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1// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2/* Copyright (c) 2018 Facebook */
3
4#include <endian.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <string.h>
8#include <fcntl.h>
9#include <unistd.h>
10#include <errno.h>
11#include <linux/err.h>
12#include <linux/btf.h>
13#include <gelf.h>
14#include "btf.h"
15#include "bpf.h"
16#include "libbpf.h"
17#include "libbpf_internal.h"
18#include "hashmap.h"
19
20#define BTF_MAX_NR_TYPES 0x7fffffff
21#define BTF_MAX_STR_OFFSET 0x7fffffff
22
23static struct btf_type btf_void;
24
25struct btf {
26 union {
27 struct btf_header *hdr;
28 void *data;
29 };
30 struct btf_type **types;
31 const char *strings;
32 void *nohdr_data;
33 __u32 nr_types;
34 __u32 types_size;
35 __u32 data_size;
36 int fd;
37};
38
39static inline __u64 ptr_to_u64(const void *ptr)
40{
41 return (__u64) (unsigned long) ptr;
42}
43
44static int btf_add_type(struct btf *btf, struct btf_type *t)
45{
46 if (btf->types_size - btf->nr_types < 2) {
47 struct btf_type **new_types;
48 __u32 expand_by, new_size;
49
50 if (btf->types_size == BTF_MAX_NR_TYPES)
51 return -E2BIG;
52
53 expand_by = max(btf->types_size >> 2, 16);
54 new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
55
56 new_types = realloc(btf->types, sizeof(*new_types) * new_size);
57 if (!new_types)
58 return -ENOMEM;
59
60 if (btf->nr_types == 0)
61 new_types[0] = &btf_void;
62
63 btf->types = new_types;
64 btf->types_size = new_size;
65 }
66
67 btf->types[++(btf->nr_types)] = t;
68
69 return 0;
70}
71
72static int btf_parse_hdr(struct btf *btf)
73{
74 const struct btf_header *hdr = btf->hdr;
75 __u32 meta_left;
76
77 if (btf->data_size < sizeof(struct btf_header)) {
78 pr_debug("BTF header not found\n");
79 return -EINVAL;
80 }
81
82 if (hdr->magic != BTF_MAGIC) {
83 pr_debug("Invalid BTF magic:%x\n", hdr->magic);
84 return -EINVAL;
85 }
86
87 if (hdr->version != BTF_VERSION) {
88 pr_debug("Unsupported BTF version:%u\n", hdr->version);
89 return -ENOTSUP;
90 }
91
92 if (hdr->flags) {
93 pr_debug("Unsupported BTF flags:%x\n", hdr->flags);
94 return -ENOTSUP;
95 }
96
97 meta_left = btf->data_size - sizeof(*hdr);
98 if (!meta_left) {
99 pr_debug("BTF has no data\n");
100 return -EINVAL;
101 }
102
103 if (meta_left < hdr->type_off) {
104 pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off);
105 return -EINVAL;
106 }
107
108 if (meta_left < hdr->str_off) {
109 pr_debug("Invalid BTF string section offset:%u\n", hdr->str_off);
110 return -EINVAL;
111 }
112
113 if (hdr->type_off >= hdr->str_off) {
114 pr_debug("BTF type section offset >= string section offset. No type?\n");
115 return -EINVAL;
116 }
117
118 if (hdr->type_off & 0x02) {
119 pr_debug("BTF type section is not aligned to 4 bytes\n");
120 return -EINVAL;
121 }
122
123 btf->nohdr_data = btf->hdr + 1;
124
125 return 0;
126}
127
128static int btf_parse_str_sec(struct btf *btf)
129{
130 const struct btf_header *hdr = btf->hdr;
131 const char *start = btf->nohdr_data + hdr->str_off;
132 const char *end = start + btf->hdr->str_len;
133
134 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||
135 start[0] || end[-1]) {
136 pr_debug("Invalid BTF string section\n");
137 return -EINVAL;
138 }
139
140 btf->strings = start;
141
142 return 0;
143}
144
145static int btf_type_size(struct btf_type *t)
146{
147 int base_size = sizeof(struct btf_type);
148 __u16 vlen = btf_vlen(t);
149
150 switch (btf_kind(t)) {
151 case BTF_KIND_FWD:
152 case BTF_KIND_CONST:
153 case BTF_KIND_VOLATILE:
154 case BTF_KIND_RESTRICT:
155 case BTF_KIND_PTR:
156 case BTF_KIND_TYPEDEF:
157 case BTF_KIND_FUNC:
158 return base_size;
159 case BTF_KIND_INT:
160 return base_size + sizeof(__u32);
161 case BTF_KIND_ENUM:
162 return base_size + vlen * sizeof(struct btf_enum);
163 case BTF_KIND_ARRAY:
164 return base_size + sizeof(struct btf_array);
165 case BTF_KIND_STRUCT:
166 case BTF_KIND_UNION:
167 return base_size + vlen * sizeof(struct btf_member);
168 case BTF_KIND_FUNC_PROTO:
169 return base_size + vlen * sizeof(struct btf_param);
170 case BTF_KIND_VAR:
171 return base_size + sizeof(struct btf_var);
172 case BTF_KIND_DATASEC:
173 return base_size + vlen * sizeof(struct btf_var_secinfo);
174 default:
175 pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
176 return -EINVAL;
177 }
178}
179
180static int btf_parse_type_sec(struct btf *btf)
181{
182 struct btf_header *hdr = btf->hdr;
183 void *nohdr_data = btf->nohdr_data;
184 void *next_type = nohdr_data + hdr->type_off;
185 void *end_type = nohdr_data + hdr->str_off;
186
187 while (next_type < end_type) {
188 struct btf_type *t = next_type;
189 int type_size;
190 int err;
191
192 type_size = btf_type_size(t);
193 if (type_size < 0)
194 return type_size;
195 next_type += type_size;
196 err = btf_add_type(btf, t);
197 if (err)
198 return err;
199 }
200
201 return 0;
202}
203
204__u32 btf__get_nr_types(const struct btf *btf)
205{
206 return btf->nr_types;
207}
208
209const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
210{
211 if (type_id > btf->nr_types)
212 return NULL;
213
214 return btf->types[type_id];
215}
216
217static bool btf_type_is_void(const struct btf_type *t)
218{
219 return t == &btf_void || btf_is_fwd(t);
220}
221
222static bool btf_type_is_void_or_null(const struct btf_type *t)
223{
224 return !t || btf_type_is_void(t);
225}
226
227#define MAX_RESOLVE_DEPTH 32
228
229__s64 btf__resolve_size(const struct btf *btf, __u32 type_id)
230{
231 const struct btf_array *array;
232 const struct btf_type *t;
233 __u32 nelems = 1;
234 __s64 size = -1;
235 int i;
236
237 t = btf__type_by_id(btf, type_id);
238 for (i = 0; i < MAX_RESOLVE_DEPTH && !btf_type_is_void_or_null(t);
239 i++) {
240 switch (btf_kind(t)) {
241 case BTF_KIND_INT:
242 case BTF_KIND_STRUCT:
243 case BTF_KIND_UNION:
244 case BTF_KIND_ENUM:
245 case BTF_KIND_DATASEC:
246 size = t->size;
247 goto done;
248 case BTF_KIND_PTR:
249 size = sizeof(void *);
250 goto done;
251 case BTF_KIND_TYPEDEF:
252 case BTF_KIND_VOLATILE:
253 case BTF_KIND_CONST:
254 case BTF_KIND_RESTRICT:
255 case BTF_KIND_VAR:
256 type_id = t->type;
257 break;
258 case BTF_KIND_ARRAY:
259 array = btf_array(t);
260 if (nelems && array->nelems > UINT32_MAX / nelems)
261 return -E2BIG;
262 nelems *= array->nelems;
263 type_id = array->type;
264 break;
265 default:
266 return -EINVAL;
267 }
268
269 t = btf__type_by_id(btf, type_id);
270 }
271
272 if (size < 0)
273 return -EINVAL;
274
275done:
276 if (nelems && size > UINT32_MAX / nelems)
277 return -E2BIG;
278
279 return nelems * size;
280}
281
282int btf__resolve_type(const struct btf *btf, __u32 type_id)
283{
284 const struct btf_type *t;
285 int depth = 0;
286
287 t = btf__type_by_id(btf, type_id);
288 while (depth < MAX_RESOLVE_DEPTH &&
289 !btf_type_is_void_or_null(t) &&
290 (btf_is_mod(t) || btf_is_typedef(t) || btf_is_var(t))) {
291 type_id = t->type;
292 t = btf__type_by_id(btf, type_id);
293 depth++;
294 }
295
296 if (depth == MAX_RESOLVE_DEPTH || btf_type_is_void_or_null(t))
297 return -EINVAL;
298
299 return type_id;
300}
301
302__s32 btf__find_by_name(const struct btf *btf, const char *type_name)
303{
304 __u32 i;
305
306 if (!strcmp(type_name, "void"))
307 return 0;
308
309 for (i = 1; i <= btf->nr_types; i++) {
310 const struct btf_type *t = btf->types[i];
311 const char *name = btf__name_by_offset(btf, t->name_off);
312
313 if (name && !strcmp(type_name, name))
314 return i;
315 }
316
317 return -ENOENT;
318}
319
320void btf__free(struct btf *btf)
321{
322 if (!btf)
323 return;
324
325 if (btf->fd != -1)
326 close(btf->fd);
327
328 free(btf->data);
329 free(btf->types);
330 free(btf);
331}
332
333struct btf *btf__new(__u8 *data, __u32 size)
334{
335 struct btf *btf;
336 int err;
337
338 btf = calloc(1, sizeof(struct btf));
339 if (!btf)
340 return ERR_PTR(-ENOMEM);
341
342 btf->fd = -1;
343
344 btf->data = malloc(size);
345 if (!btf->data) {
346 err = -ENOMEM;
347 goto done;
348 }
349
350 memcpy(btf->data, data, size);
351 btf->data_size = size;
352
353 err = btf_parse_hdr(btf);
354 if (err)
355 goto done;
356
357 err = btf_parse_str_sec(btf);
358 if (err)
359 goto done;
360
361 err = btf_parse_type_sec(btf);
362
363done:
364 if (err) {
365 btf__free(btf);
366 return ERR_PTR(err);
367 }
368
369 return btf;
370}
371
372static bool btf_check_endianness(const GElf_Ehdr *ehdr)
373{
374#if __BYTE_ORDER == __LITTLE_ENDIAN
375 return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
376#elif __BYTE_ORDER == __BIG_ENDIAN
377 return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
378#else
379# error "Unrecognized __BYTE_ORDER__"
380#endif
381}
382
383struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
384{
385 Elf_Data *btf_data = NULL, *btf_ext_data = NULL;
386 int err = 0, fd = -1, idx = 0;
387 struct btf *btf = NULL;
388 Elf_Scn *scn = NULL;
389 Elf *elf = NULL;
390 GElf_Ehdr ehdr;
391
392 if (elf_version(EV_CURRENT) == EV_NONE) {
393 pr_warning("failed to init libelf for %s\n", path);
394 return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
395 }
396
397 fd = open(path, O_RDONLY);
398 if (fd < 0) {
399 err = -errno;
400 pr_warning("failed to open %s: %s\n", path, strerror(errno));
401 return ERR_PTR(err);
402 }
403
404 err = -LIBBPF_ERRNO__FORMAT;
405
406 elf = elf_begin(fd, ELF_C_READ, NULL);
407 if (!elf) {
408 pr_warning("failed to open %s as ELF file\n", path);
409 goto done;
410 }
411 if (!gelf_getehdr(elf, &ehdr)) {
412 pr_warning("failed to get EHDR from %s\n", path);
413 goto done;
414 }
415 if (!btf_check_endianness(&ehdr)) {
416 pr_warning("non-native ELF endianness is not supported\n");
417 goto done;
418 }
419 if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
420 pr_warning("failed to get e_shstrndx from %s\n", path);
421 goto done;
422 }
423
424 while ((scn = elf_nextscn(elf, scn)) != NULL) {
425 GElf_Shdr sh;
426 char *name;
427
428 idx++;
429 if (gelf_getshdr(scn, &sh) != &sh) {
430 pr_warning("failed to get section(%d) header from %s\n",
431 idx, path);
432 goto done;
433 }
434 name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
435 if (!name) {
436 pr_warning("failed to get section(%d) name from %s\n",
437 idx, path);
438 goto done;
439 }
440 if (strcmp(name, BTF_ELF_SEC) == 0) {
441 btf_data = elf_getdata(scn, 0);
442 if (!btf_data) {
443 pr_warning("failed to get section(%d, %s) data from %s\n",
444 idx, name, path);
445 goto done;
446 }
447 continue;
