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 bool symsrc__possibly_runtime(struct symsrc *ss) 641 { 642 return ss->dynsym || ss->opdsec; 643 } 644 645 bool symsrc__has_symtab(struct symsrc *ss) 646 { 647 return ss->symtab != NULL; 648 } 649 650 void symsrc__destroy(struct symsrc *ss) 651 { 652 zfree(&ss->name); 653 elf_end(ss->elf); 654 close(ss->fd); 655 } 656 657 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr) 658 { 659 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL; 660 } 661 662 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 663 enum dso_binary_type type) 664 { 665 int err = -1; 666 GElf_Ehdr ehdr; 667 Elf *elf; 668 int fd; 669 670 if (dso__needs_decompress(dso)) { 671 fd = dso__decompress_kmodule_fd(dso, name); 672 if (fd < 0) 673 return -1; 674 675 type = dso->symtab_type; 676 } else { 677 fd = open(name, O_RDONLY); 678 if (fd < 0) { 679 dso->load_errno = errno; 680 return -1; 681 } 682 } 683 684 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 685 if (elf == NULL) { 686 pr_debug("%s: cannot read %s ELF file.\n", __func__, name); 687 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 688 goto out_close; 689 } 690 691 if (gelf_getehdr(elf, &ehdr) == NULL) { 692 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 693 pr_debug("%s: cannot get elf header.\n", __func__); 694 goto out_elf_end; 695 } 696 697 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { 698 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR; 699 goto out_elf_end; 700 } 701 702 /* Always reject images with a mismatched build-id: */ 703 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) { 704 u8 build_id[BUILD_ID_SIZE]; 705 706 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) { 707 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; 708 goto out_elf_end; 709 } 710 711 if (!dso__build_id_equal(dso, build_id)) { 712 pr_debug("%s: build id mismatch for %s.\n", __func__, name); 713 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; 714 goto out_elf_end; 715 } 716 } 717 718 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 719 720 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", 721 NULL); 722 if (ss->symshdr.sh_type != SHT_SYMTAB) 723 ss->symtab = NULL; 724 725 ss->dynsym_idx = 0; 726 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", 727 &ss->dynsym_idx); 728 if (ss->dynshdr.sh_type != SHT_DYNSYM) 729 ss->dynsym = NULL; 730 731 ss->opdidx = 0; 732 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", 733 &ss->opdidx); 734 if (ss->opdshdr.sh_type != SHT_PROGBITS) 735 ss->opdsec = NULL; 736 737 if (dso->kernel == DSO_TYPE_USER) 738 ss->adjust_symbols = true; 739 else 740 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); 741 742 ss->name = strdup(name); 743 if (!ss->name) { 744 dso->load_errno = errno; 745 goto out_elf_end; 746 } 747 748 ss->elf = elf; 749 ss->fd = fd; 750 ss->ehdr = ehdr; 751 ss->type = type; 752 753 return 0; 754 755 out_elf_end: 756 elf_end(elf); 757 out_close: 758 close(fd); 759 return err; 760 } 761 762 /** 763 * ref_reloc_sym_not_found - has kernel relocation symbol been found. 764 * @kmap: kernel maps and relocation reference symbol 765 * 766 * This function returns %true if we are dealing with the kernel maps and the 767 * relocation reference symbol has not yet been found. Otherwise %false is 768 * returned. 769 */ 770 static bool ref_reloc_sym_not_found(struct kmap *kmap) 771 { 772 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && 773 !kmap->ref_reloc_sym->unrelocated_addr; 774 } 775 776 /** 777 * ref_reloc - kernel relocation offset. 778 * @kmap: kernel maps and relocation reference symbol 779 * 780 * This function returns the offset of kernel addresses as determined by using 781 * the relocation reference symbol i.e. if the kernel has not been relocated 782 * then the return value is zero. 783 */ 784 static u64 ref_reloc(struct kmap *kmap) 785 { 786 if (kmap && kmap->ref_reloc_sym && 787 kmap->ref_reloc_sym->unrelocated_addr) 788 return kmap->ref_reloc_sym->addr - 789 kmap->ref_reloc_sym->unrelocated_addr; 790 return 0; 791 } 792 793 void __weak arch__sym_update(struct symbol *s __maybe_unused, 794 GElf_Sym *sym __maybe_unused) { } 795 796 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, 797 struct symsrc *runtime_ss, int kmodule) 798 { 799 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; 800 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL; 801 struct map *curr_map = map; 802 struct dso *curr_dso = dso; 803 Elf_Data *symstrs, *secstrs; 804 uint32_t nr_syms; 805 int err = -1; 806 uint32_t idx; 807 GElf_Ehdr ehdr; 808 GElf_Shdr shdr; 809 GElf_Shdr tshdr; 810 Elf_Data *syms, *opddata = NULL; 811 GElf_Sym sym; 812 Elf_Scn *sec, *sec_strndx; 813 Elf *elf; 814 int nr = 0; 815 bool remap_kernel = false, adjust_kernel_syms = false; 816 817 if (kmap && !kmaps) 818 return -1; 819 820 dso->symtab_type = syms_ss->type; 821 dso->is_64_bit = syms_ss->is_64_bit; 822 dso->rel = syms_ss->ehdr.e_type == ET_REL; 823 824 /* 825 * Modules may already have symbols from kallsyms, but those symbols 826 * have the wrong values for the dso maps, so remove them. 827 */ 828 if (kmodule && syms_ss->symtab) 829 symbols__delete(&dso->symbols[map->type]); 830 831 if (!syms_ss->symtab) { 832 /* 833 * If the vmlinux is stripped, fail so we will fall back 834 * to using kallsyms. The vmlinux runtime symbols aren't 835 * of much use. 836 */ 837 if (dso->kernel) 838 goto out_elf_end; 839 840 syms_ss->symtab = syms_ss->dynsym; 841 syms_ss->symshdr = syms_ss->dynshdr; 842 } 843 844 elf = syms_ss->elf; 845 ehdr = syms_ss->ehdr; 846 sec = syms_ss->symtab; 847 shdr = syms_ss->symshdr; 848 849 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, 850 ".text", NULL)) 851 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; 852 853 if (runtime_ss->opdsec) 854 opddata = elf_rawdata(runtime_ss->opdsec, NULL); 855 856 syms = elf_getdata(sec, NULL); 857 if (syms == NULL) 858 goto out_elf_end; 859 860 sec = elf_getscn(elf, shdr.sh_link); 861 if (sec == NULL) 862 goto out_elf_end; 863 864 symstrs = elf_getdata(sec, NULL); 865 if (symstrs == NULL) 866 goto out_elf_end; 867 868 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); 869 if (sec_strndx == NULL) 870 goto out_elf_end; 871 872 secstrs = elf_getdata(sec_strndx, NULL); 873 if (secstrs == NULL) 874 goto out_elf_end; 875 876 nr_syms = shdr.sh_size / shdr.sh_entsize; 877 878 memset(&sym, 0, sizeof(sym)); 879 880 /* 881 * The kernel relocation symbol is needed in advance in order to adjust 882 * kernel maps correctly. 883 */ 884 if (ref_reloc_sym_not_found(kmap)) { 885 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 886 const char *elf_name = elf_sym__name(&sym, symstrs); 887 888 if (strcmp(elf_name, kmap->ref_reloc_sym->name)) 889 continue; 890 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; 891 map->reloc = kmap->ref_reloc_sym->addr - 892 kmap->ref_reloc_sym->unrelocated_addr; 893 break; 894 } 895 } 896 897 /* 898 * Handle any relocation of vdso necessary because older kernels 899 * attempted to prelink vdso to its virtual address. 900 */ 901 if (dso__is_vdso(dso)) 902 map->reloc = map->start - dso->text_offset; 903 904 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); 905 /* 906 * Initial kernel and module mappings do not map to the dso. For 907 * function mappings, flag the fixups. 908 */ 909 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) { 910 remap_kernel = true; 911 adjust_kernel_syms = dso->adjust_symbols; 912 } 913 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 914 struct symbol *f; 915 const char *elf_name = elf_sym__name(&sym, symstrs); 916 char *demangled = NULL; 917 int is_label = elf_sym__is_label(&sym); 918 const char *section_name; 919 bool used_opd = false; 920 921 if (!is_label && !elf_sym__is_a(&sym, map->type)) 922 continue; 923 924 /* Reject ARM ELF "mapping symbols": these aren't unique and 925 * don't identify functions, so will confuse the profile 926 * output: */ 927 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { 928 if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) 929 && (elf_name[2] == '\0' || elf_name[2] == '.')) 930 continue; 931 } 932 933 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { 934 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; 935 u64 *opd = opddata->d_buf + offset; 936 sym.st_value = DSO__SWAP(dso, u64, *opd); 937 sym.st_shndx = elf_addr_to_index(runtime_ss->elf, 938 sym.st_value); 939 used_opd = true; 940 } 941 /* 942 * When loading symbols in a data mapping, ABS symbols (which 943 * has a value of SHN_ABS in its st_shndx) failed at 944 * elf_getscn(). And it marks the loading as a failure so 945 * already loaded symbols cannot be fixed up. 946 * 947 * I'm not sure what should be done. Just ignore them for now. 948 * - Namhyung Kim 949 */ 950 if (sym.st_shndx == SHN_ABS) 951 continue; 952 953 sec = elf_getscn(runtime_ss->elf, sym.st_shndx); 954 if (!sec) 955 goto out_elf_end; 956 957 gelf_getshdr(sec, &shdr); 958 959 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type)) 960 continue; 961 962 section_name = elf_sec__name(&shdr, secstrs); 963 964 /* On ARM, symbols for thumb functions have 1 added to 965 * the symbol address as a flag - remove it */ 966 if ((ehdr.e_machine == EM_ARM) && 967 (map->type == MAP__FUNCTION) && 968 (sym.st_value & 1)) 969 --sym.st_value; 970 971 if (dso->kernel || kmodule) { 972 char