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