tools/perf/util/symbol-elf.c

   1 #include <fcntl.h>
   2 #include <stdio.h>
   3 #include <errno.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <inttypes.h>
   7
   8 #include "symbol.h"
   9 #include <symbol/kallsyms.h>
  10 #include "debug.h"
  11
  12 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  13 static int elf_getphdrnum(Elf *elf, size_t *dst)
  14 {
  15         GElf_Ehdr gehdr;
  16         GElf_Ehdr *ehdr;
  17
  18         ehdr = gelf_getehdr(elf, &gehdr);
  19         if (!ehdr)
  20                 return -1;
  21
  22         *dst = ehdr->e_phnum;
  23
  24         return 0;
  25 }
  26 #endif
  27
  28 #ifndef NT_GNU_BUILD_ID
  29 #define NT_GNU_BUILD_ID 3
  30 #endif
  31
  32 /**
  33  * elf_symtab__for_each_symbol - iterate thru all the symbols
  34  *
  35  * @syms: struct elf_symtab instance to iterate
  36  * @idx: uint32_t idx
  37  * @sym: GElf_Sym iterator
  38  */
  39 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  40         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  41              idx < nr_syms; \
  42              idx++, gelf_getsym(syms, idx, &sym))
  43
  44 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  45 {
  46         return GELF_ST_TYPE(sym->st_info);
  47 }
  48
  49 static inline int elf_sym__is_function(const GElf_Sym *sym)
  50 {
  51         return elf_sym__type(sym) == STT_FUNC &&
  52                sym->st_name != 0 &&
  53                sym->st_shndx != SHN_UNDEF;
  54 }
  55
  56 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  57 {
  58         return elf_sym__type(sym) == STT_OBJECT &&
  59                 sym->st_name != 0 &&
  60                 sym->st_shndx != SHN_UNDEF;
  61 }
  62
  63 static inline int elf_sym__is_label(const GElf_Sym *sym)
  64 {
  65         return elf_sym__type(sym) == STT_NOTYPE &&
  66                 sym->st_name != 0 &&
  67                 sym->st_shndx != SHN_UNDEF &&
  68                 sym->st_shndx != SHN_ABS;
  69 }
  70
  71 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
  72 {
  73         switch (type) {
  74         case MAP__FUNCTION:
  75                 return elf_sym__is_function(sym);
  76         case MAP__VARIABLE:
  77                 return elf_sym__is_object(sym);
  78         default:
  79                 return false;
  80         }
  81 }
  82
  83 static inline const char *elf_sym__name(const GElf_Sym *sym,
  84                                         const Elf_Data *symstrs)
  85 {
  86         return symstrs->d_buf + sym->st_name;
  87 }
  88
  89 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  90                                         const Elf_Data *secstrs)
  91 {
  92         return secstrs->d_buf + shdr->sh_name;
  93 }
  94
  95 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  96                                         const Elf_Data *secstrs)
  97 {
  98         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
  99 }
 100
 101 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 102                                     const Elf_Data *secstrs)
 103 {
 104         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 105 }
 106
 107 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 108                           enum map_type type)
 109 {
 110         switch (type) {
 111         case MAP__FUNCTION:
 112                 return elf_sec__is_text(shdr, secstrs);
 113         case MAP__VARIABLE:
 114                 return elf_sec__is_data(shdr, secstrs);
 115         default:
 116                 return false;
 117         }
 118 }
 119
 120 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 121 {
 122         Elf_Scn *sec = NULL;
 123         GElf_Shdr shdr;
 124         size_t cnt = 1;
 125
 126         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 127                 gelf_getshdr(sec, &shdr);
 128
 129                 if ((addr >= shdr.sh_addr) &&
 130                     (addr < (shdr.sh_addr + shdr.sh_size)))
 131                         return cnt;
 132
 133                 ++cnt;
 134         }
 135
 136         return -1;
 137 }
 138
 139 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 140                              GElf_Shdr *shp, const char *name, size_t *idx)
 141 {
 142         Elf_Scn *sec = NULL;
 143         size_t cnt = 1;
 144
 145         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 146         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 147                 return NULL;
 148
 149         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 150                 char *str;
 151
 152                 gelf_getshdr(sec, shp);
 153                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 154                 if (!strcmp(name, str)) {
 155                         if (idx)
 156                                 *idx = cnt;
 157                         break;
 158                 }
 159                 ++cnt;
 160         }
 161
 162         return sec;
 163 }
 164
 165 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 166         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 167              idx < nr_entries; \
 168              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 169
 170 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 171         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 172              idx < nr_entries; \
 173              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 174
 175 /*
 176  * We need to check if we have a .dynsym, so that we can handle the
 177  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 178  * .dynsym or .symtab).
