forked from acmel/dwarves
-
Notifications
You must be signed in to change notification settings - Fork 0
/
btf_encoder.c
1415 lines (1196 loc) · 38.5 KB
/
btf_encoder.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
SPDX-License-Identifier: GPL-2.0-only
Copyright (C) 2019 Facebook
Derived from ctf_encoder.c, which is:
Copyright (C) Arnaldo Carvalho de Melo <[email protected]>
Copyright (C) Red Hat Inc
*/
#include "dwarves.h"
#include "elf_symtab.h"
#include "btf_encoder.h"
#include <linux/btf.h>
#include <bpf/libbpf.h>
#include <ctype.h> /* for isalpha() and isalnum() */
#include <stdlib.h> /* for qsort() and bsearch() */
#include <inttypes.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#define PERCPU_SECTION ".data..percpu"
/*
* This depends on the GNU extension to eliminate the stray comma in the zero
* arguments case.
*
* The difference between elf_errmsg(-1) and elf_errmsg(elf_errno()) is that the
* latter clears the current error.
*/
#define elf_error(fmt, ...) \
fprintf(stderr, "%s: " fmt ": %s.\n", __func__, ##__VA_ARGS__, elf_errmsg(-1))
/*
* This depends on the GNU extension to eliminate the stray comma in the zero
* arguments case.
*
* The difference between elf_errmsg(-1) and elf_errmsg(elf_errno()) is that the
* latter clears the current error.
*/
#define elf_error(fmt, ...) \
fprintf(stderr, "%s: " fmt ": %s.\n", __func__, ##__VA_ARGS__, elf_errmsg(-1))
static int btf_var_secinfo_cmp(const void *a, const void *b)
{
const struct btf_var_secinfo *av = a;
const struct btf_var_secinfo *bv = b;
return av->offset - bv->offset;
}
#define BITS_PER_BYTE 8
#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
static const char * const btf_kind_str[NR_BTF_KINDS] = {
[BTF_KIND_UNKN] = "UNKNOWN",
[BTF_KIND_INT] = "INT",
[BTF_KIND_PTR] = "PTR",
[BTF_KIND_ARRAY] = "ARRAY",
[BTF_KIND_STRUCT] = "STRUCT",
[BTF_KIND_UNION] = "UNION",
[BTF_KIND_ENUM] = "ENUM",
[BTF_KIND_FWD] = "FWD",
[BTF_KIND_TYPEDEF] = "TYPEDEF",
[BTF_KIND_VOLATILE] = "VOLATILE",
[BTF_KIND_CONST] = "CONST",
[BTF_KIND_RESTRICT] = "RESTRICT",
[BTF_KIND_FUNC] = "FUNC",
[BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
[BTF_KIND_VAR] = "VAR",
[BTF_KIND_DATASEC] = "DATASEC",
[BTF_KIND_FLOAT] = "FLOAT",
};
static const char *btf__printable_name(const struct btf *btf, uint32_t offset)
{
if (!offset)
return "(anon)";
else
return btf__str_by_offset(btf, offset);
}
static const char * btf__int_encoding_str(uint8_t encoding)
{
if (encoding == 0)
return "(none)";
else if (encoding == BTF_INT_SIGNED)
return "SIGNED";
else if (encoding == BTF_INT_CHAR)
return "CHAR";
else if (encoding == BTF_INT_BOOL)
return "BOOL";
else
return "UNKN";
}
__attribute ((format (printf, 5, 6)))
static void btf__log_err(const struct btf *btf, int kind, const char *name,
bool output_cr, const char *fmt, ...)
{
fprintf(stderr, "[%u] %s %s", btf__get_nr_types(btf) + 1,
btf_kind_str[kind], name ?: "(anon)");
if (fmt && *fmt) {
va_list ap;
fprintf(stderr, " ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
if (output_cr)
fprintf(stderr, "\n");
}
__attribute ((format (printf, 5, 6)))
static void btf_encoder__log_type(const struct btf_encoder *encoder, const struct btf_type *t,
bool err, bool output_cr, const char *fmt, ...)
