1 // SPDX-License-Identifier: GPL-2.0 2 #include <fcntl.h> 3 #include <stdio.h> 4 #include <errno.h> 5 #include <stdlib.h> 6 #include <string.h> 7 #include <unistd.h> 8 #include <inttypes.h> 9 10 #include "dso.h" 11 #include "map.h" 12 #include "maps.h" 13 #include "symbol.h" 14 #include "symsrc.h" 15 #include "demangle-ocaml.h" 16 #include "demangle-java.h" 17 #include "demangle-rust.h" 18 #include "machine.h" 19 #include "vdso.h" 20 #include "debug.h" 21 #include "util/copyfile.h" 22 #include <linux/ctype.h> 23 #include <linux/kernel.h> 24 #include <linux/zalloc.h> 25 #include <symbol/kallsyms.h> 26 #include <internal/lib.h> 27 28 #ifndef EM_AARCH64 29 #define EM_AARCH64 183 /* ARM 64 bit */ 30 #endif 31 32 #ifndef ELF32_ST_VISIBILITY 33 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03) 34 #endif 35 36 /* For ELF64 the definitions are the same. */ 37 #ifndef ELF64_ST_VISIBILITY 38 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o) 39 #endif 40 41 /* How to extract information held in the st_other field. */ 42 #ifndef GELF_ST_VISIBILITY 43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val) 44 #endif 45 46 typedef Elf64_Nhdr GElf_Nhdr; 47 48 #ifndef DMGL_PARAMS 49 #define DMGL_NO_OPTS 0 /* For readability... */ 50 #define DMGL_PARAMS (1 << 0) /* Include function args */ 51 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ 52 #endif 53 54 #ifdef HAVE_LIBBFD_SUPPORT 55 #define PACKAGE 'perf' 56 #include <bfd.h> 57 #else 58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT 59 extern char *cplus_demangle(const char *, int); 60 61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i) 62 { 63 return cplus_demangle(c, i); 64 } 65 #else 66 #ifdef NO_DEMANGLE 67 static inline char *bfd_demangle(void __maybe_unused *v, 68 const char __maybe_unused *c, 69 int __maybe_unused i) 70 { 71 return NULL; 72 } 73 #endif 74 #endif 75 #endif 76 77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT 78 static int elf_getphdrnum(Elf *elf, size_t *dst) 79 { 80 GElf_Ehdr gehdr; 81 GElf_Ehdr *ehdr; 82 83 ehdr = gelf_getehdr(elf, &gehdr); 84 if (!ehdr) 85 return -1; 86 87 *dst = ehdr->e_phnum; 88 89 return 0; 90 } 91 #endif 92 93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT 94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused) 95 { 96 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__); 97 return -1; 98 } 99 #endif 100 101 #ifndef NT_GNU_BUILD_ID 102 #define NT_GNU_BUILD_ID 3 103 #endif 104 105 /** 106 * elf_symtab__for_each_symbol - iterate thru all the symbols 107 * 108 * @syms: struct elf_symtab instance to iterate 109 * @idx: uint32_t idx 110 * @sym: GElf_Sym iterator 111 */ 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \ 113 for (idx = 0, gelf_getsym(syms, idx, &sym);\ 114 idx < nr_syms; \ 115 idx++, gelf_getsym(syms, idx, &sym)) 116 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym) 118 { 119 return GELF_ST_TYPE(sym->st_info); 120 } 121 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym) 123 { 124 return GELF_ST_VISIBILITY(sym->st_other); 125 } 126 127 #ifndef STT_GNU_IFUNC 128 #define STT_GNU_IFUNC 10 129 #endif 130 131 static inline int elf_sym__is_function(const GElf_Sym *sym) 132 { 133 return (elf_sym__type(sym) == STT_FUNC || 134 elf_sym__type(sym) == STT_GNU_IFUNC) && 135 sym->st_name != 0 && 136 sym->st_shndx != SHN_UNDEF; 137 } 138 139 static inline bool elf_sym__is_object(const GElf_Sym *sym) 140 { 141 return elf_sym__type(sym) == STT_OBJECT && 142 sym->st_name != 0 && 143 sym->st_shndx != SHN_UNDEF; 144 } 145 146 static inline int elf_sym__is_label(const GElf_Sym *sym) 147 { 148 return elf_sym__type(sym) == STT_NOTYPE && 149 sym->st_name != 0 && 150 sym->st_shndx != SHN_UNDEF && 151 sym->st_shndx != SHN_ABS && 152 elf_sym__visibility(sym) != STV_HIDDEN && 153 elf_sym__visibility(sym) != STV_INTERNAL; 154 } 155 156 static bool elf_sym__filter(GElf_Sym *sym) 157 { 158 return elf_sym__is_function(sym) || elf_sym__is_object(sym); 159 } 160 161 static inline const char *elf_sym__name(const GElf_Sym *sym, 162 const Elf_Data *symstrs) 163 { 164 return symstrs->d_buf + sym->st_name; 165 } 166 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr, 168 const Elf_Data *secstrs) 169 { 170 return secstrs->d_buf + shdr->sh_name; 171 } 172 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr, 174 const Elf_Data *secstrs) 175 { 176 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL; 177 } 178 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr, 180 const Elf_Data *secstrs) 181 { 182 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL; 183 } 184 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs) 186 { 187 return elf_sec__is_text(shdr, secstrs) || 188 elf_sec__is_data(shdr, secstrs); 189 } 190 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) 192 { 193 Elf_Scn *sec = NULL; 194 GElf_Shdr shdr; 195 size_t cnt = 1; 196 197 while ((sec = elf_nextscn(elf, sec)) != NULL) { 198 gelf_getshdr(sec, &shdr); 199 200 if ((addr >= shdr.sh_addr) && 201 (addr < (shdr.sh_addr + shdr.sh_size))) 202 return cnt; 203 204 ++cnt; 205 } 206 207 return -1; 208 } 209 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, 211 GElf_Shdr *shp, const char *name, size_t *idx) 212 { 213 Elf_Scn *sec = NULL; 214 size_t cnt = 1; 215 216 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 217 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) 218 return NULL; 219 220 while ((sec = elf_nextscn(elf, sec)) != NULL) { 221 char *str; 222 223 gelf_getshdr(sec, shp); 224 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); 225 if (str && !strcmp(name, str)) { 226 if (idx) 227 *idx = cnt; 228 return sec; 229 } 230 ++cnt; 231 } 232 233 return NULL; 234 } 235 236 static bool want_demangle(bool is_kernel_sym) 237 { 238 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle; 239 } 240 241 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 242 { 243 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS; 244 char *demangled = NULL; 245 246 /* 247 * We need to figure out if the object was created from C++ sources 248 * DWARF DW_compile_unit has this, but we don't always have access 249 * to it... 250 */ 251 if (!want_demangle(dso->kernel || kmodule)) 252 return demangled; 253 254 demangled = bfd_demangle(NULL, elf_name, demangle_flags); 255 if (demangled == NULL) { 256 demangled = ocaml_demangle_sym(elf_name); 257 if (demangled == NULL) { 258 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET); 259 } 260 } 261 else if (rust_is_mangled(demangled)) 262 /* 263 * Input to Rust demangling is the BFD-demangled 264 * name which it Rust-demangles in place. 265 */ 266 rust_demangle_sym(demangled); 267 268 return demangled; 269 } 270 271 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \ 272 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \ 273 idx < nr_entries; \ 274 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem)) 275 276 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \ 277 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \ 278 idx < nr_entries; \ 279 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem)) 280 281 /* 282 * We need to check if we have a .dynsym, so that we can handle the 283 * .plt, synthesizing its symbols, that aren't on the symtabs (be it 284 * .dynsym or .symtab). 285 * And always look at the original dso, not at debuginfo packages, that 286 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS). 