1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2/* Copyright (C) 2019 Facebook */ 3 4#ifndef _GNU_SOURCE 5#define _GNU_SOURCE 6#endif 7#include <ctype.h> 8#include <errno.h> 9#include <fcntl.h> 10#include <libgen.h> 11#include <linux/err.h> 12#include <stdbool.h> 13#include <stdio.h> 14#include <string.h> 15#include <unistd.h> 16#include <bpf/bpf.h> 17#include <bpf/libbpf.h> 18#include <bpf/libbpf_internal.h> 19#include <sys/types.h> 20#include <sys/stat.h> 21#include <sys/mman.h> 22#include <bpf/btf.h> 23 24#include "json_writer.h" 25#include "main.h" 26 27#define MAX_OBJ_NAME_LEN 64 28 29static void sanitize_identifier(char *name) 30{ 31 int i; 32 33 for (i = 0; name[i]; i++) 34 if (!isalnum(name[i]) && name[i] != '_') 35 name[i] = '_'; 36} 37 38static bool str_has_prefix(const char *str, const char *prefix) 39{ 40 return strncmp(str, prefix, strlen(prefix)) == 0; 41} 42 43static bool str_has_suffix(const char *str, const char *suffix) 44{ 45 size_t i, n1 = strlen(str), n2 = strlen(suffix); 46 47 if (n1 < n2) 48 return false; 49 50 for (i = 0; i < n2; i++) { 51 if (str[n1 - i - 1] != suffix[n2 - i - 1]) 52 return false; 53 } 54 55 return true; 56} 57 58static const struct btf_type * 59resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id) 60{ 61 const struct btf_type *t; 62 63 t = skip_mods_and_typedefs(btf, id, NULL); 64 if (!btf_is_ptr(t)) 65 return NULL; 66 67 t = skip_mods_and_typedefs(btf, t->type, res_id); 68 69 return btf_is_func_proto(t) ? t : NULL; 70} 71 72static void get_obj_name(char *name, const char *file) 73{ 74 char file_copy[PATH_MAX]; 75 76 /* Using basename() POSIX version to be more portable. */ 77 strncpy(file_copy, file, PATH_MAX - 1)[PATH_MAX - 1] = '\0'; 78 strncpy(name, basename(file_copy), MAX_OBJ_NAME_LEN - 1)[MAX_OBJ_NAME_LEN - 1] = '\0'; 79 if (str_has_suffix(name, ".o")) 80 name[strlen(name) - 2] = '\0'; 81 sanitize_identifier(name); 82} 83 84static void get_header_guard(char *guard, const char *obj_name, const char *suffix) 85{ 86 int i; 87 88 sprintf(guard, "__%s_%s__", obj_name, suffix); 89 for (i = 0; guard[i]; i++) 90 guard[i] = toupper(guard[i]); 91} 92 93static bool get_map_ident(const struct bpf_map *map, char *buf, size_t buf_sz) 94{ 95 static const char *sfxs[] = { ".data", ".rodata", ".bss", ".kconfig" }; 96 const char *name = bpf_map__name(map); 97 int i, n; 98 99 if (!bpf_map__is_internal(map)) { 100 snprintf(buf, buf_sz, "%s", name); 101 return true; 102 } 103 104 for (i = 0, n = ARRAY_SIZE(sfxs); i < n; i++) { 105 const char *sfx = sfxs[i], *p; 106 107 p = strstr(name, sfx); 108 if (p) { 109 snprintf(buf, buf_sz, "%s", p + 1); 110 sanitize_identifier(buf); 111 return true; 112 } 113 } 114 115 return false; 116} 117 118static bool get_datasec_ident(const char *sec_name, char *buf, size_t buf_sz) 119{ 120 static const char *pfxs[] = { ".data", ".rodata", ".bss", ".kconfig" }; 121 int i, n; 122 123 /* recognize hard coded LLVM section name */ 124 if (strcmp(sec_name, ".addr_space.1") == 0) { 125 /* this is the name to use in skeleton */ 126 snprintf(buf, buf_sz, "arena"); 127 return true; 128 } 129 for (i = 0, n = ARRAY_SIZE(pfxs); i < n; i++) { 130 const char *pfx = pfxs[i]; 131 132 if (str_has_prefix(sec_name, pfx)) { 133 snprintf(buf, buf_sz, "%s", sec_name + 1); 134 sanitize_identifier(buf); 135 return true; 136 } 137 } 138 139 return false; 140} 141 142static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args) 143{ 144 vprintf(fmt, args); 145} 146 147static int codegen_datasec_def(struct bpf_object *obj, 148 struct btf *btf, 149 struct btf_dump *d, 150 const struct btf_type *sec, 151 const char *obj_name) 152{ 153 const char *sec_name = btf__name_by_offset(btf, sec->name_off); 154 const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec); 155 int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec); 156 char var_ident[256], sec_ident[256]; 157 bool strip_mods = false; 158 159 if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident))) 160 return 0; 161 162 if (strcmp(sec_name, ".kconfig") != 0) 163 strip_mods = true; 164 165 printf(" struct %s__%s {\n", obj_name, sec_ident); 166 for (i = 0; i < vlen; i++, sec_var++) { 167 const struct btf_type *var = btf__type_by_id(btf, sec_var->type); 168 const char *var_name = btf__name_by_offset(btf, var->name_off); 169 DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, 170 .field_name = var_ident, 171 .indent_level = 2, 172 .strip_mods = strip_mods, 173 ); 174 int need_off = sec_var->offset, align_off, align; 175 __u32 var_type_id = var->type; 176 177 /* static variables are not exposed through BPF skeleton */ 178 if (btf_var(var)->linkage == BTF_VAR_STATIC) 179 continue; 180 181 if (off > need_off) { 182 p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n", 183 sec_name, i, need_off, off); 184 return -EINVAL; 185 } 186 187 align = btf__align_of(btf, var->type); 188 if (align <= 0) { 189 p_err("Failed to determine alignment of variable '%s': %d", 190 var_name, align); 191 return -EINVAL; 192 } 193 /* Assume 32-bit architectures when generating data section 194 * struct memory layout. Given bpftool can't know which target 195 * host architecture it's emitting skeleton for, we need to be 196 * conservative and assume 32-bit one to ensure enough padding 197 * bytes are generated for pointer and long types. This will 198 * still work correctly for 64-bit architectures, because in 199 * the worst case we'll generate unnecessary padding field, 200 * which on 64-bit architectures is not strictly necessary and 201 * would be handled by natural 8-byte alignment. But it still 202 * will be a correct memory layout, based on recorded offsets 203 * in BTF. 204 */ 205 if (align > 4) 206 align = 4; 207 208 align_off = (off + align - 1) / align * align; 209 if (align_off != need_off) { 210 printf("\t\tchar __pad%d[%d];\n", 211 pad_cnt, need_off - off); 212 pad_cnt++; 213 } 214 215 /* sanitize variable name, e.g., for static vars inside 216 * a function, it's name is '<function name>.<variable name>', 217 * which we'll turn into a '<function name>_<variable name>' 218 */ 219 var_ident[0] = '\0'; 220 strncat(var_ident, var_name, sizeof(var_ident) - 1); 221 sanitize_identifier(var_ident); 222 223 printf("\t\t"); 224 err = btf_dump__emit_type_decl(d, var_type_id, &opts); 225 if (err) 226 return err; 227 printf(";\n"); 228 229 off = sec_var->offset + sec_var->size; 230 } 231 printf(" } *%s;\n", sec_ident); 232 return 0; 233} 234 235static const struct btf_type *find_type_for_map(struct btf *btf, const char *map_ident) 236{ 237 int n = btf__type_cnt(btf), i; 238 char sec_ident[256]; 239 240 for (i = 1; i < n; i++) { 241 const struct btf_type *t = btf__type_by_id(btf, i); 242 const char *name; 243 244 if (!btf_is_datasec(t)) 245 continue; 246 247 name = btf__str_by_offset(btf, t->name_off); 248 if (!get_datasec_ident(name, sec_ident, sizeof(sec_ident))) 249 continue; 250 251 if (strcmp(sec_ident, map_ident) == 0) 252 return t; 253 } 254 return NULL; 255} 256 257static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz) 258{ 259 size_t tmp_sz; 260 261 if (bpf_map__type(map) == BPF_MAP_TYPE_ARENA && bpf_map__initial_value(map, &tmp_sz)) { 262 snprintf(buf, sz, "arena"); 263 return true; 264 } 265 266 if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE)) 267 return false; 268 269 if (!get_map_ident(map, buf, sz)) 270 return false; 271 272 return true; 273} 274 275static int codegen_datasecs(struct bpf_object *obj, const char *obj_name) 276{ 277 struct btf *btf = bpf_object__btf(obj); 278 struct btf_dump *d; 279 struct bpf_map *map; 280 const struct btf_type *sec; 281 char map_ident[256]; 282 int err = 0; 283 284 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL); 285 if (!d) 286 return -errno; 287 288 bpf_object__for_each_map(map, obj) { 289 /* only generate definitions for memory-mapped internal maps */ 290 if (!is_mmapable_map(map, map_ident, sizeof(map_ident))) 291 continue; 292 293 sec = find_type_for_map(btf, map_ident); 294 295 /* In some cases (e.g., sections like .rodata.cst16 containing 296 * compiler allocated string constants only) there will be 297 * special internal maps with no corresponding DATASEC BTF 298 * type. In such case, generate empty structs for each such 299 * map. It will still be memory-mapped and its contents 300 * accessible from user-space through BPF skeleton. 