xref: /linux/tools/perf/util/trace-event-info.c (revision bfd5bb6f90af092aa345b15cd78143956a13c2a8)
1 /*
2  * Copyright (C) 2008,2009, Steven Rostedt <srostedt@redhat.com>
3  *
4  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; version 2 of the License (not later!)
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  *
19  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20  */
21 #include "util.h"
22 #include <dirent.h>
23 #include <mntent.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <stdarg.h>
28 #include <sys/types.h>
29 #include <sys/stat.h>
30 #include <sys/wait.h>
31 #include <fcntl.h>
32 #include <unistd.h>
33 #include <errno.h>
34 #include <stdbool.h>
35 #include <linux/list.h>
36 #include <linux/kernel.h>
37 
38 #include "../perf.h"
39 #include "trace-event.h"
40 #include <api/fs/tracing_path.h>
41 #include "evsel.h"
42 #include "debug.h"
43 
44 #define VERSION "0.6"
45 
46 static int output_fd;
47 
48 
49 int bigendian(void)
50 {
51 	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0};
52 	unsigned int *ptr;
53 
54 	ptr = (unsigned int *)(void *)str;
55 	return *ptr == 0x01020304;
56 }
57 
58 /* unfortunately, you can not stat debugfs or proc files for size */
59 static int record_file(const char *file, ssize_t hdr_sz)
60 {
61 	unsigned long long size = 0;
62 	char buf[BUFSIZ], *sizep;
63 	off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
64 	int r, fd;
65 	int err = -EIO;
66 
67 	fd = open(file, O_RDONLY);
68 	if (fd < 0) {
69 		pr_debug("Can't read '%s'", file);
70 		return -errno;
71 	}
72 
73 	/* put in zeros for file size, then fill true size later */
74 	if (hdr_sz) {
75 		if (write(output_fd, &size, hdr_sz) != hdr_sz)
76 			goto out;
77 	}
78 
79 	do {
80 		r = read(fd, buf, BUFSIZ);
81 		if (r > 0) {
82 			size += r;
83 			if (write(output_fd, buf, r) != r)
84 				goto out;
85 		}
86 	} while (r > 0);
87 
88 	/* ugh, handle big-endian hdr_size == 4 */
89 	sizep = (char*)&size;
90 	if (bigendian())
91 		sizep += sizeof(u64) - hdr_sz;
92 
93 	if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0) {
94 		pr_debug("writing file size failed\n");
95 		goto out;
96 	}
97 
98 	err = 0;
99 out:
100 	close(fd);
101 	return err;
102 }
103 
104 static int record_header_files(void)
105 {
106 	char *path = get_events_file("header_page");
107 	struct stat st;
108 	int err = -EIO;
109 
110 	if (!path) {
111 		pr_debug("can't get tracing/events/header_page");
112 		return -ENOMEM;
113 	}
114 
115 	if (stat(path, &st) < 0) {
116 		pr_debug("can't read '%s'", path);
117 		goto out;
118 	}
119 
120 	if (write(output_fd, "header_page", 12) != 12) {
121 		pr_debug("can't write header_page\n");
122 		goto out;
123 	}
124 
125 	if (record_file(path, 8) < 0) {
126 		pr_debug("can't record header_page file\n");
127 		goto out;
128 	}
129 
130 	put_events_file(path);
131 
132 	path = get_events_file("header_event");
133 	if (!path) {
134 		pr_debug("can't get tracing/events/header_event");
135 		err = -ENOMEM;
136 		goto out;
137 	}
138 
139 	if (stat(path, &st) < 0) {
140 		pr_debug("can't read '%s'", path);
141 		goto out;
142 	}
143 
144 	if (write(output_fd, "header_event", 13) != 13) {
145 		pr_debug("can't write header_event\n");
146 		goto out;
147 	}
148 
149 	if (record_file(path, 8) < 0) {
150 		pr_debug("can't record header_event file\n");
151 		goto out;
152 	}
153 
154 	err = 0;
155 out:
156 	put_events_file(path);
157 	return err;
158 }
159 
160 static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
161 {
162 	while (tps) {
163 		if (!strcmp(sys, tps->name))
164 			return true;
165 		tps = tps->next;
166 	}
167 
168 	return false;
169 }
170 
171 #define for_each_event(dir, dent, tps)				\
172 	while ((dent = readdir(dir)))				\
173 		if (dent->d_type == DT_DIR &&			\
174 		    (strcmp(dent->d_name, ".")) &&		\
