From e9755413ed58c8d40b615552e84ff9c5e80acc57 Mon Sep 17 00:00:00 2001
From: chenzefeng <chenzefeng2@huawei.com>
Date: Tue, 17 Sep 2019 10:44:47 +0800
Subject: [PATCH] kpatch-build: use whole word filename matching in
 find_parent_obj()

Building a kpatch for a module with this Makefile:

The Makefile is as follow:
	obj-m += m_hello.o
	m_hello-y = hello.o
	default:
        	$(MAKE) -C /lib/modules/4.4.21-69-default/build M=$(shell pwd) modules
	clean:
        	$(MAKE) -C /lib/modules/4.4.21-69-default/build M=$(shell pwd) clean

results in kpatch-build "ERROR: two parent matches for hello.o".

The problem is that find_parent_obj() looks for filenames like so:

	% grep -l hello.o ./.*.cmd | grep -Fv hello.o
	.m_hello.ko.cmd
	.m_hello.o.cmd

where .m_hello.ko.cmd is the parant for m_hello.o, and .m_hello.o.cmd is the
parant for hello.o, but because the "hello.o" is a substring of "m_hello.o",
it will cause "m_hello.o" to be matched for the "hello.o" as well.

Fix this by using grep's -w|--word-regexp option to force it to match
whole words instead of substrings.

Signed-off-by: chenzefeng <chenzefeng2@huawei.com>
---
 kpatch-build/kpatch-build | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index 9b8e374..455f398 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -373,17 +373,17 @@ find_parent_obj() {
 	if [[ "$DEEP_FIND" -eq 1 ]]; then
 		num=0
 		if [[ -n "$last_deep_find" ]]; then
-			parent="$(grep -l "$grepname" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | head -n1)"
-			num="$(grep -l "$grepname" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | wc -l)"
+			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)"
 		fi
 		if [[ "$num" -eq 0 ]]; then
-			parent="$(find . -name ".*.cmd" -print0 | xargs -0 grep -l "$grepname" | filter_parent_obj "${pdir}" "${file}" | cut -c3- | head -n1)"
-			num="$(find . -name ".*.cmd" -print0 | xargs -0 grep -l "$grepname" | filter_parent_obj "${pdir}" "${file}" | wc -l)"
+			parent="$(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")"
 		fi
 	else
-		parent="$(grep -l "$grepname" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | head -n1)"
-		num="$(grep -l "$grepname" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | wc -l)"
+		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)"
 	fi
 
 	[[ "$num" -eq 0 ]] && PARENT="" && return
@@ -393,7 +393,7 @@ find_parent_obj() {
 	PARENT="$(basename "$parent")"
 	PARENT="${PARENT#.}"
 	PARENT="${PARENT%.cmd}"
-	PARENT="$dir/$PARENT"
+	[[ $dir != "." ]] && PARENT="$dir/$PARENT"
 	[[ ! -e "$PARENT" ]] && die "ERROR: can't find parent $PARENT for $1"
 }