aboutsummaryrefslogtreecommitdiff
path: root/tools/perf/util/probe-event.c
blob: 1653a62a478e91b4a9a6dbc1940656f6d1b94a86 (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
/*
 * probe-event.c : perf-probe definition to kprobe_events format converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#define _GNU_SOURCE
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <limits.h>

#undef _GNU_SOURCE
#include "event.h"
#include "string.h"
#include "strlist.h"
#include "debug.h"
#include "parse-events.h"  /* For debugfs_path */
#include "probe-event.h"

#define MAX_CMDLEN 256
#define MAX_PROBE_ARGS 128
#define PERFPROBE_GROUP "probe"

#define semantic_error(msg ...) die("Semantic error :" msg)

/* If there is no space to write, returns -E2BIG. */
static int e_snprintf(char *str, size_t size, const char *format, ...)
	__attribute__((format(printf, 3, 4)));

static int e_snprintf(char *str, size_t size, const char *format, ...)
{
	int ret;
	va_list ap;
	va_start(ap, format);
	ret = vsnprintf(str, size, format, ap);
	va_end(ap);
	if (ret >= (int)size)
		ret = -E2BIG;
	return ret;
}

/* Parse probepoint definition. */
static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
{
	char *ptr, *tmp;
	char c, nc = 0;
	/*
	 * <Syntax>
	 * perf probe SRC:LN
	 * perf probe FUNC[+OFFS|%return][@SRC]
	 */

	ptr = strpbrk(arg, ":+@%");
	if (ptr) {
		nc = *ptr;
		*ptr++ = '\0';
	}

	/* Check arg is function or file and copy it */
	if (strchr(arg, '.'))	/* File */
		pp->file = strdup(arg);
	else			/* Function */
		pp->function = strdup(arg);
	DIE_IF(pp->file == NULL && pp->function == NULL);

	/* Parse other options */
	while (ptr) {
		arg = ptr;
		c = nc;
		ptr = strpbrk(arg, ":+@%");
		if (ptr) {
			nc = *ptr;
			*ptr++ = '\0';
		}
		switch (c) {
		case ':':	/* Line number */
			pp->line = strtoul(arg, &tmp, 0);
			if (*tmp != '\0')
				semantic_error("There is non-digit charactor"
						" in line number.");
			break;
		case '+':	/* Byte offset from a symbol */
			pp->offset = strtoul(arg, &tmp, 0);
			if (*tmp != '\0')
				semantic_error("There is non-digit charactor"
						" in offset.");
			break;
		case '@':	/* File name */
			if (pp->file)
				semantic_error("SRC@SRC is not allowed.");
			pp->file = strdup(arg);
			DIE_IF(pp->file == NULL);
			if (ptr)
				semantic_error("@SRC must be the last "
					       "option.");
			break;
		case '%':	/* Probe places */
			if (strcmp(arg, "return") == 0) {
				pp->retprobe = 1;
			} else	/* Others not supported yet */
				semantic_error("%%%s is not supported.", arg);
			break;
		default:
			DIE_IF("Program has a bug.");
			break;
		}
	}

	/* Exclusion check */
	if (pp->line && pp->offset)
		semantic_error("Offset can't be used with line number.");

	if (!pp->line && pp->file && !pp->function)
		semantic_error("File always requires line number.");

	if (pp->offset && !pp->function)
		semantic_error("Offset requires an entry function.");

	if (pp->retprobe && !pp->function)
		semantic_error("Return probe requires an entry function.");

	if ((pp->offset || pp->line) && pp->retprobe)
		semantic_error("Offset/Line can't be used with return probe.");

	pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
		 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
}

/* Parse perf-probe event definition */
void parse_perf_probe_event(const char *str, struct probe_point *pp,
			    bool *need_dwarf)
{
	char **argv;
	int argc, i;

	*need_dwarf = false;

	argv = argv_split(str, &argc);
	if (!argv)
		die("argv_split failed.");
	if (argc > MAX_PROBE_ARGS + 1)
		semantic_error("Too many arguments");