175 		    (strcmp(dent->d_name, "..")))		\
176 
177 static int copy_event_system(const char *sys, struct tracepoint_path *tps)
178 {
179 	struct dirent *dent;
180 	struct stat st;
181 	char *format;
182 	DIR *dir;
183 	int count = 0;
184 	int ret;
185 	int err;
186 
187 	dir = opendir(sys);
188 	if (!dir) {
189 		pr_debug("can't read directory '%s'", sys);
190 		return -errno;
191 	}
192 
193 	for_each_event(dir, dent, tps) {
194 		if (!name_in_tp_list(dent->d_name, tps))
195 			continue;
196 
197 		if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
198 			err = -ENOMEM;
199 			goto out;
200 		}
201 		ret = stat(format, &st);
202 		free(format);
203 		if (ret < 0)
204 			continue;
205 		count++;
206 	}
207 
208 	if (write(output_fd, &count, 4) != 4) {
209 		err = -EIO;
210 		pr_debug("can't write count\n");
211 		goto out;
212 	}
213 
214 	rewinddir(dir);
215 	for_each_event(dir, dent, tps) {
216 		if (!name_in_tp_list(dent->d_name, tps))
217 			continue;
218 
219 		if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
220 			err = -ENOMEM;
221 			goto out;
222 		}
223 		ret = stat(format, &st);
224 
225 		if (ret >= 0) {
226 			err = record_file(format, 8);
227 			if (err) {
228 				free(format);
229 				goto out;
230 			}
231 		}
232 		free(format);
233 	}
234 	err = 0;
235 out:
236 	closedir(dir);
237 	return err;
238 }
239 
240 static int record_ftrace_files(struct tracepoint_path *tps)
241 {
242 	char *path;
243 	int ret;
244 
245 	path = get_events_file("ftrace");
246 	if (!path) {
247 		pr_debug("can't get tracing/events/ftrace");
248 		return -ENOMEM;
249 	}
250 
251 	ret = copy_event_system(path, tps);
252 
253 	put_tracing_file(path);
254 
255 	return ret;
256 }
257 
258 static bool system_in_tp_list(char *sys, struct tracepoint_path *tps)
259 {
260 	while (tps) {
261 		if (!strcmp(sys, tps->system))
262 			return true;
263 		tps = tps->next;
264 	}
265 
266 	return false;
267 }
268 
269 static int record_event_files(struct tracepoint_path *tps)
270 {
271 	struct dirent *dent;
272 	struct stat st;
273 	char *path;
274 	char *sys;
275 	DIR *dir;
276 	int count = 0;
277 	int ret;
278 	int err;
279 
280 	path = get_tracing_file("events");
281 	if (!path) {
282 		pr_debug("can't get tracing/events");
283 		return -ENOMEM;
284 	}
285 
286 	dir = opendir(path);
287 	if (!dir) {
288 		err = -errno;
289 		pr_debug("can't read directory '%s'", path);
290 		goto out;
291 	}
292 
293 	for_each_event(dir, dent, tps) {
294 		if (strcmp(dent->d_name, "ftrace") == 0 ||
295 		    !system_in_tp_list(dent->d_name, tps))
296 			continue;
297 
298 		count++;
299 	}
300 
301 	if (write(output_fd, &count, 4) != 4) {
302 		err = -EIO;
303 		pr_debug("can't write count\n");
304 		goto out;
305 	}
306 
307 	rewinddir(dir);
308 	for_each_event(dir, dent, tps) {
309 		if (strcmp(dent->d_name, "ftrace") == 0 ||
310 		    !system_in_tp_list(dent->d_name, tps))
311 			continue;
312 
313 		if (asprintf(&sys, "%s/%s", path, dent->d_name) < 0) {
314 			err = -ENOMEM;
315 			goto out;
316 		}
317 		ret = stat(sys, &st);
318 		if (ret >= 0) {
319 			ssize_t size = strlen(dent->d_name) + 1;
320 
321 			if (write(output_fd, dent->d_name, size) != size ||
322 			    copy_event_system(sys, tps) < 0) {
323 				err = -EIO;
324 				free(sys);
325 				goto out;
326 			}
327 		}
328 		free(sys);
329 	}
330 	err = 0;
331 out:
332 	closedir(dir);
333 	put_tracing_file(path);
334 
335 	return err;
336 }
337 
338 static int record_proc_kallsyms(void)
339 {
340 	unsigned long long size = 0;
341 	/*
342 	 * Just to keep older perf.data file parsers happy, record a zero
343 	 * sized kallsyms file, i.e. do the same thing that was done when
344 	 * /proc/kallsyms (or something specified via --kallsyms, in a
345 	 * different path) couldn't be read.
