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
30 #define MAX_ROOT_IDS 16
31
32 static const char * const btf_kind_str[NR_BTF_KINDS] = {
33 [BTF_KIND_UNKN] = "UNKNOWN",
34 [BTF_KIND_INT] = "INT",
35 [BTF_KIND_PTR] = "PTR",
36 [BTF_KIND_ARRAY] = "ARRAY",
37 [BTF_KIND_STRUCT] = "STRUCT",
38 [BTF_KIND_UNION] = "UNION",
39 [BTF_KIND_ENUM] = "ENUM",
40 [BTF_KIND_FWD] = "FWD",
41 [BTF_KIND_TYPEDEF] = "TYPEDEF",
42 [BTF_KIND_VOLATILE] = "VOLATILE",
43 [BTF_KIND_CONST] = "CONST",
44 [BTF_KIND_RESTRICT] = "RESTRICT",
45 [BTF_KIND_FUNC] = "FUNC",
46 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
47 [BTF_KIND_VAR] = "VAR",
48 [BTF_KIND_DATASEC] = "DATASEC",
49 [BTF_KIND_FLOAT] = "FLOAT",
50 [BTF_KIND_DECL_TAG] = "DECL_TAG",
51 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
52 [BTF_KIND_ENUM64] = "ENUM64",
53 };
54
55 struct sort_datum {
56 int index;
57 int type_rank;
58 const char *sort_name;
59 const char *own_name;
60 __u64 disambig_hash;
61 };
62
btf_int_enc_str(__u8 encoding)63 static const char *btf_int_enc_str(__u8 encoding)
64 {
65 switch (encoding) {
66 case 0:
67 return "(none)";
68 case BTF_INT_SIGNED:
69 return "SIGNED";
70 case BTF_INT_CHAR:
71 return "CHAR";
72 case BTF_INT_BOOL:
73 return "BOOL";
74 default:
75 return "UNKN";
76 }
77 }
78
btf_var_linkage_str(__u32 linkage)79 static const char *btf_var_linkage_str(__u32 linkage)
80 {
81 switch (linkage) {
82 case BTF_VAR_STATIC:
83 return "static";
84 case BTF_VAR_GLOBAL_ALLOCATED:
85 return "global";
86 case BTF_VAR_GLOBAL_EXTERN:
87 return "extern";
88 default:
89 return "(unknown)";
90 }
91 }
92
btf_func_linkage_str(const struct btf_type * t)93 static const char *btf_func_linkage_str(const struct btf_type *t)
94 {
95 switch (btf_vlen(t)) {
96 case BTF_FUNC_STATIC:
97 return "static";
98 case BTF_FUNC_GLOBAL:
99 return "global";
100 case BTF_FUNC_EXTERN:
101 return "extern";
102 default:
103 return "(unknown)";
104 }
105 }
106
btf_str(const struct btf * btf,__u32 off)107 static const char *btf_str(const struct btf *btf, __u32 off)
108 {
109 if (!off)
110 return "(anon)";
111 return btf__name_by_offset(btf, off) ? : "(invalid)";
112 }
113
btf_kind_safe(int kind)114 static int btf_kind_safe(int kind)
115 {
116 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
117 }
118
dump_btf_type(const struct btf * btf,__u32 id,const struct btf_type * t)119 static int dump_btf_type(const struct btf *btf, __u32 id,
120 const struct btf_type *t)
121 {
122 json_writer_t *w = json_wtr;
123 int kind = btf_kind(t);
124
125 if (json_output) {
126 jsonw_start_object(w);
127 jsonw_uint_field(w, "id", id);
128 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
129 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
130 } else {
131 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
132 btf_str(btf, t->name_off));
133 }
134
135 switch (kind) {
136 case BTF_KIND_INT: {
137 __u32 v = *(__u32 *)(t + 1);
138 const char *enc;
139
140 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
141
142 if (json_output) {
143 jsonw_uint_field(w, "size", t->size);
144 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
145 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
146 jsonw_string_field(w, "encoding", enc);
147 } else {
148 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
149 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
150 enc);
151 }
152 break;
153 }
154 case BTF_KIND_PTR:
155 case BTF_KIND_CONST:
156 case BTF_KIND_VOLATILE:
157 case BTF_KIND_RESTRICT:
158 case BTF_KIND_TYPEDEF:
159 case BTF_KIND_TYPE_TAG:
160 if (json_output)
161 jsonw_uint_field(w, "type_id", t->type);
162 else
163 printf(" type_id=%u", t->type);
164 break;
165 case BTF_KIND_ARRAY: {
166 const struct btf_array *arr = (const void *)(t + 1);
167
168 if (json_output) {
169 jsonw_uint_field(w, "type_id", arr->type);
170 jsonw_uint_field(w, "index_type_id", arr->index_type);
171 jsonw_uint_field(w, "nr_elems", arr->nelems);
172 } else {
173 printf(" type_id=%u index_type_id=%u nr_elems=%u",
174 arr->type, arr->index_type, arr->nelems);
175 }
176 break;
177 }
178 case BTF_KIND_STRUCT:
179 case BTF_KIND_UNION: {
180 const struct btf_member *m = (const void *)(t + 1);
181 __u16 vlen = BTF_INFO_VLEN(t->info);
182 int i;
183
184 if (json_output) {
185 jsonw_uint_field(w, "size", t->size);
186 jsonw_uint_field(w, "vlen", vlen);
187 jsonw_name(w, "members");
188 jsonw_start_array(w);
189 } else {
