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]; 837 838 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) { 839 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; 840 goto out_elf_end; 841 } 842 843 if (!dso__build_id_equal(dso, build_id)) { 844 pr_debug("%s: build id mismatch for %s.\n", __func__, name); 845 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; 846 goto out_elf_end; 847 } 848 } 849 850 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 851 852 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", 853 NULL); 854 if (ss->symshdr.sh_type != SHT_SYMTAB) 855 ss->symtab = NULL; 856 857 ss->dynsym_idx = 0; 858 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", 859 &ss->dynsym_idx); 860 if (ss->dynshdr.sh_type != SHT_DYNSYM) 861 ss->dynsym = NULL; 862 863 ss->opdidx = 0; 864 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", 865 &ss->opdidx); 866 if (ss->opdshdr.sh_type != SHT_PROGBITS) 867 ss->opdsec = NULL; 868 869 if (dso->kernel == DSO_SPACE__USER) 870 ss->adjust_symbols = true; 871 else 872 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); 873 874 ss->name = strdup(name); 875 if (!ss->name) { 876 dso->load_errno = errno; 877 goto out_elf_end; 878 } 879 880 ss->elf = elf; 881 ss->fd = fd; 882 ss->ehdr = ehdr; 883 ss->type = type; 884 885 return 0; 886 887 out_elf_end: 888 elf_end(elf); 889 out_close: 890 close(fd); 891 return -1; 892 } 893 894 /** 895 * ref_reloc_sym_not_found - has kernel relocation symbol been found. 896 * @kmap: kernel maps and relocation reference symbol 897 * 898 * This function returns %true if we are dealing with the kernel maps and the 899 * relocation reference symbol has not yet been found. Otherwise %false is 900 * returned. 901 */ 902 static bool ref_reloc_sym_not_found(struct kmap *kmap) 903 { 904 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && 905 !kmap->ref_reloc_sym->unrelocated_addr; 906 } 907 908 /** 909 * ref_reloc - kernel relocation offset. 910 * @kmap: kernel maps and relocation reference symbol 911 * 912 * This function returns the offset of kernel addresses as determined by using 913 * the relocation reference symbol i.e. if the kernel has not been relocated 914 * then the return value is zero. 915 */ 916 static u64 ref_reloc(struct kmap *kmap) 917 { 918 if (kmap && kmap->ref_reloc_sym && 919 kmap->ref_reloc_sym->unrelocated_addr) 920 return kmap->ref_reloc_sym->addr - 921 kmap->ref_reloc_sym->unrelocated_addr; 922 return 0; 923 } 924 925 void __weak arch__sym_update(struct symbol *s __maybe_unused, 926 GElf_Sym *sym __maybe_unused) { } 927 928 static int dso__process_kernel_symbol(struct dso *dso, struct map *map, 929 GElf_Sym *sym, GElf_Shdr *shdr, 930 struct maps *kmaps, struct kmap *kmap, 931 struct dso **curr_dsop, struct map **curr_mapp, 932 const char *section_name, 933 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) 934 { 935 struct dso *curr_dso = *curr_dsop; 936 struct map *curr_map; 937 char dso_name[PATH_MAX]; 938 939 /* Adjust symbol to map to file offset */ 940 if (adjust_kernel_syms) 941 sym->st_value -= shdr->sh_addr - shdr->sh_offset; 942 943 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0) 944 return 0; 945 946 if (strcmp(section_name, ".text") == 0) { 947 /* 948 * The initial kernel mapping is based on 949 * kallsyms and identity maps. Overwrite it to 950 * map to the kernel dso. 951 */ 952 if (*remap_kernel && dso->kernel && !kmodule) { 953 *remap_kernel = false; 954 map->start = shdr->sh_addr + ref_reloc(kmap); 955 map->end = map->start + shdr->sh_size; 956 map->pgoff = shdr->sh_offset; 957 map->map_ip = map__map_ip; 958 map->unmap_ip = map__unmap_ip; 959 /* Ensure maps are correctly ordered */ 960 if (kmaps) { 961 map__get(map); 962 maps__remove(kmaps, map); 963 maps__insert(kmaps, map); 964 map__put(map); 965 } 966 } 967 968 /* 969 * The initial module mapping is based on 970 * /proc/modules mapped to offset zero. 971 * Overwrite it to map to the module dso. 972 */ 973 if (*remap_kernel && kmodule) { 974 *remap_kernel = false; 975 map->pgoff = shdr->sh_offset; 976 } 977 978 *curr_mapp = map; 979 *curr_dsop = dso; 980 return 0; 981 } 982 983 if (!kmap) 984 return 0; 985 986 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); 987 988 curr_map = maps__find_by_name(kmaps, dso_name); 989 if (curr_map == NULL) { 990 u64 start = sym->st_value; 991 992 if (kmodule) 993 start += map->start + shdr->sh_offset; 994 995 curr_dso = dso__new(dso_name); 996 if (curr_dso == NULL) 997 return -1; 998 curr_dso->kernel = dso->kernel; 999 curr_dso->long_name = dso->long_name; 1000 curr_dso->long_name_len = dso->long_name_len; 1001 curr_map = map__new2(start, curr_dso); 1002 dso__put(curr_dso); 1003 if (curr_map == NULL) 1004 return -1; 1005 1006 if (curr_dso->kernel) 1007 map__kmap(curr_map)->kmaps = kmaps; 1008 1009 if (adjust_kernel_syms) { 1010 curr_map->start = shdr->sh_addr + ref_reloc(kmap); 1011 curr_map->end = curr_map->start + shdr->sh_size; 1012 curr_map->pgoff = shdr->sh_offset; 1013 } else { 1014 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; 1015 } 1016 curr_dso->symtab_type = dso->symtab_type; 1017 maps__insert(kmaps, curr_map); 1018 /* 1019 * Add it before we drop the referece to curr_map, i.e. while 1020 * we still are sure to have a reference to this DSO via 1021 * *curr_map->dso. 1022 */ 1023 dsos__add(&kmaps->machine->dsos, curr_dso); 1024 /* kmaps already got it */ 1025 map__put(curr_map); 1026 dso__set_loaded(curr_dso); 1027 *curr_mapp = curr_map; 1028 *curr_dsop = curr_dso; 1029 } else 1030 *curr_dsop = curr_map->dso; 1031 1032 return 0; 1033 } 1034 1035 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1036 struct symsrc *runtime_ss, int kmodule) 1037 { 1038 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; 1039 struct maps *kmaps = kmap ? map__kmaps(map) : NULL; 1040 struct map *curr_map = map; 1041 struct dso *curr_dso = dso; 1042 Elf_Data *symstrs, *secstrs; 1043 uint32_t nr_syms; 1044 int err = -1; 1045 uint32_t idx; 1046 GElf_Ehdr ehdr; 1047 GElf_Shdr shdr; 1048 GElf_Shdr tshdr; 1049 Elf_Data *syms, *opddata = NULL; 1050 GElf_Sym sym; 1051 Elf_Scn *sec, *sec_strndx; 1052 Elf *elf; 1053 int nr = 0; 1054 bool remap_kernel = false, adjust_kernel_syms = false; 1055 1056 if (kmap && !kmaps) 1057 return -1; 1058 1059 dso->symtab_type = syms_ss->type; 1060 dso->is_64_bit = syms_ss->is_64_bit; 1061 dso->rel = syms_ss->ehdr.e_type == ET_REL; 1062 1063 /* 1064 * Modules may already have symbols from kallsyms, but those symbols 1065 * have the wrong values for the dso maps, so remove them. 1066 */ 1067 if (kmodule && syms_ss->symtab) 1068 symbols__delete(&dso->symbols); 1069 1070 if (!syms_ss->symtab) { 1071 /* 1072 * If the vmlinux is stripped, fail so we will fall back 1073 * to using kallsyms. The vmlinux runtime symbols aren't 1074 * of much use. 1075 */ 1076 if (dso->kernel) 1077 goto out_elf_end; 1078 1079 syms_ss->symtab = syms_ss->dynsym; 1080 syms_ss->symshdr = syms_ss->dynshdr; 1081 } 1082 1083 elf = syms_ss->elf; 1084 ehdr = syms_ss->ehdr; 1085 sec = syms_ss->symtab; 1086 shdr = syms_ss->symshdr; 1087 1088 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, 1089 ".text", NULL)) 1090 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; 1091 1092 if (runtime_ss->opdsec) 1093 opddata = elf_rawdata(runtime_ss->opdsec, NULL); 1094 1095 syms = elf_getdata(sec, NULL); 1096 if (syms == NULL) 1097 goto out_elf_end; 1098 1099 sec = elf_getscn(elf, shdr.sh_link); 1100 if (sec == NULL) 1101 goto out_elf_end; 1102 1103 symstrs = elf_getdata(sec, NULL); 1104 if (symstrs == NULL) 1105 goto out_elf_end; 1106 1107 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); 1108 if (sec_strndx == NULL) 1109 goto out_elf_end; 1110 1111 secstrs = elf_getdata(sec_strndx, NULL); 1112 if (secstrs == NULL) 1113 goto out_elf_end; 1114 1115 nr_syms = shdr.sh_size / shdr.sh_entsize; 1116 1117 memset(&sym, 0, sizeof(sym)); 1118 1119 /* 1120 * The kernel relocation symbol is needed in advance in order to adjust 1121 * kernel maps correctly. 1122 */ 1123 if (ref_reloc_sym_not_found(kmap)) { 1124 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1125 const char *elf_name = elf_sym__name(&sym, symstrs); 1126 1127 if (strcmp(elf_name, kmap->ref_reloc_sym->name)) 1128 continue; 1129 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; 1130 map->reloc = kmap->ref_reloc_sym->addr - 1131 kmap->ref_reloc_sym->unrelocated_addr; 1132 break; 1133 } 1134 } 1135 1136 /* 1137 * Handle any relocation of vdso necessary because older kernels 1138 * attempted to prelink vdso to its virtual address. 1139 */ 1140 if (dso__is_vdso(dso)) 1141 map->reloc = map->start - dso->text_offset; 1142 1143 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); 1144 /* 1145 * Initial kernel and module mappings do not map to the dso. 1146 * Flag the fixups. 1147 */ 1148 if (dso->kernel) { 1149 remap_kernel = true; 1150 adjust_kernel_syms = dso->adjust_symbols; 1151 } 1152 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1153 struct symbol *f; 1154 const char *elf_name = elf_sym__name(&sym, symstrs); 1155 char *demangled = NULL; 1156 int is_label = elf_sym__is_label(&sym); 1157 const char *section_name; 1158 bool used_opd = false; 1159 1160 if (!is_label && !elf_sym__filter(&sym)) 1161 continue; 1162 1163 /* Reject ARM ELF "mapping symbols": these aren't unique and 1164 * don't identify functions, so will confuse the profile 1165 * output: */ 1166 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { 1167 if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) 1168 && (elf_name[2] == '\0' || elf_name[2] == '.')) 