xref: /linux/tools/lib/bpf/btf.h (revision 7a5f1cd22d47f8ca4b760b6334378ae42c1bd24b)
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  * @param base_btf base BTF object
98  * @return new BTF object instance which has to be eventually freed with
99  * **btf__free()**
100  *
101  * If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to
102  * `btf__new_empty()` and creates non-split BTF.
103  *
104  * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
105  * error code from such a pointer `libbpf_get_error()` should be used. If
106  * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
107  * returned on error instead. In both cases thread-local `errno` variable is
108  * always set to error code as well.
109  */
110 LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
111 
112 struct btf_new_opts {
113 	size_t sz;
114 	struct btf *base_btf;	/* optional base BTF */
115 	bool add_layout;	/* add BTF layout information */
116 	size_t:0;
117 };
118 #define btf_new_opts__last_field add_layout
119 
120 /**
121  * @brief **btf__new_empty_opts()** creates an unpopulated BTF object with
122  * optional *base_btf* and BTF kind layout description if *add_layout*
123  * is set
124  * @return new BTF object instance which has to be eventually freed with
125  * **btf__free()**
126  *
127  * On error, NULL is returned and the thread-local `errno` variable is
128  * set to the error code.
129  */
130 LIBBPF_API struct btf *btf__new_empty_opts(struct btf_new_opts *opts);
131 
132 /**
133  * @brief **btf__distill_base()** creates new versions of the split BTF
134  * *src_btf* and its base BTF. The new base BTF will only contain the types
135  * needed to improve robustness of the split BTF to small changes in base BTF.
136  * When that split BTF is loaded against a (possibly changed) base, this
137  * distilled base BTF will help update references to that (possibly changed)
138  * base BTF.
139  * @param src_btf source split BTF object
140  * @param new_base_btf pointer to where the new base BTF object pointer will be stored
141  * @param new_split_btf pointer to where the new split BTF object pointer will be stored
142  * @return 0 on success; negative error code, otherwise
143  *
144  * Both the new split and its associated new base BTF must be freed by
145  * the caller.
146  *
147  * If successful, 0 is returned and **new_base_btf** and **new_split_btf**
148  * will point at new base/split BTF. Both the new split and its associated
149  * new base BTF must be freed by the caller.
150  *
151  * A negative value is returned on error and the thread-local `errno` variable
152  * is set to the error code as well.
153  */
154 LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf,
155 				 struct btf **new_split_btf);
156 
157 LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
158 LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
159 LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
160 LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf);
161 LIBBPF_API struct btf *btf__parse_raw(const char *path);
162 LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
163 
164 LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
165 LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
166 
167 LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
168 LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
169 
170 LIBBPF_API int btf__load_into_kernel(struct btf *btf);
171 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
172 				   const char *type_name);
173 LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
174 					const char *type_name, __u32 kind);
175 LIBBPF_API __u32 btf__type_cnt(const struct btf *btf);
176 LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf);
177 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
178 						  __u32 id);
179 LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
180 LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
181 LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf);
182 LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian);
183 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
184 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
185 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
186 LIBBPF_API int btf__fd(const struct btf *btf);
187 LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
188 LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size);
189 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
190 LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
191 
192 LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
193 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
194 LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
195 LIBBPF_API enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext);
196 LIBBPF_API int btf_ext__set_endianness(struct btf_ext *btf_ext,
197 				       enum btf_endianness endian);
198 
199 LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
200 LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
201 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
202 			     const struct btf_type *src_type);
203 /**
204  * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
205  * @param btf BTF object which all the BTF types and strings are added to
206  * @param src_btf BTF object which all BTF types and referenced strings are copied from
207  * @return BTF type ID of the first appended BTF type, or negative error code
208  *
209  * **btf__add_btf()** can be used to simply and efficiently append the entire
210  * contents of one BTF object to another one. All the BTF type data is copied
211  * over, all referenced type IDs are adjusted by adding a necessary ID offset.
212  * Only strings referenced from BTF types are copied over and deduplicated, so
213  * if there were some unused strings in *src_btf*, those won't be copied over,
214  * which is consistent with the general string deduplication semantics of BTF
215  * writing APIs.