190 printf(" size=%u vlen=%u", t->size, vlen);
191 }
192 for (i = 0; i < vlen; i++, m++) {
193 const char *name = btf_str(btf, m->name_off);
194 __u32 bit_off, bit_sz;
195
196 if (BTF_INFO_KFLAG(t->info)) {
197 bit_off = BTF_MEMBER_BIT_OFFSET(m->offset);
198 bit_sz = BTF_MEMBER_BITFIELD_SIZE(m->offset);
199 } else {
200 bit_off = m->offset;
201 bit_sz = 0;
202 }
203
204 if (json_output) {
205 jsonw_start_object(w);
206 jsonw_string_field(w, "name", name);
207 jsonw_uint_field(w, "type_id", m->type);
208 jsonw_uint_field(w, "bits_offset", bit_off);
209 if (bit_sz) {
210 jsonw_uint_field(w, "bitfield_size",
211 bit_sz);
212 }
213 jsonw_end_object(w);
214 } else {
215 printf("\n\t'%s' type_id=%u bits_offset=%u",
216 name, m->type, bit_off);
217 if (bit_sz)
218 printf(" bitfield_size=%u", bit_sz);
219 }
220 }
221 if (json_output)
222 jsonw_end_array(w);
223 break;
224 }
225 case BTF_KIND_ENUM: {
226 const struct btf_enum *v = (const void *)(t + 1);
227 __u16 vlen = BTF_INFO_VLEN(t->info);
228 const char *encoding;
229 int i;
230
231 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
232 if (json_output) {
233 jsonw_string_field(w, "encoding", encoding);
234 jsonw_uint_field(w, "size", t->size);
235 jsonw_uint_field(w, "vlen", vlen);
236 jsonw_name(w, "values");
237 jsonw_start_array(w);
238 } else {
239 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
240 }
241 for (i = 0; i < vlen; i++, v++) {
242 const char *name = btf_str(btf, v->name_off);
243
244 if (json_output) {
245 jsonw_start_object(w);
246 jsonw_string_field(w, "name", name);
247 if (btf_kflag(t))
248 jsonw_int_field(w, "val", v->val);
249 else
250 jsonw_uint_field(w, "val", v->val);
251 jsonw_end_object(w);
252 } else {
253 if (btf_kflag(t))
254 printf("\n\t'%s' val=%d", name, v->val);
255 else
256 printf("\n\t'%s' val=%u", name, v->val);
257 }
258 }
259 if (json_output)
260 jsonw_end_array(w);
261 break;
262 }
263 case BTF_KIND_ENUM64: {
264 const struct btf_enum64 *v = btf_enum64(t);
265 __u16 vlen = btf_vlen(t);
266 const char *encoding;
267 int i;
268
269 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
270 if (json_output) {
271 jsonw_string_field(w, "encoding", encoding);
272 jsonw_uint_field(w, "size", t->size);
273 jsonw_uint_field(w, "vlen", vlen);
274 jsonw_name(w, "values");
275 jsonw_start_array(w);
276 } else {
277 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
278 }
279 for (i = 0; i < vlen; i++, v++) {
280 const char *name = btf_str(btf, v->name_off);
281 __u64 val = ((__u64)v->val_hi32 << 32) | v->val_lo32;
282
283 if (json_output) {
284 jsonw_start_object(w);
285 jsonw_string_field(w, "name", name);
286 if (btf_kflag(t))
287 jsonw_int_field(w, "val", val);
288 else
289 jsonw_uint_field(w, "val", val);
290 jsonw_end_object(w);
291 } else {
292 if (btf_kflag(t))
293 printf("\n\t'%s' val=%lldLL", name,
294 (long long)val);
295 else
296 printf("\n\t'%s' val=%lluULL", name,
297 (unsigned long long)val);
298 }
299 }
300 if (json_output)
301 jsonw_end_array(w);
302 break;
303 }
304 case BTF_KIND_FWD: {
305 const char *fwd_kind = BTF_INFO_KFLAG(t->info) ? "union"
306 : "struct";
307
308 if (json_output)
309 jsonw_string_field(w, "fwd_kind", fwd_kind);
310 else
311 printf(" fwd_kind=%s", fwd_kind);
312 break;
313 }
314 case BTF_KIND_FUNC: {
315 const char *linkage = btf_func_linkage_str(t);
316
317 if (json_output) {
318 jsonw_uint_field(w, "type_id", t->type);
319 jsonw_string_field(w, "linkage", linkage);
320 } else {
321 printf(" type_id=%u linkage=%s", t->type, linkage);
322 }
323 break;
324 }
325 case BTF_KIND_FUNC_PROTO: {
326 const struct btf_param *p = (const void *)(t + 1);
327 __u16 vlen = BTF_INFO_VLEN(t->info);
328 int i;
329
330 if (json_output) {
331 jsonw_uint_field(w, "ret_type_id", t->type);
332 jsonw_uint_field(w, "vlen", vlen);
333 jsonw_name(w, "params");
334 jsonw_start_array(w);
335 } else {
336 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
337 }
338 for (i = 0; i < vlen; i++, p++) {
339 const char *name = btf_str(btf, p->name_off);
340
341 if (json_output) {
342 jsonw_start_object(w);
343 jsonw_string_field(w, "name", name);
344 jsonw_uint_field(w, "type_id", p->type);
345 jsonw_end_object(w);
346 } else {
347 printf("\n\t'%s' type_id=%u", name, p->type);
348 }
349 }
350 if (json_output)
351 jsonw_end_array(w);
352 break;
353 }
354 case BTF_KIND_VAR: {
355 const struct btf_var *v = (const void *)(t + 1);
356 const char *linkage;
357
