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 MAPS_ELF_SEC ".maps" 22 23 struct btf; 24 struct btf_ext; 25 struct btf_type; 26 27 struct bpf_object; 28 29 enum btf_endianness { 30 BTF_LITTLE_ENDIAN = 0, 31 BTF_BIG_ENDIAN = 1, 32 }; 33 34 /** 35 * @brief **btf__free()** frees all data of a BTF object 36 * @param btf BTF object to free 37 */ 38 LIBBPF_API void btf__free(struct btf *btf); 39 40 /** 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 46 * **btf__free()** 47 * 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. 53 */ 54 LIBBPF_API struct btf *btf__new(const void *data, __u32 size); 55 56 /** 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 60 * instance 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 65 * **btf__free()** 66 * 67 * If *base_btf* is NULL, `btf__new_split()` is equivalent to `btf__new()` and 68 * creates non-split BTF. 69 * 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. 75 */ 76 LIBBPF_API struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf); 77 78 /** 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 82 * **btf__free()** 83 * 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. 89 */ 90 LIBBPF_API struct btf *btf__new_empty(void); 91 92 /** 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 95 * based 96 * @return new BTF object instance which has to be eventually freed with 97 * **btf__free()** 98 * 99 * If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to 100 * `btf__new_empty()` and creates non-split BTF. 101 * 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. 107 */ 108 LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf); 109 110 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); 116 117 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); 119 LIBBPF_API struct btf *libbpf_find_kernel_btf(void); 120 121 LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id); 122 LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf); 123 LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_from_kernel_by_id instead") 124 LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); 125 126 LIBBPF_DEPRECATED_SINCE(0, 6, "intended for internal libbpf use only") 127 LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf); 128 LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_into_kernel instead") 129 LIBBPF_API int btf__load(struct btf *btf); 130 LIBBPF_API int btf__load_into_kernel(struct btf *btf); 131 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, 132 const char *type_name); 133 LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf, 134 const char *type_name, __u32 kind); 135 LIBBPF_DEPRECATED_SINCE(0, 7, "use btf__type_cnt() instead; note that btf__get_nr_types() == btf__type_cnt() - 1") 136 LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf); 137 LIBBPF_API __u32 btf__type_cnt(const struct btf *btf); 138 LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf); 139 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, 140 __u32 id); 141 LIBBPF_API size_t btf__pointer_size(const struct btf *btf); 142 LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz); 143 LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf); 144 LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian); 145 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); 146 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); 147 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); 148 LIBBPF_API int btf__fd(const struct btf *btf); 149 LIBBPF_API void btf__set_fd(struct btf *btf, int fd); 150 LIBBPF_DEPRECATED_SINCE(0, 7, "use btf__raw_data() instead") 151 LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size); 152 LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size); 153 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); 154 LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset); 155 LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, 156 __u32 expected_key_size, 157 __u32 expected_value_size, 158 __u32 *key_type_id, __u32 *value_type_id); 159 160 LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); 161 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); 162 LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, 163 __u32 *size); 164 LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_func_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") 165 int btf_ext__reloc_func_info(const struct btf *btf, 166 const struct btf_ext *btf_ext, 167 const char *sec_name, __u32 insns_cnt, 168 void **func_info, __u32 *cnt); 169 LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_line_info was never meant as a public API and has wrong assumptions embedded in it; it will be removed in the future libbpf versions") 170 int btf_ext__reloc_line_info(const struct btf *btf, 171 const struct btf_ext *btf_ext, 172 const char *sec_name, __u32 insns_cnt, 173 void **line_info, __u32 *cnt); 174 LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext); 175 LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext); 