1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 /* Copyright (c) 2018 Facebook */
10 #include <linux/btf.h>
11 #include <linux/types.h>
13 #include "libbpf_common.h"
19 #define BTF_ELF_SEC ".BTF"
20 #define BTF_EXT_ELF_SEC ".BTF.ext"
21 #define MAPS_ELF_SEC ".maps"
30 BTF_LITTLE_ENDIAN = 0,
35 * @brief **btf__free()** frees all data of a BTF object
36 * @param btf BTF object to free
38 LIBBPF_API void btf__free(struct btf *btf);
41 * @brief **btf__new()** creates a new instance of a BTF object from the raw
42 * bytes of an ELF's BTF section
43 * @param data raw bytes
44 * @param size number of bytes passed in `data`
45 * @return new BTF object instance which has to be eventually freed with
48 * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
49 * error code from such a pointer `libbpf_get_error()` should be used. If
50 * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
51 * returned on error instead. In both cases thread-local `errno` variable is
52 * always set to error code as well.
54 LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
57 * @brief **btf__new_split()** create a new instance of a BTF object from the
58 * provided raw data bytes. It takes another BTF instance, **base_btf**, which
59 * serves as a base BTF, which is extended by types in a newly created BTF
61 * @param data raw bytes
62 * @param size length of raw bytes
63 * @param base_btf the base BTF object
64 * @return new BTF object instance which has to be eventually freed with
67 * If *base_btf* is NULL, `btf__new_split()` is equivalent to `btf__new()` and
68 * creates non-split BTF.
70 * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
71 * error code from such a pointer `libbpf_get_error()` should be used. If
72 * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
73 * returned on error instead. In both cases thread-local `errno` variable is
74 * always set to error code as well.
76 LIBBPF_API struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf);
79 * @brief **btf__new_empty()** creates an empty BTF object. Use
80 * `btf__add_*()` to populate such BTF object.
81 * @return new BTF object instance which has to be eventually freed with
84 * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
85 * error code from such a pointer `libbpf_get_error()` should be used. If
86 * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
87 * returned on error instead. In both cases thread-local `errno` variable is
88 * always set to error code as well.
90 LIBBPF_API struct btf *btf__new_empty(void);
93 * @brief **btf__new_empty_split()** creates an unpopulated BTF object from an
94 * ELF BTF section except with a base BTF on top of which split BTF should be
96 * @return new BTF object instance which has to be eventually freed with
99 * If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to
100 * `btf__new_empty()` and creates non-split BTF.
102 * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
103 * error code from such a pointer `libbpf_get_error()` should be used. If
104 * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
105 * returned on error instead. In both cases thread-local `errno` variable is
106 * always set to error code as well.
108 LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
110 LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
111 LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
112 LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
113 LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf);
114 LIBBPF_API struct btf *btf__parse_raw(const char *path);
115 LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
117 LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
118 LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
120 LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
121 LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
123 LIBBPF_API int btf__load_into_kernel(struct btf *btf);
124 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
125 const char *type_name);
126 LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
127 const char *type_name, __u32 kind);
128 LIBBPF_API __u32 btf__type_cnt(const struct btf *btf);
129 LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf);
130 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
132 LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
133 LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
134 LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf);
135 LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian);
136 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
137 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
138 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
139 LIBBPF_API int btf__fd(const struct btf *btf);
140 LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
141 LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size);
142 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
143 LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
145 LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
146 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
147 LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
149 LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
150 LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
151 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
152 const struct btf_type *src_type);
154 * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
155 * @param btf BTF object which all the BTF types and strings are added to
156 * @param src_btf BTF object which all BTF types and referenced strings are copied from
157 * @return BTF type ID of the first appended BTF type, or negative error code
159 * **btf__add_btf()** can be used to simply and efficiently append the entire
160 * contents of one BTF object to another one. All the BTF type data is copied
161 * over, all referenced type IDs are adjusted by adding a necessary ID offset.
162 * Only strings referenced from BTF types are copied over and deduplicated, so
163 * if there were some unused strings in *src_btf*, those won't be copied over,
164 * which is consistent with the general string deduplication semantics of BTF
167 * If any error is encountered during this process, the contents of *btf* is
168 * left intact, which means that **btf__add_btf()** follows the transactional
169 * semantics and the operation as a whole is all-or-nothing.
171 * *src_btf* has to be non-split BTF, as of now copying types from split BTF
172 * is not supported and will result in -ENOTSUP error code returned.
