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 "libbpf_legacy.h" 19 #include "relo_core.h" 20 21 /* make sure libbpf doesn't use kernel-only integer typedefs */ 22 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 23 24 /* prevent accidental re-addition of reallocarray() */ 25 #pragma GCC poison reallocarray 26 27 #include "libbpf.h" 28 #include "btf.h" 29 30 #ifndef EM_BPF 31 #define EM_BPF 247 32 #endif 33 34 #ifndef R_BPF_64_64 35 #define R_BPF_64_64 1 36 #endif 37 #ifndef R_BPF_64_ABS64 38 #define R_BPF_64_ABS64 2 39 #endif 40 #ifndef R_BPF_64_ABS32 41 #define R_BPF_64_ABS32 3 42 #endif 43 #ifndef R_BPF_64_32 44 #define R_BPF_64_32 10 45 #endif 46 47 #ifndef SHT_LLVM_ADDRSIG 48 #define SHT_LLVM_ADDRSIG 0x6FFF4C03 49 #endif 50 51 /* if libelf is old and doesn't support mmap(), fall back to read() */ 52 #ifndef ELF_C_READ_MMAP 53 #define ELF_C_READ_MMAP ELF_C_READ 54 #endif 55 56 /* Older libelf all end up in this expression, for both 32 and 64 bit */ 57 #ifndef ELF64_ST_VISIBILITY 58 #define ELF64_ST_VISIBILITY(o) ((o) & 0x03) 59 #endif 60 61 #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 62 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 63 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 64 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 65 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 66 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 67 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 68 BTF_INT_ENC(encoding, bits_offset, bits) 69 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 70 #define BTF_PARAM_ENC(name, type) (name), (type) 71 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 72 #define BTF_TYPE_FLOAT_ENC(name, sz) \ 73 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) 74 #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \ 75 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx) 76 #define BTF_TYPE_TYPE_TAG_ENC(value, type) \ 77 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type) 78 79 #ifndef likely 80 #define likely(x) __builtin_expect(!!(x), 1) 81 #endif 82 #ifndef unlikely 83 #define unlikely(x) __builtin_expect(!!(x), 0) 84 #endif 85 #ifndef min 86 # define min(x, y) ((x) < (y) ? (x) : (y)) 87 #endif 88 #ifndef max 89 # define max(x, y) ((x) < (y) ? (y) : (x)) 90 #endif 91 #ifndef offsetofend 92 # define offsetofend(TYPE, FIELD) \ 93 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 94 #endif 95 #ifndef __alias 96 #define __alias(symbol) __attribute__((alias(#symbol))) 97 #endif 98 99 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is 100 * a string literal known at compilation time or char * pointer known only at 101 * runtime. 102 */ 103 #define str_has_pfx(str, pfx) \ 104 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0) 105 106 /* Symbol versioning is different between static and shared library. 107 * Properly versioned symbols are needed for shared library, but 108 * only the symbol of the new version is needed for static library. 109 * Starting with GNU C 10, use symver attribute instead of .symver assembler 110 * directive, which works better with GCC LTO builds. 111 */ 112 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10 113 114 #define DEFAULT_VERSION(internal_name, api_name, version) \ 115 __attribute__((symver(#api_name "@@" #version))) 116 #define COMPAT_VERSION(internal_name, api_name, version) \ 117 __attribute__((symver(#api_name "@" #version))) 118 119 #elif defined(SHARED) 120 121 #define COMPAT_VERSION(internal_name, api_name, version) \ 122 asm(".symver " #internal_name "," #api_name "@" #version); 123 #define DEFAULT_VERSION(internal_name, api_name, version) \ 124 asm(".symver " #internal_name "," #api_name "@@" #version); 125 126 #else /* !SHARED */ 127 128 #define COMPAT_VERSION(internal_name, api_name, version) 129 #define DEFAULT_VERSION(internal_name, api_name, version) \ 130 extern typeof(internal_name) api_name \ 131 __attribute__((alias(#internal_name))); 132 133 #endif 134 135 extern void libbpf_print(enum libbpf_print_level level, 136 const char *format, ...) 