216  *
217  * If any error is encountered during this process, the contents of *btf* is
218  * left intact, which means that **btf__add_btf()** follows the transactional
219  * semantics and the operation as a whole is all-or-nothing.
220  *
221  * *src_btf* has to be non-split BTF, as of now copying types from split BTF
222  * is not supported and will result in -ENOTSUP error code returned.
223  */
224 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
225 
226 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
227 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
228 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
229 LIBBPF_API int btf__add_array(struct btf *btf,
230 			      int index_type_id, int elem_type_id, __u32 nr_elems);
231 /* struct/union construction APIs */
232 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
233 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
234 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
235 			      __u32 bit_offset, __u32 bit_size);
236 
237 /* enum construction APIs */
238 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
239 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
240 LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
241 LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
242 
243 enum btf_fwd_kind {
244 	BTF_FWD_STRUCT = 0,
245 	BTF_FWD_UNION = 1,
246 	BTF_FWD_ENUM = 2,
247 };
248 
249 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
250 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
251 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
252 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
253 LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
254 LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
255 LIBBPF_API int btf__add_type_attr(struct btf *btf, const char *value, int ref_type_id);
256 
257 /* func and func_proto construction APIs */
258 LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
259 			     enum btf_func_linkage linkage, int proto_type_id);
260 LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
261 LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
262 
263 /* var & datasec construction APIs */
264 LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
265 LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
266 LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
267 					 __u32 offset, __u32 byte_sz);
268 
269 /* tag construction API */
270 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
271 			    int component_idx);
272 LIBBPF_API int btf__add_decl_attr(struct btf *btf, const char *value, int ref_type_id,
273 				  int component_idx);
274 
275 struct btf_dedup_opts {
276 	size_t sz;
277 	/* optional .BTF.ext info to dedup along the main BTF info */
278 	struct btf_ext *btf_ext;
279 	/* force hash collisions (used for testing) */
280 	bool force_collisions;
281 	size_t :0;
282 };
283 #define btf_dedup_opts__last_field force_collisions
284 
285 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
286 
287 /**
288  * @brief **btf__relocate()** will check the split BTF *btf* for references
289  * to base BTF kinds, and verify those references are compatible with
290  * *base_btf*; if they are, *btf* is adjusted such that is re-parented to
291  * *base_btf* and type ids and strings are adjusted to accommodate this.
292  * @param btf split BTF object to relocate
293  * @param base_btf base BTF object
294  * @return 0 on success; negative error code, otherwise
295  *
296  * If successful, 0 is returned and **btf** now has **base_btf** as its
297  * base.
298  *
299  * A negative value is returned on error and the thread-local `errno` variable
300  * is set to the error code as well.
301  */
302 LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf);
303 
304 struct btf_permute_opts {
305 	size_t sz;
306 	/* optional .BTF.ext info along the main BTF info */
307 	struct btf_ext *btf_ext;
308 	size_t :0;
309 };
310 #define btf_permute_opts__last_field btf_ext
311 
312 /**
313  * @brief **btf__permute()** rearranges BTF types in-place according to a specified ID mapping
314  * @param btf BTF object to permute
315  * @param id_map Array mapping original type IDs to new IDs
316  * @param id_map_cnt Number of elements in @id_map
317  * @param opts Optional parameters, including BTF extension data for reference updates
318  * @return 0 on success, negative error code on failure
319  *
320  * **btf__permute()** reorders BTF types based on the provided @id_map array,
321  * updating all internal type references to maintain consistency. The function
322  * operates in-place, modifying the BTF object directly.
323  *
324  * For **base BTF**:
325  * - @id_map must include all types from ID 0 to `btf__type_cnt(btf) - 1`
326  * - @id_map_cnt must be `btf__type_cnt(btf)`
327  * - Mapping is defined as `id_map[original_id] = new_id`
328  * - `id_map[0]` must be 0 (void type cannot be moved)
329  *
330  * For **split BTF**:
331  * - @id_map must include only split types (types added on top of the base BTF)
332  * - @id_map_cnt must be `btf__type_cnt(btf) - btf__type_cnt(btf__base_btf(btf))`
333  * - Mapping is defined as `id_map[original_id - start_id] = new_id`
334  * - `start_id` equals `btf__type_cnt(btf__base_btf(btf))`
335  *
336  * After permutation, all type references within the BTF data and optional
337  * BTF extension (if provided via @opts) are updated automatically.
