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); 123 124 LIBBPF_API int btf__load_into_kernel(struct btf *btf); 125 LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, 126 const char *type_name); 127 LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf, 128 const char *type_name, __u32 kind); 129 LIBBPF_API __u32 btf__type_cnt(const struct btf *btf); 130 LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf); 131 LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf, 132 __u32 id); 133 LIBBPF_API size_t btf__pointer_size(const struct btf *btf); 134 LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz); 135 LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf); 136 LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian); 137 LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id); 138 LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id); 139 LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id); 140 LIBBPF_API int btf__fd(const struct btf *btf); 141 LIBBPF_API void btf__set_fd(struct btf *btf, int fd); 142 LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size); 143 LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset); 144 LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset); 145 146 LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size); 147 LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); 148 LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size); 149 150 LIBBPF_API int btf__find_str(struct btf *btf, const char *s); 151 LIBBPF_API int btf__add_str(struct btf *btf, const char *s); 152 LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf, 153 const struct btf_type *src_type); 154 /** 155 * @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf* 156 * @param btf BTF object which all the BTF types and strings are added to 157 * @param src_btf BTF object which all BTF types and referenced strings are copied from 158 * @return BTF type ID of the first appended BTF type, or negative error code 159 * 160 * **btf__add_btf()** can be used to simply and efficiently append the entire 161 * contents of one BTF object to another one. All the BTF type data is copied 162 * over, all referenced type IDs are adjusted by adding a necessary ID offset. 163 * Only strings referenced from BTF types are copied over and deduplicated, so 164 * if there were some unused strings in *src_btf*, those won't be copied over, 165 * which is consistent with the general string deduplication semantics of BTF 166 * writing APIs. 167 * 168 * If any error is encountered during this process, the contents of *btf* is 169 * left intact, which means that **btf__add_btf()** follows the transactional 170 * semantics and the operation as a whole is all-or-nothing. 171 * 172 * *src_btf* has to be non-split BTF, as of now copying types from split BTF 173 * is not supported and will result in -ENOTSUP error code returned. 174 */ 175 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf); 176 177 LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding); 178 LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz); 179 LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id); 180 LIBBPF_API int btf__add_array(struct btf *btf, 181 int index_type_id, int elem_type_id, __u32 nr_elems); 182 /* struct/union construction APIs */ 183 LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz); 184 LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz); 185 LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id, 186 __u32 bit_offset, __u32 bit_size); 187 188 /* enum construction APIs */ 189 LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz); 190 LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value); 191 LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed); 192 LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value); 193 194 enum btf_fwd_kind { 195 BTF_FWD_STRUCT = 0, 196 BTF_FWD_UNION = 1, 197 BTF_FWD_ENUM = 2, 198 }; 199 200 LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind); 201 LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id); 202 LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id); 203 LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id); 204 LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id); 205 LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id); 206 207 /* func and func_proto construction APIs */ 208 LIBBPF_API int btf__add_func(struct btf *btf, const char *name, 209 enum btf_func_linkage linkage, int proto_type_id); 210 LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id); 211 LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id); 212 213 /* var & datasec construction APIs */ 214 LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id); 215 LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz); 216 LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id, 217 __u32 offset, __u32 byte_sz); 218 219 /* tag construction API */ 220 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, 221 int component_idx); 222 223 struct btf_dedup_opts { 224 size_t sz; 225 /* optional .BTF.ext info to dedup along the main BTF info */ 226 struct btf_ext *btf_ext; 227 /* force hash collisions (used for testing) */ 228 bool force_collisions; 229 size_t :0; 230 }; 231 #define btf_dedup_opts__last_field force_collisions 232 233 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts); 234 235 struct btf_dump; 236 237 struct btf_dump_opts { 238 size_t sz; 239 }; 240 #define btf_dump_opts__last_field sz 241 242 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args); 243 244 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf, 245 btf_dump_printf_fn_t printf_fn, 246 void *ctx, 247 const struct btf_dump_opts *opts); 248 249 LIBBPF_API void btf_dump__free(struct btf_dump *d); 250 251 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); 252 253 struct btf_dump_emit_type_decl_opts { 254 /* size of this struct, for forward/backward compatiblity */ 255 size_t sz; 256 /* optional field name for type declaration, e.g.: 257 * - struct my_struct <FNAME> 258 * - void (*<FNAME>)(int) 259 * - char (*<FNAME>)[123] 260 */ 261 const char *field_name; 262 /* extra indentation level (in number of tabs) to emit for multi-line 263 * type declarations (e.g., anonymous struct); applies for lines 264 * starting from the second one (first line is assumed to have 265 * necessary indentation already 266 */ 267 int indent_level; 268 /* strip all the const/volatile/restrict mods */ 269 bool strip_mods; 270 size_t :0; 271 }; 272 #define btf_dump_emit_type_decl_opts__last_field strip_mods 273 274 LIBBPF_API int 275 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, 276 const struct btf_dump_emit_type_decl_opts *opts); 277 278 279 struct btf_dump_type_data_opts { 280 /* size of this struct, for forward/backward compatibility */ 281 size_t sz; 282 const char *indent_str; 283 int indent_level; 284 /* below match "show" flags for bpf_show_snprintf() */ 285 bool compact; /* no newlines/indentation */ 286 bool skip_names; /* skip member/type names */ 287 bool emit_zeroes; /* show 0-valued fields */ 288 size_t :0; 289 }; 290 #define btf_dump_type_data_opts__last_field emit_zeroes 291 292 LIBBPF_API int 293 btf_dump__dump_type_data(struct btf_dump *d, __u32 id, 294 const void *data, size_t data_sz, 295 const struct btf_dump_type_data_opts *opts); 296 297 /* 298 * A set of helpers for easier BTF types handling. 299 * 300 * The inline functions below rely on constants from the kernel headers which 301 * may not be available for applications including this header file. To avoid 302 * compilation errors, we define all the constants here that were added after 303 * the initial introduction of the BTF_KIND* constants. 304 */ 305 #ifndef BTF_KIND_FUNC 306 #define BTF_KIND_FUNC 12 /* Function */ 307 #define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ 308 #endif 309 #ifndef BTF_KIND_VAR 310 #define BTF_KIND_VAR 14 /* Variable */ 311 #define BTF_KIND_DATASEC 15 /* Section */ 312 #endif 313 #ifndef BTF_KIND_FLOAT 314 #define BTF_KIND_FLOAT 16 /* Floating point */ 315 #endif 316 /* The kernel header switched to enums, so the following were never #defined */ 317 #define BTF_KIND_DECL_TAG 17 /* Decl Tag */ 318 #define BTF_KIND_TYPE_TAG 18 /* Type Tag */ 319 #define BTF_KIND_ENUM64 19 /* Enum for up-to 64bit values */ 320 321 static inline __u16 btf_kind(const struct btf_type *t) 322 { 323 return BTF_INFO_KIND(t->info); 324 } 325 326 static inline __u16 btf_vlen(const struct btf_type *t) 327 { 328 return BTF_INFO_VLEN(t->info); 329 } 330 331 static inline bool btf_kflag(const struct btf_type *t) 332 { 333 return BTF_INFO_KFLAG(t->info); 334 } 335 336 static inline bool btf_is_void(const struct btf_type *t) 337 { 338 return btf_kind(t) == BTF_KIND_UNKN; 339 } 340 341 static inline bool btf_is_int(const struct btf_type *t) 342 { 343 return btf_kind(t) == BTF_KIND_INT; 344 } 345 346 static inline bool btf_is_ptr(const struct btf_type *t) 347 { 348 return btf_kind(t) == BTF_KIND_PTR; 349 } 350 351 static inline bool btf_is_array(const struct btf_type *t) 352 { 353 return btf_kind(t) == BTF_KIND_ARRAY; 354 } 355 356 static inline bool btf_is_struct(const struct btf_type *t) 357 { 358 return btf_kind(t) == BTF_KIND_STRUCT; 359 } 360 361 static inline bool btf_is_union(const struct btf_type *t) 362 { 363 return btf_kind(t) == BTF_KIND_UNION; 364 } 365 366 static inline bool btf_is_composite(const struct btf_type *t) 367 { 368 __u16 kind = btf_kind(t); 369 370 