1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 3 /* 4 * Internal libbpf helpers. 5 * 6 * Copyright (c) 2019 Facebook 7 */ 8 9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H 10 #define __LIBBPF_LIBBPF_INTERNAL_H 11 12 #include <stdlib.h> 13 #include <byteswap.h> 14 #include <limits.h> 15 #include <errno.h> 16 #include <linux/err.h> 17 #include <fcntl.h> 18 #include <unistd.h> 19 #include <sys/syscall.h> 20 #include <libelf.h> 21 #include "relo_core.h" 22 23 /* Android's libc doesn't support AT_EACCESS in faccessat() implementation 24 * ([0]), and just returns -EINVAL even if file exists and is accessible. 25 * See [1] for issues caused by this. 26 * 27 * So just redefine it to 0 on Android. 28 * 29 * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50 30 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250 31 */ 32 #ifdef __ANDROID__ 33 #undef AT_EACCESS 34 #define AT_EACCESS 0 35 #endif 36 37 /* make sure libbpf doesn't use kernel-only integer typedefs */ 38 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 39 40 /* prevent accidental re-addition of reallocarray() */ 41 #pragma GCC poison reallocarray 42 43 #include "libbpf.h" 44 #include "btf.h" 45 46 #ifndef EM_BPF 47 #define EM_BPF 247 48 #endif 49 50 #ifndef R_BPF_64_64 51 #define R_BPF_64_64 1 52 #endif 53 #ifndef R_BPF_64_ABS64 54 #define R_BPF_64_ABS64 2 55 #endif 56 #ifndef R_BPF_64_ABS32 57 #define R_BPF_64_ABS32 3 58 #endif 59 #ifndef R_BPF_64_32 60 #define R_BPF_64_32 10 61 #endif 62 63 #ifndef SHT_LLVM_ADDRSIG 64 #define SHT_LLVM_ADDRSIG 0x6FFF4C03 65 #endif 66 67 /* if libelf is old and doesn't support mmap(), fall back to read() */ 68 #ifndef ELF_C_READ_MMAP 69 #define ELF_C_READ_MMAP ELF_C_READ 70 #endif 71 72 /* Older libelf all end up in this expression, for both 32 and 64 bit */ 73 #ifndef ELF64_ST_VISIBILITY 74 #define ELF64_ST_VISIBILITY(o) ((o) & 0x03) 75 #endif 76 77 #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 78 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 79 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 80 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 81 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 82 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 83 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 84 BTF_INT_ENC(encoding, bits_offset, bits) 85 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 86 #define BTF_PARAM_ENC(name, type) (name), (type) 87 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 88 #define BTF_TYPE_FLOAT_ENC(name, sz) \ 89 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) 90 #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \ 91 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx) 92 #define BTF_TYPE_TYPE_TAG_ENC(value, type) \ 93 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type) 94 95 #ifndef likely 96 #define likely(x) __builtin_expect(!!(x), 1) 97 #endif 98 #ifndef unlikely 99 #define unlikely(x) __builtin_expect(!!(x), 0) 100 #endif 101 #ifndef min 102 # define min(x, y) ((x) < (y) ? (x) : (y)) 103 #endif 104 #ifndef max 105 # define max(x, y) ((x) < (y) ? (y) : (x)) 106 #endif 107 #ifndef offsetofend 108 # define offsetofend(TYPE, FIELD) \ 109 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 110 #endif 111 #ifndef __alias 112 #define __alias(symbol) __attribute__((alias(#symbol))) 113 #endif 114 115 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is 116 * a string literal known at compilation time or char * pointer known only at 117 * runtime. 