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 <errno.h>
  18 #include <fcntl.h>
  19 #include <sys/stat.h>
  20 #include <sys/types.h>
  21 #include <sys/uio.h>
  22 #include <unistd.h>
  23 #include "namespaces.h"
  24 #include "util.h"
  25 #include "event.h"
  26 #include "strlist.h"
  27 #include "strfilter.h"
  28 #include "debug.h"
  29 #include "cache.h"
  30 #include "color.h"
  31 #include "symbol.h"
  32 #include "thread.h"
  33 #include <api/fs/tracing_path.h>
  34 #include "probe-event.h"
  35 #include "probe-file.h"
  36 #include "session.h"
  37 #include "perf_regs.h"
  38 #include "string2.h"
  39
  40 /* 4096 - 2 ('\n' + '\0') */
  41 #define MAX_CMDLEN 4094
  42
  43 static void print_open_warning(int err, bool uprobe)
  44 {
  45         char sbuf[STRERR_BUFSIZE];
  46
  47         if (err == -ENOENT) {
  48                 const char *config;
  49
  50                 if (uprobe)
  51                         config = "CONFIG_UPROBE_EVENTS";
  52                 else
  53                         config = "CONFIG_KPROBE_EVENTS";
  54
  55                 pr_warning("%cprobe_events file does not exist"
  56                            " - please rebuild kernel with %s.\n",
  57                            uprobe ? 'u' : 'k', config);
  58         } else if (err == -ENOTSUP)
  59                 pr_warning("Tracefs or debugfs is not mounted.\n");
  60         else
  61                 pr_warning("Failed to open %cprobe_events: %s\n",
  62                            uprobe ? 'u' : 'k',
  63                            str_error_r(-err, sbuf, sizeof(sbuf)));
  64 }
  65
  66 static void print_both_open_warning(int kerr, int uerr)
  67 {
  68         /* Both kprobes and uprobes are disabled, warn it. */
  69         if (kerr == -ENOTSUP && uerr == -ENOTSUP)
  70                 pr_warning("Tracefs or debugfs is not mounted.\n");
  71         else if (kerr == -ENOENT && uerr == -ENOENT)
  72                 pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
  73                            "or/and CONFIG_UPROBE_EVENTS.\n");
  74         else {
  75                 char sbuf[STRERR_BUFSIZE];
  76                 pr_warning("Failed to open kprobe events: %s.\n",
  77                            str_error_r(-kerr, sbuf, sizeof(sbuf)));
  78                 pr_warning("Failed to open uprobe events: %s.\n",
  79                            str_error_r(-uerr, sbuf, sizeof(sbuf)));
  80         }
  81 }
  82
  83 int open_trace_file(const char *trace_file, bool readwrite)
  84 {
  85         char buf[PATH_MAX];
  86         int ret;
  87
  88         ret = e_snprintf(buf, PATH_MAX, "%s/%s", tracing_path_mount(), trace_file);
  89         if (ret >= 0) {
  90                 pr_debug("Opening %s write=%d\n", buf, readwrite);
  91                 if (readwrite && !probe_event_dry_run)
  92                         ret = open(buf, O_RDWR | O_APPEND, 0);
  93                 else
  94                         ret = open(buf, O_RDONLY, 0);
  95
  96                 if (ret < 0)
  97                         ret = -errno;
  98         }
  99         return ret;
 100 }
 101
 102 static int open_kprobe_events(bool readwrite)
 103 {
 104         return open_trace_file("kprobe_events", readwrite);
 105 }
 106
 107 static int open_uprobe_events(bool readwrite)
 108 {
 109         return open_trace_file("uprobe_events", readwrite);
 110 }
 111
 112 int probe_file__open(int flag)
 113 {
 114         int fd;
 115
 116         if (flag & PF_FL_UPROBE)
 117                 fd = open_uprobe_events(flag & PF_FL_RW);
 118         else
 119                 fd = open_kprobe_events(flag & PF_FL_RW);
 120         if (fd < 0)
 121                 print_open_warning(fd, flag & PF_FL_UPROBE);
 122
 123         return fd;
 124 }
 125
 126 int probe_file__open_both(int *kfd, int *ufd, int flag)
 127 {
 128         if (!kfd || !ufd)
 129                 return -EINVAL;
 130
 131         *kfd = open_kprobe_events(flag & PF_FL_RW);
 132         *ufd = open_uprobe_events(flag & PF_FL_RW);
 133         if (*kfd < 0 && *ufd < 0) {
 134                 print_both_open_warning(*kfd, *ufd);
 135                 return *kfd;
 136         }
 137
 138         return 0;
 139 }
 140
 141 /* Get raw string list of current kprobe_events  or uprobe_events */
 142 struct strlist *probe_file__get_rawlist(int fd)
 143 {
 144         int ret, idx, fddup;
 145         FILE *fp;
 146         char buf[MAX_CMDLEN];
 147         char *p;
 148         struct strlist *sl;
 149
 150         if (fd < 0)
 151                 return NULL;
 152
 153         sl = strlist__new(NULL, NULL);