1169 continue; 1170 } 1171 1172 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { 1173 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; 1174 u64 *opd = opddata->d_buf + offset; 1175 sym.st_value = DSO__SWAP(dso, u64, *opd); 1176 sym.st_shndx = elf_addr_to_index(runtime_ss->elf, 1177 sym.st_value); 1178 used_opd = true; 1179 } 1180 /* 1181 * When loading symbols in a data mapping, ABS symbols (which 1182 * has a value of SHN_ABS in its st_shndx) failed at 1183 * elf_getscn(). And it marks the loading as a failure so 1184 * already loaded symbols cannot be fixed up. 1185 * 1186 * I'm not sure what should be done. Just ignore them for now. 1187 * - Namhyung Kim 1188 */ 1189 if (sym.st_shndx == SHN_ABS) 1190 continue; 1191 1192 sec = elf_getscn(runtime_ss->elf, sym.st_shndx); 1193 if (!sec) 1194 goto out_elf_end; 1195 1196 gelf_getshdr(sec, &shdr); 1197 1198 if (is_label && !elf_sec__filter(&shdr, secstrs)) 1199 continue; 1200 1201 section_name = elf_sec__name(&shdr, secstrs); 1202 1203 /* On ARM, symbols for thumb functions have 1 added to 1204 * the symbol address as a flag - remove it */ 1205 if ((ehdr.e_machine == EM_ARM) && 1206 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && 1207 (sym.st_value & 1)) 1208 --sym.st_value; 1209 1210 if (dso->kernel) { 1211 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, 1212 section_name, adjust_kernel_syms, kmodule, &remap_kernel)) 1213 goto out_elf_end; 1214 } else if ((used_opd && runtime_ss->adjust_symbols) || 1215 (!used_opd && syms_ss->adjust_symbols)) { 1216 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1217 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__, 1218 (u64)sym.st_value, (u64)shdr.sh_addr, 1219 (u64)shdr.sh_offset); 1220 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 1221 } 1222 1223 demangled = demangle_sym(dso, kmodule, elf_name); 1224 if (demangled != NULL) 1225 elf_name = demangled; 1226 1227 f = symbol__new(sym.st_value, sym.st_size, 1228 GELF_ST_BIND(sym.st_info), 1229 GELF_ST_TYPE(sym.st_info), elf_name); 1230 free(demangled); 1231 if (!f) 1232 goto out_elf_end; 1233 1234 arch__sym_update(f, &sym); 1235 1236 __symbols__insert(&curr_dso->symbols, f, dso->kernel); 1237 nr++; 1238 } 1239 1240 /* 1241 * For misannotated, zeroed, ASM function sizes. 1242 */ 1243 if (nr > 0) { 1244 symbols__fixup_end(&dso->symbols); 1245 symbols__fixup_duplicate(&dso->symbols); 1246 if (kmap) { 1247 /* 1248 * We need to fixup this here too because we create new 1249 * maps here, for things like vsyscall sections. 1250 */ 1251 maps__fixup_end(kmaps); 1252 } 1253 } 1254 err = nr; 1255 out_elf_end: 1256 return err; 1257 } 1258 1259 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) 1260 { 1261 GElf_Phdr phdr; 1262 size_t i, phdrnum; 1263 int err; 1264 u64 sz; 1265 1266 if (elf_getphdrnum(elf, &phdrnum)) 1267 return -1; 1268 1269 for (i = 0; i < phdrnum; i++) { 1270 if (gelf_getphdr(elf, i, &phdr) == NULL) 1271 return -1; 1272 if (phdr.p_type != PT_LOAD) 1273 continue; 1274 if (exe) { 1275 if (!(phdr.p_flags & PF_X)) 1276 continue; 1277 } else { 1278 if (!(phdr.p_flags & PF_R)) 1279 continue; 1280 } 1281 sz = min(phdr.p_memsz, phdr.p_filesz); 1282 if (!sz) 1283 continue; 1284 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); 1285 if (err) 1286 return err; 1287 } 1288 return 0; 1289 } 1290 1291 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, 1292 bool *is_64_bit) 1293 { 1294 int err; 1295 Elf *elf; 1296 1297 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1298 if (elf == NULL) 1299 return -1; 1300 1301 if (is_64_bit) 1302 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1303 1304 err = elf_read_maps(elf, exe, mapfn, data); 1305 1306 elf_end(elf); 1307 return err; 1308 } 1309 1310 enum dso_type dso__type_fd(int fd) 1311 { 1312 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 1313 GElf_Ehdr ehdr; 1314 Elf_Kind ek; 1315 Elf *elf; 1316 1317 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1318 if (elf == NULL) 1319 goto out; 1320 1321 ek = elf_kind(elf); 1322 if (ek != ELF_K_ELF) 1323 goto out_end; 1324 1325 if (gelf_getclass(elf) == ELFCLASS64) { 1326 dso_type = DSO__TYPE_64BIT; 1327 goto out_end; 1328 } 1329 1330 if (gelf_getehdr(elf, &ehdr) == NULL) 1331 goto out_end; 1332 1333 if (ehdr.e_machine == EM_X86_64) 1334 dso_type = DSO__TYPE_X32BIT; 1335 else 1336 dso_type = DSO__TYPE_32BIT; 1337 out_end: 1338 elf_end(elf); 1339 out: 1340 return dso_type; 1341 } 1342 1343 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) 1344 { 1345 ssize_t r; 1346 size_t n; 1347 int err = -1; 1348 char *buf = malloc(page_size); 1349 1350 if (buf == NULL) 1351 return -1; 1352 1353 if (lseek(to, to_offs, SEEK_SET) != to_offs) 1354 goto out; 1355 1356 if (lseek(from, from_offs, SEEK_SET) != from_offs) 1357 goto out; 1358 1359 while (len) { 1360 n = page_size; 1361 if (len < n) 1362 n = len; 1363 /* Use read because mmap won't work on proc files */ 1364 r = read(from, buf, n); 1365 if (r < 0) 1366 goto out; 1367 if (!r) 1368 break; 1369 n = r; 1370 r = write(to, buf, n); 1371 if (r < 0) 1372 goto out; 1373 if ((size_t)r != n) 1374 goto out; 1375 len -= n; 1376 } 1377 1378 err = 0; 1379 out: 1380 free(buf); 1381 return err; 1382 } 1383 1384 struct kcore { 1385 int fd; 1386 int elfclass; 1387 Elf *elf; 1388 GElf_Ehdr ehdr; 1389 }; 1390 1391 static int kcore__open(struct kcore *kcore, const char *filename) 1392 { 1393 GElf_Ehdr *ehdr; 1394 1395 kcore->fd = open(filename, O_RDONLY); 1396 if (kcore->fd == -1) 1397 return -1; 1398 1399 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); 1400 if (!kcore->elf) 1401 goto out_close; 1402 1403 kcore->elfclass = gelf_getclass(kcore->elf); 1404 if (kcore->elfclass == ELFCLASSNONE) 1405 goto out_end; 1406 1407 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); 1408 if (!ehdr) 1409 goto out_end; 1410 1411 return 0; 1412 1413 out_end: 1414 elf_end(kcore->elf); 1415 out_close: 1416 close(kcore->fd); 1417 return -1; 1418 } 1419 1420 static int kcore__init(struct kcore *kcore, char *filename, int elfclass, 1421 bool temp) 1422 { 1423 kcore->elfclass = elfclass; 1424 1425 if (temp) 1426 kcore->fd = mkstemp(filename); 1427 else 1428 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); 1429 if (kcore->fd == -1) 1430 return -1; 1431 1432 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); 1433 if (!kcore->elf) 1434 goto out_close; 1435 1436 if (!gelf_newehdr(kcore->elf, elfclass)) 1437 goto out_end; 1438 1439 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); 1440 1441 return 0; 1442 1443 out_end: 1444 elf_end(kcore->elf); 1445 out_close: 1446 close(kcore->fd); 1447 unlink(filename); 1448 return -1; 1449 } 1450 1451 static void kcore__close(struct kcore *kcore) 1452 { 1453 elf_end(kcore->elf); 1454 close(kcore->fd); 1455 } 1456 1457 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) 1458 { 1459 GElf_Ehdr *ehdr = &to->ehdr; 1460 GElf_Ehdr *kehdr = &from->ehdr; 1461 1462 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); 1463 ehdr->e_type = kehdr->e_type; 1464 ehdr->e_machine = kehdr->e_machine; 1465 ehdr->e_version = kehdr->e_version; 1466 ehdr->e_entry = 0; 1467 ehdr->e_shoff = 0; 1468 ehdr->e_flags = kehdr->e_flags; 1469 ehdr->e_phnum = count; 1470 ehdr->e_shentsize = 0; 1471 ehdr->e_shnum = 0; 1472 ehdr->e_shstrndx = 0; 1473 1474 if (from->elfclass == ELFCLASS32) { 1475 ehdr->e_phoff = sizeof(Elf32_Ehdr); 1476 ehdr->e_ehsize = sizeof(Elf32_Ehdr); 1477 ehdr->e_phentsize = sizeof(Elf32_Phdr); 1478 } else { 1479 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1480 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1481 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1482 } 1483 1484 if (!gelf_update_ehdr(to->elf, ehdr)) 1485 return -1; 1486 1487 if (!gelf_newphdr(to->elf, count)) 1488 return -1; 1489 1490 return 0; 1491 } 1492 1493 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, 1494 u64 addr, u64 len) 1495 { 1496 GElf_Phdr phdr = { 1497 .p_type = PT_LOAD, 1498 .p_flags = PF_R | PF_W | PF_X, 1499 .p_offset = offset, 1500 .p_vaddr = addr, 1501 .p_paddr = 0, 1502 .p_filesz = len, 1503 .p_memsz = len, 1504 .p_align = page_size, 1505 }; 1506 1507 if (!gelf_update_phdr(kcore->elf, idx, &phdr)) 1508 return -1; 1509 1510 return 0; 1511 } 1512 1513 static off_t kcore__write(struct kcore *kcore) 1514 { 1515 return elf_update(kcore->elf, ELF_C_WRITE); 1516 } 1517 1518 struct phdr_data { 1519 off_t offset; 1520 off_t rel; 1521 u64 addr; 1522 u64 len; 1523 struct list_head node; 1524 struct phdr_data *remaps; 1525 }; 1526 1527 struct sym_data { 1528 u64 addr; 1529 struct list_head node; 1530 }; 1531 1532 struct kcore_copy_info { 1533 u64 stext; 1534 u64 etext; 1535 u64 first_symbol; 1536 u64 last_symbol; 1537 u64 first_module; 1538 u64 first_module_symbol; 1539 u64 last_module_symbol; 1540 size_t phnum; 1541 struct list_head phdrs; 1542 struct list_head syms; 1543 }; 1544 1545 #define kcore_copy__for_each_phdr(k, p) \ 1546 list_for_each_entry((p), &(k)->phdrs, node) 1547 1548 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset) 1549 { 1550 struct phdr_data *p = zalloc(sizeof(*p)); 1551 1552 if (p) { 1553 p->addr = addr; 1554 p->len = len; 1555 p->offset = offset; 1556 } 1557 1558 return p; 1559 } 1560 1561 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci, 1562 u64 addr, u64 len, 1563 off_t offset) 1564 { 1565 struct phdr_data *p = phdr_data__new(addr, len, offset); 1566 1567 if (p) 1568 list_add_tail(&p->node, &kci->phdrs); 1569 1570 return p; 1571 } 1572 1573 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci) 1574 { 1575 struct phdr_data *p, *tmp; 1576 1577 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) { 1578 list_del_init(&p->node); 1579 free(p); 1580 } 1581 } 1582 1583 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci, 1584 u64 addr) 1585 { 1586 struct sym_data *s = zalloc(sizeof(*s)); 1587 1588 if (s) { 1589 s->addr = addr; 1590 list_add_tail(&s->node, &kci->syms); 1591 } 1592 1593 return s; 1594 } 1595 1596 static void kcore_copy__free_syms(struct kcore_copy_info *kci) 1597 { 1598 struct sym_data *s, *tmp; 1599 1600 list_for_each_entry_safe(s, tmp, &kci->syms, node) { 1601 list_del_init(&s->node); 1602 free(s); 1603 } 1604 } 1605 1606 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 1607 u64 start) 1608 { 1609 struct kcore_copy_info *kci = arg; 1610 1611 if (!kallsyms__is_function(type)) 1612 return 0; 1613 1614 if (strchr(name, '[')) { 1615 if (!kci->first_module_symbol || start < kci->first_module_symbol) 1616 kci->first_module_symbol = start; 1617 if (start > kci->last_module_symbol) 1618 kci->last_module_symbol = start; 1619 return 0; 1620 } 1621 1622 if (!kci->first_symbol || start < kci->first_symbol) 1623 kci->first_symbol = start; 1624 1625 if (!kci->last_symbol || start > kci->last_symbol) 1626 