1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 /* Copyright (c) 2021 Facebook */
3 /* Copyright (c) 2024, Oracle and/or its affiliates. */
4
5 #ifdef __KERNEL__
6 #include <linux/bpf.h>
7 #include <linux/btf.h>
8
9 #define btf_var_secinfos(t) (struct btf_var_secinfo *)btf_type_var_secinfo(t)
10
11 #else
12 #include "btf.h"
13 #include "libbpf_internal.h"
14 #endif
15
btf_field_iter_init(struct btf_field_iter * it,struct btf_type * t,enum btf_field_iter_kind iter_kind)16 int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t,
17 enum btf_field_iter_kind iter_kind)
18 {
19 it->p = NULL;
20 it->m_idx = -1;
21 it->off_idx = 0;
22 it->vlen = 0;
23
24 switch (iter_kind) {
25 case BTF_FIELD_ITER_IDS:
26 switch (btf_kind(t)) {
27 case BTF_KIND_UNKN:
28 case BTF_KIND_INT:
29 case BTF_KIND_FLOAT:
30 case BTF_KIND_ENUM:
31 case BTF_KIND_ENUM64:
32 it->desc = (struct btf_field_desc) {};
33 break;
34 case BTF_KIND_FWD:
35 case BTF_KIND_CONST:
36 case BTF_KIND_VOLATILE:
37 case BTF_KIND_RESTRICT:
38 case BTF_KIND_PTR:
39 case BTF_KIND_TYPEDEF:
40 case BTF_KIND_FUNC:
41 case BTF_KIND_VAR:
42 case BTF_KIND_DECL_TAG:
43 case BTF_KIND_TYPE_TAG:
44 it->desc = (struct btf_field_desc) { 1, {offsetof(struct btf_type, type)} };
45 break;
46 case BTF_KIND_ARRAY:
47 it->desc = (struct btf_field_desc) {
48 2, {sizeof(struct btf_type) + offsetof(struct btf_array, type),
49 sizeof(struct btf_type) + offsetof(struct btf_array, index_type)}
50 };
51 break;
52 case BTF_KIND_STRUCT:
53 case BTF_KIND_UNION:
54 it->desc = (struct btf_field_desc) {
55 0, {},
56 sizeof(struct btf_member),
57 1, {offsetof(struct btf_member, type)}
58 };
59 break;
60 case BTF_KIND_FUNC_PROTO:
61 it->desc = (struct btf_field_desc) {
62 1, {offsetof(struct btf_type, type)},
63 sizeof(struct btf_param),
64 1, {offsetof(struct btf_param, type)}
65 };
66 break;
67 case BTF_KIND_DATASEC:
68 it->desc = (struct btf_field_desc) {
69 0, {},
70 sizeof(struct btf_var_secinfo),
71 1, {offsetof(struct btf_var_secinfo, type)}
72 };
73 break;
74 default:
75 return -EINVAL;
76 }
77 break;
78 case BTF_FIELD_ITER_STRS:
79 switch (btf_kind(t)) {
80 case BTF_KIND_UNKN:
81 it->desc = (struct btf_field_desc) {};
82 break;
83 case BTF_KIND_INT:
84 case BTF_KIND_FLOAT:
85 case BTF_KIND_FWD:
86 case BTF_KIND_ARRAY:
87 case BTF_KIND_CONST:
88 case BTF_KIND_VOLATILE:
89 case BTF_KIND_RESTRICT:
90 case BTF_KIND_PTR:
91 case BTF_KIND_TYPEDEF:
92 case BTF_KIND_FUNC:
93 case BTF_KIND_VAR:
94 case BTF_KIND_DECL_TAG:
95 case BTF_KIND_TYPE_TAG:
96 case BTF_KIND_DATASEC:
97 it->desc = (struct btf_field_desc) {
98 1, {offsetof(struct btf_type, name_off)}
99 };
100 break;
101 case BTF_KIND_ENUM:
102 it->desc = (struct btf_field_desc) {
103 1, {offsetof(struct btf_type, name_off)},
104 sizeof(struct btf_enum),
105 1, {offsetof(struct btf_enum, name_off)}
106 };
107 break;
108 case BTF_KIND_ENUM64:
109 it->desc = (struct btf_field_desc) {
110 1, {offsetof(struct btf_type, name_off)},
111 sizeof(struct btf_enum64),
112 1, {offsetof(struct btf_enum64, name_off)}
113 };
114 break;
115 case BTF_KIND_STRUCT:
116 case BTF_KIND_UNION:
117 it->desc = (struct btf_field_desc) {
118 1, {offsetof(struct btf_type, name_off)},
119 sizeof(struct btf_member),
120 1, {offsetof(struct btf_member, name_off)}
121 };
122 break;
123 case BTF_KIND_FUNC_PROTO:
124 it->desc = (struct btf_field_desc) {
125 1, {offsetof(struct btf_type, name_off)},
126 sizeof(struct btf_param),
127 1, {offsetof(struct btf_param, name_off)}
128 };
129 break;
130 default:
131 return -EINVAL;
132 }
133 break;
134 default:
135 return -EINVAL;
136 }
137
138 if (it->desc.m_sz)
139 it->vlen = btf_vlen(t);
140
141 it->p = t;
142 return 0;
143 }
144
btf_field_iter_next(struct btf_field_iter * it)145 __u32 *btf_field_iter_next(struct btf_field_iter *it)
146 {
147 if (!it->p)
148 return NULL;
149
150 if (it->m_idx < 0) {
151 if (it->off_idx < it->desc.t_off_cnt)
152 return it->p + it->desc.t_offs[it->off_idx++];
153 /* move to per-member iteration */
154 it->m_idx = 0;
155 it->p += sizeof(struct btf_type);
156 it->off_idx = 0;
157 }
158
159 /* if type doesn't have members, stop */
160 if (it->desc.m_sz == 0) {
161 it->p = NULL;
162 return NULL;
163 }
164
165 if (it->off_idx >= it->desc.m_off_cnt) {
166 /* exhausted this member's fields, go to the next member */
167 it->m_idx++;
168 it->p += it->desc.m_sz;
169 it->off_idx = 0;
170 }
171
172 if (it->m_idx < it->vlen)
173 return it->p + it->desc.m_offs[it->off_idx++];
174
175 it->p = NULL;
176 return NULL;
177 }
178