tools/perf/util/probe-file.c

   1 /*
   2  * probe-file.c : operate ftrace k/uprobe events files
   3  *
   4  * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   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; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17 #include <sys/uio.h>
  18 #include "util.h"
  19 #include "event.h"
  20 #include "strlist.h"
  21 #include "debug.h"
  22 #include "cache.h"
  23 #include "color.h"
  24 #include "symbol.h"
  25 #include "thread.h"
  26 #include <api/fs/tracing_path.h>
  27 #include "probe-event.h"
  28 #include "probe-file.h"
  29 #include "session.h"
  30
  31 #define MAX_CMDLEN 256
  32
  33 static void print_open_warning(int err, bool uprobe)
  34 {
  35         char sbuf[STRERR_BUFSIZE];
  36
  37         if (err == -ENOENT) {
  38                 const char *config;
  39
  40                 if (uprobe)
  41                         config = "CONFIG_UPROBE_EVENTS";
  42                 else
  43                         config = "CONFIG_KPROBE_EVENTS";
  44
  45                 pr_warning("%cprobe_events file does not exist"
  46                            " - please rebuild kernel with %s.\n",
  47                            uprobe ? 'u' : 'k', config);
  48         } else if (err == -ENOTSUP)
  49                 pr_warning("Tracefs or debugfs is not mounted.\n");
  50         else
  51                 pr_warning("Failed to open %cprobe_events: %s\n",
  52                            uprobe ? 'u' : 'k',
  53                            str_error_r(-err, sbuf, sizeof(sbuf)));
  54 }
  55
  56 static void print_both_open_warning(int kerr, int uerr)
  57 {
  58         /* Both kprobes and uprobes are disabled, warn it. */
  59         if (kerr == -ENOTSUP && uerr == -ENOTSUP)
  60                 pr_warning("Tracefs or debugfs is not mounted.\n");
  61         else if (kerr == -ENOENT && uerr == -ENOENT)
  62                 pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
  63                            "or/and CONFIG_UPROBE_EVENTS.\n");
  64         else {
  65                 char sbuf[STRERR_BUFSIZE];
  66                 pr_warning("Failed to open kprobe events: %s.\n",
  67                            str_error_r(-kerr, sbuf, sizeof(sbuf)));
  68                 pr_warning("Failed to open uprobe events: %s.\n",
  69                            str_error_r(-uerr, sbuf, sizeof(sbuf)));
  70         }
  71 }
  72
  73 static int open_probe_events(const char *trace_file, bool readwrite)
  74 {
  75         char buf[PATH_MAX];
  76         const char *tracing_dir = "";
  77         int ret;
  78
  79         ret = e_snprintf(buf, PATH_MAX, "%s/%s%s",
  80                          tracing_path, tracing_dir, trace_file);
  81         if (ret >= 0) {
  82                 pr_debug("Opening %s write=%d\n", buf, readwrite);
  83                 if (readwrite && !probe_event_dry_run)
  84                         ret = open(buf, O_RDWR | O_APPEND, 0);
  85                 else
  86                         ret = open(buf, O_RDONLY, 0);
  87
  88                 if (ret < 0)
  89                         ret = -errno;
  90         }
  91         return ret;
  92 }
  93
  94 static int open_kprobe_events(bool readwrite)
  95 {
  96         return open_probe_events("kprobe_events", readwrite);
  97 }
  98
  99 static int open_uprobe_events(bool readwrite)
 100 {
 101         return open_probe_events("uprobe_events", readwrite);
 102 }
 103
 104 int probe_file__open(int flag)
 105 {
 106         int fd;
 107
 108         if (flag & PF_FL_UPROBE)
 109                 fd = open_uprobe_events(flag & PF_FL_RW);
 110         else
 111                 fd = open_kprobe_events(flag & PF_FL_RW);
 112         if (fd < 0)
 113                 print_open_warning(fd, flag & PF_FL_UPROBE);
 114
 115         return fd;
 116 }
 117
 118 int probe_file__open_both(int *kfd, int *ufd, int flag)
 119 {
 120         if (!kfd || !ufd)
 121                 return -EINVAL;
 122
 123         *kfd = open_kprobe_events(flag & PF_FL_RW);
 124         *ufd = open_uprobe_events(flag & PF_FL_RW);
 125         if (*kfd < 0 && *ufd < 0) {
 126                 print_both_open_warning(*kfd, *ufd);
 127                 return *kfd;
 128         }
 129