137 __attribute__((format(printf, 2, 3))); 138 139 #define __pr(level, fmt, ...) \ 140 do { \ 141 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 142 } while (0) 143 144 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 145 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 146 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 147 148 #ifndef __has_builtin 149 #define __has_builtin(x) 0 150 #endif 151 /* 152 * Re-implement glibc's reallocarray() for libbpf internal-only use. 153 * reallocarray(), unfortunately, is not available in all versions of glibc, 154 * so requires extra feature detection and using reallocarray() stub from 155 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates 156 * build of libbpf unnecessarily and is just a maintenance burden. Instead, 157 * it's trivial to implement libbpf-specific internal version and use it 158 * throughout libbpf. 159 */ 160 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) 161 { 162 size_t total; 163 164 #if __has_builtin(__builtin_mul_overflow) 165 if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) 166 return NULL; 167 #else 168 if (size == 0 || nmemb > ULONG_MAX / size) 169 return NULL; 170 total = nmemb * size; 171 #endif 172 return realloc(ptr, total); 173 } 174 175 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst 176 * is zero-terminated string no matter what (unless sz == 0, in which case 177 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs 178 * in what is returned. Given this is internal helper, it's trivial to extend 179 * this, when necessary. Use this instead of strncpy inside libbpf source code. 180 */ 181 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz) 182 { 183 size_t i; 184 185 if (sz == 0) 186 return; 187 188 sz--; 189 for (i = 0; i < sz && src[i]; i++) 190 dst[i] = src[i]; 191 dst[i] = '\0'; 192 } 193 194 __u32 get_kernel_version(void); 195 196 struct btf; 197 struct btf_type; 198 199 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id); 200 const char *btf_kind_str(const struct btf_type *t); 201 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); 202 203 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) 204 { 205 return (enum btf_func_linkage)(int)btf_vlen(t); 206 } 207 208 static inline __u32 btf_type_info(int kind, int vlen, int kflag) 209 { 210 return (kflag << 31) | (kind << 24) | vlen; 211 } 212 213 enum map_def_parts { 214 MAP_DEF_MAP_TYPE = 0x001, 215 MAP_DEF_KEY_TYPE = 0x002, 216 MAP_DEF_KEY_SIZE = 0x004, 217 MAP_DEF_VALUE_TYPE = 0x008, 218 MAP_DEF_VALUE_SIZE = 0x010, 219 MAP_DEF_MAX_ENTRIES = 0x020, 220 MAP_DEF_MAP_FLAGS = 0x040, 221 MAP_DEF_NUMA_NODE = 0x080, 222 MAP_DEF_PINNING = 0x100, 223 MAP_DEF_INNER_MAP = 0x200, 224 MAP_DEF_MAP_EXTRA = 0x400, 225 226 MAP_DEF_ALL = 0x7ff, /* combination of all above */ 227 }; 228 229 struct btf_map_def { 230 enum map_def_parts parts; 231 __u32 map_type; 232 __u32 key_type_id; 233 __u32 key_size; 234 __u32 value_type_id; 235 __u32 value_size; 236 __u32 max_entries; 237 __u32 map_flags; 238 __u32 numa_node; 239 __u32 pinning; 240 __u64 map_extra; 241 }; 242 243 int parse_btf_map_def(const char *map_name, struct btf *btf, 244 const struct btf_type *def_t, bool strict, 245 struct btf_map_def *map_def, struct btf_map_def *inner_def); 246 247 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, 248 size_t cur_cnt, size_t max_cnt, size_t add_cnt); 249 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); 250 251 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) 252 { 253 while (len > 0) { 254 if (*p) 255 return false; 256 p++; 257 len--; 258 } 259 return true; 260 } 261 262 static inline bool libbpf_validate_opts(const char *opts, 263 size_t opts_sz, size_t user_sz, 264 const char *type_name) 265 { 266 if (user_sz < sizeof(size_t)) { 267 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 268 return false; 269 } 270 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { 271 pr_warn("%s has non-zero extra bytes\n", type_name); 272 return false; 273 } 274 return true; 275 } 276 277 #define OPTS_VALID(opts, type) \ 278 (!