1 /* 2 * probe-finder.c : C expression to kprobe event 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 #include <sys/utsname.h> 23 #include <sys/types.h> 24 #include <sys/stat.h> 25 #include <fcntl.h> 26 #include <errno.h> 27 #include <stdio.h> 28 #include <unistd.h> 29 #include <stdlib.h> 30 #include <string.h> 31 #include <stdarg.h> 32 #include <dwarf-regs.h> 33 34 #include <linux/bitops.h> 35 #include "event.h" 36 #include "dso.h" 37 #include "debug.h" 38 #include "intlist.h" 39 #include "util.h" 40 #include "symbol.h" 41 #include "probe-finder.h" 42 43 /* Kprobe tracer basic type is up to u64 */ 44 #define MAX_BASIC_TYPE_BITS 64 45 46 /* Dwarf FL wrappers */ 47 static char *debuginfo_path; /* Currently dummy */ 48 49 static const Dwfl_Callbacks offline_callbacks = { 50 .find_debuginfo = dwfl_standard_find_debuginfo, 51 .debuginfo_path = &debuginfo_path, 52 53 .section_address = dwfl_offline_section_address, 54 55 /* We use this table for core files too. */ 56 .find_elf = dwfl_build_id_find_elf, 57 }; 58 59 /* Get a Dwarf from offline image */ 60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg, 61 const char *path) 62 { 63 int fd; 64 65 fd = open(path, O_RDONLY); 66 if (fd < 0) 67 return fd; 68 69 dbg->dwfl = dwfl_begin(&offline_callbacks); 70 if (!dbg->dwfl) 71 goto error; 72 73 dwfl_report_begin(dbg->dwfl); 74 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd); 75 if (!dbg->mod) 76 goto error; 77 78 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias); 79 if (!dbg->dbg) 80 goto error; 81 82 dwfl_report_end(dbg->dwfl, NULL, NULL); 83 84 return 0; 85 error: 86 if (dbg->dwfl) 87 dwfl_end(dbg->dwfl); 88 else 89 close(fd); 90 memset(dbg, 0, sizeof(*dbg)); 91 92 return -ENOENT; 93 } 94 95 static struct debuginfo *__debuginfo__new(const char *path) 96 { 97 struct debuginfo *dbg = zalloc(sizeof(*dbg)); 98 if (!dbg) 99 return NULL; 100 101 if (debuginfo__init_offline_dwarf(dbg, path) < 0) 102 zfree(&dbg); 103 if (dbg) 104 pr_debug("Open Debuginfo file: %s\n", path); 105 return dbg; 106 } 107 108 enum dso_binary_type distro_dwarf_types[] = { 109 DSO_BINARY_TYPE__FEDORA_DEBUGINFO, 110 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO, 111 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO, 112 DSO_BINARY_TYPE__BUILDID_DEBUGINFO, 113 DSO_BINARY_TYPE__NOT_FOUND, 114 }; 115 116 struct debuginfo *debuginfo__new(const char *path) 117 { 118 enum dso_binary_type *type; 119 char buf[PATH_MAX], nil = '\0'; 120 struct dso *dso; 121 struct debuginfo *dinfo = NULL; 122 123 /* Try to open distro debuginfo files */ 124 dso = dso__new(path); 125 if (!dso) 126 goto out; 127 128 for (type = distro_dwarf_types; 129 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND; 130 type++) { 131 if (dso__read_binary_type_filename(dso, *type, &nil, 132 buf, PATH_MAX) < 0) 133 continue; 134 dinfo = __debuginfo__new(buf); 135 } 136 dso__put(dso); 137 138 out: 139 /* if failed to open all distro debuginfo, open given binary */ 140 return dinfo ? : __debuginfo__new(path); 141 } 142 143 void debuginfo__delete(struct debuginfo *dbg) 144 { 145 if (dbg) { 146 if (dbg->dwfl) 147 dwfl_end(dbg->dwfl); 148 free(dbg); 149 } 150 } 151 152 /* 153 * Probe finder related functions 154 */ 155 156 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs) 157 { 158 struct probe_trace_arg_ref *ref; 159 ref = zalloc(sizeof(struct probe_trace_arg_ref)); 160 if (ref != NULL) 161 ref->offset = offs; 162 return ref; 163 } 164 165 /* 166 * Convert a location into trace_arg. 167 * If tvar == NULL, this just checks variable can be converted. 168 * If fentry == true and vr_die is a parameter, do huristic search 169 * for the location fuzzed by function entry mcount. 170 */ 171 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr, 172 Dwarf_Op *fb_ops, Dwarf_Die *sp_die, 173 struct probe_trace_arg *tvar) 174 { 175 Dwarf_Attribute attr; 176 Dwarf_Addr tmp = 0; 177 Dwarf_Op *op; 178 size_t nops; 179 unsigned int regn; 180 Dwarf_Word offs = 0; 181 bool ref = false; 182 const char *regs; 183 int ret, ret2 = 0; 184 185 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL) 186 goto static_var; 187 188 /* TODO: handle more than 1 exprs */ 189 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL) 190 return -EINVAL; /* Broken DIE ? */ 191 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) { 192 ret = dwarf_entrypc(sp_die, &tmp); 193 if (ret) 194 return -ENOENT; 195 196 if (probe_conf.show_location_range && 197 (dwarf_tag(vr_die) == DW_TAG_variable)) { 198 ret2 = -ERANGE; 199 } else if (addr != tmp || 200 dwarf_tag(vr_die) != DW_TAG_formal_parameter) { 201 return -ENOENT; 202 } 203 204 ret = dwarf_highpc(sp_die, &tmp); 205 if (ret) 206 return -ENOENT; 207 /* 208 * This is fuzzed by fentry mcount. We try to find the 209 * parameter location at the earliest address. 210 */ 211 for (addr += 1; addr <= tmp; addr++) { 212 if (dwarf_getlocation_addr(&attr, addr, &op, 213 &nops, 1) > 0) 214 goto found; 215 } 216 return -ENOENT; 217 } 218 found: 219 if (nops == 0) 220 /* TODO: Support const_value */ 221 return -ENOENT; 222 223 if (op->atom == DW_OP_addr) { 224 static_var: 225 if (!tvar) 226 return ret2; 227 /* Static variables on memory (not stack), make @varname */ 228 ret = strlen(dwarf_diename(vr_die)); 229 tvar->value = zalloc(ret + 2); 230 if (tvar->value == NULL) 231 return -ENOMEM; 232 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die)); 233 tvar->ref = alloc_trace_arg_ref((long)offs); 234 if (tvar->ref == NULL) 235 return -ENOMEM; 236 return ret2; 237 } 238 239 /* If this is based on frame buffer, set the offset */ 240 if (op->atom == DW_OP_fbreg) { 241 if (fb_ops == NULL) 242 return -ENOTSUP; 243 ref = true; 244 offs = op->number; 245 op = &fb_ops[0]; 246 } 247 248 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) { 249 regn = op->atom - DW_OP_breg0; 250 offs += op->number; 251 ref = true; 252 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) { 253 regn = op->atom - DW_OP_reg0; 254 } else if (op->atom == DW_OP_bregx) { 255 regn = op->number; 256 offs += op->number2; 257 ref = true; 258 } else if (op->atom == DW_OP_regx) { 259 regn = op->number; 260 } else { 261 pr_debug("DW_OP %x is not supported.