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 #define MAX_BTF_FILES 64
32
33 static const char * const btf_kind_str[NR_BTF_KINDS] = {
34 [BTF_KIND_UNKN] = "UNKNOWN",
35 [BTF_KIND_INT] = "INT",
36 [BTF_KIND_PTR] = "PTR",
37 [BTF_KIND_ARRAY] = "ARRAY",
38 [BTF_KIND_STRUCT] = "STRUCT",
39 [BTF_KIND_UNION] = "UNION",
40 [BTF_KIND_ENUM] = "ENUM",
41 [BTF_KIND_FWD] = "FWD",
42 [BTF_KIND_TYPEDEF] = "TYPEDEF",
43 [BTF_KIND_VOLATILE] = "VOLATILE",
44 [BTF_KIND_CONST] = "CONST",
45 [BTF_KIND_RESTRICT] = "RESTRICT",
46 [BTF_KIND_FUNC] = "FUNC",
47 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
48 [BTF_KIND_VAR] = "VAR",
49 [BTF_KIND_DATASEC] = "DATASEC",
50 [BTF_KIND_FLOAT] = "FLOAT",
51 [BTF_KIND_DECL_TAG] = "DECL_TAG",
52 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
53 [BTF_KIND_ENUM64] = "ENUM64",
54 };
55
56 struct sort_datum {
57 int index;
58 int type_rank;
59 const char *sort_name;
60 const char *own_name;
61 __u64 disambig_hash;
62 };
63
btf_int_enc_str(__u8 encoding)64 static const char *btf_int_enc_str(__u8 encoding)
65 {
66 switch (encoding) {
67 case 0:
68 return "(none)";
69 case BTF_INT_SIGNED:
70 return "SIGNED";
71 case BTF_INT_CHAR:
72 return "CHAR";
73 case BTF_INT_BOOL:
74 return "BOOL";
75 default:
76 return "UNKN";
77 }
78 }
79
btf_var_linkage_str(__u32 linkage)80 static const char *btf_var_linkage_str(__u32 linkage)
81 {
82 switch (linkage) {
83 case BTF_VAR_STATIC:
84 return "static";
85 case BTF_VAR_GLOBAL_ALLOCATED:
86 return "global";
87 case BTF_VAR_GLOBAL_EXTERN:
88 return "extern";
89 default:
90 return "(unknown)";
91 }
92 }
93
btf_func_linkage_str(const struct btf_type * t)94 static const char *btf_func_linkage_str(const struct btf_type *t)
95 {
96 switch (btf_vlen(t)) {
97 case BTF_FUNC_STATIC:
98 return "static";
99 case BTF_FUNC_GLOBAL:
100 return "global";
101 case BTF_FUNC_EXTERN:
102 return "extern";
103 default:
104 return "(unknown)";
105 }
106 }
107
btf_str(const struct btf * btf,__u32 off)108 static const char *btf_str(const struct btf *btf, __u32 off)
109 {
110 if (!off)
111 return "(anon)";
112 return btf__name_by_offset(btf, off) ? : "(invalid)";
113 }
114
btf_kind_safe(int kind)115 static int btf_kind_safe(int kind)
116 {
117 return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN;
118 }
119
dump_btf_type(const struct btf * btf,__u32 id,const struct btf_type * t)120 static int dump_btf_type(const struct btf *btf, __u32 id,
121 const struct btf_type *t)
122 {
123 json_writer_t *w = json_wtr;
124 int kind = btf_kind(t);
125
126 if (json_output) {
127 jsonw_start_object(w);
128 jsonw_uint_field(w, "id", id);
129 jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]);
130 jsonw_string_field(w, "name", btf_str(btf, t->name_off));
131 } else {
132 printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)],
133 btf_str(btf, t->name_off));
134 }
135
136 switch (kind) {
137 case BTF_KIND_INT: {
138 __u32 v = *(__u32 *)(t + 1);
139 const char *enc;
140
141 enc = btf_int_enc_str(BTF_INT_ENCODING(v));
142
143 if (json_output) {
144 jsonw_uint_field(w, "size", t->size);
145 jsonw_uint_field(w, "bits_offset", BTF_INT_OFFSET(v));
146 jsonw_uint_field(w, "nr_bits", BTF_INT_BITS(v));
147 jsonw_string_field(w, "encoding", enc);
148 } else {
149 printf(" size=%u bits_offset=%u nr_bits=%u encoding=%s",
150 t->size, BTF_INT_OFFSET(v), BTF_INT_BITS(v),
151 enc);
152 }
153 break;
154 }
155 case BTF_KIND_PTR:
156 case BTF_KIND_CONST:
157 case BTF_KIND_VOLATILE:
158 case BTF_KIND_RESTRICT:
159 case BTF_KIND_TYPEDEF:
160 case BTF_KIND_TYPE_TAG:
161 if (json_output)
162 jsonw_uint_field(w, "type_id", t->type);
163 else
164 printf(" type_id=%u", t->type);
165 break;
166 case BTF_KIND_ARRAY: {
167 const struct btf_array *arr = (const void *)(t + 1);
168
169 if (json_output) {
170 jsonw_uint_field(w, "type_id", arr->type);
171 jsonw_uint_field(w, "index_type_id", arr->index_type);
172 jsonw_uint_field(w, "nr_elems", arr->nelems);
173 } else {
174 printf(" type_id=%u index_type_id=%u nr_elems=%u",
175 arr->type, arr->index_type, arr->nelems);
176 }
177 break;
178 }
179 case BTF_KIND_STRUCT:
180 case BTF_KIND_UNION: {
181 const struct btf_member *m = (const void *)(t + 1);
182 __u32 i, vlen = btf_vlen(t);
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_kflag(t)) {
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 __u32 i, vlen = btf_vlen(t);
228 const char *encoding;
229
230 encoding = btf_kflag(t) ? "SIGNED" : "UNSIGNED";
231 if (json_output) {
232 jsonw_string_field(w, "encoding", encoding);
233 jsonw_uint_field(w, "size", t->size);
234 jsonw_uint_field(w, "vlen", vlen);
235 jsonw_name(w, "values");
236 jsonw_start_array(w);
237 } else {
238 printf(" encoding=%s size=%u vlen=%u", encoding, t->size, vlen);
239 }