448 } else if (btf_ext && strcmp(name, BTF_EXT_ELF_SEC) == 0) {
449 btf_ext_data = elf_getdata(scn, 0);
450 if (!btf_ext_data) {
451 pr_warning("failed to get section(%d, %s) data from %s\n",
452 idx, name, path);
453 goto done;
454 }
455 continue;
456 }
457 }
458
459 err = 0;
460
461 if (!btf_data) {
462 err = -ENOENT;
463 goto done;
464 }
465 btf = btf__new(btf_data->d_buf, btf_data->d_size);
466 if (IS_ERR(btf))
467 goto done;
468
469 if (btf_ext && btf_ext_data) {
470 *btf_ext = btf_ext__new(btf_ext_data->d_buf,
471 btf_ext_data->d_size);
472 if (IS_ERR(*btf_ext))
473 goto done;
474 } else if (btf_ext) {
475 *btf_ext = NULL;
476 }
477done:
478 if (elf)
479 elf_end(elf);
480 close(fd);
481
482 if (err)
483 return ERR_PTR(err);
484 /*
485 * btf is always parsed before btf_ext, so no need to clean up
486 * btf_ext, if btf loading failed
487 */
488 if (IS_ERR(btf))
489 return btf;
490 if (btf_ext && IS_ERR(*btf_ext)) {
491 btf__free(btf);
492 err = PTR_ERR(*btf_ext);
493 return ERR_PTR(err);
494 }
495 return btf;
496}
497
498static int compare_vsi_off(const void *_a, const void *_b)
499{
500 const struct btf_var_secinfo *a = _a;
501 const struct btf_var_secinfo *b = _b;
502
503 return a->offset - b->offset;
504}
505
506static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
507 struct btf_type *t)
508{
509 __u32 size = 0, off = 0, i, vars = btf_vlen(t);
510 const char *name = btf__name_by_offset(btf, t->name_off);
511 const struct btf_type *t_var;
512 struct btf_var_secinfo *vsi;
513 const struct btf_var *var;
514 int ret;
515
516 if (!name) {
517 pr_debug("No name found in string section for DATASEC kind.\n");
518 return -ENOENT;
519 }
520
521 ret = bpf_object__section_size(obj, name, &size);
522 if (ret || !size || (t->size && t->size != size)) {
523 pr_debug("Invalid size for section %s: %u bytes\n", name, size);
524 return -ENOENT;
525 }
526
527 t->size = size;
528
529 for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) {
530 t_var = btf__type_by_id(btf, vsi->type);
531 var = btf_var(t_var);
532
533 if (!btf_is_var(t_var)) {
534 pr_debug("Non-VAR type seen in section %s\n", name);
535 return -EINVAL;
536 }
537
538 if (var->linkage == BTF_VAR_STATIC)
539 continue;
540
541 name = btf__name_by_offset(btf, t_var->name_off);
542 if (!name) {
543 pr_debug("No name found in string section for VAR kind\n");
544 return -ENOENT;
545 }
546
547 ret = bpf_object__variable_offset(obj, name, &off);
548 if (ret) {
549 pr_debug("No offset found in symbol table for VAR %s\n",
550 name);
551 return -ENOENT;
552 }
553
554 vsi->offset = off;
555 }
556
557 qsort(t + 1, vars, sizeof(*vsi), compare_vsi_off);
558 return 0;
559}
560
561int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
562{
563 int err = 0;
564 __u32 i;
565
566 for (i = 1; i <= btf->nr_types; i++) {
567 struct btf_type *t = btf->types[i];
568
569 /* Loader needs to fix up some of the things compiler
570 * couldn't get its hands on while emitting BTF. This
571 * is section size and global variable offset. We use
572 * the info from the ELF itself for this purpose.
573 */
574 if (btf_is_datasec(t)) {
575 err = btf_fixup_datasec(obj, btf, t);
576 if (err)
577 break;
578 }
579 }
580
581 return err;
582}
583
584int btf__load(struct btf *btf)
585{
586 __u32 log_buf_size = BPF_LOG_BUF_SIZE;
587 char *log_buf = NULL;
588 int err = 0;
589
590 if (btf->fd >= 0)
591 return -EEXIST;
592
593 log_buf = malloc(log_buf_size);
594 if (!log_buf)
595 return -ENOMEM;
596
597 *log_buf = 0;
598
599 btf->fd = bpf_load_btf(btf->data, btf->data_size,
600 log_buf, log_buf_size, false);
601 if (btf->fd < 0) {
602 err = -errno;
603 pr_warning("Error loading BTF: %s(%d)\n", strerror(errno), errno);
604 if (*log_buf)
605 pr_warning("%s\n", log_buf);
606 goto done;
607 }
608
609done:
610 free(log_buf);
611 return err;
612}
613
614int btf__fd(const struct btf *btf)
615{
616 return btf->fd;
617}
618
619const void *btf__get_raw_data(const struct btf *btf, __u32 *size)
620{
621 *size = btf->data_size;
622 return btf->data;
623}
624
625const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
626{
627 if (offset < btf->hdr->str_len)
628 return &btf->strings[offset];
629 else
630 return NULL;
631}
632
633int btf__get_from_id(__u32 id, struct btf **btf)
634{
635 struct bpf_btf_info btf_info = { 0 };
636 __u32 len = sizeof(btf_info);
637 __u32 last_size;
638 int btf_fd;
639 void *ptr;
640 int err;
641
642 err = 0;
643 *btf = NULL;
644 btf_fd = bpf_btf_get_fd_by_id(id);
645 if (btf_fd < 0)
646 return 0;
647
648 /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
649 * let's start with a sane default - 4KiB here - and resize it only if
650 * bpf_obj_get_info_by_fd() needs a bigger buffer.
651 */
652 btf_info.btf_size = 4096;
653 last_size = btf_info.btf_size;
654 ptr = malloc(last_size);
655 if (!ptr) {
656 err = -ENOMEM;
657 goto exit_free;
658 }
659
660 memset(ptr, 0, last_size);
661 btf_info.btf = ptr_to_u64(ptr);
662 err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
663
664 if (!err && btf_info.btf_size > last_size) {
665 void *temp_ptr;
666
667 last_size = btf_info.btf_size;
668 temp_ptr = realloc(ptr, last_size);
669 if (!temp_ptr) {
670 err = -ENOMEM;
671 goto exit_free;
672 }
673 ptr = temp_ptr;
674 memset(ptr, 0, last_size);
675 btf_info.btf = ptr_to_u64(ptr);
676 err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
677 }
678
679 if (err || btf_info.btf_size > last_size) {
680 err = errno;
681 goto exit_free;
682 }
683
684 *btf = btf__new((__u8 *)(long)btf_info.btf, btf_info.btf_size);
685 if (IS_ERR(*btf)) {
686 err = PTR_ERR(*btf);
687 *btf = NULL;
688 }
689
690exit_free:
691 close(btf_fd);
692 free(ptr);
693
694 return err;
695}
696
697int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
698 __u32 expected_key_size, __u32 expected_value_size,
699 __u32 *key_type_id, __u32 *value_type_id)
700{
701 const struct btf_type *container_type;
702 const struct btf_member *key, *value;
703 const size_t max_name = 256;
704 char container_name[max_name];
705 __s64 key_size, value_size;
706 __s32 container_id;
707
708 if (snprintf(container_name, max_name, "____btf_map_%s", map_name) ==
709 max_name) {
710 pr_warning("map:%s length of '____btf_map_%s' is too long\n",
711 map_name, map_name);
712 return -EINVAL;
713 }
714
715 container_id = btf__find_by_name(btf, container_name);
716 if (container_id < 0) {
717 pr_debug("map:%s container_name:%s cannot be found in BTF. Missing BPF_ANNOTATE_KV_PAIR?\n",
718 map_name, container_name);
719 return container_id;
720 }
721
722 container_type = btf__type_by_id(btf, container_id);
723 if (!container_type) {
724 pr_warning("map:%s cannot find BTF type for container_id:%u\n",
725 map_name, container_id);
726 return -EINVAL;
727 }
728
729 if (!btf_is_struct(container_type) || btf_vlen(container_type) < 2) {
730 pr_warning("map:%s container_name:%s is an invalid container struct\n",
731 map_name, container_name);
732 return -EINVAL;
733 }
734
735 key = btf_members(container_type);
736 value = key + 1;
737
738 key_size = btf__resolve_size(btf, key->type);
739 if (key_size < 0) {
740 pr_warning("map:%s invalid BTF key_type_size\n", map_name);
741 return key_size;
742 }
743
744 if (expected_key_size != key_size) {
745 pr_warning("map:%s btf_key_type_size:%u != map_def_key_size:%u\n",
746 map_name, (__u32)key_size, expected_key_size);
747 return -EINVAL;
748 }
749
750 value_size = btf__resolve_size(btf, value->type);
751 if (value_size < 0) {
752 pr_warning("map:%s invalid BTF value_type_size\n", map_name);
753 return value_size;
754 }
755
756 if (expected_value_size != value_size) {
757 pr_warning("map:%s btf_value_type_size:%u != map_def_value_size:%u\n",
758 map_name, (__u32)value_size, expected_value_size);
759 return -EINVAL;
760 }
761
762 *key_type_id = key->type;
763 *value_type_id = value->type;
764
765 return 0;
766}
767
768struct btf_ext_sec_setup_param {
769 __u32 off;
770 __u32 len;
771 __u32 min_rec_size;
772 struct btf_ext_info *ext_info;
773 const char *desc;
774};
775
776static int btf_ext_setup_info(struct btf_ext *btf_ext,
777 struct btf_ext_sec_setup_param *ext_sec)
778{
779 const struct btf_ext_info_sec *sinfo;
780 struct btf_ext_info *ext_info;
781 __u32 info_left, record_size;
782 /* The start of the info sec (including the __u32 record_size). */
783 void *info;
784
785 if (ext_sec->len == 0)
786 return 0;
787
788 if (ext_sec->off & 0x03) {
789 pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
790 ext_sec->desc);
791 return -EINVAL;
792 }
793
794 info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
795 info_left = ext_sec->len;
796
797 if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
798 pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
799 ext_sec->desc, ext_sec->off, ext_sec->len);
800 return -EINVAL;
801 }
802
803 /* At least a record size */
804 if (info_left < sizeof(__u32)) {
805 pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
806 return -EINVAL;
807 }
808
809 /* The record size needs to meet the minimum standard */
810 record_size = *(__u32 *)info;
811 if (record_size < ext_sec->min_rec_size ||
812 record_size & 0x03) {
813 pr_debug("%s section in .BTF.ext has invalid record size %u\n",
814 ext_sec->desc, record_size);
815 return -EINVAL;
816 }
817
818 sinfo = info + sizeof(__u32);
819 info_left -= sizeof(__u32);
820
821 /* If no records, return failure now so .BTF.ext won't be used. */
822 if (!info_left) {
823 pr_debug("%s section in .BTF.ext has no records", ext_sec->desc);
824 return -EINVAL;
825 }
826
827 while (info_left) {
828 unsigned int sec_hdrlen = sizeof(struct btf_ext_info_sec);
829 __u64 total_record_size;
830 __u32 num_records;
831
832 if (info_left < sec_hdrlen) {
833 pr_debug("%s section header is not found in .BTF.ext\n",
834 ext_sec->desc);
835 return -EINVAL;
836 }
837
838 num_records = sinfo->num_info;
839 if (num_records == 0) {
840 pr_debug("%s section has incorrect num_records in .BTF.ext\n",
841 ext_sec->desc);
842 return -EINVAL;
843 }
844
845 total_record_size = sec_hdrlen +
846 (__u64)num_records * record_size;
847 if (info_left < total_record_size) {
848 pr_debug("%s section has incorrect num_records in .BTF.ext\n",
849 ext_sec->desc);
850 return -EINVAL;
851 }
852
853 info_left -= total_record_size;
854 sinfo = (void *)sinfo + total_record_size;
855 }
856
857 ext_info = ext_sec->ext_info;
858 ext_info->len = ext_sec->len - sizeof(__u32);
859 ext_info->rec_size = record_size;
860 ext_info->info = info + sizeof(__u32);