287 */ 288 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) 289 { 290 uint32_t nr_rel_entries, idx; 291 GElf_Sym sym; 292 u64 plt_offset, plt_header_size, plt_entry_size; 293 GElf_Shdr shdr_plt; 294 struct symbol *f; 295 GElf_Shdr shdr_rel_plt, shdr_dynsym; 296 Elf_Data *reldata, *syms, *symstrs; 297 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym; 298 size_t dynsym_idx; 299 GElf_Ehdr ehdr; 300 char sympltname[1024]; 301 Elf *elf; 302 int nr = 0, symidx, err = 0; 303 304 if (!ss->dynsym) 305 return 0; 306 307 elf = ss->elf; 308 ehdr = ss->ehdr; 309 310 scn_dynsym = ss->dynsym; 311 shdr_dynsym = ss->dynshdr; 312 dynsym_idx = ss->dynsym_idx; 313 314 if (scn_dynsym == NULL) 315 goto out_elf_end; 316 317 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 318 ".rela.plt", NULL); 319 if (scn_plt_rel == NULL) { 320 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 321 ".rel.plt", NULL); 322 if (scn_plt_rel == NULL) 323 goto out_elf_end; 324 } 325 326 err = -1; 327 328 if (shdr_rel_plt.sh_link != dynsym_idx) 329 goto out_elf_end; 330 331 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL) 332 goto out_elf_end; 333 334 /* 335 * Fetch the relocation section to find the idxes to the GOT 336 * and the symbols in the .dynsym they refer to. 337 */ 338 reldata = elf_getdata(scn_plt_rel, NULL); 339 if (reldata == NULL) 340 goto out_elf_end; 341 342 syms = elf_getdata(scn_dynsym, NULL); 343 if (syms == NULL) 344 goto out_elf_end; 345 346 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link); 347 if (scn_symstrs == NULL) 348 goto out_elf_end; 349 350 symstrs = elf_getdata(scn_symstrs, NULL); 351 if (symstrs == NULL) 352 goto out_elf_end; 353 354 if (symstrs->d_size == 0) 355 goto out_elf_end; 356 357 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; 358 plt_offset = shdr_plt.sh_offset; 359 switch (ehdr.e_machine) { 360 case EM_ARM: 361 plt_header_size = 20; 362 plt_entry_size = 12; 363 break; 364 365 case EM_AARCH64: 366 plt_header_size = 32; 367 plt_entry_size = 16; 368 break; 369 370 case EM_SPARC: 371 plt_header_size = 48; 372 plt_entry_size = 12; 373 break; 374 375 case EM_SPARCV9: 376 plt_header_size = 128; 377 plt_entry_size = 32; 378 break; 379 380 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */ 381 plt_header_size = shdr_plt.sh_entsize; 382 plt_entry_size = shdr_plt.sh_entsize; 383 break; 384 } 385 plt_offset += plt_header_size; 386 387 if (shdr_rel_plt.sh_type == SHT_RELA) { 388 GElf_Rela pos_mem, *pos; 389 390 elf_section__for_each_rela(reldata, pos, pos_mem, idx, 391 nr_rel_entries) { 392 const char *elf_name = NULL; 393 char *demangled = NULL; 394 symidx = GELF_R_SYM(pos->r_info); 395 gelf_getsym(syms, symidx, &sym); 396 397 elf_name = elf_sym__name(&sym, symstrs); 398 demangled = demangle_sym(dso, 0, elf_name); 399 if (demangled != NULL) 400 elf_name = demangled; 401 snprintf(sympltname, sizeof(sympltname), 402 "%s@plt", elf_name); 403 free(demangled); 404 405 f = symbol__new(plt_offset, plt_entry_size, 406 STB_GLOBAL, STT_FUNC, sympltname); 407 if (!f) 408 goto out_elf_end; 409 410 plt_offset += plt_entry_size; 411 symbols__insert(&dso->symbols, f); 412 ++nr; 413 } 414 } else if (shdr_rel_plt.sh_type == SHT_REL) { 415 GElf_Rel pos_mem, *pos; 416 elf_section__for_each_rel(reldata, pos, pos_mem, idx, 417 nr_rel_entries) { 418 const char *elf_name = NULL; 419 char *demangled = NULL; 420 symidx = GELF_R_SYM(pos->r_info); 421 gelf_getsym(syms, symidx, &sym); 422 423 elf_name = elf_sym__name(&sym, symstrs); 424 demangled = demangle_sym(dso, 0, elf_name); 425 if (demangled != NULL) 426 elf_name = demangled; 427 snprintf(sympltname, sizeof(sympltname), 428 "%s@plt", elf_name); 429 free(demangled); 430 431 f = symbol__new(plt_offset, plt_entry_size, 432 STB_GLOBAL, STT_FUNC, sympltname); 433 if (!f) 434 goto out_elf_end; 435 436 plt_offset += plt_entry_size; 437 symbols__insert(&dso->symbols, f); 438 ++nr; 439 } 440 } 441 442 err = 0; 443 out_elf_end: 444 if (err == 0) 445 return nr; 446 pr_debug("%s: problems reading %s PLT info.\n", 447 __func__, dso->long_name); 448 return 0; 449 } 450 451 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 452 { 453 return demangle_sym(dso, kmodule, elf_name); 454 } 455 456 /* 457 * Align offset to 4 bytes as needed for note name and descriptor data. 458 */ 459 #define NOTE_ALIGN(n) (((n) + 3) & -4U) 460 461 static int elf_read_build_id(Elf *elf, void *bf, size_t size) 462 { 463 int err = -1; 464 GElf_Ehdr ehdr; 465 GElf_Shdr shdr; 466 Elf_Data *data; 467 Elf_Scn *sec; 468 Elf_Kind ek; 469 void *ptr; 470 471 if (size < BUILD_ID_SIZE) 472 goto out; 473 474 ek = elf_kind(elf); 475 if (ek != ELF_K_ELF) 476 goto out; 477 478 if (gelf_getehdr(elf, &ehdr) == NULL) { 479 pr_err("%s: cannot get elf header.\n", __func__); 480 goto out; 481 } 482 483 /* 484 * Check following sections for notes: 485 * '.note.gnu.build-id' 486 * '.notes' 487 * '.note' (VDSO specific) 488 */ 489 do { 490 sec = elf_section_by_name(elf, &ehdr, &shdr, 491 ".note.gnu.build-id", NULL); 492 if (sec) 493 break; 494 495 sec = elf_section_by_name(elf, &ehdr, &shdr, 496 ".notes", NULL); 497 if (sec) 498 break; 499 500 sec = elf_section_by_name(elf, &ehdr, &shdr, 501 ".note", NULL); 502 if (sec) 503 break; 504 505 return err; 506 507 } while (0); 508 509 data = elf_getdata(sec, NULL); 510 if (data == NULL) 511 goto out; 512 513 ptr = data->d_buf; 514 while (ptr < (data->d_buf + data->d_size)) { 515 GElf_Nhdr *nhdr = ptr; 516 size_t namesz = NOTE_ALIGN(nhdr->n_namesz), 517 descsz = NOTE_ALIGN(nhdr->n_descsz); 518 const char *name; 519 520 ptr += sizeof(*nhdr); 521 name = ptr; 522 ptr += namesz; 523 if (nhdr->n_type == NT_GNU_BUILD_ID && 524 nhdr->n_namesz == sizeof("GNU")) { 525 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 526 size_t sz = min(size, descsz); 527 memcpy(bf, ptr, sz); 528 memset(bf + sz, 0, size - sz); 529 err = descsz; 530 break; 531 } 532 } 533 ptr += descsz; 534 } 535 536 out: 537 return err; 538 } 539 540 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT 541 542 static int read_build_id(const char *filename, struct build_id *bid) 543 { 544 size_t size = sizeof(bid->data); 545 int err = -1; 546 bfd *abfd; 547 548 abfd = bfd_openr(filename, NULL); 549 if (!abfd) 550 return -1; 551 552 if (!bfd_check_format(abfd, bfd_object)) { 553 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 554 goto out_close; 555 } 556 557 if (!abfd->build_id || abfd->build_id->size > size) 558 goto out_close; 559 560 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size); 561 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size); 562 err = bid->size = abfd->build_id->size; 563 564 out_close: 565 bfd_close(abfd); 566 return err; 567 } 568 569 #else // HAVE_LIBBFD_BUILDID_SUPPORT 570 571 static int read_build_id(const char *filename, struct build_id *bid) 572 { 573 size_t size = sizeof(bid->data); 574 int fd, err = -1; 575 Elf *elf; 576 577 if (size < BUILD_ID_SIZE) 578 goto out; 579 580 fd = open(filename, O_RDONLY); 581 if (fd < 0) 582 goto out; 583 584 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 585 if (elf == NULL) { 586 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 587 goto out_close; 588 } 589 590 err = elf_read_build_id(elf, bid->data, size); 591 if (err > 0) 592 bid->size = err; 593 594 elf_end(elf); 595 out_close: 596 close(fd); 597 out: 598 return err; 599 } 600 601 #endif // HAVE_LIBBFD_BUILDID_SUPPORT 602 603 int filename__read_build_id(const char *filename, struct build_id *bid) 604 { 605 struct kmod_path m = { .name = NULL, }; 606 char path[PATH_MAX]; 607 int err; 608 609 if (!filename) 610 return -EFAULT; 611 612 err = kmod_path__parse(&m, filename); 613 if (err) 614 return -1; 615 616 if (m.comp) { 617 int error = 0, fd; 618 619 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error); 620 if (fd < 0) { 621 pr_debug("Failed to decompress (error %d) %s\n", 622 error, filename); 623 return -1; 624 } 625 close(fd); 626 filename = path; 627 } 628 629 err = read_build_id(filename, bid); 630 631 if (m.comp) 632 unlink(filename); 633 return err; 634 } 635 636 int sysfs__read_build_id(const char *filename, struct build_id *bid) 637 { 638 size_t size = sizeof(bid->data); 