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