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 <linux/btf.h> 12 #include <sys/types.h> 13 #include <sys/stat.h> 14 15 #include <bpf/bpf.h> 16 #include <bpf/btf.h> 17 #include <bpf/hashmap.h> 18 #include <bpf/libbpf.h> 19 20 #include "json_writer.h" 21 #include "main.h" 22 23 static const char * const btf_kind_str[NR_BTF_KINDS] = { 24 [BTF_KIND_UNKN] = "UNKNOWN", 25 [BTF_KIND_INT] = "INT", 26 [BTF_KIND_PTR] = "PTR", 27 [BTF_KIND_ARRAY] = "ARRAY", 28 [BTF_KIND_STRUCT] = "STRUCT", 29 [BTF_KIND_UNION] = "UNION", 30 [BTF_KIND_ENUM] = "ENUM", 31 [BTF_KIND_FWD] = "FWD", 32 [BTF_KIND_TYPEDEF] = "TYPEDEF", 33 [BTF_KIND_VOLATILE] = "VOLATILE", 34 [BTF_KIND_CONST] = "CONST", 35 [BTF_KIND_RESTRICT] = "RESTRICT", 36 [BTF_KIND_FUNC] = "FUNC", 37 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", 38 [BTF_KIND_VAR] = "VAR", 39 [BTF_KIND_DATASEC] = "DATASEC", 40 [BTF_KIND_FLOAT] = "FLOAT", 41 [BTF_KIND_DECL_TAG] = "DECL_TAG", 42 [BTF_KIND_TYPE_TAG] = "TYPE_TAG", 43 [BTF_KIND_ENUM64] = "ENUM64", 44 }; 45 46 static const char *btf_int_enc_str(__u8 encoding) 47 { 48 switch (encoding) { 49 case 0: 50 return "(none)"; 51 case BTF_INT_SIGNED: 52 return "SIGNED"; 53 case BTF_INT_CHAR: 54 return "CHAR"; 55 case BTF_INT_BOOL: 56 return "BOOL"; 57 default: 58 return "UNKN"; 59 } 60 } 61 62 static const char *btf_var_linkage_str(__u32 linkage) 63 { 64 switch (linkage) { 65 case BTF_VAR_STATIC: 66 return "static"; 67 case BTF_VAR_GLOBAL_ALLOCATED: 68 return "global"; 69 case BTF_VAR_GLOBAL_EXTERN: 70 return "extern"; 71 default: 72 return "(unknown)"; 73 } 74 } 75 76 static const char *btf_func_linkage_str(const struct btf_type *t) 77 { 78 switch (btf_vlen(t)) { 79 case BTF_FUNC_STATIC: 80 return "static"; 81 case BTF_FUNC_GLOBAL: 82 return "global"; 83 case BTF_FUNC_EXTERN: 84 return "extern"; 85 default: 86 return "(unknown)"; 87 } 88 } 89 90 static const char *btf_str(const struct btf *btf, __u32 off) 91 { 92 if (!off) 93 return "(anon)"; 94 return btf__name_by_offset(btf, off) ? : "(invalid)"; 95 } 96 97 static int btf_kind_safe(int kind) 98 { 99 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; 100 } 101 102 static int dump_btf_type(const struct btf *btf, __u32 id, 103 const struct btf_type *t) 104 { 105 json_writer_t *w = json_wtr; 106 int kind = btf_kind(t); 107 108 if (json_output) { 109 jsonw_start_object(w); 110 jsonw_uint_field(w, "id", id); 111 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]); 112 jsonw_string_field(w, "name", btf_str(btf, t->name_off)); 113 } else { 114 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)], 115 btf_str(btf, t->name_off)); 116 } 117 118 switch (kind) { 119 case BTF_KIND_INT: { 120 __u32 v = *(__u32 *)(t + 1); 121 const char *enc; 122 123 enc = btf_int_enc_str(BTF_INT_ENCODING(v)); 124 125 if (json_output) { 126 jsonw_uint_field(w, "size", t->size); 127 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v)); 128 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v)); 129 jsonw_string_field(w, "encoding", enc); 130 } else { 131 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s", 