1 // SPDX-License-Identifier: GPL-2.0 2 #include <fcntl.h> 3 #include <stdio.h> 4 #include <errno.h> 5 #include <stdlib.h> 6 #include <string.h> 7 #include <unistd.h> 8 #include <inttypes.h> 9 10 #include "dso.h" 11 #include "map.h" 12 #include "maps.h" 13 #include "symbol.h" 14 #include "symsrc.h" 15 #include "demangle-ocaml.h" 16 #include "demangle-java.h" 17 #include "demangle-rust.h" 18 #include "machine.h" 19 #include "vdso.h" 20 #include "debug.h" 21 #include "util/copyfile.h" 22 #include <linux/ctype.h> 23 #include <linux/kernel.h> 24 #include <linux/zalloc.h> 25 #include <symbol/kallsyms.h> 26 #include <internal/lib.h> 27 28 #ifndef EM_AARCH64 29 #define EM_AARCH64 183 /* ARM 64 bit */ 30 #endif 31 32 #ifndef ELF32_ST_VISIBILITY 33 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03) 34 #endif 35 36 /* For ELF64 the definitions are the same. */ 37 #ifndef ELF64_ST_VISIBILITY 38 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o) 39 #endif 40 41 /* How to extract information held in the st_other field. */ 42 #ifndef GELF_ST_VISIBILITY 43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val) 44 #endif 45 46 typedef Elf64_Nhdr GElf_Nhdr; 47 48 #ifndef DMGL_PARAMS 49 #define DMGL_NO_OPTS 0 /* For readability... */ 50 #define DMGL_PARAMS (1 << 0) /* Include function args */ 51 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ 52 #endif 53 54 #ifdef HAVE_LIBBFD_SUPPORT 55 #define PACKAGE 'perf' 56 #include <bfd.h> 57 #else 58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT 59 extern char *cplus_demangle(const char *, int); 60 61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i) 62 { 63 return cplus_demangle(c, i); 64 } 65 #else 66 #ifdef NO_DEMANGLE 67 static inline char *bfd_demangle(void __maybe_unused *v, 68 const char __maybe_unused *c, 69 int __maybe_unused i) 70 { 71 return NULL; 72 } 73 #endif 74 #endif 75 #endif 76 77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT 78 static int elf_getphdrnum(Elf *elf, size_t *dst) 79 { 80 GElf_Ehdr gehdr; 81 GElf_Ehdr *ehdr; 82 83 ehdr = gelf_getehdr(elf, &gehdr); 84 if (!ehdr) 85 return -1; 86 87 *dst = ehdr->e_phnum; 88 89 return 0; 90 } 91 #endif 92 93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT 94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused) 95 { 96 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__); 97 return -1; 98 } 99 #endif 100 101 #ifndef NT_GNU_BUILD_ID 102 #define NT_GNU_BUILD_ID 3 103 #endif 104 105 /** 106 * elf_symtab__for_each_symbol - iterate thru all the symbols 107 * 108 * @syms: struct elf_symtab instance to iterate 109 * @idx: uint32_t idx 110 * @sym: GElf_Sym iterator 111 */ 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \ 113 for (idx = 0, gelf_getsym(syms, idx, &sym);\ 114 idx < nr_syms; \ 115 idx++, gelf_getsym(syms, idx, &sym)) 116 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym) 118 { 119 return GELF_ST_TYPE(sym->st_info); 120 } 121 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym) 123 { 124 return GELF_ST_VISIBILITY(sym->st_other); 125 } 126 127 #ifndef STT_GNU_IFUNC 128 #define STT_GNU_IFUNC 10 129 #endif 130 131 static inline int elf_sym__is_function(const GElf_Sym *sym) 132 { 133 return (elf_sym__type(sym) == STT_FUNC || 134 elf_sym__type(sym) == STT_GNU_IFUNC) && 135 sym->st_name != 0 && 136 sym->st_shndx != SHN_UNDEF; 137 } 138 139 static inline bool elf_sym__is_object(const GElf_Sym *sym) 140 { 141 return elf_sym__type(sym) == STT_OBJECT && 142 sym->st_name != 0 && 143 sym->st_shndx != SHN_UNDEF; 144 } 145 146 static inline int elf_sym__is_label(const GElf_Sym *sym) 147 { 148 return elf_sym__type(sym) == STT_NOTYPE && 149 sym->st_name != 0 && 150 sym->st_shndx != SHN_UNDEF && 151 sym->st_shndx != SHN_ABS && 152 elf_sym__visibility(sym) != STV_HIDDEN && 153 elf_sym__visibility(sym) != STV_INTERNAL; 154 } 155 156 static bool elf_sym__filter(GElf_Sym *sym) 157 { 158 return elf_sym__is_function(sym) || elf_sym__is_object(sym); 159 } 160 161 static inline const char *elf_sym__name(const GElf_Sym *sym, 162 const Elf_Data *symstrs) 163 { 164 return symstrs->d_buf + sym->st_name; 165 } 166 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr, 168 const Elf_Data *secstrs) 169 { 170 return secstrs->d_buf + shdr->sh_name; 171 } 172 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr, 174 const Elf_Data *secstrs) 175 { 176 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL; 177 } 178 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr, 180 const Elf_Data *secstrs) 181 { 182 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL; 183 } 184 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs) 186 { 187 return elf_sec__is_text(shdr, secstrs) || 188 elf_sec__is_data(shdr, secstrs); 189 } 190 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) 192 { 193 Elf_Scn *sec = NULL; 194 GElf_Shdr shdr; 195 size_t cnt = 1; 196 197 while ((sec = elf_nextscn(elf, sec)) != NULL) { 198 gelf_getshdr(sec, &shdr); 199 200 if ((addr >= shdr.sh_addr) && 201 (addr < (shdr.sh_addr + shdr.sh_size))) 202 return cnt; 203 204 ++cnt; 205 } 206 207 return -1; 208 } 209 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, 211 GElf_Shdr *shp, const char *name, size_t *idx) 212 { 213 Elf_Scn *sec = NULL; 214 size_t cnt = 1; 215 216 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 217 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) 218 return NULL; 219 220 while ((sec = elf_nextscn(elf, sec)) != NULL) { 221 char *str; 222 223 gelf_getshdr(sec, shp); 224 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); 225 if (str && !strcmp(name, str)) { 226 if (idx) 227 *idx = cnt; 228 return sec; 229 } 230 ++cnt; 231 } 232 233 return NULL; 234 } 235 236 bool filename__has_section(const char *filename, const char *sec) 237 { 238 int fd; 239 Elf *elf; 240 GElf_Ehdr ehdr; 241 GElf_Shdr shdr; 242 bool found = false; 243 244 fd = open(filename, O_RDONLY); 245 if (fd < 0) 246 return false; 247 248 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 249 if (elf == NULL) 250 goto out; 251 252 if (gelf_getehdr(elf, &ehdr) == NULL) 253 goto elf_out; 254 255 found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL); 256 257 elf_out: 258 elf_end(elf); 259 out: 260 close(fd); 261 return found; 262 } 263 264 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr) 265 { 266 size_t i, phdrnum; 267 u64 sz; 268 269 if (elf_getphdrnum(elf, &phdrnum)) 270 return -1; 271 272 for (i = 0; i < phdrnum; i++) { 273 if (gelf_getphdr(elf, i, phdr) == NULL) 274 return -1; 275 276 if (phdr->p_type != PT_LOAD) 277 continue; 278 279 sz = max(phdr->p_memsz, phdr->p_filesz); 280 if (!sz) 281 continue; 282 283 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz)) 284 return 0; 285 } 286 287 /* Not found any valid program header */ 288 return -1; 289 } 290 291 static bool want_demangle(bool is_kernel_sym) 292 { 293 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle; 294 } 295 296 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 297 { 298 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS; 299 char *demangled = NULL; 300 301 /* 302 * We need to figure out if the object was created from C++ sources 303 * DWARF DW_compile_unit has this, but we don't always have access 304 * to it... 305 */ 306 if (!want_demangle(dso->kernel || kmodule)) 307 return demangled; 308 309 demangled = bfd_demangle(NULL, elf_name, demangle_flags); 310 if (demangled == NULL) { 311 demangled = ocaml_demangle_sym(elf_name); 312 if (demangled == NULL) { 313 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET); 314 } 315 } 316 else if (rust_is_mangled(demangled)) 317 /* 318 * Input to Rust demangling is the BFD-demangled 319 * name which it Rust-demangles in place. 320 */ 321 rust_demangle_sym(demangled); 322 323 return demangled; 324 } 325 326 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \ 327 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \ 328 idx < nr_entries; \ 329 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem)) 330 331 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \ 332 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \ 333 idx < nr_entries; \ 334 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem)) 335 336 /* 337 * We need to check if we have a .dynsym, so that we can handle the 338 * .plt, synthesizing its symbols, that aren't on the symtabs (be it 339 * .dynsym or .symtab). 