1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* Copyright (C) 2019 Facebook */ 3 4 #include <errno.h> 5 #include <fcntl.h> 6 #include <linux/err.h> 7 #include <stdbool.h> 8 #include <stdio.h> 9 #include <string.h> 10 #include <unistd.h> 11 #include <bpf/bpf.h> 12 #include <bpf/btf.h> 13 #include <bpf/libbpf.h> 14 #include <linux/btf.h> 15 #include <linux/hashtable.h> 16 #include <sys/types.h> 17 #include <sys/stat.h> 18 19 #include "json_writer.h" 20 #include "main.h" 21 22 static const char * const btf_kind_str[NR_BTF_KINDS] = { 23 [BTF_KIND_UNKN] = "UNKNOWN", 24 [BTF_KIND_INT] = "INT", 25 [BTF_KIND_PTR] = "PTR", 26 [BTF_KIND_ARRAY] = "ARRAY", 27 [BTF_KIND_STRUCT] = "STRUCT", 28 [BTF_KIND_UNION] = "UNION", 29 [BTF_KIND_ENUM] = "ENUM", 30 [BTF_KIND_FWD] = "FWD", 31 [BTF_KIND_TYPEDEF] = "TYPEDEF", 32 [BTF_KIND_VOLATILE] = "VOLATILE", 33 [BTF_KIND_CONST] = "CONST", 34 [BTF_KIND_RESTRICT] = "RESTRICT", 35 [BTF_KIND_FUNC] = "FUNC", 36 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", 37 [BTF_KIND_VAR] = "VAR", 38 [BTF_KIND_DATASEC] = "DATASEC", 39 }; 40 41 struct btf_attach_table { 42 DECLARE_HASHTABLE(table, 16); 43 }; 44 45 struct btf_attach_point { 46 __u32 obj_id; 47 __u32 btf_id; 48 struct hlist_node hash; 49 }; 50 51 static const char *btf_int_enc_str(__u8 encoding) 52 { 53 switch (encoding) { 54 case 0: 55 return "(none)"; 56 case BTF_INT_SIGNED: 57 return "SIGNED"; 58 case BTF_INT_CHAR: 59 return "CHAR"; 60 case BTF_INT_BOOL: 61 return "BOOL"; 62 default: 63 return "UNKN"; 64 } 65 } 66 67 static const char *btf_var_linkage_str(__u32 linkage) 68 { 69 switch (linkage) { 70 case BTF_VAR_STATIC: 71 return "static"; 72 case BTF_VAR_GLOBAL_ALLOCATED: 73 return "global-alloc"; 74 default: 75 return "(unknown)"; 76 } 77 } 78 79 static const char *btf_func_linkage_str(const struct btf_type *t) 80 { 81 switch (btf_vlen(t)) { 82 case BTF_FUNC_STATIC: 83 return "static"; 84 case BTF_FUNC_GLOBAL: 85 return "global"; 86 case BTF_FUNC_EXTERN: 87 return "extern"; 88 default: 89 return "(unknown)"; 90 } 91 } 92 93 static const char *btf_str(const struct btf *btf, __u32 off) 94 { 95 if (!off) 96 return "(anon)"; 97 return btf__name_by_offset(btf, off) ? : "(invalid)"; 98 } 99 100 static int dump_btf_type(const struct btf *btf, __u32 id, 101 const struct btf_type *t) 102 { 103 json_writer_t *w = json_wtr; 104 int kind, safe_kind; 105 106 kind = BTF_INFO_KIND(t->info); 107 safe_kind = kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; 108 109 if (json_output) { 110 jsonw_start_object(w); 111 jsonw_uint_field(w, "id", id); 112 jsonw_string_field(w, "kind", btf_kind_str[safe_kind]); 113 jsonw_string_field(w, "name", btf_str(btf, t->name_off)); 114 } else { 115 printf("[%u] %s '%s'", id, btf_kind_str[safe_kind], 116 btf_str(btf, t->name_off)); 117 } 118 119 switch (BTF_INFO_KIND(t->info)) { 120 case BTF_KIND_INT: { 121 __u32 v = *(__u32 *)(t + 1); 122 const char *enc; 123 124 enc = btf_int_enc_str(BTF_INT_ENCODING(v)); 125 126 if (json_output) { 127 jsonw_uint_field(w, "size", t->size); 128 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v)); 129 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v)); 130 jsonw_string_field(w, "encoding", enc); 131 } else { 132 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s", 133 