summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/probe-file.c
blob: 436b64731f65112f3c624a70a077f7370532da5a (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
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
/*
 * probe-file.c : operate ftrace k/uprobe events files
 *
 * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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.
 *
 */
#include <sys/uio.h>
#include "util.h"
#include "event.h"
#include "strlist.h"
#include "debug.h"
#include "cache.h"
#include "color.h"
#include "symbol.h"
#include "thread.h"
#include <api/fs/tracing_path.h>
#include "probe-event.h"
#include "probe-file.h"
#include "session.h"

#define MAX_CMDLEN 256

static void print_open_warning(int err, bool uprobe)
{
	char sbuf[STRERR_BUFSIZE];

	if (err == -ENOENT) {
		const char *config;

		if (uprobe)
			config = "CONFIG_UPROBE_EVENTS";
		else
			config = "CONFIG_KPROBE_EVENTS";

		pr_warning("%cprobe_events file does not exist"
			   " - please rebuild kernel with %s.\n",
			   uprobe ? 'u' : 'k', config);
	} else if (err == -ENOTSUP)
		pr_warning("Tracefs or debugfs is not mounted.\n");
	else
		pr_warning("Failed to open %cprobe_events: %s\n",
			   uprobe ? 'u' : 'k',
			   str_error_r(-err, sbuf, sizeof(sbuf)));
}

static void print_both_open_warning(int kerr, int uerr)
{
	/* Both kprobes and uprobes are disabled, warn it. */
	if (kerr == -ENOTSUP && uerr == -ENOTSUP)
		pr_warning("Tracefs or debugfs is not mounted.\n");
	else if (kerr == -ENOENT && uerr == -ENOENT)
		pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
			   "or/and CONFIG_UPROBE_EVENTS.\n");
	else {
		char sbuf[STRERR_BUFSIZE];
		pr_warning("Failed to open kprobe events: %s.\n",
			   str_error_r(-kerr, sbuf, sizeof(sbuf)));
		pr_warning("Failed to open uprobe events: %s.\n",
			   str_error_r(-uerr, sbuf, sizeof(sbuf)));
	}
}

static int open_probe_events(const char *trace_file, bool readwrite)
{
	char buf[PATH_MAX];
	int ret;

	ret = e_snprintf(buf, PATH_MAX, "%s/%s",
			 tracing_path, trace_file);
	if (ret >= 0) {
		pr_debug("Opening %s write=%d\n", buf, readwrite);
		if (readwrite && !probe_event_dry_run)
			ret = open(buf, O_RDWR | O_APPEND, 0);
		else
			ret = open(buf, O_RDONLY, 0);

		if (ret < 0)
			ret = -errno;
	}
	return ret;
}

static int open_kprobe_events(bool readwrite)
{
	return open_probe_events("kprobe_events", readwrite);
}

static int open_uprobe_events(bool readwrite)
{
	return open_probe_events("uprobe_events", readwrite);
}

int probe_file__open(int flag)
{
	int fd;

	if (flag & PF_FL_UPROBE)
		fd = open_uprobe_events(flag & PF_FL_RW);
	else
		fd = open_kprobe_events(flag & PF_FL_RW);
	if (fd < 0)
		print_open_warning(fd, flag & PF_FL_UPROBE);

	return fd;
}

int probe_file__open_both(int *kfd, int *ufd, int flag)
{
	if (!kfd || !ufd)
		return -EINVAL;

	*kfd = open_kprobe_events(flag & PF_FL_RW);
	*ufd = open_uprobe_events(flag & PF_FL_RW);
	if (*kfd < 0 && *ufd < 0) {
		print_both_open_warning(*kfd, *ufd);
		return *kfd;
	}

	return 0;
}

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

	if (fd < 0)
		return NULL;

	sl = strlist__new(NULL, NULL);
	if (sl == NULL)
		return NULL;

	fddup = dup(fd);
	if (fddup < 0)
		goto out_free_sl;

	fp = fdopen(fddup, "r");
	if (!fp)
		goto out_close_fddup;