639 int fd, err = -1; 640 641 fd = open(filename, O_RDONLY); 642 if (fd < 0) 643 goto out; 644 645 while (1) { 646 char bf[BUFSIZ]; 647 GElf_Nhdr nhdr; 648 size_t namesz, descsz; 649 650 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) 651 break; 652 653 namesz = NOTE_ALIGN(nhdr.n_namesz); 654 descsz = NOTE_ALIGN(nhdr.n_descsz); 655 if (nhdr.n_type == NT_GNU_BUILD_ID && 656 nhdr.n_namesz == sizeof("GNU")) { 657 if (read(fd, bf, namesz) != (ssize_t)namesz) 658 break; 659 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { 660 size_t sz = min(descsz, size); 661 if (read(fd, bid->data, sz) == (ssize_t)sz) { 662 memset(bid->data + sz, 0, size - sz); 663 bid->size = sz; 664 err = 0; 665 break; 666 } 667 } else if (read(fd, bf, descsz) != (ssize_t)descsz) 668 break; 669 } else { 670 int n = namesz + descsz; 671 672 if (n > (int)sizeof(bf)) { 673 n = sizeof(bf); 674 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", 675 __func__, filename, nhdr.n_namesz, nhdr.n_descsz); 676 } 677 if (read(fd, bf, n) != n) 678 break; 679 } 680 } 681 close(fd); 682 out: 683 return err; 684 } 685 686 #ifdef HAVE_LIBBFD_SUPPORT 687 688 int filename__read_debuglink(const char *filename, char *debuglink, 689 size_t size) 690 { 691 int err = -1; 692 asection *section; 693 bfd *abfd; 694 695 abfd = bfd_openr(filename, NULL); 696 if (!abfd) 697 return -1; 698 699 if (!bfd_check_format(abfd, bfd_object)) { 700 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 701 goto out_close; 702 } 703 704 section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); 705 if (!section) 706 goto out_close; 707 708 if (section->size > size) 709 goto out_close; 710 711 if (!bfd_get_section_contents(abfd, section, debuglink, 0, 712 section->size)) 713 goto out_close; 714 715 err = 0; 716 717 out_close: 718 bfd_close(abfd); 719 return err; 720 } 721 722 #else 723 724 int filename__read_debuglink(const char *filename, char *debuglink, 725 size_t size) 726 { 727 int fd, err = -1; 728 Elf *elf; 729 GElf_Ehdr ehdr; 730 GElf_Shdr shdr; 731 Elf_Data *data; 732 Elf_Scn *sec; 733 Elf_Kind ek; 734 735 fd = open(filename, O_RDONLY); 736 if (fd < 0) 737 goto out; 738 739 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 740 if (elf == NULL) { 741 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 742 goto out_close; 743 } 744 745 ek = elf_kind(elf); 746 if (ek != ELF_K_ELF) 747 goto out_elf_end; 748 749 if (gelf_getehdr(elf, &ehdr) == NULL) { 750 pr_err("%s: cannot get elf header.\n", __func__); 751 goto out_elf_end; 752 } 753 754 sec = elf_section_by_name(elf, &ehdr, &shdr, 755 ".gnu_debuglink", NULL); 756 if (sec == NULL) 757 goto out_elf_end; 758 759 data = elf_getdata(sec, NULL); 760 if (data == NULL) 761 goto out_elf_end; 762 763 /* the start of this section is a zero-terminated string */ 764 strncpy(debuglink, data->d_buf, size); 765 766 err = 0; 767 768 out_elf_end: 769 elf_end(elf); 770 out_close: 771 close(fd); 772 out: 773 return err; 774 } 775 776 #endif 777 778 static int dso__swap_init(struct dso *dso, unsigned char eidata) 779 { 780 static unsigned int const endian = 1; 781 782 dso->needs_swap = DSO_SWAP__NO; 783 784 switch (eidata) { 785 case ELFDATA2LSB: 786 /* We are big endian, DSO is little endian. */ 787 if (*(unsigned char const *)&endian != 1) 788 dso->needs_swap = DSO_SWAP__YES; 789 break; 790 791 case ELFDATA2MSB: 792 /* We are little endian, DSO is big endian. */ 793 if (*(unsigned char const *)&endian != 0) 794 dso->needs_swap = DSO_SWAP__YES; 795 break; 796 797 default: 798 pr_err("unrecognized DSO data encoding %d\n", eidata); 799 return -EINVAL; 800 } 801 802 return 0; 803 } 804 805 bool symsrc__possibly_runtime(struct symsrc *ss) 806 { 807 return ss->dynsym || ss->opdsec; 808 } 809 810 bool symsrc__has_symtab(struct symsrc *ss) 811 { 812 return ss->symtab != NULL; 813 } 814 815 void symsrc__destroy(struct symsrc *ss) 816 { 817 zfree(&ss->name); 818 elf_end(ss->elf); 819 close(ss->fd); 820 } 821 822 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) 823 { 824 /* 825 * Usually vmlinux is an ELF file with type ET_EXEC for most 826 * architectures; except Arm64 kernel is linked with option 827 * '-share', so need to check type ET_DYN. 828 */ 829 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL || 830 ehdr.e_type == ET_DYN; 831 } 832 833 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 834 enum dso_binary_type type) 835 { 836 GElf_Ehdr ehdr; 837 Elf *elf; 838 int fd; 839 840 if (dso__needs_decompress(dso)) { 841 fd = dso__decompress_kmodule_fd(dso, name); 842 if (fd < 0) 843 return -1; 844 845 type = dso->symtab_type; 846 } else { 847 fd = open(name, O_RDONLY); 848 if (fd < 0) { 849 dso->load_errno = errno; 850 return -1; 851 } 852 } 853 854 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 855 if (elf == NULL) { 856 pr_debug("%s: cannot read %s ELF file.\n", __func__, name); 857 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 858 goto out_close; 859 } 860 861 if (gelf_getehdr(elf, &ehdr) == NULL) { 862 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 863 pr_debug("%s: cannot get elf header.\n", __func__); 864 goto out_elf_end; 865 } 866 867 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { 868 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR; 869 goto out_elf_end; 870 } 871 872 /* Always reject images with a mismatched build-id: */ 873 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) { 874 u8 build_id[BUILD_ID_SIZE]; 875 struct build_id bid; 876 int size; 877 878 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE); 879 if (size <= 0) { 880 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; 881 goto out_elf_end; 882 } 883 884 build_id__init(&bid, build_id, size); 885 if (!dso__build_id_equal(dso, &bid)) { 886 pr_debug("%s: build id mismatch for %s.\n", __func__, name); 887 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; 888 goto out_elf_end; 889 } 890 } 891 892 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 893 894 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", 895 NULL); 896 if (ss->symshdr.sh_type != SHT_SYMTAB) 897 ss->symtab = NULL; 898 899 ss->dynsym_idx = 0; 900 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", 901 &ss->dynsym_idx); 902 if (ss->dynshdr.sh_type != SHT_DYNSYM) 903 ss->dynsym = NULL; 904 905 ss->opdidx = 0; 906 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", 907 &ss->opdidx); 908 if (ss->opdshdr.sh_type != SHT_PROGBITS) 909 ss->opdsec = NULL; 910 911 if (dso->kernel == DSO_SPACE__USER) 912 ss->adjust_symbols = true; 913 else 914 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); 915 916 ss->name = strdup(name); 917 if (!ss->name) { 918 dso->load_errno = errno; 919 goto out_elf_end; 920 } 921 922 ss->elf = elf; 923 ss->fd = fd; 924 ss->ehdr = ehdr; 925 ss->type = type; 926 927 return 0; 928 929 out_elf_end: 930 elf_end(elf); 931 out_close: 932 close(fd); 933 return -1; 934 } 935 936 /** 937 * ref_reloc_sym_not_found - has kernel relocation symbol been found. 938 * @kmap: kernel maps and relocation reference symbol 939 * 940 * This function returns %true if we are dealing with the kernel maps and the 941 * relocation reference symbol has not yet been found. Otherwise %false is 942 * returned. 943 */ 944 static bool ref_reloc_sym_not_found(struct kmap *kmap) 945 { 946 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && 947 !kmap->ref_reloc_sym->unrelocated_addr; 948 } 949 950 /** 951 * ref_reloc - kernel relocation offset. 