Commit 6c2d2a05 authored by Ihor Solodrai's avatar Ihor Solodrai Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add a btf_dump test for type_tags 



Factor out common routines handling custom BTF from
test_btf_dump_incremental. Then use them in the
test_btf_dump_type_tags.

test_btf_dump_type_tags verifies that a type tag is dumped correctly
with respect to its kflag.

Signed-off-by: default avatarIhor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20250130201239.1429648-5-ihor.solodrai@linux.dev
parent 2019c583

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

+110 −37
Original line number Diff line number Diff line
@@ -126,26 +126,69 @@ static int test_btf_dump_case(int n, struct btf_dump_test_case *t) 
	return err;

}



static char *dump_buf;

static size_t dump_buf_sz;

static FILE *dump_buf_file;

struct test_ctx {

	struct btf *btf;

	struct btf_dump *d;

	char *dump_buf;

	size_t dump_buf_sz;

	FILE *dump_buf_file;

};



static void test_btf_dump_incremental(void)

static void test_ctx__free(struct test_ctx *t)

{

	struct btf *btf = NULL;

	struct btf_dump *d = NULL;

	int id, err, i;

	fclose(t->dump_buf_file);

	free(t->dump_buf);

	btf_dump__free(t->d);

	btf__free(t->btf);

}



	dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);

	if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))

		return;

	btf = btf__new_empty();

	if (!ASSERT_OK_PTR(btf, "new_empty"))

static int test_ctx__init(struct test_ctx *t)

{

	t->dump_buf_file = open_memstream(&t->dump_buf, &t->dump_buf_sz);

	if (!ASSERT_OK_PTR(t->dump_buf_file, "dump_memstream"))

		return -1;

	t->btf = btf__new_empty();

	if (!ASSERT_OK_PTR(t->btf, "new_empty"))

		goto err_out;

	d = btf_dump__new(btf, btf_dump_printf, dump_buf_file, NULL);

	if (!ASSERT_OK(libbpf_get_error(d), "btf_dump__new"))

	t->d = btf_dump__new(t->btf, btf_dump_printf, t->dump_buf_file, NULL);

	if (!ASSERT_OK(libbpf_get_error(t->d), "btf_dump__new"))

		goto err_out;



	return 0;



err_out:

	test_ctx__free(t);

	return -1;

}



static void test_ctx__dump_and_compare(struct test_ctx *t,

				       const char *expected_output,

				       const char *message)

{

	int i, err;



	for (i = 1; i < btf__type_cnt(t->btf); i++) {

		err = btf_dump__dump_type(t->d, i);

		ASSERT_OK(err, "dump_type_ok");

	}



	fflush(t->dump_buf_file);

	t->dump_buf[t->dump_buf_sz] = 0; /* some libc implementations don't do this */



	ASSERT_STREQ(t->dump_buf, expected_output, message);

}



static void test_btf_dump_incremental(void)

{

	struct test_ctx t = {};

	struct btf *btf;

	int id, err;



	if (test_ctx__init(&t))

		return;



	btf = t.btf;



	/* First, generate BTF corresponding to the following C code:

	 *

	 * enum x;
@@ -182,15 +225,7 @@ static void test_btf_dump_incremental(void) 
	err = btf__add_field(btf, "x", 4, 0, 0);

	ASSERT_OK(err, "field_ok");



	for (i = 1; i < btf__type_cnt(btf); i++) {

		err = btf_dump__dump_type(d, i);

		ASSERT_OK(err, "dump_type_ok");

	}



	fflush(dump_buf_file);

	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */



	ASSERT_STREQ(dump_buf,

	test_ctx__dump_and_compare(&t,

"enum x;\n"

"\n"

"enum x {\n"
@@ -221,7 +256,7 @@ static void test_btf_dump_incremental(void) 
	 * enum values don't conflict;

	 *

	 */

	fseek(dump_buf_file, 0, SEEK_SET);

	fseek(t.dump_buf_file, 0, SEEK_SET);



	id = btf__add_struct(btf, "s", 4);

	ASSERT_EQ(id, 7, "struct_id");
@@ -232,14 +267,7 @@ static void test_btf_dump_incremental(void) 
	err = btf__add_field(btf, "s", 6, 64, 0);

	ASSERT_OK(err, "field_ok");



	for (i = 1; i < btf__type_cnt(btf); i++) {

		err = btf_dump__dump_type(d, i);

		ASSERT_OK(err, "dump_type_ok");

	}



	fflush(dump_buf_file);

	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */

	ASSERT_STREQ(dump_buf,

	test_ctx__dump_and_compare(&t,

"struct s___2 {\n"

"	enum x x;\n"

"	enum {\n"
@@ -248,11 +276,53 @@ static void test_btf_dump_incremental(void) 
"	struct s s;\n"

"};\n\n" , "c_dump1");



err_out:

	fclose(dump_buf_file);

	free(dump_buf);

	btf_dump__free(d);

	btf__free(btf);

	test_ctx__free(&t);

}



static void test_btf_dump_type_tags(void)

{

	struct test_ctx t = {};

	struct btf *btf;

	int id, err;



	if (test_ctx__init(&t))

		return;



	btf = t.btf;



	/* Generate BTF corresponding to the following C code:

	 *

	 * struct s {

	 *   void __attribute__((btf_type_tag(\"void_tag\"))) *p1;

	 *   void __attribute__((void_attr)) *p2;

	 * };

	 *

	 */



	id = btf__add_type_tag(btf, "void_tag", 0);

	ASSERT_EQ(id, 1, "type_tag_id");

	id = btf__add_ptr(btf, id);

	ASSERT_EQ(id, 2, "void_ptr_id1");



	id = btf__add_type_attr(btf, "void_attr", 0);

	ASSERT_EQ(id, 3, "type_attr_id");

	id = btf__add_ptr(btf, id);

	ASSERT_EQ(id, 4, "void_ptr_id2");



	id = btf__add_struct(btf, "s", 8);

	ASSERT_EQ(id, 5, "struct_id");

	err = btf__add_field(btf, "p1", 2, 0, 0);

	ASSERT_OK(err, "field_ok1");

	err = btf__add_field(btf, "p2", 4, 0, 0);

	ASSERT_OK(err, "field_ok2");



	test_ctx__dump_and_compare(&t,

"struct s {\n"

"	void __attribute__((btf_type_tag(\"void_tag\"))) *p1;\n"

"	void __attribute__((void_attr)) *p2;\n"

"};\n\n", "dump_and_compare");



	test_ctx__free(&t);

}



#define STRSIZE				4096
@@ -874,6 +944,9 @@ void test_btf_dump() { 
	if (test__start_subtest("btf_dump: incremental"))

		test_btf_dump_incremental();



	if (test__start_subtest("btf_dump: type_tags"))

		test_btf_dump_type_tags();



	btf = libbpf_find_kernel_btf();

	if (!ASSERT_OK_PTR(btf, "no kernel BTF found"))

		return;