{
const struct btf *btf = encoder->btf;
uint8_t kind;
FILE *out;
if (!encoder->verbose && !err)
return;
kind = BTF_INFO_KIND(t->info);
out = err ? stderr : stdout;
fprintf(out, "[%u] %s %s",
btf__get_nr_types(btf), btf_kind_str[kind],
btf__printable_name(btf, t->name_off));
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
if (output_cr)
fprintf(out, "\n");
}
__attribute ((format (printf, 5, 6)))
static void btf_encoder__log_member(const struct btf_encoder *encoder, const struct btf_type *t,
const struct btf_member *member, bool err, const char *fmt, ...)
{
const struct btf *btf = encoder->btf;
FILE *out;
if (!encoder->verbose && !err)
return;
out = err ? stderr : stdout;
if (btf_kflag(t))
fprintf(out, "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
btf__printable_name(btf, member->name_off),
member->type,
BTF_MEMBER_BITFIELD_SIZE(member->offset),
BTF_MEMBER_BIT_OFFSET(member->offset));
else
fprintf(out, "\t%s type_id=%u bits_offset=%u",
btf__printable_name(btf, member->name_off),
member->type,
member->offset);
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
fprintf(out, "\n");
}
__attribute ((format (printf, 6, 7)))
static void btf_encoder__log_func_param(struct btf_encoder *encoder, const char *name, uint32_t type,
bool err, bool is_last_param, const char *fmt, ...)
{
FILE *out;
if (!encoder->verbose && !err)
return;
out = err ? stderr : stdout;
if (is_last_param && !type)
fprintf(out, "vararg)\n");
else
fprintf(out, "%u %s%s", type, name, is_last_param ? ")\n" : ", ");
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
}
static int32_t btf_encoder__add_float(struct btf_encoder *encoder, const struct base_type *bt, const char *name)
{
int32_t id = btf__add_float(encoder->btf, name, BITS_ROUNDUP_BYTES(bt->bit_size));
if (id < 0) {
btf__log_err(encoder->btf, BTF_KIND_FLOAT, name, true, "Error emitting BTF type");
} else {
const struct btf_type *t;
t = btf__type_by_id(encoder->btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u nr_bits=%u", t->size, bt->bit_size);
}
return id;
}
static int32_t btf_encoder__add_base_type(struct btf_encoder *encoder, const struct base_type *bt, const char *name)
{
const struct btf_type *t;
uint8_t encoding = 0;
uint16_t byte_sz;
int32_t id;
if (bt->is_signed) {
encoding = BTF_INT_SIGNED;
} else if (bt->is_bool) {
encoding = BTF_INT_BOOL;
} else if (bt->float_type && encoder->gen_floats) {
/*
* Encode floats as BTF_KIND_FLOAT if allowed, otherwise (in
* compatibility mode) encode them as BTF_KIND_INT - that's not
* fully correct, but that's what it used to be.
*/
if (bt->float_type == BT_FP_SINGLE ||
bt->float_type == BT_FP_DOUBLE ||
bt->float_type == BT_FP_LDBL)
return btf_encoder__add_float(encoder, bt, name);
fprintf(stderr, "Complex, interval and imaginary float types are not supported\n");
return -1;
}
/* dwarf5 may emit DW_ATE_[un]signed_{num} base types where
* {num} is not power of 2 and may exceed 128. Such attributes
* are mostly used to record operation for an actual parameter
* or variable.