\n", op->atom); 262 return -ENOTSUP; 263 } 264 265 if (!tvar) 266 return ret2; 267 268 regs = get_arch_regstr(regn); 269 if (!regs) { 270 /* This should be a bug in DWARF or this tool */ 271 pr_warning("Mapping for the register number %u " 272 "missing on this architecture.\n", regn); 273 return -ENOTSUP; 274 } 275 276 tvar->value = strdup(regs); 277 if (tvar->value == NULL) 278 return -ENOMEM; 279 280 if (ref) { 281 tvar->ref = alloc_trace_arg_ref((long)offs); 282 if (tvar->ref == NULL) 283 return -ENOMEM; 284 } 285 return ret2; 286 } 287 288 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long)) 289 290 static int convert_variable_type(Dwarf_Die *vr_die, 291 struct probe_trace_arg *tvar, 292 const char *cast) 293 { 294 struct probe_trace_arg_ref **ref_ptr = &tvar->ref; 295 Dwarf_Die type; 296 char buf[16]; 297 char sbuf[STRERR_BUFSIZE]; 298 int bsize, boffs, total; 299 int ret; 300 301 /* TODO: check all types */ 302 if (cast && strcmp(cast, "string") != 0) { 303 /* Non string type is OK */ 304 tvar->type = strdup(cast); 305 return (tvar->type == NULL) ? -ENOMEM : 0; 306 } 307 308 bsize = dwarf_bitsize(vr_die); 309 if (bsize > 0) { 310 /* This is a bitfield */ 311 boffs = dwarf_bitoffset(vr_die); 312 total = dwarf_bytesize(vr_die); 313 if (boffs < 0 || total < 0) 314 return -ENOENT; 315 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs, 316 BYTES_TO_BITS(total)); 317 goto formatted; 318 } 319 320 if (die_get_real_type(vr_die, &type) == NULL) { 321 pr_warning("Failed to get a type information of %s.\n", 322 dwarf_diename(vr_die)); 323 return -ENOENT; 324 } 325 326 pr_debug("%s type is %s.\n", 327 dwarf_diename(vr_die), dwarf_diename(&type)); 328 329 if (cast && strcmp(cast, "string") == 0) { /* String type */ 330 ret = dwarf_tag(&type); 331 if (ret != DW_TAG_pointer_type && 332 ret != DW_TAG_array_type) { 333 pr_warning("Failed to cast into string: " 334 "%s(%s) is not a pointer nor array.\n", 335 dwarf_diename(vr_die), dwarf_diename(&type)); 336 return -EINVAL; 337 } 338 if (die_get_real_type(&type, &type) == NULL) { 339 pr_warning("Failed to get a type" 340 " information.\n"); 341 return -ENOENT; 342 } 343 if (ret == DW_TAG_pointer_type) { 344 while (*ref_ptr) 345 ref_ptr = &(*ref_ptr)->next; 346 /* Add new reference with offset +0 */ 347 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref)); 348 if (*ref_ptr == NULL) { 349 pr_warning("Out of memory error\n"); 350 return -ENOMEM; 351 } 352 } 353 if (!die_compare_name(&type, "char") && 354 !die_compare_name(&type, "unsigned char")) { 355 pr_warning("Failed to cast into string: " 356 "%s is not (unsigned) char *.\n", 357 dwarf_diename(vr_die)); 358 return -EINVAL; 359 } 360 tvar->type = strdup(cast); 361 return (tvar->type == NULL) ? -ENOMEM : 0; 362 } 363 364 ret = dwarf_bytesize(&type); 365 if (ret <= 0) 366 /* No size ... try to use default type */ 367 return 0; 368 ret = BYTES_TO_BITS(ret); 369 370 /* Check the bitwidth */ 371 if (ret > MAX_BASIC_TYPE_BITS) { 372 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n", 373 dwarf_diename(&type), MAX_BASIC_TYPE_BITS); 374 ret = MAX_BASIC_TYPE_BITS; 375 } 376 ret = snprintf(buf, 16, "%c%d", 377 die_is_signed_type(&type) ? 's' : 'u', ret); 378 379 formatted: 380 if (ret < 0 || ret >= 16) { 381 if (ret >= 16) 382 ret = -E2BIG; 383 pr_warning("Failed to convert variable type: %s\n", 384 strerror_r(-ret, sbuf, sizeof(sbuf))); 385 return ret; 386 } 387 tvar->type = strdup(buf); 388 if (tvar->type == NULL) 389 return -ENOMEM; 390 return 0; 391 } 392 393 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, 394 struct perf_probe_arg_field *field, 395 struct probe_trace_arg_ref **ref_ptr, 396 Dwarf_Die *die_mem) 397 { 398 struct probe_trace_arg_ref *ref = *ref_ptr; 399 Dwarf_Die type; 400 Dwarf_Word offs; 401 int ret, tag; 402 403 pr_debug("converting %s in %s\n", field->name, varname); 404 if (die_get_real_type(vr_die, &type) == NULL) { 405 pr_warning("Failed to get the type of %s.\n", varname); 406 return -ENOENT; 407 } 408 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); 409 tag = dwarf_tag(&type); 410 411 if (field->name[0] == '[' && 412 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { 413 if (field->next) 414 /* Save original type for next field */ 415 memcpy(die_mem, &type, sizeof(*die_mem)); 416 /* Get the type of this array */ 417 if (die_get_real_type(&type, &type) == NULL) { 418 pr_warning("Failed to get the type of %s.\n", varname); 419 return -ENOENT; 420 } 421 pr_debug2("Array real type: (%x)\n", 422 (unsigned)dwarf_dieoffset(&type)); 423 if (tag == DW_TAG_pointer_type) { 424 ref = zalloc(sizeof(struct probe_trace_arg_ref)); 425 if (ref == NULL) 426 return -ENOMEM; 427 if (*ref_ptr) 428 (*ref_ptr)->next = ref; 429 else 430 *ref_ptr = ref; 431 } 432 ref->offset += dwarf_bytesize(&type) * field->index; 433 if (!field->next) 434 /* Save vr_die for converting types */ 435 memcpy(die_mem, vr_die, sizeof(*die_mem)); 436 goto next; 437 } else if (tag == DW_TAG_pointer_type) { 438 /* Check the pointer and dereference */ 439 if (!field->ref) { 440 pr_err("Semantic error: %s must be referred by '->'\n", 441 field->name); 442 return -EINVAL; 443 } 444 /* Get the type pointed by this pointer */ 445 if (die_get_real_type(&type, &type) == NULL) { 446 pr_warning("Failed to get the type of %s.\n", varname); 447 return -ENOENT; 448 } 449 /* Verify it is a data structure */ 450 tag = dwarf_tag(&type); 451 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { 452 pr_warning("%s is not a data structure nor an union.\n", 453 varname); 454 return -EINVAL; 455 } 456 457 ref = zalloc(sizeof(struct probe_trace_arg_ref)); 458 if (ref == NULL) 459 return -ENOMEM; 460 if (*ref_ptr) 461 (*ref_ptr)->next = ref; 462 else 463 *ref_ptr = ref; 464 } else { 465 /* Verify it is a data structure */ 466 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { 467 pr_warning("%s is not a data structure nor an union.