tools/perf/util/probe-event.c

   1 /*
   2  * probe-event.c : perf-probe definition to kprobe_events format converter
   3  *
   4  * Written by Masami Hiramatsu <mhiramat@redhat.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  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #define _GNU_SOURCE
  23 #include <sys/utsname.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <unistd.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <limits.h>
  34
  35 #undef _GNU_SOURCE
  36 #include "event.h"
  37 #include "string.h"
  38 #include "strlist.h"
  39 #include "debug.h"
  40 #include "parse-events.h"  /* For debugfs_path */
  41 #include "probe-event.h"
  42
  43 #define MAX_CMDLEN 256
  44 #define MAX_PROBE_ARGS 128
  45 #define PERFPROBE_GROUP "probe"
  46
  47 #define semantic_error(msg ...) die("Semantic error :" msg)
  48
  49 /* If there is no space to write, returns -E2BIG. */
  50 static int e_snprintf(char *str, size_t size, const char *format, ...)
  51         __attribute__((format(printf, 3, 4)));
  52
  53 static int e_snprintf(char *str, size_t size, const char *format, ...)
  54 {
  55         int ret;
  56         va_list ap;
  57         va_start(ap, format);
  58         ret = vsnprintf(str, size, format, ap);
  59         va_end(ap);
  60         if (ret >= (int)size)
  61                 ret = -E2BIG;
  62         return ret;
  63 }
  64
  65 /* Check the name is good for event/group */
  66 static bool check_event_name(const char *name)
  67 {
  68         if (!isalpha(*name) && *name != '_')
  69                 return false;
  70         while (*++name != '\0') {
  71                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
  72                         return false;
  73         }
  74         return true;
  75 }
  76
  77 /* Parse probepoint definition. */
  78 static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
  79 {
  80         char *ptr, *tmp;
  81         char c, nc = 0;
  82         /*
  83          * <Syntax>
  84          * perf probe [EVENT=]SRC:LN
  85          * perf probe [EVENT=]FUNC[+OFFS|%return][@SRC]
  86          *
  87          * TODO:Group name support
  88          */
  89
  90         ptr = strchr(arg, '=');
  91         if (ptr) {      /* Event name */
  92                 *ptr = '\0';
  93                 tmp = ptr + 1;
  94                 ptr = strchr(arg, ':');
  95                 if (ptr)        /* Group name is not supported yet. */
  96                         semantic_error("Group name is not supported yet.");
  97                 if (!check_event_name(arg))
  98                         semantic_error("%s is bad for event name -it must "
  99                                        "follow C symbol-naming rule.", arg);
 100                 pp->event = strdup(arg);
 101                 arg = tmp;
 102         }
 103
 104         ptr = strpbrk(arg, ":+@%");
 105         if (ptr) {
 106                 nc = *ptr;
 107                 *ptr++ = '\0';
 108         }
 109
 110         /* Check arg is function or file and copy it */
 111         if (strchr(arg, '.'))   /* File */
 112                 pp->file = strdup(arg);
 113         else                    /* Function */
 114                 pp->function = strdup(arg);
 115         DIE_IF(pp->file == NULL && pp->function == NULL);
 116
 117         /* Parse other options */
 118         while (ptr) {
 119                 arg = ptr;
 120                 c = nc;
 121                 ptr = strpbrk(arg, ":+@%");
 122                 if (ptr) {
 123                         nc = *ptr;
 124                         *ptr++ = '\0';
 125                 }
 126                 switch (c) {
 127                 case ':':       /* Line number */
 128                         pp->line = strtoul(arg, &tmp, 0);
 129                         if (*tmp != '\0')
 130                                 semantic_error("There is non-digit charactor"
 131                                                 " in line number.");
 132                         break;
 133                 case '+':       /* Byte offset from a symbol */
 134                         pp->offset = strtoul(arg, &tmp, 0);
 135                         if (*tmp != '\0')
 136                                 semantic_error("There is non-digit charactor"
 137                                                 " in offset.");
 138                         break;
 139                 case '@':       /* File name */
 140                         if (pp->file)
 141                                 semantic_error("SRC@SRC is not allowed.");
 142                         pp->file = strdup(arg);
 143                         DIE_IF(pp->file == NULL);
 144                         if (ptr)
 145                                 semantic_error("@SRC must be the last "
 146                                                "option.");
 147                         break;
 148                 case '%':       /* Probe places */
 149                         if (strcmp(arg, "return") == 0) {
 150                                 pp->retprobe = 1;
 151                         } else  /* Others not supported yet */
 152                                 semantic_error("%%%s is not supported.", arg);
 153                         break;
 154                 default:
 155                         DIE_IF("Program has a bug.");
 156                         break;
 157                 }
 158         }
 159
 160         /* Exclusion check */
 161         if (pp->line && pp->offset)
 162                 semantic_error("Offset can't be used with line number.");
 163
 164         if (!pp->line && pp->file && !pp->function)
 165                 semantic_error("File always requires line number.");
 166
 167         if (pp->offset && !pp->function)
 168                 semantic_error("Offset requires an entry function.");
 169
 170         if (pp->retprobe && !pp->function)
 171                 semantic_error("Return probe requires an entry function.");
 172
 173         if ((pp->offset || pp->line) && pp->retprobe)
 174                 semantic_error("Offset/Line can't be used with return probe.");
 175
 176         pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
 177                  pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
 178 }
 179
 180 /* Parse perf-probe event definition */
 181 void parse_perf_probe_event(const char *str, struct probe_point *pp,
 182                             bool *need_dwarf)
 183 {
 184         char **argv;
 185         int argc, i;
 186
 187         *need_dwarf = false;
 188
 189         argv = argv_split(str, &argc);
 190         if (!argv)
 191                 die("argv_split failed.");
 192         if (argc > MAX_PROBE_ARGS + 1)
 193                 semantic_error("Too many arguments");
 194
 195         /* Parse probe point */
 196         parse_perf_probe_probepoint(argv[0], pp);
 197         if (pp->file || pp->line)
 198                 *need_dwarf = true;
 199
 200         /* Copy arguments and ensure return probe has no C argument */
 201         pp->nr_args = argc - 1;
 202         pp->args = zalloc(sizeof(char *) * pp->nr_args);
 203         for (i = 0; i < pp->nr_args; i++) {
 204                 pp->args[i] = strdup(argv[i + 1]);
 205                 if (!pp->args[i])
 206                         die("Failed to copy argument.");
 207                 if (is_c_varname(pp->args[i])) {
 208                         if (pp->retprobe)
 209                                 semantic_error("You can't specify local"
 210                                                 " variable for kretprobe");
 211                         *need_dwarf = true;
 212                 }
 213         }
 214
 215         argv_free(argv);
 216 }
 217
 218 /* Parse kprobe_events event into struct probe_point */
 219 void parse_trace_kprobe_event(const char *str, struct probe_point *pp)
 220 {
 221         char pr;
 222         char *p;
 223         int ret, i, argc;
 224         char **argv;
 225
 226         pr_debug("Parsing kprobe_events: %s\n", str);
 227         argv = argv_split(str, &argc);
 228         if (!argv)
 229                 die("argv_split failed.");
 230         if (argc < 2)
 231                 semantic_error("Too less arguments.");
 232
 233         /* Scan event and group name. */
 234         ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
 235                      &pr, (float *)(void *)&pp->group,
 236                      (float *)(void *)&pp->event);
 237         if (ret != 3)
 238                 semantic_error("Failed to parse event name: %s", argv[0]);
 239         pr_debug("Group:%s Event:%s probe:%c\n", pp->group, pp->event, pr);
 240
 241         pp->retprobe = (pr == 'r');
 242
 243         /* Scan function name and offset */
 244         ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function,
 245                      &pp->offset);
 246         if (ret == 1)
 247                 pp->offset = 0;
 248
 249         /* kprobe_events doesn't have this information */
 250         pp->line = 0;
 251         pp->file = NULL;
 252
 253         pp->nr_args = argc - 2;
 254         pp->args = zalloc(sizeof(char *) * pp->nr_args);
 255         for (i = 0; i < pp->nr_args; i++) {
 256                 p = strchr(argv[i + 2], '=');
 257                 if (p)  /* We don't need which register is assigned. */
 258                         *p = '\0';
 259                 pp->args[i] = strdup(argv[i + 2]);
 260                 if (!pp->args[i])
 261                         die("Failed to copy argument.");
 262         }
 263
 264         argv_free(argv);
 265 }
 266
 267 /* Synthesize only probe point (not argument) */
 268 int synthesize_perf_probe_point(struct probe_point *pp)
 269 {
 270         char *buf;
 271         char offs[64] = "", line[64] = "";
 272         int ret;
 273
 274         pp->probes[0] = buf = zalloc(MAX_CMDLEN);
 275         if (!buf)
 276                 die("Failed to allocate memory by zalloc.");
 277         if (pp->offset) {
 278                 ret = e_snprintf(offs, 64, "+%d", pp->offset);
 279                 if (ret <= 0)
 280                         goto error;
 281         }
 282         if (pp->line) {
 283                 ret = e_snprintf(line, 64, ":%d", pp->line);
 284                 if (ret <= 0)
 285                         goto error;
 286         }
 287
 288         if (pp->function)
 289                 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
 290                                  offs, pp->retprobe ? "%return" : "", line);
 291         else