240 for (i = 0; i < vlen; i++, v++) {
241 const char *name = btf_str(btf, v->name_off);
242
243 if (json_output) {
244 jsonw_start_object(w);
245 jsonw_string_field(w, "name", name);
246 if (btf_kflag(t))
247 jsonw_int_field(w, "val", v->val);
248 else
249 jsonw_uint_field(w, "val", v->val);
250 jsonw_end_object(w);
251 } else {
252 if (btf_kflag(t))
253 printf("\n\t'%s' val=%d", name, v->val);
254 else
255 printf("\n\t'%s' val=%u", name, (__u32)v->val);
256 }
257 }
258 if (json_output)
259 jsonw_end_array(w);
260 break;
261 }
262 case BTF_KIND_ENUM64: {
263 const struct btf_enum64 *v = btf_enum64(t);
264 __u32 i, vlen = btf_vlen(t);
265 const char *encoding;
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_kflag(t) ? "union" : "struct";
304
305 if (json_output)
306 jsonw_string_field(w, "fwd_kind", fwd_kind);
307 else
308 printf(" fwd_kind=%s", fwd_kind);
309 break;
310 }
311 case BTF_KIND_FUNC: {
312 const char *linkage = btf_func_linkage_str(t);
313
314 if (json_output) {
315 jsonw_uint_field(w, "type_id", t->type);
316 jsonw_string_field(w, "linkage", linkage);
317 } else {
318 printf(" type_id=%u linkage=%s", t->type, linkage);
319 }
320 break;
321 }
322 case BTF_KIND_FUNC_PROTO: {
323 const struct btf_param *p = (const void *)(t + 1);
324 __u32 i, vlen = btf_vlen(t);
325
326 if (json_output) {
327 jsonw_uint_field(w, "ret_type_id", t->type);
328 jsonw_uint_field(w, "vlen", vlen);
329 jsonw_name(w, "params");
330 jsonw_start_array(w);
331 } else {
332 printf(" ret_type_id=%u vlen=%u", t->type, vlen);
333 }
334 for (i = 0; i < vlen; i++, p++) {
335 const char *name = btf_str(btf, p->name_off);
336
337 if (json_output) {
338 jsonw_start_object(w);
339 jsonw_string_field(w, "name", name);
340 jsonw_uint_field(w, "type_id", p->type);
341 jsonw_end_object(w);
342 } else {
343 printf("\n\t'%s' type_id=%u", name, p->type);
344 }
345 }
346 if (json_output)
347 jsonw_end_array(w);
348 break;
349 }
350 case BTF_KIND_VAR: {
351 const struct btf_var *v = (const void *)(t + 1);
352 const char *linkage;
353
354 linkage = btf_var_linkage_str(v->linkage);
355
356 if (json_output) {
357 jsonw_uint_field(w, "type_id", t->type);
358 jsonw_string_field(w, "linkage", linkage);
359 } else {
360 printf(" type_id=%u, linkage=%s", t->type, linkage);
361 }
362 break;
363 }
364 case BTF_KIND_DATASEC: {
365 const struct btf_var_secinfo *v = (const void *)(t + 1);
366 const struct btf_type *vt;
367 __u32 i, vlen = btf_vlen(t);
368
369 if (json_output) {
370 jsonw_uint_field(w, "size", t->size);
371 jsonw_uint_field(w, "vlen", vlen);
372 jsonw_name(w, "vars");
373 jsonw_start_array(w);
374 } else {
375 printf(" size=%u vlen=%u", t->size, vlen);
376 }
377 for (i = 0; i < vlen; i++, v++) {
378 if (json_output) {
379 jsonw_start_object(w);
380 jsonw_uint_field(w, "type_id", v->type);
381 jsonw_uint_field(w, "offset", v->offset);
382 jsonw_uint_field(w, "size", v->size);
383 jsonw_end_object(w);
384 } else {
385 printf("\n\ttype_id=%u offset=%u size=%u",
386 v->type, v->offset, v->size);
387
388 if (v->type < btf__type_cnt(btf)) {
389 vt = btf__type_by_id(btf, v->type);
390 printf(" (%s '%s')",
391 btf_kind_str[btf_kind_safe(btf_kind(vt))],
392 btf_str(btf, vt->name_off));
393 }
394 }
395 }
396 if (json_output)
397 jsonw_end_array(w);
398 break;
399 }
400 case BTF_KIND_FLOAT: {
401 if (json_output)
402 jsonw_uint_field(w, "size", t->size);
403 else
404 printf(" size=%u", t->size);
405 break;
406 }
407 case BTF_KIND_DECL_TAG: {
408 const struct btf_decl_tag *tag = (const void *)(t + 1);
409
410 if (json_output) {
411 jsonw_uint_field(w, "type_id", t->type);
412 jsonw_int_field(w, "component_idx", tag->component_idx);
413 } else {
414 printf(" type_id=%u component_idx=%d", t->type, tag->component_idx);
415 }
416 break;
417 }
418 default:
419 break;
420 }
421
422 if (json_output)
423 jsonw_end_object(json_wtr);
424 else
425 printf("\n");
426
427 return 0;
428 }
429
dump_btf_raw(const struct btf * btf,__u32 * root_type_ids,int root_type_cnt)430 static int dump_btf_raw(const struct btf *btf,
431 __u32 *root_type_ids, int root_type_cnt)
432 {
433 const struct btf_type *t;
434 int i;
435
436 if (json_output) {
437 jsonw_start_object(json_wtr);
438 jsonw_name(json_wtr, "types");
439 jsonw_start_array(json_wtr);
440 }
441
442 if (root_type_cnt) {
443 for (i = 0; i < root_type_cnt; i++) {
444 t = btf__type_by_id(btf, root_type_ids[i]);
445 dump_btf_type(btf, root_type_ids[i], t);
446 }
447 } else {
448 const struct btf *base;
449 int cnt = btf__type_cnt(btf);
450 int start_id = 1;
451
452 base = btf__base_btf(btf);
453 if (base)
454 start_id = btf__type_cnt(base);
455
456 for (i = start_id; i < cnt; i++) {
457 t = btf__type_by_id(btf, i);
458 dump_btf_type(btf, i, t);
459 }
460 }
461