 130         return 0;
 131 }
 132
 133 /* Get raw string list of current kprobe_events  or uprobe_events */
 134 struct strlist *probe_file__get_rawlist(int fd)
 135 {
 136         int ret, idx;
 137         FILE *fp;
 138         char buf[MAX_CMDLEN];
 139         char *p;
 140         struct strlist *sl;
 141
 142         if (fd < 0)
 143                 return NULL;
 144
 145         sl = strlist__new(NULL, NULL);
 146
 147         fp = fdopen(dup(fd), "r");
 148         while (!feof(fp)) {
 149                 p = fgets(buf, MAX_CMDLEN, fp);
 150                 if (!p)
 151                         break;
 152
 153                 idx = strlen(p) - 1;
 154                 if (p[idx] == '\n')
 155                         p[idx] = '\0';
 156                 ret = strlist__add(sl, buf);
 157                 if (ret < 0) {
 158                         pr_debug("strlist__add failed (%d)\n", ret);
 159                         strlist__delete(sl);
 160                         return NULL;
 161                 }
 162         }
 163         fclose(fp);
 164
 165         return sl;
 166 }
 167
 168 static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
 169 {
 170         char buf[128];
 171         struct strlist *sl, *rawlist;
 172         struct str_node *ent;
 173         struct probe_trace_event tev;
 174         int ret = 0;
 175
 176         memset(&tev, 0, sizeof(tev));
 177         rawlist = probe_file__get_rawlist(fd);
 178         if (!rawlist)
 179                 return NULL;
 180         sl = strlist__new(NULL, NULL);
 181         strlist__for_each_entry(ent, rawlist) {
 182                 ret = parse_probe_trace_command(ent->s, &tev);
 183                 if (ret < 0)
 184                         break;
 185                 if (include_group) {
 186                         ret = e_snprintf(buf, 128, "%s:%s", tev.group,
 187                                         tev.event);
 188                         if (ret >= 0)
 189                                 ret = strlist__add(sl, buf);
 190                 } else
 191                         ret = strlist__add(sl, tev.event);
 192                 clear_probe_trace_event(&tev);
 193                 if (ret < 0)
 194                         break;
 195         }
 196         strlist__delete(rawlist);
 197
 198         if (ret < 0) {
 199                 strlist__delete(sl);
 200                 return NULL;
 201         }
 202         return sl;
 203 }
 204
 205 /* Get current perf-probe event names */
 206 struct strlist *probe_file__get_namelist(int fd)
 207 {
 208         return __probe_file__get_namelist(fd, false);
 209 }
 210
 211 int probe_file__add_event(int fd, struct probe_trace_event *tev)
 212 {
 213         int ret = 0;
 214         char *buf = synthesize_probe_trace_command(tev);
 215         char sbuf[STRERR_BUFSIZE];
 216
 217         if (!buf) {
 218                 pr_debug("Failed to synthesize probe trace event.\n");
 219                 return -EINVAL;
 220         }
 221
 222         pr_debug("Writing event: %s\n", buf);
 223         if (!probe_event_dry_run) {
 224                 if (write(fd, buf, strlen(buf)) < (int)strlen(buf)) {
 225                         ret = -errno;
 226                         pr_warning("Failed to write event: %s\n",
 227                                    str_error_r(errno, sbuf, sizeof(sbuf)));
 228                 }
 229         }
 230         free(buf);
 231
 232         return ret;
 233 }
 234
 235 static int __del_trace_probe_event(int fd, struct str_node *ent)
 236 {
 237         char *p;
 238         char buf[128];
 239         int ret;
 240
 241         /* Convert from perf-probe event to trace-probe event */
 242         ret = e_snprintf(buf, 128, "-:%s", ent->s);
 243         if (ret < 0)
 244                 goto error;
 245
 246         p = strchr(buf + 2, ':');
 247         if (!p) {
 248                 pr_debug("Internal error: %s should have ':' but not.\n",
 249                          ent->s);
 250                 ret = -ENOTSUP;
 251                 goto error;
 252         }
 253         *p = '/';
 254
 255         pr_debug("Writing event: %s\n", buf);
 256         ret = write(fd, buf, strlen(buf));
 257         if (ret < 0) {
