On 3/4/20 7:20 PM, Kees Cook wrote:
On Wed, Mar 04, 2020 at 05:36:27PM -0700, Shuah Khan wrote:
Fix seccomp relocatable builds. This is a simple fix to use the
right lib.mk variable TEST_CUSTOM_PROGS to continue to do custom
build to preserve dependency on kselftest_harness.h local header.
This change applies cutom rule to seccomp_bpf seccomp_benchmark
for a simpler logic.
Uses $(OUTPUT) defined in lib.mk to handle build relocation.
The following use-cases work with this change:
In seccomp directory:
make all and make clean
This works.
From top level from main Makefile:
make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
This fails for me:
$ make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
make[1]: Entering directory '/home/kees/src/linux/objdir'
make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
ARCH=arm64 -C ../../.. headers_install
make[4]: ../scripts/Makefile.build: No such file or directory
make[4]: *** No rule to make target '../scripts/Makefile.build'. Stop.
make[3]: *** [Makefile:501: scripts_basic] Error 2
make[2]: *** [Makefile:151: khdr] Error 2
make[1]: *** [/home/kees/src/linux/Makefile:1221: kselftest-install] Error 2
make[1]: Leaving directory '/home/kees/src/linux/objdir'
make: *** [Makefile:180: sub-make] Error 2
(My "objdir" is empty)
If I remove O=objdir everything is fine. And see below...
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/seccomp/Makefile | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index 1760b3e39730..355bcbc0394a 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -1,17 +1,16 @@
# SPDX-License-Identifier: GPL-2.0
-all:
-
-include ../lib.mk
+CFLAGS += -Wl,-no-as-needed -Wall
+LDFLAGS += -lpthread
.PHONY: all clean
-BINARIES := seccomp_bpf seccomp_benchmark
-CFLAGS += -Wl,-no-as-needed -Wall
+include ../lib.mk
+
+# OUTPUT set by lib.mk
+TEST_CUSTOM_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
-seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
- $(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
+$(TEST_CUSTOM_PROGS): ../kselftest_harness.h
-TEST_PROGS += $(BINARIES)
-EXTRA_CLEAN := $(BINARIES)
+all: $(TEST_CUSTOM_PROGS)
-all: $(BINARIES)
+EXTRA_CLEAN := $(TEST_CUSTOM_PROGS)
--
2.20.1
Instead of the TEST_CUSTOM_PROGS+all dance, you can just add an explicit
dependency, with the final seccomp/Makefile looking like this:
# SPDX-License-Identifier: GPL-2.0
CFLAGS += -Wl,-no-as-needed -Wall
LDFLAGS += -lpthread
TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
TEST_CUSTOM_PROGS is for differentiating test programs that
can't use lib.mk generic rules. It is appropriate to use
for seccomp_bpf
include ../lib.mk
# Additional dependencies
$(OUTPUT)/seccomp_bpf: ../kselftest_harness.h
(Though this fails in the same way as above when run from the top-level
directory.)
I didn't see this because I have been the same directory I used
for relocated cross-build kernel. :(
Thanks for testing this. I know the problem here. all is a dependency
for install step and $(OUTPUT) is referencing the objdir before it
gets created. It is a Makefile/lib.mk problem to fix.
I will do a separate patch for this. This will show up in any test
that is using $(OUTPUT) to relocate objects mainly the ones that
require custom build rule like seeccomp.
thanks,
-- Shuah