	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) {
			pr_debug("strlist__add failed (%d)\n", ret);
			goto out_close_fp;
		}
	}
	fclose(fp);

	return sl;

out_close_fp:
	fclose(fp);
	goto out_free_sl;
out_close_fddup:
	close(fddup);
out_free_sl:
	strlist__delete(sl);
	return NULL;
}

static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
{
	char buf[128];
	struct strlist *sl, *rawlist;
	struct str_node *ent;
	struct probe_trace_event tev;
	int ret = 0;

	memset(&tev, 0, sizeof(tev));
	rawlist = probe_file__get_rawlist(fd);
	if (!rawlist)
		return NULL;
	sl = strlist__new(NULL, NULL);
	strlist__for_each_entry(ent, rawlist) {
		ret = parse_probe_trace_command(ent->s, &tev);
		if (ret < 0)
			break;
		if (include_group) {
			ret = e_snprintf(buf, 128, "%s:%s", tev.group,
					tev.event);
			if (ret >= 0)
				ret = strlist__add(sl, buf);
		} else
			ret = strlist__add(sl, tev.event);
		clear_probe_trace_event(&tev);
		if (ret < 0)
			break;
	}
	strlist__delete(rawlist);

	if (ret < 0) {
		strlist__delete(sl);
		return NULL;
	}
	return sl;
}

/* Get current perf-probe event names */
struct strlist *probe_file__get_namelist(int fd)
{
	return __probe_file__get_namelist(fd, false);
}

int probe_file__add_event(int fd, struct probe_trace_event *tev)
{
	int ret = 0;
	char *buf = synthesize_probe_trace_command(tev);
	char sbuf[STRERR_BUFSIZE];

	if (!buf) {
		pr_debug("Failed to synthesize probe trace event.\n");
		return -EINVAL;
	}

	pr_debug("Writing event: %s\n", buf);
	if (!probe_event_dry_run) {
		if (write(fd, buf, strlen(buf)) < (int)strlen(buf)) {
			ret = -errno;
			pr_warning("Failed to write event: %s\n",
				   str_error_r(errno, sbuf, sizeof(sbuf)));
		}
	}
	free(buf);

	return ret;
}

static int __del_trace_probe_event(int fd, struct str_node *ent)
{
	char *p;
	char buf[128];
	int ret;

	/* Convert from perf-probe event to trace-probe event */
	ret = e_snprintf(buf, 128, "-:%s", ent->s);
	if (ret < 0)
		goto error;

	p = strchr(buf + 2, ':');
	if (!p) {
		pr_debug("Internal error: %s should have ':' but not.\n",
			 ent->s);
		ret = -ENOTSUP;
		goto error;
	}
	*p = '/';

	pr_debug("Writing event: %s\n", buf);
	ret = write(fd, buf, strlen(buf));
	if (ret < 0) {
		ret = -errno;
		goto error;
	}

	return 0;
error:
	pr_warning("Failed to delete event: %s\n",
		   str_error_r(-ret, buf, sizeof(buf)));
	return ret;
}

int probe_file__get_events(int fd, struct strfilter *filter,
			   struct strlist *plist)
{
	struct strlist *namelist;
	struct str_node *ent;
	const char *p;
	int ret = -ENOENT;

	if (!plist)
		return -EINVAL;

	namelist = __probe_file__get_namelist(fd, true);
	if (!namelist)
		return -ENOENT;

	strlist__for_each_entry(ent, namelist) {
		p = strchr(ent->s, ':');
		if ((p && strfilter__compare(filter, p + 1)) ||
		    strfilter__compare(filter, ent->s)) {
			strlist__add(plist, ent->s);
			ret = 0;
		}
	}
	strlist__delete(namelist);

	return ret;
}

int probe_file__del_strlist(int fd, struct strlist *namelist)
{
	int ret = 0;
	struct str_node *ent;

	strlist__for_each_entry(ent, namelist) {
		ret = __del_trace_probe_event(fd, ent);
		if (ret < 0)
			break;
	}
	return ret;
}

int probe_file__del_events(int fd, struct strfilter *filter)
{
	struct strlist *namelist;
	int ret;