kci->last_symbol = start; 1627 1628 if (!strcmp(name, "_stext")) { 1629 kci->stext = start; 1630 return 0; 1631 } 1632 1633 if (!strcmp(name, "_etext")) { 1634 kci->etext = start; 1635 return 0; 1636 } 1637 1638 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start)) 1639 return -1; 1640 1641 return 0; 1642 } 1643 1644 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, 1645 const char *dir) 1646 { 1647 char kallsyms_filename[PATH_MAX]; 1648 1649 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); 1650 1651 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) 1652 return -1; 1653 1654 if (kallsyms__parse(kallsyms_filename, kci, 1655 kcore_copy__process_kallsyms) < 0) 1656 return -1; 1657 1658 return 0; 1659 } 1660 1661 static int kcore_copy__process_modules(void *arg, 1662 const char *name __maybe_unused, 1663 u64 start, u64 size __maybe_unused) 1664 { 1665 struct kcore_copy_info *kci = arg; 1666 1667 if (!kci->first_module || start < kci->first_module) 1668 kci->first_module = start; 1669 1670 return 0; 1671 } 1672 1673 static int kcore_copy__parse_modules(struct kcore_copy_info *kci, 1674 const char *dir) 1675 { 1676 char modules_filename[PATH_MAX]; 1677 1678 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); 1679 1680 if (symbol__restricted_filename(modules_filename, "/proc/modules")) 1681 return -1; 1682 1683 if (modules__parse(modules_filename, kci, 1684 kcore_copy__process_modules) < 0) 1685 return -1; 1686 1687 return 0; 1688 } 1689 1690 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end, 1691 u64 pgoff, u64 s, u64 e) 1692 { 1693 u64 len, offset; 1694 1695 if (s < start || s >= end) 1696 return 0; 1697 1698 offset = (s - start) + pgoff; 1699 len = e < end ? e - s : end - s; 1700 1701 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1; 1702 } 1703 1704 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) 1705 { 1706 struct kcore_copy_info *kci = data; 1707 u64 end = start + len; 1708 struct sym_data *sdat; 1709 1710 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext)) 1711 return -1; 1712 1713 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module, 1714 kci->last_module_symbol)) 1715 return -1; 1716 1717 list_for_each_entry(sdat, &kci->syms, node) { 1718 u64 s = round_down(sdat->addr, page_size); 1719 1720 if (kcore_copy__map(kci, start, end, pgoff, s, s + len)) 1721 return -1; 1722 } 1723 1724 return 0; 1725 } 1726 1727 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) 1728 { 1729 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) 1730 return -1; 1731 1732 return 0; 1733 } 1734 1735 static void kcore_copy__find_remaps(struct kcore_copy_info *kci) 1736 { 1737 struct phdr_data *p, *k = NULL; 1738 u64 kend; 1739 1740 if (!kci->stext) 1741 return; 1742 1743 /* Find phdr that corresponds to the kernel map (contains stext) */ 1744 kcore_copy__for_each_phdr(kci, p) { 1745 u64 pend = p->addr + p->len - 1; 1746 1747 if (p->addr <= kci->stext && pend >= kci->stext) { 1748 k = p; 1749 break; 1750 } 1751 } 1752 1753 if (!k) 1754 return; 1755 1756 kend = k->offset + k->len; 1757 1758 /* Find phdrs that remap the kernel */ 1759 kcore_copy__for_each_phdr(kci, p) { 1760 u64 pend = p->offset + p->len; 1761 1762 if (p == k) 1763 continue; 1764 1765 if (p->offset >= k->offset && pend <= kend) 1766 p->remaps = k; 1767 } 1768 } 1769 1770 static void kcore_copy__layout(struct kcore_copy_info *kci) 1771 { 1772 struct phdr_data *p; 1773 off_t rel = 0; 1774 1775 kcore_copy__find_remaps(kci); 1776 1777 kcore_copy__for_each_phdr(kci, p) { 1778 if (!p->remaps) { 1779 p->rel = rel; 1780 rel += p->len; 1781 } 1782 kci->phnum += 1; 1783 } 1784 1785 kcore_copy__for_each_phdr(kci, p) { 1786 struct phdr_data *k = p->remaps; 1787 1788 if (k) 1789 p->rel = p->offset - k->offset + k->rel; 1790 } 1791 } 1792 1793 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 1794 Elf *elf) 1795 { 1796 if (kcore_copy__parse_kallsyms(kci, dir)) 1797 return -1; 1798 1799 if (kcore_copy__parse_modules(kci, dir)) 1800 return -1; 1801 1802 if (kci->stext) 1803 kci->stext = round_down(kci->stext, page_size); 1804 else 1805 kci->stext = round_down(kci->first_symbol, page_size); 1806 1807 if (kci->etext) { 1808 kci->etext = round_up(kci->etext, page_size); 1809 } else if (kci->last_symbol) { 1810 kci->etext = round_up(kci->last_symbol, page_size); 1811 kci->etext += page_size; 1812 } 1813 1814 if (kci->first_module_symbol && 1815 (!kci->first_module || kci->first_module_symbol < kci->first_module)) 1816 kci->first_module = kci->first_module_symbol; 1817 1818 kci->first_module = round_down(kci->first_module, page_size); 1819 1820 if (kci->last_module_symbol) { 1821 kci->last_module_symbol = round_up(kci->last_module_symbol, 1822 page_size); 1823 kci->last_module_symbol += page_size; 1824 } 1825 1826 if (!kci->stext || !kci->etext) 1827 return -1; 1828 1829 if (kci->first_module && !kci->last_module_symbol) 1830 return -1; 1831 1832 if (kcore_copy__read_maps(kci, elf)) 1833 return -1; 1834 1835 kcore_copy__layout(kci); 1836 1837 return 0; 1838 } 1839 1840 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, 