* For example,
* DW_AT_location (indexed (0x3c) loclist = 0x00008fb0:
* [0xffffffff82808812, 0xffffffff82808817):
* DW_OP_breg0 RAX+0,
* DW_OP_convert (0x000e97d5) "DW_ATE_unsigned_64",
* DW_OP_convert (0x000e97df) "DW_ATE_unsigned_8",
* DW_OP_stack_value,
* DW_OP_piece 0x1,
* DW_OP_breg0 RAX+0,
* DW_OP_convert (0x000e97d5) "DW_ATE_unsigned_64",
* DW_OP_convert (0x000e97da) "DW_ATE_unsigned_32",
* DW_OP_lit8,
* DW_OP_shr,
* DW_OP_convert (0x000e97da) "DW_ATE_unsigned_32",
* DW_OP_convert (0x000e97e4) "DW_ATE_unsigned_24",
* DW_OP_stack_value, DW_OP_piece 0x3
* DW_AT_name ("ebx")
* DW_AT_decl_file ("/linux/arch/x86/events/intel/core.c")
*
* In the above example, at some point, one unsigned_32 value
* is right shifted by 8 and the result is converted to unsigned_32
* and then unsigned_24.
*
* BTF does not need such DW_OP_* information so let us sanitize
* these non-regular int types to avoid libbpf/kernel complaints.
*/
byte_sz = BITS_ROUNDUP_BYTES(bt->bit_size);
if (!byte_sz || (byte_sz & (byte_sz - 1))) {
name = "__SANITIZED_FAKE_INT__";
byte_sz = 4;
}
id = btf__add_int(encoder->btf, name, byte_sz, encoding);
if (id < 0) {
btf__log_err(encoder->btf, BTF_KIND_INT, name, true, "Error emitting BTF type");
} else {
t = btf__type_by_id(encoder->btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u nr_bits=%u encoding=%s%s",
t->size, bt->bit_size, btf__int_encoding_str(encoding),
id < 0 ? " Error in emitting BTF" : "" );
}
return id;
}
static int32_t btf_encoder__add_ref_type(struct btf_encoder *encoder, uint16_t kind, uint32_t type,
const char *name, bool kind_flag)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
switch (kind) {
case BTF_KIND_PTR:
id = btf__add_ptr(btf, type);
break;
case BTF_KIND_VOLATILE:
id = btf__add_volatile(btf, type);
break;
case BTF_KIND_CONST:
id = btf__add_const(btf, type);
break;
case BTF_KIND_RESTRICT:
id = btf__add_restrict(btf, type);
break;
case BTF_KIND_TYPEDEF:
id = btf__add_typedef(btf, name, type);
break;
case BTF_KIND_FWD:
id = btf__add_fwd(btf, name, kind_flag);
break;
case BTF_KIND_FUNC:
id = btf__add_func(btf, name, BTF_FUNC_STATIC, type);
break;
default:
btf__log_err(btf, kind, name, true, "Unexpected kind for reference");
return -1;
}
if (id > 0) {
t = btf__type_by_id(btf, id);
if (kind == BTF_KIND_FWD)
btf_encoder__log_type(encoder, t, false, true, "%s", kind_flag ? "union" : "struct");
else
btf_encoder__log_type(encoder, t, false, true, "type_id=%u", t->type);
} else {
btf__log_err(btf, kind, name, true, "Error emitting BTF type");
}
return id;
}
static int32_t btf_encoder__add_array(struct btf_encoder *encoder, uint32_t type, uint32_t index_type, uint32_t nelems)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
const struct btf_array *array;
int32_t id;
id = btf__add_array(btf, index_type, type, nelems);
if (id > 0) {
t = btf__type_by_id(btf, id);
array = btf_array(t);
btf_encoder__log_type(encoder, t, false, true, "type_id=%u index_type_id=%u nr_elems=%u",
array->type, array->index_type, array->nelems);
} else {
btf__log_err(btf, BTF_KIND_ARRAY, NULL, true,
"type_id=%u index_type_id=%u nr_elems=%u Error emitting BTF type",
type, index_type, nelems);
}
return id;
}
static int btf_encoder__add_field(struct btf_encoder *encoder, const char *name, uint32_t type, uint32_t bitfield_size, uint32_t offset)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