\n", 468 varname); 469 return -EINVAL; 470 } 471 if (field->name[0] == '[') { 472 pr_err("Semantic error: %s is not a pointer" 473 " nor array.\n", varname); 474 return -EINVAL; 475 } 476 /* While prcessing unnamed field, we don't care about this */ 477 if (field->ref && dwarf_diename(vr_die)) { 478 pr_err("Semantic error: %s must be referred by '.'\n", 479 field->name); 480 return -EINVAL; 481 } 482 if (!ref) { 483 pr_warning("Structure on a register is not " 484 "supported yet.\n"); 485 return -ENOTSUP; 486 } 487 } 488 489 if (die_find_member(&type, field->name, die_mem) == NULL) { 490 pr_warning("%s(type:%s) has no member %s.\n", varname, 491 dwarf_diename(&type), field->name); 492 return -EINVAL; 493 } 494 495 /* Get the offset of the field */ 496 if (tag == DW_TAG_union_type) { 497 offs = 0; 498 } else { 499 ret = die_get_data_member_location(die_mem, &offs); 500 if (ret < 0) { 501 pr_warning("Failed to get the offset of %s.\n", 502 field->name); 503 return ret; 504 } 505 } 506 ref->offset += (long)offs; 507 508 /* If this member is unnamed, we need to reuse this field */ 509 if (!dwarf_diename(die_mem)) 510 return convert_variable_fields(die_mem, varname, field, 511 &ref, die_mem); 512 513 next: 514 /* Converting next field */ 515 if (field->next) 516 return convert_variable_fields(die_mem, field->name, 517 field->next, &ref, die_mem); 518 else 519 return 0; 520 } 521 522 /* Show a variables in kprobe event format */ 523 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf) 524 { 525 Dwarf_Die die_mem; 526 int ret; 527 528 pr_debug("Converting variable %s into trace event.\n", 529 dwarf_diename(vr_die)); 530 531 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops, 532 &pf->sp_die, pf->tvar); 533 if (ret == -ENOENT || ret == -EINVAL) { 534 pr_err("Failed to find the location of the '%s' variable at this address.\n" 535 " Perhaps it has been optimized out.\n" 536 " Use -V with the --range option to show '%s' location range.\n", 537 pf->pvar->var, pf->pvar->var); 538 } else if (ret == -ENOTSUP) 539 pr_err("Sorry, we don't support this variable location yet.\n"); 540 else if (ret == 0 && pf->pvar->field) { 541 ret = convert_variable_fields(vr_die, pf->pvar->var, 542 pf->pvar->field, &pf->tvar->ref, 543 &die_mem); 544 vr_die = &die_mem; 545 } 546 if (ret == 0) 547 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type); 548 /* *expr will be cached in libdw. Don't free it. */ 549 return ret; 550 } 551 552 /* Find a variable in a scope DIE */ 553 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) 554 { 555 Dwarf_Die vr_die; 556 char buf[32], *ptr; 557 int ret = 0; 558 559 /* Copy raw parameters */ 560 if (!is_c_varname(pf->pvar->var)) 561 return copy_to_probe_trace_arg(pf->tvar, pf->pvar); 562 563 if (pf->pvar->name) 564 pf->tvar->name = strdup(pf->pvar->name); 565 else { 566 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32); 567 if (ret < 0) 568 return ret; 569 ptr = strchr(buf, ':'); /* Change type separator to _ */ 570 if (ptr) 571 *ptr = '_'; 572 pf->tvar->name = strdup(buf); 573 } 574 if (pf->tvar->name == NULL) 575 return -ENOMEM; 576 577 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var); 578 /* Search child die for local variables and parameters. */ 579 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) { 580 /* Search again in global variables */ 581 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 582 0, &vr_die)) { 583 pr_warning("Failed to find '%s' in this function.\n", 584 pf->pvar->var); 585 ret = -ENOENT; 586 } 587 } 588 if (ret >= 0) 589 ret = convert_variable(&vr_die, pf); 590 591 return ret; 592 } 593 594 /* Convert subprogram DIE to trace point */ 595 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod, 596 Dwarf_Addr paddr, bool retprobe, 597 const char *function, 598 struct probe_trace_point *tp) 599 { 600 Dwarf_Addr eaddr, highaddr; 601 GElf_Sym sym; 602 const char *symbol; 603 604 /* Verify the address is correct */ 605 if (dwarf_entrypc(sp_die, &eaddr) != 0) { 606 pr_warning("Failed to get entry address of %s\n", 607 dwarf_diename(sp_die)); 608 return -ENOENT; 609 } 610 if (dwarf_highpc(sp_die, &highaddr) != 0) { 611 pr_warning("Failed to get end address of %s\n", 612 dwarf_diename(sp_die)); 613 return -ENOENT; 614 } 615 if (paddr > highaddr) { 616 pr_warning("Offset specified is greater than size of %s\n", 617 dwarf_diename(sp_die)); 618 return -EINVAL; 619 } 620 621 symbol = dwarf_diename(sp_die); 622 if (!symbol) { 623 /* Try to get the symbol name from symtab */ 624 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL); 625 if (!symbol) { 626 pr_warning("Failed to find symbol at 0x%lx\n", 627 (unsigned long)paddr); 628 return -ENOENT; 629 } 630 eaddr = sym.st_value; 631 } 632 tp->offset = (unsigned long)(paddr - eaddr); 633 tp->address = (unsigned long)paddr; 634 tp->symbol = strdup(symbol); 635 if (!tp->symbol) 636 return -ENOMEM; 637 638 /* Return probe must be on the head of a subprogram */ 639 if (retprobe) { 640 if (eaddr != paddr) { 641 pr_warning("Failed to find \"%s%%return\",\n" 642 " because %s is an inlined function and" 643 " has no return point.\n", function, 644 function); 645 return -EINVAL; 646 } 647 tp->retprobe = true; 648 } 649 650 return 0; 651 } 652 653 /* Call probe_finder callback with scope DIE */ 654 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf) 655 { 656 Dwarf_Attribute fb_attr; 657 size_t nops; 658 int ret; 659 660 if (!sc_die) { 661 pr_err("Caller must pass a scope DIE. Program error.\n"); 662 return -EINVAL; 663 } 664 665 /* If not a real subprogram, find a real one */ 666 if (!die_is_func_def(sc_die)) { 667 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { 668 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { 669 pr_warning("Ignoring tail call from %s\n", 670 dwarf_diename(&pf->sp_die)); 671 return 0; 672 } else { 673 pr_warning("Failed to find probe point in any " 674 "functions.