340 * And always look at the original dso, not at debuginfo packages, that 341 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS). 342 */ 343 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) 344 { 345 uint32_t nr_rel_entries, idx; 346 GElf_Sym sym; 347 u64 plt_offset, plt_header_size, plt_entry_size; 348 GElf_Shdr shdr_plt; 349 struct symbol *f; 350 GElf_Shdr shdr_rel_plt, shdr_dynsym; 351 Elf_Data *reldata, *syms, *symstrs; 352 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym; 353 size_t dynsym_idx; 354 GElf_Ehdr ehdr; 355 char sympltname[1024]; 356 Elf *elf; 357 int nr = 0, symidx, err = 0; 358 359 if (!ss->dynsym) 360 return 0; 361 362 elf = ss->elf; 363 ehdr = ss->ehdr; 364 365 scn_dynsym = ss->dynsym; 366 shdr_dynsym = ss->dynshdr; 367 dynsym_idx = ss->dynsym_idx; 368 369 if (scn_dynsym == NULL) 370 goto out_elf_end; 371 372 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 373 ".rela.plt", NULL); 374 if (scn_plt_rel == NULL) { 375 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 376 ".rel.plt", NULL); 377 if (scn_plt_rel == NULL) 378 goto out_elf_end; 379 } 380 381 err = -1; 382 383 if (shdr_rel_plt.sh_link != dynsym_idx) 384 goto out_elf_end; 385 386 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL) 387 goto out_elf_end; 388 389 /* 390 * Fetch the relocation section to find the idxes to the GOT 391 * and the symbols in the .dynsym they refer to. 392 */ 393 reldata = elf_getdata(scn_plt_rel, NULL); 394 if (reldata == NULL) 395 goto out_elf_end; 396 397 syms = elf_getdata(scn_dynsym, NULL); 398 if (syms == NULL) 399 goto out_elf_end; 400 401 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link); 402 if (scn_symstrs == NULL) 403 goto out_elf_end; 404 405 symstrs = elf_getdata(scn_symstrs, NULL); 406 if (symstrs == NULL) 407 goto out_elf_end; 408 409 if (symstrs->d_size == 0) 410 goto out_elf_end; 411 412 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; 413 plt_offset = shdr_plt.sh_offset; 414 switch (ehdr.e_machine) { 415 case EM_ARM: 416 plt_header_size = 20; 417 plt_entry_size = 12; 418 break; 419 420 case EM_AARCH64: 421 plt_header_size = 32; 422 plt_entry_size = 16; 423 break; 424 425 case EM_SPARC: 426 plt_header_size = 48; 427 plt_entry_size = 12; 428 break; 429 430 case EM_SPARCV9: 431 plt_header_size = 128; 432 plt_entry_size = 32; 433 break; 434 435 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */ 436 plt_header_size = shdr_plt.sh_entsize; 437 plt_entry_size = shdr_plt.sh_entsize; 438 break; 439 } 440 plt_offset += plt_header_size; 441 442 if (shdr_rel_plt.sh_type == SHT_RELA) { 443 GElf_Rela pos_mem, *pos; 444 445 elf_section__for_each_rela(reldata, pos, pos_mem, idx, 446 nr_rel_entries) { 447 const char *elf_name = NULL; 448 char *demangled = NULL; 449 symidx = GELF_R_SYM(pos->r_info); 450 gelf_getsym(syms, symidx, &sym); 451 452 elf_name = elf_sym__name(&sym, symstrs); 453 demangled = demangle_sym(dso, 0, elf_name); 454 if (demangled != NULL) 455 elf_name = demangled; 456 snprintf(sympltname, sizeof(sympltname), 457 "%s@plt", elf_name); 458 free(demangled); 459 460 f = symbol__new(plt_offset, plt_entry_size, 461 STB_GLOBAL, STT_FUNC, sympltname); 462 if (!f) 463 goto out_elf_end; 464 465 plt_offset += plt_entry_size; 466 symbols__insert(&dso->symbols, f); 467 ++nr; 468 } 469 } else if (shdr_rel_plt.sh_type == SHT_REL) { 470 GElf_Rel pos_mem, *pos; 471 elf_section__for_each_rel(reldata, pos, pos_mem, idx, 472 nr_rel_entries) { 473 const char *elf_name = NULL; 474 char *demangled = NULL; 475 symidx = GELF_R_SYM(pos->r_info); 476 gelf_getsym(syms, symidx, &sym); 477 478 elf_name = elf_sym__name(&sym, symstrs); 479 demangled = demangle_sym(dso, 0, elf_name); 480 if (demangled != NULL) 481 elf_name = demangled; 482 snprintf(sympltname, sizeof(sympltname), 483 "%s@plt", elf_name); 484 free(demangled); 485 486 f = symbol__new(plt_offset, plt_entry_size, 487 STB_GLOBAL, STT_FUNC, sympltname); 488 if (!f) 489 goto out_elf_end; 490 491 plt_offset += plt_entry_size; 492 symbols__insert(&dso->symbols, f); 493 ++nr; 494 } 495 } 496 497 err = 0; 498 out_elf_end: 499 if (err == 0) 500 return nr; 501 pr_debug("%s: problems reading %s PLT info.\n", 502 __func__, dso->long_name); 503 return 0; 504 } 505 506 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 507 { 508 return demangle_sym(dso, kmodule, elf_name); 509 } 510 511 /* 512 * Align offset to 4 bytes as needed for note name and descriptor data. 513 */ 514 #define NOTE_ALIGN(n) (((n) + 3) & -4U) 515 516 static int elf_read_build_id(Elf *elf, void *bf, size_t size) 517 { 518 int err = -1; 519 GElf_Ehdr ehdr; 520 GElf_Shdr shdr; 521 Elf_Data *data; 522 Elf_Scn *sec; 523 Elf_Kind ek; 524 void *ptr; 525 526 if (size < BUILD_ID_SIZE) 527 goto out; 528 529 ek = elf_kind(elf); 530 if (ek != ELF_K_ELF) 531 goto out; 532 533 if (gelf_getehdr(elf, &ehdr) == NULL) { 534 pr_err("%s: cannot get elf header.\n", __func__); 535 goto out; 536 } 537 538 /* 539 * Check following sections for notes: 540 * '.note.gnu.build-id' 541 * '.notes' 542 * '.note' (VDSO specific) 543 */ 544 do { 545 sec = elf_section_by_name(elf, &ehdr, &shdr, 546 ".note.gnu.build-id", NULL); 547 if (sec) 548 break; 549 550 sec = elf_section_by_name(elf, &ehdr, &shdr, 551 ".notes", NULL); 552 if (sec) 553 break; 554 555 sec = elf_section_by_name(elf, &ehdr, &shdr, 556 ".note", NULL); 557 if (sec) 558 break; 559 560 return err; 561 562 } while (0); 563 564 data = elf_getdata(sec, NULL); 565 if (data == NULL) 566 goto out; 567 568 ptr = data->d_buf; 569 while (ptr < (data->d_buf + data->d_size)) { 570 GElf_Nhdr *nhdr = ptr; 571 size_t namesz = NOTE_ALIGN(nhdr->n_namesz), 572 descsz = NOTE_ALIGN(nhdr->n_descsz); 573 const char *name; 574 575 ptr += sizeof(*nhdr); 576 name = ptr; 577 ptr += namesz; 578 if (nhdr->n_type == NT_GNU_BUILD_ID && 579 nhdr->n_namesz == sizeof("GNU")) { 580 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 581 size_t sz = min(size, descsz); 582 memcpy(bf, ptr, sz); 583 memset(bf + sz, 0, size - sz); 584 err = descsz; 585 break; 586 } 587 } 588 ptr += descsz; 589 } 590 591 out: 592 return err; 593 } 594 595 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT 596 597 static int read_build_id(const char *filename, struct build_id *bid) 598 { 599 size_t size = sizeof(bid->data); 600 int err = -1; 601 bfd *abfd; 602 603 abfd = bfd_openr(filename, NULL); 604 if (!abfd) 605 return -1; 606 607 if (!bfd_check_format(abfd, bfd_object)) { 608 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 609 goto out_close; 610 } 611 612 if (!abfd->build_id || abfd->build_id->size > size) 613 goto out_close; 614 615 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size); 616 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size); 617 err = bid->size = abfd->build_id->size; 618 619 out_close: 620 bfd_close(abfd); 621 return err; 622 } 623 624 #else // HAVE_LIBBFD_BUILDID_SUPPORT 625 626 static int read_build_id(const char *filename, struct build_id *bid) 627 { 628 size_t size = sizeof(bid->data); 629 int fd, err = -1; 630 Elf *elf; 631 632 if (size < BUILD_ID_SIZE) 633 goto out; 634 635 fd = open(filename, O_RDONLY); 636 if (fd < 0) 637 goto out; 638 639 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 640 if (elf == NULL) { 641 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 642 goto out_close; 643 } 644 645 err = elf_read_build_id(elf, bid->data, size); 646 if (err > 0) 647 bid->size = err; 648 649 elf_end(elf); 650 out_close: 651 close(fd); 652 out: 653 return err; 654 } 655 656 #endif // HAVE_LIBBFD_BUILDID_SUPPORT 657 658 int filename__read_build_id(const char *filename, struct build_id *bid) 659 { 660 struct kmod_path m = { .name = NULL, }; 661 char path[PATH_MAX]; 662 int err; 663 664 if (!filename) 665 return -EFAULT; 666 667 err = kmod_path__parse(&m, filename); 668 if (err) 669 return -1; 670 671 if (m.comp) { 672 int error = 0, fd; 673 674 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error); 675 if (fd < 0) { 676 pr_debug("Failed to decompress (error %d) %s\n", 677 error, filename); 678 return -1; 679 } 680 close(fd); 681 filename = path; 682 } 683 684 err = read_build_id(filename, bid); 685 686 if (m.comp) 687 unlink(filename); 688 return err; 689 } 690 691 int sysfs__read_build_id(const char *filename, struct build_id *bid) 692 { 693 size_t size = sizeof(bid->data); 694 int fd, err = -1; 695 696 fd = open(filename, O_RDONLY); 697 if (fd < 0) 698 goto out; 699 700 while (1) { 701 char bf[BUFSIZ]; 702 GElf_Nhdr nhdr; 703 size_t namesz, descsz; 704 705 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) 706 break; 707 708 namesz = NOTE_ALIGN(nhdr.n_namesz); 709 descsz = NOTE_ALIGN(nhdr.n_descsz); 710 if (nhdr.n_type == NT_GNU_BUILD_ID && 711 nhdr.n_namesz == sizeof("GNU")) { 712 if (read(fd, bf, namesz) != (ssize_t)namesz) 713 break; 714 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { 715 size_t sz = min(descsz, size); 716 if (read(fd, bid->data, sz) == (ssize_t)sz) { 717 memset(bid->data + sz, 0, size - sz); 718 bid->size = sz; 719 err = 0; 720 break; 721 } 722 } else if (read(fd, bf, descsz) != (ssize_t)descsz) 723 break; 724 } else { 725 int n = namesz + descsz; 726 727 if (n > (int)sizeof(bf)) { 728 n = sizeof(bf); 729 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", 730 __func__, filename, nhdr.n_namesz, nhdr.n_descsz); 731 } 732 if (read(fd, bf, n) != n) 733 break; 734 } 735 } 736 close(fd); 737 out: 738 return err; 739 } 740 741 #ifdef HAVE_LIBBFD_SUPPORT 742 743 int filename__read_debuglink(const char *filename, char *debuglink, 744 size_t size) 745 { 746 int err = -1; 747 asection *section; 748 bfd *abfd; 749 750 abfd = bfd_openr(filename, NULL); 751 if (!abfd) 752 return -1; 753 754 if (!bfd_check_format(abfd, bfd_object)) { 755 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 756 goto out_close; 757 } 758 759 section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); 760 if (!section) 761 goto out_close; 762 763 if (section->size > size) 764 goto out_close; 765 766 if (!bfd_get_section_contents(abfd, section, debuglink, 0, 767 section->size)) 768 goto out_close; 769 770 err = 0; 771 772 out_close: 773 bfd_close(abfd); 774 return err; 775 } 776 777 #else 778 779 int filename__read_debuglink(const char *filename, char *debuglink, 780 size_t size) 781 { 782 int fd, err = -1; 783 Elf *elf; 784 GElf_Ehdr ehdr; 785 GElf_Shdr shdr; 786 Elf_Data *data; 787 Elf_Scn *sec; 788 Elf_Kind ek; 789 790 fd = open(filename, O_RDONLY); 791 if (fd < 0) 792 goto out; 793 794 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 795 if (elf == NULL) { 796 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 797 goto out_close; 798 } 799 800 ek = elf_kind(elf); 801 if (ek != ELF_K_ELF) 802 goto out_elf_end; 803 804 if (gelf_getehdr(elf, &ehdr) == NULL) { 805 pr_err("%s: cannot get elf header.\n", __func__); 806 goto out_elf_end; 807 } 808 809 sec = elf_section_by_name(elf, &ehdr, &shdr, 810 ".gnu_debuglink", NULL); 811 if (sec == NULL) 812 goto out_elf_end; 813 814 data = elf_getdata(sec, NULL); 815 if (data == NULL) 816 goto out_elf_end; 817 818 /* the start of this section is a zero-terminated string */ 819 strncpy(debuglink, data->d_buf, size); 820 821 err = 0; 822 823 out_elf_end: 824 elf_end(elf); 825 out_close: 826 close(fd); 827 out: 828 return err; 829 } 830 831 #endif 832 833 static int dso__swap_init(struct dso *dso, unsigned char eidata) 834 { 835 static unsigned int const endian = 1; 836 837 dso->needs_swap = DSO_SWAP__NO; 838 839 switch (eidata) { 840 case ELFDATA2LSB: 841 /* We are big endian, DSO is little endian. */ 842 if (*(unsigned char const *)&endian != 1) 843 dso->needs_swap = DSO_SWAP__YES; 844 break; 845 846 case ELFDATA2MSB: 847 /* We are little endian, DSO is big endian. */ 848 if (*(unsigned char const *)&endian != 0) 849 dso->needs_swap = DSO_SWAP__YES; 850 break; 851 852 default: 853 pr_err("unrecognized DSO data encoding %d\n", eidata); 854 return -EINVAL; 855 } 856 857 return 0; 858 } 859 860 bool symsrc__possibly_runtime(struct symsrc *ss) 861 { 862 return ss->dynsym || ss->opdsec; 863 } 864 865 bool symsrc__has_symtab(struct symsrc *ss) 866 { 867 return ss->symtab != NULL; 868 } 869 870 void symsrc__destroy(struct symsrc *ss) 871 { 872 zfree(&ss->name); 873 elf_end(ss->elf); 874 close(ss->fd); 875 } 876 877 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) 878 { 879 /* 880 * Usually vmlinux is an ELF file with type ET_EXEC for most 881 * architectures; except Arm64 kernel is linked with option 882 * '-share', so need to check type ET_DYN. 883 */ 884 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL || 885 ehdr.e_type == ET_DYN; 886 } 887 888 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 889 enum dso_binary_type type) 890 { 891 GElf_Ehdr ehdr; 892 Elf *elf; 893 int fd; 894 895 if (dso__needs_decompress(dso)) { 896 fd = dso__decompress_kmodule_fd(dso, name); 897 if (fd < 0) 898 return -1; 899 900 type = dso->symtab_type; 901 } else { 902 fd = open(name, O_RDONLY); 903 if (fd < 0) { 904 dso->load_errno = errno; 905 return -1; 906 } 907 } 908 909 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 910 if (elf == NULL) { 911 pr_debug("%s: cannot read %s ELF file.\n", __func__, name); 912 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 913 goto out_close; 914 } 915 916 if (gelf_getehdr(elf, &ehdr) == NULL) { 917 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 918 pr_debug("%s: cannot get elf header.\n", __func__); 919 goto out_elf_end; 920 } 921 922 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { 923 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR; 924 goto out_elf_end; 925 } 926 927 /* Always reject images with a mismatched build-id: */ 928 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) { 929 u8 build_id[BUILD_ID_SIZE]; 930 struct build_id bid; 931 int size; 932 933 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE); 934 if (size <= 0) { 935 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; 936 goto out_elf_end; 937 } 938 939 build_id__init(&bid, build_id, size); 940 if (!dso__build_id_equal(dso, &bid)) { 941 pr_debug("%s: build id mismatch for %s.\n", __func__, name); 942 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; 943 goto out_elf_end; 944 } 945 } 946 947 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 948 949 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", 950 NULL); 951 if (ss->symshdr.sh_type != SHT_SYMTAB) 952 ss->symtab = NULL; 953 954 ss->dynsym_idx = 0; 955 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", 956 &ss->dynsym_idx); 957 if (ss->dynshdr.sh_type != SHT_DYNSYM) 958 ss->dynsym = NULL; 959 960 ss->opdidx = 0; 961 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", 962 &ss->opdidx); 963 if (ss->opdshdr.sh_type != SHT_PROGBITS) 964 ss->opdsec = NULL; 965 966 if (dso->kernel == DSO_SPACE__USER) 967 ss->adjust_symbols = true; 968 else 969 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); 970 971 ss->name = strdup(name); 972 if (!ss->name) { 973 dso->load_errno = errno; 974 goto out_elf_end; 975 } 976 977 ss->elf = elf; 978 ss->fd = fd; 979 ss->ehdr = ehdr; 980 ss->type = type; 981 982 return 0; 983 984 out_elf_end: 985 elf_end(elf); 986 out_close: 987 close(fd); 988 return -1; 989 } 990 991 /** 992 * ref_reloc_sym_not_found - has kernel relocation symbol been found. 993 * @kmap: kernel maps and relocation reference symbol 994 * 995 * This function returns %true if we are dealing with the kernel maps and the 996 * relocation reference symbol has not yet been found. Otherwise %false is 997 * returned. 998 */ 999 static bool ref_reloc_sym_not_found(struct kmap *kmap) 1000 { 1001 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && 1002 !kmap->ref_reloc_sym->unrelocated_addr; 1003 } 1004 1005 /** 1006 * ref_reloc - kernel relocation offset. 