const struct btf_member *m;
int err;
err = btf__add_field(btf, name, type, offset, bitfield_size);
t = btf__type_by_id(btf, btf__get_nr_types(btf));
if (err) {
fprintf(stderr, "[%u] %s %s's field '%s' offset=%u bit_size=%u type=%u Error emitting field\n",
btf__get_nr_types(btf), btf_kind_str[btf_kind(t)],
btf__printable_name(btf, t->name_off),
name, offset, bitfield_size, type);
} else {
m = &btf_members(t)[btf_vlen(t) - 1];
btf_encoder__log_member(encoder, t, m, false, NULL);
}
return err;
}
static int32_t btf_encoder__add_struct(struct btf_encoder *encoder, uint8_t kind, const char *name, uint32_t size)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
switch (kind) {
case BTF_KIND_STRUCT:
id = btf__add_struct(btf, name, size);
break;
case BTF_KIND_UNION:
id = btf__add_union(btf, name, size);
break;
default:
btf__log_err(btf, kind, name, true, "Unexpected kind of struct");
return -1;
}
if (id < 0) {
btf__log_err(btf, kind, name, true, "Error emitting BTF type");
} else {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u", t->size);
}
return id;
}
static int32_t btf_encoder__add_enum(struct btf_encoder *encoder, const char *name, uint32_t bit_size)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id, size;
size = BITS_ROUNDUP_BYTES(bit_size);
id = btf__add_enum(btf, name, size);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u", t->size);
} else {
btf__log_err(btf, BTF_KIND_ENUM, name, true,
"size=%u Error emitting BTF type", size);
}
return id;
}
static int btf_encoder__add_enum_val(struct btf_encoder *encoder, const char *name, int32_t value)
{
int err = btf__add_enum_value(encoder->btf, name, value);
if (!err) {
if (encoder->verbose)
printf("\t%s val=%d\n", name, value);
} else {
fprintf(stderr, "\t%s val=%d Error emitting BTF enum value\n",
name, value);
}
return err;
}
static int32_t btf_encoder__add_func_param(struct btf_encoder *encoder, const char *name, uint32_t type, bool is_last_param)
{
int err = btf__add_func_param(encoder->btf, name, type);
if (!err) {
btf_encoder__log_func_param(encoder, name, type, false, is_last_param, NULL);
return 0;
} else {
btf_encoder__log_func_param(encoder, name, type, true, is_last_param, "Error adding func param");
return -1;
}
}
extern struct debug_fmt_ops *dwarves__active_loader;
static int32_t btf_encoder__add_func_proto(struct btf_encoder *encoder, struct cu *cu, struct ftype *ftype, uint32_t type_id_off)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
struct parameter *param;
uint16_t nr_params, param_idx;
int32_t id, type_id;
/* add btf_type for func_proto */
nr_params = ftype->nr_parms + (ftype->unspec_parms ? 1 : 0);
type_id = ftype->tag.type == 0 ? 0 : type_id_off + ftype->tag.type;
id = btf__add_func_proto(btf, type_id);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, false, "return=%u args=(%s", t->type, !nr_params ? "void)\n" : "");
} else {
btf__log_err(btf, BTF_KIND_FUNC_PROTO, NULL, true,
"return=%u vlen=%u Error emitting BTF type",
type_id, nr_params);
return id;
}
/* add parameters */
param_idx = 0;
ftype__for_each_parameter(ftype, param) {
const char *name = dwarves__active_loader->strings__ptr(cu, param->name);
type_id = param->tag.type == 0 ? 0 : type_id_off + param->tag.type;
