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
test_btf_endian()9 void 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
96 err_out:
97 btf__free(btf);
98 btf__free(swap_btf);
99 }
100