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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
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 [BTF_KIND_FLOAT] = "FLOAT",
40};
41
42struct btf_attach_table {
43 DECLARE_HASHTABLE(table, 16);
44};
45
46struct btf_attach_point {
47 __u32 obj_id;
48 __u32 btf_id;
49 struct hlist_node hash;
50};
51
52static const char *btf_int_enc_str(__u8 encoding)
53{
54 switch (encoding) {
55 case 0:
56 return "(none)";
57 case BTF_INT_SIGNED:
58 return "SIGNED";
59 case BTF_INT_CHAR:
60 return "CHAR";
61 case BTF_INT_BOOL:
62 return "BOOL";
63 default:
64 return "UNKN";
65 }
66}
67
68static const char *btf_var_linkage_str(__u32 linkage)
69{
70 switch (linkage) {
71 case BTF_VAR_STATIC:
72 return "static";
73 case BTF_VAR_GLOBAL_ALLOCATED:
74 return "global";
75 case BTF_VAR_GLOBAL_EXTERN:
76 return "extern";
77 default:
78 return "(unknown)";
79 }
80}
81
82static const char *btf_func_linkage_str(const struct btf_type *t)
83{
84 switch (btf_vlen(t)) {
85 case BTF_FUNC_STATIC:
86 return "static";
87 case BTF_FUNC_GLOBAL:
88 return "global";
89 case BTF_FUNC_EXTERN:
90 return "extern";
91 default:
92 return "(unknown)";
93 }
94}
95
96static const char *btf_str(const struct btf *btf, __u32 off)
97{
98 if (!off)
99 return "(anon)";
100 return btf__name_by_offset(btf, off) ? : "(invalid)";
101}
102
103static int btf_kind_safe(int kind)
104{
105 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
106}
107
108static int dump_btf_type(const struct btf *btf, __u32 id,
109 const struct btf_type *t)
110{
111 json_writer_t *w = json_wtr;
112 int kind = btf_kind(t);
113
114 if (json_output) {
115 jsonw_start_object(w);
116 jsonw_uint_field(w, "id", id);
117 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
118 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
119 } else {
120 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
121 btf_str(btf, t->name_off));
122 }
123
124 switch (kind) {
125 case BTF_KIND_INT: {
126 __u32 v = *(__u32 *)(t + 1);
127 const char *enc;
128
129 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
130
131 if (json_output) {
132 jsonw_uint_field(w, "size", t->size);
133 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
134 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
135 jsonw_string_field(w, "encoding", enc);
136 } else {
137 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
138 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
139 enc);
140 }
141 break;
142 }
143 case BTF_KIND_PTR:
144 case BTF_KIND_CONST:
145 case BTF_KIND_VOLATILE:
146 case BTF_KIND_RESTRICT:
147 case BTF_KIND_TYPEDEF:
148 if (json_output)
149 jsonw_uint_field(w, "type_id", t->type);
150 else
151 printf(" type_id=%u", t->type);
152 break;
153 case BTF_KIND_ARRAY: {
154 const struct btf_array *arr = (const void *)(t + 1);
155
156 if (json_output) {
157 jsonw_uint_field(w, "type_id", arr->type);
158 jsonw_uint_field(w, "index_type_id", arr->index_type);
159 jsonw_uint_field(w, "nr_elems", arr->nelems);
160 } else {
161 printf(" type_id=%u index_type_id=%u nr_elems=%u",
162 arr->type, arr->index_type, arr->nelems);
163 }
164 break;
165 }
166 case BTF_KIND_STRUCT:
167 case BTF_KIND_UNION: {
168 const struct btf_member *m = (const void *)(t + 1);
169 __u16 vlen = BTF_INFO_VLEN(t->info);
170 int i;
171
172 if (json_output) {
173 jsonw_uint_field(w, "size", t->size);
174 jsonw_uint_field(w, "vlen", vlen);
175 jsonw_name(w, "members");
176 jsonw_start_array(w);
177 } else {
178 printf(" size=%u vlen=%u", t->size, vlen);
179 }
180 for (i = 0; i < vlen; i++, m++) {
181 const char *name = btf_str(btf, m->name_off);
182 __u32 bit_off, bit_sz;
183
184 if (BTF_INFO_KFLAG(t->info)) {
185 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
186 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
187 } else {
188 bit_off = m->offset;
189 bit_sz = 0;
190 }
191
192 if (json_output) {
193 jsonw_start_object(w);
194 jsonw_string_field(w, "name", name);
195 jsonw_uint_field(w, "type_id", m->type);
196 jsonw_uint_field(w, "bits_offset", bit_off);
197 if (bit_sz) {
198 jsonw_uint_field(w, "bitfield_size",
199 bit_sz);
200 }
201 jsonw_end_object(w);
202 } else {
203 printf("\n\t'%s' type_id=%u bits_offset=%u",
204 name, m->type, bit_off);
205 if (bit_sz)
206 printf(" bitfield_size=%u", bit_sz);
207 }
208 }
209 if (json_output)
210 jsonw_end_array(w);
211 break;
212 }
213 case BTF_KIND_ENUM: {
214 const struct btf_enum *v = (const void *)(t + 1);
215 __u16 vlen = BTF_INFO_VLEN(t->info);
216 int i;
217
218 if (json_output) {
219 jsonw_uint_field(w, "size", t->size);
220 jsonw_uint_field(w, "vlen", vlen);
221 jsonw_name(w, "values");
222 jsonw_start_array(w);
223 } else {
224 printf(" size=%u vlen=%u", t->size, vlen);
225 }
226 for (i = 0; i < vlen; i++, v++) {
227 const char *name = btf_str(btf, v->name_off);
228
229 if (json_output) {
230 jsonw_start_object(w);
231 jsonw_string_field(w, "name", name);
232 jsonw_uint_field(w, "val", v->val);
233 jsonw_end_object(w);
234 } else {
235 printf("\n\t'%s' val=%u", name, v->val);
236 }
237 }
238 if (json_output)
239 jsonw_end_array(w);
240 break;
241 }
242 case BTF_KIND_FWD: {
243 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
244 : "struct";
245
246 if (json_output)
247 jsonw_string_field(w, "fwd_kind", fwd_kind);
248 else
249 printf(" fwd_kind=%s", fwd_kind);
250 break;
251 }
252 case BTF_KIND_FUNC: {
253 const char *linkage = btf_func_linkage_str(t);
254
255 if (json_output) {
256 jsonw_uint_field(w, "type_id", t->type);
257 jsonw_string_field(w, "linkage", linkage);
258 } else {
259 printf(" type_id=%u linkage=%s", t->type, linkage);
260 }
261 break;
262 }
263 case BTF_KIND_FUNC_PROTO: {
264 const struct btf_param *p = (const void *)(t + 1);
265 __u16 vlen = BTF_INFO_VLEN(t->info);
266 int i;
267
268 if (json_output) {
269 jsonw_uint_field(w, "ret_type_id", t->type);
270 jsonw_uint_field(w, "vlen", vlen);
271 jsonw_name(w, "params");
272 jsonw_start_array(w);
273 } else {
274 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
275 }
276 for (i = 0; i < vlen; i++, p++) {
277 const char *name = btf_str(btf, p->name_off);
278
279 if (json_output) {
280 jsonw_start_object(w);
281 jsonw_string_field(w, "name", name);
282 jsonw_uint_field(w, "type_id", p->type);
283 jsonw_end_object(w);
284 } else {
285 printf("\n\t'%s' type_id=%u", name, p->type);
286 }
287 }
288 if (json_output)
289 jsonw_end_array(w);
290 break;
291 }
292 case BTF_KIND_VAR: {
293 const struct btf_var *v = (const void *)(t + 1);
294 const char *linkage;
295
296 linkage = btf_var_linkage_str(v->linkage);
297
298 if (json_output) {
299 jsonw_uint_field(w, "type_id", t->type);
300 jsonw_string_field(w, "linkage", linkage);
301 } else {
302 printf(" type_id=%u, linkage=%s", t->type, linkage);
303 }
304 break;
305 }
306 case BTF_KIND_DATASEC: {
307 const struct btf_var_secinfo *v = (const void *)(t + 1);
308 const struct btf_type *vt;
309 __u16 vlen = BTF_INFO_VLEN(t->info);
310 int i;
311
312 if (json_output) {
313 jsonw_uint_field(w, "size", t->size);
314 jsonw_uint_field(w, "vlen", vlen);
315 jsonw_name(w, "vars");
316 jsonw_start_array(w);
317 } else {
318 printf(" size=%u vlen=%u", t->size, vlen);
319 }
320 for (i = 0; i < vlen; i++, v++) {
321 if (json_output) {
322 jsonw_start_object(w);
323 jsonw_uint_field(w, "type_id", v->type);
324 jsonw_uint_field(w, "offset", v->offset);