++param_idx;
if (btf_encoder__add_func_param(encoder, name, type_id, param_idx == nr_params))
return -1;
}
++param_idx;
if (ftype->unspec_parms)
if (btf_encoder__add_func_param(encoder, NULL, 0, param_idx == nr_params))
return -1;
return id;
}
static int32_t btf_encoder__add_var(struct btf_encoder *encoder, uint32_t type, const char *name, uint32_t linkage)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
id = btf__add_var(btf, name, linkage, type);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "type=%u linkage=%u", t->type, btf_var(t)->linkage);
} else {
btf__log_err(btf, BTF_KIND_VAR, name, true,
"type=%u linkage=%u Error emitting BTF type",
type, linkage);
}
return id;
}
static int32_t btf_encoder__add_var_secinfo(struct btf_encoder *encoder, uint32_t type,
uint32_t offset, uint32_t size)
{
struct btf_var_secinfo si = {
.type = type,
.offset = offset,
.size = size,
};
return gobuffer__add(&encoder->percpu_secinfo, &si, sizeof(si));
}
static int32_t btf_encoder__add_datasec(struct btf_encoder *encoder, const char *section_name)
{
struct gobuffer *var_secinfo_buf = &encoder->percpu_secinfo;
struct btf *btf = encoder->btf;
size_t sz = gobuffer__size(var_secinfo_buf);
uint16_t nr_var_secinfo = sz / sizeof(struct btf_var_secinfo);
struct btf_var_secinfo *last_vsi, *vsi;
const struct btf_type *t;
uint32_t datasec_sz;
int32_t err, id, i;
qsort(var_secinfo_buf->entries, nr_var_secinfo,
sizeof(struct btf_var_secinfo), btf_var_secinfo_cmp);
last_vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + nr_var_secinfo - 1;
datasec_sz = last_vsi->offset + last_vsi->size;
id = btf__add_datasec(btf, section_name, datasec_sz);
if (id < 0) {
btf__log_err(btf, BTF_KIND_DATASEC, section_name, true,
"size=%u vlen=%u Error emitting BTF type",
datasec_sz, nr_var_secinfo);
} else {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u vlen=%u", t->size, nr_var_secinfo);
}
for (i = 0; i < nr_var_secinfo; i++) {
vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + i;
err = btf__add_datasec_var_info(btf, vsi->type, vsi->offset, vsi->size);
if (!err) {
if (encoder->verbose)
printf("\ttype=%u offset=%u size=%u\n",
vsi->type, vsi->offset, vsi->size);
} else {
fprintf(stderr, "\ttype=%u offset=%u size=%u Error emitting BTF datasec var info\n",
vsi->type, vsi->offset, vsi->size);
return -1;
}
}
return id;
}
/*
* This corresponds to the same macro defined in
* include/linux/kallsyms.h
*/
#define KSYM_NAME_LEN 128
struct elf_function {
const char *name;
bool generated;
};
static int functions_cmp(const void *_a, const void *_b)
{
const struct elf_function *a = _a;
const struct elf_function *b = _b;
return strcmp(a->name, b->name);
}
#ifndef max
#define max(x, y) ((x) < (y) ? (y) : (x))
#endif
static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *sym)
{
struct elf_function *new;
const char *name;
if (elf_sym__type(sym) != STT_FUNC)
return 0;
name = elf_sym__name(sym, encoder->symtab);
if (!name)
return 0;
if (encoder->functions.cnt == encoder->functions.allocated) {
encoder->functions.allocated = max(1000, encoder->functions.allocated * 3 / 2);
new = realloc(encoder->functions.entries, encoder->functions.allocated * sizeof(*encoder->functions.entries));
if (!new) {
/*
* The cleanup - delete_functions is called
* in btf_encoder__encode_cu error path.