301 */ 302 if (!sec) { 303 printf(" struct %s__%s {\n", obj_name, map_ident); 304 printf(" } *%s;\n", map_ident); 305 } else { 306 err = codegen_datasec_def(obj, btf, d, sec, obj_name); 307 if (err) 308 goto out; 309 } 310 } 311 312 313out: 314 btf_dump__free(d); 315 return err; 316} 317 318static bool btf_is_ptr_to_func_proto(const struct btf *btf, 319 const struct btf_type *v) 320{ 321 return btf_is_ptr(v) && btf_is_func_proto(btf__type_by_id(btf, v->type)); 322} 323 324static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name) 325{ 326 struct btf *btf = bpf_object__btf(obj); 327 struct btf_dump *d; 328 struct bpf_map *map; 329 const struct btf_type *sec, *var; 330 const struct btf_var_secinfo *sec_var; 331 int i, err = 0, vlen; 332 char map_ident[256], sec_ident[256]; 333 bool strip_mods = false, needs_typeof = false; 334 const char *sec_name, *var_name; 335 __u32 var_type_id; 336 337 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL); 338 if (!d) 339 return -errno; 340 341 bpf_object__for_each_map(map, obj) { 342 /* only generate definitions for memory-mapped internal maps */ 343 if (!is_mmapable_map(map, map_ident, sizeof(map_ident))) 344 continue; 345 346 sec = find_type_for_map(btf, map_ident); 347 if (!sec) 348 continue; 349 350 sec_name = btf__name_by_offset(btf, sec->name_off); 351 if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident))) 352 continue; 353 354 strip_mods = strcmp(sec_name, ".kconfig") != 0; 355 printf(" struct %s__%s {\n", obj_name, sec_ident); 356 357 sec_var = btf_var_secinfos(sec); 358 vlen = btf_vlen(sec); 359 for (i = 0; i < vlen; i++, sec_var++) { 360 DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, 361 .indent_level = 2, 362 .strip_mods = strip_mods, 363 /* we'll print the name separately */ 364 .field_name = "", 365 ); 366 367 var = btf__type_by_id(btf, sec_var->type); 368 var_name = btf__name_by_offset(btf, var->name_off); 369 var_type_id = var->type; 370 371 /* static variables are not exposed through BPF skeleton */ 372 if (btf_var(var)->linkage == BTF_VAR_STATIC) 373 continue; 374 375 /* The datasec member has KIND_VAR but we want the 376 * underlying type of the variable (e.g. KIND_INT). 377 */ 378 var = skip_mods_and_typedefs(btf, var->type, NULL); 379 380 printf("\t\t"); 381 /* Func and array members require special handling. 382 * Instead of producing `typename *var`, they produce 383 * `typeof(typename) *var`. This allows us to keep a 384 * similar syntax where the identifier is just prefixed 385 * by *, allowing us to ignore C declaration minutiae. 386 */ 387 needs_typeof = btf_is_array(var) || btf_is_ptr_to_func_proto(btf, var); 388 if (needs_typeof) 389 printf("typeof("); 390 391 err = btf_dump__emit_type_decl(d, var_type_id, &opts); 392 if (err) 393 goto out; 394 395 if (needs_typeof) 396 printf(")"); 397 398 printf(" *%s;\n", var_name); 399 } 400 printf(" } %s;\n", sec_ident); 401 } 402 403out: 404 btf_dump__free(d); 405 return err; 406} 407 408static void codegen(const char *template, ...) 409{ 410 const char *src, *end; 411 int skip_tabs = 0, n; 412 char *s, *dst; 413 va_list args; 414 char c; 415 416 n = strlen(template); 417 s = malloc(n + 1); 418 if (!s) 419 exit(-1); 420 src = template; 421 dst = s; 422 423 /* find out "baseline" indentation to skip */ 424 while ((c = *src++)) { 425 if (c == '\t') { 426 skip_tabs++; 427 } else if (c == '\n') { 428 break; 429 } else { 430 p_err("unrecognized character at pos %td in template '%s': '%c'", 431 src - template - 1, template, c); 432 free(s); 433 exit(-1); 434 } 435 } 436 437 while (*src) { 438 /* skip baseline indentation tabs */ 439 for (n = skip_tabs; n > 0; n--, src++) { 440 if (*src != '\t') { 441 p_err("not enough tabs at pos %td in template '%s'", 442 src - template - 1, template); 443 free(s); 444 exit(-1); 445 } 446 } 447 /* trim trailing whitespace */ 448 end = strchrnul(src, '\n'); 449 for (n = end - src; n > 0 && isspace(src[n - 1]); n--) 450 ; 451 memcpy(dst, src, n); 452 dst += n; 453 if (*end) 454 *dst++ = '\n'; 455 src = *end ? end + 1 : end; 456 } 457 *dst++ = '\0'; 458 459 /* print out using adjusted template */ 460 va_start(args, template); 461 n = vprintf(s, args); 462 va_end(args); 463 464 free(s); 465} 466 467static void print_hex(const char *data, int data_sz) 468{ 469 int i, len; 470 471 for (i = 0, len = 0; i < data_sz; i++) { 472 int w = data[i] ? 4 : 2; 473 474 len += w; 475 if (len > 78) { 476 printf("\\\n"); 477 len = w; 478 } 479 if (!data[i]) 480 printf("\\0"); 481 else 482 printf("\\x%02x", (unsigned char)data[i]); 483 } 484} 485 486static size_t bpf_map_mmap_sz(const struct bpf_map *map) 487{ 488 long page_sz = sysconf(_SC_PAGE_SIZE); 489 size_t map_sz; 490 491 map_sz = (size_t)roundup(bpf_map__value_size(map), 8) * bpf_map__max_entries(map); 492 map_sz = roundup(map_sz, page_sz); 493 return map_sz; 494} 495 496/* Emit type size asserts for all top-level fields in memory-mapped internal maps. */ 497static void codegen_asserts(struct bpf_object *obj, const char *obj_name) 498{ 499 struct btf *btf = bpf_object__btf(obj); 500 struct bpf_map *map; 501 struct btf_var_secinfo *sec_var; 502 int i, vlen; 503 const struct btf_type *sec; 504 char map_ident[256], var_ident[256]; 505 506 if (!btf) 507 return; 508 509 codegen("\ 510 \n\ 511 __attribute__((unused)) static void \n\ 512 %1$s__assert(struct %1$s *s __attribute__((unused))) \n\ 513 { \n\ 514 #ifdef __cplusplus \n\ 515 #define _Static_assert static_assert \n\ 516 #endif \n\ 517 ", obj_name); 518 519 bpf_object__for_each_map(map, obj) { 520 if (!is_mmapable_map(map, map_ident, sizeof(map_ident))) 521 continue; 522 523 sec = find_type_for_map(btf, map_ident); 524 if (!sec) { 525 /* best effort, couldn't find the type for this map */ 526 continue; 527 } 528 529 sec_var = btf_var_secinfos(sec); 530 vlen = btf_vlen(sec); 531 532 for (i = 0; i < vlen; i++, sec_var++) { 533 const struct btf_type *var = btf__type_by_id(btf, sec_var->type); 534 const char *var_name = btf__name_by_offset(btf, var->name_off); 535 long var_size; 536 537 /* static variables are not exposed through BPF skeleton */ 538 if (btf_var(var)->linkage == BTF_VAR_STATIC) 539 continue; 540 541 var_size = btf__resolve_size(btf, var->type); 542 if (var_size < 0) 543 continue; 544 545 var_ident[0] = '\0'; 546 strncat(var_ident, var_name, sizeof(var_ident) - 1); 547 sanitize_identifier(var_ident); 548 549 printf("\t_Static_assert(sizeof(s->%s->%s) == %ld, \"unexpected size of '%s'\");\n", 550 map_ident, var_ident, var_size, var_ident); 551 } 552 } 553 codegen("\ 554 \n\ 555 #ifdef __cplusplus \n\ 556 #undef _Static_assert \n\ 557 #endif \n\ 558 } \n\ 559 "); 560} 561 562static void codegen_attach_detach(struct bpf_object *obj, const char *obj_name) 563{ 564 struct bpf_program *prog; 565 566 bpf_object__for_each_program(prog, obj) { 567 const char *tp_name; 568 569 codegen("\ 570 \n\ 571 \n\ 572 static inline int \n\ 573 %1$s__%2$s__attach(struct %1$s *skel) \n\ 574 { \n\ 575 int prog_fd = skel->progs.%2$s.prog_fd; \n\ 576 ", obj_name, bpf_program__name(prog)); 577 578 switch (bpf_program__type(prog)) { 579 case BPF_PROG_TYPE_RAW_TRACEPOINT: 580 tp_name = strchr(bpf_program__section_name(prog), '/') + 1; 581 printf("\tint fd = skel_raw_tracepoint_open(\"%s\", prog_fd);\n", tp_name); 582 break; 583 case BPF_PROG_TYPE_TRACING: 584 case BPF_PROG_TYPE_LSM: 585 if (bpf_program__expected_attach_type(prog) == BPF_TRACE_ITER) 586 printf("\tint fd = skel_link_create(prog_fd, 0, BPF_TRACE_ITER);\n"); 587 else 588 printf("\tint fd = skel_raw_tracepoint_open(NULL, prog_fd);\n"); 589 break; 590 default: 591 printf("\tint fd = ((void)prog_fd, 0); /* auto-attach not supported */\n"); 592 break; 593 } 594 codegen("\ 595 \n\ 596 \n\ 597 if (fd > 0) \n\ 598 skel->links.%1$s_fd = fd; \n\ 599 return fd; \n\ 600 } \n\ 601 ", bpf_program__name(prog)); 602 } 603 604 codegen("\ 605 \n\ 606 \n\ 607 static inline int \n\ 608 %1$s__attach(struct %1$s *skel) \n\ 609 { \n\ 610 int ret = 0; \n\ 611 \n\ 612 ", obj_name); 613 614 bpf_object__for_each_program(prog, obj) { 615 codegen("\ 616 \n\ 617 ret = ret < 0 ? ret : %1$s__%2$s__attach(skel); \n\ 618 ", obj_name, bpf_program__name(prog)); 619 } 620 621 codegen("\ 622 \n\ 623 return ret < 0 ? ret : 0; \n\ 624 } \n\ 625 \n\ 626 static inline void \n\ 627 %1$s__detach(struct %1$s *skel) \n\ 628 { \n\ 629 ", obj_name); 630 631 bpf_object__for_each_program(prog, obj) { 632 codegen("\ 633 \n\ 634 skel_closenz(skel->links.