xref: /linux/tools/lib/bpf/btf.h (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2018 Facebook */
3 /*! \file */
4 
5 #ifndef __LIBBPF_BTF_H
6 #define __LIBBPF_BTF_H
7 
8 #include <stdarg.h>
9 #include <stdbool.h>
10 #include <linux/btf.h>
11 #include <linux/types.h>
12 
13 #include "libbpf_common.h"
14 
15 #ifdef __cplusplus
16 extern "C" {
17 #endif
18 
19 #define BTF_ELF_SEC ".BTF"
20 #define BTF_EXT_ELF_SEC ".BTF.ext"
21 #define BTF_BASE_ELF_SEC ".BTF.base"
22 #define MAPS_ELF_SEC ".maps"
23 
24 struct btf;
25 struct btf_ext;
26 struct btf_type;
27 
28 struct bpf_object;
29 
30 enum btf_endianness {
31 	BTF_LITTLE_ENDIAN = 0,
32 	BTF_BIG_ENDIAN = 1,
33 };
34 
35 /**
36  * @brief **btf__free()** frees all data of a BTF object
37  * @param btf BTF object to free
38  */
39 LIBBPF_API void btf__free(struct btf *btf);
40 
41 /**
42  * @brief **btf__new()** creates a new instance of a BTF object from the raw
43  * bytes of an ELF's BTF section
44  * @param data raw bytes
45  * @param size number of bytes passed in `data`
46  * @return new BTF object instance which has to be eventually freed with
47  * **btf__free()**
48  *
49  * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
50  * error code from such a pointer `libbpf_get_error()` should be used. If
51  * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
52  * returned on error instead. In both cases thread-local `errno` variable is
53  * always set to error code as well.
54  */
55 LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
56 
57 /**
58  * @brief **btf__new_split()** create a new instance of a BTF object from the
59  * provided raw data bytes. It takes another BTF instance, **base_btf**, which
60  * serves as a base BTF, which is extended by types in a newly created BTF
61  * instance
62  * @param data raw bytes
63  * @param size length of raw bytes
64  * @param base_btf the base BTF object
65  * @return new BTF object instance which has to be eventually freed with
66  * **btf__free()**
67  *
68  * If *base_btf* is NULL, `btf__new_split()` is equivalent to `btf__new()` and
69  * creates non-split BTF.
70  *
71  * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
72  * error code from such a pointer `libbpf_get_error()` should be used. If
73  * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
74  * returned on error instead. In both cases thread-local `errno` variable is
75  * always set to error code as well.
76  */
77 LIBBPF_API struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf);
78 
79 /**
80  * @brief **btf__new_empty()** creates an empty BTF object.  Use
81  * `btf__add_*()` to populate such BTF object.
82  * @return new BTF object instance which has to be eventually freed with
83  * **btf__free()**
84  *
85  * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
86  * error code from such a pointer `libbpf_get_error()` should be used. If
87  * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
88  * returned on error instead. In both cases thread-local `errno` variable is
89  * always set to error code as well.
90  */
91 LIBBPF_API struct btf *btf__new_empty(void);
92 
93 /**
94  * @brief **btf__new_empty_split()** creates an unpopulated BTF object from an
95  * ELF BTF section except with a base BTF on top of which split BTF should be
96  * based
97  * @return new BTF object instance which has to be eventually freed with
98  * **btf__free()**
99  *
100  * If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to
101  * `btf__new_empty()` and creates non-split BTF.
102  *
103  * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
104  * error code from such a pointer `libbpf_get_error()` should be used. If
105  * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
106  * returned on error instead. In both cases thread-local `errno` variable is
107  * always set to error code as well.
108  */
109 LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
110 
111 /**
112  * @brief **btf__distill_base()** creates new versions of the split BTF
113  * *src_btf* and its base BTF. The new base BTF will only contain the types
114  * needed to improve robustness of the split BTF to small changes in base BTF.
115  * When that split BTF is loaded against a (possibly changed) base, this
116  * distilled base BTF will help update references to that (possibly changed)
117  * base BTF.
