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