package_dependencies utils_dependency_check_pkgconfig \
        package || result=$?
    [[ $result == 0 ]] || exit $result

    logging.set_commands_level debug
    logging.set_level critical

    if ! parse_command_line "$@"; then
        print_help_message "$0"
        exit 1
    fi

    dependency_check optional dependencies utils_dependency_check program || \
        result=$?
    dependency_check optional shared_library_pattern_dependencies \
        utils_dependency_check_shared_library 'shared library' || result=$?
    dependency_check optional package_dependencies \
        utils_dependency_check_pkgconfig package || result=$?
    [[ $result == 1 ]] && exit $result
    # endregion

    # region sanity check kernel version and qcow handler
    # if no kernel was specified as dracut argument, use the running kernel's version
    logging.info "Building for:"
    if [ -z "$kernel_version" ]; then
       kernel_version="$(uname -r)"
    fi
    logging.info " * kernel version: $kernel_version"
    # similar for kernel headers needed to compile dnbd3 against.
    if [ -z "$kernel_headers" ]; then
       kernel_headers="/lib/modules/${kernel_version}/build"
    fi
    if [ ! -f "${kernel_headers}/Makefile" ]; then
       logging.critical 'Missing core dependency "linux-headers" for version to compile against given or current kernel.'
    fi
    logging.info " * kernel headers: $kernel_headers"
    [ -n "$qcow_handler" ] && logging.info " * qcow2 handler: $qcow_handler"
    # endregion

    # region handle delegated operations to specified target
    if [[ "$target" != '' ]]; then
        _target="$target"
        if [[ -f "$target" ]]; then
            _target="$(mktemp --directory)"
            _xmount_mountpoint_target="$(mktemp --directory)"
            xmount --in qemu "$target" --out raw "$_xmount_mountpoint_target"
            _xmount_device_target="$(losetup --find)"
            losetup --partscan "$_xmount_device_target" \
                "${_xmount_mountpoint_target}/"*.dd
            # TODO Use partscan
            mount "$_xmount_device_target" "$_target"
        fi
        if [[ -d "$_target" ]]; then
            _temporary_working_directory="$(chroot "$_target" mktemp --directory)"
            mount --bind "$(pwd)" "${_target}${_temporary_working_directory}"
            _parameter_skip=false
            _parameter_to_forward=()
            for _parameter; do
                if $_parameter_skip; then
                    _parameter_skip=false
                elif [[ "$_parameter" == '-t' ]] || \
                     [[ "$_parameter" == '--target' ]]; then
                    _parameter_skip=true
                else
                    _parameter_to_forward+=("$_parameter")
                fi
            done
            # NOTE: We would have to temporary patch dracut to avoid removing the
            # environment variables "LD_LIBRARY_PATH" and "LD_PRELOAD" to get
            # "fakechroot" working with dracut. So we should remove this variables
            # before running the patched dracut version to follow the initial
            # intention. You should first do:
            # >>> unset LD_LIBRARY_PATH
            # >>> unset LD_PRELOAD
            # and patch "dracut.sh" temporary to comment out:
            # >>> unset LD_LIBRARY_PATH
            # >>> unset LD_PRELOAD
            # To avoid to broke the "fakechroot" environment pipe the ldconfig call
            # to the native one:
            # >>> FAKECHROOT_CMD_SUBST=/usr/bin/ldconfig=/usr/bin/ldconfig
            # shellcheck disable=SC2086
            change_root "${_target}" \
                "${_temporary_working_directory}/${BASH_SOURCE[0]}" \
                ${_parameter_to_forward[*]}
            mv "${_target}/$file_path" "$file_path"
            # Do cleanup procedures.
            umount "${_target}${_temporary_working_directory}"
            rm --recursive --force "${_target}${_temporary_working_directory}"
            if [[ -f "$target" ]]; then
                umount "$_target"
                losetup --detach "$_xmount_device_target"
                umount "$_xmount_mountpoint_target"
                rm --recursive --force "$_target" "$_xmount_mountpoint_target"
            fi
        fi
        exit 0
    fi
    # endregion
    # region handle '--update' to update all the modules in 'modules.d'
    if [ "$update" == "yes" ]; then
        pushd "${_repo_dir}"
        git pull
        popd
    fi
    # endregion
    # region handle dependencies which can be resolved automatically
    logging.info 'Checking dracut.'
    if [[ ! -f "${_root_dir}/dracut/dracut-install" ]]; then
        logging.info "Dracut isn't available yet loading it."
        initialize_dracut
    fi

