#!/bin/bash
#
# grubby wrapper to manage BootLoaderSpec files
#
#
# Copyright 2018 Red Hat, Inc.  All rights reserved.
#
# 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 2 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 <http://www.gnu.org/licenses/>.

readonly SCRIPTNAME="${0##*/}"

CMDLINE_LINUX_DEBUG=" systemd.log_level=debug systemd.log_target=kmsg"
LINUX_DEBUG_VERSION_POSTFIX="_with_debugging"
LINUX_DEBUG_TITLE_POSTFIX=" with debugging"

declare -a bls_file
declare -a bls_title
declare -a bls_version
declare -a bls_linux
declare -a bls_initrd
declare -a bls_options
declare -a bls_id

[[ -f /etc/sysconfig/kernel ]] && . /etc/sysconfig/kernel
[[ -f /etc/os-release ]] && . /etc/os-release
read MACHINE_ID < /etc/machine-id
arch=$(uname -m)

if [[ $arch = 's390' || $arch = 's390x' ]]; then
    bootloader="zipl"
else
    bootloader="grub2"
fi

print_error() {
    echo "$1" >&2
    exit 1
}

if [[ ${#} = 0 ]]; then
    print_error "no action specified"
fi

get_bls_value() {
    local bls="$1" && shift
    local key="$1" && shift

    echo "$(grep "^${key}[ \t]" "${bls}" | sed -e "s,^${key}[ \t]*,,")"
}

set_bls_value() {
    local bls="$1" && shift
    local key="$1" && shift
    local value="$1" && shift

    sed -i -e "s,^${key}.*,${key} ${value}," "${bls}"
}

append_bls_value() {
    local bls="$1" && shift
    local key="$1" && shift
    local value="$1" && shift

    old_value="$(get_bls_value ${bls} ${key})"
    set_bls_value "${bls}" "${key}" "${old_value}${value}"
}

get_bls_values() {
    count=0
    for bls in $(ls -vr ${blsdir}/*.conf 2> /dev/null); do
        bls_file[$count]="${bls}"
        bls_title[$count]="$(get_bls_value ${bls} title)"
        bls_version[$count]="$(get_bls_value ${bls} version)"
        bls_linux[$count]="$(get_bls_value ${bls} linux)"
        bls_initrd[$count]="$(get_bls_value ${bls} initrd)"
        bls_options[$count]="$(get_bls_value ${bls} options)"
        bls_id[$count]="$(get_bls_value ${bls} id)"

        count=$((count+1))
    done
}

get_default_index() {
    local default=""
    local index="-1"
    local title=""
    local version=""
    if [[ $bootloader = "grub2" ]]; then
	default="$(grep '^saved_entry=' ${env} | sed -e 's/^saved_entry=//')"
    else
	default="$(grep '^default=' ${zipl_config} | sed -e 's/^default=//')"
    fi

    if [[ -z $default ]]; then
	index=0
    elif [[ $default =~ ^[0-9]+$ ]]; then
	index="$default"
    fi

    # GRUB2 and zipl use different fields to set the default entry
    if [[ $bootloader = "grub2" ]]; then
	title="$default"
    else
	version="$default"
    fi

    for i in ${!bls_file[@]}; do
        if [[ $title = ${bls_title[$i]} || $version = ${bls_version[$i]} ||
           $i -eq $index ]]; then
            echo $i
            return
        fi
    done
}

display_default_value() {
    case "$display_default" in
        kernel)
            echo "${bls_linux[$default_index]}"
            exit 0
            ;;
        index)
            echo "$default_index"
            exit 0
            ;;
        title)
            echo "${bls_title[$default_index]}"
            exit 0
            ;;
    esac
}

param_to_indexes() {
    local param="$1"
    local indexes=""

    if [[ $param = "ALL" ]]; then
        for i in ${!bls_file[@]}; do
            indexes="$indexes $i"
        done
        echo -n $indexes
        return
    fi

    if [[ $param = "DEFAULT" ]]; then
        echo -n $default_index
        return
    fi

    for i in ${!bls_file[@]}; do
        if [[ $param = "${bls_linux[$i]}" ]]; then
            indexes="$indexes $i"
        fi

        if [[ $param = "TITLE=${bls_title[$i]}" ]]; then
            indexes="$indexes $i"
        fi

