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-ocaml.h" 16 #include "demangle-java.h" 17 #include "demangle-rust.h" 18 #include "machine.h" 19 #include "vdso.h" 20 #include "debug.h" 21 #include "util/copyfile.h" 22 #include <linux/ctype.h> 23 #include <linux/kernel.h> 24 #include <linux/zalloc.h> 25 #include <symbol/kallsyms.h> 26 #include <internal/lib.h> 27 28 #ifndef EM_AARCH64 29 #define EM_AARCH64 183 /* ARM 64 bit */ 30 #endif 31 32 #ifndef ELF32_ST_VISIBILITY 33 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03) 34 #endif 35 36 /* For ELF64 the definitions are the same. */ 37 #ifndef ELF64_ST_VISIBILITY 38 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o) 39 #endif 40 41 /* How to extract information held in the st_other field. */ 42 #ifndef GELF_ST_VISIBILITY 43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val) 44 #endif 45 46 typedef Elf64_Nhdr GElf_Nhdr; 47 48 #ifndef DMGL_PARAMS 49 #define DMGL_NO_OPTS 0 /* For readability... */ 50 #define DMGL_PARAMS (1 << 0) /* Include function args */ 51 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ 52 #endif 53 54 #ifdef HAVE_LIBBFD_SUPPORT 55 #define PACKAGE 'perf' 56 #include <bfd.h> 57 #else 58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT 59 extern char *cplus_demangle(const char *, int); 60 61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i) 62 { 63 return cplus_demangle(c, i); 64 } 65 #else 66 #ifdef NO_DEMANGLE 67 static inline char *bfd_demangle(void __maybe_unused *v, 68 const char __maybe_unused *c, 69 int __maybe_unused i) 70 { 71 return NULL; 72 } 73 #endif 74 #endif 75 #endif 76 77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT 78 static int elf_getphdrnum(Elf *elf, size_t *dst) 79 { 80 GElf_Ehdr gehdr; 81 GElf_Ehdr *ehdr; 82 83 ehdr = gelf_getehdr(elf, &gehdr); 84 if (!ehdr) 85 return -1; 86 87 *dst = ehdr->e_phnum; 88 89 return 0; 90 } 91 #endif 92 93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT 94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused) 95 { 96 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__); 97 return -1; 98 } 99 #endif 100 101 #ifndef NT_GNU_BUILD_ID 102 #define NT_GNU_BUILD_ID 3 103 #endif 104 105 /** 106 * elf_symtab__for_each_symbol - iterate thru all the symbols 107 * 108 * @syms: struct elf_symtab instance to iterate 109 * @idx: uint32_t idx 110 * @sym: GElf_Sym iterator 111 */ 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \ 113 for (idx = 0, gelf_getsym(syms, idx, &sym);\ 114 idx < nr_syms; \ 115 idx++, gelf_getsym(syms, idx, &sym)) 116 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym) 118 { 119 return GELF_ST_TYPE(sym->st_info); 120 } 121 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym) 123 { 124 return GELF_ST_VISIBILITY(sym->st_other); 125 } 126 127 #ifndef STT_GNU_IFUNC 128 #define STT_GNU_IFUNC 10 129 #endif 130 131 static inline int elf_sym__is_function(const GElf_Sym *sym) 132 { 133 return (elf_sym__type(sym) == STT_FUNC || 134 elf_sym__type(sym) == STT_GNU_IFUNC) && 135 sym->st_name != 0 && 136 sym->st_shndx != SHN_UNDEF; 137 } 138 139 static inline bool elf_sym__is_object(const GElf_Sym *sym) 140 { 141 return elf_sym__type(sym) == STT_OBJECT && 142 sym->st_name != 0 && 143 sym->st_shndx != SHN_UNDEF; 144 } 145 146 static inline int elf_sym__is_label(const GElf_Sym *sym) 147 { 148 return elf_sym__type(sym) == STT_NOTYPE && 149 sym->st_name != 0 && 150 sym->st_shndx != SHN_UNDEF && 151 sym->st_shndx != SHN_ABS && 152 elf_sym__visibility(sym) != STV_HIDDEN && 153 elf_sym__visibility(sym) != STV_INTERNAL; 154 } 155 156 static bool elf_sym__filter(GElf_Sym *sym) 157 { 158 return elf_sym__is_function(sym) || elf_sym__is_object(sym); 159 } 160 161 static inline const char *elf_sym__name(const GElf_Sym *sym, 162 const Elf_Data *symstrs) 163 { 164 return symstrs->d_buf + sym->st_name; 165 } 166 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr, 168 const Elf_Data *secstrs) 169 { 170 return secstrs->d_buf + shdr->sh_name; 171 } 172 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr, 174 const Elf_Data *secstrs) 175 { 176 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL; 177 } 178 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr, 180 const Elf_Data *secstrs) 181 { 182 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL; 183 } 184 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs) 186 { 187 return elf_sec__is_text(shdr, secstrs) || 188 elf_sec__is_data(shdr, secstrs); 189 } 190 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) 192 { 193 Elf_Scn *sec = NULL; 194 GElf_Shdr shdr; 195 size_t cnt = 1; 196 197 while ((sec = elf_nextscn(elf, sec)) != NULL) { 198 gelf_getshdr(sec, &shdr); 199 200 if ((addr >= shdr.sh_addr) && 201 (addr < (shdr.sh_addr + shdr.sh_size))) 202 return cnt; 203 204 ++cnt; 205 } 206 207 return -1; 208 } 209 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, 211 GElf_Shdr *shp, const char *name, size_t *idx) 212 { 213 Elf_Scn *sec = NULL; 214 size_t cnt = 1; 215 216 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 217 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) 218 return NULL; 219 220 while ((sec = elf_nextscn(elf, sec)) != NULL) { 221 char *str; 222 223 gelf_getshdr(sec, shp); 224 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); 225 if (str && !strcmp(name, str)) { 226 if (idx) 227 *idx = cnt; 228 return sec; 229 } 230 ++cnt; 231 } 232 233 return NULL; 234 } 235 236 bool filename__has_section(const char *filename, const char *sec) 237 { 238 int fd; 239 Elf *elf; 240 GElf_Ehdr ehdr; 241 GElf_Shdr shdr; 242 bool found = false; 243 244 fd = open(filename, O_RDONLY); 245 if (fd < 0) 246 return false; 247 248 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 249 if (elf == NULL) 250 goto out; 251 252 if (gelf_getehdr(elf, &ehdr) == NULL) 253 goto elf_out; 254 255 found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL); 256 257 elf_out: 258 elf_end(elf); 259 out: 260 close(fd); 261 return found; 262 } 263 264 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr) 265 { 266 size_t i, phdrnum; 267 u64 sz; 268 269 if (elf_getphdrnum(elf, &phdrnum)) 270 return -1; 271 272 for (i = 0; i < phdrnum; i++) { 273 if (gelf_getphdr(elf, i, phdr) == NULL) 274 return -1; 275 276 if (phdr->p_type != PT_LOAD) 277 continue; 278 279 sz = max(phdr->p_memsz, phdr->p_filesz); 280 if (!sz) 281 continue; 282 283 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz)) 284 return 0; 285 } 286 287 /* Not found any valid program header */ 288 return -1; 289 } 290 291 static bool want_demangle(bool is_kernel_sym) 292 { 293 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle; 294 } 295 296 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 297 { 298 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS; 299 char *demangled = NULL; 300 301 /* 302 * We need to figure out if the object was created from C++ sources 303 * DWARF DW_compile_unit has this, but we don't always have access 304 * to it... 305 */ 306 if (!want_demangle(dso->kernel || kmodule)) 307 return demangled; 308 309 demangled = bfd_demangle(NULL, elf_name, demangle_flags); 310 if (demangled == NULL) { 311 demangled = ocaml_demangle_sym(elf_name); 312 if (demangled == NULL) { 313 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET); 314 } 315 } 316 else if (rust_is_mangled(demangled)) 317 /* 318 * Input to Rust demangling is the BFD-demangled 319 * name which it Rust-demangles in place. 320 */ 321 rust_demangle_sym(demangled); 322 323 return demangled; 324 } 325 326 struct rel_info { 327 u32 nr_entries; 328 u32 *sorted; 329 bool is_rela; 330 Elf_Data *reldata; 331 GElf_Rela rela; 332 GElf_Rel rel; 333 }; 334 335 static u32 get_rel_symidx(struct rel_info *ri, u32 idx) 336 { 337 idx = ri->sorted ? ri->sorted[idx] : idx; 338 if (ri->is_rela) { 339 gelf_getrela(ri->reldata, idx, &ri->rela); 340 return GELF_R_SYM(ri->rela.r_info); 341 } 342 gelf_getrel(ri->reldata, idx, &ri->rel); 343 return GELF_R_SYM(ri->rel.r_info); 344 } 345 346 static u64 get_rel_offset(struct rel_info *ri, u32 x) 347 { 348 if (ri->is_rela) { 349 GElf_Rela rela; 350 351 gelf_getrela(ri->reldata, x, &rela); 352 return rela.r_offset; 353 } else { 354 GElf_Rel rel; 355 356 gelf_getrel(ri->reldata, x, &rel); 357 return rel.r_offset; 358 } 359 } 360 361 static int rel_cmp(const void *a, const void *b, void *r) 362 { 363 struct rel_info *ri = r; 364 u64 a_offset = get_rel_offset(ri, *(const u32 *)a); 365 u64 b_offset = get_rel_offset(ri, *(const u32 *)b); 366 367 return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0); 368 } 369 370 static int sort_rel(struct rel_info *ri) 371 { 372 size_t sz = sizeof(ri->sorted[0]); 373 u32 i; 374 375 ri->sorted = calloc(ri->nr_entries, sz); 376 if (!ri->sorted) 377 return -1; 378 for (i = 0; i < ri->nr_entries; i++) 379 ri->sorted[i] = i; 380 qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri); 381 return 0; 382 } 383 384 /* 385 * For x86_64, the GNU linker is putting IFUNC information in the relocation 386 * addend. 