 179  * And always look at the original dso, not at debuginfo packages, that
 180  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 181  */
 182 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 183                                 symbol_filter_t filter)
 184 {
 185         uint32_t nr_rel_entries, idx;
 186         GElf_Sym sym;
 187         u64 plt_offset;
 188         GElf_Shdr shdr_plt;
 189         struct symbol *f;
 190         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 191         Elf_Data *reldata, *syms, *symstrs;
 192         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 193         size_t dynsym_idx;
 194         GElf_Ehdr ehdr;
 195         char sympltname[1024];
 196         Elf *elf;
 197         int nr = 0, symidx, err = 0;
 198
 199         if (!ss->dynsym)
 200                 return 0;
 201
 202         elf = ss->elf;
 203         ehdr = ss->ehdr;
 204
 205         scn_dynsym = ss->dynsym;
 206         shdr_dynsym = ss->dynshdr;
 207         dynsym_idx = ss->dynsym_idx;
 208
 209         if (scn_dynsym == NULL)
 210                 goto out_elf_end;
 211
 212         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 213                                           ".rela.plt", NULL);
 214         if (scn_plt_rel == NULL) {
 215                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 216                                                   ".rel.plt", NULL);
 217                 if (scn_plt_rel == NULL)
 218                         goto out_elf_end;
 219         }
 220
 221         err = -1;
 222
 223         if (shdr_rel_plt.sh_link != dynsym_idx)
 224                 goto out_elf_end;
 225
 226         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 227                 goto out_elf_end;
 228
 229         /*
 230          * Fetch the relocation section to find the idxes to the GOT
 231          * and the symbols in the .dynsym they refer to.
 232          */
 233         reldata = elf_getdata(scn_plt_rel, NULL);
 234         if (reldata == NULL)
 235                 goto out_elf_end;
 236
 237         syms = elf_getdata(scn_dynsym, NULL);
 238         if (syms == NULL)
 239                 goto out_elf_end;
 240
 241         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 242         if (scn_symstrs == NULL)
 243                 goto out_elf_end;
 244
 245         symstrs = elf_getdata(scn_symstrs, NULL);
 246         if (symstrs == NULL)
 247                 goto out_elf_end;
 248
 249         if (symstrs->d_size == 0)
 250                 goto out_elf_end;
 251
 252         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 253         plt_offset = shdr_plt.sh_offset;
 254
 255         if (shdr_rel_plt.sh_type == SHT_RELA) {
 256                 GElf_Rela pos_mem, *pos;
 257
 258                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 259                                            nr_rel_entries) {
 260                         symidx = GELF_R_SYM(pos->r_info);
 261                         plt_offset += shdr_plt.sh_entsize;
 262                         gelf_getsym(syms, symidx, &sym);
 263                         snprintf(sympltname, sizeof(sympltname),
 264                                  "%s@plt", elf_sym__name(&sym, symstrs));
 265
 266                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 267                                         STB_GLOBAL, sympltname);
 268                         if (!f)
 269                                 goto out_elf_end;
 270
 271                         if (filter && filter(map, f))
 272                                 symbol__delete(f);
 273                         else {
 274                                 symbols__insert(&dso->symbols[map->type], f);
 275                                 ++nr;
 276                         }
 277                 }
 278         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 279                 GElf_Rel pos_mem, *pos;
 280                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 281                                           nr_rel_entries) {
 282                         symidx = GELF_R_SYM(pos->r_info);
 283                         plt_offset += shdr_plt.sh_entsize;
 284                         gelf_getsym(syms, symidx, &sym);
 285                         snprintf(sympltname, sizeof(sympltname),
 286                                  "%s@plt", elf_sym__name(&sym, symstrs));
 287
 288                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 289                                         STB_GLOBAL, sympltname);
 290                         if (!f)
 291                                 goto out_elf_end;
 292
 293                         if (filter && filter(map, f))
 294                                 symbol__delete(f);
 295                         else {
 296                                 symbols__insert(&dso->symbols[map->type], f);
 297                                 ++nr;
 298                         }
 299                 }
 300         }
 301
 302         err = 0;
 303 out_elf_end:
 304         if (err == 0)
 305                 return nr;
 306         pr_debug("%s: problems reading %s PLT info.\n",
 307                  __func__, dso->long_name);
 308         return 0;
 309 }
 310
 311 /*
 312  * Align offset to 4 bytes as needed for note name and descriptor data.
