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 77 #ifndef likely 78 #define likely(x) __builtin_expect(!!(x), 1) 79 #endif 80 #ifndef unlikely 81 #define unlikely(x) __builtin_expect(!!(x), 0) 82 #endif 83 #ifndef min 84 # define min(x, y) ((x) < (y) ? (x) : (y)) 85 #endif 86 #ifndef max 87 # define max(x, y) ((x) < (y) ? (y) : (x)) 88 #endif 89 #ifndef offsetofend 90 # define offsetofend(TYPE, FIELD) \ 91 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 92 #endif 93 94 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is 95 * a string literal known at compilation time or char * pointer known only at 96 * runtime. 97 */ 98 #define str_has_pfx(str, pfx) \ 99 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0) 100 101 /* Symbol versioning is different between static and shared library. 102 * Properly versioned symbols are needed for shared library, but 103 * only the symbol of the new version is needed for static library. 104 * Starting with GNU C 10, use symver attribute instead of .symver assembler 105 * directive, which works better with GCC LTO builds. 106 */ 107 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10 108 109 #define DEFAULT_VERSION(internal_name, api_name, version) \ 110 __attribute__((symver(#api_name "@@" #version))) 111 #define COMPAT_VERSION(internal_name, api_name, version) \ 112 __attribute__((symver(#api_name "@" #version))) 113 114 #elif defined(SHARED) 115 116 #define COMPAT_VERSION(internal_name, api_name, version) \ 117 asm(".symver " #internal_name "," #api_name "@" #version); 118 #define DEFAULT_VERSION(internal_name, api_name, version) \ 119 asm(".symver " #internal_name "," #api_name "@@" #version); 120 121 #else /* !SHARED */ 122 123 #define COMPAT_VERSION(internal_name, api_name, version) 124 #define DEFAULT_VERSION(internal_name, api_name, version) \ 125 extern typeof(internal_name) api_name \ 126 __attribute__((alias(#internal_name))); 127 128 #endif 129 130 extern void libbpf_print(enum libbpf_print_level level, 131 const char *format, ...) 132 __attribute__((format(printf, 2, 3))); 133 134 #define __pr(level, fmt, ...) \ 135 do { \ 136 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 137 } while (0) 138 139 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 140 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 141 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 142 143 #ifndef __has_builtin 144 #define __has_builtin(x) 0 145 #endif 146 /* 147 * Re-implement glibc's reallocarray() for libbpf internal-only use. 148 * reallocarray(), unfortunately, is not available in all versions of glibc, 149 * so requires extra feature detection and using reallocarray() stub from 150 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates 151 * build of libbpf unnecessarily and is just a maintenance burden. Instead, 152 * it's trivial to implement libbpf-specific internal version and use it 153 * throughout libbpf. 154 */ 155 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) 156 { 157 size_t total; 158 159 #if __has_builtin(__builtin_mul_overflow) 160 if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) 161 return NULL; 162 #else 163 if (size == 0 || nmemb > ULONG_MAX / size) 164 return NULL; 165 total = nmemb * size; 166 #endif 167 return realloc(ptr, total); 168 } 169 170 struct btf; 171 struct btf_type; 172 173 struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id); 174 const char *btf_kind_str(const struct btf_type *t); 175 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); 176 177 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) 178 { 179 return (enum btf_func_linkage)(int)btf_vlen(t); 180 } 181 182 static inline __u32 btf_type_info(int kind, int vlen, int kflag) 183 { 184 return (kflag << 31) | (kind << 24) | vlen; 185 } 186 187 enum map_def_parts { 188 MAP_DEF_MAP_TYPE = 0x001, 189 MAP_DEF_KEY_TYPE = 0x002, 190 MAP_DEF_KEY_SIZE = 0x004, 191 MAP_DEF_VALUE_TYPE = 0x008, 192 MAP_DEF_VALUE_SIZE = 0x010, 193 MAP_DEF_MAX_ENTRIES = 0x020, 194 MAP_DEF_MAP_FLAGS = 0x040, 195 MAP_DEF_NUMA_NODE = 0x080, 196 MAP_DEF_PINNING = 0x100, 197 MAP_DEF_INNER_MAP = 0x200, 198 MAP_DEF_MAP_EXTRA = 0x400, 199 200 MAP_DEF_ALL = 0x7ff, /* combination of all above */ 201 }; 202 203 struct btf_map_def { 204 enum map_def_parts parts; 205 __u32 map_type; 206 __u32 key_type_id; 207 __u32 key_size; 