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 pp->found = 1; 276 if (!buf) 277 die("Failed to allocate memory by zalloc."); 278 if (pp->offset) { 279 ret = e_snprintf(offs, 64, "+%d", pp->offset); 280 if (ret <= 0) 281 goto error; 282 } 283 if (pp->line) { 284 ret = e_snprintf(line, 64, ":%d", pp->line); 285 if (ret <= 0) 286 goto error; 287 } 288 289 if (pp->function) 290 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function, 291 offs, pp->retprobe ? "%return" : "", line); 292 else 293 ret = e_snprintf(buf, MAX_CMDLEN, "%s%s", pp->file, line); 294 if (ret <= 0) { 295 error: 296 free(pp->probes[0]); 297 pp->probes[0] = NULL; 298 pp->found = 0; 299 } 300 return ret; 301 } 302 303 int synthesize_perf_probe_event(struct probe_point *pp) 304 { 305 char *buf; 306 int i, len, ret; 307 308 len = synthesize_perf_probe_point(pp); 309 if (len < 0) 310 return 0; 311 312 buf = pp->probes[0]; 313 for (i = 0; i < pp->nr_args; i++) { 314 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s", 315 pp->args[i]); 316 if (ret <= 0) 317 goto error; 318 len += ret; 319 } 320 pp->found = 1; 321 322 return pp->found; 323 error: 324 free(pp->probes[0]); 325 pp->probes[0] = NULL; 326 327 return ret; 328 } 329 330 int synthesize_trace_kprobe_event(struct probe_point *pp) 331 { 332 char *buf; 333 int i, len, ret; 334 335 pp->probes[0] = buf = zalloc(MAX_CMDLEN); 336 if (!buf) 337 die("Failed to allocate memory by zalloc."); 338 ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset); 339 if (ret <= 0) 340 goto error; 341 len = ret; 342 343 for (i = 0; i < pp->nr_args; i++) { 344 ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s", 345 pp->args[i]); 346 if (ret <= 0) 347 goto error; 348 len += ret; 349 } 350 pp->found = 1; 351 352 return pp->found; 353 error: 354 free(pp->probes[0]); 355 pp->probes[0] = NULL; 356 357 return ret; 358 } 359 360 static int open_kprobe_events(int flags, int mode) 361 { 362 char buf[PATH_MAX]; 363 int ret; 364 365 ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path); 366 if (ret < 0) 367 die("Failed to make kprobe_events path."); 368 369 ret = open(buf, flags, mode); 370 if (ret < 0) { 371 if (errno == ENOENT) 372 die("kprobe_events file does not exist -" 373 " please rebuild with CONFIG_KPROBE_TRACER."); 374 else 375 die("Could not open kprobe_events file: %s", 376 strerror(errno)); 377 } 378 return ret; 379 } 380 381 /* Get raw string list of current kprobe_events */ 382 static struct strlist *get_trace_kprobe_event_rawlist(int fd) 383 { 384 int ret, idx; 385 FILE *fp; 386 char buf[MAX_CMDLEN]; 387 char *p; 388 struct strlist *sl; 389 390 sl = strlist__new(true, NULL); 391 392 fp = fdopen(dup(fd), "r"); 393 while (!feof(fp)) { 394 p = fgets(buf, MAX_CMDLEN, fp); 395 if (!p) 396 break; 397 398 idx = strlen(p) - 1; 399 if (p[idx] == '\n') 400 p[idx] = '\0'; 401 ret = strlist__add(sl, buf); 402 if (ret < 0) 403 die("strlist__add failed: %s", strerror(-ret)); 404 } 405 fclose(fp); 406 407 return sl; 408 } 409 410 /* Free and zero clear probe_point */ 411 static void clear_probe_point(struct probe_point *pp) 412 { 413 int i; 414 415 if (pp->event) 416 free(pp->event); 417 if (pp->group) 418 free(pp->group); 419 if (pp->function) 420 free(pp->function); 421 if (pp->file) 422 free(pp->file); 423 for (i = 0; i < pp->nr_args; i++) 424 free(pp->args[i]); 425 if (pp->args) 426 free(pp->args); 427 for (i = 0; i < pp->found; i++) 428 free(pp->probes[i]); 