dso_name[PATH_MAX]; 973 974 /* Adjust symbol to map to file offset */ 975 if (adjust_kernel_syms) 976 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 977 978 if (strcmp(section_name, 979 (curr_dso->short_name + 980 dso->short_name_len)) == 0) 981 goto new_symbol; 982 983 if (strcmp(section_name, ".text") == 0) { 984 /* 985 * The initial kernel mapping is based on 986 * kallsyms and identity maps. Overwrite it to 987 * map to the kernel dso. 988 */ 989 if (remap_kernel && dso->kernel) { 990 remap_kernel = false; 991 map->start = shdr.sh_addr + 992 ref_reloc(kmap); 993 map->end = map->start + shdr.sh_size; 994 map->pgoff = shdr.sh_offset; 995 map->map_ip = map__map_ip; 996 map->unmap_ip = map__unmap_ip; 997 /* Ensure maps are correctly ordered */ 998 if (kmaps) { 999 map__get(map); 1000 map_groups__remove(kmaps, map); 1001 map_groups__insert(kmaps, map); 1002 map__put(map); 1003 } 1004 } 1005 1006 /* 1007 * The initial module mapping is based on 1008 * /proc/modules mapped to offset zero. 1009 * Overwrite it to map to the module dso. 1010 */ 1011 if (remap_kernel && kmodule) { 1012 remap_kernel = false; 1013 map->pgoff = shdr.sh_offset; 1014 } 1015 1016 curr_map = map; 1017 curr_dso = dso; 1018 goto new_symbol; 1019 } 1020 1021 if (!kmap) 1022 goto new_symbol; 1023 1024 snprintf(dso_name, sizeof(dso_name), 1025 "%s%s", dso->short_name, section_name); 1026 1027 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name); 1028 if (curr_map == NULL) { 1029 u64 start = sym.st_value; 1030 1031 if (kmodule) 1032 start += map->start + shdr.sh_offset; 1033 1034 curr_dso = dso__new(dso_name); 1035 if (curr_dso == NULL) 1036 goto out_elf_end; 1037 curr_dso->kernel = dso->kernel; 1038 curr_dso->long_name = dso->long_name; 1039 curr_dso->long_name_len = dso->long_name_len; 1040 curr_map = map__new2(start, curr_dso, 1041 map->type); 1042 dso__put(curr_dso); 1043 if (curr_map == NULL) { 1044 goto out_elf_end; 1045 } 1046 if (adjust_kernel_syms) { 1047 curr_map->start = shdr.sh_addr + 1048 ref_reloc(kmap); 1049 curr_map->end = curr_map->start + 1050 shdr.sh_size; 1051 curr_map->pgoff = shdr.sh_offset; 1052 } else { 1053 curr_map->map_ip = identity__map_ip; 1054 curr_map->unmap_ip = identity__map_ip; 1055 } 1056 curr_dso->symtab_type = dso->symtab_type; 1057 map_groups__insert(kmaps, curr_map); 1058 /* 1059 * Add it before we drop the referece to curr_map, 1060 * i.e. while we still are sure to have a reference 1061 * to this DSO via curr_map->dso. 1062 */ 1063 dsos__add(&map->groups->machine->dsos, curr_dso); 1064 /* kmaps already got it */ 1065 map__put(curr_map); 1066 dso__set_loaded(curr_dso, map->type); 1067 } else 1068 curr_dso = curr_map->dso; 1069 1070 goto new_symbol; 1071 } 1072 1073 if ((used_opd && runtime_ss->adjust_symbols) 1074 || (!used_opd && syms_ss->adjust_symbols)) { 1075 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1076 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__, 1077 (u64)sym.st_value, (u64)shdr.sh_addr, 1078 (u64)shdr.sh_offset); 1079 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 1080 } 1081 new_symbol: 1082 demangled = demangle_sym(dso, kmodule, elf_name); 1083 if (demangled != NULL) 1084 elf_name = demangled; 1085 1086 f = symbol__new(sym.st_value, sym.st_size, 1087 GELF_ST_BIND(sym.st_info), elf_name); 1088 free(demangled); 1089 if (!f) 1090 goto out_elf_end; 1091 1092 arch__sym_update(f, &sym); 1093 1094 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel); 1095 nr++; 1096 } 1097 1098 /* 1099 * For misannotated, zeroed, ASM function sizes. 1100 */ 1101 if (nr > 0) { 1102 symbols__fixup_end(&dso->symbols[map->type]); 1103 symbols__fixup_duplicate(&dso->symbols[map->type]); 1104 if (kmap) { 1105 /* 1106 * We need to fixup this here too because we create new 1107 * maps here, for things like vsyscall sections. 1108 */ 1109 __map_groups__fixup_end(kmaps, map->type); 1110 } 1111 } 1112 err = nr; 1113 out_elf_end: 1114 return err; 1115 } 1116 1117 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) 1118 { 1119 GElf_Phdr phdr; 1120 size_t i, phdrnum; 1121 int err; 1122 u64 sz; 1123 1124 if (elf_getphdrnum(elf, &phdrnum)) 1125 return -1; 1126 1127 for (i = 0; i < phdrnum; i++) { 1128 if (gelf_getphdr(elf, i, &phdr) == NULL) 1129 return -1; 1130 if (phdr.p_type != PT_LOAD) 1131 continue; 1132 if (exe) { 1133 if (!(phdr.p_flags & PF_X)) 1134 continue; 1135 } else { 1136 if (!