From 1d7e8a74bb6c282ebe6c9193e4bd0218ec689e46 Mon Sep 17 00:00:00 2001

From: Josh Poimboeuf <jpoimboe@redhat.com>

Date: Wed, 17 Aug 2022 12:21:04 -0700

Subject: [PATCH 106/108] kpatch-build: support Linux 5.19 .cmd file format

Rewrite kobj_find() to deal with Linux 5.19, where the .cmd files use

object file paths relative to the .cmd file rather than relative to the

root of the kernel tree.

While at it, add several performance enhancements to prevent all

currently known deep finds.

This is all quite fiddly.  But it works.

Fixes #1277.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>

---

 kpatch-build/kpatch-build | 243 +++++++++++++++++++++++++++++---------

 1 file changed, 188 insertions(+), 55 deletions(-)

diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build

index 5435a19..bec8010 100755

--- a/kpatch-build/kpatch-build

+++ b/kpatch-build/kpatch-build

@@ -434,82 +434,215 @@ find_special_section_data() {

 	return

 }

-filter_parent_obj()

-{

-  local dir="${1}"

-  local file="${2}"

+# path of file, relative to dir

+# adapted from https://stackoverflow.com/a/24848739

+relpath() {

+	local file="$1"

+	local dir="$2"

+

+	local filedir

+	local common

+	local result

+

+	filedir="$(dirname "$(readlink -f "$file")")"

+	common="$(readlink -f "$dir")"

+

+	if [[ "$filedir" = "$common" ]]; then

+		basename "$file"

+		return

+	fi

+

+	while [[ "${filedir#$common/}" = "$filedir" ]]; do

+		common="$(dirname "$common")"

+		result="../$result"

+	done

-  grep -v "\.mod\.cmd$" | grep -Fv "${dir}/.${file}.cmd"

+	result="${result}${filedir#$common/}"

+	echo "${result}/$(basename "$file")"

 }

-find_parent_obj() {

-	dir="$(dirname "$1")"

-	absdir="$(readlink -f "$dir")"

-	pwddir="$(readlink -f .)"

-	pdir="${absdir#$pwddir/}"

-	file="$(basename "$1")"

-	grepname="${1%.o}"

-	grepname="$grepname\\.o"

-	if [[ "$DEEP_FIND" -eq 1 ]]; then

-		num=0

-		if [[ -n "$last_deep_find" ]]; then

-			parent="$(grep -lw "$grepname" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | head -n1)"

-			num="$(grep -lw "$grepname" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | wc -l)"

+cmd_file_to_o_file() {

+	local parent="$1"

+

+	# convert cmd file name to corresponding .o

+	parent_dir="$(dirname "$parent")"

+	parent_dir="${parent_dir#./}"

+	parent="$(basename "$parent")"

+	parent="${parent#.}"

+	parent="${parent%.cmd}"

+	parent="$parent_dir/$parent"

+

+	[[ -f $parent ]] || die "can't find $parent associated with $1"

+

+	echo "$parent"

+}

+

+get_parent_from_parents() {

+	local parents=("$@")

+

+	[[ ${#parents[@]} -eq 0 ]] && PARENT="" && return

+	[[ ${#parents[@]} -eq 1 ]] && PARENT="${parents[0]}" && return

+

+	# multiple parents:

+	local parent

+	local mod_name="${parents[0]%.*}"

+	local mod_file

+	for parent in "${parents[@]}"; do

+		# for modules, there can be multiple matches.  Some

+		# combination of foo.o, foo.mod, and foo.ko, depending

+		# on kernel version and whether the module is single or

+		# multi-object.  Make sure a .mod and/or .ko exists, and no

+		# more than one .mod/.ko exists.

+

+		[[ $parent = *.o ]] && continue

+

+		if [[ ${parent%.*} != "$mod_name" ]]; then

+			mod_file=""

+			break

 		fi

-		if [[ "$num" -eq 0 ]]; then

-			parent="$(find . -name ".*.cmd" -print0 | xargs -0 grep -lw "$grepname" | filter_parent_obj "${pdir}" "${file}" | cut -c3- | head -n1)"

-			num="$(find . -name ".*.cmd" -print0 | xargs -0 grep -lw "$grepname" | filter_parent_obj "${pdir}" "${file}" | wc -l)"

-			[[ "$num" -eq 1 ]] && last_deep_find="$(dirname "$parent")"

+

+		if [[ $parent = *.mod || $parent = *.ko ]]; then

+			mod_file=$parent

+			continue

 		fi

+

+		mod_file=""

+		break

+	done

+

+	if [[ -n $mod_file ]]; then

+		PARENT="$mod_file"

+		return

+	fi

+

+	ERROR_IF_DIFF="multiple parent matches for $file: ${parents[*]}"

+	PARENT="${parents[0]}"

+}

+

+__find_parent_obj_in_dir() {

+	local file="$1"

+	local dir="$2"

+

+	declare -a parents

+

+	while IFS='' read -r parent; do

+		parent="$(cmd_file_to_o_file "$parent")"

+		[[ $parent -ef $file ]] && continue

+		parents+=("$parent")

+	done < <(grep -El "[ 	]${file/./\\.}([ 	\)]|$)" "$dir"/.*.cmd)

+

+	get_parent_from_parents "${parents[@]}"

+}

+

+find_parent_obj_in_dir() {

+	local file="$1"

+	local dir="$2"