	namelist = strlist__new(NULL, NULL);
	if (!namelist)
		return -ENOMEM;

	ret = probe_file__get_events(fd, filter, namelist);
	if (ret < 0)
		return ret;

	ret = probe_file__del_strlist(fd, namelist);
	strlist__delete(namelist);

	return ret;
}

/* Caller must ensure to remove this entry from list */
static void probe_cache_entry__delete(struct probe_cache_entry *entry)
{
	if (entry) {
		BUG_ON(!list_empty(&entry->node));

		strlist__delete(entry->tevlist);
		clear_perf_probe_event(&entry->pev);
		zfree(&entry->spev);
		free(entry);
	}
}

static struct probe_cache_entry *
probe_cache_entry__new(struct perf_probe_event *pev)
{
	struct probe_cache_entry *entry = zalloc(sizeof(*entry));

	if (entry) {
		INIT_LIST_HEAD(&entry->node);
		entry->tevlist = strlist__new(NULL, NULL);
		if (!entry->tevlist)
			zfree(&entry);
		else if (pev) {
			entry->spev = synthesize_perf_probe_command(pev);
			if (!entry->spev ||
			    perf_probe_event__copy(&entry->pev, pev) < 0) {
				probe_cache_entry__delete(entry);
				return NULL;
			}
		}
	}

	return entry;
}

int probe_cache_entry__get_event(struct probe_cache_entry *entry,
				 struct probe_trace_event **tevs)
{
	struct probe_trace_event *tev;
	struct str_node *node;
	int ret, i;

	ret = strlist__nr_entries(entry->tevlist);
	if (ret > probe_conf.max_probes)
		return -E2BIG;

	*tevs = zalloc(ret * sizeof(*tev));
	if (!*tevs)
		return -ENOMEM;

	i = 0;
	strlist__for_each_entry(node, entry->tevlist) {
		tev = &(*tevs)[i++];
		ret = parse_probe_trace_command(node->s, tev);
		if (ret < 0)
			break;
	}
	return i;
}

/* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
static int probe_cache__open(struct probe_cache *pcache, const char *target)
{
	char cpath[PATH_MAX];
	char sbuildid[SBUILD_ID_SIZE];
	char *dir_name = NULL;
	bool is_kallsyms = false;
	int ret, fd;

	if (target && build_id_cache__cached(target)) {
		/* This is a cached buildid */
		strncpy(sbuildid, target, SBUILD_ID_SIZE);
		dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
		goto found;
	}

	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
		target = DSO__NAME_KALLSYMS;
		is_kallsyms = true;
		ret = sysfs__sprintf_build_id("/", sbuildid);
	} else
		ret = filename__sprintf_build_id(target, sbuildid);

	if (ret < 0) {
		pr_debug("Failed to get build-id from %s.\n", target);
		return ret;
	}

	/* If we have no buildid cache, make it */
	if (!build_id_cache__cached(sbuildid)) {
		ret = build_id_cache__add_s(sbuildid, target,
					    is_kallsyms, NULL);
		if (ret < 0) {
			pr_debug("Failed to add build-id cache: %s\n", target);
			return ret;
		}
	}

	dir_name = build_id_cache__cachedir(sbuildid, target, is_kallsyms,
					    false);
found:
	if (!dir_name) {
		pr_debug("Failed to get cache from %s\n", target);
		return -ENOMEM;
	}

	snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
	fd = open(cpath, O_CREAT | O_RDWR, 0644);
	if (fd < 0)
		pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
	free(dir_name);
	pcache->fd = fd;

	return fd;
}

static int probe_cache__load(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry = NULL;
	char buf[MAX_CMDLEN], *p;
	int ret = 0, fddup;
	FILE *fp;

	fddup = dup(pcache->fd);
	if (fddup < 0)
		return -errno;
	fp = fdopen(fddup, "r");
	if (!fp) {
		close(fddup);
		return -EINVAL;
	}

