#!/bin/sh -e
#
# brp-sign-kmodules - sign Linux kernel modules
#
# Copyright (C) 2020 Vitaly Chikunov <vt@altlinux.org>
#
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#

. @RPMCONFIGDIR@/rpmb-functions
ValidateBuildRoot

cd "$RPM_BUILD_ROOT" || exit

# We need modules and kernel tree to work.
[ -d lib/modules ] || exit 0
[ -d boot ] || exit 0

# Find kernel build root.
kbuilddir=$(find "$RPM_BUILD_DIR" -depth -maxdepth 3 -type f -name MAINTAINERS -print -quit)
kbuilddir=${kbuilddir%/*}
if [ -z "$kbuilddir" ]; then
	Warning "Kernel source directory not found."
	exit 0
fi

# Determine build time `.config'. Allow 2 levels for builds in O=subdir.
kconfig=$(find "$kbuilddir" -depth -maxdepth 2 -type f -name .config -print -quit)
if [ -z "$kconfig" ]; then
	Warning "Kernel build output directory not found."
	exit 0
fi

# Kernel output dir (from O=)
koutput=${kconfig%/.config}

# Working requirement.
if [ ! -x "$koutput/scripts/sign-file" ]; then
	Warning "scripts/sign-file executable not found."
	exit 0
fi

get_config() {
	"$kbuilddir/scripts/config" --file "$kconfig" -s "$1"
}

MODULE_SIG_ALL=$( get_config  MODULE_SIG_ALL)
MODULE_SIG_HASH=$(get_config  MODULE_SIG_HASH)
MODULE_SIG_KEY=$( get_config  MODULE_SIG_KEY)
MODULE_SIG_CERT=certs/signing_key.x509

# CONFIG_MODULE_SIG_ALL=y means that the modules were already signed
# during the kernel's make modules_install.  But these modules may have
# been debugedit(1)ed and strip(1)ped to detach the debuginfo and
# therefore lost their signatures.
# This brp-script is intended only for resigning such modules.

if [ "$MODULE_SIG_ALL" != "y" ]; then
	Warning "Module signing is not enabled (CONFIG_MODULE_SIG_ALL=$MODULE_SIG_ALL)"
	exit 0
fi
if [ -z "$MODULE_SIG_HASH" ] || [ "$MODULE_SIG_HASH" = undef ]; then
	Warning "Module signing hash is not set (CONFIG_MODULE_SIG_HASH)"
	exit 0
fi
if [ -z "$MODULE_SIG_KEY" ] || [ "$MODULE_SIG_KEY" = undef ]; then
	Warning "Module signing key is not set (CONFIG_MODULE_SIG_KEY)"
	exit 0
fi

sig_key=$koutput/$MODULE_SIG_KEY
if [ ! -f "$sig_key" ]; then
	Warning "Signing key not found (CONFIG_MODULE_SIG_KEY=\"$MODULE_SIG_KEY\")"
	exit 0
fi

sig_cert=$koutput/$MODULE_SIG_CERT
if [ ! -f "$sig_cert" ]; then
	Warning "Signing cert not found (expected $MODULE_SIG_CERT)"
	exit 0
fi

find "$RPM_BUILD_ROOT/lib/modules" \( -name '*.ko' -or -name '*.ko.*' \) > .kmodules
num=$(wc -l < .kmodules)
if [ "$num" -eq 0 ]; then
	Warning "No kernel modules found for singing."
	exit 0
fi

# Verify that singing is working to avoid flooding with errors later.
cd "$koutput"
t=$(mktemp)
if ! scripts/sign-file "$MODULE_SIG_HASH" "$MODULE_SIG_KEY" "$MODULE_SIG_CERT" "$t"; then
	Warning "Test signing failed (scripts/sign-file error)."
	exit 0
fi
rm "$t"
cd "$RPM_BUILD_ROOT"

# Determine if we should uncompress.
read -r f < .kmodules
rezip=

ext="${f##*.}"
case "$ext" in
	ko) ;;
	gz) rezip=gzip ;;
	xz) rezip='xz --lzma2=dict=2MiB' ;;
	zst) rezip='zstd --rm -q' ;;
	*) Warning "$ext compression is not supported yet."; exit 0 ;;
esac

nproc="$(nproc)"

if [ -n "$rezip" ]; then
	Info "Uncompress ($rezip) $num modules before signing."
	xargs -P"$nproc" $rezip --decompress < .kmodules
fi

cd "$koutput"
Info "Signing $num modules in $RPM_BUILD_ROOT (hash $MODULE_SIG_HASH key $MODULE_SIG_KEY)"

[ "$ext" = ko ] ||
	sed "s/\.ko\.$ext$/.ko/" -i "$RPM_BUILD_ROOT/.kmodules"

xargs -P"$nproc" -n1 <"$RPM_BUILD_ROOT/.kmodules" scripts/sign-file "$MODULE_SIG_HASH" "$MODULE_SIG_KEY" "$MODULE_SIG_CERT"

cd "$RPM_BUILD_ROOT"

if [ -n "$rezip" ]; then
	Info "Compress ($rezip) $num modules after signing."
	xargs -P"$nproc" <.kmodules $rezip
fi

rm .kmodules