xref: /linux/tools/testing/selftests/bpf/prog_tests/btf_split.c (revision 90b83efa6701656e02c86e7df2cb1765ea602d07)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Facebook */
3 #include <test_progs.h>
4 #include <bpf/btf.h>
5 
6 static char *dump_buf;
7 static size_t dump_buf_sz;
8 static FILE *dump_buf_file;
9 
10 static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
11 {
12 	vfprintf(ctx, fmt, args);
13 }
14 
15 static void __test_btf_split(bool multi)
16 {
17 	struct btf_dump *d = NULL;
18 	const struct btf_type *t;
19 	struct btf *btf1, *btf2, *btf3 = NULL;
20 	int str_off, i, err;
21 
22 	btf1 = btf__new_empty();
23 	if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
24 		return;
25 
26 	btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */
27 
28 	btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);	/* [1] int */
29 	btf__add_ptr(btf1, 1);				/* [2] ptr to int */
30 
31 	btf__add_struct(btf1, "s1", 4);			/* [3] struct s1 { */
32 	btf__add_field(btf1, "f1", 1, 0, 0);		/*      int f1; */
33 							/* } */
34 
35 	btf2 = btf__new_empty_split(btf1);
36 	if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
37 		goto cleanup;
38 
39 	/* pointer size should be "inherited" from main BTF */
40 	ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");
41 
42 	str_off = btf__find_str(btf2, "int");
43 	ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");
44 
45 	t = btf__type_by_id(btf2, 1);
46 	if (!ASSERT_OK_PTR(t, "int_type"))
47 		goto cleanup;
48 	ASSERT_EQ(btf_is_int(t), true, "int_kind");
49 	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");
50 
51 	btf__add_struct(btf2, "s2", 16);		/* [4] struct s2 {	*/
52 	btf__add_field(btf2, "f1", 3, 0, 0);		/*      struct s1 f1;	*/
53 	btf__add_field(btf2, "f2", 1, 32, 0);		/*      int f2;		*/
54 	btf__add_field(btf2, "f3", 2, 64, 0);		/*      int *f3;	*/
55 							/* } */
56 
57 	t = btf__type_by_id(btf1, 4);
58 	ASSERT_NULL(t, "split_type_in_main");
59 
60 	t = btf__type_by_id(btf2, 4);
61 	if (!ASSERT_OK_PTR(t, "split_struct_type"))
62 		goto cleanup;
63 	ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");
64 	ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");
65 	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");
66 
67 	if (multi) {
68 		btf3 = btf__new_empty_split(btf2);
69 		if (!ASSERT_OK_PTR(btf3, "multi_split_btf"))
70 			goto cleanup;
71 	} else {
72 		btf3 = btf2;
73 	}
74 
75 	btf__add_union(btf3, "u1", 16);			/* [5] union u1 {	*/
76 	btf__add_field(btf3, "f1", 4, 0, 0);		/*	struct s2 f1;	*/
77 	btf__add_field(btf3, "uf2", 1, 0, 0);		/*	int f2;		*/
78 							/* } */
79 
80 	if (multi) {
81 		t = btf__type_by_id(btf2, 5);
82 		ASSERT_NULL(t, "multisplit_type_in_first_split");
83 	}
84 
85 	t = btf__type_by_id(btf3, 5);
86 	if (!ASSERT_OK_PTR(t, "split_union_type"))
87 		goto cleanup;
88 	ASSERT_EQ(btf_is_union(t), true, "split_union_kind");
89 	ASSERT_EQ(btf_vlen(t), 2, "split_union_vlen");
90 	ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "u1", "split_union_name");
91 	ASSERT_EQ(btf__type_cnt(btf3), 6, "split_type_cnt");
92 
93 	t = btf__type_by_id(btf3, 1);
94 	if (!ASSERT_OK_PTR(t, "split_base_type"))
95 		goto cleanup;
96 	ASSERT_EQ(btf_is_int(t), true, "split_base_int");
97 	ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "int", "split_base_type_name");
98 
99 	/* BTF-to-C dump of split BTF */
100 	dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
101 	if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
102 		return;
103 	d = btf_dump__new(btf3, btf_dump_printf, dump_buf_file, NULL);
104 	if (!ASSERT_OK_PTR(d, "btf_dump__new"))
105 		goto cleanup;
106 	for (i = 1; i < btf__type_cnt(btf3); i++) {
107 		err = btf_dump__dump_type(d, i);
108 		ASSERT_OK(err, "dump_type_ok");
109 	}
110 	fflush(dump_buf_file);
111 	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
112 	ASSERT_STREQ(dump_buf,
113 "struct s1 {\n"
114 "	int f1;\n"
115 "};\n\n"
116 "struct s2 {\n"
117 "	struct s1 f1;\n"
118 "	int f2;\n"
119 "	int *f3;\n"
120 "};\n\n"
121 "union u1 {\n"
122 "	struct s2 f1;\n"
123 "	int uf2;\n"
124 "};\n\n", "c_dump");
125 
126 cleanup:
127 	if (dump_buf_file)
128 		fclose(dump_buf_file);
129 	free(dump_buf);
130 	btf_dump__free(d);
131 	btf__free(btf1);
132 	btf__free(btf2);
133 	if (btf2 != btf3)
134 		btf__free(btf3);
135 }
136 
137 void test_btf_split(void)
138 {
139 	if (test__start_subtest("single_split"))
140 		__test_btf_split(false);
141 	if (test__start_subtest("multi_split"))
142 		__test_btf_split(true);
143 }
144