338  *
339  * On error, returns a negative error code and sets errno:
340  *   - `-EINVAL`: Invalid parameters or invalid ID mapping
341  *   - `-ENOMEM`: Memory allocation failure
342  */
343 LIBBPF_API int btf__permute(struct btf *btf, __u32 *id_map, __u32 id_map_cnt,
344 			    const struct btf_permute_opts *opts);
345 
346 struct btf_dump;
347 
348 struct btf_dump_opts {
349 	size_t sz;
350 };
351 #define btf_dump_opts__last_field sz
352 
353 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
354 
355 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
356 					  btf_dump_printf_fn_t printf_fn,
357 					  void *ctx,
358 					  const struct btf_dump_opts *opts);
359 
360 LIBBPF_API void btf_dump__free(struct btf_dump *d);
361 
362 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
363 
364 struct btf_dump_emit_type_decl_opts {
365 	/* size of this struct, for forward/backward compatibility */
366 	size_t sz;
367 	/* optional field name for type declaration, e.g.:
368 	 * - struct my_struct <FNAME>
369 	 * - void (*<FNAME>)(int)
370 	 * - char (*<FNAME>)[123]
371 	 */
372 	const char *field_name;
373 	/* extra indentation level (in number of tabs) to emit for multi-line
374 	 * type declarations (e.g., anonymous struct); applies for lines
375 	 * starting from the second one (first line is assumed to have
376 	 * necessary indentation already
377 	 */
378 	int indent_level;
379 	/* strip all the const/volatile/restrict mods */
380 	bool strip_mods;
381 	size_t :0;
382 };
383 #define btf_dump_emit_type_decl_opts__last_field strip_mods
384 
385 LIBBPF_API int
386 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
387 			 const struct btf_dump_emit_type_decl_opts *opts);
388 
389 
390 struct btf_dump_type_data_opts {
391 	/* size of this struct, for forward/backward compatibility */
392 	size_t sz;
393 	const char *indent_str;
394 	int indent_level;
395 	/* below match "show" flags for bpf_show_snprintf() */
396 	bool compact;		/* no newlines/indentation */
397 	bool skip_names;	/* skip member/type names */
398 	bool emit_zeroes;	/* show 0-valued fields */
399 	bool emit_strings;	/* print char arrays as strings */
400 	size_t :0;
401 };
402 #define btf_dump_type_data_opts__last_field emit_strings
403 
404 LIBBPF_API int
405 btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
406 			 const void *data, size_t data_sz,
407 			 const struct btf_dump_type_data_opts *opts);
408 
409 /*
410  * A set of helpers for easier BTF types handling.
411  *
412  * The inline functions below rely on constants from the kernel headers which
413  * may not be available for applications including this header file. To avoid
414  * compilation errors, we define all the constants here that were added after
415  * the initial introduction of the BTF_KIND* constants.
