Merge branch 'bpf-libbpf-cleanups'

Andrii Nakryiko says:

====================
This patch set's main goal is to teach bpf_object__open() (and its variants)
to automatically derive BPF program type/expected attach type from section
names, similarly to how bpf_prog_load() was doing it. This significantly
improves user experience by eliminating yet another
obvious-only-in-the-hindsight surprise, when using libbpf APIs.

There are a bunch of auxiliary clean-ups and improvements. E.g.,
bpf_program__get_type() and bpf_program__get_expected_attach_type() are added
for completeness and symmetry with corresponding setter APIs. Some clean up
and fixes in selftests/bpf are done as well.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/include/uapi/linux/if_link.h

@@ -167,6 +167,8 @@ enum {
 	IFLA_NEW_IFINDEX,
 	IFLA_MIN_MTU,
 	IFLA_MAX_MTU,
+	IFLA_PROP_LIST,
+	IFLA_ALT_IFNAME, /* Alternative ifname */
 	__IFLA_MAX
 };
 

tools/lib/bpf/libbpf.c

@@ -3611,6 +3611,7 @@ static struct bpf_object *
 __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
 		   struct bpf_object_open_opts *opts)
 {
+	struct bpf_program *prog;
 	struct bpf_object *obj;
 	const char *obj_name;
 	char tmp_name[64];
@@ -3650,8 +3651,24 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
 	CHECK_ERR(bpf_object__probe_caps(obj), err, out);
 	CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps), err, out);
 	CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
-
 	bpf_object__elf_finish(obj);
+
+	bpf_object__for_each_program(prog, obj) {
+		enum bpf_prog_type prog_type;
+		enum bpf_attach_type attach_type;
+
+		err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
+					       &attach_type);
+		if (err == -ESRCH)
+			/* couldn't guess, but user might manually specify */
+			continue;
+		if (err)
+			goto out;
+
+		bpf_program__set_type(prog, prog_type);
+		bpf_program__set_expected_attach_type(prog, attach_type);
+	}
+
 	return obj;
 out:
 	bpf_object__close(obj);
@@ -4463,6 +4480,11 @@ int bpf_program__nth_fd(const struct bpf_program *prog, int n)
 	return fd;
 }
 
+enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
+{
+	return prog->type;
+}
+
 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
 {
 	prog->type = type;
@@ -4497,6 +4519,12 @@ BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
+enum bpf_attach_type
+bpf_program__get_expected_attach_type(struct bpf_program *prog)
+{
+	return prog->expected_attach_type;
+}
+
 void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 					   enum bpf_attach_type type)
 {
@@ -4536,11 +4564,15 @@ static const struct {
 } section_names[] = {
 	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
 	BPF_PROG_SEC("kprobe/",			BPF_PROG_TYPE_KPROBE),
+	BPF_PROG_SEC("uprobe/",			BPF_PROG_TYPE_KPROBE),
 	BPF_PROG_SEC("kretprobe/",		BPF_PROG_TYPE_KPROBE),
+	BPF_PROG_SEC("uretprobe/",		BPF_PROG_TYPE_KPROBE),
 	BPF_PROG_SEC("classifier",		BPF_PROG_TYPE_SCHED_CLS),
 	BPF_PROG_SEC("action",			BPF_PROG_TYPE_SCHED_ACT),
 	BPF_PROG_SEC("tracepoint/",		BPF_PROG_TYPE_TRACEPOINT),
+	BPF_PROG_SEC("tp/",			BPF_PROG_TYPE_TRACEPOINT),
 	BPF_PROG_SEC("raw_tracepoint/",		BPF_PROG_TYPE_RAW_TRACEPOINT),
+	BPF_PROG_SEC("raw_tp/",			BPF_PROG_TYPE_RAW_TRACEPOINT),
 	BPF_PROG_BTF("tp_btf/",			BPF_PROG_TYPE_RAW_TRACEPOINT),
 	BPF_PROG_SEC("xdp",			BPF_PROG_TYPE_XDP),
 	BPF_PROG_SEC("perf_event",		BPF_PROG_TYPE_PERF_EVENT),
@@ -4676,7 +4708,7 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
 		free(type_names);
 	}
 
-	return -EINVAL;
+	return -ESRCH;
 }
 
 int libbpf_attach_type_by_name(const char *name,
@@ -4706,15 +4738,6 @@ int libbpf_attach_type_by_name(const char *name,
 	return -EINVAL;
 }
 