952 * @kmap: kernel maps and relocation reference symbol 953 * 954 * This function returns the offset of kernel addresses as determined by using 955 * the relocation reference symbol i.e. if the kernel has not been relocated 956 * then the return value is zero. 957 */ 958 static u64 ref_reloc(struct kmap *kmap) 959 { 960 if (kmap && kmap->ref_reloc_sym && 961 kmap->ref_reloc_sym->unrelocated_addr) 962 return kmap->ref_reloc_sym->addr - 963 kmap->ref_reloc_sym->unrelocated_addr; 964 return 0; 965 } 966 967 void __weak arch__sym_update(struct symbol *s __maybe_unused, 968 GElf_Sym *sym __maybe_unused) { } 969 970 static int dso__process_kernel_symbol(struct dso *dso, struct map *map, 971 GElf_Sym *sym, GElf_Shdr *shdr, 972 struct maps *kmaps, struct kmap *kmap, 973 struct dso **curr_dsop, struct map **curr_mapp, 974 const char *section_name, 975 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) 976 { 977 struct dso *curr_dso = *curr_dsop; 978 struct map *curr_map; 979 char dso_name[PATH_MAX]; 980 981 /* Adjust symbol to map to file offset */ 982 if (adjust_kernel_syms) 983 sym->st_value -= shdr->sh_addr - shdr->sh_offset; 984 985 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0) 986 return 0; 987 988 if (strcmp(section_name, ".text") == 0) { 989 /* 990 * The initial kernel mapping is based on 991 * kallsyms and identity maps. Overwrite it to 992 * map to the kernel dso. 993 */ 994 if (*remap_kernel && dso->kernel && !kmodule) { 995 *remap_kernel = false; 996 map->start = shdr->sh_addr + ref_reloc(kmap); 997 map->end = map->start + shdr->sh_size; 998 map->pgoff = shdr->sh_offset; 999 map->map_ip = map__map_ip; 1000 map->unmap_ip = map__unmap_ip; 1001 /* Ensure maps are correctly ordered */ 1002 if (kmaps) { 1003 map__get(map); 1004 maps__remove(kmaps, map); 1005 maps__insert(kmaps, map); 1006 map__put(map); 1007 } 1008 } 1009 1010 /* 1011 * The initial module mapping is based on 1012 * /proc/modules mapped to offset zero. 1013 * Overwrite it to map to the module dso. 1014 */ 1015 if (*remap_kernel && kmodule) { 1016 *remap_kernel = false; 1017 map->pgoff = shdr->sh_offset; 1018 } 1019 1020 *curr_mapp = map; 1021 *curr_dsop = dso; 1022 return 0; 1023 } 1024 1025 if (!kmap) 1026 return 0; 1027 1028 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); 1029 1030 curr_map = maps__find_by_name(kmaps, dso_name); 1031 if (curr_map == NULL) { 1032 u64 start = sym->st_value; 1033 1034 if (kmodule) 1035 start += map->start + shdr->sh_offset; 1036 1037 curr_dso = dso__new(dso_name); 1038 if (curr_dso == NULL) 1039 return -1; 1040 curr_dso->kernel = dso->kernel; 1041 curr_dso->long_name = dso->long_name; 1042 curr_dso->long_name_len = dso->long_name_len; 1043 curr_map = map__new2(start, curr_dso); 1044 dso__put(curr_dso); 1045 if (curr_map == NULL) 1046 return -1; 1047 1048 if (curr_dso->kernel) 1049 map__kmap(curr_map)->kmaps = kmaps; 1050 1051 if (adjust_kernel_syms) { 1052 curr_map->start = shdr->sh_addr + ref_reloc(kmap); 1053 curr_map->end = curr_map->start + shdr->sh_size; 1054 curr_map->pgoff = shdr->sh_offset; 1055 } else { 1056 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; 1057 } 1058 curr_dso->symtab_type = dso->symtab_type; 1059 maps__insert(kmaps, curr_map); 1060 /* 1061 * Add it before we drop the referece to curr_map, i.e. while 1062 * we still are sure to have a reference to this DSO via 1063 * *curr_map->dso. 1064 */ 1065 dsos__add(&kmaps->machine->dsos, curr_dso); 1066 /* kmaps already got it */ 1067 map__put(curr_map); 1068 dso__set_loaded(curr_dso); 1069 *curr_mapp = curr_map; 1070 *curr_dsop = curr_dso; 1071 } else 1072 *curr_dsop = curr_map->dso; 1073 1074 return 0; 1075 } 1076 1077 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1078 struct symsrc *runtime_ss, int kmodule) 1079 { 1080 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; 1081 struct maps *kmaps = kmap ? map__kmaps(map) : NULL; 1082 struct map *curr_map = map; 1083 struct dso *curr_dso = dso; 1084 Elf_Data *symstrs, *secstrs; 1085 uint32_t nr_syms; 1086 int err = -1; 1087 uint32_t idx; 1088 GElf_Ehdr ehdr; 1089 GElf_Shdr shdr; 1090 GElf_Shdr tshdr; 1091 Elf_Data *syms, *opddata = NULL; 1092 GElf_Sym sym; 1093 Elf_Scn *sec, *sec_strndx; 1094 Elf *elf; 1095 int nr = 0; 1096 bool remap_kernel = false, adjust_kernel_syms = false; 1097 1098 if (kmap && !kmaps) 1099 return -1; 1100 1101 dso->symtab_type = syms_ss->type; 1102 dso->is_64_bit = syms_ss->is_64_bit; 1103 dso->rel = syms_ss->ehdr.e_type == ET_REL; 1104 1105 /* 1106 * Modules may already have symbols from kallsyms, but those symbols 1107 * have the wrong values for the dso maps, so remove them. 1108 */ 1109 if (kmodule && syms_ss->symtab) 1110 symbols__delete(&dso->symbols); 1111 1112 if (!syms_ss->symtab) { 1113 /* 1114 * If the vmlinux is stripped, fail so we will fall back 1115 * to using kallsyms. The vmlinux runtime symbols aren't 1116 * of much use. 1117 */ 1118 if (dso->kernel) 1119 goto out_elf_end; 1120 1121 syms_ss->symtab = syms_ss->dynsym; 1122 syms_ss->symshdr = syms_ss->dynshdr; 1123 } 1124 1125 elf = syms_ss->elf; 1126 ehdr = syms_ss->ehdr; 1127 sec = syms_ss->symtab; 1128 shdr = syms_ss->symshdr; 1129 1130 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, 1131 ".text", NULL)) 1132 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; 1133 1134 if (runtime_ss->opdsec) 1135 opddata = elf_rawdata(runtime_ss->opdsec, NULL); 1136 1137 syms = elf_getdata(sec, NULL); 1138 if (syms == NULL) 1139 goto out_elf_end; 1140 1141 sec = elf_getscn(elf, shdr.sh_link); 1142 if (sec == NULL) 1143 goto out_elf_end; 1144 1145 symstrs = elf_getdata(sec, NULL); 1146 if (symstrs == NULL) 1147 goto out_elf_end; 1148 1149 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); 1150 if (sec_strndx == NULL) 1151 goto out_elf_end; 1152 1153 secstrs = elf_getdata(sec_strndx, NULL); 1154 if (secstrs == NULL) 1155 goto out_elf_end; 1156 1157 nr_syms = shdr.sh_size / shdr.sh_entsize; 1158 1159 memset(&sym, 0, sizeof(sym)); 1160 1161 /* 1162 * The kernel relocation symbol is needed in advance in order to adjust 1163 * kernel maps correctly. 1164 */ 1165 if (ref_reloc_sym_not_found(kmap)) { 1166 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1167 const char *elf_name = elf_sym__name(&sym, symstrs); 1168 1169 if (strcmp(elf_name, kmap->ref_reloc_sym->name)) 1170 continue; 1171 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; 1172 map->reloc = kmap->ref_reloc_sym->addr - 1173 kmap->ref_reloc_sym->unrelocated_addr; 1174 break; 1175 } 1176 } 1177 1178 /* 1179 * Handle any relocation of vdso necessary because older kernels 1180 * attempted to prelink vdso to its virtual address. 1181 */ 1182 if (dso__is_vdso(dso)) 1183 map->reloc = map->start - dso->text_offset; 1184 1185 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); 1186 /* 1187 * Initial kernel and module mappings do not map to the dso. 1188 * Flag the fixups. 1189 */ 1190 if (dso->kernel) { 1191 remap_kernel = true; 1192 adjust_kernel_syms = dso->adjust_symbols; 1193 } 1194 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1195 struct symbol *f; 1196 const char *elf_name = elf_sym__name(&sym, symstrs); 1197 char *demangled = NULL; 1198 int is_label = elf_sym__is_label(&sym); 1199 const char *section_name; 1200 bool used_opd = false; 1201 1202 if (!is_label && !elf_sym__filter(&sym)) 1203 continue; 1204 1205 /* Reject ARM ELF "mapping symbols": these aren't unique and 1206 * don't identify functions, so will confuse the profile 1207 * output: */ 1208 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { 1209 if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) 1210 && (elf_name[2] == '\0' || elf_name[2] == '.')) 