132 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v), 133 enc); 134 } 135 break; 136 } 137 case BTF_KIND_PTR: 138 case BTF_KIND_CONST: 139 case BTF_KIND_VOLATILE: 140 case BTF_KIND_RESTRICT: 141 case BTF_KIND_TYPEDEF: 142 case BTF_KIND_TYPE_TAG: 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 const char *encoding; 212 int i; 213 214 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED"; 215 if (json_output) { 216 jsonw_string_field(w, "encoding", encoding); 217 jsonw_uint_field(w, "size", t->size); 218 jsonw_uint_field(w, "vlen", vlen); 219 jsonw_name(w, "values"); 220 jsonw_start_array(w); 221 } else { 222 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen); 223 } 224 for (i = 0; i < vlen; i++, v++) { 225 const char *name = btf_str(btf, v->name_off); 226 227 if (json_output) { 228 jsonw_start_object(w); 229 jsonw_string_field(w, "name", name); 230 if (btf_kflag(t)) 231 jsonw_int_field(w, "val", v->val); 232 else 233 jsonw_uint_field(w, "val", v->val); 234 jsonw_end_object(w); 235 } else { 236 if (btf_kflag(t)) 237 printf("\n\t'%s' val=%d", name, v->val); 238 else 239 printf("\n\t'%s' val=%u", name, v->val); 240 } 241 } 242 if (json_output) 243 jsonw_end_array(w); 244 break; 245 } 246 case BTF_KIND_ENUM64: { 247 const struct btf_enum64 *v = btf_enum64(t); 248 __u16 vlen = btf_vlen(t); 249 const char *encoding; 250 int i; 251 252 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED"; 253 if (json_output) { 254 jsonw_string_field(w, "encoding", encoding); 255 jsonw_uint_field(w, "size", t->size); 256 jsonw_uint_field(w, "vlen", vlen); 257 jsonw_name(w, "values"); 258 jsonw_start_array(w); 259 } else { 260 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen); 261 } 262 for (i = 0; i < vlen; i++, v++) { 263 const char *name = btf_str(btf, v->name_off); 264 __u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32; 265 266 if (json_output) { 267 jsonw_start_object(w); 268 jsonw_string_field(w, "name", name); 269 if (btf_kflag(t)) 270 jsonw_int_field(w, "val", val); 271 else 272 jsonw_uint_field(w, "val", val); 273 jsonw_end_object(w); 274 } else { 275 if (btf_kflag(t)) 276 printf("\n\t'%s' val=%lldLL", name, 277 (unsigned long long)val); 278 else 279 printf("\n\t'%s' val=%lluULL", name, 280 (unsigned long long)val); 281 } 282 } 283 if (json_output) 284 jsonw_end_array(w); 285 break; 286 } 287 case BTF_KIND_FWD: { 288 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union" 289 : "struct"; 290 291 if (json_output) 292 jsonw_string_field(w, "fwd_kind", fwd_kind); 293 else 294 printf(" fwd_kind=%s", fwd_kind); 295 break; 296 } 297 case BTF_KIND_FUNC: { 298 const char *linkage = btf_func_linkage_str(t); 299 300 if (json_output) { 301 jsonw_uint_field(w, "type_id", t->type); 302 jsonw_string_field(w, "linkage", linkage); 303 } else { 304 printf(" type_id=%u linkage=%s", t->type, linkage); 305 } 306 break; 307 } 308 case BTF_KIND_FUNC_PROTO: { 309 const struct btf_param *p = (const void *)(t + 1); 310 __u16 vlen = BTF_INFO_VLEN(t->info); 311 int i; 312 313 if (json_output) { 314 jsonw_uint_field(w, "ret_type_id", t->type); 