1007 * @kmap: kernel maps and relocation reference symbol 1008 * 1009 * This function returns the offset of kernel addresses as determined by using 1010 * the relocation reference symbol i.e. if the kernel has not been relocated 1011 * then the return value is zero. 1012 */ 1013 static u64 ref_reloc(struct kmap *kmap) 1014 { 1015 if (kmap && kmap->ref_reloc_sym && 1016 kmap->ref_reloc_sym->unrelocated_addr) 1017 return kmap->ref_reloc_sym->addr - 1018 kmap->ref_reloc_sym->unrelocated_addr; 1019 return 0; 1020 } 1021 1022 void __weak arch__sym_update(struct symbol *s __maybe_unused, 1023 GElf_Sym *sym __maybe_unused) { } 1024 1025 static int dso__process_kernel_symbol(struct dso *dso, struct map *map, 1026 GElf_Sym *sym, GElf_Shdr *shdr, 1027 struct maps *kmaps, struct kmap *kmap, 1028 struct dso **curr_dsop, struct map **curr_mapp, 1029 const char *section_name, 1030 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) 1031 { 1032 struct dso *curr_dso = *curr_dsop; 1033 struct map *curr_map; 1034 char dso_name[PATH_MAX]; 1035 1036 /* Adjust symbol to map to file offset */ 1037 if (adjust_kernel_syms) 1038 sym->st_value -= shdr->sh_addr - shdr->sh_offset; 1039 1040 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0) 1041 return 0; 1042 1043 if (strcmp(section_name, ".text") == 0) { 1044 /* 1045 * The initial kernel mapping is based on 1046 * kallsyms and identity maps. Overwrite it to 1047 * map to the kernel dso. 1048 */ 1049 if (*remap_kernel && dso->kernel && !kmodule) { 1050 *remap_kernel = false; 1051 map->start = shdr->sh_addr + ref_reloc(kmap); 1052 map->end = map->start + shdr->sh_size; 1053 map->pgoff = shdr->sh_offset; 1054 map->map_ip = map__map_ip; 1055 map->unmap_ip = map__unmap_ip; 1056 /* Ensure maps are correctly ordered */ 1057 if (kmaps) { 1058 map__get(map); 1059 maps__remove(kmaps, map); 1060 maps__insert(kmaps, map); 1061 map__put(map); 1062 } 1063 } 1064 1065 /* 1066 * The initial module mapping is based on 1067 * /proc/modules mapped to offset zero. 1068 * Overwrite it to map to the module dso. 1069 */ 1070 if (*remap_kernel && kmodule) { 1071 *remap_kernel = false; 1072 map->pgoff = shdr->sh_offset; 1073 } 1074 1075 *curr_mapp = map; 1076 *curr_dsop = dso; 1077 return 0; 1078 } 1079 1080 if (!kmap) 1081 return 0; 1082 1083 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); 1084 1085 curr_map = maps__find_by_name(kmaps, dso_name); 1086 if (curr_map == NULL) { 1087 u64 start = sym->st_value; 1088 1089 if (kmodule) 1090 start += map->start + shdr->sh_offset; 1091 1092 curr_dso = dso__new(dso_name); 1093 if (curr_dso == NULL) 1094 return -1; 1095 curr_dso->kernel = dso->kernel; 1096 curr_dso->long_name = dso->long_name; 1097 curr_dso->long_name_len = dso->long_name_len; 1098 curr_map = map__new2(start, curr_dso); 1099 dso__put(curr_dso); 1100 if (curr_map == NULL) 1101 return -1; 1102 1103 if (curr_dso->kernel) 1104 map__kmap(curr_map)->kmaps = kmaps; 1105 1106 if (adjust_kernel_syms) { 1107 curr_map->start = shdr->sh_addr + ref_reloc(kmap); 1108 curr_map->end = curr_map->start + shdr->sh_size; 1109 curr_map->pgoff = shdr->sh_offset; 1110 } else { 1111 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; 1112 } 1113 curr_dso->symtab_type = dso->symtab_type; 1114 maps__insert(kmaps, curr_map); 1115 /* 1116 * Add it before we drop the reference to curr_map, i.e. while 1117 * we still are sure to have a reference to this DSO via 1118 * *curr_map->dso. 1119 */ 1120 dsos__add(&kmaps->machine->dsos, curr_dso); 1121 /* kmaps already got it */ 1122 map__put(curr_map); 1123 dso__set_loaded(curr_dso); 1124 *curr_mapp = curr_map; 1125 *curr_dsop = curr_dso; 1126 } else 1127 *curr_dsop = curr_map->dso; 1128 1129 return 0; 1130 } 1131 1132 static int 1133 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1134 struct symsrc *runtime_ss, int kmodule, int dynsym) 1135 { 1136 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; 1137 struct maps *kmaps = kmap ? map__kmaps(map) : NULL; 1138 struct map *curr_map = map; 1139 struct dso *curr_dso = dso; 1140 Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym; 1141 uint32_t nr_syms; 1142 int err = -1; 1143 uint32_t idx; 1144 GElf_Ehdr ehdr; 1145 GElf_Shdr shdr; 1146 GElf_Shdr tshdr; 1147 Elf_Data *syms, *opddata = NULL; 1148 GElf_Sym sym; 1149 Elf_Scn *sec, *sec_strndx; 1150 Elf *elf; 1151 int nr = 0; 1152 bool remap_kernel = false, adjust_kernel_syms = false; 1153 1154 if (kmap && !kmaps) 1155 return -1; 1156 1157 elf = syms_ss->elf; 1158 ehdr = syms_ss->ehdr; 1159 if (dynsym) { 1160 sec = syms_ss->dynsym; 1161 shdr = syms_ss->dynshdr; 1162 } else { 1163 sec = syms_ss->symtab; 1164 shdr = syms_ss->symshdr; 1165 } 1166 1167 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, 1168 ".text", NULL)) 1169 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; 1170 1171 if (runtime_ss->opdsec) 1172 opddata = elf_rawdata(runtime_ss->opdsec, NULL); 1173 1174 syms = elf_getdata(sec, NULL); 1175 if (syms == NULL) 1176 goto out_elf_end; 1177 1178 sec = elf_getscn(elf, shdr.sh_link); 1179 if (sec == NULL) 1180 goto out_elf_end; 1181 1182 symstrs = elf_getdata(sec, NULL); 1183 if (symstrs == NULL) 1184 goto out_elf_end; 1185 1186 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); 1187 if (sec_strndx == NULL) 1188 goto out_elf_end; 1189 1190 secstrs_run = elf_getdata(sec_strndx, NULL); 1191 if (secstrs_run == NULL) 1192 goto out_elf_end; 1193 1194 sec_strndx = elf_getscn(elf, ehdr.e_shstrndx); 1195 if (sec_strndx == NULL) 1196 goto out_elf_end; 1197 1198 secstrs_sym = elf_getdata(sec_strndx, NULL); 1199 if (secstrs_sym == NULL) 1200 goto out_elf_end; 1201 1202 nr_syms = shdr.sh_size / shdr.sh_entsize; 1203 1204 memset(&sym, 0, sizeof(sym)); 1205 1206 /* 1207 * The kernel relocation symbol is needed in advance in order to adjust 1208 * kernel maps correctly. 1209 */ 1210 if (ref_reloc_sym_not_found(kmap)) { 1211 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1212 const char *elf_name = elf_sym__name(&sym, symstrs); 1213 1214 if (strcmp(elf_name, kmap->ref_reloc_sym->name)) 1215 continue; 1216 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; 1217 map->reloc = kmap->ref_reloc_sym->addr - 1218 kmap->ref_reloc_sym->unrelocated_addr; 1219 break; 1220 } 1221 } 1222 1223 /* 1224 * Handle any relocation of vdso necessary because older kernels 1225 * attempted to prelink vdso to its virtual address. 1226 */ 1227 if (dso__is_vdso(dso)) 1228 map->reloc = map->start - dso->text_offset; 1229 1230 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); 1231 /* 1232 * Initial kernel and module mappings do not map to the dso. 1233 * Flag the fixups. 1234 */ 1235 if (dso->kernel) { 1236 remap_kernel = true; 1237 adjust_kernel_syms = dso->adjust_symbols; 1238 } 1239 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1240 struct symbol *f; 1241 const char *elf_name = elf_sym__name(&sym, symstrs); 1242 char *demangled = NULL; 1243 int is_label = elf_sym__is_label(&sym); 1244 const char *section_name; 1245 bool used_opd = false; 1246 1247 if (!is_label && !elf_sym__filter(&sym)) 1248 continue; 1249 1250 /* Reject ARM ELF "mapping symbols": these aren't unique and 1251 * don't identify functions, so will confuse the profile 1252 * output: */ 1253 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { 1254 if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) 1255 && (elf_name[2] == '\0' || elf_name[2] == '.')) 1256 continue; 1257 } 1258 1259 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { 1260 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; 1261 u64 *opd = opddata->d_buf + offset; 1262 sym.st_value = DSO__SWAP(dso, u64, *opd); 1263 sym.st_shndx = elf_addr_to_index(runtime_ss->elf, 1264 sym.st_value); 1265 used_opd = true; 1266 } 1267 1268 /* 1269 * When loading symbols in a data mapping, ABS symbols (which 1270 * has a value of SHN_ABS in its st_shndx) failed at 1271 * elf_getscn(). And it marks the loading as a failure so 1272 * already loaded symbols cannot be fixed up. 1273 * 1274 * I'm not sure what should be done. Just ignore them for now. 1275 * - Namhyung Kim 1276 */ 1277 if (sym.st_shndx == SHN_ABS) 1278 continue; 1279 1280 sec = elf_getscn(syms_ss->elf, sym.st_shndx); 1281 if (!sec) 1282 goto out_elf_end; 1283 1284 gelf_getshdr(sec, &shdr); 1285 1286 /* 1287 * If the attribute bit SHF_ALLOC is not set, the section 1288 * doesn't occupy memory during process execution. 1289 * E.g. ".gnu.warning.*" section is used by linker to generate 1290 * warnings when calling deprecated functions, the symbols in 1291 * the section aren't loaded to memory during process execution, 1292 * so skip them. 1293 */ 1294 if (!