325 jsonw_uint_field(w, "size", v->size);
326 jsonw_end_object(w);
327 } else {
328 printf("\n\ttype_id=%u offset=%u size=%u",
329 v->type, v->offset, v->size);
330
331 if (v->type <= btf__get_nr_types(btf)) {
332 vt = btf__type_by_id(btf, v->type);
333 printf(" (%s '%s')",
334 btf_kind_str[btf_kind_safe(btf_kind(vt))],
335 btf_str(btf, vt->name_off));
336 }
337 }
338 }
339 if (json_output)
340 jsonw_end_array(w);
341 break;
342 }
343 case BTF_KIND_FLOAT: {
344 if (json_output)
345 jsonw_uint_field(w, "size", t->size);
346 else
347 printf(" size=%u", t->size);
348 break;
349 }
350 default:
351 break;
352 }
353
354 if (json_output)
355 jsonw_end_object(json_wtr);
356 else
357 printf("\n");
358
359 return 0;
360}
361
362static int dump_btf_raw(const struct btf *btf,
363 __u32 *root_type_ids, int root_type_cnt)
364{
365 const struct btf_type *t;
366 int i;
367
368 if (json_output) {
369 jsonw_start_object(json_wtr);
370 jsonw_name(json_wtr, "types");
371 jsonw_start_array(json_wtr);
372 }
373
374 if (root_type_cnt) {
375 for (i = 0; i < root_type_cnt; i++) {
376 t = btf__type_by_id(btf, root_type_ids[i]);
377 dump_btf_type(btf, root_type_ids[i], t);
378 }
379 } else {
380 const struct btf *base;
381 int cnt = btf__get_nr_types(btf);
382 int start_id = 1;
383
384 base = btf__base_btf(btf);
385 if (base)
386 start_id = btf__get_nr_types(base) + 1;
387
388 for (i = start_id; i <= cnt; i++) {
389 t = btf__type_by_id(btf, i);
390 dump_btf_type(btf, i, t);
391 }
392 }
393
394 if (json_output) {
395 jsonw_end_array(json_wtr);
396 jsonw_end_object(json_wtr);
397 }
398 return 0;
399}
400
401static void __printf(2, 0) btf_dump_printf(void *ctx,
402 const char *fmt, va_list args)
403{
404 vfprintf(stdout, fmt, args);
405}
406
407static int dump_btf_c(const struct btf *btf,
408 __u32 *root_type_ids, int root_type_cnt)
409{
410 struct btf_dump *d;
411 int err = 0, i;
412
413 d = btf_dump__new(btf, NULL, NULL, btf_dump_printf);
414 if (IS_ERR(d))
415 return PTR_ERR(d);
416
417 printf("#ifndef __VMLINUX_H__\n");
418 printf("#define __VMLINUX_H__\n");
419 printf("\n");
420 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
421 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
422 printf("#endif\n\n");
423
424 if (root_type_cnt) {
425 for (i = 0; i < root_type_cnt; i++) {
426 err = btf_dump__dump_type(d, root_type_ids[i]);
427 if (err)
428 goto done;
429 }
430 } else {
431 int cnt = btf__get_nr_types(btf);
432
433 for (i = 1; i <= cnt; i++) {
434 err = btf_dump__dump_type(d, i);
435 if (err)
436 goto done;
437 }
438 }
439
440 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
441 printf("#pragma clang attribute pop\n");
442 printf("#endif\n");
443 printf("\n");
444 printf("#endif /* __VMLINUX_H__ */\n");
445
446done:
447 btf_dump__free(d);
448 return err;
449}
450
451static int do_dump(int argc, char **argv)
452{
453 struct btf *btf = NULL, *base = NULL;
454 __u32 root_type_ids[2];
455 int root_type_cnt = 0;
456 bool dump_c = false;
457 __u32 btf_id = -1;
458 const char *src;
459 int fd = -1;
460 int err;
461
462 if (!REQ_ARGS(2)) {
463 usage();
464 return -1;
465 }
466 src = GET_ARG();
467 if (is_prefix(src, "map")) {
468 struct bpf_map_info info = {};
469 __u32 len = sizeof(info);
470
471 if (!REQ_ARGS(2)) {
472 usage();
473 return -1;
474 }
475
476 fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
477 if (fd < 0)
478 return -1;
479
480 btf_id = info.btf_id;
481 if (argc && is_prefix(*argv, "key")) {
482 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
483 NEXT_ARG();
484 } else if (argc && is_prefix(*argv, "value")) {
485 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
486 NEXT_ARG();
487 } else if (argc && is_prefix(*argv, "all")) {
488 NEXT_ARG();
489 } else if (argc && is_prefix(*argv, "kv")) {
490 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
491 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
492 NEXT_ARG();
493 } else {
494 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
495 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
496 }
497 } else if (is_prefix(src, "prog")) {
498 struct bpf_prog_info info = {};
499 __u32 len = sizeof(info);
500
501 if (!REQ_ARGS(2)) {
502 usage();
503 return -1;
504 }
505
506 fd = prog_parse_fd(&argc, &argv);
507 if (fd < 0)
508 return -1;
509
510 err = bpf_obj_get_info_by_fd(fd, &info, &len);
511 if (err) {
512 p_err("can't get prog info: %s", strerror(errno));
513 goto done;
514 }
515
516 btf_id = info.btf_id;
517 } else if (is_prefix(src, "id")) {
518 char *endptr;
519
520 btf_id = strtoul(*argv, &endptr, 0);
521 if (*endptr) {
522 p_err("can't parse %s as ID", *argv);
523 return -1;
524 }
525 NEXT_ARG();
526 } else if (is_prefix(src, "file")) {
527 const char sysfs_prefix[] = "/sys/kernel/btf/";
528 const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
529
530 if (!base_btf &&
531 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
532 strcmp(*argv, sysfs_vmlinux) != 0) {
533 base = btf__parse(sysfs_vmlinux, NULL);
534 if (libbpf_get_error(base)) {
535 p_err("failed to parse vmlinux BTF at '%s': %ld\n",
536 sysfs_vmlinux, libbpf_get_error(base));
537 base = NULL;
538 }
539 }
540
541 btf = btf__parse_split(*argv, base ?: base_btf);
542 if (IS_ERR(btf)) {
543 err = -PTR_ERR(btf);
544 btf = NULL;
545 p_err("failed to load BTF from %s: %s",
546 *argv, strerror(err));
547 goto done;
548 }
549 NEXT_ARG();
550 } else {
551 err = -1;
552 p_err("unrecognized BTF source specifier: '%s'", src);
553 goto done;
554 }
555
556 while (argc) {
557 if (is_prefix(*argv, "format")) {
558 NEXT_ARG();
559 if (argc < 1) {
560 p_err("expecting value for 'format' option\n");
561 err = -EINVAL;
562 goto done;
563 }
564 if (strcmp(*argv, "c") == 0) {
565 dump_c = true;
566 } else if (strcmp(*argv, "raw") == 0) {
567 dump_c = false;
568 } else {
569 p_err("unrecognized format specifier: '%s', possible values: raw, c",
570 *argv);
571 err = -EINVAL;
572 goto done;
573 }
574 NEXT_ARG();
575 } else {
576 p_err("unrecognized option: '%s'", *argv);
577 err = -EINVAL;
578 goto done;
579 }
580 }
581
582 if (!btf) {
583 err = btf__get_from_id(btf_id, &btf);
584 if (err) {
585 p_err("get btf by id (%u): %s", btf_id, strerror(err));
586 goto done;
587 }
588 if (!btf) {
589 err = -ENOENT;
590 p_err("can't find btf with ID (%u)", btf_id);
591 goto done;
592 }
593 }
594
595 if (dump_c) {
596 if (json_output) {
597 p_err("JSON output for C-syntax dump is not supported");
598 err = -ENOTSUP;
599 goto done;
600 }
601 err = dump_btf_c(btf, root_type_ids, root_type_cnt);
602 } else {
603 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
604 }
605
606done:
607 close(fd);
608 btf__free(btf);
609 btf__free(base);
610 return err;
611}
612
613static int btf_parse_fd(int *argc, char ***argv)
614{
615 unsigned int id;
616 char *endptr;
617 int fd;
618
619 if (!is_prefix(*argv[0], "id")) {
620 p_err("expected 'id', got: '%s'?", **argv);
621 return -1;
622 }
623 NEXT_ARGP();
624
625 id = strtoul(**argv, &endptr, 0);
626 if (*endptr) {
627 p_err("can't parse %s as ID", **argv);
628 return -1;
629 }
630 NEXT_ARGP();
631
632 fd = bpf_btf_get_fd_by_id(id);
633 if (fd < 0)
634 p_err("can't get BTF object by id (%u): %s",
635 id, strerror(errno));
636
637 return fd;
638}
639
640static void delete_btf_table(struct btf_attach_table *tab)
641{
642 struct btf_attach_point *obj;
643 struct hlist_node *tmp;
644