387 */ 388 static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri) 389 { 390 return ehdr->e_machine == EM_X86_64 && ri->is_rela && 391 GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE; 392 } 393 394 static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr, 395 struct rel_info *ri, char *buf, size_t buf_sz) 396 { 397 u64 addr = ri->rela.r_addend; 398 struct symbol *sym; 399 GElf_Phdr phdr; 400 401 if (!addend_may_be_ifunc(ehdr, ri)) 402 return false; 403 404 if (elf_read_program_header(elf, addr, &phdr)) 405 return false; 406 407 addr -= phdr.p_vaddr - phdr.p_offset; 408 409 sym = dso__find_symbol_nocache(dso, addr); 410 411 /* Expecting the address to be an IFUNC or IFUNC alias */ 412 if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias)) 413 return false; 414 415 snprintf(buf, buf_sz, "%s@plt", sym->name); 416 417 return true; 418 } 419 420 static void exit_rel(struct rel_info *ri) 421 { 422 free(ri->sorted); 423 } 424 425 static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt, 426 u64 *plt_header_size, u64 *plt_entry_size) 427 { 428 switch (ehdr->e_machine) { 429 case EM_ARM: 430 *plt_header_size = 20; 431 *plt_entry_size = 12; 432 return true; 433 case EM_AARCH64: 434 *plt_header_size = 32; 435 *plt_entry_size = 16; 436 return true; 437 case EM_SPARC: 438 *plt_header_size = 48; 439 *plt_entry_size = 12; 440 return true; 441 case EM_SPARCV9: 442 *plt_header_size = 128; 443 *plt_entry_size = 32; 444 return true; 445 case EM_386: 446 case EM_X86_64: 447 *plt_entry_size = shdr_plt->sh_entsize; 448 /* Size is 8 or 16, if not, assume alignment indicates size */ 449 if (*plt_entry_size != 8 && *plt_entry_size != 16) 450 *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16; 451 *plt_header_size = *plt_entry_size; 452 break; 453 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */ 454 *plt_header_size = shdr_plt->sh_entsize; 455 *plt_entry_size = shdr_plt->sh_entsize; 456 break; 457 } 458 if (*plt_entry_size) 459 return true; 460 pr_debug("Missing PLT entry size for %s\n", dso->long_name); 461 return false; 462 } 463 464 static bool machine_is_x86(GElf_Half e_machine) 465 { 466 return e_machine == EM_386 || e_machine == EM_X86_64; 467 } 468 469 /* 470 * We need to check if we have a .dynsym, so that we can handle the 471 * .plt, synthesizing its symbols, that aren't on the symtabs (be it 472 * .dynsym or .symtab). 473 * And always look at the original dso, not at debuginfo packages, that 474 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS). 475 */ 476 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) 477 { 478 uint32_t idx; 479 GElf_Sym sym; 480 u64 plt_offset, plt_header_size, plt_entry_size; 481 GElf_Shdr shdr_plt, plt_sec_shdr; 482 struct symbol *f, *plt_sym; 483 GElf_Shdr shdr_rel_plt, shdr_dynsym; 484 Elf_Data *syms, *symstrs; 485 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym; 486 size_t dynsym_idx; 487 GElf_Ehdr ehdr; 488 char sympltname[1024]; 489 Elf *elf; 490 int nr = 0, err = -1; 491 struct rel_info ri = { .is_rela = false }; 492 bool lazy_plt; 493 494 elf = ss->elf; 495 ehdr = ss->ehdr; 496 497 if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL)) 498 return 0; 499 500 /* 501 * A symbol from a previous section (e.g. .init) can have been expanded 502 * by symbols__fixup_end() to overlap .plt. Truncate it before adding 503 * a symbol for .plt header. 504 */ 505 f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset); 506 if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset) 507 f->end = shdr_plt.sh_offset; 508 509 if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size)) 510 return 0; 511 512 /* Add a symbol for .plt header */ 513 plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt"); 514 if (!plt_sym) 515 goto out_elf_end; 516 symbols__insert(&dso->symbols, plt_sym); 517 518 /* Only x86 has .plt.sec */ 519 if (machine_is_x86(ehdr.e_machine) && 520 elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) { 521 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size)) 522 return 0; 523 /* Extend .plt symbol to entire .plt */ 524 plt_sym->end = plt_sym->start + shdr_plt.sh_size; 525 /* Use .plt.sec offset */ 526 plt_offset = plt_sec_shdr.sh_offset; 527 lazy_plt = false; 528 } else { 529 plt_offset = shdr_plt.sh_offset; 530 lazy_plt = true; 531 } 532 533 scn_dynsym = ss->dynsym; 534 shdr_dynsym = ss->dynshdr; 535 dynsym_idx = ss->dynsym_idx; 536 537 if (scn_dynsym == NULL) 538 return 0; 539 540 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 541 ".rela.plt", NULL); 542 if (scn_plt_rel == NULL) { 543 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, 544 ".rel.plt", NULL); 545 if (scn_plt_rel == NULL) 546 return 0; 547 } 548 549 if (shdr_rel_plt.sh_type != SHT_RELA && 550 shdr_rel_plt.sh_type != SHT_REL) 551 return 0; 552 553 if (shdr_rel_plt.sh_link != dynsym_idx) 554 goto out_elf_end; 555 556 /* 557 * Fetch the relocation section to find the idxes to the GOT 558 * and the symbols in the .dynsym they refer to. 559 */ 560 ri.reldata = elf_getdata(scn_plt_rel, NULL); 561 if (!ri.reldata) 562 goto out_elf_end; 563 564 syms = elf_getdata(scn_dynsym, NULL); 565 if (syms == NULL) 566 goto out_elf_end; 567 568 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link); 569 if (scn_symstrs == NULL) 570 goto out_elf_end; 571 572 symstrs = elf_getdata(scn_symstrs, NULL); 573 if (symstrs == NULL) 574 goto out_elf_end; 575 576 if (symstrs->d_size == 0) 577 goto out_elf_end; 578 579 ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; 580 581 ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA; 582 583 if (lazy_plt) { 584 /* 585 * Assume a .plt with the same number of entries as the number 586 * of relocation entries is not lazy and does not have a header. 587 */ 588 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size) 589 dso__delete_symbol(dso, plt_sym); 590 else 591 plt_offset += plt_header_size; 592 } 593 594 /* 595 * x86 doesn't insert IFUNC relocations in .plt order, so sort to get 596 * back in order. 597 */ 598 if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri)) 599 goto out_elf_end; 600 601 for (idx = 0; idx < ri.nr_entries; idx++) { 602 const char *elf_name = NULL; 603 char *demangled = NULL; 604 605 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym); 606 607 elf_name = elf_sym__name(&sym, symstrs); 608 demangled = demangle_sym(dso, 0, elf_name); 609 if (demangled) 610 elf_name = demangled; 611 if (*elf_name) 612 snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name); 613 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname))) 614 snprintf(sympltname, sizeof(sympltname), 615 "offset_%#" PRIx64 "@plt", plt_offset); 616 free(demangled); 617 618 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname); 619 if (!f) 620 goto out_elf_end; 621 622 plt_offset += plt_entry_size; 623 symbols__insert(&dso->symbols, f); 624 ++nr; 625 } 626 627 err = 0; 628 out_elf_end: 629 exit_rel(&ri); 630 if (err == 0) 631 return nr; 632 pr_debug("%s: problems reading %s PLT info.\n", 633 __func__, dso->long_name); 634 return 0; 635 } 636 637 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) 638 { 639 return demangle_sym(dso, kmodule, elf_name); 640 } 641 642 /* 643 * Align offset to 4 bytes as needed for note name and descriptor data. 644 */ 645 #define NOTE_ALIGN(n) (((n) + 3) & -4U) 646 647 static int elf_read_build_id(Elf *elf, void *bf, size_t size) 648 { 649 int err = -1; 650 GElf_Ehdr ehdr; 651 GElf_Shdr shdr; 652 Elf_Data *data; 653 Elf_Scn *sec; 654 Elf_Kind ek; 655 void *ptr; 656 657 if (size < BUILD_ID_SIZE) 658 goto out; 659 660 ek = elf_kind(elf); 661 if (ek != ELF_K_ELF) 662 goto out; 663 664 if (gelf_getehdr(elf, &ehdr) == NULL) { 665 pr_err("%s: cannot get elf header.