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 /* Parse probepoint definition. */
  66 static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
  67 {
  68         char *ptr, *tmp;
  69         char c, nc = 0;
  70         /*
  71          * <Syntax>
  72          * perf probe SRC:LN
  73          * perf probe FUNC[+OFFS|%return][@SRC]
  74          */
  75
  76         ptr = strpbrk(arg, ":+@%");
  77         if (ptr) {
  78                 nc = *ptr;
  79                 *ptr++ = '\0';
  80         }
  81
  82         /* Check arg is function or file and copy it */
  83         if (strchr(arg, '.'))   /* File */
  84                 pp->file = strdup(arg);
  85         else                    /* Function */
  86                 pp->function = strdup(arg);
  87         DIE_IF(pp->file == NULL && pp->function == NULL);
  88
  89         /* Parse other options */
  90         while (ptr) {
  91                 arg = ptr;
  92                 c = nc;
  93                 ptr = strpbrk(arg, ":+@%");
  94                 if (ptr) {
  95                         nc = *ptr;
  96                         *ptr++ = '\0';
  97                 }
  98                 switch (c) {
  99                 case ':':       /* Line number */
 100                         pp->line = strtoul(arg, &tmp, 0);
 101                         if (*tmp != '\0')
 102                                 semantic_error("There is non-digit charactor"
 103                                                 " in line number.");
 104                         break;
 105                 case '+':       /* Byte offset from a symbol */
 106                         pp->offset = strtoul(arg, &tmp, 0);
 107                         if (*tmp != '\0')
 108                                 semantic_error("There is non-digit charactor"
 109                                                 " in offset.");
 110                         break;
 111                 case '@':       /* File name */
 112                         if (pp->file)
 113                                 semantic_error("SRC@SRC is not allowed.");
 114                         pp->file = strdup(arg);
 115                         DIE_IF(pp->file == NULL);
 116                         if (ptr)
 117                                 semantic_error("@SRC must be the last "
 118                                                "option.");
 119                         break;
 120                 case '%':       /* Probe places */
 121                         if (strcmp(arg, "return") == 0) {
 122                                 pp->retprobe = 1;
 123                         } else  /* Others not supported yet */
 124                                 semantic_error("%%%s is not supported.", arg);
 125                         break;
 126                 default:
 127                         DIE_IF("Program has a bug.");
 128                         break;
 129                 }
 130         }
 131
 132         /* Exclusion check */
 133         if (pp->line && pp->offset)
 134                 semantic_error("Offset can't be used with line number.");
 135
 136         if (!pp->line && pp->file && !pp->function)
 137                 semantic_error("File always requires line number.");
 138
 139         if (pp->offset && !pp->function)
 140                 semantic_error("Offset requires an entry function.");
 141
 142         if (pp->retprobe && !pp->function)
 143                 semantic_error("Return probe requires an entry function.");
 144
 145         if ((pp->offset || pp->line) && pp->retprobe)
 146                 semantic_error("Offset/Line can't be used with return probe.");
 147
 148         pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
 149                  pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
 150 }
 151
 152 /* Parse perf-probe event definition */
 153 int parse_perf_probe_event(const char *str, struct probe_point *pp)
 154 {
 155         char **argv;
 156         int argc, i, need_dwarf = 0;
 157
 158         argv = argv_split(str, &argc);
 159         if (!argv)
 160                 die("argv_split failed.");
 161         if (argc > MAX_PROBE_ARGS + 1)
 162                 semantic_error("Too many arguments");
 163
 164         /* Parse probe point */
 165         parse_perf_probe_probepoint(argv[0], pp);
 166         if (pp->file || pp->line)
 167                 need_dwarf = 1;
 168
 169         /* Copy arguments and ensure return probe has no C argument */
 170         pp->nr_args = argc - 1;
 171         pp->args = zalloc(sizeof(char *) * pp->nr_args);
 172         for (i = 0; i < pp->nr_args; i++) {
 173                 pp->args[i] = strdup(argv[i + 1]);
 174                 if (!pp->args[i])
 175                         die("Failed to copy argument.");
 176                 if (is_c_varname(pp->args[i])) {
 177                         if (pp->retprobe)
 178                                 semantic_error("You can't specify local"