    for _dracut_module in "${_root_dir}/modules.d/"*; do
        [ -d "${_dracut_module}" ] || continue
        _dracut_module="$(basename $_dracut_module)"
        # shouldn't we use absolute paths here?
        _dracut_module_relative_path="../../modules.d/${_dracut_module}"
        # TODO change to *not* always use '90' ...
        _dracut_module_target="${_root_dir}/dracut/modules.d/00${_dracut_module}"
        if [[ ! -L "$_dracut_module_target" || "$(readlink \
            "$_dracut_module_target")" != "$_dracut_module_relative_path" ]]; then
            logging.info \
                "Link ${_dracut_module} plugin into dracut modules folder ($_dracut_module_relative_path -> $_dracut_module_target)."
            if ! ln --symbolic --force "$_dracut_module_relative_path" \
            "$_dracut_module_target"; then
                logging.warn \
                    "Linking \"$_dracut_module_relative_path\" to \"$_dracut_module_target\" failed." \
                    " We will copy them. So we have to recopy it every time to ensure that recompiled things take effect."
                cp --recursive --force --no-target-directory \
                    "${_root_dir}/modules.d/$_dracut_module" \
                    "$_dracut_module_target"
            fi
        fi
    done
    # endregion

    # region prepare modules and perform final dracut call
    _loglevel=''
    if [ "$verbose" == 'yes' ]; then
        _loglevel='--verbose'
    fi
    _modules='dnbd3-rootfs conf-tgz'
    logging.info "Default modules: ${_modules}"
    if [ "$debug" == 'yes' ]; then
        _loglevel="$_loglevel --stdlog 4"
        _modules="$_modules i18n terminfo"
    fi
    if [ "$use_systemd_in_initramfs" == 'yes' ]; then
        _modules="$_modules systemd systemd-initrd dracut-systemd"
    fi
    # Preprocess done - start build, cleanup or full cleanup
    if [[ "$full_cleanup" == 'yes' ]]; then
        logging.info 'Removing all modules.'
        rm "${_root_dir}/modules.d" \
            "${_root_dir}/dracut" --recursive --force
    elif [[ "$cleanup" == 'yes' ]]; then
        logging.info 'Removing distribution specific files.'
        cleanup
    elif [[ "$initialize" == 'yes' ]]; then
        . "${_root_dir}/modules.d/dnbd3-rootfs/helper/build.inc"
        build_initialize_components
    else
        logging.info 'Build initramfs.'
        # NOTE: We deactivate our exception handle since dracut returns "1" if
        # it is launched with help parameter ("-h" or "--help").
        exceptions.deactivate
        # NOTE: We temporary allow dracut to forward all messages since we
        # forward all logging configurations.
        _commands_log_level_backup="$(logging.get_commands_level)"
        _log_level_backup="$(logging.get_level)"
        logging.set_level debug
        logging.set_commands_level debug
        # shellcheck disable=SC2086
        "${_root_dir}/dracut/dracut.sh" --local \
            $_loglevel --modules "$_modules" --conf /etc/dracut.conf \
            --confdir /etc/dracut.conf.d "${dracut_parameter[@]}" \
            --kver "${kernel_version}" "$file_path"
        _return_code=$?
        logging.set_commands_level "$_commands_log_level_backup"
        logging.set_level "$_log_level_backup"
        if [[ "$_return_code" != 0 ]]; then
            logging.error 'Building initial ram file system failed.'
            exit 1
        fi
        exceptions.activate
        # NOTE: dracut generate the initramfs with 0600 permissions
        chmod 0644 "${file_path}"
    fi
    # endregion
    exceptions.deactivate
}
# endregion
if core.is_main; then
    main "$@"
fi
# region vim modline
# vim: set tabstop=4 shiftwidth=4 expandtab:
# vim: foldmethod=marker foldmarker=region,endregion:
# endregion