xref: /linux/tools/lib/bpf/btf.h (revision 3fd6c59042dbba50391e30862beac979491145fe)
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 LIBBPF_API enum btf_endianness btf_ext__endianness(const struct btf_ext *btf_ext);
171 LIBBPF_API int btf_ext__set_endianness(struct btf_ext *btf_ext,
172 				       enum btf_endianness endian);
173 
174 LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
175 LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
176 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
177 			     const struct btf_type *src_type);
178 /**
179  * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
180  * @param btf BTF object which all the BTF types and strings are added to
181  * @param src_btf BTF object which all BTF types and referenced strings are copied from
182  * @return BTF type ID of the first appended BTF type, or negative error code
183  *
184  * **btf__add_btf()** can be used to simply and efficiently append the entire
185  * contents of one BTF object to another one. All the BTF type data is copied
186  * over, all referenced type IDs are adjusted by adding a necessary ID offset.
187  * Only strings referenced from BTF types are copied over and deduplicated, so
188  * if there were some unused strings in *src_btf*, those won't be copied over,
189  * which is consistent with the general string deduplication semantics of BTF
190  * writing APIs.
191  *
192  * If any error is encountered during this process, the contents of *btf* is
193  * left intact, which means that **btf__add_btf()** follows the transactional
194  * semantics and the operation as a whole is all-or-nothing.
195  *
196  * *src_btf* has to be non-split BTF, as of now copying types from split BTF
197  * is not supported and will result in -ENOTSUP error code returned.
198  */
199 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
200 
201 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
202 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
203 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
204 LIBBPF_API int btf__add_array(struct btf *btf,
205 			      int index_type_id, int elem_type_id, __u32 nr_elems);
206 /* struct/union construction APIs */
207 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
208 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
209 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
210 			      __u32 bit_offset, __u32 bit_size);
211 
212 /* enum construction APIs */
213 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
214 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
215 LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
216 LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
217 
218 enum btf_fwd_kind {
219 	BTF_FWD_STRUCT = 0,
220 	BTF_FWD_UNION = 1,
221 	BTF_FWD_ENUM = 2,
222 };
223 
224 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
225 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
226 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
227 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
228 LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
229 LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
230 
231 /* func and func_proto construction APIs */
232 LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
233 			     enum btf_func_linkage linkage, int proto_type_id);
234 LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
235 LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
236 
237 /* var & datasec construction APIs */
238 LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
239 LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
240 LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
241 					 __u32 offset, __u32 byte_sz);
242 
243 /* tag construction API */
244 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
245 			    int component_idx);
246 
247 struct btf_dedup_opts {
248 	size_t sz;
249 	/* optional .BTF.ext info to dedup along the main BTF info */
250 	struct btf_ext *btf_ext;
251 	/* force hash collisions (used for testing) */
252 	bool force_collisions;
253 	size_t :0;
254 };
255 #define btf_dedup_opts__last_field force_collisions
256 
257 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
258 
259 /**
260  * @brief **btf__relocate()** will check the split BTF *btf* for references
261  * to base BTF kinds, and verify those references are compatible with
262  * *base_btf*; if they are, *btf* is adjusted such that is re-parented to
263  * *base_btf* and type ids and strings are adjusted to accommodate this.
264  *
265  * If successful, 0 is returned and **btf** now has **base_btf** as its
266  * base.
267  *
268  * A negative value is returned on error and the thread-local `errno` variable
269  * is set to the error code as well.
