summaryrefslogtreecommitdiff
path: root/tools/bpf/bpftool/xlated_dumper.c
blob: 3daa05d9bbb7337cecf1303174a3627fb88a0af9 (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
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2018 Netronome Systems, Inc. */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <bpf/libbpf.h>
#include <bpf/libbpf_internal.h>

#include "disasm.h"
#include "json_writer.h"
#include "main.h"
#include "xlated_dumper.h"

static int kernel_syms_cmp(const void *sym_a, const void *sym_b)
{
	return ((struct kernel_sym *)sym_a)->address -
	       ((struct kernel_sym *)sym_b)->address;
}

void kernel_syms_load(struct dump_data *dd)
{
	struct kernel_sym *sym;
	char buff[256];
	void *tmp, *address;
	FILE *fp;

	fp = fopen("/proc/kallsyms", "r");
	if (!fp)
		return;

	while (fgets(buff, sizeof(buff), fp)) {
		tmp = libbpf_reallocarray(dd->sym_mapping, dd->sym_count + 1,
					  sizeof(*dd->sym_mapping));
		if (!tmp) {
out:
			free(dd->sym_mapping);
			dd->sym_mapping = NULL;
			fclose(fp);
			return;
		}
		dd->sym_mapping = tmp;
		sym = &dd->sym_mapping[dd->sym_count];
		if (sscanf(buff, "%p %*c %s", &address, sym->name) != 2)
			continue;
		sym->address = (unsigned long)address;
		if (!strcmp(sym->name, "__bpf_call_base")) {
			dd->address_call_base = sym->address;
			/* sysctl kernel.kptr_restrict was set */
			if (!sym->address)
				goto out;
		}
		if (sym->address)
			dd->sym_count++;
	}

	fclose(fp);

	qsort(dd->sym_mapping, dd->sym_count,
	      sizeof(*dd->sym_mapping), kernel_syms_cmp);
}

void kernel_syms_destroy(struct dump_data *dd)
{
	free(dd->sym_mapping);
}

struct kernel_sym *kernel_syms_search(struct dump_data *dd,
				      unsigned long key)
{
	struct kernel_sym sym = {
		.address = key,
	};

	return dd->sym_mapping ?
	       bsearch(&sym, dd->sym_mapping, dd->sym_count,
		       sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL;
}

static void __printf(2, 3) print_insn(void *private_data, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	vprintf(fmt, args);
	va_end(args);
}

static void __printf(2, 3)
print_insn_for_graph(void *private_data, const char *fmt, ...)
{
	char buf[64], *p;
	va_list args;

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);

	p = buf;
	while (*p != '\0') {
		if (*p == '\n') {
			memmove(p + 3, p, strlen(buf) + 1 - (p - buf));
			/* Align each instruction dump row left. */
			*p++ = '\\';
			*p++ = 'l';
			/* Output multiline concatenation. */
			*p++ = '\\';
		} else if (*p == '<' || *p == '>' || *p == '|' || *p == '&') {
			memmove(p + 1, p, strlen(buf) + 1 - (p - buf));
			/* Escape special character. */
			*p++ = '\\';
		}

		p++;
	}

	printf("%s", buf);
}

static void __printf(2, 3)
print_insn_json(void *private_data, const char *fmt, ...)
{
	unsigned int l = strlen(fmt);
	char chomped_fmt[l];
	va_list args;

	va_start(args, fmt);
	if (l > 0) {
		strncpy(chomped_fmt, fmt, l - 1);
		chomped_fmt[l - 1] = '\0';
	}
	jsonw_vprintf_enquote(json_wtr, chomped_fmt, args);
	va_end(args);
}

static const char *print_call_pcrel(struct dump_data *dd,
				    struct kernel_sym *sym,
				    unsigned long address,
				    const struct bpf_insn *insn)
{
	if (!dd->nr_jited_ksyms)
		/* Do not show address for interpreted programs */
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			"%+d", insn->off);
	else if (sym)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "%+d#%s", insn->off, sym->name);
	else
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "%+d#0x%lx", insn->off, address);
	return dd->scratch_buff;
}

static const char *print_call_helper(struct dump_data *dd,
				     struct kernel_sym *sym,
				     unsigned long address)
{
	if (sym)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "%s", sym->name);
	else
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "0x%lx", address);
	return dd->scratch_buff;
}

static const char *print_call(void *private_data,
			      const struct bpf_insn *insn)
{
	struct dump_data *dd = private_data;
	unsigned long address = dd->address_call_base + insn->imm;
	struct kernel_sym *sym;

	if (insn->src_reg == BPF_PSEUDO_CALL &&
	    (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms)
		address = dd->jited_ksyms[insn->imm];

	sym = kernel_syms_search(dd, address);
	if (insn->src_reg == BPF_PSEUDO_CALL)
		return print_call_pcrel(dd, sym, address, insn);
	else
		return print_call_helper(dd, sym, address);
}

static const char *print_imm(void *private_data,
			     const struct bpf_insn *insn,
			     __u64 full_imm)
{
	struct dump_data *dd = private_data;

	if (insn->src_reg == BPF_PSEUDO_MAP_FD)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "map[id:%u]", insn->imm);
	else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
	else if (insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "map[idx:%u]+%u", insn->imm, (insn + 1)->imm);
	else if (insn->src_reg == BPF_PSEUDO_FUNC)
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "subprog[%+d]", insn->imm);
	else
		snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
			 "0x%llx", (unsigned long long)full_imm);
	return dd->scratch_buff;
}