 258                 ret = -errno;
 259                 goto error;
 260         }
 261
 262         return 0;
 263 error:
 264         pr_warning("Failed to delete event: %s\n",
 265                    str_error_r(-ret, buf, sizeof(buf)));
 266         return ret;
 267 }
 268
 269 int probe_file__get_events(int fd, struct strfilter *filter,
 270                            struct strlist *plist)
 271 {
 272         struct strlist *namelist;
 273         struct str_node *ent;
 274         const char *p;
 275         int ret = -ENOENT;
 276
 277         if (!plist)
 278                 return -EINVAL;
 279
 280         namelist = __probe_file__get_namelist(fd, true);
 281         if (!namelist)
 282                 return -ENOENT;
 283
 284         strlist__for_each_entry(ent, namelist) {
 285                 p = strchr(ent->s, ':');
 286                 if ((p && strfilter__compare(filter, p + 1)) ||
 287                     strfilter__compare(filter, ent->s)) {
 288                         strlist__add(plist, ent->s);
 289                         ret = 0;
 290                 }
 291         }
 292         strlist__delete(namelist);
 293
 294         return ret;
 295 }
 296
 297 int probe_file__del_strlist(int fd, struct strlist *namelist)
 298 {
 299         int ret = 0;
 300         struct str_node *ent;
 301
 302         strlist__for_each_entry(ent, namelist) {
 303                 ret = __del_trace_probe_event(fd, ent);
 304                 if (ret < 0)
 305                         break;
 306         }
 307         return ret;
 308 }
 309
 310 int probe_file__del_events(int fd, struct strfilter *filter)
 311 {
 312         struct strlist *namelist;
 313         int ret;
 314
 315         namelist = strlist__new(NULL, NULL);
 316         if (!namelist)
 317                 return -ENOMEM;
 318
 319         ret = probe_file__get_events(fd, filter, namelist);
 320         if (ret < 0)
 321                 return ret;
 322
 323         ret = probe_file__del_strlist(fd, namelist);
 324         strlist__delete(namelist);
 325
 326         return ret;
 327 }
 328
 329 /* Caller must ensure to remove this entry from list */
 330 static void probe_cache_entry__delete(struct probe_cache_entry *entry)
 331 {
 332         if (entry) {
 333                 BUG_ON(!list_empty(&entry->node));
 334
 335                 strlist__delete(entry->tevlist);
 336                 clear_perf_probe_event(&entry->pev);
 337                 zfree(&entry->spev);
 338                 free(entry);
 339         }
 340 }
 341
 342 static struct probe_cache_entry *
 343 probe_cache_entry__new(struct perf_probe_event *pev)
 344 {
 345         struct probe_cache_entry *entry = zalloc(sizeof(*entry));
 346
 347         if (entry) {
 348                 INIT_LIST_HEAD(&entry->node);
 349                 entry->tevlist = strlist__new(NULL, NULL);
 350                 if (!entry->tevlist)
 351                         zfree(&entry);
 352                 else if (pev) {
 353                         entry->spev = synthesize_perf_probe_command(pev);
 354                         if (!entry->spev ||
 355                             perf_probe_event__copy(&entry->pev, pev) < 0) {
 356                                 probe_cache_entry__delete(entry);
 357                                 return NULL;
 358                         }
 359                 }
 360         }
 361
 362         return entry;
 363 }
 364
 365 int probe_cache_entry__get_event(struct probe_cache_entry *entry,
 366                                  struct probe_trace_event **tevs)
 367 {
 368         struct probe_trace_event *tev;
 369         struct str_node *node;
 370         int ret, i;
 371
 372         ret = strlist__nr_entries(entry->tevlist);
 373         if (ret > probe_conf.max_probes)
 374                 return -E2BIG;
 375
 376         *tevs = zalloc(ret * sizeof(*tev));
 377         if (!*tevs)
 378                 return -ENOMEM;
 379
 380         i = 0;
 381         strlist__for_each_entry(node, entry->tevlist) {
 382                 tev = &(*tevs)[i++];
 383                 ret = parse_probe_trace_command(node->s, tev);
 384                 if (ret < 0)
 385                         break;
 386         }
 387         return i;
 388 }
 389