1211 continue; 1212 } 1213 1214 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { 1215 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; 1216 u64 *opd = opddata->d_buf + offset; 1217 sym.st_value = DSO__SWAP(dso, u64, *opd); 1218 sym.st_shndx = elf_addr_to_index(runtime_ss->elf, 1219 sym.st_value); 1220 used_opd = true; 1221 } 1222 /* 1223 * When loading symbols in a data mapping, ABS symbols (which 1224 * has a value of SHN_ABS in its st_shndx) failed at 1225 * elf_getscn(). And it marks the loading as a failure so 1226 * already loaded symbols cannot be fixed up. 1227 * 1228 * I'm not sure what should be done. Just ignore them for now. 1229 * - Namhyung Kim 1230 */ 1231 if (sym.st_shndx == SHN_ABS) 1232 continue; 1233 1234 sec = elf_getscn(syms_ss->elf, sym.st_shndx); 1235 if (!sec) 1236 goto out_elf_end; 1237 1238 gelf_getshdr(sec, &shdr); 1239 1240 /* 1241 * We have to fallback to runtime when syms' section header has 1242 * NOBITS set. NOBITS results in file offset (sh_offset) not 1243 * being incremented. So sh_offset used below has different 1244 * values for syms (invalid) and runtime (valid). 1245 */ 1246 if (shdr.sh_type == SHT_NOBITS) { 1247 sec = elf_getscn(runtime_ss->elf, sym.st_shndx); 1248 if (!sec) 1249 goto out_elf_end; 1250 1251 gelf_getshdr(sec, &shdr); 1252 } 1253 1254 if (is_label && !elf_sec__filter(&shdr, secstrs)) 1255 continue; 1256 1257 section_name = elf_sec__name(&shdr, secstrs); 1258 1259 /* On ARM, symbols for thumb functions have 1 added to 1260 * the symbol address as a flag - remove it */ 1261 if ((ehdr.e_machine == EM_ARM) && 1262 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && 1263 (sym.st_value & 1)) 1264 --sym.st_value; 1265 1266 if (dso->kernel) { 1267 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, 1268 section_name, adjust_kernel_syms, kmodule, &remap_kernel)) 1269 goto out_elf_end; 1270 } else if ((used_opd && runtime_ss->adjust_symbols) || 1271 (!used_opd && syms_ss->adjust_symbols)) { 1272 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1273 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__, 1274 (u64)sym.st_value, (u64)shdr.sh_addr, 1275 (u64)shdr.sh_offset); 1276 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 1277 } 1278 1279 demangled = demangle_sym(dso, kmodule, elf_name); 1280 if (demangled != NULL) 1281 elf_name = demangled; 1282 1283 f = symbol__new(sym.st_value, sym.st_size, 1284 GELF_ST_BIND(sym.st_info), 1285 GELF_ST_TYPE(sym.st_info), elf_name); 1286 free(demangled); 1287 if (!f) 1288 goto out_elf_end; 1289 1290 arch__sym_update(f, &sym); 1291 1292 __symbols__insert(&curr_dso->symbols, f, dso->kernel); 1293 nr++; 1294 } 1295 1296 /* 1297 * For misannotated, zeroed, ASM function sizes. 1298 */ 1299 if (nr > 0) { 1300 symbols__fixup_end(&dso->symbols); 1301 symbols__fixup_duplicate(&dso->symbols); 1302 if (kmap) { 1303 /* 1304 * We need to fixup this here too because we create new 1305 * maps here, for things like vsyscall sections. 1306 */ 1307 maps__fixup_end(kmaps); 1308 } 1309 } 1310 err = nr; 1311 out_elf_end: 1312 return err; 1313 } 1314 1315 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) 1316 { 1317 GElf_Phdr phdr; 1318 size_t i, phdrnum; 1319 int err; 1320 u64 sz; 1321 1322 if (elf_getphdrnum(elf, &phdrnum)) 1323 return -1; 1324 1325 for (i = 0; i < phdrnum; i++) { 1326 if (gelf_getphdr(elf, i, &phdr) == NULL) 1327 return -1; 1328 if (phdr.p_type != PT_LOAD) 1329 continue; 1330 if (exe) { 1331 if (!(phdr.p_flags & PF_X)) 1332 continue; 1333 } else { 1334 if (!(phdr.p_flags & PF_R)) 1335 continue; 1336 } 1337 sz = min(phdr.p_memsz, phdr.p_filesz); 1338 if (!sz) 1339 continue; 1340 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); 1341 if (err) 1342 return err; 1343 } 1344 return 0; 1345 } 1346 1347 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, 1348 bool *is_64_bit) 1349 { 1350 int err; 1351 Elf *elf; 1352 1353 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1354 if (elf == NULL) 1355 return -1; 1356 1357 if (is_64_bit) 1358 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1359 1360 err = elf_read_maps(elf, exe, mapfn, data); 1361 1362 elf_end(elf); 1363 return err; 1364 } 1365 1366 enum dso_type dso__type_fd(int fd) 1367 { 1368 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 1369 GElf_Ehdr ehdr; 1370 Elf_Kind ek; 1371 Elf *elf; 1372 1373 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1374 if (elf == NULL) 1375 goto out; 1376 1377 ek = elf_kind(elf); 1378 if (ek != ELF_K_ELF) 1379 goto out_end; 1380 1381 if (gelf_getclass(elf) == ELFCLASS64) { 1382 dso_type = DSO__TYPE_64BIT; 1383 goto out_end; 1384 } 1385 1386 if (gelf_getehdr(elf, &ehdr) == NULL) 1387 goto out_end; 1388 1389 if (ehdr.e_machine == EM_X86_64) 1390 dso_type = DSO__TYPE_X32BIT; 1391 else 1392 dso_type = DSO__TYPE_32BIT; 1393 out_end: 1394 elf_end(elf); 1395 out: 1396 return dso_type; 1397 } 1398 1399 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) 1400 { 1401 ssize_t r; 1402 size_t n; 1403 int err = -1; 1404 char *buf = malloc(page_size); 1405 1406 if (buf == NULL) 1407 return -1; 1408 1409 if (lseek(to, to_offs, SEEK_SET) != to_offs) 1410 goto out; 1411 1412 if (lseek(from, from_offs, SEEK_SET) != from_offs) 1413 goto out; 1414 1415 while (len) { 1416 n = page_size; 1417 if (len < n) 1418 n = len; 1419 /* Use read because mmap won't work on proc files */ 1420 r = read(from, buf, n); 1421 if (r < 0) 1422 goto out; 1423 if (!r) 1424 break; 1425 n = r; 1426 r = write(to, buf, n); 1427 if (r < 0) 1428 goto out; 1429 if ((size_t)r != n) 1430 goto out; 1431 len -= n; 1432 } 1433 1434 err = 0; 1435 out: 1436 free(buf); 1437 return err; 1438 } 1439 1440 struct kcore { 1441 int fd; 1442 int elfclass; 1443 Elf *elf; 1444 GElf_Ehdr ehdr; 1445 }; 1446 1447 static int kcore__open(struct kcore *kcore, const char *filename) 1448 { 1449 GElf_Ehdr *ehdr; 1450 1451 kcore->fd = open(filename, O_RDONLY); 1452 if (kcore->fd == -1) 1453 return -1; 1454 1455 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); 1456 if (!kcore->elf) 1457 goto out_close; 1458 1459 kcore->elfclass = gelf_getclass(kcore->elf); 1460 if (kcore->elfclass == ELFCLASSNONE) 1461 goto out_end; 1462 1463 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); 1464 if (!ehdr) 1465 goto out_end; 1466 1467 return 0; 1468 1469 out_end: 1470 elf_end(kcore->elf); 1471 out_close: 1472 close(kcore->fd); 1473 return -1; 1474 } 1475 1476 static int kcore__init(struct kcore *kcore, char *filename, int elfclass, 1477 bool temp) 1478 { 1479 kcore->elfclass = elfclass; 1480 1481 if (temp) 1482 kcore->fd = mkstemp(filename); 1483 else 1484 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); 1485 if (kcore->fd == -1) 1486 return -1; 1487 1488 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); 1489 if (!kcore->elf) 1490 goto out_close; 1491 1492 if (!gelf_newehdr(kcore->elf, elfclass)) 1493 goto out_end; 1494 1495 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); 1496 1497 return 0; 1498 1499 out_end: 1500 elf_end(kcore->elf); 1501 out_close: 1502 close(kcore->fd); 1503 unlink(filename); 1504 return -1; 1505 } 1506 1507 static void kcore__close(struct kcore *kcore) 1508 { 1509 elf_end(kcore->elf); 1510 close(kcore->fd); 1511 } 1512 1513 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) 1514 { 1515 GElf_Ehdr *ehdr = &to->ehdr; 1516 GElf_Ehdr *kehdr = &from->ehdr; 1517 1518 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); 1519 ehdr->e_type = kehdr->e_type; 1520 ehdr->e_machine = kehdr->e_machine; 1521 ehdr->e_version = kehdr->e_version; 1522 ehdr->e_entry = 0; 1523 ehdr->e_shoff = 0; 1524 ehdr->e_flags = kehdr->e_flags; 1525 ehdr->e_phnum = count; 1526 ehdr->e_shentsize = 0; 1527 ehdr->e_shnum = 0; 1528 ehdr->e_shstrndx = 0; 1529 1530 if (from->elfclass == ELFCLASS32) { 1531 ehdr->e_phoff = sizeof(Elf32_Ehdr); 1532 ehdr->e_ehsize = sizeof(Elf32_Ehdr); 1533 ehdr->e_phentsize = sizeof(Elf32_Phdr); 1534 } else { 1535 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1536 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1537 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1538 } 1539 1540 if (!gelf_update_ehdr(to->elf, ehdr)) 1541 return -1; 1542 1543 if (!gelf_newphdr(to->elf, count)) 1544 return -1; 1545 