	/* Parse probe point */
	parse_perf_probe_probepoint(argv[0], pp);
	if (pp->file || pp->line)
		*need_dwarf = true;

	/* Copy arguments and ensure return probe has no C argument */
	pp->nr_args = argc - 1;
	pp->args = zalloc(sizeof(char *) * pp->nr_args);
	for (i = 0; i < pp->nr_args; i++) {
		pp->args[i] = strdup(argv[i + 1]);
		if (!pp->args[i])
			die("Failed to copy argument.");
		if (is_c_varname(pp->args[i])) {
			if (pp->retprobe)
				semantic_error("You can't specify local"
						" variable for kretprobe");
			*need_dwarf = true;
		}
	}

	argv_free(argv);
}

/* Parse kprobe_events event into struct probe_point */
void parse_trace_kprobe_event(const char *str, char **group, char **event,
			      struct probe_point *pp)
{
	char pr;
	char *p;
	int ret, i, argc;
	char **argv;

	pr_debug("Parsing kprobe_events: %s\n", str);
	argv = argv_split(str, &argc);
	if (!argv)
		die("argv_split failed.");
	if (argc < 2)
		semantic_error("Too less arguments.");

	/* Scan event and group name. */
	ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
		     &pr, (float *)(void *)group, (float *)(void *)event);
	if (ret != 3)
		semantic_error("Failed to parse event name: %s", argv[0]);
	pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr);

	if (!pp)
		goto end;

	pp->retprobe = (pr == 'r');

	/* Scan function name and offset */
	ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function, &pp->offset);
	if (ret == 1)
		pp->offset = 0;

	/* kprobe_events doesn't have this information */
	pp->line = 0;
	pp->file = NULL;

	pp->nr_args = argc - 2;
	pp->args = zalloc(sizeof(char *) * pp->nr_args);
	for (i = 0; i < pp->nr_args; i++) {
		p = strchr(argv[i + 2], '=');
		if (p)	/* We don't need which register is assigned. */
			*p = '\0';
		pp->args[i] = strdup(argv[i + 2]);
		if (!pp->args[i])
			die("Failed to copy argument.");
	}

end:
	argv_free(argv);
}

int synthesize_perf_probe_event(struct probe_point *pp)
{
	char *buf;
	char offs[64] = "", line[64] = "";
	int i, len, ret;

	pp->probes[0] = buf = zalloc(MAX_CMDLEN);
	if (!buf)
		die("Failed to allocate memory by zalloc.");
	if (pp->offset) {
		ret = e_snprintf(offs, 64, "+%d", pp->offset);
		if (ret <= 0)
			goto error;
	}
	if (pp->line) {
		ret = e_snprintf(line, 64, ":%d", pp->line);
		if (ret <= 0)
			goto error;
	}

	if (pp->function)
		ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
				 offs, pp->retprobe ? "%return" : "", line);
	else
		ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", pp->file, line);
	if (ret <= 0)
		goto error;
	len = ret;

	for (i = 0; i < pp->nr_args; i++) {
		ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
				 pp->args[i]);
		if (ret <= 0)
			goto error;
		len += ret;
	}
	pp->found = 1;

	return pp->found;
error:
	free(pp->probes[0]);

	return ret;
}

int synthesize_trace_kprobe_event(struct probe_point *pp)
{
	char *buf;
	int i, len, ret;

	pp->probes[0] = buf = zalloc(MAX_CMDLEN);
	if (!buf)
		die("Failed to allocate memory by zalloc.");
	ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
	if (ret <= 0)
		goto error;
	len = ret;

	for (i = 0; i < pp->nr_args; i++) {
		ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
				 pp->args[i]);
		if (ret <= 0)
			goto error;
		len += ret;
	}
	pp->found = 1;

	return pp->found;
error:
	free(pp->probes[0]);

	return ret;
}

static int open_kprobe_events(int flags, int mode)
{
	char buf[PATH_MAX];
	int ret;

	ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
	if (ret < 0)
		die("Failed to make kprobe_events path.");

	ret = open(buf, flags, mode);
	if (ret < 0) {
		if (errno == ENOENT)
			die("kprobe_events file does not exist -"
			    " please rebuild with CONFIG_KPROBE_TRACER.");
		else
			die("Could not open kprobe_events file: %s",
			    strerror(errno));
	}
	return ret;
}

/* Get raw string list of current kprobe_events */
static struct strlist *get_trace_kprobe_event_rawlist(int fd)
{
	int ret, idx;
	FILE *fp;
	char buf[MAX_CMDLEN];
	char *p;
	struct strlist *sl;

	sl = strlist__new(true, NULL);

	fp = fdopen(dup(fd), "r");
	while (!feof(fp)) {
		p = fgets(buf, MAX_CMDLEN, fp);
		if (!p)
			break;

		idx = strlen(p) - 1;
		if (p[idx] == '\n')
			p[idx] = '\0';
		ret = strlist__add(sl, buf);
		if (ret < 0)
			die("strlist__add failed: %s", strerror(-ret));
	}
	fclose(fp);

	return sl;
}

/* Free and zero clear probe_point */
static void clear_probe_point(struct probe_point *pp)
{
	int i;

	if (pp->function)
		free(pp->function);
	if (pp->file)
		free(pp->file);
	for (i = 0; i < pp->nr_args; i++)
		free(pp->args[i]);
	if (pp->args)
		free(pp->args);
	for (i = 0; i < pp->found; i++)
		free(pp->probes[i]);
	memset(pp, 0, sizeof(*pp));
}

/* Show an event */
static void show_perf_probe_event(const char *group, const char *event,
				  const char *place, struct probe_point *pp)
{
	int i, ret;
	char buf[128];

	ret = e_snprintf(buf, 128, "%s:%s", group, event);
	if (ret < 0)
		die("Failed to copy event: %s", strerror(-ret));
	printf("  %-40s (on %s", buf, place);

	if (pp->nr_args > 0) {
		printf(" with");
		for (i = 0; i < pp->nr_args; i++)
			printf(" %s", pp->args[i]);
	}
	printf(")\n");
}

/* List up current perf-probe events */
void show_perf_probe_events(void)
{
	unsigned int i;
	int fd, nr;
	char *group, *event;
	struct probe_point pp;
	struct strlist *rawlist;
	struct str_node *ent;

	fd = open_kprobe_events(O_RDONLY, 0);
	rawlist = get_trace_kprobe_event_rawlist(fd);
	close(fd);

	for (i = 0; i < strlist__nr_entries(rawlist); i++) {
		ent = strlist__entry(rawlist, i);
		parse_trace_kprobe_event(ent->s, &group, &event, &pp);
		/* Synthesize only event probe point */
		nr = pp.nr_args;
		pp.nr_args = 0;
		synthesize_perf_probe_event(&pp);
		pp.nr_args = nr;
		/* Show an event */
		show_perf_probe_event(group, event, pp.probes[0], &pp);
		free(group);
		free(event);
		clear_probe_point(&pp);
	}

	strlist__delete(rawlist);
}

/* Get current perf-probe event names */
static struct strlist *get_perf_event_names(int fd, bool include_group)
{
	unsigned int i;
	char *group, *event;
	char buf[128];
	struct strlist *sl, *rawlist;
	struct str_node *ent;

	rawlist = get_trace_kprobe_event_rawlist(fd);

	sl = strlist__new(true, NULL);
	for (i = 0; i < strlist__nr_entries(rawlist); i++) {
		ent = strlist__entry(rawlist, i);
		parse_trace_kprobe_event(ent->s, &group, &event, NULL);
		if (include_group) {
			if (e_snprintf(buf, 128, "%s:%s", group, event) < 0)
				die("Failed to copy group:event name.");
			strlist__add(sl, buf);
		} else
			strlist__add(sl, event);
		free(group);
		free(event);
	}

	strlist__delete(rawlist);

	return sl;
}

static void write_trace_kprobe_event(int fd, const char *buf)
{
	int ret;

	pr_debug("Writing event: %s\n", buf);
	ret = write(fd, buf, strlen(buf));
	if (ret <= 0)
		die("Failed to write event: %s", strerror(errno));
}

static void get_new_event_name(char *buf, size_t len, const char *base,
			       struct strlist *namelist)
{
	int i, ret;