645 unsigned int bkt;
646
647 hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
648 hash_del(&obj->hash);
649 free(obj);
650 }
651}
652
653static int
654build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type,
655 void *info, __u32 *len)
656{
657 static const char * const names[] = {
658 [BPF_OBJ_UNKNOWN] = "unknown",
659 [BPF_OBJ_PROG] = "prog",
660 [BPF_OBJ_MAP] = "map",
661 };
662 struct btf_attach_point *obj_node;
663 __u32 btf_id, id = 0;
664 int err;
665 int fd;
666
667 while (true) {
668 switch (type) {
669 case BPF_OBJ_PROG:
670 err = bpf_prog_get_next_id(id, &id);
671 break;
672 case BPF_OBJ_MAP:
673 err = bpf_map_get_next_id(id, &id);
674 break;
675 default:
676 err = -1;
677 p_err("unexpected object type: %d", type);
678 goto err_free;
679 }
680 if (err) {
681 if (errno == ENOENT) {
682 err = 0;
683 break;
684 }
685 p_err("can't get next %s: %s%s", names[type],
686 strerror(errno),
687 errno == EINVAL ? " -- kernel too old?" : "");
688 goto err_free;
689 }
690
691 switch (type) {
692 case BPF_OBJ_PROG:
693 fd = bpf_prog_get_fd_by_id(id);
694 break;
695 case BPF_OBJ_MAP:
696 fd = bpf_map_get_fd_by_id(id);
697 break;
698 default:
699 err = -1;
700 p_err("unexpected object type: %d", type);
701 goto err_free;
702 }
703 if (fd < 0) {
704 if (errno == ENOENT)
705 continue;
706 p_err("can't get %s by id (%u): %s", names[type], id,
707 strerror(errno));
708 err = -1;
709 goto err_free;
710 }
711
712 memset(info, 0, *len);
713 err = bpf_obj_get_info_by_fd(fd, info, len);
714 close(fd);
715 if (err) {
716 p_err("can't get %s info: %s", names[type],
717 strerror(errno));
718 goto err_free;
719 }
720
721 switch (type) {
722 case BPF_OBJ_PROG:
723 btf_id = ((struct bpf_prog_info *)info)->btf_id;
724 break;
725 case BPF_OBJ_MAP:
726 btf_id = ((struct bpf_map_info *)info)->btf_id;
727 break;
728 default:
729 err = -1;
730 p_err("unexpected object type: %d", type);
731 goto err_free;
732 }
733 if (!btf_id)
734 continue;
735
736 obj_node = calloc(1, sizeof(*obj_node));
737 if (!obj_node) {
738 p_err("failed to allocate memory: %s", strerror(errno));
739 err = -ENOMEM;
740 goto err_free;
741 }
742
743 obj_node->obj_id = id;
744 obj_node->btf_id = btf_id;
745 hash_add(tab->table, &obj_node->hash, obj_node->btf_id);
746 }
747
748 return 0;
749
750err_free:
751 delete_btf_table(tab);
752 return err;
753}
754
755static int
756build_btf_tables(struct btf_attach_table *btf_prog_table,
757 struct btf_attach_table *btf_map_table)
758{
759 struct bpf_prog_info prog_info;
760 __u32 prog_len = sizeof(prog_info);
761 struct bpf_map_info map_info;
762 __u32 map_len = sizeof(map_info);
763 int err = 0;
764
765 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
766 &prog_len);
767 if (err)
768 return err;
769
770 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
771 &map_len);
772 if (err) {
773 delete_btf_table(btf_prog_table);
774 return err;
775 }
776
777 return 0;
778}
779
780static void
781show_btf_plain(struct bpf_btf_info *info, int fd,
782 struct btf_attach_table *btf_prog_table,
783 struct btf_attach_table *btf_map_table)
784{
785 struct btf_attach_point *obj;
786 const char *name = u64_to_ptr(info->name);
787 int n;
788
789 printf("%u: ", info->id);
790 if (info->kernel_btf)
791 printf("name [%s] ", name);
792 else if (name && name[0])
793 printf("name %s ", name);
794 else
795 printf("name <anon> ");
796 printf("size %uB", info->btf_size);
797
798 n = 0;
799 hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) {
800 if (obj->btf_id == info->id)
801 printf("%s%u", n++ == 0 ? " prog_ids " : ",",
802 obj->obj_id);
803 }
804
805 n = 0;
806 hash_for_each_possible(btf_map_table->table, obj, hash, info->id) {
807 if (obj->btf_id == info->id)
808 printf("%s%u", n++ == 0 ? " map_ids " : ",",
809 obj->obj_id);
810 }
811 emit_obj_refs_plain(&refs_table, info->id, "\n\tpids ");
812
813 printf("\n");
814}
815
816static void
817show_btf_json(struct bpf_btf_info *info, int fd,
818 struct btf_attach_table *btf_prog_table,
819 struct btf_attach_table *btf_map_table)
820{
821 struct btf_attach_point *obj;
822 const char *name = u64_to_ptr(info->name);
823
824 jsonw_start_object(json_wtr); /* btf object */
825 jsonw_uint_field(json_wtr, "id", info->id);
826 jsonw_uint_field(json_wtr, "size", info->btf_size);
827
828 jsonw_name(json_wtr, "prog_ids");
829 jsonw_start_array(json_wtr); /* prog_ids */
830 hash_for_each_possible(btf_prog_table->table, obj, hash,
831 info->id) {
832 if (obj->btf_id == info->id)
833 jsonw_uint(json_wtr, obj->obj_id);
834 }
835 jsonw_end_array(json_wtr); /* prog_ids */
836
837 jsonw_name(json_wtr, "map_ids");
838 jsonw_start_array(json_wtr); /* map_ids */
839 hash_for_each_possible(btf_map_table->table, obj, hash,
840 info->id) {
841 if (obj->btf_id == info->id)
842 jsonw_uint(json_wtr, obj->obj_id);
843 }
844 jsonw_end_array(json_wtr); /* map_ids */
845
846 emit_obj_refs_json(&refs_table, info->id, json_wtr); /* pids */
847
848 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
849
850 if (name && name[0])
851 jsonw_string_field(json_wtr, "name", name);
852
853 jsonw_end_object(json_wtr); /* btf object */
854}
855
856static int
857show_btf(int fd, struct btf_attach_table *btf_prog_table,
858 struct btf_attach_table *btf_map_table)
859{
860 struct bpf_btf_info info;
861 __u32 len = sizeof(info);
862 char name[64];
863 int err;
864
865 memset(&info, 0, sizeof(info));
866 err = bpf_obj_get_info_by_fd(fd, &info, &len);
867 if (err) {
868 p_err("can't get BTF object info: %s", strerror(errno));
869 return -1;
870 }
871 /* if kernel support emitting BTF object name, pass name pointer */
872 if (info.name_len) {
873 memset(&info, 0, sizeof(info));
874 info.name_len = sizeof(name);
875 info.name = ptr_to_u64(name);
876 len = sizeof(info);
877
878 err = bpf_obj_get_info_by_fd(fd, &info, &len);
879 if (err) {
880 p_err("can't get BTF object info: %s", strerror(errno));
881 return -1;
882 }
883 }
884
885 if (json_output)
886 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
887 else
888 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
889
890 return 0;
891}
892
893static int do_show(int argc, char **argv)
894{
895 struct btf_attach_table btf_prog_table;
896 struct btf_attach_table btf_map_table;
897 int err, fd = -1;
898 __u32 id = 0;
899
900 if (argc == 2) {
901 fd = btf_parse_fd(&argc, &argv);
902 if (fd < 0)
903 return -1;
904 }
905
906 if (argc) {
907 if (fd >= 0)
908 close(fd);
909 return BAD_ARG();
910 }
911
912 hash_init(btf_prog_table.table);
913 hash_init(btf_map_table.table);
914 err = build_btf_tables(&btf_prog_table, &btf_map_table);
915 if (err) {
916 if (fd >= 0)
917 close(fd);
918 return err;
919 }
920 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
921
922 if (fd >= 0) {
923 err = show_btf(fd, &btf_prog_table, &btf_map_table);
924 close(fd);
925 goto exit_free;
926 }
927
928 if (json_output)
929 jsonw_start_array(json_wtr); /* root array */
930
931 while (true) {
932 err = bpf_btf_get_next_id(id, &id);
933 if (err) {
934 if (errno == ENOENT) {
935 err = 0;
936 break;
937 }
938 p_err("can't get next BTF object: %s%s",
939 strerror(errno),
940 errno == EINVAL ? " -- kernel too old?" : "");
941 err = -1;
942 break;
943 }
944
945 fd = bpf_btf_get_fd_by_id(id);
946 if (fd < 0) {
947 if (errno == ENOENT)
948 continue;
949 p_err("can't get BTF object by id (%u): %s",
950 id, strerror(errno));
951 err = -1;
