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