summaryrefslogtreecommitdiff
path: root/tools/bpf/bpftool/btf_dumper.c
blob: f5dddf8ef404b1eec57218e8eeba847d068d9061 (plain)
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
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */

#include <ctype.h>
#include <stdio.h> /* for (FILE *) used by json_writer */
#include <string.h>
#include <unistd.h>
#include <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <bpf/btf.h>
#include <bpf/bpf.h>

#include "json_writer.h"
#include "main.h"

#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 int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
			      __u8 bit_offset, const void *data);

static int btf_dump_func(const struct btf *btf, char *func_sig,
			 const struct btf_type *func_proto,
			 const struct btf_type *func, int pos, int size);

static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
				    const struct btf_type *func_proto,
				    __u32 prog_id)
{
	const struct btf_type *func_type;
	int prog_fd = -1, func_sig_len;
	struct bpf_prog_info info = {};
	__u32 info_len = sizeof(info);
	const char *prog_name = NULL;
	struct btf *prog_btf = NULL;
	struct bpf_func_info finfo;
	__u32 finfo_rec_size;
	char prog_str[1024];
	int err;

	/* Get the ptr's func_proto */
	func_sig_len = btf_dump_func(d->btf, prog_str, func_proto, NULL, 0,
				     sizeof(prog_str));
	if (func_sig_len == -1)
		return -1;

	if (!prog_id)
		goto print;

	/* Get the bpf_prog's name.  Obtain from func_info. */
	prog_fd = bpf_prog_get_fd_by_id(prog_id);
	if (prog_fd < 0)
		goto print;

	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
	if (err)
		goto print;

	if (!info.btf_id || !info.nr_func_info)
		goto print;

	finfo_rec_size = info.func_info_rec_size;
	memset(&info, 0, sizeof(info));
	info.nr_func_info = 1;
	info.func_info_rec_size = finfo_rec_size;
	info.func_info = ptr_to_u64(&finfo);

	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
	if (err)
		goto print;

	prog_btf = btf__load_from_kernel_by_id(info.btf_id);
	if (libbpf_get_error(prog_btf))
		goto print;
	func_type = btf__type_by_id(prog_btf, finfo.type_id);
	if (!func_type || !btf_is_func(func_type))
		goto print;

	prog_name = btf__name_by_offset(prog_btf, func_type->name_off);

print:
	if (!prog_id)
		snprintf(&prog_str[func_sig_len],
			 sizeof(prog_str) - func_sig_len, " 0");
	else if (prog_name)
		snprintf(&prog_str[func_sig_len],
			 sizeof(prog_str) - func_sig_len,
			 " %s/prog_id:%u", prog_name, prog_id);
	else
		snprintf(&prog_str[func_sig_len],
			 sizeof(prog_str) - func_sig_len,
			 " <unknown_prog_name>/prog_id:%u", prog_id);

	prog_str[sizeof(prog_str) - 1] = '\0';
	jsonw_string(d->jw, prog_str);
	btf__free(prog_btf);
	if (prog_fd >= 0)
		close(prog_fd);
	return 0;
}

static void btf_dumper_ptr(const struct btf_dumper *d,
			   const struct btf_type *t,
			   const void *data)
{
	unsigned long value = *(unsigned long *)data;
	const struct btf_type *ptr_type;
	__s32 ptr_type_id;

	if (!d->prog_id_as_func_ptr || value > UINT32_MAX)
		goto print_ptr_value;

	ptr_type_id = btf__resolve_type(d->btf, t->type);
	if (ptr_type_id < 0)
		goto print_ptr_value;
	ptr_type = btf__type_by_id(d->btf, ptr_type_id);
	if (!ptr_type || !btf_is_func_proto(ptr_type))
		goto print_ptr_value;

	if (!dump_prog_id_as_func_ptr(d, ptr_type, value))
		return;

print_ptr_value:
	if (d->is_plain_text)
		jsonw_printf(d->jw, "%p", (void *)value);
	else
		jsonw_printf(d->jw, "%lu", value);
}

static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
			       __u8 bit_offset, const void *data)
{
	int actual_type_id;

	actual_type_id = btf__resolve_type(d->btf, type_id);
	if (actual_type_id < 0)
		return actual_type_id;

	return btf_dumper_do_type(d, actual_type_id, bit_offset, data);
}

static int btf_dumper_enum(const struct btf_dumper *d,
			    const struct btf_type *t,
			    const void *data)
{
	const struct btf_enum *enums = btf_enum(t);
	__s64 value;
	__u16 i;