416  */
417 #ifndef BTF_KIND_FUNC
418 #define BTF_KIND_FUNC		12	/* Function	*/
419 #define BTF_KIND_FUNC_PROTO	13	/* Function Proto	*/
420 #endif
421 #ifndef BTF_KIND_VAR
422 #define BTF_KIND_VAR		14	/* Variable	*/
423 #define BTF_KIND_DATASEC	15	/* Section	*/
424 #endif
425 #ifndef BTF_KIND_FLOAT
426 #define BTF_KIND_FLOAT		16	/* Floating point	*/
427 #endif
428 /* The kernel header switched to enums, so the following were never #defined */
429 #define BTF_KIND_DECL_TAG	17	/* Decl Tag */
430 #define BTF_KIND_TYPE_TAG	18	/* Type Tag */
431 #define BTF_KIND_ENUM64		19	/* Enum for up-to 64bit values */
432 
433 static inline __u16 btf_kind(const struct btf_type *t)
434 {
435 	return BTF_INFO_KIND(t->info);
436 }
437 
438 static inline __u16 btf_vlen(const struct btf_type *t)
439 {
440 	return BTF_INFO_VLEN(t->info);
441 }
442 
443 static inline bool btf_kflag(const struct btf_type *t)
444 {
445 	return BTF_INFO_KFLAG(t->info);
446 }
447 
448 static inline bool btf_is_void(const struct btf_type *t)
449 {
450 	return btf_kind(t) == BTF_KIND_UNKN;
451 }
452 
453 static inline bool btf_is_int(const struct btf_type *t)
454 {
455 	return btf_kind(t) == BTF_KIND_INT;
456 }
457 
458 static inline bool btf_is_ptr(const struct btf_type *t)
459 {
460 	return btf_kind(t) == BTF_KIND_PTR;
461 }
462 
463 static inline bool btf_is_array(const struct btf_type *t)
464 {
465 	return btf_kind(t) == BTF_KIND_ARRAY;
466 }
467 
468 static inline bool btf_is_struct(const struct btf_type *t)
469 {
470 	return btf_kind(t) == BTF_KIND_STRUCT;
471 }
472 
473 static inline bool btf_is_union(const struct btf_type *t)
474 {
475 	return btf_kind(t) == BTF_KIND_UNION;
476 }
477 
478 static inline bool btf_is_composite(const struct btf_type *t)
479 {
480 	__u16 kind = btf_kind(t);
481 
482 	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
483 }
484 
485 static inline bool btf_is_enum(const struct btf_type *t)
486 {
487 	return btf_kind(t) == BTF_KIND_ENUM;
488 }
489 
490 static inline bool btf_is_enum64(const struct btf_type *t)
491 {
492 	return btf_kind(t) == BTF_KIND_ENUM64;
493 }
494 
495 static inline bool btf_is_fwd(const struct btf_type *t)
496 {
497 	return btf_kind(t) == BTF_KIND_FWD;
498 }
499 
500 static inline bool btf_is_typedef(const struct btf_type *t)
501 {
502 	return btf_kind(t) == BTF_KIND_TYPEDEF;
503 }
504 
505 static inline bool btf_is_volatile(const struct btf_type *t)
506 {
507 	return btf_kind(t) == BTF_KIND_VOLATILE;
508 }
509 
510 static inline bool btf_is_const(const struct btf_type *t)
511 {
512 	return btf_kind(t) == BTF_KIND_CONST;
513 }
514 
515 static inline bool btf_is_restrict(const struct btf_type *t)
516 {
517 	return btf_kind(t) == BTF_KIND_RESTRICT;
518 }
519 
520 static inline bool btf_is_mod(const struct btf_type *t)
521 {
522 	__u16 kind = btf_kind(t);
523 
524 	return kind == BTF_KIND_VOLATILE ||
525 	       kind == BTF_KIND_CONST ||
526 	       kind == BTF_KIND_RESTRICT ||
527 	       kind == BTF_KIND_TYPE_TAG;
528 }
529 
530 static inline bool btf_is_func(const struct btf_type *t)
531 {
532 	return btf_kind(t) == BTF_KIND_FUNC;
533 }
534 
535 static inline bool btf_is_func_proto(const struct btf_type *t)
536 {
537 	return btf_kind(t) == BTF_KIND_FUNC_PROTO;
538 }
539 
540 static inline bool btf_is_var(const struct btf_type *t)
541 {
542 	return btf_kind(t) == BTF_KIND_VAR;
543 }
544 
545 static inline bool btf_is_datasec(const struct btf_type *t)
546 {
547 	return btf_kind(t) == BTF_KIND_DATASEC;
548 }
549 
550 static inline bool btf_is_float(const struct btf_type *t)
551 {
552 	return btf_kind(t) == BTF_KIND_FLOAT;
553 }
554 
555 static inline bool btf_is_decl_tag(const struct btf_type *t)
556 {
557 	return btf_kind(t) == BTF_KIND_DECL_TAG;
558 }
559 