\n"); 675 return -ENOENT; 676 } 677 } 678 } else 679 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die)); 680 681 /* Get the frame base attribute/ops from subprogram */ 682 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr); 683 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1); 684 if (ret <= 0 || nops == 0) { 685 pf->fb_ops = NULL; 686 #if _ELFUTILS_PREREQ(0, 142) 687 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa && 688 pf->cfi != NULL) { 689 Dwarf_Frame *frame; 690 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 || 691 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) { 692 pr_warning("Failed to get call frame on 0x%jx\n", 693 (uintmax_t)pf->addr); 694 return -ENOENT; 695 } 696 #endif 697 } 698 699 /* Call finder's callback handler */ 700 ret = pf->callback(sc_die, pf); 701 702 /* *pf->fb_ops will be cached in libdw. Don't free it. */ 703 pf->fb_ops = NULL; 704 705 return ret; 706 } 707 708 struct find_scope_param { 709 const char *function; 710 const char *file; 711 int line; 712 int diff; 713 Dwarf_Die *die_mem; 714 bool found; 715 }; 716 717 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data) 718 { 719 struct find_scope_param *fsp = data; 720 const char *file; 721 int lno; 722 723 /* Skip if declared file name does not match */ 724 if (fsp->file) { 725 file = dwarf_decl_file(fn_die); 726 if (!file || strcmp(fsp->file, file) != 0) 727 return 0; 728 } 729 /* If the function name is given, that's what user expects */ 730 if (fsp->function) { 731 if (die_match_name(fn_die, fsp->function)) { 732 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); 733 fsp->found = true; 734 return 1; 735 } 736 } else { 737 /* With the line number, find the nearest declared DIE */ 738 dwarf_decl_line(fn_die, &lno); 739 if (lno < fsp->line && fsp->diff > fsp->line - lno) { 740 /* Keep a candidate and continue */ 741 fsp->diff = fsp->line - lno; 742 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); 743 fsp->found = true; 744 } 745 } 746 return 0; 747 } 748 749 /* Find an appropriate scope fits to given conditions */ 750 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem) 751 { 752 struct find_scope_param fsp = { 753 .function = pf->pev->point.function, 754 .file = pf->fname, 755 .line = pf->lno, 756 .diff = INT_MAX, 757 .die_mem = die_mem, 758 .found = false, 759 }; 760 761 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp); 762 763 return fsp.found ? die_mem : NULL; 764 } 765 766 static int probe_point_line_walker(const char *fname, int lineno, 767 Dwarf_Addr addr, void *data) 768 { 769 struct probe_finder *pf = data; 770 Dwarf_Die *sc_die, die_mem; 771 int ret; 772 773 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0) 774 return 0; 775 776 pf->addr = addr; 777 sc_die = find_best_scope(pf, &die_mem); 778 if (!sc_die) { 779 pr_warning("Failed to find scope of probe point.\n"); 780 return -ENOENT; 781 } 782 783 ret = call_probe_finder(sc_die, pf); 784 785 /* Continue if no error, because the line will be in inline function */ 786 return ret < 0 ? ret : 0; 787 } 788 789 /* Find probe point from its line number */ 790 static int find_probe_point_by_line(struct probe_finder *pf) 791 { 792 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf); 793 } 794 795 /* Find lines which match lazy pattern */ 796 static int find_lazy_match_lines(struct intlist *list, 797 const char *fname, const char *pat) 798 { 799 FILE *fp; 800 char *line = NULL; 801 size_t line_len; 802 ssize_t len; 803 int count = 0, linenum = 1; 804 char sbuf[STRERR_BUFSIZE]; 805 806 fp = fopen(fname, "r"); 807 if (!fp) { 808 pr_warning("Failed to open %s: %s\n", fname, 809 strerror_r(errno, sbuf, sizeof(sbuf))); 810 return -errno; 811 } 812 813 while ((len = getline(&line, &line_len, fp)) > 0) { 814 815 if (line[len - 1] == '\n') 816 line[len - 1] = '\0'; 817 818 if (strlazymatch(line, pat)) { 819 intlist__add(list, linenum); 820 count++; 821 } 822 linenum++; 823 } 824 825 if (ferror(fp)) 826 count = -errno; 827 free(line); 828 fclose(fp); 829 830 if (count == 0) 831 pr_debug("No matched lines found in %s.\n", fname); 832 return count; 833 } 834 835 static int probe_point_lazy_walker(const char *fname, int lineno, 836 Dwarf_Addr addr, void *data) 837 { 838 struct probe_finder *pf = data; 839 Dwarf_Die *sc_die, die_mem; 840 int ret; 841 842 if (!intlist__has_entry(pf->lcache, lineno) || 843 strtailcmp(fname, pf->fname) != 0) 844 return 0; 845 846 pr_debug("Probe line found: line:%d addr:0x%llx\n", 847 lineno, (unsigned long long)addr); 848 pf->addr = addr; 849 pf->lno = lineno; 850 sc_die = find_best_scope(pf, &die_mem); 851 if (!sc_die) { 852 pr_warning("Failed to find scope of probe point.\n"); 853 return -ENOENT; 854 } 855 856 ret = call_probe_finder(sc_die, pf); 857 858 /* 859 * Continue if no error, because the lazy pattern will match 860 * to other lines 861 */ 862 return ret < 0 ? ret : 0; 863 } 864 865 /* Find probe points from lazy pattern */ 866 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) 867 { 868 int ret = 0; 869 char *fpath; 870 871 if (intlist__empty(pf->lcache)) { 872 const char *comp_dir; 873 874 comp_dir = cu_get_comp_dir(&pf->cu_die); 875 ret = get_real_path(pf->fname, comp_dir, &fpath); 876 if (ret < 0) { 877 pr_warning("Failed to find source file path.\n"); 878 return ret; 879 } 880 881 /* Matching lazy line pattern */ 882 ret = find_lazy_match_lines(pf->lcache, fpath, 883 pf->pev->point.lazy_line); 884 free(fpath); 885 if (ret <= 0) 886 return ret; 887 } 888 889 return die_walk_lines(sp_die, probe_point_lazy_walker, pf); 890 } 891 892 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data) 893 { 894 struct probe_finder *pf = data; 895 struct perf_probe_point *pp = &pf->pev->point; 896 Dwarf_Addr addr; 897 int ret; 898 899 if (pp->lazy_line) 900 ret = find_probe_point_lazy(in_die, pf); 901 else { 902 /* Get probe address */ 903 if (dwarf_entrypc(in_die, &addr) != 0) { 904 pr_warning("Failed to get entry address of %s.