 313  */
 314 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 315
 316 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 317 {
 318         int err = -1;
 319         GElf_Ehdr ehdr;
 320         GElf_Shdr shdr;
 321         Elf_Data *data;
 322         Elf_Scn *sec;
 323         Elf_Kind ek;
 324         void *ptr;
 325
 326         if (size < BUILD_ID_SIZE)
 327                 goto out;
 328
 329         ek = elf_kind(elf);
 330         if (ek != ELF_K_ELF)
 331                 goto out;
 332
 333         if (gelf_getehdr(elf, &ehdr) == NULL) {
 334                 pr_err("%s: cannot get elf header.\n", __func__);
 335                 goto out;
 336         }
 337
 338         /*
 339          * Check following sections for notes:
 340          *   '.note.gnu.build-id'
 341          *   '.notes'
 342          *   '.note' (VDSO specific)
 343          */
 344         do {
 345                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 346                                           ".note.gnu.build-id", NULL);
 347                 if (sec)
 348                         break;
 349
 350                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 351                                           ".notes", NULL);
 352                 if (sec)
 353                         break;
 354
 355                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 356                                           ".note", NULL);
 357                 if (sec)
 358                         break;
 359
 360                 return err;
 361
 362         } while (0);
 363
 364         data = elf_getdata(sec, NULL);
 365         if (data == NULL)
 366                 goto out;
 367
 368         ptr = data->d_buf;
 369         while (ptr < (data->d_buf + data->d_size)) {
 370                 GElf_Nhdr *nhdr = ptr;
 371                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 372                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 373                 const char *name;
 374
 375                 ptr += sizeof(*nhdr);
 376                 name = ptr;
 377                 ptr += namesz;
 378                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 379                     nhdr->n_namesz == sizeof("GNU")) {
 380                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 381                                 size_t sz = min(size, descsz);
 382                                 memcpy(bf, ptr, sz);
 383                                 memset(bf + sz, 0, size - sz);
 384                                 err = descsz;
 385                                 break;
 386                         }
 387                 }
 388                 ptr += descsz;
 389         }
 390
 391 out:
 392         return err;
 393 }
 394
 395 int filename__read_build_id(const char *filename, void *bf, size_t size)
 396 {
 397         int fd, err = -1;
 398         Elf *elf;
 399
 400         if (size < BUILD_ID_SIZE)
 401                 goto out;
 402
 403         fd = open(filename, O_RDONLY);
 404         if (fd < 0)
 405                 goto out;
 406
 407         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 408         if (elf == NULL) {
 409                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 410                 goto out_close;
 411         }
 412
 413         err = elf_read_build_id(elf, bf, size);
 414
 415         elf_end(elf);
 416 out_close:
 417         close(fd);
 418 out:
 419         return err;
 420 }
 421
 422 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 423 {
 424         int fd, err = -1;
 425
 426         if (size < BUILD_ID_SIZE)
 427                 goto out;
 428
 429         fd = open(filename, O_RDONLY);
 430         if (fd < 0)
 431                 goto out;
 432
 433         while (1) {
 434                 char bf[BUFSIZ];
 435                 GElf_Nhdr nhdr;
 436                 size_t namesz, descsz;
 437
 438                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 439                         break;
 440
 441                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 442                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 443                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 444                     nhdr.n_namesz == sizeof("GNU")) {
 445                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 446                                 break;
 447                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 448                                 size_t sz = min(descsz, size);
 449                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 450                                         memset(build_id + sz, 0, size - sz);
 451                                         err = 0;
 452                                         break;
 453                                 }
 454                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 455                                 break;
 456                 } else {
 457                         int n = namesz + descsz;
 458                         if (read(fd, bf, n) != n)
 459                                 break;
 460                 }
 461         }
 462         close(fd);
 463 out:
 464         return err;
 465 }
 466
 467 int filename__read_debuglink(const char *filename, char *debuglink,
 468                              size_t size)
 469 {
 470         int fd, err = -1;
 471         Elf *elf;
 472         GElf_Ehdr ehdr;
 473         GElf_Shdr shdr;
 474         Elf_Data *data;
 475         Elf_Scn *sec;
 476         Elf_Kind ek;
 477
 478         fd = open(filename, O_RDONLY);
 479         if (fd < 0)