462 if (json_output) {
463 jsonw_end_array(json_wtr);
464 jsonw_end_object(json_wtr);
465 }
466 return 0;
467 }
468
469 struct ptr_array {
470 __u32 cnt;
471 __u32 cap;
472 const void **elems;
473 };
474
ptr_array_push(const void * ptr,struct ptr_array * arr)475 static int ptr_array_push(const void *ptr, struct ptr_array *arr)
476 {
477 __u32 new_cap;
478 void *tmp;
479
480 if (arr->cnt == arr->cap) {
481 new_cap = (arr->cap ?: 16) * 2;
482 tmp = realloc(arr->elems, sizeof(*arr->elems) * new_cap);
483 if (!tmp)
484 return -ENOMEM;
485 arr->elems = tmp;
486 arr->cap = new_cap;
487 }
488 arr->elems[arr->cnt++] = ptr;
489 return 0;
490 }
491
ptr_array_free(struct ptr_array * arr)492 static void ptr_array_free(struct ptr_array *arr)
493 {
494 free(arr->elems);
495 }
496
cmp_kfuncs(const void * pa,const void * pb,void * ctx)497 static int cmp_kfuncs(const void *pa, const void *pb, void *ctx)
498 {
499 struct btf *btf = ctx;
500 const struct btf_type *a = *(void **)pa;
501 const struct btf_type *b = *(void **)pb;
502
503 return strcmp(btf__str_by_offset(btf, a->name_off),
504 btf__str_by_offset(btf, b->name_off));
505 }
506
dump_btf_kfuncs(struct btf_dump * d,const struct btf * btf)507 static int dump_btf_kfuncs(struct btf_dump *d, const struct btf *btf)
508 {
509 LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts);
510 __u32 cnt = btf__type_cnt(btf), i, j;
511 struct ptr_array fastcalls = {};
512 struct ptr_array kfuncs = {};
513 int err = 0;
514
515 printf("\n/* BPF kfuncs */\n");
516 printf("#ifndef BPF_NO_KFUNC_PROTOTYPES\n");
517
518 for (i = 1; i < cnt; i++) {
519 const struct btf_type *t = btf__type_by_id(btf, i);
520 const struct btf_type *ft;
521 const char *name;
522
523 if (!btf_is_decl_tag(t))
524 continue;
525
526 if (btf_decl_tag(t)->component_idx != -1)
527 continue;
528
529 ft = btf__type_by_id(btf, t->type);
530 if (!btf_is_func(ft))
531 continue;
532
533 name = btf__name_by_offset(btf, t->name_off);
534 if (strncmp(name, KFUNC_DECL_TAG, sizeof(KFUNC_DECL_TAG)) == 0) {
535 err = ptr_array_push(ft, &kfuncs);
536 if (err)
537 goto out;
538 }
539
540 if (strncmp(name, FASTCALL_DECL_TAG, sizeof(FASTCALL_DECL_TAG)) == 0) {
541 err = ptr_array_push(ft, &fastcalls);
542 if (err)
543 goto out;
544 }
545 }
546
547 /* Sort kfuncs by name for improved vmlinux.h stability */
548 qsort_r(kfuncs.elems, kfuncs.cnt, sizeof(*kfuncs.elems), cmp_kfuncs, (void *)btf);
549 for (i = 0; i < kfuncs.cnt; i++) {
550 const struct btf_type *t = kfuncs.elems[i];
551
552 printf("extern ");
553
554 /* Assume small amount of fastcall kfuncs */
555 for (j = 0; j < fastcalls.cnt; j++) {
556 if (fastcalls.elems[j] == t) {
557 printf("__bpf_fastcall ");
558 break;
559 }
560 }
561
562 opts.field_name = btf__name_by_offset(btf, t->name_off);
563 err = btf_dump__emit_type_decl(d, t->type, &opts);
564 if (err)
565 goto out;
566
567 printf(" __weak __ksym;\n");
568 }
569
570 printf("#endif\n\n");
571
572 out:
573 ptr_array_free(&fastcalls);
574 ptr_array_free(&kfuncs);
575 return err;
576 }
577
btf_dump_printf(void * ctx,const char * fmt,va_list args)578 static void __printf(2, 0) btf_dump_printf(void *ctx,
579 const char *fmt, va_list args)
580 {
581 vfprintf(stdout, fmt, args);
582 }
583
btf_type_rank(const struct btf * btf,__u32 index,bool has_name)584 static int btf_type_rank(const struct btf *btf, __u32 index, bool has_name)
585 {
586 const struct btf_type *t = btf__type_by_id(btf, index);
587 const int kind = btf_kind(t);
588 const int max_rank = 10;
589
590 if (t->name_off)
591 has_name = true;
592
593 switch (kind) {
594 case BTF_KIND_ENUM:
595 case BTF_KIND_ENUM64:
596 return has_name ? 1 : 0;
597 case BTF_KIND_INT:
598 case BTF_KIND_FLOAT:
599 return 2;
600 case BTF_KIND_STRUCT:
601 case BTF_KIND_UNION:
602 return has_name ? 3 : max_rank;
603 case BTF_KIND_FUNC_PROTO:
604 return has_name ? 4 : max_rank;
605 case BTF_KIND_ARRAY:
606 if (has_name)
607 return btf_type_rank(btf, btf_array(t)->type, has_name);
608 return max_rank;
609 case BTF_KIND_TYPE_TAG:
610 case BTF_KIND_CONST:
611 case BTF_KIND_PTR:
612 case BTF_KIND_VOLATILE:
613 case BTF_KIND_RESTRICT:
614 case BTF_KIND_TYPEDEF:
615 case BTF_KIND_DECL_TAG:
616 if (has_name)
617 return btf_type_rank(btf, t->type, has_name);
618 return max_rank;
619 default:
620 return max_rank;
621 }
622 }
623
btf_type_sort_name(const struct btf * btf,__u32 index,bool from_ref)624 static const char *btf_type_sort_name(const struct btf *btf, __u32 index, bool from_ref)
625 {
626 const struct btf_type *t = btf__type_by_id(btf, index);
627
628 switch (btf_kind(t)) {
629 case BTF_KIND_ENUM:
630 case BTF_KIND_ENUM64: {
631 int name_off = t->name_off;
632
633 if (!from_ref && !name_off && btf_vlen(t))
634 name_off = btf_kind(t) == BTF_KIND_ENUM64 ?