(phdr.p_flags & PF_R)) 1137 continue; 1138 } 1139 sz = min(phdr.p_memsz, phdr.p_filesz); 1140 if (!sz) 1141 continue; 1142 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); 1143 if (err) 1144 return err; 1145 } 1146 return 0; 1147 } 1148 1149 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, 1150 bool *is_64_bit) 1151 { 1152 int err; 1153 Elf *elf; 1154 1155 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1156 if (elf == NULL) 1157 return -1; 1158 1159 if (is_64_bit) 1160 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1161 1162 err = elf_read_maps(elf, exe, mapfn, data); 1163 1164 elf_end(elf); 1165 return err; 1166 } 1167 1168 enum dso_type dso__type_fd(int fd) 1169 { 1170 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 1171 GElf_Ehdr ehdr; 1172 Elf_Kind ek; 1173 Elf *elf; 1174 1175 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1176 if (elf == NULL) 1177 goto out; 1178 1179 ek = elf_kind(elf); 1180 if (ek != ELF_K_ELF) 1181 goto out_end; 1182 1183 if (gelf_getclass(elf) == ELFCLASS64) { 1184 dso_type = DSO__TYPE_64BIT; 1185 goto out_end; 1186 } 1187 1188 if (gelf_getehdr(elf, &ehdr) == NULL) 1189 goto out_end; 1190 1191 if (ehdr.e_machine == EM_X86_64) 1192 dso_type = DSO__TYPE_X32BIT; 1193 else 1194 dso_type = DSO__TYPE_32BIT; 1195 out_end: 1196 elf_end(elf); 1197 out: 1198 return dso_type; 1199 } 1200 1201 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) 1202 { 1203 ssize_t r; 1204 size_t n; 1205 int err = -1; 1206 char *buf = malloc(page_size); 1207 1208 if (buf == NULL) 1209 return -1; 1210 1211 if (lseek(to, to_offs, SEEK_SET) != to_offs) 1212 goto out; 1213 1214 if (lseek(from, from_offs, SEEK_SET) != from_offs) 1215 goto out; 1216 1217 while (len) { 1218 n = page_size; 1219 if (len < n) 1220 n = len; 1221 /* Use read because mmap won't work on proc files */ 1222 r = read(from, buf, n); 1223 if (r < 0) 1224 goto out; 1225 if (!r) 1226 break; 1227 n = r; 1228 r = write(to, buf, n); 1229 if (r < 0) 1230 goto out; 1231 if ((size_t)r != n) 1232 goto out; 1233 len -= n; 1234 } 1235 1236 err = 0; 1237 out: 1238 free(buf); 1239 return err; 1240 } 1241 1242 struct kcore { 1243 int fd; 1244 int elfclass; 1245 Elf *elf; 1246 GElf_Ehdr ehdr; 1247 }; 1248 1249 static int kcore__open(struct kcore *kcore, const char *filename) 1250 { 1251 GElf_Ehdr *ehdr; 1252 1253 kcore->fd = open(filename, O_RDONLY); 1254 if (kcore->fd == -1) 1255 return -1; 1256 1257 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); 1258 if (!kcore->elf) 1259 goto out_close; 1260 1261 kcore->elfclass = gelf_getclass(kcore->elf); 1262 if (kcore->elfclass == ELFCLASSNONE) 1263 goto out_end; 1264 1265 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); 1266 if (!ehdr) 1267 goto out_end; 1268 1269 return 0; 1270 1271 out_end: 1272 elf_end(kcore->elf); 1273 out_close: 1274 close(kcore->fd); 1275 return -1; 1276 } 1277 1278 static int kcore__init(struct kcore *kcore, char *filename, int elfclass, 1279 bool temp) 1280 { 1281 kcore->elfclass = elfclass; 1282 1283 if (temp) 1284 kcore->fd = mkstemp(filename); 1285 else 1286 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); 1287 if (kcore->fd == -1) 1288 return -1; 1289 1290 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); 1291 if (!kcore->elf) 1292 goto out_close; 1293 1294 if (!gelf_newehdr(kcore->elf, elfclass)) 1295 goto out_end; 1296 1297 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); 1298 1299 return 0; 1300 1301 out_end: 1302 elf_end(kcore->elf); 1303 out_close: 1304 close(kcore->fd); 1305 unlink(filename); 1306 return -1; 1307 } 1308 1309 static void kcore__close(struct kcore *kcore) 1310 { 1311 elf_end(kcore->elf); 1312 close(kcore->fd); 1313 } 1314 1315 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) 1316 { 1317 GElf_Ehdr *ehdr = &to->ehdr; 1318 GElf_Ehdr *kehdr = &from->ehdr; 1319 1320 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); 1321 ehdr->e_type = kehdr->e_type; 1322 ehdr->e_machine = kehdr->e_machine; 1323 ehdr->e_version = kehdr->e_version; 1324 ehdr->e_entry = 0; 1325 ehdr->e_shoff = 0; 1326 ehdr->e_flags = kehdr->e_flags; 1327 ehdr->e_phnum = count; 1328 ehdr->e_shentsize = 0; 1329 ehdr->e_shnum = 0; 1330 ehdr->e_shstrndx = 0; 1331 1332 if (from->elfclass == ELFCLASS32) { 1333 ehdr->e_phoff = sizeof(Elf32_Ehdr); 1334 ehdr->e_ehsize = sizeof(Elf32_Ehdr); 1335 ehdr->e_phentsize = sizeof(Elf32_Phdr); 1336 } else { 1337 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1338 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1339 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1340 } 1341 1342 if (!gelf_update_ehdr(to->elf, ehdr)) 1343 return -1; 1344 1345 if (!gelf_newphdr(to->elf, count)) 1346 return -1; 1347 1348 return 0; 1349 } 1350 1351 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, 1352 u64 addr, u64 len) 1353 { 1354 GElf_Phdr phdr = { 1355 .p_type = PT_LOAD, 1356 .p_flags = PF_R | PF_W | PF_X, 1357 .p_offset = offset, 1358 .p_vaddr = addr, 1359 .p_paddr = 0, 1360 .p_filesz = len, 1361 .p_memsz = len, 1362 .p_align = page_size, 1363 }; 1364 1365 if (!gelf_update_phdr(kcore->elf, idx, &phdr)) 1366 return -1; 1367 1368 return 0; 1369 } 1370 1371 static off_t kcore__write(struct kcore *kcore) 1372 { 1373 return elf_update(kcore->elf, ELF_C_WRITE); 1374 } 1375 1376 struct phdr_data { 1377 off_t offset; 1378 u64 addr; 1379 u64 len; 1380 }; 1381 1382 struct kcore_copy_info { 1383 u64 stext; 1384 u64 etext; 1385 u64 first_symbol; 1386 u64 last_symbol; 1387 u64 first_module; 1388 u64 last_module_symbol; 1389 struct phdr_data kernel_map; 1390 struct phdr_data modules_map; 1391 }; 1392 1393 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 1394 u64 start) 1395 { 1396 struct kcore_copy_info *kci = arg; 1397 1398 if (!symbol_type__is_a(type, MAP__FUNCTION)) 1399 return 0; 1400 1401 if (strchr(name, '[')) { 1402 if (start > kci->last_module_symbol) 1403 kci->last_module_symbol = start; 1404 return 0; 1405 } 1406 1407 if (!kci->first_symbol || start < kci->first_symbol) 1408 kci->first_symbol = start; 1409 1410 if (!kci->last_symbol || start > kci->last_symbol) 1411 kci->last_symbol = start; 1412 1413 if (!strcmp(name, "_stext")) { 1414 kci->stext = start; 1415 return 0; 1416 } 1417 1418 if (!strcmp(name, "_etext")) { 1419 kci->etext = start; 1420 return 0; 1421 } 1422 1423 return 0; 1424 } 1425 1426 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, 1427 const char *dir) 1428 { 1429 char kallsyms_filename[PATH_MAX]; 1430 1431 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); 1432 1433 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) 1434 return -1; 1435 1436 if (kallsyms__parse(kallsyms_filename, kci, 1437 kcore_copy__process_kallsyms) < 0) 1438 return -1; 1439 1440 return 0; 1441 } 1442 1443 static int kcore_copy__process_modules(void *arg, 1444 const char *name __maybe_unused, 1445 u64 start) 1446 { 1447 struct kcore_copy_info *kci = arg; 1448 1449 if (!kci->first_module || start < kci->first_module) 1450 kci->first_module = start; 1451 1452 return 0; 1453 } 1454 1455 static int kcore_copy__parse_modules(struct kcore_copy_info *kci, 1456 const char *dir) 1457 { 1458 char modules_filename[PATH_MAX]; 1459 1460 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); 1461 1462 if (symbol__restricted_filename(modules_filename, "/proc/modules")) 1463 return -1; 1464 1465 if (modules__parse(modules_filename, kci, 1466 kcore_copy__process_modules) < 0) 1467 return -1; 1468 1469 return 0; 1470 } 1471 1472 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff, 1473 u64 s, u64 e) 1474 { 1475 if (p->addr || s < start || s >= end) 1476 return; 1477 1478 p->addr = s; 1479 p->offset = (s - start) + pgoff; 1480 p->len = e < end ? e - s : end - s; 1481 } 1482 1483 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) 1484 { 1485 struct kcore_copy_info *kci = data; 1486 u64 end = start + len; 1487 1488 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext, 1489 kci->etext); 1490 1491 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module, 1492 kci->last_module_symbol); 1493 1494 return 0; 1495 } 1496 1497 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) 1498 { 1499 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) 1500 return -1; 1501 1502 return 0; 1503 } 1504 1505 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 1506 Elf *elf) 1507 { 1508 if (kcore_copy__parse_kallsyms(kci, dir)) 1509 return -1; 1510 1511 if (kcore_copy__parse_modules(kci, dir)) 1512 return -1; 1513 1514 if (kci->stext) 1515 kci->stext = round_down(kci->stext, page_size); 1516 else 1517 kci->stext = round_down(kci->first_symbol, page_size); 1518 1519 if (kci->etext) { 1520 kci->etext = round_up(kci->etext, page_size); 1521 } else if (kci->last_symbol) { 1522 kci->etext = round_up(kci->last_symbol, page_size); 1523 kci->etext += page_size; 1524 } 1525 1526 kci->first_module = round_down(kci->first_module, page_size); 1527 1528 if (kci->last_module_symbol) { 1529 kci->last_module_symbol = round_up(kci->last_module_symbol, 1530 page_size); 1531 kci->last_module_symbol += page_size; 1532 } 1533 1534 if (!kci->stext || !kci->etext) 1535 return -1; 1536 1537 if (kci->first_module && !kci->last_module_symbol) 1538 return -1; 1539 1540 return kcore_copy__read_maps(kci, elf); 1541 } 1542 1543 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, 1544 const char *name) 1545 { 1546 char from_filename[PATH_MAX]; 1547 char to_filename[PATH_MAX]; 1548 1549 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1550 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1551 1552 return copyfile_mode(from_filename, to_filename, 0400); 1553 } 1554 1555 static int kcore_copy__unlink(const char *dir, const char *name) 1556 { 1557 char filename[PATH_MAX]; 1558 