(shdr.sh_flags & SHF_ALLOC)) 1295 continue; 1296 1297 secstrs = secstrs_sym; 1298 1299 /* 1300 * We have to fallback to runtime when syms' section header has 1301 * NOBITS set. NOBITS results in file offset (sh_offset) not 1302 * being incremented. So sh_offset used below has different 1303 * values for syms (invalid) and runtime (valid). 1304 */ 1305 if (shdr.sh_type == SHT_NOBITS) { 1306 sec = elf_getscn(runtime_ss->elf, sym.st_shndx); 1307 if (!sec) 1308 goto out_elf_end; 1309 1310 gelf_getshdr(sec, &shdr); 1311 secstrs = secstrs_run; 1312 } 1313 1314 if (is_label && !elf_sec__filter(&shdr, secstrs)) 1315 continue; 1316 1317 section_name = elf_sec__name(&shdr, secstrs); 1318 1319 /* On ARM, symbols for thumb functions have 1 added to 1320 * the symbol address as a flag - remove it */ 1321 if ((ehdr.e_machine == EM_ARM) && 1322 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && 1323 (sym.st_value & 1)) 1324 --sym.st_value; 1325 1326 if (dso->kernel) { 1327 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, 1328 section_name, adjust_kernel_syms, kmodule, &remap_kernel)) 1329 goto out_elf_end; 1330 } else if ((used_opd && runtime_ss->adjust_symbols) || 1331 (!used_opd && syms_ss->adjust_symbols)) { 1332 GElf_Phdr phdr; 1333 1334 if (elf_read_program_header(runtime_ss->elf, 1335 (u64)sym.st_value, &phdr)) { 1336 pr_debug4("%s: failed to find program header for " 1337 "symbol: %s st_value: %#" PRIx64 "\n", 1338 __func__, elf_name, (u64)sym.st_value); 1339 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1340 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", 1341 __func__, (u64)sym.st_value, (u64)shdr.sh_addr, 1342 (u64)shdr.sh_offset); 1343 /* 1344 * Fail to find program header, let's rollback 1345 * to use shdr.sh_addr and shdr.sh_offset to 1346 * calibrate symbol's file address, though this 1347 * is not necessary for normal C ELF file, we 1348 * still need to handle java JIT symbols in this 1349 * case. 1350 */ 1351 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 1352 } else { 1353 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1354 "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n", 1355 __func__, (u64)sym.st_value, (u64)phdr.p_vaddr, 1356 (u64)phdr.p_offset); 1357 sym.st_value -= phdr.p_vaddr - phdr.p_offset; 1358 } 1359 } 1360 1361 demangled = demangle_sym(dso, kmodule, elf_name); 1362 if (demangled != NULL) 1363 elf_name = demangled; 1364 1365 f = symbol__new(sym.st_value, sym.st_size, 1366 GELF_ST_BIND(sym.st_info), 1367 GELF_ST_TYPE(sym.st_info), elf_name); 1368 free(demangled); 1369 if (!f) 1370 goto out_elf_end; 1371 1372 arch__sym_update(f, &sym); 1373 1374 __symbols__insert(&curr_dso->symbols, f, dso->kernel); 1375 nr++; 1376 } 1377 1378 /* 1379 * For misannotated, zeroed, ASM function sizes. 1380 */ 1381 if (nr > 0) { 1382 symbols__fixup_end(&dso->symbols, false); 1383 symbols__fixup_duplicate(&dso->symbols); 1384 if (kmap) { 1385 /* 1386 * We need to fixup this here too because we create new 1387 * maps here, for things like vsyscall sections. 1388 */ 1389 maps__fixup_end(kmaps); 1390 } 1391 } 1392 err = nr; 1393 out_elf_end: 1394 return err; 1395 } 1396 1397 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1398 struct symsrc *runtime_ss, int kmodule) 1399 { 1400 int nr = 0; 1401 int err = -1; 1402 1403 dso->symtab_type = syms_ss->type; 1404 dso->is_64_bit = syms_ss->is_64_bit; 1405 dso->rel = syms_ss->ehdr.e_type == ET_REL; 1406 1407 /* 1408 * Modules may already have symbols from kallsyms, but those symbols 1409 * have the wrong values for the dso maps, so remove them. 1410 */ 1411 if (kmodule && syms_ss->symtab) 1412 symbols__delete(&dso->symbols); 1413 1414 if (!syms_ss->symtab) { 1415 /* 1416 * If the vmlinux is stripped, fail so we will fall back 1417 * to using kallsyms. The vmlinux runtime symbols aren't 1418 * of much use. 1419 */ 1420 if (dso->kernel) 1421 return err; 1422 } else { 1423 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, 1424 kmodule, 0); 1425 if (err < 0) 1426 return err; 1427 nr = err; 1428 } 1429 1430 if (syms_ss->dynsym) { 1431 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, 1432 kmodule, 1); 1433 if (err < 0) 1434 return err; 1435 err += nr; 1436 } 1437 1438 return err; 1439 } 1440 1441 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) 1442 { 1443 GElf_Phdr phdr; 1444 size_t i, phdrnum; 1445 int err; 1446 u64 sz; 1447 1448 if (elf_getphdrnum(elf, &phdrnum)) 1449 return -1; 1450 1451 for (i = 0; i < phdrnum; i++) { 1452 if (gelf_getphdr(elf, i, &phdr) == NULL) 1453 return -1; 1454 if (phdr.p_type != PT_LOAD) 1455 continue; 1456 if (exe) { 1457 if (!(phdr.p_flags & PF_X)) 1458 continue; 1459 } else { 1460 if (!(phdr.p_flags & PF_R)) 1461 continue; 1462 } 1463 sz = min(phdr.p_memsz, phdr.p_filesz); 1464 if (!sz) 1465 continue; 1466 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); 1467 if (err) 1468 return err; 1469 } 1470 return 0; 1471 } 1472 1473 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, 1474 bool *is_64_bit) 1475 { 1476 int err; 1477 Elf *elf; 1478 1479 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1480 if (elf == NULL) 1481 return -1; 1482 1483 if (is_64_bit) 1484 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1485 1486 err = elf_read_maps(elf, exe, mapfn, data); 1487 1488 elf_end(elf); 1489 return err; 1490 } 1491 1492 enum dso_type dso__type_fd(int fd) 1493 { 1494 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 1495 GElf_Ehdr ehdr; 1496 Elf_Kind ek; 1497 Elf *elf; 1498 1499 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1500 if (elf == NULL) 1501 goto out; 1502 1503 ek = elf_kind(elf); 1504 if (ek != ELF_K_ELF) 1505 goto out_end; 1506 1507 if (gelf_getclass(elf) == ELFCLASS64) { 1508 dso_type = DSO__TYPE_64BIT; 1509 goto out_end; 1510 } 1511 1512 if (gelf_getehdr(elf, &ehdr) == NULL) 1513 goto out_end; 1514 1515 if (ehdr.e_machine == EM_X86_64) 1516 dso_type = DSO__TYPE_X32BIT; 1517 else 1518 dso_type = DSO__TYPE_32BIT; 1519 out_end: 1520 elf_end(elf); 1521 out: 1522 return dso_type; 1523 } 1524 1525 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) 1526 { 1527 ssize_t r; 1528 size_t n; 1529 int err = -1; 1530 char *buf = malloc(page_size); 1531 1532 if (buf == NULL) 1533 return -1; 1534 1535 if (lseek(to, to_offs, SEEK_SET) != to_offs) 1536 goto out; 1537 1538 if (lseek(from, from_offs, SEEK_SET) != from_offs) 1539 goto out; 1540 1541 while (len) { 1542 n = page_size; 1543 if (len < n) 1544 n = len; 1545 /* Use read because mmap won't work on proc files */ 1546 r = read(from, buf, n); 1547 if (r < 0) 1548 goto out; 1549 if (!r) 1550 break; 1551 n = r; 1552 r = write(to, buf, n); 1553 if (r < 0) 1554 goto out; 1555 if ((size_t)r != n) 1556 goto out; 1557 len -= n; 1558 } 1559 1560 err = 0; 1561 out: 1562 free(buf); 1563 return err; 1564 } 1565 1566 struct kcore { 1567 int fd; 1568 int elfclass; 1569 Elf *elf; 1570 GElf_Ehdr ehdr; 1571 }; 1572 1573 static int kcore__open(struct kcore *kcore, const char *filename) 1574 { 1575 GElf_Ehdr *ehdr; 1576 1577 kcore->fd = open(filename, O_RDONLY); 1578 if (kcore->fd == -1) 1579 return -1; 1580 1581 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); 1582 if (!kcore->elf) 1583 goto out_close; 1584 1585 kcore->elfclass = gelf_getclass(kcore->elf); 1586 if (kcore->elfclass == ELFCLASSNONE) 1587 goto out_end; 1588 1589 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); 1590 if (!ehdr) 1591 goto out_end; 1592 1593 return 0; 1594 1595 out_end: 1596 elf_end(kcore->elf); 1597 out_close: 1598 close(kcore->fd); 1599 return -1; 1600 } 1601 1602 static int kcore__init(struct kcore *kcore, char *filename, int elfclass, 1603 bool temp) 1604 { 1605 kcore->elfclass = elfclass; 1606 1607 if (temp) 1608 kcore->fd = mkstemp(filename); 1609 else 1610 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); 1611 if (kcore->fd == -1) 1612 return -1; 1613 1614 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); 1615 if (!kcore->elf) 1616 goto out_close; 1617 1618 if (!gelf_newehdr(kcore->elf, elfclass)) 1619 goto out_end; 1620 1621 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); 1622 1623 return 