	if [[ $param = $i ]]; then
	    indexes="$indexes $i"
	fi
    done

    if [[ -n $indexes ]]; then
        echo -n $indexes
        return
    fi

    echo -n "-1"
}

display_info_values() {
    local indexes=($(param_to_indexes "$1"))

    for i in ${indexes[*]}; do
        echo "index=$i"
        echo "kernel=${bls_linux[$i]}"
        echo "args=\"${bls_options[$i]}\""
        echo "initrd=${bls_initrd[$i]}"
        echo "title=${bls_title[$i]}"
    done
    exit 0
}

mkbls() {
    local kernel=$1 && shift
    local kernelver=$1 && shift
    local datetime=$1 && shift

    local debugname=""
    local flavor=""

    if [[ $kernelver == *\+* ]] ; then
        local flavor=-"${kernelver##*+}"
        if [[ $flavor == "-debug" ]]; then
            local debugname="with debugging"
	    local debugid="-debug"
        fi
    fi

    cat <<EOF
title ${NAME} (${kernelver}) ${VERSION}${debugname}
version ${kernelver}${debugid}
linux ${kernel}
initrd /initramfs-${kernelver}.img
options \$kernelopts
id ${ID}-${datetime}-${kernelver}${debugid}
grub_users \$grub_users
grub_arg --unrestricted
grub_class kernel${flavor}
EOF
}

remove_bls_fragment() {
    local indexes=($(param_to_indexes "$1"))

    if [[ $indexes = "-1" ]]; then
	print_error "The param $1 is incorrect"
    fi

    for i in ${indexes[*]}; do
        rm -f "${bls_file[$i]}"
    done

    get_bls_values
}

add_bls_fragment() {
    local kernel="$1" && shift
    local title="$1" && shift
    local options="$1" && shift
    local initrd="$1" && shift
    local extra_initrd="$1" && shift

    if [[ $kernel = *"vmlinuz-"* ]]; then
	kernelver="${kernel##*/vmlinuz-}"
    else
	kernelver="${kernel##*/}"
    fi

    if [[ ! -d "/lib/modules/${kernelver}" || ! -f "/boot/vmlinuz-${kernelver}" ]] &&
       [[ $bad_image != "true" ]]; then
        print_error "The ${kernelver} kernel isn't installed in the machine"
    fi

    if [[ -z $title ]]; then
	print_error "The kernel title must be specified"
    fi

    if [[ ! -d $blsdir ]]; then
        install -m 700 -d "${blsdir}"
    fi

    bls_target="${blsdir}/${MACHINE_ID}-${kernelver}.conf"
    kernel_dir="/lib/modules/${kernelver}"
    if [[ -f "${kernel_dir}/bls.conf" ]]; then
        cp -aT "${kernel_dir}/bls.conf" "${bls_target}" || exit $?
    else
	if [[ -d $kernel_dir ]]; then
	    datetime="$(date -u +%Y%m%d%H%M%S -d "$(stat -c '%y' "${kernel_dir}")")"
	else
	    datetime=0
	fi
        mkbls "${kernel}" "${kernelver}" "${datetime}" > "${bls_target}"
    fi

    if [[ -n $title ]]; then
        set_bls_value "${bls_target}" "title" "${title}"
    fi

    if [[ -n $options ]]; then
        set_bls_value "${bls_target}" "options" "${options}"
    fi

    if [[ -n $initrd ]]; then
        set_bls_value "${bls_target}" "initrd" "${initrd}"
    fi

    if [[ -n $extra_initrd ]]; then
        append_bls_value "${bls_target}" "initrd" "${extra_initrd}"
    fi

    if [[ $MAKEDEBUG = "yes" ]]; then
        arch="$(uname -m)"
        bls_debug="$(echo ${bls_target} | sed -e "s/\.${arch}/-debug.${arch}/")"
        cp -aT  "${bls_target}" "${bls_debug}"
        append_bls_value "${bls_debug}" "title" "${LINUX_DEBUG_TITLE_POSTFIX}"
        append_bls_value "${bls_debug}" "version" "${LINUX_DEBUG_VERSION_POSTFIX}"
        append_bls_value "${bls_debug}" "options" "${CMDLINE_LINUX_DEBUG}"
        blsid="$(get_bls_value ${bls_debug} "id" | sed -e "s/\.${arch}/-debug.${arch}/")"
        set_bls_value "${bls_debug}" "id" "${blsid}"
    fi

    get_bls_values

    if [[ $make_default = "true" ]]; then
        set_default_bls "TITLE=${title}"
    fi