 179                                                 " variable for kretprobe");
 180                         need_dwarf = 1;
 181                 }
 182         }
 183
 184         argv_free(argv);
 185         return need_dwarf;
 186 }
 187
 188 /* Parse kprobe_events event into struct probe_point */
 189 void parse_trace_kprobe_event(const char *str, char **group, char **event,
 190                               struct probe_point *pp)
 191 {
 192         char pr;
 193         char *p;
 194         int ret, i, argc;
 195         char **argv;
 196
 197         pr_debug("Parsing kprobe_events: %s\n", str);
 198         argv = argv_split(str, &argc);
 199         if (!argv)
 200                 die("argv_split failed.");
 201         if (argc < 2)
 202                 semantic_error("Too less arguments.");
 203
 204         /* Scan event and group name. */
 205         ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
 206                      &pr, (float *)(void *)group, (float *)(void *)event);
 207         if (ret != 3)
 208                 semantic_error("Failed to parse event name: %s", argv[0]);
 209         pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr);
 210
 211         if (!pp)
 212                 goto end;
 213
 214         pp->retprobe = (pr == 'r');
 215
 216         /* Scan function name and offset */
 217         ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function, &pp->offset);
 218         if (ret == 1)
 219                 pp->offset = 0;
 220
 221         /* kprobe_events doesn't have this information */
 222         pp->line = 0;
 223         pp->file = NULL;
 224
 225         pp->nr_args = argc - 2;
 226         pp->args = zalloc(sizeof(char *) * pp->nr_args);
 227         for (i = 0; i < pp->nr_args; i++) {
 228                 p = strchr(argv[i + 2], '=');
 229                 if (p)  /* We don't need which register is assigned. */
 230                         *p = '\0';
 231                 pp->args[i] = strdup(argv[i + 2]);
 232                 if (!pp->args[i])
 233                         die("Failed to copy argument.");
 234         }
 235
 236 end:
 237         argv_free(argv);
 238 }
 239
 240 int synthesize_perf_probe_event(struct probe_point *pp)
 241 {
 242         char *buf;
 243         char offs[64] = "", line[64] = "";
 244         int i, len, ret;
 245
 246         pp->probes[0] = buf = zalloc(MAX_CMDLEN);
 247         if (!buf)
 248                 die("Failed to allocate memory by zalloc.");
 249         if (pp->offset) {
 250                 ret = e_snprintf(offs, 64, "+%d", pp->offset);
 251                 if (ret <= 0)
 252                         goto error;
 253         }
 254         if (pp->line) {
 255                 ret = e_snprintf(line, 64, ":%d", pp->line);
 256                 if (ret <= 0)
 257                         goto error;
 258         }
 259
 260         if (pp->function)
 261                 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
 262                                  offs, pp->retprobe ? "%return" : "", line);
 263         else
 264                 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", pp->file, line);
 265         if (ret <= 0)
 266                 goto error;
 267         len = ret;
 268
 269         for (i = 0; i < pp->nr_args; i++) {
 270                 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
 271                                  pp->args[i]);
 272                 if (ret <= 0)
 273                         goto error;
 274                 len += ret;
 275         }
 276         pp->found = 1;
 277
 278         return pp->found;
 279 error:
 280         free(pp->probes[0]);
 281
 282         return ret;
 283 }
 284
 285 int synthesize_trace_kprobe_event(struct probe_point *pp)
 286 {
 287         char *buf;
 288         int i, len, ret;
 289
 290         pp->probes[0] = buf = zalloc(MAX_CMDLEN);
 291         if (!buf)
 292                 die("Failed to allocate memory by zalloc.");
 293         ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
 294         if (ret <= 0)
 295                 goto error;
 296         len = ret;
 297
 298         for (i = 0; i < pp->nr_args; i++) {
 299                 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
 300                                  pp->args[i]);
 301                 if (ret <= 0)
 302                         goto error;
 303                 len += ret;
 304         }
 305         pp->found = 1;
 306
 307         return pp->found;
 308 error:
 309         free(pp->probes[0]);
 310
 311         return ret;
 312 }
 313
 314 static int open_kprobe_events(int flags, int mode)
 315 {
 316         char buf[PATH_MAX];
 317         int ret;
 318
 319         ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
 320         if (ret < 0)
 321                 die("Failed to make kprobe_events path.");
 322
