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 15 /* make sure libbpf doesn't use kernel-only integer typedefs */ 16 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 17 18 /* prevent accidental re-addition of reallocarray() */ 19 #pragma GCC poison reallocarray 20 21 #include "libbpf.h" 22 #include "btf.h" 23 24 #ifndef EM_BPF 25 #define EM_BPF 247 26 #endif 27 28 #ifndef R_BPF_64_64 29 #define R_BPF_64_64 1 30 #endif 31 #ifndef R_BPF_64_32 32 #define R_BPF_64_32 10 33 #endif 34 35 #ifndef SHT_LLVM_ADDRSIG 36 #define SHT_LLVM_ADDRSIG 0x6FFF4C03 37 #endif 38 39 /* if libelf is old and doesn't support mmap(), fall back to read() */ 40 #ifndef ELF_C_READ_MMAP 41 #define ELF_C_READ_MMAP ELF_C_READ 42 #endif 43 44 /* Older libelf all end up in this expression, for both 32 and 64 bit */ 45 #ifndef GELF_ST_VISIBILITY 46 #define GELF_ST_VISIBILITY(o) ((o) & 0x03) 47 #endif 48 49 #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 50 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 51 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 52 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 53 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 54 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 55 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 56 BTF_INT_ENC(encoding, bits_offset, bits) 57 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 58 #define BTF_PARAM_ENC(name, type) (name), (type) 59 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 60 #define BTF_TYPE_FLOAT_ENC(name, sz) \ 61 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz) 62 63 #ifndef likely 64 #define likely(x) __builtin_expect(!!(x), 1) 65 #endif 66 #ifndef unlikely 67 #define unlikely(x) __builtin_expect(!!(x), 0) 68 #endif 69 #ifndef min 70 # define min(x, y) ((x) < (y) ? (x) : (y)) 71 #endif 72 #ifndef max 73 # define max(x, y) ((x) < (y) ? (y) : (x)) 74 #endif 75 #ifndef offsetofend 76 # define offsetofend(TYPE, FIELD) \ 77 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 78 #endif 79 80 /* Symbol versioning is different between static and shared library. 81 * Properly versioned symbols are needed for shared library, but 82 * only the symbol of the new version is needed for static library. 83 */ 84 #ifdef SHARED 85 # define COMPAT_VERSION(internal_name, api_name, version) \ 86 asm(".symver " #internal_name "," #api_name "@" #version); 87 # define DEFAULT_VERSION(internal_name, api_name, version) \ 88 asm(".symver " #internal_name "," #api_name "@@" #version); 89 #else 90 # define COMPAT_VERSION(internal_name, api_name, version) 91 # define DEFAULT_VERSION(internal_name, api_name, version) \ 92 extern typeof(internal_name) api_name \ 93 __attribute__((alias(#internal_name))); 94 #endif 95 96 extern void libbpf_print(enum libbpf_print_level level, 97 const char *format, ...) 98 __attribute__((format(printf, 2, 3))); 99 100 #define __pr(level, fmt, ...) \ 101 do { \ 102 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 103 } while (0) 104 105 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 106 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 107 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 108 109 #ifndef __has_builtin 110 #define __has_builtin(x) 0 111 #endif 112 /* 113 * Re-implement glibc's reallocarray() for libbpf internal-only use. 114 * reallocarray(), unfortunately, is not available in all versions of glibc, 115 * so requires extra feature detection and using reallocarray() stub from 116 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates 117 * build of libbpf unnecessarily and is just a maintenance burden. Instead, 118 * it's trivial to implement libbpf-specific internal version and use it 119 * throughout libbpf. 120 */ 121 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) 122 { 123 size_t total; 124 125 #if __has_builtin(__builtin_mul_overflow) 126 if (unlikely(__builtin_mul_overflow(nmemb, size, &total))) 127 return NULL; 128 #else 129 if (size == 0 || nmemb > ULONG_MAX / size) 130 return NULL; 131 total = nmemb * size; 132 #endif 133 return realloc(ptr, total); 134 } 135 136 struct btf; 137 struct btf_type; 138 139 struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id); 140 const char *btf_kind_str(const struct btf_type *t); 141 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); 142 143 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) 144 { 145 return (enum btf_func_linkage)(int)btf_vlen(t); 146 } 147 148 static inline __u32 btf_type_info(int kind, int vlen, int kflag) 149 { 150 return (kflag << 31) | (kind << 24) | vlen; 151 } 152 153 enum map_def_parts { 154 