315 jsonw_uint_field(w, "vlen", vlen); 316 jsonw_name(w, "params"); 317 jsonw_start_array(w); 318 } else { 319 printf(" ret_type_id=%u vlen=%u", t->type, vlen); 320 } 321 for (i = 0; i < vlen; i++, p++) { 322 const char *name = btf_str(btf, p->name_off); 323 324 if (json_output) { 325 jsonw_start_object(w); 326 jsonw_string_field(w, "name", name); 327 jsonw_uint_field(w, "type_id", p->type); 328 jsonw_end_object(w); 329 } else { 330 printf("\n\t'%s' type_id=%u", name, p->type); 331 } 332 } 333 if (json_output) 334 jsonw_end_array(w); 335 break; 336 } 337 case BTF_KIND_VAR: { 338 const struct btf_var *v = (const void *)(t + 1); 339 const char *linkage; 340 341 linkage = btf_var_linkage_str(v->linkage); 342 343 if (json_output) { 344 jsonw_uint_field(w, "type_id", t->type); 345 jsonw_string_field(w, "linkage", linkage); 346 } else { 347 printf(" type_id=%u, linkage=%s", t->type, linkage); 348 } 349 break; 350 } 351 case BTF_KIND_DATASEC: { 352 const struct btf_var_secinfo *v = (const void *)(t + 1); 353 const struct btf_type *vt; 354 __u16 vlen = BTF_INFO_VLEN(t->info); 355 int i; 356 357 if (json_output) { 358 jsonw_uint_field(w, "size", t->size); 359 jsonw_uint_field(w, "vlen", vlen); 360 jsonw_name(w, "vars"); 361 jsonw_start_array(w); 362 } else { 363 printf(" size=%u vlen=%u", t->size, vlen); 364 } 365 for (i = 0; i < vlen; i++, v++) { 366 if (json_output) { 367 jsonw_start_object(w); 368 jsonw_uint_field(w, "type_id", v->type); 369 jsonw_uint_field(w, "offset", v->offset); 370 jsonw_uint_field(w, "size", v->size); 371 jsonw_end_object(w); 372 } else { 373 printf("\n\ttype_id=%u offset=%u size=%u", 374 v->type, v->offset, v->size); 375 376 if (v->type < btf__type_cnt(btf)) { 377 vt = btf__type_by_id(btf, v->type); 378 printf(" (%s '%s')", 379 btf_kind_str[btf_kind_safe(btf_kind(vt))], 380 btf_str(btf, vt->name_off)); 381 } 382 } 383 } 384 if (json_output) 385 jsonw_end_array(w); 386 break; 387 } 388 case BTF_KIND_FLOAT: { 389 if (json_output) 390 jsonw_uint_field(w, "size", t->size); 391 else 392 printf(" size=%u", t->size); 393 break; 394 } 395 case BTF_KIND_DECL_TAG: { 396 const struct btf_decl_tag *tag = (const void *)(t + 1); 397 398 if (json_output) { 399 jsonw_uint_field(w, "type_id", t->type); 400 jsonw_int_field(w, "component_idx", tag->component_idx); 401 } else { 402 printf(" type_id=%u component_idx=%d", t->type, tag->component_idx); 403 } 404 break; 405 } 406 default: 407 break; 408 } 409 410 if (json_output) 411 jsonw_end_object(json_wtr); 412 else 413 printf("\n"); 414 415 return 0; 416 } 417 418 static int dump_btf_raw(const struct btf *btf, 419 __u32 *root_type_ids, int root_type_cnt) 420 { 421 const struct btf_type *t; 422 int i; 423 424 if (json_output) { 425 jsonw_start_object(json_wtr); 426 jsonw_name(json_wtr, "types"); 427 jsonw_start_array(json_wtr); 428 } 429 430 if (root_type_cnt) { 431 for (i = 0; i < root_type_cnt; i++) { 432 t = btf__type_by_id(btf, root_type_ids[i]); 433 dump_btf_type(btf, root_type_ids[i], t); 434 } 435 } else { 436 const struct btf *base; 437 int cnt = btf__type_cnt(btf); 