118  *
119  * Both the new split and its associated new base BTF must be freed by
120  * the caller.
121  *
122  * If successful, 0 is returned and **new_base_btf** and **new_split_btf**
123  * will point at new base/split BTF. Both the new split and its associated
124  * new base BTF must be freed by the caller.
125  *
126  * A negative value is returned on error and the thread-local `errno` variable
127  * is set to the error code as well.
128  */
129 LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf,
130 				 struct btf **new_split_btf);
131 
132 LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
133 LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
134 LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
135 LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf);
136 LIBBPF_API struct btf *btf__parse_raw(const char *path);
137 LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
138 
139 LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
140 LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
141 
142 LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
143 LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
144 
145 LIBBPF_API int btf__load_into_kernel(struct btf *btf);
146 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
147 				   const char *type_name);
148 LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
149 					const char *type_name, __u32 kind);
150 LIBBPF_API __u32 btf__type_cnt(const struct btf *btf);
151 LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf);
152 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
153 						  __u32 id);
154 LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
155 LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
156 LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf);
157 LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian);
158 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
159 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
160 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
161 LIBBPF_API int btf__fd(const struct btf *btf);
162 LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
163 LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size);
164 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
165 LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
166 
167 LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
168 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
169 LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
170 
171 LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
172 LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
173 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
174 			     const struct btf_type *src_type);
175 /**
176  * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
177  * @param btf BTF object which all the BTF types and strings are added to
178  * @param src_btf BTF object which all BTF types and referenced strings are copied from
179  * @return BTF type ID of the first appended BTF type, or negative error code
180  *
181  * **btf__add_btf()** can be used to simply and efficiently append the entire
182  * contents of one BTF object to another one. All the BTF type data is copied
183  * over, all referenced type IDs are adjusted by adding a necessary ID offset.
184  * Only strings referenced from BTF types are copied over and deduplicated, so
185  * if there were some unused strings in *src_btf*, those won't be copied over,
186  * which is consistent with the general string deduplication semantics of BTF
187  * writing APIs.
188  *
189  * If any error is encountered during this process, the contents of *btf* is
190  * left intact, which means that **btf__add_btf()** follows the transactional
191  * semantics and the operation as a whole is all-or-nothing.
192  *
193  * *src_btf* has to be non-split BTF, as of now copying types from split BTF
194  * is not supported and will result in -ENOTSUP error code returned.
195  */
196 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
197 
198 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
199 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
200 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
201 LIBBPF_API int btf__add_array(struct btf *btf,
202 			      int index_type_id, int elem_type_id, __u32 nr_elems);
203 /* struct/union construction APIs */
204 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
205 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
206 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
207 			      __u32 bit_offset, __u32 bit_size);
208 
209 /* enum construction APIs */
210 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
211 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
212 LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
213 LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
214 
215 enum btf_fwd_kind {
216 	BTF_FWD_STRUCT = 0,
217 	BTF_FWD_UNION = 1,
218 	BTF_FWD_ENUM = 2,
219 };
220 
221 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
222 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
223 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
224 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
225 LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
226 LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
227 
228 /* func and func_proto construction APIs */
229 LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
230 			     enum btf_func_linkage linkage, int proto_type_id);
231 LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
232 LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
233 
234 /* var & datasec construction APIs */
235 LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
236 LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
237 LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
238 					 __u32 offset, __u32 byte_sz);
239 
240 /* tag construction API */
241 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
242 			    int component_idx);
243 
244 struct btf_dedup_opts {
245 	size_t sz;
246 	/* optional .BTF.ext info to dedup along the main BTF info */
247 	struct btf_ext *btf_ext;
248 	/* force hash collisions (used for testing) */
249 	bool force_collisions;
250 	size_t :0;
251 };
252 #define btf_dedup_opts__last_field force_collisions
253 
254 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
255 
256 /**
257  * @brief **btf__relocate()** will check the split BTF *btf* for references
258  * to base BTF kinds, and verify those references are compatible with
259  * *base_btf*; if they are, *btf* is adjusted such that is re-parented to
260  * *base_btf* and type ids and strings are adjusted to accommodate this.
