1
2
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
22static 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
41struct btf_attach_table {
42 DECLARE_HASHTABLE(table, 16);
43};
44
45struct btf_attach_point {
46 __u32 obj_id;
47 __u32 btf_id;
48 struct hlist_node hash;
49};
50
51static 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
67static 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
79static 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
93static 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
100static 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
342static 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
375static void __printf(2, 0) btf_dump_printf(void *ctx,
376 const char *fmt, va_list args)
377{
378 vfprintf(stdout, fmt, args);
379}
380
381static 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
420done:
421 btf_dump__free(d);
422 return err;
423}
424
425static 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
564done:
565 close(fd);
566 btf__free(btf);
567 return err;
568}
569
570static 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
597static 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
610static int
611build_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
706err_free:
707 delete_btf_table(tab);
708 return err;
709}
710
711static int
712build_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
736static void
737show_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
765static void
766show_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);
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);
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);
784
785 jsonw_name(json_wtr, "map_ids");
786 jsonw_start_array(json_wtr);
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);
793
794 emit_obj_refs_json(&refs_table, info->id, json_wtr);
795
796 jsonw_end_object(json_wtr);
797}
798
799static int
800show_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
821static 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);
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);
891
892exit_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
900static 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
923static const struct cmd cmds[] = {
924 { "show", do_show },
925 { "list", do_show },
926 { "help", do_help },
927 { "dump", do_dump },
928 { 0 }
929};
930
931int do_btf(int argc, char **argv)
932{
933 return cmd_select(cmds, argc, argv, do_help);
934}
935
