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 int start_id = 1; 362 363 if (base_btf) 364 start_id = btf__get_nr_types(base_btf) + 1; 365 366 for (i = start_id; i <= cnt; i++) { 367 t = btf__type_by_id(btf, i); 368 dump_btf_type(btf, i, t); 369 } 370 } 371 372 if (json_output) { 373 jsonw_end_array(json_wtr); 374 jsonw_end_object(json_wtr); 375 } 376 return 0; 377 } 378 379 static void __printf(2, 0) btf_dump_printf(void *ctx, 380 const char *fmt, va_list args) 381 { 382 vfprintf(stdout, fmt, args); 383 } 384 385 static int dump_btf_c(const struct btf *btf, 386 __u32 *root_type_ids, int root_type_cnt) 387 { 388 struct btf_dump *d; 389 int err = 0, i; 390 391 d = btf_dump__new(btf, NULL, NULL, btf_dump_printf); 392 if (IS_ERR(d)) 393 return PTR_ERR(d); 394 395 printf("#ifndef __VMLINUX_H__\n"); 396 printf("#define __VMLINUX_H__\n"); 397 printf("\n"); 398 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 399 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); 400 printf("#endif\n\n"); 401 402 if (root_type_cnt) { 403 for (i = 0; i < root_type_cnt; i++) { 404 err = btf_dump__dump_type(d, root_type_ids[i]); 405 if (err) 406 goto done; 407 } 408 } else { 409 int cnt = btf__get_nr_types(btf); 410 411 for (i = 1; i <= cnt; i++) { 412 err = btf_dump__dump_type(d, i); 413 if (err) 414 goto done; 415 } 416 } 417 418 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 419 printf("#pragma clang attribute pop\n"); 420 printf("#endif\n"); 421 printf("\n"); 422 printf("#endif /* __VMLINUX_H__ */\n"); 423 424 done: 425 btf_dump__free(d); 426 return err; 427 } 428 429 static int do_dump(int argc, char **argv) 430 { 431 struct btf *btf = NULL; 432 __u32 root_type_ids[2]; 433 int root_type_cnt = 0; 434 bool dump_c = false; 435 __u32 btf_id = -1; 436 const char *src; 437 int fd = -1; 438 int err; 439 440 if (!REQ_ARGS(2)) { 441 usage(); 442 return -1; 443 } 444 src = GET_ARG(); 445 if (is_prefix(src, "map")) { 446 struct bpf_map_info info = {}; 447 __u32 len = sizeof(info); 448 449 if (!REQ_ARGS(2)) { 450 usage(); 451 return -1; 452 } 453 454 fd = map_parse_fd_and_info(&argc, &argv, &info, &len); 455 if (fd < 0) 456 return -1; 457 458 btf_id = info.btf_id; 459 if (argc && is_prefix(*argv, "key")) { 460 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 461 NEXT_ARG(); 462 } else if (argc && is_prefix(*argv, "value")) { 463 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 464 NEXT_ARG(); 465 } else if (argc && is_prefix(*argv, "all")) { 466 NEXT_ARG(); 467 } else if (argc && is_prefix(*argv, "kv")) { 468 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 469 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 470 NEXT_ARG(); 471 } else { 472 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 473 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 474 } 475 } else if (is_prefix(src, "prog")) { 476 struct bpf_prog_info info = {}; 477 __u32 len = sizeof(info); 478 479 if (!REQ_ARGS(2)) { 480 usage(); 481 return -1; 482 } 483 484 fd = prog_parse_fd(&argc, &argv); 485 if (fd < 0) 486 return -1; 487 488 err = bpf_obj_get_info_by_fd(fd, &info, &len); 489 if (err) { 490 p_err("can't get prog info: %s", strerror(errno)); 491 goto done; 492 } 493 494 btf_id = info.btf_id; 495 } else if (is_prefix(src, "id")) { 496 char *endptr; 497 498 btf_id = strtoul(*argv, &endptr, 0); 499 if (*endptr) { 500 p_err("can't parse %s as ID", *argv); 501 return -1; 502 } 503 NEXT_ARG(); 504 } else if (is_prefix(src, "file")) { 505 btf = btf__parse_split(*argv, base_btf); 506 if (IS_ERR(btf)) { 507 err = -PTR_ERR(btf); 508 btf = NULL; 509 p_err("failed to load BTF from %s: %s", 510 *argv, strerror(err)); 511 goto done; 512 } 513 NEXT_ARG(); 514 } else { 515 err = -1; 516 p_err("unrecognized BTF source specifier: '%s'", src); 517 goto done; 518 } 519 520 while (argc) { 521 if (is_prefix(*argv, "format")) { 522 NEXT_ARG(); 523 if (argc < 1) { 524 p_err("expecting value for 'format' option\n"); 525 goto done; 526 } 527 if (strcmp(*argv, "c") == 0) { 528 dump_c = true; 529 } else if (strcmp(*argv, "raw") == 0) { 530 dump_c = false; 531 } else { 532 p_err("unrecognized format specifier: '%s', possible values: raw, c", 533 *argv); 534 goto done; 535 } 536 NEXT_ARG(); 537 } else { 538 p_err("unrecognized option: '%s'", *argv); 539 goto done; 540 } 541 } 542 543 if (!btf) { 544 err = btf__get_from_id(btf_id, &btf); 545 if (err) { 546 p_err("get btf by id (%u): %s", btf_id, strerror(err)); 547 goto done; 548 } 549 if (!btf) { 550 err = -ENOENT; 551 p_err("can't find btf with ID (%u)", btf_id); 552 goto done; 553 } 554 } 555 556 if (dump_c) { 557 if (json_output) { 558 p_err("JSON output for C-syntax dump is not supported"); 559 err = -ENOTSUP; 560 goto done; 561 } 562 err = dump_btf_c(btf, root_type_ids, root_type_cnt); 563 } else { 564 err = dump_btf_raw(btf, root_type_ids, root_type_cnt); 565 } 566 567 done: 568 close(fd); 569 btf__free(btf); 570 return err; 571 } 572 573 static int btf_parse_fd(int *argc, char ***argv) 574 { 575 unsigned int id; 576 char *endptr; 577 int fd; 578 579 if (!is_prefix(*argv[0], "id")) { 580 p_err("expected 'id', got: '%s'?", **argv); 581 return -1; 582 } 583 NEXT_ARGP(); 584 585 id = strtoul(**argv, &endptr, 0); 586 if (*endptr) { 587 p_err("can't parse %s as ID", **argv); 588 return -1; 589 } 590 NEXT_ARGP(); 591 592 fd = bpf_btf_get_fd_by_id(id); 593 if (fd < 0) 594 p_err("can't get BTF object by id (%u): %s", 595 id, strerror(errno)); 596 597 return fd; 598 } 599 600 static void delete_btf_table(struct btf_attach_table *tab) 601 { 602 struct btf_attach_point *obj; 603 struct hlist_node *tmp; 604 605 unsigned int bkt; 606 607 hash_for_each_safe(tab->table, bkt, tmp, obj, hash) { 608 hash_del(&obj->hash); 609 free(obj); 610 } 611 } 612 613 static int 614 build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type, 615 void *info, __u32 *len) 616 { 617 static const char * const names[] = { 618 [BPF_OBJ_UNKNOWN] = "unknown", 619 [BPF_OBJ_PROG] = "prog", 620 [BPF_OBJ_MAP] = "map", 621 }; 622 struct btf_attach_point *obj_node; 623 __u32 btf_id, id = 0; 624 int err; 625 int fd; 626 627 while (true) { 628 switch (type) { 629 case BPF_OBJ_PROG: 630 err = bpf_prog_get_next_id(id, &id); 631 break; 632 case BPF_OBJ_MAP: 633 err = bpf_map_get_next_id(id, &id); 634 break; 635 default: 636 err = -1; 637 p_err("unexpected object type: %d", type); 638 goto err_free; 639 } 640 if (err) { 641 if (errno == ENOENT) { 642 err = 0; 643 break; 644 } 645 p_err("can't get next %s: %s%s", names[type], 646 strerror(errno), 647 errno == EINVAL ? " -- kernel too old?" : ""); 648 goto err_free; 649 } 650 651 switch (type) { 652 case BPF_OBJ_PROG: 653 fd = bpf_prog_get_fd_by_id(id); 654 break; 655 case BPF_OBJ_MAP: 656 fd = bpf_map_get_fd_by_id(id); 657 break; 658 default: 659 err = -1; 660 p_err("unexpected object type: %d", type); 661 goto err_free; 662 } 663 if (fd < 0) { 664 if (errno == ENOENT) 665 continue; 666 p_err("can't get %s by id (%u): %s", names[type], id, 667 strerror(errno)); 668 err = -1; 669 goto err_free; 670 } 671 672 