176 177 LIBBPF_API int btf__find_str(struct btf *btf, const char *s); 178 LIBBPF_API int btf__add_str(struct btf *btf, const char *s); 179 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf, 180 const struct btf_type *src_type); 181 /** 182 * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf* 183 * @param btf BTF object which all the BTF types and strings are added to 184 * @param src_btf BTF object which all BTF types and referenced strings are copied from 185 * @return BTF type ID of the first appended BTF type, or negative error code 186 * 187 * **btf__add_btf()** can be used to simply and efficiently append the entire 188 * contents of one BTF object to another one. All the BTF type data is copied 189 * over, all referenced type IDs are adjusted by adding a necessary ID offset. 190 * Only strings referenced from BTF types are copied over and deduplicated, so 191 * if there were some unused strings in *src_btf*, those won't be copied over, 192 * which is consistent with the general string deduplication semantics of BTF 193 * writing APIs. 194 * 195 * If any error is encountered during this process, the contents of *btf* is 196 * left intact, which means that **btf__add_btf()** follows the transactional 197 * semantics and the operation as a whole is all-or-nothing. 198 * 199 * *src_btf* has to be non-split BTF, as of now copying types from split BTF 200 * is not supported and will result in -ENOTSUP error code returned. 201 */ 202 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf); 203 204 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); 205 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz); 206 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); 207 LIBBPF_API int btf__add_array(struct btf *btf, 208 int index_type_id, int elem_type_id, __u32 nr_elems); 209 /* struct/union construction APIs */ 210 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz); 211 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz); 212 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id, 213 __u32 bit_offset, __u32 bit_size); 214 215 /* enum construction APIs */ 216 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz); 217 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value); 218 219 enum btf_fwd_kind { 220 BTF_FWD_STRUCT = 0, 221 BTF_FWD_UNION = 1, 222 BTF_FWD_ENUM = 2, 223 }; 224 225 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind); 226 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id); 227 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); 228 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); 229 LIBBPF_API int btf__add_restrict(struct btf *btf, 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 unsigned int dedup_table_size; 249 bool dont_resolve_fwds; 250 }; 251 252 LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext, 253 const struct btf_dedup_opts *opts); 254 255 struct btf_dump; 256 257 struct btf_dump_opts { 258 void *ctx; 259 }; 260 261 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args); 262 263 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf, 264 const struct btf_ext *btf_ext, 265 const struct btf_dump_opts *opts, 266 btf_dump_printf_fn_t printf_fn); 267 LIBBPF_API void btf_dump__free(struct btf_dump *d); 268 269 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); 270 271 struct btf_dump_emit_type_decl_opts { 272 /* size of this struct, for forward/backward compatiblity */ 273 size_t sz; 274 /* optional field name for type declaration, e.g.: 275 * - struct my_struct <FNAME> 276 * - void (*<FNAME>)(int) 277 * - char (*<FNAME>)[123] 278 */ 279 const char *field_name; 280 /* extra indentation level (in number of tabs) to emit for multi-line 281 * type declarations (e.g., anonymous struct); applies for lines 282 * starting from the second one (first line is assumed to have 283 * necessary indentation already 284 */ 285 int indent_level; 286 /* strip all the const/volatile/restrict mods */ 287 bool strip_mods; 288 size_t :0; 289 }; 290 #define btf_dump_emit_type_decl_opts__last_field strip_mods 291 292 LIBBPF_API int 293 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, 294 const struct btf_dump_emit_type_decl_opts *opts); 295 296 297 struct btf_dump_type_data_opts { 298 /* size of this struct, for forward/backward compatibility */ 299 size_t sz; 300 const char *indent_str; 301 int indent_level; 302 /* below match "show" flags for bpf_show_snprintf() */ 303 bool compact; /* no newlines/indentation */ 304 bool skip_names; /* skip member/type names */ 305 bool emit_zeroes; /* show 0-valued fields */ 306 size_t :0; 307 }; 308 #define btf_dump_type_data_opts__last_field emit_zeroes 309 310 LIBBPF_API int 311 btf_dump__dump_type_data(struct btf_dump *d, __u32 id, 312 const void *data, size_t data_sz, 313 const struct btf_dump_type_data_opts *opts); 314 315 /* 316 * A set of helpers for easier BTF types handling 317 */ 318 static inline __u16 btf_kind(const struct btf_type *t) 319 { 