1559 scnprintf(filename, PATH_MAX, "%s/%s", dir, name); 1560 1561 return unlink(filename); 1562 } 1563 1564 static int kcore_copy__compare_fds(int from, int to) 1565 { 1566 char *buf_from; 1567 char *buf_to; 1568 ssize_t ret; 1569 size_t len; 1570 int err = -1; 1571 1572 buf_from = malloc(page_size); 1573 buf_to = malloc(page_size); 1574 if (!buf_from || !buf_to) 1575 goto out; 1576 1577 while (1) { 1578 /* Use read because mmap won't work on proc files */ 1579 ret = read(from, buf_from, page_size); 1580 if (ret < 0) 1581 goto out; 1582 1583 if (!ret) 1584 break; 1585 1586 len = ret; 1587 1588 if (readn(to, buf_to, len) != (int)len) 1589 goto out; 1590 1591 if (memcmp(buf_from, buf_to, len)) 1592 goto out; 1593 } 1594 1595 err = 0; 1596 out: 1597 free(buf_to); 1598 free(buf_from); 1599 return err; 1600 } 1601 1602 static int kcore_copy__compare_files(const char *from_filename, 1603 const char *to_filename) 1604 { 1605 int from, to, err = -1; 1606 1607 from = open(from_filename, O_RDONLY); 1608 if (from < 0) 1609 return -1; 1610 1611 to = open(to_filename, O_RDONLY); 1612 if (to < 0) 1613 goto out_close_from; 1614 1615 err = kcore_copy__compare_fds(from, to); 1616 1617 close(to); 1618 out_close_from: 1619 close(from); 1620 return err; 1621 } 1622 1623 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, 1624 const char *name) 1625 { 1626 char from_filename[PATH_MAX]; 1627 char to_filename[PATH_MAX]; 1628 1629 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1630 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1631 1632 return kcore_copy__compare_files(from_filename, to_filename); 1633 } 1634 1635 /** 1636 * kcore_copy - copy kallsyms, modules and kcore from one directory to another. 1637 * @from_dir: from directory 1638 * @to_dir: to directory 1639 * 1640 * This function copies kallsyms, modules and kcore files from one directory to 1641 * another. kallsyms and modules are copied entirely. Only code segments are 1642 * copied from kcore. It is assumed that two segments suffice: one for the 1643 * kernel proper and one for all the modules. The code segments are determined 1644 * from kallsyms and modules files. The kernel map starts at _stext or the 1645 * lowest function symbol, and ends at _etext or the highest function symbol. 1646 * The module map starts at the lowest module address and ends at the highest 1647 * module symbol. Start addresses are rounded down to the nearest page. End 1648 * addresses are rounded up to the nearest page. An extra page is added to the 1649 * highest kernel symbol and highest module symbol to, hopefully, encompass that 1650 * symbol too. Because it contains only code sections, the resulting kcore is 1651 * unusual. One significant peculiarity is that the mapping (start -> pgoff) 1652 * is not the same for the kernel map and the modules map. That happens because 1653 * the data is copied adjacently whereas the original kcore has gaps. Finally, 1654 * kallsyms and modules files are compared with their copies to check that 1655 * modules have not been loaded or unloaded while the copies were taking place. 1656 * 1657 * Return: %0 on success, %-1 on failure. 1658 */ 1659 int kcore_copy(const char *from_dir, const char *to_dir) 1660 { 1661 struct kcore kcore; 1662 struct kcore extract; 1663 size_t count = 2; 1664 int idx = 0, err = -1; 1665 off_t offset = page_size, sz, modules_offset = 0; 1666 struct kcore_copy_info kci = { .stext = 0, }; 1667 char kcore_filename[PATH_MAX]; 1668 char extract_filename[PATH_MAX]; 1669 1670 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) 1671 return -1; 1672 1673 if (kcore_copy__copy_file(from_dir, to_dir, "modules")) 1674 goto out_unlink_kallsyms; 1675 1676 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); 1677 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); 1678 1679 if (kcore__open(&kcore, kcore_filename)) 1680 goto out_unlink_modules; 1681 1682 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) 1683 goto out_kcore_close; 1684 1685 if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) 1686 goto out_kcore_close; 1687 1688 if (!kci.modules_map.addr) 1689 count -= 1; 1690 1691 if (kcore__copy_hdr(&kcore, &extract, count)) 1692 goto out_extract_close; 1693 1694 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr, 1695 kci.kernel_map.len)) 1696 goto out_extract_close; 1697 1698 if (kci.modules_map.addr) { 1699 modules_offset = offset + kci.kernel_map.len; 1700 if (kcore__add_phdr(&extract, idx, modules_offset, 1701 kci.modules_map.addr, kci.modules_map.len)) 1702 goto out_extract_close; 1703 } 1704 1705 sz = kcore__write(&extract); 1706 if (sz < 0 || sz > offset) 1707 goto out_extract_close; 1708 1709 