memset(info, 0, *len); 673 err = bpf_obj_get_info_by_fd(fd, info, len); 674 close(fd); 675 if (err) { 676 p_err("can't get %s info: %s", names[type], 677 strerror(errno)); 678 goto err_free; 679 } 680 681 switch (type) { 682 case BPF_OBJ_PROG: 683 btf_id = ((struct bpf_prog_info *)info)->btf_id; 684 break; 685 case BPF_OBJ_MAP: 686 btf_id = ((struct bpf_map_info *)info)->btf_id; 687 break; 688 default: 689 err = -1; 690 p_err("unexpected object type: %d", type); 691 goto err_free; 692 } 693 if (!btf_id) 694 continue; 695 696 obj_node = calloc(1, sizeof(*obj_node)); 697 if (!obj_node) { 698 p_err("failed to allocate memory: %s", strerror(errno)); 699 goto err_free; 700 } 701 702 obj_node->obj_id = id; 703 obj_node->btf_id = btf_id; 704 hash_add(tab->table, &obj_node->hash, obj_node->btf_id); 705 } 706 707 return 0; 708 709 err_free: 710 delete_btf_table(tab); 711 return err; 712 } 713 714 static int 715 build_btf_tables(struct btf_attach_table *btf_prog_table, 716 struct btf_attach_table *btf_map_table) 717 { 718 struct bpf_prog_info prog_info; 719 __u32 prog_len = sizeof(prog_info); 720 struct bpf_map_info map_info; 721 __u32 map_len = sizeof(map_info); 722 int err = 0; 723 724 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info, 725 &prog_len); 726 if (err) 727 return err; 728 729 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info, 730 &map_len); 731 if (err) { 732 delete_btf_table(btf_prog_table); 733 return err; 734 } 735 736 return 0; 737 } 738 739 static void 740 show_btf_plain(struct bpf_btf_info *info, int fd, 741 struct btf_attach_table *btf_prog_table, 742 struct btf_attach_table *btf_map_table) 743 { 744 struct btf_attach_point *obj; 745 const char *name = u64_to_ptr(info->name); 746 int n; 747 748 printf("%u: ", info->id); 749 if (info->kernel_btf) 750 printf("name [%s] ", name); 751 else if (name && name[0]) 752 printf("name %s ", name); 753 printf("size %uB", info->btf_size); 754 755 n = 0; 756 hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) { 757 if (obj->btf_id == info->id) 758 printf("%s%u", n++ == 0 ? " prog_ids " : ",", 759 obj->obj_id); 760 } 761 762 n = 0; 763 hash_for_each_possible(btf_map_table->table, obj, hash, info->id) { 764 if (obj->btf_id == info->id) 765 printf("%s%u", n++ == 0 ? " map_ids " : ",", 766 obj->obj_id); 767 } 768 emit_obj_refs_plain(&refs_table, info->id, "\n\tpids "); 769 770 printf("\n"); 771 } 772 773 static void 774 show_btf_json(struct bpf_btf_info *info, int fd, 775 struct btf_attach_table *btf_prog_table, 776 struct btf_attach_table *btf_map_table) 777 { 778 struct btf_attach_point *obj; 779 const char *name = u64_to_ptr(info->name); 780 781 jsonw_start_object(json_wtr); /* btf object */ 782 jsonw_uint_field(json_wtr, "id", info->id); 783 jsonw_uint_field(json_wtr, "size", info->btf_size); 784 785 jsonw_name(json_wtr, "prog_ids"); 786 jsonw_start_array(json_wtr); /* prog_ids */ 787 hash_for_each_possible(btf_prog_table->table, obj, hash, 788 info->id) { 789 if (obj->btf_id == info->id) 790 jsonw_uint(json_wtr, obj->obj_id); 791 } 792 jsonw_end_array(json_wtr); /* prog_ids */ 793 794 jsonw_name(json_wtr, "map_ids"); 795 jsonw_start_array(json_wtr); /* map_ids */ 796 hash_for_each_possible(btf_map_table->table, obj, hash, 797 info->id) { 798 if (obj->btf_id == info->id) 799 jsonw_uint(json_wtr, obj->obj_id); 800 } 801 jsonw_end_array(json_wtr); /* map_ids */ 802 803 emit_obj_refs_json(&refs_table, info->id, json_wtr); /* pids */ 804 805 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf); 806 807 if (name && name[0]) 808 jsonw_string_field(json_wtr, "name", name); 809 810 jsonw_end_object(json_wtr); /* btf object */ 811 } 812 813 static int 814 show_btf(int fd, struct btf_attach_table *btf_prog_table, 815 struct btf_attach_table *btf_map_table) 816 { 817 struct bpf_btf_info info; 818 __u32 len = sizeof(info); 819 char name[64]; 820 int err; 821 822 memset(&info, 0, sizeof(info)); 823 err = bpf_obj_get_info_by_fd(fd, &info, &len); 824 if (err) { 825 p_err("can't get BTF object info: %s", strerror(errno)); 826 return -1; 827 } 828 /* if kernel support emitting BTF object name, pass name pointer */ 829 if (info.name_len) { 830 memset(&info, 0, sizeof(info)); 831 info.name_len = sizeof(name); 832 info.name = ptr_to_u64(name); 833 len = sizeof(info); 834 835 err = bpf_obj_get_info_by_fd(fd, &info, &len); 836 if (err) { 837 p_err("can't get BTF object info: %s", strerror(errno)); 838 return -1; 839 } 840 } 841 842 if (json_output) 843 show_btf_json(&info, fd, btf_prog_table, btf_map_table); 844 else 845 show_btf_plain(&info, fd, btf_prog_table, btf_map_table); 846 847 return 0; 848 } 849 850 static int do_show(int argc, char **argv) 851 { 852 struct btf_attach_table btf_prog_table; 853 struct btf_attach_table btf_map_table; 854 int err, fd = -1; 855 __u32 id = 0; 856 857 if (argc == 2) { 858 fd = btf_parse_fd(&argc, &argv); 859 if (fd < 0) 860 return -1; 861 } 862 863 if (argc) { 864 if (fd >= 0) 865 close(fd); 866 return BAD_ARG(); 867 } 868 869 hash_init(btf_prog_table.table); 870 hash_init(btf_map_table.table); 871 err = build_btf_tables(&btf_prog_table, &btf_map_table); 872 if (err) { 873 if (fd >= 0) 874 close(fd); 875 return err; 876 } 877 build_obj_refs_table(&refs_table, BPF_OBJ_BTF); 878 879 if (fd >= 0) { 880 err = show_btf(fd, &btf_prog_table, &btf_map_table); 881 close(fd); 882 goto exit_free; 883 } 884 885 if (json_output) 886 jsonw_start_array(json_wtr); /* root array */ 887 888 while (true) { 889 err = bpf_btf_get_next_id(id, &id); 890 if (err) { 891 if (errno == ENOENT) { 892 err = 0; 893 break; 894 } 895 p_err("can't get next BTF object: %s%s", 896 strerror(errno), 897 errno == EINVAL ? " -- kernel too old?" : ""); 898 err = -1; 899 break; 900 } 901 902 fd = bpf_btf_get_fd_by_id(id); 903 if (fd < 0) { 904 if (errno == ENOENT) 905 continue; 906 p_err("can't get BTF object by id (%u): %s", 907 id, strerror(errno)); 908 err = -1; 909 break; 910 } 911 912 err = show_btf(fd, &btf_prog_table, &btf_map_table); 913 close(fd); 914 if (err) 915 break; 916 } 917 918 if (json_output) 919 jsonw_end_array(json_wtr); /* root array */ 920 921 exit_free: 922 delete_btf_table(&btf_prog_table); 923 delete_btf_table(&btf_map_table); 924 delete_obj_refs_table(&refs_table); 925 926 return err; 927 } 928 929 static int do_help(int argc, char **argv) 930 { 931 if (json_output) { 932 jsonw_null(json_wtr); 933 return 0; 934 } 935 936 fprintf(stderr, 937 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n" 938 " %1$s %2$s dump BTF_SRC [format FORMAT]\n" 939 " %1$s %2$s help\n" 940 "\n" 941 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" 942 " FORMAT := { raw | c }\n" 943 " " HELP_SPEC_MAP "\n" 944 " " HELP_SPEC_PROGRAM "\n" 945 " " HELP_SPEC_OPTIONS "\n" 946 "", 947 bin_name, "btf"); 948 949 return 0; 950 } 951 952 static const struct cmd cmds[] = { 953 { "show", do_show }, 954 { "list", do_show }, 955 { "help", do_help }, 956 { "dump", do_dump }, 957 { 0 } 958 }; 959 960 int do_btf(int argc, char **argv) 961 { 962 return cmd_select(cmds, argc, argv, do_help); 963 } 964