952 break;
953 }
954
955 err = show_btf(fd, &btf_prog_table, &btf_map_table);
956 close(fd);
957 if (err)
958 break;
959 }
960
961 if (json_output)
962 jsonw_end_array(json_wtr); /* root array */
963
964exit_free:
965 delete_btf_table(&btf_prog_table);
966 delete_btf_table(&btf_map_table);
967 delete_obj_refs_table(&refs_table);
968
969 return err;
970}
971
972static int do_help(int argc, char **argv)
973{
974 if (json_output) {
975 jsonw_null(json_wtr);
976 return 0;
977 }
978
979 fprintf(stderr,
980 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
981 " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
982 " %1$s %2$s help\n"
983 "\n"
984 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
985 " FORMAT := { raw | c }\n"
986 " " HELP_SPEC_MAP "\n"
987 " " HELP_SPEC_PROGRAM "\n"
988 " " HELP_SPEC_OPTIONS "\n"
989 "",
990 bin_name, "btf");
991
992 return 0;
993}
994
995static const struct cmd cmds[] = {
996 { "show", do_show },
997 { "list", do_show },
998 { "help", do_help },
999 { "dump", do_dump },
1000 { 0 }
1001};
1002
1003int do_btf(int argc, char **argv)
1004{
1005 return cmd_select(cmds, argc, argv, do_help);
1006}
1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2/* Copyright (C) 2019 Facebook */
3
4#ifndef _GNU_SOURCE
5#define _GNU_SOURCE
6#endif
7#include <errno.h>
8#include <fcntl.h>
9#include <linux/err.h>
10#include <stdbool.h>
11#include <stdio.h>
12#include <stdlib.h>
13#include <string.h>
14#include <unistd.h>
15#include <linux/btf.h>
16#include <sys/types.h>
17#include <sys/stat.h>
18
19#include <bpf/bpf.h>
20#include <bpf/btf.h>
21#include <bpf/hashmap.h>
22#include <bpf/libbpf.h>
23
24#include "json_writer.h"
25#include "main.h"
26
27#define KFUNC_DECL_TAG "bpf_kfunc"
28#define FASTCALL_DECL_TAG "bpf_fastcall"
29
30static const char * const btf_kind_str[NR_BTF_KINDS] = {
31 [BTF_KIND_UNKN] = "UNKNOWN",
32 [BTF_KIND_INT] = "INT",
33 [BTF_KIND_PTR] = "PTR",
34 [BTF_KIND_ARRAY] = "ARRAY",
35 [BTF_KIND_STRUCT] = "STRUCT",
36 [BTF_KIND_UNION] = "UNION",
37 [BTF_KIND_ENUM] = "ENUM",
38 [BTF_KIND_FWD] = "FWD",
39 [BTF_KIND_TYPEDEF] = "TYPEDEF",
40 [BTF_KIND_VOLATILE] = "VOLATILE",
41 [BTF_KIND_CONST] = "CONST",
42 [BTF_KIND_RESTRICT] = "RESTRICT",
43 [BTF_KIND_FUNC] = "FUNC",
44 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
45 [BTF_KIND_VAR] = "VAR",
46 [BTF_KIND_DATASEC] = "DATASEC",
47 [BTF_KIND_FLOAT] = "FLOAT",
48 [BTF_KIND_DECL_TAG] = "DECL_TAG",
49 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
50 [BTF_KIND_ENUM64] = "ENUM64",
51};
52
53struct sort_datum {
54 int index;
55 int type_rank;
56 const char *sort_name;
57 const char *own_name;
58 __u64 disambig_hash;
59};
60
61static const char *btf_int_enc_str(__u8 encoding)
62{
63 switch (encoding) {
64 case 0:
65 return "(none)";
66 case BTF_INT_SIGNED:
67 return "SIGNED";
68 case BTF_INT_CHAR:
69 return "CHAR";
70 case BTF_INT_BOOL:
71 return "BOOL";
72 default:
73 return "UNKN";
74 }
75}
76
77static const char *btf_var_linkage_str(__u32 linkage)
78{
79 switch (linkage) {
80 case BTF_VAR_STATIC:
81 return "static";
82 case BTF_VAR_GLOBAL_ALLOCATED:
83 return "global";
84 case BTF_VAR_GLOBAL_EXTERN:
85 return "extern";
86 default:
87 return "(unknown)";
88 }
89}
90
91static const char *btf_func_linkage_str(const struct btf_type *t)
92{
93 switch (btf_vlen(t)) {
94 case BTF_FUNC_STATIC:
95 return "static";
96 case BTF_FUNC_GLOBAL:
97 return "global";
98 case BTF_FUNC_EXTERN:
99 return "extern";
100 default:
101 return "(unknown)";
102 }
103}
104
105static const char *btf_str(const struct btf *btf, __u32 off)
106{
107 if (!off)
108 return "(anon)";
109 return btf__name_by_offset(btf, off) ? : "(invalid)";
110}
111
112static int btf_kind_safe(int kind)
113{
114 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
115}
116
117static int dump_btf_type(const struct btf *btf, __u32 id,
118 const struct btf_type *t)
119{
120 json_writer_t *w = json_wtr;
121 int kind = btf_kind(t);
122
123 if (json_output) {
124 jsonw_start_object(w);
125 jsonw_uint_field(w, "id", id);
126 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
127 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
128 } else {
129 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
130 btf_str(btf, t->name_off));
131 }
132
133 switch (kind) {
134 case BTF_KIND_INT: {
135 __u32 v = *(__u32 *)(t + 1);
136 const char *enc;
137
138 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
139
140 if (json_output) {
141 jsonw_uint_field(w, "size", t->size);
142 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
143 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
144 jsonw_string_field(w, "encoding", enc);
145 } else {
146 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
147 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
148 enc);
149 }
150 break;
151 }
152 case BTF_KIND_PTR:
153 case BTF_KIND_CONST:
154 case BTF_KIND_VOLATILE:
155 case BTF_KIND_RESTRICT:
156 case BTF_KIND_TYPEDEF:
157 case BTF_KIND_TYPE_TAG:
158 if (json_output)
159 jsonw_uint_field(w, "type_id", t->type);
160 else
161 printf(" type_id=%u", t->type);
162 break;
163 case BTF_KIND_ARRAY: {
164 const struct btf_array *arr = (const void *)(t + 1);
165
166 if (json_output) {
167 jsonw_uint_field(w, "type_id", arr->type);
168 jsonw_uint_field(w, "index_type_id", arr->index_type);
169 jsonw_uint_field(w, "nr_elems", arr->nelems);
170 } else {
171 printf(" type_id=%u index_type_id=%u nr_elems=%u",
172 arr->type, arr->index_type, arr->nelems);
173 }
174 break;
175 }
176 case BTF_KIND_STRUCT:
177 case BTF_KIND_UNION: {
178 const struct btf_member *m = (const void *)(t + 1);
179 __u16 vlen = BTF_INFO_VLEN(t->info);
180 int i;
181
182 if (json_output) {
183 jsonw_uint_field(w, "size", t->size);
184 jsonw_uint_field(w, "vlen", vlen);
185 jsonw_name(w, "members");
186 jsonw_start_array(w);
187 } else {
188 printf(" size=%u vlen=%u", t->size, vlen);
189 }
190 for (i = 0; i < vlen; i++, m++) {
191 const char *name = btf_str(btf, m->name_off);
192 __u32 bit_off, bit_sz;
193
194 if (BTF_INFO_KFLAG(t->info)) {
195 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
196 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
197 } else {
198 bit_off = m->offset;
199 bit_sz = 0;
200 }
201
202 if (json_output) {
203 jsonw_start_object(w);
204 jsonw_string_field(w, "name", name);
205 jsonw_uint_field(w, "type_id", m->type);
206 jsonw_uint_field(w, "bits_offset", bit_off);
207 if (bit_sz) {
208 jsonw_uint_field(w, "bitfield_size",
209 bit_sz);
210 }
211 jsonw_end_object(w);
212 } else {
213 printf("\n\t'%s' type_id=%u bits_offset=%u",
214 name, m->type, bit_off);
215 if (bit_sz)
216 printf(" bitfield_size=%u", bit_sz);
217 }
218 }
219 if (json_output)
220 jsonw_end_array(w);
221 break;
222 }
223 case BTF_KIND_ENUM: {
224 const struct btf_enum *v = (const void *)(t + 1);
225 __u16 vlen = BTF_INFO_VLEN(t->info);
226 const char *encoding;
227 int i;
228
229 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
230 if (json_output) {
231 jsonw_string_field(w, "encoding", encoding);
232 jsonw_uint_field(w, "size", t->size);
233 jsonw_uint_field(w, "vlen", vlen);
234 jsonw_name(w, "values");
235 jsonw_start_array(w);
236 } else {
237 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
238 }
239 for (i = 0; i < vlen; i++, v++) {
240 const char *name = btf_str(btf, v->name_off);
241
242 if (json_output) {
243 jsonw_start_object(w);