	switch (t->size) {
	case 8:
		value = *(__s64 *)data;
		break;
	case 4:
		value = *(__s32 *)data;
		break;
	case 2:
		value = *(__s16 *)data;
		break;
	case 1:
		value = *(__s8 *)data;
		break;
	default:
		return -EINVAL;
	}

	for (i = 0; i < btf_vlen(t); i++) {
		if (value == enums[i].val) {
			jsonw_string(d->jw,
				     btf__name_by_offset(d->btf,
							 enums[i].name_off));
			return 0;
		}
	}

	jsonw_int(d->jw, value);
	return 0;
}

static bool is_str_array(const struct btf *btf, const struct btf_array *arr,
			 const char *s)
{
	const struct btf_type *elem_type;
	const char *end_s;

	if (!arr->nelems)
		return false;

	elem_type = btf__type_by_id(btf, arr->type);
	/* Not skipping typedef.  typedef to char does not count as
	 * a string now.
	 */
	while (elem_type && btf_is_mod(elem_type))
		elem_type = btf__type_by_id(btf, elem_type->type);

	if (!elem_type || !btf_is_int(elem_type) || elem_type->size != 1)
		return false;

	if (btf_int_encoding(elem_type) != BTF_INT_CHAR &&
	    strcmp("char", btf__name_by_offset(btf, elem_type->name_off)))
		return false;

	end_s = s + arr->nelems;
	while (s < end_s) {
		if (!*s)
			return true;
		if (*s <= 0x1f || *s >= 0x7f)
			return false;
		s++;
	}

	/* '\0' is not found */
	return false;
}

static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
			    const void *data)
{
	const struct btf_type *t = btf__type_by_id(d->btf, type_id);
	struct btf_array *arr = (struct btf_array *)(t + 1);
	long long elem_size;
	int ret = 0;
	__u32 i;

	if (is_str_array(d->btf, arr, data)) {
		jsonw_string(d->jw, data);
		return 0;
	}

	elem_size = btf__resolve_size(d->btf, arr->type);
	if (elem_size < 0)
		return elem_size;

	jsonw_start_array(d->jw);
	for (i = 0; i < arr->nelems; i++) {
		ret = btf_dumper_do_type(d, arr->type, 0,
					 data + i * elem_size);
		if (ret)
			break;
	}

	jsonw_end_array(d->jw);
	return ret;
}

static void btf_int128_print(json_writer_t *jw, const void *data,
			     bool is_plain_text)
{
	/* data points to a __int128 number.
	 * Suppose
	 *     int128_num = *(__int128 *)data;
	 * The below formulas shows what upper_num and lower_num represents:
	 *     upper_num = int128_num >> 64;
	 *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
	 */
	__u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
	upper_num = *(__u64 *)data;
	lower_num = *(__u64 *)(data + 8);
#else
	upper_num = *(__u64 *)(data + 8);
	lower_num = *(__u64 *)data;
#endif

	if (is_plain_text) {
		if (upper_num == 0)
			jsonw_printf(jw, "0x%llx", lower_num);
		else
			jsonw_printf(jw, "0x%llx%016llx", upper_num, lower_num);
	} else {
		if (upper_num == 0)
			jsonw_printf(jw, "\"0x%llx\"", lower_num);
		else
			jsonw_printf(jw, "\"0x%llx%016llx\"", upper_num, lower_num);
	}
}

static void btf_int128_shift(__u64 *print_num, __u16 left_shift_bits,
			     __u16 right_shift_bits)
{
	__u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
	upper_num = print_num[0];
	lower_num = print_num[1];
#else
	upper_num = print_num[1];
	lower_num = print_num[0];
#endif

	/* shake out un-needed bits by shift/or operations */
	if (left_shift_bits >= 64) {
		upper_num = lower_num << (left_shift_bits - 64);
		lower_num = 0;
	} else {
		upper_num = (upper_num << left_shift_bits) |
			    (lower_num >> (64 - left_shift_bits));
		lower_num = lower_num << left_shift_bits;
	}

	if (right_shift_bits >= 64) {
		lower_num = upper_num >> (right_shift_bits - 64);
		upper_num = 0;
	} else {
		lower_num = (lower_num >> right_shift_bits) |
			    (upper_num << (64 - right_shift_bits));
		upper_num = upper_num >> right_shift_bits;
	}

