From 23d3f191a5762c0d73da2090e9cec6d551f5d94a Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Fri, 10 Jan 2020 14:02:24 +0900
Subject: [PATCH] kbuild: remove *.tmp file when filechk fails

[ Upstream commit 88fe89a47153facd8cb2d06d5c8727f7224c43c2 ]

Bartosz Golaszewski reports that when "make {menu,n,g,x}config" fails
due to missing packages, a temporary file is left over, which is not
ignored by git.

For example, if GTK+ is not installed:

  $ make gconfig
  *
  * Unable to find the GTK+ installation. Please make sure that
  * the GTK+ 2.0 development package is correctly installed.
  * You need gtk+-2.0 gmodule-2.0 libglade-2.0
  *
  scripts/kconfig/Makefile:208: recipe for target 'scripts/kconfig/gconf-cfg' failed
  make[1]: *** [scripts/kconfig/gconf-cfg] Error 1
  Makefile:567: recipe for target 'gconfig' failed
  make: *** [gconfig] Error 2
  $ git status
  HEAD detached at v5.4
  Untracked files:
    (use "git add <file>..." to include in what will be committed)

          scripts/kconfig/gconf-cfg.tmp

  nothing added to commit but untracked files present (use "git add" to track)

This is because the check scripts are run with filechk, which misses
to clean up the temporary file on failure.

When the line

  { $(filechk_$(1)); } > $@.tmp;

... fails, it exits immediately due to the 'set -e'. Use trap to make
sure to delete the temporary file on exit.

For extra safety, I replaced $@.tmp with $(dot-target).tmp to make it
a hidden file.

Reported-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/Kbuild.include | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 10ba926..d1dd4a6 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -55,14 +55,13 @@ kecho := $($(quiet)kecho)
 # - stdin is piped in from the first prerequisite ($<) so one has
 #   to specify a valid file as first prerequisite (often the kbuild file)
 define filechk
-	$(Q)set -e;				\
-	mkdir -p $(dir $@);			\
-	{ $(filechk_$(1)); } > $@.tmp;		\
-	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
-		rm -f $@.tmp;			\
-	else					\
-		$(kecho) '  UPD     $@';	\
-		mv -f $@.tmp $@;		\
+	$(Q)set -e;						\
+	mkdir -p $(dir $@);					\
+	trap "rm -f $(dot-target).tmp" EXIT;			\
+	{ $(filechk_$(1)); } > $(dot-target).tmp;		\
+	if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then	\
+		$(kecho) '  UPD     $@';			\
+		mv -f $(dot-target).tmp $@;			\
 	fi
 endef
 
-- 
2.7.4