429 memset(pp, 0, sizeof(*pp)); 430 } 431 432 /* Show an event */ 433 static void show_perf_probe_event(const char *event, const char *place, 434 struct probe_point *pp) 435 { 436 int i, ret; 437 char buf[128]; 438 439 ret = e_snprintf(buf, 128, "%s:%s", pp->group, event); 440 if (ret < 0) 441 die("Failed to copy event: %s", strerror(-ret)); 442 printf(" %-40s (on %s", buf, place); 443 444 if (pp->nr_args > 0) { 445 printf(" with"); 446 for (i = 0; i < pp->nr_args; i++) 447 printf(" %s", pp->args[i]); 448 } 449 printf(")\n"); 450 } 451 452 /* List up current perf-probe events */ 453 void show_perf_probe_events(void) 454 { 455 int fd; 456 struct probe_point pp; 457 struct strlist *rawlist; 458 struct str_node *ent; 459 460 memset(&pp, 0, sizeof(pp)); 461 fd = open_kprobe_events(O_RDONLY, 0); 462 rawlist = get_trace_kprobe_event_rawlist(fd); 463 close(fd); 464 465 strlist__for_each(ent, rawlist) { 466 parse_trace_kprobe_event(ent->s, &pp); 467 /* Synthesize only event probe point */ 468 synthesize_perf_probe_point(&pp); 469 /* Show an event */ 470 show_perf_probe_event(pp.event, pp.probes[0], &pp); 471 clear_probe_point(&pp); 472 } 473 474 strlist__delete(rawlist); 475 } 476 477 /* Get current perf-probe event names */ 478 static struct strlist *get_perf_event_names(int fd, bool include_group) 479 { 480 char buf[128]; 481 struct strlist *sl, *rawlist; 482 struct str_node *ent; 483 struct probe_point pp; 484 485 memset(&pp, 0, sizeof(pp)); 486 rawlist = get_trace_kprobe_event_rawlist(fd); 487 488 sl = strlist__new(true, NULL); 489 strlist__for_each(ent, rawlist) { 490 parse_trace_kprobe_event(ent->s, &pp); 491 if (include_group) { 492 if (e_snprintf(buf, 128, "%s:%s", pp.group, 493 pp.event) < 0) 494 die("Failed to copy group:event name."); 495 strlist__add(sl, buf); 496 } else 497 strlist__add(sl, pp.event); 498 clear_probe_point(&pp); 499 } 500 501 strlist__delete(rawlist); 502 503 return sl; 504 } 505 506 static void write_trace_kprobe_event(int fd, const char *buf) 507 { 508 int ret; 509 510 pr_debug("Writing event: %s\n", buf); 511 ret = write(fd, buf, strlen(buf)); 512 if (ret <= 0) 513 die("Failed to write event: %s", strerror(errno)); 514 } 515 516 static void get_new_event_name(char *buf, size_t len, const char *base, 517 struct strlist *namelist, bool allow_suffix) 518 { 519 int i, ret; 520 521 /* Try no suffix */ 522 ret = e_snprintf(buf, len, "%s", base); 523 if (ret < 0) 524 die("snprintf() failed: %s", strerror(-ret)); 525 if (!strlist__has_entry(namelist, buf)) 526 return; 527 528 if (!allow_suffix) { 529 pr_warning("Error: event \"%s\" already exists. " 530 "(Use -f to force duplicates.)\n", base); 531 die("Can't add new event."); 532 } 533 534 /* Try to add suffix */ 535 for (i = 1; i < MAX_EVENT_INDEX; i++) { 536 ret = e_snprintf(buf, len, "%s_%d", base, i); 537 if (ret < 0) 538 die("snprintf() failed: %s", strerror(-ret)); 539 if (!strlist__has_entry(namelist, buf)) 540 break; 541 } 542 if (i == MAX_EVENT_INDEX) 543 die("Too many events are on the same function."); 544 } 545 546 void add_trace_kprobe_events(struct probe_point *probes, int nr_probes, 547 bool force_add) 548 { 549 int i, j, fd; 550 struct probe_point *pp; 551 char buf[MAX_CMDLEN]; 552 char event[64]; 553 struct strlist *namelist; 554 bool allow_suffix; 555 556 fd = open_kprobe_events(O_RDWR, O_APPEND); 557 /* Get current event names */ 558 namelist = get_perf_event_names(fd, false); 