118 */ 119 #define str_has_pfx(str, pfx) \ 120 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0) 121 122 /* suffix check */ 123 static inline bool str_has_sfx(const char *str, const char *sfx) 124 { 125 size_t str_len = strlen(str); 126 size_t sfx_len = strlen(sfx); 127 128 if (sfx_len > str_len) 129 return false; 130 return strcmp(str + str_len - sfx_len, sfx) == 0; 131 } 132 133 /* Symbol versioning is different between static and shared library. 134 * Properly versioned symbols are needed for shared library, but 135 * only the symbol of the new version is needed for static library. 136 * Starting with GNU C 10, use symver attribute instead of .symver assembler 137 * directive, which works better with GCC LTO builds. 138 */ 139 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10 140 141 #define DEFAULT_VERSION(internal_name, api_name, version) \ 142 __attribute__((symver(#api_name "@@" #version))) 143 #define COMPAT_VERSION(internal_name, api_name, version) \ 144 __attribute__((symver(#api_name "@" #version))) 145 146 #elif defined(SHARED) 147 148 #define COMPAT_VERSION(internal_name, api_name, version) \ 149 asm(".symver " #internal_name "," #api_name "@" #version); 150 #define DEFAULT_VERSION(internal_name, api_name, version) \ 151 asm(".symver " #internal_name "," #api_name "@@" #version); 152 153 #else /* !SHARED */ 154 155 #define COMPAT_VERSION(internal_name, api_name, version) 156 #define DEFAULT_VERSION(internal_name, api_name, version) \ 157 extern typeof(internal_name) api_name \ 158 __attribute__((alias(#internal_name))); 159 160 #endif 161 162 extern void libbpf_print(enum libbpf_print_level level, 163 const char *format, ...) 164 __attribute__((format(printf, 2, 3))); 165 166 #define __pr(level, fmt, ...) \ 167 do { \ 168 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 169 } while (0) 170 171 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 172 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 173 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 174 175 #ifndef __has_builtin 176 #define __has_builtin(x) 0 177 #endif 178 179 struct bpf_link { 180 int (*detach)(struct bpf_link *link); 181 void (*dealloc)(struct bpf_link *link); 182 char *pin_path; /* NULL, if not pinned */ 183 int fd; /* hook FD, -1 if not applicable */ 184 bool disconnected; 185 }; 186 187 /* 188 * Re-implement glibc's reallocarray() for libbpf internal-only use. 189 * reallocarray(), unfortunately, is not available in all versions of glibc, 190 * so requires extra feature detection and using reallocarray() stub from 191 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates 192 * build of libbpf unnecessarily and is just a maintenance burden. Instead, 193 * it's trivial to implement libbpf-specific internal version and use it 194 * throughout libbpf. 195 */ 196 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) 197 { 198 size_t total; 199 200 #if __has_builtin(__builtin_mul_overflow) 201 if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) 202 return NULL; 203 #else 204 if (size == 0 || nmemb > ULONG_MAX / size) 205 return NULL; 206 total = nmemb * size; 207 #endif 208 return realloc(ptr, total); 209 } 210 211 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst 212 * is zero-terminated string no matter what (unless sz == 0, in which case 213 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs 214 * in what is returned. Given this is internal helper, it's trivial to extend 215 * this, when necessary. Use this instead of strncpy inside libbpf source code. 216 */ 217 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz) 218 { 219 size_t i; 220 221 if (sz == 0) 222 return; 223 224 sz--; 225 for (i = 0; i < sz && src[i]; i++) 226 dst[i] = src[i]; 227 dst[i] = '\0'; 228 } 229 230 __u32 get_kernel_version(void); 231 232 struct btf; 233 struct btf_type; 