1841 const char *name) 1842 { 1843 char from_filename[PATH_MAX]; 1844 char to_filename[PATH_MAX]; 1845 1846 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1847 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1848 1849 return copyfile_mode(from_filename, to_filename, 0400); 1850 } 1851 1852 static int kcore_copy__unlink(const char *dir, const char *name) 1853 { 1854 char filename[PATH_MAX]; 1855 1856 scnprintf(filename, PATH_MAX, "%s/%s", dir, name); 1857 1858 return unlink(filename); 1859 } 1860 1861 static int kcore_copy__compare_fds(int from, int to) 1862 { 1863 char *buf_from; 1864 char *buf_to; 1865 ssize_t ret; 1866 size_t len; 1867 int err = -1; 1868 1869 buf_from = malloc(page_size); 1870 buf_to = malloc(page_size); 1871 if (!buf_from || !buf_to) 1872 goto out; 1873 1874 while (1) { 1875 /* Use read because mmap won't work on proc files */ 1876 ret = read(from, buf_from, page_size); 1877 if (ret < 0) 1878 goto out; 1879 1880 if (!ret) 1881 break; 1882 1883 len = ret; 1884 1885 if (readn(to, buf_to, len) != (int)len) 1886 goto out; 1887 1888 if (memcmp(buf_from, buf_to, len)) 1889 goto out; 1890 } 1891 1892 err = 0; 1893 out: 1894 free(buf_to); 1895 free(buf_from); 1896 return err; 1897 } 1898 1899 static int kcore_copy__compare_files(const char *from_filename, 1900 const char *to_filename) 1901 { 1902 int from, to, err = -1; 1903 1904 from = open(from_filename, O_RDONLY); 1905 if (from < 0) 1906 return -1; 1907 1908 to = open(to_filename, O_RDONLY); 1909 if (to < 0) 1910 goto out_close_from; 1911 1912 err = kcore_copy__compare_fds(from, to); 1913 1914 close(to); 1915 out_close_from: 1916 close(from); 1917 return err; 1918 } 1919 1920 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, 1921 const char *name) 1922 { 1923 char from_filename[PATH_MAX]; 1924 char to_filename[PATH_MAX]; 1925 1926 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 1927 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 1928 1929 return kcore_copy__compare_files(from_filename, to_filename); 1930 } 1931 1932 /** 1933 * kcore_copy - copy kallsyms, modules and kcore from one directory to another. 1934 * @from_dir: from directory 1935 * @to_dir: to directory 1936 * 1937 * This function copies kallsyms, modules and kcore files from one directory to 1938 * another. kallsyms and modules are copied entirely. Only code segments are 1939 * copied from kcore. It is assumed that two segments suffice: one for the 1940 * kernel proper and one for all the modules. The code segments are determined 1941 * from kallsyms and modules files. The kernel map starts at _stext or the 1942 * lowest function symbol, and ends at _etext or the highest function symbol. 1943 * The module map starts at the lowest module address and ends at the highest 1944 * module symbol. Start addresses are rounded down to the nearest page. End 1945 * addresses are rounded up to the nearest page. An extra page is added to the 1946 * highest kernel symbol and highest module symbol to, hopefully, encompass that 1947 * symbol too. Because it contains only code sections, the resulting kcore is 1948 * unusual. One significant peculiarity is that the mapping (start -> pgoff) 1949 * is not the same for the kernel map and the modules map. That happens because 1950 * the data is copied adjacently whereas the original kcore has gaps. Finally, 1951 * kallsyms and modules files are compared with their copies to check that 1952 * modules have not been loaded or unloaded while the copies were taking place. 1953 * 1954 * Return: %0 on success, %-1 on failure. 1955 */ 1956 int kcore_copy(const char *from_dir, const char *to_dir) 1957 { 1958 struct kcore kcore; 1959 struct kcore extract; 1960 int idx = 0, err = -1; 1961 off_t offset, sz; 1962 struct kcore_copy_info kci = { .stext = 0, }; 1963 char kcore_filename[PATH_MAX]; 1964 char extract_filename[PATH_MAX]; 1965 struct phdr_data *p; 1966 1967 INIT_LIST_HEAD(&kci.phdrs); 1968 INIT_LIST_HEAD(&kci.syms); 1969 1970 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) 1971 return -1; 1972 1973 if (kcore_copy__copy_file(from_dir, to_dir, "modules")) 1974 goto out_unlink_kallsyms; 1975 1976 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); 1977 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); 1978 1979 if (kcore__open(&kcore, kcore_filename)) 1980 goto out_unlink_modules; 1981 1982 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) 1983 goto out_kcore_close; 1984 1985 if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) 1986 goto out_kcore_close; 1987 1988 if (kcore__copy_hdr(&kcore, &extract, kci.phnum)) 1989 goto out_extract_close; 1990 1991 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) + 1992 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT); 1993 offset = round_up(offset, page_size); 1994 1995 kcore_copy__for_each_phdr(&kci, p) { 1996 off_t offs = p->rel + offset; 1997 1998 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len)) 1999 goto out_extract_close; 2000 } 2001 2002 sz = kcore__write(&extract); 2003 if (sz < 0 || sz > offset) 2004 goto out_extract_close; 2005 2006 