438 int start_id = 1; 439 440 base = btf__base_btf(btf); 441 if (base) 442 start_id = btf__type_cnt(base); 443 444 for (i = start_id; i < cnt; i++) { 445 t = btf__type_by_id(btf, i); 446 dump_btf_type(btf, i, t); 447 } 448 } 449 450 if (json_output) { 451 jsonw_end_array(json_wtr); 452 jsonw_end_object(json_wtr); 453 } 454 return 0; 455 } 456 457 static void __printf(2, 0) btf_dump_printf(void *ctx, 458 const char *fmt, va_list args) 459 { 460 vfprintf(stdout, fmt, args); 461 } 462 463 static int dump_btf_c(const struct btf *btf, 464 __u32 *root_type_ids, int root_type_cnt) 465 { 466 struct btf_dump *d; 467 int err = 0, i; 468 469 d = btf_dump__new(btf, btf_dump_printf, NULL, NULL); 470 if (!d) 471 return -errno; 472 473 printf("#ifndef __VMLINUX_H__\n"); 474 printf("#define __VMLINUX_H__\n"); 475 printf("\n"); 476 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 477 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n"); 478 printf("#endif\n\n"); 479 480 if (root_type_cnt) { 481 for (i = 0; i < root_type_cnt; i++) { 482 err = btf_dump__dump_type(d, root_type_ids[i]); 483 if (err) 484 goto done; 485 } 486 } else { 487 int cnt = btf__type_cnt(btf); 488 489 for (i = 1; i < cnt; i++) { 490 err = btf_dump__dump_type(d, i); 491 if (err) 492 goto done; 493 } 494 } 495 496 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n"); 497 printf("#pragma clang attribute pop\n"); 498 printf("#endif\n"); 499 printf("\n"); 500 printf("#endif /* __VMLINUX_H__ */\n"); 501 502 done: 503 btf_dump__free(d); 504 return err; 505 } 506 507 static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux"; 508 509 static struct btf *get_vmlinux_btf_from_sysfs(void) 510 { 511 struct btf *base; 512 513 base = btf__parse(sysfs_vmlinux, NULL); 514 if (!base) 515 p_err("failed to parse vmlinux BTF at '%s': %d\n", 516 sysfs_vmlinux, -errno); 517 518 return base; 519 } 520 521 #define BTF_NAME_BUFF_LEN 64 522 523 static bool btf_is_kernel_module(__u32 btf_id) 524 { 525 struct bpf_btf_info btf_info = {}; 526 char btf_name[BTF_NAME_BUFF_LEN]; 527 int btf_fd; 528 __u32 len; 529 int err; 530 531 btf_fd = bpf_btf_get_fd_by_id(btf_id); 532 if (btf_fd < 0) { 533 p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno)); 534 return false; 535 } 536 537 len = sizeof(btf_info); 538 btf_info.name = ptr_to_u64(btf_name); 539 btf_info.name_len = sizeof(btf_name); 540 err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len); 541 close(btf_fd); 542 if (err) { 543 p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno)); 544 return false; 545 } 546 547 return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0; 548 } 549 550 static int do_dump(int argc, char **argv) 551 { 552 struct btf *btf = NULL, *base = NULL; 553 __u32 root_type_ids[2]; 554 int root_type_cnt = 0; 555 bool dump_c = false; 556 __u32 btf_id = -1; 557 const char *src; 558 int fd = -1; 559 int err = 0; 560 561 if (!REQ_ARGS(2)) { 562 usage(); 563 return -1; 564 } 565 src = GET_ARG(); 566 if (is_prefix(src, "map")) { 567 struct bpf_map_info info = {}; 568 __u32 len = sizeof(info); 569 570 