270  */
271 LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf);
272 
273 struct btf_dump;
274 
275 struct btf_dump_opts {
276 	size_t sz;
277 };
278 #define btf_dump_opts__last_field sz
279 
280 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
281 
282 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
283 					  btf_dump_printf_fn_t printf_fn,
284 					  void *ctx,
285 					  const struct btf_dump_opts *opts);
286 
287 LIBBPF_API void btf_dump__free(struct btf_dump *d);
288 
289 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
290 
291 struct btf_dump_emit_type_decl_opts {
292 	/* size of this struct, for forward/backward compatibility */
293 	size_t sz;
294 	/* optional field name for type declaration, e.g.:
295 	 * - struct my_struct <FNAME>
296 	 * - void (*<FNAME>)(int)
297 	 * - char (*<FNAME>)[123]
298 	 */
299 	const char *field_name;
300 	/* extra indentation level (in number of tabs) to emit for multi-line
301 	 * type declarations (e.g., anonymous struct); applies for lines
302 	 * starting from the second one (first line is assumed to have
303 	 * necessary indentation already
304 	 */
305 	int indent_level;
306 	/* strip all the const/volatile/restrict mods */
307 	bool strip_mods;
308 	size_t :0;
309 };
310 #define btf_dump_emit_type_decl_opts__last_field strip_mods
311 
312 LIBBPF_API int
313 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
314 			 const struct btf_dump_emit_type_decl_opts *opts);
315 
316 
317 struct btf_dump_type_data_opts {
318 	/* size of this struct, for forward/backward compatibility */
319 	size_t sz;
320 	const char *indent_str;
321 	int indent_level;
322 	/* below match "show" flags for bpf_show_snprintf() */
323 	bool compact;		/* no newlines/indentation */
324 	bool skip_names;	/* skip member/type names */
325 	bool emit_zeroes;	/* show 0-valued fields */
326 	size_t :0;
327 };
328 #define btf_dump_type_data_opts__last_field emit_zeroes
329 
330 LIBBPF_API int
331 btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
332 			 const void *data, size_t data_sz,
333 			 const struct btf_dump_type_data_opts *opts);
334 
335 /*
336  * A set of helpers for easier BTF types handling.
337  *
338  * The inline functions below rely on constants from the kernel headers which
339  * may not be available for applications including this header file. To avoid
340  * compilation errors, we define all the constants here that were added after
341  * the initial introduction of the BTF_KIND* constants.
342  */
343 #ifndef BTF_KIND_FUNC
344 #define BTF_KIND_FUNC		12	/* Function	*/
345 #define BTF_KIND_FUNC_PROTO	13	/* Function Proto	*/
346 #endif
347 #ifndef BTF_KIND_VAR
348 #define BTF_KIND_VAR		14	/* Variable	*/
349 #define BTF_KIND_DATASEC	15	/* Section	*/
350 #endif
351 #ifndef BTF_KIND_FLOAT
352 #define BTF_KIND_FLOAT		16	/* Floating point	*/
353 #endif
354 /* The kernel header switched to enums, so the following were never #defined */
355 #define BTF_KIND_DECL_TAG	17	/* Decl Tag */
356 #define BTF_KIND_TYPE_TAG	18	/* Type Tag */
357 #define BTF_KIND_ENUM64		19	/* Enum for up-to 64bit values */
358 
btf_kind(const struct btf_type * t)359 static inline __u16 btf_kind(const struct btf_type *t)
360 {
361 	return BTF_INFO_KIND(t->info);
362 }
363 
btf_vlen(const struct btf_type * t)364 static inline __u16 btf_vlen(const struct btf_type *t)
365 {
366 	return BTF_INFO_VLEN(t->info);
367 }
368 
btf_kflag(const struct btf_type * t)369 static inline bool btf_kflag(const struct btf_type *t)
370 {
371 	return BTF_INFO_KFLAG(t->info);
372 }
373 
btf_is_void(const struct btf_type * t)374 static inline bool btf_is_void(const struct btf_type *t)
375 {
376 	return btf_kind(t) == BTF_KIND_UNKN;
377 }
378 
btf_is_int(const struct btf_type * t)379 static inline bool btf_is_int(const struct btf_type *t)
380 {
381 	return btf_kind(t) == BTF_KIND_INT;
382 }
383 