234 235 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); 236 const char *btf_kind_str(const struct btf_type *t); 237 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); 238 const struct btf_header *btf_header(const struct btf *btf); 239 void btf_set_base_btf(struct btf *btf, const struct btf *base_btf); 240 int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map); 241 242 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) 243 { 244 return (enum btf_func_linkage)(int)btf_vlen(t); 245 } 246 247 static inline __u32 btf_type_info(int kind, int vlen, int kflag) 248 { 249 return (kflag << 31) | (kind << 24) | vlen; 250 } 251 252 enum map_def_parts { 253 MAP_DEF_MAP_TYPE = 0x001, 254 MAP_DEF_KEY_TYPE = 0x002, 255 MAP_DEF_KEY_SIZE = 0x004, 256 MAP_DEF_VALUE_TYPE = 0x008, 257 MAP_DEF_VALUE_SIZE = 0x010, 258 MAP_DEF_MAX_ENTRIES = 0x020, 259 MAP_DEF_MAP_FLAGS = 0x040, 260 MAP_DEF_NUMA_NODE = 0x080, 261 MAP_DEF_PINNING = 0x100, 262 MAP_DEF_INNER_MAP = 0x200, 263 MAP_DEF_MAP_EXTRA = 0x400, 264 265 MAP_DEF_ALL = 0x7ff, /* combination of all above */ 266 }; 267 268 struct btf_map_def { 269 enum map_def_parts parts; 270 __u32 map_type; 271 __u32 key_type_id; 272 __u32 key_size; 273 __u32 value_type_id; 274 __u32 value_size; 275 __u32 max_entries; 276 __u32 map_flags; 277 __u32 numa_node; 278 __u32 pinning; 279 __u64 map_extra; 280 }; 281 282 int parse_btf_map_def(const char *map_name, struct btf *btf, 283 const struct btf_type *def_t, bool strict, 284 struct btf_map_def *map_def, struct btf_map_def *inner_def); 285 286 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, 287 size_t cur_cnt, size_t max_cnt, size_t add_cnt); 288 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); 289 290 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) 291 { 292 while (len > 0) { 293 if (*p) 294 return false; 295 p++; 296 len--; 297 } 298 return true; 299 } 300 301 static inline bool libbpf_validate_opts(const char *opts, 302 size_t opts_sz, size_t user_sz, 303 const char *type_name) 304 { 305 if (user_sz < sizeof(size_t)) { 306 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 307 return false; 308 } 309 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { 310 pr_warn("%s has non-zero extra bytes\n", type_name); 311 return false; 312 } 313 return true; 314 } 315 316 #define OPTS_VALID(opts, type) \ 317 (!(opts) || libbpf_validate_opts((const char *)opts, \ 318 offsetofend(struct type, \ 319 type##__last_field), \ 320 (opts)->sz, #type)) 321 #define OPTS_HAS(opts, field) \ 322 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 323 #define OPTS_GET(opts, field, fallback_value) \ 324 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 325 #define OPTS_SET(opts, field, value) \ 326 do { \ 327 if (OPTS_HAS(opts, field)) \ 328 (opts)->field = value; \ 329 } while (0) 330 331 #define OPTS_ZEROED(opts, last_nonzero_field) \ 332 ({ \ 333 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ 334 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ 335 (opts)->sz - __off); \ 336 }) 337 338 enum kern_feature_id { 339 /* v4.14: kernel support for program & map names. */ 340 FEAT_PROG_NAME, 341 /* v5.2: kernel support for global data sections. */ 342 FEAT_GLOBAL_DATA, 343 /* BTF support */ 344 FEAT_BTF, 345 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ 346 FEAT_BTF_FUNC, 347 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ 348 FEAT_BTF_DATASEC, 349 /* BTF_FUNC_GLOBAL is supported */ 350 FEAT_BTF_GLOBAL_FUNC, 351 /* BPF_F_MMAPABLE is supported for arrays */ 352 FEAT_ARRAY_MMAP, 353 /* kernel support for expected_attach_type in BPF_PROG_LOAD */ 354 FEAT_EXP_ATTACH_TYPE, 355 /* bpf_probe_read_{kernel,user}[_str] helpers */ 356 FEAT_PROBE_READ_KERN, 357 /* BPF_PROG_BIND_MAP is supported */ 358 FEAT_PROG_BIND_MAP, 359 /* Kernel support for module BTFs */ 360 FEAT_MODULE_BTF, 361 /* BTF_KIND_FLOAT support */ 362 FEAT_BTF_FLOAT, 363 /* BPF perf link support */ 364 FEAT_PERF_LINK, 365 /* BTF_KIND_DECL_TAG support */ 366 FEAT_BTF_DECL_TAG, 367 /* BTF_KIND_TYPE_TAG support */ 368 FEAT_BTF_TYPE_TAG, 369 /* memcg-based accounting for BPF maps and progs */ 370 FEAT_MEMCG_ACCOUNT, 371 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */ 372 FEAT_BPF_COOKIE, 373 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */ 374 FEAT_BTF_ENUM64, 375 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */ 376 FEAT_SYSCALL_WRAPPER, 377 /* BPF multi-uprobe link support */ 378 FEAT_UPROBE_MULTI_LINK, 379 /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */ 380 FEAT_ARG_CTX_TAG, 381 /* Kernel supports '?' at the front of datasec names */ 382 FEAT_BTF_QMARK_DATASEC, 383 __FEAT_CNT, 384 }; 385 386 enum kern_feature_result { 387 FEAT_UNKNOWN = 0, 388 FEAT_SUPPORTED = 1, 389 FEAT_MISSING = 2, 390 }; 391 392 struct kern_feature_cache { 393 enum kern_feature_result res[__FEAT_CNT]; 394 int token_fd; 395 }; 396 397 bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id); 398 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); 399 400 int probe_kern_syscall_wrapper(int token_fd); 401 int probe_memcg_account(int token_fd); 402 int bump_rlimit_memlock(void); 403 404 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 405 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 406 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 407 const char *str_sec, size_t str_len, 408 int token_fd); 409 int btf_load_into_kernel(struct btf *btf, 410 char *log_buf, size_t log_sz, __u32 log_level, 411 int token_fd); 412 struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd); 413 414 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); 415 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, 416 const char **prefix, int *kind); 417 418 struct btf_ext_info { 419 /* 420 * info points to the individual info section (e.g. func_info and 421 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 422 */ 423 void *info; 424 __u32 rec_size; 425 __u32 len; 426 /* optional (maintained internally by libbpf) mapping between .BTF.ext 427 * section and corresponding ELF section. This is used to join 428 * information like CO-RE relocation records with corresponding BPF 429 * programs defined in ELF sections 430 */ 431 __u32 *sec_idxs; 432 int sec_cnt; 433 }; 434 435 #define for_each_btf_ext_sec(seg, sec) \ 436 for (sec = (seg)->info; \ 437 (void *)sec < (seg)->info + (seg)->len; \ 438 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 439 (seg)->rec_size * sec->num_info) 440 441 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 442 for (i = 0, rec = (void *)&(sec)->data; \ 443 i < (sec)->num_info; \ 444 i++, rec = (void *)rec + (seg)->rec_size) 445 446 /* 447 * The .BTF.ext ELF section layout defined as 448 * struct btf_ext_header 449 * func_info subsection 450 * 451 * The func_info subsection layout: 452 * record size for struct bpf_func_info in the func_info subsection 453 * struct btf_ext_info_sec for section #1 454 * a list of bpf_func_info records for section #1 455 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h 456 * but may not be identical 457 * struct btf_ext_info_sec for section #2 458 * a list of bpf_func_info records for section #2 459 * ...... 460 * 461 * Note that the bpf_func_info record size in .BTF.ext may not 462 * be the same as the one defined in include/uapi/linux/bpf.h. 463 * The loader should ensure that record_size meets minimum 464 * requirement and pass the record as is to the kernel. The 465 * kernel will handle the func_info properly based on its contents. 