0; 1624 1625 out_end: 1626 elf_end(kcore->elf); 1627 out_close: 1628 close(kcore->fd); 1629 unlink(filename); 1630 return -1; 1631 } 1632 1633 static void kcore__close(struct kcore *kcore) 1634 { 1635 elf_end(kcore->elf); 1636 close(kcore->fd); 1637 } 1638 1639 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) 1640 { 1641 GElf_Ehdr *ehdr = &to->ehdr; 1642 GElf_Ehdr *kehdr = &from->ehdr; 1643 1644 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); 1645 ehdr->e_type = kehdr->e_type; 1646 ehdr->e_machine = kehdr->e_machine; 1647 ehdr->e_version = kehdr->e_version; 1648 ehdr->e_entry = 0; 1649 ehdr->e_shoff = 0; 1650 ehdr->e_flags = kehdr->e_flags; 1651 ehdr->e_phnum = count; 1652 ehdr->e_shentsize = 0; 1653 ehdr->e_shnum = 0; 1654 ehdr->e_shstrndx = 0; 1655 1656 if (from->elfclass == ELFCLASS32) { 1657 ehdr->e_phoff = sizeof(Elf32_Ehdr); 1658 ehdr->e_ehsize = sizeof(Elf32_Ehdr); 1659 ehdr->e_phentsize = sizeof(Elf32_Phdr); 1660 } else { 1661 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1662 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1663 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1664 } 1665 1666 if (!gelf_update_ehdr(to->elf, ehdr)) 1667 return -1; 1668 1669 if (!gelf_newphdr(to->elf, count)) 1670 return -1; 1671 1672 return 0; 1673 } 1674 1675 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, 1676 u64 addr, u64 len) 1677 { 1678 GElf_Phdr phdr = { 1679 .p_type = PT_LOAD, 1680 .p_flags = PF_R | PF_W | PF_X, 1681 .p_offset = offset, 1682 .p_vaddr = addr, 1683 .p_paddr = 0, 1684 .p_filesz = len, 1685 .p_memsz = len, 1686 .p_align = page_size, 1687 }; 1688 1689 if (!gelf_update_phdr(kcore->elf, idx, &phdr)) 1690 return -1; 1691 1692 return 0; 1693 } 1694 1695 static off_t kcore__write(struct kcore *kcore) 1696 { 1697 return elf_update(kcore->elf, ELF_C_WRITE); 1698 } 1699 1700 struct phdr_data { 1701 off_t offset; 1702 off_t rel; 1703 u64 addr; 1704 u64 len; 1705 struct list_head node; 1706 struct phdr_data *remaps; 1707 }; 1708 1709 struct sym_data { 1710 u64 addr; 1711 struct list_head node; 1712 }; 1713 1714 struct kcore_copy_info { 1715 u64 stext; 1716 u64 etext; 1717 u64 first_symbol; 1718 u64 last_symbol; 1719 u64 first_module; 1720 u64 first_module_symbol; 1721 u64 last_module_symbol; 1722 size_t phnum; 1723 struct list_head phdrs; 1724 struct list_head syms; 1725 }; 1726 1727 #define kcore_copy__for_each_phdr(k, p) \ 1728 list_for_each_entry((p), &(k)->phdrs, node) 1729 1730 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset) 1731 { 1732 struct phdr_data *p = zalloc(sizeof(*p)); 1733 1734 if (p) { 1735 p->addr = addr; 1736 p->len = len; 1737 p->offset = offset; 1738 } 1739 1740 return p; 1741 } 1742 1743 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci, 1744 u64 addr, u64 len, 1745 off_t offset) 1746 { 1747 struct phdr_data *p = phdr_data__new(addr, len, offset); 1748 1749 if (p) 1750 list_add_tail(&p->node, &kci->phdrs); 1751 1752 return p; 1753 } 1754 1755 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci) 1756 { 1757 struct phdr_data *p, *tmp; 1758 1759 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) { 1760 list_del_init(&p->node); 1761 free(p); 1762 } 1763 } 1764 1765 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci, 1766 u64 addr) 1767 { 1768 struct sym_data *s = zalloc(sizeof(*s)); 1769 1770 if (s) { 1771 s->addr = addr; 1772 list_add_tail(&s->node, &kci->syms); 1773 } 1774 1775 return s; 1776 } 1777 1778 static void kcore_copy__free_syms(struct kcore_copy_info *kci) 1779 { 1780 struct sym_data *s, *tmp; 1781 1782 list_for_each_entry_safe(s, tmp, &kci->syms, node) { 1783 list_del_init(&s->node); 1784 free(s); 1785 } 1786 } 1787 1788 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 1789 u64 start) 1790 { 1791 struct kcore_copy_info *kci = arg; 1792 1793 if (!kallsyms__is_function(type)) 1794 return 0; 1795 1796 if (strchr(name, '[')) { 1797 if (!kci->first_module_symbol || start < kci->first_module_symbol) 1798 kci->first_module_symbol = start; 1799 if (start > kci->last_module_symbol) 1800 kci->last_module_symbol = start; 1801 return 0; 1802 } 1803 1804 if (!kci->first_symbol || start < kci->first_symbol) 1805 kci->first_symbol = start; 1806 1807 if (!kci->last_symbol || start > kci->last_symbol) 1808 kci->last_symbol = start; 1809 1810 if (!strcmp(name, "_stext")) { 1811 kci->stext = start; 1812 return 0; 1813 } 1814 1815 if (!strcmp(name, "_etext")) { 1816 kci->etext = start; 1817 return 0; 1818 } 1819 1820 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start)) 1821 return -1; 1822 1823 return 0; 1824 } 1825 1826 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, 1827 const char *dir) 1828 { 1829 char kallsyms_filename[PATH_MAX]; 1830 1831 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); 1832 1833 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) 1834 return -1; 1835 1836 if (kallsyms__parse(kallsyms_filename, kci, 1837 kcore_copy__process_kallsyms) < 0) 1838 return -1; 1839 1840 return 0; 1841 } 1842 1843 static int kcore_copy__process_modules(void *arg, 1844 const char *name __maybe_unused, 1845 u64 start, u64 size __maybe_unused) 1846 { 1847 struct kcore_copy_info *kci = arg; 1848 1849 if (!kci->first_module || start < kci->first_module) 1850 kci->first_module = start; 1851 1852 return 0; 1853 } 1854 1855 static int kcore_copy__parse_modules(struct kcore_copy_info *kci, 1856 const char *dir) 1857 { 1858 char modules_filename[PATH_MAX]; 1859 1860 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); 1861 1862 if (symbol__restricted_filename(modules_filename, "/proc/modules")) 1863 return -1; 1864 1865 if (modules__parse(modules_filename, kci, 1866 kcore_copy__process_modules) < 0) 1867 return -1; 1868 1869 return 0; 1870 } 1871 1872 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end, 1873 u64 pgoff, u64 s, u64 e) 1874 { 1875 u64 len, offset; 1876 1877 if (s < start || s >= end) 1878 return 0; 1879 1880 offset = (s - start) + pgoff; 1881 len = e < end ? e - s : end - s; 1882 1883 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1; 1884 } 1885 1886 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) 1887 { 1888 struct kcore_copy_info *kci = data; 1889 u64 end = start + len; 1890 struct sym_data *sdat; 1891 1892 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext)) 1893 return -1; 1894 1895 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module, 1896 kci->last_module_symbol)) 1897 return -1; 1898 1899 list_for_each_entry(sdat, &kci->syms, node) { 1900 u64 s = round_down(sdat->addr, page_size); 1901 1902 if (kcore_copy__map(kci, start, end, pgoff, s, s + len)) 1903 return -1; 1904 } 1905 1906 return 0; 1907 } 1908 1909 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) 1910 { 1911 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) 1912 return -1; 1913 1914 return 0; 1915 } 1916 1917 static void kcore_copy__find_remaps(struct kcore_copy_info *kci) 1918 { 1919 struct phdr_data *p, *k = NULL; 1920 u64 kend; 1921 1922 if (!kci->stext) 1923 return; 1924 1925 /* Find phdr that corresponds to the kernel map (contains stext) */ 1926 kcore_copy__for_each_phdr(kci, p) { 1927 u64 pend = p->addr + p->len - 1; 1928 1929 if (p->addr <= kci->stext && pend >= kci->stext) { 1930 k = p; 1931 break; 1932 } 1933 } 1934 1935 if (!k) 1936 return; 1937 1938 kend = k->offset + k->len; 1939 1940 /* Find phdrs that remap the kernel */ 1941 kcore_copy__for_each_phdr(kci, p) { 1942 u64 pend = p->offset + p->len; 1943 1944 if (p == k) 1945 continue; 1946 1947 if (p->offset >= k->offset && pend <= kend) 1948 p->remaps = k; 1949 } 1950 } 1951 1952 static void kcore_copy__layout(struct kcore_copy_info *kci) 1953 { 1954 struct phdr_data *p; 1955 off_t rel = 0; 1956 1957 kcore_copy__find_remaps(kci); 1958 1959 kcore_copy__for_each_phdr(kci, p) { 1960 if (!p->remaps) { 1961 p->rel = rel; 1962 rel += p->len; 1963 } 1964 kci->phnum += 1; 1965 } 1966 1967 kcore_copy__for_each_phdr(kci, p) { 1968 struct phdr_data *k = p->remaps; 1969 1970 if (k) 1971 p->rel = p->offset - k->offset + k->rel; 1972 } 1973 } 1974 1975 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 1976 Elf *elf) 1977 { 1978 if (kcore_copy__parse_kallsyms(kci, dir)) 