\n", __func__); 666 goto out; 667 } 668 669 /* 670 * Check following sections for notes: 671 * '.note.gnu.build-id' 672 * '.notes' 673 * '.note' (VDSO specific) 674 */ 675 do { 676 sec = elf_section_by_name(elf, &ehdr, &shdr, 677 ".note.gnu.build-id", NULL); 678 if (sec) 679 break; 680 681 sec = elf_section_by_name(elf, &ehdr, &shdr, 682 ".notes", NULL); 683 if (sec) 684 break; 685 686 sec = elf_section_by_name(elf, &ehdr, &shdr, 687 ".note", NULL); 688 if (sec) 689 break; 690 691 return err; 692 693 } while (0); 694 695 data = elf_getdata(sec, NULL); 696 if (data == NULL) 697 goto out; 698 699 ptr = data->d_buf; 700 while (ptr < (data->d_buf + data->d_size)) { 701 GElf_Nhdr *nhdr = ptr; 702 size_t namesz = NOTE_ALIGN(nhdr->n_namesz), 703 descsz = NOTE_ALIGN(nhdr->n_descsz); 704 const char *name; 705 706 ptr += sizeof(*nhdr); 707 name = ptr; 708 ptr += namesz; 709 if (nhdr->n_type == NT_GNU_BUILD_ID && 710 nhdr->n_namesz == sizeof("GNU")) { 711 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 712 size_t sz = min(size, descsz); 713 memcpy(bf, ptr, sz); 714 memset(bf + sz, 0, size - sz); 715 err = descsz; 716 break; 717 } 718 } 719 ptr += descsz; 720 } 721 722 out: 723 return err; 724 } 725 726 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT 727 728 static int read_build_id(const char *filename, struct build_id *bid) 729 { 730 size_t size = sizeof(bid->data); 731 int err = -1; 732 bfd *abfd; 733 734 abfd = bfd_openr(filename, NULL); 735 if (!abfd) 736 return -1; 737 738 if (!bfd_check_format(abfd, bfd_object)) { 739 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 740 goto out_close; 741 } 742 743 if (!abfd->build_id || abfd->build_id->size > size) 744 goto out_close; 745 746 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size); 747 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size); 748 err = bid->size = abfd->build_id->size; 749 750 out_close: 751 bfd_close(abfd); 752 return err; 753 } 754 755 #else // HAVE_LIBBFD_BUILDID_SUPPORT 756 757 static int read_build_id(const char *filename, struct build_id *bid) 758 { 759 size_t size = sizeof(bid->data); 760 int fd, err = -1; 761 Elf *elf; 762 763 if (size < BUILD_ID_SIZE) 764 goto out; 765 766 fd = open(filename, O_RDONLY); 767 if (fd < 0) 768 goto out; 769 770 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 771 if (elf == NULL) { 772 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 773 goto out_close; 774 } 775 776 err = elf_read_build_id(elf, bid->data, size); 777 if (err > 0) 778 bid->size = err; 779 780 elf_end(elf); 781 out_close: 782 close(fd); 783 out: 784 return err; 785 } 786 787 #endif // HAVE_LIBBFD_BUILDID_SUPPORT 788 789 int filename__read_build_id(const char *filename, struct build_id *bid) 790 { 791 struct kmod_path m = { .name = NULL, }; 792 char path[PATH_MAX]; 793 int err; 794 795 if (!filename) 796 return -EFAULT; 797 798 err = kmod_path__parse(&m, filename); 799 if (err) 800 return -1; 801 802 if (m.comp) { 803 int error = 0, fd; 804 805 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error); 806 if (fd < 0) { 807 pr_debug("Failed to decompress (error %d) %s\n", 808 error, filename); 809 return -1; 810 } 811 close(fd); 812 filename = path; 813 } 814 815 err = read_build_id(filename, bid); 816 817 if (m.comp) 818 unlink(filename); 819 return err; 820 } 821 822 int sysfs__read_build_id(const char *filename, struct build_id *bid) 823 { 824 size_t size = sizeof(bid->data); 825 int fd, err = -1; 826 827 fd = open(filename, O_RDONLY); 828 if (fd < 0) 829 goto out; 830 831 while (1) { 832 char bf[BUFSIZ]; 833 GElf_Nhdr nhdr; 834 size_t namesz, descsz; 835 836 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) 837 break; 838 839 namesz = NOTE_ALIGN(nhdr.n_namesz); 840 descsz = NOTE_ALIGN(nhdr.n_descsz); 841 if (nhdr.n_type == NT_GNU_BUILD_ID && 842 nhdr.n_namesz == sizeof("GNU")) { 843 if (read(fd, bf, namesz) != (ssize_t)namesz) 844 break; 845 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { 846 size_t sz = min(descsz, size); 847 if (read(fd, bid->data, sz) == (ssize_t)sz) { 848 memset(bid->data + sz, 0, size - sz); 849 bid->size = sz; 850 err = 0; 851 break; 852 } 853 } else if (read(fd, bf, descsz) != (ssize_t)descsz) 854 break; 855 } else { 856 int n = namesz + descsz; 857 858 if (n > (int)sizeof(bf)) { 859 n = sizeof(bf); 860 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", 861 __func__, filename, nhdr.n_namesz, nhdr.n_descsz); 862 } 863 if (read(fd, bf, n) != n) 864 break; 865 } 866 } 867 close(fd); 868 out: 869 return err; 870 } 871 872 #ifdef HAVE_LIBBFD_SUPPORT 873 874 int filename__read_debuglink(const char *filename, char *debuglink, 875 size_t size) 876 { 877 int err = -1; 878 asection *section; 879 bfd *abfd; 880 881 abfd = bfd_openr(filename, NULL); 882 if (!abfd) 883 return -1; 884 885 if (!bfd_check_format(abfd, bfd_object)) { 886 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); 887 goto out_close; 888 } 889 890 section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); 891 if (!section) 892 goto out_close; 893 894 if (section->size > size) 895 goto out_close; 896 897 if (!bfd_get_section_contents(abfd, section, debuglink, 0, 898 section->size)) 899 goto out_close; 900 901 err = 0; 902 903 out_close: 904 bfd_close(abfd); 905 return err; 906 } 907 908 #else 909 910 int filename__read_debuglink(const char *filename, char *debuglink, 911 size_t size) 912 { 913 int fd, err = -1; 914 Elf *elf; 915 GElf_Ehdr ehdr; 916 GElf_Shdr shdr; 917 Elf_Data *data; 918 Elf_Scn *sec; 919 Elf_Kind ek; 920 921 fd = open(filename, O_RDONLY); 922 if (fd < 0) 923 goto out; 924 925 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 926 if (elf == NULL) { 927 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); 928 goto out_close; 929 } 930 931 ek = elf_kind(elf); 932 if (ek != ELF_K_ELF) 933 goto out_elf_end; 934 935 if (gelf_getehdr(elf, &ehdr) == NULL) { 936 pr_err("%s: cannot get elf header.\n", __func__); 937 goto out_elf_end; 938 } 939 940 sec = elf_section_by_name(elf, &ehdr, &shdr, 941 ".gnu_debuglink", NULL); 942 if (sec == NULL) 943 goto out_elf_end; 944 945 data = elf_getdata(sec, NULL); 946 if (data == NULL) 947 goto out_elf_end; 948 949 /* the start of this section is a zero-terminated string */ 950 strncpy(debuglink, data->d_buf, size); 951 952 err = 0; 953 954 out_elf_end: 955 elf_end(elf); 956 out_close: 957 close(fd); 958 out: 959 return err; 960 } 961 962 #endif 963 964 static int dso__swap_init(struct dso *dso, unsigned char eidata) 965 { 966 static unsigned int const endian = 1; 967 968 dso->needs_swap = DSO_SWAP__NO; 969 970 switch (eidata) { 971 case ELFDATA2LSB: 972 /* We are big endian, DSO is little endian. */ 973 if (*(unsigned char const *)&endian != 1) 974 dso->needs_swap = DSO_SWAP__YES; 975 break; 976 977 case ELFDATA2MSB: 978 /* We are little endian, DSO is big endian. */ 979 if (*(unsigned char const *)&endian != 0) 980 dso->needs_swap = DSO_SWAP__YES; 981 break; 982 983 default: 984 pr_err("unrecognized DSO data encoding %d\n", eidata); 985 return -EINVAL; 986 } 987 988 return 0; 989 } 990 991 bool symsrc__possibly_runtime(struct symsrc *ss) 992 { 993 return ss->dynsym || ss->opdsec; 994 } 995 996 bool symsrc__has_symtab(struct symsrc *ss) 997 { 998 return ss->symtab != NULL; 999 } 1000 1001 void symsrc__destroy(struct symsrc *ss) 1002 { 1003 zfree(&ss->name); 1004 elf_end(ss->elf); 1005 close(ss->fd); 1006 } 1007 1008 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) 1009 { 1010 /* 1011 * Usually vmlinux is an ELF file with type ET_EXEC for most 1012 * architectures; except Arm64 kernel is linked with option 1013 * '-share', so need to check type ET_DYN. 1014 */ 1015 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL || 1016 ehdr.e_type == ET_DYN; 1017 } 1018 1019 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 1020 enum dso_binary_type type) 1021 { 1022 GElf_Ehdr ehdr; 1023 Elf *elf; 1024 int fd; 1025 1026 if (dso__needs_decompress(dso)) { 1027 fd = dso__decompress_kmodule_fd(dso, name); 1028 if (fd < 0) 1029 return -1; 1030 1031 type = dso->symtab_type; 1032 } else { 1033 fd = open(name, O_RDONLY); 1034 if (fd < 0) { 1035 dso->load_errno = errno; 1036 return -1; 1037 } 1038 } 1039 1040 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1041 if (elf == NULL) { 1042 pr_debug("%s: cannot read %s ELF file.\n", __func__, name); 1043 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 1044 goto out_close; 1045 } 1046 1047 if (gelf_getehdr(elf, &ehdr) == NULL) { 1048 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; 1049 pr_debug("%s: cannot get elf header.\n", __func__); 1050 goto out_elf_end; 1051 } 1052 1053 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { 1054 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR; 1055 goto out_elf_end; 1056 } 1057 1058 /* Always reject images with a mismatched build-id: */ 1059 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) { 1060 u8 build_id[BUILD_ID_SIZE]; 1061 struct build_id bid; 1062 int size; 1063 1064 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE); 1065 if (size <= 0) { 1066 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; 1067 goto out_elf_end; 1068 } 1069 1070 build_id__init(&bid, build_id, size); 1071 if (!dso__build_id_equal(dso, &bid)) { 1072 pr_debug("%s: build id mismatch for %s.