 154         if (sl == NULL)
 155                 return NULL;
 156
 157         fddup = dup(fd);
 158         if (fddup < 0)
 159                 goto out_free_sl;
 160
 161         fp = fdopen(fddup, "r");
 162         if (!fp)
 163                 goto out_close_fddup;
 164
 165         while (!feof(fp)) {
 166                 p = fgets(buf, MAX_CMDLEN, fp);
 167                 if (!p)
 168                         break;
 169
 170                 idx = strlen(p) - 1;
 171                 if (p[idx] == '\n')
 172                         p[idx] = '\0';
 173                 ret = strlist__add(sl, buf);
 174                 if (ret < 0) {
 175                         pr_debug("strlist__add failed (%d)\n", ret);
 176                         goto out_close_fp;
 177                 }
 178         }
 179         fclose(fp);
 180
 181         return sl;
 182
 183 out_close_fp:
 184         fclose(fp);
 185         goto out_free_sl;
 186 out_close_fddup:
 187         close(fddup);
 188 out_free_sl:
 189         strlist__delete(sl);
 190         return NULL;
 191 }
 192
 193 static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
 194 {
 195         char buf[128];
 196         struct strlist *sl, *rawlist;
 197         struct str_node *ent;
 198         struct probe_trace_event tev;
 199         int ret = 0;
 200
 201         memset(&tev, 0, sizeof(tev));
 202         rawlist = probe_file__get_rawlist(fd);
 203         if (!rawlist)
 204                 return NULL;
 205         sl = strlist__new(NULL, NULL);
 206         strlist__for_each_entry(ent, rawlist) {
 207                 ret = parse_probe_trace_command(ent->s, &tev);
 208                 if (ret < 0)
 209                         break;
 210                 if (include_group) {
 211                         ret = e_snprintf(buf, 128, "%s:%s", tev.group,
 212                                         tev.event);
 213                         if (ret >= 0)
 214                                 ret = strlist__add(sl, buf);
 215                 } else
 216                         ret = strlist__add(sl, tev.event);
 217                 clear_probe_trace_event(&tev);
 218                 if (ret < 0)
 219                         break;
 220         }
 221         strlist__delete(rawlist);
 222
 223         if (ret < 0) {
 224                 strlist__delete(sl);
 225                 return NULL;
 226         }
 227         return sl;
 228 }
 229
 230 /* Get current perf-probe event names */
 231 struct strlist *probe_file__get_namelist(int fd)
 232 {
 233         return __probe_file__get_namelist(fd, false);
 234 }
 235
 236 int probe_file__add_event(int fd, struct probe_trace_event *tev)
 237 {
 238         int ret = 0;
 239         char *buf = synthesize_probe_trace_command(tev);
 240         char sbuf[STRERR_BUFSIZE];
 241
 242         if (!buf) {
 243                 pr_debug("Failed to synthesize probe trace event.\n");
 244                 return -EINVAL;
 245         }
 246
 247         pr_debug("Writing event: %s\n", buf);
 248         if (!probe_event_dry_run) {
 249                 if (write(fd, buf, strlen(buf)) < (int)strlen(buf)) {
 250                         ret = -errno;
 251                         pr_warning("Failed to write event: %s\n",
 252                                    str_error_r(errno, sbuf, sizeof(sbuf)));
 253                 }
 254         }
 255         free(buf);
 256
 257         return ret;
 258 }
 259
 260 static int __del_trace_probe_event(int fd, struct str_node *ent)
 261 {
 262         char *p;
 263         char buf[128];
 264         int ret;
 265
 266         /* Convert from perf-probe event to trace-probe event */
 267         ret = e_snprintf(buf, 128, "-:%s", ent->s);
 268         if (ret < 0)
 269                 goto error;
 270
 271         p = strchr(buf + 2, ':');
 272         if (!p) {
 273                 pr_debug("Internal error: %s should have ':' but not.\n",
 274                          ent->s);
 275                 ret = -ENOTSUP;
 276                 goto error;
 277         }
 278         *p = '/';
 279
 280         pr_debug("Writing event: %s\n", buf);
 281         ret = write(fd, buf, strlen(buf));
 282         if (ret < 0) {
 283                 ret = -errno;
 284                 goto error;
 285         }
 286
 287         return 0;
 288 error:
 289         pr_warning("Failed to delete event: %s\n",
 290                    str_error_r(-ret, buf, sizeof(buf)));
 291         return ret;
 292 }
 293
 294 int probe_file__get_events(int fd, struct strfilter *filter,
 295                            struct strlist *plist)
 296 {
 297         struct strlist *namelist;