*/
return -1;
}
encoder->functions.entries = new;
}
encoder->functions.entries[encoder->functions.cnt].name = name;
encoder->functions.entries[encoder->functions.cnt].generated = false;
encoder->functions.cnt++;
return 0;
}
static struct elf_function *btf_encoder__find_function(const struct btf_encoder *encoder, const char *name)
{
struct elf_function key = { .name = name };
return bsearch(&key, encoder->functions.entries, encoder->functions.cnt, sizeof(key), functions_cmp);
}
static bool btf_name_char_ok(char c, bool first)
{
if (c == '_' || c == '.')
return true;
return first ? isalpha(c) : isalnum(c);
}
/* Check whether the given name is valid in vmlinux btf. */
static bool btf_name_valid(const char *p)
{
const char *limit;
if (!btf_name_char_ok(*p, true))
return false;
/* set a limit on identifier length */
limit = p + KSYM_NAME_LEN;
p++;
while (*p && p < limit) {
if (!btf_name_char_ok(*p, false))
return false;
p++;
}
return !*p;
}
static void dump_invalid_symbol(const char *msg, const char *sym,
int verbose, bool force)
{
if (force) {
if (verbose)
fprintf(stderr, "PAHOLE: Warning: %s, ignored (sym: '%s').\n",
msg, sym);
return;
}
fprintf(stderr, "PAHOLE: Error: %s (sym: '%s').\n", msg, sym);
fprintf(stderr, "PAHOLE: Error: Use '--btf_encode_force' to ignore such symbols and force emit the btf.\n");
}
extern struct debug_fmt_ops *dwarves__active_loader;
static int tag__check_id_drift(const struct tag *tag,
uint32_t core_id, uint32_t btf_type_id,
uint32_t type_id_off)
{
if (btf_type_id != (core_id + type_id_off)) {
fprintf(stderr,
"%s: %s id drift, core_id: %u, btf_type_id: %u, type_id_off: %u\n",
__func__, dwarf_tag_name(tag->tag),
core_id, btf_type_id, type_id_off);
return -1;
}
return 0;
}
static int32_t btf_encoder__add_struct_type(struct btf_encoder *encoder, struct cu *cu, struct tag *tag, uint32_t type_id_off)
{
struct type *type = tag__type(tag);
struct class_member *pos;
const char *name;
int32_t type_id;
uint8_t kind;
kind = (tag->tag == DW_TAG_union_type) ?
BTF_KIND_UNION : BTF_KIND_STRUCT;
name = dwarves__active_loader->strings__ptr(cu, type->namespace.name);
type_id = btf_encoder__add_struct(encoder, kind, name, type->size);
if (type_id < 0)
return type_id;
type__for_each_data_member(type, pos) {
/*
* dwarf_loader uses DWARF's recommended bit offset addressing
* scheme, which conforms to BTF requirement, so no conversion
* is required.
*/
name = dwarves__active_loader->strings__ptr(cu, pos->name);
if (btf_encoder__add_field(encoder, name, type_id_off + pos->tag.type, pos->bitfield_size, pos->bit_offset))
return -1;
}
return type_id;
}
static uint32_t array_type__nelems(struct tag *tag)
{
int i;
uint32_t nelem = 1;
struct array_type *array = tag__array_type(tag);
for (i = array->dimensions - 1; i >= 0; --i)
nelem *= array->nr_entries[i];
return nelem;
}
static int32_t btf_encoder__add_enum_type(struct btf_encoder *encoder, struct cu *cu, struct tag *tag)
{
struct type *etype = tag__type(tag);
struct enumerator *pos;
const char *name;
int32_t type_id;
name = dwarves__active_loader->strings__ptr(cu, etype->namespace.name);
type_id = btf_encoder__add_enum(encoder, name, etype->size);
if (type_id < 0)
return type_id;
type__for_each_enumerator(etype, pos) {
name = dwarves__active_loader->strings__ptr(cu, pos->name);
if (btf_encoder__add_enum_val(encoder, name, pos->value))
return -1;
}
return type_id;
}
static int btf_encoder__encode_tag(struct btf_encoder *encoder, struct cu *cu, struct tag *tag,
uint32_t core_id, uint32_t type_id_off)
{
/* single out type 0 as it represents special type "void" */
uint32_t ref_type_id = tag->type == 0 ? 0 : type_id_off + tag->type;
const char *name;
switch (tag->tag) {
case DW_TAG_base_type:
name = dwarves__active_loader->strings__ptr(cu, tag__base_type(tag)->name);