358 linkage = btf_var_linkage_str(v->linkage);
359
360 if (json_output) {
361 jsonw_uint_field(w, "type_id", t->type);
362 jsonw_string_field(w, "linkage", linkage);
363 } else {
364 printf(" type_id=%u, linkage=%s", t->type, linkage);
365 }
366 break;
367 }
368 case BTF_KIND_DATASEC: {
369 const struct btf_var_secinfo *v = (const void *)(t + 1);
370 const struct btf_type *vt;
371 __u16 vlen = BTF_INFO_VLEN(t->info);
372 int i;
373
374 if (json_output) {
375 jsonw_uint_field(w, "size", t->size);
376 jsonw_uint_field(w, "vlen", vlen);
377 jsonw_name(w, "vars");
378 jsonw_start_array(w);
379 } else {
380 printf(" size=%u vlen=%u", t->size, vlen);
381 }
382 for (i = 0; i < vlen; i++, v++) {
383 if (json_output) {
384 jsonw_start_object(w);
385 jsonw_uint_field(w, "type_id", v->type);
386 jsonw_uint_field(w, "offset", v->offset);
387 jsonw_uint_field(w, "size", v->size);
388 jsonw_end_object(w);
389 } else {
390 printf("\n\ttype_id=%u offset=%u size=%u",
391 v->type, v->offset, v->size);
392
393 if (v->type < btf__type_cnt(btf)) {
394 vt = btf__type_by_id(btf, v->type);
395 printf(" (%s '%s')",
396 btf_kind_str[btf_kind_safe(btf_kind(vt))],
397 btf_str(btf, vt->name_off));
398 }
399 }
400 }
401 if (json_output)
402 jsonw_end_array(w);
403 break;
404 }
405 case BTF_KIND_FLOAT: {
406 if (json_output)
407 jsonw_uint_field(w, "size", t->size);
408 else
409 printf(" size=%u", t->size);
410 break;
411 }
412 case BTF_KIND_DECL_TAG: {
413 const struct btf_decl_tag *tag = (const void *)(t + 1);
414
415 if (json_output) {
416 jsonw_uint_field(w, "type_id", t->type);
417 jsonw_int_field(w, "component_idx", tag->component_idx);
418 } else {
419 printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
420 }
421 break;
422 }
423 default:
424 break;
425 }
426
427 if (json_output)
428 jsonw_end_object(json_wtr);
429 else
430 printf("\n");
431
432 return 0;
433 }
434
dump_btf_raw(const struct btf * btf,__u32 * root_type_ids,int root_type_cnt)435 static int dump_btf_raw(const struct btf *btf,
436 __u32 *root_type_ids, int root_type_cnt)
437 {
438 const struct btf_type *t;
439 int i;
440
441 if (json_output) {
442 jsonw_start_object(json_wtr);
443 jsonw_name(json_wtr, "types");
444 jsonw_start_array(json_wtr);
445 }
446
447 if (root_type_cnt) {
448 for (i = 0; i < root_type_cnt; i++) {
449 t = btf__type_by_id(btf, root_type_ids[i]);
450 dump_btf_type(btf, root_type_ids[i], t);
451 }
452 } else {
453 const struct btf *base;
454 int cnt = btf__type_cnt(btf);
455 int start_id = 1;
456
457 base = btf__base_btf(btf);
458 if (base)
459 start_id = btf__type_cnt(base);
460
461 for (i = start_id; i < cnt; i++) {
462 t = btf__type_by_id(btf, i);
463 dump_btf_type(btf, i, t);
464 }
465 }
466
467 if (json_output) {
468 jsonw_end_array(json_wtr);
469 jsonw_end_object(json_wtr);
470 }
471 return 0;
472 }
473
474 struct ptr_array {
475 __u32 cnt;
476 __u32 cap;
477 const void **elems;
478 };
479
ptr_array_push(const void * ptr,struct ptr_array * arr)480 static int ptr_array_push(const void *ptr, struct ptr_array *arr)
481 {
482 __u32 new_cap;
483 void *tmp;
484
485 if (arr->cnt == arr->cap) {
486 new_cap = (arr->cap ?: 16) * 2;
487 tmp = realloc(arr->elems, sizeof(*arr->elems) * new_cap);
488 if (!tmp)
489 return -ENOMEM;
490 arr->elems = tmp;
491 arr->cap = new_cap;
492 }
493 arr->elems[arr->cnt++] = ptr;
494 return 0;
495 }
496
ptr_array_free(struct ptr_array * arr)497 static void ptr_array_free(struct ptr_array *arr)
498 {
499 free(arr->elems);
500 }
501
cmp_kfuncs(const void * pa,const void * pb,void * ctx)502 static int cmp_kfuncs(const void *pa, const void *pb, void *ctx)
503 {
504 struct btf *btf = ctx;
505 const struct btf_type *a = *(void **)pa;
506 const struct btf_type *b = *(void **)pb;
507
508 return strcmp(btf__str_by_offset(btf, a->name_off),
509 btf__str_by_offset(btf, b->name_off));
510 }
511
dump_btf_kfuncs(struct btf_dump * d,const struct btf * btf)512 static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf)
513 {
514 LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts);
515 __u32 cnt = btf__type_cnt(btf), i, j;
516 struct ptr_array fastcalls = {};
517 struct ptr_array kfuncs = {};
518 int err = 0;
519
520 printf("\n/* BPF kfuncs */\n");
521 printf("#ifndef BPF_NO_KFUNC_PROTOTYPES\n");
522
523 for (i = 1; i < cnt; i++) {
524 const struct btf_type *t = btf__type_by_id(btf, i);
525 const struct btf_type *ft;
526 const char *name;
527
528 if (!btf_is_decl_tag(t))
