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 } 677 678