selftests: Introduce Makefile variable to list shared bash scripts

Some tests written in bash source other files in a parent directory. For
example, drivers/net/bonding/dev_addr_lists.sh sources
net/forwarding/lib.sh. If a subset of tests is exported and run outside the
source tree (for example by using `make -C tools/testing/selftests gen_tar
TARGETS="drivers/net/bonding"`), these other files must be made available
as well.

Commit ae108c48b5d2 ("selftests: net: Fix cross-tree inclusion of scripts")
addressed this problem by symlinking and copying the sourced files but this
only works for direct dependencies. Commit 25ae948b4478 ("selftests/net:
add lib.sh") changed net/forwarding/lib.sh to source net/lib.sh. As a
result, that latter file must be included as well when the former is
exported. This was not handled and was reverted in commit 2114e83381d3
("selftests: forwarding: Avoid failures to source net/lib.sh"). In order to
allow reinstating the inclusion of net/lib.sh from net/forwarding/lib.sh,
add a mechanism to list dependent files in a new Makefile variable and
export them. This allows sourcing those files using the same expression
whether tests are run in-tree or exported.

Dependencies are not resolved recursively so transitive dependencies must
be listed in TEST_INCLUDES. For example, if net/forwarding/lib.sh sources
net/lib.sh; the Makefile related to a test that sources
net/forwarding/lib.sh from a parent directory must list:
TEST_INCLUDES := \
	../../../net/forwarding/lib.sh \
	../../../net/lib.sh

v2:
Fix rst syntax in Documentation/dev-tools/kselftest.rst (Jakub Kicinski)

v1 (from RFC):
* changed TEST_INCLUDES to take relative paths, like other TEST_* variables
  (Vladimir Oltean)
* preserved common "$(MAKE) OUTPUT=... -C ... target" ordering in Makefile
  (Petr Machata)

Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index aa646e0661f3..087fee22dd53 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -69,11 +69,29 @@ define RUN_TESTS
 	run_many $(1)
 endef
 
+define INSTALL_INCLUDES
+	$(if $(TEST_INCLUDES), \
+		relative_files=""; \
+		for entry in $(TEST_INCLUDES); do \
+			entry_dir=$$(readlink -e "$$(dirname "$$entry")"); \
+			entry_name=$$(basename "$$entry"); \
+			relative_dir=$${entry_dir#"$$SRC_PATH"/}; \
+			if [ "$$relative_dir" = "$$entry_dir" ]; then \
+				echo "Error: TEST_INCLUDES entry \"$$entry\" not located inside selftests directory ($$SRC_PATH)" >&2; \
+				exit 1; \
+			fi; \
+			relative_files="$$relative_files $$relative_dir/$$entry_name"; \
+		done; \
+		cd $(SRC_PATH) && rsync -aR $$relative_files $(OBJ_PATH)/ \
+	)
+endef
+
 run_tests: all
 ifdef building_out_of_srctree
 	@if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)" != "X" ]; then \
 		rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT); \
 	fi
+	@$(INSTALL_INCLUDES)
 	@if [ "X$(TEST_PROGS)" != "X" ]; then \
 		$(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) \
 				  $(addprefix $(OUTPUT)/,$(TEST_PROGS))) ; \
@@ -103,6 +121,7 @@ endef
 install: all
 ifdef INSTALL_PATH
 	$(INSTALL_RULE)
+	$(INSTALL_INCLUDES)
 else
 	$(error Error: set INSTALL_PATH to use install)
 endif