529 continue;
530
531 if (btf_decl_tag(t)->component_idx != -1)
532 continue;
533
534 ft = btf__type_by_id(btf, t->type);
535 if (!btf_is_func(ft))
536 continue;
537
538 name = btf__name_by_offset(btf, t->name_off);
539 if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG)) == 0) {
540 err = ptr_array_push(ft, &kfuncs);
541 if (err)
542 goto out;
543 }
544
545 if (strncmp(name, FASTCALL_DECL_TAG, sizeof(FASTCALL_DECL_TAG)) == 0) {
546 err = ptr_array_push(ft, &fastcalls);
547 if (err)
548 goto out;
549 }
550 }
551
552 /* Sort kfuncs by name for improved vmlinux.h stability */
553 qsort_r(kfuncs.elems, kfuncs.cnt, sizeof(*kfuncs.elems), cmp_kfuncs, (void *)btf);
554 for (i = 0; i < kfuncs.cnt; i++) {
555 const struct btf_type *t = kfuncs.elems[i];
556
557 printf("extern ");
558
559 /* Assume small amount of fastcall kfuncs */
560 for (j = 0; j < fastcalls.cnt; j++) {
561 if (fastcalls.elems[j] == t) {
562 printf("__bpf_fastcall ");
563 break;
564 }
565 }
566
567 opts.field_name = btf__name_by_offset(btf, t->name_off);
568 err = btf_dump__emit_type_decl(d, t->type, &opts);
569 if (err)
570 goto out;
571
572 printf(" __weak __ksym;\n");
573 }
574
575 printf("#endif\n\n");
576
577 out:
578 ptr_array_free(&fastcalls);
579 ptr_array_free(&kfuncs);
580 return err;
581 }
582
btf_dump_printf(void * ctx,const char * fmt,va_list args)583 static void __printf(2, 0) btf_dump_printf(void *ctx,
584 const char *fmt, va_list args)
585 {
586 vfprintf(stdout, fmt, args);
587 }
588
btf_type_rank(const struct btf * btf,__u32 index,bool has_name)589 static int btf_type_rank(const struct btf *btf, __u32 index, bool has_name)
590 {
591 const struct btf_type *t = btf__type_by_id(btf, index);
592 const int kind = btf_kind(t);
593 const int max_rank = 10;
594
595 if (t->name_off)
596 has_name = true;
597
598 switch (kind) {
599 case BTF_KIND_ENUM:
600 case BTF_KIND_ENUM64:
601 return has_name ? 1 : 0;
602 case BTF_KIND_INT:
603 case BTF_KIND_FLOAT:
604 return 2;
605 case BTF_KIND_STRUCT:
606 case BTF_KIND_UNION:
607 return has_name ? 3 : max_rank;
608 case BTF_KIND_FUNC_PROTO:
609 return has_name ? 4 : max_rank;
610 case BTF_KIND_ARRAY:
611 if (has_name)
612 return btf_type_rank(btf, btf_array(t)->type, has_name);
613 return max_rank;
614 case BTF_KIND_TYPE_TAG:
615 case BTF_KIND_CONST:
616 case BTF_KIND_PTR:
617 case BTF_KIND_VOLATILE:
618 case BTF_KIND_RESTRICT:
619 case BTF_KIND_TYPEDEF:
620 case BTF_KIND_DECL_TAG:
621 if (has_name)
622 return btf_type_rank(btf, t->type, has_name);
623 return max_rank;
624 default:
625 return max_rank;
626 }
627 }
628
btf_type_sort_name(const struct btf * btf,__u32 index,bool from_ref)629 static const char *btf_type_sort_name(const struct btf *btf, __u32 index, bool from_ref)
630 {
631 const struct btf_type *t = btf__type_by_id(btf, index);
632
633 switch (btf_kind(t)) {
634 case BTF_KIND_ENUM:
635 case BTF_KIND_ENUM64: {
636 int name_off = t->name_off;
637
638 if (!from_ref && !name_off && btf_vlen(t))
639 name_off = btf_kind(t) == BTF_KIND_ENUM64 ?
640 btf_enum64(t)->name_off :
641 btf_enum(t)->name_off;
642
643 return btf__name_by_offset(btf, name_off);
644 }
645 case BTF_KIND_ARRAY:
646 return btf_type_sort_name(btf, btf_array(t)->type, true);
647 case BTF_KIND_TYPE_TAG:
648 case BTF_KIND_CONST:
649 case BTF_KIND_PTR:
650 case BTF_KIND_VOLATILE:
651 case BTF_KIND_RESTRICT:
652 case BTF_KIND_TYPEDEF:
653 case BTF_KIND_DECL_TAG:
654 return btf_type_sort_name(btf, t->type, true);
655 default:
656 return btf__name_by_offset(btf, t->name_off);
657 }
658 return NULL;
659 }
660
hasher(__u64 hash,__u64 val)661 static __u64 hasher(__u64 hash, __u64 val)
662 {
663 return hash * 31 + val;
664 }
665
btf_name_hasher(__u64 hash,const struct btf * btf,__u32 name_off)666 static __u64 btf_name_hasher(__u64 hash, const struct btf *btf, __u32 name_off)
667 {
668 if (!name_off)
669 return hash;
670
671 return hasher(hash, str_hash(btf__name_by_offset(btf, name_off)));
672 }
673
btf_type_disambig_hash(const struct btf * btf,__u32 id,bool include_members)674 static __u64 btf_type_disambig_hash(const struct btf *btf, __u32 id, bool include_members)
675 {
676 const struct btf_type *t = btf__type_by_id(btf, id);
677 int i;
678 size_t hash = 0;
679
680 hash = btf_name_hasher(hash, btf, t->name_off);
681
682 switch (btf_kind(t)) {
683 case BTF_KIND_ENUM:
684 case BTF_KIND_ENUM64:
685 for (i = 0; i < btf_vlen(t); i++) {
686 __u32 name_off = btf_is_enum(t) ?
