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, *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 buf = synthesize_perf_probe_arg(pf->pvar); 567 if (!buf) 568 return -ENOMEM; 569 ptr = strchr(buf, ':'); /* Change type separator to _ */ 570 if (ptr) 571 *ptr = '_'; 572 pf->tvar->name = 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 Dwarf_Frame *frame = NULL; 658 size_t nops; 659 int ret; 660 661 if (!sc_die) { 662 pr_err("Caller must pass a scope DIE. Program error.\n"); 663 return -EINVAL; 664 } 665 666 /* If not a real subprogram, find a real one */ 667 if (!die_is_func_def(sc_die)) { 668 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { 669 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { 670 pr_warning("Ignoring tail call from %s\n", 671 dwarf_diename(&pf->sp_die)); 672 return 0; 673 } else { 674 pr_warning("Failed to find probe point in any " 675 "functions.\n"); 676 return -ENOENT; 677 } 678 } 679 } else 680 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die)); 681 682 /* Get the frame base attribute/ops from subprogram */ 683 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr); 684 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1); 685 if (ret <= 0 || nops == 0) { 686 pf->fb_ops = NULL; 687 #if _ELFUTILS_PREREQ(0, 142) 688 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa && 689 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) { 690 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 && 691 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) || 692 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) { 693 pr_warning("Failed to get call frame on 0x%jx\n", 694 (uintmax_t)pf->addr); 695 free(frame); 696 return -ENOENT; 697 } 698 #endif 699 } 700 701 /* Call finder's callback handler */ 702 ret = pf->callback(sc_die, pf); 703 704 /* Since *pf->fb_ops can be a part of frame. we should free it here. */ 705 free(frame); 706 pf->fb_ops = NULL; 707 708 return ret; 709 } 710 711 struct find_scope_param { 712 const char *function; 713 const char *file; 714 int line; 715 int diff; 716 Dwarf_Die *die_mem; 717 bool found; 718 }; 719 720 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data) 721 { 722 struct find_scope_param *fsp = data; 723 const char *file; 724 int lno; 725 726 /* Skip if declared file name does not match */ 727 if (fsp->file) { 728 file = dwarf_decl_file(fn_die); 729 if (!file || strcmp(fsp->file, file) != 0) 730 return 0; 731 } 732 /* If the function name is given, that's what user expects */ 733 if (fsp->function) { 734 if (die_match_name(fn_die, fsp->function)) { 735 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); 736 fsp->found = true; 737 return 1; 738 } 739 } else { 740 /* With the line number, find the nearest declared DIE */ 741 dwarf_decl_line(fn_die, &lno); 742 if (lno < fsp->line && fsp->diff > fsp->line - lno) { 743 /* Keep a candidate and continue */ 744 fsp->diff = fsp->line - lno; 745 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); 746 fsp->found = true; 747 } 748 } 749 return 0; 750 } 751 752 /* Find an appropriate scope fits to given conditions */ 753 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem) 754 { 755 struct find_scope_param fsp = { 756 .function = pf->pev->point.function, 757 .file = pf->fname, 758 .line = pf->lno, 759 .diff = INT_MAX, 760 .die_mem = die_mem, 761 .found = false, 762 }; 763 764 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp); 765 766 return fsp.found ? die_mem : NULL; 767 } 768 769 static int probe_point_line_walker(const char *fname, int lineno, 770 Dwarf_Addr addr, void *data) 771 { 772 struct probe_finder *pf = data; 773 Dwarf_Die *sc_die, die_mem; 774 int ret; 775 776 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0) 777 return 0; 778 779 pf->addr = addr; 780 sc_die = find_best_scope(pf, &die_mem); 781 if (!sc_die) { 782 pr_warning("Failed to find scope of probe point.