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; 371 } 372 373 static inline bool btf_is_enum(const struct btf_type *t) 374 { 375 return btf_kind(t) == BTF_KIND_ENUM; 376 } 377 378 static inline bool btf_is_enum64(const struct btf_type *t) 379 { 380 return btf_kind(t) == BTF_KIND_ENUM64; 381 } 382 383 static inline bool btf_is_fwd(const struct btf_type *t) 384 { 385 return btf_kind(t) == BTF_KIND_FWD; 386 } 387 388 static inline bool btf_is_typedef(const struct btf_type *t) 389 { 390 return btf_kind(t) == BTF_KIND_TYPEDEF; 391 } 392 393 static inline bool btf_is_volatile(const struct btf_type *t) 394 { 395 return btf_kind(t) == BTF_KIND_VOLATILE; 396 } 397 398 static inline bool btf_is_const(const struct btf_type *t) 399 { 400 return btf_kind(t) == BTF_KIND_CONST; 401 } 402 403 static inline bool btf_is_restrict(const struct btf_type *t) 404 { 405 return btf_kind(t) == BTF_KIND_RESTRICT; 406 } 407 408 static inline bool btf_is_mod(const struct btf_type *t) 409 { 410 __u16 kind = btf_kind(t); 411 412 return kind == BTF_KIND_VOLATILE || 413 kind == BTF_KIND_CONST || 414 kind == BTF_KIND_RESTRICT || 415 kind == BTF_KIND_TYPE_TAG; 416 } 417 418 static inline bool btf_is_func(const struct btf_type *t) 419 { 420 return btf_kind(t) == BTF_KIND_FUNC; 421 } 422 423 static inline bool btf_is_func_proto(const struct btf_type *t) 424 { 425 return btf_kind(t) == BTF_KIND_FUNC_PROTO; 426 } 427 428 static inline bool btf_is_var(const struct btf_type *t) 429 { 430 return btf_kind(t) == BTF_KIND_VAR; 431 } 432 433 static inline bool btf_is_datasec(const struct btf_type *t) 434 { 435 return btf_kind(t) == BTF_KIND_DATASEC; 436 } 437 438 static inline bool btf_is_float(const struct btf_type *t) 439 { 440 return btf_kind(t) == BTF_KIND_FLOAT; 441 } 442 443 static inline bool btf_is_decl_tag(const struct btf_type *t) 444 { 445 return btf_kind(t) == BTF_KIND_DECL_TAG; 446 } 447 448 static inline bool btf_is_type_tag(const struct btf_type *t) 449 { 450 return btf_kind(t) == BTF_KIND_TYPE_TAG; 451 } 452 453 static inline bool btf_is_any_enum(const struct btf_type *t) 454 { 455 return btf_is_enum(t) || btf_is_enum64(t); 456 } 457 458 static inline bool btf_kind_core_compat(const struct btf_type *t1, 459 const struct btf_type *t2) 460 { 461 return btf_kind(t1) == btf_kind(t2) || 462 (btf_is_any_enum(t1) && btf_is_any_enum(t2)); 463 } 464 465 static inline __u8 btf_int_encoding(const struct btf_type *t) 466 { 467 return BTF_INT_ENCODING(*(__u32 *)(t + 1)); 468 } 469 470 static inline __u8 btf_int_offset(const struct btf_type *t) 471 { 472 return BTF_INT_OFFSET(*(__u32 *)(t + 1)); 473 } 474 475 static inline __u8 btf_int_bits(const struct btf_type *t) 476 { 477 return BTF_INT_BITS(*(__u32 *)(t + 1)); 478 } 479 480 static inline struct btf_array *btf_array(const struct btf_type *t) 481 { 482 return (struct btf_array *)(t + 1); 483 } 484 485 static inline struct btf_enum *btf_enum(const struct btf_type *t) 486 { 487 return (struct btf_enum *)(t + 1); 488 } 489 490 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) 491 { 492 return (struct btf_enum64 *)(t + 1); 493 } 494 495 static inline __u64 btf_enum64_value(const struct btf_enum64 *e) 496 { 497 return ((__u64)e->val_hi32 << 32) | e->val_lo32; 498 } 499 500 static inline struct btf_member *btf_members(const struct btf_type *t) 501 { 502 return (struct btf_member *)(t + 1); 503 } 504 505 /* Get bit offset of a member with specified index. */ 506 static inline __u32 btf_member_bit_offset(const struct btf_type *t, 507 __u32 member_idx) 508 { 509 const struct btf_member *m = btf_members(t) + member_idx; 510 bool kflag = btf_kflag(t); 511 512 return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset; 513 } 514 /* 515 * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or 516 * BTF_KIND_UNION. If member is not a bitfield, zero is returned. 517 */ 518 static inline __u32 btf_member_bitfield_size(const struct btf_type *t, 519 __u32 member_idx) 520 { 521 const struct btf_member *m = btf_members(t) + member_idx; 522 bool kflag = btf_kflag(t); 523 524 return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0; 525 } 526 527 static inline struct btf_param *btf_params(const struct btf_type *t) 528 { 529 return (struct btf_param *)(t + 1); 530 } 531 532 static inline struct btf_var *btf_var(const struct btf_type *t) 533 { 534 return (struct btf_var *)(t + 1); 535 } 536 537 static inline struct btf_var_secinfo * 538 btf_var_secinfos(const struct btf_type *t) 539 { 540 return (struct btf_var_secinfo *)(t + 1); 541 } 542 543 struct btf_decl_tag; 544 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t) 545 { 546 return (struct btf_decl_tag *)(t + 1); 547 } 548 549 #ifdef __cplusplus 550 } /* extern "C" */ 551 #endif 552 553 #endif /* __LIBBPF_BTF_H */ 554