560 static inline bool btf_is_type_tag(const struct btf_type *t)
561 {
562 	return btf_kind(t) == BTF_KIND_TYPE_TAG;
563 }
564 
565 static inline bool btf_is_any_enum(const struct btf_type *t)
566 {
567 	return btf_is_enum(t) || btf_is_enum64(t);
568 }
569 
570 static inline bool btf_kind_core_compat(const struct btf_type *t1,
571 					const struct btf_type *t2)
572 {
573 	return btf_kind(t1) == btf_kind(t2) ||
574 	       (btf_is_any_enum(t1) && btf_is_any_enum(t2));
575 }
576 
577 static inline __u8 btf_int_encoding(const struct btf_type *t)
578 {
579 	return BTF_INT_ENCODING(*(__u32 *)(t + 1));
580 }
581 
582 static inline __u8 btf_int_offset(const struct btf_type *t)
583 {
584 	return BTF_INT_OFFSET(*(__u32 *)(t + 1));
585 }
586 
587 static inline __u8 btf_int_bits(const struct btf_type *t)
588 {
589 	return BTF_INT_BITS(*(__u32 *)(t + 1));
590 }
591 
592 static inline struct btf_array *btf_array(const struct btf_type *t)
593 {
594 	return (struct btf_array *)(t + 1);
595 }
596 
597 static inline struct btf_enum *btf_enum(const struct btf_type *t)
598 {
599 	return (struct btf_enum *)(t + 1);
600 }
601 
602 struct btf_enum64;
603 
604 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
605 {
606 	return (struct btf_enum64 *)(t + 1);
607 }
608 
609 static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
610 {
611 	/* struct btf_enum64 is introduced in Linux 6.0, which is very
612 	 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
613 	 * definition coming from kernel UAPI headers to support wider range
614 	 * of system-wide kernel headers.
615 	 *
616 	 * Given this header can be also included from C++ applications, that
617 	 * further restricts C tricks we can use (like using compatible
618 	 * anonymous struct). So just treat struct btf_enum64 as
619 	 * a three-element array of u32 and access second (lo32) and third
620 	 * (hi32) elements directly.
621 	 *
622 	 * For reference, here is a struct btf_enum64 definition:
623 	 *
624 	 * const struct btf_enum64 {
625 	 *	__u32	name_off;
626 	 *	__u32	val_lo32;
627 	 *	__u32	val_hi32;
628 	 * };
629 	 */
630 	const __u32 *e64 = (const __u32 *)e;
631 
632 	return ((__u64)e64[2] << 32) | e64[1];
633 }
634 
635 static inline struct btf_member *btf_members(const struct btf_type *t)
636 {
637 	return (struct btf_member *)(t + 1);
638 }
639 
640 /* Get bit offset of a member with specified index. */
641 static inline __u32 btf_member_bit_offset(const struct btf_type *t,
642 					  __u32 member_idx)
643 {
644 	const struct btf_member *m = btf_members(t) + member_idx;
645 	bool kflag = btf_kflag(t);
646 
647 	return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
648 }
649 /*
650  * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
651  * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
652  */
653 static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
654 					     __u32 member_idx)
655 {
656 	const struct btf_member *m = btf_members(t) + member_idx;
657 	bool kflag = btf_kflag(t);
658 
659 	return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
660 }
661 
662 static inline struct btf_param *btf_params(const struct btf_type *t)
663 {
664 	return (struct btf_param *)(t + 1);
665 }
666 
667 static inline struct btf_var *btf_var(const struct btf_type *t)
668 {
669 	return (struct btf_var *)(t + 1);
670 }
671 
672 static inline struct btf_var_secinfo *
673 btf_var_secinfos(const struct btf_type *t)
674 {
675 	return (struct btf_var_secinfo *)(t + 1);
676 }
677 
678 struct btf_decl_tag;
679 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
680 {
681 	return (struct btf_decl_tag *)(t + 1);
682 }
683 
684 #ifdef __cplusplus
685 } /* extern "C" */
686 #endif
687 
688 #endif /* __LIBBPF_BTF_H */
689