635 btf_enum64(t)->name_off :
636 btf_enum(t)->name_off;
637
638 return btf__name_by_offset(btf, name_off);
639 }
640 case BTF_KIND_ARRAY:
641 return btf_type_sort_name(btf, btf_array(t)->type, true);
642 case BTF_KIND_TYPE_TAG:
643 case BTF_KIND_CONST:
644 case BTF_KIND_PTR:
645 case BTF_KIND_VOLATILE:
646 case BTF_KIND_RESTRICT:
647 case BTF_KIND_TYPEDEF:
648 case BTF_KIND_DECL_TAG:
649 return btf_type_sort_name(btf, t->type, true);
650 default:
651 return btf__name_by_offset(btf, t->name_off);
652 }
653 return NULL;
654 }
655
hasher(__u64 hash,__u64 val)656 static __u64 hasher(__u64 hash, __u64 val)
657 {
658 return hash * 31 + val;
659 }
660
btf_name_hasher(__u64 hash,const struct btf * btf,__u32 name_off)661 static __u64 btf_name_hasher(__u64 hash, const struct btf *btf, __u32 name_off)
662 {
663 if (!name_off)
664 return hash;
665
666 return hasher(hash, str_hash(btf__name_by_offset(btf, name_off)));
667 }
668
btf_type_disambig_hash(const struct btf * btf,__u32 id,bool include_members)669 static __u64 btf_type_disambig_hash(const struct btf *btf, __u32 id, bool include_members)
670 {
671 const struct btf_type *t = btf__type_by_id(btf, id);
672 __u32 i;
673 size_t hash = 0;
674
675 hash = btf_name_hasher(hash, btf, t->name_off);
676
677 switch (btf_kind(t)) {
678 case BTF_KIND_ENUM:
679 case BTF_KIND_ENUM64:
680 for (i = 0; i < btf_vlen(t); i++) {
681 __u32 name_off = btf_is_enum(t) ?
682 btf_enum(t)[i].name_off :
683 btf_enum64(t)[i].name_off;
684
685 hash = btf_name_hasher(hash, btf, name_off);
686 }
687 break;
688 case BTF_KIND_STRUCT:
689 case BTF_KIND_UNION:
690 if (!include_members)
691 break;
692 for (i = 0; i < btf_vlen(t); i++) {
693 const struct btf_member *m = btf_members(t) + i;
694
695 hash = btf_name_hasher(hash, btf, m->name_off);
696 /* resolve field type's name and hash it as well */
697 hash = hasher(hash, btf_type_disambig_hash(btf, m->type, false));
698 }
699 break;
700 case BTF_KIND_TYPE_TAG:
701 case BTF_KIND_CONST:
702 case BTF_KIND_PTR:
703 case BTF_KIND_VOLATILE:
704 case BTF_KIND_RESTRICT:
705 case BTF_KIND_TYPEDEF:
706 case BTF_KIND_DECL_TAG:
707 hash = hasher(hash, btf_type_disambig_hash(btf, t->type, include_members));
708 break;
709 case BTF_KIND_ARRAY: {
710 struct btf_array *arr = btf_array(t);
711
712 hash = hasher(hash, arr->nelems);
713 hash = hasher(hash, btf_type_disambig_hash(btf, arr->type, include_members));
714 break;
715 }
716 default:
717 break;
718 }
719 return hash;
720 }
721
btf_type_compare(const void * left,const void * right)722 static int btf_type_compare(const void *left, const void *right)
723 {
724 const struct sort_datum *d1 = (const struct sort_datum *)left;
725 const struct sort_datum *d2 = (const struct sort_datum *)right;
726 int r;
727
728 r = d1->type_rank - d2->type_rank;
729 r = r ?: strcmp(d1->sort_name, d2->sort_name);
730 r = r ?: strcmp(d1->own_name, d2->own_name);
731 if (r)
732 return r;
733
734 if (d1->disambig_hash != d2->disambig_hash)
735 return d1->disambig_hash < d2->disambig_hash ? -1 : 1;
736
737 return d1->index - d2->index;
738 }
739
sort_btf_c(const struct btf * btf)740 static struct sort_datum *sort_btf_c(const struct btf *btf)
741 {
742 struct sort_datum *datums;
743 int n;
744
745 n = btf__type_cnt(btf);
746 datums = malloc(sizeof(struct sort_datum) * n);
747 if (!datums)
748 return NULL;
749
750 for (int i = 0; i < n; ++i) {
751 struct sort_datum *d = datums + i;
752 const struct btf_type *t = btf__type_by_id(btf, i);
753
754 d->index = i;
755 d->type_rank = btf_type_rank(btf, i, false);
756 d->sort_name = btf_type_sort_name(btf, i, false);
757 d->own_name = btf__name_by_offset(btf, t->name_off);
758 d->disambig_hash = btf_type_disambig_hash(btf, i, true);
759 }
760
761 qsort(datums, n, sizeof(struct sort_datum), btf_type_compare);
762
763 return datums;
764 }
765
dump_btf_c(const struct btf * btf,__u32 * root_type_ids,int root_type_cnt,bool sort_dump)766 static int dump_btf_c(const struct btf *btf,
767 __u32 *root_type_ids, int root_type_cnt, bool sort_dump)
768 {
769 struct sort_datum *datums = NULL;
770 struct btf_dump *d;
771 int err = 0, i;
772
773 d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
774 if (!d)
775 return -errno;
776
777 printf("#ifndef __VMLINUX_H__\n");
778 printf("#define __VMLINUX_H__\n");
779 printf("\n");
780 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
781 printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
782 printf("#endif\n\n");
783 printf("#ifndef __ksym\n");
784 printf("#define __ksym __attribute__((section(\".ksyms\")))\n");
785 printf("#endif\n\n");
786 printf("#ifndef __weak\n");
787 printf("#define __weak __attribute__((weak))\n");
788 printf("#endif\n\n");
789 printf("#ifndef __bpf_fastcall\n");
