golden hour

/usr/lib/kernel/install.d

File/Folder	Size	Actions
10-devicetree.install	1.92 KB
20-grub.install	7.98 KB
20-grubby.install	1.86 KB
50-depmod.install	1.96 KB
50-dracut.install	1.85 KB
51-dracut-rescue.install	3.79 KB
60-kdump.install	791 B
90-loaderentry.install	5.5 KB
90-uki-copy.install	3.09 KB
92-crashkernel.install	204 B
92-tuned.install	1.62 KB
95-kernel-hooks.install	675 B
99-grub-mkconfig.install	1.02 KB

Edit: 20-grub.install

#!/usr/bin/bash

if ! [[ $KERNEL_INSTALL_MACHINE_ID ]]; then
    exit 0
fi

[[ -f /etc/default/grub ]] && . /etc/default/grub
[[ -f /etc/os-release ]] && . /etc/os-release

COMMAND="$1"
KERNEL_VERSION="$2"
BOOT_DIR_ABS="$3"
KERNEL_IMAGE="$4"

KERNEL_DIR="${KERNEL_IMAGE%/*}"

MACHINE_ID=$KERNEL_INSTALL_MACHINE_ID

# If ${BOOT_DIR_ABS} exists, some other boot loader is active.
[[ -d "${BOOT_DIR_ABS}" ]] && exit 0

# UKIs are BLS type 2 entries, 90-uki-copy.install takes care of them
[ "x$KERNEL_INSTALL_LAYOUT" != "xuki" ] || exit 0

BLS_DIR="/boot/loader/entries"

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

local debugname=""
    local debugid=""
    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 /vmlinuz-${kernelver}
initrd /initramfs-${kernelver}.img
options ${kernelopts}
grub_users \$grub_users
grub_arg --unrestricted
grub_class ${ID}
EOF
}

[[ "$KERNEL_VERSION" == *\+* ]] && flavor=-"${KERNEL_VERSION##*+}"
case "$COMMAND" in
    add)
        if [[ "${KERNEL_DIR}" != "/boot" ]]; then
            for i in \
                "$KERNEL_IMAGE" \
                    "$KERNEL_DIR"/System.map \
                    "$KERNEL_DIR"/config \
                    "$KERNEL_DIR"/zImage.stub \
                    "$KERNEL_DIR"/dtb
            do
                [[ -e "$i" ]] || continue
                rm -f "/boot/${i##*/}-${KERNEL_VERSION}"
                cp -aT "$i" "/boot/${i##*/}-${KERNEL_VERSION}"
                command -v restorecon &>/dev/null && \
                    restorecon -R "/boot/${i##*/}-${KERNEL_VERSION}"
            done
            # hmac is .vmlinuz-<version>.hmac so needs a special treatment
            i="$KERNEL_DIR/.${KERNEL_IMAGE##*/}.hmac"
            if [[ -e "$i" ]]; then
                rm -f "/boot/.${KERNEL_IMAGE##*/}-${KERNEL_VERSION}.hmac"
                cp -a "$i" "/boot/.${KERNEL_IMAGE##*/}-${KERNEL_VERSION}.hmac"
                command -v restorecon &>/dev/null && \
                    restorecon "/boot/.${KERNEL_IMAGE##*/}-${KERNEL_VERSION}.hmac"
            fi
            # symvers is symvers-<version>.gz symlink, needs a special treatment
            i="$KERNEL_DIR/symvers.gz"
            if [[ -e "$i" ]]; then
                rm -f "/boot/symvers-${KERNEL_VERSION}.gz"
                ln -s "$i" "/boot/symvers-${KERNEL_VERSION}.gz"
                command -v restorecon &>/dev/null && \
                    restorecon "/boot/symvers-${KERNEL_VERSION}.gz"
            fi
        fi

if [[ "x${GRUB_ENABLE_BLSCFG}" = "xtrue" ]] || [[ ! -f /sbin/new-kernel-pkg ]]; then
            if [[ -f /etc/kernel/cmdline ]]; then
                read -r -d '' -a BOOT_OPTIONS < /etc/kernel/cmdline
            elif [[ -f /usr/lib/kernel/cmdline ]]; then
                read -r -d '' -a BOOT_OPTIONS < /usr/lib/kernel/cmdline
            else
                declare -a BOOT_OPTIONS

read -r -d '' -a line < /proc/cmdline
                for i in "${line[@]}"; do
                    [[ "${i#initrd=*}" != "$i" ]] && continue
                    [[ "${i#BOOT_IMAGE=*}" != "$i" ]] && continue
                    BOOT_OPTIONS+=("$i")
                done
            fi

eval "$(grub2-get-kernel-settings)" || true
            [[ -d "$BLS_DIR" ]] || mkdir -m 0700 -p "$BLS_DIR"
            BLS_ID="${MACHINE_ID}-${KERNEL_VERSION}"
            BLS_TARGET="${BLS_DIR}/${BLS_ID}.conf"
            mkbls "${KERNEL_VERSION}" \
		  "$(date -u +%Y%m%d%H%M%S -d "$(stat -c '%y' "${KERNEL_DIR}")")" \
                  "${BOOT_OPTIONS[*]}" >"${BLS_TARGET}"
            command -v restorecon &>/dev/null && restorecon -R "${BLS_TARGET}"

