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