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