559 560 for (j = 0; j < nr_probes; j++) { 561 pp = probes + j; 562 if (!pp->event) 563 pp->event = strdup(pp->function); 564 if (!pp->group) 565 pp->group = strdup(PERFPROBE_GROUP); 566 DIE_IF(!pp->event || !pp->group); 567 /* If force_add is true, suffix search is allowed */ 568 allow_suffix = force_add; 569 for (i = 0; i < pp->found; i++) { 570 /* Get an unused new event name */ 571 get_new_event_name(event, 64, pp->event, namelist, 572 allow_suffix); 573 snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n", 574 pp->retprobe ? 'r' : 'p', 575 pp->group, event, 576 pp->probes[i]); 577 write_trace_kprobe_event(fd, buf); 578 printf("Added new event:\n"); 579 /* Get the first parameter (probe-point) */ 580 sscanf(pp->probes[i], "%s", buf); 581 show_perf_probe_event(event, buf, pp); 582 /* Add added event name to namelist */ 583 strlist__add(namelist, event); 584 /* 585 * Probes after the first probe which comes from same 586 * user input are always allowed to add suffix, because 587 * there might be several addresses corresponding to 588 * one code line. 589 */ 590 allow_suffix = true; 591 } 592 } 593 /* Show how to use the event. */ 594 printf("\nYou can now use it on all perf tools, such as:\n\n"); 595 printf("\tperf record -e %s:%s -a sleep 1\n\n", PERFPROBE_GROUP, event); 596 597 strlist__delete(namelist); 598 close(fd); 599 } 600 601 static void __del_trace_kprobe_event(int fd, struct str_node *ent) 602 { 603 char *p; 604 char buf[128]; 605 606 /* Convert from perf-probe event to trace-kprobe event */ 607 if (e_snprintf(buf, 128, "-:%s", ent->s) < 0) 608 die("Failed to copy event."); 609 p = strchr(buf + 2, ':'); 610 if (!p) 611 die("Internal error: %s should have ':' but not.", ent->s); 612 *p = '/'; 613 614 write_trace_kprobe_event(fd, buf); 615 printf("Remove event: %s\n", ent->s); 616 } 617 618 static void del_trace_kprobe_event(int fd, const char *group, 619 const char *event, struct strlist *namelist) 620 { 621 char buf[128]; 622 struct str_node *ent, *n; 623 int found = 0; 624 625 if (e_snprintf(buf, 128, "%s:%s", group, event) < 0) 626 die("Failed to copy event."); 627 628 if (strpbrk(buf, "*?")) { /* Glob-exp */ 629 strlist__for_each_safe(ent, n, namelist) 630 if (strglobmatch(ent->s, buf)) { 631 found++; 632 __del_trace_kprobe_event(fd, ent); 633 strlist__remove(namelist, ent); 634 } 635 } else { 636 ent = strlist__find(namelist, buf); 637 if (ent) { 638 found++; 639 __del_trace_kprobe_event(fd, ent); 640 strlist__remove(namelist, ent); 641 } 642 } 643 if (found == 0) 644 pr_info("Info: event \"%s\" does not exist, could not remove it.\n", buf); 645 } 646 647 void del_trace_kprobe_events(struct strlist *dellist) 648 { 649 int fd; 650 const char *group, *event; 651 char *p, *str; 652 struct str_node *ent; 653 struct strlist *namelist; 654 655 fd = open_kprobe_events(O_RDWR, O_APPEND); 656 /* Get current event names */ 657 namelist = get_perf_event_names(fd, true); 658 659 strlist__for_each(ent, dellist) { 660 str = strdup(ent->s); 661 if (!str) 662 die("Failed to copy event."); 663 pr_debug("Parsing: %s\n", str); 664 p = strchr(str, ':'); 665 if (p) { 666 group = str; 667 *p = '\0'; 668 event = p + 1; 669 } else { 670 group = "*"; 671 event = str; 672 } 673 pr_debug("Group: %s, Event: %s\n", group, event); 674 del_trace_kprobe_event(fd, group, event, namelist); 675 free(str); 676 } 677 strlist__delete(namelist); 678 close(fd); 679 } 680 681