261  *
262  * If successful, 0 is returned and **btf** now has **base_btf** as its
263  * base.
264  *
265  * A negative value is returned on error and the thread-local `errno` variable
266  * is set to the error code as well.
267  */
268 LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf);
269 
270 struct btf_dump;
271 
272 struct btf_dump_opts {
273 	size_t sz;
274 };
275 #define btf_dump_opts__last_field sz
276 
277 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
278 
279 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
280 					  btf_dump_printf_fn_t printf_fn,
281 					  void *ctx,
282 					  const struct btf_dump_opts *opts);
283 
284 LIBBPF_API void btf_dump__free(struct btf_dump *d);
285 
286 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
287 
288 struct btf_dump_emit_type_decl_opts {
289 	/* size of this struct, for forward/backward compatibility */
290 	size_t sz;
291 	/* optional field name for type declaration, e.g.:
292 	 * - struct my_struct <FNAME>
293 	 * - void (*<FNAME>)(int)
294 	 * - char (*<FNAME>)[123]
295 	 */
296 	const char *field_name;
297 	/* extra indentation level (in number of tabs) to emit for multi-line
298 	 * type declarations (e.g., anonymous struct); applies for lines
299 	 * starting from the second one (first line is assumed to have
300 	 * necessary indentation already
301 	 */
302 	int indent_level;
303 	/* strip all the const/volatile/restrict mods */
304 	bool strip_mods;
305 	size_t :0;
306 };
307 #define btf_dump_emit_type_decl_opts__last_field strip_mods
308 
309 LIBBPF_API int
310 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
311 			 const struct btf_dump_emit_type_decl_opts *opts);
312 
313 
314 struct btf_dump_type_data_opts {
315 	/* size of this struct, for forward/backward compatibility */
316 	size_t sz;
317 	const char *indent_str;
318 	int indent_level;
319 	/* below match "show" flags for bpf_show_snprintf() */
320 	bool compact;		/* no newlines/indentation */
321 	bool skip_names;	/* skip member/type names */
322 	bool emit_zeroes;	/* show 0-valued fields */
323 	size_t :0;
324 };
325 #define btf_dump_type_data_opts__last_field emit_zeroes
326 
327 LIBBPF_API int
328 btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
329 			 const void *data, size_t data_sz,
330 			 const struct btf_dump_type_data_opts *opts);
331 
332 /*
333  * A set of helpers for easier BTF types handling.
334  *
335  * The inline functions below rely on constants from the kernel headers which
336  * may not be available for applications including this header file. To avoid
337  * compilation errors, we define all the constants here that were added after
338  * the initial introduction of the BTF_KIND* constants.