(opts) || libbpf_validate_opts((const char *)opts, \ 279 offsetofend(struct type, \ 280 type##__last_field), \ 281 (opts)->sz, #type)) 282 #define OPTS_HAS(opts, field) \ 283 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 284 #define OPTS_GET(opts, field, fallback_value) \ 285 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 286 #define OPTS_SET(opts, field, value) \ 287 do { \ 288 if (OPTS_HAS(opts, field)) \ 289 (opts)->field = value; \ 290 } while (0) 291 292 #define OPTS_ZEROED(opts, last_nonzero_field) \ 293 ({ \ 294 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ 295 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ 296 (opts)->sz - __off); \ 297 }) 298 299 enum kern_feature_id { 300 /* v4.14: kernel support for program & map names. */ 301 FEAT_PROG_NAME, 302 /* v5.2: kernel support for global data sections. */ 303 FEAT_GLOBAL_DATA, 304 /* BTF support */ 305 FEAT_BTF, 306 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */ 307 FEAT_BTF_FUNC, 308 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ 309 FEAT_BTF_DATASEC, 310 /* BTF_FUNC_GLOBAL is supported */ 311 FEAT_BTF_GLOBAL_FUNC, 312 /* BPF_F_MMAPABLE is supported for arrays */ 313 FEAT_ARRAY_MMAP, 314 /* kernel support for expected_attach_type in BPF_PROG_LOAD */ 315 FEAT_EXP_ATTACH_TYPE, 316 /* bpf_probe_read_{kernel,user}[_str] helpers */ 317 FEAT_PROBE_READ_KERN, 318 /* BPF_PROG_BIND_MAP is supported */ 319 FEAT_PROG_BIND_MAP, 320 /* Kernel support for module BTFs */ 321 FEAT_MODULE_BTF, 322 /* BTF_KIND_FLOAT support */ 323 FEAT_BTF_FLOAT, 324 /* BPF perf link support */ 325 FEAT_PERF_LINK, 326 /* BTF_KIND_DECL_TAG support */ 327 FEAT_BTF_DECL_TAG, 328 /* BTF_KIND_TYPE_TAG support */ 329 FEAT_BTF_TYPE_TAG, 330 /* memcg-based accounting for BPF maps and progs */ 331 FEAT_MEMCG_ACCOUNT, 332 __FEAT_CNT, 333 }; 334 335 int probe_memcg_account(void); 336 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); 337 int bump_rlimit_memlock(void); 338 339 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 340 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 341 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 342 const char *str_sec, size_t str_len); 343 int btf_load_into_kernel(struct btf *btf, char *log_buf, size_t log_sz, __u32 log_level); 344 345 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); 346 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, 347 const char **prefix, int *kind); 348 349 struct btf_ext_info { 350 /* 351 * info points to the individual info section (e.g. func_info and 352 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 353 */ 354 void *info; 355 __u32 rec_size; 356 __u32 len; 357 }; 358 359 #define for_each_btf_ext_sec(seg, sec) \ 360 for (sec = (seg)->info; \ 361 (void *)sec < (seg)->info + (seg)->len; \ 362 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 363 (seg)->rec_size * sec->num_info) 364 365 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 366 for (i = 0, rec = (void *)&(sec)->data; \ 367 i < (sec)->num_info; \ 368 i++, rec = (void *)rec + (seg)->rec_size) 369 370 /* 371 * The .BTF.ext ELF section layout defined as 372 * struct btf_ext_header 373 * func_info subsection 374 * 375 * The func_info subsection layout: 376 * record size for struct bpf_func_info in the func_info subsection 377 * struct btf_sec_func_info for section #1 378 * a list of bpf_func_info records for section #1 379 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h 380 * but may not be identical 381 * struct btf_sec_func_info for section #2 382 * a list of bpf_func_info records for section #2 383 * ...... 384 * 385 * Note that the bpf_func_info record size in .BTF.ext may not 386 * be the same as the one defined in include/uapi/linux/bpf.h. 387 * The loader should ensure that record_size meets minimum 388 * requirement and pass the record as is to the kernel. The 389 * kernel will handle the func_info properly based on its contents. 