1979 return -1; 1980 1981 if (kcore_copy__parse_modules(kci, dir)) 1982 return -1; 1983 1984 if (kci->stext) 1985 kci->stext = round_down(kci->stext, page_size); 1986 else 1987 kci->stext = round_down(kci->first_symbol, page_size); 1988 1989 if (kci->etext) { 1990 kci->etext = round_up(kci->etext, page_size); 1991 } else if (kci->last_symbol) { 1992 kci->etext = round_up(kci->last_symbol, page_size); 1993 kci->etext += page_size; 1994 } 1995 1996 if (kci->first_module_symbol && 1997 (!kci->first_module || kci->first_module_symbol < kci->first_module)) 1998 kci->first_module = kci->first_module_symbol; 1999 2000 kci->first_module = round_down(kci->first_module, page_size); 2001 2002 if (kci->last_module_symbol) { 2003 kci->last_module_symbol = round_up(kci->last_module_symbol, 2004 page_size); 2005 kci->last_module_symbol += page_size; 2006 } 2007 2008 if (!kci->stext || !kci->etext) 2009 return -1; 2010 2011 if (kci->first_module && !kci->last_module_symbol) 2012 return -1; 2013 2014 if (kcore_copy__read_maps(kci, elf)) 2015 return -1; 2016 2017 kcore_copy__layout(kci); 2018 2019 return 0; 2020 } 2021 2022 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, 2023 const char *name) 2024 { 2025 char from_filename[PATH_MAX]; 2026 char to_filename[PATH_MAX]; 2027 2028 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 2029 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 2030 2031 return copyfile_mode(from_filename, to_filename, 0400); 2032 } 2033 2034 static int kcore_copy__unlink(const char *dir, const char *name) 2035 { 2036 char filename[PATH_MAX]; 2037 2038 scnprintf(filename, PATH_MAX, "%s/%s", dir, name); 2039 2040 return unlink(filename); 2041 } 2042 2043 static int kcore_copy__compare_fds(int from, int to) 2044 { 2045 char *buf_from; 2046 char *buf_to; 2047 ssize_t ret; 2048 size_t len; 2049 int err = -1; 2050 2051 buf_from = malloc(page_size); 2052 buf_to = malloc(page_size); 2053 if (!buf_from || !buf_to) 2054 goto out; 2055 2056 while (1) { 2057 /* Use read because mmap won't work on proc files */ 2058 ret = read(from, buf_from, page_size); 2059 if (ret < 0) 2060 goto out; 2061 2062 if (!ret) 2063 break; 2064 2065 len = ret; 2066 2067 if (readn(to, buf_to, len) != (int)len) 2068 goto out; 2069 2070 if (memcmp(buf_from, buf_to, len)) 2071 goto out; 2072 } 2073 2074 err = 0; 2075 out: 2076 free(buf_to); 2077 free(buf_from); 2078 return err; 2079 } 2080 2081 static int kcore_copy__compare_files(const char *from_filename, 2082 const char *to_filename) 2083 { 2084 int from, to, err = -1; 2085 2086 from = open(from_filename, O_RDONLY); 2087 if (from < 0) 2088 return -1; 2089 2090 to = open(to_filename, O_RDONLY); 2091 if (to < 0) 2092 goto out_close_from; 2093 2094 err = kcore_copy__compare_fds(from, to); 2095 2096 close(to); 2097 out_close_from: 2098 close(from); 2099 return err; 2100 } 2101 2102 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, 2103 const char *name) 2104 { 2105 char from_filename[PATH_MAX]; 2106 char to_filename[PATH_MAX]; 2107 2108 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 2109 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 2110 2111 return kcore_copy__compare_files(from_filename, to_filename); 2112 } 2113 2114 /** 2115 * kcore_copy - copy kallsyms, modules and kcore from one directory to another. 2116 * @from_dir: from directory 2117 * @to_dir: to directory 2118 * 2119 * This function copies kallsyms, modules and kcore files from one directory to 2120 * another. kallsyms and modules are copied entirely. Only code segments are 2121 * copied from kcore. It is assumed that two segments suffice: one for the 2122 * kernel proper and one for all the modules. The code segments are determined 2123 * from kallsyms and modules files. The kernel map starts at _stext or the 2124 * lowest function symbol, and ends at _etext or the highest function symbol. 2125 * The module map starts at the lowest module address and ends at the highest 2126 * module symbol. Start addresses are rounded down to the nearest page. End 2127 * addresses are rounded up to the nearest page. An extra page is added to the 2128 * highest kernel symbol and highest module symbol to, hopefully, encompass that 2129 * symbol too. Because it contains only code sections, the resulting kcore is 2130 * unusual. One significant peculiarity is that the mapping (start -> pgoff) 2131 * is not the same for the kernel map and the modules map. That happens because 2132 * the data is copied adjacently whereas the original kcore has gaps. Finally, 2133 * kallsyms file is compared with its copy to check that modules have not been 2134 * loaded or unloaded while the copies were taking place. 2135 * 2136 * Return: %0 on success, %-1 on failure. 2137 */ 2138 int kcore_copy(const char *from_dir, const char *to_dir) 2139 { 2140 struct kcore kcore; 2141 struct kcore extract; 2142 int idx = 0, err = -1; 2143 off_t offset, sz; 2144 struct kcore_copy_info kci = { .stext = 0, }; 2145 char kcore_filename[PATH_MAX]; 2146 char extract_filename[PATH_MAX]; 2147 struct phdr_data *p; 2148 2149 INIT_LIST_HEAD(&kci.phdrs); 2150 INIT_LIST_HEAD(&kci.syms); 2151 2152 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) 2153 return -1; 2154 2155 if (kcore_copy__copy_file(from_dir, to_dir, "modules")) 2156 goto out_unlink_kallsyms; 2157 2158 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); 2159 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); 2160 2161 if (kcore__open(&kcore, kcore_filename)) 2162 goto out_unlink_modules; 2163 2164 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) 2165 goto out_kcore_close; 2166 2167 if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) 2168 goto out_kcore_close; 2169 2170 if (kcore__copy_hdr(&kcore, &extract, kci.phnum)) 2171 goto out_extract_close; 2172 2173 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) + 2174 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT); 2175 offset = round_up(offset, page_size); 2176 2177 kcore_copy__for_each_phdr(&kci, p) { 2178 off_t offs = p->rel + offset; 2179 2180 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len)) 2181 goto out_extract_close; 2182 } 2183 2184 sz = kcore__write(&extract); 2185 if (sz < 0 || sz > offset) 2186 goto out_extract_close; 2187 2188 kcore_copy__for_each_phdr(&kci, p) { 2189 off_t offs = p->rel + offset; 2190 2191 if (p->remaps) 2192 continue; 2193 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len)) 2194 goto out_extract_close; 2195 } 2196 2197 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) 2198 goto out_extract_close; 2199 2200 err = 0; 2201 2202 out_extract_close: 2203 kcore__close(&extract); 2204 if (err) 2205 unlink(extract_filename); 2206 out_kcore_close: 2207 kcore__close(&kcore); 2208 out_unlink_modules: 2209 if (err) 2210 kcore_copy__unlink(to_dir, "modules"); 2211 out_unlink_kallsyms: 2212 if (err) 2213 kcore_copy__unlink(to_dir, "kallsyms"); 2214 2215 kcore_copy__free_phdrs(&kci); 2216 kcore_copy__free_syms(&kci); 2217 2218 return err; 2219 } 2220 2221 int kcore_extract__create(struct kcore_extract *kce) 2222 { 2223 struct kcore kcore; 2224 struct kcore extract; 2225 size_t count = 1; 2226 int idx = 0, err = -1; 2227 off_t offset = page_size, sz; 2228 2229 if (kcore__open(&kcore, kce->kcore_filename)) 2230 return -1; 2231 2232 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); 2233 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) 2234 goto out_kcore_close; 2235 2236 if (kcore__copy_hdr(&kcore, &extract, count)) 2237 goto out_extract_close; 2238 2239 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) 2240 goto out_extract_close; 2241 2242 sz = kcore__write(&extract); 2243 if (sz < 0 || sz > offset) 2244 goto out_extract_close; 2245 2246 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) 2247 goto out_extract_close; 2248 2249 err = 0; 2250 2251 out_extract_close: 2252 kcore__close(&extract); 2253 if (err) 2254 unlink(kce->extract_filename); 2255 out_kcore_close: 2256 kcore__close(&kcore); 2257 2258 return err; 2259 } 2260 2261 void kcore_extract__delete(struct kcore_extract *kce) 2262 { 2263 unlink(kce->extract_filename); 2264 } 2265 2266 #ifdef HAVE_GELF_GETNOTE_SUPPORT 2267 2268 