208 __u32 value_type_id; 209 __u32 value_size; 210 __u32 max_entries; 211 __u32 map_flags; 212 __u32 numa_node; 213 __u32 pinning; 214 __u64 map_extra; 215 }; 216 217 int parse_btf_map_def(const char *map_name, struct btf *btf, 218 const struct btf_type *def_t, bool strict, 219 struct btf_map_def *map_def, struct btf_map_def *inner_def); 220 221 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, 222 size_t cur_cnt, size_t max_cnt, size_t add_cnt); 223 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); 224 225 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len) 226 { 227 while (len > 0) { 228 if (*p) 229 return false; 230 p++; 231 len--; 232 } 233 return true; 234 } 235 236 static inline bool libbpf_validate_opts(const char *opts, 237 size_t opts_sz, size_t user_sz, 238 const char *type_name) 239 { 240 if (user_sz < sizeof(size_t)) { 241 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 242 return false; 243 } 244 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) { 245 pr_warn("%s has non-zero extra bytes\n", type_name); 246 return false; 247 } 248 return true; 249 } 250 251 #define OPTS_VALID(opts, type) \ 252 (!(opts) || libbpf_validate_opts((const char *)opts, \ 253 offsetofend(struct type, \ 254 type##__last_field), \ 255 (opts)->sz, #type)) 256 #define OPTS_HAS(opts, field) \ 257 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 258 #define OPTS_GET(opts, field, fallback_value) \ 259 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 260 #define OPTS_SET(opts, field, value) \ 261 do { \ 262 if (OPTS_HAS(opts, field)) \ 263 (opts)->field = value; \ 264 } while (0) 265 266 #define OPTS_ZEROED(opts, last_nonzero_field) \ 267 ({ \ 268 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \ 269 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \ 270 (opts)->sz - __off); \ 271 }) 272 273 274 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 275 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 276 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 277 const char *str_sec, size_t str_len); 278 279 struct bpf_prog_load_params { 280 enum bpf_prog_type prog_type; 281 enum bpf_attach_type expected_attach_type; 282 const char *name; 283 const struct bpf_insn *insns; 284 size_t insn_cnt; 285 const char *license; 286 __u32 kern_version; 287 __u32 attach_prog_fd; 288 __u32 attach_btf_obj_fd; 289 __u32 attach_btf_id; 290 __u32 prog_ifindex; 291 __u32 prog_btf_fd; 292 __u32 prog_flags; 293 294 __u32 func_info_rec_size; 295 const void *func_info; 296 __u32 func_info_cnt; 297 298 __u32 line_info_rec_size; 299 const void *line_info; 300 __u32 line_info_cnt; 301 302 __u32 log_level; 303 char *log_buf; 304 size_t log_buf_sz; 305 int *fd_array; 306 }; 307 308 int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr); 309 310 struct bpf_create_map_params { 311 const char *name; 312 enum bpf_map_type map_type; 313 __u32 map_flags; 314 __u32 key_size; 315 __u32 value_size; 316 __u32 max_entries; 317 __u32 numa_node; 318 __u32 btf_fd; 319 __u32 btf_key_type_id; 320 __u32 btf_value_type_id; 321 __u32 map_ifindex; 322 union { 323 __u32 inner_map_fd; 324 __u32 btf_vmlinux_value_type_id; 325 }; 326 __u64 map_extra; 327 }; 328 329 int libbpf__bpf_create_map_xattr(const struct bpf_create_map_params *create_attr); 330 331 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); 332 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, 333 const char **prefix, int *kind); 334 335 struct btf_ext_info { 336 /* 337 * info points to the individual info section (e.g. func_info and 338 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 339 */ 340 void *info; 341 __u32 rec_size; 342 __u32 len; 343 }; 344 345 #define for_each_btf_ext_sec(seg, sec) \ 346 for (sec = (seg)->info; \ 347 (void *)sec < (seg)->info + (seg)->len; \ 348 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 349 (seg)->rec_size * sec->num_info) 350 351 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 352 for (i = 0, rec = (void *)&(sec)->data; \ 353 i < (sec)->num_info; \ 354 i++, rec = (void *)rec + (seg)->rec_size) 355 356 /* 357 * The .BTF.ext ELF section layout defined as 358 * struct btf_ext_header 359 * func_info subsection 360 * 361 * The func_info subsection layout: 362 * record size for struct bpf_func_info in the func_info subsection 363 * struct btf_sec_func_info for section #1 364 * a list of bpf_func_info records for section #1 365 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h 366 * but may not be identical 367 * struct btf_sec_func_info for section #2 368 * a list of bpf_func_info records for section #2 369 * ...... 