 298         struct str_node *ent;
 299         const char *p;
 300         int ret = -ENOENT;
 301
 302         if (!plist)
 303                 return -EINVAL;
 304
 305         namelist = __probe_file__get_namelist(fd, true);
 306         if (!namelist)
 307                 return -ENOENT;
 308
 309         strlist__for_each_entry(ent, namelist) {
 310                 p = strchr(ent->s, ':');
 311                 if ((p && strfilter__compare(filter, p + 1)) ||
 312                     strfilter__compare(filter, ent->s)) {
 313                         strlist__add(plist, ent->s);
 314                         ret = 0;
 315                 }
 316         }
 317         strlist__delete(namelist);
 318
 319         return ret;
 320 }
 321
 322 int probe_file__del_strlist(int fd, struct strlist *namelist)
 323 {
 324         int ret = 0;
 325         struct str_node *ent;
 326
 327         strlist__for_each_entry(ent, namelist) {
 328                 ret = __del_trace_probe_event(fd, ent);
 329                 if (ret < 0)
 330                         break;
 331         }
 332         return ret;
 333 }
 334
 335 int probe_file__del_events(int fd, struct strfilter *filter)
 336 {
 337         struct strlist *namelist;
 338         int ret;
 339
 340         namelist = strlist__new(NULL, NULL);
 341         if (!namelist)
 342                 return -ENOMEM;
 343
 344         ret = probe_file__get_events(fd, filter, namelist);
 345         if (ret < 0)
 346                 return ret;
 347
 348         ret = probe_file__del_strlist(fd, namelist);
 349         strlist__delete(namelist);
 350
 351         return ret;
 352 }
 353
 354 /* Caller must ensure to remove this entry from list */
 355 static void probe_cache_entry__delete(struct probe_cache_entry *entry)
 356 {
 357         if (entry) {
 358                 BUG_ON(!list_empty(&entry->node));
 359
 360                 strlist__delete(entry->tevlist);
 361                 clear_perf_probe_event(&entry->pev);
 362                 zfree(&entry->spev);
 363                 free(entry);
 364         }
 365 }
 366
 367 static struct probe_cache_entry *
 368 probe_cache_entry__new(struct perf_probe_event *pev)
 369 {
 370         struct probe_cache_entry *entry = zalloc(sizeof(*entry));
 371
 372         if (entry) {
 373                 INIT_LIST_HEAD(&entry->node);
 374                 entry->tevlist = strlist__new(NULL, NULL);
 375                 if (!entry->tevlist)
 376                         zfree(&entry);
 377                 else if (pev) {
 378                         entry->spev = synthesize_perf_probe_command(pev);
 379                         if (!entry->spev ||
 380                             perf_probe_event__copy(&entry->pev, pev) < 0) {
 381                                 probe_cache_entry__delete(entry);
 382                                 return NULL;
 383                         }
 384                 }
 385         }
 386
 387         return entry;
 388 }
 389
 390 int probe_cache_entry__get_event(struct probe_cache_entry *entry,
 391                                  struct probe_trace_event **tevs)
 392 {
 393         struct probe_trace_event *tev;
 394         struct str_node *node;
 395         int ret, i;
 396
 397         ret = strlist__nr_entries(entry->tevlist);
 398         if (ret > probe_conf.max_probes)
 399                 return -E2BIG;
 400
 401         *tevs = zalloc(ret * sizeof(*tev));
 402         if (!*tevs)
 403                 return -ENOMEM;
 404
 405         i = 0;
 406         strlist__for_each_entry(node, entry->tevlist) {
 407                 tev = &(*tevs)[i++];
 408                 ret = parse_probe_trace_command(node->s, tev);
 409                 if (ret < 0)
 410                         break;
 411         }
 412         return i;
 413 }
 414
 415 /* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
 416 static int probe_cache__open(struct probe_cache *pcache, const char *target,
 417                              struct nsinfo *nsi)
 418 {
 419         char cpath[PATH_MAX];
 420         char sbuildid[SBUILD_ID_SIZE];
 421         char *dir_name = NULL;
 422         bool is_kallsyms = false;
 423         int ret, fd;
 424         struct nscookie nsc;
 425
 426         if (target && build_id_cache__cached(target)) {
 427                 /* This is a cached buildid */
 428                 strlcpy(sbuildid, target, SBUILD_ID_SIZE);
 429                 dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
 430                 goto found;
 431         }
 432
 433         if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