390 */ 391 struct btf_ext_header { 392 __u16 magic; 393 __u8 version; 394 __u8 flags; 395 __u32 hdr_len; 396 397 /* All offsets are in bytes relative to the end of this header */ 398 __u32 func_info_off; 399 __u32 func_info_len; 400 __u32 line_info_off; 401 __u32 line_info_len; 402 403 /* optional part of .BTF.ext header */ 404 __u32 core_relo_off; 405 __u32 core_relo_len; 406 }; 407 408 struct btf_ext { 409 union { 410 struct btf_ext_header *hdr; 411 void *data; 412 }; 413 struct btf_ext_info func_info; 414 struct btf_ext_info line_info; 415 struct btf_ext_info core_relo_info; 416 __u32 data_size; 417 }; 418 419 struct btf_ext_info_sec { 420 __u32 sec_name_off; 421 __u32 num_info; 422 /* Followed by num_info * record_size number of bytes */ 423 __u8 data[]; 424 }; 425 426 /* The minimum bpf_func_info checked by the loader */ 427 struct bpf_func_info_min { 428 __u32 insn_off; 429 __u32 type_id; 430 }; 431 432 /* The minimum bpf_line_info checked by the loader */ 433 struct bpf_line_info_min { 434 __u32 insn_off; 435 __u32 file_name_off; 436 __u32 line_off; 437 __u32 line_col; 438 }; 439 440 441 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); 442 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); 443 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); 444 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); 445 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); 446 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); 447 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, 448 __u32 kind); 449 450 extern enum libbpf_strict_mode libbpf_mode; 451 452 typedef int (*kallsyms_cb_t)(unsigned long long sym_addr, char sym_type, 453 const char *sym_name, void *ctx); 454 455 int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *arg); 456 457 /* handle direct returned errors */ 458 static inline int libbpf_err(int ret) 459 { 460 if (ret < 0) 461 errno = -ret; 462 return ret; 463 } 464 465 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's 466 * strict mode settings 467 */ 468 static inline int libbpf_err_errno(int ret) 469 { 470 if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS) 471 /* errno is already assumed to be set on error */ 472 return ret < 0 ? -errno : ret; 473 474 /* legacy: on error return -1 directly and don't touch errno */ 475 return ret; 476 } 477 478 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */ 479 static inline void *libbpf_err_ptr(int err) 480 { 481 /* set errno on error, this doesn't break anything */ 482 errno = -err; 483 484 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) 485 return NULL; 486 487 /* legacy: encode err as ptr */ 488 return ERR_PTR(err); 489 } 490 491 /* handle pointer-returning APIs' error handling */ 492 static inline void *libbpf_ptr(void *ret) 493 { 494 /* set errno on error, this doesn't break anything */ 495 if (IS_ERR(ret)) 496 errno = -PTR_ERR(ret); 497 498 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) 499 return IS_ERR(ret) ? NULL : ret; 500 501 /* legacy: pass-through original pointer */ 502 return ret; 503 } 504 505 static inline bool str_is_empty(const char *s) 506 { 507 return !s || !s[0]; 508 } 509 510 static inline bool is_ldimm64_insn(struct bpf_insn *insn) 511 { 512 return insn->code == (BPF_LD | BPF_IMM | BPF_DW); 513 } 514 515 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2 516 * Takes ownership of the fd passed in, and closes it if calling 517 * fcntl(fd, F_DUPFD_CLOEXEC, 3). 518 */ 519 static inline int ensure_good_fd(int fd) 520 { 521 int old_fd = fd, saved_errno; 522 523 if (fd < 0) 524 return fd; 525 if (fd < 3) { 526 fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); 527 saved_errno = errno; 528 close(old_fd); 529 if (fd < 0) { 530 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); 531 errno = saved_errno; 532 } 533 } 534 return fd; 535 } 536 537 /* The following two functions are exposed to bpftool */ 538 int bpf_core_add_cands(struct bpf_core_cand *local_cand, 539 size_t local_essent_len, 540 const struct btf *targ_btf, 541 const char *targ_btf_name, 542 int targ_start_id, 543 struct bpf_core_cand_list *cands); 544 void bpf_core_free_cands(struct bpf_core_cand_list *cands); 545 546 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 547