btf_is_ptr(const struct btf_type * t)384 static inline bool btf_is_ptr(const struct btf_type *t)
385 {
386 	return btf_kind(t) == BTF_KIND_PTR;
387 }
388 
btf_is_array(const struct btf_type * t)389 static inline bool btf_is_array(const struct btf_type *t)
390 {
391 	return btf_kind(t) == BTF_KIND_ARRAY;
392 }
393 
btf_is_struct(const struct btf_type * t)394 static inline bool btf_is_struct(const struct btf_type *t)
395 {
396 	return btf_kind(t) == BTF_KIND_STRUCT;
397 }
398 
btf_is_union(const struct btf_type * t)399 static inline bool btf_is_union(const struct btf_type *t)
400 {
401 	return btf_kind(t) == BTF_KIND_UNION;
402 }
403 
btf_is_composite(const struct btf_type * t)404 static inline bool btf_is_composite(const struct btf_type *t)
405 {
406 	__u16 kind = btf_kind(t);
407 
408 	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
409 }
410 
btf_is_enum(const struct btf_type * t)411 static inline bool btf_is_enum(const struct btf_type *t)
412 {
413 	return btf_kind(t) == BTF_KIND_ENUM;
414 }
415 
btf_is_enum64(const struct btf_type * t)416 static inline bool btf_is_enum64(const struct btf_type *t)
417 {
418 	return btf_kind(t) == BTF_KIND_ENUM64;
419 }
420 
btf_is_fwd(const struct btf_type * t)421 static inline bool btf_is_fwd(const struct btf_type *t)
422 {
423 	return btf_kind(t) == BTF_KIND_FWD;
424 }
425 
btf_is_typedef(const struct btf_type * t)426 static inline bool btf_is_typedef(const struct btf_type *t)
427 {
428 	return btf_kind(t) == BTF_KIND_TYPEDEF;
429 }
430 
btf_is_volatile(const struct btf_type * t)431 static inline bool btf_is_volatile(const struct btf_type *t)
432 {
433 	return btf_kind(t) == BTF_KIND_VOLATILE;
434 }
435 
btf_is_const(const struct btf_type * t)436 static inline bool btf_is_const(const struct btf_type *t)
437 {
438 	return btf_kind(t) == BTF_KIND_CONST;
439 }
440 
btf_is_restrict(const struct btf_type * t)441 static inline bool btf_is_restrict(const struct btf_type *t)
442 {
443 	return btf_kind(t) == BTF_KIND_RESTRICT;
444 }
445 
btf_is_mod(const struct btf_type * t)446 static inline bool btf_is_mod(const struct btf_type *t)
447 {
448 	__u16 kind = btf_kind(t);
449 
450 	return kind == BTF_KIND_VOLATILE ||
451 	       kind == BTF_KIND_CONST ||
452 	       kind == BTF_KIND_RESTRICT ||
453 	       kind == BTF_KIND_TYPE_TAG;
454 }
455 
btf_is_func(const struct btf_type * t)456 static inline bool btf_is_func(const struct btf_type *t)
457 {
458 	return btf_kind(t) == BTF_KIND_FUNC;
459 }
460 
btf_is_func_proto(const struct btf_type * t)461 static inline bool btf_is_func_proto(const struct btf_type *t)
462 {
463 	return btf_kind(t) == BTF_KIND_FUNC_PROTO;
464 }
465 
btf_is_var(const struct btf_type * t)466 static inline bool btf_is_var(const struct btf_type *t)
467 {
468 	return btf_kind(t) == BTF_KIND_VAR;
469 }
470 
btf_is_datasec(const struct btf_type * t)471 static inline bool btf_is_datasec(const struct btf_type *t)
472 {
473 	return btf_kind(t) == BTF_KIND_DATASEC;
474 }
475 
btf_is_float(const struct btf_type * t)476 static inline bool btf_is_float(const struct btf_type *t)
477 {
478 	return btf_kind(t) == BTF_KIND_FLOAT;
479 }
480 
btf_is_decl_tag(const struct btf_type * t)481 static inline bool btf_is_decl_tag(const struct btf_type *t)
482 {
483 	return btf_kind(t) == BTF_KIND_DECL_TAG;
484 }
485 
btf_is_type_tag(const struct btf_type * t)486 static inline bool btf_is_type_tag(const struct btf_type *t)
487 {
488 	return btf_kind(t) == BTF_KIND_TYPE_TAG;
489 }
490 
btf_is_any_enum(const struct btf_type * t)491 static inline bool btf_is_any_enum(const struct btf_type *t)
492 {
493 	return btf_is_enum(t) || btf_is_enum64(t);
494 }
495 
btf_kind_core_compat(const struct btf_type * t1,const struct btf_type * t2)496 static inline bool btf_kind_core_compat(const struct btf_type *t1,
497 					const struct btf_type *t2)
498 {
499 	return btf_kind(t1) == btf_kind(t2) ||
500 	       (btf_is_any_enum(t1) && btf_is_any_enum(t2));