\n", 905 dwarf_diename(in_die)); 906 return -ENOENT; 907 } 908 pf->addr = addr; 909 pf->addr += pp->offset; 910 pr_debug("found inline addr: 0x%jx\n", 911 (uintmax_t)pf->addr); 912 913 ret = call_probe_finder(in_die, pf); 914 } 915 916 return ret; 917 } 918 919 /* Callback parameter with return value for libdw */ 920 struct dwarf_callback_param { 921 void *data; 922 int retval; 923 }; 924 925 /* Search function from function name */ 926 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data) 927 { 928 struct dwarf_callback_param *param = data; 929 struct probe_finder *pf = param->data; 930 struct perf_probe_point *pp = &pf->pev->point; 931 932 /* Check tag and diename */ 933 if (!die_is_func_def(sp_die) || 934 !die_match_name(sp_die, pp->function)) 935 return DWARF_CB_OK; 936 937 /* Check declared file */ 938 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die))) 939 return DWARF_CB_OK; 940 941 pr_debug("Matched function: %s\n", dwarf_diename(sp_die)); 942 pf->fname = dwarf_decl_file(sp_die); 943 if (pp->line) { /* Function relative line */ 944 dwarf_decl_line(sp_die, &pf->lno); 945 pf->lno += pp->line; 946 param->retval = find_probe_point_by_line(pf); 947 } else if (die_is_func_instance(sp_die)) { 948 /* Instances always have the entry address */ 949 dwarf_entrypc(sp_die, &pf->addr); 950 /* Real function */ 951 if (pp->lazy_line) 952 param->retval = find_probe_point_lazy(sp_die, pf); 953 else { 954 pf->addr += pp->offset; 955 /* TODO: Check the address in this function */ 956 param->retval = call_probe_finder(sp_die, pf); 957 } 958 } else if (!probe_conf.no_inlines) { 959 /* Inlined function: search instances */ 960 param->retval = die_walk_instances(sp_die, 961 probe_point_inline_cb, (void *)pf); 962 /* This could be a non-existed inline definition */ 963 if (param->retval == -ENOENT && strisglob(pp->function)) 964 param->retval = 0; 965 } 966 967 /* We need to find other candidates */ 968 if (strisglob(pp->function) && param->retval >= 0) { 969 param->retval = 0; /* We have to clear the result */ 970 return DWARF_CB_OK; 971 } 972 973 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */ 974 } 975 976 static int find_probe_point_by_func(struct probe_finder *pf) 977 { 978 struct dwarf_callback_param _param = {.data = (void *)pf, 979 .retval = 0}; 980 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0); 981 return _param.retval; 982 } 983 984 struct pubname_callback_param { 985 char *function; 986 char *file; 987 Dwarf_Die *cu_die; 988 Dwarf_Die *sp_die; 989 int found; 990 }; 991 992 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) 993 { 994 struct pubname_callback_param *param = data; 995 996 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) { 997 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram) 998 return DWARF_CB_OK; 999 1000 if (die_match_name(param->sp_die, param->function)) { 1001 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die)) 1002 return DWARF_CB_OK; 1003 1004 if (param->file && 1005 strtailcmp(param->file, dwarf_decl_file(param->sp_die))) 1006 return DWARF_CB_OK; 1007 1008 param->found = 1; 1009 return DWARF_CB_ABORT; 1010 } 1011 } 1012 1013 return DWARF_CB_OK; 1014 } 1015 1016 /* Find probe points from debuginfo */ 1017 static int debuginfo__find_probes(struct debuginfo *dbg, 1018 struct probe_finder *pf) 1019 { 1020 struct perf_probe_point *pp = &pf->pev->point; 1021 Dwarf_Off off, noff; 1022 size_t cuhl; 1023 Dwarf_Die *diep; 1024 int ret = 0; 1025 1026 #if _ELFUTILS_PREREQ(0, 142) 1027 Elf *elf; 1028 GElf_Ehdr ehdr; 1029 GElf_Shdr shdr; 1030 1031 /* Get the call frame information from this dwarf */ 1032 elf = dwarf_getelf(dbg->dbg); 1033 if (elf == NULL) 1034 return -EINVAL; 1035 1036 if (gelf_getehdr(elf, &ehdr) == NULL) 1037 return -EINVAL; 1038 1039 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) && 1040 shdr.sh_type == SHT_PROGBITS) { 1041 pf->cfi = dwarf_getcfi_elf(elf); 1042 } else { 1043 pf->cfi = dwarf_getcfi(dbg->dbg); 1044 } 1045 #endif 1046 1047 off = 0; 1048 pf->lcache = intlist__new(NULL); 1049 if (!pf->lcache) 1050 return -ENOMEM; 1051 1052 /* Fastpath: lookup by function name from .debug_pubnames section */ 1053 if (pp->function && !strisglob(pp->function)) { 1054 struct pubname_callback_param pubname_param = { 1055 .function = pp->function, 1056 .file = pp->file, 1057 .cu_die = &pf->cu_die, 1058 .sp_die = &pf->sp_die, 1059 .found = 0, 1060 }; 1061 struct dwarf_callback_param probe_param = { 1062 .data = pf, 1063 }; 1064 1065 dwarf_getpubnames(dbg->dbg, pubname_search_cb, 1066 &pubname_param, 0); 1067 if (pubname_param.found) { 1068 ret = probe_point_search_cb(&pf->sp_die, &probe_param); 1069 if (ret) 1070 goto found; 1071 } 1072 } 1073 1074 /* Loop on CUs (Compilation Unit) */ 1075 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { 1076 /* Get the DIE(Debugging Information Entry) of this CU */ 1077 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die); 1078 if (!diep) 1079 continue; 1080 1081 /* Check if target file is included. */ 1082 if (pp->file) 1083 pf->fname = cu_find_realpath(&pf->cu_die, pp->file); 1084 else 1085 pf->fname = NULL; 1086 1087 if (!pp->file || pf->fname) { 1088 if (pp->function) 1089 ret = find_probe_point_by_func(pf); 1090 else if (pp->lazy_line) 1091 ret = find_probe_point_lazy(&pf->cu_die, pf); 1092 else { 1093 pf->lno = pp->line; 1094 ret = find_probe_point_by_line(pf); 1095 } 1096 if (ret < 0) 1097 break; 1098 } 1099 off = noff; 1100 } 1101 1102 found: 1103 intlist__delete(pf->lcache); 1104 pf->lcache = NULL; 1105 1106 return ret; 1107 } 1108 1109 struct local_vars_finder { 1110 struct probe_finder *pf; 1111 struct perf_probe_arg *args; 1112 bool vars; 1113 int max_args; 1114 int nargs; 1115 int ret; 1116 }; 1117 1118 /* Collect available variables in this scope */ 1119 static int copy_variables_cb(Dwarf_Die *die_mem, void *data) 1120 { 1121 struct local_vars_finder *vf = data; 1122 struct probe_finder *pf = vf->pf; 1123 int tag; 1124 1125 tag = dwarf_tag(die_mem); 1126 if (tag == DW_TAG_formal_parameter || 1127 (tag == DW_TAG_variable && vf->vars)) { 1128 if (convert_variable_location(die_mem, vf->pf->addr, 1129 vf->pf->fb_ops, &pf->sp_die, 1130 NULL) == 0) { 