kcore_copy__for_each_phdr(&kci, p) { 2007 off_t offs = p->rel + offset; 2008 2009 if (p->remaps) 2010 continue; 2011 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len)) 2012 goto out_extract_close; 2013 } 2014 2015 if (kcore_copy__compare_file(from_dir, to_dir, "modules")) 2016 goto out_extract_close; 2017 2018 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) 2019 goto out_extract_close; 2020 2021 err = 0; 2022 2023 out_extract_close: 2024 kcore__close(&extract); 2025 if (err) 2026 unlink(extract_filename); 2027 out_kcore_close: 2028 kcore__close(&kcore); 2029 out_unlink_modules: 2030 if (err) 2031 kcore_copy__unlink(to_dir, "modules"); 2032 out_unlink_kallsyms: 2033 if (err) 2034 kcore_copy__unlink(to_dir, "kallsyms"); 2035 2036 kcore_copy__free_phdrs(&kci); 2037 kcore_copy__free_syms(&kci); 2038 2039 return err; 2040 } 2041 2042 int kcore_extract__create(struct kcore_extract *kce) 2043 { 2044 struct kcore kcore; 2045 struct kcore extract; 2046 size_t count = 1; 2047 int idx = 0, err = -1; 2048 off_t offset = page_size, sz; 2049 2050 if (kcore__open(&kcore, kce->kcore_filename)) 2051 return -1; 2052 2053 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); 2054 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) 2055 goto out_kcore_close; 2056 2057 if (kcore__copy_hdr(&kcore, &extract, count)) 2058 goto out_extract_close; 2059 2060 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) 2061 goto out_extract_close; 2062 2063 sz = kcore__write(&extract); 2064 if (sz < 0 || sz > offset) 2065 goto out_extract_close; 2066 2067 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) 2068 goto out_extract_close; 2069 2070 err = 0; 2071 2072 out_extract_close: 2073 kcore__close(&extract); 2074 if (err) 2075 unlink(kce->extract_filename); 2076 out_kcore_close: 2077 kcore__close(&kcore); 2078 2079 return err; 2080 } 2081 2082 void kcore_extract__delete(struct kcore_extract *kce) 2083 { 2084 unlink(kce->extract_filename); 2085 } 2086 2087 #ifdef HAVE_GELF_GETNOTE_SUPPORT 2088 2089 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off) 2090 { 2091 if (!base_off) 2092 return; 2093 2094 if (tmp->bit32) 2095 tmp->addr.a32[SDT_NOTE_IDX_LOC] = 2096 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off - 2097 tmp->addr.a32[SDT_NOTE_IDX_BASE]; 2098 else 2099 tmp->addr.a64[SDT_NOTE_IDX_LOC] = 2100 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off - 2101 tmp->addr.a64[SDT_NOTE_IDX_BASE]; 2102 } 2103 2104 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr, 2105 GElf_Addr base_off) 2106 { 2107 if (!base_off) 2108 return; 2109 2110 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR]) 2111 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2112 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR]) 2113 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2114 } 2115 2116 /** 2117 * populate_sdt_note : Parse raw data and identify SDT note 2118 * @elf: elf of the opened file 2119 * @data: raw data of a section with description offset applied 2120 * @len: note description size 2121 * @type: type of the note 2122 * @sdt_notes: List to add the SDT note 2123 * 2124 * Responsible for parsing the @data in section .note.stapsdt in @elf and 2125 * if its an SDT note, it appends to @sdt_notes list. 2126 */ 2127 static int populate_sdt_note(Elf **elf, const char *data, size_t len, 2128 struct list_head *sdt_notes) 2129 { 2130 const char *provider, *name, *args; 2131 struct sdt_note *tmp = NULL; 2132 GElf_Ehdr ehdr; 2133 GElf_Shdr shdr; 2134 int ret = -EINVAL; 2135 2136 union { 2137 Elf64_Addr a64[NR_ADDR]; 2138 Elf32_Addr a32[NR_ADDR]; 2139 } buf; 2140 2141 Elf_Data dst = { 2142 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, 2143 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), 2144 .d_off = 0, .d_align = 0 2145 }; 2146 Elf_Data src = { 2147 .d_buf = (void *) data, .d_type = ELF_T_ADDR, 2148 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, 2149 .d_align = 0 2150 }; 2151 2152 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); 2153 if (!tmp) { 2154 ret = -ENOMEM; 2155 goto out_err; 2156 } 2157 2158 INIT_LIST_HEAD(&tmp->note_list); 2159 2160 if (len < dst.d_size + 3) 2161 goto out_free_note; 2162 2163 /* Translation from file representation to memory representation */ 2164 if (gelf_xlatetom(*elf, &dst, &src, 2165 elf_getident(*elf, NULL)[EI_DATA]) == NULL) { 2166 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); 2167 goto out_free_note; 2168 } 2169 2170 /* Populate the fields of sdt_note */ 2171 provider = data + dst.d_size; 2172 2173 name = (const char *)memchr(provider, '\0', data + len - provider); 2174 if (name++ == NULL) 2175 goto out_free_note; 2176 2177 tmp->provider = strdup(provider); 2178 if (!tmp->provider) { 2179 ret = -ENOMEM; 2180 goto out_free_note; 2181 } 2182 tmp->name = strdup(name); 2183 if (!tmp->name) { 2184 ret = -ENOMEM; 2185 goto out_free_prov; 2186 } 2187 2188 args = memchr(name, '\0', data + len - name); 2189 2190 /* 2191 * There is no argument if: 2192 * - We reached the end of the note; 2193 * - There is not enough room to hold a potential string; 2194 * - The argument string is empty or just contains ':'. 