	while (!feof(fp)) {
		if (!fgets(buf, MAX_CMDLEN, fp))
			break;
		p = strchr(buf, '\n');
		if (p)
			*p = '\0';
		/* #perf_probe_event or %sdt_event */
		if (buf[0] == '#' || buf[0] == '%') {
			entry = probe_cache_entry__new(NULL);
			if (!entry) {
				ret = -ENOMEM;
				goto out;
			}
			if (buf[0] == '%')
				entry->sdt = true;
			entry->spev = strdup(buf + 1);
			if (entry->spev)
				ret = parse_perf_probe_command(buf + 1,
								&entry->pev);
			else
				ret = -ENOMEM;
			if (ret < 0) {
				probe_cache_entry__delete(entry);
				goto out;
			}
			list_add_tail(&entry->node, &pcache->entries);
		} else {	/* trace_probe_event */
			if (!entry) {
				ret = -EINVAL;
				goto out;
			}
			strlist__add(entry->tevlist, buf);
		}
	}
out:
	fclose(fp);
	return ret;
}

static struct probe_cache *probe_cache__alloc(void)
{
	struct probe_cache *pcache = zalloc(sizeof(*pcache));

	if (pcache) {
		INIT_LIST_HEAD(&pcache->entries);
		pcache->fd = -EINVAL;
	}
	return pcache;
}

void probe_cache__purge(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry, *n;

	list_for_each_entry_safe(entry, n, &pcache->entries, node) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}
}

void probe_cache__delete(struct probe_cache *pcache)
{
	if (!pcache)
		return;

	probe_cache__purge(pcache);
	if (pcache->fd > 0)
		close(pcache->fd);
	free(pcache);
}

struct probe_cache *probe_cache__new(const char *target)
{
	struct probe_cache *pcache = probe_cache__alloc();
	int ret;

	if (!pcache)
		return NULL;

	ret = probe_cache__open(pcache, target);
	if (ret < 0) {
		pr_debug("Cache open error: %d\n", ret);
		goto out_err;
	}

	ret = probe_cache__load(pcache);
	if (ret < 0) {
		pr_debug("Cache read error: %d\n", ret);
		goto out_err;
	}

	return pcache;

out_err:
	probe_cache__delete(pcache);
	return NULL;
}

static bool streql(const char *a, const char *b)
{
	if (a == b)
		return true;

	if (!a || !b)
		return false;

	return !strcmp(a, b);
}

struct probe_cache_entry *
probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
{
	struct probe_cache_entry *entry = NULL;
	char *cmd = synthesize_perf_probe_command(pev);

	if (!cmd)
		return NULL;

	for_each_probe_cache_entry(entry, pcache) {
		if (pev->sdt) {
			if (entry->pev.event &&
			    streql(entry->pev.event, pev->event) &&
			    (!pev->group ||
			     streql(entry->pev.group, pev->group)))
				goto found;

			continue;
		}
		/* Hit if same event name or same command-string */
		if ((pev->event &&
		     (streql(entry->pev.group, pev->group) &&
		      streql(entry->pev.event, pev->event))) ||
		    (!strcmp(entry->spev, cmd)))
			goto found;
	}
	entry = NULL;

found:
	free(cmd);
	return entry;
}

struct probe_cache_entry *
probe_cache__find_by_name(struct probe_cache *pcache,
			  const char *group, const char *event)
{
	struct probe_cache_entry *entry = NULL;

	for_each_probe_cache_entry(entry, pcache) {
		/* Hit if same event name or same command-string */
		if (streql(entry->pev.group, group) &&
		    streql(entry->pev.event, event))
			goto found;
	}
	entry = NULL;

found:
	return entry;
}

int probe_cache__add_entry(struct probe_cache *pcache,
			   struct perf_probe_event *pev,
			   struct probe_trace_event *tevs, int ntevs)
{
	struct probe_cache_entry *entry = NULL;
	char *command;
	int i, ret = 0;

	if (!pcache || !pev || !tevs || ntevs <= 0) {
		ret = -EINVAL;
		goto out_err;
	}