MAP_DEF_MAP_TYPE = 0x001, 155 MAP_DEF_KEY_TYPE = 0x002, 156 MAP_DEF_KEY_SIZE = 0x004, 157 MAP_DEF_VALUE_TYPE = 0x008, 158 MAP_DEF_VALUE_SIZE = 0x010, 159 MAP_DEF_MAX_ENTRIES = 0x020, 160 MAP_DEF_MAP_FLAGS = 0x040, 161 MAP_DEF_NUMA_NODE = 0x080, 162 MAP_DEF_PINNING = 0x100, 163 MAP_DEF_INNER_MAP = 0x200, 164 165 MAP_DEF_ALL = 0x3ff, /* combination of all above */ 166 }; 167 168 struct btf_map_def { 169 enum map_def_parts parts; 170 __u32 map_type; 171 __u32 key_type_id; 172 __u32 key_size; 173 __u32 value_type_id; 174 __u32 value_size; 175 __u32 max_entries; 176 __u32 map_flags; 177 __u32 numa_node; 178 __u32 pinning; 179 }; 180 181 int parse_btf_map_def(const char *map_name, struct btf *btf, 182 const struct btf_type *def_t, bool strict, 183 struct btf_map_def *map_def, struct btf_map_def *inner_def); 184 185 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, 186 size_t cur_cnt, size_t max_cnt, size_t add_cnt); 187 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); 188 189 static inline bool libbpf_validate_opts(const char *opts, 190 size_t opts_sz, size_t user_sz, 191 const char *type_name) 192 { 193 if (user_sz < sizeof(size_t)) { 194 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 195 return false; 196 } 197 if (user_sz > opts_sz) { 198 size_t i; 199 200 for (i = opts_sz; i < user_sz; i++) { 201 if (opts[i]) { 202 pr_warn("%s has non-zero extra bytes\n", 203 type_name); 204 return false; 205 } 206 } 207 } 208 return true; 209 } 210 211 #define OPTS_VALID(opts, type) \ 212 (!(opts) || libbpf_validate_opts((const char *)opts, \ 213 offsetofend(struct type, \ 214 type##__last_field), \ 215 (opts)->sz, #type)) 216 #define OPTS_HAS(opts, field) \ 217 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 218 #define OPTS_GET(opts, field, fallback_value) \ 219 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 220 #define OPTS_SET(opts, field, value) \ 221 do { \ 222 if (OPTS_HAS(opts, field)) \ 223 (opts)->field = value; \ 224 } while (0) 225 226 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 227 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 228 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 229 const char *str_sec, size_t str_len); 230 231 struct bpf_prog_load_params { 232 enum bpf_prog_type prog_type; 233 enum bpf_attach_type expected_attach_type; 234 const char *name; 235 const struct bpf_insn *insns; 236 size_t insn_cnt; 237 const char *license; 238 __u32 kern_version; 239 __u32 attach_prog_fd; 240 __u32 attach_btf_obj_fd; 241 __u32 attach_btf_id; 242 __u32 prog_ifindex; 243 __u32 prog_btf_fd; 244 __u32 prog_flags; 245 246 __u32 func_info_rec_size; 247 const void *func_info; 248 __u32 func_info_cnt; 249 250 __u32 line_info_rec_size; 251 const void *line_info; 252 __u32 line_info_cnt; 253 254 __u32 log_level; 255 char *log_buf; 256 size_t log_buf_sz; 257 }; 258 259 int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr); 260 261 int bpf_object__section_size(const struct bpf_object *obj, const char *name, 262 __u32 *size); 263 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, 264 __u32 *off); 265 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf); 266 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, 267 const char **prefix, int *kind); 268 269 struct btf_ext_info { 270 /* 271 * info points to the individual info section (e.g. func_info and 272 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 273 */ 274 void *info; 275 __u32 rec_size; 276 __u32 len; 277 }; 278 279 #define for_each_btf_ext_sec(seg, sec) \ 280 for (sec = (seg)->info; \ 281 (void *)sec < (seg)->info + (seg)->len; \ 282 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 283 (seg)->rec_size * sec->num_info) 284 285 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 286 for (i = 0, rec = (void *)&(sec)->data; \ 287 i < (sec)->num_info; \ 288 i++, rec = (void *)rec + (seg)->rec_size) 289 290 /* 291 * The .BTF.ext ELF section layout defined as 292 * struct btf_ext_header 293 * func_info subsection 294 * 295 * The func_info subsection layout: 296 * record size for struct bpf_func_info in the func_info subsection 297 * struct btf_sec_func_info for section #1 298 * a list of bpf_func_info records for section #1 299 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h 300 * but may not be identical 301 * struct btf_sec_func_info for section #2 302 * a list of bpf_func_info records for section #2 303 * ...... 304 * 305 * Note that the bpf_func_info record size in .BTF.ext may not 306 * be the same as the one defined in include/uapi/linux/bpf.h. 307 * The loader should ensure that record_size meets minimum 308 * requirement and pass the record as is to the kernel. The 309 * kernel will handle the func_info properly based on its contents. 