 292                 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", pp->file, line);
 293         if (ret <= 0) {
 294 error:
 295                 free(pp->probes[0]);
 296                 pp->probes[0] = NULL;
 297         }
 298         return ret;
 299 }
 300
 301 int synthesize_perf_probe_event(struct probe_point *pp)
 302 {
 303         char *buf;
 304         int i, len, ret;
 305
 306         len = synthesize_perf_probe_point(pp);
 307         if (len < 0)
 308                 return 0;
 309
 310         buf = pp->probes[0];
 311         for (i = 0; i < pp->nr_args; i++) {
 312                 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
 313                                  pp->args[i]);
 314                 if (ret <= 0)
 315                         goto error;
 316                 len += ret;
 317         }
 318         pp->found = 1;
 319
 320         return pp->found;
 321 error:
 322         free(pp->probes[0]);
 323         pp->probes[0] = NULL;
 324
 325         return ret;
 326 }
 327
 328 int synthesize_trace_kprobe_event(struct probe_point *pp)
 329 {
 330         char *buf;
 331         int i, len, ret;
 332
 333         pp->probes[0] = buf = zalloc(MAX_CMDLEN);
 334         if (!buf)
 335                 die("Failed to allocate memory by zalloc.");
 336         ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
 337         if (ret <= 0)
 338                 goto error;
 339         len = ret;
 340
 341         for (i = 0; i < pp->nr_args; i++) {
 342                 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
 343                                  pp->args[i]);
 344                 if (ret <= 0)
 345                         goto error;
 346                 len += ret;
 347         }
 348         pp->found = 1;
 349
 350         return pp->found;
 351 error:
 352         free(pp->probes[0]);
 353         pp->probes[0] = NULL;
 354
 355         return ret;
 356 }
 357
 358 static int open_kprobe_events(int flags, int mode)
 359 {
 360         char buf[PATH_MAX];
 361         int ret;
 362
 363         ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
 364         if (ret < 0)
 365                 die("Failed to make kprobe_events path.");
 366
 367         ret = open(buf, flags, mode);
 368         if (ret < 0) {
 369                 if (errno == ENOENT)
 370                         die("kprobe_events file does not exist -"
 371                             " please rebuild with CONFIG_KPROBE_TRACER.");
 372                 else
 373                         die("Could not open kprobe_events file: %s",
 374                             strerror(errno));
 375         }
 376         return ret;
 377 }
 378
 379 /* Get raw string list of current kprobe_events */
 380 static struct strlist *get_trace_kprobe_event_rawlist(int fd)
 381 {
 382         int ret, idx;
 383         FILE *fp;
 384         char buf[MAX_CMDLEN];
 385         char *p;
 386         struct strlist *sl;
 387
 388         sl = strlist__new(true, NULL);
 389
 390         fp = fdopen(dup(fd), "r");
 391         while (!feof(fp)) {
 392                 p = fgets(buf, MAX_CMDLEN, fp);
 393                 if (!p)
 394                         break;
 395
 396                 idx = strlen(p) - 1;
 397                 if (p[idx] == '\n')
 398                         p[idx] = '\0';
 399                 ret = strlist__add(sl, buf);
 400                 if (ret < 0)
 401                         die("strlist__add failed: %s", strerror(-ret));
 402         }
 403         fclose(fp);
 404
 405         return sl;
 406 }
 407
 408 /* Free and zero clear probe_point */
 409 static void clear_probe_point(struct probe_point *pp)
 410 {
 411         int i;
 412
 413         if (pp->event)
 414                 free(pp->event);
 415         if (pp->group)
 416                 free(pp->group);
 417         if (pp->function)
 418                 free(pp->function);
 419         if (pp->file)
 420                 free(pp->file);
 421         for (i = 0; i < pp->nr_args; i++)
 422                 free(pp->args[i]);
 423         if (pp->args)
 424                 free(pp->args);
 425         for (i = 0; i < pp->found; i++)
 426                 free(pp->probes[i]);
 427         memset(pp, 0, sizeof(*pp));
 428 }
 429
 430 /* Show an event */
 431 static void show_perf_probe_event(const char *event, const char *place,
 432                                   struct probe_point *pp)
 433 {
 434         int i, ret;
 435         char buf[128];
 436
 437         ret = e_snprintf(buf, 128, "%s:%s", pp->group, event);
 438         if (ret < 0)
 439                 die("Failed to copy event: %s", strerror(-ret));
 440         printf("  %-40s (on %s", buf, place);
 441
 442         if (pp->nr_args > 0) {
 443                 printf(" with");
 444                 for (i = 0; i < pp->nr_args; i++)
 445                         printf(" %s", pp->args[i]);
 446         }
 447         printf(")\n");
 448 }
 449
 450 /* List up current perf-probe events */
 451 void show_perf_probe_events(void)
 452 {
 453         int fd;
 454         struct probe_point pp;
 455         struct strlist *rawlist;
 456         struct str_node *ent;
 457
 458         fd = open_kprobe_events(O_RDONLY, 0);
 459         rawlist = get_trace_kprobe_event_rawlist(fd);
 460         close(fd);
 461