 390 /* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
 391 static int probe_cache__open(struct probe_cache *pcache, const char *target)
 392 {
 393         char cpath[PATH_MAX];
 394         char sbuildid[SBUILD_ID_SIZE];
 395         char *dir_name = NULL;
 396         bool is_kallsyms = false;
 397         int ret, fd;
 398
 399         if (target && build_id_cache__cached(target)) {
 400                 /* This is a cached buildid */
 401                 strncpy(sbuildid, target, SBUILD_ID_SIZE);
 402                 dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
 403                 goto found;
 404         }
 405
 406         if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
 407                 target = DSO__NAME_KALLSYMS;
 408                 is_kallsyms = true;
 409                 ret = sysfs__sprintf_build_id("/", sbuildid);
 410         } else
 411                 ret = filename__sprintf_build_id(target, sbuildid);
 412
 413         if (ret < 0) {
 414                 pr_debug("Failed to get build-id from %s.\n", target);
 415                 return ret;
 416         }
 417
 418         /* If we have no buildid cache, make it */
 419         if (!build_id_cache__cached(sbuildid)) {
 420                 ret = build_id_cache__add_s(sbuildid, target,
 421                                             is_kallsyms, NULL);
 422                 if (ret < 0) {
 423                         pr_debug("Failed to add build-id cache: %s\n", target);
 424                         return ret;
 425                 }
 426         }
 427
 428         dir_name = build_id_cache__cachedir(sbuildid, target, is_kallsyms,
 429                                             false);
 430 found:
 431         if (!dir_name) {
 432                 pr_debug("Failed to get cache from %s\n", target);
 433                 return -ENOMEM;
 434         }
 435
 436         snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
 437         fd = open(cpath, O_CREAT | O_RDWR, 0644);
 438         if (fd < 0)
 439                 pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
 440         free(dir_name);
 441         pcache->fd = fd;
 442
 443         return fd;
 444 }
 445
 446 static int probe_cache__load(struct probe_cache *pcache)
 447 {
 448         struct probe_cache_entry *entry = NULL;
 449         char buf[MAX_CMDLEN], *p;
 450         int ret = 0;
 451         FILE *fp;
 452
 453         fp = fdopen(dup(pcache->fd), "r");
 454         if (!fp)
 455                 return -EINVAL;
 456
 457         while (!feof(fp)) {
 458                 if (!fgets(buf, MAX_CMDLEN, fp))
 459                         break;
 460                 p = strchr(buf, '\n');
 461                 if (p)
 462                         *p = '\0';
 463                 /* #perf_probe_event or %sdt_event */
 464                 if (buf[0] == '#' || buf[0] == '%') {
 465                         entry = probe_cache_entry__new(NULL);
 466                         if (!entry) {
 467                                 ret = -ENOMEM;
 468                                 goto out;
 469                         }
 470                         if (buf[0] == '%')
 471                                 entry->sdt = true;
 472                         entry->spev = strdup(buf + 1);
 473                         if (entry->spev)
 474                                 ret = parse_perf_probe_command(buf + 1,
 475                                                                 &entry->pev);
 476                         else
 477                                 ret = -ENOMEM;
 478                         if (ret < 0) {
 479                                 probe_cache_entry__delete(entry);
 480                                 goto out;
 481                         }
 482                         list_add_tail(&entry->node, &pcache->entries);
 483                 } else {        /* trace_probe_event */
 484                         if (!entry) {
 485                                 ret = -EINVAL;
 486                                 goto out;
 487                         }
 488                         strlist__add(entry->tevlist, buf);
 489                 }
 490         }
 491 out:
 492         fclose(fp);
 493         return ret;
 494 }