687 btf_enum(t)[i].name_off :
688 btf_enum64(t)[i].name_off;
689
690 hash = btf_name_hasher(hash, btf, name_off);
691 }
692 break;
693 case BTF_KIND_STRUCT:
694 case BTF_KIND_UNION:
695 if (!include_members)
696 break;
697 for (i = 0; i < btf_vlen(t); i++) {
698 const struct btf_member *m = btf_members(t) + i;
699
700 hash = btf_name_hasher(hash, btf, m->name_off);
701 /* resolve field type's name and hash it as well */
702 hash = hasher(hash, btf_type_disambig_hash(btf, m->type, false));
703 }
704 break;
705 case BTF_KIND_TYPE_TAG:
706 case BTF_KIND_CONST:
707 case BTF_KIND_PTR:
708 case BTF_KIND_VOLATILE:
709 case BTF_KIND_RESTRICT:
710 case BTF_KIND_TYPEDEF:
711 case BTF_KIND_DECL_TAG:
712 hash = hasher(hash, btf_type_disambig_hash(btf, t->type, include_members));
713 break;
714 case BTF_KIND_ARRAY: {
715 struct btf_array *arr = btf_array(t);
716
717 hash = hasher(hash, arr->nelems);
718 hash = hasher(hash, btf_type_disambig_hash(btf, arr->type, include_members));
719 break;
720 }
721 default:
722 break;
723 }
724 return hash;
725 }
726
btf_type_compare(const void * left,const void * right)727 static int btf_type_compare(const void *left, const void *right)
728 {
729 const struct sort_datum *d1 = (const struct sort_datum *)left;
730 const struct sort_datum *d2 = (const struct sort_datum *)right;
731 int r;
732
733 r = d1->type_rank - d2->type_rank;
734 r = r ?: strcmp(d1->sort_name, d2->sort_name);
735 r = r ?: strcmp(d1->own_name, d2->own_name);
736 if (r)
737 return r;
738
739 if (d1->disambig_hash != d2->disambig_hash)
740 return d1->disambig_hash < d2->disambig_hash ? -1 : 1;
741
742 return d1->index - d2->index;
743 }
744
sort_btf_c(const struct btf * btf)745 static struct sort_datum *sort_btf_c(const struct btf *btf)
746 {
747 struct sort_datum *datums;
748 int n;
749
750 n = btf__type_cnt(btf);
751 datums = malloc(sizeof(struct sort_datum) * n);
752 if (!datums)
753 return NULL;
754
755 for (int i = 0; i < n; ++i) {
756 struct sort_datum *d = datums + i;
757 const struct btf_type *t = btf__type_by_id(btf, i);
758
759 d->index = i;
760 d->type_rank = btf_type_rank(btf, i, false);
761 d->sort_name = btf_type_sort_name(btf, i, false);
762 d->own_name = btf__name_by_offset(btf, t->name_off);
763 d->disambig_hash = btf_type_disambig_hash(btf, i, true);
764 }
765
766 qsort(datums, n, sizeof(struct sort_datum), btf_type_compare);
767
768 return datums;
769 }
770
dump_btf_c(const struct btf * btf,__u32 * root_type_ids,int root_type_cnt,bool sort_dump)771 static int dump_btf_c(const struct btf *btf,
772 __u32 *root_type_ids, int root_type_cnt, bool sort_dump)
773 {
774 struct sort_datum *datums = NULL;
775 struct btf_dump *d;
776 int err = 0, i;
777
778 d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
779 if (!d)
780 return -errno;
781
782 printf("#ifndef __VMLINUX_H__\n");
783 printf("#define __VMLINUX_H__\n");
784 printf("\n");
785 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
786 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
787 printf("#endif\n\n");
788 printf("#ifndef __ksym\n");
789 printf("#define __ksym __attribute__((section(\".ksyms\")))\n");
790 printf("#endif\n\n");
791 printf("#ifndef __weak\n");
792 printf("#define __weak __attribute__((weak))\n");
793 printf("#endif\n\n");
794 printf("#ifndef __bpf_fastcall\n");
795 printf("#if __has_attribute(bpf_fastcall)\n");
796 printf("#define __bpf_fastcall __attribute__((bpf_fastcall))\n");
797 printf("#else\n");
798 printf("#define __bpf_fastcall\n");
799 printf("#endif\n");
800 printf("#endif\n\n");
801
802 if (root_type_cnt) {
803 for (i = 0; i < root_type_cnt; i++) {
804 err = btf_dump__dump_type(d, root_type_ids[i]);
805 if (err)
806 goto done;
807 }
808 } else {
809 int cnt = btf__type_cnt(btf);
810
811 if (sort_dump)
812 datums = sort_btf_c(btf);
813 for (i = 1; i < cnt; i++) {
814 int idx = datums ? datums[i].index : i;
815
816 err = btf_dump__dump_type(d, idx);
817 if (err)
818 goto done;
819 }
820
821 err = dump_btf_kfuncs(d, btf);
822 if (err)
823 goto done;
824 }
825
826 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
827 printf("#pragma clang attribute pop\n");
828 printf("#endif\n");
829 printf("\n");
830 printf("#endif /* __VMLINUX_H__ */\n");
831
832 done:
833 free(datums);
834 btf_dump__free(d);
835 return err;
836 }
837
838 static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
839
get_vmlinux_btf_from_sysfs(void)840 static struct btf *get_vmlinux_btf_from_sysfs(void)
841 {
842 struct btf *base;
843
844 base = btf__parse(sysfs_vmlinux, NULL);
845 if (!base)
846 p_err("failed to parse vmlinux BTF at '%s': %d\n",
847 sysfs_vmlinux, -errno);
848
849 return base;
850 }
851
852 #define BTF_NAME_BUFF_LEN 64
853
btf_is_kernel_module(__u32 btf_id)854 static bool btf_is_kernel_module(__u32 btf_id)
855 {
856 struct bpf_btf_info btf_info = {};
857 char btf_name[BTF_NAME_BUFF_LEN];
858 int btf_fd;
859 __u32 len;
860 int err;
861
862 btf_fd = bpf_btf_get_fd_by_id(btf_id);
863 if (btf_fd < 0) {