if (!REQ_ARGS(2)) { 571 usage(); 572 return -1; 573 } 574 575 fd = map_parse_fd_and_info(&argc, &argv, &info, &len); 576 if (fd < 0) 577 return -1; 578 579 btf_id = info.btf_id; 580 if (argc && is_prefix(*argv, "key")) { 581 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 582 NEXT_ARG(); 583 } else if (argc && is_prefix(*argv, "value")) { 584 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 585 NEXT_ARG(); 586 } else if (argc && is_prefix(*argv, "all")) { 587 NEXT_ARG(); 588 } else if (argc && is_prefix(*argv, "kv")) { 589 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 590 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 591 NEXT_ARG(); 592 } else { 593 root_type_ids[root_type_cnt++] = info.btf_key_type_id; 594 root_type_ids[root_type_cnt++] = info.btf_value_type_id; 595 } 596 } else if (is_prefix(src, "prog")) { 597 struct bpf_prog_info info = {}; 598 __u32 len = sizeof(info); 599 600 if (!REQ_ARGS(2)) { 601 usage(); 602 return -1; 603 } 604 605 fd = prog_parse_fd(&argc, &argv); 606 if (fd < 0) 607 return -1; 608 609 err = bpf_obj_get_info_by_fd(fd, &info, &len); 610 if (err) { 611 p_err("can't get prog info: %s", strerror(errno)); 612 goto done; 613 } 614 615 btf_id = info.btf_id; 616 } else if (is_prefix(src, "id")) { 617 char *endptr; 618 619 btf_id = strtoul(*argv, &endptr, 0); 620 if (*endptr) { 621 p_err("can't parse %s as ID", *argv); 622 return -1; 623 } 624 NEXT_ARG(); 625 } else if (is_prefix(src, "file")) { 626 const char sysfs_prefix[] = "/sys/kernel/btf/"; 627 628 if (!base_btf && 629 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 && 630 strcmp(*argv, sysfs_vmlinux) != 0) 631 base = get_vmlinux_btf_from_sysfs(); 632 633 btf = btf__parse_split(*argv, base ?: base_btf); 634 if (!btf) { 635 err = -errno; 636 p_err("failed to load BTF from %s: %s", 637 *argv, strerror(errno)); 638 goto done; 639 } 640 NEXT_ARG(); 641 } else { 642 err = -1; 643 p_err("unrecognized BTF source specifier: '%s'", src); 644 goto done; 645 } 646 647 while (argc) { 648 if (is_prefix(*argv, "format")) { 649 NEXT_ARG(); 650 if (argc < 1) { 651 p_err("expecting value for 'format' option\n"); 652 err = -EINVAL; 653 goto done; 654 } 655 if (strcmp(*argv, "c") == 0) { 656 dump_c = true; 657 } else if (strcmp(*argv, "raw") == 0) { 658 dump_c = false; 659 } else { 660 p_err("unrecognized format specifier: '%s', possible values: raw, c", 661 *argv); 662 err = -EINVAL; 663 goto done; 664 } 665 NEXT_ARG(); 666 } else { 667 p_err("unrecognized option: '%s'", *argv); 668 err = -EINVAL; 669 goto done; 670 } 671 } 672 673 if (!btf) { 674 if (!base_btf && btf_is_kernel_module(btf_id)) { 675 p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)", 676 sysfs_vmlinux); 677 base_btf = get_vmlinux_btf_from_sysfs(); 678 } 679 680 btf = btf__load_from_kernel_by_id_split(btf_id, base_btf); 681 if (!btf) { 682 err = -errno; 683 p_err("get btf by id (%u): %s", btf_id, strerror(errno)); 684 goto done; 685 } 686 } 687 688 if (dump_c) { 689 if (json_output) { 690 p_err("JSON output for C-syntax dump is not supported"); 691 err = -ENOTSUP; 