 323         ret = open(buf, flags, mode);
 324         if (ret < 0) {
 325                 if (errno == ENOENT)
 326                         die("kprobe_events file does not exist -"
 327                             " please rebuild with CONFIG_KPROBE_TRACER.");
 328                 else
 329                         die("Could not open kprobe_events file: %s",
 330                             strerror(errno));
 331         }
 332         return ret;
 333 }
 334
 335 /* Get raw string list of current kprobe_events */
 336 static struct strlist *get_trace_kprobe_event_rawlist(int fd)
 337 {
 338         int ret, idx;
 339         FILE *fp;
 340         char buf[MAX_CMDLEN];
 341         char *p;
 342         struct strlist *sl;
 343
 344         sl = strlist__new(true, NULL);
 345
 346         fp = fdopen(dup(fd), "r");
 347         while (!feof(fp)) {
 348                 p = fgets(buf, MAX_CMDLEN, fp);
 349                 if (!p)
 350                         break;
 351
 352                 idx = strlen(p) - 1;
 353                 if (p[idx] == '\n')
 354                         p[idx] = '\0';
 355                 ret = strlist__add(sl, buf);
 356                 if (ret < 0)
 357                         die("strlist__add failed: %s", strerror(-ret));
 358         }
 359         fclose(fp);
 360
 361         return sl;
 362 }
 363
 364 /* Free and zero clear probe_point */
 365 static void clear_probe_point(struct probe_point *pp)
 366 {
 367         int i;
 368
 369         if (pp->function)
 370                 free(pp->function);
 371         if (pp->file)
 372                 free(pp->file);
 373         for (i = 0; i < pp->nr_args; i++)
 374                 free(pp->args[i]);
 375         if (pp->args)
 376                 free(pp->args);
 377         for (i = 0; i < pp->found; i++)
 378                 free(pp->probes[i]);
 379         memset(pp, 0, sizeof(*pp));
 380 }
 381
 382 /* Show an event */
 383 static void show_perf_probe_event(const char *group, const char *event,
 384                                   const char *place, struct probe_point *pp)
 385 {
 386         int i;
 387         char buf[128];
 388
 389         e_snprintf(buf, 128, "%s:%s", group, event);
 390         printf("  %-40s (on %s", buf, place);
 391
 392         if (pp->nr_args > 0) {
 393                 printf(" with");
 394                 for (i = 0; i < pp->nr_args; i++)
 395                         printf(" %s", pp->args[i]);
 396         }
 397         printf(")\n");
 398 }
 399
 400 /* List up current perf-probe events */
 401 void show_perf_probe_events(void)
 402 {
 403         unsigned int i;
 404         int fd, nr;
 405         char *group, *event;
 406         struct probe_point pp;
 407         struct strlist *rawlist;
 408         struct str_node *ent;
 409
 410         fd = open_kprobe_events(O_RDONLY, 0);
 411         rawlist = get_trace_kprobe_event_rawlist(fd);
 412         close(fd);
 413
 414         for (i = 0; i < strlist__nr_entries(rawlist); i++) {
 415                 ent = strlist__entry(rawlist, i);
 416                 parse_trace_kprobe_event(ent->s, &group, &event, &pp);
 417                 /* Synthesize only event probe point */
 418                 nr = pp.nr_args;
 419                 pp.nr_args = 0;
 420                 synthesize_perf_probe_event(&pp);
 421                 pp.nr_args = nr;
 422                 /* Show an event */
 423                 show_perf_probe_event(group, event, pp.probes[0], &pp);
 424                 free(group);
 425                 free(event);
 426                 clear_probe_point(&pp);
 427         }
 428
 429         strlist__delete(rawlist);
 430 }
 431
 432 /* Get current perf-probe event names */
 433 static struct strlist *get_perf_event_names(int fd, bool include_group)
 434 {
 435         unsigned int i;
 436         char *group, *event;
 437         char buf[128];
 438         struct strlist *sl, *rawlist;
 439         struct str_node *ent;
 440
 441         rawlist = get_trace_kprobe_event_rawlist(fd);
 442
 443         sl = strlist__new(true, NULL);
 444         for (i = 0; i < strlist__nr_entries(rawlist); i++) {
 445                 ent = strlist__entry(rawlist, i);
 446                 parse_trace_kprobe_event(ent->s, &group, &event, NULL);
 447                 if (include_group) {
 448                         if (e_snprintf(buf, 128, "%s:%s", group, event) < 0)
 449                                 die("Failed to copy group:event name.");
 450                         strlist__add(sl, buf);
 451                 } else
 452                         strlist__add(sl, event);
 453                 free(group);
 454                 free(event);
 455         }
 456
 457         strlist__delete(rawlist);
 458
 459         return sl;
 460 }
 461
 462 static void write_trace_kprobe_event(int fd, const char *buf)
 463 {
 464         int ret;
 465
 466         pr_debug("Writing event: %s\n", buf);