 480                 goto out;
 481
 482         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 483         if (elf == NULL) {
 484                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 485                 goto out_close;
 486         }
 487
 488         ek = elf_kind(elf);
 489         if (ek != ELF_K_ELF)
 490                 goto out_elf_end;
 491
 492         if (gelf_getehdr(elf, &ehdr) == NULL) {
 493                 pr_err("%s: cannot get elf header.\n", __func__);
 494                 goto out_elf_end;
 495         }
 496
 497         sec = elf_section_by_name(elf, &ehdr, &shdr,
 498                                   ".gnu_debuglink", NULL);
 499         if (sec == NULL)
 500                 goto out_elf_end;
 501
 502         data = elf_getdata(sec, NULL);
 503         if (data == NULL)
 504                 goto out_elf_end;
 505
 506         /* the start of this section is a zero-terminated string */
 507         strncpy(debuglink, data->d_buf, size);
 508
 509 out_elf_end:
 510         elf_end(elf);
 511 out_close:
 512         close(fd);
 513 out:
 514         return err;
 515 }
 516
 517 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 518 {
 519         static unsigned int const endian = 1;
 520
 521         dso->needs_swap = DSO_SWAP__NO;
 522
 523         switch (eidata) {
 524         case ELFDATA2LSB:
 525                 /* We are big endian, DSO is little endian. */
 526                 if (*(unsigned char const *)&endian != 1)
 527                         dso->needs_swap = DSO_SWAP__YES;
 528                 break;
 529
 530         case ELFDATA2MSB:
 531                 /* We are little endian, DSO is big endian. */
 532                 if (*(unsigned char const *)&endian != 0)
 533                         dso->needs_swap = DSO_SWAP__YES;
 534                 break;
 535
 536         default:
 537                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 538                 return -EINVAL;
 539         }
 540
 541         return 0;
 542 }
 543
 544 bool symsrc__possibly_runtime(struct symsrc *ss)
 545 {
 546         return ss->dynsym || ss->opdsec;
 547 }
 548
 549 bool symsrc__has_symtab(struct symsrc *ss)
 550 {
 551         return ss->symtab != NULL;
 552 }
 553
 554 void symsrc__destroy(struct symsrc *ss)
 555 {
 556         zfree(&ss->name);
 557         elf_end(ss->elf);
 558         close(ss->fd);
 559 }
 560
 561 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 562                  enum dso_binary_type type)
 563 {
 564         int err = -1;
 565         GElf_Ehdr ehdr;
 566         Elf *elf;
 567         int fd;
 568
 569         fd = open(name, O_RDONLY);
 570         if (fd < 0)
 571                 return -1;
 572
 573         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 574         if (elf == NULL) {
 575                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 576                 goto out_close;
 577         }
 578
 579         if (gelf_getehdr(elf, &ehdr) == NULL) {
 580                 pr_debug("%s: cannot get elf header.\n", __func__);
 581                 goto out_elf_end;
 582         }
 583
 584         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 585                 goto out_elf_end;
 586
 587         /* Always reject images with a mismatched build-id: */
 588         if (dso->has_build_id) {
 589                 u8 build_id[BUILD_ID_SIZE];
 590
 591                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 592                         goto out_elf_end;
 593
 594                 if (!dso__build_id_equal(dso, build_id))
 595                         goto out_elf_end;
 596         }
 597
 598         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 599                         NULL);
 600         if (ss->symshdr.sh_type != SHT_SYMTAB)
 601                 ss->symtab = NULL;
 602
 603         ss->dynsym_idx = 0;
 604         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 605                         &ss->dynsym_idx);
 606         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 607                 ss->dynsym = NULL;
 608
 609         ss->opdidx = 0;
 610         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 611                         &ss->opdidx);
 612         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 613                 ss->opdsec = NULL;
 614
 615         if (dso->kernel == DSO_TYPE_USER) {
 616                 GElf_Shdr shdr;
 617                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 618                                 ehdr.e_type == ET_REL ||
 619                                 elf_section_by_name(elf, &ehdr, &shdr,
 620                                                      ".gnu.prelink_undo",
 621                                                      NULL) != NULL);
 622         } else {
 623                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 624                                      ehdr.e_type == ET_REL;
 625         }
 626
 627         ss->name   = strdup(name);
 628         if (!ss->name)
 629                 goto out_elf_end;
 630
 631         ss->elf    = elf;
 632         ss->fd     = fd;
 633         ss->ehdr   = ehdr;
 634         ss->type   = type;
 635
 636         return 0;
 637
 638 out_elf_end:
 639         elf_end(elf);
 640 out_close:
 641         close(fd);
 642         return err;
 643 }
 644
 645 /**
 646  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 647  * @kmap: kernel maps and relocation reference symbol
 648  *
 649  * This function returns %true if we are dealing with the kernel maps and the
 650  * relocation reference symbol has not yet been found.  Otherwise %false is
 651  * returned.