 495
 496 static struct probe_cache *probe_cache__alloc(void)
 497 {
 498         struct probe_cache *pcache = zalloc(sizeof(*pcache));
 499
 500         if (pcache) {
 501                 INIT_LIST_HEAD(&pcache->entries);
 502                 pcache->fd = -EINVAL;
 503         }
 504         return pcache;
 505 }
 506
 507 void probe_cache__purge(struct probe_cache *pcache)
 508 {
 509         struct probe_cache_entry *entry, *n;
 510
 511         list_for_each_entry_safe(entry, n, &pcache->entries, node) {
 512                 list_del_init(&entry->node);
 513                 probe_cache_entry__delete(entry);
 514         }
 515 }
 516
 517 void probe_cache__delete(struct probe_cache *pcache)
 518 {
 519         if (!pcache)
 520                 return;
 521
 522         probe_cache__purge(pcache);
 523         if (pcache->fd > 0)
 524                 close(pcache->fd);
 525         free(pcache);
 526 }
 527
 528 struct probe_cache *probe_cache__new(const char *target)
 529 {
 530         struct probe_cache *pcache = probe_cache__alloc();
 531         int ret;
 532
 533         if (!pcache)
 534                 return NULL;
 535
 536         ret = probe_cache__open(pcache, target);
 537         if (ret < 0) {
 538                 pr_debug("Cache open error: %d\n", ret);
 539                 goto out_err;
 540         }
 541
 542         ret = probe_cache__load(pcache);
 543         if (ret < 0) {
 544                 pr_debug("Cache read error: %d\n", ret);
 545                 goto out_err;
 546         }
 547
 548         return pcache;
 549
 550 out_err:
 551         probe_cache__delete(pcache);
 552         return NULL;
 553 }
 554
 555 static bool streql(const char *a, const char *b)
 556 {
 557         if (a == b)
 558                 return true;
 559
 560         if (!a || !b)
 561                 return false;
 562
 563         return !strcmp(a, b);
 564 }
 565
 566 struct probe_cache_entry *
 567 probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
 568 {
 569         struct probe_cache_entry *entry = NULL;
 570         char *cmd = synthesize_perf_probe_command(pev);
 571
 572         if (!cmd)
 573                 return NULL;
 574
 575         for_each_probe_cache_entry(entry, pcache) {
 576                 if (pev->sdt) {
 577                         if (entry->pev.event &&
 578                             streql(entry->pev.event, pev->event) &&
 579                             (!pev->group ||
 580                              streql(entry->pev.group, pev->group)))
 581                                 goto found;
 582
 583                         continue;
 584                 }
 585                 /* Hit if same event name or same command-string */
 586                 if ((pev->event &&
 587                      (streql(entry->pev.group, pev->group) &&
 588                       streql(entry->pev.event, pev->event))) ||
 589                     (!strcmp(entry->spev, cmd)))
 590                         goto found;
 591         }
 592         entry = NULL;
 593
 594 found:
 595         free(cmd);
 596         return entry;
 597 }
 598
 599 struct probe_cache_entry *
 600 probe_cache__find_by_name(struct probe_cache *pcache,
 601                           const char *group, const char *event)
 602 {
 603         struct probe_cache_entry *entry = NULL;
 604
 605         for_each_probe_cache_entry(entry, pcache) {
 606                 /* Hit if same event name or same command-string */
 607                 if (streql(entry->pev.group, group) &&
 608                     streql(entry->pev.event, event))
 609                         goto found;
 610         }
 611         entry = NULL;
 612
 613 found:
 614         return entry;
 615 }
 616
 617 int probe_cache__add_entry(struct probe_cache *pcache,
 618                            struct perf_probe_event *pev,
 619                            struct probe_trace_event *tevs, int ntevs)
 620 {
 621         struct probe_cache_entry *entry = NULL;
 622         char *command;
 623         int i, ret = 0;
 624
 625         if (!pcache || !pev || !tevs || ntevs <= 0) {
 626                 ret = -EINVAL;
 627                 goto out_err;
 628         }
 629
 630         /* Remove old cache entry */