	/* Try no suffix */
	ret = e_snprintf(buf, len, "%s", base);
	if (ret < 0)
		die("snprintf() failed: %s", strerror(-ret));
	if (!strlist__has_entry(namelist, buf))
		return;

	/* Try to add suffix */
	for (i = 1; i < MAX_EVENT_INDEX; i++) {
		ret = e_snprintf(buf, len, "%s_%d", base, i);
		if (ret < 0)
			die("snprintf() failed: %s", strerror(-ret));
		if (!strlist__has_entry(namelist, buf))
			break;
	}
	if (i == MAX_EVENT_INDEX)
		die("Too many events are on the same function.");
}

void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
{
	int i, j, fd;
	struct probe_point *pp;
	char buf[MAX_CMDLEN];
	char event[64];
	struct strlist *namelist;

	fd = open_kprobe_events(O_RDWR, O_APPEND);
	/* Get current event names */
	namelist = get_perf_event_names(fd, false);

	for (j = 0; j < nr_probes; j++) {
		pp = probes + j;
		for (i = 0; i < pp->found; i++) {
			/* Get an unused new event name */
			get_new_event_name(event, 64, pp->function, namelist);
			snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
				 pp->retprobe ? 'r' : 'p',
				 PERFPROBE_GROUP, event,
				 pp->probes[i]);
			write_trace_kprobe_event(fd, buf);
			printf("Added new event:\n");
			/* Get the first parameter (probe-point) */
			sscanf(pp->probes[i], "%s", buf);
			show_perf_probe_event(PERFPROBE_GROUP, event,
					      buf, pp);
			/* Add added event name to namelist */
			strlist__add(namelist, event);
		}
	}
	/* Show how to use the event. */
	printf("\nYou can now use it on all perf tools, such as:\n\n");
	printf("\tperf record -e %s:%s -a sleep 1\n\n", PERFPROBE_GROUP, event);

	strlist__delete(namelist);
	close(fd);
}

static void del_trace_kprobe_event(int fd, const char *group,
				   const char *event, struct strlist *namelist)
{
	char buf[128];

	if (e_snprintf(buf, 128, "%s:%s", group, event) < 0)
		die("Failed to copy event.");
	if (!strlist__has_entry(namelist, buf)) {
		pr_warning("Warning: event \"%s\" is not found.\n", buf);
		return;
	}
	/* Convert from perf-probe event to trace-kprobe event */
	if (e_snprintf(buf, 128, "-:%s/%s", group, event) < 0)
		die("Failed to copy event.");

	write_trace_kprobe_event(fd, buf);
	printf("Remove event: %s:%s\n", group, event);
}

void del_trace_kprobe_events(struct strlist *dellist)
{
	int fd;
	unsigned int i;
	const char *group, *event;
	char *p, *str;
	struct str_node *ent;
	struct strlist *namelist;

	fd = open_kprobe_events(O_RDWR, O_APPEND);
	/* Get current event names */
	namelist = get_perf_event_names(fd, true);

	for (i = 0; i < strlist__nr_entries(dellist); i++) {
		ent = strlist__entry(dellist, i);
		str = strdup(ent->s);
		if (!str)
			die("Failed to copy event.");
		p = strchr(str, ':');
		if (p) {
			group = str;
			*p = '\0';
			event = p + 1;
		} else {
			group = PERFPROBE_GROUP;
			event = str;
		}
		del_trace_kprobe_event(fd, group, event, namelist);
		free(str);
	}
	strlist__delete(namelist);
	close(fd);
}