%1$s_fd); \n\ 635 ", bpf_program__name(prog)); 636 } 637 638 codegen("\ 639 \n\ 640 } \n\ 641 "); 642} 643 644static void codegen_destroy(struct bpf_object *obj, const char *obj_name) 645{ 646 struct bpf_program *prog; 647 struct bpf_map *map; 648 char ident[256]; 649 650 codegen("\ 651 \n\ 652 static void \n\ 653 %1$s__destroy(struct %1$s *skel) \n\ 654 { \n\ 655 if (!skel) \n\ 656 return; \n\ 657 %1$s__detach(skel); \n\ 658 ", 659 obj_name); 660 661 bpf_object__for_each_program(prog, obj) { 662 codegen("\ 663 \n\ 664 skel_closenz(skel->progs.%1$s.prog_fd); \n\ 665 ", bpf_program__name(prog)); 666 } 667 668 bpf_object__for_each_map(map, obj) { 669 if (!get_map_ident(map, ident, sizeof(ident))) 670 continue; 671 if (bpf_map__is_internal(map) && 672 (bpf_map__map_flags(map) & BPF_F_MMAPABLE)) 673 printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n", 674 ident, bpf_map_mmap_sz(map)); 675 codegen("\ 676 \n\ 677 skel_closenz(skel->maps.%1$s.map_fd); \n\ 678 ", ident); 679 } 680 codegen("\ 681 \n\ 682 skel_free(skel); \n\ 683 } \n\ 684 ", 685 obj_name); 686} 687 688static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard) 689{ 690 DECLARE_LIBBPF_OPTS(gen_loader_opts, opts); 691 struct bpf_map *map; 692 char ident[256]; 693 int err = 0; 694 695 err = bpf_object__gen_loader(obj, &opts); 696 if (err) 697 return err; 698 699 err = bpf_object__load(obj); 700 if (err) { 701 p_err("failed to load object file"); 702 goto out; 703 } 704 /* If there was no error during load then gen_loader_opts 705 * are populated with the loader program. 706 */ 707 708 /* finish generating 'struct skel' */ 709 codegen("\ 710 \n\ 711 }; \n\ 712 ", obj_name); 713 714 715 codegen_attach_detach(obj, obj_name); 716 717 codegen_destroy(obj, obj_name); 718 719 codegen("\ 720 \n\ 721 static inline struct %1$s * \n\ 722 %1$s__open(void) \n\ 723 { \n\ 724 struct %1$s *skel; \n\ 725 \n\ 726 skel = skel_alloc(sizeof(*skel)); \n\ 727 if (!skel) \n\ 728 goto cleanup; \n\ 729 skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\ 730 ", 731 obj_name, opts.data_sz); 732 bpf_object__for_each_map(map, obj) { 733 const void *mmap_data = NULL; 734 size_t mmap_size = 0; 735 736 if (!is_mmapable_map(map, ident, sizeof(ident))) 737 continue; 738 739 codegen("\ 740 \n\ 741 { \n\ 742 static const char data[] __attribute__((__aligned__(8))) = \"\\\n\ 743 "); 744 mmap_data = bpf_map__initial_value(map, &mmap_size); 745 print_hex(mmap_data, mmap_size); 746 codegen("\ 747 \n\ 748 \"; \n\ 749 \n\ 750 skel->%1$s = skel_prep_map_data((void *)data, %2$zd,\n\ 751 sizeof(data) - 1);\n\ 752 if (!skel->%1$s) \n\ 753 goto cleanup; \n\ 754 skel->maps.%1$s.initial_value = (__u64) (long) skel->%1$s;\n\ 755 } \n\ 756 ", ident, bpf_map_mmap_sz(map)); 757 } 758 codegen("\ 759 \n\ 760 return skel; \n\ 761 cleanup: \n\ 762 %1$s__destroy(skel); \n\ 763 return NULL; \n\ 764 } \n\ 765 \n\ 766 static inline int \n\ 767 %1$s__load(struct %1$s *skel) \n\ 768 { \n\ 769 struct bpf_load_and_run_opts opts = {}; \n\ 770 int err; \n\ 771 static const char opts_data[] __attribute__((__aligned__(8))) = \"\\\n\ 772 ", 773 obj_name); 774 print_hex(opts.data, opts.data_sz); 775 codegen("\ 776 \n\ 777 \"; \n\ 778 static const char opts_insn[] __attribute__((__aligned__(8))) = \"\\\n\ 779 "); 780 print_hex(opts.insns, opts.insns_sz); 781 codegen("\ 782 \n\ 783 \"; \n\ 784 \n\ 785 opts.ctx = (struct bpf_loader_ctx *)skel; \n\ 786 opts.data_sz = sizeof(opts_data) - 1; \n\ 787 opts.data = (void *)opts_data; \n\ 788 opts.insns_sz = sizeof(opts_insn) - 1; \n\ 789 opts.insns = (void *)opts_insn; \n\ 790 \n\ 791 err = bpf_load_and_run(&opts); \n\ 792 if (err < 0) \n\ 793 return err; \n\ 794 "); 795 bpf_object__for_each_map(map, obj) { 796 const char *mmap_flags; 797 798 if (!is_mmapable_map(map, ident, sizeof(ident))) 799 continue; 800 801 if (bpf_map__map_flags(map) & BPF_F_RDONLY_PROG) 802 mmap_flags = "PROT_READ"; 803 else 804 mmap_flags = "PROT_READ | PROT_WRITE"; 805 806 codegen("\ 807 \n\ 808 skel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value, \n\ 809 %2$zd, %3$s, skel->maps.%1$s.map_fd);\n\ 810 if (!skel->%1$s) \n\ 811 return -ENOMEM; \n\ 812 ", 813 ident, bpf_map_mmap_sz(map), mmap_flags); 814 } 815 codegen("\ 816 \n\ 817 return 0; \n\ 818 } \n\ 819 \n\ 820 static inline struct %1$s * \n\ 821 %1$s__open_and_load(void) \n\ 822 { \n\ 823 struct %1$s *skel; \n\ 824 \n\ 825 skel = %1$s__open(); \n\ 826 if (!skel) \n\ 827 return NULL; \n\ 828 if (%1$s__load(skel)) { \n\ 829 %1$s__destroy(skel); \n\ 830 return NULL; \n\ 831 } \n\ 832 return skel; \n\ 833 } \n\ 834 \n\ 835 ", obj_name); 836 837 codegen_asserts(obj, obj_name); 838 839 codegen("\ 840 \n\ 841 \n\ 842 #endif /* %s */ \n\ 843 ", 844 header_guard); 845 err = 0; 846out: 847 return err; 848} 849 850static void 851codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped) 852{ 853 struct bpf_map *map; 854 char ident[256]; 855 size_t i; 856 857 if (!map_cnt) 858 return; 859 860 codegen("\ 861 \n\ 862 \n\ 863 /* maps */ \n\ 864 s->map_cnt = %zu; \n\ 865 s->map_skel_sz = sizeof(*s->maps); \n\ 866 s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\ 867 if (!s->maps) { \n\ 868 err = -ENOMEM; \n\ 869 goto err; \n\ 870 } \n\ 871 ", 872 map_cnt 873 ); 874 i = 0; 875 bpf_object__for_each_map(map, obj) { 876 if (!get_map_ident(map, ident, sizeof(ident))) 877 continue; 878 879 codegen("\ 880 \n\ 881 \n\ 882 s->maps[%zu].name = \"%s\"; \n\ 883 s->maps[%zu].map = &obj->maps.%s; \n\ 884 ", 885 i, bpf_map__name(map), i, ident); 886 /* memory-mapped internal maps */ 887 if (mmaped && is_mmapable_map(map, ident, sizeof(ident))) { 888 printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n", 889 i, ident); 890 } 891 i++; 892 } 893} 894 895static void 896codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_links) 897{ 898 struct bpf_program *prog; 899 int i; 900 901 if (!prog_cnt) 902 return; 903 904 codegen("\ 905 \n\ 906 \n\ 907 /* programs */ \n\ 908 s->prog_cnt = %zu; \n\ 909 s->prog_skel_sz = sizeof(*s->progs); \n\ 910 s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\ 911 if (!s->progs) { \n\ 912 err = -ENOMEM; \n\ 913 goto err; \n\ 914 } \n\ 915 ", 916 prog_cnt 917 ); 918 i = 0; 919 bpf_object__for_each_program(prog, obj) { 920 codegen("\ 921 \n\ 922 \n\ 923 s->progs[%1$zu].name = \"%2$s\"; \n\ 924 s->progs[%1$zu].prog = &obj->progs.%2$s;\n\ 925 ", 926 i, bpf_program__name(prog)); 927 928 if (populate_links) { 929 codegen("\ 930 \n\ 931 s->progs[%1$zu].link = &obj->links.%2$s;\n\ 932 ", 933 i, bpf_program__name(prog)); 934 } 935 i++; 936 } 937} 938 939static int walk_st_ops_shadow_vars(struct btf *btf, const char *ident, 940 const struct btf_type *map_type, __u32 map_type_id) 941{ 942 LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts, .indent_level = 3); 943 const struct btf_type *member_type; 944 __u32 offset, next_offset = 0; 945 const struct btf_member *m; 946 struct btf_dump *d = NULL; 947 const char *member_name; 948 __u32 member_type_id; 949 int i, err = 0, n; 950 int size; 951 952 d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL); 953 if (!d) 954 return -errno; 955 956 n = btf_vlen(map_type); 957 for (i = 0, m = btf_members(map_type); i < n; i++, m++) { 958 member_type = skip_mods_and_typedefs(btf, m->type, &member_type_id); 959 member_name = btf__name_by_offset(btf, m->name_off); 960 961 offset = m->offset / 8; 962 if (next_offset < offset) 963 printf("\t\t\tchar __padding_%d[%d];\n", i, offset - next_offset); 964 965 switch (btf_kind(member_type)) { 966 case BTF_KIND_INT: 967 case BTF_KIND_FLOAT: 968 case BTF_KIND_ENUM: 969 case BTF_KIND_ENUM64: 970 /* scalar type */ 971 printf("\t\t\t"); 972 opts.field_name = member_name; 973 err = btf_dump__emit_type_decl(d, member_type_id, &opts); 974 if (err) { 975 p_err("Failed to emit type declaration for %s: %d", member_name, err); 976 goto out; 977 } 978 printf(";\n"); 979 980 size = btf__resolve_size(btf, member_type_id); 981 if (size < 0) { 982 p_err("Failed to resolve size of %s: %d\n", member_name, size); 983 err = size; 984 goto out; 985 } 986 987 next_offset = offset + size; 988 break; 989 990 case BTF_KIND_PTR: 991 if (resolve_func_ptr(btf, m->type, NULL)) { 992 /* Function pointer */ 993 printf("\t\t\tstruct bpf_program *%s;\n", member_name); 994 995 next_offset = offset + sizeof(void *); 996 break; 997 } 998 /* All pointer types are unsupported except for 999 * function pointers. 1000 */ 1001 fallthrough; 1002 1003 default: 1004 /* Unsupported types 1005 * 1006 * Types other than scalar types and function 1007 * pointers are currently not supported in order to 1008 * prevent conflicts in the generated code caused 1009 * by multiple definitions. For instance, if the 1010 * struct type FOO is used in a struct_ops map, 1011 * bpftool has to generate definitions for FOO, 1012 * which may result in conflicts if FOO is defined 1013 * in different skeleton files. 