861
862 return 0;
863}
864
865static int btf_ext_setup_func_info(struct btf_ext *btf_ext)
866{
867 struct btf_ext_sec_setup_param param = {
868 .off = btf_ext->hdr->func_info_off,
869 .len = btf_ext->hdr->func_info_len,
870 .min_rec_size = sizeof(struct bpf_func_info_min),
871 .ext_info = &btf_ext->func_info,
872 .desc = "func_info"
873 };
874
875 return btf_ext_setup_info(btf_ext, ¶m);
876}
877
878static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
879{
880 struct btf_ext_sec_setup_param param = {
881 .off = btf_ext->hdr->line_info_off,
882 .len = btf_ext->hdr->line_info_len,
883 .min_rec_size = sizeof(struct bpf_line_info_min),
884 .ext_info = &btf_ext->line_info,
885 .desc = "line_info",
886 };
887
888 return btf_ext_setup_info(btf_ext, ¶m);
889}
890
891static int btf_ext_setup_offset_reloc(struct btf_ext *btf_ext)
892{
893 struct btf_ext_sec_setup_param param = {
894 .off = btf_ext->hdr->offset_reloc_off,
895 .len = btf_ext->hdr->offset_reloc_len,
896 .min_rec_size = sizeof(struct bpf_offset_reloc),
897 .ext_info = &btf_ext->offset_reloc_info,
898 .desc = "offset_reloc",
899 };
900
901 return btf_ext_setup_info(btf_ext, ¶m);
902}
903
904static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
905{
906 const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
907
908 if (data_size < offsetofend(struct btf_ext_header, hdr_len) ||
909 data_size < hdr->hdr_len) {
910 pr_debug("BTF.ext header not found");
911 return -EINVAL;
912 }
913
914 if (hdr->magic != BTF_MAGIC) {
915 pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
916 return -EINVAL;
917 }
918
919 if (hdr->version != BTF_VERSION) {
920 pr_debug("Unsupported BTF.ext version:%u\n", hdr->version);
921 return -ENOTSUP;
922 }
923
924 if (hdr->flags) {
925 pr_debug("Unsupported BTF.ext flags:%x\n", hdr->flags);
926 return -ENOTSUP;
927 }
928
929 if (data_size == hdr->hdr_len) {
930 pr_debug("BTF.ext has no data\n");
931 return -EINVAL;
932 }
933
934 return 0;
935}
936
937void btf_ext__free(struct btf_ext *btf_ext)
938{
939 if (!btf_ext)
940 return;
941 free(btf_ext->data);
942 free(btf_ext);
943}
944
945struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
946{
947 struct btf_ext *btf_ext;
948 int err;
949
950 err = btf_ext_parse_hdr(data, size);
951 if (err)
952 return ERR_PTR(err);
953
954 btf_ext = calloc(1, sizeof(struct btf_ext));
955 if (!btf_ext)
956 return ERR_PTR(-ENOMEM);
957
958 btf_ext->data_size = size;
959 btf_ext->data = malloc(size);
960 if (!btf_ext->data) {
961 err = -ENOMEM;
962 goto done;
963 }
964 memcpy(btf_ext->data, data, size);
965
966 if (btf_ext->hdr->hdr_len <
967 offsetofend(struct btf_ext_header, line_info_len))
968 goto done;
969 err = btf_ext_setup_func_info(btf_ext);
970 if (err)
971 goto done;
972
973 err = btf_ext_setup_line_info(btf_ext);
974 if (err)
975 goto done;
976
977 if (btf_ext->hdr->hdr_len <
978 offsetofend(struct btf_ext_header, offset_reloc_len))
979 goto done;
980 err = btf_ext_setup_offset_reloc(btf_ext);
981 if (err)
982 goto done;
983
984done:
985 if (err) {
986 btf_ext__free(btf_ext);
987 return ERR_PTR(err);
988 }
989
990 return btf_ext;
991}
992
993const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size)
994{
995 *size = btf_ext->data_size;
996 return btf_ext->data;
997}
998
999static int btf_ext_reloc_info(const struct btf *btf,
1000 const struct btf_ext_info *ext_info,
1001 const char *sec_name, __u32 insns_cnt,
1002 void **info, __u32 *cnt)
1003{
1004 __u32 sec_hdrlen = sizeof(struct btf_ext_info_sec);
1005 __u32 i, record_size, existing_len, records_len;
1006 struct btf_ext_info_sec *sinfo;
1007 const char *info_sec_name;
1008 __u64 remain_len;
1009 void *data;
1010
1011 record_size = ext_info->rec_size;
1012 sinfo = ext_info->info;
1013 remain_len = ext_info->len;
1014 while (remain_len > 0) {
1015 records_len = sinfo->num_info * record_size;
1016 info_sec_name = btf__name_by_offset(btf, sinfo->sec_name_off);
1017 if (strcmp(info_sec_name, sec_name)) {
1018 remain_len -= sec_hdrlen + records_len;
1019 sinfo = (void *)sinfo + sec_hdrlen + records_len;
1020 continue;
1021 }
1022
1023 existing_len = (*cnt) * record_size;
1024 data = realloc(*info, existing_len + records_len);
1025 if (!data)
1026 return -ENOMEM;
1027
1028 memcpy(data + existing_len, sinfo->data, records_len);
1029 /* adjust insn_off only, the rest data will be passed
1030 * to the kernel.
1031 */
1032 for (i = 0; i < sinfo->num_info; i++) {
1033 __u32 *insn_off;
1034
1035 insn_off = data + existing_len + (i * record_size);
1036 *insn_off = *insn_off / sizeof(struct bpf_insn) +
1037 insns_cnt;
1038 }
1039 *info = data;
1040 *cnt += sinfo->num_info;
1041 return 0;
1042 }
1043
1044 return -ENOENT;
1045}
1046
1047int btf_ext__reloc_func_info(const struct btf *btf,
1048 const struct btf_ext *btf_ext,
1049 const char *sec_name, __u32 insns_cnt,
1050 void **func_info, __u32 *cnt)
1051{
1052 return btf_ext_reloc_info(btf, &btf_ext->func_info, sec_name,
1053 insns_cnt, func_info, cnt);
1054}
1055
1056int btf_ext__reloc_line_info(const struct btf *btf,
1057 const struct btf_ext *btf_ext,
1058 const char *sec_name, __u32 insns_cnt,
1059 void **line_info, __u32 *cnt)
1060{
1061 return btf_ext_reloc_info(btf, &btf_ext->line_info, sec_name,
1062 insns_cnt, line_info, cnt);
1063}
1064
1065__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext)
1066{
1067 return btf_ext->func_info.rec_size;
1068}
1069
1070__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext)
1071{
1072 return btf_ext->line_info.rec_size;
1073}
1074
1075struct btf_dedup;
1076
1077static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
1078 const struct btf_dedup_opts *opts);
1079static void btf_dedup_free(struct btf_dedup *d);
1080static int btf_dedup_strings(struct btf_dedup *d);
1081static int btf_dedup_prim_types(struct btf_dedup *d);
1082static int btf_dedup_struct_types(struct btf_dedup *d);
1083static int btf_dedup_ref_types(struct btf_dedup *d);
1084static int btf_dedup_compact_types(struct btf_dedup *d);
1085static int btf_dedup_remap_types(struct btf_dedup *d);
1086
1087/*
1088 * Deduplicate BTF types and strings.
1089 *
1090 * BTF dedup algorithm takes as an input `struct btf` representing `.BTF` ELF
1091 * section with all BTF type descriptors and string data. It overwrites that
1092 * memory in-place with deduplicated types and strings without any loss of
1093 * information. If optional `struct btf_ext` representing '.BTF.ext' ELF section
1094 * is provided, all the strings referenced from .BTF.ext section are honored
1095 * and updated to point to the right offsets after deduplication.
1096 *
1097 * If function returns with error, type/string data might be garbled and should
1098 * be discarded.
1099 *
1100 * More verbose and detailed description of both problem btf_dedup is solving,
1101 * as well as solution could be found at:
1102 * https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html
1103 *
1104 * Problem description and justification
1105 * =====================================
1106 *
1107 * BTF type information is typically emitted either as a result of conversion
1108 * from DWARF to BTF or directly by compiler. In both cases, each compilation
1109 * unit contains information about a subset of all the types that are used
1110 * in an application. These subsets are frequently overlapping and contain a lot
1111 * of duplicated information when later concatenated together into a single
1112 * binary. This algorithm ensures that each unique type is represented by single
1113 * BTF type descriptor, greatly reducing resulting size of BTF data.
1114 *
1115 * Compilation unit isolation and subsequent duplication of data is not the only
1116 * problem. The same type hierarchy (e.g., struct and all the type that struct
1117 * references) in different compilation units can be represented in BTF to
1118 * various degrees of completeness (or, rather, incompleteness) due to
1119 * struct/union forward declarations.
1120 *
1121 * Let's take a look at an example, that we'll use to better understand the
1122 * problem (and solution). Suppose we have two compilation units, each using
1123 * same `struct S`, but each of them having incomplete type information about
1124 * struct's fields:
1125 *
1126 * // CU #1:
1127 * struct S;
1128 * struct A {
1129 * int a;
1130 * struct A* self;
1131 * struct S* parent;
1132 * };
1133 * struct B;
1134 * struct S {
1135 * struct A* a_ptr;
1136 * struct B* b_ptr;
1137 * };
1138 *
1139 * // CU #2:
1140 * struct S;
1141 * struct A;
1142 * struct B {
1143 * int b;
1144 * struct B* self;
1145 * struct S* parent;
1146 * };
1147 * struct S {
1148 * struct A* a_ptr;
1149 * struct B* b_ptr;
1150 * };
1151 *
1152 * In case of CU #1, BTF data will know only that `struct B` exist (but no
1153 * more), but will know the complete type information about `struct A`. While
1154 * for CU #2, it will know full type information about `struct B`, but will
1155 * only know about forward declaration of `struct A` (in BTF terms, it will
1156 * have `BTF_KIND_FWD` type descriptor with name `B`).
1157 *
1158 * This compilation unit isolation means that it's possible that there is no
1159 * single CU with complete type information describing structs `S`, `A`, and
1160 * `B`. Also, we might get tons of duplicated and redundant type information.
1161 *
1162 * Additional complication we need to keep in mind comes from the fact that
1163 * types, in general, can form graphs containing cycles, not just DAGs.
1164 *
1165 * While algorithm does deduplication, it also merges and resolves type
1166 * information (unless disabled throught `struct btf_opts`), whenever possible.
1167 * E.g., in the example above with two compilation units having partial type
1168 * information for structs `A` and `B`, the output of algorithm will emit
1169 * a single copy of each BTF type that describes structs `A`, `B`, and `S`
1170 * (as well as type information for `int` and pointers), as if they were defined
1171 * in a single compilation unit as:
1172 *
1173 * struct A {
1174 * int a;
1175 * struct A* self;
1176 * struct S* parent;
1177 * };
1178 * struct B {
1179 * int b;
1180 * struct B* self;
1181 * struct S* parent;
1182 * };
1183 * struct S {
1184 * struct A* a_ptr;
1185 * struct B* b_ptr;
1186 * };
1187 *
1188 * Algorithm summary
1189 * =================
1190 *
1191 * Algorithm completes its work in 6 separate passes:
1192 *
1193 * 1. Strings deduplication.
