1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2018 Facebook */
3
4 #ifndef __LIBBPF_BTF_H
5 #define __LIBBPF_BTF_H
6
7 #include <stdarg.h>
8 #include <linux/btf.h>
9 #include <linux/types.h>
10
11 #ifdef __cplusplus
12 extern "C" {
13 #endif
14
15 #ifndef LIBBPF_API
16 #define LIBBPF_API __attribute__((visibility("default")))
17 #endif
18
19 #define BTF_ELF_SEC ".BTF"
20 #define BTF_EXT_ELF_SEC ".BTF.ext"
21 #define MAPS_ELF_SEC ".maps"
22
23 struct btf;
24 struct btf_ext;
25 struct btf_type;
26
27 struct bpf_object;
28
29 /*
30 * The .BTF.ext ELF section layout defined as
31 * struct btf_ext_header
32 * func_info subsection
33 *
34 * The func_info subsection layout:
35 * record size for struct bpf_func_info in the func_info subsection
36 * struct btf_sec_func_info for section #1
37 * a list of bpf_func_info records for section #1
38 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
39 * but may not be identical
40 * struct btf_sec_func_info for section #2
41 * a list of bpf_func_info records for section #2
42 * ......
43 *
44 * Note that the bpf_func_info record size in .BTF.ext may not
45 * be the same as the one defined in include/uapi/linux/bpf.h.
46 * The loader should ensure that record_size meets minimum
47 * requirement and pass the record as is to the kernel. The
48 * kernel will handle the func_info properly based on its contents.
49 */
50 struct btf_ext_header {
51 __u16 magic;
52 __u8 version;
53 __u8 flags;
54 __u32 hdr_len;
55
56 /* All offsets are in bytes relative to the end of this header */
57 __u32 func_info_off;
58 __u32 func_info_len;
59 __u32 line_info_off;
60 __u32 line_info_len;
61
62 /* optional part of .BTF.ext header */
63 __u32 offset_reloc_off;
64 __u32 offset_reloc_len;
65 };
66
67 LIBBPF_API void btf__free(struct btf *btf);
68 LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size);
69 LIBBPF_API struct btf *btf__parse_elf(const char *path,
70 struct btf_ext **btf_ext);
71 LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
72 LIBBPF_API int btf__load(struct btf *btf);
73 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
74 const char *type_name);
75 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
76 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
77 __u32 id);
78 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
79 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
80 LIBBPF_API int btf__fd(const struct btf *btf);
81 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
82 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
83 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
84 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
85 __u32 expected_key_size,
86 __u32 expected_value_size,
87 __u32 *key_type_id, __u32 *value_type_id);
88
89 LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
90 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
91 LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
92 __u32 *size);
93 LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
94 const struct btf_ext *btf_ext,
95 const char *sec_name, __u32 insns_cnt,
96 void **func_info, __u32 *cnt);
97 LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
98 const struct btf_ext *btf_ext,
99 const char *sec_name, __u32 insns_cnt,
100 void **line_info, __u32 *cnt);
101 LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
102 LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
103
104 struct btf_dedup_opts {
105 unsigned int dedup_table_size;
106 bool dont_resolve_fwds;
107 };
108
109 LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
110 const struct btf_dedup_opts *opts);
111
112 struct btf_dump;
113
114 struct btf_dump_opts {
115 void *ctx;
116 };
117
118 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
119
120 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
121 const struct btf_ext *btf_ext,
122 const struct btf_dump_opts *opts,
123 btf_dump_printf_fn_t printf_fn);
124 LIBBPF_API void btf_dump__free(struct btf_dump *d);
125
126 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
127
128 /*
129 * A set of helpers for easier BTF types handling
130 */
btf_kind(const struct btf_type * t)131 static inline __u16 btf_kind(const struct btf_type *t)
132 {
133 return BTF_INFO_KIND(t->info);
134 }
135
btf_vlen(const struct btf_type * t)136 static inline __u16 btf_vlen(const struct btf_type *t)
137 {
138 return BTF_INFO_VLEN(t->info);
139 }
140
btf_kflag(const struct btf_type * t)141 static inline bool btf_kflag(const struct btf_type *t)
142 {
143 return BTF_INFO_KFLAG(t->info);
144 }
145
btf_is_int(const struct btf_type * t)146 static inline bool btf_is_int(const struct btf_type *t)
147 {
148 return btf_kind(t) == BTF_KIND_INT;
149 }
150
btf_is_ptr(const struct btf_type * t)151 static inline bool btf_is_ptr(const struct btf_type *t)
152 {
153 return btf_kind(t) == BTF_KIND_PTR;
154 }
155
btf_is_array(const struct btf_type * t)156 static inline bool btf_is_array(const struct btf_type *t)
