selftests/bpf: Add split BTF basic test

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include <test_progs.h>

#include <bpf/btf.h>

static char *dump_buf;

static size_t dump_buf_sz;

static FILE *dump_buf_file;

static void btf_dump_printf(void *ctx, const char *fmt, va_list args)

{

	vfprintf(ctx, fmt, args);

}

void test_btf_split() {

	struct btf_dump_opts opts;

	struct btf_dump *d = NULL;

	const struct btf_type *t;

	struct btf *btf1, *btf2;

	int str_off, i, err;

	btf1 = btf__new_empty();

	if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))

		return;

	btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */

	btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);	/* [1] int */

	btf__add_ptr(btf1, 1);				/* [2] ptr to int */

	btf__add_struct(btf1, "s1", 4);			/* [3] struct s1 { */

	btf__add_field(btf1, "f1", 1, 0, 0);		/*      int f1; */

							/* } */

	btf2 = btf__new_empty_split(btf1);

	if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))

		goto cleanup;

	/* pointer size should be "inherited" from main BTF */

	ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");

	str_off = btf__find_str(btf2, "int");

	ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");

	t = btf__type_by_id(btf2, 1);

	if (!ASSERT_OK_PTR(t, "int_type"))

		goto cleanup;

	ASSERT_EQ(btf_is_int(t), true, "int_kind");

	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");

	btf__add_struct(btf2, "s2", 16);		/* [4] struct s2 {	*/

	btf__add_field(btf2, "f1", 3, 0, 0);		/*      struct s1 f1;	*/

	btf__add_field(btf2, "f2", 1, 32, 0);		/*      int f2;		*/

	btf__add_field(btf2, "f3", 2, 64, 0);		/*      int *f3;	*/

							/* } */

	t = btf__type_by_id(btf1, 4);

	ASSERT_NULL(t, "split_type_in_main");

	t = btf__type_by_id(btf2, 4);

	if (!ASSERT_OK_PTR(t, "split_struct_type"))

		goto cleanup;

	ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");

	ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");

	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");

	/* BTF-to-C dump of split BTF */

	dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);

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

		return;

	opts.ctx = dump_buf_file;

	d = btf_dump__new(btf2, NULL, &opts, btf_dump_printf);

	if (!ASSERT_OK_PTR(d, "btf_dump__new"))

		goto cleanup;

	for (i = 1; i <= btf__get_nr_types(btf2); 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,

"struct s1 {\n"

"	int f1;\n"

"};\n"

"\n"

"struct s2 {\n"

"	struct s1 f1;\n"

"	int f2;\n"

"	int *f3;\n"

"};\n\n", "c_dump");

cleanup:

	if (dump_buf_file)

		fclose(dump_buf_file);

	free(dump_buf);

	btf_dump__free(d);

	btf__free(btf1);

	btf__free(btf2);

}

	___ok;								\

})

#define ASSERT_NEQ(actual, expected, name) ({				\

	static int duration = 0;					\

	typeof(actual) ___act = (actual);				\

	typeof(expected) ___exp = (expected);				\

	bool ___ok = ___act != ___exp;					\

	CHECK(!___ok, (name),						\

	      "unexpected %s: actual %lld == expected %lld\n",		\

	      (name), (long long)(___act), (long long)(___exp));	\

	___ok;								\

})

#define ASSERT_STREQ(actual, expected, name) ({				\

	static int duration = 0;					\

	const char *___act = actual;					\