244 jsonw_string_field(w, "name", name);
245 if (btf_kflag(t))
246 jsonw_int_field(w, "val", v->val);
247 else
248 jsonw_uint_field(w, "val", v->val);
249 jsonw_end_object(w);
250 } else {
251 if (btf_kflag(t))
252 printf("\n\t'%s' val=%d", name, v->val);
253 else
254 printf("\n\t'%s' val=%u", name, v->val);
255 }
256 }
257 if (json_output)
258 jsonw_end_array(w);
259 break;
260 }
261 case BTF_KIND_ENUM64: {
262 const struct btf_enum64 *v = btf_enum64(t);
263 __u16 vlen = btf_vlen(t);
264 const char *encoding;
265 int i;
266
267 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
268 if (json_output) {
269 jsonw_string_field(w, "encoding", encoding);
270 jsonw_uint_field(w, "size", t->size);
271 jsonw_uint_field(w, "vlen", vlen);
272 jsonw_name(w, "values");
273 jsonw_start_array(w);
274 } else {
275 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
276 }
277 for (i = 0; i < vlen; i++, v++) {
278 const char *name = btf_str(btf, v->name_off);
279 __u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32;
280
281 if (json_output) {
282 jsonw_start_object(w);
283 jsonw_string_field(w, "name", name);
284 if (btf_kflag(t))
285 jsonw_int_field(w, "val", val);
286 else
287 jsonw_uint_field(w, "val", val);
288 jsonw_end_object(w);
289 } else {
290 if (btf_kflag(t))
291 printf("\n\t'%s' val=%lldLL", name,
292 (long long)val);
293 else
294 printf("\n\t'%s' val=%lluULL", name,
295 (unsigned long long)val);
296 }
297 }
298 if (json_output)
299 jsonw_end_array(w);
300 break;
301 }
302 case BTF_KIND_FWD: {
303 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
304 : "struct";
305
306 if (json_output)
307 jsonw_string_field(w, "fwd_kind", fwd_kind);
308 else
309 printf(" fwd_kind=%s", fwd_kind);
310 break;
311 }
312 case BTF_KIND_FUNC: {
313 const char *linkage = btf_func_linkage_str(t);
314
315 if (json_output) {
316 jsonw_uint_field(w, "type_id", t->type);
317 jsonw_string_field(w, "linkage", linkage);
318 } else {
319 printf(" type_id=%u linkage=%s", t->type, linkage);
320 }
321 break;
322 }
323 case BTF_KIND_FUNC_PROTO: {
324 const struct btf_param *p = (const void *)(t + 1);
325 __u16 vlen = BTF_INFO_VLEN(t->info);
326 int i;
327
328 if (json_output) {
329 jsonw_uint_field(w, "ret_type_id", t->type);
330 jsonw_uint_field(w, "vlen", vlen);
331 jsonw_name(w, "params");
332 jsonw_start_array(w);
333 } else {
334 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
335 }
336 for (i = 0; i < vlen; i++, p++) {
337 const char *name = btf_str(btf, p->name_off);
338
339 if (json_output) {
340 jsonw_start_object(w);
341 jsonw_string_field(w, "name", name);
342 jsonw_uint_field(w, "type_id", p->type);
343 jsonw_end_object(w);
344 } else {
345 printf("\n\t'%s' type_id=%u", name, p->type);
346 }
347 }
348 if (json_output)
349 jsonw_end_array(w);
350 break;
351 }
352 case BTF_KIND_VAR: {
353 const struct btf_var *v = (const void *)(t + 1);
354 const char *linkage;
355
356 linkage = btf_var_linkage_str(v->linkage);
357
358 if (json_output) {
359 jsonw_uint_field(w, "type_id", t->type);
360 jsonw_string_field(w, "linkage", linkage);
361 } else {
362 printf(" type_id=%u, linkage=%s", t->type, linkage);
363 }
364 break;
365 }
366 case BTF_KIND_DATASEC: {
367 const struct btf_var_secinfo *v = (const void *)(t + 1);
368 const struct btf_type *vt;
369 __u16 vlen = BTF_INFO_VLEN(t->info);
370 int i;
371
372 if (json_output) {
373 jsonw_uint_field(w, "size", t->size);
374 jsonw_uint_field(w, "vlen", vlen);
375 jsonw_name(w, "vars");
376 jsonw_start_array(w);
377 } else {
378 printf(" size=%u vlen=%u", t->size, vlen);
379 }
380 for (i = 0; i < vlen; i++, v++) {
381 if (json_output) {
382 jsonw_start_object(w);
383 jsonw_uint_field(w, "type_id", v->type);
384 jsonw_uint_field(w, "offset", v->offset);
385 jsonw_uint_field(w, "size", v->size);
386 jsonw_end_object(w);
387 } else {
388 printf("\n\ttype_id=%u offset=%u size=%u",
389 v->type, v->offset, v->size);
390
391 if (v->type < btf__type_cnt(btf)) {
392 vt = btf__type_by_id(btf, v->type);
393 printf(" (%s '%s')",
394 btf_kind_str[btf_kind_safe(btf_kind(vt))],
395 btf_str(btf, vt->name_off));
396 }
397 }
398 }
399 if (json_output)
400 jsonw_end_array(w);
401 break;
402 }
403 case BTF_KIND_FLOAT: {
404 if (json_output)
405 jsonw_uint_field(w, "size", t->size);
406 else
407 printf(" size=%u", t->size);
408 break;
409 }
410 case BTF_KIND_DECL_TAG: {
411 const struct btf_decl_tag *tag = (const void *)(t + 1);
412
413 if (json_output) {
414 jsonw_uint_field(w, "type_id", t->type);
415 jsonw_int_field(w, "component_idx", tag->component_idx);
416 } else {
417 printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
418 }
419 break;
420 }
421 default:
422 break;
423 }
424
425 if (json_output)
426 jsonw_end_object(json_wtr);
427 else
428 printf("\n");
429
430 return 0;
431}
432
433static int dump_btf_raw(const struct btf *btf,
434 __u32 *root_type_ids, int root_type_cnt)
435{
436 const struct btf_type *t;
437 int i;
438
439 if (json_output) {
440 jsonw_start_object(json_wtr);
441 jsonw_name(json_wtr, "types");
442 jsonw_start_array(json_wtr);
443 }
444
445 if (root_type_cnt) {
446 for (i = 0; i < root_type_cnt; i++) {
447 t = btf__type_by_id(btf, root_type_ids[i]);
448 dump_btf_type(btf, root_type_ids[i], t);
449 }
450 } else {
451 const struct btf *base;
452 int cnt = btf__type_cnt(btf);
453 int start_id = 1;
454
455 base = btf__base_btf(btf);
456 if (base)
457 start_id = btf__type_cnt(base);
458
459 for (i = start_id; i < cnt; i++) {
460 t = btf__type_by_id(btf, i);
461 dump_btf_type(btf, i, t);
462 }
463 }
464
465 if (json_output) {
466 jsonw_end_array(json_wtr);
467 jsonw_end_object(json_wtr);
468 }
469 return 0;
470}
471
472struct ptr_array {
473 __u32 cnt;
474 __u32 cap;
475 const void **elems;
476};
477
478static int ptr_array_push(const void *ptr, struct ptr_array *arr)
479{
480 __u32 new_cap;
481 void *tmp;
482
483 if (arr->cnt == arr->cap) {
484 new_cap = (arr->cap ?: 16) * 2;
485 tmp = realloc(arr->elems, sizeof(*arr->elems) * new_cap);
486 if (!tmp)
487 return -ENOMEM;
488 arr->elems = tmp;
489 arr->cap = new_cap;
490 }
491 arr->elems[arr->cnt++] = ptr;
492 return 0;
493}
494
495static void ptr_array_free(struct ptr_array *arr)
496{
497 free(arr->elems);
498}
499
500static int cmp_kfuncs(const void *pa, const void *pb, void *ctx)
501{
502 struct btf *btf = ctx;
503 const struct btf_type *a = *(void **)pa;
504 const struct btf_type *b = *(void **)pb;
505
506 return strcmp(btf__str_by_offset(btf, a->name_off),
507 btf__str_by_offset(btf, b->name_off));
508}
509
510static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf)
511{
512 LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts);
513 __u32 cnt = btf__type_cnt(btf), i, j;
514 struct ptr_array fastcalls = {};
515 struct ptr_array kfuncs = {};
516 int err = 0;
517
518 printf("\n/* BPF kfuncs */\n");
519 printf("#ifndef BPF_NO_KFUNC_PROTOTYPES\n");
520
521 for (i = 1; i < cnt; i++) {
522 const struct btf_type *t = btf__type_by_id(btf, i);
523 const struct btf_type *ft;
524 const char *name;
525
526 if (!btf_is_decl_tag(t))
527 continue;
528
529 if (btf_decl_tag(t)->component_idx != -1)
530 continue;
531
532 ft = btf__type_by_id(btf, t->type);
533 if (!btf_is_func(ft))
534 continue;
535
536 name = btf__name_by_offset(btf, t->name_off);
537 if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG)) == 0) {
538 err = ptr_array_push(ft, &kfuncs);