790 printf("#if __has_attribute(bpf_fastcall)\n");
791 printf("#define __bpf_fastcall __attribute__((bpf_fastcall))\n");
792 printf("#else\n");
793 printf("#define __bpf_fastcall\n");
794 printf("#endif\n");
795 printf("#endif\n\n");
796
797 if (root_type_cnt) {
798 for (i = 0; i < root_type_cnt; i++) {
799 err = btf_dump__dump_type(d, root_type_ids[i]);
800 if (err)
801 goto done;
802 }
803 } else {
804 int cnt = btf__type_cnt(btf);
805
806 if (sort_dump)
807 datums = sort_btf_c(btf);
808 for (i = 1; i < cnt; i++) {
809 int idx = datums ? datums[i].index : i;
810
811 err = btf_dump__dump_type(d, idx);
812 if (err)
813 goto done;
814 }
815
816 err = dump_btf_kfuncs(d, btf);
817 if (err)
818 goto done;
819 }
820
821 printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
822 printf("#pragma clang attribute pop\n");
823 printf("#endif\n");
824 printf("\n");
825 printf("#endif /* __VMLINUX_H__ */\n");
826
827 done:
828 free(datums);
829 btf_dump__free(d);
830 return err;
831 }
832
833 static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
834
get_vmlinux_btf_from_sysfs(void)835 static struct btf *get_vmlinux_btf_from_sysfs(void)
836 {
837 struct btf *base;
838
839 base = btf__parse(sysfs_vmlinux, NULL);
840 if (!base)
841 p_err("failed to parse vmlinux BTF at '%s': %d\n",
842 sysfs_vmlinux, -errno);
843
844 return base;
845 }
846
847 #define BTF_NAME_BUFF_LEN 64
848
btf_is_kernel_module(__u32 btf_id)849 static bool btf_is_kernel_module(__u32 btf_id)
850 {
851 struct bpf_btf_info btf_info = {};
852 char btf_name[BTF_NAME_BUFF_LEN];
853 int btf_fd;
854 __u32 len;
855 int err;
856
857 btf_fd = bpf_btf_get_fd_by_id(btf_id);
858 if (btf_fd < 0) {
859 p_err("can't get BTF object by id (%u): %s", btf_id, strerror(errno));
860 return false;
861 }
862
863 len = sizeof(btf_info);
864 btf_info.name = ptr_to_u64(btf_name);
865 btf_info.name_len = sizeof(btf_name);
866 err = bpf_btf_get_info_by_fd(btf_fd, &btf_info, &len);
867 close(btf_fd);
868 if (err) {
869 p_err("can't get BTF (ID %u) object info: %s", btf_id, strerror(errno));
870 return false;
871 }
872
873 return btf_info.kernel_btf && strncmp(btf_name, "vmlinux", sizeof(btf_name)) != 0;
874 }
875
merge_btf_files(const char ** files,int nr_files,struct btf * vmlinux_base)876 static struct btf *merge_btf_files(const char **files, int nr_files,
877 struct btf *vmlinux_base)
878 {
879 struct btf *combined, *mod;
880 int ret;
881
882 combined = btf__new_empty_split(vmlinux_base);
883 if (!combined) {
884 p_err("failed to create combined BTF: %s", strerror(errno));
885 return NULL;
886 }
887
888 for (int j = 0; j < nr_files; j++) {
889 mod = btf__parse_split(files[j], vmlinux_base);
890 if (!mod) {
891 p_err("failed to load BTF from %s: %s", files[j], strerror(errno));
892 btf__free(combined);
893 return NULL;
894 }
895
896 ret = btf__add_btf(combined, mod);
897 btf__free(mod);
898 if (ret < 0) {
899 p_err("failed to merge BTF from %s: %s", files[j], strerror(-ret));
900 btf__free(combined);
901 return NULL;
902 }
903 }
904
905 ret = btf__dedup(combined, NULL);
906 if (ret) {
907 p_err("failed to dedup combined BTF: %s", strerror(-ret));
908 btf__free(combined);
909 return NULL;
910 }
911
912 return combined;
913 }
914
do_dump(int argc,char ** argv)915 static int do_dump(int argc, char **argv)
916 {
917 bool dump_c = false, sort_dump_c = true;
918 struct btf *btf = NULL, *base = NULL;
919 __u32 root_type_ids[MAX_ROOT_IDS];
920 bool have_id_filtering;
921 int root_type_cnt = 0;
922 __u32 btf_id = -1;
923 const char *src;
924 int fd = -1;
925 int err = 0;
926 int i;
927
928 if (!REQ_ARGS(2)) {
929 usage();
930 return -1;
931 }
932 src = GET_ARG();
933 if (is_prefix(src, "map")) {
934 struct bpf_map_info info = {};
935 __u32 len = sizeof(info);
936
937 if (!REQ_ARGS(2)) {
938 usage();
939 return -1;
940 }
941
942 fd = map_parse_fd_and_info(&argc, &argv, &info, &len,
943 BPF_F_RDONLY);
944 if (fd < 0)
945 return -1;
946
947 btf_id = info.btf_id;
948 if (argc && is_prefix(*argv, "key")) {
949 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
950 NEXT_ARG();
951 } else if (argc && is_prefix(*argv, "value")) {
952 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
953 NEXT_ARG();
954 } else if (argc && is_prefix(*argv, "all")) {
955 NEXT_ARG();
956 } else if (argc && is_prefix(*argv, "kv")) {
957 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
958 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
959 NEXT_ARG();
960 } else {
961 root_type_ids[root_type_cnt++] = info.btf_key_type_id;
962 root_type_ids[root_type_cnt++] = info.btf_value_type_id;
963 }
964 } else if (is_prefix(src, "prog")) {
965 struct bpf_prog_info info = {};
966 __u32 len = sizeof(info);
967