2195 */ 2196 if (args == NULL || data + len - args < 2 || 2197 args[1] == ':' || args[1] == '\0') 2198 tmp->args = NULL; 2199 else { 2200 tmp->args = strdup(++args); 2201 if (!tmp->args) { 2202 ret = -ENOMEM; 2203 goto out_free_name; 2204 } 2205 } 2206 2207 if (gelf_getclass(*elf) == ELFCLASS32) { 2208 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); 2209 tmp->bit32 = true; 2210 } else { 2211 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); 2212 tmp->bit32 = false; 2213 } 2214 2215 if (!gelf_getehdr(*elf, &ehdr)) { 2216 pr_debug("%s : cannot get elf header.\n", __func__); 2217 ret = -EBADF; 2218 goto out_free_args; 2219 } 2220 2221 /* Adjust the prelink effect : 2222 * Find out the .stapsdt.base section. 2223 * This scn will help us to handle prelinking (if present). 2224 * Compare the retrieved file offset of the base section with the 2225 * base address in the description of the SDT note. If its different, 2226 * then accordingly, adjust the note location. 2227 */ 2228 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) 2229 sdt_adjust_loc(tmp, shdr.sh_offset); 2230 2231 /* Adjust reference counter offset */ 2232 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) 2233 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset); 2234 2235 list_add_tail(&tmp->note_list, sdt_notes); 2236 return 0; 2237 2238 out_free_args: 2239 zfree(&tmp->args); 2240 out_free_name: 2241 zfree(&tmp->name); 2242 out_free_prov: 2243 zfree(&tmp->provider); 2244 out_free_note: 2245 free(tmp); 2246 out_err: 2247 return ret; 2248 } 2249 2250 /** 2251 * construct_sdt_notes_list : constructs a list of SDT notes 2252 * @elf : elf to look into 2253 * @sdt_notes : empty list_head 2254 * 2255 * Scans the sections in 'elf' for the section 2256 * .note.stapsdt. It, then calls populate_sdt_note to find 2257 * out the SDT events and populates the 'sdt_notes'. 2258 */ 2259 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) 2260 { 2261 GElf_Ehdr ehdr; 2262 Elf_Scn *scn = NULL; 2263 Elf_Data *data; 2264 GElf_Shdr shdr; 2265 size_t shstrndx, next; 2266 GElf_Nhdr nhdr; 2267 size_t name_off, desc_off, offset; 2268 int ret = 0; 2269 2270 if (gelf_getehdr(elf, &ehdr) == NULL) { 2271 ret = -EBADF; 2272 goto out_ret; 2273 } 2274 if (elf_getshdrstrndx(elf, &shstrndx) != 0) { 2275 ret = -EBADF; 2276 goto out_ret; 2277 } 2278 2279 /* Look for the required section */ 2280 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); 2281 if (!scn) { 2282 ret = -ENOENT; 2283 goto out_ret; 2284 } 2285 2286 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { 2287 ret = -ENOENT; 2288 goto out_ret; 2289 } 2290 2291 data = elf_getdata(scn, NULL); 2292 2293 /* Get the SDT notes */ 2294 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, 2295 &desc_off)) > 0; offset = next) { 2296 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && 2297 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, 2298 sizeof(SDT_NOTE_NAME))) { 2299 /* Check the type of the note */ 2300 if (nhdr.n_type != SDT_NOTE_TYPE) 2301 goto out_ret; 2302 2303 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), 2304 nhdr.n_descsz, sdt_notes); 2305 if (ret < 0) 2306 goto out_ret; 2307 } 2308 } 2309 if (list_empty(sdt_notes)) 2310 ret = -ENOENT; 2311 2312 out_ret: 2313 return ret; 2314 } 2315 2316 /** 2317 * get_sdt_note_list : Wrapper to construct a list of sdt notes 2318 * @head : empty list_head 2319 * @target : file to find SDT notes from 2320 * 2321 * This opens the file, initializes 2322 * the ELF and then calls construct_sdt_notes_list. 2323 */ 2324 int get_sdt_note_list(struct list_head *head, const char *target) 2325 { 2326 Elf *elf; 2327 int fd, ret; 2328 2329 fd = open(target, O_RDONLY); 2330 if (fd < 0) 2331 return -EBADF; 2332 2333 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 2334 if (!elf) { 2335 ret = -EBADF; 2336 goto out_close; 2337 } 2338 ret = construct_sdt_notes_list(elf, head); 2339 elf_end(elf); 2340 out_close: 2341 close(fd); 2342 return ret; 2343 } 2344 2345 /** 2346 * cleanup_sdt_note_list : free the sdt notes' list 2347 * @sdt_notes: sdt notes' list 2348 * 2349 * Free up the SDT notes in @sdt_notes. 2350 * Returns the number of SDT notes free'd. 2351 */ 2352 int cleanup_sdt_note_list(struct list_head *sdt_notes) 2353 { 2354 struct sdt_note *tmp, *pos; 2355 int nr_free = 0; 2356 2357 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { 2358 list_del_init(&pos->note_list); 2359 zfree(&pos->name); 2360 zfree(&pos->provider); 2361 free(pos); 2362 nr_free++; 2363 } 2364 return nr_free; 2365 } 2366 2367 /** 2368 * sdt_notes__get_count: Counts the number of sdt events 2369 * @start: list_head to sdt_notes list 2370 * 2371 * Returns the number of SDT notes in a list 2372 */ 2373 int sdt_notes__get_count(struct list_head *start) 2374 { 2375 struct sdt_note *sdt_ptr; 2376 int count = 0; 2377 2378 list_for_each_entry(sdt_ptr, start, note_list) 2379 count++; 2380 return count; 2381 } 2382 #endif 2383 2384 void symbol__elf_init(void) 2385 { 2386 elf_version(EV_CURRENT); 2387 } 2388