	/* Remove old cache entry */
	entry = probe_cache__find(pcache, pev);
	if (entry) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}

	ret = -ENOMEM;
	entry = probe_cache_entry__new(pev);
	if (!entry)
		goto out_err;

	for (i = 0; i < ntevs; i++) {
		if (!tevs[i].point.symbol)
			continue;

		command = synthesize_probe_trace_command(&tevs[i]);
		if (!command)
			goto out_err;
		strlist__add(entry->tevlist, command);
		free(command);
	}
	list_add_tail(&entry->node, &pcache->entries);
	pr_debug("Added probe cache: %d\n", ntevs);
	return 0;

out_err:
	pr_debug("Failed to add probe caches\n");
	probe_cache_entry__delete(entry);
	return ret;
}

#ifdef HAVE_GELF_GETNOTE_SUPPORT
static unsigned long long sdt_note__get_addr(struct sdt_note *note)
{
	return note->bit32 ? (unsigned long long)note->addr.a32[0]
		 : (unsigned long long)note->addr.a64[0];
}

int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname)
{
	struct probe_cache_entry *entry = NULL;
	struct list_head sdtlist;
	struct sdt_note *note;
	char *buf;
	char sdtgrp[64];
	int ret;

	INIT_LIST_HEAD(&sdtlist);
	ret = get_sdt_note_list(&sdtlist, pathname);
	if (ret < 0) {
		pr_debug4("Failed to get sdt note: %d\n", ret);
		return ret;
	}
	list_for_each_entry(note, &sdtlist, note_list) {
		ret = snprintf(sdtgrp, 64, "sdt_%s", note->provider);
		if (ret < 0)
			break;
		/* Try to find same-name entry */
		entry = probe_cache__find_by_name(pcache, sdtgrp, note->name);
		if (!entry) {
			entry = probe_cache_entry__new(NULL);
			if (!entry) {
				ret = -ENOMEM;
				break;
			}
			entry->sdt = true;
			ret = asprintf(&entry->spev, "%s:%s=%s", sdtgrp,
					note->name, note->name);
			if (ret < 0)
				break;
			entry->pev.event = strdup(note->name);
			entry->pev.group = strdup(sdtgrp);
			list_add_tail(&entry->node, &pcache->entries);
		}
		ret = asprintf(&buf, "p:%s/%s %s:0x%llx",
				sdtgrp, note->name, pathname,
				sdt_note__get_addr(note));
		if (ret < 0)
			break;
		strlist__add(entry->tevlist, buf);
		free(buf);
		entry = NULL;
	}
	if (entry) {
		list_del_init(&entry->node);
		probe_cache_entry__delete(entry);
	}
	cleanup_sdt_note_list(&sdtlist);
	return ret;
}
#endif

static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
{
	struct str_node *snode;
	struct stat st;
	struct iovec iov[3];
	const char *prefix = entry->sdt ? "%" : "#";
	int ret;
	/* Save stat for rollback */
	ret = fstat(fd, &st);
	if (ret < 0)
		return ret;

	pr_debug("Writing cache: %s%s\n", prefix, entry->spev);
	iov[0].iov_base = (void *)prefix; iov[0].iov_len = 1;
	iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
	iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
	ret = writev(fd, iov, 3);
	if (ret < (int)iov[1].iov_len + 2)
		goto rollback;

	strlist__for_each_entry(snode, entry->tevlist) {
		iov[0].iov_base = (void *)snode->s;
		iov[0].iov_len = strlen(snode->s);
		iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
		ret = writev(fd, iov, 2);
		if (ret < (int)iov[0].iov_len + 1)
			goto rollback;
	}
	return 0;

rollback:
	/* Rollback to avoid cache file corruption */
	if (ret > 0)
		ret = -1;
	if (ftruncate(fd, st.st_size) < 0)
		ret = -2;

	return ret;
}

int probe_cache__commit(struct probe_cache *pcache)
{
	struct probe_cache_entry *entry;
	int ret = 0;