 434                 target = DSO__NAME_KALLSYMS;
 435                 is_kallsyms = true;
 436                 ret = sysfs__sprintf_build_id("/", sbuildid);
 437         } else {
 438                 nsinfo__mountns_enter(nsi, &nsc);
 439                 ret = filename__sprintf_build_id(target, sbuildid);
 440                 nsinfo__mountns_exit(&nsc);
 441         }
 442
 443         if (ret < 0) {
 444                 pr_debug("Failed to get build-id from %s.\n", target);
 445                 return ret;
 446         }
 447
 448         /* If we have no buildid cache, make it */
 449         if (!build_id_cache__cached(sbuildid)) {
 450                 ret = build_id_cache__add_s(sbuildid, target, nsi,
 451                                             is_kallsyms, NULL);
 452                 if (ret < 0) {
 453                         pr_debug("Failed to add build-id cache: %s\n", target);
 454                         return ret;
 455                 }
 456         }
 457
 458         dir_name = build_id_cache__cachedir(sbuildid, target, nsi, is_kallsyms,
 459                                             false);
 460 found:
 461         if (!dir_name) {
 462                 pr_debug("Failed to get cache from %s\n", target);
 463                 return -ENOMEM;
 464         }
 465
 466         snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
 467         fd = open(cpath, O_CREAT | O_RDWR, 0644);
 468         if (fd < 0)
 469                 pr_debug("Failed to open cache(%d): %s\n", fd, cpath);
 470         free(dir_name);
 471         pcache->fd = fd;
 472
 473         return fd;
 474 }
 475
 476 static int probe_cache__load(struct probe_cache *pcache)
 477 {
 478         struct probe_cache_entry *entry = NULL;
 479         char buf[MAX_CMDLEN], *p;
 480         int ret = 0, fddup;
 481         FILE *fp;
 482
 483         fddup = dup(pcache->fd);
 484         if (fddup < 0)
 485                 return -errno;
 486         fp = fdopen(fddup, "r");
 487         if (!fp) {
 488                 close(fddup);
 489                 return -EINVAL;
 490         }
 491
 492         while (!feof(fp)) {
 493                 if (!fgets(buf, MAX_CMDLEN, fp))
 494                         break;
 495                 p = strchr(buf, '\n');
 496                 if (p)
 497                         *p = '\0';
 498                 /* #perf_probe_event or %sdt_event */
 499                 if (buf[0] == '#' || buf[0] == '%') {
 500                         entry = probe_cache_entry__new(NULL);
 501                         if (!entry) {
 502                                 ret = -ENOMEM;
 503                                 goto out;
 504                         }
 505                         if (buf[0] == '%')
 506                                 entry->sdt = true;
 507                         entry->spev = strdup(buf + 1);
 508                         if (entry->spev)
 509                                 ret = parse_perf_probe_command(buf + 1,
 510                                                                 &entry->pev);
 511                         else
 512                                 ret = -ENOMEM;
 513                         if (ret < 0) {
 514                                 probe_cache_entry__delete(entry);
 515                                 goto out;
 516                         }
 517                         list_add_tail(&entry->node, &pcache->entries);
 518                 } else {        /* trace_probe_event */
 519                         if (!entry) {
 520                                 ret = -EINVAL;
 521                                 goto out;
 522                         }
 523                         strlist__add(entry->tevlist, buf);
 524                 }
 525         }
 526 out:
 527         fclose(fp);
 528         return ret;
 529 }
 530
 531 static struct probe_cache *probe_cache__alloc(void)
 532 {
 533         struct probe_cache *pcache = zalloc(sizeof(*pcache));
 534
 535         if (pcache) {
 536                 INIT_LIST_HEAD(&pcache->entries);
 537                 pcache->fd = -EINVAL;
 538         }
 539         return pcache;
 540 }
 541
 542 void probe_cache__purge(struct probe_cache *pcache)
 543 {
 544         struct probe_cache_entry *entry, *n;
 545
 546         list_for_each_entry_safe(entry, n, &pcache->entries, node) {
 547                 list_del_init(&entry->node);
 548                 probe_cache_entry__delete(entry);
 549         }
 550 }
 551
 552 void probe_cache__delete(struct probe_cache *pcache)
 553 {
 554         if (!pcache)
 555                 return;
 556
 557         probe_cache__purge(pcache);
