Merge branch 'libbpf-api'

Andrii Nakryiko says:

====================
Add bpf_object__open_file() and bpf_object__open_mem() APIs that use a new
approach to providing future-proof non-ABI-breaking API changes. It relies on
APIs accepting optional self-describing "opts" struct, containing its own
size, filled out and provided by potentially outdated (as well as
newer-than-libbpf) user application. A set of internal helper macros
(OPTS_VALID, OPTS_HAS, and OPTS_GET) streamline and simplify a graceful
handling forward and backward compatibility for user applications dynamically
linked against different versions of libbpf shared library.

Users of libbpf are provided with convenience macro LIBBPF_OPTS that takes
care of populating correct structure size and zero-initializes options struct,
which helps avoid obscure issues of unitialized padding. Uninitialized padding
in a struct might turn into garbage-populated new fields understood by future
versions of libbpf.

Patch #1 removes enforcement of kern_version in libbpf and always populates
correct one on behalf of users.
Patch #2 defines necessary infrastructure for options and two new open APIs
relying on it.
Patch #3 fixes bug in bpf_object__name().
Patch #4 switches two of test_progs' tests to use new APIs as a validation
that they work as expected.

v2->v3:
- fix LIBBPF_OPTS() to ensure zero-initialization of padded bytes;
- pass through name override and relaxed maps flag for open_file() (Toke);
- fix bpf_object__name() to actually return object name;
- don't bother parsing and verifying version section (John);

v1->v2:
- use better approach for tracking last field in opts struct;
- convert few tests to new APIs for validation;
- fix bug with using offsetof(last_field) instead of offsetofend(last_field).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 14 insertions, 2 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/reference_tracking.c b/tools/testing/selftests/bpf/prog_tests/reference_tracking.c
index 5c78e2b5a917..86cee820d4d3 100644
--- a/tools/testing/selftests/bpf/prog_tests/reference_tracking.c
+++ b/tools/testing/selftests/bpf/prog_tests/reference_tracking.c
@@ -3,16 +3,26 @@
 
 void test_reference_tracking(void)
 {
-	const char *file = "./test_sk_lookup_kern.o";
+	const char *file = "test_sk_lookup_kern.o";
+	const char *obj_name = "ref_track";
+	LIBBPF_OPTS(bpf_object_open_opts, open_opts,
+		.object_name = obj_name,
+		.relaxed_maps = true,
+	);
 	struct bpf_object *obj;
 	struct bpf_program *prog;
 	__u32 duration = 0;
 	int err = 0;
 
-	obj = bpf_object__open(file);
+	obj = bpf_object__open_file(file, &open_opts);
 	if (CHECK_FAIL(IS_ERR(obj)))
 		return;
 
+	if (CHECK(strcmp(bpf_object__name(obj), obj_name), "obj_name",
+		  "wrong obj name '%s', expected '%s'\n",
+		  bpf_object__name(obj), obj_name))
+		goto cleanup;
+
 	bpf_object__for_each_program(prog, obj) {
 		const char *title;
 
@@ -35,5 +45,7 @@ void test_reference_tracking(void)
 		}
 		CHECK(err, title, "\n");
 	}
+
+cleanup:
 	bpf_object__close(obj);
 }