692 goto done; 693 } 694 err = dump_btf_c(btf, root_type_ids, root_type_cnt); 695 } else { 696 err = dump_btf_raw(btf, root_type_ids, root_type_cnt); 697 } 698 699 done: 700 close(fd); 701 btf__free(btf); 702 btf__free(base); 703 return err; 704 } 705 706 static int btf_parse_fd(int *argc, char ***argv) 707 { 708 unsigned int id; 709 char *endptr; 710 int fd; 711 712 if (!is_prefix(*argv[0], "id")) { 713 p_err("expected 'id', got: '%s'?", **argv); 714 return -1; 715 } 716 NEXT_ARGP(); 717 718 id = strtoul(**argv, &endptr, 0); 719 if (*endptr) { 720 p_err("can't parse %s as ID", **argv); 721 return -1; 722 } 723 NEXT_ARGP(); 724 725 fd = bpf_btf_get_fd_by_id(id); 726 if (fd < 0) 727 p_err("can't get BTF object by id (%u): %s", 728 id, strerror(errno)); 729 730 return fd; 731 } 732 733 static int 734 build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type, 735 void *info, __u32 *len) 736 { 737 static const char * const names[] = { 738 [BPF_OBJ_UNKNOWN] = "unknown", 739 [BPF_OBJ_PROG] = "prog", 740 [BPF_OBJ_MAP] = "map", 741 }; 742 __u32 btf_id, id = 0; 743 int err; 744 int fd; 745 746 while (true) { 747 switch (type) { 748 case BPF_OBJ_PROG: 749 err = bpf_prog_get_next_id(id, &id); 750 break; 751 case BPF_OBJ_MAP: 752 err = bpf_map_get_next_id(id, &id); 753 break; 754 default: 755 err = -1; 756 p_err("unexpected object type: %d", type); 757 goto err_free; 758 } 759 if (err) { 760 if (errno == ENOENT) { 761 err = 0; 762 break; 763 } 764 p_err("can't get next %s: %s%s", names[type], 765 strerror(errno), 766 errno == EINVAL ? " -- kernel too old?" : ""); 767 goto err_free; 768 } 769 770 switch (type) { 771 case BPF_OBJ_PROG: 772 fd = bpf_prog_get_fd_by_id(id); 773 break; 774 case BPF_OBJ_MAP: 775 fd = bpf_map_get_fd_by_id(id); 776 break; 777 default: 778 err = -1; 779 p_err("unexpected object type: %d", type); 780 goto err_free; 781 } 782 if (fd < 0) { 783 if (errno == ENOENT) 784 continue; 785 p_err("can't get %s by id (%u): %s", names[type], id, 786 strerror(errno)); 787 err = -1; 788 goto err_free; 789 } 790 791 memset(info, 0, *len); 792 err = bpf_obj_get_info_by_fd(fd, info, len); 793 close(fd); 794 if (err) { 795 p_err("can't get %s info: %s", names[type], 796 strerror(errno)); 797 goto err_free; 798 } 799 800 switch (type) { 801 case BPF_OBJ_PROG: 802 btf_id = ((struct bpf_prog_info *)info)->btf_id; 803 break; 804 case BPF_OBJ_MAP: 805 btf_id = ((struct bpf_map_info *)info)->btf_id; 806 break; 807 default: 808 err = -1; 809 p_err("unexpected object type: %d", type); 810 goto err_free; 811 } 812 if (!btf_id) 813 continue; 814 815 err = hashmap__append(tab, btf_id, id); 816 if (err) { 817 p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s", 818 btf_id, id, strerror(-err)); 819 goto err_free; 820 } 821 } 822 823 return 0; 824 825 err_free: 826 hashmap__free(tab); 827 return err; 828 } 829 830 static int 831 build_btf_tables(struct hashmap *btf_prog_table, 832 struct hashmap *btf_map_table) 833 { 834 struct bpf_prog_info prog_info; 835 __u32 prog_len = sizeof(prog_info); 836 struct bpf_map_info map_info; 837 __u32 map_len = sizeof(map_info); 838 int err = 0; 839 840 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info, 841 &prog_len); 842 if (err) 843 return err; 844 845 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info, 846 &map_len); 847 if (err) { 848 hashmap__free(btf_prog_table); 849 return err; 850 } 851 852 return 0; 853 } 854 855 static void 856 show_btf_plain(struct bpf_btf_info *info, int fd, 857 struct hashmap *btf_prog_table, 858 struct hashmap *btf_map_table) 859 { 860 struct hashmap_entry *entry; 861 const char *name = u64_to_ptr(info->name); 862 int n; 863 864 printf("%u: ", info->id); 865 if (info->kernel_btf) 866 printf("name [%s] ", name); 867 else if (name && name[0]) 868 printf("name %s ", name); 869 else 870 printf("name <anon> "); 871 printf("size %uB", info->btf_size); 872 873 n = 0; 874 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) { 875 printf("%s%lu", n++ == 0 ? " prog_ids " : ",", entry->value); 876 } 877 878 n = 0; 879 hashmap__for_each_key_entry(btf_map_table, entry, info->id) { 880 printf("%s%lu", n++ == 0 ? " map_ids " : ",", entry->value); 881 } 882 883 emit_obj_refs_plain(refs_table, info->id, "\n\tpids "); 884 885 printf("\n"); 886 } 887 888 static void 889 show_btf_json(struct bpf_btf_info *info, int fd, 890 struct hashmap *btf_prog_table, 891 struct hashmap *btf_map_table) 892 { 893 struct hashmap_entry *entry; 894 const char *name = u64_to_ptr(info->name); 895 896 jsonw_start_object(json_wtr); /* btf object */ 897 jsonw_uint_field(json_wtr, "id", info->id); 898 jsonw_uint_field(json_wtr, "size", info->btf_size); 899 900 jsonw_name(json_wtr, "prog_ids"); 901 jsonw_start_array(json_wtr); /* prog_ids */ 902 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) { 903 jsonw_uint(json_wtr, entry->value); 904 } 905 jsonw_end_array(json_wtr); /* prog_ids */ 906 907 jsonw_name(json_wtr, "map_ids"); 908 jsonw_start_array(json_wtr); /* map_ids */ 909 hashmap__for_each_key_entry(btf_map_table, entry, info->id) { 910 jsonw_uint(json_wtr, entry->value); 911 } 912 jsonw_end_array(json_wtr); /* map_ids */ 913 914 emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */ 915 916 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf); 917 918 if (name && name[0]) 919 jsonw_string_field(json_wtr, "name", name); 920 921 jsonw_end_object(json_wtr); /* btf object */ 922 } 923 924 static int 925 show_btf(int fd, struct hashmap *btf_prog_table, 926 struct hashmap *btf_map_table) 927 { 928 struct bpf_btf_info info; 929 __u32 len = sizeof(info); 930 char name[64]; 931 int err; 932 933 memset(&info, 0, sizeof(info)); 934 err = bpf_obj_get_info_by_fd(fd, &info, &len); 935 if (err) { 936 p_err("can't get BTF object info: %s", strerror(errno)); 937 return -1; 938 } 939 /* if kernel support emitting BTF object name, pass name pointer */ 940 if (info.name_len) { 941 memset(&info, 0, sizeof(info)); 942 info.name_len = sizeof(name); 943 info.name = ptr_to_u64(name); 944 len = sizeof(info); 945 946 err = bpf_obj_get_info_by_fd(fd, &info, &len); 947 if (err) { 948 p_err("can't get BTF object info: %s", strerror(errno)); 