#ifdef __BIG_ENDIAN_BITFIELD
	print_num[0] = upper_num;
	print_num[1] = lower_num;
#else
	print_num[0] = lower_num;
	print_num[1] = upper_num;
#endif
}

static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
				const void *data, json_writer_t *jw,
				bool is_plain_text)
{
	int left_shift_bits, right_shift_bits;
	__u64 print_num[2] = {};
	int bytes_to_copy;
	int bits_to_copy;

	bits_to_copy = bit_offset + nr_bits;
	bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);

	memcpy(print_num, data, bytes_to_copy);
#if defined(__BIG_ENDIAN_BITFIELD)
	left_shift_bits = bit_offset;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
	left_shift_bits = 128 - bits_to_copy;
#else
#error neither big nor little endian
#endif
	right_shift_bits = 128 - nr_bits;

	btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
	btf_int128_print(jw, print_num, is_plain_text);
}


static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
				const void *data, json_writer_t *jw,
				bool is_plain_text)
{
	int nr_bits = BTF_INT_BITS(int_type);
	int total_bits_offset;

	/* bits_offset is at most 7.
	 * BTF_INT_OFFSET() cannot exceed 128 bits.
	 */
	total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
	data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
	bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
	btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
			    is_plain_text);
}

static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
			  const void *data, json_writer_t *jw,
			  bool is_plain_text)
{
	__u32 *int_type;
	__u32 nr_bits;

	int_type = (__u32 *)(t + 1);
	nr_bits = BTF_INT_BITS(*int_type);
	/* if this is bit field */
	if (bit_offset || BTF_INT_OFFSET(*int_type) ||
	    BITS_PER_BYTE_MASKED(nr_bits)) {
		btf_dumper_int_bits(*int_type, bit_offset, data, jw,
				    is_plain_text);
		return 0;
	}

	if (nr_bits == 128) {
		btf_int128_print(jw, data, is_plain_text);
		return 0;
	}

	switch (BTF_INT_ENCODING(*int_type)) {
	case 0:
		if (BTF_INT_BITS(*int_type) == 64)
			jsonw_printf(jw, "%llu", *(__u64 *)data);
		else if (BTF_INT_BITS(*int_type) == 32)
			jsonw_printf(jw, "%u", *(__u32 *)data);
		else if (BTF_INT_BITS(*int_type) == 16)
			jsonw_printf(jw, "%hu", *(__u16 *)data);
		else if (BTF_INT_BITS(*int_type) == 8)
			jsonw_printf(jw, "%hhu", *(__u8 *)data);
		else
			btf_dumper_int_bits(*int_type, bit_offset, data, jw,
					    is_plain_text);
		break;
	case BTF_INT_SIGNED:
		if (BTF_INT_BITS(*int_type) == 64)
			jsonw_printf(jw, "%lld", *(long long *)data);
		else if (BTF_INT_BITS(*int_type) == 32)
			jsonw_printf(jw, "%d", *(int *)data);
		else if (BTF_INT_BITS(*int_type) == 16)
			jsonw_printf(jw, "%hd", *(short *)data);
		else if (BTF_INT_BITS(*int_type) == 8)
			jsonw_printf(jw, "%hhd", *(char *)data);
		else
			btf_dumper_int_bits(*int_type, bit_offset, data, jw,
					    is_plain_text);
		break;
	case BTF_INT_CHAR:
		if (isprint(*(char *)data))
			jsonw_printf(jw, "\"%c\"", *(char *)data);
		else
			if (is_plain_text)
				jsonw_printf(jw, "0x%hhx", *(char *)data);
			else
				jsonw_printf(jw, "\"\\u00%02hhx\"",
					     *(char *)data);
		break;
	case BTF_INT_BOOL:
		jsonw_bool(jw, *(int *)data);
		break;
	default:
		/* shouldn't happen */
		return -EINVAL;
	}

	return 0;
}

static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
			     const void *data)
{
	const struct btf_type *t;
	struct btf_member *m;
	const void *data_off;
	int kind_flag;
	int ret = 0;
	int i, vlen;

	t = btf__type_by_id(d->btf, type_id);
	if (!t)
		return -EINVAL;

	kind_flag = BTF_INFO_KFLAG(t->info);
	vlen = BTF_INFO_VLEN(t->info);
	jsonw_start_object(d->jw);
	m = (struct btf_member *)(t + 1);

	for (i = 0; i < vlen; i++) {
		__u32 bit_offset = m[i].offset;
		__u32 bitfield_size = 0;

		if (kind_flag) {
			bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
			bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
		}

		jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
		data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
		if (bitfield_size) {
			btf_dumper_bitfield(bitfield_size,
					    BITS_PER_BYTE_MASKED(bit_offset),
					    data_off, d->jw, d->is_plain_text);
		} else {
			ret = btf_dumper_do_type(d, m[i].type,
						 BITS_PER_BYTE_MASKED(bit_offset),
						 data_off);
			if (ret)
				break;
		}
	}

	jsonw_end_object(d->jw);

	return ret;
}

static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
			  __u8 bit_offset, const void *data)
{
	const struct btf_type *t = btf__type_by_id(d->btf, type_id);
	int ret;

	jsonw_start_object(d->jw);
	jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
	ret = btf_dumper_do_type(d, t->type, bit_offset, data);
	jsonw_end_object(d->jw);

	return ret;
}

static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
			      const void *data)
{
	struct btf_var_secinfo *vsi;
	const struct btf_type *t;
	int ret = 0, i, vlen;

	t = btf__type_by_id(d->btf, type_id);
	if (!t)
		return -EINVAL;

	vlen = BTF_INFO_VLEN(t->info);
	vsi = (struct btf_var_secinfo *)(t + 1);

	jsonw_start_object(d->jw);
	jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
	jsonw_start_array(d->jw);
	for (i = 0; i < vlen; i++) {
		ret = btf_dumper_do_type(d, vsi[i].type, 0, data + vsi[i].offset);
		if (ret)
			break;
	}
	jsonw_end_array(d->jw);
	jsonw_end_object(d->jw);

	return ret;
}

static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
			      __u8 bit_offset, const void *data)
{
	const struct btf_type *t = btf__type_by_id(d->btf, type_id);

	switch (BTF_INFO_KIND(t->info)) {
	case BTF_KIND_INT:
		return btf_dumper_int(t, bit_offset, data, d->jw,
				     d->is_plain_text);
	case BTF_KIND_STRUCT:
	case BTF_KIND_UNION:
		return btf_dumper_struct(d, type_id, data);
	case BTF_KIND_ARRAY:
		return btf_dumper_array(d, type_id, data);
	case BTF_KIND_ENUM:
		return btf_dumper_enum(d, t, data);
	case BTF_KIND_PTR:
		btf_dumper_ptr(d, t, data);
		return 0;
	case BTF_KIND_UNKN:
		jsonw_printf(d->jw, "(unknown)");
		return 0;
	case BTF_KIND_FWD:
		/* map key or value can't be forward */
		jsonw_printf(d->jw, "(fwd-kind-invalid)");
		return -EINVAL;
	case BTF_KIND_TYPEDEF:
	case BTF_KIND_VOLATILE:
	case BTF_KIND_CONST:
	case BTF_KIND_RESTRICT:
		return btf_dumper_modifier(d, type_id, bit_offset, data);
	case BTF_KIND_VAR:
		return btf_dumper_var(d, type_id, bit_offset, data);
	case BTF_KIND_DATASEC:
		return btf_dumper_datasec(d, type_id, data);
	default:
		jsonw_printf(d->jw, "(unsupported-kind");
		return -EINVAL;
	}
}

int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
		    const void *data)
{
	return btf_dumper_do_type(d, type_id, 0, data);
}

#define BTF_PRINT_ARG(...)						\
	do {								\
		pos += snprintf(func_sig + pos, size - pos,		\
				__VA_ARGS__);				\
		if (pos >= size)					\
			return -1;					\
	} while (0)
#define BTF_PRINT_TYPE(type)					\
	do {								\
		pos = __btf_dumper_type_only(btf, type, func_sig,	\
					     pos, size);		\
		if (pos == -1)						\
			return -1;					\
	} while (0)

static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
				  char *func_sig, int pos, int size)
{
	const struct btf_type *proto_type;
	const struct btf_array *array;
	const struct btf_var *var;
	const struct btf_type *t;

	if (!type_id) {
		BTF_PRINT_ARG("void ");
		return pos;
	}

	t = btf__type_by_id(btf, type_id);

