btf_split.c

  1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright (c) 2020 Facebook */
  3#include <test_progs.h>
  4#include <bpf/btf.h>
  5
  6static char *dump_buf;
  7static size_t dump_buf_sz;
  8static FILE *dump_buf_file;
  9
 10static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
 11{
 12	vfprintf(ctx, fmt, args);
 13}
 14
 15/* Write raw BTF to file, return number of bytes written or negative errno */
 16static ssize_t btf_raw_write(struct btf *btf, char *file)
 17{
 18	ssize_t written = 0;
 19	const void *data;
 20	__u32 size = 0;
 21	int fd, ret;
 22
 23	fd = mkstemp(file);
 24	if (!ASSERT_GE(fd, 0, "create_file"))
 25		return -errno;
 26
 27	data = btf__raw_data(btf, &size);
 28	if (!ASSERT_OK_PTR(data, "btf__raw_data")) {
 29		close(fd);
 30		return -EINVAL;
 31	}
 32	while (written < size) {
 33		ret = write(fd, data + written, size - written);
 34		if (!ASSERT_GE(ret, 0, "write succeeded")) {
 35			close(fd);
 36			return -errno;
 37		}
 38		written += ret;
 39	}
 40	close(fd);
 41	return written;
 42}
 43
 44static void __test_btf_split(bool multi)
 45{
 46	char multisplit_btf_file[] = "/tmp/test_btf_multisplit.XXXXXX";
 47	char split_btf_file[] = "/tmp/test_btf_split.XXXXXX";
 48	char base_btf_file[] = "/tmp/test_btf_base.XXXXXX";
 49	ssize_t multisplit_btf_sz = 0, split_btf_sz = 0, base_btf_sz = 0;
 50	struct btf_dump *d = NULL;
 51	const struct btf_type *t, *ot;
 52	struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL;
 53	struct btf *btf4 = NULL, *btf5 = NULL, *btf6 = NULL;
 54	int str_off, i, err;
 55
 56	btf1 = btf__new_empty();
 57	if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
 58		return;
 59
 60	btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */
 61
 62	btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);	/* [1] int */
 63	btf__add_ptr(btf1, 1);				/* [2] ptr to int */
 64
 65	btf__add_struct(btf1, "s1", 4);			/* [3] struct s1 { */
 66	btf__add_field(btf1, "f1", 1, 0, 0);		/*      int f1; */
 67							/* } */
 68
 69	btf2 = btf__new_empty_split(btf1);
 70	if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
 71		goto cleanup;
 72
 73	/* pointer size should be "inherited" from main BTF */
 74	ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");
 75
 76	str_off = btf__find_str(btf2, "int");
 77	ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");
 78
 79	t = btf__type_by_id(btf2, 1);
 80	if (!ASSERT_OK_PTR(t, "int_type"))
 81		goto cleanup;
 82	ASSERT_EQ(btf_is_int(t), true, "int_kind");
 83	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");
 84
 85	btf__add_struct(btf2, "s2", 16);		/* [4] struct s2 {	*/
 86	btf__add_field(btf2, "f1", 3, 0, 0);		/*      struct s1 f1;	*/
 87	btf__add_field(btf2, "f2", 1, 32, 0);		/*      int f2;		*/
 88	btf__add_field(btf2, "f3", 2, 64, 0);		/*      int *f3;	*/
 89							/* } */
 90
 91	t = btf__type_by_id(btf1, 4);
 92	ASSERT_NULL(t, "split_type_in_main");
 93
 94	t = btf__type_by_id(btf2, 4);
 95	if (!ASSERT_OK_PTR(t, "split_struct_type"))
 96		goto cleanup;
 97	ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");
 98	ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");
 99	ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");
100
101	if (multi) {
102		btf3 = btf__new_empty_split(btf2);
103		if (!ASSERT_OK_PTR(btf3, "multi_split_btf"))
104			goto cleanup;
105	} else {
106		btf3 = btf2;
107	}
108
109	btf__add_union(btf3, "u1", 16);			/* [5] union u1 {	*/
110	btf__add_field(btf3, "f1", 4, 0, 0);		/*	struct s2 f1;	*/