1194 * 2. Primitive types deduplication (int, enum, fwd).
1195 * 3. Struct/union types deduplication.
1196 * 4. Reference types deduplication (pointers, typedefs, arrays, funcs, func
1197 * protos, and const/volatile/restrict modifiers).
1198 * 5. Types compaction.
1199 * 6. Types remapping.
1200 *
1201 * Algorithm determines canonical type descriptor, which is a single
1202 * representative type for each truly unique type. This canonical type is the
1203 * one that will go into final deduplicated BTF type information. For
1204 * struct/unions, it is also the type that algorithm will merge additional type
1205 * information into (while resolving FWDs), as it discovers it from data in
1206 * other CUs. Each input BTF type eventually gets either mapped to itself, if
1207 * that type is canonical, or to some other type, if that type is equivalent
1208 * and was chosen as canonical representative. This mapping is stored in
1209 * `btf_dedup->map` array. This map is also used to record STRUCT/UNION that
1210 * FWD type got resolved to.
1211 *
1212 * To facilitate fast discovery of canonical types, we also maintain canonical
1213 * index (`btf_dedup->dedup_table`), which maps type descriptor's signature hash
1214 * (i.e., hashed kind, name, size, fields, etc) into a list of canonical types
1215 * that match that signature. With sufficiently good choice of type signature
1216 * hashing function, we can limit number of canonical types for each unique type
1217 * signature to a very small number, allowing to find canonical type for any
1218 * duplicated type very quickly.
1219 *
1220 * Struct/union deduplication is the most critical part and algorithm for
1221 * deduplicating structs/unions is described in greater details in comments for
1222 * `btf_dedup_is_equiv` function.
1223 */
1224int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
1225 const struct btf_dedup_opts *opts)
1226{
1227 struct btf_dedup *d = btf_dedup_new(btf, btf_ext, opts);
1228 int err;
1229
1230 if (IS_ERR(d)) {
1231 pr_debug("btf_dedup_new failed: %ld", PTR_ERR(d));
1232 return -EINVAL;
1233 }
1234
1235 err = btf_dedup_strings(d);
1236 if (err < 0) {
1237 pr_debug("btf_dedup_strings failed:%d\n", err);
1238 goto done;
1239 }
1240 err = btf_dedup_prim_types(d);
1241 if (err < 0) {
1242 pr_debug("btf_dedup_prim_types failed:%d\n", err);
1243 goto done;
1244 }
1245 err = btf_dedup_struct_types(d);
1246 if (err < 0) {
1247 pr_debug("btf_dedup_struct_types failed:%d\n", err);
1248 goto done;
1249 }
1250 err = btf_dedup_ref_types(d);
1251 if (err < 0) {
1252 pr_debug("btf_dedup_ref_types failed:%d\n", err);
1253 goto done;
1254 }
1255 err = btf_dedup_compact_types(d);
1256 if (err < 0) {
1257 pr_debug("btf_dedup_compact_types failed:%d\n", err);
1258 goto done;
1259 }
1260 err = btf_dedup_remap_types(d);
1261 if (err < 0) {
1262 pr_debug("btf_dedup_remap_types failed:%d\n", err);
1263 goto done;
1264 }
1265
1266done:
1267 btf_dedup_free(d);
1268 return err;
1269}
1270
1271#define BTF_UNPROCESSED_ID ((__u32)-1)
1272#define BTF_IN_PROGRESS_ID ((__u32)-2)
1273
1274struct btf_dedup {
1275 /* .BTF section to be deduped in-place */
1276 struct btf *btf;
1277 /*
1278 * Optional .BTF.ext section. When provided, any strings referenced
1279 * from it will be taken into account when deduping strings
1280 */
1281 struct btf_ext *btf_ext;
1282 /*
1283 * This is a map from any type's signature hash to a list of possible
1284 * canonical representative type candidates. Hash collisions are
1285 * ignored, so even types of various kinds can share same list of
1286 * candidates, which is fine because we rely on subsequent
1287 * btf_xxx_equal() checks to authoritatively verify type equality.
1288 */
1289 struct hashmap *dedup_table;
1290 /* Canonical types map */
1291 __u32 *map;
1292 /* Hypothetical mapping, used during type graph equivalence checks */
1293 __u32 *hypot_map;
1294 __u32 *hypot_list;
1295 size_t hypot_cnt;
1296 size_t hypot_cap;
1297 /* Various option modifying behavior of algorithm */
1298 struct btf_dedup_opts opts;
1299};
1300
1301struct btf_str_ptr {
1302 const char *str;
1303 __u32 new_off;
1304 bool used;
1305};
1306
1307struct btf_str_ptrs {
1308 struct btf_str_ptr *ptrs;
1309 const char *data;
1310 __u32 cnt;
1311 __u32 cap;
1312};
1313
1314static long hash_combine(long h, long value)
1315{
1316 return h * 31 + value;
1317}
1318
1319#define for_each_dedup_cand(d, node, hash) \
1320 hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash)
1321
1322static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id)
1323{
1324 return hashmap__append(d->dedup_table,
1325 (void *)hash, (void *)(long)type_id);
1326}
1327
1328static int btf_dedup_hypot_map_add(struct btf_dedup *d,
1329 __u32 from_id, __u32 to_id)
1330{
1331 if (d->hypot_cnt == d->hypot_cap) {
1332 __u32 *new_list;
1333
1334 d->hypot_cap += max(16, d->hypot_cap / 2);
1335 new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap);
1336 if (!new_list)
1337 return -ENOMEM;
1338 d->hypot_list = new_list;
1339 }
1340 d->hypot_list[d->hypot_cnt++] = from_id;
1341 d->hypot_map[from_id] = to_id;
1342 return 0;
1343}
1344
1345static void btf_dedup_clear_hypot_map(struct btf_dedup *d)
1346{
1347 int i;
1348
1349 for (i = 0; i < d->hypot_cnt; i++)
1350 d->hypot_map[d->hypot_list[i]] = BTF_UNPROCESSED_ID;
1351 d->hypot_cnt = 0;
1352}
1353
1354static void btf_dedup_free(struct btf_dedup *d)
1355{
1356 hashmap__free(d->dedup_table);
1357 d->dedup_table = NULL;
1358
1359 free(d->map);
1360 d->map = NULL;
1361
1362 free(d->hypot_map);
1363 d->hypot_map = NULL;
1364
1365 free(d->hypot_list);
1366 d->hypot_list = NULL;
1367
1368 free(d);
1369}
1370
1371static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx)
1372{
1373 return (size_t)key;
1374}
1375
1376static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx)
1377{
1378 return 0;
1379}
1380
1381static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx)
1382{
1383 return k1 == k2;
1384}
1385
1386static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
1387 const struct btf_dedup_opts *opts)
1388{
1389 struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup));
1390 hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn;
1391 int i, err = 0;
1392
1393 if (!d)
1394 return ERR_PTR(-ENOMEM);
1395
1396 d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds;
1397 /* dedup_table_size is now used only to force collisions in tests */
1398 if (opts && opts->dedup_table_size == 1)
1399 hash_fn = btf_dedup_collision_hash_fn;
1400
1401 d->btf = btf;
1402 d->btf_ext = btf_ext;
1403
1404 d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL);
1405 if (IS_ERR(d->dedup_table)) {
1406 err = PTR_ERR(d->dedup_table);
1407 d->dedup_table = NULL;
1408 goto done;
1409 }
1410
1411 d->map = malloc(sizeof(__u32) * (1 + btf->nr_types));
1412 if (!d->map) {
1413 err = -ENOMEM;
1414 goto done;
1415 }
1416 /* special BTF "void" type is made canonical immediately */
1417 d->map[0] = 0;
1418 for (i = 1; i <= btf->nr_types; i++) {
1419 struct btf_type *t = d->btf->types[i];
1420
1421 /* VAR and DATASEC are never deduped and are self-canonical */
1422 if (btf_is_var(t) || btf_is_datasec(t))
1423 d->map[i] = i;
1424 else
1425 d->map[i] = BTF_UNPROCESSED_ID;
1426 }
1427
1428 d->hypot_map = malloc(sizeof(__u32) * (1 + btf->nr_types));
1429 if (!d->hypot_map) {
1430 err = -ENOMEM;
1431 goto done;
1432 }
1433 for (i = 0; i <= btf->nr_types; i++)
1434 d->hypot_map[i] = BTF_UNPROCESSED_ID;
1435
1436done:
1437 if (err) {
1438 btf_dedup_free(d);
1439 return ERR_PTR(err);
1440 }
1441
1442 return d;
1443}
1444
1445typedef int (*str_off_fn_t)(__u32 *str_off_ptr, void *ctx);
1446
1447/*
1448 * Iterate over all possible places in .BTF and .BTF.ext that can reference
1449 * string and pass pointer to it to a provided callback `fn`.
1450 */
1451static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
1452{
1453 void *line_data_cur, *line_data_end;
1454 int i, j, r, rec_size;
1455 struct btf_type *t;
1456
1457 for (i = 1; i <= d->btf->nr_types; i++) {
1458 t = d->btf->types[i];
1459 r = fn(&t->name_off, ctx);
1460 if (r)
1461 return r;
1462
1463 switch (btf_kind(t)) {
1464 case BTF_KIND_STRUCT:
1465 case BTF_KIND_UNION: {
1466 struct btf_member *m = btf_members(t);
1467 __u16 vlen = btf_vlen(t);
1468
1469 for (j = 0; j < vlen; j++) {
1470 r = fn(&m->name_off, ctx);
1471 if (r)
1472 return r;
1473 m++;
1474 }
1475 break;
1476 }
1477 case BTF_KIND_ENUM: {
1478 struct btf_enum *m = btf_enum(t);
1479 __u16 vlen = btf_vlen(t);
1480
1481 for (j = 0; j < vlen; j++) {
1482 r = fn(&m->name_off, ctx);
1483 if (r)
1484 return r;
1485 m++;
1486 }
1487 break;
1488 }
1489 case BTF_KIND_FUNC_PROTO: {
1490 struct btf_param *m = btf_params(t);
1491 __u16 vlen = btf_vlen(t);
1492
1493 for (j = 0; j < vlen; j++) {
1494 r = fn(&m->name_off, ctx);
1495 if (r)
1496 return r;
1497 m++;
1498 }
1499 break;
1500 }
1501 default:
1502 break;
1503 }
1504 }
1505
1506 if (!d->btf_ext)
1507 return 0;
1508
1509 line_data_cur = d->btf_ext->line_info.info;
1510 line_data_end = d->btf_ext->line_info.info + d->btf_ext->line_info.len;
1511 rec_size = d->btf_ext->line_info.rec_size;
1512
1513 while (line_data_cur < line_data_end) {
1514 struct btf_ext_info_sec *sec = line_data_cur;
1515 struct bpf_line_info_min *line_info;
1516 __u32 num_info = sec->num_info;
1517
1518 r = fn(&sec->sec_name_off, ctx);
1519 if (r)
1520 return r;
1521
1522 line_data_cur += sizeof(struct btf_ext_info_sec);
1523 for (i = 0; i < num_info; i++) {
1524 line_info = line_data_cur;
1525 r = fn(&line_info->file_name_off, ctx);
1526 if (r)
1527 return r;
1528 r = fn(&line_info->line_off, ctx);
1529 if (r)
1530 return r;
1531 line_data_cur += rec_size;
1532 }
1533 }
1534
1535 return 0;
1536}
1537
1538static int str_sort_by_content(const void *a1, const void *a2)
1539{
1540 const struct btf_str_ptr *p1 = a1;
1541 const struct btf_str_ptr *p2 = a2;
1542
1543 return strcmp(p1->str, p2->str);
1544}
1545
1546static int str_sort_by_offset(const void *a1, const void *a2)
1547{
1548 const struct btf_str_ptr *p1 = a1;
1549 const struct btf_str_ptr *p2 = a2;
1550
1551 if (p1->str != p2->str)
1552 return p1->str < p2->str ? -1 : 1;
1553 return 0;
1554}
1555
1556static int btf_dedup_str_ptr_cmp(const void *str_ptr, const void *pelem)
1557{
1558 const struct btf_str_ptr *p = pelem;
1559
1560 if (str_ptr != p->str)
1561 return (const char *)str_ptr < p->str ? -1 : 1;
1562 return 0;
1563}
1564
1565static int btf_str_mark_as_used(__u32 *str_off_ptr, void *ctx)
1566{
1567 struct btf_str_ptrs *strs;
1568 struct btf_str_ptr *s;
1569
1570 if (*str_off_ptr == 0)
1571 return 0;
1572
1573 strs = ctx;
1574 s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
1575 sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
1576 if (!s)
1577 return -EINVAL;
1578 s->used = true;
1579 return 0;
1580}
1581
1582static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx)
1583{
1584 struct btf_str_ptrs *strs;
1585 struct btf_str_ptr *s;
1586
1587 if (*str_off_ptr == 0)
1588 return 0;
1589
1590 strs = ctx;
1591 s = bsearch(strs->data + *str_off_ptr, strs->ptrs, strs->cnt,
1592 sizeof(struct btf_str_ptr), btf_dedup_str_ptr_cmp);
1593 if (!s)
1594 return -EINVAL;
1595 *str_off_ptr = s->new_off;
1596 return 0;
1597}
1598
1599/*
1600 * Dedup string and filter out those that are not referenced from either .BTF
1601 * or .BTF.ext (if provided) sections.
