# Copyright 1999-2023 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=8

inherit flag-o-matic linux-mod-r1

if [[ "${PV}" == "9999" ]]; then
	inherit git-r3
	EGIT_REPO_URI="https://github.com/dynup/${PN}.git"
else
	SRC_URI="https://github.com/dynup/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz"
	KEYWORDS="~amd64"
fi

DESCRIPTION="Dynamic kernel patching for Linux"
HOMEPAGE="https://github.com/dynup/kpatch"

LICENSE="GPL-2+"
SLOT="0"
IUSE="contrib +kpatch +kpatch-build kmod test"
RESTRICT="!test? ( test )"

RDEPEND="
	app-crypt/pesign
	sys-libs/zlib
	sys-apps/pciutils
"

DEPEND="
	${RDEPEND}
	dev-libs/elfutils
	sys-devel/bison
	test? ( || ( dev-util/shellcheck-bin dev-util/shellcheck ) )
"

pkg_setup() {
	if use kmod; then
		if kernel_is gt 3 9 0; then
			if ! linux_config_exists; then
				eerror "Unable to check the currently running kernel for kpatch support"
				eerror "Please be sure a .config file is available in the kernel src dir"
				eerror "and ensure the kernel has been built."
			else
				# Fail to build if these kernel options are not enabled (see kpatch/kmod/core/Makefile)
				CONFIG_CHECK="FUNCTION_TRACER HAVE_FENTRY MODULES SYSFS KALLSYMS_ALL"
				ERROR_FUNCTION_TRACER="CONFIG_FUNCTION_TRACER must be enabled in the kernel's config file"
				ERROR_HAVE_FENTRY="CONFIG_HAVE_FENTRY must be enabled in the kernel's config file"
				ERROR_MODULES="CONFIG_MODULES must be enabled in the kernel's config file"
				ERROR_SYSFS="CONFIG_SYSFS must be enabled in the kernel's config file"
				ERROR_KALLSYMS_ALL="CONFIG_KALLSYMS_ALL must be enabled in the kernel's config file"
			fi
		else
			eerror
			eerror "kpatch is not available for Linux kernels below 4.0.0"
			eerror
			die "Upgrade the kernel sources before installing kpatch."
		fi
		check_extra_config
	fi

}

src_prepare() {
	replace-flags '-O?' '-O1'
	default
}

src_compile() {
	use kpatch-build && emake -C kpatch-build
	use kpatch && emake -C kpatch
	use kmod && set_arch_to_kernel && emake -C kmod
	use contrib && emake -C contrib
	use test && emake check
}

src_install() {
	if use kpatch-build; then
		emake DESTDIR="${D}" PREFIX="/usr" install -C kpatch-build
		insinto /usr/share/${PN}/patch
		doins kmod/patch/kpatch{.lds.S,-macros.h,-patch.h,-patch-hook.c}
		doins kmod/patch/{livepatch-patch-hook.c,Makefile,patch-hook.c}
		doins kmod/core/kpatch.h
		doman man/kpatch-build.1
	fi

	if use kpatch; then
		emake DESTDIR="${D}" PREFIX="/usr" install -C kpatch
		doman man/kpatch.1
	fi

	use kmod && set_arch_to_kernel && emake DESTDIR="${D}" PREFIX="/usr" install -C kmod
	use contrib && emake DESTDIR="${D}" PREFIX="/usr" install -C contrib

	dodoc README.md doc/patch-author-guide.md
}