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); 119 120 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); 122 123 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, 131 __u32 id); 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); 144 145 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); 148 149 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); 153 /** 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 158 * 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 165 * writing APIs. 166 * 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. 170 * 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. 173 */ 174 LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf); 175 176 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); 186 187 /* 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); 192 193 enum btf_fwd_kind { 194 BTF_FWD_STRUCT = 0, 195 BTF_FWD_UNION = 1, 196 BTF_FWD_ENUM = 2, 197 }; 198 199 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); 205 206 /* 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); 211 212 /* 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); 217 218 /* tag construction API */ 219 LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id, 220 int component_idx); 221 222 struct btf_dedup_opts { 223 size_t sz; 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; 228 size_t :0; 229 }; 230 #define btf_dedup_opts__last_field force_collisions 231 232 LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts); 233 234 struct btf_dump; 235 236 struct btf_dump_opts { 237 size_t sz; 238 }; 239 #define btf_dump_opts__last_field sz 240 241 typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args); 242 243 LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf, 244 btf_dump_printf_fn_t printf_fn, 245 void *ctx, 246 const struct btf_dump_opts *opts); 247 248 LIBBPF_API void btf_dump__free(struct btf_dump *d); 249 250 LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id); 251 252 struct btf_dump_emit_type_decl_opts { 253 /* size of this struct, for forward/backward compatiblity */ 254 size_t sz; 255 /* optional field name for type declaration, e.g.: 256 * - struct my_struct <FNAME> 257 * - void (*<FNAME>)(int) 258 * - char (*<FNAME>)[123] 259 */ 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 265 */ 266 int indent_level; 267 /* strip all the const/volatile/restrict mods */ 268 bool strip_mods; 269 size_t :0; 270 }; 271 #define btf_dump_emit_type_decl_opts__last_field strip_mods 272 273 LIBBPF_API int 274 btf_dump__emit_type_decl(struct btf_dump *d, __u32 id, 275 const struct btf_dump_emit_type_decl_opts *opts); 276 277 278 struct btf_dump_type_data_opts { 279 /* size of this struct, for forward/backward compatibility */ 280 size_t sz; 281 const char *indent_str; 282 int indent_level; 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 */ 287 size_t :0; 288 }; 289 #define btf_dump_type_data_opts__last_field emit_zeroes 290 291 LIBBPF_API int 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); 295 296 /* 297 * A set of helpers for easier BTF types handling. 298 * 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. 303 */ 304 #ifndef BTF_KIND_FUNC 305 #define BTF_KIND_FUNC 12 /* Function */ 306 #define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ 307 #endif 308 #ifndef BTF_KIND_VAR 309 #define BTF_KIND_VAR 14 /* Variable */ 310 #define BTF_KIND_DATASEC 15 /* Section */ 311 #endif 312 #ifndef BTF_KIND_FLOAT 313 #define BTF_KIND_FLOAT 16 /* Floating point */ 314 #endif 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 */ 319 320 static inline __u16 btf_kind(const struct btf_type *t) 321 { 322 return BTF_INFO_KIND(t->info); 323 } 324 325 static inline __u16 btf_vlen(const struct btf_type *t) 326 { 327 return BTF_INFO_VLEN(t->info); 328 } 329 330 static inline bool btf_kflag(const struct btf_type *t) 331 { 332 return BTF_INFO_KFLAG(t->info); 333 } 334 335 static inline bool btf_is_void(const struct btf_type *t) 336 { 337 return btf_kind(t) == BTF_KIND_UNKN; 338 } 339 340 static inline bool btf_is_int(const struct btf_type *t) 341 { 342 return btf_kind(t) == BTF_KIND_INT; 343 } 344 345 static inline bool btf_is_ptr(const struct btf_type *t) 346 { 347 return btf_kind(t) == BTF_KIND_PTR; 348 } 349 350 static inline bool btf_is_array(const struct btf_type *t) 351 { 352 return btf_kind(t) == BTF_KIND_ARRAY; 353 } 354 355 static inline bool btf_is_struct(const struct btf_type *t) 356 { 357 return btf_kind(t) == BTF_KIND_STRUCT; 358 } 359 360 static inline bool btf_is_union(const struct btf_type *t) 361 { 362 return btf_kind(t) == BTF_KIND_UNION; 363 } 364 365 static inline bool btf_is_composite(const struct btf_type *t) 366 { 367 __u16 kind = btf_kind(t); 368 369 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; 370 } 371 372 static inline bool btf_is_enum(const struct btf_type *t) 373 { 374 return btf_kind(t) == BTF_KIND_ENUM; 