 467         ret = write(fd, buf, strlen(buf));
 468         if (ret <= 0)
 469                 die("Failed to write event: %s", strerror(errno));
 470 }
 471
 472 static void get_new_event_name(char *buf, size_t len, const char *base,
 473                                struct strlist *namelist)
 474 {
 475         int i, ret;
 476
 477         /* Try no suffix */
 478         ret = e_snprintf(buf, len, "%s", base);
 479         if (ret < 0)
 480                 die("snprintf() failed: %s", strerror(-ret));
 481         if (!strlist__has_entry(namelist, buf))
 482                 return;
 483
 484         /* Try to add suffix */
 485         for (i = 1; i < MAX_EVENT_INDEX; i++) {
 486                 ret = e_snprintf(buf, len, "%s_%d", base, i);
 487                 if (ret < 0)
 488                         die("snprintf() failed: %s", strerror(-ret));
 489                 if (!strlist__has_entry(namelist, buf))
 490                         break;
 491         }
 492         if (i == MAX_EVENT_INDEX)
 493                 die("Too many events are on the same function.");
 494 }
 495
 496 void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
 497 {
 498         int i, j, fd;
 499         struct probe_point *pp;
 500         char buf[MAX_CMDLEN];
 501         char event[64];
 502         struct strlist *namelist;
 503
 504         fd = open_kprobe_events(O_RDWR, O_APPEND);
 505         /* Get current event names */
 506         namelist = get_perf_event_names(fd, false);
 507
 508         for (j = 0; j < nr_probes; j++) {
 509                 pp = probes + j;
 510                 for (i = 0; i < pp->found; i++) {
 511                         /* Get an unused new event name */
 512                         get_new_event_name(event, 64, pp->function, namelist);
 513                         snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
 514                                  pp->retprobe ? 'r' : 'p',
 515                                  PERFPROBE_GROUP, event,
 516                                  pp->probes[i]);
 517                         write_trace_kprobe_event(fd, buf);
 518                         printf("Added new event:\n");
 519                         /* Get the first parameter (probe-point) */
 520                         sscanf(pp->probes[i], "%s", buf);
 521                         show_perf_probe_event(PERFPROBE_GROUP, event,
 522                                               buf, pp);
 523                         /* Add added event name to namelist */
 524                         strlist__add(namelist, event);
 525                 }
 526         }
 527         /* Show how to use the event. */
 528         printf("\nYou can now use it on all perf tools, such as:\n\n");
 529         printf("\tperf record -e %s:%s -a sleep 1\n\n", PERFPROBE_GROUP, event);
 530
 531         strlist__delete(namelist);
 532         close(fd);
 533 }
 534
 535 static void del_trace_kprobe_event(int fd, const char *group,
 536                                    const char *event, struct strlist *namelist)
 537 {
 538         char buf[128];
 539
 540         if (e_snprintf(buf, 128, "%s:%s", group, event) < 0)
 541                 die("Failed to copy event.");
 542         if (!strlist__has_entry(namelist, buf)) {
 543                 pr_warning("Warning: event \"%s\" is not found.\n", buf);
 544                 return;
 545         }
 546         /* Convert from perf-probe event to trace-kprobe event */
 547         if (e_snprintf(buf, 128, "-:%s/%s", group, event) < 0)
 548                 die("Failed to copy event.");
 549
 550         write_trace_kprobe_event(fd, buf);
 551         printf("Remove event: %s:%s\n", group, event);
 552 }
 553
 554 void del_trace_kprobe_events(struct strlist *dellist)
 555 {
 556         int fd;
 557         unsigned int i;
 558         const char *group, *event;
 559         char *p, *str;
 560         struct str_node *ent;
 561         struct strlist *namelist;
 562
 563         fd = open_kprobe_events(O_RDWR, O_APPEND);
 564         /* Get current event names */
 565         namelist = get_perf_event_names(fd, true);
 566
 567         for (i = 0; i < strlist__nr_entries(dellist); i++) {
 568                 ent = strlist__entry(dellist, i);
 569                 str = strdup(ent->s);
 570                 if (!str)
 571                         die("Failed to copy event.");
 572                 p = strchr(str, ':');
 573                 if (p) {
 574                         group = str;
 575                         *p = '\0';
 576                         event = p + 1;
 577                 } else {
 578                         group = PERFPROBE_GROUP;
 579                         event = str;
 580                 }
 581                 del_trace_kprobe_event(fd, group, event, namelist);
 582                 free(str);
 583         }
 584         strlist__delete(namelist);
 585         close(fd);
 586 }
 587