539 if (err)
540 goto out;
541 }
542
543 if (strncmp(name, FASTCALL_DECL_TAG, sizeof(FASTCALL_DECL_TAG)) == 0) {
544 err = ptr_array_push(ft, &fastcalls);
545 if (err)
546 goto out;
547 }
548 }
549
550 /* Sort kfuncs by name for improved vmlinux.h stability */
551 qsort_r(kfuncs.elems, kfuncs.cnt, sizeof(*kfuncs.elems), cmp_kfuncs, (void *)btf);
552 for (i = 0; i < kfuncs.cnt; i++) {
553 const struct btf_type *t = kfuncs.elems[i];
554
555 printf("extern ");
556
557 /* Assume small amount of fastcall kfuncs */
558 for (j = 0; j < fastcalls.cnt; j++) {
559 if (fastcalls.elems[j] == t) {
560 printf("__bpf_fastcall ");
561 break;
562 }
563 }
564
565 opts.field_name = btf__name_by_offset(btf, t->name_off);
566 err = btf_dump__emit_type_decl(d, t->type, &opts);
567 if (err)
568 goto out;
569
570 printf(" __weak __ksym;\n");
571 }
572
573 printf("#endif\n\n");
574
575out:
576 ptr_array_free(&fastcalls);
577 ptr_array_free(&kfuncs);
578 return err;
579}
580
581static void __printf(2, 0) btf_dump_printf(void *ctx,
582 const char *fmt, va_list args)
583{
584 vfprintf(stdout, fmt, args);
585}
586
587static int btf_type_rank(const struct btf *btf, __u32 index, bool has_name)
588{
589 const struct btf_type *t = btf__type_by_id(btf, index);
590 const int kind = btf_kind(t);
591 const int max_rank = 10;
592
593 if (t->name_off)
594 has_name = true;
595
596 switch (kind) {
597 case BTF_KIND_ENUM:
598 case BTF_KIND_ENUM64:
599 return has_name ? 1 : 0;
600 case BTF_KIND_INT:
601 case BTF_KIND_FLOAT:
602 return 2;
603 case BTF_KIND_STRUCT:
604 case BTF_KIND_UNION:
605 return has_name ? 3 : max_rank;
606 case BTF_KIND_FUNC_PROTO:
607 return has_name ? 4 : max_rank;
608 case BTF_KIND_ARRAY:
609 if (has_name)
610 return btf_type_rank(btf, btf_array(t)->type, has_name);
611 return max_rank;
612 case BTF_KIND_TYPE_TAG:
613 case BTF_KIND_CONST:
614 case BTF_KIND_PTR:
615 case BTF_KIND_VOLATILE:
616 case BTF_KIND_RESTRICT:
617 case BTF_KIND_TYPEDEF:
618 case BTF_KIND_DECL_TAG:
619 if (has_name)
620 return btf_type_rank(btf, t->type, has_name);
621 return max_rank;
622 default:
623 return max_rank;
624 }
625}
626
627static const char *btf_type_sort_name(const struct btf *btf, __u32 index, bool from_ref)
628{
629 const struct btf_type *t = btf__type_by_id(btf, index);
630
631 switch (btf_kind(t)) {
632 case BTF_KIND_ENUM:
633 case BTF_KIND_ENUM64: {
634 int name_off = t->name_off;
635
636 if (!from_ref && !name_off && btf_vlen(t))
637 name_off = btf_kind(t) == BTF_KIND_ENUM64 ?
638 btf_enum64(t)->name_off :
639 btf_enum(t)->name_off;
640
641 return btf__name_by_offset(btf, name_off);
642 }
643 case BTF_KIND_ARRAY:
644 return btf_type_sort_name(btf, btf_array(t)->type, true);
645 case BTF_KIND_TYPE_TAG:
646 case BTF_KIND_CONST:
647 case BTF_KIND_PTR:
648 case BTF_KIND_VOLATILE:
649 case BTF_KIND_RESTRICT:
650 case BTF_KIND_TYPEDEF:
651 case BTF_KIND_DECL_TAG:
652 return btf_type_sort_name(btf, t->type, true);
653 default:
654 return btf__name_by_offset(btf, t->name_off);
655 }
656 return NULL;
657}
658
659static __u64 hasher(__u64 hash, __u64 val)
660{
661 return hash * 31 + val;
662}
663
664static __u64 btf_name_hasher(__u64 hash, const struct btf *btf, __u32 name_off)
665{
666 if (!name_off)
667 return hash;
668
669 return hasher(hash, str_hash(btf__name_by_offset(btf, name_off)));
670}
671
672static __u64 btf_type_disambig_hash(const struct btf *btf, __u32 id, bool include_members)
673{
674 const struct btf_type *t = btf__type_by_id(btf, id);
675 int i;
676 size_t hash = 0;
677
678 hash = btf_name_hasher(hash, btf, t->name_off);
679
680 switch (btf_kind(t)) {
681 case BTF_KIND_ENUM:
682 case BTF_KIND_ENUM64:
683 for (i = 0; i < btf_vlen(t); i++) {
684 __u32 name_off = btf_is_enum(t) ?
685 btf_enum(t)[i].name_off :
686 btf_enum64(t)[i].name_off;
687
688 hash = btf_name_hasher(hash, btf, name_off);
689 }
690 break;
691 case BTF_KIND_STRUCT:
692 case BTF_KIND_UNION:
693 if (!include_members)
694 break;
695 for (i = 0; i < btf_vlen(t); i++) {
696 const struct btf_member *m = btf_members(t) + i;
697
698 hash = btf_name_hasher(hash, btf, m->name_off);
699 /* resolve field type's name and hash it as well */
700 hash = hasher(hash, btf_type_disambig_hash(btf, m->type, false));
701 }
702 break;
703 case BTF_KIND_TYPE_TAG:
704 case BTF_KIND_CONST:
705 case BTF_KIND_PTR:
706 case BTF_KIND_VOLATILE:
707 case BTF_KIND_RESTRICT:
708 case BTF_KIND_TYPEDEF:
709 case BTF_KIND_DECL_TAG:
710 hash = hasher(hash, btf_type_disambig_hash(btf, t->type, include_members));
711 break;
712 case BTF_KIND_ARRAY: {
713 struct btf_array *arr = btf_array(t);
714
715 hash = hasher(hash, arr->nelems);
716 hash = hasher(hash, btf_type_disambig_hash(btf, arr->type, include_members));
717 break;
718 }
719 default:
720 break;
721 }
722 return hash;
723}
724
725static int btf_type_compare(const void *left, const void *right)
726{
727 const struct sort_datum *d1 = (const struct sort_datum *)left;
728 const struct sort_datum *d2 = (const struct sort_datum *)right;
729 int r;
730
731 r = d1->type_rank - d2->type_rank;
732 r = r ?: strcmp(d1->sort_name, d2->sort_name);
733 r = r ?: strcmp(d1->own_name, d2->own_name);
734 if (r)
735 return r;
736
737 if (d1->disambig_hash != d2->disambig_hash)
738 return d1->disambig_hash < d2->disambig_hash ? -1 : 1;
739
740 return d1->index - d2->index;
741}
742
743static struct sort_datum *sort_btf_c(const struct btf *btf)
744{
745 struct sort_datum *datums;
746 int n;
747
748 n = btf__type_cnt(btf);
749 datums = malloc(sizeof(struct sort_datum) * n);
750 if (!datums)
751 return NULL;
752
753 for (int i = 0; i < n; ++i) {
754 struct sort_datum *d = datums + i;
755 const struct btf_type *t = btf__type_by_id(btf, i);
756
757 d->index = i;
758 d->type_rank = btf_type_rank(btf, i, false);
759 d->sort_name = btf_type_sort_name(btf, i, false);
760 d->own_name = btf__name_by_offset(btf, t->name_off);
761 d->disambig_hash = btf_type_disambig_hash(btf, i, true);
762 }
763
764 qsort(datums, n, sizeof(struct sort_datum), btf_type_compare);
765
766 return datums;
767}
768
769static int dump_btf_c(const struct btf *btf,
770 __u32 *root_type_ids, int root_type_cnt, bool sort_dump)
771{
772 struct sort_datum *datums = NULL;
773 struct btf_dump *d;
774 int err = 0, i;
775
776 d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
777 if (!d)
778 return -errno;
779
780 printf("#ifndef __VMLINUX_H__\n");
781 printf("#define __VMLINUX_H__\n");
782 printf("\n");
783 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
784 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
785 printf("#endif\n\n");
786 printf("#ifndef __ksym\n");
787 printf("#define __ksym __attribute__((section(\".ksyms\")))\n");
788 printf("#endif\n\n");
789 printf("#ifndef __weak\n");
790 printf("#define __weak __attribute__((weak))\n");
791 printf("#endif\n\n");
792 printf("#ifndef __bpf_fastcall\n");
793 printf("#if __has_attribute(bpf_fastcall)\n");
794 printf("#define __bpf_fastcall __attribute__((bpf_fastcall))\n");
795 printf("#else\n");
796 printf("#define __bpf_fastcall\n");
797 printf("#endif\n");
798 printf("#endif\n\n");
799
800 if (root_type_cnt) {
801 for (i = 0; i < root_type_cnt; i++) {
802 err = btf_dump__dump_type(d, root_type_ids[i]);
803 if (err)
804 goto done;
805 }
806 } else {
807 int cnt = btf__type_cnt(btf);
808
809 if (sort_dump)
810 datums = sort_btf_c(btf);
811 for (i = 1; i < cnt; i++) {