1546 return 0; 1547 } 1548 1549 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, 1550 u64 addr, u64 len) 1551 { 1552 GElf_Phdr phdr = { 1553 .p_type = PT_LOAD, 1554 .p_flags = PF_R | PF_W | PF_X, 1555 .p_offset = offset, 1556 .p_vaddr = addr, 1557 .p_paddr = 0, 1558 .p_filesz = len, 1559 .p_memsz = len, 1560 .p_align = page_size, 1561 }; 1562 1563 if (!gelf_update_phdr(kcore->elf, idx, &phdr)) 1564 return -1; 1565 1566 return 0; 1567 } 1568 1569 static off_t kcore__write(struct kcore *kcore) 1570 { 1571 return elf_update(kcore->elf, ELF_C_WRITE); 1572 } 1573 1574 struct phdr_data { 1575 off_t offset; 1576 off_t rel; 1577 u64 addr; 1578 u64 len; 1579 struct list_head node; 1580 struct phdr_data *remaps; 1581 }; 1582 1583 struct sym_data { 1584 u64 addr; 1585 struct list_head node; 1586 }; 1587 1588 struct kcore_copy_info { 1589 u64 stext; 1590 u64 etext; 1591 u64 first_symbol; 1592 u64 last_symbol; 1593 u64 first_module; 1594 u64 first_module_symbol; 1595 u64 last_module_symbol; 1596 size_t phnum; 1597 struct list_head phdrs; 1598 struct list_head syms; 1599 }; 1600 1601 #define kcore_copy__for_each_phdr(k, p) \ 1602 list_for_each_entry((p), &(k)->phdrs, node) 1603 1604 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset) 1605 { 1606 struct phdr_data *p = zalloc(sizeof(*p)); 1607 1608 if (p) { 1609 p->addr = addr; 1610 p->len = len; 1611 p->offset = offset; 1612 } 1613 1614 return p; 1615 } 1616 1617 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci, 1618 u64 addr, u64 len, 1619 off_t offset) 1620 { 1621 struct phdr_data *p = phdr_data__new(addr, len, offset); 1622 1623 if (p) 1624 list_add_tail(&p->node, &kci->phdrs); 1625 1626 return p; 1627 } 1628 1629 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci) 1630 { 1631 struct phdr_data *p, *tmp; 1632 1633 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) { 1634 list_del_init(&p->node); 1635 free(p); 1636 } 1637 } 1638 1639 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci, 1640 u64 addr) 1641 { 1642 struct sym_data *s = zalloc(sizeof(*s)); 1643 1644 if (s) { 1645 s->addr = addr; 1646 list_add_tail(&s->node, &kci->syms); 1647 } 1648 1649 return s; 1650 } 1651 1652 static void kcore_copy__free_syms(struct kcore_copy_info *kci) 1653 { 1654 struct sym_data *s, *tmp; 1655 1656 list_for_each_entry_safe(s, tmp, &kci->syms, node) { 1657 list_del_init(&s->node); 1658 free(s); 1659 } 1660 } 1661 1662 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 1663 u64 start) 1664 { 1665 struct kcore_copy_info *kci = arg; 1666 1667 if (!kallsyms__is_function(type)) 1668 return 0; 1669 1670 if (strchr(name, '[')) { 1671 if (!kci->first_module_symbol || start < kci->first_module_symbol) 1672 kci->first_module_symbol = start; 1673 if (start > kci->last_module_symbol) 1674 kci->last_module_symbol = start; 1675 return 0; 1676 } 1677 1678 if (!kci->first_symbol || start < kci->first_symbol) 1679 kci->first_symbol = start; 1680 1681 if (!kci->last_symbol || start > kci->last_symbol) 1682 kci->last_symbol = start; 1683 1684 if (!strcmp(name, "_stext")) { 1685 kci->stext = start; 1686 return 0; 1687 } 1688 1689 if (!strcmp(name, "_etext")) { 1690 kci->etext = start; 1691 return 0; 1692 } 1693 1694 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start)) 1695 return -1; 1696 1697 return 0; 1698 } 1699 1700 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, 1701 const char *dir) 1702 { 1703 char kallsyms_filename[PATH_MAX]; 1704 1705 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); 1706 1707 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) 1708 return -1; 1709 1710 if (kallsyms__parse(kallsyms_filename, kci, 1711 kcore_copy__process_kallsyms) < 0) 1712 return -1; 1713 1714 return 0; 1715 } 1716 1717 static int kcore_copy__process_modules(void *arg, 1718 const char *name __maybe_unused, 1719 u64 start, u64 size __maybe_unused) 1720 { 1721 struct kcore_copy_info *kci = arg; 1722 1723 if (!kci->first_module || start < kci->first_module) 1724 kci->first_module = start; 1725 1726 return 0; 1727 } 1728 1729 static int kcore_copy__parse_modules(struct kcore_copy_info *kci, 1730 const char *dir) 1731 { 1732 char modules_filename[PATH_MAX]; 1733 1734 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); 1735 1736 if (symbol__restricted_filename(modules_filename, "/proc/modules")) 1737 return -1; 1738 1739 if (modules__parse(modules_filename, kci, 1740 kcore_copy__process_modules) < 0) 1741 return -1; 1742 1743 return 0; 1744 } 1745 1746 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end, 1747 u64 pgoff, u64 s, u64 e) 1748 { 1749 u64 len, offset; 1750 1751 if (s < start || s >= end) 1752 return 0; 1753 1754 offset = (s - start) + pgoff; 1755 len = e < end ? e - s : end - s; 1756 1757 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1; 1758 } 1759 1760 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) 1761 { 1762 struct kcore_copy_info *kci = data; 1763 u64 end = start + len; 1764 struct sym_data *sdat; 1765 1766 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext)) 1767 return -1; 1768 1769 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module, 1770 kci->last_module_symbol)) 1771 return -1; 1772 1773 list_for_each_entry(sdat, &kci->syms, node) { 1774 u64 s = round_down(sdat->addr, page_size); 1775 1776 if (kcore_copy__map(kci, start, end, pgoff, s, s + len)) 1777 return -1; 1778 } 1779 1780 return 0; 1781 } 1782 1783 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) 1784 { 1785 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) 1786 return -1; 1787 1788 return 0; 1789 } 1790 1791 static void kcore_copy__find_remaps(struct kcore_copy_info *kci) 1792 { 1793 struct phdr_data *p, *k = NULL; 1794 u64 kend; 1795 1796 if (!kci->stext) 1797 return; 1798 1799 /* Find phdr that corresponds to the kernel map (contains stext) */ 1800 kcore_copy__for_each_phdr(kci, p) { 1801 u64 pend = p->addr + p->len - 1; 1802 1803 if (p->addr <= kci->stext && pend >= kci->stext) { 1804 k = p; 1805 break; 1806 } 1807 } 1808 1809 if (!k) 1810 return; 1811 1812 kend = k->offset + k->len; 1813 1814 /* Find phdrs that remap the kernel */ 1815 kcore_copy__for_each_phdr(kci, p) { 1816 u64 pend = p->offset + p->len; 1817 1818 if (p == k) 1819 continue; 1820 1821 if (p->offset >= k->offset && pend <= kend) 1822 p->remaps = k; 1823 } 1824 } 1825 1826 static void kcore_copy__layout(struct kcore_copy_info *kci) 1827 { 1828 struct phdr_data *p; 1829 off_t rel = 0; 1830 1831 kcore_copy__find_remaps(kci); 1832 1833 kcore_copy__for_each_phdr(kci, p) { 1834 if (!p->remaps) { 1835 p->rel = rel; 1836 rel += p->len; 1837 } 1838 kci->phnum += 1; 1839 } 1840 1841 kcore_copy__for_each_phdr(kci, p) { 1842 struct phdr_data *k = p->remaps; 1843 1844 if (k) 1845 p->rel = p->offset - k->offset + k->rel; 1846 } 1847 } 1848 1849 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 1850 Elf *elf) 1851 { 1852 if (kcore_copy__parse_kallsyms(kci, dir)) 1853 return -1; 1854 1855 if (kcore_copy__parse_modules(kci, dir)) 1856 return -1; 1857 1858 if (kci->stext) 1859 kci->stext = round_down(kci->stext, page_size); 1860 else 1861 kci->stext = round_down(kci->first_symbol, page_size); 1862 1863 if (kci->etext) { 1864 kci->etext = round_up(kci->etext, page_size); 1865 } else if (kci->last_symbol) { 1866 kci->etext = round_up(kci->last_symbol, page_size); 1867 kci->etext += page_size; 1868 } 1869 1870 if (kci->first_module_symbol && 1871 (!kci->first_module || kci->first_module_symbol < kci->first_module)) 1872 kci->first_module = kci->first_module_symbol; 1873 1874 kci->first_module = round_down(kci->first_module, page_size); 1875 1876 if (kci->last_module_symbol) { 1877 kci->last_module_symbol = round_up(kci->last_module_symbol, 1878 page_size); 1879 kci->last_module_symbol += page_size; 1880 } 1881 1882 if (!kci->stext || !kci->etext) 1883 return -1; 1884 1885 if (kci->first_module && !kci->last_module_symbol) 1886 return -1; 1887 1888 if (kcore_copy__read_maps(kci, elf)) 1889 return -1; 1890 1891 kcore_copy__layout(kci); 1892 1893 return 0; 1894 } 1895 1896 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, 1897 const char *name) 1898 { 1899 char from_filename[PATH_MAX]; 1900 char to_filename[PATH_MAX]; 1901 1902 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1903 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1904 1905 return copyfile_mode(from_filename, to_filename, 0400); 1906 } 1907 1908 static int kcore_copy__unlink(const char *dir, const char *name) 1909 { 1910 char filename[PATH_MAX]; 1911 1912 scnprintf(filename, PATH_MAX, "%s/%s", dir, name); 1913 1914 return unlink(filename); 1915 } 1916 1917 static int kcore_copy__compare_fds(int from, int to) 1918 { 1919 char *buf_from; 1920 char *buf_to; 1921 ssize_t ret; 1922 size_t len; 1923 int err = -1; 1924 1925 buf_from = malloc(page_size); 1926 buf_to = malloc(page_size); 1927 if (!buf_from || !buf_to) 1928 goto out; 1929 1930 while (1) { 1931 /* Use read because mmap won't work on proc files */ 1932 ret = read(from, buf_from, page_size); 1933 if (ret < 0) 1934 goto out; 1935 1936 if (!ret) 1937 break; 1938 1939 len = ret; 1940 1941 if (readn(to, buf_to, len) != (int)len) 1942 goto out; 1943 1944 if (memcmp(buf_from, buf_to, len)) 1945 goto out; 1946 } 1947 1948 err = 0; 1949 out: 1950 free(buf_to); 1951 free(buf_from); 1952 return err; 1953 } 1954 1955 static int kcore_copy__compare_files(const char *from_filename, 1956 const char *to_filename) 1957 { 1958 int from, to, err = -1; 1959 1960 from = open(from_filename, O_RDONLY); 1961 if (from < 0) 1962 return -1; 1963 1964 to = open(to_filename, O_RDONLY); 1965 if (to < 0) 1966 goto out_close_from; 1967 1968 err = kcore_copy__compare_fds(from, to); 1969 1970 close(to); 1971 out_close_from: 1972 close(from); 1973 return err; 1974 } 1975 1976 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, 1977 const char *name) 1978 { 1979 char from_filename[PATH_MAX]; 1980 char to_filename[PATH_MAX]; 1981 1982 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1983 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1984 1985 return kcore_copy__compare_files(from_filename, to_filename); 1986 } 1987 1988 /** 1989 * kcore_copy - copy kallsyms, modules and kcore from one directory to another. 1990 * @from_dir: from directory 1991 * @to_dir: to directory 1992 * 1993 * This function copies kallsyms, modules and kcore files from one directory to 1994 * another. kallsyms and modules are copied entirely. Only code segments are 1995 * copied from kcore. It is assumed that two segments suffice: one for the 1996 * kernel proper and one for all the modules. The code segments are determined 1997 * from kallsyms and modules files. The kernel map starts at _stext or the 1998 * lowest function symbol, and ends at _etext or the highest function symbol. 1999 * The module map starts at the lowest module address and ends at the highest 2000 * module symbol. Start addresses are rounded down to the nearest page. End 2001 * addresses are rounded up to the nearest page. An extra page is added to the 2002 * highest kernel symbol and highest module symbol to, hopefully, encompass that 2003 * symbol too. Because it contains only code sections, the resulting kcore is 2004 * unusual. One significant peculiarity is that the mapping (start -> pgoff) 2005 * is not the same for the kernel map and the modules map. That happens because 2006 * the data is copied adjacently whereas the original kcore has gaps. Finally, 2007 * kallsyms and modules files are compared with their copies to check that 2008 * modules have not been loaded or unloaded while the copies were taking place. 2009 * 2010 * Return: %0 on success, %-1 on failure. 2011 */ 2012 int kcore_copy(const char *from_dir, const char *to_dir) 2013 { 2014 struct kcore kcore; 2015 struct kcore extract; 2016 int idx = 0, err = -1; 2017 off_t offset, sz; 2018 struct kcore_copy_info kci = { .stext = 0, }; 2019 char kcore_filename[PATH_MAX]; 2020 char extract_filename[PATH_MAX]; 2021 struct phdr_data *p; 2022 2023 INIT_LIST_HEAD(&kci.phdrs); 2024 INIT_LIST_HEAD(&kci.syms); 2025 2026 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) 2027 return -1; 2028 2029 if (kcore_copy__copy_file(from_dir, to_dir, "modules")) 2030 goto out_unlink_kallsyms; 2031 2032 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); 2033 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); 2034 2035 if (kcore__open(&kcore, kcore_filename)) 2036 goto out_unlink_modules; 2037 2038 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) 2039 goto out_kcore_close; 2040 2041 if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) 2042 goto out_kcore_close; 2043 2044 if (kcore__copy_hdr(&kcore, &extract, kci.phnum)) 2045 goto out_extract_close; 2046 2047 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) + 2048 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT); 2049 offset = round_up(offset, page_size); 2050 2051 kcore_copy__for_each_phdr(&kci, p) { 2052 off_t offs = p->rel + offset; 2053 2054 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len)) 2055 goto out_extract_close; 2056 } 2057 2058 sz = kcore__write(&extract); 2059 if (sz < 0 || sz > offset) 2060 goto out_extract_close; 2061 2062 kcore_copy__for_each_phdr(&kci, p) { 2063 off_t offs = p->rel + offset; 2064 2065 if (p->remaps) 2066 continue; 2067 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len)) 2068 goto out_extract_close; 2069 } 2070 2071 if (kcore_copy__compare_file(from_dir, to_dir, "modules")) 2072 goto out_extract_close; 2073 2074 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) 2075 goto out_extract_close; 2076 2077 err = 0; 2078 2079 out_extract_close: 2080 kcore__close(&extract); 2081 if (err) 2082 unlink(extract_filename); 2083 out_kcore_close: 2084 kcore__close(&kcore); 2085 out_unlink_modules: 2086 if (err) 2087 kcore_copy__unlink(to_dir, "modules"); 2088 out_unlink_kallsyms: 2089 if (err) 2090 kcore_copy__unlink(to_dir, "kallsyms"); 2091 2092 kcore_copy__free_phdrs(&kci); 2093 kcore_copy__free_syms(&kci); 2094 2095 return err; 2096 } 2097 2098 int kcore_extract__create(struct kcore_extract *kce) 2099 { 2100 struct kcore kcore; 2101 struct kcore extract; 2102 size_t count = 1; 2103 int idx = 0, err = -1; 2104 off_t offset = page_size, sz; 2105 2106 if (kcore__open(&kcore, kce->kcore_filename)) 2107 return -1; 2108 2109 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); 2110 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) 2111 goto out_kcore_close; 2112 2113 if (kcore__copy_hdr(&kcore, &extract, count)) 2114 goto out_extract_close; 2115 2116 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) 2117 goto out_extract_close; 2118 2119 sz = kcore__write(&extract); 2120 if (sz < 0 || sz > offset) 2121 goto out_extract_close; 2122 2123 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) 2124 goto out_extract_close; 2125 2126 err = 0; 2127 2128 out_extract_close: 2129 kcore__close(&extract); 2130 if (err) 2131 unlink(kce->extract_filename); 2132 out_kcore_close: 2133 kcore__close(&kcore); 2134 2135 return err; 2136 } 2137 2138 void kcore_extract__delete(struct kcore_extract *kce) 2139 { 2140 unlink(kce->extract_filename); 2141 } 2142 2143 #ifdef HAVE_GELF_GETNOTE_SUPPORT 2144 2145 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off) 2146 { 2147 if (!base_off) 2148 return; 2149 2150 if (tmp->bit32) 2151 tmp->addr.a32[SDT_NOTE_IDX_LOC] = 2152 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off - 2153 tmp->addr.a32[SDT_NOTE_IDX_BASE]; 2154 else 2155 tmp->addr.a64[SDT_NOTE_IDX_LOC] = 2156 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off - 