968 if (!REQ_ARGS(2)) {
969 usage();
970 return -1;
971 }
972
973 fd = prog_parse_fd(&argc, &argv);
974 if (fd < 0)
975 return -1;
976
977 err = bpf_prog_get_info_by_fd(fd, &info, &len);
978 if (err) {
979 p_err("can't get prog info: %s", strerror(errno));
980 goto done;
981 }
982
983 btf_id = info.btf_id;
984 } else if (is_prefix(src, "id")) {
985 char *endptr;
986
987 btf_id = strtoul(*argv, &endptr, 0);
988 if (*endptr) {
989 p_err("can't parse %s as ID", *argv);
990 return -1;
991 }
992 NEXT_ARG();
993 } else if (is_prefix(src, "file")) {
994 const char sysfs_prefix[] = "/sys/kernel/btf/";
995 struct btf *vmlinux_base = base_btf;
996 const char *files[MAX_BTF_FILES];
997 int nr_files = 0;
998
999 /* First grab our argument, filtering out the sysfs_vmlinux. */
1000 if (strcmp(*argv, sysfs_vmlinux) != 0) {
1001 files[nr_files++] = *argv;
1002 } else {
1003 p_info("skipping %s (will be loaded as base)", *argv);
1004 }
1005 NEXT_ARG();
1006
1007 while (argc && is_prefix(*argv, "file")) {
1008 NEXT_ARG();
1009 if (!REQ_ARGS(1)) {
1010 err = -EINVAL;
1011 goto done;
1012 }
1013 /* Filter out any sysfs vmlinux entries. */
1014 if (strcmp(*argv, sysfs_vmlinux) == 0) {
1015 p_info("skipping %s (will be loaded as base)", *argv);
1016 NEXT_ARG();
1017 continue;
1018 }
1019 if (nr_files >= MAX_BTF_FILES) {
1020 p_err("too many BTF files (max %d)", MAX_BTF_FILES);
1021 err = -E2BIG;
1022 goto done;
1023 }
1024 files[nr_files++] = *argv;
1025 NEXT_ARG();
1026 }
1027
1028 /* Auto-detect vmlinux base if any file is from sysfs */
1029 if (!vmlinux_base) {
1030 for (int j = 0; j < nr_files; j++) {
1031 if (strncmp(files[j], sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0) {
1032 base = get_vmlinux_btf_from_sysfs();
1033 vmlinux_base = base;
1034 break;
1035 }
1036 }
1037 }
1038
1039 /* All files were the sysfs_vmlinux, handle it like we used to */
1040 if (nr_files == 0) {
1041 nr_files = 1;
1042 files[0] = sysfs_vmlinux;
1043 }
1044
1045 if (nr_files == 1) {
1046 btf = btf__parse_split(files[0], base ?: base_btf);
1047 if (!btf) {
1048 err = -errno;
1049 p_err("failed to load BTF from %s: %s", files[0], strerror(errno));
1050 goto done;
1051 }
1052 } else {
1053 if (!vmlinux_base) {
1054 p_err("base BTF is required when merging multiple BTF files; use -B/--base-btf or use sysfs paths");
1055 err = -EINVAL;
1056 goto done;
1057 }
1058
1059 btf = merge_btf_files(files, nr_files, vmlinux_base);
1060 if (!btf) {
1061 err = -errno;
1062 goto done;
1063 }
1064 }
1065 } else {
1066 err = -1;
1067 p_err("unrecognized BTF source specifier: '%s'", src);
1068 goto done;
1069 }
1070
1071 have_id_filtering = !!root_type_cnt;
1072
1073 while (argc) {
1074 if (is_prefix(*argv, "format")) {
1075 NEXT_ARG();
1076 if (argc < 1) {
1077 p_err("expecting value for 'format' option\n");
1078 err = -EINVAL;
1079 goto done;
1080 }
1081 if (strcmp(*argv, "c") == 0) {
1082 dump_c = true;
1083 } else if (strcmp(*argv, "raw") == 0) {
1084 dump_c = false;
1085 } else {
1086 p_err("unrecognized format specifier: '%s', possible values: raw, c",
1087 *argv);
1088 err = -EINVAL;
1089 goto done;
1090 }
1091 NEXT_ARG();
1092 } else if (is_prefix(*argv, "root_id")) {
1093 __u32 root_id;
1094 char *end;
1095
1096 if (have_id_filtering) {
1097 p_err("cannot use root_id with other type filtering");
1098 err = -EINVAL;
1099 goto done;
1100 } else if (root_type_cnt == MAX_ROOT_IDS) {
1101 p_err("only %d root_id are supported", MAX_ROOT_IDS);
1102 err = -E2BIG;
1103 goto done;
1104 }
1105
1106 NEXT_ARG();
1107 root_id = strtoul(*argv, &end, 0);
1108 if (*end) {
1109 err = -1;
1110 p_err("can't parse %s as root ID", *argv);
1111 goto done;
1112 }
1113 for (i = 0; i < root_type_cnt; i++) {
1114 if (root_type_ids[i] == root_id) {
1115 err = -EINVAL;
1116 p_err("duplicate root_id %u supplied", root_id);
1117 goto done;
1118 }
1119 }
1120 root_type_ids[root_type_cnt++] = root_id;
1121 NEXT_ARG();
1122 } else if (is_prefix(*argv, "unsorted")) {
1123 sort_dump_c = false;
1124 NEXT_ARG();
1125 } else {
1126 p_err("unrecognized option: '%s'", *argv);
1127 err = -EINVAL;
1128 goto done;
1129 }
1130 }
1131
1132 if (!btf) {
1133 if (!base_btf && btf_is_kernel_module(btf_id)) {
1134 p_info("Warning: valid base BTF was not specified with -B option, falling back to standard base BTF (%s)",
1135 sysfs_vmlinux);
1136 base_btf = get_vmlinux_btf_from_sysfs();
1137 }
1138
1139 btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
1140 if (!btf) {
1141 err = -errno;
1142 p_err("get btf by id (%u): %s", btf_id, strerror(errno));
1143 goto done;
1144 }
1145 }
1146
1147 /* Invalid root IDs causes half emitted boilerplate and then unclean
1148 * exit. It's an ugly user experience, so handle common error here.