1602 *
1603 * This is done by building index of all strings in BTF's string section,
1604 * then iterating over all entities that can reference strings (e.g., type
1605 * names, struct field names, .BTF.ext line info, etc) and marking corresponding
1606 * strings as used. After that all used strings are deduped and compacted into
1607 * sequential blob of memory and new offsets are calculated. Then all the string
1608 * references are iterated again and rewritten using new offsets.
1609 */
1610static int btf_dedup_strings(struct btf_dedup *d)
1611{
1612 const struct btf_header *hdr = d->btf->hdr;
1613 char *start = (char *)d->btf->nohdr_data + hdr->str_off;
1614 char *end = start + d->btf->hdr->str_len;
1615 char *p = start, *tmp_strs = NULL;
1616 struct btf_str_ptrs strs = {
1617 .cnt = 0,
1618 .cap = 0,
1619 .ptrs = NULL,
1620 .data = start,
1621 };
1622 int i, j, err = 0, grp_idx;
1623 bool grp_used;
1624
1625 /* build index of all strings */
1626 while (p < end) {
1627 if (strs.cnt + 1 > strs.cap) {
1628 struct btf_str_ptr *new_ptrs;
1629
1630 strs.cap += max(strs.cnt / 2, 16);
1631 new_ptrs = realloc(strs.ptrs,
1632 sizeof(strs.ptrs[0]) * strs.cap);
1633 if (!new_ptrs) {
1634 err = -ENOMEM;
1635 goto done;
1636 }
1637 strs.ptrs = new_ptrs;
1638 }
1639
1640 strs.ptrs[strs.cnt].str = p;
1641 strs.ptrs[strs.cnt].used = false;
1642
1643 p += strlen(p) + 1;
1644 strs.cnt++;
1645 }
1646
1647 /* temporary storage for deduplicated strings */
1648 tmp_strs = malloc(d->btf->hdr->str_len);
1649 if (!tmp_strs) {
1650 err = -ENOMEM;
1651 goto done;
1652 }
1653
1654 /* mark all used strings */
1655 strs.ptrs[0].used = true;
1656 err = btf_for_each_str_off(d, btf_str_mark_as_used, &strs);
1657 if (err)
1658 goto done;
1659
1660 /* sort strings by context, so that we can identify duplicates */
1661 qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_content);
1662
1663 /*
1664 * iterate groups of equal strings and if any instance in a group was
1665 * referenced, emit single instance and remember new offset
1666 */
1667 p = tmp_strs;
1668 grp_idx = 0;
1669 grp_used = strs.ptrs[0].used;
1670 /* iterate past end to avoid code duplication after loop */
1671 for (i = 1; i <= strs.cnt; i++) {
1672 /*
1673 * when i == strs.cnt, we want to skip string comparison and go
1674 * straight to handling last group of strings (otherwise we'd
1675 * need to handle last group after the loop w/ duplicated code)
1676 */
1677 if (i < strs.cnt &&
1678 !strcmp(strs.ptrs[i].str, strs.ptrs[grp_idx].str)) {
1679 grp_used = grp_used || strs.ptrs[i].used;
1680 continue;
1681 }
1682
1683 /*
1684 * this check would have been required after the loop to handle
1685 * last group of strings, but due to <= condition in a loop
1686 * we avoid that duplication
1687 */
1688 if (grp_used) {
1689 int new_off = p - tmp_strs;
1690 __u32 len = strlen(strs.ptrs[grp_idx].str);
1691
1692 memmove(p, strs.ptrs[grp_idx].str, len + 1);
1693 for (j = grp_idx; j < i; j++)
1694 strs.ptrs[j].new_off = new_off;
1695 p += len + 1;
1696 }
1697
1698 if (i < strs.cnt) {
1699 grp_idx = i;
1700 grp_used = strs.ptrs[i].used;
1701 }
1702 }
1703
1704 /* replace original strings with deduped ones */
1705 d->btf->hdr->str_len = p - tmp_strs;
1706 memmove(start, tmp_strs, d->btf->hdr->str_len);
1707 end = start + d->btf->hdr->str_len;
1708
1709 /* restore original order for further binary search lookups */
1710 qsort(strs.ptrs, strs.cnt, sizeof(strs.ptrs[0]), str_sort_by_offset);
1711
1712 /* remap string offsets */
1713 err = btf_for_each_str_off(d, btf_str_remap_offset, &strs);
1714 if (err)
1715 goto done;
1716
1717 d->btf->hdr->str_len = end - start;
1718
1719done:
1720 free(tmp_strs);
1721 free(strs.ptrs);
1722 return err;
1723}
1724
1725static long btf_hash_common(struct btf_type *t)
1726{
1727 long h;
1728
1729 h = hash_combine(0, t->name_off);
1730 h = hash_combine(h, t->info);
1731 h = hash_combine(h, t->size);
1732 return h;
1733}
1734
1735static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2)
1736{
1737 return t1->name_off == t2->name_off &&
1738 t1->info == t2->info &&
1739 t1->size == t2->size;
1740}
1741
1742/* Calculate type signature hash of INT. */
1743static long btf_hash_int(struct btf_type *t)
1744{
1745 __u32 info = *(__u32 *)(t + 1);
1746 long h;
1747
1748 h = btf_hash_common(t);
1749 h = hash_combine(h, info);
1750 return h;
1751}
1752
1753/* Check structural equality of two INTs. */
1754static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2)
1755{
1756 __u32 info1, info2;
1757
1758 if (!btf_equal_common(t1, t2))
1759 return false;
1760 info1 = *(__u32 *)(t1 + 1);
1761 info2 = *(__u32 *)(t2 + 1);
1762 return info1 == info2;
1763}
1764
1765/* Calculate type signature hash of ENUM. */
1766static long btf_hash_enum(struct btf_type *t)
1767{
1768 long h;
1769
1770 /* don't hash vlen and enum members to support enum fwd resolving */
1771 h = hash_combine(0, t->name_off);
1772 h = hash_combine(h, t->info & ~0xffff);
1773 h = hash_combine(h, t->size);
1774 return h;
1775}
1776
1777/* Check structural equality of two ENUMs. */
1778static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
1779{
1780 const struct btf_enum *m1, *m2;
1781 __u16 vlen;
1782 int i;
1783
1784 if (!btf_equal_common(t1, t2))
1785 return false;
1786
1787 vlen = btf_vlen(t1);
1788 m1 = btf_enum(t1);
1789 m2 = btf_enum(t2);
1790 for (i = 0; i < vlen; i++) {
1791 if (m1->name_off != m2->name_off || m1->val != m2->val)
1792 return false;
1793 m1++;
1794 m2++;
1795 }
1796 return true;
1797}
1798
1799static inline bool btf_is_enum_fwd(struct btf_type *t)
1800{
1801 return btf_is_enum(t) && btf_vlen(t) == 0;
1802}
1803
1804static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
1805{
1806 if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
1807 return btf_equal_enum(t1, t2);
1808 /* ignore vlen when comparing */
1809 return t1->name_off == t2->name_off &&
1810 (t1->info & ~0xffff) == (t2->info & ~0xffff) &&
1811 t1->size == t2->size;
1812}
1813
1814/*
1815 * Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
1816 * as referenced type IDs equivalence is established separately during type
1817 * graph equivalence check algorithm.
1818 */
1819static long btf_hash_struct(struct btf_type *t)
1820{
1821 const struct btf_member *member = btf_members(t);
1822 __u32 vlen = btf_vlen(t);
1823 long h = btf_hash_common(t);
1824 int i;
1825
1826 for (i = 0; i < vlen; i++) {
1827 h = hash_combine(h, member->name_off);
1828 h = hash_combine(h, member->offset);
1829 /* no hashing of referenced type ID, it can be unresolved yet */
1830 member++;
1831 }
1832 return h;
1833}
1834
1835/*
1836 * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
1837 * IDs. This check is performed during type graph equivalence check and
1838 * referenced types equivalence is checked separately.
1839 */
1840static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2)
1841{
1842 const struct btf_member *m1, *m2;
1843 __u16 vlen;
1844 int i;
1845
1846 if (!btf_equal_common(t1, t2))
1847 return false;
1848
1849 vlen = btf_vlen(t1);
1850 m1 = btf_members(t1);
1851 m2 = btf_members(t2);
1852 for (i = 0; i < vlen; i++) {
1853 if (m1->name_off != m2->name_off || m1->offset != m2->offset)
1854 return false;
1855 m1++;
1856 m2++;
1857 }
1858 return true;
1859}
1860
1861/*
1862 * Calculate type signature hash of ARRAY, including referenced type IDs,
1863 * under assumption that they were already resolved to canonical type IDs and
1864 * are not going to change.
1865 */
1866static long btf_hash_array(struct btf_type *t)
1867{
1868 const struct btf_array *info = btf_array(t);
1869 long h = btf_hash_common(t);
1870
1871 h = hash_combine(h, info->type);
1872 h = hash_combine(h, info->index_type);
1873 h = hash_combine(h, info->nelems);
1874 return h;
1875}
1876
1877/*
1878 * Check exact equality of two ARRAYs, taking into account referenced
1879 * type IDs, under assumption that they were already resolved to canonical
1880 * type IDs and are not going to change.
1881 * This function is called during reference types deduplication to compare
1882 * ARRAY to potential canonical representative.
1883 */
1884static bool btf_equal_array(struct btf_type *t1, struct btf_type *t2)
1885{
1886 const struct btf_array *info1, *info2;
1887
1888 if (!btf_equal_common(t1, t2))
1889 return false;
1890
1891 info1 = btf_array(t1);
1892 info2 = btf_array(t2);
1893 return info1->type == info2->type &&
1894 info1->index_type == info2->index_type &&
1895 info1->nelems == info2->nelems;
1896}
1897
1898/*
1899 * Check structural compatibility of two ARRAYs, ignoring referenced type
1900 * IDs. This check is performed during type graph equivalence check and
1901 * referenced types equivalence is checked separately.
1902 */
1903static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2)
1904{
1905 if (!btf_equal_common(t1, t2))
1906 return false;
1907
1908 return btf_array(t1)->nelems == btf_array(t2)->nelems;
1909}
1910
1911/*
1912 * Calculate type signature hash of FUNC_PROTO, including referenced type IDs,
1913 * under assumption that they were already resolved to canonical type IDs and
1914 * are not going to change.