949 return -1; 950 } 951 } 952 953 if (json_output) 954 show_btf_json(&info, fd, btf_prog_table, btf_map_table); 955 else 956 show_btf_plain(&info, fd, btf_prog_table, btf_map_table); 957 958 return 0; 959 } 960 961 static int do_show(int argc, char **argv) 962 { 963 struct hashmap *btf_prog_table; 964 struct hashmap *btf_map_table; 965 int err, fd = -1; 966 __u32 id = 0; 967 968 if (argc == 2) { 969 fd = btf_parse_fd(&argc, &argv); 970 if (fd < 0) 971 return -1; 972 } 973 974 if (argc) { 975 if (fd >= 0) 976 close(fd); 977 return BAD_ARG(); 978 } 979 980 btf_prog_table = hashmap__new(hash_fn_for_key_as_id, 981 equal_fn_for_key_as_id, NULL); 982 btf_map_table = hashmap__new(hash_fn_for_key_as_id, 983 equal_fn_for_key_as_id, NULL); 984 if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) { 985 hashmap__free(btf_prog_table); 986 hashmap__free(btf_map_table); 987 if (fd >= 0) 988 close(fd); 989 p_err("failed to create hashmap for object references"); 990 return -1; 991 } 992 err = build_btf_tables(btf_prog_table, btf_map_table); 993 if (err) { 994 if (fd >= 0) 995 close(fd); 996 return err; 997 } 998 build_obj_refs_table(&refs_table, BPF_OBJ_BTF); 999 1000 if (fd >= 0) { 1001 err = show_btf(fd, btf_prog_table, btf_map_table); 1002 close(fd); 1003 goto exit_free; 1004 } 1005 1006 if (json_output) 1007 jsonw_start_array(json_wtr); /* root array */ 1008 1009 while (true) { 1010 err = bpf_btf_get_next_id(id, &id); 1011 if (err) { 1012 if (errno == ENOENT) { 1013 err = 0; 1014 break; 1015 } 1016 p_err("can't get next BTF object: %s%s", 1017 strerror(errno), 1018 errno == EINVAL ? " -- kernel too old?" : ""); 1019 err = -1; 1020 break; 1021 } 1022 1023 fd = bpf_btf_get_fd_by_id(id); 1024 if (fd < 0) { 1025 if (errno == ENOENT) 1026 continue; 1027 p_err("can't get BTF object by id (%u): %s", 1028 id, strerror(errno)); 1029 err = -1; 1030 break; 1031 } 1032 1033 err = show_btf(fd, btf_prog_table, btf_map_table); 1034 close(fd); 1035 if (err) 1036 break; 1037 } 1038 1039 if (json_output) 1040 jsonw_end_array(json_wtr); /* root array */ 1041 1042 exit_free: 1043 hashmap__free(btf_prog_table); 1044 hashmap__free(btf_map_table); 1045 delete_obj_refs_table(refs_table); 1046 1047 return err; 1048 } 1049 1050 static int do_help(int argc, char **argv) 1051 { 1052 if (json_output) { 1053 jsonw_null(json_wtr); 1054 return 0; 1055 } 1056 1057 fprintf(stderr, 1058 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n" 1059 " %1$s %2$s dump BTF_SRC [format FORMAT]\n" 1060 " %1$s %2$s help\n" 1061 "\n" 1062 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n" 1063 " FORMAT := { raw | c }\n" 1064 " " HELP_SPEC_MAP "\n" 1065 " " HELP_SPEC_PROGRAM "\n" 1066 " " HELP_SPEC_OPTIONS " |\n" 1067 " {-B|--base-btf} }\n" 1068 "", 1069 bin_name, "btf"); 1070 1071 return 0; 1072 } 1073 1074 static const struct cmd cmds[] = { 1075 { "show", do_show }, 1076 { "list", do_show }, 1077 { "help", do_help }, 1078 { "dump", do_dump }, 1079 { 0 } 1080 }; 1081 1082 int do_btf(int argc, char **argv) 1083 { 1084 return cmd_select(cmds, argc, argv, do_help); 1085 } 1086