339  */
340 #ifndef BTF_KIND_FUNC
341 #define BTF_KIND_FUNC		12	/* Function	*/
342 #define BTF_KIND_FUNC_PROTO	13	/* Function Proto	*/
343 #endif
344 #ifndef BTF_KIND_VAR
345 #define BTF_KIND_VAR		14	/* Variable	*/
346 #define BTF_KIND_DATASEC	15	/* Section	*/
347 #endif
348 #ifndef BTF_KIND_FLOAT
349 #define BTF_KIND_FLOAT		16	/* Floating point	*/
350 #endif
351 /* The kernel header switched to enums, so the following were never #defined */
352 #define BTF_KIND_DECL_TAG	17	/* Decl Tag */
353 #define BTF_KIND_TYPE_TAG	18	/* Type Tag */
354 #define BTF_KIND_ENUM64		19	/* Enum for up-to 64bit values */
355 
356 static inline __u16 btf_kind(const struct btf_type *t)
357 {
358 	return BTF_INFO_KIND(t->info);
359 }
360 
361 static inline __u16 btf_vlen(const struct btf_type *t)
362 {
363 	return BTF_INFO_VLEN(t->info);
364 }
365 
366 static inline bool btf_kflag(const struct btf_type *t)
367 {
368 	return BTF_INFO_KFLAG(t->info);
369 }
370 
371 static inline bool btf_is_void(const struct btf_type *t)
372 {
373 	return btf_kind(t) == BTF_KIND_UNKN;
374 }
375 
376 static inline bool btf_is_int(const struct btf_type *t)
377 {
378 	return btf_kind(t) == BTF_KIND_INT;
379 }
380 
381 static inline bool btf_is_ptr(const struct btf_type *t)
382 {
383 	return btf_kind(t) == BTF_KIND_PTR;
384 }
385 
386 static inline bool btf_is_array(const struct btf_type *t)
387 {
388 	return btf_kind(t) == BTF_KIND_ARRAY;
389 }
390 
391 static inline bool btf_is_struct(const struct btf_type *t)
392 {
393 	return btf_kind(t) == BTF_KIND_STRUCT;
394 }
395 
396 static inline bool btf_is_union(const struct btf_type *t)
397 {
398 	return btf_kind(t) == BTF_KIND_UNION;
399 }
400 
401 static inline bool btf_is_composite(const struct btf_type *t)
402 {
403 	__u16 kind = btf_kind(t);
404 
405 	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
406 }
407 
408 static inline bool btf_is_enum(const struct btf_type *t)
409 {
410 	return btf_kind(t) == BTF_KIND_ENUM;
411 }
412 
413 static inline bool btf_is_enum64(const struct btf_type *t)
414 {
415 	return btf_kind(t) == BTF_KIND_ENUM64;
416 }
417 
418 static inline bool btf_is_fwd(const struct btf_type *t)
419 {
420 	return btf_kind(t) == BTF_KIND_FWD;
421 }
422 
423 static inline bool btf_is_typedef(const struct btf_type *t)
424 {
425 	return btf_kind(t) == BTF_KIND_TYPEDEF;
426 }
427 
428 static inline bool btf_is_volatile(const struct btf_type *t)
429 {
430 	return btf_kind(t) == BTF_KIND_VOLATILE;
431 }
432 
433 static inline bool btf_is_const(const struct btf_type *t)
434 {
435 	return btf_kind(t) == BTF_KIND_CONST;
436 }
437 
438 static inline bool btf_is_restrict(const struct btf_type *t)
439 {
440 	return btf_kind(t) == BTF_KIND_RESTRICT;
441 }
442 
443 static inline bool btf_is_mod(const struct btf_type *t)
444 {
445 	__u16 kind = btf_kind(t);
446 
447 	return kind == BTF_KIND_VOLATILE ||
448 	       kind == BTF_KIND_CONST ||
449 	       kind == BTF_KIND_RESTRICT ||
450 	       kind == BTF_KIND_TYPE_TAG;
451 }
452 
453 static inline bool btf_is_func(const struct btf_type *t)
454 {
455 	return btf_kind(t) == BTF_KIND_FUNC;
456 }
457 
458 static inline bool btf_is_func_proto(const struct btf_type *t)
459 {
460 	return btf_kind(t) == BTF_KIND_FUNC_PROTO;
461 }
462 
463 static inline bool btf_is_var(const struct btf_type *t)
464 {
465 	return btf_kind(t) == BTF_KIND_VAR;
466 }
467 
468 static inline bool btf_is_datasec(const struct btf_type *t)
469 {
470 	return btf_kind(t) == BTF_KIND_DATASEC;
471 }
472 
473 static inline bool btf_is_float(const struct btf_type *t)
474 {
475 	return btf_kind(t) == BTF_KIND_FLOAT;
476 }
477 
478 static inline bool btf_is_decl_tag(const struct btf_type *t)
479 {
480 	return btf_kind(t) == BTF_KIND_DECL_TAG;
481 }
482 