 558         if (pcache->fd > 0)
 559                 close(pcache->fd);
 560         free(pcache);
 561 }
 562
 563 struct probe_cache *probe_cache__new(const char *target, struct nsinfo *nsi)
 564 {
 565         struct probe_cache *pcache = probe_cache__alloc();
 566         int ret;
 567
 568         if (!pcache)
 569                 return NULL;
 570
 571         ret = probe_cache__open(pcache, target, nsi);
 572         if (ret < 0) {
 573                 pr_debug("Cache open error: %d\n", ret);
 574                 goto out_err;
 575         }
 576
 577         ret = probe_cache__load(pcache);
 578         if (ret < 0) {
 579                 pr_debug("Cache read error: %d\n", ret);
 580                 goto out_err;
 581         }
 582
 583         return pcache;
 584
 585 out_err:
 586         probe_cache__delete(pcache);
 587         return NULL;
 588 }
 589
 590 static bool streql(const char *a, const char *b)
 591 {
 592         if (a == b)
 593                 return true;
 594
 595         if (!a || !b)
 596                 return false;
 597
 598         return !strcmp(a, b);
 599 }
 600
 601 struct probe_cache_entry *
 602 probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
 603 {
 604         struct probe_cache_entry *entry = NULL;
 605         char *cmd = synthesize_perf_probe_command(pev);
 606
 607         if (!cmd)
 608                 return NULL;
 609
 610         for_each_probe_cache_entry(entry, pcache) {
 611                 if (pev->sdt) {
 612                         if (entry->pev.event &&
 613                             streql(entry->pev.event, pev->event) &&
 614                             (!pev->group ||
 615                              streql(entry->pev.group, pev->group)))
 616                                 goto found;
 617
 618                         continue;
 619                 }
 620                 /* Hit if same event name or same command-string */
 621                 if ((pev->event &&
 622                      (streql(entry->pev.group, pev->group) &&
 623                       streql(entry->pev.event, pev->event))) ||
 624                     (!strcmp(entry->spev, cmd)))
 625                         goto found;
 626         }
 627         entry = NULL;
 628
 629 found:
 630         free(cmd);
 631         return entry;
 632 }
 633
 634 struct probe_cache_entry *
 635 probe_cache__find_by_name(struct probe_cache *pcache,
 636                           const char *group, const char *event)
 637 {
 638         struct probe_cache_entry *entry = NULL;
 639
 640         for_each_probe_cache_entry(entry, pcache) {
 641                 /* Hit if same event name or same command-string */
 642                 if (streql(entry->pev.group, group) &&
 643                     streql(entry->pev.event, event))
 644                         goto found;
 645         }
 646         entry = NULL;
 647
 648 found:
 649         return entry;
 650 }
 651
 652 int probe_cache__add_entry(struct probe_cache *pcache,
 653                            struct perf_probe_event *pev,
 654                            struct probe_trace_event *tevs, int ntevs)
 655 {
 656         struct probe_cache_entry *entry = NULL;
 657         char *command;
 658         int i, ret = 0;
 659
 660         if (!pcache || !pev || !tevs || ntevs <= 0) {
 661                 ret = -EINVAL;
 662                 goto out_err;
 663         }
 664
 665         /* Remove old cache entry */
 666         entry = probe_cache__find(pcache, pev);
 667         if (entry) {
 668                 list_del_init(&entry->node);
 669                 probe_cache_entry__delete(entry);
 670         }
 671
 672         ret = -ENOMEM;
 673         entry = probe_cache_entry__new(pev);
 674         if (!entry)
 675                 goto out_err;
 676
 677         for (i = 0; i < ntevs; i++) {
 678                 if (!tevs[i].point.symbol)
 679                         continue;
 680
 681                 command = synthesize_probe_trace_command(&tevs[i]);
 682                 if (!command)
 683                         goto out_err;
 684                 strlist__add(entry->tevlist, command);
 685                 free(command);
 686         }
 687         list_add_tail(&entry->node, &pcache->entries);
 688         pr_debug("Added probe cache: %d\n", ntevs);
 689         return 0;
 690
 691 out_err:
 692         pr_debug("Failed to add probe caches\n");
 693         probe_cache_entry__delete(entry);
 694         return ret;
 695 }
 696
 697 #ifdef HAVE_GELF_GETNOTE_SUPPORT
 698 static unsigned long long sdt_note__get_addr(struct sdt_note *note)
 699 {
 700         return note->bit32 ?