	/* TBD: if we do not update existing entries, skip it */
	ret = lseek(pcache->fd, 0, SEEK_SET);
	if (ret < 0)
		goto out;

	ret = ftruncate(pcache->fd, 0);
	if (ret < 0)
		goto out;

	for_each_probe_cache_entry(entry, pcache) {
		ret = probe_cache_entry__write(entry, pcache->fd);
		pr_debug("Cache committed: %d\n", ret);
		if (ret < 0)
			break;
	}
out:
	return ret;
}

static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
				       struct strfilter *filter)
{
	char buf[128], *ptr = entry->spev;

	if (entry->pev.event) {
		snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
		ptr = buf;
	}
	return strfilter__compare(filter, ptr);
}

int probe_cache__filter_purge(struct probe_cache *pcache,
			      struct strfilter *filter)
{
	struct probe_cache_entry *entry, *tmp;

	list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
		if (probe_cache_entry__compare(entry, filter)) {
			pr_info("Removed cached event: %s\n", entry->spev);
			list_del_init(&entry->node);
			probe_cache_entry__delete(entry);
		}
	}
	return 0;
}

static int probe_cache__show_entries(struct probe_cache *pcache,
				     struct strfilter *filter)
{
	struct probe_cache_entry *entry;

	for_each_probe_cache_entry(entry, pcache) {
		if (probe_cache_entry__compare(entry, filter))
			printf("%s\n", entry->spev);
	}
	return 0;
}

/* Show all cached probes */
int probe_cache__show_all_caches(struct strfilter *filter)
{
	struct probe_cache *pcache;
	struct strlist *bidlist;
	struct str_node *nd;
	char *buf = strfilter__string(filter);

	pr_debug("list cache with filter: %s\n", buf);
	free(buf);

	bidlist = build_id_cache__list_all(true);
	if (!bidlist) {
		pr_debug("Failed to get buildids: %d\n", errno);
		return -EINVAL;
	}
	strlist__for_each_entry(nd, bidlist) {
		pcache = probe_cache__new(nd->s);
		if (!pcache)
			continue;
		if (!list_empty(&pcache->entries)) {
			buf = build_id_cache__origname(nd->s);
			printf("%s (%s):\n", buf, nd->s);
			free(buf);
			probe_cache__show_entries(pcache, filter);
		}
		probe_cache__delete(pcache);
	}
	strlist__delete(bidlist);

	return 0;
}

static struct {
	const char *pattern;
	bool	avail;
	bool	checked;
} probe_type_table[] = {
#define DEFINE_TYPE(idx, pat, def_avail)	\
	[idx] = {.pattern = pat, .avail = (def_avail)}
	DEFINE_TYPE(PROBE_TYPE_U, "* u8/16/32/64,*", true),
	DEFINE_TYPE(PROBE_TYPE_S, "* s8/16/32/64,*", true),
	DEFINE_TYPE(PROBE_TYPE_X, "* x8/16/32/64,*", false),
	DEFINE_TYPE(PROBE_TYPE_STRING, "* string,*", true),
	DEFINE_TYPE(PROBE_TYPE_BITFIELD,
		    "* b<bit-width>@<bit-offset>/<container-size>", true),
};

bool probe_type_is_available(enum probe_type type)
{
	FILE *fp;
	char *buf = NULL;
	size_t len = 0;
	bool target_line = false;
	bool ret = probe_type_table[type].avail;

	if (type >= PROBE_TYPE_END)
		return false;
	/* We don't have to check the type which supported by default */
	if (ret || probe_type_table[type].checked)
		return ret;

	if (asprintf(&buf, "%s/README", tracing_path) < 0)
		return ret;

	fp = fopen(buf, "r");
	if (!fp)
		goto end;

	zfree(&buf);
	while (getline(&buf, &len, fp) > 0 && !ret) {
		if (!target_line) {
			target_line = !!strstr(buf, " type: ");
			if (!target_line)
				continue;
		} else if (strstr(buf, "\t          ") != buf)
			break;
		ret = strglobmatch(buf, probe_type_table[type].pattern);
	}
	/* Cache the result */
	probe_type_table[type].checked = true;
	probe_type_table[type].avail = ret;

	fclose(fp);
end:
	free(buf);

	return ret;
}