	switch (BTF_INFO_KIND(t->info)) {
	case BTF_KIND_INT:
	case BTF_KIND_TYPEDEF:
	case BTF_KIND_FLOAT:
		BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_STRUCT:
		BTF_PRINT_ARG("struct %s ",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_UNION:
		BTF_PRINT_ARG("union %s ",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_ENUM:
		BTF_PRINT_ARG("enum %s ",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_ARRAY:
		array = (struct btf_array *)(t + 1);
		BTF_PRINT_TYPE(array->type);
		BTF_PRINT_ARG("[%d]", array->nelems);
		break;
	case BTF_KIND_PTR:
		BTF_PRINT_TYPE(t->type);
		BTF_PRINT_ARG("* ");
		break;
	case BTF_KIND_FWD:
		BTF_PRINT_ARG("%s %s ",
			      BTF_INFO_KFLAG(t->info) ? "union" : "struct",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_VOLATILE:
		BTF_PRINT_ARG("volatile ");
		BTF_PRINT_TYPE(t->type);
		break;
	case BTF_KIND_CONST:
		BTF_PRINT_ARG("const ");
		BTF_PRINT_TYPE(t->type);
		break;
	case BTF_KIND_RESTRICT:
		BTF_PRINT_ARG("restrict ");
		BTF_PRINT_TYPE(t->type);
		break;
	case BTF_KIND_FUNC_PROTO:
		pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);
		if (pos == -1)
			return -1;
		break;
	case BTF_KIND_FUNC:
		proto_type = btf__type_by_id(btf, t->type);
		pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);
		if (pos == -1)
			return -1;
		break;
	case BTF_KIND_VAR:
		var = (struct btf_var *)(t + 1);
		if (var->linkage == BTF_VAR_STATIC)
			BTF_PRINT_ARG("static ");
		BTF_PRINT_TYPE(t->type);
		BTF_PRINT_ARG(" %s",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_DATASEC:
		BTF_PRINT_ARG("section (\"%s\") ",
			      btf__name_by_offset(btf, t->name_off));
		break;
	case BTF_KIND_UNKN:
	default:
		return -1;
	}

	return pos;
}

static int btf_dump_func(const struct btf *btf, char *func_sig,
			 const struct btf_type *func_proto,
			 const struct btf_type *func, int pos, int size)
{
	int i, vlen;

	BTF_PRINT_TYPE(func_proto->type);
	if (func)
		BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
	else
		BTF_PRINT_ARG("(");
	vlen = BTF_INFO_VLEN(func_proto->info);
	for (i = 0; i < vlen; i++) {
		struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];

		if (i)
			BTF_PRINT_ARG(", ");
		if (arg->type) {
			BTF_PRINT_TYPE(arg->type);
			if (arg->name_off)
				BTF_PRINT_ARG("%s",
					      btf__name_by_offset(btf, arg->name_off));
			else if (pos && func_sig[pos - 1] == ' ')
				/* Remove unnecessary space for
				 * FUNC_PROTO that does not have
				 * arg->name_off
				 */
				func_sig[--pos] = '\0';
		} else {
			BTF_PRINT_ARG("...");
		}
	}
	BTF_PRINT_ARG(")");

	return pos;
}

void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
			  int size)
{
	int err;

	func_sig[0] = '\0';
	if (!btf)
		return;

	err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);
	if (err < 0)
		func_sig[0] = '\0';
}

static const char *ltrim(const char *s)
{
	while (isspace(*s))
		s++;

	return s;
}

void btf_dump_linfo_plain(const struct btf *btf,
			  const struct bpf_line_info *linfo,
			  const char *prefix, bool linum)
{
	const char *line = btf__name_by_offset(btf, linfo->line_off);

	if (!line)
		return;
	line = ltrim(line);

	if (!prefix)
		prefix = "";

	if (linum) {
		const char *file = btf__name_by_offset(btf, linfo->file_name_off);

		/* More forgiving on file because linum option is
		 * expected to provide more info than the already
		 * available src line.
		 */
		if (!file)
			file = "";

		printf("%s%s [file:%s line_num:%u line_col:%u]\n",
		       prefix, line, file,
		       BPF_LINE_INFO_LINE_NUM(linfo->line_col),
		       BPF_LINE_INFO_LINE_COL(linfo->line_col));
	} else {
		printf("%s%s\n", prefix, line);
	}
}

void btf_dump_linfo_json(const struct btf *btf,
			 const struct bpf_line_info *linfo, bool linum)
{
	const char *line = btf__name_by_offset(btf, linfo->line_off);

	if (line)
		jsonw_string_field(json_wtr, "src", ltrim(line));

	if (linum) {
		const char *file = btf__name_by_offset(btf, linfo->file_name_off);

		if (file)
			jsonw_string_field(json_wtr, "file", file);

		if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
			jsonw_int_field(json_wtr, "line_num",
					BPF_LINE_INFO_LINE_NUM(linfo->line_col));

		if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
			jsonw_int_field(json_wtr, "line_col",
					BPF_LINE_INFO_LINE_COL(linfo->line_col));
	}
}