1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2020 Facebook */
3#define _GNU_SOURCE
4#include <string.h>
5#include <byteswap.h>
6#include <test_progs.h>
7#include <bpf/btf.h>
8
9void test_btf_endian() {
10#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
11	enum btf_endianness endian = BTF_LITTLE_ENDIAN;
12#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
13	enum btf_endianness endian = BTF_BIG_ENDIAN;
14#else
15#error "Unrecognized __BYTE_ORDER__"
16#endif
17	enum btf_endianness swap_endian = 1 - endian;
18	struct btf *btf = NULL, *swap_btf = NULL;
19	const void *raw_data, *swap_raw_data;
20	const struct btf_type *t;
21	const struct btf_header *hdr;
22	__u32 raw_sz, swap_raw_sz;
23	int var_id;
24
25	/* Load BTF in native endianness */
26	btf = btf__parse_elf("btf_dump_test_case_syntax.bpf.o", NULL);
27	if (!ASSERT_OK_PTR(btf, "parse_native_btf"))
28		goto err_out;
29
30	ASSERT_EQ(btf__endianness(btf), endian, "endian");
31	btf__set_endianness(btf, swap_endian);
32	ASSERT_EQ(btf__endianness(btf), swap_endian, "endian");
33
34	/* Get raw BTF data in non-native endianness... */
35	raw_data = btf__raw_data(btf, &raw_sz);
36	if (!ASSERT_OK_PTR(raw_data, "raw_data_inverted"))
37		goto err_out;
38
39	/* ...and open it as a new BTF instance */
40	swap_btf = btf__new(raw_data, raw_sz);
41	if (!ASSERT_OK_PTR(swap_btf, "parse_swap_btf"))
42		goto err_out;
43
44	ASSERT_EQ(btf__endianness(swap_btf), swap_endian, "endian");
45	ASSERT_EQ(btf__type_cnt(swap_btf), btf__type_cnt(btf), "nr_types");
46
47	swap_raw_data = btf__raw_data(swap_btf, &swap_raw_sz);
48	if (!ASSERT_OK_PTR(swap_raw_data, "swap_raw_data"))
49		goto err_out;
50
51	/* both raw data should be identical (with non-native endianness) */
52	ASSERT_OK(memcmp(raw_data, swap_raw_data, raw_sz), "mem_identical");
53
54	/* make sure that at least BTF header data is really swapped */
55	hdr = swap_raw_data;
56	ASSERT_EQ(bswap_16(hdr->magic), BTF_MAGIC, "btf_magic_swapped");
57	ASSERT_EQ(raw_sz, swap_raw_sz, "raw_sizes");
58
59	/* swap it back to native endianness */
60	btf__set_endianness(swap_btf, endian);
61	swap_raw_data = btf__raw_data(swap_btf, &swap_raw_sz);
62	if (!ASSERT_OK_PTR(swap_raw_data, "swap_raw_data"))
63		goto err_out;
64
65	/* now header should have native BTF_MAGIC */
66	hdr = swap_raw_data;
67	ASSERT_EQ(hdr->magic, BTF_MAGIC, "btf_magic_native");
68	ASSERT_EQ(raw_sz, swap_raw_sz, "raw_sizes");
69
70	/* now modify original BTF */
71	var_id = btf__add_var(btf, "some_var", BTF_VAR_GLOBAL_ALLOCATED, 1);
72	ASSERT_GT(var_id, 0, "var_id");
73
74	btf__free(swap_btf);
75	swap_btf = NULL;
76
77	btf__set_endianness(btf, swap_endian);
78	raw_data = btf__raw_data(btf, &raw_sz);
79	if (!ASSERT_OK_PTR(raw_data, "raw_data_inverted"))
80		goto err_out;
81
82	/* and re-open swapped raw data again */
83	swap_btf = btf__new(raw_data, raw_sz);
84	if (!ASSERT_OK_PTR(swap_btf, "parse_swap_btf"))
85		goto err_out;
86
87	ASSERT_EQ(btf__endianness(swap_btf), swap_endian, "endian");
88	ASSERT_EQ(btf__type_cnt(swap_btf), btf__type_cnt(btf), "nr_types");
89
90	/* the type should appear as if it was stored in native endianness */
91	t = btf__type_by_id(swap_btf, var_id);
92	ASSERT_STREQ(btf__str_by_offset(swap_btf, t->name_off), "some_var", "var_name");
93	ASSERT_EQ(btf_var(t)->linkage, BTF_VAR_GLOBAL_ALLOCATED, "var_linkage");
94	ASSERT_EQ(t->type, 1, "var_type");
95
96err_out:
97	btf__free(btf);
98	btf__free(swap_btf);
99}
100