LINUX="$(grep '^linux[ \t]' "${BLS_TARGET}" | sed -e 's,^linux[ \t]*,,')"
            INITRD="$(grep '^initrd[ \t]' "${BLS_TARGET}" | sed -e 's,^initrd[ \t]*,,')"
            if [[ "$(grub2-probe --device $(grub2-probe --target=device /) --target=fs)" == "btrfs" &&
		      "${SUSE_BTRFS_SNAPSHOT_BOOTING}" == "true" ]]; then
                LINUX_RELPATH="$(grub2-mkrelpath -r /boot${LINUX})"
            else
                LINUX_RELPATH="$(grub2-mkrelpath /boot${LINUX})"
            fi
            BOOTPREFIX="$(dirname ${LINUX_RELPATH})"
            ROOTPREFIX="$(dirname "/boot${LINUX}")"

if [[ $LINUX != $LINUX_RELPATH ]]; then
                sed -i -e "s,^linux.*,linux ${BOOTPREFIX}${LINUX},g" "${BLS_TARGET}"
                sed -i -e "s,^initrd.*,initrd ${BOOTPREFIX}${INITRD},g" "${BLS_TARGET}"
            fi

if ( [[ "$KERNEL_VERSION" != *${GRUB_DEFAULT_KERNEL_TYPE}* ]] && \
                     [ "x$GRUB_NON_STANDARD_KERNEL" == "xtrue" ] ) || \
                   ( echo "$KERNEL_VERSION" | grep -E -q "64k|auto|rt|uki" && \
                     [ "x$GRUB_NON_STANDARD_KERNEL" != "xtrue" ] ) || \
                   ( [[ "$KERNEL_VERSION" == *debug* ]] && [ "x$GRUB_DEFAULT_TO_DEBUG" != "xtrue" ] ); then
                GRUB_UPDATE_DEFAULT_KERNEL=false
            fi

if [ "x$GRUB_UPDATE_DEFAULT_KERNEL" = "xtrue" ]; then
                NEWDEFAULT="${BLS_ID}"
            fi

if [ "x$GRUB_LINUX_MAKE_DEBUG" = "xtrue" ]; then
                BLS_DEBUG="$(echo ${BLS_TARGET} | sed -e "s/${KERNEL_VERSION}/${KERNEL_VERSION}~debug/")"
                cp -aT  "${BLS_TARGET}" "${BLS_DEBUG}"
                TITLE="$(grep '^title[ \t]' "${BLS_DEBUG}" | sed -e 's/^title[ \t]*//')"
                OPTIONS="$(echo "${BOOT_OPTIONS[*]} ${GRUB_CMDLINE_LINUX_DEBUG}" | sed -e 's/\//\\\//g')"
                sed -i -e "s/^title.*/title ${TITLE}${GRUB_LINUX_DEBUG_TITLE_POSTFIX}/" "${BLS_DEBUG}"
                sed -i -e "s/^options.*/options ${OPTIONS}/" "${BLS_DEBUG}"
                if [ -n "$NEWDEFAULT" -a "x$GRUB_DEFAULT_TO_DEBUG" = "xtrue" ]; then
                    NEWDEFAULT="${BLS_DEBUG_ID}"
                fi
            fi
            if [ -n "$NEWDEFAULT" ]; then
                grub2-editenv - set "saved_entry=${NEWDEFAULT}"
            fi

# this probably isn't the best place to do this, but it will do for now.
            if [ -e "${ROOTPREFIX}${INITRD}" -a -e "${ROOTPREFIX}${LINUX}" -a \
                 "${ROOTPREFIX}${INITRD}" -ot "${ROOTPREFIX}${LINUX}" -a \
                 -x /usr/lib/kernel/install.d/50-dracut.install ]; then
                rm -f "${ROOTPREFIX}${INITRD}"
            fi
            exit 0
        fi

/sbin/new-kernel-pkg --package "kernel${flavor}" --install "$KERNEL_VERSION" || exit $?
        /sbin/new-kernel-pkg --package "kernel${flavor}" --mkinitrd --dracut --depmod --update "$KERNEL_VERSION" || exit $?
        /sbin/new-kernel-pkg --package "kernel${flavor}" --rpmposttrans "$KERNEL_VERSION" || exit $?
        # If grubby is used there's no need to run other installation plugins
        exit 77
        ;;
    remove)

if [[ "x${GRUB_ENABLE_BLSCFG}" = "xtrue" ]] || [[ ! -f /sbin/new-kernel-pkg ]]; then
            BLS_TARGET="${BLS_DIR}/${MACHINE_ID}-${KERNEL_VERSION}.conf"
            BLS_DEBUG="$(echo ${BLS_TARGET} | sed -e "s/${KERNEL_VERSION}/${KERNEL_VERSION}~debug/")"
            rm -f "${BLS_TARGET}" "${BLS_DEBUG}"

for i in vmlinuz System.map config zImage.stub dtb; do
                rm -rf "/boot/${i}-${KERNEL_VERSION}"
            done
            # hmac is .vmlinuz-<version>.hmac so needs a special treatment
            rm -f "/boot/.vmlinuz-${KERNEL_VERSION}.hmac"
            # symvers is symvers-<version>.gz symlink, needs a special treatment
            rm -f "/boot/symvers-${KERNEL_VERSION}.gz"

exit 0
        fi

/sbin/new-kernel-pkg --package "kernel${flavor+-$flavor}" --rminitrd --rmmoddep --remove "$KERNEL_VERSION" || exit $?
        # If grubby is used there's no need to run other installation plugins
        exit 77
        ;;
    *)
        ;;
esac