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