\n", __func__, name); 1073 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; 1074 goto out_elf_end; 1075 } 1076 } 1077 1078 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1079 1080 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", 1081 NULL); 1082 if (ss->symshdr.sh_type != SHT_SYMTAB) 1083 ss->symtab = NULL; 1084 1085 ss->dynsym_idx = 0; 1086 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", 1087 &ss->dynsym_idx); 1088 if (ss->dynshdr.sh_type != SHT_DYNSYM) 1089 ss->dynsym = NULL; 1090 1091 ss->opdidx = 0; 1092 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", 1093 &ss->opdidx); 1094 if (ss->opdshdr.sh_type != SHT_PROGBITS) 1095 ss->opdsec = NULL; 1096 1097 if (dso->kernel == DSO_SPACE__USER) 1098 ss->adjust_symbols = true; 1099 else 1100 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); 1101 1102 ss->name = strdup(name); 1103 if (!ss->name) { 1104 dso->load_errno = errno; 1105 goto out_elf_end; 1106 } 1107 1108 ss->elf = elf; 1109 ss->fd = fd; 1110 ss->ehdr = ehdr; 1111 ss->type = type; 1112 1113 return 0; 1114 1115 out_elf_end: 1116 elf_end(elf); 1117 out_close: 1118 close(fd); 1119 return -1; 1120 } 1121 1122 /** 1123 * ref_reloc_sym_not_found - has kernel relocation symbol been found. 1124 * @kmap: kernel maps and relocation reference symbol 1125 * 1126 * This function returns %true if we are dealing with the kernel maps and the 1127 * relocation reference symbol has not yet been found. Otherwise %false is 1128 * returned. 1129 */ 1130 static bool ref_reloc_sym_not_found(struct kmap *kmap) 1131 { 1132 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && 1133 !kmap->ref_reloc_sym->unrelocated_addr; 1134 } 1135 1136 /** 1137 * ref_reloc - kernel relocation offset. 1138 * @kmap: kernel maps and relocation reference symbol 1139 * 1140 * This function returns the offset of kernel addresses as determined by using 1141 * the relocation reference symbol i.e. if the kernel has not been relocated 1142 * then the return value is zero. 1143 */ 1144 static u64 ref_reloc(struct kmap *kmap) 1145 { 1146 if (kmap && kmap->ref_reloc_sym && 1147 kmap->ref_reloc_sym->unrelocated_addr) 1148 return kmap->ref_reloc_sym->addr - 1149 kmap->ref_reloc_sym->unrelocated_addr; 1150 return 0; 1151 } 1152 1153 void __weak arch__sym_update(struct symbol *s __maybe_unused, 1154 GElf_Sym *sym __maybe_unused) { } 1155 1156 static int dso__process_kernel_symbol(struct dso *dso, struct map *map, 1157 GElf_Sym *sym, GElf_Shdr *shdr, 1158 struct maps *kmaps, struct kmap *kmap, 1159 struct dso **curr_dsop, struct map **curr_mapp, 1160 const char *section_name, 1161 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) 1162 { 1163 struct dso *curr_dso = *curr_dsop; 1164 struct map *curr_map; 1165 char dso_name[PATH_MAX]; 1166 1167 /* Adjust symbol to map to file offset */ 1168 if (adjust_kernel_syms) 1169 sym->st_value -= shdr->sh_addr - shdr->sh_offset; 1170 1171 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0) 1172 return 0; 1173 1174 if (strcmp(section_name, ".text") == 0) { 1175 /* 1176 * The initial kernel mapping is based on 1177 * kallsyms and identity maps. Overwrite it to 1178 * map to the kernel dso. 1179 */ 1180 if (*remap_kernel && dso->kernel && !kmodule) { 1181 *remap_kernel = false; 1182 map->start = shdr->sh_addr + ref_reloc(kmap); 1183 map->end = map->start + shdr->sh_size; 1184 map->pgoff = shdr->sh_offset; 1185 map->map_ip = map__map_ip; 1186 map->unmap_ip = map__unmap_ip; 1187 /* Ensure maps are correctly ordered */ 1188 if (kmaps) { 1189 map__get(map); 1190 maps__remove(kmaps, map); 1191 maps__insert(kmaps, map); 1192 map__put(map); 1193 } 1194 } 1195 1196 /* 1197 * The initial module mapping is based on 1198 * /proc/modules mapped to offset zero. 1199 * Overwrite it to map to the module dso. 1200 */ 1201 if (*remap_kernel && kmodule) { 1202 *remap_kernel = false; 1203 map->pgoff = shdr->sh_offset; 1204 } 1205 1206 *curr_mapp = map; 1207 *curr_dsop = dso; 1208 return 0; 1209 } 1210 1211 if (!kmap) 1212 return 0; 1213 1214 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); 1215 1216 curr_map = maps__find_by_name(kmaps, dso_name); 1217 if (curr_map == NULL) { 1218 u64 start = sym->st_value; 1219 1220 if (kmodule) 1221 start += map->start + shdr->sh_offset; 1222 1223 curr_dso = dso__new(dso_name); 1224 if (curr_dso == NULL) 1225 return -1; 1226 curr_dso->kernel = dso->kernel; 1227 curr_dso->long_name = dso->long_name; 1228 curr_dso->long_name_len = dso->long_name_len; 1229 curr_map = map__new2(start, curr_dso); 1230 dso__put(curr_dso); 1231 if (curr_map == NULL) 1232 return -1; 1233 1234 if (curr_dso->kernel) 1235 map__kmap(curr_map)->kmaps = kmaps; 1236 1237 if (adjust_kernel_syms) { 1238 curr_map->start = shdr->sh_addr + ref_reloc(kmap); 1239 curr_map->end = curr_map->start + shdr->sh_size; 1240 curr_map->pgoff = shdr->sh_offset; 1241 } else { 1242 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; 1243 } 1244 curr_dso->symtab_type = dso->symtab_type; 1245 maps__insert(kmaps, curr_map); 1246 /* 1247 * Add it before we drop the reference to curr_map, i.e. while 1248 * we still are sure to have a reference to this DSO via 1249 * *curr_map->dso. 1250 */ 1251 dsos__add(&kmaps->machine->dsos, curr_dso); 1252 /* kmaps already got it */ 1253 map__put(curr_map); 1254 dso__set_loaded(curr_dso); 1255 *curr_mapp = curr_map; 1256 *curr_dsop = curr_dso; 1257 } else 1258 *curr_dsop = curr_map->dso; 1259 1260 return 0; 1261 } 1262 1263 static int 1264 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1265 struct symsrc *runtime_ss, int kmodule, int dynsym) 1266 { 1267 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; 1268 struct maps *kmaps = kmap ? map__kmaps(map) : NULL; 1269 struct map *curr_map = map; 1270 struct dso *curr_dso = dso; 1271 Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym; 1272 uint32_t nr_syms; 1273 int err = -1; 1274 uint32_t idx; 1275 GElf_Ehdr ehdr; 1276 GElf_Shdr shdr; 1277 GElf_Shdr tshdr; 1278 Elf_Data *syms, *opddata = NULL; 1279 GElf_Sym sym; 1280 Elf_Scn *sec, *sec_strndx; 1281 Elf *elf; 1282 int nr = 0; 1283 bool remap_kernel = false, adjust_kernel_syms = false; 1284 1285 if (kmap && !kmaps) 1286 return -1; 1287 1288 elf = syms_ss->elf; 1289 ehdr = syms_ss->ehdr; 1290 if (dynsym) { 1291 sec = syms_ss->dynsym; 1292 shdr = syms_ss->dynshdr; 1293 } else { 1294 sec = syms_ss->symtab; 1295 shdr = syms_ss->symshdr; 1296 } 1297 1298 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, 1299 ".text", NULL)) 1300 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; 1301 1302 if (runtime_ss->opdsec) 1303 opddata = elf_rawdata(runtime_ss->opdsec, NULL); 1304 1305 syms = elf_getdata(sec, NULL); 1306 if (syms == NULL) 1307 goto out_elf_end; 1308 1309 sec = elf_getscn(elf, shdr.sh_link); 1310 if (sec == NULL) 1311 goto out_elf_end; 1312 1313 symstrs = elf_getdata(sec, NULL); 1314 if (symstrs == NULL) 1315 goto out_elf_end; 1316 1317 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); 1318 if (sec_strndx == NULL) 1319 goto out_elf_end; 1320 1321 secstrs_run = elf_getdata(sec_strndx, NULL); 1322 if (secstrs_run == NULL) 1323 goto out_elf_end; 1324 1325 sec_strndx = elf_getscn(elf, ehdr.e_shstrndx); 1326 if (sec_strndx == NULL) 1327 goto out_elf_end; 1328 1329 secstrs_sym = elf_getdata(sec_strndx, NULL); 1330 if (secstrs_sym == NULL) 1331 goto out_elf_end; 1332 1333 nr_syms = shdr.sh_size / shdr.sh_entsize; 1334 1335 memset(&sym, 0, sizeof(sym)); 1336 1337 /* 1338 * The kernel relocation symbol is needed in advance in order to adjust 1339 * kernel maps correctly. 1340 */ 1341 if (ref_reloc_sym_not_found(kmap)) { 1342 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1343 const char *elf_name = elf_sym__name(&sym, symstrs); 1344 1345 if (strcmp(elf_name, kmap->ref_reloc_sym->name)) 1346 continue; 1347 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; 1348 map->reloc = kmap->ref_reloc_sym->addr - 1349 kmap->ref_reloc_sym->unrelocated_addr; 1350 break; 1351 } 1352 } 1353 1354 /* 1355 * Handle any relocation of vdso necessary because older kernels 1356 * attempted to prelink vdso to its virtual address. 1357 */ 1358 if (dso__is_vdso(dso)) 1359 map->reloc = map->start - dso->text_offset; 1360 1361 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); 1362 /* 1363 * Initial kernel and module mappings do not map to the dso. 1364 * Flag the fixups. 