1014 */ 1015 size = btf__resolve_size(btf, member_type_id); 1016 if (size < 0) { 1017 p_err("Failed to resolve size of %s: %d\n", member_name, size); 1018 err = size; 1019 goto out; 1020 } 1021 printf("\t\t\tchar __unsupported_%d[%d];\n", i, size); 1022 1023 next_offset = offset + size; 1024 break; 1025 } 1026 } 1027 1028 /* Cannot fail since it must be a struct type */ 1029 size = btf__resolve_size(btf, map_type_id); 1030 if (next_offset < (__u32)size) 1031 printf("\t\t\tchar __padding_end[%d];\n", size - next_offset); 1032 1033out: 1034 btf_dump__free(d); 1035 1036 return err; 1037} 1038 1039/* Generate the pointer of the shadow type for a struct_ops map. 1040 * 1041 * This function adds a pointer of the shadow type for a struct_ops map. 1042 * The members of a struct_ops map can be exported through a pointer to a 1043 * shadow type. The user can access these members through the pointer. 1044 * 1045 * A shadow type includes not all members, only members of some types. 1046 * They are scalar types and function pointers. The function pointers are 1047 * translated to the pointer of the struct bpf_program. The scalar types 1048 * are translated to the original type without any modifiers. 1049 * 1050 * Unsupported types will be translated to a char array to occupy the same 1051 * space as the original field, being renamed as __unsupported_*. The user 1052 * should treat these fields as opaque data. 1053 */ 1054static int gen_st_ops_shadow_type(const char *obj_name, struct btf *btf, const char *ident, 1055 const struct bpf_map *map) 1056{ 1057 const struct btf_type *map_type; 1058 const char *type_name; 1059 __u32 map_type_id; 1060 int err; 1061 1062 map_type_id = bpf_map__btf_value_type_id(map); 1063 if (map_type_id == 0) 1064 return -EINVAL; 1065 map_type = btf__type_by_id(btf, map_type_id); 1066 if (!map_type) 1067 return -EINVAL; 1068 1069 type_name = btf__name_by_offset(btf, map_type->name_off); 1070 1071 printf("\t\tstruct %s__%s__%s {\n", obj_name, ident, type_name); 1072 1073 err = walk_st_ops_shadow_vars(btf, ident, map_type, map_type_id); 1074 if (err) 1075 return err; 1076 1077 printf("\t\t} *%s;\n", ident); 1078 1079 return 0; 1080} 1081 1082static int gen_st_ops_shadow(const char *obj_name, struct btf *btf, struct bpf_object *obj) 1083{ 1084 int err, st_ops_cnt = 0; 1085 struct bpf_map *map; 1086 char ident[256]; 1087 1088 if (!btf) 1089 return 0; 1090 1091 /* Generate the pointers to shadow types of 1092 * struct_ops maps. 1093 */ 1094 bpf_object__for_each_map(map, obj) { 1095 if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS) 1096 continue; 1097 if (!get_map_ident(map, ident, sizeof(ident))) 1098 continue; 1099 1100 if (st_ops_cnt == 0) /* first struct_ops map */ 1101 printf("\tstruct {\n"); 1102 st_ops_cnt++; 1103 1104 err = gen_st_ops_shadow_type(obj_name, btf, ident, map); 1105 if (err) 1106 return err; 1107 } 1108 1109 if (st_ops_cnt) 1110 printf("\t} struct_ops;\n"); 1111 1112 return 0; 1113} 1114 1115/* Generate the code to initialize the pointers of shadow types. */ 1116static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj) 1117{ 1118 struct bpf_map *map; 1119 char ident[256]; 1120 1121 if (!btf) 1122 return; 1123 1124 /* Initialize the pointers to_ops shadow types of 1125 * struct_ops maps. 1126 */ 1127 bpf_object__for_each_map(map, obj) { 1128 if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS) 1129 continue; 1130 if (!get_map_ident(map, ident, sizeof(ident))) 1131 continue; 1132 codegen("\ 1133 \n\ 1134 obj->struct_ops.%1$s = bpf_map__initial_value(obj->maps.%1$s, NULL);\n\ 1135 \n\ 1136 ", ident); 1137 } 1138} 1139 1140static int do_skeleton(int argc, char **argv) 1141{ 1142 char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")]; 1143 size_t map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz; 1144 DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts); 1145 char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data; 1146 struct bpf_object *obj = NULL; 1147 const char *file; 1148 char ident[256]; 1149 struct bpf_program *prog; 1150 int fd, err = -1; 1151 struct bpf_map *map; 1152 struct btf *btf; 1153 struct stat st; 1154 1155 if (!REQ_ARGS(1)) { 1156 usage(); 1157 return -1; 1158 } 1159 file = GET_ARG(); 1160 1161 while (argc) { 1162 if (!REQ_ARGS(2)) 1163 return -1; 1164 1165 if (is_prefix(*argv, "name")) { 1166 NEXT_ARG(); 1167 1168 if (obj_name[0] != '\0') { 1169 p_err("object name already specified"); 1170 return -1; 1171 } 1172 1173 strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1); 1174 obj_name[MAX_OBJ_NAME_LEN - 1] = '\0'; 1175 } else { 1176 p_err("unknown arg %s", *argv); 1177 return -1; 1178 } 1179 1180 NEXT_ARG(); 1181 } 1182 1183 if (argc) { 1184 p_err("extra unknown arguments"); 1185 return -1; 1186 } 1187 1188 if (stat(file, &st)) { 1189 p_err("failed to stat() %s: %s", file, strerror(errno)); 1190 return -1; 1191 } 1192 file_sz = st.st_size; 1193 mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE)); 1194 fd = open(file, O_RDONLY); 1195 if (fd < 0) { 1196 p_err("failed to open() %s: %s", file, strerror(errno)); 1197 return -1; 1198 } 1199 obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0); 1200 if (obj_data == MAP_FAILED) { 1201 obj_data = NULL; 1202 p_err("failed to mmap() %s: %s", file, strerror(errno)); 1203 goto out; 1204 } 1205 if (obj_name[0] == '\0') 1206 get_obj_name(obj_name, file); 1207 opts.object_name = obj_name; 1208 if (verifier_logs) 1209 /* log_level1 + log_level2 + stats, but not stable UAPI */ 1210 opts.kernel_log_level = 1 + 2 + 4; 1211 obj = bpf_object__open_mem(obj_data, file_sz, &opts); 1212 if (!obj) { 1213 char err_buf[256]; 1214 1215 err = -errno; 1216 libbpf_strerror(err, err_buf, sizeof(err_buf)); 1217 p_err("failed to open BPF object file: %s", err_buf); 1218 goto out; 1219 } 1220 1221 bpf_object__for_each_map(map, obj) { 1222 if (!get_map_ident(map, ident, sizeof(ident))) { 1223 p_err("ignoring unrecognized internal map '%s'...", 1224 bpf_map__name(map)); 1225 continue; 1226 } 1227 map_cnt++; 1228 } 1229 bpf_object__for_each_program(prog, obj) { 1230 prog_cnt++; 1231 } 1232 1233 get_header_guard(header_guard, obj_name, "SKEL_H"); 1234 if (use_loader) { 1235 codegen("\ 1236 \n\ 1237 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ 1238 /* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ \n\ 1239 #ifndef %2$s \n\ 1240 #define %2$s \n\ 1241 \n\ 1242 #include <bpf/skel_internal.h> \n\ 1243 \n\ 1244 struct %1$s { \n\ 1245 struct bpf_loader_ctx ctx; \n\ 1246 ", 1247 obj_name, header_guard 1248 ); 1249 } else { 1250 codegen("\ 1251 \n\ 1252 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ 1253 \n\ 1254 /* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ \n\ 1255 #ifndef %2$s \n\ 1256 #define %2$s \n\ 1257 \n\ 1258 #include <errno.h> \n\ 1259 #include <stdlib.h> \n\ 1260 #include <bpf/libbpf.h> \n\ 1261 \n\ 1262 struct %1$s { \n\ 1263 struct bpf_object_skeleton *skeleton; \n\ 1264 struct bpf_object *obj; \n\ 1265 ", 1266 obj_name, header_guard 1267 ); 1268 } 1269 1270 if (map_cnt) { 1271 printf("\tstruct {\n"); 1272 bpf_object__for_each_map(map, obj) { 1273 if (!get_map_ident(map, ident, sizeof(ident))) 1274 continue; 1275 if (use_loader) 1276 printf("\t\tstruct bpf_map_desc %s;\n", ident); 1277 else 1278 printf("\t\tstruct bpf_map *%s;\n", ident); 1279 } 1280 printf("\t} maps;\n"); 1281 } 1282 1283 btf = bpf_object__btf(obj); 1284 err = gen_st_ops_shadow(obj_name, btf, obj); 1285 if (err) 1286 goto out; 1287 1288 if (prog_cnt) { 1289 printf("\tstruct {\n"); 1290 bpf_object__for_each_program(prog, obj) { 1291 if (use_loader) 1292 printf("\t\tstruct bpf_prog_desc %s;\n", 1293 bpf_program__name(prog)); 1294 else 1295 printf("\t\tstruct bpf_program *%s;\n", 1296 bpf_program__name(prog)); 1297 } 1298 printf("\t} progs;\n"); 1299 printf("\tstruct {\n"); 1300 bpf_object__for_each_program(prog, obj) { 1301 if (use_loader) 1302 printf("\t\tint %s_fd;\n", 1303 bpf_program__name(prog)); 1304 else 1305 printf("\t\tstruct bpf_link *%s;\n", 1306 bpf_program__name(prog)); 1307 } 1308 printf("\t} links;\n"); 1309 } 1310 1311 if (btf) { 1312 err = codegen_datasecs(obj, obj_name); 1313 if (err) 1314 goto out; 1315 } 1316 if (use_loader) { 1317 err = gen_trace(obj, obj_name, header_guard); 1318 goto out; 1319 } 1320 1321 codegen("\ 1322 \n\ 1323 \n\ 1324 #ifdef __cplusplus \n\ 1325 static inline struct %1$s *open(const struct