 652  */
 653 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 654 {
 655         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 656                !kmap->ref_reloc_sym->unrelocated_addr;
 657 }
 658
 659 /**
 660  * ref_reloc - kernel relocation offset.
 661  * @kmap: kernel maps and relocation reference symbol
 662  *
 663  * This function returns the offset of kernel addresses as determined by using
 664  * the relocation reference symbol i.e. if the kernel has not been relocated
 665  * then the return value is zero.
 666  */
 667 static u64 ref_reloc(struct kmap *kmap)
 668 {
 669         if (kmap && kmap->ref_reloc_sym &&
 670             kmap->ref_reloc_sym->unrelocated_addr)
 671                 return kmap->ref_reloc_sym->addr -
 672                        kmap->ref_reloc_sym->unrelocated_addr;
 673         return 0;
 674 }
 675
 676 int dso__load_sym(struct dso *dso, struct map *map,
 677                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 678                   symbol_filter_t filter, int kmodule)
 679 {
 680         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 681         struct map *curr_map = map;
 682         struct dso *curr_dso = dso;
 683         Elf_Data *symstrs, *secstrs;
 684         uint32_t nr_syms;
 685         int err = -1;
 686         uint32_t idx;
 687         GElf_Ehdr ehdr;
 688         GElf_Shdr shdr;
 689         Elf_Data *syms, *opddata = NULL;
 690         GElf_Sym sym;
 691         Elf_Scn *sec, *sec_strndx;
 692         Elf *elf;
 693         int nr = 0;
 694         bool remap_kernel = false, adjust_kernel_syms = false;
 695
 696         dso->symtab_type = syms_ss->type;
 697         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 698
 699         /*
 700          * Modules may already have symbols from kallsyms, but those symbols
 701          * have the wrong values for the dso maps, so remove them.
 702          */
 703         if (kmodule && syms_ss->symtab)
 704                 symbols__delete(&dso->symbols[map->type]);
 705
 706         if (!syms_ss->symtab) {
 707                 syms_ss->symtab  = syms_ss->dynsym;
 708                 syms_ss->symshdr = syms_ss->dynshdr;
 709         }
 710
 711         elf = syms_ss->elf;
 712         ehdr = syms_ss->ehdr;
 713         sec = syms_ss->symtab;
 714         shdr = syms_ss->symshdr;
 715
 716         if (runtime_ss->opdsec)
 717                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 718
 719         syms = elf_getdata(sec, NULL);
 720         if (syms == NULL)
 721                 goto out_elf_end;
 722
 723         sec = elf_getscn(elf, shdr.sh_link);
 724         if (sec == NULL)
 725                 goto out_elf_end;
 726
 727         symstrs = elf_getdata(sec, NULL);
 728         if (symstrs == NULL)
 729                 goto out_elf_end;
 730
 731         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 732         if (sec_strndx == NULL)
 733                 goto out_elf_end;
 734
 735         secstrs = elf_getdata(sec_strndx, NULL);
 736         if (secstrs == NULL)
 737                 goto out_elf_end;
 738
 739         nr_syms = shdr.sh_size / shdr.sh_entsize;
 740
 741         memset(&sym, 0, sizeof(sym));
 742
 743         /*
 744          * The kernel relocation symbol is needed in advance in order to adjust
 745          * kernel maps correctly.