375 } 376 377 static inline bool btf_is_enum64(const struct btf_type *t) 378 { 379 return btf_kind(t) == BTF_KIND_ENUM64; 380 } 381 382 static inline bool btf_is_fwd(const struct btf_type *t) 383 { 384 return btf_kind(t) == BTF_KIND_FWD; 385 } 386 387 static inline bool btf_is_typedef(const struct btf_type *t) 388 { 389 return btf_kind(t) == BTF_KIND_TYPEDEF; 390 } 391 392 static inline bool btf_is_volatile(const struct btf_type *t) 393 { 394 return btf_kind(t) == BTF_KIND_VOLATILE; 395 } 396 397 static inline bool btf_is_const(const struct btf_type *t) 398 { 399 return btf_kind(t) == BTF_KIND_CONST; 400 } 401 402 static inline bool btf_is_restrict(const struct btf_type *t) 403 { 404 return btf_kind(t) == BTF_KIND_RESTRICT; 405 } 406 407 static inline bool btf_is_mod(const struct btf_type *t) 408 { 409 __u16 kind = btf_kind(t); 410 411 return kind == BTF_KIND_VOLATILE || 412 kind == BTF_KIND_CONST || 413 kind == BTF_KIND_RESTRICT || 414 kind == BTF_KIND_TYPE_TAG; 415 } 416 417 static inline bool btf_is_func(const struct btf_type *t) 418 { 419 return btf_kind(t) == BTF_KIND_FUNC; 420 } 421 422 static inline bool btf_is_func_proto(const struct btf_type *t) 423 { 424 return btf_kind(t) == BTF_KIND_FUNC_PROTO; 425 } 426 427 static inline bool btf_is_var(const struct btf_type *t) 428 { 429 return btf_kind(t) == BTF_KIND_VAR; 430 } 431 432 static inline bool btf_is_datasec(const struct btf_type *t) 433 { 434 return btf_kind(t) == BTF_KIND_DATASEC; 435 } 436 437 static inline bool btf_is_float(const struct btf_type *t) 438 { 439 return btf_kind(t) == BTF_KIND_FLOAT; 440 } 441 442 static inline bool btf_is_decl_tag(const struct btf_type *t) 443 { 444 return btf_kind(t) == BTF_KIND_DECL_TAG; 445 } 446 447 static inline bool btf_is_type_tag(const struct btf_type *t) 448 { 449 return btf_kind(t) == BTF_KIND_TYPE_TAG; 450 } 451 452 static inline bool btf_is_any_enum(const struct btf_type *t) 453 { 454 return btf_is_enum(t) || btf_is_enum64(t); 455 } 456 457 static inline bool btf_kind_core_compat(const struct btf_type *t1, 458 const struct btf_type *t2) 459 { 460 return btf_kind(t1) == btf_kind(t2) || 461 (btf_is_any_enum(t1) && btf_is_any_enum(t2)); 462 } 463 464 static inline __u8 btf_int_encoding(const struct btf_type *t) 465 { 466 return BTF_INT_ENCODING(*(__u32 *)(t + 1)); 467 } 468 469 static inline __u8 btf_int_offset(const struct btf_type *t) 470 { 471 return BTF_INT_OFFSET(*(__u32 *)(t + 1)); 472 } 473 474 static inline __u8 btf_int_bits(const struct btf_type *t) 475 { 476 return BTF_INT_BITS(*(__u32 *)(t + 1)); 477 } 478 479 static inline struct btf_array *btf_array(const struct btf_type *t) 480 { 481 return (struct btf_array *)(t + 1); 482 } 483 484 static inline struct btf_enum *btf_enum(const struct btf_type *t) 485 { 486 return (struct btf_enum *)(t + 1); 487 } 488 489 struct btf_enum64; 490 491 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) 492 { 493 return (struct btf_enum64 *)(t + 1); 494 } 495 496 static inline __u64 btf_enum64_value(const struct btf_enum64 *e) 497 { 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. 502 * 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. 508 * 509 * For reference, here is a struct btf_enum64 definition: 510 * 511 * const struct btf_enum64 { 512 * __u32 name_off; 513 * __u32 val_lo32; 514 * __u32 val_hi32; 515 * }; 516 */ 517 const __u32 *e64 = (const __u32 *)e; 518 519 return ((__u64)e64[2] << 32) | e64[1]; 520 } 521 522 static inline struct btf_member *btf_members(const struct btf_type *t) 523 { 524 return (struct btf_member *)(t + 1); 525 } 526 527 /* Get bit offset of a member with specified index. */ 528 static inline __u32 btf_member_bit_offset(const struct btf_type *t, 529 __u32 member_idx) 530 { 531 const struct btf_member *m = btf_members(t) + member_idx; 532 bool kflag = btf_kflag(t); 533 534 return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset; 535 } 536 /* 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. 539 */ 540 static inline __u32 btf_member_bitfield_size(const struct btf_type *t, 541 __u32 member_idx) 542 { 543 const struct btf_member *m = btf_members(t) + member_idx; 544 bool kflag = btf_kflag(t); 545 546 return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0; 547 } 548 549 static inline struct btf_param *btf_params(const struct btf_type *t) 550 { 551 return (struct btf_param *)(t + 1); 552 } 553 554 static inline struct btf_var *btf_var(const struct btf_type *t) 555 { 556 return (struct btf_var *)(t + 1); 557 } 558 559 static inline struct btf_var_secinfo * 560 btf_var_secinfos(const struct btf_type *t) 561 { 562 return (struct btf_var_secinfo *)(t + 1); 563 } 564 565 struct btf_decl_tag; 566 static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t) 567 { 568 return (struct btf_decl_tag *)(t + 1); 569 } 570 571 #ifdef __cplusplus 572 } /* extern "C" */ 573 #endif 574 575 #endif /* __LIBBPF_BTF_H */ 576