174 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
176 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
177 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
178 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
179 LIBBPF_API int btf__add_array(struct btf *btf,
180 int index_type_id, int elem_type_id, __u32 nr_elems);
181 /* struct/union construction APIs */
182 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
183 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
184 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
185 __u32 bit_offset, __u32 bit_size);
187 /* enum construction APIs */
188 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
189 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
190 LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
191 LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
199 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
200 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
201 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
202 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
203 LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
204 LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
206 /* func and func_proto construction APIs */
207 LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
208 enum btf_func_linkage linkage, int proto_type_id);
209 LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
210 LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
212 /* var & datasec construction APIs */
213 LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
214 LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
215 LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
216 __u32 offset, __u32 byte_sz);
218 /* tag construction API */
219 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
222 struct btf_dedup_opts {
224 /* optional .BTF.ext info to dedup along the main BTF info */
225 struct btf_ext *btf_ext;
226 /* force hash collisions (used for testing) */
227 bool force_collisions;
230 #define btf_dedup_opts__last_field force_collisions
232 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
236 struct btf_dump_opts {
239 #define btf_dump_opts__last_field sz
241 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
243 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
244 btf_dump_printf_fn_t printf_fn,
246 const struct btf_dump_opts *opts);
248 LIBBPF_API void btf_dump__free(struct btf_dump *d);
250 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
252 struct btf_dump_emit_type_decl_opts {
253 /* size of this struct, for forward/backward compatiblity */
255 /* optional field name for type declaration, e.g.:
256 * - struct my_struct <FNAME>
257 * - void (*<FNAME>)(int)
258 * - char (*<FNAME>)[123]
260 const char *field_name;
261 /* extra indentation level (in number of tabs) to emit for multi-line
262 * type declarations (e.g., anonymous struct); applies for lines
263 * starting from the second one (first line is assumed to have
264 * necessary indentation already
267 /* strip all the const/volatile/restrict mods */
271 #define btf_dump_emit_type_decl_opts__last_field strip_mods
274 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
275 const struct btf_dump_emit_type_decl_opts *opts);
278 struct btf_dump_type_data_opts {
279 /* size of this struct, for forward/backward compatibility */
281 const char *indent_str;
283 /* below match "show" flags for bpf_show_snprintf() */
284 bool compact; /* no newlines/indentation */
285 bool skip_names; /* skip member/type names */
286 bool emit_zeroes; /* show 0-valued fields */
289 #define btf_dump_type_data_opts__last_field emit_zeroes
292 btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
293 const void *data, size_t data_sz,
294 const struct btf_dump_type_data_opts *opts);
297 * A set of helpers for easier BTF types handling.
299 * The inline functions below rely on constants from the kernel headers which
300 * may not be available for applications including this header file. To avoid
301 * compilation errors, we define all the constants here that were added after
302 * the initial introduction of the BTF_KIND* constants.
304 #ifndef BTF_KIND_FUNC
305 #define BTF_KIND_FUNC 12 /* Function */
306 #define BTF_KIND_FUNC_PROTO 13 /* Function Proto */
309 #define BTF_KIND_VAR 14 /* Variable */
310 #define BTF_KIND_DATASEC 15 /* Section */
312 #ifndef BTF_KIND_FLOAT
313 #define BTF_KIND_FLOAT 16 /* Floating point */
315 /* The kernel header switched to enums, so the following were never #defined */
316 #define BTF_KIND_DECL_TAG 17 /* Decl Tag */
317 #define BTF_KIND_TYPE_TAG 18 /* Type Tag */
318 #define BTF_KIND_ENUM64 19 /* Enum for up-to 64bit values */
320 static inline __u16 btf_kind(const struct btf_type *t)
322 return BTF_INFO_KIND(t->info);
325 static inline __u16 btf_vlen(const struct btf_type *t)
327 return BTF_INFO_VLEN(t->info);
330 static inline bool btf_kflag(const struct btf_type *t)
332 return BTF_INFO_KFLAG(t->info);
335 static inline bool btf_is_void(const struct btf_type *t)
337 return btf_kind(t) == BTF_KIND_UNKN;
340 static inline bool btf_is_int(const struct btf_type *t)
342 return btf_kind(t) == BTF_KIND_INT;