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off) 2269 { 2270 if (!base_off) 2271 return; 2272 2273 if (tmp->bit32) 2274 tmp->addr.a32[SDT_NOTE_IDX_LOC] = 2275 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off - 2276 tmp->addr.a32[SDT_NOTE_IDX_BASE]; 2277 else 2278 tmp->addr.a64[SDT_NOTE_IDX_LOC] = 2279 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off - 2280 tmp->addr.a64[SDT_NOTE_IDX_BASE]; 2281 } 2282 2283 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr, 2284 GElf_Addr base_off) 2285 { 2286 if (!base_off) 2287 return; 2288 2289 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR]) 2290 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2291 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR]) 2292 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2293 } 2294 2295 /** 2296 * populate_sdt_note : Parse raw data and identify SDT note 2297 * @elf: elf of the opened file 2298 * @data: raw data of a section with description offset applied 2299 * @len: note description size 2300 * @type: type of the note 2301 * @sdt_notes: List to add the SDT note 2302 * 2303 * Responsible for parsing the @data in section .note.stapsdt in @elf and 2304 * if its an SDT note, it appends to @sdt_notes list. 2305 */ 2306 static int populate_sdt_note(Elf **elf, const char *data, size_t len, 2307 struct list_head *sdt_notes) 2308 { 2309 const char *provider, *name, *args; 2310 struct sdt_note *tmp = NULL; 2311 GElf_Ehdr ehdr; 2312 GElf_Shdr shdr; 2313 int ret = -EINVAL; 2314 2315 union { 2316 Elf64_Addr a64[NR_ADDR]; 2317 Elf32_Addr a32[NR_ADDR]; 2318 } buf; 2319 2320 Elf_Data dst = { 2321 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, 2322 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), 2323 .d_off = 0, .d_align = 0 2324 }; 2325 Elf_Data src = { 2326 .d_buf = (void *) data, .d_type = ELF_T_ADDR, 2327 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, 2328 .d_align = 0 2329 }; 2330 2331 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); 2332 if (!tmp) { 2333 ret = -ENOMEM; 2334 goto out_err; 2335 } 2336 2337 INIT_LIST_HEAD(&tmp->note_list); 2338 2339 if (len < dst.d_size + 3) 2340 goto out_free_note; 2341 2342 /* Translation from file representation to memory representation */ 2343 if (gelf_xlatetom(*elf, &dst, &src, 2344 elf_getident(*elf, NULL)[EI_DATA]) == NULL) { 2345 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); 2346 goto out_free_note; 2347 } 2348 2349 /* Populate the fields of sdt_note */ 2350 provider = data + dst.d_size; 2351 2352 name = (const char *)memchr(provider, '\0', data + len - provider); 2353 if (name++ == NULL) 2354 goto out_free_note; 2355 2356 tmp->provider = strdup(provider); 2357 if (!tmp->provider) { 2358 ret = -ENOMEM; 2359 goto out_free_note; 2360 } 2361 tmp->name = strdup(name); 2362 if (!tmp->name) { 2363 ret = -ENOMEM; 2364 goto out_free_prov; 2365 } 2366 2367 args = memchr(name, '\0', data + len - name); 2368 2369 /* 2370 * There is no argument if: 2371 * - We reached the end of the note; 2372 * - There is not enough room to hold a potential string; 2373 * - The argument string is empty or just contains ':'. 2374 */ 2375 if (args == NULL || data + len - args < 2 || 2376 args[1] == ':' || args[1] == '\0') 2377 tmp->args = NULL; 2378 else { 2379 tmp->args = strdup(++args); 2380 if (!tmp->args) { 2381 ret = -ENOMEM; 2382 goto out_free_name; 2383 } 2384 } 2385 2386 if (gelf_getclass(*elf) == ELFCLASS32) { 2387 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); 2388 tmp->bit32 = true; 2389 } else { 2390 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); 2391 tmp->bit32 = false; 2392 } 2393 2394 if (!gelf_getehdr(*elf, &ehdr)) { 2395 pr_debug("%s : cannot get elf header.\n", __func__); 2396 ret = -EBADF; 2397 goto out_free_args; 2398 } 2399 2400 /* Adjust the prelink effect : 2401 * Find out the .stapsdt.base section. 2402 * This scn will help us to handle prelinking (if present). 2403 * Compare the retrieved file offset of the base section with the 2404 * base address in the description of the SDT note. If its different, 2405 * then accordingly, adjust the note location. 2406 */ 2407 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) 2408 sdt_adjust_loc(tmp, shdr.sh_offset); 2409 2410 /* Adjust reference counter offset */ 2411 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) 2412 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset); 2413 2414 list_add_tail(&tmp->note_list, sdt_notes); 2415 return 0; 2416 2417 out_free_args: 2418 zfree(&tmp->args); 2419 out_free_name: 2420 zfree(&tmp->name); 2421 out_free_prov: 2422 zfree(&tmp->provider); 2423 out_free_note: 2424 free(tmp); 2425 out_err: 2426 return ret; 2427 } 2428 2429 /** 2430 * construct_sdt_notes_list : constructs a list of SDT notes 2431 * @elf : elf to look into 2432 * @sdt_notes : empty list_head 2433 * 2434 * Scans the sections in 'elf' for the section 2435 * .note.stapsdt. It, then calls populate_sdt_note to find 2436 * out the SDT events and populates the 'sdt_notes'. 2437 */ 2438 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) 2439 { 2440 GElf_Ehdr ehdr; 2441 Elf_Scn *scn = NULL; 2442 Elf_Data *data; 2443 GElf_Shdr shdr; 2444 size_t shstrndx, next; 2445 GElf_Nhdr nhdr; 2446 size_t name_off, desc_off, offset; 2447 int ret = 0; 2448 2449 if (gelf_getehdr(elf, &ehdr) == NULL) { 2450 ret = -EBADF; 2451 goto out_ret; 2452 } 2453 if (elf_getshdrstrndx(elf, &shstrndx) != 0) { 2454 ret = -EBADF; 2455 goto out_ret; 2456 } 2457 2458 /* Look for the required section */ 2459 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); 2460 if (!scn) { 2461 ret = -ENOENT; 2462 goto out_ret; 2463 } 2464 2465 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { 2466 ret = -ENOENT; 2467 goto out_ret; 2468 } 2469 2470 data = elf_getdata(scn, NULL); 2471 2472 /* Get the SDT notes */ 2473 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, 2474 &desc_off)) > 0; offset = next) { 2475 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && 2476 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, 2477 sizeof(SDT_NOTE_NAME))) { 2478 /* Check the type of the note */ 2479 if (nhdr.n_type != SDT_NOTE_TYPE) 2480 goto out_ret; 2481 2482 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), 2483 nhdr.n_descsz, sdt_notes); 2484 if (ret < 0) 2485 goto out_ret; 2486 } 2487 } 2488 if (list_empty(sdt_notes)) 2489 ret = -ENOENT; 2490 2491 out_ret: 2492 return ret; 2493 } 2494 2495 /** 2496 * get_sdt_note_list : Wrapper to construct a list of sdt notes 2497 * @head : empty list_head 2498 * @target : file to find SDT notes from 2499 * 2500 * This opens the file, initializes 2501 * the ELF and then calls construct_sdt_notes_list. 2502 */ 2503 int get_sdt_note_list(struct list_head *head, const char *target) 2504 { 2505 Elf *elf; 2506 int fd, ret; 2507 2508 fd = open(target, O_RDONLY); 2509 if (fd < 0) 2510 return -EBADF; 2511 2512 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 2513 if (!elf) { 2514 ret = -EBADF; 2515 goto out_close; 2516 } 2517 ret = construct_sdt_notes_list(elf, head); 2518 elf_end(elf); 2519 out_close: 2520 close(fd); 2521 return ret; 2522 } 2523 2524 /** 2525 * cleanup_sdt_note_list : free the sdt notes' list 2526 * @sdt_notes: sdt notes' list 2527 * 2528 * Free up the SDT notes in @sdt_notes. 2529 * Returns the number of SDT notes free'd. 2530 */ 2531 int cleanup_sdt_note_list(struct list_head *sdt_notes) 2532 { 2533 struct sdt_note *tmp, *pos; 2534 int nr_free = 0; 2535 2536 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { 2537 list_del_init(&pos->note_list); 2538 zfree(&pos->args); 2539 zfree(&pos->name); 2540 zfree(&pos->provider); 2541 free(pos); 2542 nr_free++; 2543 } 2544 return nr_free; 2545 } 2546 2547 /** 2548 * sdt_notes__get_count: Counts the number of sdt events 2549 * @start: list_head to sdt_notes list 2550 * 2551 * Returns the number of SDT notes in a list 2552 */ 2553 int sdt_notes__get_count(struct list_head *start) 2554 { 2555 struct sdt_note *sdt_ptr; 2556 int count = 0; 2557 2558 list_for_each_entry(sdt_ptr, start, note_list) 2559 count++; 2560 return count; 2561 } 2562 #endif 2563 2564 void symbol__elf_init(void) 2565 { 2566 elf_version(EV_CURRENT); 2567 } 2568