346 	 */
347 	return write(output_fd, &size, 4) != 4 ? -EIO : 0;
348 }
349 
350 static int record_ftrace_printk(void)
351 {
352 	unsigned int size;
353 	char *path;
354 	struct stat st;
355 	int ret, err = 0;
356 
357 	path = get_tracing_file("printk_formats");
358 	if (!path) {
359 		pr_debug("can't get tracing/printk_formats");
360 		return -ENOMEM;
361 	}
362 
363 	ret = stat(path, &st);
364 	if (ret < 0) {
365 		/* not found */
366 		size = 0;
367 		if (write(output_fd, &size, 4) != 4)
368 			err = -EIO;
369 		goto out;
370 	}
371 	err = record_file(path, 4);
372 
373 out:
374 	put_tracing_file(path);
375 	return err;
376 }
377 
378 static int record_saved_cmdline(void)
379 {
380 	unsigned int size;
381 	char *path;
382 	struct stat st;
383 	int ret, err = 0;
384 
385 	path = get_tracing_file("saved_cmdlines");
386 	if (!path) {
387 		pr_debug("can't get tracing/saved_cmdline");
388 		return -ENOMEM;
389 	}
390 
391 	ret = stat(path, &st);
392 	if (ret < 0) {
393 		/* not found */
394 		size = 0;
395 		if (write(output_fd, &size, 8) != 8)
396 			err = -EIO;
397 		goto out;
398 	}
399 	err = record_file(path, 8);
400 
401 out:
402 	put_tracing_file(path);
403 	return err;
404 }
405 
406 static void
407 put_tracepoints_path(struct tracepoint_path *tps)
408 {
409 	while (tps) {
410 		struct tracepoint_path *t = tps;
411 
412 		tps = tps->next;
413 		zfree(&t->name);
414 		zfree(&t->system);
415 		free(t);
416 	}
417 }
418 
419 static struct tracepoint_path *
420 get_tracepoints_path(struct list_head *pattrs)
421 {
422 	struct tracepoint_path path, *ppath = &path;
423 	struct perf_evsel *pos;
424 	int nr_tracepoints = 0;
425 
426 	list_for_each_entry(pos, pattrs, node) {
427 		if (pos->attr.type != PERF_TYPE_TRACEPOINT)
428 			continue;
429 		++nr_tracepoints;
430 
431 		if (pos->name) {
432 			ppath->next = tracepoint_name_to_path(pos->name);
433 			if (ppath->next)
434 				goto next;
435 
436 			if (strchr(pos->name, ':') == NULL)
437 				goto try_id;
438 
439 			goto error;
440 		}
441 
442 try_id:
443 		ppath->next = tracepoint_id_to_path(pos->attr.config);
444 		if (!ppath->next) {
445 error:
446 			pr_debug("No memory to alloc tracepoints list\n");
447 			put_tracepoints_path(&path);
448 			return NULL;
449 		}
450 next:
451 		ppath = ppath->next;
452 	}
453 
454 	return nr_tracepoints > 0 ? path.next : NULL;
455 }
456 
457 bool have_tracepoints(struct list_head *pattrs)
458 {
459 	struct perf_evsel *pos;
460 
461 	list_for_each_entry(pos, pattrs, node)
462 		if (pos->attr.type == PERF_TYPE_TRACEPOINT)
463 			return true;
464 
465 	return false;
466 }
467 
468 static int tracing_data_header(void)
469 {
470 	char buf[20];
471 	ssize_t size;
472 
473 	/* just guessing this is someone's birthday.. ;) */
474 	buf[0] = 23;
475 	buf[1] = 8;
476 	buf[2] = 68;
477 	memcpy(buf + 3, "tracing", 7);
478 
479 	if (write(output_fd, buf, 10) != 10)
480 		return -1;
481 
