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