return btf_encoder__add_base_type(encoder, tag__base_type(tag), name);
case DW_TAG_const_type:
return btf_encoder__add_ref_type(encoder, BTF_KIND_CONST, ref_type_id, NULL, false);
case DW_TAG_pointer_type:
return btf_encoder__add_ref_type(encoder, BTF_KIND_PTR, ref_type_id, NULL, false);
case DW_TAG_restrict_type:
return btf_encoder__add_ref_type(encoder, BTF_KIND_RESTRICT, ref_type_id, NULL, false);
case DW_TAG_volatile_type:
return btf_encoder__add_ref_type(encoder, BTF_KIND_VOLATILE, ref_type_id, NULL, false);
case DW_TAG_typedef:
name = dwarves__active_loader->strings__ptr(cu, tag__namespace(tag)->name);
return btf_encoder__add_ref_type(encoder, BTF_KIND_TYPEDEF, ref_type_id, name, false);
case DW_TAG_structure_type:
case DW_TAG_union_type:
case DW_TAG_class_type:
name = dwarves__active_loader->strings__ptr(cu, tag__namespace(tag)->name);
if (tag__type(tag)->declaration)
return btf_encoder__add_ref_type(encoder, BTF_KIND_FWD, 0, name, tag->tag == DW_TAG_union_type);
else
return btf_encoder__add_struct_type(encoder, cu, tag, type_id_off);
case DW_TAG_array_type:
/* TODO: Encode one dimension at a time. */
encoder->need_index_type = true;
return btf_encoder__add_array(encoder, ref_type_id, encoder->array_index_id, array_type__nelems(tag));
case DW_TAG_enumeration_type:
return btf_encoder__add_enum_type(encoder, cu, tag);
case DW_TAG_subroutine_type:
return btf_encoder__add_func_proto(encoder, cu, tag__ftype(tag), type_id_off);
default:
fprintf(stderr, "Unsupported DW_TAG_%s(0x%x)\n",
dwarf_tag_name(tag->tag), tag->tag);
return -1;
}
}
static int btf__encode_as_raw_file(struct btf *btf, const char *filename)
{
uint32_t raw_btf_size;
const void *raw_btf_data;
int fd, err;
/* Empty file, nothing to do, so... done! */
if (btf__get_nr_types(btf) == 0)
return 0;
if (btf__dedup(btf, NULL, NULL)) {
fprintf(stderr, "%s: btf__dedup failed!\n", __func__);
return -1;
}
raw_btf_data = btf__get_raw_data(btf, &raw_btf_size);
if (raw_btf_data == NULL) {
fprintf(stderr, "%s: btf__get_raw_data failed!\n", __func__);
return -1;
}
fd = open(filename, O_WRONLY | O_CREAT, 0640);
if (fd < 0) {
fprintf(stderr, "%s: Couldn't open %s for writing the raw BTF info: %s\n", __func__, filename, strerror(errno));
return -1;
}
err = write(fd, raw_btf_data, raw_btf_size);
if (err < 0)
fprintf(stderr, "%s: Couldn't write the raw BTF info to %s: %s\n", __func__, filename, strerror(errno));
close(fd);
if (err != raw_btf_size) {
fprintf(stderr, "%s: Could only write %d bytes to %s of raw BTF info out of %d, aborting\n", __func__, err, filename, raw_btf_size);
unlink(filename);
err = -1;
} else {
/* go from bytes written == raw_btf_size to an indication that all went fine */
err = 0;
}
return err;
}
static int btf__write_elf(struct btf *btf, const char *filename)
{
GElf_Shdr shdr_mem, *shdr;
GElf_Ehdr ehdr_mem, *ehdr;
Elf_Data *btf_data = NULL;
Elf_Scn *scn = NULL;
Elf *elf = NULL;
const void *raw_btf_data;
uint32_t raw_btf_size;
int fd, err = -1;
size_t strndx;
fd = open(filename, O_RDWR);
if (fd < 0) {
fprintf(stderr, "Cannot open %s\n", filename);
return -1;
}
if (elf_version(EV_CURRENT) == EV_NONE) {
elf_error("Cannot set libelf version");
goto out;
}
elf = elf_begin(fd, ELF_C_RDWR, NULL);
if (elf == NULL) {
elf_error("Cannot update ELF file");
goto out;
}
elf_flagelf(elf, ELF_C_SET, ELF_F_DIRTY);
ehdr = gelf_getehdr(elf, &ehdr_mem);
if (ehdr == NULL) {
elf_error("elf_getehdr failed");
goto out;
}
switch (ehdr_mem.e_ident[EI_DATA]) {
case ELFDATA2LSB:
btf__set_endianness(btf, BTF_LITTLE_ENDIAN);
break;
case ELFDATA2MSB:
btf__set_endianness(btf, BTF_BIG_ENDIAN);
break;
default:
fprintf(stderr, "%s: unknown ELF endianness.\n", __func__);
goto out;
}
/*
* First we look if there was already a .BTF section to overwrite.