466 */ 467 struct btf_ext_header { 468 __u16 magic; 469 __u8 version; 470 __u8 flags; 471 __u32 hdr_len; 472 473 /* All offsets are in bytes relative to the end of this header */ 474 __u32 func_info_off; 475 __u32 func_info_len; 476 __u32 line_info_off; 477 __u32 line_info_len; 478 479 /* optional part of .BTF.ext header */ 480 __u32 core_relo_off; 481 __u32 core_relo_len; 482 }; 483 484 struct btf_ext { 485 union { 486 struct btf_ext_header *hdr; 487 void *data; 488 }; 489 void *data_swapped; 490 bool swapped_endian; 491 struct btf_ext_info func_info; 492 struct btf_ext_info line_info; 493 struct btf_ext_info core_relo_info; 494 __u32 data_size; 495 }; 496 497 struct btf_ext_info_sec { 498 __u32 sec_name_off; 499 __u32 num_info; 500 /* Followed by num_info * record_size number of bytes */ 501 __u8 data[]; 502 }; 503 504 /* The minimum bpf_func_info checked by the loader */ 505 struct bpf_func_info_min { 506 __u32 insn_off; 507 __u32 type_id; 508 }; 509 510 /* The minimum bpf_line_info checked by the loader */ 511 struct bpf_line_info_min { 512 __u32 insn_off; 513 __u32 file_name_off; 514 __u32 line_off; 515 __u32 line_col; 516 }; 517 518 /* Functions to byte-swap info records */ 519 520 typedef void (*info_rec_bswap_fn)(void *); 521 522 static inline void bpf_func_info_bswap(struct bpf_func_info *i) 523 { 524 i->insn_off = bswap_32(i->insn_off); 525 i->type_id = bswap_32(i->type_id); 526 } 527 528 static inline void bpf_line_info_bswap(struct bpf_line_info *i) 529 { 530 i->insn_off = bswap_32(i->insn_off); 531 i->file_name_off = bswap_32(i->file_name_off); 532 i->line_off = bswap_32(i->line_off); 533 i->line_col = bswap_32(i->line_col); 534 } 535 536 static inline void bpf_core_relo_bswap(struct bpf_core_relo *i) 537 { 538 i->insn_off = bswap_32(i->insn_off); 539 i->type_id = bswap_32(i->type_id); 540 i->access_str_off = bswap_32(i->access_str_off); 541 i->kind = bswap_32(i->kind); 542 } 543 544 enum btf_field_iter_kind { 545 BTF_FIELD_ITER_IDS, 546 BTF_FIELD_ITER_STRS, 547 }; 548 549 struct btf_field_desc { 550 /* once-per-type offsets */ 551 int t_off_cnt, t_offs[2]; 552 /* member struct size, or zero, if no members */ 553 int m_sz; 554 /* repeated per-member offsets */ 555 int m_off_cnt, m_offs[1]; 556 }; 557 558 struct btf_field_iter { 559 struct btf_field_desc desc; 560 void *p; 561 int m_idx; 562 int off_idx; 563 int vlen; 564 }; 565 566 int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind); 567 __u32 *btf_field_iter_next(struct btf_field_iter *it); 568 569 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); 570 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); 571 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); 572 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); 573 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, 574 __u32 kind); 575 576 /* handle direct returned errors */ 577 static inline int libbpf_err(int ret) 578 { 579 if (ret < 0) 580 errno = -ret; 581 return ret; 582 } 583 584 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's 585 * strict mode settings 586 */ 587 static inline int libbpf_err_errno(int ret) 588 { 589 /* errno is already assumed to be set on error */ 590 return ret < 0 ? -errno : ret; 591 } 592 593 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */ 594 static inline void *libbpf_err_ptr(int err) 595 { 596 /* set errno on error, this doesn't break anything */ 597 errno = -err; 598 return NULL; 599 } 600 601 /* handle pointer-returning APIs' error handling */ 602 static inline void *libbpf_ptr(void *ret) 603 { 604 /* set errno on error, this doesn't break anything */ 605 if (IS_ERR(ret)) 606 errno = -PTR_ERR(ret); 607 608 return IS_ERR(ret) ? NULL : ret; 609 } 610 611 static inline bool str_is_empty(const char *s) 612 { 613 return !s || !s[0]; 614 } 615 616 static inline bool is_ldimm64_insn(struct bpf_insn *insn) 617 { 618 return insn->code == (BPF_LD | BPF_IMM | BPF_DW); 619 } 620 621 static inline void bpf_insn_bswap(struct bpf_insn *insn) 622 { 623 __u8 tmp_reg = insn->dst_reg; 624 625 insn->dst_reg = insn->src_reg; 626 insn->src_reg = tmp_reg; 627 insn->off = bswap_16(insn->off); 628 insn->imm = bswap_32(insn->imm); 629 } 630 631 /* Unconditionally dup FD, ensuring it doesn't use [0, 2] range. 632 * Original FD is not closed or altered in any other way. 633 * Preserves original FD value, if it's invalid (negative). 634 */ 635 static inline int dup_good_fd(int fd) 636 { 637 if (fd < 0) 638 return fd; 639 return fcntl(fd, F_DUPFD_CLOEXEC, 3); 640 } 641 642 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2 643 * Takes ownership of the fd passed in, and closes it if calling 644 * fcntl(fd, F_DUPFD_CLOEXEC, 3). 645 */ 646 static inline int ensure_good_fd(int fd) 647 { 648 int old_fd = fd, saved_errno; 649 650 if (fd < 0) 651 return fd; 652 if (fd < 3) { 653 fd = dup_good_fd(fd); 654 saved_errno = errno; 655 close(old_fd); 656 errno = saved_errno; 657 if (fd < 0) { 658 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); 659 errno = saved_errno; 660 } 661 } 662 return fd; 663 } 664 665 static inline int sys_dup3(int oldfd, int newfd, int flags) 666 { 667 return syscall(__NR_dup3, oldfd, newfd, flags); 668 } 669 670 /* Point *fixed_fd* to the same file that *tmp_fd* points to. 671 * Regardless of success, *tmp_fd* is closed. 672 * Whatever *fixed_fd* pointed to is closed silently. 673 */ 674 static inline int reuse_fd(int fixed_fd, int tmp_fd) 675 { 676 int err; 677 678 err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC); 679 err = err < 0 ? -errno : 0; 680 close(tmp_fd); /* clean up temporary FD */ 681 return err; 682 } 683 684 /* The following two functions are exposed to bpftool */ 685 int bpf_core_add_cands(struct bpf_core_cand *local_cand, 686 size_t local_essent_len, 687 const struct btf *targ_btf, 688 const char *targ_btf_name, 689 int targ_start_id, 690 struct bpf_core_cand_list *cands); 691 void bpf_core_free_cands(struct bpf_core_cand_list *cands); 692 693 struct usdt_manager *usdt_manager_new(struct bpf_object *obj); 694 void usdt_manager_free(struct usdt_manager *man); 695 struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man, 696 const struct bpf_program *prog, 697 pid_t pid, const char *path, 698 const char *usdt_provider, const char *usdt_name, 699 __u64 usdt_cookie); 700 701 static inline bool is_pow_of_2(size_t x) 702 { 703 return x && (x & (x - 1)) == 0; 704 } 705 706 #define PROG_LOAD_ATTEMPTS 5 707 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts); 708 709 bool glob_match(const char *str, const char *pat); 710 711 long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name); 712 long elf_find_func_offset_from_file(const char *binary_path, const char *name); 713 714 struct elf_fd { 715 Elf *elf; 716 int fd; 717 }; 718 719 int elf_open(const char *binary_path, struct elf_fd *elf_fd); 720 void elf_close(struct elf_fd *elf_fd); 721 722 int elf_resolve_syms_offsets(const char *binary_path, int cnt, 723 const char **syms, unsigned long **poffsets, 724 int st_type); 725 int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern, 726 unsigned long **poffsets, size_t *pcnt); 727 728 int probe_fd(int fd); 729 730 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 731