320 return BTF_INFO_KIND(t->info); 321 } 322 323 static inline __u16 btf_vlen(const struct btf_type *t) 324 { 325 return BTF_INFO_VLEN(t->info); 326 } 327 328 static inline bool btf_kflag(const struct btf_type *t) 329 { 330 return BTF_INFO_KFLAG(t->info); 331 } 332 333 static inline bool btf_is_void(const struct btf_type *t) 334 { 335 return btf_kind(t) == BTF_KIND_UNKN; 336 } 337 338 static inline bool btf_is_int(const struct btf_type *t) 339 { 340 return btf_kind(t) == BTF_KIND_INT; 341 } 342 343 static inline bool btf_is_ptr(const struct btf_type *t) 344 { 345 return btf_kind(t) == BTF_KIND_PTR; 346 } 347 348 static inline bool btf_is_array(const struct btf_type *t) 349 { 350 return btf_kind(t) == BTF_KIND_ARRAY; 351 } 352 353 static inline bool btf_is_struct(const struct btf_type *t) 354 { 355 return btf_kind(t) == BTF_KIND_STRUCT; 356 } 357 358 static inline bool btf_is_union(const struct btf_type *t) 359 { 360 return btf_kind(t) == BTF_KIND_UNION; 361 } 362 363 static inline bool btf_is_composite(const struct btf_type *t) 364 { 365 __u16 kind = btf_kind(t); 366 367 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; 368 } 369 370 static inline bool btf_is_enum(const struct btf_type *t) 371 { 372 return btf_kind(t) == BTF_KIND_ENUM; 373 } 374 375 static inline bool btf_is_fwd(const struct btf_type *t) 376 { 377 return btf_kind(t) == BTF_KIND_FWD; 378 } 379 380 static inline bool btf_is_typedef(const struct btf_type *t) 381 { 382 return btf_kind(t) == BTF_KIND_TYPEDEF; 383 } 384 385 static inline bool btf_is_volatile(const struct btf_type *t) 386 { 387 return btf_kind(t) == BTF_KIND_VOLATILE; 388 } 389 390 static inline bool btf_is_const(const struct btf_type *t) 391 { 392 return btf_kind(t) == BTF_KIND_CONST; 393 } 394 395 static inline bool btf_is_restrict(const struct btf_type *t) 396 { 397 return btf_kind(t) == BTF_KIND_RESTRICT; 398 } 399 400 static inline bool btf_is_mod(const struct btf_type *t) 401 { 402 __u16 kind = btf_kind(t); 403 404 return kind == BTF_KIND_VOLATILE || 405 kind == BTF_KIND_CONST || 406 kind == BTF_KIND_RESTRICT; 407 } 408 409 static inline bool btf_is_func(const struct btf_type *t) 410 { 411 return btf_kind(t) == BTF_KIND_FUNC; 412 } 413 414 static inline bool btf_is_func_proto(const struct btf_type *t) 415 { 416 return btf_kind(t) == BTF_KIND_FUNC_PROTO; 417 } 418 419 static inline bool btf_is_var(const struct btf_type *t) 420 { 421 return btf_kind(t) == BTF_KIND_VAR; 422 } 423 424 static inline bool btf_is_datasec(const struct btf_type *t) 425 { 426 return btf_kind(t) == BTF_KIND_DATASEC; 427 } 428 429 static inline bool btf_is_float(const struct btf_type *t) 430 { 431 return btf_kind(t) == BTF_KIND_FLOAT; 432 } 433 434 static inline bool btf_is_decl_tag(const struct btf_type *t) 435 { 436 return btf_kind(t) == BTF_KIND_DECL_TAG; 437 } 438 439 static inline __u8 btf_int_encoding(const struct btf_type *t) 440 { 441 return BTF_INT_ENCODING(*(__u32 *)(t + 1)); 442 } 443 444 static inline __u8 btf_int_offset(const struct btf_type *t) 445 { 446 return BTF_INT_OFFSET(*(__u32 *)(t + 1)); 447 } 448 449 static inline __u8 btf_int_bits(const struct btf_type *t) 450 { 451 return BTF_INT_BITS(*(__u32 *)(t + 1)); 452 } 453 454 static inline struct btf_array *btf_array(const struct btf_type *t) 455 { 456 return (struct btf_array *)(t + 1); 457 } 458 459 static inline struct btf_enum *btf_enum(const struct btf_type *t) 460 { 461 return (struct btf_enum *)(t + 1); 462 } 463 464 static inline struct btf_member *btf_members(const struct btf_type *t) 465 { 466 return (struct btf_member *)(t + 1); 467 } 468 469 /* Get bit offset of a member with specified index. */ 470 static inline __u32 btf_member_bit_offset(const struct btf_type *t, 471 __u32 member_idx) 472 { 473 const struct btf_member *m = btf_members(t) + member_idx; 474 bool kflag = btf_kflag(t); 475 476 return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset; 477 } 478 /* 479 * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or 480 * BTF_KIND_UNION. If member is not a bitfield, zero is returned. 481 */ 482 static inline __u32 btf_member_bitfield_size(const struct btf_type *t, 483 __u32 member_idx) 484 { 485 const struct btf_member *m = btf_members(t) + member_idx; 486 bool kflag = btf_kflag(t); 487 488 return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0; 489 } 490 491 static inline struct btf_param *btf_params(const struct btf_type *t) 492 { 493 return (struct btf_param *)(t + 1); 494 } 495 496 static inline struct btf_var *btf_var(const struct btf_type *t) 497 { 498 return (struct btf_var *)(t + 1); 499 } 500 501 static inline struct btf_var_secinfo * 502 btf_var_secinfos(const struct btf_type *t) 503 { 504 return (struct btf_var_secinfo *)(t + 1); 505 } 506 507 struct btf_decl_tag; 508 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t) 509 { 510 return (struct btf_decl_tag *)(t + 1); 511 } 512 513 #ifdef __cplusplus 514 } /* extern "C" */ 515 #endif 516 517 #endif /* __LIBBPF_BTF_H */ 518