\n"); 783 return -ENOENT; 784 } 785 786 ret = call_probe_finder(sc_die, pf); 787 788 /* Continue if no error, because the line will be in inline function */ 789 return ret < 0 ? ret : 0; 790 } 791 792 /* Find probe point from its line number */ 793 static int find_probe_point_by_line(struct probe_finder *pf) 794 { 795 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf); 796 } 797 798 /* Find lines which match lazy pattern */ 799 static int find_lazy_match_lines(struct intlist *list, 800 const char *fname, const char *pat) 801 { 802 FILE *fp; 803 char *line = NULL; 804 size_t line_len; 805 ssize_t len; 806 int count = 0, linenum = 1; 807 char sbuf[STRERR_BUFSIZE]; 808 809 fp = fopen(fname, "r"); 810 if (!fp) { 811 pr_warning("Failed to open %s: %s\n", fname, 812 strerror_r(errno, sbuf, sizeof(sbuf))); 813 return -errno; 814 } 815 816 while ((len = getline(&line, &line_len, fp)) > 0) { 817 818 if (line[len - 1] == '\n') 819 line[len - 1] = '\0'; 820 821 if (strlazymatch(line, pat)) { 822 intlist__add(list, linenum); 823 count++; 824 } 825 linenum++; 826 } 827 828 if (ferror(fp)) 829 count = -errno; 830 free(line); 831 fclose(fp); 832 833 if (count == 0) 834 pr_debug("No matched lines found in %s.\n", fname); 835 return count; 836 } 837 838 static int probe_point_lazy_walker(const char *fname, int lineno, 839 Dwarf_Addr addr, void *data) 840 { 841 struct probe_finder *pf = data; 842 Dwarf_Die *sc_die, die_mem; 843 int ret; 844 845 if (!intlist__has_entry(pf->lcache, lineno) || 846 strtailcmp(fname, pf->fname) != 0) 847 return 0; 848 849 pr_debug("Probe line found: line:%d addr:0x%llx\n", 850 lineno, (unsigned long long)addr); 851 pf->addr = addr; 852 pf->lno = lineno; 853 sc_die = find_best_scope(pf, &die_mem); 854 if (!sc_die) { 855 pr_warning("Failed to find scope of probe point.\n"); 856 return -ENOENT; 857 } 858 859 ret = call_probe_finder(sc_die, pf); 860 861 /* 862 * Continue if no error, because the lazy pattern will match 863 * to other lines 864 */ 865 return ret < 0 ? ret : 0; 866 } 867 868 /* Find probe points from lazy pattern */ 869 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) 870 { 871 int ret = 0; 872 char *fpath; 873 874 if (intlist__empty(pf->lcache)) { 875 const char *comp_dir; 876 877 comp_dir = cu_get_comp_dir(&pf->cu_die); 878 ret = get_real_path(pf->fname, comp_dir, &fpath); 879 if (ret < 0) { 880 pr_warning("Failed to find source file path.\n"); 881 return ret; 882 } 883 884 /* Matching lazy line pattern */ 885 ret = find_lazy_match_lines(pf->lcache, fpath, 886 pf->pev->point.lazy_line); 887 free(fpath); 888 if (ret <= 0) 889 return ret; 890 } 891 892 return die_walk_lines(sp_die, probe_point_lazy_walker, pf); 893 } 894 895 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data) 896 { 897 struct probe_finder *pf = data; 898 struct perf_probe_point *pp = &pf->pev->point; 899 Dwarf_Addr addr; 900 int ret; 901 902 if (pp->lazy_line) 903 ret = find_probe_point_lazy(in_die, pf); 904 else { 905 /* Get probe address */ 906 if (dwarf_entrypc(in_die, &addr) != 0) { 907 pr_warning("Failed to get entry address of %s.\n", 908 dwarf_diename(in_die)); 909 return -ENOENT; 910 } 911 pf->addr = addr; 912 pf->addr += pp->offset; 913 pr_debug("found inline addr: 0x%jx\n", 914 (uintmax_t)pf->addr); 915 916 ret = call_probe_finder(in_die, pf); 917 } 918 919 return ret; 920 } 921 922 /* Callback parameter with return value for libdw */ 923 struct dwarf_callback_param { 924 void *data; 925 int retval; 926 }; 927 928 /* Search function from function name */ 929 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data) 930 { 931 struct dwarf_callback_param *param = data; 932 struct probe_finder *pf = param->data; 933 struct perf_probe_point *pp = &pf->pev->point; 934 935 /* Check tag and diename */ 936 if (!die_is_func_def(sp_die) || 937 !die_match_name(sp_die, pp->function)) 938 return DWARF_CB_OK; 939 940 /* Check declared file */ 941 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die))) 942 return DWARF_CB_OK; 943 944 pr_debug("Matched function: %s\n", dwarf_diename(sp_die)); 945 pf->fname = dwarf_decl_file(sp_die); 946 if (pp->line) { /* Function relative line */ 947 dwarf_decl_line(sp_die, &pf->lno); 948 pf->lno += pp->line; 949 param->retval = find_probe_point_by_line(pf); 950 } else if (die_is_func_instance(sp_die)) { 951 /* Instances always have the entry address */ 952 dwarf_entrypc(sp_die, &pf->addr); 953 /* Real function */ 954 if (pp->lazy_line) 955 param->retval = find_probe_point_lazy(sp_die, pf); 956 else { 957 pf->addr += pp->offset; 958 /* TODO: Check the address in this function */ 959 param->retval = call_probe_finder(sp_die, pf); 960 } 961 } else if (!probe_conf.no_inlines) { 962 /* Inlined function: search instances */ 963 param->retval = die_walk_instances(sp_die, 964 probe_point_inline_cb, (void *)pf); 965 /* This could be a non-existed inline definition */ 966 if (param->retval == -ENOENT && strisglob(pp->function)) 967 param->retval = 0; 968 } 969 970 /* We need to find other candidates */ 971 if (strisglob(pp->function) && param->retval >= 0) { 972 param->retval = 0; /* We have to clear the result */ 973 return DWARF_CB_OK; 974 } 975 976 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */ 977 } 978 979 static int find_probe_point_by_func(struct probe_finder *pf) 980 { 981 struct dwarf_callback_param _param = {.data = (void *)pf, 982 .retval = 0}; 983 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0); 984 return _param.retval; 985 } 986 987 struct pubname_callback_param { 988 char *function; 989 char *file; 990 Dwarf_Die *cu_die; 991 Dwarf_Die *sp_die; 992 int found; 993 }; 994 995 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) 996 { 997 struct pubname_callback_param *param = data; 998 999 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) { 1000 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram) 1001 return DWARF_CB_OK; 1002 1003 if (die_match_name(param->sp_die, param->function)) { 1004 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die)) 1005 return DWARF_CB_OK; 1006 1007 if (param->file && 1008 strtailcmp(param->file, dwarf_decl_file(param->sp_die))) 1009 return DWARF_CB_OK; 1010 1011 param->found = 1; 1012 return DWARF_CB_ABORT; 1013 } 1014 } 1015 1016 return DWARF_CB_OK; 1017 } 1018 1019 static int debuginfo__find_probe_location(struct debuginfo *dbg, 1020 struct probe_finder *pf) 1021 { 1022 struct perf_probe_point *pp = &pf->pev->point; 1023 Dwarf_Off off, noff; 1024 size_t cuhl; 1025 Dwarf_Die *diep; 1026 int ret = 0; 1027 1028 off = 0; 1029 pf->lcache = intlist__new(NULL); 1030 if (!pf->lcache) 1031 return -ENOMEM; 1032 1033 /* Fastpath: lookup by function name from .debug_pubnames section */ 1034 if (pp->function && !strisglob(pp->function)) { 1035 struct pubname_callback_param pubname_param = { 1036 .function = pp->function, 1037 .file = pp->file, 1038 .cu_die = &pf->cu_die, 1039 .sp_die = &pf->sp_die, 1040 .found = 0, 1041 }; 1042 struct dwarf_callback_param probe_param = { 1043 .data = pf, 1044 }; 1045 1046 dwarf_getpubnames(dbg->dbg, pubname_search_cb, 1047 &pubname_param, 0); 1048 if (pubname_param.found) { 1049 ret = probe_point_search_cb(&pf->sp_die, &probe_param); 1050 if (ret) 1051 goto found; 1052 } 1053 } 1054 1055 /* Loop on CUs (Compilation Unit) */ 1056 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { 1057 /* Get the DIE(Debugging Information Entry) of this CU */ 1058 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die); 1059 if (!diep) 1060 continue; 1061 1062 /* Check if target file is included. */ 1063 if (pp->file) 1064 pf->fname = cu_find_realpath(&pf->cu_die, pp->file); 1065 else 1066 pf->fname = NULL; 1067 1068 if (!pp->file || pf->fname) { 1069 if (pp->function) 1070 ret = find_probe_point_by_func(pf); 1071 else if (pp->lazy_line) 1072 ret = find_probe_point_lazy(&pf->cu_die, pf); 1073 else { 1074 pf->lno = pp->line; 1075 ret = find_probe_point_by_line(pf); 1076 } 1077 if (ret < 0) 1078 break; 1079 } 1080 off = noff; 1081 } 1082 1083 found: 1084 intlist__delete(pf->lcache); 1085 pf->lcache = NULL; 1086 1087 return ret; 1088 } 1089 1090 /* Find probe points from debuginfo */ 1091 static int debuginfo__find_probes(struct debuginfo *dbg, 1092 struct probe_finder *pf) 1093 { 1094 int ret = 0; 1095 1096 #if _ELFUTILS_PREREQ(0, 142) 1097 Elf *elf; 1098 GElf_Ehdr ehdr; 1099 GElf_Shdr shdr; 1100 1101 if (pf->cfi_eh || pf->cfi_dbg) 1102 return debuginfo__find_probe_location(dbg, pf); 1103 1104 /* Get the call frame information from this dwarf */ 1105 elf = dwarf_getelf(dbg->dbg); 1106 if (elf == NULL) 1107 return -EINVAL; 1108 1109 if (gelf_getehdr(elf, &ehdr) == NULL) 1110 return -EINVAL; 1111 1112 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) && 1113 shdr.sh_type == SHT_PROGBITS) 1114 pf->cfi_eh = dwarf_getcfi_elf(elf); 1115 1116 pf->cfi_dbg = dwarf_getcfi(dbg->dbg); 1117 #endif 1118 1119 ret = debuginfo__find_probe_location(dbg, pf); 1120 return ret; 1121 } 1122 1123 struct local_vars_finder { 1124 struct probe_finder *pf; 1125 struct perf_probe_arg *args; 1126 bool vars; 1127 int max_args; 1128 int nargs; 1129 int ret; 1130 }; 1131 1132 /* Collect available variables in this scope */ 1133 static int copy_variables_cb(Dwarf_Die *die_mem, void *data) 1134 { 1135 struct local_vars_finder *vf = data; 1136 struct probe_finder *pf = vf->pf; 1137 int tag; 1138 1139 tag = dwarf_tag(die_mem); 1140 if (tag == DW_TAG_formal_parameter || 1141 (tag == DW_TAG_variable && vf->vars)) { 1142 if (convert_variable_location(die_mem, vf->pf->addr, 1143 vf->pf->fb_ops, &pf->sp_die, 1144 NULL) == 0) { 1145 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem); 1146 if (vf->args[vf->nargs].var == NULL) { 1147 vf->ret = -ENOMEM; 1148 return DIE_FIND_CB_END; 1149 } 1150 pr_debug(" %s", vf->args[vf->nargs].var); 1151 vf->nargs++; 1152 } 1153 } 1154 1155 if (dwarf_haspc(die_mem, vf->pf->addr)) 1156 return DIE_FIND_CB_CONTINUE; 1157 else 1158 return DIE_FIND_CB_SIBLING; 1159 } 1160 1161 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf, 1162 struct perf_probe_arg *args) 1163 { 1164 Dwarf_Die die_mem; 1165 int i; 1166 int n = 0; 1167 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false, 1168 .max_args = MAX_PROBE_ARGS, .ret = 0}; 1169 1170 for (i = 0; i < pf->pev->nargs; i++) { 1171 /* var never be NULL */ 1172 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0) 1173 vf.vars = true; 1174 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) { 1175 /* Copy normal argument */ 1176 args[n] = pf->pev->args[i]; 1177 n++; 1178 continue; 1179 } 1180 pr_debug("Expanding %s into:", pf->pev->args[i].var); 1181 vf.nargs = n; 1182 /* Special local variables */ 1183 die_find_child(sc_die, copy_variables_cb, (void *)&vf, 1184 &die_mem); 1185 pr_debug(" (%d)\n", vf.nargs - n); 1186 if (vf.ret < 0) 1187 return vf.ret; 1188 n = vf.nargs; 1189 } 1190 return n; 1191 } 1192 1193 /* Add a found probe point into trace event list */ 1194 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf) 1195 { 1196 struct trace_event_finder *tf = 1197 container_of(pf, struct trace_event_finder, pf); 1198 struct perf_probe_point *pp = &pf->pev->point; 1199 struct probe_trace_event *tev; 1200 struct perf_probe_arg *args = NULL; 1201 int ret, i; 1202 1203 /* Check number of tevs */ 1204 if (tf->ntevs == tf->max_tevs) { 1205 pr_warning("Too many( > %d) probe point found.\n", 1206 tf->max_tevs); 1207 return -ERANGE; 1208 } 1209 tev = &tf->tevs[tf->ntevs++]; 1210 1211 /* Trace point should be converted from subprogram DIE */ 1212 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr, 1213 pp->retprobe, pp->function, &tev->point); 1214 if (ret < 0) 1215 goto end; 1216 1217 tev->point.realname = strdup(dwarf_diename(sc_die)); 1218 if (!tev->point.realname) { 1219 ret = -ENOMEM; 1220 goto end; 1221 } 1222 1223 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, 1224 tev->point.offset); 1225 1226 /* Expand special probe argument if exist */ 1227 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS); 1228 if (args == NULL) { 1229 ret = -ENOMEM; 1230 goto end; 1231 } 1232 1233 ret = expand_probe_args(sc_die, pf, args); 1234 if (ret < 0) 1235 goto end; 1236 1237 tev->nargs = ret; 1238 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); 1239 if (tev->args == NULL) { 1240 ret = -ENOMEM; 1241 goto end; 1242 } 1243 1244 /* Find each argument */ 1245 for (i = 0; i < tev->nargs; i++) { 1246 pf->pvar = &args[i]; 1247 pf->tvar = &tev->args[i]; 1248 /* Variable should be found from scope DIE */ 1249 ret = find_variable(sc_die, pf); 1250 if (ret != 0) 1251 break; 1252 } 1253 1254 end: 1255 if (ret) { 1256 clear_probe_trace_event(tev); 1257 tf->ntevs--; 1258 } 1259 free(args); 1260 return ret; 1261 } 1262 1263 /* Find probe_trace_events specified by perf_probe_event from debuginfo */ 1264 int debuginfo__find_trace_events(struct debuginfo *dbg, 1265 struct perf_probe_event *pev, 1266 struct probe_trace_event **tevs) 1267 { 1268 struct trace_event_finder tf = { 1269 .pf = {.pev = pev, .callback = add_probe_trace_event}, 1270 .max_tevs = probe_conf.max_probes, .mod = dbg->mod}; 1271 int ret, i; 1272 1273 /* Allocate result tevs array */ 1274 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs); 1275 if (*tevs == NULL) 1276 return -ENOMEM; 1277 1278 tf.tevs = *tevs; 1279 tf.ntevs = 0; 1280 1281 ret = debuginfo__find_probes(dbg, &tf.pf); 1282 if (ret < 0) { 1283 for (i = 0; i < tf.ntevs; i++) 1284 clear_probe_trace_event(&tf.tevs[i]); 1285 zfree(tevs); 1286 return ret; 1287 } 1288 1289 return (ret < 0) ? ret : tf.ntevs; 1290 } 1291 1292 /* Collect available variables in this scope */ 1293 static int collect_variables_cb(Dwarf_Die *die_mem, void *data) 1294 { 1295 struct available_var_finder *af = data; 1296 struct variable_list *vl; 1297 struct strbuf buf = STRBUF_INIT; 1298 int tag, ret; 1299 1300 vl = &af->vls[af->nvls - 1]; 1301 1302 tag = dwarf_tag(die_mem); 1303 if (tag == DW_TAG_formal_parameter || 1304 tag == DW_TAG_variable) { 1305 ret = convert_variable_location(die_mem, af->pf.addr, 1306 af->pf.fb_ops, &af->pf.sp_die, 1307 NULL); 1308 if (ret == 0 || ret == -ERANGE) { 1309 int ret2; 1310 bool externs = !af->child; 1311 1312 if (strbuf_init(&buf, 64) < 0) 1313 goto error; 1314 1315 if (probe_conf.show_location_range) { 1316 if (!externs) 1317 ret2 = strbuf_add(&buf, 1318 ret ? "[INV]\t" : "[VAL]\t", 6); 1319 else 1320 ret2 = strbuf_add(&buf, "[EXT]\t", 6); 1321 if (ret2) 1322 goto error; 1323 } 1324 1325 ret2 = die_get_varname(die_mem, &buf); 1326 1327 if (!ret2 && probe_conf.show_location_range && 1328 !externs) { 1329 if (strbuf_addch(&buf, '\t') < 0) 1330 goto error; 1331 ret2 = die_get_var_range(&af->pf.sp_die, 1332 die_mem, &buf); 1333 } 1334 1335 pr_debug("Add new var: %s\n", buf.buf); 1336 if (ret2 == 0) { 1337 strlist__add(vl->vars, 1338 strbuf_detach(&buf, NULL)); 1339 } 1340 strbuf_release(&buf); 1341 } 1342 } 1343 1344 if (af->child && dwarf_haspc(die_mem, af->pf.addr)) 1345 return DIE_FIND_CB_CONTINUE; 1346 else 1347 return DIE_FIND_CB_SIBLING; 1348 error: 1349 strbuf_release(&buf); 1350 pr_debug("Error in strbuf\n"); 1351 return DIE_FIND_CB_END; 1352 } 1353 1354 /* Add a found vars into available variables list */ 1355 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) 1356 { 1357 struct available_var_finder *af = 1358 container_of(pf, struct available_var_finder, pf); 1359 struct perf_probe_point *pp = &pf->pev->point; 1360 struct variable_list *vl; 1361 Dwarf_Die die_mem; 1362 int ret; 1363 1364 /* Check number of tevs */ 1365 if (af->nvls == af->max_vls) { 1366 pr_warning("Too many( > %d) probe point found.