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