1365 */ 1366 if (dso->kernel) { 1367 remap_kernel = true; 1368 adjust_kernel_syms = dso->adjust_symbols; 1369 } 1370 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { 1371 struct symbol *f; 1372 const char *elf_name = elf_sym__name(&sym, symstrs); 1373 char *demangled = NULL; 1374 int is_label = elf_sym__is_label(&sym); 1375 const char *section_name; 1376 bool used_opd = false; 1377 1378 if (!is_label && !elf_sym__filter(&sym)) 1379 continue; 1380 1381 /* Reject ARM ELF "mapping symbols": these aren't unique and 1382 * don't identify functions, so will confuse the profile 1383 * output: */ 1384 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { 1385 if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) 1386 && (elf_name[2] == '\0' || elf_name[2] == '.')) 1387 continue; 1388 } 1389 1390 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { 1391 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; 1392 u64 *opd = opddata->d_buf + offset; 1393 sym.st_value = DSO__SWAP(dso, u64, *opd); 1394 sym.st_shndx = elf_addr_to_index(runtime_ss->elf, 1395 sym.st_value); 1396 used_opd = true; 1397 } 1398 1399 /* 1400 * When loading symbols in a data mapping, ABS symbols (which 1401 * has a value of SHN_ABS in its st_shndx) failed at 1402 * elf_getscn(). And it marks the loading as a failure so 1403 * already loaded symbols cannot be fixed up. 1404 * 1405 * I'm not sure what should be done. Just ignore them for now. 1406 * - Namhyung Kim 1407 */ 1408 if (sym.st_shndx == SHN_ABS) 1409 continue; 1410 1411 sec = elf_getscn(syms_ss->elf, sym.st_shndx); 1412 if (!sec) 1413 goto out_elf_end; 1414 1415 gelf_getshdr(sec, &shdr); 1416 1417 /* 1418 * If the attribute bit SHF_ALLOC is not set, the section 1419 * doesn't occupy memory during process execution. 1420 * E.g. ".gnu.warning.*" section is used by linker to generate 1421 * warnings when calling deprecated functions, the symbols in 1422 * the section aren't loaded to memory during process execution, 1423 * so skip them. 1424 */ 1425 if (!(shdr.sh_flags & SHF_ALLOC)) 1426 continue; 1427 1428 secstrs = secstrs_sym; 1429 1430 /* 1431 * We have to fallback to runtime when syms' section header has 1432 * NOBITS set. NOBITS results in file offset (sh_offset) not 1433 * being incremented. So sh_offset used below has different 1434 * values for syms (invalid) and runtime (valid). 1435 */ 1436 if (shdr.sh_type == SHT_NOBITS) { 1437 sec = elf_getscn(runtime_ss->elf, sym.st_shndx); 1438 if (!sec) 1439 goto out_elf_end; 1440 1441 gelf_getshdr(sec, &shdr); 1442 secstrs = secstrs_run; 1443 } 1444 1445 if (is_label && !elf_sec__filter(&shdr, secstrs)) 1446 continue; 1447 1448 section_name = elf_sec__name(&shdr, secstrs); 1449 1450 /* On ARM, symbols for thumb functions have 1 added to 1451 * the symbol address as a flag - remove it */ 1452 if ((ehdr.e_machine == EM_ARM) && 1453 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && 1454 (sym.st_value & 1)) 1455 --sym.st_value; 1456 1457 if (dso->kernel) { 1458 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, 1459 section_name, adjust_kernel_syms, kmodule, &remap_kernel)) 1460 goto out_elf_end; 1461 } else if ((used_opd && runtime_ss->adjust_symbols) || 1462 (!used_opd && syms_ss->adjust_symbols)) { 1463 GElf_Phdr phdr; 1464 1465 if (elf_read_program_header(runtime_ss->elf, 1466 (u64)sym.st_value, &phdr)) { 1467 pr_debug4("%s: failed to find program header for " 1468 "symbol: %s st_value: %#" PRIx64 "\n", 1469 __func__, elf_name, (u64)sym.st_value); 1470 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1471 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", 1472 __func__, (u64)sym.st_value, (u64)shdr.sh_addr, 1473 (u64)shdr.sh_offset); 1474 /* 1475 * Fail to find program header, let's rollback 1476 * to use shdr.sh_addr and shdr.sh_offset to 1477 * calibrate symbol's file address, though this 1478 * is not necessary for normal C ELF file, we 1479 * still need to handle java JIT symbols in this 1480 * case. 1481 */ 1482 sym.st_value -= shdr.sh_addr - shdr.sh_offset; 1483 } else { 1484 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " 1485 "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n", 1486 __func__, (u64)sym.st_value, (u64)phdr.p_vaddr, 1487 (u64)phdr.p_offset); 1488 sym.st_value -= phdr.p_vaddr - phdr.p_offset; 1489 } 1490 } 1491 1492 demangled = demangle_sym(dso, kmodule, elf_name); 1493 if (demangled != NULL) 1494 elf_name = demangled; 1495 1496 f = symbol__new(sym.st_value, sym.st_size, 1497 GELF_ST_BIND(sym.st_info), 1498 GELF_ST_TYPE(sym.st_info), elf_name); 1499 free(demangled); 1500 if (!f) 1501 goto out_elf_end; 1502 1503 arch__sym_update(f, &sym); 1504 1505 __symbols__insert(&curr_dso->symbols, f, dso->kernel); 1506 nr++; 1507 } 1508 1509 /* 1510 * For misannotated, zeroed, ASM function sizes. 1511 */ 1512 if (nr > 0) { 1513 symbols__fixup_end(&dso->symbols, false); 1514 symbols__fixup_duplicate(&dso->symbols); 1515 if (kmap) { 1516 /* 1517 * We need to fixup this here too because we create new 1518 * maps here, for things like vsyscall sections. 1519 */ 1520 maps__fixup_end(kmaps); 1521 } 1522 } 1523 err = nr; 1524 out_elf_end: 1525 return err; 1526 } 1527 1528 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, 1529 struct symsrc *runtime_ss, int kmodule) 1530 { 1531 int nr = 0; 1532 int err = -1; 1533 1534 dso->symtab_type = syms_ss->type; 1535 dso->is_64_bit = syms_ss->is_64_bit; 1536 dso->rel = syms_ss->ehdr.e_type == ET_REL; 1537 1538 /* 1539 * Modules may already have symbols from kallsyms, but those symbols 1540 * have the wrong values for the dso maps, so remove them. 1541 */ 1542 if (kmodule && syms_ss->symtab) 1543 symbols__delete(&dso->symbols); 1544 1545 if (!syms_ss->symtab) { 1546 /* 1547 * If the vmlinux is stripped, fail so we will fall back 1548 * to using kallsyms. The vmlinux runtime symbols aren't 1549 * of much use. 1550 */ 1551 if (dso->kernel) 1552 return err; 1553 } else { 1554 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, 1555 kmodule, 0); 1556 if (err < 0) 1557 return err; 1558 nr = err; 1559 } 1560 1561 if (syms_ss->dynsym) { 1562 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, 1563 kmodule, 1); 1564 if (err < 0) 1565 return err; 1566 err += nr; 1567 } 1568 1569 return err; 1570 } 1571 1572 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) 1573 { 1574 GElf_Phdr phdr; 1575 size_t i, phdrnum; 1576 int err; 1577 u64 sz; 1578 1579 if (elf_getphdrnum(elf, &phdrnum)) 1580 return -1; 1581 1582 for (i = 0; i < phdrnum; i++) { 1583 if (gelf_getphdr(elf, i, &phdr) == NULL) 1584 return -1; 1585 if (phdr.p_type != PT_LOAD) 1586 continue; 1587 if (exe) { 1588 if (!(phdr.p_flags & PF_X)) 1589 continue; 1590 } else { 1591 if (!(phdr.p_flags & PF_R)) 1592 continue; 1593 } 1594 sz = min(phdr.p_memsz, phdr.p_filesz); 1595 if (!sz) 1596 continue; 1597 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); 1598 if (err) 1599 return err; 1600 } 1601 return 0; 1602 } 1603 1604 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, 1605 bool *is_64_bit) 1606 { 1607 int err; 1608 Elf *elf; 1609 1610 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1611 if (elf == NULL) 1612 return -1; 1613 1614 if (is_64_bit) 1615 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); 1616 1617 err = elf_read_maps(elf, exe, mapfn, data); 1618 1619 elf_end(elf); 1620 return err; 1621 } 1622 1623 enum dso_type dso__type_fd(int fd) 1624 { 1625 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 1626 GElf_Ehdr ehdr; 1627 Elf_Kind ek; 1628 Elf *elf; 1629 1630 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 1631 if (elf == NULL) 1632 goto out; 1633 1634 ek = elf_kind(elf); 1635 if (ek != ELF_K_ELF) 1636 goto out_end; 1637 1638 if (gelf_getclass(elf) == ELFCLASS64) { 1639 dso_type = DSO__TYPE_64BIT; 1640 goto out_end; 1641 } 1642 1643 if (gelf_getehdr(elf, &ehdr) == NULL) 1644 goto out_end; 1645 1646 if (ehdr.e_machine == EM_X86_64) 1647 dso_type = DSO__TYPE_X32BIT; 1648 else 1649 dso_type = DSO__TYPE_32BIT; 1650 out_end: 1651 elf_end(elf); 1652 out: 1653 return dso_type; 1654 } 1655 1656 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) 1657 { 1658 ssize_t r; 1659 size_t n; 1660 int err = -1; 1661 char *buf = malloc(page_size); 1662 1663 if (buf == NULL) 1664 return -1; 1665 1666 if (lseek(to, to_offs, SEEK_SET) != to_offs) 1667 goto out; 1668 1669 if (lseek(from, from_offs, SEEK_SET) != from_offs) 1670 goto out; 1671 1672 while (len) { 1673 n = page_size; 1674 if (len < n) 1675 n = len; 1676 /* Use read because mmap won't work on proc files */ 1677 r = read(from, buf, n); 1678 if (r < 0) 1679 goto out; 1680 if (!r) 1681 break; 1682 n = r; 1683 r = write(to, buf, n); 1684 if (r < 0) 1685 goto out; 1686 if ((size_t)r != n) 1687 goto out; 1688 len -= n; 1689 } 1690 1691 err = 0; 1692 out: 1693 free(buf); 1694 return err; 1695 } 1696 1697 struct kcore { 1698 int fd; 1699 int elfclass; 1700 Elf *elf; 1701 GElf_Ehdr ehdr; 1702 }; 1703 1704 static int kcore__open(struct kcore *kcore, const char *filename) 1705 { 1706 GElf_Ehdr *ehdr; 1707 1708 kcore->fd = open(filename, O_RDONLY); 1709 if (kcore->fd == -1) 1710 return -1; 1711 1712 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); 1713 if (!kcore->elf) 1714 goto out_close; 1715 1716 kcore->elfclass = gelf_getclass(kcore->elf); 1717 if (kcore->elfclass == ELFCLASSNONE) 1718 goto out_end; 1719 1720 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); 1721 if (!ehdr) 1722 goto out_end; 1723 1724 return 0; 1725 1726 out_end: 1727 elf_end(kcore->elf); 1728 out_close: 1729 close(kcore->fd); 1730 return -1; 1731 } 1732 1733 static int kcore__init(struct kcore *kcore, char *filename, int elfclass, 1734 bool temp) 1735 { 1736 kcore->elfclass = elfclass; 1737 1738 if (temp) 1739 kcore->fd = mkstemp(filename); 1740 else 1741 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); 1742 if (kcore->fd == -1) 1743 return -1; 1744 1745 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); 1746 if (!kcore->elf) 1747 goto out_close; 1748 1749 if (!gelf_newehdr(kcore->elf, elfclass)) 1750 goto out_end; 1751 1752 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); 1753 1754 return 0; 1755 1756 out_end: 1757 elf_end(kcore->elf); 1758 out_close: 1759 close(kcore->fd); 1760 unlink(filename); 1761 return -1; 1762 } 1763 1764 static void kcore__close(struct kcore *kcore) 1765 { 1766 elf_end(kcore->elf); 1767 close(kcore->fd); 1768 } 1769 1770 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) 1771 { 1772 GElf_Ehdr *ehdr = &to->ehdr; 1773 GElf_Ehdr *kehdr = &from->ehdr; 1774 1775 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); 1776 ehdr->e_type = kehdr->e_type; 1777 ehdr->e_machine = kehdr->e_machine; 1778 ehdr->e_version = kehdr->e_version; 1779 ehdr->e_entry = 0; 1780 ehdr->e_shoff = 0; 1781 ehdr->e_flags = kehdr->e_flags; 1782 ehdr->e_phnum = count; 1783 ehdr->e_shentsize = 0; 1784 ehdr->e_shnum = 0; 1785 ehdr->e_shstrndx = 0; 1786 1787 if (from->elfclass == ELFCLASS32) { 1788 ehdr->e_phoff = sizeof(Elf32_Ehdr); 1789 ehdr->e_ehsize = sizeof(Elf32_Ehdr); 1790 ehdr->e_phentsize = sizeof(Elf32_Phdr); 1791 } else { 1792 ehdr->e_phoff = sizeof(Elf64_Ehdr); 1793 ehdr->e_ehsize = sizeof(Elf64_Ehdr); 1794 ehdr->e_phentsize = sizeof(Elf64_Phdr); 1795 } 1796 1797 if (!gelf_update_ehdr(to->elf, ehdr)) 1798 return -1; 1799 1800 if (!gelf_newphdr(to->elf, count)) 1801 return -1; 1802 1803 return 0; 1804 } 1805 1806 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, 1807 u64 addr, u64 len) 1808 { 1809 GElf_Phdr phdr = { 1810 .p_type = PT_LOAD, 1811 .p_flags = PF_R | PF_W | PF_X, 1812 .p_offset = offset, 1813 .p_vaddr = addr, 1814 .p_paddr = 0, 1815 .p_filesz = len, 1816 .p_memsz = len, 1817 .p_align = page_size, 1818 }; 1819 1820 if (!gelf_update_phdr(kcore->elf, idx, &phdr)) 1821 return -1; 1822 1823 return 0; 1824 } 1825 1826 static off_t kcore__write(struct kcore *kcore) 1827 { 1828 return elf_update(kcore->elf, ELF_C_WRITE); 1829 } 1830 1831 struct phdr_data { 1832 off_t offset; 1833 off_t rel; 1834 u64 addr; 1835 u64 len; 1836 struct list_head node; 1837 struct phdr_data *remaps; 1838 }; 1839 1840 struct sym_data { 1841 u64 addr; 1842 struct list_head node; 1843 }; 1844 1845 struct kcore_copy_info { 1846 u64 stext; 1847 u64 etext; 1848 u64 first_symbol; 1849 u64 last_symbol; 1850 u64 first_module; 1851 u64 first_module_symbol; 1852 u64 last_module_symbol; 1853 size_t phnum; 1854 struct list_head phdrs; 1855 struct list_head syms; 1856 }; 1857 1858 #define kcore_copy__for_each_phdr(k, p) \ 1859 list_for_each_entry((p), &(k)->phdrs, node) 1860 1861 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset) 1862 { 1863 struct phdr_data *p = zalloc(sizeof(*p)); 1864 1865 if (p) { 1866 p->addr = addr; 1867 p->len = len; 1868 p->offset = offset; 1869 } 1870 1871 return p; 1872 } 1873 1874 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci, 1875 u64 addr, u64 len, 1876 off_t offset) 1877 { 1878 struct phdr_data *p = phdr_data__new(addr, len, offset); 1879 1880 if (p) 1881 list_add_tail(&p->node, &kci->phdrs); 1882 1883 return p; 1884 } 1885 1886 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci) 1887 { 1888 struct phdr_data *p, *tmp; 1889 1890 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) { 1891 list_del_init(&p->node); 1892 free(p); 1893 } 1894 } 1895 1896 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci, 1897 u64 addr) 1898 { 1899 struct sym_data *s = zalloc(sizeof(*s)); 1900 1901 if (s) { 1902 s->addr = addr; 1903 list_add_tail(&s->node, &kci->syms); 1904 } 1905 1906 return s; 1907 } 1908 1909 static void kcore_copy__free_syms(struct kcore_copy_info *kci) 1910 { 1911 struct sym_data *s, *tmp; 1912 1913 list_for_each_entry_safe(s, tmp, &kci->syms, node) { 1914 list_del_init(&s->node); 1915 free(s); 1916 } 1917 } 1918 1919 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, 1920 u64 start) 1921 { 1922 struct kcore_copy_info *kci = arg; 1923 1924 if (!kallsyms__is_function(type)) 1925 return 0; 1926 1927 if (strchr(name, '[')) { 1928 if (!kci->first_module_symbol || start < kci->first_module_symbol) 1929 kci->first_module_symbol = start; 1930 if (start > kci->last_module_symbol) 1931 kci->last_module_symbol = start; 1932 return 0; 1933 } 1934 1935 if (!kci->first_symbol || start < kci->first_symbol) 1936 kci->first_symbol = start; 1937 1938 if (!kci->last_symbol || start > kci->last_symbol) 1939 kci->last_symbol = start; 1940 1941 if (!strcmp(name, "_stext")) { 1942 kci->stext = start; 1943 return 0; 1944 } 1945 1946 if (!strcmp(name, "_etext")) { 1947 kci->etext = start; 1948 return 0; 1949 } 1950 1951 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start)) 1952 return -1; 1953 1954 return 0; 1955 } 1956 1957 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, 1958 const char *dir) 1959 { 1960 char kallsyms_filename[PATH_MAX]; 1961 1962 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); 1963 1964 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) 1965 return -1; 1966 1967 if (kallsyms__parse(kallsyms_filename, kci, 1968 kcore_copy__process_kallsyms) < 0) 1969 return -1; 1970 1971 return 0; 1972 } 1973 1974 static int kcore_copy__process_modules(void *arg, 1975 const char *name __maybe_unused, 1976 u64 start, u64 size __maybe_unused) 1977 { 1978 struct kcore_copy_info *kci = arg; 1979 1980 if (!kci->first_module || start < kci->first_module) 1981 kci->first_module = start; 1982 1983 return 0; 1984 } 1985 1986 static int kcore_copy__parse_modules(struct kcore_copy_info *kci, 1987 const char *dir) 1988 { 1989 char modules_filename[PATH_MAX]; 1990 1991 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); 1992 1993 if (symbol__restricted_filename(modules_filename, "/proc/modules")) 1994 return -1; 1995 1996 if (modules__parse(modules_filename, kci, 1997 kcore_copy__process_modules) < 0) 1998 return -1; 1999 2000 return 0; 2001 } 2002 2003 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end, 2004 u64 pgoff, u64 s, u64 e) 2005 { 2006 u64 len, offset; 2007 2008 if (s < start || s >= end) 2009 return 0; 2010 2011 offset = (s - start) + pgoff; 2012 len = e < end ? e - s : end - s; 2013 2014 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1; 2015 } 2016 2017 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) 2018 { 2019 struct kcore_copy_info *kci = data; 2020 u64 end = start + len; 2021 struct sym_data *sdat; 2022 2023 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext)) 2024 return -1; 2025 2026 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module, 2027 kci->last_module_symbol)) 2028 return -1; 2029 2030 list_for_each_entry(sdat, &kci->syms, node) { 2031 u64 s = round_down(sdat->addr, page_size); 2032 2033 if (kcore_copy__map(kci, start, end, pgoff, s, s + len)) 2034 return -1; 2035 } 2036 2037 return 0; 2038 } 2039 2040 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) 2041 { 2042 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) 2043 return -1; 2044 2045 return 0; 2046 } 2047 2048 static void kcore_copy__find_remaps(struct kcore_copy_info *kci) 2049 { 2050 struct phdr_data *p, *k = NULL; 2051 u64 kend; 2052 2053 if (!kci->stext) 2054 return; 2055 2056 /* Find phdr that corresponds to the kernel map (contains stext) */ 2057 kcore_copy__for_each_phdr(kci, p) { 2058 u64 pend = p->addr + p->len - 1; 2059 2060 if (p->addr <= kci->stext && pend >= kci->stext) { 2061 k = p; 2062 break; 2063 } 2064 } 2065 2066 if (!k) 2067 return; 2068 