157 {
158 return btf_kind(t) == BTF_KIND_ARRAY;
159 }
160
btf_is_struct(const struct btf_type * t)161 static inline bool btf_is_struct(const struct btf_type *t)
162 {
163 return btf_kind(t) == BTF_KIND_STRUCT;
164 }
165
btf_is_union(const struct btf_type * t)166 static inline bool btf_is_union(const struct btf_type *t)
167 {
168 return btf_kind(t) == BTF_KIND_UNION;
169 }
170
btf_is_composite(const struct btf_type * t)171 static inline bool btf_is_composite(const struct btf_type *t)
172 {
173 __u16 kind = btf_kind(t);
174
175 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
176 }
177
btf_is_enum(const struct btf_type * t)178 static inline bool btf_is_enum(const struct btf_type *t)
179 {
180 return btf_kind(t) == BTF_KIND_ENUM;
181 }
182
btf_is_fwd(const struct btf_type * t)183 static inline bool btf_is_fwd(const struct btf_type *t)
184 {
185 return btf_kind(t) == BTF_KIND_FWD;
186 }
187
btf_is_typedef(const struct btf_type * t)188 static inline bool btf_is_typedef(const struct btf_type *t)
189 {
190 return btf_kind(t) == BTF_KIND_TYPEDEF;
191 }
192
btf_is_volatile(const struct btf_type * t)193 static inline bool btf_is_volatile(const struct btf_type *t)
194 {
195 return btf_kind(t) == BTF_KIND_VOLATILE;
196 }
197
btf_is_const(const struct btf_type * t)198 static inline bool btf_is_const(const struct btf_type *t)
199 {
200 return btf_kind(t) == BTF_KIND_CONST;
201 }
202
btf_is_restrict(const struct btf_type * t)203 static inline bool btf_is_restrict(const struct btf_type *t)
204 {
205 return btf_kind(t) == BTF_KIND_RESTRICT;
206 }
207
btf_is_mod(const struct btf_type * t)208 static inline bool btf_is_mod(const struct btf_type *t)
209 {
210 __u16 kind = btf_kind(t);
211
212 return kind == BTF_KIND_VOLATILE ||
213 kind == BTF_KIND_CONST ||
214 kind == BTF_KIND_RESTRICT;
215 }
216
btf_is_func(const struct btf_type * t)217 static inline bool btf_is_func(const struct btf_type *t)
218 {
219 return btf_kind(t) == BTF_KIND_FUNC;
220 }
221
btf_is_func_proto(const struct btf_type * t)222 static inline bool btf_is_func_proto(const struct btf_type *t)
223 {
224 return btf_kind(t) == BTF_KIND_FUNC_PROTO;
225 }
226
btf_is_var(const struct btf_type * t)227 static inline bool btf_is_var(const struct btf_type *t)
228 {
229 return btf_kind(t) == BTF_KIND_VAR;
230 }
231
btf_is_datasec(const struct btf_type * t)232 static inline bool btf_is_datasec(const struct btf_type *t)
233 {
234 return btf_kind(t) == BTF_KIND_DATASEC;
235 }
236
btf_int_encoding(const struct btf_type * t)237 static inline __u8 btf_int_encoding(const struct btf_type *t)
238 {
239 return BTF_INT_ENCODING(*(__u32 *)(t + 1));
240 }
241
btf_int_offset(const struct btf_type * t)242 static inline __u8 btf_int_offset(const struct btf_type *t)
243 {
244 return BTF_INT_OFFSET(*(__u32 *)(t + 1));
245 }
246
btf_int_bits(const struct btf_type * t)247 static inline __u8 btf_int_bits(const struct btf_type *t)
248 {
249 return BTF_INT_BITS(*(__u32 *)(t + 1));
250 }
251
btf_array(const struct btf_type * t)252 static inline struct btf_array *btf_array(const struct btf_type *t)
253 {
254 return (struct btf_array *)(t + 1);
255 }
256
btf_enum(const struct btf_type * t)257 static inline struct btf_enum *btf_enum(const struct btf_type *t)
258 {
259 return (struct btf_enum *)(t + 1);
260 }
261
btf_members(const struct btf_type * t)262 static inline struct btf_member *btf_members(const struct btf_type *t)
263 {
264 return (struct btf_member *)(t + 1);
265 }
266
267 /* Get bit offset of a member with specified index. */
btf_member_bit_offset(const struct btf_type * t,__u32 member_idx)268 static inline __u32 btf_member_bit_offset(const struct btf_type *t,
269 __u32 member_idx)
270 {
271 const struct btf_member *m = btf_members(t) + member_idx;
272 bool kflag = btf_kflag(t);
273
274 return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
275 }
276 /*
277 * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
278 * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
279 */
btf_member_bitfield_size(const struct btf_type * t,__u32 member_idx)280 static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
281 __u32 member_idx)
282 {
283 const struct btf_member *m = btf_members(t) + member_idx;
284 bool kflag = btf_kflag(t);
285
286 return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
287 }
288
btf_params(const struct btf_type * t)289 static inline struct btf_param *btf_params(const struct btf_type *t)
290 {
291 return (struct btf_param *)(t + 1);
292 }
293
btf_var(const struct btf_type * t)294 static inline struct btf_var *btf_var(const struct btf_type *t)
295 {
296 return (struct btf_var *)(t + 1);
297 }
298
299 static inline struct btf_var_secinfo *
btf_var_secinfos(const struct btf_type * t)300 btf_var_secinfos(const struct btf_type *t)
301 {
302 return (struct btf_var_secinfo *)(t + 1);
303 }
304
305 #ifdef __cplusplus
306 } /* extern "C" */
307 #endif
308
309 #endif /* __LIBBPF_BTF_H */
310
