1 /* 2 * Common code for probe-based Dynamic events. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 16 * 17 * This code was copied from kernel/trace/trace_kprobe.c written by 18 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> 19 * 20 * Updates to make this generic: 21 * Copyright (C) IBM Corporation, 2010-2011 22 * Author: Srikar Dronamraju 23 */ 24 25 #include "trace_probe.h" 26 27 const char *reserved_field_names[] = { 28 "common_type", 29 "common_flags", 30 "common_preempt_count", 31 "common_pid", 32 "common_tgid", 33 FIELD_STRING_IP, 34 FIELD_STRING_RETIP, 35 FIELD_STRING_FUNC, 36 }; 37 38 /* Printing in basic type function template */ 39 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \ 40 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, const char *name, \ 41 void *data, void *ent) \ 42 { \ 43 trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \ 44 return !trace_seq_has_overflowed(s); \ 45 } \ 46 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; \ 47 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname)); 48 49 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u") 50 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u") 51 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u") 52 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu") 53 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d") 54 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d") 55 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d") 56 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld") 57 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x") 58 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x") 59 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x") 60 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx") 61 62 /* Print type function for string type */ 63 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name, 64 void *data, void *ent) 65 { 66 int len = *(u32 *)data >> 16; 67 68 if (!len) 69 trace_seq_printf(s, " %s=(fault)", name); 70 else 71 trace_seq_printf(s, " %s=\"%s\"", name, 72 (const char *)get_loc_data(data, ent)); 73 return !trace_seq_has_overflowed(s); 74 } 75 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string)); 76 77 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\""; 78 79 #define CHECK_FETCH_FUNCS(method, fn) \ 80 (((FETCH_FUNC_NAME(method, u8) == fn) || \ 81 (FETCH_FUNC_NAME(method, u16) == fn) || \ 82 (FETCH_FUNC_NAME(method, u32) == fn) || \ 83 (FETCH_FUNC_NAME(method, u64) == fn) || \ 84 (FETCH_FUNC_NAME(method, string) == fn) || \ 85 (FETCH_FUNC_NAME(method, string_size) == fn)) \ 86 && (fn != NULL)) 87 88 /* Data fetch function templates */ 89 #define DEFINE_FETCH_reg(type) \ 90 void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \ 91 { \ 92 *(type *)dest = (type)regs_get_register(regs, \ 93 (unsigned int)((unsigned long)offset)); \ 94 } \ 95 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type)); 96 DEFINE_BASIC_FETCH_FUNCS(reg) 97 /* No string on the register */ 98 #define fetch_reg_string NULL 99 #define fetch_reg_string_size NULL 100 101 #define DEFINE_FETCH_retval(type) \ 102 void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \ 103 void *dummy, void *dest) \ 104 { \ 105 *(type *)dest = (type)regs_return_value(regs); \ 106 } \ 107 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type)); 108 DEFINE_BASIC_FETCH_FUNCS(retval) 109 /* No string on the retval */ 110 #define fetch_retval_string NULL 111 #define fetch_retval_string_size NULL 112 113 /* Dereference memory access function */ 114 struct deref_fetch_param { 115 struct fetch_param orig; 116 long offset; 117 fetch_func_t fetch; 118 fetch_func_t fetch_size; 119 }; 120 121 #define DEFINE_FETCH_deref(type) \ 122 void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \ 123 void *data, void *dest) \ 124 { \ 125 struct deref_fetch_param *dprm = data; \ 126 unsigned long addr; \ 127 call_fetch(&dprm->orig, regs, &addr); \ 128 if (addr) { \ 129 addr += dprm->offset; \ 130 dprm->fetch(regs, (void *)addr, dest); \ 131 } else \ 132 *(type *)dest = 0; \ 133 } \ 134 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type)); 135 DEFINE_BASIC_FETCH_FUNCS(deref) 136 DEFINE_FETCH_deref(string) 137 138 void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs, 139 void *data, void *dest) 140 { 141 struct deref_fetch_param *dprm = data; 142 unsigned long addr; 143 144 call_fetch(&dprm->orig, regs, &addr); 145 if (addr && dprm->fetch_size) { 146 addr += dprm->offset; 147 dprm->fetch_size(regs, (void *)addr, dest); 148 } else 149 *(string_size *)dest = 0; 150 } 151 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size)); 152 153 static void update_deref_fetch_param(struct deref_fetch_param *data) 154 { 155 if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) 156 update_deref_fetch_param(data->orig.data); 157 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) 158 update_symbol_cache(data->orig.data); 159 } 160 NOKPROBE_SYMBOL(update_deref_fetch_param); 161 162 static void free_deref_fetch_param(struct deref_fetch_param *data) 163 { 164 if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) 165 free_deref_fetch_param(data->orig.data); 166 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) 167 free_symbol_cache(data->orig.data); 168 kfree(data); 169 } 170 NOKPROBE_SYMBOL(free_deref_fetch_param); 171 172 /* Bitfield fetch function */ 173 struct bitfield_fetch_param { 174 struct fetch_param orig; 175 unsigned char hi_shift; 176 unsigned char low_shift; 177 }; 178 179 #define DEFINE_FETCH_bitfield(type) \ 180 void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \ 181 void *data, void *dest) \ 182 { \ 183 struct bitfield_fetch_param *bprm = data; \ 184 type buf = 0; \ 185 call_fetch(&bprm->orig, regs, &buf); \ 186 if (buf) { \ 187 buf <<= bprm->hi_shift; \ 188 buf >>= bprm->low_shift; \ 189 } \ 190 *(type *)dest = buf; \ 191 } \ 192 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type)); 193 DEFINE_BASIC_FETCH_FUNCS(bitfield) 194 #define fetch_bitfield_string NULL 195 #define fetch_bitfield_string_size NULL 196 197 static void 198 update_bitfield_fetch_param(struct bitfield_fetch_param *data) 199 { 200 /* 201 * Don't check the bitfield itself, because this must be the 202 * last fetch function. 203 */ 204 if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) 205 update_deref_fetch_param(data->orig.data); 206 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) 207 update_symbol_cache(data->orig.data); 208 } 209 210 static void 211 free_bitfield_fetch_param(struct bitfield_fetch_param *data) 212 { 213 /* 214 * Don't check the bitfield itself, because this must be the 215 * last fetch function. 216 */ 217 if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) 218 free_deref_fetch_param(data->orig.data); 219 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) 220 free_symbol_cache(data->orig.data); 221 222 kfree(data); 223 } 224 225 void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs, 226 void *data, void *dest) 227 { 228 int maxlen = get_rloc_len(*(u32 *)dest); 229 u8 *dst = get_rloc_data(dest); 230 long ret; 231 232 if (!maxlen) 233 return; 234 235 ret = strlcpy(dst, current->comm, maxlen); 236 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); 237 } 238 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string)); 239 240 void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs, 241 void *data, void *dest) 242 { 243 *(u32 *)dest = strlen(current->comm) + 1; 244 } 245 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size)); 246 247 static const struct fetch_type *find_fetch_type(const char *type, 248 const struct fetch_type *ftbl) 249 { 250 int i; 251 252 if (!type) 253 type = DEFAULT_FETCH_TYPE_STR; 254 255 /* Special case: bitfield */ 256 if (*type == 'b') { 257 unsigned long bs; 258 259 type = strchr(type, '/'); 260 if (!type) 261 goto fail; 262 263 type++; 264 if (kstrtoul(type, 0, &bs)) 265 goto fail; 266 267 switch (bs) { 268 