bpf_object_open_opts *opts = nullptr);\n\ 1326 static inline struct %1$s *open_and_load(); \n\ 1327 static inline int load(struct %1$s *skel); \n\ 1328 static inline int attach(struct %1$s *skel); \n\ 1329 static inline void detach(struct %1$s *skel); \n\ 1330 static inline void destroy(struct %1$s *skel); \n\ 1331 static inline const void *elf_bytes(size_t *sz); \n\ 1332 #endif /* __cplusplus */ \n\ 1333 }; \n\ 1334 \n\ 1335 static void \n\ 1336 %1$s__destroy(struct %1$s *obj) \n\ 1337 { \n\ 1338 if (!obj) \n\ 1339 return; \n\ 1340 if (obj->skeleton) \n\ 1341 bpf_object__destroy_skeleton(obj->skeleton);\n\ 1342 free(obj); \n\ 1343 } \n\ 1344 \n\ 1345 static inline int \n\ 1346 %1$s__create_skeleton(struct %1$s *obj); \n\ 1347 \n\ 1348 static inline struct %1$s * \n\ 1349 %1$s__open_opts(const struct bpf_object_open_opts *opts) \n\ 1350 { \n\ 1351 struct %1$s *obj; \n\ 1352 int err; \n\ 1353 \n\ 1354 obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\ 1355 if (!obj) { \n\ 1356 errno = ENOMEM; \n\ 1357 return NULL; \n\ 1358 } \n\ 1359 \n\ 1360 err = %1$s__create_skeleton(obj); \n\ 1361 if (err) \n\ 1362 goto err_out; \n\ 1363 \n\ 1364 err = bpf_object__open_skeleton(obj->skeleton, opts);\n\ 1365 if (err) \n\ 1366 goto err_out; \n\ 1367 \n\ 1368 ", obj_name); 1369 1370 gen_st_ops_shadow_init(btf, obj); 1371 1372 codegen("\ 1373 \n\ 1374 return obj; \n\ 1375 err_out: \n\ 1376 %1$s__destroy(obj); \n\ 1377 errno = -err; \n\ 1378 return NULL; \n\ 1379 } \n\ 1380 \n\ 1381 static inline struct %1$s * \n\ 1382 %1$s__open(void) \n\ 1383 { \n\ 1384 return %1$s__open_opts(NULL); \n\ 1385 } \n\ 1386 \n\ 1387 static inline int \n\ 1388 %1$s__load(struct %1$s *obj) \n\ 1389 { \n\ 1390 return bpf_object__load_skeleton(obj->skeleton); \n\ 1391 } \n\ 1392 \n\ 1393 static inline struct %1$s * \n\ 1394 %1$s__open_and_load(void) \n\ 1395 { \n\ 1396 struct %1$s *obj; \n\ 1397 int err; \n\ 1398 \n\ 1399 obj = %1$s__open(); \n\ 1400 if (!obj) \n\ 1401 return NULL; \n\ 1402 err = %1$s__load(obj); \n\ 1403 if (err) { \n\ 1404 %1$s__destroy(obj); \n\ 1405 errno = -err; \n\ 1406 return NULL; \n\ 1407 } \n\ 1408 return obj; \n\ 1409 } \n\ 1410 \n\ 1411 static inline int \n\ 1412 %1$s__attach(struct %1$s *obj) \n\ 1413 { \n\ 1414 return bpf_object__attach_skeleton(obj->skeleton); \n\ 1415 } \n\ 1416 \n\ 1417 static inline void \n\ 1418 %1$s__detach(struct %1$s *obj) \n\ 1419 { \n\ 1420 bpf_object__detach_skeleton(obj->skeleton); \n\ 1421 } \n\ 1422 ", 1423 obj_name 1424 ); 1425 1426 codegen("\ 1427 \n\ 1428 \n\ 1429 static inline const void *%1$s__elf_bytes(size_t *sz); \n\ 1430 \n\ 1431 static inline int \n\ 1432 %1$s__create_skeleton(struct %1$s *obj) \n\ 1433 { \n\ 1434 struct bpf_object_skeleton *s; \n\ 1435 int err; \n\ 1436 \n\ 1437 s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\ 1438 if (!s) { \n\ 1439 err = -ENOMEM; \n\ 1440 goto err; \n\ 1441 } \n\ 1442 \n\ 1443 s->sz = sizeof(*s); \n\ 1444 s->name = \"%1$s\"; \n\ 1445 s->obj = &obj->obj; \n\ 1446 ", 1447 obj_name 1448 ); 1449 1450 codegen_maps_skeleton(obj, map_cnt, true /*mmaped*/); 1451 codegen_progs_skeleton(obj, prog_cnt, true /*populate_links*/); 1452 1453 codegen("\ 1454 \n\ 1455 \n\ 1456 s->data = %1$s__elf_bytes(&s->data_sz); \n\ 1457 \n\ 1458 obj->skeleton = s; \n\ 1459 return 0; \n\ 1460 err: \n\ 1461 bpf_object__destroy_skeleton(s); \n\ 1462 return err; \n\ 1463 } \n\ 1464 \n\ 1465 static inline const void *%1$s__elf_bytes(size_t *sz) \n\ 1466 { \n\ 1467 static const char data[] __attribute__((__aligned__(8))) = \"\\\n\ 1468 ", 1469 obj_name 1470 ); 1471 1472 /* embed contents of BPF object file */ 1473 print_hex(obj_data, file_sz); 1474 1475 codegen("\ 1476 \n\ 1477 \"; \n\ 1478 \n\ 1479 *sz = sizeof(data) - 1; \n\ 1480 return (const void *)data; \n\ 1481 } \n\ 1482 \n\ 1483 #ifdef __cplusplus \n\ 1484 struct %1$s *%1$s::open(const struct bpf_object_open_opts *opts) { return %1$s__open_opts(opts); }\n\ 1485 struct %1$s *%1$s::open_and_load() { return %1$s__open_and_load(); } \n\ 1486 int %1$s::load(struct %1$s *skel) { return %1$s__load(skel); } \n\ 1487 int %1$s::attach(struct %1$s *skel) { return %1$s__attach(skel); } \n\ 1488 void %1$s::detach(struct %1$s *skel) { %1$s__detach(skel); } \n\ 1489 void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); } \n\ 1490 const void *%1$s::elf_bytes(size_t *sz) { return %1$s__elf_bytes(sz); } \n\ 1491 #endif /* __cplusplus */ \n\ 1492 \n\ 1493 ", 1494 obj_name); 1495 1496 codegen_asserts(obj, obj_name); 1497 1498 codegen("\ 1499 \n\ 1500 \n\ 1501 #endif /* %1$s */ \n\ 1502 ", 1503 header_guard); 1504 err = 0; 1505out: 1506 bpf_object__close(obj); 1507 if (obj_data) 1508 munmap(obj_data, mmap_sz); 1509 close(fd); 1510 return err; 1511} 1512 1513/* Subskeletons are like skeletons, except they don't own the bpf_object, 1514 * associated maps, links, etc. Instead, they know about the existence of 1515 * variables, maps, programs and are able to find their locations 1516 * _at runtime_ from an already loaded bpf_object. 1517 * 1518 * This allows for library-like BPF objects to have userspace counterparts 1519 * with access to their own items without having to know anything about the 1520 * final BPF object that the library was linked into. 1521 */ 1522static int do_subskeleton(int argc, char **argv) 1523{ 1524 char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SUBSKEL_H__")]; 1525 size_t i, len, file_sz, map_cnt = 0, prog_cnt = 0, mmap_sz, var_cnt = 0, var_idx = 0; 1526 DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts); 1527 char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data; 1528 struct bpf_object *obj = NULL; 1529 const char *file, *var_name; 1530 char ident[256]; 1531 int fd, err = -1, map_type_id; 1532 const struct bpf_map *map; 1533 struct bpf_program *prog; 1534 struct btf *btf; 1535 const struct btf_type *map_type, *var_type; 1536 const struct btf_var_secinfo *var; 1537 struct stat st; 1538 1539 if (!REQ_ARGS(1)) { 1540 usage(); 1541 return -1; 1542 } 1543 file = GET_ARG(); 1544 1545 while (argc) { 1546 if (!REQ_ARGS(2)) 1547 return -1; 1548 1549 if (is_prefix(*argv, "name")) { 1550 NEXT_ARG(); 1551 1552 if (obj_name[0] != '\0') { 1553 p_err("object name already specified"); 1554 return -1; 1555 } 1556 1557 strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1); 1558 obj_name[MAX_OBJ_NAME_LEN - 1] = '\0'; 1559 } else { 1560 p_err("unknown arg %s", *argv); 1561 return -1; 1562 } 1563 1564 NEXT_ARG(); 1565 } 1566 1567 if (argc) { 1568 p_err("extra unknown arguments"); 1569 return -1; 1570 } 1571 1572 if (use_loader) { 1573 p_err("cannot use loader for subskeletons"); 1574 return -1; 1575 } 1576 1577 if (stat(file, &st)) { 1578 p_err("failed to stat() %s: %s", file, strerror(errno)); 1579 return -1; 1580 } 1581 file_sz = st.st_size; 1582 mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE)); 1583 fd = open(file, O_RDONLY); 1584 if (fd < 0) { 1585 p_err("failed to open() %s: %s", file, strerror(errno)); 1586 return -1; 1587 } 1588 obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0); 1589 if (obj_data == MAP_FAILED) { 1590 obj_data = NULL; 1591 p_err("failed to mmap() %s: %s", file, strerror(errno)); 1592 goto out; 1593 } 1594 if (obj_name[0] == '\0') 1595 get_obj_name(obj_name, file); 1596 1597 /* The empty object name allows us to use bpf_map__name and produce 1598 * ELF section names out of it. (".data" instead of "obj.data") 1599 */ 1600 opts.object_name = ""; 1601 obj = bpf_object__open_mem(obj_data, file_sz, &opts); 1602 if (!obj) { 1603 char err_buf[256]; 1604 1605 libbpf_strerror(errno, err_buf, sizeof(err_buf)); 1606 p_err("failed to open BPF object file: %s", err_buf); 1607 obj = NULL; 1608 goto out; 1609 } 1610 1611 btf = bpf_object__btf(obj); 1612 if (!btf) { 1613 err = -1; 1614 p_err("need btf type information for %s", obj_name); 1615 goto out; 1616 } 1617 1618 bpf_object__for_each_program(prog, obj) { 1619 prog_cnt++; 1620 } 1621 1622 /* First, count how many variables we have to find. 1623 * We need this in advance so the subskel can allocate the right 1624 * amount of storage. 