2157 tmp->addr.a64[SDT_NOTE_IDX_BASE]; 2158 } 2159 2160 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr, 2161 GElf_Addr base_off) 2162 { 2163 if (!base_off) 2164 return; 2165 2166 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR]) 2167 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2168 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR]) 2169 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2170 } 2171 2172 /** 2173 * populate_sdt_note : Parse raw data and identify SDT note 2174 * @elf: elf of the opened file 2175 * @data: raw data of a section with description offset applied 2176 * @len: note description size 2177 * @type: type of the note 2178 * @sdt_notes: List to add the SDT note 2179 * 2180 * Responsible for parsing the @data in section .note.stapsdt in @elf and 2181 * if its an SDT note, it appends to @sdt_notes list. 2182 */ 2183 static int populate_sdt_note(Elf **elf, const char *data, size_t len, 2184 struct list_head *sdt_notes) 2185 { 2186 const char *provider, *name, *args; 2187 struct sdt_note *tmp = NULL; 2188 GElf_Ehdr ehdr; 2189 GElf_Shdr shdr; 2190 int ret = -EINVAL; 2191 2192 union { 2193 Elf64_Addr a64[NR_ADDR]; 2194 Elf32_Addr a32[NR_ADDR]; 2195 } buf; 2196 2197 Elf_Data dst = { 2198 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, 2199 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), 2200 .d_off = 0, .d_align = 0 2201 }; 2202 Elf_Data src = { 2203 .d_buf = (void *) data, .d_type = ELF_T_ADDR, 2204 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, 2205 .d_align = 0 2206 }; 2207 2208 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); 2209 if (!tmp) { 2210 ret = -ENOMEM; 2211 goto out_err; 2212 } 2213 2214 INIT_LIST_HEAD(&tmp->note_list); 2215 2216 if (len < dst.d_size + 3) 2217 goto out_free_note; 2218 2219 /* Translation from file representation to memory representation */ 2220 if (gelf_xlatetom(*elf, &dst, &src, 2221 elf_getident(*elf, NULL)[EI_DATA]) == NULL) { 2222 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); 2223 goto out_free_note; 2224 } 2225 2226 /* Populate the fields of sdt_note */ 2227 provider = data + dst.d_size; 2228 2229 name = (const char *)memchr(provider, '\0', data + len - provider); 2230 if (name++ == NULL) 2231 goto out_free_note; 2232 2233 tmp->provider = strdup(provider); 2234 if (!tmp->provider) { 2235 ret = -ENOMEM; 2236 goto out_free_note; 2237 } 2238 tmp->name = strdup(name); 2239 if (!tmp->name) { 2240 ret = -ENOMEM; 2241 goto out_free_prov; 2242 } 2243 2244 args = memchr(name, '\0', data + len - name); 2245 2246 /* 2247 * There is no argument if: 2248 * - We reached the end of the note; 2249 * - There is not enough room to hold a potential string; 2250 * - The argument string is empty or just contains ':'. 2251 */ 2252 if (args == NULL || data + len - args < 2 || 2253 args[1] == ':' || args[1] == '\0') 2254 tmp->args = NULL; 2255 else { 2256 tmp->args = strdup(++args); 2257 if (!tmp->args) { 2258 ret = -ENOMEM; 2259 goto out_free_name; 2260 } 2261 } 2262 2263 if (gelf_getclass(*elf) == ELFCLASS32) { 2264 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); 2265 tmp->bit32 = true; 2266 } else { 2267 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); 2268 tmp->bit32 = false; 2269 } 2270 2271 if (!gelf_getehdr(*elf, &ehdr)) { 2272 pr_debug("%s : cannot get elf header.\n", __func__); 2273 ret = -EBADF; 2274 goto out_free_args; 2275 } 2276 2277 /* Adjust the prelink effect : 2278 * Find out the .stapsdt.base section. 2279 * This scn will help us to handle prelinking (if present). 2280 * Compare the retrieved file offset of the base section with the 2281 * base address in the description of the SDT note. If its different, 2282 * then accordingly, adjust the note location. 2283 */ 2284 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) 2285 sdt_adjust_loc(tmp, shdr.sh_offset); 2286 2287 /* Adjust reference counter offset */ 2288 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) 2289 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset); 2290 2291 list_add_tail(&tmp->note_list, sdt_notes); 2292 return 0; 2293 2294 out_free_args: 2295 zfree(&tmp->args); 2296 out_free_name: 2297 zfree(&tmp->name); 2298 out_free_prov: 2299 zfree(&tmp->provider); 2300 out_free_note: 2301 free(tmp); 2302 out_err: 2303 return ret; 2304 } 2305 2306 /** 2307 * construct_sdt_notes_list : constructs a list of SDT notes 2308 * @elf : elf to look into 2309 * @sdt_notes : empty list_head 2310 * 2311 * Scans the sections in 'elf' for the section 2312 * .note.stapsdt. It, then calls populate_sdt_note to find 2313 * out the SDT events and populates the 'sdt_notes'. 2314 */ 2315 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) 2316 { 2317 GElf_Ehdr ehdr; 2318 Elf_Scn *scn = NULL; 2319 Elf_Data *data; 2320 GElf_Shdr shdr; 2321 size_t shstrndx, next; 2322 GElf_Nhdr nhdr; 2323 size_t name_off, desc_off, offset; 2324 int ret = 0; 2325 2326 if (gelf_getehdr(elf, &ehdr) == NULL) { 2327 ret = -EBADF; 2328 goto out_ret; 2329 } 2330 if (elf_getshdrstrndx(elf, &shstrndx) != 0) { 2331 ret = -EBADF; 2332 goto out_ret; 2333 } 2334 2335 /* Look for the required section */ 2336 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); 2337 if (!scn) { 2338 ret = -ENOENT; 2339 goto out_ret; 2340 } 2341 2342 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { 2343 ret = -ENOENT; 2344 goto out_ret; 2345 } 2346 2347 data = elf_getdata(scn, NULL); 2348 2349 /* Get the SDT notes */ 2350 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, 2351 &desc_off)) > 0; offset = next) { 2352 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && 2353 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, 2354 sizeof(SDT_NOTE_NAME))) { 2355 /* Check the type of the note */ 2356 if (nhdr.n_type != SDT_NOTE_TYPE) 2357 goto out_ret; 2358 2359 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), 2360 nhdr.n_descsz, sdt_notes); 2361 if (ret < 0) 2362 goto out_ret; 2363 } 2364 } 2365 if (list_empty(sdt_notes)) 2366 ret = -ENOENT; 2367 2368 out_ret: 2369 return ret; 2370 } 2371 2372 /** 2373 * get_sdt_note_list : Wrapper to construct a list of sdt notes 2374 * @head : empty list_head 2375 * @target : file to find SDT notes from 2376 * 2377 * This opens the file, initializes 2378 * the ELF and then calls construct_sdt_notes_list. 2379 */ 2380 int get_sdt_note_list(struct list_head *head, const char *target) 2381 { 2382 Elf *elf; 2383 int fd, ret; 2384 2385 fd = open(target, O_RDONLY); 2386 if (fd < 0) 2387 return -EBADF; 2388 2389 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 2390 if (!elf) { 2391 ret = -EBADF; 2392 goto out_close; 2393 } 2394 ret = construct_sdt_notes_list(elf, head); 2395 elf_end(elf); 2396 out_close: 2397 close(fd); 2398 return ret; 2399 } 2400 2401 /** 2402 * cleanup_sdt_note_list : free the sdt notes' list 2403 * @sdt_notes: sdt notes' list 2404 * 2405 * Free up the SDT notes in @sdt_notes. 2406 * Returns the number of SDT notes free'd. 2407 */ 2408 int cleanup_sdt_note_list(struct list_head *sdt_notes) 2409 { 2410 struct sdt_note *tmp, *pos; 2411 int nr_free = 0; 2412 2413 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { 2414 list_del_init(&pos->note_list); 2415 zfree(&pos->name); 2416 zfree(&pos->provider); 2417 free(pos); 2418 nr_free++; 2419 } 2420 return nr_free; 2421 } 2422 2423 /** 2424 * sdt_notes__get_count: Counts the number of sdt events 2425 * @start: list_head to sdt_notes list 2426 * 2427 * Returns the number of SDT notes in a list 2428 */ 2429 int sdt_notes__get_count(struct list_head *start) 2430 { 2431 struct sdt_note *sdt_ptr; 2432 int count = 0; 2433 2434 list_for_each_entry(sdt_ptr, start, note_list) 2435 count++; 2436 return count; 2437 } 2438 #endif 2439 2440 void symbol__elf_init(void) 2441 { 2442 elf_version(EV_CURRENT); 2443 } 2444