 462         strlist__for_each(ent, rawlist) {
 463                 parse_trace_kprobe_event(ent->s, &pp);
 464                 /* Synthesize only event probe point */
 465                 synthesize_perf_probe_point(&pp);
 466                 /* Show an event */
 467                 show_perf_probe_event(pp.event, pp.probes[0], &pp);
 468                 clear_probe_point(&pp);
 469         }
 470
 471         strlist__delete(rawlist);
 472 }
 473
 474 /* Get current perf-probe event names */
 475 static struct strlist *get_perf_event_names(int fd, bool include_group)
 476 {
 477         char buf[128];
 478         struct strlist *sl, *rawlist;
 479         struct str_node *ent;
 480         struct probe_point pp;
 481
 482         memset(&pp, 0, sizeof(pp));
 483         rawlist = get_trace_kprobe_event_rawlist(fd);
 484
 485         sl = strlist__new(true, NULL);
 486         strlist__for_each(ent, rawlist) {
 487                 parse_trace_kprobe_event(ent->s, &pp);
 488                 if (include_group) {
 489                         if (e_snprintf(buf, 128, "%s:%s", pp.group,
 490                                        pp.event) < 0)
 491                                 die("Failed to copy group:event name.");
 492                         strlist__add(sl, buf);
 493                 } else
 494                         strlist__add(sl, pp.event);
 495                 clear_probe_point(&pp);
 496         }
 497
 498         strlist__delete(rawlist);
 499
 500         return sl;
 501 }
 502
 503 static void write_trace_kprobe_event(int fd, const char *buf)
 504 {
 505         int ret;
 506
 507         pr_debug("Writing event: %s\n", buf);
 508         ret = write(fd, buf, strlen(buf));
 509         if (ret <= 0)
 510                 die("Failed to write event: %s", strerror(errno));
 511 }
 512
 513 static void get_new_event_name(char *buf, size_t len, const char *base,
 514                                struct strlist *namelist, bool allow_suffix)
 515 {
 516         int i, ret;
 517
 518         /* Try no suffix */
 519         ret = e_snprintf(buf, len, "%s", base);
 520         if (ret < 0)
 521                 die("snprintf() failed: %s", strerror(-ret));
 522         if (!strlist__has_entry(namelist, buf))
 523                 return;
 524
 525         if (!allow_suffix) {
 526                 pr_warning("Error: event \"%s\" already exists. "
 527                            "(Use -f to force duplicates.)\n", base);
 528                 die("Can't add new event.");
 529         }
 530
 531         /* Try to add suffix */
 532         for (i = 1; i < MAX_EVENT_INDEX; i++) {
 533                 ret = e_snprintf(buf, len, "%s_%d", base, i);
 534                 if (ret < 0)
 535                         die("snprintf() failed: %s", strerror(-ret));
 536                 if (!strlist__has_entry(namelist, buf))
 537                         break;
 538         }
 539         if (i == MAX_EVENT_INDEX)
 540                 die("Too many events are on the same function.");
 541 }
 542
 543 void add_trace_kprobe_events(struct probe_point *probes, int nr_probes,
 544                              bool force_add)
 545 {
 546         int i, j, fd;
 547         struct probe_point *pp;
 548         char buf[MAX_CMDLEN];
 549         char event[64];
 550         struct strlist *namelist;
 551         bool allow_suffix;
 552
 553         fd = open_kprobe_events(O_RDWR, O_APPEND);
 554         /* Get current event names */
 555         namelist = get_perf_event_names(fd, false);
 556
 557         for (j = 0; j < nr_probes; j++) {
 558                 pp = probes + j;
 559                 if (!pp->event)
 560                         pp->event = strdup(pp->function);
 561                 if (!pp->group)
 562                         pp->group = strdup(PERFPROBE_GROUP);
 563                 DIE_IF(!pp->event || !pp->group);
 564                 /* If force_add is true, suffix search is allowed */
 565                 allow_suffix = force_add;
 566                 for (i = 0; i < pp->found; i++) {
 567                         /* Get an unused new event name */
 568                         get_new_event_name(event, 64, pp->event, namelist,
 569                                            allow_suffix);
 570                         snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
 571                                  pp->retprobe ? 'r' : 'p',
 572                                  pp->group, event,
 573                                  pp->probes[i]);
 574                         write_trace_kprobe_event(fd, buf);
 575                         printf("Added new event:\n");
 576                         /* Get the first parameter (probe-point) */
 577                         sscanf(pp->probes[i], "%s", buf);
 578                         show_perf_probe_event(event, buf, pp);
 579                         /* Add added event name to namelist */
 580                         strlist__add(namelist, event);
 581                         /*
 582                          * Probes after the first probe which comes from same
 583                          * user input are always allowed to add suffix, because
 584                          * there might be several addresses corresponding to
 585                          * one code line.
