#!/bin/sh

######################################################################

# Prune undesired systemd.debug entries in kernels that are not

# marked for debugging. See Red Hat bugzilla 1285601.

######################################################################

PATH=/usr/bin:/usr/sbin

EPOCH_DATE=$(date +"%s")

LOG_DIR="/var/log"

LOG_FILE="${LOG_DIR}/grubby_prune_debug"

display_event()

{

    EVENT_LABEL="$1"

    EVENT_DATA="$2"

    JUSTIFIED_LABEL=$(printf "%-12s" "${EVENT_LABEL}")

    LOG_TIMESTAMP=$(date +"%s")

    echo "[${LOG_TIMESTAMP}] ${JUSTIFIED_LABEL}: ${EVENT_DATA}" >> "${LOG_FILE}"

}

exit_event()

{

    display_event "Exit" "Exiting script"

    exit $1

}

find_entry_by_title()

{

    SEARCH_TITLE=$1

    display_event "Examine" "Searching for entry title - ${SEARCH_TITLE}"

    for current_index in $(grubby --info=ALL|grep "^index="| sed 's/^index=//') ; do

        CURRENT_TITLE=$(grubby --info="${current_index}" 2> /dev/null |grep "^title=" | sed 's/^title=//')

        # do not do anything if this was empty

        [ -z "${CURRENT_TITLE}" ] && continue

        if [ "${CURRENT_TITLE}" = "${SEARCH_TITLE}" ]; then

            echo "${current_index}"

            break;

        fi

    done

}

[ -d "${LOG_DIR}" ] || mkdir -p -m 0755 "${LOG_DIR}"

display_event "Start" "Begin search for extraneous debug arguments"

if [ "$(id -u)" -ne 0 ]; then

    display_event "Error" "This script may only run as root."

    exit_event 0

fi

######################################################################

# Back up the grub.cfg for sanity

######################################################################

BOOTLOADER_CFG=

BOOTLOADER_CFG_BK=

if [ -f "/etc/grub2.cfg" ]; then

    BOOTLOADER_CFG=$(realpath "/etc/grub2.cfg")

    BOOTLOADER_CFG_BK="${BOOTLOADER_CFG}.${EPOCH_DATE}.rpmsave"

elif [ -f "/etc/grub2-efi.cfg" ]; then

    BOOTLOADER_CFG=$(realpath "/etc/grub2-efi.cfg")

    BOOTLOADER_CFG_BK="${BOOTLOADER_CFG}.${EPOCH_DATE}.rpmsave"

elif [ -f "/etc/zipl.conf" ]; then

    BOOTLOADER_CFG=$(realpath "/etc/zipl.conf")

    BOOTLOADER_CFG_BK="${BOOTLOADER_CFG}.${EPOCH_DATE}.rpmsave"

elif [ -f "/etc/yaboot.conf" ]; then

    BOOTLOADER_CFG=$(realpath "/etc/yaboot.conf")

    BOOTLOADER_CFG_BK="${BOOTLOADER_CFG}.${EPOCH_DATE}.rpmsave"

fi

if [ -z "${BOOTLOADER_CFG}" ]; then

    display_event "Error" "Could not find a bootloader configuration to back up"

    exit_event 0

fi

if [ -f "${BOOTLOADER_CFG}" ]; then

    if cp -a "${BOOTLOADER_CFG}" "${BOOTLOADER_CFG_BK}" 2> /dev/null; then

        display_event "Copied" \

            "Current configuration backed up to ${BOOTLOADER_CFG_BK}"

    else

        display_event "Error" "Could not write ${BOOTLOADER_CFG_BK}"

        exit_event 0

    fi

fi

######################################################################

#  Figure out what the debugging tag will look like

######################################################################

ARCH=$(uname -m)

if [ $ARCH = 's390' -o $ARCH = 's390x' ]; then

    DEBUGGING_TAG="_with_debugging"

else

    DEBUGGING_TAG=" with debugging"

fi

######################################################################

# Remove the systemd.debug kernel arguments from standard non-debug

# kernel entries only

######################################################################

display_event "Examine" "Searching for distribution provided debugging entries"

for entry_index in $(grubby --info=ALL|grep "^index="| sed 's/^index=//') ; do

    INDEX_TITLE=$(grubby --info="${entry_index}" 2> /dev/null |grep "^title=" | sed 's/^title=//')

    # do not do anything if this was empty

    [ -z "${INDEX_TITLE}" ] && continue

    if echo "${INDEX_TITLE}" | grep -q "${DEBUGGING_TAG}$"; then

        display_event "Found" "Found distribution provided debugging entry - ${INDEX_TITLE}"

        NON_DEBUG_TITLE=$(echo "${INDEX_TITLE}" | sed "s/${DEBUGGING_TAG}$//")

        NON_DEBUG_INDEX=$(find_entry_by_title "${NON_DEBUG_TITLE}")

        if [ -n "${NON_DEBUG_INDEX}" ]; then

            display_event "Found" "Found matching non-debugging entry - ${NON_DEBUG_TITLE}"

            KERNEL_ARGS=$(grubby --info="${NON_DEBUG_INDEX}" 2> /dev/null |grep "^args=")

            if echo "${KERNEL_ARGS}" | grep -E -q 'systemd.debug|systemd.log_level=debug|systemd.log_target=kmsg'; then

                if grubby --update-kernel="${NON_DEBUG_INDEX}" --remove-args="systemd.debug systemd.log_level=debug systemd.log_target=kmsg"; then

                    display_event "Update" "Removed debugging arguments for ${NON_DEBUG_TITLE}"

                else

                    display_event "Error" "grubby failed to remove debug argument from ${NON_DEBUG_TITLE}"

                fi

            else

                display_event "Skip" "No debugging arguments to remove for ${NON_DEBUG_TITLE}"

            fi

        else

            display_event "Error" "Could not find the matching non-debugging entry - ${NON_DEBUG_TITLE}"

        fi

    fi

done

######################################################################

# The default entry should not have debugging statements

######################################################################

# source of ALLOW_DEBUGGING_DEFAULT

[ -f /etc/sysconfig/kernel ] && . /etc/sysconfig/kernel

CURRENT_DEFAULT_INDEX=$(grubby --default-index)

CURRENT_TITLE=$(grubby --info="${CURRENT_DEFAULT_INDEX}" 2> /dev/null |grep "^title=" | sed 's/^title=//')

if echo "${CURRENT_TITLE}" | grep -q "${DEBUGGING_TAG}$"; then

    case "${ALLOW_DEBUGGING_DEFAULT}" in

        [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1)

            display_event "Examine" "Detected user preference to allow debugging default entries if present"

            exit_event 0

            ;;

    esac

    display_event "Examine" "Search for entry without debugging to replace default entry - ${CURRENT_TITLE}"

    unset NON_DEBUG_INDEX

    unset NON_DEBUG_TITLE

    ARCH=$(uname -m)

    NON_DEBUG_TITLE=$(echo "${CURRENT_TITLE}" | sed "s/${DEBUGGING_TAG}$//")

    NON_DEBUG_INDEX=$(find_entry_by_title "${NON_DEBUG_TITLE}")

    if [ -n "${NON_DEBUG_INDEX}" ]; then

        if grubby --set-default-index="${NON_DEBUG_INDEX}"; then

            display_event "Update" "Selected ${NON_DEBUG_TITLE} as the new default entry"

        else

            display_event "Error" "Could not set ${NON_DEBUG_TITLE} as default"

        fi

    else

        display_event "Error" "Could not find the matching non-debugging entry"

    fi

fi

exit_event 0