812 int idx = datums ? datums[i].index : i;
813
814 err = btf_dump__dump_type(d, idx);
815 if (err)
816 goto done;
817 }
818
819 err = dump_btf_kfuncs(d, btf);
820 if (err)
821 goto done;
822 }
823
824 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
825 printf("#pragma clang attribute pop\n");
826 printf("#endif\n");
827 printf("\n");
828 printf("#endif /* __VMLINUX_H__ */\n");
829
830done:
831 free(datums);
832 btf_dump__free(d);
833 return err;
834}
835
836static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
837
838static struct btf *get_vmlinux_btf_from_sysfs(void)
839{
840 struct btf *base;
841
842 base = btf__parse(sysfs_vmlinux, NULL);
843 if (!base)
844 p_err("failed to parse vmlinux BTF at '%s': %d\n",
845 sysfs_vmlinux, -errno);
846
847 return base;
848}
849
850#define BTF_NAME_BUFF_LEN 64
851
852static bool btf_is_kernel_module(__u32 btf_id)
853{
854 struct bpf_btf_info btf_info = {};
855 char btf_name[BTF_NAME_BUFF_LEN];
856 int btf_fd;
857 __u32 len;
858 int err;
859
860 btf_fd = bpf_btf_get_fd_by_id(btf_id);
861 if (btf_fd < 0) {
862 p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
863 return false;
864 }
865
866 len = sizeof(btf_info);
867 btf_info.name = ptr_to_u64(btf_name);
868 btf_info.name_len = sizeof(btf_name);
869 err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
870 close(btf_fd);
871 if (err) {
872 p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
873 return false;
874 }
875
876 return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
877}
878
879static int do_dump(int argc, char **argv)
880{
881 bool dump_c = false, sort_dump_c = true;
882 struct btf *btf = NULL, *base = NULL;
883 __u32 root_type_ids[2];
884 int root_type_cnt = 0;
885 __u32 btf_id = -1;
886 const char *src;
887 int fd = -1;
888 int err = 0;
889
890 if (!REQ_ARGS(2)) {
891 usage();
892 return -1;
893 }
894 src = GET_ARG();
895 if (is_prefix(src, "map")) {
896 struct bpf_map_info info = {};
897 __u32 len = sizeof(info);
898
899 if (!REQ_ARGS(2)) {
900 usage();
901 return -1;
902 }
903
904 fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
905 if (fd < 0)
906 return -1;
907
908 btf_id = info.btf_id;
909 if (argc && is_prefix(*argv, "key")) {
910 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
911 NEXT_ARG();
912 } else if (argc && is_prefix(*argv, "value")) {
913 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
914 NEXT_ARG();
915 } else if (argc && is_prefix(*argv, "all")) {
916 NEXT_ARG();
917 } else if (argc && is_prefix(*argv, "kv")) {
918 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
919 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
920 NEXT_ARG();
921 } else {
922 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
923 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
924 }
925 } else if (is_prefix(src, "prog")) {
926 struct bpf_prog_info info = {};
927 __u32 len = sizeof(info);
928
929 if (!REQ_ARGS(2)) {
930 usage();
931 return -1;
932 }
933
934 fd = prog_parse_fd(&argc, &argv);
935 if (fd < 0)
936 return -1;
937
938 err = bpf_prog_get_info_by_fd(fd, &info, &len);
939 if (err) {
940 p_err("can't get prog info: %s", strerror(errno));
941 goto done;
942 }
943
944 btf_id = info.btf_id;
945 } else if (is_prefix(src, "id")) {
946 char *endptr;
947
948 btf_id = strtoul(*argv, &endptr, 0);
949 if (*endptr) {
950 p_err("can't parse %s as ID", *argv);
951 return -1;
952 }
953 NEXT_ARG();
954 } else if (is_prefix(src, "file")) {
955 const char sysfs_prefix[] = "/sys/kernel/btf/";
956
957 if (!base_btf &&
958 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
959 strcmp(*argv, sysfs_vmlinux) != 0)
960 base = get_vmlinux_btf_from_sysfs();
961
962 btf = btf__parse_split(*argv, base ?: base_btf);
963 if (!btf) {
964 err = -errno;
965 p_err("failed to load BTF from %s: %s",
966 *argv, strerror(errno));
967 goto done;
968 }
969 NEXT_ARG();
970 } else {
971 err = -1;
972 p_err("unrecognized BTF source specifier: '%s'", src);
973 goto done;
974 }
975
976 while (argc) {
977 if (is_prefix(*argv, "format")) {
978 NEXT_ARG();
979 if (argc < 1) {
980 p_err("expecting value for 'format' option\n");
981 err = -EINVAL;
982 goto done;
983 }
984 if (strcmp(*argv, "c") == 0) {
985 dump_c = true;
986 } else if (strcmp(*argv, "raw") == 0) {
987 dump_c = false;
988 } else {
989 p_err("unrecognized format specifier: '%s', possible values: raw, c",
990 *argv);
991 err = -EINVAL;
992 goto done;
993 }
994 NEXT_ARG();
995 } else if (is_prefix(*argv, "unsorted")) {
996 sort_dump_c = false;
997 NEXT_ARG();
998 } else {
999 p_err("unrecognized option: '%s'", *argv);
1000 err = -EINVAL;
1001 goto done;
1002 }
1003 }
1004
1005 if (!btf) {
1006 if (!base_btf && btf_is_kernel_module(btf_id)) {
1007 p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
1008 sysfs_vmlinux);
1009 base_btf = get_vmlinux_btf_from_sysfs();
1010 }
1011
1012 btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
1013 if (!btf) {
1014 err = -errno;
1015 p_err("get btf by id (%u): %s", btf_id, strerror(errno));
1016 goto done;
1017 }
1018 }
1019
1020 if (dump_c) {
1021 if (json_output) {
1022 p_err("JSON output for C-syntax dump is not supported");
1023 err = -ENOTSUP;
1024 goto done;
1025 }
1026 err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c);
1027 } else {
1028 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
1029 }
1030
1031done:
1032 close(fd);
1033 btf__free(btf);
1034 btf__free(base);
1035 return err;
1036}
1037
1038static int btf_parse_fd(int *argc, char ***argv)
1039{
1040 unsigned int id;
1041 char *endptr;
1042 int fd;
1043
1044 if (!is_prefix(*argv[0], "id")) {
1045 p_err("expected 'id', got: '%s'?", **argv);
1046 return -1;
1047 }
1048 NEXT_ARGP();
1049
1050 id = strtoul(**argv, &endptr, 0);
1051 if (*endptr) {
1052 p_err("can't parse %s as ID", **argv);
1053 return -1;
1054 }
1055 NEXT_ARGP();
1056
1057 fd = bpf_btf_get_fd_by_id(id);
1058 if (fd < 0)
1059 p_err("can't get BTF object by id (%u): %s",
1060 id, strerror(errno));
1061
1062 return fd;
1063}
1064
1065static int
1066build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
1067 void *info, __u32 *len)
1068{
1069 static const char * const names[] = {
1070 [BPF_OBJ_UNKNOWN] = "unknown",
1071 [BPF_OBJ_PROG] = "prog",
1072 [BPF_OBJ_MAP] = "map",
1073 };
1074 __u32 btf_id, id = 0;
1075 int err;
1076 int fd;
1077
1078 while (true) {
1079 switch (type) {
1080 case BPF_OBJ_PROG:
1081 err = bpf_prog_get_next_id(id, &id);
1082 break;
1083 case BPF_OBJ_MAP:
1084 err = bpf_map_get_next_id(id, &id);
1085 break;
1086 default:
1087 err = -1;
1088 p_err("unexpected object type: %d", type);
1089 goto err_free;
1090 }
1091 if (err) {
1092 if (errno == ENOENT) {
1093 err = 0;
1094 break;
1095 }
1096 p_err("can't get next %s: %s%s", names[type],
1097 strerror(errno),
1098 errno == EINVAL ? " -- kernel too old?" : "");
1099 goto err_free;
1100 }
1101
1102 switch (type) {
1103 case BPF_OBJ_PROG:
1104 fd = bpf_prog_get_fd_by_id(id);
1105 break;
1106 case BPF_OBJ_MAP:
1107 fd = bpf_map_get_fd_by_id(id);
1108 break;
1109 default:
1110 err = -1;
1111 p_err("unexpected object type: %d", type);
1112 goto err_free;
1113 }
1114 if (fd < 0) {
1115 if (errno == ENOENT)
1116 continue;
1117 p_err("can't get %s by id (%u): %s", names[type], id,
1118 strerror(errno));
1119 err = -1;
1120 goto err_free;
1121 }
1122
1123 memset(info, 0, *len);
1124 if (type == BPF_OBJ_PROG)