 701                 (unsigned long long)note->addr.a32[SDT_NOTE_IDX_LOC] :
 702                 (unsigned long long)note->addr.a64[SDT_NOTE_IDX_LOC];
 703 }
 704
 705 static unsigned long long sdt_note__get_ref_ctr_offset(struct sdt_note *note)
 706 {
 707         return note->bit32 ?
 708                 (unsigned long long)note->addr.a32[SDT_NOTE_IDX_REFCTR] :
 709                 (unsigned long long)note->addr.a64[SDT_NOTE_IDX_REFCTR];
 710 }
 711
 712 static const char * const type_to_suffix[] = {
 713         ":s64", "", "", "", ":s32", "", ":s16", ":s8",
 714         "", ":u8", ":u16", "", ":u32", "", "", "", ":u64"
 715 };
 716
 717 /*
 718  * Isolate the string number and convert it into a decimal value;
 719  * this will be an index to get suffix of the uprobe name (defining
 720  * the type)
 721  */
 722 static int sdt_arg_parse_size(char *n_ptr, const char **suffix)
 723 {
 724         long type_idx;
 725
 726         type_idx = strtol(n_ptr, NULL, 10);
 727         if (type_idx < -8 || type_idx > 8) {
 728                 pr_debug4("Failed to get a valid sdt type\n");
 729                 return -1;
 730         }
 731
 732         *suffix = type_to_suffix[type_idx + 8];
 733         return 0;
 734 }
 735
 736 static int synthesize_sdt_probe_arg(struct strbuf *buf, int i, const char *arg)
 737 {
 738         char *op, *desc = strdup(arg), *new_op = NULL;
 739         const char *suffix = "";
 740         int ret = -1;
 741
 742         if (desc == NULL) {
 743                 pr_debug4("Allocation error\n");
 744                 return ret;
 745         }
 746
 747         /*
 748          * Argument is in N@OP format. N is size of the argument and OP is
 749          * the actual assembly operand. N can be omitted; in that case
 750          * argument is just OP(without @).
 751          */
 752         op = strchr(desc, '@');
 753         if (op) {
 754                 op[0] = '\0';
 755                 op++;
 756
 757                 if (sdt_arg_parse_size(desc, &suffix))
 758                         goto error;
 759         } else {
 760                 op = desc;
 761         }
 762
 763         ret = arch_sdt_arg_parse_op(op, &new_op);
 764
 765         if (ret < 0)
 766                 goto error;
 767
 768         if (ret == SDT_ARG_VALID) {
 769                 ret = strbuf_addf(buf, " arg%d=%s%s", i + 1, new_op, suffix);
 770                 if (ret < 0)
 771                         goto error;
 772         }
 773
 774         ret = 0;
 775 error:
 776         free(desc);
 777         free(new_op);
 778         return ret;
 779 }
 780
 781 static char *synthesize_sdt_probe_command(struct sdt_note *note,
 782                                         const char *pathname,
 783                                         const char *sdtgrp)
 784 {
 785         struct strbuf buf;
 786         char *ret = NULL, **args;
 787         int i, args_count, err;
 788         unsigned long long ref_ctr_offset;
 789
 790         if (strbuf_init(&buf, 32) < 0)
 791                 return NULL;
 792
 793         err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
 794                         sdtgrp, note->name, pathname,
 795                         sdt_note__get_addr(note));
 796
 797         ref_ctr_offset = sdt_note__get_ref_ctr_offset(note);
 798         if (ref_ctr_offset && err >= 0)
 799                 err = strbuf_addf(&buf, "(0x%llx)", ref_ctr_offset);
 800
 801         if (err < 0)
 802                 goto error;
 803
 804         if (!note->args)
 805                 goto out;
 806
 807         if (note->args) {
 808                 args = argv_split(note->args, &args_count);
 809
 810                 for (i = 0; i < args_count; ++i) {
 811                         if (synthesize_sdt_probe_arg(&buf, i, args[i]) < 0)
 812                                 goto error;
 813                 }
 814         }
 815
 816 out:
 817         ret = strbuf_detach(&buf, NULL);
 818 error:
 819         strbuf_release(&buf);
 820         return ret;
 821 }
 822
 823 int probe_cache__scan_sdt(struct probe_cache *pcache, const char *pathname)
 824 {
 825         struct probe_cache_entry *entry = NULL;
 826         struct list_head sdtlist;
 827         struct sdt_note *note;
 828         char *buf;
 829         char sdtgrp[64];
 830         int ret;
 831
 832         INIT_LIST_HEAD(&sdtlist);
 833         ret = get_sdt_note_list(&sdtlist, pathname);
 834         if (ret < 0) {
 835                 pr_debug4("Failed to get sdt note: %d\n", ret);
 836                 return ret;