1149 */
1150 for (i = 0; i < root_type_cnt; i++) {
1151 if (root_type_ids[i] >= btf__type_cnt(btf)) {
1152 err = -EINVAL;
1153 p_err("invalid root ID: %u", root_type_ids[i]);
1154 goto done;
1155 }
1156 }
1157
1158 if (dump_c) {
1159 if (json_output) {
1160 p_err("JSON output for C-syntax dump is not supported");
1161 err = -ENOTSUP;
1162 goto done;
1163 }
1164 err = dump_btf_c(btf, root_type_ids, root_type_cnt, sort_dump_c);
1165 } else {
1166 err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
1167 }
1168
1169 done:
1170 close(fd);
1171 btf__free(btf);
1172 btf__free(base);
1173 return err;
1174 }
1175
btf_parse_fd(int * argc,char *** argv)1176 static int btf_parse_fd(int *argc, char ***argv)
1177 {
1178 unsigned int id;
1179 char *endptr;
1180 int fd;
1181
1182 if (!is_prefix(*argv[0], "id")) {
1183 p_err("expected 'id', got: '%s'?", **argv);
1184 return -1;
1185 }
1186 NEXT_ARGP();
1187
1188 id = strtoul(**argv, &endptr, 0);
1189 if (*endptr) {
1190 p_err("can't parse %s as ID", **argv);
1191 return -1;
1192 }
1193 NEXT_ARGP();
1194
1195 fd = bpf_btf_get_fd_by_id(id);
1196 if (fd < 0)
1197 p_err("can't get BTF object by id (%u): %s",
1198 id, strerror(errno));
1199
1200 return fd;
1201 }
1202
1203 static int
build_btf_type_table(struct hashmap * tab,enum bpf_obj_type type,void * info,__u32 * len)1204 build_btf_type_table(struct hashmap *tab, enum bpf_obj_type type,
1205 void *info, __u32 *len)
1206 {
1207 static const char * const names[] = {
1208 [BPF_OBJ_UNKNOWN] = "unknown",
1209 [BPF_OBJ_PROG] = "prog",
1210 [BPF_OBJ_MAP] = "map",
1211 };
1212 LIBBPF_OPTS(bpf_get_fd_by_id_opts, opts_ro);
1213 __u32 btf_id, id = 0;
1214 int err;
1215 int fd;
1216
1217 opts_ro.open_flags = BPF_F_RDONLY;
1218
1219 while (true) {
1220 switch (type) {
1221 case BPF_OBJ_PROG:
1222 err = bpf_prog_get_next_id(id, &id);
1223 break;
1224 case BPF_OBJ_MAP:
1225 err = bpf_map_get_next_id(id, &id);
1226 break;
1227 default:
1228 err = -1;
1229 p_err("unexpected object type: %u", type);
1230 goto err_free;
1231 }
1232 if (err) {
1233 if (errno == ENOENT) {
1234 err = 0;
1235 break;
1236 }
1237 p_err("can't get next %s: %s%s", names[type],
1238 strerror(errno),
1239 errno == EINVAL ? " -- kernel too old?" : "");
1240 goto err_free;
1241 }
1242
1243 switch (type) {
1244 case BPF_OBJ_PROG:
1245 fd = bpf_prog_get_fd_by_id(id);
1246 break;
1247 case BPF_OBJ_MAP:
1248 fd = bpf_map_get_fd_by_id_opts(id, &opts_ro);
1249 break;
1250 default:
1251 err = -1;
1252 p_err("unexpected object type: %u", type);
1253 goto err_free;
1254 }
1255 if (fd < 0) {
1256 if (errno == ENOENT)
1257 continue;
1258 p_err("can't get %s by id (%u): %s", names[type], id,
1259 strerror(errno));
1260 err = -1;
1261 goto err_free;
1262 }
1263
1264 memset(info, 0, *len);
1265 if (type == BPF_OBJ_PROG)
1266 err = bpf_prog_get_info_by_fd(fd, info, len);
1267 else
1268 err = bpf_map_get_info_by_fd(fd, info, len);
1269 close(fd);
1270 if (err) {
1271 p_err("can't get %s info: %s", names[type],
1272 strerror(errno));
1273 goto err_free;
1274 }
1275
1276 switch (type) {
1277 case BPF_OBJ_PROG:
1278 btf_id = ((struct bpf_prog_info *)info)->btf_id;
1279 break;
1280 case BPF_OBJ_MAP:
1281 btf_id = ((struct bpf_map_info *)info)->btf_id;
1282 break;
1283 default:
1284 err = -1;
1285 p_err("unexpected object type: %u", type);
1286 goto err_free;
1287 }
1288 if (!btf_id)
1289 continue;
1290
1291 err = hashmap__append(tab, btf_id, id);
1292 if (err) {
1293 p_err("failed to append entry to hashmap for BTF ID %u, object ID %u: %s",
1294 btf_id, id, strerror(-err));
1295 goto err_free;
1296 }
1297 }
1298
1299 return 0;
1300
1301 err_free:
1302 hashmap__free(tab);
1303 return err;
1304 }
1305
1306 static int
build_btf_tables(struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1307 build_btf_tables(struct hashmap *btf_prog_table,
1308 struct hashmap *btf_map_table)
1309 {
1310 struct bpf_prog_info prog_info;
1311 __u32 prog_len = sizeof(prog_info);
1312 struct bpf_map_info map_info;
1313 __u32 map_len = sizeof(map_info);
1314 int err = 0;
1315
1316 err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
1317 &prog_len);
1318 if (err)
1319 return err;
1320
1321 err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
1322 &map_len);
1323 if (err) {
1324 hashmap__free(btf_prog_table);
1325 return err;
1326 }
1327
1328 return 0;
1329 }
1330
1331 static void
show_btf_plain(struct bpf_btf_info * info,int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1332 show_btf_plain(struct bpf_btf_info *info, int fd,
1333 struct hashmap *btf_prog_table,
1334 struct hashmap *btf_map_table)
1335 {
1336 struct hashmap_entry *entry;
1337 const char *name = u64_to_ptr(info->name);
1338 int n;
1339
1340 printf("%u: ", info->id);
1341 if (info->kernel_btf)
1342 printf("name [%s] ", name);
1343 else if (name && name[0])
1344 printf("name %s ", name);
1345 else
1346 printf("name <anon> ");
1347 printf("size %uB", info->btf_size);
1348
1349 n = 0;
1350 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1351 printf("%s%lu", n++ == 0 ? " prog_ids " : ",", (unsigned long)entry->value);
1352 }
1353
1354 n = 0;
1355 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1356 printf("%s%lu", n++ == 0 ? " map_ids " : ",", (unsigned long)entry->value);
1357 }
1358
1359 emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
1360
1361 printf("\n");
1362 }
1363
1364 static void