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v), 134 enc); 135 } 136 break; 137 } 138 case BTF_KIND_PTR: 139 case BTF_KIND_CONST: 140 case BTF_KIND_VOLATILE: 141 case BTF_KIND_RESTRICT: 142 case BTF_KIND_TYPEDEF: 143 if (json_output) 144 jsonw_uint_field(w, "type_id", t->type); 145 else 146 printf(" type_id=%u", t->type); 147 break; 148 case BTF_KIND_ARRAY: { 149 const struct btf_array *arr = (const void *)(t + 1); 150 151 if (json_output) { 152 jsonw_uint_field(w, "type_id", arr->type); 153 jsonw_uint_field(w, "index_type_id", arr->index_type); 154 jsonw_uint_field(w, "nr_elems", arr->nelems); 155 } else { 156 printf(" type_id=%u index_type_id=%u nr_elems=%u", 157 arr->type, arr->index_type, arr->nelems); 158 } 159 break; 160 } 161 case BTF_KIND_STRUCT: 162 case BTF_KIND_UNION: { 163 const struct btf_member *m = (const void *)(t + 1); 164 __u16 vlen = BTF_INFO_VLEN(t->info); 165 int i; 166 167 if (json_output) { 168 jsonw_uint_field(w, "size", t->size); 169 jsonw_uint_field(w, "vlen", vlen); 170 jsonw_name(w, "members"); 171 jsonw_start_array(w); 172 } else { 173 printf(" size=%u vlen=%u", t->size, vlen); 174 } 175 for (i = 0; i < vlen; i++, m++) { 176 const char *name = btf_str(btf, m->name_off); 177 __u32 bit_off, bit_sz; 178 179 if (BTF_INFO_KFLAG(t->info)) { 180 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset); 181 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset); 182 } else { 183 bit_off = m->offset; 184 bit_sz = 0; 185 } 186 187 if (json_output) { 188 jsonw_start_object(w); 189 jsonw_string_field(w, "name", name); 190 jsonw_uint_field(w, "type_id", m->type); 191 jsonw_uint_field(w, "bits_offset", bit_off); 192 if (bit_sz) { 193 jsonw_uint_field(w, "bitfield_size", 194 bit_sz); 195 } 196 jsonw_end_object(w); 197 } else { 198 printf("\n\t'%s' type_id=%u bits_offset=%u", 199 name, m->type, bit_off); 200 if (bit_sz) 201 printf(" bitfield_size=%u", bit_sz); 202 } 203 } 204 if (json_output) 205 jsonw_end_array(w); 206 break; 207 } 208 case BTF_KIND_ENUM: { 209 const struct btf_enum *v = (const void *)(t + 1); 210 __u16 vlen = BTF_INFO_VLEN(t->info); 211 int i; 212 213 if (json_output) { 214 jsonw_uint_field(w, "size", t->size); 215 jsonw_uint_field(w, "vlen", vlen); 216 jsonw_name(w, "values"); 217 jsonw_start_array(w); 218 } else { 219 printf(" size=%u vlen=%u", t->size, vlen); 220 } 221 for (i = 0; i < vlen; i++, v++) { 222 const char *name = btf_str(btf, v->name_off); 223 224 if (json_output) { 225 jsonw_start_object(w); 226 jsonw_string_field(w, "name", name); 227 jsonw_uint_field(w, "val", v->val); 228 jsonw_end_object(w); 229 } else { 230 printf("\n\t'%s' val=%u", name, v->val); 231 } 232 } 233 if (json_output) 234 jsonw_end_array(w); 235 break; 236 } 237 case BTF_KIND_FWD: { 238 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union" 239 : "struct"; 240 241 if (json_output) 242 jsonw_string_field(w, "fwd_kind", fwd_kind); 243 else 244 printf(" fwd_kind=%s", fwd_kind); 245 break; 246 } 247 case BTF_KIND_FUNC: { 248 const char *linkage = btf_func_linkage_str(t); 249 250 if (json_output) { 251 jsonw_uint_field(w, "type_id", t->type); 252 jsonw_string_field(w, "linkage", linkage); 253 } else { 254 printf(" type_id=%u linkage=%s", t->type, linkage); 255 } 256 break; 257 } 258 case BTF_KIND_FUNC_PROTO: { 259 const struct btf_param *p = (const void *)(t + 1); 260 __u16 vlen = BTF_INFO_VLEN(t->info); 261 int i; 262 263 if (json_output) { 264 jsonw_uint_field(w, "ret_type_id", t->type); 265 jsonw_uint_field(w, "vlen", vlen); 266 jsonw_name(w, "params"); 267 jsonw_start_array(w); 268 } else { 269 printf(" ret_type_id=%u vlen=%u", t->type, vlen); 270 } 271 for (i = 0; i < vlen; i++, p++) { 272 const char *name = btf_str(btf, p->name_off); 273 274 if (json_output) { 275 jsonw_start_object(w); 276 jsonw_string_field(w, "name", name); 277 jsonw_uint_field(w, "type_id", p->type); 278 jsonw_end_object(w); 279 } else { 280 printf("\n\t'%s' type_id=%u", name, p->type); 281 } 282 } 283 if (json_output) 284 jsonw_end_array(w); 285 break; 286 } 287 case BTF_KIND_VAR: { 288 const struct btf_var *v = (const void *)(t + 1); 289 const char *linkage; 290 291 linkage = btf_var_linkage_str(v->linkage); 292 293 if (json_output) { 294 jsonw_uint_field(w, "type_id", t->type); 295 jsonw_string_field(w, "linkage", linkage); 296 } else { 297 printf(" type_id=%u, linkage=%s", t->type, linkage); 298 } 299 break; 300 } 301 case BTF_KIND_DATASEC: { 302 const struct btf_var_secinfo *v = (const void *)(t+1); 303 __u16 vlen = BTF_INFO_VLEN(t->info); 304 int i; 305 306 if (json_output) { 307 jsonw_uint_field(w, "size", t->size); 308 jsonw_uint_field(w, "vlen", vlen); 309 jsonw_name(w, "vars"); 310 jsonw_start_array(w); 311 } else { 312 printf(" size=%u vlen=%u", t->size, vlen); 313 } 314 for (i = 0; i < vlen; i++, v++) { 315 if (json_output) { 316 jsonw_start_object(w); 317 jsonw_uint_field(w, "type_id", v->type); 318 jsonw_uint_field(w, "offset", v->offset); 319 jsonw_uint_field(w, "size", v->size); 320 jsonw_end_object(w); 321 } else { 322 printf("\n\ttype_id=%u offset=%u size=%u", 323 v->type, v->offset, v->size); 324 } 325 } 326 if (json_output) 327 jsonw_end_array(w); 328 break; 329 } 330 default: 331 break; 332 } 333 334 if (json_output) 335 jsonw_end_object(json_wtr); 336 else 337 printf("\n"); 338 339 return 0; 340 } 341 342 static int dump_btf_raw(const struct btf *btf, 343 __u32 *root_type_ids, int root_type_cnt) 344 { 345 const struct btf_type *t; 346 int i; 347 348 if (json_output) { 349 jsonw_start_object(json_wtr); 350 jsonw_name(json_wtr, "types"); 351 jsonw_start_array(json_wtr); 352 } 353 354 if (root_type_cnt) { 355 for (i = 0; i < root_type_cnt; i++) { 356 t = btf__type_by_id(btf, root_type_ids[i]); 357 dump_btf_type(btf, root_type_ids[i], t); 358 } 359 } else { 360 int cnt = btf__get_nr_types(btf); 361 362 for (i = 1; i <= cnt; i++) { 363 t = btf__type_by_id(btf, i); 364 dump_btf_type(btf, i, t); 365 } 366 } 367 368 if (json_output) { 369 jsonw_end_array(json_wtr); 370 jsonw_end_object(json_wtr); 371 } 372 return 0; 373 } 374 375 static void __printf(2, 0) btf_dump_printf(void *ctx, 376 const char *fmt, va_list args) 377 { 378 vfprintf(stdout, fmt, args); 379 } 380 381 static int dump_btf_c(const struct btf *btf, 382 __u32 *root_type_ids, int root_type_cnt) 383 { 384 struct btf_dump *d; 385 int err = 0, i; 386 387 d = btf_dump__new(btf, NULL, NULL, btf_dump_printf); 388 if (IS_ERR(d)) 389 return PTR_ERR(d); 390 391 printf("#ifndef __VMLINUX_H__\n"); 392 printf("#define __VMLINUX_H__\n"); 393 printf("\n"); 394 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 