111	btf__add_field(btf3, "uf2", 1, 0, 0);		/*	int f2;		*/
112							/* } */
113
114	if (multi) {
115		t = btf__type_by_id(btf2, 5);
116		ASSERT_NULL(t, "multisplit_type_in_first_split");
117	}
118
119	t = btf__type_by_id(btf3, 5);
120	if (!ASSERT_OK_PTR(t, "split_union_type"))
121		goto cleanup;
122	ASSERT_EQ(btf_is_union(t), true, "split_union_kind");
123	ASSERT_EQ(btf_vlen(t), 2, "split_union_vlen");
124	ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "u1", "split_union_name");
125	ASSERT_EQ(btf__type_cnt(btf3), 6, "split_type_cnt");
126
127	t = btf__type_by_id(btf3, 1);
128	if (!ASSERT_OK_PTR(t, "split_base_type"))
129		goto cleanup;
130	ASSERT_EQ(btf_is_int(t), true, "split_base_int");
131	ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "int", "split_base_type_name");
132
133	/* BTF-to-C dump of split BTF */
134	dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
135	if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
136		return;
137	d = btf_dump__new(btf3, btf_dump_printf, dump_buf_file, NULL);
138	if (!ASSERT_OK_PTR(d, "btf_dump__new"))
139		goto cleanup;
140	for (i = 1; i < btf__type_cnt(btf3); i++) {
141		err = btf_dump__dump_type(d, i);
142		ASSERT_OK(err, "dump_type_ok");
143	}
144	fflush(dump_buf_file);
145	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
146	ASSERT_STREQ(dump_buf,
147"struct s1 {\n"
148"	int f1;\n"
149"};\n\n"
150"struct s2 {\n"
151"	struct s1 f1;\n"
152"	int f2;\n"
153"	int *f3;\n"
154"};\n\n"
155"union u1 {\n"
156"	struct s2 f1;\n"
157"	int uf2;\n"
158"};\n\n", "c_dump");
159
160	/* write base, split BTFs to files and ensure parsing succeeds */
161	base_btf_sz = btf_raw_write(btf1, base_btf_file);
162	if (base_btf_sz < 0)
163		goto cleanup;
164	split_btf_sz = btf_raw_write(btf2, split_btf_file);
165	if (split_btf_sz < 0)
166		goto cleanup;
167	btf4 = btf__parse(base_btf_file, NULL);
168	if (!ASSERT_OK_PTR(btf4, "parse_base"))
169		goto cleanup;
170	btf5 = btf__parse_split(split_btf_file, btf4);
171	if (!ASSERT_OK_PTR(btf5, "parse_split"))
172		goto cleanup;
173	if (multi) {
174		multisplit_btf_sz = btf_raw_write(btf3, multisplit_btf_file);
175		if (multisplit_btf_sz < 0)
176			goto cleanup;
177		btf6 = btf__parse_split(multisplit_btf_file, btf5);
178		if (!ASSERT_OK_PTR(btf6, "parse_multisplit"))
179			goto cleanup;
180	} else {
181		btf6 = btf5;
182	}
183
184	if (!ASSERT_EQ(btf__type_cnt(btf3), btf__type_cnt(btf6), "cmp_type_cnt"))
185		goto cleanup;
186
187	/* compare parsed to original BTF */
188	for (i = 1; i < btf__type_cnt(btf6); i++) {
189		t = btf__type_by_id(btf6, i);
190		if (!ASSERT_OK_PTR(t, "type_in_parsed_btf"))
191			goto cleanup;
192		ot = btf__type_by_id(btf3, i);
193		if (!ASSERT_OK_PTR(ot, "type_in_orig_btf"))
194			goto cleanup;
195		if (!ASSERT_EQ(memcmp(t, ot, sizeof(*ot)), 0, "cmp_parsed_orig_btf"))
196			goto cleanup;
197	}
198
199cleanup:
200	if (dump_buf_file)
201		fclose(dump_buf_file);
202	free(dump_buf);
203	btf_dump__free(d);
204	btf__free(btf1);
205	btf__free(btf2);
206	if (btf2 != btf3)
207		btf__free(btf3);
208	btf__free(btf4);
209	btf__free(btf5);
210	if (btf5 != btf6)
211		btf__free(btf6);
212	if (base_btf_sz > 0)
213		unlink(base_btf_file);
214	if (split_btf_sz > 0)
215		unlink(split_btf_file);
216	if (multisplit_btf_sz > 0)
217		unlink(multisplit_btf_file);
218}
219
220void test_btf_split(void)
221{
222	if (test__start_subtest("single_split"))
223		__test_btf_split(false);
224	if (test__start_subtest("multi_split"))
225		__test_btf_split(true);
226}