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