1915 */
1916static long btf_hash_fnproto(struct btf_type *t)
1917{
1918 const struct btf_param *member = btf_params(t);
1919 __u16 vlen = btf_vlen(t);
1920 long h = btf_hash_common(t);
1921 int i;
1922
1923 for (i = 0; i < vlen; i++) {
1924 h = hash_combine(h, member->name_off);
1925 h = hash_combine(h, member->type);
1926 member++;
1927 }
1928 return h;
1929}
1930
1931/*
1932 * Check exact equality of two FUNC_PROTOs, taking into account referenced
1933 * type IDs, under assumption that they were already resolved to canonical
1934 * type IDs and are not going to change.
1935 * This function is called during reference types deduplication to compare
1936 * FUNC_PROTO to potential canonical representative.
1937 */
1938static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2)
1939{
1940 const struct btf_param *m1, *m2;
1941 __u16 vlen;
1942 int i;
1943
1944 if (!btf_equal_common(t1, t2))
1945 return false;
1946
1947 vlen = btf_vlen(t1);
1948 m1 = btf_params(t1);
1949 m2 = btf_params(t2);
1950 for (i = 0; i < vlen; i++) {
1951 if (m1->name_off != m2->name_off || m1->type != m2->type)
1952 return false;
1953 m1++;
1954 m2++;
1955 }
1956 return true;
1957}
1958
1959/*
1960 * Check structural compatibility of two FUNC_PROTOs, ignoring referenced type
1961 * IDs. This check is performed during type graph equivalence check and
1962 * referenced types equivalence is checked separately.
1963 */
1964static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
1965{
1966 const struct btf_param *m1, *m2;
1967 __u16 vlen;
1968 int i;
1969
1970 /* skip return type ID */
1971 if (t1->name_off != t2->name_off || t1->info != t2->info)
1972 return false;
1973
1974 vlen = btf_vlen(t1);
1975 m1 = btf_params(t1);
1976 m2 = btf_params(t2);
1977 for (i = 0; i < vlen; i++) {
1978 if (m1->name_off != m2->name_off)
1979 return false;
1980 m1++;
1981 m2++;
1982 }
1983 return true;
1984}
1985
1986/*
1987 * Deduplicate primitive types, that can't reference other types, by calculating
1988 * their type signature hash and comparing them with any possible canonical
1989 * candidate. If no canonical candidate matches, type itself is marked as
1990 * canonical and is added into `btf_dedup->dedup_table` as another candidate.
1991 */
1992static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
1993{
1994 struct btf_type *t = d->btf->types[type_id];
1995 struct hashmap_entry *hash_entry;
1996 struct btf_type *cand;
1997 /* if we don't find equivalent type, then we are canonical */
1998 __u32 new_id = type_id;
1999 __u32 cand_id;
2000 long h;
2001
2002 switch (btf_kind(t)) {
2003 case BTF_KIND_CONST:
2004 case BTF_KIND_VOLATILE:
2005 case BTF_KIND_RESTRICT:
2006 case BTF_KIND_PTR:
2007 case BTF_KIND_TYPEDEF:
2008 case BTF_KIND_ARRAY:
2009 case BTF_KIND_STRUCT:
2010 case BTF_KIND_UNION:
2011 case BTF_KIND_FUNC:
2012 case BTF_KIND_FUNC_PROTO:
2013 case BTF_KIND_VAR:
2014 case BTF_KIND_DATASEC:
2015 return 0;
2016
2017 case BTF_KIND_INT:
2018 h = btf_hash_int(t);
2019 for_each_dedup_cand(d, hash_entry, h) {
2020 cand_id = (__u32)(long)hash_entry->value;
2021 cand = d->btf->types[cand_id];
2022 if (btf_equal_int(t, cand)) {
2023 new_id = cand_id;
2024 break;
2025 }
2026 }
2027 break;
2028
2029 case BTF_KIND_ENUM:
2030 h = btf_hash_enum(t);
2031 for_each_dedup_cand(d, hash_entry, h) {
2032 cand_id = (__u32)(long)hash_entry->value;
2033 cand = d->btf->types[cand_id];
2034 if (btf_equal_enum(t, cand)) {
2035 new_id = cand_id;
2036 break;
2037 }
2038 if (d->opts.dont_resolve_fwds)
2039 continue;
2040 if (btf_compat_enum(t, cand)) {
2041 if (btf_is_enum_fwd(t)) {
2042 /* resolve fwd to full enum */
2043 new_id = cand_id;
2044 break;
2045 }
2046 /* resolve canonical enum fwd to full enum */
2047 d->map[cand_id] = type_id;
2048 }
2049 }
2050 break;
2051
2052 case BTF_KIND_FWD:
2053 h = btf_hash_common(t);
2054 for_each_dedup_cand(d, hash_entry, h) {
2055 cand_id = (__u32)(long)hash_entry->value;
2056 cand = d->btf->types[cand_id];
2057 if (btf_equal_common(t, cand)) {
2058 new_id = cand_id;
2059 break;
2060 }
2061 }
2062 break;
2063
2064 default:
2065 return -EINVAL;
2066 }
2067
2068 d->map[type_id] = new_id;
2069 if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
2070 return -ENOMEM;
2071
2072 return 0;
2073}
2074
2075static int btf_dedup_prim_types(struct btf_dedup *d)
2076{
2077 int i, err;
2078
2079 for (i = 1; i <= d->btf->nr_types; i++) {
2080 err = btf_dedup_prim_type(d, i);
2081 if (err)
2082 return err;
2083 }
2084 return 0;
2085}
2086
2087/*
2088 * Check whether type is already mapped into canonical one (could be to itself).
2089 */
2090static inline bool is_type_mapped(struct btf_dedup *d, uint32_t type_id)
2091{
2092 return d->map[type_id] <= BTF_MAX_NR_TYPES;
2093}
2094
2095/*
2096 * Resolve type ID into its canonical type ID, if any; otherwise return original
2097 * type ID. If type is FWD and is resolved into STRUCT/UNION already, follow
2098 * STRUCT/UNION link and resolve it into canonical type ID as well.
2099 */
2100static inline __u32 resolve_type_id(struct btf_dedup *d, __u32 type_id)
2101{
2102 while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
2103 type_id = d->map[type_id];
2104 return type_id;
2105}
2106
2107/*
2108 * Resolve FWD to underlying STRUCT/UNION, if any; otherwise return original
2109 * type ID.
2110 */
2111static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
2112{
2113 __u32 orig_type_id = type_id;
2114
2115 if (!btf_is_fwd(d->btf->types[type_id]))
2116 return type_id;
2117
2118 while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
2119 type_id = d->map[type_id];
2120
2121 if (!btf_is_fwd(d->btf->types[type_id]))
2122 return type_id;
2123
2124 return orig_type_id;
2125}
2126
2127
2128static inline __u16 btf_fwd_kind(struct btf_type *t)
2129{
2130 return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT;
2131}
2132
2133/*
2134 * Check equivalence of BTF type graph formed by candidate struct/union (we'll
2135 * call it "candidate graph" in this description for brevity) to a type graph
2136 * formed by (potential) canonical struct/union ("canonical graph" for brevity
2137 * here, though keep in mind that not all types in canonical graph are
2138 * necessarily canonical representatives themselves, some of them might be
2139 * duplicates or its uniqueness might not have been established yet).
2140 * Returns:
2141 * - >0, if type graphs are equivalent;
2142 * - 0, if not equivalent;
2143 * - <0, on error.
2144 *
2145 * Algorithm performs side-by-side DFS traversal of both type graphs and checks
2146 * equivalence of BTF types at each step. If at any point BTF types in candidate
2147 * and canonical graphs are not compatible structurally, whole graphs are
2148 * incompatible. If types are structurally equivalent (i.e., all information
2149 * except referenced type IDs is exactly the same), a mapping from `canon_id` to
2150 * a `cand_id` is recored in hypothetical mapping (`btf_dedup->hypot_map`).
2151 * If a type references other types, then those referenced types are checked
2152 * for equivalence recursively.
2153 *
2154 * During DFS traversal, if we find that for current `canon_id` type we
2155 * already have some mapping in hypothetical map, we check for two possible
2156 * situations:
2157 * - `canon_id` is mapped to exactly the same type as `cand_id`. This will
2158 * happen when type graphs have cycles. In this case we assume those two
2159 * types are equivalent.
2160 * - `canon_id` is mapped to different type. This is contradiction in our
2161 * hypothetical mapping, because same graph in canonical graph corresponds
2162 * to two different types in candidate graph, which for equivalent type
2163 * graphs shouldn't happen. This condition terminates equivalence check
2164 * with negative result.
2165 *
2166 * If type graphs traversal exhausts types to check and find no contradiction,
2167 * then type graphs are equivalent.
2168 *
2169 * When checking types for equivalence, there is one special case: FWD types.
2170 * If FWD type resolution is allowed and one of the types (either from canonical
2171 * or candidate graph) is FWD and other is STRUCT/UNION (depending on FWD's kind
2172 * flag) and their names match, hypothetical mapping is updated to point from
2173 * FWD to STRUCT/UNION. If graphs will be determined as equivalent successfully,
2174 * this mapping will be used to record FWD -> STRUCT/UNION mapping permanently.
2175 *
2176 * Technically, this could lead to incorrect FWD to STRUCT/UNION resolution,
2177 * if there are two exactly named (or anonymous) structs/unions that are
2178 * compatible structurally, one of which has FWD field, while other is concrete
2179 * STRUCT/UNION, but according to C sources they are different structs/unions
2180 * that are referencing different types with the same name. This is extremely
2181 * unlikely to happen, but btf_dedup API allows to disable FWD resolution if
2182 * this logic is causing problems.
2183 *
2184 * Doing FWD resolution means that both candidate and/or canonical graphs can
2185 * consists of portions of the graph that come from multiple compilation units.
2186 * This is due to the fact that types within single compilation unit are always
2187 * deduplicated and FWDs are already resolved, if referenced struct/union
2188 * definiton is available. So, if we had unresolved FWD and found corresponding
2189 * STRUCT/UNION, they will be from different compilation units. This
2190 * consequently means that when we "link" FWD to corresponding STRUCT/UNION,
2191 * type graph will likely have at least two different BTF types that describe
2192 * same type (e.g., most probably there will be two different BTF types for the
2193 * same 'int' primitive type) and could even have "overlapping" parts of type
2194 * graph that describe same subset of types.
2195 *
2196 * This in turn means that our assumption that each type in canonical graph
2197 * must correspond to exactly one type in candidate graph might not hold
2198 * anymore and will make it harder to detect contradictions using hypothetical
2199 * map. To handle this problem, we allow to follow FWD -> STRUCT/UNION
2200 * resolution only in canonical graph. FWDs in candidate graphs are never
2201 * resolved. To see why it's OK, let's check all possible situations w.r.t. FWDs
2202 * that can occur:
2203 * - Both types in canonical and candidate graphs are FWDs. If they are
2204 * structurally equivalent, then they can either be both resolved to the
2205 * same STRUCT/UNION or not resolved at all. In both cases they are
2206 * equivalent and there is no need to resolve FWD on candidate side.
2207 * - Both types in canonical and candidate graphs are concrete STRUCT/UNION,
2208 * so nothing to resolve as well, algorithm will check equivalence anyway.
2209 * - Type in canonical graph is FWD, while type in candidate is concrete
2210 * STRUCT/UNION. In this case candidate graph comes from single compilation
2211 * unit, so there is exactly one BTF type for each unique C type. After
2212 * resolving FWD into STRUCT/UNION, there might be more than one BTF type
2213 * in canonical graph mapping to single BTF type in candidate graph, but
2214 * because hypothetical mapping maps from canonical to candidate types, it's
2215 * alright, and we still maintain the property of having single `canon_id`
2216 * mapping to single `cand_id` (there could be two different `canon_id`
2217 * mapped to the same `cand_id`, but it's not contradictory).