395 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); 396 printf("#endif\n\n"); 397 398 if (root_type_cnt) { 399 for (i = 0; i < root_type_cnt; i++) { 400 err = btf_dump__dump_type(d, root_type_ids[i]); 401 if (err) 402 goto done; 403 } 404 } else { 405 int cnt = btf__get_nr_types(btf); 406 407 for (i = 1; i <= cnt; i++) { 408 err = btf_dump__dump_type(d, i); 409 if (err) 410 goto done; 411 } 412 } 413 414 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 415 printf("#pragma clang attribute pop\n"); 416 printf("#endif\n"); 417 printf("\n"); 418 printf("#endif /* __VMLINUX_H__ */\n"); 419 420 done: 421 btf_dump__free(d); 422 return err; 423 } 424 425 static struct btf *btf__parse_raw(const char *file) 426 { 427 struct btf *btf; 428 struct stat st; 429 __u8 *buf; 430 FILE *f; 431 432 if (stat(file, &st)) 433 return NULL; 434 435 f = fopen(file, "rb"); 436 if (!f) 437 return NULL; 438 439 buf = malloc(st.st_size); 440 if (!buf) { 441 btf = ERR_PTR(-ENOMEM); 442 goto exit_close; 443 } 444 445 if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) { 446 btf = ERR_PTR(-EINVAL); 447 goto exit_free; 448 } 449 450 btf = btf__new(buf, st.st_size); 451 452 exit_free: 453 free(buf); 454 exit_close: 455 fclose(f); 456 return btf; 457 } 458 459 static bool is_btf_raw(const char *file) 460 { 461 __u16 magic = 0; 462 int fd, nb_read; 463 464 fd = open(file, O_RDONLY); 465 if (fd < 0) 466 return false; 467 468 nb_read = read(fd, &magic, sizeof(magic)); 469 close(fd); 470 return nb_read == sizeof(magic) && magic == BTF_MAGIC; 471 } 472 473 static int do_dump(int argc, char **argv) 474 { 475 struct btf *btf = NULL; 476 __u32 root_type_ids[2]; 477 int root_type_cnt = 0; 478 bool dump_c = false; 479 __u32 btf_id = -1; 480 const char *src; 481 int fd = -1; 482 int err; 483 484 if (!REQ_ARGS(2)) { 485 usage(); 486 return -1; 487 } 488 src = GET_ARG(); 489 490 if (is_prefix(src, "map")) { 491 struct bpf_map_info info = {}; 492 __u32 len = sizeof(info); 493 494 if (!REQ_ARGS(2)) { 495 usage(); 496 return -1; 497 } 498 499 fd = map_parse_fd_and_info(&argc, &argv, &info, &len); 500 if (fd < 0) 501 return -1; 502 503 btf_id = info.btf_id; 504 if (argc && is_prefix(*argv, "key")) { 505 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 506 NEXT_ARG(); 507 } else if (argc && is_prefix(*argv, "value")) { 508 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 509 NEXT_ARG(); 510 } else if (argc && is_prefix(*argv, "all")) { 511 NEXT_ARG(); 512 } else if (argc && is_prefix(*argv, "kv")) { 513 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 514 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 515 NEXT_ARG(); 516 } else { 517 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 518 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 519 } 520 } else if (is_prefix(src, "prog")) { 521 struct bpf_prog_info info = {}; 522 __u32 len = sizeof(info); 523 524 if (!REQ_ARGS(2)) { 525 usage(); 526 return -1; 527 } 528 529 fd = prog_parse_fd(&argc, &argv); 530 if (fd < 0) 531 return -1; 532 533 err = bpf_obj_get_info_by_fd(fd, &info, &len); 534 if (err) { 535 p_err("can't get prog info: %s", strerror(errno)); 536 goto done; 537 } 538 539 btf_id = info.btf_id; 540 } else if (is_prefix(src, "id")) { 541 char *endptr; 542 543 