864 p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
865 return false;
866 }
867
868 len = sizeof(btf_info);
869 btf_info.name = ptr_to_u64(btf_name);
870 btf_info.name_len = sizeof(btf_name);
871 err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
872 close(btf_fd);
873 if (err) {
874 p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
875 return false;
876 }
877
878 return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
879 }
880
do_dump(int argc,char ** argv)881 static int do_dump(int argc, char **argv)
882 {
883 bool dump_c = false, sort_dump_c = true;
884 struct btf *btf = NULL, *base = NULL;
885 __u32 root_type_ids[MAX_ROOT_IDS];
886 bool have_id_filtering;
887 int root_type_cnt = 0;
888 __u32 btf_id = -1;
889 const char *src;
890 int fd = -1;
891 int err = 0;
892 int i;
893
894 if (!REQ_ARGS(2)) {
895 usage();
896 return -1;
897 }
898 src = GET_ARG();
899 if (is_prefix(src, "map")) {
900 struct bpf_map_info info = {};
901 __u32 len = sizeof(info);
902
903 if (!REQ_ARGS(2)) {
904 usage();
905 return -1;
906 }
907
908 fd = map_parse_fd_and_info(&argc, &argv, &info, &len);
909 if (fd < 0)
910 return -1;
911
912 btf_id = info.btf_id;
913 if (argc && is_prefix(*argv, "key")) {
914 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
915 NEXT_ARG();
916 } else if (argc && is_prefix(*argv, "value")) {
917 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
918 NEXT_ARG();
919 } else if (argc && is_prefix(*argv, "all")) {
920 NEXT_ARG();
921 } else if (argc && is_prefix(*argv, "kv")) {
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 NEXT_ARG();
925 } else {
926 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
927 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
928 }
929 } else if (is_prefix(src, "prog")) {
930 struct bpf_prog_info info = {};
931 __u32 len = sizeof(info);
932
933 if (!REQ_ARGS(2)) {
934 usage();
935 return -1;
936 }
937
938 fd = prog_parse_fd(&argc, &argv);
939 if (fd < 0)
940 return -1;
941
942 err = bpf_prog_get_info_by_fd(fd, &info, &len);
943 if (err) {
944 p_err("can't get prog info: %s", strerror(errno));
945 goto done;
946 }
947
948 btf_id = info.btf_id;
949 } else if (is_prefix(src, "id")) {
950 char *endptr;
951
952 btf_id = strtoul(*argv, &endptr, 0);
953 if (*endptr) {
954 p_err("can't parse %s as ID", *argv);
955 return -1;
956 }
957 NEXT_ARG();
958 } else if (is_prefix(src, "file")) {
959 const char sysfs_prefix[] = "/sys/kernel/btf/";
960
961 if (!base_btf &&
962 strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
963 strcmp(*argv, sysfs_vmlinux) != 0)
964 base = get_vmlinux_btf_from_sysfs();
965
966 btf = btf__parse_split(*argv, base ?: base_btf);
967 if (!btf) {
968 err = -errno;
969 p_err("failed to load BTF from %s: %s",
970 *argv, strerror(errno));
971 goto done;
972 }
973 NEXT_ARG();
974 } else {
975 err = -1;
976 p_err("unrecognized BTF source specifier: '%s'", src);
977 goto done;
978 }
979
980 have_id_filtering = !!root_type_cnt;
981
982 while (argc) {
983 if (is_prefix(*argv, "format")) {
984 NEXT_ARG();
985 if (argc < 1) {
986 p_err("expecting value for 'format' option\n");
987 err = -EINVAL;
988 goto done;
989 }
990 if (strcmp(*argv, "c") == 0) {
991 dump_c = true;
992 } else if (strcmp(*argv, "raw") == 0) {
993 dump_c = false;
994 } else {
995 p_err("unrecognized format specifier: '%s', possible values: raw, c",
996 *argv);
997 err = -EINVAL;
998 goto done;
999 }
1000 NEXT_ARG();
1001 } else if (is_prefix(*argv, "root_id")) {
1002 __u32 root_id;
1003 char *end;
1004
1005 if (have_id_filtering) {
1006 p_err("cannot use root_id with other type filtering");
1007 err = -EINVAL;
1008 goto done;
1009 } else if (root_type_cnt == MAX_ROOT_IDS) {
1010 p_err("only %d root_id are supported", MAX_ROOT_IDS);
1011 err = -E2BIG;
1012 goto done;
1013 }
1014
1015 NEXT_ARG();
1016 root_id = strtoul(*argv, &end, 0);
1017 if (*end) {
1018 err = -1;
1019 p_err("can't parse %s as root ID", *argv);
1020 goto done;
1021 }
1022 for (i = 0; i < root_type_cnt; i++) {
1023 if (root_type_ids[i] == root_id) {
1024 err = -EINVAL;
1025 p_err("duplicate root_id %d supplied", root_id);
1026 goto done;
1027 }
1028 }
1029 root_type_ids[root_type_cnt++] = root_id;
1030 NEXT_ARG();
1031 } else if (is_prefix(*argv, "unsorted")) {
1032 sort_dump_c = false;
1033 NEXT_ARG();
1034 } else {
1035 p_err("unrecognized option: '%s'", *argv);
1036 err = -EINVAL;
1037 goto done;
1038 }
1039 }
1040
1041 if (!btf) {
1042 if (!base_btf && btf_is_kernel_module(btf_id)) {
1043 p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
1044 sysfs_vmlinux);
1045 base_btf = get_vmlinux_btf_from_sysfs();
1046 }
1047
1048 btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
1049 if (!btf) {
1050 err = -errno;
1051 p_err("get btf by id (%u): %s", btf_id, strerror(errno));
1052 goto done;
1053 }
1054 }
1055
1056 /* Invalid root IDs causes half emitted boilerplate and then unclean
1057 * exit. It's an ugly user experience, so handle common error here.