    exit 0
}

update_args() {
    local args=$1 && shift
    local remove_args=($1) && shift
    local add_args=($1) && shift

    for arg in ${remove_args[*]}; do
        args="$(echo $args | sed -e "s,$arg[^ ]*,,")"
    done

    for arg in ${add_args[*]}; do
        if [[ $arg = *"="* ]]; then
            value=${arg##*=}
            key=${arg%%=$value}
            exist=$(echo $args | grep "${key}=")
            if [[ -n $exist ]]; then
                args="$(echo $args | sed -e "s,$key=[^ ]*,$key=$value,")"
            else
                args="$args $key=$value"
            fi
        else
            exist=$(echo $args | grep $arg)
            if ! [[ -n $exist ]]; then
                args="$args $arg"
            fi
        fi
    done

    echo ${args}
}

update_bls_fragment() {
    local indexes=($(param_to_indexes "$1")) && shift
    local remove_args=$1 && shift
    local add_args=$1 && shift
    local initrd=$1 && shift

    for i in ${indexes[*]}; do
	if [[ -n $remove_args || -n $add_args ]]; then
            local new_args="$(update_args "${bls_options[$i]}" "${remove_args}" "${add_args}")"
            set_bls_value "${bls_file[$i]}" "options" "${new_args}"
	fi

	if [[ -n $initrd ]]; then
	    set_bls_value "${bls_file[$i]}" "initrd" "${initrd}"
	fi
    done
}

set_default_bls() {
    local index=($(param_to_indexes "$1"))

    if [[ $bootloader = grub2 ]]; then
        grub2-editenv "${env}" set saved_entry="${bls_title[$index]}"
    else
        local default="${bls_version[$index]}"
        local current="$(grep '^default=' ${zipl_config} | sed -e 's/^default=//')"
        if [[ -n $current ]]; then
            sed -i -e "s,^default=.*,default=${default}," "${zipl_config}"
        else
            echo "default=${default}" >> "${zipl_config}"
        fi
    fi
}

remove_var_prefix() {
    if [[ -n $remove_kernel && $remove_kernel =~ ^/ ]]; then
       remove_kernel="/${remove_kernel##*/}"
    fi

    if [[ -n $initrd ]]; then
	initrd="/${initrd##*/}"
    fi

    if [[ -n $extra_initrd ]]; then
	extra_initrd=" /${extra_initrd##*/}"
    fi

    if [[ -n $kernel ]]; then
	kernel="/${kernel##*/}"
    fi

    if [[ -n $update_kernel && $update_kernel =~ ^/ ]]; then
	update_kernel="/${update_kernel##*/}"
    fi
}

print_usage()
{
    cat <<EOF
Usage: grubby [OPTION...]
      --add-kernel=kernel-path            add an entry for the specified kernel
      --args=args                         default arguments for the new kernel or new arguments for kernel being updated)
      --bad-image-okay                    don't sanity check images in boot entries (for testing only)
  -c, --config-file=path                  path to grub config file to update ("-" for stdin)
      --copy-default                      use the default boot entry as a template for the new entry being added; if the default is not a linux image, or if the kernel referenced by the default image does not exist, the
                                          first linux entry whose kernel does exist is used as the template
      --default-kernel                    display the path of the default kernel
      --default-index                     display the index of the default kernel
      --default-title                     display the title of the default kernel
      --env=path                          path for environment data
      --grub2                             configure grub2 bootloader
      --info=kernel-path                  display boot information for specified kernel
      --initrd=initrd-path                initrd image for the new kernel
  -i, --extra-initrd=initrd-path          auxiliary initrd image for things other than the new kernel
      --make-default                      make the newly added entry the default boot entry
  -o, --output-file=path                  path to output updated config file ("-" for stdout)
      --remove-args=STRING                remove kernel arguments
      --remove-kernel=kernel-path         remove all entries for the specified kernel
      --set-default=kernel-path           make the first entry referencing the specified kernel the default
      --set-default-index=entry-index     make the given entry index the default entry
      --title=entry-title                 title to use for the new kernel entry
      --update-kernel=kernel-path         updated information for the specified kernel
      --zipl                              configure zipl bootloader
  -b, --bls-directory                     path to directory containing the BootLoaderSpec fragment files