370 * 371 * Note that the bpf_func_info record size in .BTF.ext may not 372 * be the same as the one defined in include/uapi/linux/bpf.h. 373 * The loader should ensure that record_size meets minimum 374 * requirement and pass the record as is to the kernel. The 375 * kernel will handle the func_info properly based on its contents. 376 */ 377 struct btf_ext_header { 378 __u16 magic; 379 __u8 version; 380 __u8 flags; 381 __u32 hdr_len; 382 383 /* All offsets are in bytes relative to the end of this header */ 384 __u32 func_info_off; 385 __u32 func_info_len; 386 __u32 line_info_off; 387 __u32 line_info_len; 388 389 /* optional part of .BTF.ext header */ 390 __u32 core_relo_off; 391 __u32 core_relo_len; 392 }; 393 394 struct btf_ext { 395 union { 396 struct btf_ext_header *hdr; 397 void *data; 398 }; 399 struct btf_ext_info func_info; 400 struct btf_ext_info line_info; 401 struct btf_ext_info core_relo_info; 402 __u32 data_size; 403 }; 404 405 struct btf_ext_info_sec { 406 __u32 sec_name_off; 407 __u32 num_info; 408 /* Followed by num_info * record_size number of bytes */ 409 __u8 data[]; 410 }; 411 412 /* The minimum bpf_func_info checked by the loader */ 413 struct bpf_func_info_min { 414 __u32 insn_off; 415 __u32 type_id; 416 }; 417 418 /* The minimum bpf_line_info checked by the loader */ 419 struct bpf_line_info_min { 420 __u32 insn_off; 421 __u32 file_name_off; 422 __u32 line_off; 423 __u32 line_col; 424 }; 425 426 427 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); 428 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); 429 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); 430 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); 431 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); 432 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); 433 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name, 434 __u32 kind); 435 436 extern enum libbpf_strict_mode libbpf_mode; 437 438 /* handle direct returned errors */ 439 static inline int libbpf_err(int ret) 440 { 441 if (ret < 0) 442 errno = -ret; 443 return ret; 444 } 445 446 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's 447 * strict mode settings 448 */ 449 static inline int libbpf_err_errno(int ret) 450 { 451 if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS) 452 /* errno is already assumed to be set on error */ 453 return ret < 0 ? -errno : ret; 454 455 /* legacy: on error return -1 directly and don't touch errno */ 456 return ret; 457 } 458 459 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */ 460 static inline void *libbpf_err_ptr(int err) 461 { 462 /* set errno on error, this doesn't break anything */ 463 errno = -err; 464 465 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) 466 return NULL; 467 468 /* legacy: encode err as ptr */ 469 return ERR_PTR(err); 470 } 471 472 /* handle pointer-returning APIs' error handling */ 473 static inline void *libbpf_ptr(void *ret) 474 { 475 /* set errno on error, this doesn't break anything */ 476 if (IS_ERR(ret)) 477 errno = -PTR_ERR(ret); 478 479 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS) 480 return IS_ERR(ret) ? NULL : ret; 481 482 /* legacy: pass-through original pointer */ 483 return ret; 484 } 485 486 static inline bool str_is_empty(const char *s) 487 { 488 return !s || !s[0]; 489 } 490 491 static inline bool is_ldimm64_insn(struct bpf_insn *insn) 492 { 493 return insn->code == (BPF_LD | BPF_IMM | BPF_DW); 494 } 495 496 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2 497 * Takes ownership of the fd passed in, and closes it if calling 498 * fcntl(fd, F_DUPFD_CLOEXEC, 3). 499 */ 500 static inline int ensure_good_fd(int fd) 501 { 502 int old_fd = fd, saved_errno; 503 504 if (fd < 0) 505 return fd; 506 if (fd < 3) { 507 fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); 508 saved_errno = errno; 509 close(old_fd); 510 if (fd < 0) { 511 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); 512 errno = saved_errno; 513 } 514 } 515 return fd; 516 } 517 518 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 519