case 8: 269 return find_fetch_type("u8", ftbl); 270 case 16: 271 return find_fetch_type("u16", ftbl); 272 case 32: 273 return find_fetch_type("u32", ftbl); 274 case 64: 275 return find_fetch_type("u64", ftbl); 276 default: 277 goto fail; 278 } 279 } 280 281 for (i = 0; ftbl[i].name; i++) { 282 if (strcmp(type, ftbl[i].name) == 0) 283 return &ftbl[i]; 284 } 285 286 fail: 287 return NULL; 288 } 289 290 /* Special function : only accept unsigned long */ 291 static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest) 292 { 293 *(unsigned long *)dest = kernel_stack_pointer(regs); 294 } 295 NOKPROBE_SYMBOL(fetch_kernel_stack_address); 296 297 static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest) 298 { 299 *(unsigned long *)dest = user_stack_pointer(regs); 300 } 301 NOKPROBE_SYMBOL(fetch_user_stack_address); 302 303 static fetch_func_t get_fetch_size_function(const struct fetch_type *type, 304 fetch_func_t orig_fn, 305 const struct fetch_type *ftbl) 306 { 307 int i; 308 309 if (type != &ftbl[FETCH_TYPE_STRING]) 310 return NULL; /* Only string type needs size function */ 311 312 for (i = 0; i < FETCH_MTD_END; i++) 313 if (type->fetch[i] == orig_fn) 314 return ftbl[FETCH_TYPE_STRSIZE].fetch[i]; 315 316 WARN_ON(1); /* This should not happen */ 317 318 return NULL; 319 } 320 321 /* Split symbol and offset. */ 322 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset) 323 { 324 char *tmp; 325 int ret; 326 327 if (!offset) 328 return -EINVAL; 329 330 tmp = strchr(symbol, '+'); 331 if (tmp) { 332 /* skip sign because kstrtoul doesn't accept '+' */ 333 ret = kstrtoul(tmp + 1, 0, offset); 334 if (ret) 335 return ret; 336 337 *tmp = '\0'; 338 } else 339 *offset = 0; 340 341 return 0; 342 } 343 344 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) 345 346 static int parse_probe_vars(char *arg, const struct fetch_type *t, 347 struct fetch_param *f, bool is_return, 348 bool is_kprobe) 349 { 350 int ret = 0; 351 unsigned long param; 352 353 if (strcmp(arg, "retval") == 0) { 354 if (is_return) 355 f->fn = t->fetch[FETCH_MTD_retval]; 356 else 357 ret = -EINVAL; 358 } else if (strncmp(arg, "stack", 5) == 0) { 359 if (arg[5] == '\0') { 360 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR)) 361 return -EINVAL; 362 363 if (is_kprobe) 364 f->fn = fetch_kernel_stack_address; 365 else 366 f->fn = fetch_user_stack_address; 367 } else if (isdigit(arg[5])) { 368 ret = kstrtoul(arg + 5, 10, ¶m); 369 if (ret || (is_kprobe && param > PARAM_MAX_STACK)) 370 ret = -EINVAL; 371 else { 372 f->fn = t->fetch[FETCH_MTD_stack]; 373 f->data = (void *)param; 374 } 375 } else 376 ret = -EINVAL; 377 } else if (strcmp(arg, "comm") == 0) { 378 if (strcmp(t->name, "string") != 0 && 379 strcmp(t->name, "string_size") != 0) 380 return -EINVAL; 381 f->fn = t->fetch[FETCH_MTD_comm]; 382 } else 383 ret = -EINVAL; 384 385 return ret; 386 } 387 388 /* Recursive argument parser */ 389 static int parse_probe_arg(char *arg, const struct fetch_type *t, 390 struct fetch_param *f, bool is_return, bool is_kprobe, 391 const struct fetch_type *ftbl) 392 { 393 unsigned long param; 394 long offset; 395 char *tmp; 396 int ret = 0; 397 398 switch (arg[0]) { 399 case '$': 400 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe); 401 break; 402 403 case '%': /* named register */ 404 ret = regs_query_register_offset(arg + 1); 405 if (ret >= 0) { 406 f->fn = t->fetch[FETCH_MTD_reg]; 407 f->data = (void *)(unsigned long)ret; 408 ret = 0; 409 } 410 break; 411 412 case '@': /* memory, file-offset or symbol */ 413 if (isdigit(arg[1])) { 414 ret = kstrtoul(arg + 1, 0, ¶m); 415 if (ret) 416 break; 417 418 f->fn = t->fetch[FETCH_MTD_memory]; 419 f->data = (void *)param; 420 } else if (arg[1] == '+') { 421 /* kprobes don't support file offsets */ 422 if (is_kprobe) 423 return -EINVAL; 424 425 ret = kstrtol(arg + 2, 0, &offset); 426 if (ret) 427 break; 428 429 f->fn = t->fetch[FETCH_MTD_file_offset]; 430 f->data = (void *)offset; 431 } else { 432 /* uprobes don't support