483 static inline bool btf_is_type_tag(const struct btf_type *t)
484 {
485 	return btf_kind(t) == BTF_KIND_TYPE_TAG;
486 }
487 
488 static inline bool btf_is_any_enum(const struct btf_type *t)
489 {
490 	return btf_is_enum(t) || btf_is_enum64(t);
491 }
492 
493 static inline bool btf_kind_core_compat(const struct btf_type *t1,
494 					const struct btf_type *t2)
495 {
496 	return btf_kind(t1) == btf_kind(t2) ||
497 	       (btf_is_any_enum(t1) && btf_is_any_enum(t2));
498 }
499 
500 static inline __u8 btf_int_encoding(const struct btf_type *t)
501 {
502 	return BTF_INT_ENCODING(*(__u32 *)(t + 1));
503 }
504 
505 static inline __u8 btf_int_offset(const struct btf_type *t)
506 {
507 	return BTF_INT_OFFSET(*(__u32 *)(t + 1));
508 }
509 
510 static inline __u8 btf_int_bits(const struct btf_type *t)
511 {
512 	return BTF_INT_BITS(*(__u32 *)(t + 1));
513 }
514 
515 static inline struct btf_array *btf_array(const struct btf_type *t)
516 {
517 	return (struct btf_array *)(t + 1);
518 }
519 
520 static inline struct btf_enum *btf_enum(const struct btf_type *t)
521 {
522 	return (struct btf_enum *)(t + 1);
523 }
524 
525 struct btf_enum64;
526 
527 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
528 {
529 	return (struct btf_enum64 *)(t + 1);
530 }
531 
532 static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
533 {
534 	/* struct btf_enum64 is introduced in Linux 6.0, which is very
535 	 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
536 	 * definition coming from kernel UAPI headers to support wider range
537 	 * of system-wide kernel headers.
538 	 *
539 	 * Given this header can be also included from C++ applications, that
540 	 * further restricts C tricks we can use (like using compatible
541 	 * anonymous struct). So just treat struct btf_enum64 as
542 	 * a three-element array of u32 and access second (lo32) and third
543 	 * (hi32) elements directly.
544 	 *
545 	 * For reference, here is a struct btf_enum64 definition:
546 	 *
547 	 * const struct btf_enum64 {
548 	 *	__u32	name_off;
549 	 *	__u32	val_lo32;
550 	 *	__u32	val_hi32;
551 	 * };
552 	 */
553 	const __u32 *e64 = (const __u32 *)e;
554 
555 	return ((__u64)e64[2] << 32) | e64[1];
556 }
557 
558 static inline struct btf_member *btf_members(const struct btf_type *t)
559 {
560 	return (struct btf_member *)(t + 1);
561 }
562 
563 /* Get bit offset of a member with specified index. */
564 static inline __u32 btf_member_bit_offset(const struct btf_type *t,
565 					  __u32 member_idx)
566 {
567 	const struct btf_member *m = btf_members(t) + member_idx;
568 	bool kflag = btf_kflag(t);
569 
570 	return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
571 }
572 /*
573  * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
574  * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
575  */
576 static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
577 					     __u32 member_idx)
578 {
579 	const struct btf_member *m = btf_members(t) + member_idx;
580 	bool kflag = btf_kflag(t);
581 
582 	return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
583 }
584 
585 static inline struct btf_param *btf_params(const struct btf_type *t)
586 {
587 	return (struct btf_param *)(t + 1);
588 }
589 
590 static inline struct btf_var *btf_var(const struct btf_type *t)
591 {
592 	return (struct btf_var *)(t + 1);
593 }
594 
595 static inline struct btf_var_secinfo *
596 btf_var_secinfos(const struct btf_type *t)
597 {
598 	return (struct btf_var_secinfo *)(t + 1);
599 }
600 
601 struct btf_decl_tag;
602 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
603 {
604 	return (struct btf_decl_tag *)(t + 1);
605 }
606 
607 #ifdef __cplusplus
608 } /* extern "C" */
609 #endif
610 
611 #endif /* __LIBBPF_BTF_H */
612