 631         entry = probe_cache__find(pcache, pev);
 632         if (entry) {
 633                 list_del_init(&entry->node);
 634                 probe_cache_entry__delete(entry);
 635         }
 636
 637         ret = -ENOMEM;
 638         entry = probe_cache_entry__new(pev);
 639         if (!entry)
 640                 goto out_err;
 641
 642         for (i = 0; i < ntevs; i++) {
 643                 if (!tevs[i].point.symbol)
 644                         continue;
 645
 646                 command = synthesize_probe_trace_command(&tevs[i]);
 647                 if (!command)
 648                         goto out_err;
 649                 strlist__add(entry->tevlist, command);
 650                 free(command);
 651         }
 652         list_add_tail(&entry->node, &pcache->entries);
 653         pr_debug("Added probe cache: %d\n", ntevs);
 654         return 0;
 655
 656 out_err:
 657         pr_debug("Failed to add probe caches\n");
 658         probe_cache_entry__delete(entry);
 659         return ret;
 660 }
 661
 662 #ifdef HAVE_GELF_GETNOTE_SUPPORT
 663 static unsigned long long sdt_note__get_addr(struct sdt_note *note)
 664 {
 665         return note->bit32 ? (unsigned long long)note->addr.a32[0]
 666                  : (unsigned long long)note->addr.a64[0];
 667 }
 668
 669 int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname)
 670 {
 671         struct probe_cache_entry *entry = NULL;
 672         struct list_head sdtlist;
 673         struct sdt_note *note;
 674         char *buf;
 675         char sdtgrp[64];
 676         int ret;
 677
 678         INIT_LIST_HEAD(&sdtlist);
 679         ret = get_sdt_note_list(&sdtlist, pathname);
 680         if (ret < 0) {
 681                 pr_debug("Failed to get sdt note: %d\n", ret);
 682                 return ret;
 683         }
 684         list_for_each_entry(note, &sdtlist, note_list) {
 685                 ret = snprintf(sdtgrp, 64, "sdt_%s", note->provider);
 686                 if (ret < 0)
 687                         break;
 688                 /* Try to find same-name entry */
 689                 entry = probe_cache__find_by_name(pcache, sdtgrp, note->name);
 690                 if (!entry) {
 691                         entry = probe_cache_entry__new(NULL);
 692                         if (!entry) {
 693                                 ret = -ENOMEM;
 694                                 break;
 695                         }
 696                         entry->sdt = true;
 697                         ret = asprintf(&entry->spev, "%s:%s=%s", sdtgrp,
 698                                         note->name, note->name);
 699                         if (ret < 0)
 700                                 break;
 701                         entry->pev.event = strdup(note->name);
 702                         entry->pev.group = strdup(sdtgrp);
 703                         list_add_tail(&entry->node, &pcache->entries);
 704                 }
 705                 ret = asprintf(&buf, "p:%s/%s %s:0x%llx",
 706                                 sdtgrp, note->name, pathname,
 707                                 sdt_note__get_addr(note));
 708                 if (ret < 0)
 709                         break;
 710                 strlist__add(entry->tevlist, buf);
 711                 free(buf);
 712                 entry = NULL;
 713         }
 714         if (entry) {
 715                 list_del_init(&entry->node);
 716                 probe_cache_entry__delete(entry);
 717         }
 718         cleanup_sdt_note_list(&sdtlist);
 719         return ret;
 720 }
 721 #endif
 722
 723 static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
 724 {
 725         struct str_node *snode;
 726         struct stat st;
 727         struct iovec iov[3];
 728         const char *prefix = entry->sdt ? "%" : "#";
 729         int ret;
 730         /* Save stat for rollback */
 731         ret = fstat(fd, &st);
 732         if (ret < 0)
 733                 return ret;
 734
 735         pr_debug("Writing cache: %s%s\n", prefix, entry->spev);
 736         iov[0].iov_base = (void *)prefix; iov[0].iov_len = 1;
 737         iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
 738         iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