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset, 1710 kci.kernel_map.len)) 1711 goto out_extract_close; 1712 1713 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset, 1714 extract.fd, modules_offset, 1715 kci.modules_map.len)) 1716 goto out_extract_close; 1717 1718 if (kcore_copy__compare_file(from_dir, to_dir, "modules")) 1719 goto out_extract_close; 1720 1721 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) 1722 goto out_extract_close; 1723 1724 err = 0; 1725 1726 out_extract_close: 1727 kcore__close(&extract); 1728 if (err) 1729 unlink(extract_filename); 1730 out_kcore_close: 1731 kcore__close(&kcore); 1732 out_unlink_modules: 1733 if (err) 1734 kcore_copy__unlink(to_dir, "modules"); 1735 out_unlink_kallsyms: 1736 if (err) 1737 kcore_copy__unlink(to_dir, "kallsyms"); 1738 1739 return err; 1740 } 1741 1742 int kcore_extract__create(struct kcore_extract *kce) 1743 { 1744 struct kcore kcore; 1745 struct kcore extract; 1746 size_t count = 1; 1747 int idx = 0, err = -1; 1748 off_t offset = page_size, sz; 1749 1750 if (kcore__open(&kcore, kce->kcore_filename)) 1751 return -1; 1752 1753 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); 1754 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) 1755 goto out_kcore_close; 1756 1757 if (kcore__copy_hdr(&kcore, &extract, count)) 1758 goto out_extract_close; 1759 1760 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) 1761 goto out_extract_close; 1762 1763 sz = kcore__write(&extract); 1764 if (sz < 0 || sz > offset) 1765 goto out_extract_close; 1766 1767 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) 1768 goto out_extract_close; 1769 1770 err = 0; 1771 1772 out_extract_close: 1773 kcore__close(&extract); 1774 if (err) 1775 unlink(kce->extract_filename); 1776 out_kcore_close: 1777 kcore__close(&kcore); 1778 1779 return err; 1780 } 1781 1782 void kcore_extract__delete(struct kcore_extract *kce) 1783 { 1784 unlink(kce->extract_filename); 1785 } 1786 1787 #ifdef HAVE_GELF_GETNOTE_SUPPORT 1788 /** 1789 * populate_sdt_note : Parse raw data and identify SDT note 1790 * @elf: elf of the opened file 1791 * @data: raw data of a section with description offset applied 1792 * @len: note description size 1793 * @type: type of the note 1794 * @sdt_notes: List to add the SDT note 1795 * 1796 * Responsible for parsing the @data in section .note.stapsdt in @elf and 1797 * if its an SDT note, it appends to @sdt_notes list. 1798 */ 1799 static int populate_sdt_note(Elf **elf, const char *data, size_t len, 1800 struct list_head *sdt_notes) 1801 { 1802 const char *provider, *name, *args; 1803 struct sdt_note *tmp = NULL; 1804 GElf_Ehdr ehdr; 1805 GElf_Addr base_off = 0; 1806 GElf_Shdr shdr; 1807 int ret = -EINVAL; 1808 1809 union { 1810 Elf64_Addr a64[NR_ADDR]; 1811 Elf32_Addr a32[NR_ADDR]; 1812 } buf; 1813 1814 Elf_Data dst = { 1815 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, 1816 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), 1817 .d_off = 0, .d_align = 0 1818 }; 1819 Elf_Data src = { 1820 .d_buf = (void *) data, .d_type = ELF_T_ADDR, 1821 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, 1822 .d_align = 0 1823 }; 1824 1825 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); 1826 if (!tmp) { 1827 ret = -ENOMEM; 1828 goto out_err; 1829 } 1830 1831 INIT_LIST_HEAD(&tmp->note_list); 1832 1833 if (len < dst.d_size + 3) 1834 goto out_free_note; 1835 1836 /* Translation from file representation to memory representation */ 1837 if (gelf_xlatetom(*elf, &dst, &src, 1838 elf_getident(*elf, NULL)[EI_DATA]) == NULL) { 1839 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); 1840 goto out_free_note; 1841 } 1842 1843 /* Populate the fields of sdt_note */ 1844 provider = data + dst.d_size; 1845 1846 name = (const char *)memchr(provider, '\0', data + len - provider); 1847 if (name++ == NULL) 1848 goto out_free_note; 1849 1850 tmp->provider = strdup(provider); 1851 if (!tmp->provider) { 1852 ret = -ENOMEM; 1853 goto out_free_note; 1854 } 1855 tmp->name = strdup(name); 1856 if (!tmp->name) { 1857 ret = -ENOMEM; 1858 goto out_free_prov; 1859 } 1860 1861 args = memchr(name, '\0', data + len - name); 1862 1863 /* 1864 * There is no argument if: 1865 * - We reached the end of the note; 1866 * - There is not enough room to hold a potential string; 1867 * - The argument string is empty or just contains ':'. 1868 */ 1869 if (args == NULL || data + len - args < 2 || 1870 args[1] == ':' || args[1] == '\0') 1871 tmp->args = NULL; 1872 else { 1873 tmp->args = strdup(++args); 1874 if (!tmp->args) { 1875 ret = -ENOMEM; 1876 goto out_free_name; 1877 } 1878 } 1879 1880 if (gelf_getclass(*elf) == ELFCLASS32) { 1881 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); 1882 tmp->bit32 = true; 1883 } else { 1884 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); 1885 tmp->bit32 = false; 1886 } 1887 1888 if (!gelf_getehdr(*elf, &ehdr)) { 1889 pr_debug("%s : cannot get elf header.