310 */ 311 struct btf_ext_header { 312 __u16 magic; 313 __u8 version; 314 __u8 flags; 315 __u32 hdr_len; 316 317 /* All offsets are in bytes relative to the end of this header */ 318 __u32 func_info_off; 319 __u32 func_info_len; 320 __u32 line_info_off; 321 __u32 line_info_len; 322 323 /* optional part of .BTF.ext header */ 324 __u32 core_relo_off; 325 __u32 core_relo_len; 326 }; 327 328 struct btf_ext { 329 union { 330 struct btf_ext_header *hdr; 331 void *data; 332 }; 333 struct btf_ext_info func_info; 334 struct btf_ext_info line_info; 335 struct btf_ext_info core_relo_info; 336 __u32 data_size; 337 }; 338 339 struct btf_ext_info_sec { 340 __u32 sec_name_off; 341 __u32 num_info; 342 /* Followed by num_info * record_size number of bytes */ 343 __u8 data[]; 344 }; 345 346 /* The minimum bpf_func_info checked by the loader */ 347 struct bpf_func_info_min { 348 __u32 insn_off; 349 __u32 type_id; 350 }; 351 352 /* The minimum bpf_line_info checked by the loader */ 353 struct bpf_line_info_min { 354 __u32 insn_off; 355 __u32 file_name_off; 356 __u32 line_off; 357 __u32 line_col; 358 }; 359 360 /* bpf_core_relo_kind encodes which aspect of captured field/type/enum value 361 * has to be adjusted by relocations. 362 */ 363 enum bpf_core_relo_kind { 364 BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ 365 BPF_FIELD_BYTE_SIZE = 1, /* field size in bytes */ 366 BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ 367 BPF_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */ 368 BPF_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */ 369 BPF_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */ 370 BPF_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */ 371 BPF_TYPE_ID_TARGET = 7, /* type ID in target kernel */ 372 BPF_TYPE_EXISTS = 8, /* type existence in target kernel */ 373 BPF_TYPE_SIZE = 9, /* type size in bytes */ 374 BPF_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */ 375 BPF_ENUMVAL_VALUE = 11, /* enum value integer value */ 376 }; 377 378 /* The minimum bpf_core_relo checked by the loader 379 * 380 * CO-RE relocation captures the following data: 381 * - insn_off - instruction offset (in bytes) within a BPF program that needs 382 * its insn->imm field to be relocated with actual field info; 383 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable 384 * type or field; 385 * - access_str_off - offset into corresponding .BTF string section. String 386 * interpretation depends on specific relocation kind: 387 * - for field-based relocations, string encodes an accessed field using 388 * a sequence of field and array indices, separated by colon (:). It's 389 * conceptually very close to LLVM's getelementptr ([0]) instruction's 390 * arguments for identifying offset to a field. 391 * - for type-based relocations, strings is expected to be just "0"; 392 * - for enum value-based relocations, string contains an index of enum 393 * value within its enum type; 394 * 395 * Example to provide a better feel. 396 * 397 * struct sample { 398 * int a; 399 * struct { 400 * int b[10]; 401 * }; 402 * }; 403 * 404 * struct sample *s = ...; 405 * int x = &s->a; // encoded as "0:0" (a is field #0) 406 * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, 407 * // b is field #0 inside anon struct, accessing elem #5) 408 * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) 409 * 410 * type_id for all relocs in this example will capture BTF type id of 411 * `struct sample`. 412 * 413 * Such relocation is emitted when using __builtin_preserve_access_index() 414 * Clang built-in, passing expression that captures field address, e.g.: 415 * 416 * bpf_probe_read(&dst, sizeof(dst), 417 * __builtin_preserve_access_index(&src->a.b.c)); 418 * 419 * In this case Clang will emit field relocation recording necessary data to 420 * be able to find offset of embedded `a.b.c` field within `src` struct. 421 * 422 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction 423 */ 424 struct bpf_core_relo { 425 __u32 insn_off; 426 __u32 type_id; 427 __u32 access_str_off; 428 enum bpf_core_relo_kind kind; 429 }; 430 431 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx); 432 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx); 433 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx); 434 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx); 435 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx); 436 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx); 437 438 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 439