1131 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem); 1132 if (vf->args[vf->nargs].var == NULL) { 1133 vf->ret = -ENOMEM; 1134 return DIE_FIND_CB_END; 1135 } 1136 pr_debug(" %s", vf->args[vf->nargs].var); 1137 vf->nargs++; 1138 } 1139 } 1140 1141 if (dwarf_haspc(die_mem, vf->pf->addr)) 1142 return DIE_FIND_CB_CONTINUE; 1143 else 1144 return DIE_FIND_CB_SIBLING; 1145 } 1146 1147 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf, 1148 struct perf_probe_arg *args) 1149 { 1150 Dwarf_Die die_mem; 1151 int i; 1152 int n = 0; 1153 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false, 1154 .max_args = MAX_PROBE_ARGS, .ret = 0}; 1155 1156 for (i = 0; i < pf->pev->nargs; i++) { 1157 /* var never be NULL */ 1158 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0) 1159 vf.vars = true; 1160 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) { 1161 /* Copy normal argument */ 1162 args[n] = pf->pev->args[i]; 1163 n++; 1164 continue; 1165 } 1166 pr_debug("Expanding %s into:", pf->pev->args[i].var); 1167 vf.nargs = n; 1168 /* Special local variables */ 1169 die_find_child(sc_die, copy_variables_cb, (void *)&vf, 1170 &die_mem); 1171 pr_debug(" (%d)\n", vf.nargs - n); 1172 if (vf.ret < 0) 1173 return vf.ret; 1174 n = vf.nargs; 1175 } 1176 return n; 1177 } 1178 1179 /* Add a found probe point into trace event list */ 1180 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf) 1181 { 1182 struct trace_event_finder *tf = 1183 container_of(pf, struct trace_event_finder, pf); 1184 struct perf_probe_point *pp = &pf->pev->point; 1185 struct probe_trace_event *tev; 1186 struct perf_probe_arg *args; 1187 int ret, i; 1188 1189 /* Check number of tevs */ 1190 if (tf->ntevs == tf->max_tevs) { 1191 pr_warning("Too many( > %d) probe point found.\n", 1192 tf->max_tevs); 1193 return -ERANGE; 1194 } 1195 tev = &tf->tevs[tf->ntevs++]; 1196 1197 /* Trace point should be converted from subprogram DIE */ 1198 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr, 1199 pp->retprobe, pp->function, &tev->point); 1200 if (ret < 0) 1201 return ret; 1202 1203 tev->point.realname = strdup(dwarf_diename(sc_die)); 1204 if (!tev->point.realname) 1205 return -ENOMEM; 1206 1207 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, 1208 tev->point.offset); 1209 1210 /* Expand special probe argument if exist */ 1211 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS); 1212 if (args == NULL) 1213 return -ENOMEM; 1214 1215 ret = expand_probe_args(sc_die, pf, args); 1216 if (ret < 0) 1217 goto end; 1218 1219 tev->nargs = ret; 1220 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); 1221 if (tev->args == NULL) { 1222 ret = -ENOMEM; 1223 goto end; 1224 } 1225 1226 /* Find each argument */ 1227 for (i = 0; i < tev->nargs; i++) { 1228 pf->pvar = &args[i]; 1229 pf->tvar = &tev->args[i]; 1230 /* Variable should be found from scope DIE */ 1231 ret = find_variable(sc_die, pf); 1232 if (ret != 0) 1233 break; 1234 } 1235 1236 end: 1237 free(args); 1238 return ret; 1239 } 1240 1241 /* Find probe_trace_events specified by perf_probe_event from debuginfo */ 1242 int debuginfo__find_trace_events(struct debuginfo *dbg, 1243 struct perf_probe_event *pev, 1244 struct probe_trace_event **tevs) 1245 { 1246 struct trace_event_finder tf = { 1247 .pf = {.pev = pev, .callback = add_probe_trace_event}, 1248 .max_tevs = probe_conf.max_probes, .mod = dbg->mod}; 1249 int ret; 1250 1251 /* Allocate result tevs array */ 1252 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs); 1253 if (*tevs == NULL) 1254 return -ENOMEM; 1255 1256 tf.tevs = *tevs; 1257 tf.ntevs = 0; 1258 1259 ret = debuginfo__find_probes(dbg, &tf.pf); 1260 if (ret < 0) { 1261 zfree(tevs); 1262 return ret; 1263 } 1264 1265 return (ret < 0) ? ret : tf.ntevs; 1266 } 1267 1268 /* Collect available variables in this scope */ 1269 static int collect_variables_cb(Dwarf_Die *die_mem, void *data) 1270 { 1271 struct available_var_finder *af = data; 1272 struct variable_list *vl; 1273 int tag, ret; 1274 1275 vl = &af->vls[af->nvls - 1]; 1276 1277 tag = dwarf_tag(die_mem); 1278 if (tag == DW_TAG_formal_parameter || 1279 tag == DW_TAG_variable) { 1280 ret = convert_variable_location(die_mem, af->pf.addr, 1281 af->pf.fb_ops, &af->pf.sp_die, 1282 NULL); 1283 if (ret == 0 || ret == -ERANGE) { 1284 int ret2; 1285 bool externs = !af->child; 1286 struct strbuf buf; 1287 1288 strbuf_init(&buf, 64); 1289 1290 if (probe_conf.show_location_range) { 1291 if (!externs) { 1292 if (ret) 1293 strbuf_addf(&buf, "[INV]\t"); 1294 else 1295 strbuf_addf(&buf, "[VAL]\t"); 1296 } else 1297 strbuf_addf(&buf, "[EXT]\t"); 1298 } 1299 1300 ret2 = die_get_varname(die_mem, &buf); 1301 1302 if (!ret2 && probe_conf.show_location_range && 1303 !externs) { 1304 strbuf_addf(&buf, "\t"); 1305 ret2 = die_get_var_range(&af->pf.sp_die, 1306 die_mem, &buf); 1307 } 1308 1309 pr_debug("Add new var: %s\n", buf.buf); 1310 if (ret2 == 0) { 1311 strlist__add(vl->vars, 1312 strbuf_detach(&buf, NULL)); 1313 } 1314 strbuf_release(&buf); 1315 } 1316 } 1317 1318 if (af->child && dwarf_haspc(die_mem, af->pf.addr)) 1319 return DIE_FIND_CB_CONTINUE; 1320 else 1321 return DIE_FIND_CB_SIBLING; 1322 } 1323 1324 /* Add a found vars into available variables list */ 1325 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) 1326 { 1327 struct available_var_finder *af = 1328 container_of(pf, struct available_var_finder, pf); 1329 struct perf_probe_point *pp = &pf->pev->point; 1330 struct variable_list *vl; 1331 Dwarf_Die die_mem; 1332 int ret; 1333 1334 /* Check number of tevs */ 1335 if (af->nvls == af->max_vls) { 1336 pr_warning("Too many( > %d) probe point found.