*/
elf_getshdrstrndx(elf, &strndx);
while ((scn = elf_nextscn(elf, scn)) != NULL) {
shdr = gelf_getshdr(scn, &shdr_mem);
if (shdr == NULL)
continue;
char *secname = elf_strptr(elf, strndx, shdr->sh_name);
if (strcmp(secname, ".BTF") == 0) {
btf_data = elf_getdata(scn, btf_data);
break;
}
}
raw_btf_data = btf__get_raw_data(btf, &raw_btf_size);
if (btf_data) {
/* Existing .BTF section found */
btf_data->d_buf = (void *)raw_btf_data;
btf_data->d_size = raw_btf_size;
elf_flagdata(btf_data, ELF_C_SET, ELF_F_DIRTY);
if (elf_update(elf, ELF_C_NULL) >= 0 &&
elf_update(elf, ELF_C_WRITE) >= 0)
err = 0;
else
elf_error("elf_update failed");
} else {
const char *llvm_objcopy;
char tmp_fn[PATH_MAX];
char cmd[PATH_MAX * 2];
llvm_objcopy = getenv("LLVM_OBJCOPY");
if (!llvm_objcopy)
llvm_objcopy = "llvm-objcopy";
/* Use objcopy to add a .BTF section */
snprintf(tmp_fn, sizeof(tmp_fn), "%s.btf", filename);
close(fd);
fd = creat(tmp_fn, S_IRUSR | S_IWUSR);
if (fd == -1) {
fprintf(stderr, "%s: open(%s) failed!\n", __func__,
tmp_fn);
goto out;
}
if (write(fd, raw_btf_data, raw_btf_size) != raw_btf_size) {
fprintf(stderr, "%s: write of %d bytes to '%s' failed: %d!\n",
__func__, raw_btf_size, tmp_fn, errno);
goto unlink;
}
snprintf(cmd, sizeof(cmd), "%s --add-section .BTF=%s %s",
llvm_objcopy, tmp_fn, filename);
if (system(cmd)) {
fprintf(stderr, "%s: failed to add .BTF section to '%s': %d!\n",
__func__, filename, errno);
goto unlink;
}
err = 0;
unlink:
unlink(tmp_fn);
}
out:
if (fd != -1)
close(fd);
if (elf)
elf_end(elf);
return err;
}
int btf__encode_in_elf(struct btf *btf, const char *filename, uint8_t flags)
{
/* Empty file, nothing to do, so... done! */
if (btf__get_nr_types(btf) == 0)
return 0;
if (btf__dedup(btf, NULL, NULL)) {
fprintf(stderr, "%s: btf__dedup failed!\n", __func__);
return -1;
}
return btf__write_elf(btf, filename);
}
int btf_encoder__encode(struct btf_encoder *encoder, const char *detached_filename)
{