btf_id = strtoul(*argv, &endptr, 0); 544 if (*endptr) { 545 p_err("can't parse %s as ID", *argv); 546 return -1; 547 } 548 NEXT_ARG(); 549 } else if (is_prefix(src, "file")) { 550 if (is_btf_raw(*argv)) 551 btf = btf__parse_raw(*argv); 552 else 553 btf = btf__parse_elf(*argv, NULL); 554 555 if (IS_ERR(btf)) { 556 err = -PTR_ERR(btf); 557 btf = NULL; 558 p_err("failed to load BTF from %s: %s", 559 *argv, strerror(err)); 560 goto done; 561 } 562 NEXT_ARG(); 563 } else { 564 err = -1; 565 p_err("unrecognized BTF source specifier: '%s'", src); 566 goto done; 567 } 568 569 while (argc) { 570 if (is_prefix(*argv, "format")) { 571 NEXT_ARG(); 572 if (argc < 1) { 573 p_err("expecting value for 'format' option\n"); 574 goto done; 575 } 576 if (strcmp(*argv, "c") == 0) { 577 dump_c = true; 578 } else if (strcmp(*argv, "raw") == 0) { 579 dump_c = false; 580 } else { 581 p_err("unrecognized format specifier: '%s', possible values: raw, c", 582 *argv); 583 goto done; 584 } 585 NEXT_ARG(); 586 } else { 587 p_err("unrecognized option: '%s'", *argv); 588 goto done; 589 } 590 } 591 592 if (!btf) { 593 err = btf__get_from_id(btf_id, &btf); 594 if (err) { 595 p_err("get btf by id (%u): %s", btf_id, strerror(err)); 596 goto done; 597 } 598 if (!btf) { 599 err = ENOENT; 600 p_err("can't find btf with ID (%u)", btf_id); 601 goto done; 602 } 603 } 604 605 if (dump_c) { 606 if (json_output) { 607 p_err("JSON output for C-syntax dump is not supported"); 608 err = -ENOTSUP; 609 goto done; 610 } 611 err = dump_btf_c(btf, root_type_ids, root_type_cnt); 612 } else { 613 err = dump_btf_raw(btf, root_type_ids, root_type_cnt); 614 } 615 616 done: 617 close(fd); 618 btf__free(btf); 619 return err; 620 } 621 622 static int btf_parse_fd(int *argc, char ***argv) 623 { 624 unsigned int id; 625 char *endptr; 626 int fd; 627 628 if (!is_prefix(*argv[0], "id")) { 629 p_err("expected 'id', got: '%s'?", **argv); 630 return -1; 631 } 632 NEXT_ARGP(); 633 634 id = strtoul(**argv, &endptr, 0); 635 if (*endptr) { 636 p_err("can't parse %s as ID", **argv); 637 return -1; 638 } 639 NEXT_ARGP(); 640 641 fd = bpf_btf_get_fd_by_id(id); 642 if (fd < 0) 643 p_err("can't get BTF object by id (%u): %s", 644 id, strerror(errno)); 645 646 return fd; 647 } 648 649 static void delete_btf_table(struct btf_attach_table *tab) 650 { 651 struct btf_attach_point *obj; 652 struct hlist_node *tmp; 653 654 unsigned int bkt; 655 656 hash_for_each_safe(tab->table, bkt, tmp, obj, hash) { 657 hash_del(&obj->hash); 658 free(obj); 659 } 660 } 661 662 static int 663 build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type, 664 void *info, __u32 *len) 665 { 666 static const char * const names[] = { 667 [BPF_OBJ_UNKNOWN] = "unknown", 668 [BPF_OBJ_PROG] = "prog", 669 [BPF_OBJ_MAP] = "map", 670 }; 671 struct btf_attach_point *obj_node; 672 __u32 btf_id, id = 0; 673 int err; 674 int fd; 675 676 while (true) { 677 switch (type) { 678 case BPF_OBJ_PROG: 679 err = bpf_prog_get_next_id(id, &id); 680 break; 681 case BPF_OBJ_MAP: 682 err = bpf_map_get_next_id(id, &id); 683 break; 684 default: 685 err = -1; 686 p_err("unexpected object type: %d", type); 687 goto err_free; 688 } 689 if (err) { 690 if (errno == ENOENT) { 691 err = 0; 692 break; 693 } 694 p_err("can't get next %s: %s%s", names[type], 695 strerror(errno), 