2218 * - Type in canonical graph is concrete STRUCT/UNION, while type in candidate
2219 * graph is FWD. In this case we are just going to check compatibility of
2220 * STRUCT/UNION and corresponding FWD, and if they are compatible, we'll
2221 * assume that whatever STRUCT/UNION FWD resolves to must be equivalent to
2222 * a concrete STRUCT/UNION from canonical graph. If the rest of type graphs
2223 * turn out equivalent, we'll re-resolve FWD to concrete STRUCT/UNION from
2224 * canonical graph.
2225 */
2226static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
2227 __u32 canon_id)
2228{
2229 struct btf_type *cand_type;
2230 struct btf_type *canon_type;
2231 __u32 hypot_type_id;
2232 __u16 cand_kind;
2233 __u16 canon_kind;
2234 int i, eq;
2235
2236 /* if both resolve to the same canonical, they must be equivalent */
2237 if (resolve_type_id(d, cand_id) == resolve_type_id(d, canon_id))
2238 return 1;
2239
2240 canon_id = resolve_fwd_id(d, canon_id);
2241
2242 hypot_type_id = d->hypot_map[canon_id];
2243 if (hypot_type_id <= BTF_MAX_NR_TYPES)
2244 return hypot_type_id == cand_id;
2245
2246 if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
2247 return -ENOMEM;
2248
2249 cand_type = d->btf->types[cand_id];
2250 canon_type = d->btf->types[canon_id];
2251 cand_kind = btf_kind(cand_type);
2252 canon_kind = btf_kind(canon_type);
2253
2254 if (cand_type->name_off != canon_type->name_off)
2255 return 0;
2256
2257 /* FWD <--> STRUCT/UNION equivalence check, if enabled */
2258 if (!d->opts.dont_resolve_fwds
2259 && (cand_kind == BTF_KIND_FWD || canon_kind == BTF_KIND_FWD)
2260 && cand_kind != canon_kind) {
2261 __u16 real_kind;
2262 __u16 fwd_kind;
2263
2264 if (cand_kind == BTF_KIND_FWD) {
2265 real_kind = canon_kind;
2266 fwd_kind = btf_fwd_kind(cand_type);
2267 } else {
2268 real_kind = cand_kind;
2269 fwd_kind = btf_fwd_kind(canon_type);
2270 }
2271 return fwd_kind == real_kind;
2272 }
2273
2274 if (cand_kind != canon_kind)
2275 return 0;
2276
2277 switch (cand_kind) {
2278 case BTF_KIND_INT:
2279 return btf_equal_int(cand_type, canon_type);
2280
2281 case BTF_KIND_ENUM:
2282 if (d->opts.dont_resolve_fwds)
2283 return btf_equal_enum(cand_type, canon_type);
2284 else
2285 return btf_compat_enum(cand_type, canon_type);
2286
2287 case BTF_KIND_FWD:
2288 return btf_equal_common(cand_type, canon_type);
2289
2290 case BTF_KIND_CONST:
2291 case BTF_KIND_VOLATILE:
2292 case BTF_KIND_RESTRICT:
2293 case BTF_KIND_PTR:
2294 case BTF_KIND_TYPEDEF:
2295 case BTF_KIND_FUNC:
2296 if (cand_type->info != canon_type->info)
2297 return 0;
2298 return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
2299
2300 case BTF_KIND_ARRAY: {
2301 const struct btf_array *cand_arr, *canon_arr;
2302
2303 if (!btf_compat_array(cand_type, canon_type))
2304 return 0;
2305 cand_arr = btf_array(cand_type);
2306 canon_arr = btf_array(canon_type);
2307 eq = btf_dedup_is_equiv(d,
2308 cand_arr->index_type, canon_arr->index_type);
2309 if (eq <= 0)
2310 return eq;
2311 return btf_dedup_is_equiv(d, cand_arr->type, canon_arr->type);
2312 }
2313
2314 case BTF_KIND_STRUCT:
2315 case BTF_KIND_UNION: {
2316 const struct btf_member *cand_m, *canon_m;
2317 __u16 vlen;
2318
2319 if (!btf_shallow_equal_struct(cand_type, canon_type))
2320 return 0;
2321 vlen = btf_vlen(cand_type);
2322 cand_m = btf_members(cand_type);
2323 canon_m = btf_members(canon_type);
2324 for (i = 0; i < vlen; i++) {
2325 eq = btf_dedup_is_equiv(d, cand_m->type, canon_m->type);
2326 if (eq <= 0)
2327 return eq;
2328 cand_m++;
2329 canon_m++;
2330 }
2331
2332 return 1;
2333 }
2334
2335 case BTF_KIND_FUNC_PROTO: {
2336 const struct btf_param *cand_p, *canon_p;
2337 __u16 vlen;
2338
2339 if (!btf_compat_fnproto(cand_type, canon_type))
2340 return 0;
2341 eq = btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
2342 if (eq <= 0)
2343 return eq;
2344 vlen = btf_vlen(cand_type);
2345 cand_p = btf_params(cand_type);
2346 canon_p = btf_params(canon_type);
2347 for (i = 0; i < vlen; i++) {
2348 eq = btf_dedup_is_equiv(d, cand_p->type, canon_p->type);
2349 if (eq <= 0)
2350 return eq;
2351 cand_p++;
2352 canon_p++;
2353 }
2354 return 1;
2355 }
2356
2357 default:
2358 return -EINVAL;
2359 }
2360 return 0;
2361}
2362
2363/*
2364 * Use hypothetical mapping, produced by successful type graph equivalence
2365 * check, to augment existing struct/union canonical mapping, where possible.
2366 *
2367 * If BTF_KIND_FWD resolution is allowed, this mapping is also used to record
2368 * FWD -> STRUCT/UNION correspondence as well. FWD resolution is bidirectional:
2369 * it doesn't matter if FWD type was part of canonical graph or candidate one,
2370 * we are recording the mapping anyway. As opposed to carefulness required
2371 * for struct/union correspondence mapping (described below), for FWD resolution
2372 * it's not important, as by the time that FWD type (reference type) will be
2373 * deduplicated all structs/unions will be deduped already anyway.
2374 *
2375 * Recording STRUCT/UNION mapping is purely a performance optimization and is
2376 * not required for correctness. It needs to be done carefully to ensure that
2377 * struct/union from candidate's type graph is not mapped into corresponding
2378 * struct/union from canonical type graph that itself hasn't been resolved into
2379 * canonical representative. The only guarantee we have is that canonical
2380 * struct/union was determined as canonical and that won't change. But any
2381 * types referenced through that struct/union fields could have been not yet
2382 * resolved, so in case like that it's too early to establish any kind of
2383 * correspondence between structs/unions.
2384 *
2385 * No canonical correspondence is derived for primitive types (they are already
2386 * deduplicated completely already anyway) or reference types (they rely on
2387 * stability of struct/union canonical relationship for equivalence checks).
2388 */
2389static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
2390{
2391 __u32 cand_type_id, targ_type_id;
2392 __u16 t_kind, c_kind;
2393 __u32 t_id, c_id;
2394 int i;
2395
2396 for (i = 0; i < d->hypot_cnt; i++) {
2397 cand_type_id = d->hypot_list[i];
2398 targ_type_id = d->hypot_map[cand_type_id];
2399 t_id = resolve_type_id(d, targ_type_id);
2400 c_id = resolve_type_id(d, cand_type_id);
2401 t_kind = btf_kind(d->btf->types[t_id]);
2402 c_kind = btf_kind(d->btf->types[c_id]);
2403 /*
2404 * Resolve FWD into STRUCT/UNION.
2405 * It's ok to resolve FWD into STRUCT/UNION that's not yet
2406 * mapped to canonical representative (as opposed to
2407 * STRUCT/UNION <--> STRUCT/UNION mapping logic below), because
2408 * eventually that struct is going to be mapped and all resolved
2409 * FWDs will automatically resolve to correct canonical
2410 * representative. This will happen before ref type deduping,
2411 * which critically depends on stability of these mapping. This
2412 * stability is not a requirement for STRUCT/UNION equivalence
2413 * checks, though.
2414 */
2415 if (t_kind != BTF_KIND_FWD && c_kind == BTF_KIND_FWD)
2416 d->map[c_id] = t_id;
2417 else if (t_kind == BTF_KIND_FWD && c_kind != BTF_KIND_FWD)
2418 d->map[t_id] = c_id;
2419
2420 if ((t_kind == BTF_KIND_STRUCT || t_kind == BTF_KIND_UNION) &&
2421 c_kind != BTF_KIND_FWD &&
2422 is_type_mapped(d, c_id) &&
2423 !is_type_mapped(d, t_id)) {
2424 /*
2425 * as a perf optimization, we can map struct/union
2426 * that's part of type graph we just verified for
2427 * equivalence. We can do that for struct/union that has
2428 * canonical representative only, though.
2429 */
2430 d->map[t_id] = c_id;
2431 }
2432 }
2433}
2434
2435/*
2436 * Deduplicate struct/union types.
2437 *
2438 * For each struct/union type its type signature hash is calculated, taking
2439 * into account type's name, size, number, order and names of fields, but
2440 * ignoring type ID's referenced from fields, because they might not be deduped
2441 * completely until after reference types deduplication phase. This type hash
2442 * is used to iterate over all potential canonical types, sharing same hash.
2443 * For each canonical candidate we check whether type graphs that they form
2444 * (through referenced types in fields and so on) are equivalent using algorithm
2445 * implemented in `btf_dedup_is_equiv`. If such equivalence is found and
2446 * BTF_KIND_FWD resolution is allowed, then hypothetical mapping
2447 * (btf_dedup->hypot_map) produced by aforementioned type graph equivalence
2448 * algorithm is used to record FWD -> STRUCT/UNION mapping. It's also used to
2449 * potentially map other structs/unions to their canonical representatives,
2450 * if such relationship hasn't yet been established. This speeds up algorithm
2451 * by eliminating some of the duplicate work.
2452 *
2453 * If no matching canonical representative was found, struct/union is marked
2454 * as canonical for itself and is added into btf_dedup->dedup_table hash map
2455 * for further look ups.
2456 */
2457static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
2458{
2459 struct btf_type *cand_type, *t;
2460 struct hashmap_entry *hash_entry;
2461 /* if we don't find equivalent type, then we are canonical */
2462 __u32 new_id = type_id;
2463 __u16 kind;
2464 long h;
2465
2466 /* already deduped or is in process of deduping (loop detected) */
2467 if (d->map[type_id] <= BTF_MAX_NR_TYPES)
2468 return 0;
2469
2470 t = d->btf->types[type_id];
2471 kind = btf_kind(t);
2472
2473 if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
2474 return 0;
2475
2476 h = btf_hash_struct(t);
2477 for_each_dedup_cand(d, hash_entry, h) {
2478 __u32 cand_id = (__u32)(long)hash_entry->value;
2479 int eq;
2480
2481 /*
2482 * Even though btf_dedup_is_equiv() checks for
2483 * btf_shallow_equal_struct() internally when checking two
2484 * structs (unions) for equivalence, we need to guard here
2485 * from picking matching FWD type as a dedup candidate.
2486 * This can happen due to hash collision. In such case just
2487 * relying on btf_dedup_is_equiv() would lead to potentially
2488 * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
2489 * FWD and compatible STRUCT/UNION are considered equivalent.
2490 */
2491 cand_type = d->btf->types[cand_id];
2492 if (!btf_shallow_equal_struct(t, cand_type))
2493 continue;
2494
2495 btf_dedup_clear_hypot_map(d);
2496 eq = btf_dedup_is_equiv(d, type_id, cand_id);
2497 if (eq < 0)
2498 return eq;
2499 if (!eq)
2500 continue;
2501 new_id = cand_id;
2502 btf_dedup_merge_hypot_map(d);
2503 break;
2504 }
2505
2506 d->map[type_id] = new_id;
2507 if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
2508 return -ENOMEM;
2509
2510 return 0;
2511}
2512
2513static int btf_dedup_struct_types(struct btf_dedup *d)
2514{
2515 int i, err;
2516
2517 for (i = 1; i <= d->btf->nr_types; i++) {
2518 err = btf_dedup_struct_type(d, i);
2519 if (err)
2520 return err;
2521 }
2522 return 0;
2523}
2524
2525/*
2526 * Deduplicate reference type.