\n", af->max_vls); 1337 return -ERANGE; 1338 } 1339 vl = &af->vls[af->nvls++]; 1340 1341 /* Trace point should be converted from subprogram DIE */ 1342 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr, 1343 pp->retprobe, pp->function, &vl->point); 1344 if (ret < 0) 1345 return ret; 1346 1347 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol, 1348 vl->point.offset); 1349 1350 /* Find local variables */ 1351 vl->vars = strlist__new(NULL, NULL); 1352 if (vl->vars == NULL) 1353 return -ENOMEM; 1354 af->child = true; 1355 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem); 1356 1357 /* Find external variables */ 1358 if (!probe_conf.show_ext_vars) 1359 goto out; 1360 /* Don't need to search child DIE for external vars. */ 1361 af->child = false; 1362 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem); 1363 1364 out: 1365 if (strlist__empty(vl->vars)) { 1366 strlist__delete(vl->vars); 1367 vl->vars = NULL; 1368 } 1369 1370 return ret; 1371 } 1372 1373 /* 1374 * Find available variables at given probe point 1375 * Return the number of found probe points. Return 0 if there is no 1376 * matched probe point. Return <0 if an error occurs. 1377 */ 1378 int debuginfo__find_available_vars_at(struct debuginfo *dbg, 1379 struct perf_probe_event *pev, 1380 struct variable_list **vls) 1381 { 1382 struct available_var_finder af = { 1383 .pf = {.pev = pev, .callback = add_available_vars}, 1384 .mod = dbg->mod, 1385 .max_vls = probe_conf.max_probes}; 1386 int ret; 1387 1388 /* Allocate result vls array */ 1389 *vls = zalloc(sizeof(struct variable_list) * af.max_vls); 1390 if (*vls == NULL) 1391 return -ENOMEM; 1392 1393 af.vls = *vls; 1394 af.nvls = 0; 1395 1396 ret = debuginfo__find_probes(dbg, &af.pf); 1397 if (ret < 0) { 1398 /* Free vlist for error */ 1399 while (af.nvls--) { 1400 zfree(&af.vls[af.nvls].point.symbol); 1401 strlist__delete(af.vls[af.nvls].vars); 1402 } 1403 zfree(vls); 1404 return ret; 1405 } 1406 1407 return (ret < 0) ? ret : af.nvls; 1408 } 1409 1410 /* For the kernel module, we need a special code to get a DIE */ 1411 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs) 1412 { 1413 int n, i; 1414 Elf32_Word shndx; 1415 Elf_Scn *scn; 1416 Elf *elf; 1417 GElf_Shdr mem, *shdr; 1418 const char *p; 1419 1420 elf = dwfl_module_getelf(dbg->mod, &dbg->bias); 1421 if (!elf) 1422 return -EINVAL; 1423 1424 /* Get the number of relocations */ 1425 n = dwfl_module_relocations(dbg->mod); 1426 if (n < 0) 1427 return -ENOENT; 1428 /* Search the relocation related .text section */ 1429 for (i = 0; i < n; i++) { 1430 p = dwfl_module_relocation_info(dbg->mod, i, &shndx); 1431 if (strcmp(p, ".text") == 0) { 1432 /* OK, get the section header */ 1433 scn = elf_getscn(elf, shndx); 1434 if (!scn) 1435 return -ENOENT; 1436 shdr = gelf_getshdr(scn, &mem); 1437 if (!shdr) 1438 return -ENOENT; 1439 *offs = shdr->sh_addr; 1440 } 1441 } 1442 return 0; 1443 } 1444 1445 /* Reverse search */ 1446 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr, 1447 struct perf_probe_point *ppt) 1448 { 1449 Dwarf_Die cudie, spdie, indie; 1450 Dwarf_Addr _addr = 0, baseaddr = 0; 1451 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp; 1452 int baseline = 0, lineno = 0, ret = 0; 1453 bool reloc = false; 1454 1455 retry: 1456 /* Find cu die */ 1457 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) { 1458 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) { 1459 addr += baseaddr; 1460 reloc = true; 1461 goto retry; 1462 } 1463 pr_warning("Failed to find debug information for address %lx\n", 1464 addr); 1465 ret = -EINVAL; 1466 goto end; 1467 } 1468 1469 /* Find a corresponding line (filename and lineno) */ 1470 cu_find_lineinfo(&cudie, addr, &fname, &lineno); 1471 /* Don't care whether it failed or not */ 1472 1473 /* Find a corresponding function (name, baseline and baseaddr) */ 1474 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) { 1475 /* Get function entry information */ 1476 func = basefunc = dwarf_diename(&spdie); 1477 if (!func || 1478 dwarf_entrypc(&spdie, &baseaddr) != 0 || 1479 dwarf_decl_line(&spdie, &baseline) != 0) { 1480 lineno = 0; 1481 goto post; 1482 } 1483 1484 fname = dwarf_decl_file(&spdie); 1485 if (addr == (unsigned long)baseaddr) { 1486 /* Function entry - Relative line number is 0 */ 1487 lineno = baseline; 1488 goto post; 1489 } 1490 1491 /* Track down the inline functions step by step */ 1492 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr, 1493 &indie)) { 1494 /* There is an inline function */ 1495 if (dwarf_entrypc(&indie, &_addr) == 0 && 1496 _addr == addr) { 1497 /* 1498 * addr is at an inline function entry. 1499 * In this case, lineno should be the call-site 1500 * line number. (overwrite lineinfo) 1501 */ 1502 lineno = die_get_call_lineno(&indie); 1503 fname = die_get_call_file(&indie); 1504 break; 1505 } else { 1506 /* 1507 * addr is in an inline function body. 1508 * Since lineno points one of the lines 1509 * of the inline function, baseline should 1510 * be the entry line of the inline function. 1511 */ 1512 tmp = dwarf_diename(&indie); 1513 if (!tmp || 1514 dwarf_decl_line(&indie, &baseline) != 0) 1515 break; 1516 func = tmp; 1517 spdie = indie; 1518 } 1519 } 1520 /* Verify the lineno and baseline are in a same file */ 1521 tmp = dwarf_decl_file(&spdie); 1522 if (!tmp || strcmp(tmp, fname) != 0) 1523 lineno = 0; 1524 } 1525 1526 post: 1527 /* Make a relative line number or an offset */ 1528 if (lineno) 1529 ppt->line = lineno - baseline; 1530 else if (basefunc) { 1531 ppt->offset = addr - (unsigned long)baseaddr; 1532 func = basefunc; 1533 } 1534 1535 /* Duplicate strings */ 1536 if (func) { 1537 ppt->function = strdup(func); 1538 if (ppt->function == NULL) { 1539 ret = -ENOMEM; 1540 goto end; 1541 } 1542 } 1543 if (fname) { 1544 ppt->file = strdup(fname); 1545 if (ppt->file == NULL) { 1546 zfree(&ppt->function); 1547 ret = -ENOMEM; 1548 goto end; 1549 } 1550 } 1551 end: 1552 if (ret == 0 && (fname || func)) 1553 ret = 1; /* Found a point */ 1554 return ret; 1555 } 1556 1557 /* Add a line and store the src path */ 1558 static int line_range_add_line(const char *src, unsigned int lineno, 1559 struct line_range *lr) 1560 { 1561 /* Copy source path */ 1562 if (!lr->path) { 1563 lr->path = strdup(src); 1564 if (lr->path == NULL) 1565 return -ENOMEM; 1566 } 1567 return intlist__add(lr->line_list, lineno); 1568 } 1569 1570 static int line_range_walk_cb(const char *fname, int lineno, 1571 