summaryrefslogtreecommitdiff
path: root/tools/bpf/bpftool/btf_dumper.c
blob: 6ba5f567a9d86778df796b3864c33b646d1db3de (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
// 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 <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/btf.h>
#include <linux/err.h>

#include "btf.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 void btf_dumper_ptr(const void *data, json_writer_t *jw,
			   bool is_plain_text)
{
	if (is_plain_text)
		jsonw_printf(jw, "%p", *(unsigned long *)data);
	else
		jsonw_printf(jw, "%u", *(unsigned long *)data);
}

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 void btf_dumper_enum(const void *data, json_writer_t *jw)
{
	jsonw_printf(jw, "%d", *(int *)data);
}

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;

	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_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;
	int bytes_to_copy;
	int bits_to_copy;
	__u64 print_num;

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

	print_num = 0;
	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 = 64 - bits_to_copy;
#else
#error neither big nor little endian
#endif
	right_shift_bits = 64 - nr_bits;

	print_num <<= left_shift_bits;
	print_num >>= right_shift_bits;
	if (is_plain_text)
		jsonw_printf(jw, "0x%llx", print_num);
	else
		jsonw_printf(jw, "%llu", print_num);
}


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 64 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;
	}

	switch (BTF_INT_ENCODING(*int_type)) {
	case 0:
		if (BTF_INT_BITS(*int_type) == 64)
			jsonw_printf(jw, "%lu", *(__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, "%ld", *(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_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:
		btf_dumper_enum(data, d->jw);
		return 0;
	case BTF_KIND_PTR:
		btf_dumper_ptr(data, d->jw, d->is_plain_text);
		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);
	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_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 __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_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:
		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_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);
			BTF_PRINT_ARG("%s",
				      btf__name_by_offset(btf, arg->name_off));
		} 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));
	}
}