\n", af->max_vls); 1367 return -ERANGE; 1368 } 1369 vl = &af->vls[af->nvls++]; 1370 1371 /* Trace point should be converted from subprogram DIE */ 1372 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr, 1373 pp->retprobe, pp->function, &vl->point); 1374 if (ret < 0) 1375 return ret; 1376 1377 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol, 1378 vl->point.offset); 1379 1380 /* Find local variables */ 1381 vl->vars = strlist__new(NULL, NULL); 1382 if (vl->vars == NULL) 1383 return -ENOMEM; 1384 af->child = true; 1385 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem); 1386 1387 /* Find external variables */ 1388 if (!probe_conf.show_ext_vars) 1389 goto out; 1390 /* Don't need to search child DIE for external vars. */ 1391 af->child = false; 1392 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem); 1393 1394 out: 1395 if (strlist__empty(vl->vars)) { 1396 strlist__delete(vl->vars); 1397 vl->vars = NULL; 1398 } 1399 1400 return ret; 1401 } 1402 1403 /* 1404 * Find available variables at given probe point 1405 * Return the number of found probe points. Return 0 if there is no 1406 * matched probe point. Return <0 if an error occurs. 1407 */ 1408 int debuginfo__find_available_vars_at(struct debuginfo *dbg, 1409 struct perf_probe_event *pev, 1410 struct variable_list **vls) 1411 { 1412 struct available_var_finder af = { 1413 .pf = {.pev = pev, .callback = add_available_vars}, 1414 .mod = dbg->mod, 1415 .max_vls = probe_conf.max_probes}; 1416 int ret; 1417 1418 /* Allocate result vls array */ 1419 *vls = zalloc(sizeof(struct variable_list) * af.max_vls); 1420 if (*vls == NULL) 1421 return -ENOMEM; 1422 1423 af.vls = *vls; 1424 af.nvls = 0; 1425 1426 ret = debuginfo__find_probes(dbg, &af.pf); 1427 if (ret < 0) { 1428 /* Free vlist for error */ 1429 while (af.nvls--) { 1430 zfree(&af.vls[af.nvls].point.symbol); 1431 strlist__delete(af.vls[af.nvls].vars); 1432 } 1433 zfree(vls); 1434 return ret; 1435 } 1436 1437 return (ret < 0) ? ret : af.nvls; 1438 } 1439 1440 /* For the kernel module, we need a special code to get a DIE */ 1441 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs) 1442 { 1443 int n, i; 1444 Elf32_Word shndx; 1445 Elf_Scn *scn; 1446 Elf *elf; 1447 GElf_Shdr mem, *shdr; 1448 const char *p; 1449 1450 elf = dwfl_module_getelf(dbg->mod, &dbg->bias); 1451 if (!elf) 1452 return -EINVAL; 1453 1454 /* Get the number of relocations */ 1455 n = dwfl_module_relocations(dbg->mod); 1456 if (n < 0) 1457 return -ENOENT; 1458 /* Search the relocation related .text section */ 1459 for (i = 0; i < n; i++) { 1460 p = dwfl_module_relocation_info(dbg->mod, i, &shndx); 1461 if (strcmp(p, ".text") == 0) { 1462 /* OK, get the section header */ 1463 scn = elf_getscn(elf, shndx); 1464 if (!scn) 1465 return -ENOENT; 1466 shdr = gelf_getshdr(scn, &mem); 1467 if (!shdr) 1468 return -ENOENT; 1469 *offs = shdr->sh_addr; 1470 } 1471 } 1472 return 0; 1473 } 1474 1475 /* Reverse search */ 1476 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr, 1477 struct perf_probe_point *ppt) 1478 { 1479 Dwarf_Die cudie, spdie, indie; 1480 Dwarf_Addr _addr = 0, baseaddr = 0; 1481 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp; 1482 int baseline = 0, lineno = 0, ret = 0; 1483 bool reloc = false; 1484 1485 retry: 1486 /* Find cu die */ 1487 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) { 1488 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) { 1489 addr += baseaddr; 1490 reloc = true; 1491 goto retry; 1492 } 1493 pr_warning("Failed to find debug information for address %lx\n", 1494 addr); 1495 ret = -EINVAL; 1496 goto end; 1497 } 1498 1499 /* Find a corresponding line (filename and lineno) */ 1500 cu_find_lineinfo(&cudie, addr, &fname, &lineno); 1501 /* Don't care whether it failed or not */ 1502 1503 /* Find a corresponding function (name, baseline and baseaddr) */ 1504 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) { 1505 /* Get function entry information */ 1506 func = basefunc = dwarf_diename(&spdie); 1507 if (!func || 1508 dwarf_entrypc(&spdie, &baseaddr) != 0 || 1509 dwarf_decl_line(&spdie, &baseline) != 0) { 1510 lineno = 0; 1511 goto post; 1512 } 1513 1514 fname = dwarf_decl_file(&spdie); 1515 if (addr == (unsigned long)baseaddr) { 1516 /* Function entry - Relative line number is 0 */ 1517 lineno = baseline; 1518 goto post; 1519 } 1520 1521 /* Track down the inline functions step by step */ 1522 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr, 1523 &indie)) { 1524 /* There is an inline function */ 1525 if (dwarf_entrypc(&indie, &_addr) == 0 && 1526 _addr == addr) { 1527 /* 1528 * addr is at an inline function entry. 