-static int
-bpf_program__identify_section(struct bpf_program *prog,
-			      enum bpf_prog_type *prog_type,
-			      enum bpf_attach_type *expected_attach_type)
-{
-	return libbpf_prog_type_by_name(prog->section_name, prog_type,
-					expected_attach_type);
-}
-
 int bpf_map__fd(const struct bpf_map *map)
 {
 	return map ? map->fd : -EINVAL;
@@ -4882,8 +4905,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
 {
 	struct bpf_object_open_attr open_attr = {};
 	struct bpf_program *prog, *first_prog = NULL;
-	enum bpf_attach_type expected_attach_type;
-	enum bpf_prog_type prog_type;
 	struct bpf_object *obj;
 	struct bpf_map *map;
 	int err;
@@ -4901,26 +4922,27 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
 		return -ENOENT;
 
 	bpf_object__for_each_program(prog, obj) {
+		enum bpf_attach_type attach_type = attr->expected_attach_type;
 		/*
-		 * If type is not specified, try to guess it based on
-		 * section name.
+		 * to preserve backwards compatibility, bpf_prog_load treats
+		 * attr->prog_type, if specified, as an override to whatever
+		 * bpf_object__open guessed
+		 */
+		if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
+			bpf_program__set_type(prog, attr->prog_type);
+			bpf_program__set_expected_attach_type(prog,
+							      attach_type);
+		}
+		if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
+			/*
+			 * we haven't guessed from section name and user
+			 * didn't provide a fallback type, too bad...
 			 */
-		prog_type = attr->prog_type;
-		prog->prog_ifindex = attr->ifindex;
-		expected_attach_type = attr->expected_attach_type;
-		if (prog_type == BPF_PROG_TYPE_UNSPEC) {
-			err = bpf_program__identify_section(prog, &prog_type,
-							    &expected_attach_type);
-			if (err < 0) {
 			bpf_object__close(obj);
 			return -EINVAL;
 		}
-		}
-
-		bpf_program__set_type(prog, prog_type);
-		bpf_program__set_expected_attach_type(prog,
-						      expected_attach_type);
 
+		prog->prog_ifindex = attr->ifindex;
 		prog->log_level = attr->log_level;
 		prog->prog_flags = attr->prog_flags;
 		if (!first_prog)

tools/lib/bpf/libbpf.h

@@ -302,8 +302,13 @@ LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog);
 LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog);
+
+LIBBPF_API enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog);
 LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
 				      enum bpf_prog_type type);
+
+LIBBPF_API enum bpf_attach_type
+bpf_program__get_expected_attach_type(struct bpf_program *prog);
 LIBBPF_API void
 bpf_program__set_expected_attach_type(struct bpf_program *prog,
 				      enum bpf_attach_type type);

tools/lib/bpf/libbpf.map

@@ -195,4 +195,6 @@ LIBBPF_0.0.6 {
 	global:
 		bpf_object__open_file;
 		bpf_object__open_mem;
+		bpf_program__get_expected_attach_type;
+		bpf_program__get_type;
 } LIBBPF_0.0.5;

tools/testing/selftests/bpf/prog_tests/attach_probe.c

@@ -99,11 +99,6 @@ void test_attach_probe(void)
 		  "prog '%s' not found\n", uretprobe_name))
 		goto cleanup;
 
-	bpf_program__set_kprobe(kprobe_prog);
-	bpf_program__set_kprobe(kretprobe_prog);
-	bpf_program__set_kprobe(uprobe_prog);
-	bpf_program__set_kprobe(uretprobe_prog);
-
 	/* create maps && load programs */
 	err = bpf_object__load(obj);
 	if (CHECK(err, "obj_load", "err %d\n", err))

tools/testing/selftests/bpf/prog_tests/core_reloc.c

@@ -391,7 +391,6 @@ void test_core_reloc(void)
 		if (CHECK(!prog, "find_probe",
 			  "prog '%s' not found\n", probe_name))
 			goto cleanup;
-		bpf_program__set_type(prog, BPF_PROG_TYPE_RAW_TRACEPOINT);
 
 		load_attr.obj = obj;
 		load_attr.log_level = 0;

tools/testing/selftests/bpf/prog_tests/rdonly_maps.c

@@ -36,10 +36,6 @@ void test_rdonly_maps(void)
 	if (CHECK(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
 		return;
 
-	bpf_object__for_each_program(prog, obj) {
-		bpf_program__set_raw_tracepoint(prog);
-	}
-
 	err = bpf_object__load(obj);
 	if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
 		goto cleanup;

tools/testing/selftests/bpf/prog_tests/reference_tracking.c

@@ -31,7 +31,8 @@ void test_reference_tracking(void)
 		if (strstr(title, ".text") != NULL)
 			continue;
 
-		bpf_program__set_type(prog, BPF_PROG_TYPE_SCHED_CLS);
+		if (!test__start_subtest(title))
+			continue;
 
 		/* Expect verifier failure if test name has 'fail' */
 		if (strstr(title, "fail") != NULL) {

tools/testing/selftests/bpf/progs/test_sk_lookup_kern.c

@@ -53,7 +53,7 @@ static struct bpf_sock_tuple *get_tuple(void *data, __u64 nh_off,
 	return result;
 }
 