501 }
502 
btf_int_encoding(const struct btf_type * t)503 static inline __u8 btf_int_encoding(const struct btf_type *t)
504 {
505 	return BTF_INT_ENCODING(*(__u32 *)(t + 1));
506 }
507 
btf_int_offset(const struct btf_type * t)508 static inline __u8 btf_int_offset(const struct btf_type *t)
509 {
510 	return BTF_INT_OFFSET(*(__u32 *)(t + 1));
511 }
512 
btf_int_bits(const struct btf_type * t)513 static inline __u8 btf_int_bits(const struct btf_type *t)
514 {
515 	return BTF_INT_BITS(*(__u32 *)(t + 1));
516 }
517 
btf_array(const struct btf_type * t)518 static inline struct btf_array *btf_array(const struct btf_type *t)
519 {
520 	return (struct btf_array *)(t + 1);
521 }
522 
btf_enum(const struct btf_type * t)523 static inline struct btf_enum *btf_enum(const struct btf_type *t)
524 {
525 	return (struct btf_enum *)(t + 1);
526 }
527 
528 struct btf_enum64;
529 
btf_enum64(const struct btf_type * t)530 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
531 {
532 	return (struct btf_enum64 *)(t + 1);
533 }
534 
btf_enum64_value(const struct btf_enum64 * e)535 static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
536 {
537 	/* struct btf_enum64 is introduced in Linux 6.0, which is very
538 	 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
539 	 * definition coming from kernel UAPI headers to support wider range
540 	 * of system-wide kernel headers.
541 	 *
542 	 * Given this header can be also included from C++ applications, that
543 	 * further restricts C tricks we can use (like using compatible
544 	 * anonymous struct). So just treat struct btf_enum64 as
545 	 * a three-element array of u32 and access second (lo32) and third
546 	 * (hi32) elements directly.
547 	 *
548 	 * For reference, here is a struct btf_enum64 definition:
549 	 *
550 	 * const struct btf_enum64 {
551 	 *	__u32	name_off;
552 	 *	__u32	val_lo32;
553 	 *	__u32	val_hi32;
554 	 * };
555 	 */
556 	const __u32 *e64 = (const __u32 *)e;
557 
558 	return ((__u64)e64[2] << 32) | e64[1];
559 }
560 
btf_members(const struct btf_type * t)561 static inline struct btf_member *btf_members(const struct btf_type *t)
562 {
563 	return (struct btf_member *)(t + 1);
564 }
565 
566 /* Get bit offset of a member with specified index. */
btf_member_bit_offset(const struct btf_type * t,__u32 member_idx)567 static inline __u32 btf_member_bit_offset(const struct btf_type *t,
568 					  __u32 member_idx)
569 {
570 	const struct btf_member *m = btf_members(t) + member_idx;
571 	bool kflag = btf_kflag(t);
572 
573 	return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
574 }
575 /*
576  * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
577  * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
578  */
btf_member_bitfield_size(const struct btf_type * t,__u32 member_idx)579 static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
580 					     __u32 member_idx)
581 {
582 	const struct btf_member *m = btf_members(t) + member_idx;
583 	bool kflag = btf_kflag(t);
584 
585 	return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
586 }
587 
btf_params(const struct btf_type * t)588 static inline struct btf_param *btf_params(const struct btf_type *t)
589 {
590 	return (struct btf_param *)(t + 1);
591 }
592 
btf_var(const struct btf_type * t)593 static inline struct btf_var *btf_var(const struct btf_type *t)
594 {
595 	return (struct btf_var *)(t + 1);
596 }
597 
598 static inline struct btf_var_secinfo *
btf_var_secinfos(const struct btf_type * t)599 btf_var_secinfos(const struct btf_type *t)
600 {
601 	return (struct btf_var_secinfo *)(t + 1);
602 }
603 
604 struct btf_decl_tag;
btf_decl_tag(const struct btf_type * t)605 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
606 {
607 	return (struct btf_decl_tag *)(t + 1);
608 }
609 
610 #ifdef __cplusplus
611 } /* extern "C" */
612 #endif
613 
614 #endif /* __LIBBPF_BTF_H */
615