void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len,
		      bool opcodes, bool linum)
{
	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
	const struct bpf_insn_cbs cbs = {
		.cb_print	= print_insn_json,
		.cb_call	= print_call,
		.cb_imm		= print_imm,
		.private_data	= dd,
	};
	struct bpf_func_info *record;
	struct bpf_insn *insn = buf;
	struct btf *btf = dd->btf;
	bool double_insn = false;
	unsigned int nr_skip = 0;
	char func_sig[1024];
	unsigned int i;

	jsonw_start_array(json_wtr);
	record = dd->func_info;
	for (i = 0; i < len / sizeof(*insn); i++) {
		if (double_insn) {
			double_insn = false;
			continue;
		}
		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);

		jsonw_start_object(json_wtr);

		if (btf && record) {
			if (record->insn_off == i) {
				btf_dumper_type_only(btf, record->type_id,
						     func_sig,
						     sizeof(func_sig));
				if (func_sig[0] != '\0') {
					jsonw_name(json_wtr, "proto");
					jsonw_string(json_wtr, func_sig);
				}
				record = (void *)record + dd->finfo_rec_size;
			}
		}

		if (prog_linfo) {
			const struct bpf_line_info *linfo;

			linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
			if (linfo) {
				btf_dump_linfo_json(btf, linfo, linum);
				nr_skip++;
			}
		}

		jsonw_name(json_wtr, "disasm");
		print_bpf_insn(&cbs, insn + i, true);

		if (opcodes) {
			jsonw_name(json_wtr, "opcodes");
			jsonw_start_object(json_wtr);

			jsonw_name(json_wtr, "code");
			jsonw_printf(json_wtr, "\"0x%02hhx\"", insn[i].code);

			jsonw_name(json_wtr, "src_reg");
			jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].src_reg);

			jsonw_name(json_wtr, "dst_reg");
			jsonw_printf(json_wtr, "\"0x%hhx\"", insn[i].dst_reg);

			jsonw_name(json_wtr, "off");
			print_hex_data_json((uint8_t *)(&insn[i].off), 2);

			jsonw_name(json_wtr, "imm");
			if (double_insn && i < len - 1)
				print_hex_data_json((uint8_t *)(&insn[i].imm),
						    12);
			else
				print_hex_data_json((uint8_t *)(&insn[i].imm),
						    4);
			jsonw_end_object(json_wtr);
		}
		jsonw_end_object(json_wtr);
	}
	jsonw_end_array(json_wtr);
}

void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len,
		       bool opcodes, bool linum)
{
	const struct bpf_prog_linfo *prog_linfo = dd->prog_linfo;
	const struct bpf_insn_cbs cbs = {
		.cb_print	= print_insn,
		.cb_call	= print_call,
		.cb_imm		= print_imm,
		.private_data	= dd,
	};
	struct bpf_func_info *record;
	struct bpf_insn *insn = buf;
	struct btf *btf = dd->btf;
	unsigned int nr_skip = 0;
	bool double_insn = false;
	char func_sig[1024];
	unsigned int i;

	record = dd->func_info;
	for (i = 0; i < len / sizeof(*insn); i++) {
		if (double_insn) {
			double_insn = false;
			continue;
		}

		if (btf && record) {
			if (record->insn_off == i) {
				btf_dumper_type_only(btf, record->type_id,
						     func_sig,
						     sizeof(func_sig));
				if (func_sig[0] != '\0')
					printf("%s:\n", func_sig);
				record = (void *)record + dd->finfo_rec_size;
			}
		}

		if (prog_linfo) {
			const struct bpf_line_info *linfo;

			linfo = bpf_prog_linfo__lfind(prog_linfo, i, nr_skip);
			if (linfo) {
				btf_dump_linfo_plain(btf, linfo, "; ",
						     linum);
				nr_skip++;
			}
		}

		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);

		printf("% 4d: ", i);
		print_bpf_insn(&cbs, insn + i, true);

		if (opcodes) {
			printf("       ");
			fprint_hex(stdout, insn + i, 8, " ");
			if (double_insn && i < len - 1) {
				printf(" ");
				fprint_hex(stdout, insn + i + 1, 8, " ");
			}
			printf("\n");
		}
	}
}

void dump_xlated_for_graph(struct dump_data *dd, void *buf_start, void *buf_end,
			   unsigned int start_idx)
{
	const struct bpf_insn_cbs cbs = {
		.cb_print	= print_insn_for_graph,
		.cb_call	= print_call,
		.cb_imm		= print_imm,
		.private_data	= dd,
	};
	struct bpf_insn *insn_start = buf_start;
	struct bpf_insn *insn_end = buf_end;
	struct bpf_insn *cur = insn_start;
	bool double_insn = false;

	for (; cur <= insn_end; cur++) {
		if (double_insn) {
			double_insn = false;
			continue;
		}
		double_insn = cur->code == (BPF_LD | BPF_IMM | BPF_DW);

		printf("% 4d: ", (int)(cur - insn_start + start_idx));
		print_bpf_insn(&cbs, cur, true);
		if (cur != insn_end)
			printf(" | ");
	}
}