Dwarf_Addr addr __maybe_unused, 1572 void *data) 1573 { 1574 struct line_finder *lf = data; 1575 int err; 1576 1577 if ((strtailcmp(fname, lf->fname) != 0) || 1578 (lf->lno_s > lineno || lf->lno_e < lineno)) 1579 return 0; 1580 1581 err = line_range_add_line(fname, lineno, lf->lr); 1582 if (err < 0 && err != -EEXIST) 1583 return err; 1584 1585 return 0; 1586 } 1587 1588 /* Find line range from its line number */ 1589 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf) 1590 { 1591 int ret; 1592 1593 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf); 1594 1595 /* Update status */ 1596 if (ret >= 0) 1597 if (!intlist__empty(lf->lr->line_list)) 1598 ret = lf->found = 1; 1599 else 1600 ret = 0; /* Lines are not found */ 1601 else { 1602 zfree(&lf->lr->path); 1603 } 1604 return ret; 1605 } 1606 1607 static int line_range_inline_cb(Dwarf_Die *in_die, void *data) 1608 { 1609 int ret = find_line_range_by_line(in_die, data); 1610 1611 /* 1612 * We have to check all instances of inlined function, because 1613 * some execution paths can be optimized out depends on the 1614 * function argument of instances. However, if an error occurs, 1615 * it should be handled by the caller. 1616 */ 1617 return ret < 0 ? ret : 0; 1618 } 1619 1620 /* Search function definition from function name */ 1621 static int line_range_search_cb(Dwarf_Die *sp_die, void *data) 1622 { 1623 struct dwarf_callback_param *param = data; 1624 struct line_finder *lf = param->data; 1625 struct line_range *lr = lf->lr; 1626 1627 /* Check declared file */ 1628 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die))) 1629 return DWARF_CB_OK; 1630 1631 if (die_is_func_def(sp_die) && 1632 die_match_name(sp_die, lr->function)) { 1633 lf->fname = dwarf_decl_file(sp_die); 1634 dwarf_decl_line(sp_die, &lr->offset); 1635 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset); 1636 lf->lno_s = lr->offset + lr->start; 1637 if (lf->lno_s < 0) /* Overflow */ 1638 lf->lno_s = INT_MAX; 1639 lf->lno_e = lr->offset + lr->end; 1640 if (lf->lno_e < 0) /* Overflow */ 1641 lf->lno_e = INT_MAX; 1642 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e); 1643 lr->start = lf->lno_s; 1644 lr->end = lf->lno_e; 1645 if (!die_is_func_instance(sp_die)) 1646 param->retval = die_walk_instances(sp_die, 1647 line_range_inline_cb, lf); 1648 else 1649 param->retval = find_line_range_by_line(sp_die, lf); 1650 return DWARF_CB_ABORT; 1651 } 1652 return DWARF_CB_OK; 1653 } 1654 1655 static int find_line_range_by_func(struct line_finder *lf) 1656 { 1657 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0}; 1658 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0); 1659 return param.retval; 1660 } 1661 1662 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr) 1663 { 1664 struct line_finder lf = {.lr = lr, .found = 0}; 1665 int ret = 0; 1666 Dwarf_Off off = 0, noff; 1667 size_t cuhl; 1668 Dwarf_Die *diep; 1669 const char *comp_dir; 1670 1671 /* Fastpath: lookup by function name from .debug_pubnames section */ 1672 if (lr->function) { 1673 struct pubname_callback_param pubname_param = { 1674 .function = lr->function, .file = lr->file, 1675 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0}; 1676 struct dwarf_callback_param line_range_param = { 1677 .data = (void *)&lf, .retval = 0}; 1678 1679 dwarf_getpubnames(dbg->dbg, pubname_search_cb, 1680 &pubname_param, 0); 1681 if (pubname_param.found) { 1682 line_range_search_cb(&lf.sp_die, &line_range_param); 1683 if (lf.found) 1684 goto found; 1685 } 1686 } 1687 1688 /* Loop on CUs (Compilation Unit) */ 1689 while (!lf.found && ret >= 0) { 1690 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, 1691 NULL, NULL, NULL) != 0) 1692 break; 1693 1694 /* Get the DIE(Debugging Information Entry) of this CU */ 1695 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die); 1696 if (!diep) 1697 continue; 1698 1699 /* Check if target file is included. */ 1700 if (lr->file) 1701 lf.fname = cu_find_realpath(&lf.cu_die, lr->file); 1702 else 1703 lf.fname = 0; 1704 1705 if (!lr->file || lf.fname) { 1706 if (lr->function) 1707 ret = find_line_range_by_func(&lf); 1708 else { 1709 lf.lno_s = lr->start; 1710 lf.lno_e = lr->end; 1711 ret = find_line_range_by_line(NULL, &lf); 1712 } 1713 } 1714 off = noff; 1715 } 1716 1717 found: 1718 /* Store comp_dir */ 1719 if (lf.found) { 1720 comp_dir = cu_get_comp_dir(&lf.cu_die); 1721 if (comp_dir) { 1722 lr->comp_dir = strdup(comp_dir); 1723 if (!lr->comp_dir) 1724 ret = -ENOMEM; 1725 } 1726 } 1727 1728 pr_debug("path: %s\n", lr->path); 1729 return (ret < 0) ? ret : lf.found; 1730 } 1731 1732 /* 1733 * Find a src file from a DWARF tag path. Prepend optional source path prefix 1734 * and chop off leading directories that do not exist. Result is passed back as 1735 * a newly allocated path on success. 1736 * Return 0 if file was found and readable, -errno otherwise. 1737 */ 1738 int get_real_path(const char *raw_path, const char *comp_dir, 1739 char **new_path) 1740 { 1741 const char *prefix = symbol_conf.source_prefix; 1742 1743 if (!prefix) { 1744 if (raw_path[0] != '/' && comp_dir) 1745 /* If not an absolute path, try to use comp_dir */ 1746 prefix = comp_dir; 1747 else { 1748 if (access(raw_path, R_OK) == 0) { 1749 *new_path = strdup(raw_path); 1750 return *new_path ? 0 : -ENOMEM; 1751 } else 1752 return -errno; 1753 } 1754 } 1755 1756 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2)); 1757 if (!*new_path) 1758 return -ENOMEM; 1759 1760 for (;;) { 1761 sprintf(*new_path, "%s/%s", prefix, raw_path); 1762 1763 if (access(*new_path, R_OK) == 0) 1764 return 0; 1765 1766 if (!symbol_conf.source_prefix) { 1767 /* In case of searching comp_dir, don't retry */ 1768 zfree(new_path); 1769 return -errno; 1770 } 1771 1772 switch (errno) { 1773 case ENAMETOOLONG: 1774 case ENOENT: 1775 case EROFS: 1776 case EFAULT: 1777 raw_path = strchr(++raw_path, '/'); 1778 if (!raw_path) { 1779 zfree(new_path); 1780 return -ENOENT; 1781 } 1782 continue; 1783 1784 default: 1785 zfree(new_path); 1786 return -errno; 1787 } 1788 } 1789 } 1790