-SEC("sk_lookup_success")
+SEC("classifier/sk_lookup_success")
 int bpf_sk_lookup_test0(struct __sk_buff *skb)
 {
 	void *data_end = (void *)(long)skb->data_end;
@@ -78,7 +78,7 @@ int bpf_sk_lookup_test0(struct __sk_buff *skb)
 	return sk ? TC_ACT_OK : TC_ACT_UNSPEC;
 }
 
-SEC("sk_lookup_success_simple")
+SEC("classifier/sk_lookup_success_simple")
 int bpf_sk_lookup_test1(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -90,7 +90,7 @@ int bpf_sk_lookup_test1(struct __sk_buff *skb)
 	return 0;
 }
 
-SEC("fail_use_after_free")
+SEC("classifier/fail_use_after_free")
 int bpf_sk_lookup_uaf(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -105,7 +105,7 @@ int bpf_sk_lookup_uaf(struct __sk_buff *skb)
 	return family;
 }
 
-SEC("fail_modify_sk_pointer")
+SEC("classifier/fail_modify_sk_pointer")
 int bpf_sk_lookup_modptr(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -120,7 +120,7 @@ int bpf_sk_lookup_modptr(struct __sk_buff *skb)
 	return 0;
 }
 
-SEC("fail_modify_sk_or_null_pointer")
+SEC("classifier/fail_modify_sk_or_null_pointer")
 int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -134,7 +134,7 @@ int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
 	return 0;
 }
 
-SEC("fail_no_release")
+SEC("classifier/fail_no_release")
 int bpf_sk_lookup_test2(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -143,7 +143,7 @@ int bpf_sk_lookup_test2(struct __sk_buff *skb)
 	return 0;
 }
 
-SEC("fail_release_twice")
+SEC("classifier/fail_release_twice")
 int bpf_sk_lookup_test3(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -155,7 +155,7 @@ int bpf_sk_lookup_test3(struct __sk_buff *skb)
 	return 0;
 }
 
-SEC("fail_release_unchecked")
+SEC("classifier/fail_release_unchecked")
 int bpf_sk_lookup_test4(struct __sk_buff *skb)
 {
 	struct bpf_sock_tuple tuple = {};
@@ -172,7 +172,7 @@ void lookup_no_release(struct __sk_buff *skb)
 	bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
 }
 
-SEC("fail_no_release_subcall")
+SEC("classifier/fail_no_release_subcall")
 int bpf_sk_lookup_test5(struct __sk_buff *skb)
 {
 	lookup_no_release(skb);

tools/testing/selftests/bpf/test_maps.c

@@ -1142,7 +1142,6 @@ static void test_sockmap(unsigned int tasks, void *data)
 #define MAPINMAP_PROG "./test_map_in_map.o"
 static void test_map_in_map(void)
 {
-	struct bpf_program *prog;
 	struct bpf_object *obj;
 	struct bpf_map *map;
 	int mim_fd, fd, err;
@@ -1179,9 +1178,6 @@ static void test_map_in_map(void)
 		goto out_map_in_map;
 	}
 
-	bpf_object__for_each_program(prog, obj) {
-		bpf_program__set_xdp(prog);
-	}
 	bpf_object__load(obj);
 
 	map = bpf_object__find_map_by_name(obj, "mim_array");

tools/testing/selftests/bpf/test_progs.c

@@ -20,7 +20,7 @@ struct prog_test_def {
 	bool tested;
 	bool need_cgroup_cleanup;
 
-	const char *subtest_name;
+	char *subtest_name;
 	int subtest_num;
 
 	/* store counts before subtest started */
@@ -81,16 +81,17 @@ void test__end_subtest()
 	fprintf(env.stdout, "#%d/%d %s:%s\n",
 	       test->test_num, test->subtest_num,
 	       test->subtest_name, sub_error_cnt ? "FAIL" : "OK");
+
+	free(test->subtest_name);
+	test->subtest_name = NULL;
 }
 
 bool test__start_subtest(const char *name)
 {
 	struct prog_test_def *test = env.test;
 
-	if (test->subtest_name) {
+	if (test->subtest_name)
 		test__end_subtest();
-		test->subtest_name = NULL;
-	}
 
 	test->subtest_num++;
 
@@ -104,7 +105,13 @@ bool test__start_subtest(const char *name)
 	if (!should_run(&env.subtest_selector, test->subtest_num, name))
 		return false;
 
-	test->subtest_name = name;
+	test->subtest_name = strdup(name);
+	if (!test->subtest_name) {
+		fprintf(env.stderr,
+			"Subtest #%d: failed to copy subtest name!\n",
+			test->subtest_num);
+		return false;
+	}
 	env.test->old_error_cnt = env.test->error_cnt;
 
 	return true;