1058 */
1059 for (i = 0; i < root_type_cnt; i++) {
1060 if (root_type_ids[i] >= btf__type_cnt(btf)) {
1061 err = -EINVAL;
1062 p_err("invalid root ID: %u", root_type_ids[i]);
1063 goto done;
1064 }
1065 }
1066
1067 if (dump_c) {
1068 if (json_output) {
1069 p_err("JSON output for C-syntax dump is not supported");
1070 err = -ENOTSUP;
1071 goto done;
1072 }
1073 err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c);
1074 } else {
1075 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
1076 }
1077
1078 done:
1079 close(fd);
1080 btf__free(btf);
1081 btf__free(base);
1082 return err;
1083 }
1084
btf_parse_fd(int * argc,char *** argv)1085 static int btf_parse_fd(int *argc, char ***argv)
1086 {
1087 unsigned int id;
1088 char *endptr;
1089 int fd;
1090
1091 if (!is_prefix(*argv[0], "id")) {
1092 p_err("expected 'id', got: '%s'?", **argv);
1093 return -1;
1094 }
1095 NEXT_ARGP();
1096
1097 id = strtoul(**argv, &endptr, 0);
1098 if (*endptr) {
1099 p_err("can't parse %s as ID", **argv);
1100 return -1;
1101 }
1102 NEXT_ARGP();
1103
1104 fd = bpf_btf_get_fd_by_id(id);
1105 if (fd < 0)
1106 p_err("can't get BTF object by id (%u): %s",
1107 id, strerror(errno));
1108
1109 return fd;
1110 }
1111
1112 static int
build_btf_type_table(struct hashmap * tab,enum bpf_obj_type type,void * info,__u32 * len)1113 build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
1114 void *info, __u32 *len)
1115 {
1116 static const char * const names[] = {
1117 [BPF_OBJ_UNKNOWN] = "unknown",
1118 [BPF_OBJ_PROG] = "prog",
1119 [BPF_OBJ_MAP] = "map",
1120 };
1121 __u32 btf_id, id = 0;
1122 int err;
1123 int fd;
1124
1125 while (true) {
1126 switch (type) {
1127 case BPF_OBJ_PROG:
1128 err = bpf_prog_get_next_id(id, &id);
1129 break;
1130 case BPF_OBJ_MAP:
1131 err = bpf_map_get_next_id(id, &id);
1132 break;
1133 default:
1134 err = -1;
1135 p_err("unexpected object type: %d", type);
1136 goto err_free;
1137 }
1138 if (err) {
1139 if (errno == ENOENT) {
1140 err = 0;
1141 break;
1142 }
1143 p_err("can't get next %s: %s%s", names[type],
1144 strerror(errno),
1145 errno == EINVAL ? " -- kernel too old?" : "");
1146 goto err_free;
1147 }
1148
1149 switch (type) {
1150 case BPF_OBJ_PROG:
1151 fd = bpf_prog_get_fd_by_id(id);
1152 break;
1153 case BPF_OBJ_MAP:
1154 fd = bpf_map_get_fd_by_id(id);
1155 break;
1156 default:
1157 err = -1;
1158 p_err("unexpected object type: %d", type);
1159 goto err_free;
1160 }
1161 if (fd < 0) {
1162 if (errno == ENOENT)
1163 continue;
1164 p_err("can't get %s by id (%u): %s", names[type], id,
1165 strerror(errno));
1166 err = -1;
1167 goto err_free;
1168 }
1169
1170 memset(info, 0, *len);
1171 if (type == BPF_OBJ_PROG)
1172 err = bpf_prog_get_info_by_fd(fd, info, len);
1173 else
1174 err = bpf_map_get_info_by_fd(fd, info, len);
1175 close(fd);
1176 if (err) {
1177 p_err("can't get %s info: %s", names[type],
1178 strerror(errno));
1179 goto err_free;
1180 }
1181
1182 switch (type) {
1183 case BPF_OBJ_PROG:
1184 btf_id = ((struct bpf_prog_info *)info)->btf_id;
1185 break;
1186 case BPF_OBJ_MAP:
1187 btf_id = ((struct bpf_map_info *)info)->btf_id;
1188 break;
1189 default:
1190 err = -1;
1191 p_err("unexpected object type: %d", type);
1192 goto err_free;
1193 }
1194 if (!btf_id)
1195 continue;
1196
1197 err = hashmap__append(tab, btf_id, id);
1198 if (err) {
1199 p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
1200 btf_id, id, strerror(-err));
1201 goto err_free;
1202 }
1203 }
1204
1205 return 0;
1206
1207 err_free:
1208 hashmap__free(tab);
1209 return err;
1210 }
1211
1212 static int
build_btf_tables(struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1213 build_btf_tables(struct hashmap *btf_prog_table,
1214 struct hashmap *btf_map_table)
1215 {
1216 struct bpf_prog_info prog_info;
1217 __u32 prog_len = sizeof(prog_info);
1218 struct bpf_map_info map_info;
1219 __u32 map_len = sizeof(map_info);
1220 int err = 0;
1221
1222 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
1223 &prog_len);
1224 if (err)
1225 return err;
1226
1227 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
1228 &map_len);
1229 if (err) {
1230 hashmap__free(btf_prog_table);
1231 return err;
1232 }
1233
1234 return 0;
1235 }
1236
1237 static void
show_btf_plain(struct bpf_btf_info * info,int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1238 show_btf_plain(struct bpf_btf_info *info, int fd,
1239 struct hashmap *btf_prog_table,
1240 struct hashmap *btf_map_table)
1241 {
1242 struct hashmap_entry *entry;
1243 const char *name = u64_to_ptr(info->name);
1244 int n;
1245
1246 printf("%u: ", info->id);
1247 if (info->kernel_btf)
1248 printf("name [%s] ", name);
1249 else if (name && name[0])
1250 printf("name %s ", name);
1251 else
1252 printf("name <anon> ");
1253 printf("size %uB", info->btf_size);
1254
1255 n = 0;
1256 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1257 printf("%s%lu", n++ == 0 ? " prog_ids " : ",", entry->value);
1258 }
1259
1260 n = 0;
1261 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1262 printf("%s%lu", n++ == 0 ? " map_ids " : ",", entry->value);
1263 }
1264
1265 emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
1266
1267 printf("\n");
1268 }
1269
1270 static void