2527 *
2528 * Once all primitive and struct/union types got deduplicated, we can easily
2529 * deduplicate all other (reference) BTF types. This is done in two steps:
2530 *
2531 * 1. Resolve all referenced type IDs into their canonical type IDs. This
2532 * resolution can be done either immediately for primitive or struct/union types
2533 * (because they were deduped in previous two phases) or recursively for
2534 * reference types. Recursion will always terminate at either primitive or
2535 * struct/union type, at which point we can "unwind" chain of reference types
2536 * one by one. There is no danger of encountering cycles because in C type
2537 * system the only way to form type cycle is through struct/union, so any chain
2538 * of reference types, even those taking part in a type cycle, will inevitably
2539 * reach struct/union at some point.
2540 *
2541 * 2. Once all referenced type IDs are resolved into canonical ones, BTF type
2542 * becomes "stable", in the sense that no further deduplication will cause
2543 * any changes to it. With that, it's now possible to calculate type's signature
2544 * hash (this time taking into account referenced type IDs) and loop over all
2545 * potential canonical representatives. If no match was found, current type
2546 * will become canonical representative of itself and will be added into
2547 * btf_dedup->dedup_table as another possible canonical representative.
2548 */
2549static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
2550{
2551 struct hashmap_entry *hash_entry;
2552 __u32 new_id = type_id, cand_id;
2553 struct btf_type *t, *cand;
2554 /* if we don't find equivalent type, then we are representative type */
2555 int ref_type_id;
2556 long h;
2557
2558 if (d->map[type_id] == BTF_IN_PROGRESS_ID)
2559 return -ELOOP;
2560 if (d->map[type_id] <= BTF_MAX_NR_TYPES)
2561 return resolve_type_id(d, type_id);
2562
2563 t = d->btf->types[type_id];
2564 d->map[type_id] = BTF_IN_PROGRESS_ID;
2565
2566 switch (btf_kind(t)) {
2567 case BTF_KIND_CONST:
2568 case BTF_KIND_VOLATILE:
2569 case BTF_KIND_RESTRICT:
2570 case BTF_KIND_PTR:
2571 case BTF_KIND_TYPEDEF:
2572 case BTF_KIND_FUNC:
2573 ref_type_id = btf_dedup_ref_type(d, t->type);
2574 if (ref_type_id < 0)
2575 return ref_type_id;
2576 t->type = ref_type_id;
2577
2578 h = btf_hash_common(t);
2579 for_each_dedup_cand(d, hash_entry, h) {
2580 cand_id = (__u32)(long)hash_entry->value;
2581 cand = d->btf->types[cand_id];
2582 if (btf_equal_common(t, cand)) {
2583 new_id = cand_id;
2584 break;
2585 }
2586 }
2587 break;
2588
2589 case BTF_KIND_ARRAY: {
2590 struct btf_array *info = btf_array(t);
2591
2592 ref_type_id = btf_dedup_ref_type(d, info->type);
2593 if (ref_type_id < 0)
2594 return ref_type_id;
2595 info->type = ref_type_id;
2596
2597 ref_type_id = btf_dedup_ref_type(d, info->index_type);
2598 if (ref_type_id < 0)
2599 return ref_type_id;
2600 info->index_type = ref_type_id;
2601
2602 h = btf_hash_array(t);
2603 for_each_dedup_cand(d, hash_entry, h) {
2604 cand_id = (__u32)(long)hash_entry->value;
2605 cand = d->btf->types[cand_id];
2606 if (btf_equal_array(t, cand)) {
2607 new_id = cand_id;
2608 break;
2609 }
2610 }
2611 break;
2612 }
2613
2614 case BTF_KIND_FUNC_PROTO: {
2615 struct btf_param *param;
2616 __u16 vlen;
2617 int i;
2618
2619 ref_type_id = btf_dedup_ref_type(d, t->type);
2620 if (ref_type_id < 0)
2621 return ref_type_id;
2622 t->type = ref_type_id;
2623
2624 vlen = btf_vlen(t);
2625 param = btf_params(t);
2626 for (i = 0; i < vlen; i++) {
2627 ref_type_id = btf_dedup_ref_type(d, param->type);
2628 if (ref_type_id < 0)
2629 return ref_type_id;
2630 param->type = ref_type_id;
2631 param++;
2632 }
2633
2634 h = btf_hash_fnproto(t);
2635 for_each_dedup_cand(d, hash_entry, h) {
2636 cand_id = (__u32)(long)hash_entry->value;
2637 cand = d->btf->types[cand_id];
2638 if (btf_equal_fnproto(t, cand)) {
2639 new_id = cand_id;
2640 break;
2641 }
2642 }
2643 break;
2644 }
2645
2646 default:
2647 return -EINVAL;
2648 }
2649
2650 d->map[type_id] = new_id;
2651 if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
2652 return -ENOMEM;
2653
2654 return new_id;
2655}
2656
2657static int btf_dedup_ref_types(struct btf_dedup *d)
2658{
2659 int i, err;
2660
2661 for (i = 1; i <= d->btf->nr_types; i++) {
2662 err = btf_dedup_ref_type(d, i);
2663 if (err < 0)
2664 return err;
2665 }
2666 /* we won't need d->dedup_table anymore */
2667 hashmap__free(d->dedup_table);
2668 d->dedup_table = NULL;
2669 return 0;
2670}
2671
2672/*
2673 * Compact types.
2674 *
2675 * After we established for each type its corresponding canonical representative
2676 * type, we now can eliminate types that are not canonical and leave only
2677 * canonical ones layed out sequentially in memory by copying them over
2678 * duplicates. During compaction btf_dedup->hypot_map array is reused to store
2679 * a map from original type ID to a new compacted type ID, which will be used
2680 * during next phase to "fix up" type IDs, referenced from struct/union and
2681 * reference types.
2682 */
2683static int btf_dedup_compact_types(struct btf_dedup *d)
2684{
2685 struct btf_type **new_types;
2686 __u32 next_type_id = 1;
2687 char *types_start, *p;
2688 int i, len;
2689
2690 /* we are going to reuse hypot_map to store compaction remapping */
2691 d->hypot_map[0] = 0;
2692 for (i = 1; i <= d->btf->nr_types; i++)
2693 d->hypot_map[i] = BTF_UNPROCESSED_ID;
2694
2695 types_start = d->btf->nohdr_data + d->btf->hdr->type_off;
2696 p = types_start;
2697
2698 for (i = 1; i <= d->btf->nr_types; i++) {
2699 if (d->map[i] != i)
2700 continue;
2701
2702 len = btf_type_size(d->btf->types[i]);
2703 if (len < 0)
2704 return len;
2705
2706 memmove(p, d->btf->types[i], len);
2707 d->hypot_map[i] = next_type_id;
2708 d->btf->types[next_type_id] = (struct btf_type *)p;
2709 p += len;
2710 next_type_id++;
2711 }
2712
2713 /* shrink struct btf's internal types index and update btf_header */
2714 d->btf->nr_types = next_type_id - 1;
2715 d->btf->types_size = d->btf->nr_types;
2716 d->btf->hdr->type_len = p - types_start;
2717 new_types = realloc(d->btf->types,
2718 (1 + d->btf->nr_types) * sizeof(struct btf_type *));
2719 if (!new_types)
2720 return -ENOMEM;
2721 d->btf->types = new_types;
2722
2723 /* make sure string section follows type information without gaps */
2724 d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data;
2725 memmove(p, d->btf->strings, d->btf->hdr->str_len);
2726 d->btf->strings = p;
2727 p += d->btf->hdr->str_len;
2728
2729 d->btf->data_size = p - (char *)d->btf->data;
2730 return 0;
2731}
2732
2733/*
2734 * Figure out final (deduplicated and compacted) type ID for provided original
2735 * `type_id` by first resolving it into corresponding canonical type ID and
2736 * then mapping it to a deduplicated type ID, stored in btf_dedup->hypot_map,
2737 * which is populated during compaction phase.
2738 */
2739static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id)
2740{
2741 __u32 resolved_type_id, new_type_id;
2742
2743 resolved_type_id = resolve_type_id(d, type_id);
2744 new_type_id = d->hypot_map[resolved_type_id];
2745 if (new_type_id > BTF_MAX_NR_TYPES)
2746 return -EINVAL;
2747 return new_type_id;
2748}
2749
2750/*
2751 * Remap referenced type IDs into deduped type IDs.
2752 *
2753 * After BTF types are deduplicated and compacted, their final type IDs may
2754 * differ from original ones. The map from original to a corresponding
2755 * deduped type ID is stored in btf_dedup->hypot_map and is populated during
2756 * compaction phase. During remapping phase we are rewriting all type IDs
2757 * referenced from any BTF type (e.g., struct fields, func proto args, etc) to
2758 * their final deduped type IDs.
2759 */
2760static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id)
2761{
2762 struct btf_type *t = d->btf->types[type_id];
2763 int i, r;
2764
2765 switch (btf_kind(t)) {
2766 case BTF_KIND_INT:
2767 case BTF_KIND_ENUM:
2768 break;
2769
2770 case BTF_KIND_FWD:
2771 case BTF_KIND_CONST:
2772 case BTF_KIND_VOLATILE:
2773 case BTF_KIND_RESTRICT:
2774 case BTF_KIND_PTR:
2775 case BTF_KIND_TYPEDEF:
2776 case BTF_KIND_FUNC:
2777 case BTF_KIND_VAR:
2778 r = btf_dedup_remap_type_id(d, t->type);
2779 if (r < 0)
2780 return r;
2781 t->type = r;
2782 break;
2783
2784 case BTF_KIND_ARRAY: {
2785 struct btf_array *arr_info = btf_array(t);
2786
2787 r = btf_dedup_remap_type_id(d, arr_info->type);
2788 if (r < 0)
2789 return r;
2790 arr_info->type = r;
2791 r = btf_dedup_remap_type_id(d, arr_info->index_type);
2792 if (r < 0)
2793 return r;
2794 arr_info->index_type = r;
2795 break;
2796 }
2797
2798 case BTF_KIND_STRUCT:
2799 case BTF_KIND_UNION: {
2800 struct btf_member *member = btf_members(t);
2801 __u16 vlen = btf_vlen(t);
2802
2803 for (i = 0; i < vlen; i++) {
2804 r = btf_dedup_remap_type_id(d, member->type);
2805 if (r < 0)
2806 return r;
2807 member->type = r;
2808 member++;
2809 }
2810 break;
2811 }
2812
2813 case BTF_KIND_FUNC_PROTO: {
2814 struct btf_param *param = btf_params(t);
2815 __u16 vlen = btf_vlen(t);
2816
2817 r = btf_dedup_remap_type_id(d, t->type);
2818 if (r < 0)
2819 return r;
2820 t->type = r;
2821
2822 for (i = 0; i < vlen; i++) {
2823 r = btf_dedup_remap_type_id(d, param->type);
2824 if (r < 0)
2825 return r;
2826 param->type = r;
2827 param++;
2828 }
2829 break;
2830 }
2831
2832 case BTF_KIND_DATASEC: {
2833 struct btf_var_secinfo *var = btf_var_secinfos(t);
2834 __u16 vlen = btf_vlen(t);
2835
2836 for (i = 0; i < vlen; i++) {
2837 r = btf_dedup_remap_type_id(d, var->type);
2838 if (r < 0)
2839 return r;
2840 var->type = r;
2841 var++;
2842 }
2843 break;
2844 }
2845
2846 default:
2847 return -EINVAL;
2848 }
2849
2850 return 0;
2851}
2852
2853static int btf_dedup_remap_types(struct btf_dedup *d)
2854{
2855 int i, r;
2856
2857 for (i = 1; i <= d->btf->nr_types; i++) {
2858 r = btf_dedup_remap_type(d, i);
2859 if (r < 0)
2860 return r;
2861 }
2862 return 0;
2863}