\n", __func__); 1890 ret = -EBADF; 1891 goto out_free_args; 1892 } 1893 1894 /* Adjust the prelink effect : 1895 * Find out the .stapsdt.base section. 1896 * This scn will help us to handle prelinking (if present). 1897 * Compare the retrieved file offset of the base section with the 1898 * base address in the description of the SDT note. If its different, 1899 * then accordingly, adjust the note location. 1900 */ 1901 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) { 1902 base_off = shdr.sh_offset; 1903 if (base_off) { 1904 if (tmp->bit32) 1905 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off - 1906 tmp->addr.a32[1]; 1907 else 1908 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off - 1909 tmp->addr.a64[1]; 1910 } 1911 } 1912 1913 list_add_tail(&tmp->note_list, sdt_notes); 1914 return 0; 1915 1916 out_free_args: 1917 free(tmp->args); 1918 out_free_name: 1919 free(tmp->name); 1920 out_free_prov: 1921 free(tmp->provider); 1922 out_free_note: 1923 free(tmp); 1924 out_err: 1925 return ret; 1926 } 1927 1928 /** 1929 * construct_sdt_notes_list : constructs a list of SDT notes 1930 * @elf : elf to look into 1931 * @sdt_notes : empty list_head 1932 * 1933 * Scans the sections in 'elf' for the section 1934 * .note.stapsdt. It, then calls populate_sdt_note to find 1935 * out the SDT events and populates the 'sdt_notes'. 1936 */ 1937 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) 1938 { 1939 GElf_Ehdr ehdr; 1940 Elf_Scn *scn = NULL; 1941 Elf_Data *data; 1942 GElf_Shdr shdr; 1943 size_t shstrndx, next; 1944 GElf_Nhdr nhdr; 1945 size_t name_off, desc_off, offset; 1946 int ret = 0; 1947 1948 if (gelf_getehdr(elf, &ehdr) == NULL) { 1949 ret = -EBADF; 1950 goto out_ret; 1951 } 1952 if (elf_getshdrstrndx(elf, &shstrndx) != 0) { 1953 ret = -EBADF; 1954 goto out_ret; 1955 } 1956 1957 /* Look for the required section */ 1958 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); 1959 if (!scn) { 1960 ret = -ENOENT; 1961 goto out_ret; 1962 } 1963 1964 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { 1965 ret = -ENOENT; 1966 goto out_ret; 1967 } 1968 1969 data = elf_getdata(scn, NULL); 1970 1971 /* Get the SDT notes */ 1972 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, 1973 &desc_off)) > 0; offset = next) { 1974 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && 1975 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, 1976 sizeof(SDT_NOTE_NAME))) { 1977 /* Check the type of the note */ 1978 if (nhdr.n_type != SDT_NOTE_TYPE) 1979 goto out_ret; 1980 1981 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), 1982 nhdr.n_descsz, sdt_notes); 1983 if (ret < 0) 1984 goto out_ret; 1985 } 1986 } 1987 if (list_empty(sdt_notes)) 1988 ret = -ENOENT; 1989 1990 out_ret: 1991 return ret; 1992 } 1993 1994 /** 1995 * get_sdt_note_list : Wrapper to construct a list of sdt notes 1996 * @head : empty list_head 1997 * @target : file to find SDT notes from 1998 * 1999 * This opens the file, initializes 2000 * the ELF and then calls construct_sdt_notes_list. 2001 */ 2002 int get_sdt_note_list(struct list_head *head, const char *target) 2003 { 2004 Elf *elf; 2005 int fd, ret; 2006 2007 fd = open(target, O_RDONLY); 2008 if (fd < 0) 2009 return -EBADF; 2010 2011 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 2012 if (!elf) { 2013 ret = -EBADF; 2014 goto out_close; 2015 } 2016 ret = construct_sdt_notes_list(elf, head); 2017 elf_end(elf); 2018 out_close: 2019 close(fd); 2020 return ret; 2021 } 2022 2023 /** 2024 * cleanup_sdt_note_list : free the sdt notes' list 2025 * @sdt_notes: sdt notes' list 2026 * 2027 * Free up the SDT notes in @sdt_notes. 2028 * Returns the number of SDT notes free'd. 2029 */ 2030 int cleanup_sdt_note_list(struct list_head *sdt_notes) 2031 { 2032 struct sdt_note *tmp, *pos; 2033 int nr_free = 0; 2034 2035 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { 2036 list_del(&pos->note_list); 2037 free(pos->name); 2038 free(pos->provider); 2039 free(pos); 2040 nr_free++; 2041 } 2042 return nr_free; 2043 } 2044 2045 /** 2046 * sdt_notes__get_count: Counts the number of sdt events 2047 * @start: list_head to sdt_notes list 2048 * 2049 * Returns the number of SDT notes in a list 2050 */ 2051 int sdt_notes__get_count(struct list_head *start) 2052 { 2053 struct sdt_note *sdt_ptr; 2054 int count = 0; 2055 2056 list_for_each_entry(sdt_ptr, start, note_list) 2057 count++; 2058 return count; 2059 } 2060 #endif 2061 2062 void symbol__elf_init(void) 2063 { 2064 elf_version(EV_CURRENT); 2065 } 2066