482 	size = strlen(VERSION) + 1;
483 	if (write(output_fd, VERSION, size) != size)
484 		return -1;
485 
486 	/* save endian */
487 	if (bigendian())
488 		buf[0] = 1;
489 	else
490 		buf[0] = 0;
491 
492 	if (write(output_fd, buf, 1) != 1)
493 		return -1;
494 
495 	/* save size of long */
496 	buf[0] = sizeof(long);
497 	if (write(output_fd, buf, 1) != 1)
498 		return -1;
499 
500 	/* save page_size */
501 	if (write(output_fd, &page_size, 4) != 4)
502 		return -1;
503 
504 	return 0;
505 }
506 
507 struct tracing_data *tracing_data_get(struct list_head *pattrs,
508 				      int fd, bool temp)
509 {
510 	struct tracepoint_path *tps;
511 	struct tracing_data *tdata;
512 	int err;
513 
514 	output_fd = fd;
515 
516 	tps = get_tracepoints_path(pattrs);
517 	if (!tps)
518 		return NULL;
519 
520 	tdata = malloc(sizeof(*tdata));
521 	if (!tdata)
522 		return NULL;
523 
524 	tdata->temp = temp;
525 	tdata->size = 0;
526 
527 	if (temp) {
528 		int temp_fd;
529 
530 		snprintf(tdata->temp_file, sizeof(tdata->temp_file),
531 			 "/tmp/perf-XXXXXX");
532 		if (!mkstemp(tdata->temp_file)) {
533 			pr_debug("Can't make temp file");
534 			return NULL;
535 		}
536 
537 		temp_fd = open(tdata->temp_file, O_RDWR);
538 		if (temp_fd < 0) {
539 			pr_debug("Can't read '%s'", tdata->temp_file);
540 			return NULL;
541 		}
542 
543 		/*
544 		 * Set the temp file the default output, so all the
545 		 * tracing data are stored into it.
546 		 */
547 		output_fd = temp_fd;
548 	}
549 
550 	err = tracing_data_header();
551 	if (err)
552 		goto out;
553 	err = record_header_files();
554 	if (err)
555 		goto out;
556 	err = record_ftrace_files(tps);
557 	if (err)
558 		goto out;
559 	err = record_event_files(tps);
560 	if (err)
561 		goto out;
562 	err = record_proc_kallsyms();
563 	if (err)
564 		goto out;
565 	err = record_ftrace_printk();
566 	if (err)
567 		goto out;
568 	err = record_saved_cmdline();
569 
570 out:
571 	/*
572 	 * All tracing data are stored by now, we can restore
573 	 * the default output file in case we used temp file.
574 	 */
575 	if (temp) {
576 		tdata->size = lseek(output_fd, 0, SEEK_CUR);
577 		close(output_fd);
578 		output_fd = fd;
579 	}
580 
581 	if (err)
582 		zfree(&tdata);
583 
584 	put_tracepoints_path(tps);
585 	return tdata;
586 }
587 
588 int tracing_data_put(struct tracing_data *tdata)
589 {
590 	int err = 0;
591 
592 	if (tdata->temp) {
593 		err = record_file(tdata->temp_file, 0);
594 		unlink(tdata->temp_file);
595 	}
596 
597 	free(tdata);
598 	return err;
599 }
600 
601 int read_tracing_data(int fd, struct list_head *pattrs)
602 {
603 	int err;
604 	struct tracing_data *tdata;
605 
606 	/*
607 	 * We work over the real file, so we can write data
608 	 * directly, no temp file is needed.
609 	 */
610 	tdata = tracing_data_get(pattrs, fd, false);
611 	if (!tdata)
612 		return -ENOMEM;
613 
614 	err = tracing_data_put(tdata);
615 	return err;
616 }
617