1529 * In this case, lineno should be the call-site 1530 * line number. (overwrite lineinfo) 1531 */ 1532 lineno = die_get_call_lineno(&indie); 1533 fname = die_get_call_file(&indie); 1534 break; 1535 } else { 1536 /* 1537 * addr is in an inline function body. 1538 * Since lineno points one of the lines 1539 * of the inline function, baseline should 1540 * be the entry line of the inline function. 1541 */ 1542 tmp = dwarf_diename(&indie); 1543 if (!tmp || 1544 dwarf_decl_line(&indie, &baseline) != 0) 1545 break; 1546 func = tmp; 1547 spdie = indie; 1548 } 1549 } 1550 /* Verify the lineno and baseline are in a same file */ 1551 tmp = dwarf_decl_file(&spdie); 1552 if (!tmp || strcmp(tmp, fname) != 0) 1553 lineno = 0; 1554 } 1555 1556 post: 1557 /* Make a relative line number or an offset */ 1558 if (lineno) 1559 ppt->line = lineno - baseline; 1560 else if (basefunc) { 1561 ppt->offset = addr - (unsigned long)baseaddr; 1562 func = basefunc; 1563 } 1564 1565 /* Duplicate strings */ 1566 if (func) { 1567 ppt->function = strdup(func); 1568 if (ppt->function == NULL) { 1569 ret = -ENOMEM; 1570 goto end; 1571 } 1572 } 1573 if (fname) { 1574 ppt->file = strdup(fname); 1575 if (ppt->file == NULL) { 1576 zfree(&ppt->function); 1577 ret = -ENOMEM; 1578 goto end; 1579 } 1580 } 1581 end: 1582 if (ret == 0 && (fname || func)) 1583 ret = 1; /* Found a point */ 1584 return ret; 1585 } 1586 1587 /* Add a line and store the src path */ 1588 static int line_range_add_line(const char *src, unsigned int lineno, 1589 struct line_range *lr) 1590 { 1591 /* Copy source path */ 1592 if (!lr->path) { 1593 lr->path = strdup(src); 1594 if (lr->path == NULL) 1595 return -ENOMEM; 1596 } 1597 return intlist__add(lr->line_list, lineno); 1598 } 1599 1600 static int line_range_walk_cb(const char *fname, int lineno, 1601 Dwarf_Addr addr __maybe_unused, 1602 void *data) 1603 { 1604 struct line_finder *lf = data; 1605 int err; 1606 1607 if ((strtailcmp(fname, lf->fname) != 0) || 1608 (lf->lno_s > lineno || lf->lno_e < lineno)) 1609 return 0; 1610 1611 err = line_range_add_line(fname, lineno, lf->lr); 1612 if (err < 0 && err != -EEXIST) 1613 return err; 1614 1615 return 0; 1616 } 1617 1618 /* Find line range from its line number */ 1619 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf) 1620 { 1621 int ret; 1622 1623 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf); 1624 1625 /* Update status */ 1626 if (ret >= 0) 1627 if (!intlist__empty(lf->lr->line_list)) 1628 ret = lf->found = 1; 1629 else 1630 ret = 0; /* Lines are not found */ 1631 else { 1632 zfree(&lf->lr->path); 1633 } 1634 return ret; 1635 } 1636 1637 static int line_range_inline_cb(Dwarf_Die *in_die, void *data) 1638 { 1639 int ret = find_line_range_by_line(in_die, data); 1640 1641 /* 1642 * We have to check all instances of inlined function, because 1643 * some execution paths can be optimized out depends on the 1644 * function argument of instances. However, if an error occurs, 1645 * it should be handled by the caller. 1646 */ 1647 return ret < 0 ? ret : 0; 1648 } 1649 1650 /* Search function definition from function name */ 1651 static int line_range_search_cb(Dwarf_Die *sp_die, void *data) 1652 { 1653 struct dwarf_callback_param *param = data; 1654 struct line_finder *lf = param->data; 1655 struct line_range *lr = lf->lr; 1656 1657 /* Check declared file */ 1658 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die))) 1659 return DWARF_CB_OK; 1660 1661 if (die_is_func_def(sp_die) && 1662 die_match_name(sp_die, lr->function)) { 1663 lf->fname = dwarf_decl_file(sp_die); 1664 dwarf_decl_line(sp_die, &lr->offset); 1665 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset); 1666 lf->lno_s = lr->offset + lr->start; 1667 if (lf->lno_s < 0) /* Overflow */ 1668 lf->lno_s = INT_MAX; 1669 lf->lno_e = lr->offset + lr->end; 1670 if (lf->lno_e < 0) /* Overflow */ 1671 lf->lno_e = INT_MAX; 1672 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e); 1673 lr->start = lf->lno_s; 1674 lr->end = lf->lno_e; 1675 if (!die_is_func_instance(sp_die)) 1676 param->retval = die_walk_instances(sp_die, 1677 line_range_inline_cb, lf); 1678 else 1679 param->retval = find_line_range_by_line(sp_die, lf); 1680 return DWARF_CB_ABORT; 1681 } 1682 return DWARF_CB_OK; 1683 } 1684 1685 static int find_line_range_by_func(struct line_finder *lf) 1686 { 1687 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0}; 1688 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0); 1689 return param.retval; 1690 } 1691 1692 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr) 1693 { 1694 struct line_finder lf = {.lr = lr, .found = 0}; 1695 int ret = 0; 1696 Dwarf_Off off = 0, noff; 1697 size_t cuhl; 1698 Dwarf_Die *diep; 1699 const char *comp_dir; 1700 1701 /* Fastpath: lookup by function name from .debug_pubnames section */ 1702 if (lr->function) { 1703 struct pubname_callback_param pubname_param = { 1704 .function = lr->function, .file = lr->file, 1705 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0}; 1706 struct dwarf_callback_param line_range_param = { 1707 .data = (void *)&lf, .retval = 0}; 1708 1709 dwarf_getpubnames(dbg->dbg, pubname_search_cb, 1710 &pubname_param, 0); 1711 if (pubname_param.found) { 1712 line_range_search_cb(&lf.sp_die, &line_range_param); 1713 if (lf.found) 1714 goto found; 1715 } 1716 } 1717 1718 /* Loop on CUs (Compilation Unit) */ 1719 while (!lf.found && ret >= 0) { 1720 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, 1721 NULL, NULL, NULL) != 0) 1722 break; 1723 1724 /* Get the DIE(Debugging Information Entry) of this CU */ 1725 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die); 1726 if (!diep) 1727 continue; 1728 1729 /* Check if target file is included. */ 1730 if (lr->file) 1731 lf.fname = cu_find_realpath(&lf.cu_die, lr->file); 1732 else 1733 lf.fname = 0; 1734 1735 if (!lr->file || lf.fname) { 1736 if (lr->function) 1737 ret = find_line_range_by_func(&lf); 1738 else { 1739 lf.lno_s = lr->start; 1740 lf.lno_e = lr->end; 1741 ret = find_line_range_by_line(NULL, &lf); 1742 } 1743 } 1744 off = noff; 1745 } 1746 1747 found: 1748 /* Store comp_dir */ 1749 if (lf.found) { 1750 comp_dir = cu_get_comp_dir(&lf.cu_die); 1751 if (comp_dir) { 1752 lr->comp_dir = strdup(comp_dir); 1753 if (!lr->comp_dir) 1754 ret = -ENOMEM; 1755 } 1756 } 1757 1758 pr_debug("path: %s\n", lr->path); 1759 return (ret < 0) ? ret : lf.found; 1760 } 1761 1762 /* 1763 * Find a src file from a DWARF tag path. Prepend optional source path prefix 1764 * and chop off leading directories that do not exist. Result is passed back as 1765 * a newly allocated path on success. 1766 * Return 0 if file was found and readable, -errno otherwise. 1767 */ 1768 int get_real_path(const char *raw_path, const char *comp_dir, 1769 char **new_path) 1770 { 1771 const char *prefix = symbol_conf.source_prefix; 1772 1773 if (!prefix) { 1774 if (raw_path[0] != '/' && comp_dir) 1775 /* If not an absolute path, try to use comp_dir */ 1776 prefix = comp_dir; 1777 else { 1778 if (access(raw_path, R_OK) == 0) { 1779 *new_path = strdup(raw_path); 1780 return *new_path ? 0 : -ENOMEM; 1781 } else 1782 return -errno; 1783 } 1784 } 1785 1786 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2)); 1787 if (!*new_path) 1788 return -ENOMEM; 1789 1790 for (;;) { 1791 sprintf(*new_path, "%s/%s", prefix, raw_path); 1792 1793 if (access(*new_path, R_OK) == 0) 1794 return 0; 1795 1796 if (!symbol_conf.source_prefix) { 1797 /* In case of searching comp_dir, don't retry */ 1798 zfree(new_path); 1799 return -errno; 1800 } 1801 1802 switch (errno) { 1803 case ENAMETOOLONG: 1804 case ENOENT: 1805 case EROFS: 1806 case EFAULT: 1807 raw_path = strchr(++raw_path, '/'); 1808 if (!raw_path) { 1809 zfree(new_path); 1810 return -ENOENT; 1811 } 1812 continue; 1813 1814 default: 1815 zfree(new_path); 1816 return -errno; 1817 } 1818 } 1819 } 1820