selftests: Keep symlinks, when possible

When kselftest is built/installed with the 'gen_tar' target, rsync is
used for the installation step to copy files. Extra care is needed for
tests that have symlinks. Commit ae108c4 ("selftests: net: Fix
cross-tree inclusion of scripts") added '-L' (transform symlink into
referent file/dir) to rsync, to fix dangling links. However, that
broke some tests where the symlink (being a symlink) is part of the
test (e.g. exec:execveat).

Use rsync's '--copy-unsafe-links' that does right thing.

Fixes: ae108c4 ("selftests: net: Fix cross-tree inclusion of scripts")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Author: bjorn-rivos

tools/testing/selftests/lib.mk

@@ -106,7 +106,7 @@ endef
 run_tests: all
 ifdef building_out_of_srctree
 	@if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)" != "X" ]; then \
-		rsync -aLq $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT); \
+		rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT); \
 	fi
 	@if [ "X$(TEST_PROGS)" != "X" ]; then \
 		$(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) \
@@ -120,7 +120,7 @@ endif
 
 define INSTALL_SINGLE_RULE
 	$(if $(INSTALL_LIST),@mkdir -p $(INSTALL_PATH))
-	$(if $(INSTALL_LIST),rsync -aL $(INSTALL_LIST) $(INSTALL_PATH)/)
+	$(if $(INSTALL_LIST),rsync -a --copy-unsafe-links $(INSTALL_LIST) $(INSTALL_PATH)/)
 endef
 
 define INSTALL_RULE