Help options:
  -?, --help                              Show this help message

EOF
}

OPTS="$(getopt -o c:i:o:b:? --long help,add-kernel:,args:,bad-image-okay,\
config-file:,copy-default,default-kernel,default-index,default-title,env:,\
grub2,info:,initrd:,extra-initrd:,make-default,output-file:,remove-args:,\
remove-kernel:,set-default:,set-default-index:,title:,update-kernel:,zipl,\
bls-directory:,add-kernel:,add-multiboot:,mbargs:,mounts:,boot-filesystem:,\
bootloader-probe,debug,devtree,devtreedir:,elilo,efi,extlinux,grub,lilo,\
output-file:,remove-mbargs:,remove-multiboot:,silo,yaboot -n ${SCRIPTNAME} -- "$@")"

[[ $? = 0 ]] || exit 1

eval set -- "$OPTS"

while [ ${#} -gt 0 ]; do
    case "$1" in
        --help|-h)
            print_usage
            exit 0
            ;;
        --add-kernel)
            kernel="${2}"
            shift
            ;;
        --args)
            args="${2}"
            shift
            ;;
        --bad-image-okay)
            bad_image=true
            ;;
        --config-file|-c)
            zipl_config="${2}"
            shift
            ;;
        --copy-default)
            copy_default=true
            ;;
        --default-kernel)
            display_default="kernel"
            ;;
        --default-index)
            display_default="index"
            ;;
        --default-title)
            display_default="title"
            ;;
        --env)
            env="${2}"
            shift
            ;;
        --grub2)
            bootloader="grub2"
            ;;
        --info)
            display_info="${2}"
            shift
            ;;
        --initrd)
            initrd="${2}"
            shift
            ;;
        --extra-initrd|-i)
            extra_initrd=" /${2}"
            shift
            ;;
        --make-default)
            make_default=true
            ;;
        --output-file|-o)
            output_file="${2}"
            shift
            ;;
        --remove-args)
            remove_args="${2}"
            shift
            ;;
        --remove-kernel)
            remove_kernel="${2}"
            shift
            ;;
        --set-default)
            set_default="${2}"
            shift
            ;;
        --set-default-index)
            set_default="${2}"
            shift
            ;;
        --title)
            title="${2}"
            shift
            ;;
        --update-kernel)
            update_kernel="${2}"
            shift
            ;;
        --zipl)
            bootloader="zipl"
            ;;
        --bls-directory|-b)
            blsdir="${2}"
	    shift
	    ;;
        --add-kernel|--add-multiboot|--mbargs|--mounts|--boot-filesystem|\
        --bootloader-probe|--debug|--devtree|--devtreedir|--elilo|--efi|\
        --extlinux|--grub|--lilo|--output-file|--remove-mbargs|--silo|\
        --remove-multiboot|--slilo|--yaboot)
            echo
            echo "${SCRIPTNAME}: the option \"${1}\" was deprecated" >&2
            echo "Try '${SCRIPTNAME} --help' to list supported options" >&2
            echo
	    exit 1
	    ;;
        --)
            shift
            break
            ;;
        *)
            echo
            echo "${SCRIPTNAME}: invalid option \"${1}\"" >&2
            echo "Try '${SCRIPTNAME} --help' for more information" >&2
            echo
            exit 1
            ;;
    esac
    shift
done

if [[ -z $blsdir ]]; then
    blsdir="/boot/loader/entries"
fi

if [[ -z $env ]]; then
    env="/boot/grub2/grubenv"
fi

if [[ -z $zipl_config ]]; then
    zipl_config="/etc/zipl.conf"
fi

get_bls_values

default_index="$(get_default_index)"

if [[ -n $display_default ]]; then
    display_default_value
fi

if [[ -n $display_info ]]; then
    display_info_values "${display_info}"
fi

if [[ $bootloader = grub2 ]]; then
    remove_var_prefix
fi

if [[ -n $kernel ]]; then
    if [[ $copy_default = "true" ]]; then
	opts="${bls_options[$default_index]}"
	if [[ -n $args ]]; then
	    opts="${opts} ${args}"
	fi
    else
	opts="${args}"
    fi

    add_bls_fragment "${kernel}" "${title}" "${opts}" "${initrd}" \
                     "${extra_initrd}"
fi

if [[ -n $remove_kernel ]]; then
    remove_bls_fragment "${remove_kernel}"
fi

if [[ -n $update_kernel ]]; then
    update_bls_fragment "${update_kernel}" "${remove_args}" "${args}" "${initrd}"
fi

if [[ -n $set_default ]]; then
    set_default_bls "${set_default}"
fi

exit 0