696 errno == EINVAL ? " -- kernel too old?" : ""); 697 goto err_free; 698 } 699 700 switch (type) { 701 case BPF_OBJ_PROG: 702 fd = bpf_prog_get_fd_by_id(id); 703 break; 704 case BPF_OBJ_MAP: 705 fd = bpf_map_get_fd_by_id(id); 706 break; 707 default: 708 err = -1; 709 p_err("unexpected object type: %d", type); 710 goto err_free; 711 } 712 if (fd < 0) { 713 if (errno == ENOENT) 714 continue; 715 p_err("can't get %s by id (%u): %s", names[type], id, 716 strerror(errno)); 717 err = -1; 718 goto err_free; 719 } 720 721 memset(info, 0, *len); 722 err = bpf_obj_get_info_by_fd(fd, info, len); 723 close(fd); 724 if (err) { 725 p_err("can't get %s info: %s", names[type], 726 strerror(errno)); 727 goto err_free; 728 } 729 730 switch (type) { 731 case BPF_OBJ_PROG: 732 btf_id = ((struct bpf_prog_info *)info)->btf_id; 733 break; 734 case BPF_OBJ_MAP: 735 btf_id = ((struct bpf_map_info *)info)->btf_id; 736 break; 737 default: 738 err = -1; 739 p_err("unexpected object type: %d", type); 740 goto err_free; 741 } 742 if (!btf_id) 743 continue; 744 745 obj_node = calloc(1, sizeof(*obj_node)); 746 if (!obj_node) { 747 p_err("failed to allocate memory: %s", strerror(errno)); 748 goto err_free; 749 } 750 751 obj_node->obj_id = id; 752 obj_node->btf_id = btf_id; 753 hash_add(tab->table, &obj_node->hash, obj_node->btf_id); 754 } 755 756 return 0; 757 758 err_free: 759 delete_btf_table(tab); 760 return err; 761 } 762 763 static int 764 build_btf_tables(struct btf_attach_table *btf_prog_table, 765 struct btf_attach_table *btf_map_table) 766 { 767 struct bpf_prog_info prog_info; 768 __u32 prog_len = sizeof(prog_info); 769 struct bpf_map_info map_info; 770 __u32 map_len = sizeof(map_info); 771 int err = 0; 772 773 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info, 774 &prog_len); 775 if (err) 776 return err; 777 778 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info, 779 &map_len); 780 if (err) { 781 delete_btf_table(btf_prog_table); 782 return err; 783 } 784 785 return 0; 786 } 787 788 static void 789 show_btf_plain(struct bpf_btf_info *info, int fd, 790 struct btf_attach_table *btf_prog_table, 791 struct btf_attach_table *btf_map_table) 792 { 793 struct btf_attach_point *obj; 794 int n; 795 796 printf("%u: ", info->id); 797 printf("size %uB", info->btf_size); 798 799 n = 0; 800 hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) { 801 if (obj->btf_id == info->id) 802 printf("%s%u", n++ == 0 ? " prog_ids " : ",", 803 obj->obj_id); 804 } 805 806 n = 0; 807 hash_for_each_possible(btf_map_table->table, obj, hash, info->id) { 808 if (obj->btf_id == info->id) 809 printf("%s%u", n++ == 0 ? " map_ids " : ",", 810 obj->obj_id); 811 } 812 813 printf("\n"); 814 } 815 816 static void 817 show_btf_json(struct bpf_btf_info *info, int fd, 818 struct btf_attach_table *btf_prog_table, 819 struct btf_attach_table *btf_map_table) 820 { 821 struct btf_attach_point *obj; 822 823 jsonw_start_object(json_wtr); /* btf object */ 824 jsonw_uint_field(json_wtr, "id", info->id); 825 jsonw_uint_field(json_wtr, "size", info->btf_size); 826 827 jsonw_name(json_wtr, "prog_ids"); 828 jsonw_start_array(json_wtr); /* prog_ids */ 829 hash_for_each_possible(btf_prog_table->table, obj, hash, 830 info->id) { 831 if (obj->btf_id == info->id) 832 jsonw_uint(json_wtr, obj->obj_id); 