 739         ret = writev(fd, iov, 3);
 740         if (ret < (int)iov[1].iov_len + 2)
 741                 goto rollback;
 742
 743         strlist__for_each_entry(snode, entry->tevlist) {
 744                 iov[0].iov_base = (void *)snode->s;
 745                 iov[0].iov_len = strlen(snode->s);
 746                 iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
 747                 ret = writev(fd, iov, 2);
 748                 if (ret < (int)iov[0].iov_len + 1)
 749                         goto rollback;
 750         }
 751         return 0;
 752
 753 rollback:
 754         /* Rollback to avoid cache file corruption */
 755         if (ret > 0)
 756                 ret = -1;
 757         if (ftruncate(fd, st.st_size) < 0)
 758                 ret = -2;
 759
 760         return ret;
 761 }
 762
 763 int probe_cache__commit(struct probe_cache *pcache)
 764 {
 765         struct probe_cache_entry *entry;
 766         int ret = 0;
 767
 768         /* TBD: if we do not update existing entries, skip it */
 769         ret = lseek(pcache->fd, 0, SEEK_SET);
 770         if (ret < 0)
 771                 goto out;
 772
 773         ret = ftruncate(pcache->fd, 0);
 774         if (ret < 0)
 775                 goto out;
 776
 777         for_each_probe_cache_entry(entry, pcache) {
 778                 ret = probe_cache_entry__write(entry, pcache->fd);
 779                 pr_debug("Cache committed: %d\n", ret);
 780                 if (ret < 0)
 781                         break;
 782         }
 783 out:
 784         return ret;
 785 }
 786
 787 static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
 788                                        struct strfilter *filter)
 789 {
 790         char buf[128], *ptr = entry->spev;
 791
 792         if (entry->pev.event) {
 793                 snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
 794                 ptr = buf;
 795         }
 796         return strfilter__compare(filter, ptr);
 797 }
 798
 799 int probe_cache__filter_purge(struct probe_cache *pcache,
 800                               struct strfilter *filter)
 801 {
 802         struct probe_cache_entry *entry, *tmp;
 803
 804         list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
 805                 if (probe_cache_entry__compare(entry, filter)) {
 806                         pr_info("Removed cached event: %s\n", entry->spev);
 807                         list_del_init(&entry->node);
 808                         probe_cache_entry__delete(entry);
 809                 }
 810         }
 811         return 0;
 812 }
 813
 814 static int probe_cache__show_entries(struct probe_cache *pcache,
 815                                      struct strfilter *filter)
 816 {
 817         struct probe_cache_entry *entry;
 818
 819         for_each_probe_cache_entry(entry, pcache) {
 820                 if (probe_cache_entry__compare(entry, filter))
 821                         printf("%s\n", entry->spev);
 822         }
 823         return 0;
 824 }
 825
 826 /* Show all cached probes */
 827 int probe_cache__show_all_caches(struct strfilter *filter)
 828 {
 829         struct probe_cache *pcache;
 830         struct strlist *bidlist;
 831         struct str_node *nd;
 832         char *buf = strfilter__string(filter);
 833
 834         pr_debug("list cache with filter: %s\n", buf);
 835         free(buf);
 836
 837         bidlist = build_id_cache__list_all(true);
 838         if (!bidlist) {
 839                 pr_debug("Failed to get buildids: %d\n", errno);
 840                 return -EINVAL;
 841         }
 842         strlist__for_each_entry(nd, bidlist) {
 843                 pcache = probe_cache__new(nd->s);
 844                 if (!pcache)
 845                         continue;
 846                 if (!list_empty(&pcache->entries)) {
 847                         buf = build_id_cache__origname(nd->s);
 848                         printf("%s (%s):\n", buf, nd->s);
 849                         free(buf);
 850                         probe_cache__show_entries(pcache, filter);
 851                 }
 852                 probe_cache__delete(pcache);
 853         }
 854         strlist__delete(bidlist);
 855
 856         return 0;
 857 }