symbols */ 433 if (!is_kprobe) 434 return -EINVAL; 435 436 ret = traceprobe_split_symbol_offset(arg + 1, &offset); 437 if (ret) 438 break; 439 440 f->data = alloc_symbol_cache(arg + 1, offset); 441 if (f->data) 442 f->fn = t->fetch[FETCH_MTD_symbol]; 443 } 444 break; 445 446 case '+': /* deref memory */ 447 arg++; /* Skip '+', because kstrtol() rejects it. */ 448 case '-': 449 tmp = strchr(arg, '('); 450 if (!tmp) 451 break; 452 453 *tmp = '\0'; 454 ret = kstrtol(arg, 0, &offset); 455 456 if (ret) 457 break; 458 459 arg = tmp + 1; 460 tmp = strrchr(arg, ')'); 461 462 if (tmp) { 463 struct deref_fetch_param *dprm; 464 const struct fetch_type *t2; 465 466 t2 = find_fetch_type(NULL, ftbl); 467 *tmp = '\0'; 468 dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL); 469 470 if (!dprm) 471 return -ENOMEM; 472 473 dprm->offset = offset; 474 dprm->fetch = t->fetch[FETCH_MTD_memory]; 475 dprm->fetch_size = get_fetch_size_function(t, 476 dprm->fetch, ftbl); 477 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return, 478 is_kprobe, ftbl); 479 if (ret) 480 kfree(dprm); 481 else { 482 f->fn = t->fetch[FETCH_MTD_deref]; 483 f->data = (void *)dprm; 484 } 485 } 486 break; 487 } 488 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */ 489 pr_info("%s type has no corresponding fetch method.\n", t->name); 490 ret = -EINVAL; 491 } 492 493 return ret; 494 } 495 496 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long)) 497 498 /* Bitfield type needs to be parsed into a fetch function */ 499 static int __parse_bitfield_probe_arg(const char *bf, 500 const struct fetch_type *t, 501 struct fetch_param *f) 502 { 503 struct bitfield_fetch_param *bprm; 504 unsigned long bw, bo; 505 char *tail; 506 507 if (*bf != 'b') 508 return 0; 509 510 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); 511 if (!bprm) 512 return -ENOMEM; 513 514 bprm->orig = *f; 515 f->fn = t->fetch[FETCH_MTD_bitfield]; 516 f->data = (void *)bprm; 517 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */ 518 519 if (bw == 0 || *tail != '@') 520 return -EINVAL; 521 522 bf = tail + 1; 523 bo = simple_strtoul(bf, &tail, 0); 524 525 if (tail == bf || *tail != '/') 526 return -EINVAL; 527 528 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo); 529 bprm->low_shift = bprm->hi_shift + bo; 530 531 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; 532 } 533 534 /* String length checking wrapper */ 535 int traceprobe_parse_probe_arg(char *arg, ssize_t *size, 536 struct probe_arg *parg, bool is_return, bool is_kprobe, 537 const struct fetch_type *ftbl) 538 { 539 const char *t; 540 int ret; 541 542 if (strlen(arg) > MAX_ARGSTR_LEN) { 543 pr_info("Argument is too long.: %s\n", arg); 544 return -ENOSPC; 545 } 546 parg->comm = kstrdup(arg, GFP_KERNEL); 547 if (!parg->comm) { 548 pr_info("Failed to allocate memory for command '%s'.\n", arg); 549 return -ENOMEM; 550 } 551 t = strchr(parg->comm, ':'); 552 if (t) { 553 arg[t - parg->comm] = '\0'; 554 t++; 555 } 556 /* 557 * The default type of $comm should be "string", and it can't be 558 * dereferenced. 559 */ 560 if (!t && strcmp(arg, "$comm") == 0) 561 t = "string"; 562 parg->type = find_fetch_type(t, ftbl); 563 if (!parg->type) { 564 pr_info("Unsupported type: %s\n", t); 565 return -EINVAL; 566 } 567 parg->offset = *size; 568 *size += parg->type->size; 569 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, 570 is_kprobe, ftbl); 571 572 if (ret >= 0 && t != NULL) 573 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch); 574 575 if (ret >= 0) { 576 parg->fetch_size.fn = get_fetch_size_function(parg->type, 577 parg->fetch.fn, 578 ftbl); 579 parg->fetch_size.data = parg->fetch.data; 580 } 581 582 return ret; 583 } 584 585 /* Return 1 if name is reserved or already used by another argument */ 586 int traceprobe_conflict_field_name(const char *name, 587 struct probe_arg *args, int narg) 588 { 589 int i; 590 591 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) 592 if (strcmp(reserved_field_names[i], name) == 