show_btf_json(struct bpf_btf_info * info,int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1271 show_btf_json(struct bpf_btf_info *info, int fd,
1272 struct hashmap *btf_prog_table,
1273 struct hashmap *btf_map_table)
1274 {
1275 struct hashmap_entry *entry;
1276 const char *name = u64_to_ptr(info->name);
1277
1278 jsonw_start_object(json_wtr); /* btf object */
1279 jsonw_uint_field(json_wtr, "id", info->id);
1280 jsonw_uint_field(json_wtr, "size", info->btf_size);
1281
1282 jsonw_name(json_wtr, "prog_ids");
1283 jsonw_start_array(json_wtr); /* prog_ids */
1284 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1285 jsonw_uint(json_wtr, entry->value);
1286 }
1287 jsonw_end_array(json_wtr); /* prog_ids */
1288
1289 jsonw_name(json_wtr, "map_ids");
1290 jsonw_start_array(json_wtr); /* map_ids */
1291 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1292 jsonw_uint(json_wtr, entry->value);
1293 }
1294 jsonw_end_array(json_wtr); /* map_ids */
1295
1296 emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */
1297
1298 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
1299
1300 if (name && name[0])
1301 jsonw_string_field(json_wtr, "name", name);
1302
1303 jsonw_end_object(json_wtr); /* btf object */
1304 }
1305
1306 static int
show_btf(int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1307 show_btf(int fd, struct hashmap *btf_prog_table,
1308 struct hashmap *btf_map_table)
1309 {
1310 struct bpf_btf_info info;
1311 __u32 len = sizeof(info);
1312 char name[64];
1313 int err;
1314
1315 memset(&info, 0, sizeof(info));
1316 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1317 if (err) {
1318 p_err("can't get BTF object info: %s", strerror(errno));
1319 return -1;
1320 }
1321 /* if kernel support emitting BTF object name, pass name pointer */
1322 if (info.name_len) {
1323 memset(&info, 0, sizeof(info));
1324 info.name_len = sizeof(name);
1325 info.name = ptr_to_u64(name);
1326 len = sizeof(info);
1327
1328 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1329 if (err) {
1330 p_err("can't get BTF object info: %s", strerror(errno));
1331 return -1;
1332 }
1333 }
1334
1335 if (json_output)
1336 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
1337 else
1338 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
1339
1340 return 0;
1341 }
1342
do_show(int argc,char ** argv)1343 static int do_show(int argc, char **argv)
1344 {
1345 struct hashmap *btf_prog_table;
1346 struct hashmap *btf_map_table;
1347 int err, fd = -1;
1348 __u32 id = 0;
1349
1350 if (argc == 2) {
1351 fd = btf_parse_fd(&argc, &argv);
1352 if (fd < 0)
1353 return -1;
1354 }
1355
1356 if (argc) {
1357 if (fd >= 0)
1358 close(fd);
1359 return BAD_ARG();
1360 }
1361
1362 btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
1363 equal_fn_for_key_as_id, NULL);
1364 btf_map_table = hashmap__new(hash_fn_for_key_as_id,
1365 equal_fn_for_key_as_id, NULL);
1366 if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
1367 hashmap__free(btf_prog_table);
1368 hashmap__free(btf_map_table);
1369 if (fd >= 0)
1370 close(fd);
1371 p_err("failed to create hashmap for object references");
1372 return -1;
1373 }
1374 err = build_btf_tables(btf_prog_table, btf_map_table);
1375 if (err) {
1376 if (fd >= 0)
1377 close(fd);
1378 return err;
1379 }
1380 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
1381
1382 if (fd >= 0) {
1383 err = show_btf(fd, btf_prog_table, btf_map_table);
1384 close(fd);
1385 goto exit_free;
1386 }
1387
1388 if (json_output)
1389 jsonw_start_array(json_wtr); /* root array */
1390
1391 while (true) {
1392 err = bpf_btf_get_next_id(id, &id);
1393 if (err) {
1394 if (errno == ENOENT) {
1395 err = 0;
1396 break;
1397 }
1398 p_err("can't get next BTF object: %s%s",
1399 strerror(errno),
1400 errno == EINVAL ? " -- kernel too old?" : "");
1401 err = -1;
1402 break;
1403 }
1404
1405 fd = bpf_btf_get_fd_by_id(id);
1406 if (fd < 0) {
1407 if (errno == ENOENT)
1408 continue;
1409 p_err("can't get BTF object by id (%u): %s",
1410 id, strerror(errno));
1411 err = -1;
1412 break;
1413 }
1414
1415 err = show_btf(fd, btf_prog_table, btf_map_table);
1416 close(fd);
1417 if (err)
1418 break;
1419 }
1420
1421 if (json_output)
1422 jsonw_end_array(json_wtr); /* root array */
1423
1424 exit_free:
1425 hashmap__free(btf_prog_table);
1426 hashmap__free(btf_map_table);
1427 delete_obj_refs_table(refs_table);
1428
1429 return err;
1430 }
1431
do_help(int argc,char ** argv)1432 static int do_help(int argc, char **argv)
1433 {
1434 if (json_output) {
1435 jsonw_null(json_wtr);
1436 return 0;
1437 }
1438
1439 fprintf(stderr,
1440 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
1441 " %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n"
1442 " %1$s %2$s help\n"
1443 "\n"
1444 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
1445 " FORMAT := { raw | c [unsorted] }\n"
1446 " " HELP_SPEC_MAP "\n"
1447 " " HELP_SPEC_PROGRAM "\n"
1448 " " HELP_SPEC_OPTIONS " |\n"
1449 " {-B|--base-btf} }\n"
1450 "",
1451 bin_name, "btf");
1452
1453 return 0;
1454 }
1455
1456 static const struct cmd cmds[] = {
1457 { "show", do_show },
1458 { "list", do_show },
1459 { "help", do_help },
1460 { "dump", do_dump },
1461 { 0 }
1462 };
1463
do_btf(int argc,char ** argv)1464 int do_btf(int argc, char **argv)
1465 {
1466 return cmd_select(cmds, argc, argv, do_help);
1467 }
1468