 586                          */
 587                         allow_suffix = true;
 588                 }
 589         }
 590         /* Show how to use the event. */
 591         printf("\nYou can now use it on all perf tools, such as:\n\n");
 592         printf("\tperf record -e %s:%s -a sleep 1\n\n", PERFPROBE_GROUP, event);
 593
 594         strlist__delete(namelist);
 595         close(fd);
 596 }
 597
 598 static void __del_trace_kprobe_event(int fd, struct str_node *ent)
 599 {
 600         char *p;
 601         char buf[128];
 602
 603         /* Convert from perf-probe event to trace-kprobe event */
 604         if (e_snprintf(buf, 128, "-:%s", ent->s) < 0)
 605                 die("Failed to copy event.");
 606         p = strchr(buf + 2, ':');
 607         if (!p)
 608                 die("Internal error: %s should have ':' but not.", ent->s);
 609         *p = '/';
 610
 611         write_trace_kprobe_event(fd, buf);
 612         printf("Remove event: %s\n", ent->s);
 613 }
 614
 615 static void del_trace_kprobe_event(int fd, const char *group,
 616                                    const char *event, struct strlist *namelist)
 617 {
 618         char buf[128];
 619         struct str_node *ent, *n;
 620         int found = 0;
 621
 622         if (e_snprintf(buf, 128, "%s:%s", group, event) < 0)
 623                 die("Failed to copy event.");
 624
 625         if (strpbrk(buf, "*?")) { /* Glob-exp */
 626                 strlist__for_each_safe(ent, n, namelist)
 627                         if (strglobmatch(ent->s, buf)) {
 628                                 found++;
 629                                 __del_trace_kprobe_event(fd, ent);
 630                                 strlist__remove(namelist, ent);
 631                         }
 632         } else {
 633                 ent = strlist__find(namelist, buf);
 634                 if (ent) {
 635                         found++;
 636                         __del_trace_kprobe_event(fd, ent);
 637                         strlist__remove(namelist, ent);
 638                 }
 639         }
 640         if (found == 0)
 641                 pr_info("Info: event \"%s\" does not exist, could not remove it.\n", buf);
 642 }
 643
 644 void del_trace_kprobe_events(struct strlist *dellist)
 645 {
 646         int fd;
 647         const char *group, *event;
 648         char *p, *str;
 649         struct str_node *ent;
 650         struct strlist *namelist;
 651
 652         fd = open_kprobe_events(O_RDWR, O_APPEND);
 653         /* Get current event names */
 654         namelist = get_perf_event_names(fd, true);
 655
 656         strlist__for_each(ent, dellist) {
 657                 str = strdup(ent->s);
 658                 if (!str)
 659                         die("Failed to copy event.");
 660                 pr_debug("Parsing: %s\n", str);
 661                 p = strchr(str, ':');
 662                 if (p) {
 663                         group = str;
 664                         *p = '\0';
 665                         event = p + 1;
 666                 } else {
 667                         group = "*";
 668                         event = str;
 669                 }
 670                 pr_debug("Group: %s, Event: %s\n", group, event);
 671                 del_trace_kprobe_event(fd, group, event, namelist);
 672                 free(str);
 673         }
 674         strlist__delete(namelist);
 675         close(fd);
 676 }
 677