[PATCH] kbuild: set EXIT trap before creating temporary directory

From: Masahiro Yamada
Date: Wed Jul 27 2022 - 23:17:57 EST


Swap the order of 'mkdir' and 'trap' just in case the subshell is
interrupted between 'mkdir' and 'trap' although the effect might be
subtle.

Please not this is not a perfect solution to avoid the left-over tmp
directory. There are more cases that miss to remove the tmp directory,
for example:

- When interrupted, dash does not invoke the EXIT trap (bash does)

- 'rm' command might be interrupted before removing the directory

I am not addressing all the cases since the tmp directory is harmless
after all.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

scripts/Kconfig.include | 2 +-
scripts/Makefile.compiler | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index c1f4222d223d..a0ccceb22cf8 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -25,7 +25,7 @@ failure = $(if-success,$(1),n,y)

# $(cc-option,<flag>)
# Return y if the compiler supports <flag>, n otherwise
-cc-option = $(success,mkdir .tmp_$$; trap "rm -rf .tmp_$$" EXIT; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$/tmp.o)
+cc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(CC) -Werror $(CLANG_FLAGS) $(1) -c -x c /dev/null -o .tmp_$$/tmp.o)

# $(ld-option,<flag>)
# Return y if the linker supports <flag>, n otherwise
diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
index 86ecd2ac874c..94d0d40cddb3 100644
--- a/scripts/Makefile.compiler
+++ b/scripts/Makefile.compiler
@@ -21,8 +21,8 @@ TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
# automatically cleaned up.
try-run = $(shell set -e; \
TMP=$(TMPOUT)/tmp; \
- mkdir -p $(TMPOUT); \
trap "rm -rf $(TMPOUT)" EXIT; \
+ mkdir -p $(TMPOUT); \
if ($(1)) >/dev/null 2>&1; \
then echo "$(2)"; \
else echo "$(3)"; \
--
2.34.1