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