1625 */ 1626 bpf_object__for_each_map(map, obj) { 1627 if (!get_map_ident(map, ident, sizeof(ident))) 1628 continue; 1629 1630 /* Also count all maps that have a name */ 1631 map_cnt++; 1632 1633 if (!is_mmapable_map(map, ident, sizeof(ident))) 1634 continue; 1635 1636 map_type_id = bpf_map__btf_value_type_id(map); 1637 if (map_type_id <= 0) { 1638 err = map_type_id; 1639 goto out; 1640 } 1641 map_type = btf__type_by_id(btf, map_type_id); 1642 1643 var = btf_var_secinfos(map_type); 1644 len = btf_vlen(map_type); 1645 for (i = 0; i < len; i++, var++) { 1646 var_type = btf__type_by_id(btf, var->type); 1647 1648 if (btf_var(var_type)->linkage == BTF_VAR_STATIC) 1649 continue; 1650 1651 var_cnt++; 1652 } 1653 } 1654 1655 get_header_guard(header_guard, obj_name, "SUBSKEL_H"); 1656 codegen("\ 1657 \n\ 1658 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ 1659 \n\ 1660 /* THIS FILE IS AUTOGENERATED! */ \n\ 1661 #ifndef %2$s \n\ 1662 #define %2$s \n\ 1663 \n\ 1664 #include <errno.h> \n\ 1665 #include <stdlib.h> \n\ 1666 #include <bpf/libbpf.h> \n\ 1667 \n\ 1668 struct %1$s { \n\ 1669 struct bpf_object *obj; \n\ 1670 struct bpf_object_subskeleton *subskel; \n\ 1671 ", obj_name, header_guard); 1672 1673 if (map_cnt) { 1674 printf("\tstruct {\n"); 1675 bpf_object__for_each_map(map, obj) { 1676 if (!get_map_ident(map, ident, sizeof(ident))) 1677 continue; 1678 printf("\t\tstruct bpf_map *%s;\n", ident); 1679 } 1680 printf("\t} maps;\n"); 1681 } 1682 1683 err = gen_st_ops_shadow(obj_name, btf, obj); 1684 if (err) 1685 goto out; 1686 1687 if (prog_cnt) { 1688 printf("\tstruct {\n"); 1689 bpf_object__for_each_program(prog, obj) { 1690 printf("\t\tstruct bpf_program *%s;\n", 1691 bpf_program__name(prog)); 1692 } 1693 printf("\t} progs;\n"); 1694 } 1695 1696 err = codegen_subskel_datasecs(obj, obj_name); 1697 if (err) 1698 goto out; 1699 1700 /* emit code that will allocate enough storage for all symbols */ 1701 codegen("\ 1702 \n\ 1703 \n\ 1704 #ifdef __cplusplus \n\ 1705 static inline struct %1$s *open(const struct bpf_object *src);\n\ 1706 static inline void destroy(struct %1$s *skel); \n\ 1707 #endif /* __cplusplus */ \n\ 1708 }; \n\ 1709 \n\ 1710 static inline void \n\ 1711 %1$s__destroy(struct %1$s *skel) \n\ 1712 { \n\ 1713 if (!skel) \n\ 1714 return; \n\ 1715 if (skel->subskel) \n\ 1716 bpf_object__destroy_subskeleton(skel->subskel);\n\ 1717 free(skel); \n\ 1718 } \n\ 1719 \n\ 1720 static inline struct %1$s * \n\ 1721 %1$s__open(const struct bpf_object *src) \n\ 1722 { \n\ 1723 struct %1$s *obj; \n\ 1724 struct bpf_object_subskeleton *s; \n\ 1725 int err; \n\ 1726 \n\ 1727 obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\ 1728 if (!obj) { \n\ 1729 err = -ENOMEM; \n\ 1730 goto err; \n\ 1731 } \n\ 1732 s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s));\n\ 1733 if (!s) { \n\ 1734 err = -ENOMEM; \n\ 1735 goto err; \n\ 1736 } \n\ 1737 s->sz = sizeof(*s); \n\ 1738 s->obj = src; \n\ 1739 s->var_skel_sz = sizeof(*s->vars); \n\ 1740 obj->subskel = s; \n\ 1741 \n\ 1742 /* vars */ \n\ 1743 s->var_cnt = %2$d; \n\ 1744 s->vars = (struct bpf_var_skeleton *)calloc(%2$d, sizeof(*s->vars));\n\ 1745 if (!s->vars) { \n\ 1746 err = -ENOMEM; \n\ 1747 goto err; \n\ 1748 } \n\ 1749 ", 1750 obj_name, var_cnt 1751 ); 1752 1753 /* walk through each symbol and emit the runtime representation */ 1754 bpf_object__for_each_map(map, obj) { 1755 if (!is_mmapable_map(map, ident, sizeof(ident))) 1756 continue; 1757 1758 map_type_id = bpf_map__btf_value_type_id(map); 1759 if (map_type_id <= 0) 1760 /* skip over internal maps with no type*/ 1761 continue; 1762 1763 map_type = btf__type_by_id(btf, map_type_id); 1764 var = btf_var_secinfos(map_type); 1765 len = btf_vlen(map_type); 1766 for (i = 0; i < len; i++, var++) { 1767 var_type = btf__type_by_id(btf, var->type); 1768 var_name = btf__name_by_offset(btf, var_type->name_off); 1769 1770 if (btf_var(var_type)->linkage == BTF_VAR_STATIC) 1771 continue; 1772 1773 /* Note that we use the dot prefix in .data as the 1774 * field access operator i.e. maps%s becomes maps.data 1775 */ 1776 codegen("\ 1777 \n\ 1778 \n\ 1779 s->vars[%3$d].name = \"%1$s\"; \n\ 1780 s->vars[%3$d].map = &obj->maps.%2$s; \n\ 1781 s->vars[%3$d].addr = (void **) &obj->%2$s.%1$s;\n\ 1782 ", var_name, ident, var_idx); 1783 1784 var_idx++; 1785 } 1786 } 1787 1788 codegen_maps_skeleton(obj, map_cnt, false /*mmaped*/); 1789 codegen_progs_skeleton(obj, prog_cnt, false /*links*/); 1790 1791 codegen("\ 1792 \n\ 1793 \n\ 1794 err = bpf_object__open_subskeleton(s); \n\ 1795 if (err) \n\ 1796 goto err; \n\ 1797 \n\ 1798 "); 1799 1800 gen_st_ops_shadow_init(btf, obj); 1801 1802 codegen("\ 1803 \n\ 1804 return obj; \n\ 1805 err: \n\ 1806 %1$s__destroy(obj); \n\ 1807 errno = -err; \n\ 1808 return NULL; \n\ 1809 } \n\ 1810 \n\ 1811 #ifdef __cplusplus \n\ 1812 struct %1$s *%1$s::open(const struct bpf_object *src) { return %1$s__open(src); }\n\ 1813 void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); }\n\ 1814 #endif /* __cplusplus */ \n\ 1815 \n\ 1816 #endif /* %2$s */ \n\ 1817 ", 1818 obj_name, header_guard); 1819 err = 0; 1820out: 1821 bpf_object__close(obj); 1822 if (obj_data) 1823 munmap(obj_data, mmap_sz); 1824 close(fd); 1825 return err; 1826} 1827 1828static int do_object(int argc, char **argv) 1829{ 1830 struct bpf_linker *linker; 1831 const char *output_file, *file; 1832 int err = 0; 1833 1834 if (!REQ_ARGS(2)) { 1835 usage(); 1836 return -1; 1837 } 1838 1839 output_file = GET_ARG(); 1840 1841 linker = bpf_linker__new(output_file, NULL); 1842 if (!linker) { 1843 p_err("failed to create BPF linker instance"); 1844 return -1; 1845 } 1846 1847 while (argc) { 1848 file = GET_ARG(); 1849 1850 err = bpf_linker__add_file(linker, file, NULL); 1851 if (err) { 1852 p_err("failed to link '%s': %s (%d)", file, strerror(errno), errno); 1853 goto out; 1854 } 1855 } 1856 1857 err = bpf_linker__finalize(linker); 1858 if (err) { 1859 p_err("failed to finalize ELF file: %s (%d)", strerror(errno), errno); 1860 goto out; 1861 } 1862 1863 err = 0; 1864out: 1865 bpf_linker__free(linker); 1866 return err; 1867} 1868 1869static int do_help(int argc, char **argv) 1870{ 1871 if (json_output) { 1872 jsonw_null(json_wtr); 1873 return 0; 1874 } 1875 1876 fprintf(stderr, 1877 "Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n" 1878 " %1$s %2$s skeleton FILE [name OBJECT_NAME]\n" 1879 " %1$s %2$s subskeleton FILE [name OBJECT_NAME]\n" 1880 " %1$s %2$s min_core_btf INPUT OUTPUT OBJECT [OBJECT...]\n" 1881 " %1$s %2$s help\n" 1882 "\n" 1883 " " HELP_SPEC_OPTIONS " |\n" 1884 " {-L|--use-loader} }\n" 1885 "", 1886 bin_name, "gen"); 1887 1888 return 0; 1889} 1890 1891static int btf_save_raw(const struct btf *btf, const char *path) 1892{ 1893 const void *data; 1894 FILE *f = NULL; 1895 __u32 data_sz; 1896 int err = 0; 1897 1898 data = btf__raw_data(btf, &data_sz); 1899 if (!data) 1900 return -ENOMEM; 1901 1902 f = fopen(path, "wb"); 1903 if (!f) 1904 return -errno; 1905 1906 if (fwrite(data, 1, data_sz, f) != data_sz) 1907 err = -errno; 1908 1909 fclose(f); 1910 return err; 1911} 1912 1913struct btfgen_info { 1914 struct btf *src_btf; 1915 struct btf *marked_btf; /* btf structure used to mark used types */ 1916}; 1917 1918static size_t btfgen_hash_fn(long key, void *ctx) 1919{ 1920 return key; 1921} 1922 1923static bool btfgen_equal_fn(long k1, long k2, void *ctx) 1924{ 1925 return k1 == k2; 1926} 1927 1928static void btfgen_free_info(struct btfgen_info *info) 1929{ 1930 if (!info) 1931 return; 1932 1933 btf__free(info->src_btf); 1934 btf__free(info->marked_btf); 1935 1936 free(info); 1937} 1938 1939static struct btfgen_info * 1940btfgen_new_info(const char *targ_btf_path) 1941{ 1942 struct btfgen_info *info; 1943 int err; 1944 1945 info = calloc(1, sizeof(*info)); 1946 if (!info) 1947 return NULL; 1948 1949 info->src_btf = btf__parse(targ_btf_path, NULL); 1950 if (!info->src_btf) { 1951 err = -errno; 1952 p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno)); 1953 goto err_out; 1954 } 1955 1956 info->marked_btf = btf__parse(targ_btf_path, NULL); 1957 if (!info->marked_btf) { 1958 err = -errno; 1959 p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno)); 1960 goto err_out; 1961 } 1962 1963 return info; 1964 1965err_out: 1966 btfgen_free_info(info); 1967 errno = -err; 1968 return NULL; 1969} 1970 1971#define MARKED UINT32_MAX 1972 1973static void btfgen_mark_member(struct btfgen_info *info, int type_id, int idx) 1974{ 1975 const struct btf_type *t = btf__type_by_id(info->marked_btf, type_id); 1976 struct btf_member *m = btf_members(t) + idx; 1977 1978 m->name_off = MARKED; 1979} 1980 1981static int 1982btfgen_mark_type(struct btfgen_info *info, unsigned int type_id, bool follow_pointers) 1983{ 1984 const struct btf_type *btf_type = btf__type_by_id(info->src_btf, type_id); 1985 struct btf_type *cloned_type; 1986 struct btf_param *param; 1987 struct btf_array *array; 1988 int err, i; 1989 1990 if (type_id == 0) 1991 return 0; 1992 1993 /* mark type on cloned BTF as used */ 1994 cloned_type = (struct btf_type *) btf__type_by_id(info->marked_btf, type_id); 1995 cloned_type->name_off = MARKED; 1996 1997 /* recursively mark other types needed by it */ 1998 switch (btf_kind(btf_type)) { 1999 case BTF_KIND_UNKN: 2000 case BTF_KIND_INT: 2001 case BTF_KIND_FLOAT: 2002 case BTF_KIND_ENUM: 2003 case BTF_KIND_ENUM64: 2004 case BTF_KIND_STRUCT: 2005 case BTF_KIND_UNION: 2006 break; 2007 case BTF_KIND_PTR: 2008 if (follow_pointers) { 2009 err = btfgen_mark_type(info, btf_type->type, follow_pointers); 2010 if (err) 2011 return err; 2012 } 2013 break; 2014 case BTF_KIND_CONST: 2015 case BTF_KIND_RESTRICT: 2016 case BTF_KIND_VOLATILE: 2017 case BTF_KIND_TYPEDEF: 2018 err = btfgen_mark_type(info, btf_type->type, follow_pointers); 2019 if (err) 2020 return err; 2021 break; 2022 case BTF_KIND_ARRAY: 2023 array = btf_array(btf_type); 2024 2025 /* mark array type */ 2026 err = btfgen_mark_type(info, array->type, follow_pointers); 2027 /* mark array's index type */ 2028 err = err ? : btfgen_mark_type(info, array->index_type, follow_pointers); 2029 if (err) 2030 return err; 2031 break; 2032 case BTF_KIND_FUNC_PROTO: 2033 /* mark ret type */ 2034 err = btfgen_mark_type(info, btf_type->type, follow_pointers); 2035 if (err) 2036 return err; 2037 2038 /* mark parameters types */ 2039 param = btf_params(btf_type); 2040 for (i = 0; i < btf_vlen(btf_type); i++) { 2041 err = btfgen_mark_type(info, param->type, follow_pointers); 2042 if (err) 2043 return err; 2044 param++; 2045 } 2046 break; 2047 /* tells if some other type needs to be handled */ 2048 default: 2049 p_err("unsupported kind: %s (%d)", btf_kind_str(btf_type), type_id); 2050 return -EINVAL; 2051 } 2052 2053 return 0; 2054} 2055 2056static int btfgen_record_field_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec) 2057{ 2058 struct btf *btf = info->src_btf; 2059 const struct btf_type *btf_type; 2060 struct btf_member *btf_member; 2061 struct btf_array *array; 2062 unsigned int type_id = targ_spec->root_type_id; 2063 int idx, err; 2064 2065 /* mark root type */ 2066 btf_type = btf__type_by_id(btf, type_id); 2067 err = btfgen_mark_type(info, type_id, false); 2068 if (err) 2069 return err; 2070 2071 /* mark types for complex types (arrays, unions, structures) */ 2072 for (int i = 1; i < targ_spec->raw_len; i++) { 2073 /* skip typedefs and mods */ 2074 while (btf_is_mod(btf_type) || btf_is_typedef(btf_type)) { 2075 type_id = btf_type->type; 2076 btf_type = btf__type_by_id(btf, type_id); 2077 } 2078 2079 switch (btf_kind(btf_type)) { 2080 case BTF_KIND_STRUCT: 2081 case BTF_KIND_UNION: 2082 idx = targ_spec->raw_spec[i]; 2083 btf_member = btf_members(btf_type) + idx; 2084 2085 /* mark member */ 2086 btfgen_mark_member(info, type_id, idx); 2087 2088 /* mark member's type */ 2089 type_id = btf_member->type; 2090 btf_type = btf__type_by_id(btf, type_id); 2091 err = btfgen_mark_type(info, type_id, false); 2092 if (err) 2093 return err; 2094 break; 2095 case BTF_KIND_ARRAY: 2096 array = btf_array(btf_type); 2097 type_id = array->type; 2098 btf_type = btf__type_by_id(btf, type_id); 2099 break; 2100 default: 2101 p_err("unsupported kind: %s (%d)", 2102 btf_kind_str(btf_type), btf_type->type); 2103 return -EINVAL; 2104 } 2105 } 2106 2107 return 0; 2108} 2109 2110/* Mark types, members, and member types. Compared to btfgen_record_field_relo, 2111 * this function does not rely on the target spec for inferring members, but 2112 * uses the associated BTF. 2113 * 2114 * The `behind_ptr` argument is used to stop marking of composite types reached 2115 * through a pointer. This way, we can keep BTF size in check while providing 2116 * reasonable match semantics. 2117 */ 2118static int btfgen_mark_type_match(struct btfgen_info *info, __u32 type_id, bool behind_ptr) 2119{ 2120 const struct btf_type *btf_type; 2121 struct btf *btf = info->src_btf; 2122 struct btf_type *cloned_type; 2123 int i, err; 2124 2125 if (type_id == 0) 2126 return 0; 2127 2128 btf_type = btf__type_by_id(btf, type_id); 2129 /* mark type on cloned BTF as used */ 2130 cloned_type = (struct btf_type *)btf__type_by_id(info->marked_btf, type_id); 2131 cloned_type->name_off = MARKED; 2132 2133 switch (btf_kind(btf_type)) { 2134 case BTF_KIND_UNKN: 2135 case BTF_KIND_INT: 2136 case BTF_KIND_FLOAT: 2137 case BTF_KIND_ENUM: 2138 case BTF_KIND_ENUM64: 2139 break; 2140 case BTF_KIND_STRUCT: 2141 case BTF_KIND_UNION: { 2142 struct btf_member *m = btf_members(btf_type); 2143 __u16 vlen = btf_vlen(btf_type); 2144 2145 if (behind_ptr) 2146 break; 2147 2148 for (i = 0; i < vlen; i++, m++) { 2149 /* mark member */ 2150 btfgen_mark_member(info, type_id, i); 2151 2152 /* mark member's type */ 2153 err = btfgen_mark_type_match(info, m->type, false); 2154 if (err) 2155 return err; 2156 } 2157 break; 2158 } 2159 case BTF_KIND_CONST: 2160 case BTF_KIND_FWD: 2161 case BTF_KIND_RESTRICT: 2162 case BTF_KIND_TYPEDEF: 2163 case BTF_KIND_VOLATILE: 2164 return btfgen_mark_type_match(info, btf_type->type, behind_ptr); 2165 case BTF_KIND_PTR: 2166 return btfgen_mark_type_match(info, btf_type->type, true); 2167 case BTF_KIND_ARRAY: { 2168 struct btf_array *array; 2169 2170 array = btf_array(btf_type); 2171 /* mark array type */ 2172 err = btfgen_mark_type_match(info, array->type, false); 2173 /* mark array's index type */ 2174 err = err ? : btfgen_mark_type_match(info, array->index_type, false); 2175 if (err) 2176 return err; 2177 break; 2178 } 2179 case BTF_KIND_FUNC_PROTO: { 2180 __u16 vlen = btf_vlen(btf_type); 2181 struct btf_param *param; 2182 2183 /* mark ret type */ 2184 err = btfgen_mark_type_match(info, btf_type->type, false); 2185 if (err) 2186 return err; 2187 2188 /* mark parameters types */ 2189 param = btf_params(btf_type); 2190 for (i = 0; i < vlen; i++) { 2191 err = btfgen_mark_type_match(info, param->type, false); 2192 if (err) 2193 return err; 2194 param++; 2195 } 2196 break; 2197 } 2198 /* tells if some other type needs to be handled */ 2199 default: 2200 p_err("unsupported kind: %s (%d)", btf_kind_str(btf_type), type_id); 2201 return -EINVAL; 2202 } 2203 2204 return 0; 2205} 2206 2207/* Mark types, members, and member types. Compared to btfgen_record_field_relo, 2208 * this function does not rely on the target spec for inferring members, but 2209 * uses the associated BTF. 2210 */ 2211static int btfgen_record_type_match_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec) 2212{ 2213 return btfgen_mark_type_match(info, targ_spec->root_type_id, false); 2214} 2215 2216static int btfgen_record_type_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec) 2217{ 2218 return btfgen_mark_type(info, targ_spec->root_type_id, true); 2219} 2220 2221static int btfgen_record_enumval_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec) 2222{ 2223 return btfgen_mark_type(info, targ_spec->root_type_id, false); 2224} 2225 2226static int btfgen_record_reloc(struct btfgen_info *info, struct bpf_core_spec *res) 2227{ 2228 switch (res->relo_kind) { 2229 case BPF_CORE_FIELD_BYTE_OFFSET: 2230 case BPF_CORE_FIELD_BYTE_SIZE: 2231 case BPF_CORE_FIELD_EXISTS: 2232 case BPF_CORE_FIELD_SIGNED: 2233 case BPF_CORE_FIELD_LSHIFT_U64: 2234 case BPF_CORE_FIELD_RSHIFT_U64: 2235 return btfgen_record_field_relo(info, res); 2236 case BPF_CORE_TYPE_ID_LOCAL: /* BPF_CORE_TYPE_ID_LOCAL doesn't require kernel BTF */ 2237 return 0; 2238 case BPF_CORE_TYPE_ID_TARGET: 2239 case BPF_CORE_TYPE_EXISTS: 2240 case BPF_CORE_TYPE_SIZE: 2241 return btfgen_record_type_relo(info, res); 2242 case BPF_CORE_TYPE_MATCHES: 2243 return btfgen_record_type_match_relo(info, res); 2244 case BPF_CORE_ENUMVAL_EXISTS: 2245 case BPF_CORE_ENUMVAL_VALUE: 2246 return btfgen_record_enumval_relo(info, res); 2247 default: 2248 return -EINVAL; 2249 } 2250} 2251 2252static struct bpf_core_cand_list * 2253btfgen_find_cands(const struct btf *local_btf, const struct btf *targ_btf, __u32 local_id) 2254{ 2255 const struct btf_type *local_type; 2256 struct bpf_core_cand_list *cands = NULL; 2257 struct bpf_core_cand local_cand = {}; 2258 size_t local_essent_len; 2259 const char *local_name; 2260 int err; 2261 2262 local_cand.btf = local_btf; 2263 local_cand.id = local_id; 2264 2265 local_type = btf__type_by_id(local_btf, local_id); 2266 if (!local_type) { 2267 err = -EINVAL; 2268 goto err_out; 2269 } 2270 2271 local_name = btf__name_by_offset(local_btf, local_type->name_off); 2272 if (!local_name) { 2273 err = -EINVAL; 2274 goto err_out; 2275 } 2276 local_essent_len = bpf_core_essential_name_len(local_name); 