 837         }
 838         list_for_each_entry(note, &sdtlist, note_list) {
 839                 ret = snprintf(sdtgrp, 64, "sdt_%s", note->provider);
 840                 if (ret < 0)
 841                         break;
 842                 /* Try to find same-name entry */
 843                 entry = probe_cache__find_by_name(pcache, sdtgrp, note->name);
 844                 if (!entry) {
 845                         entry = probe_cache_entry__new(NULL);
 846                         if (!entry) {
 847                                 ret = -ENOMEM;
 848                                 break;
 849                         }
 850                         entry->sdt = true;
 851                         ret = asprintf(&entry->spev, "%s:%s=%s", sdtgrp,
 852                                         note->name, note->name);
 853                         if (ret < 0)
 854                                 break;
 855                         entry->pev.event = strdup(note->name);
 856                         entry->pev.group = strdup(sdtgrp);
 857                         list_add_tail(&entry->node, &pcache->entries);
 858                 }
 859                 buf = synthesize_sdt_probe_command(note, pathname, sdtgrp);
 860                 if (!buf) {
 861                         ret = -ENOMEM;
 862                         break;
 863                 }
 864
 865                 strlist__add(entry->tevlist, buf);
 866                 free(buf);
 867                 entry = NULL;
 868         }
 869         if (entry) {
 870                 list_del_init(&entry->node);
 871                 probe_cache_entry__delete(entry);
 872         }
 873         cleanup_sdt_note_list(&sdtlist);
 874         return ret;
 875 }
 876 #endif
 877
 878 static int probe_cache_entry__write(struct probe_cache_entry *entry, int fd)
 879 {
 880         struct str_node *snode;
 881         struct stat st;
 882         struct iovec iov[3];
 883         const char *prefix = entry->sdt ? "%" : "#";
 884         int ret;
 885         /* Save stat for rollback */
 886         ret = fstat(fd, &st);
 887         if (ret < 0)
 888                 return ret;
 889
 890         pr_debug("Writing cache: %s%s\n", prefix, entry->spev);
 891         iov[0].iov_base = (void *)prefix; iov[0].iov_len = 1;
 892         iov[1].iov_base = entry->spev; iov[1].iov_len = strlen(entry->spev);
 893         iov[2].iov_base = (void *)"\n"; iov[2].iov_len = 1;
 894         ret = writev(fd, iov, 3);
 895         if (ret < (int)iov[1].iov_len + 2)
 896                 goto rollback;
 897
 898         strlist__for_each_entry(snode, entry->tevlist) {
 899                 iov[0].iov_base = (void *)snode->s;
 900                 iov[0].iov_len = strlen(snode->s);
 901                 iov[1].iov_base = (void *)"\n"; iov[1].iov_len = 1;
 902                 ret = writev(fd, iov, 2);
 903                 if (ret < (int)iov[0].iov_len + 1)
 904                         goto rollback;
 905         }
 906         return 0;
 907
 908 rollback:
 909         /* Rollback to avoid cache file corruption */
 910         if (ret > 0)
 911                 ret = -1;
 912         if (ftruncate(fd, st.st_size) < 0)
 913                 ret = -2;
 914
 915         return ret;
 916 }
 917
 918 int probe_cache__commit(struct probe_cache *pcache)
 919 {
 920         struct probe_cache_entry *entry;
 921         int ret = 0;
 922
 923         /* TBD: if we do not update existing entries, skip it */
 924         ret = lseek(pcache->fd, 0, SEEK_SET);
 925         if (ret < 0)
 926                 goto out;
 927
 928         ret = ftruncate(pcache->fd, 0);
 929         if (ret < 0)
 930                 goto out;
 931
 932         for_each_probe_cache_entry(entry, pcache) {
 933                 ret = probe_cache_entry__write(entry, pcache->fd);
 934                 pr_debug("Cache committed: %d\n", ret);
 935                 if (ret < 0)
 936                         break;
 937         }
 938 out:
 939         return ret;
 940 }
 941
 942 static bool probe_cache_entry__compare(struct probe_cache_entry *entry,
 943                                        struct strfilter *filter)
 944 {
 945         char buf[128], *ptr = entry->spev;
 946
 947         if (entry->pev.event) {
 948                 snprintf(buf, 128, "%s:%s", entry->pev.group, entry->pev.event);
 949                 ptr = buf;
 950         }
 951         return strfilter__compare(filter, ptr);
 952 }
 953
 954 int probe_cache__filter_purge(struct probe_cache *pcache,
 955                               struct strfilter *filter)
