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gentoo-full-overlay/eclass/dist-kernel-utils.eclass

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# Copyright 2020-2022 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
# @ECLASS: dist-kernel-utils.eclass
# @MAINTAINER:
# Distribution Kernel Project <dist-kernel@gentoo.org>
# @AUTHOR:
# Michał Górny <mgorny@gentoo.org>
# @SUPPORTED_EAPIS: 7 8
# @BLURB: Utility functions related to Distribution Kernels
# @DESCRIPTION:
# This eclass provides various utility functions related to Distribution
# Kernels.
if [[ ! ${_DIST_KERNEL_UTILS} ]]; then
case ${EAPI} in
7|8) ;;
*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
esac
# @FUNCTION: dist-kernel_build_initramfs
# @USAGE: <output> <version>
# @DESCRIPTION:
# Build an initramfs for the kernel. <output> specifies the absolute
# path where initramfs will be created, while <version> specifies
# the kernel version, used to find modules.
#
# Note: while this function uses dracut at the moment, other initramfs
# variants may be supported in the future.
dist-kernel_build_initramfs() {
debug-print-function ${FUNCNAME} "${@}"
[[ ${#} -eq 2 ]] || die "${FUNCNAME}: invalid arguments"
local output=${1}
local version=${2}
local rel_image_path=$(dist-kernel_get_image_path)
local image=${output%/*}/${rel_image_path##*/}
local args=(
--force
# if uefi=yes is used, dracut needs to locate the kernel image
--kernel-image "${image}"
# positional arguments
"${output}" "${version}"
)
ebegin "Building initramfs via dracut"
dracut "${args[@]}"
eend ${?} || die -n "Building initramfs failed"
}
# @FUNCTION: dist-kernel_get_image_path
# @DESCRIPTION:
# Get relative kernel image path specific to the current ${ARCH}.
dist-kernel_get_image_path() {
case ${ARCH} in
amd64|x86)
echo arch/x86/boot/bzImage
;;
arm64)
echo arch/arm64/boot/Image.gz
;;
arm)
echo arch/arm/boot/zImage
;;
hppa|ppc|ppc64)
# https://www.kernel.org/doc/html/latest/powerpc/bootwrapper.html
# ./ is required because of ${image_path%/*}
# substitutions in the code
echo ./vmlinux
;;
riscv)
echo arch/riscv/boot/Image.gz
;;
*)
die "${FUNCNAME}: unsupported ARCH=${ARCH}"
;;
esac
}
# @FUNCTION: dist-kernel_install_kernel
# @USAGE: <version> <image> <system.map>
# @DESCRIPTION:
# Install kernel using installkernel tool. <version> specifies
# the kernel version, <image> full path to the image, <system.map>
# full path to System.map.
dist-kernel_install_kernel() {
debug-print-function ${FUNCNAME} "${@}"
[[ ${#} -eq 3 ]] || die "${FUNCNAME}: invalid arguments"
local version=${1}
local image=${2}
local map=${3}
# if dracut is used in uefi=yes mode, initrd will actually
# be a combined kernel+initramfs UEFI executable. we can easily
# recognize it by PE magic (vs cpio for a regular initramfs)
local initrd=${image%/*}/initrd
local magic
[[ -s ${initrd} ]] && read -n 2 magic < "${initrd}"
if [[ ${magic} == MZ ]]; then
einfo "Combined UEFI kernel+initramfs executable found"
# install the combined executable in place of kernel
image=${initrd}.uefi
mv "${initrd}" "${image}" || die
# put an empty file in place of initrd. installing a duplicate
# file would waste disk space, and removing it entirely provokes
# kernel-install to regenerate it via dracut.
> "${initrd}"
fi
ebegin "Installing the kernel via installkernel"
# note: .config is taken relatively to System.map;
# initrd relatively to bzImage
installkernel "${version}" "${image}" "${map}"
eend ${?} || die -n "Installing the kernel failed"
}
# @FUNCTION: dist-kernel_reinstall_initramfs
# @USAGE: <kv-dir> <kv-full>
# @DESCRIPTION:
# Rebuild and install initramfs for the specified dist-kernel.
# <kv-dir> is the kernel source directory (${KV_DIR} from linux-info),
# while <kv-full> is the full kernel version (${KV_FULL}).
# The function will determine whether <kernel-dir> is actually
# a dist-kernel, and whether initramfs was used.
#
# This function is to be used in pkg_postinst() of ebuilds installing
# kernel modules that are included in the initramfs.
dist-kernel_reinstall_initramfs() {
debug-print-function ${FUNCNAME} "${@}"
[[ ${#} -eq 2 ]] || die "${FUNCNAME}: invalid arguments"
local kernel_dir=${1}
local ver=${2}
local image_path=${kernel_dir}/$(dist-kernel_get_image_path)
local initramfs_path=${image_path%/*}/initrd
if [[ ! -f ${image_path} ]]; then
eerror "Kernel install missing, image not found:"
eerror " ${image_path}"
eerror "Initramfs will not be updated. Please reinstall your kernel."
return
fi
if [[ ! -f ${initramfs_path} ]]; then
einfo "No initramfs found at ${initramfs_path}"
return
fi
dist-kernel_build_initramfs "${initramfs_path}" "${ver}"
dist-kernel_install_kernel "${ver}" "${image_path}" \
"${kernel_dir}/System.map"
}
# @FUNCTION: dist-kernel_PV_to_KV
# @USAGE: <pv>
# @DESCRIPTION:
# Convert a Gentoo-style ebuild version to kernel "x.y.z[-rcN]" version.
dist-kernel_PV_to_KV() {
debug-print-function ${FUNCNAME} "${@}"
[[ ${#} -ne 1 ]] && die "${FUNCNAME}: invalid arguments"
local pv=${1}
local kv=${pv%%_*}
[[ -z $(ver_cut 3- "${kv}") ]] && kv+=".0"
[[ ${pv} == *_* ]] && kv+=-${pv#*_}
echo "${kv}"
}
_DIST_KERNEL_UTILS=1
fi