2069 kend = k->offset + k->len; 2070 2071 /* Find phdrs that remap the kernel */ 2072 kcore_copy__for_each_phdr(kci, p) { 2073 u64 pend = p->offset + p->len; 2074 2075 if (p == k) 2076 continue; 2077 2078 if (p->offset >= k->offset && pend <= kend) 2079 p->remaps = k; 2080 } 2081 } 2082 2083 static void kcore_copy__layout(struct kcore_copy_info *kci) 2084 { 2085 struct phdr_data *p; 2086 off_t rel = 0; 2087 2088 kcore_copy__find_remaps(kci); 2089 2090 kcore_copy__for_each_phdr(kci, p) { 2091 if (!p->remaps) { 2092 p->rel = rel; 2093 rel += p->len; 2094 } 2095 kci->phnum += 1; 2096 } 2097 2098 kcore_copy__for_each_phdr(kci, p) { 2099 struct phdr_data *k = p->remaps; 2100 2101 if (k) 2102 p->rel = p->offset - k->offset + k->rel; 2103 } 2104 } 2105 2106 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, 2107 Elf *elf) 2108 { 2109 if (kcore_copy__parse_kallsyms(kci, dir)) 2110 return -1; 2111 2112 if (kcore_copy__parse_modules(kci, dir)) 2113 return -1; 2114 2115 if (kci->stext) 2116 kci->stext = round_down(kci->stext, page_size); 2117 else 2118 kci->stext = round_down(kci->first_symbol, page_size); 2119 2120 if (kci->etext) { 2121 kci->etext = round_up(kci->etext, page_size); 2122 } else if (kci->last_symbol) { 2123 kci->etext = round_up(kci->last_symbol, page_size); 2124 kci->etext += page_size; 2125 } 2126 2127 if (kci->first_module_symbol && 2128 (!kci->first_module || kci->first_module_symbol < kci->first_module)) 2129 kci->first_module = kci->first_module_symbol; 2130 2131 kci->first_module = round_down(kci->first_module, page_size); 2132 2133 if (kci->last_module_symbol) { 2134 kci->last_module_symbol = round_up(kci->last_module_symbol, 2135 page_size); 2136 kci->last_module_symbol += page_size; 2137 } 2138 2139 if (!kci->stext || !kci->etext) 2140 return -1; 2141 2142 if (kci->first_module && !kci->last_module_symbol) 2143 return -1; 2144 2145 if (kcore_copy__read_maps(kci, elf)) 2146 return -1; 2147 2148 kcore_copy__layout(kci); 2149 2150 return 0; 2151 } 2152 2153 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, 2154 const char *name) 2155 { 2156 char from_filename[PATH_MAX]; 2157 char to_filename[PATH_MAX]; 2158 2159 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 2160 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 2161 2162 return copyfile_mode(from_filename, to_filename, 0400); 2163 } 2164 2165 static int kcore_copy__unlink(const char *dir, const char *name) 2166 { 2167 char filename[PATH_MAX]; 2168 2169 scnprintf(filename, PATH_MAX, "%s/%s", dir, name); 2170 2171 return unlink(filename); 2172 } 2173 2174 static int kcore_copy__compare_fds(int from, int to) 2175 { 2176 char *buf_from; 2177 char *buf_to; 2178 ssize_t ret; 2179 size_t len; 2180 int err = -1; 2181 2182 buf_from = malloc(page_size); 2183 buf_to = malloc(page_size); 2184 if (!buf_from || !buf_to) 2185 goto out; 2186 2187 while (1) { 2188 /* Use read because mmap won't work on proc files */ 2189 ret = read(from, buf_from, page_size); 2190 if (ret < 0) 2191 goto out; 2192 2193 if (!ret) 2194 break; 2195 2196 len = ret; 2197 2198 if (readn(to, buf_to, len) != (int)len) 2199 goto out; 2200 2201 if (memcmp(buf_from, buf_to, len)) 2202 goto out; 2203 } 2204 2205 err = 0; 2206 out: 2207 free(buf_to); 2208 free(buf_from); 2209 return err; 2210 } 2211 2212 static int kcore_copy__compare_files(const char *from_filename, 2213 const char *to_filename) 2214 { 2215 int from, to, err = -1; 2216 2217 from = open(from_filename, O_RDONLY); 2218 if (from < 0) 2219 return -1; 2220 2221 to = open(to_filename, O_RDONLY); 2222 if (to < 0) 2223 goto out_close_from; 2224 2225 err = kcore_copy__compare_fds(from, to); 2226 2227 close(to); 2228 out_close_from: 2229 close(from); 2230 return err; 2231 } 2232 2233 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, 2234 const char *name) 2235 { 2236 char from_filename[PATH_MAX]; 2237 char to_filename[PATH_MAX]; 2238 2239 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); 2240 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); 2241 2242 return kcore_copy__compare_files(from_filename, to_filename); 2243 } 2244 2245 /** 2246 * kcore_copy - copy kallsyms, modules and kcore from one directory to another. 2247 * @from_dir: from directory 2248 * @to_dir: to directory 2249 * 2250 * This function copies kallsyms, modules and kcore files from one directory to 2251 * another. kallsyms and modules are copied entirely. Only code segments are 2252 * copied from kcore. It is assumed that two segments suffice: one for the 2253 * kernel proper and one for all the modules. The code segments are determined 2254 * from kallsyms and modules files. The kernel map starts at _stext or the 2255 * lowest function symbol, and ends at _etext or the highest function symbol. 2256 * The module map starts at the lowest module address and ends at the highest 2257 * module symbol. Start addresses are rounded down to the nearest page. End 2258 * addresses are rounded up to the nearest page. An extra page is added to the 2259 * highest kernel symbol and highest module symbol to, hopefully, encompass that 2260 * symbol too. Because it contains only code sections, the resulting kcore is 2261 * unusual. One significant peculiarity is that the mapping (start -> pgoff) 2262 * is not the same for the kernel map and the modules map. That happens because 2263 * the data is copied adjacently whereas the original kcore has gaps. Finally, 2264 * kallsyms file is compared with its copy to check that modules have not been 2265 * loaded or unloaded while the copies were taking place. 2266 * 2267 * Return: %0 on success, %-1 on failure. 2268 */ 2269 int kcore_copy(const char *from_dir, const char *to_dir) 2270 { 2271 struct kcore kcore; 2272 struct kcore extract; 2273 int idx = 0, err = -1; 2274 off_t offset, sz; 2275 struct kcore_copy_info kci = { .stext = 0, }; 2276 char kcore_filename[PATH_MAX]; 2277 char extract_filename[PATH_MAX]; 2278 struct phdr_data *p; 2279 2280 INIT_LIST_HEAD(&kci.phdrs); 2281 INIT_LIST_HEAD(&kci.syms); 2282 2283 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) 2284 return -1; 2285 2286 if (kcore_copy__copy_file(from_dir, to_dir, "modules")) 2287 goto out_unlink_kallsyms; 2288 2289 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); 2290 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); 2291 2292 if (kcore__open(&kcore, kcore_filename)) 2293 goto out_unlink_modules; 2294 2295 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) 2296 goto out_kcore_close; 2297 2298 if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) 2299 goto out_kcore_close; 2300 2301 if (kcore__copy_hdr(&kcore, &extract, kci.phnum)) 2302 goto out_extract_close; 2303 2304 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) + 2305 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT); 2306 offset = round_up(offset, page_size); 2307 2308 kcore_copy__for_each_phdr(&kci, p) { 2309 off_t offs = p->rel + offset; 2310 2311 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len)) 2312 goto out_extract_close; 2313 } 2314 2315 sz = kcore__write(&extract); 2316 if (sz < 0 || sz > offset) 2317 goto out_extract_close; 2318 2319 kcore_copy__for_each_phdr(&kci, p) { 2320 off_t offs = p->rel + offset; 2321 2322 if (p->remaps) 2323 continue; 2324 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len)) 2325 goto out_extract_close; 2326 } 2327 2328 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) 2329 goto out_extract_close; 2330 2331 err = 0; 2332 2333 out_extract_close: 2334 kcore__close(&extract); 2335 if (err) 2336 unlink(extract_filename); 2337 out_kcore_close: 2338 kcore__close(&kcore); 2339 out_unlink_modules: 2340 if (err) 2341 kcore_copy__unlink(to_dir, "modules"); 2342 out_unlink_kallsyms: 2343 if (err) 2344 kcore_copy__unlink(to_dir, "kallsyms"); 2345 2346 kcore_copy__free_phdrs(&kci); 2347 kcore_copy__free_syms(&kci); 2348 2349 return err; 2350 } 2351 2352 int kcore_extract__create(struct kcore_extract *kce) 2353 { 2354 struct kcore kcore; 2355 struct kcore extract; 2356 size_t count = 1; 2357 int idx = 0, err = -1; 2358 off_t offset = page_size, sz; 2359 2360 if (kcore__open(&kcore, kce->kcore_filename)) 2361 return -1; 2362 2363 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); 2364 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) 2365 goto out_kcore_close; 2366 2367 if (kcore__copy_hdr(&kcore, &extract, count)) 2368 goto out_extract_close; 2369 2370 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) 2371 goto out_extract_close; 2372 2373 sz = kcore__write(&extract); 2374 if (sz < 0 || sz > offset) 2375 goto out_extract_close; 2376 2377 