345 static inline bool btf_is_ptr(const struct btf_type *t)
347 return btf_kind(t) == BTF_KIND_PTR;
350 static inline bool btf_is_array(const struct btf_type *t)
352 return btf_kind(t) == BTF_KIND_ARRAY;
355 static inline bool btf_is_struct(const struct btf_type *t)
357 return btf_kind(t) == BTF_KIND_STRUCT;
360 static inline bool btf_is_union(const struct btf_type *t)
362 return btf_kind(t) == BTF_KIND_UNION;
365 static inline bool btf_is_composite(const struct btf_type *t)
367 __u16 kind = btf_kind(t);
369 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
372 static inline bool btf_is_enum(const struct btf_type *t)
374 return btf_kind(t) == BTF_KIND_ENUM;
377 static inline bool btf_is_enum64(const struct btf_type *t)
379 return btf_kind(t) == BTF_KIND_ENUM64;
382 static inline bool btf_is_fwd(const struct btf_type *t)
384 return btf_kind(t) == BTF_KIND_FWD;
387 static inline bool btf_is_typedef(const struct btf_type *t)
389 return btf_kind(t) == BTF_KIND_TYPEDEF;
392 static inline bool btf_is_volatile(const struct btf_type *t)
394 return btf_kind(t) == BTF_KIND_VOLATILE;
397 static inline bool btf_is_const(const struct btf_type *t)
399 return btf_kind(t) == BTF_KIND_CONST;
402 static inline bool btf_is_restrict(const struct btf_type *t)
404 return btf_kind(t) == BTF_KIND_RESTRICT;
407 static inline bool btf_is_mod(const struct btf_type *t)
409 __u16 kind = btf_kind(t);
411 return kind == BTF_KIND_VOLATILE ||
412 kind == BTF_KIND_CONST ||
413 kind == BTF_KIND_RESTRICT ||
414 kind == BTF_KIND_TYPE_TAG;
417 static inline bool btf_is_func(const struct btf_type *t)
419 return btf_kind(t) == BTF_KIND_FUNC;
422 static inline bool btf_is_func_proto(const struct btf_type *t)
424 return btf_kind(t) == BTF_KIND_FUNC_PROTO;
427 static inline bool btf_is_var(const struct btf_type *t)
429 return btf_kind(t) == BTF_KIND_VAR;
432 static inline bool btf_is_datasec(const struct btf_type *t)
434 return btf_kind(t) == BTF_KIND_DATASEC;
437 static inline bool btf_is_float(const struct btf_type *t)
439 return btf_kind(t) == BTF_KIND_FLOAT;
442 static inline bool btf_is_decl_tag(const struct btf_type *t)
444 return btf_kind(t) == BTF_KIND_DECL_TAG;
447 static inline bool btf_is_type_tag(const struct btf_type *t)
449 return btf_kind(t) == BTF_KIND_TYPE_TAG;
452 static inline bool btf_is_any_enum(const struct btf_type *t)
454 return btf_is_enum(t) || btf_is_enum64(t);
457 static inline bool btf_kind_core_compat(const struct btf_type *t1,
458 const struct btf_type *t2)
460 return btf_kind(t1) == btf_kind(t2) ||
461 (btf_is_any_enum(t1) && btf_is_any_enum(t2));
464 static inline __u8 btf_int_encoding(const struct btf_type *t)
466 return BTF_INT_ENCODING(*(__u32 *)(t + 1));
469 static inline __u8 btf_int_offset(const struct btf_type *t)
471 return BTF_INT_OFFSET(*(__u32 *)(t + 1));
474 static inline __u8 btf_int_bits(const struct btf_type *t)
476 return BTF_INT_BITS(*(__u32 *)(t + 1));
479 static inline struct btf_array *btf_array(const struct btf_type *t)
481 return (struct btf_array *)(t + 1);
484 static inline struct btf_enum *btf_enum(const struct btf_type *t)
486 return (struct btf_enum *)(t + 1);
491 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
493 return (struct btf_enum64 *)(t + 1);
496 static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
498 /* struct btf_enum64 is introduced in Linux 6.0, which is very
499 * bleeding-edge. Here we are avoiding relying on struct btf_enum64
500 * definition coming from kernel UAPI headers to support wider range
501 * of system-wide kernel headers.
503 * Given this header can be also included from C++ applications, that
504 * further restricts C tricks we can use (like using compatible
505 * anonymous struct). So just treat struct btf_enum64 as
506 * a three-element array of u32 and access second (lo32) and third
507 * (hi32) elements directly.
509 * For reference, here is a struct btf_enum64 definition:
511 * const struct btf_enum64 {
517 const __u32 *e64 = (const __u32 *)e;
519 return ((__u64)e64[2] << 32) | e64[1];
522 static inline struct btf_member *btf_members(const struct btf_type *t)
524 return (struct btf_member *)(t + 1);
527 /* Get bit offset of a member with specified index. */
528 static inline __u32 btf_member_bit_offset(const struct btf_type *t,
531 const struct btf_member *m = btf_members(t) + member_idx;
532 bool kflag = btf_kflag(t);
534 return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
537 * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
538 * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
540 static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
543 const struct btf_member *m = btf_members(t) + member_idx;
544 bool kflag = btf_kflag(t);
546 return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
549 static inline struct btf_param *btf_params(const struct btf_type *t)
551 return (struct btf_param *)(t + 1);
554 static inline struct btf_var *btf_var(const struct btf_type *t)
556 return (struct btf_var *)(t + 1);
559 static inline struct btf_var_secinfo *
560 btf_var_secinfos(const struct btf_type *t)
562 return (struct btf_var_secinfo *)(t + 1);
566 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
568 return (struct btf_decl_tag *)(t + 1);
575 #endif /* __LIBBPF_BTF_H */