0) 593 return 1; 594 595 for (i = 0; i < narg; i++) 596 if (strcmp(args[i].name, name) == 0) 597 return 1; 598 599 return 0; 600 } 601 602 void traceprobe_update_arg(struct probe_arg *arg) 603 { 604 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn)) 605 update_bitfield_fetch_param(arg->fetch.data); 606 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn)) 607 update_deref_fetch_param(arg->fetch.data); 608 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn)) 609 update_symbol_cache(arg->fetch.data); 610 } 611 612 void traceprobe_free_probe_arg(struct probe_arg *arg) 613 { 614 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn)) 615 free_bitfield_fetch_param(arg->fetch.data); 616 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn)) 617 free_deref_fetch_param(arg->fetch.data); 618 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn)) 619 free_symbol_cache(arg->fetch.data); 620 621 kfree(arg->name); 622 kfree(arg->comm); 623 } 624 625 int traceprobe_command(const char *buf, int (*createfn)(int, char **)) 626 { 627 char **argv; 628 int argc, ret; 629 630 argc = 0; 631 ret = 0; 632 argv = argv_split(GFP_KERNEL, buf, &argc); 633 if (!argv) 634 return -ENOMEM; 635 636 if (argc) 637 ret = createfn(argc, argv); 638 639 argv_free(argv); 640 641 return ret; 642 } 643 644 #define WRITE_BUFSIZE 4096 645 646 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer, 647 size_t count, loff_t *ppos, 648 int (*createfn)(int, char **)) 649 { 650 char *kbuf, *tmp; 651 int ret = 0; 652 size_t done = 0; 653 size_t size; 654 655 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL); 656 if (!kbuf) 657 return -ENOMEM; 658 659 while (done < count) { 660 size = count - done; 661 662 if (size >= WRITE_BUFSIZE) 663 size = WRITE_BUFSIZE - 1; 664 665 if (copy_from_user(kbuf, buffer + done, size)) { 666 ret = -EFAULT; 667 goto out; 668 } 669 kbuf[size] = '\0'; 670 tmp = strchr(kbuf, '\n'); 671 672 if (tmp) { 673 *tmp = '\0'; 674 size = tmp - kbuf + 1; 675 } else if (done + size < count) { 676 pr_warn("Line length is too long: Should be less than %d\n", 677 WRITE_BUFSIZE); 678 ret = -EINVAL; 679 goto out; 680 } 681 done += size; 682 /* Remove comments */ 683 tmp = strchr(kbuf, '#'); 684 685 if (tmp) 686 *tmp = '\0'; 687 688 ret = traceprobe_command(kbuf, createfn); 689 if (ret) 690 goto out; 691 } 692 ret = done; 693 694 out: 695 kfree(kbuf); 696 697 return ret; 698 } 699 700 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, 701 bool is_return) 702 { 703 int i; 704 int pos = 0; 705 706 const char *fmt, *arg; 707 708 if (!is_return) { 709 fmt = "(%lx)"; 710 arg = "REC->" FIELD_STRING_IP; 711 } else { 712 fmt = "(%lx <- %lx)"; 713 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 714 } 715 716 /* When len=0, we just calculate the needed length */ 717 #define LEN_OR_ZERO (len ? len - pos : 0) 718 719 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 720 721 for (i = 0; i < tp->nr_args; i++) { 722 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", 723 tp->args[i].name, tp->args[i].type->fmt); 724 } 725 726 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); 727 728 for (i = 0; i < tp->nr_args; i++) { 729 if (strcmp(tp->args[i].type->name, "string") == 0) 730 pos += snprintf(buf + pos, LEN_OR_ZERO, 731 ", __get_str(%s)", 732 tp->args[i].name); 733 else 734 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", 735 tp->args[i].name); 736 } 737 738 #undef LEN_OR_ZERO 739 740 /* return the length of print_fmt */ 741 return pos; 742 } 743 744 int set_print_fmt(struct trace_probe *tp, bool is_return) 745 { 746 int len; 747 char *print_fmt; 748 749 /* First: called with 0 length to calculate the needed length */ 750 len = __set_print_fmt(tp, NULL, 0, is_return); 751 print_fmt = kmalloc(len + 1, GFP_KERNEL); 752 if (!print_fmt) 753 return -ENOMEM; 754 755 /* Second: actually write the @print_fmt */ 756 __set_print_fmt(tp, print_fmt, len + 1, is_return); 757 tp->call.print_fmt = print_fmt; 758 759 return 0; 760 } 761