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) 2378 goto out_extract_close; 2379 2380 err = 0; 2381 2382 out_extract_close: 2383 kcore__close(&extract); 2384 if (err) 2385 unlink(kce->extract_filename); 2386 out_kcore_close: 2387 kcore__close(&kcore); 2388 2389 return err; 2390 } 2391 2392 void kcore_extract__delete(struct kcore_extract *kce) 2393 { 2394 unlink(kce->extract_filename); 2395 } 2396 2397 #ifdef HAVE_GELF_GETNOTE_SUPPORT 2398 2399 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off) 2400 { 2401 if (!base_off) 2402 return; 2403 2404 if (tmp->bit32) 2405 tmp->addr.a32[SDT_NOTE_IDX_LOC] = 2406 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off - 2407 tmp->addr.a32[SDT_NOTE_IDX_BASE]; 2408 else 2409 tmp->addr.a64[SDT_NOTE_IDX_LOC] = 2410 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off - 2411 tmp->addr.a64[SDT_NOTE_IDX_BASE]; 2412 } 2413 2414 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr, 2415 GElf_Addr base_off) 2416 { 2417 if (!base_off) 2418 return; 2419 2420 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR]) 2421 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2422 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR]) 2423 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); 2424 } 2425 2426 /** 2427 * populate_sdt_note : Parse raw data and identify SDT note 2428 * @elf: elf of the opened file 2429 * @data: raw data of a section with description offset applied 2430 * @len: note description size 2431 * @type: type of the note 2432 * @sdt_notes: List to add the SDT note 2433 * 2434 * Responsible for parsing the @data in section .note.stapsdt in @elf and 2435 * if its an SDT note, it appends to @sdt_notes list. 2436 */ 2437 static int populate_sdt_note(Elf **elf, const char *data, size_t len, 2438 struct list_head *sdt_notes) 2439 { 2440 const char *provider, *name, *args; 2441 struct sdt_note *tmp = NULL; 2442 GElf_Ehdr ehdr; 2443 GElf_Shdr shdr; 2444 int ret = -EINVAL; 2445 2446 union { 2447 Elf64_Addr a64[NR_ADDR]; 2448 Elf32_Addr a32[NR_ADDR]; 2449 } buf; 2450 2451 Elf_Data dst = { 2452 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, 2453 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), 2454 .d_off = 0, .d_align = 0 2455 }; 2456 Elf_Data src = { 2457 .d_buf = (void *) data, .d_type = ELF_T_ADDR, 2458 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, 2459 .d_align = 0 2460 }; 2461 2462 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); 2463 if (!tmp) { 2464 ret = -ENOMEM; 2465 goto out_err; 2466 } 2467 2468 INIT_LIST_HEAD(&tmp->note_list); 2469 2470 if (len < dst.d_size + 3) 2471 goto out_free_note; 2472 2473 /* Translation from file representation to memory representation */ 2474 if (gelf_xlatetom(*elf, &dst, &src, 2475 elf_getident(*elf, NULL)[EI_DATA]) == NULL) { 2476 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); 2477 goto out_free_note; 2478 } 2479 2480 /* Populate the fields of sdt_note */ 2481 provider = data + dst.d_size; 2482 2483 name = (const char *)memchr(provider, '\0', data + len - provider); 2484 if (name++ == NULL) 2485 goto out_free_note; 2486 2487 tmp->provider = strdup(provider); 2488 if (!tmp->provider) { 2489 ret = -ENOMEM; 2490 goto out_free_note; 2491 } 2492 tmp->name = strdup(name); 2493 if (!tmp->name) { 2494 ret = -ENOMEM; 2495 goto out_free_prov; 2496 } 2497 2498 args = memchr(name, '\0', data + len - name); 2499 2500 /* 2501 * There is no argument if: 2502 * - We reached the end of the note; 2503 * - There is not enough room to hold a potential string; 2504 * - The argument string is empty or just contains ':'. 2505 */ 2506 if (args == NULL || data + len - args < 2 || 2507 args[1] == ':' || args[1] == '\0') 2508 tmp->args = NULL; 2509 else { 2510 tmp->args = strdup(++args); 2511 if (!tmp->args) { 2512 ret = -ENOMEM; 2513 goto out_free_name; 2514 } 2515 } 2516 2517 if (gelf_getclass(*elf) == ELFCLASS32) { 2518 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); 2519 tmp->bit32 = true; 2520 } else { 2521 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); 2522 tmp->bit32 = false; 2523 } 2524 2525 if (!gelf_getehdr(*elf, &ehdr)) { 2526 pr_debug("%s : cannot get elf header.\n", __func__); 2527 ret = -EBADF; 2528 goto out_free_args; 2529 } 2530 2531 /* Adjust the prelink effect : 2532 * Find out the .stapsdt.base section. 2533 * This scn will help us to handle prelinking (if present). 2534 * Compare the retrieved file offset of the base section with the 2535 * base address in the description of the SDT note. If its different, 2536 * then accordingly, adjust the note location. 2537 */ 2538 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) 2539 sdt_adjust_loc(tmp, shdr.sh_offset); 2540 2541 /* Adjust reference counter offset */ 2542 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) 2543 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset); 2544 2545 list_add_tail(&tmp->note_list, sdt_notes); 2546 return 0; 2547 2548 out_free_args: 2549 zfree(&tmp->args); 2550 out_free_name: 2551 zfree(&tmp->name); 2552 out_free_prov: 2553 zfree(&tmp->provider); 2554 out_free_note: 2555 free(tmp); 2556 out_err: 2557 return ret; 2558 } 2559 2560 /** 2561 * construct_sdt_notes_list : constructs a list of SDT notes 2562 * @elf : elf to look into 2563 * @sdt_notes : empty list_head 2564 * 2565 * Scans the sections in 'elf' for the section 2566 * .note.stapsdt. It, then calls populate_sdt_note to find 2567 * out the SDT events and populates the 'sdt_notes'. 2568 */ 2569 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) 2570 { 2571 GElf_Ehdr ehdr; 2572 Elf_Scn *scn = NULL; 2573 Elf_Data *data; 2574 GElf_Shdr shdr; 2575 size_t shstrndx, next; 2576 GElf_Nhdr nhdr; 2577 size_t name_off, desc_off, offset; 2578 int ret = 0; 2579 2580 if (gelf_getehdr(elf, &ehdr) == NULL) { 2581 ret = -EBADF; 2582 goto out_ret; 2583 } 2584 if (elf_getshdrstrndx(elf, &shstrndx) != 0) { 2585 ret = -EBADF; 2586 goto out_ret; 2587 } 2588 2589 /* Look for the required section */ 2590 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); 2591 if (!scn) { 2592 ret = -ENOENT; 2593 goto out_ret; 2594 } 2595 2596 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { 2597 ret = -ENOENT; 2598 goto out_ret; 2599 } 2600 2601 data = elf_getdata(scn, NULL); 2602 2603 /* Get the SDT notes */ 2604 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, 2605 &desc_off)) > 0; offset = next) { 2606 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && 2607 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, 2608 sizeof(SDT_NOTE_NAME))) { 2609 /* Check the type of the note */ 2610 if (nhdr.n_type != SDT_NOTE_TYPE) 2611 goto out_ret; 2612 2613 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), 2614 nhdr.n_descsz, sdt_notes); 2615 if (ret < 0) 2616 goto out_ret; 2617 } 2618 } 2619 if (list_empty(sdt_notes)) 2620 ret = -ENOENT; 2621 2622 out_ret: 2623 return ret; 2624 } 2625 2626 /** 2627 * get_sdt_note_list : Wrapper to construct a list of sdt notes 2628 * @head : empty list_head 2629 * @target : file to find SDT notes from 2630 * 2631 * This opens the file, initializes 2632 * the ELF and then calls construct_sdt_notes_list. 2633 */ 2634 int get_sdt_note_list(struct list_head *head, const char *target) 2635 { 2636 Elf *elf; 2637 int fd, ret; 2638 2639 fd = open(target, O_RDONLY); 2640 if (fd < 0) 2641 return -EBADF; 2642 2643 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); 2644 if (!elf) { 2645 ret = -EBADF; 2646 goto out_close; 2647 } 2648 ret = construct_sdt_notes_list(elf, head); 2649 elf_end(elf); 2650 out_close: 2651 close(fd); 2652 return ret; 2653 } 2654 2655 /** 2656 * cleanup_sdt_note_list : free the sdt notes' list 2657 * @sdt_notes: sdt notes' list 2658 * 2659 * Free up the SDT notes in @sdt_notes. 2660 * Returns the number of SDT notes free'd. 2661 */ 2662 int cleanup_sdt_note_list(struct list_head *sdt_notes) 2663 { 2664 struct sdt_note *tmp, *pos; 2665 int nr_free = 0; 2666 2667 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { 2668 list_del_init(&pos->note_list); 2669 zfree(&pos->args); 2670 zfree(&pos->name); 2671 zfree(&pos->provider); 2672 free(pos); 2673 nr_free++; 2674 } 2675 return nr_free; 2676 } 2677 2678 /** 2679 * sdt_notes__get_count: Counts the number of sdt events 2680 * @start: list_head to sdt_notes list 2681 * 2682 * Returns the number of SDT notes in a list 2683 */ 2684 int sdt_notes__get_count(struct list_head *start) 2685 { 2686 struct sdt_note *sdt_ptr; 2687 int count = 0; 2688 2689 list_for_each_entry(sdt_ptr, start, note_list) 2690 count++; 2691 return count; 2692 } 2693 #endif 2694 2695 void symbol__elf_init(void) 2696 { 2697 elf_version(EV_CURRENT); 2698 } 2699