833 } 834 jsonw_end_array(json_wtr); /* prog_ids */ 835 836 jsonw_name(json_wtr, "map_ids"); 837 jsonw_start_array(json_wtr); /* map_ids */ 838 hash_for_each_possible(btf_map_table->table, obj, hash, 839 info->id) { 840 if (obj->btf_id == info->id) 841 jsonw_uint(json_wtr, obj->obj_id); 842 } 843 jsonw_end_array(json_wtr); /* map_ids */ 844 jsonw_end_object(json_wtr); /* btf object */ 845 } 846 847 static int 848 show_btf(int fd, struct btf_attach_table *btf_prog_table, 849 struct btf_attach_table *btf_map_table) 850 { 851 struct bpf_btf_info info = {}; 852 __u32 len = sizeof(info); 853 int err; 854 855 err = bpf_obj_get_info_by_fd(fd, &info, &len); 856 if (err) { 857 p_err("can't get BTF object info: %s", strerror(errno)); 858 return -1; 859 } 860 861 if (json_output) 862 show_btf_json(&info, fd, btf_prog_table, btf_map_table); 863 else 864 show_btf_plain(&info, fd, btf_prog_table, btf_map_table); 865 866 return 0; 867 } 868 869 static int do_show(int argc, char **argv) 870 { 871 struct btf_attach_table btf_prog_table; 872 struct btf_attach_table btf_map_table; 873 int err, fd = -1; 874 __u32 id = 0; 875 876 if (argc == 2) { 877 fd = btf_parse_fd(&argc, &argv); 878 if (fd < 0) 879 return -1; 880 } 881 882 if (argc) { 883 if (fd >= 0) 884 close(fd); 885 return BAD_ARG(); 886 } 887 888 hash_init(btf_prog_table.table); 889 hash_init(btf_map_table.table); 890 err = build_btf_tables(&btf_prog_table, &btf_map_table); 891 if (err) { 892 if (fd >= 0) 893 close(fd); 894 return err; 895 } 896 897 if (fd >= 0) { 898 err = show_btf(fd, &btf_prog_table, &btf_map_table); 899 close(fd); 900 goto exit_free; 901 } 902 903 if (json_output) 904 jsonw_start_array(json_wtr); /* root array */ 905 906 while (true) { 907 err = bpf_btf_get_next_id(id, &id); 908 if (err) { 909 if (errno == ENOENT) { 910 err = 0; 911 break; 912 } 913 p_err("can't get next BTF object: %s%s", 914 strerror(errno), 915 errno == EINVAL ? " -- kernel too old?" : ""); 916 err = -1; 917 break; 918 } 919 920 fd = bpf_btf_get_fd_by_id(id); 921 if (fd < 0) { 922 if (errno == ENOENT) 923 continue; 924 p_err("can't get BTF object by id (%u): %s", 925 id, strerror(errno)); 926 err = -1; 927 break; 928 } 929 930 err = show_btf(fd, &btf_prog_table, &btf_map_table); 931 close(fd); 932 if (err) 933 break; 934 } 935 936 if (json_output) 937 jsonw_end_array(json_wtr); /* root array */ 938 939 exit_free: 940 delete_btf_table(&btf_prog_table); 941 delete_btf_table(&btf_map_table); 942 943 return err; 944 } 945 946 static int do_help(int argc, char **argv) 947 { 948 if (json_output) { 949 jsonw_null(json_wtr); 950 return 0; 951 } 952 953 fprintf(stderr, 954 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n" 955 " %1$s %2$s dump BTF_SRC [format FORMAT]\n" 956 " %1$s %2$s help\n" 957 "\n" 958 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" 959 " FORMAT := { raw | c }\n" 960 " " HELP_SPEC_MAP "\n" 961 " " HELP_SPEC_PROGRAM "\n" 962 " " HELP_SPEC_OPTIONS "\n" 963 "", 964 bin_name, "btf"); 965 966 return 0; 967 } 968 969 static const struct cmd cmds[] = { 970 { "show", do_show }, 971 { "list", do_show }, 972 { "help", do_help }, 973 { "dump", do_dump }, 974 { 0 } 975 }; 976 977 int do_btf(int argc, char **argv) 978 { 979 return cmd_select(cmds, argc, argv, do_help); 980 } 981