+

+	# make sure the dir has .cmd files

+	if ! compgen -G "$dir"/.*.cmd > /dev/null; then

+		PARENT=""

+		return

+	fi

+

+	# 5.19+: ../acp/acp_hw.o

+	__find_parent_obj_in_dir "$(relpath "$file" "$dir")" "$dir"

+	[[ -n $PARENT ]] && return

+

+	# pre-5.19 (and 5.19+ single-object modules):

+	if [[ $file == $dir* ]]; then

+		# arch/x86/kernel/smp.o

+		__find_parent_obj_in_dir "$file" "$dir"

 	else

-		parent="$(grep -lw "$grepname" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | head -n1)"

-		num="$(grep -lw "$grepname" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | wc -l)"

+		# drivers/gpu/drm/amd/amdgpu/../acp/acp_hw.o

+		__find_parent_obj_in_dir "$dir"/"$(relpath "$file" "$dir")" "$dir"

 	fi

+}

-	[[ "$num" -eq 0 ]] && PARENT="" && return

-	[[ "$num" -gt 1 ]] && ERROR_IF_DIFF="two parent matches for $1"

+find_parent_obj() {

+	local file="$1"

+

+	# common case: look in same directory

+	find_parent_obj_in_dir "$file" "$(dirname "$file")"

+	[[ -n $PARENT ]] && return

-	dir="$(dirname "$parent")"

-	PARENT="$(basename "$parent")"

-	PARENT="${PARENT#.}"

-	PARENT="${PARENT%.cmd}"

-	[[ $dir != "." ]] && PARENT="$dir/$PARENT"

-	[[ ! -e "$PARENT" ]] && die "ERROR: can't find parent $PARENT for $1"

+	# if we previously had a successful deep find, try that dir first

+	if [[ -n "$LAST_DEEP_FIND_DIR" ]]; then

+		find_parent_obj_in_dir "$file" "$LAST_DEEP_FIND_DIR"

+		[[ -n "$PARENT" ]] && return

+	fi

+

+	# prevent known deep finds

+	if [[ $file = drivers/gpu/drm/amd/* ]]; then

+		find_parent_obj_in_dir "$file" "drivers/gpu/drm/amd/amdgpu"

+		[[ -n "$PARENT" ]] && return

+	fi

+	if [[ $file = virt/kvm/* ]]; then

+		find_parent_obj_in_dir "$file" "arch/x86/kvm"

+		[[ -n "$PARENT" ]] && return

+	fi

+	if [[ $file = drivers/oprofile/* ]]; then

+		find_parent_obj_in_dir "$file" "arch/x86/oprofile"

+		[[ -n "$PARENT" ]] && return

+	fi

+

+	# check higher-level dirs

+	local dir

+	dir="$(dirname "$file")"

+	while [[ ! $dir -ef . ]]; do

+		dir="$(dirname "$dir")"

+		find_parent_obj_in_dir "$file" "$dir"

+		[[ -n $PARENT ]] && return

+	done

+

+	# slow path: search the entire tree ("deep find")

+	echo 'doing "deep find" for parent object'

+	declare -a parents

+	while IFS= read -r -d '' dir; do

+		find_parent_obj_in_dir "$file" "$dir"

+		if [[ -n $PARENT ]]; then

+			parents+=("$PARENT")

+			LAST_DEEP_FIND_DIR="$dir"

+		fi

+	done < <(find . -type d -print0)

+

+	get_parent_from_parents "${parents[@]}"

 }

+# find vmlinux or .ko associated with a .o file

 find_kobj() {

-	arg="$1"

+	local file="$1"

 	if [[ -n $OOT_MODULE ]]; then

 		KOBJFILE="$OOT_MODULE"

 		return

 	fi

-	KOBJFILE="$arg"

-	DEEP_FIND=0

+	KOBJFILE="$file"

 	ERROR_IF_DIFF=

 	while true; do

+		case "$KOBJFILE" in

+			*.mod)

+				KOBJFILE=${PARENT/.mod/.ko}

+				[[ -e $KOBJFILE ]] || die "can't find .ko for $PARENT"

+				return

+				;;

+			*.ko)

+				return

+				;;

+			*/built-in.o|\

+			*/built-in.a|\

+			arch/x86/kernel/ebda.o|\

+			arch/x86/kernel/head*.o|\

+			arch/x86/kernel/platform-quirks.o|\

+			arch/x86/lib/lib.a|\

+			lib/lib.a)

+				KOBJFILE=vmlinux

+				return

+				;;

+		esac

+

 		find_parent_obj "$KOBJFILE"

-		[[ -n "$PARENT" ]] && DEEP_FIND=0

-		if [[ -z "$PARENT" ]]; then

-			[[ "$KOBJFILE" = *.ko ]] && return

-			case "$KOBJFILE" in

-				*/built-in.o|\

-				*/built-in.a|\

-				arch/x86/lib/lib.a|\

-				arch/x86/kernel/head*.o|\

-				arch/x86/kernel/ebda.o|\

-				arch/x86/kernel/platform-quirks.o|\

-				lib/lib.a)

-					KOBJFILE=vmlinux

-					return

-			esac

-			if [[ "$DEEP_FIND" -eq 0 ]]; then

-				DEEP_FIND=1

-				continue;

-			fi

-			die "invalid ancestor $KOBJFILE for $arg"

-		fi

+		[[ -z "$PARENT" ]] && die "invalid ancestor $KOBJFILE for $file"

 		KOBJFILE="$PARENT"

 	done

 }

-- 

2.37.3