2277 2278 cands = calloc(1, sizeof(*cands)); 2279 if (!cands) 2280 return NULL; 2281 2282 err = bpf_core_add_cands(&local_cand, local_essent_len, targ_btf, "vmlinux", 1, cands); 2283 if (err) 2284 goto err_out; 2285 2286 return cands; 2287 2288err_out: 2289 bpf_core_free_cands(cands); 2290 errno = -err; 2291 return NULL; 2292} 2293 2294/* Record relocation information for a single BPF object */ 2295static int btfgen_record_obj(struct btfgen_info *info, const char *obj_path) 2296{ 2297 const struct btf_ext_info_sec *sec; 2298 const struct bpf_core_relo *relo; 2299 const struct btf_ext_info *seg; 2300 struct hashmap_entry *entry; 2301 struct hashmap *cand_cache = NULL; 2302 struct btf_ext *btf_ext = NULL; 2303 unsigned int relo_idx; 2304 struct btf *btf = NULL; 2305 size_t i; 2306 int err; 2307 2308 btf = btf__parse(obj_path, &btf_ext); 2309 if (!btf) { 2310 err = -errno; 2311 p_err("failed to parse BPF object '%s': %s", obj_path, strerror(errno)); 2312 return err; 2313 } 2314 2315 if (!btf_ext) { 2316 p_err("failed to parse BPF object '%s': section %s not found", 2317 obj_path, BTF_EXT_ELF_SEC); 2318 err = -EINVAL; 2319 goto out; 2320 } 2321 2322 if (btf_ext->core_relo_info.len == 0) { 2323 err = 0; 2324 goto out; 2325 } 2326 2327 cand_cache = hashmap__new(btfgen_hash_fn, btfgen_equal_fn, NULL); 2328 if (IS_ERR(cand_cache)) { 2329 err = PTR_ERR(cand_cache); 2330 goto out; 2331 } 2332 2333 seg = &btf_ext->core_relo_info; 2334 for_each_btf_ext_sec(seg, sec) { 2335 for_each_btf_ext_rec(seg, sec, relo_idx, relo) { 2336 struct bpf_core_spec specs_scratch[3] = {}; 2337 struct bpf_core_relo_res targ_res = {}; 2338 struct bpf_core_cand_list *cands = NULL; 2339 const char *sec_name = btf__name_by_offset(btf, sec->sec_name_off); 2340 2341 if (relo->kind != BPF_CORE_TYPE_ID_LOCAL && 2342 !hashmap__find(cand_cache, relo->type_id, &cands)) { 2343 cands = btfgen_find_cands(btf, info->src_btf, relo->type_id); 2344 if (!cands) { 2345 err = -errno; 2346 goto out; 2347 } 2348 2349 err = hashmap__set(cand_cache, relo->type_id, cands, 2350 NULL, NULL); 2351 if (err) 2352 goto out; 2353 } 2354 2355 err = bpf_core_calc_relo_insn(sec_name, relo, relo_idx, btf, cands, 2356 specs_scratch, &targ_res); 2357 if (err) 2358 goto out; 2359 2360 /* specs_scratch[2] is the target spec */ 2361 err = btfgen_record_reloc(info, &specs_scratch[2]); 2362 if (err) 2363 goto out; 2364 } 2365 } 2366 2367out: 2368 btf__free(btf); 2369 btf_ext__free(btf_ext); 2370 2371 if (!IS_ERR_OR_NULL(cand_cache)) { 2372 hashmap__for_each_entry(cand_cache, entry, i) { 2373 bpf_core_free_cands(entry->pvalue); 2374 } 2375 hashmap__free(cand_cache); 2376 } 2377 2378 return err; 2379} 2380 2381static int btfgen_remap_id(__u32 *type_id, void *ctx) 2382{ 2383 unsigned int *ids = ctx; 2384 2385 *type_id = ids[*type_id]; 2386 2387 return 0; 2388} 2389 2390/* Generate BTF from relocation information previously recorded */ 2391static struct btf *btfgen_get_btf(struct btfgen_info *info) 2392{ 2393 struct btf *btf_new = NULL; 2394 unsigned int *ids = NULL; 2395 unsigned int i, n = btf__type_cnt(info->marked_btf); 2396 int err = 0; 2397 2398 btf_new = btf__new_empty(); 2399 if (!btf_new) { 2400 err = -errno; 2401 goto err_out; 2402 } 2403 2404 ids = calloc(n, sizeof(*ids)); 2405 if (!ids) { 2406 err = -errno; 2407 goto err_out; 2408 } 2409 2410 /* first pass: add all marked types to btf_new and add their new ids to the ids map */ 2411 for (i = 1; i < n; i++) { 2412 const struct btf_type *cloned_type, *type; 2413 const char *name; 2414 int new_id; 2415 2416 cloned_type = btf__type_by_id(info->marked_btf, i); 2417 2418 if (cloned_type->name_off != MARKED) 2419 continue; 2420 2421 type = btf__type_by_id(info->src_btf, i); 2422 2423 /* add members for struct and union */ 2424 if (btf_is_composite(type)) { 2425 struct btf_member *cloned_m, *m; 2426 unsigned short vlen; 2427 int idx_src; 2428 2429 name = btf__str_by_offset(info->src_btf, type->name_off); 2430 2431 if (btf_is_struct(type)) 2432 err = btf__add_struct(btf_new, name, type->size); 2433 else 2434 err = btf__add_union(btf_new, name, type->size); 2435 2436 if (err < 0) 2437 goto err_out; 2438 new_id = err; 2439 2440 cloned_m = btf_members(cloned_type); 2441 m = btf_members(type); 2442 vlen = btf_vlen(cloned_type); 2443 for (idx_src = 0; idx_src < vlen; idx_src++, cloned_m++, m++) { 2444 /* add only members that are marked as used */ 2445 if (cloned_m->name_off != MARKED) 2446 continue; 2447 2448 name = btf__str_by_offset(info->src_btf, m->name_off); 2449 err = btf__add_field(btf_new, name, m->type, 2450 btf_member_bit_offset(cloned_type, idx_src), 2451 btf_member_bitfield_size(cloned_type, idx_src)); 2452 if (err < 0) 2453 goto err_out; 2454 } 2455 } else { 2456 err = btf__add_type(btf_new, info->src_btf, type); 2457 if (err < 0) 2458 goto err_out; 2459 new_id = err; 2460 } 2461 2462 /* add ID mapping */ 2463 ids[i] = new_id; 2464 } 2465 2466 /* second pass: fix up type ids */ 2467 for (i = 1; i < btf__type_cnt(btf_new); i++) { 2468 struct btf_type *btf_type = (struct btf_type *) btf__type_by_id(btf_new, i); 2469 2470 err = btf_type_visit_type_ids(btf_type, btfgen_remap_id, ids); 2471 if (err) 2472 goto err_out; 2473 } 2474 2475 free(ids); 2476 return btf_new; 2477 2478err_out: 2479 btf__free(btf_new); 2480 free(ids); 2481 errno = -err; 2482 return NULL; 2483} 2484 2485/* Create minimized BTF file for a set of BPF objects. 2486 * 2487 * The BTFGen algorithm is divided in two main parts: (1) collect the 2488 * BTF types that are involved in relocations and (2) generate the BTF 2489 * object using the collected types. 2490 * 2491 * In order to collect the types involved in the relocations, we parse 2492 * the BTF and BTF.ext sections of the BPF objects and use 2493 * bpf_core_calc_relo_insn() to get the target specification, this 2494 * indicates how the types and fields are used in a relocation. 2495 * 2496 * Types are recorded in different ways according to the kind of the 2497 * relocation. For field-based relocations only the members that are 2498 * actually used are saved in order to reduce the size of the generated 2499 * BTF file. For type-based relocations empty struct / unions are 2500 * generated and for enum-based relocations the whole type is saved. 2501 * 2502 * The second part of the algorithm generates the BTF object. It creates 2503 * an empty BTF object and fills it with the types recorded in the 2504 * previous step. This function takes care of only adding the structure 2505 * and union members that were marked as used and it also fixes up the 2506 * type IDs on the generated BTF object. 2507 */ 2508static int minimize_btf(const char *src_btf, const char *dst_btf, const char *objspaths[]) 2509{ 2510 struct btfgen_info *info; 2511 struct btf *btf_new = NULL; 2512 int err, i; 2513 2514 info = btfgen_new_info(src_btf); 2515 if (!info) { 2516 err = -errno; 2517 p_err("failed to allocate info structure: %s", strerror(errno)); 2518 goto out; 2519 } 2520 2521 for (i = 0; objspaths[i] != NULL; i++) { 2522 err = btfgen_record_obj(info, objspaths[i]); 2523 if (err) { 2524 p_err("error recording relocations for %s: %s", objspaths[i], 2525 strerror(errno)); 2526 goto out; 2527 } 2528 } 2529 2530 btf_new = btfgen_get_btf(info); 2531 if (!btf_new) { 2532 err = -errno; 2533 p_err("error generating BTF: %s", strerror(errno)); 2534 goto out; 2535 } 2536 2537 err = btf_save_raw(btf_new, dst_btf); 2538 if (err) { 2539 p_err("error saving btf file: %s", strerror(errno)); 2540 goto out; 2541 } 2542 2543out: 2544 btf__free(btf_new); 2545 btfgen_free_info(info); 2546 2547 return err; 2548} 2549 2550static int do_min_core_btf(int argc, char **argv) 2551{ 2552 const char *input, *output, **objs; 2553 int i, err; 2554 2555 if (!REQ_ARGS(3)) { 2556 usage(); 2557 return -1; 2558 } 2559 2560 input = GET_ARG(); 2561 output = GET_ARG(); 2562 2563 objs = (const char **) calloc(argc + 1, sizeof(*objs)); 2564 if (!objs) { 2565 p_err("failed to allocate array for object names"); 2566 return -ENOMEM; 2567 } 2568 2569 i = 0; 2570 while (argc) 2571 objs[i++] = GET_ARG(); 2572 2573 err = minimize_btf(input, output, objs); 2574 free(objs); 2575 return err; 2576} 2577 2578static const struct cmd cmds[] = { 2579 { "object", do_object }, 2580 { "skeleton", do_skeleton }, 2581 { "subskeleton", do_subskeleton }, 2582 { "min_core_btf", do_min_core_btf}, 2583 { "help", do_help }, 2584 { 0 } 2585}; 2586 2587int do_gen(int argc, char **argv) 2588{ 2589 return cmd_select(cmds, argc, argv, do_help); 2590} 2591