1125 err = bpf_prog_get_info_by_fd(fd, info, len);
1126 else
1127 err = bpf_map_get_info_by_fd(fd, info, len);
1128 close(fd);
1129 if (err) {
1130 p_err("can't get %s info: %s", names[type],
1131 strerror(errno));
1132 goto err_free;
1133 }
1134
1135 switch (type) {
1136 case BPF_OBJ_PROG:
1137 btf_id = ((struct bpf_prog_info *)info)->btf_id;
1138 break;
1139 case BPF_OBJ_MAP:
1140 btf_id = ((struct bpf_map_info *)info)->btf_id;
1141 break;
1142 default:
1143 err = -1;
1144 p_err("unexpected object type: %d", type);
1145 goto err_free;
1146 }
1147 if (!btf_id)
1148 continue;
1149
1150 err = hashmap__append(tab, btf_id, id);
1151 if (err) {
1152 p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
1153 btf_id, id, strerror(-err));
1154 goto err_free;
1155 }
1156 }
1157
1158 return 0;
1159
1160err_free:
1161 hashmap__free(tab);
1162 return err;
1163}
1164
1165static int
1166build_btf_tables(struct hashmap *btf_prog_table,
1167 struct hashmap *btf_map_table)
1168{
1169 struct bpf_prog_info prog_info;
1170 __u32 prog_len = sizeof(prog_info);
1171 struct bpf_map_info map_info;
1172 __u32 map_len = sizeof(map_info);
1173 int err = 0;
1174
1175 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
1176 &prog_len);
1177 if (err)
1178 return err;
1179
1180 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
1181 &map_len);
1182 if (err) {
1183 hashmap__free(btf_prog_table);
1184 return err;
1185 }
1186
1187 return 0;
1188}
1189
1190static void
1191show_btf_plain(struct bpf_btf_info *info, int fd,
1192 struct hashmap *btf_prog_table,
1193 struct hashmap *btf_map_table)
1194{
1195 struct hashmap_entry *entry;
1196 const char *name = u64_to_ptr(info->name);
1197 int n;
1198
1199 printf("%u: ", info->id);
1200 if (info->kernel_btf)
1201 printf("name [%s] ", name);
1202 else if (name && name[0])
1203 printf("name %s ", name);
1204 else
1205 printf("name <anon> ");
1206 printf("size %uB", info->btf_size);
1207
1208 n = 0;
1209 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1210 printf("%s%lu", n++ == 0 ? " prog_ids " : ",", entry->value);
1211 }
1212
1213 n = 0;
1214 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1215 printf("%s%lu", n++ == 0 ? " map_ids " : ",", entry->value);
1216 }
1217
1218 emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
1219
1220 printf("\n");
1221}
1222
1223static void
1224show_btf_json(struct bpf_btf_info *info, int fd,
1225 struct hashmap *btf_prog_table,
1226 struct hashmap *btf_map_table)
1227{
1228 struct hashmap_entry *entry;
1229 const char *name = u64_to_ptr(info->name);
1230
1231 jsonw_start_object(json_wtr); /* btf object */
1232 jsonw_uint_field(json_wtr, "id", info->id);
1233 jsonw_uint_field(json_wtr, "size", info->btf_size);
1234
1235 jsonw_name(json_wtr, "prog_ids");
1236 jsonw_start_array(json_wtr); /* prog_ids */
1237 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1238 jsonw_uint(json_wtr, entry->value);
1239 }
1240 jsonw_end_array(json_wtr); /* prog_ids */
1241
1242 jsonw_name(json_wtr, "map_ids");
1243 jsonw_start_array(json_wtr); /* map_ids */
1244 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1245 jsonw_uint(json_wtr, entry->value);
1246 }
1247 jsonw_end_array(json_wtr); /* map_ids */
1248
1249 emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */
1250
1251 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
1252
1253 if (name && name[0])
1254 jsonw_string_field(json_wtr, "name", name);
1255
1256 jsonw_end_object(json_wtr); /* btf object */
1257}
1258
1259static int
1260show_btf(int fd, struct hashmap *btf_prog_table,
1261 struct hashmap *btf_map_table)
1262{
1263 struct bpf_btf_info info;
1264 __u32 len = sizeof(info);
1265 char name[64];
1266 int err;
1267
1268 memset(&info, 0, sizeof(info));
1269 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1270 if (err) {
1271 p_err("can't get BTF object info: %s", strerror(errno));
1272 return -1;
1273 }
1274 /* if kernel support emitting BTF object name, pass name pointer */
1275 if (info.name_len) {
1276 memset(&info, 0, sizeof(info));
1277 info.name_len = sizeof(name);
1278 info.name = ptr_to_u64(name);
1279 len = sizeof(info);
1280
1281 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1282 if (err) {
1283 p_err("can't get BTF object info: %s", strerror(errno));
1284 return -1;
1285 }
1286 }
1287
1288 if (json_output)
1289 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
1290 else
1291 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
1292
1293 return 0;
1294}
1295
1296static int do_show(int argc, char **argv)
1297{
1298 struct hashmap *btf_prog_table;
1299 struct hashmap *btf_map_table;
1300 int err, fd = -1;
1301 __u32 id = 0;
1302
1303 if (argc == 2) {
1304 fd = btf_parse_fd(&argc, &argv);
1305 if (fd < 0)
1306 return -1;
1307 }
1308
1309 if (argc) {
1310 if (fd >= 0)
1311 close(fd);
1312 return BAD_ARG();
1313 }
1314
1315 btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
1316 equal_fn_for_key_as_id, NULL);
1317 btf_map_table = hashmap__new(hash_fn_for_key_as_id,
1318 equal_fn_for_key_as_id, NULL);
1319 if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
1320 hashmap__free(btf_prog_table);
1321 hashmap__free(btf_map_table);
1322 if (fd >= 0)
1323 close(fd);
1324 p_err("failed to create hashmap for object references");
1325 return -1;
1326 }
1327 err = build_btf_tables(btf_prog_table, btf_map_table);
1328 if (err) {
1329 if (fd >= 0)
1330 close(fd);
1331 return err;
1332 }
1333 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
1334
1335 if (fd >= 0) {
1336 err = show_btf(fd, btf_prog_table, btf_map_table);
1337 close(fd);
1338 goto exit_free;
1339 }
1340
1341 if (json_output)
1342 jsonw_start_array(json_wtr); /* root array */
1343
1344 while (true) {
1345 err = bpf_btf_get_next_id(id, &id);
1346 if (err) {
1347 if (errno == ENOENT) {
1348 err = 0;
1349 break;
1350 }
1351 p_err("can't get next BTF object: %s%s",
1352 strerror(errno),
1353 errno == EINVAL ? " -- kernel too old?" : "");
1354 err = -1;
1355 break;
1356 }
1357
1358 fd = bpf_btf_get_fd_by_id(id);
1359 if (fd < 0) {
1360 if (errno == ENOENT)
1361 continue;
1362 p_err("can't get BTF object by id (%u): %s",
1363 id, strerror(errno));
1364 err = -1;
1365 break;
1366 }
1367
1368 err = show_btf(fd, btf_prog_table, btf_map_table);
1369 close(fd);
1370 if (err)
1371 break;
1372 }
1373
1374 if (json_output)
1375 jsonw_end_array(json_wtr); /* root array */
1376
1377exit_free:
1378 hashmap__free(btf_prog_table);
1379 hashmap__free(btf_map_table);
1380 delete_obj_refs_table(refs_table);
1381
1382 return err;
1383}
1384
1385static int do_help(int argc, char **argv)
1386{
1387 if (json_output) {
1388 jsonw_null(json_wtr);
1389 return 0;
1390 }
1391
1392 fprintf(stderr,
1393 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
1394 " %1$s %2$s dump BTF_SRC [format FORMAT]\n"
1395 " %1$s %2$s help\n"
1396 "\n"
1397 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
1398 " FORMAT := { raw | c [unsorted] }\n"
1399 " " HELP_SPEC_MAP "\n"
1400 " " HELP_SPEC_PROGRAM "\n"
1401 " " HELP_SPEC_OPTIONS " |\n"
1402 " {-B|--base-btf} }\n"
1403 "",
1404 bin_name, "btf");
1405
1406 return 0;
1407}
1408
1409static const struct cmd cmds[] = {
1410 { "show", do_show },
1411 { "list", do_show },
1412 { "help", do_help },
1413 { "dump", do_dump },
1414 { 0 }
1415};
1416
1417int do_btf(int argc, char **argv)
1418{
1419 return cmd_select(cmds, argc, argv, do_help);
1420}