 956 {
 957         struct probe_cache_entry *entry, *tmp;
 958
 959         list_for_each_entry_safe(entry, tmp, &pcache->entries, node) {
 960                 if (probe_cache_entry__compare(entry, filter)) {
 961                         pr_info("Removed cached event: %s\n", entry->spev);
 962                         list_del_init(&entry->node);
 963                         probe_cache_entry__delete(entry);
 964                 }
 965         }
 966         return 0;
 967 }
 968
 969 static int probe_cache__show_entries(struct probe_cache *pcache,
 970                                      struct strfilter *filter)
 971 {
 972         struct probe_cache_entry *entry;
 973
 974         for_each_probe_cache_entry(entry, pcache) {
 975                 if (probe_cache_entry__compare(entry, filter))
 976                         printf("%s\n", entry->spev);
 977         }
 978         return 0;
 979 }
 980
 981 /* Show all cached probes */
 982 int probe_cache__show_all_caches(struct strfilter *filter)
 983 {
 984         struct probe_cache *pcache;
 985         struct strlist *bidlist;
 986         struct str_node *nd;
 987         char *buf = strfilter__string(filter);
 988
 989         pr_debug("list cache with filter: %s\n", buf);
 990         free(buf);
 991
 992         bidlist = build_id_cache__list_all(true);
 993         if (!bidlist) {
 994                 pr_debug("Failed to get buildids: %d\n", errno);
 995                 return -EINVAL;
 996         }
 997         strlist__for_each_entry(nd, bidlist) {
 998                 pcache = probe_cache__new(nd->s, NULL);
 999                 if (!pcache)
1000                         continue;
1001                 if (!list_empty(&pcache->entries)) {
1002                         buf = build_id_cache__origname(nd->s);
1003                         printf("%s (%s):\n", buf, nd->s);
1004                         free(buf);
1005                         probe_cache__show_entries(pcache, filter);
1006                 }
1007                 probe_cache__delete(pcache);
1008         }
1009         strlist__delete(bidlist);
1010
1011         return 0;
1012 }
1013
1014 enum ftrace_readme {
1015         FTRACE_README_PROBE_TYPE_X = 0,
1016         FTRACE_README_KRETPROBE_OFFSET,
1017         FTRACE_README_UPROBE_REF_CTR,
1018         FTRACE_README_END,
1019 };
1020
1021 static struct {
1022         const char *pattern;
1023         bool avail;
1024 } ftrace_readme_table[] = {
1025 #define DEFINE_TYPE(idx, pat)                   \
1026         [idx] = {.pattern = pat, .avail = false}
1027         DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"),
1028         DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"),
1029         DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"),
1030 };
1031
1032 static bool scan_ftrace_readme(enum ftrace_readme type)
1033 {
1034         int fd;
1035         FILE *fp;
1036         char *buf = NULL;
1037         size_t len = 0;
1038         bool ret = false;
1039         static bool scanned = false;
1040
1041         if (scanned)
1042                 goto result;
1043
1044         fd = open_trace_file("README", false);
1045         if (fd < 0)
1046                 return ret;
1047
1048         fp = fdopen(fd, "r");
1049         if (!fp) {
1050                 close(fd);
1051                 return ret;
1052         }
1053
1054         while (getline(&buf, &len, fp) > 0)
1055                 for (enum ftrace_readme i = 0; i < FTRACE_README_END; i++)
1056                         if (!ftrace_readme_table[i].avail)
1057                                 ftrace_readme_table[i].avail =
1058                                         strglobmatch(buf, ftrace_readme_table[i].pattern);
1059         scanned = true;
1060
1061         fclose(fp);
1062         free(buf);
1063
1064 result:
1065         if (type >= FTRACE_README_END)
1066                 return false;
1067
1068         return ftrace_readme_table[type].avail;
1069 }
1070
1071 bool probe_type_is_available(enum probe_type type)
1072 {
1073         if (type >= PROBE_TYPE_END)
1074                 return false;
1075         else if (type == PROBE_TYPE_X)
1076                 return scan_ftrace_readme(FTRACE_README_PROBE_TYPE_X);
1077
1078         return true;
1079 }
1080
1081 bool kretprobe_offset_is_supported(void)
1082 {
1083         return scan_ftrace_readme(FTRACE_README_KRETPROBE_OFFSET);
1084 }
1085
1086 bool uprobe_ref_ctr_is_supported(void)
1087 {
1088         return scan_ftrace_readme(FTRACE_README_UPROBE_REF_CTR);
1089 }