show_btf_json(struct bpf_btf_info * info,int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1365 show_btf_json(struct bpf_btf_info *info, int fd,
1366 struct hashmap *btf_prog_table,
1367 struct hashmap *btf_map_table)
1368 {
1369 struct hashmap_entry *entry;
1370 const char *name = u64_to_ptr(info->name);
1371
1372 jsonw_start_object(json_wtr); /* btf object */
1373 jsonw_uint_field(json_wtr, "id", info->id);
1374 jsonw_uint_field(json_wtr, "size", info->btf_size);
1375
1376 jsonw_name(json_wtr, "prog_ids");
1377 jsonw_start_array(json_wtr); /* prog_ids */
1378 hashmap__for_each_key_entry(btf_prog_table, entry, info->id) {
1379 jsonw_uint(json_wtr, entry->value);
1380 }
1381 jsonw_end_array(json_wtr); /* prog_ids */
1382
1383 jsonw_name(json_wtr, "map_ids");
1384 jsonw_start_array(json_wtr); /* map_ids */
1385 hashmap__for_each_key_entry(btf_map_table, entry, info->id) {
1386 jsonw_uint(json_wtr, entry->value);
1387 }
1388 jsonw_end_array(json_wtr); /* map_ids */
1389
1390 emit_obj_refs_json(refs_table, info->id, json_wtr); /* pids */
1391
1392 jsonw_bool_field(json_wtr, "kernel", info->kernel_btf);
1393
1394 if (name && name[0])
1395 jsonw_string_field(json_wtr, "name", name);
1396
1397 jsonw_end_object(json_wtr); /* btf object */
1398 }
1399
1400 static int
show_btf(int fd,struct hashmap * btf_prog_table,struct hashmap * btf_map_table)1401 show_btf(int fd, struct hashmap *btf_prog_table,
1402 struct hashmap *btf_map_table)
1403 {
1404 struct bpf_btf_info info;
1405 __u32 len = sizeof(info);
1406 char name[64];
1407 int err;
1408
1409 memset(&info, 0, sizeof(info));
1410 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1411 if (err) {
1412 p_err("can't get BTF object info: %s", strerror(errno));
1413 return -1;
1414 }
1415 /* if kernel support emitting BTF object name, pass name pointer */
1416 if (info.name_len) {
1417 memset(&info, 0, sizeof(info));
1418 info.name_len = sizeof(name);
1419 info.name = ptr_to_u64(name);
1420 len = sizeof(info);
1421
1422 err = bpf_btf_get_info_by_fd(fd, &info, &len);
1423 if (err) {
1424 p_err("can't get BTF object info: %s", strerror(errno));
1425 return -1;
1426 }
1427 }
1428
1429 if (json_output)
1430 show_btf_json(&info, fd, btf_prog_table, btf_map_table);
1431 else
1432 show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
1433
1434 return 0;
1435 }
1436
do_show(int argc,char ** argv)1437 static int do_show(int argc, char **argv)
1438 {
1439 struct hashmap *btf_prog_table;
1440 struct hashmap *btf_map_table;
1441 int err, fd = -1;
1442 __u32 id = 0;
1443
1444 if (argc == 2) {
1445 fd = btf_parse_fd(&argc, &argv);
1446 if (fd < 0)
1447 return -1;
1448 }
1449
1450 if (argc) {
1451 if (fd >= 0)
1452 close(fd);
1453 return BAD_ARG();
1454 }
1455
1456 btf_prog_table = hashmap__new(hash_fn_for_key_as_id,
1457 equal_fn_for_key_as_id, NULL);
1458 btf_map_table = hashmap__new(hash_fn_for_key_as_id,
1459 equal_fn_for_key_as_id, NULL);
1460 if (IS_ERR(btf_prog_table) || IS_ERR(btf_map_table)) {
1461 hashmap__free(btf_prog_table);
1462 hashmap__free(btf_map_table);
1463 if (fd >= 0)
1464 close(fd);
1465 p_err("failed to create hashmap for object references");
1466 return -1;
1467 }
1468 err = build_btf_tables(btf_prog_table, btf_map_table);
1469 if (err) {
1470 if (fd >= 0)
1471 close(fd);
1472 return err;
1473 }
1474 build_obj_refs_table(&refs_table, BPF_OBJ_BTF);
1475
1476 if (fd >= 0) {
1477 err = show_btf(fd, btf_prog_table, btf_map_table);
1478 close(fd);
1479 goto exit_free;
1480 }
1481
1482 if (json_output)
1483 jsonw_start_array(json_wtr); /* root array */
1484
1485 while (true) {
1486 err = bpf_btf_get_next_id(id, &id);
1487 if (err) {
1488 if (errno == ENOENT) {
1489 err = 0;
1490 break;
1491 }
1492 p_err("can't get next BTF object: %s%s",
1493 strerror(errno),
1494 errno == EINVAL ? " -- kernel too old?" : "");
1495 err = -1;
1496 break;
1497 }
1498
1499 fd = bpf_btf_get_fd_by_id(id);
1500 if (fd < 0) {
1501 if (errno == ENOENT)
1502 continue;
1503 p_err("can't get BTF object by id (%u): %s",
1504 id, strerror(errno));
1505 err = -1;
1506 break;
1507 }
1508
1509 err = show_btf(fd, btf_prog_table, btf_map_table);
1510 close(fd);
1511 if (err)
1512 break;
1513 }
1514
1515 if (json_output)
1516 jsonw_end_array(json_wtr); /* root array */
1517
1518 exit_free:
1519 hashmap__free(btf_prog_table);
1520 hashmap__free(btf_map_table);
1521 delete_obj_refs_table(refs_table);
1522
1523 return err;
1524 }
1525
do_help(int argc,char ** argv)1526 static int do_help(int argc, char **argv)
1527 {
1528 if (json_output) {
1529 jsonw_null(json_wtr);
1530 return 0;
1531 }
1532
1533 fprintf(stderr,
1534 "Usage: %1$s %2$s { show | list } [id BTF_ID]\n"
1535 " %1$s %2$s dump BTF_SRC [format FORMAT] [root_id ROOT_ID]\n"
1536 " %1$s %2$s help\n"
1537 "\n"
1538 " BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] |\n"
1539 " file FILE [file FILE]... }\n"
1540 " FORMAT := { raw | c [unsorted] }\n"
1541 " " HELP_SPEC_MAP "\n"
1542 " " HELP_SPEC_PROGRAM "\n"
1543 " " HELP_SPEC_OPTIONS " |\n"
1544 " {-B|--base-btf} }\n"
1545 "",
1546 bin_name, "btf");
1547
1548 return 0;
1549 }
1550
1551 static const struct cmd cmds[] = {
1552 { "show", do_show },
1553 { "list", do_show },
1554 { "help", do_help },
1555 { "dump", do_dump },
1556 { 0 }
1557 };
1558
do_btf(int argc,char ** argv)1559 int do_btf(int argc, char **argv)
1560 {
1561 return cmd_select(cmds, argc, argv, do_help);
1562 }
1563