 746          */
 747         if (ref_reloc_sym_not_found(kmap)) {
 748                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 749                         const char *elf_name = elf_sym__name(&sym, symstrs);
 750
 751                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 752                                 continue;
 753                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 754                         map->reloc = kmap->ref_reloc_sym->addr -
 755                                      kmap->ref_reloc_sym->unrelocated_addr;
 756                         break;
 757                 }
 758         }
 759
 760         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 761         /*
 762          * Initial kernel and module mappings do not map to the dso.  For
 763          * function mappings, flag the fixups.
 764          */
 765         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 766                 remap_kernel = true;
 767                 adjust_kernel_syms = dso->adjust_symbols;
 768         }
 769         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 770                 struct symbol *f;
 771                 const char *elf_name = elf_sym__name(&sym, symstrs);
 772                 char *demangled = NULL;
 773                 int is_label = elf_sym__is_label(&sym);
 774                 const char *section_name;
 775                 bool used_opd = false;
 776
 777                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 778                         continue;
 779
 780                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 781                  * don't identify functions, so will confuse the profile
 782                  * output: */
 783                 if (ehdr.e_machine == EM_ARM) {
 784                         if (!strcmp(elf_name, "$a") ||
 785                             !strcmp(elf_name, "$d") ||
 786                             !strcmp(elf_name, "$t"))
 787                                 continue;
 788                 }
 789
 790                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 791                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 792                         u64 *opd = opddata->d_buf + offset;
 793                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 794                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 795                                         sym.st_value);
 796                         used_opd = true;
 797                 }
 798                 /*
 799                  * When loading symbols in a data mapping, ABS symbols (which
 800                  * has a value of SHN_ABS in its st_shndx) failed at
 801                  * elf_getscn().  And it marks the loading as a failure so
 802                  * already loaded symbols cannot be fixed up.
 803                  *
 804                  * I'm not sure what should be done. Just ignore them for now.
 805                  * - Namhyung Kim
 806                  */
 807                 if (sym.st_shndx == SHN_ABS)
 808                         continue;
 809
 810                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 811                 if (!sec)
 812                         goto out_elf_end;
 813
 814                 gelf_getshdr(sec, &shdr);
 815
 816                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 817                         continue;
 818
 819                 section_name = elf_sec__name(&shdr, secstrs);
 820
 821                 /* On ARM, symbols for thumb functions have 1 added to
 822                  * the symbol address as a flag - remove it */
 823                 if ((ehdr.e_machine == EM_ARM) &&
 824                     (map->type == MAP__FUNCTION) &&
 825                     (sym.st_value & 1))
 826                         --sym.st_value;
 827
 828                 if (dso->kernel || kmodule) {
 829                         char dso_name[PATH_MAX];
 830
 831                         /* Adjust symbol to map to file offset */
 832                         if (adjust_kernel_syms)
 833                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 834
 835                         if (strcmp(section_name,
 836                                    (curr_dso->short_name +
 837                                     dso->short_name_len)) == 0)
 838                                 goto new_symbol;
 839
 840                         if (strcmp(section_name, ".text") == 0) {
 841                                 /*
 842                                  * The initial kernel mapping is based on
 843                                  * kallsyms and identity maps.  Overwrite it to
 844                                  * map to the kernel dso.
 845                                  */
 846                                 if (remap_kernel && dso->kernel) {
 847                                         remap_kernel = false;
 848                                         map->start = shdr.sh_addr +
 849                                                      ref_reloc(kmap);
 850                                         map->end = map->start + shdr.sh_size;
 851                                         map->pgoff = shdr.sh_offset;
 852                                         map->map_ip = map__map_ip;
 853                                         map->unmap_ip = map__unmap_ip;
 854                                         /* Ensure maps are correctly ordered */
 855                                         map_groups__remove(kmap->kmaps, map);
 856                                         map_groups__insert(kmap->kmaps, map);
 857                                 }
 858
 859                                 /*
 860                                  * The initial module mapping is based on
 861                                  * /proc/modules mapped to offset zero.
 862                                  * Overwrite it to map to the module dso.
 863                                  */
 864                                 if (remap_kernel && kmodule) {
 865                                         remap_kernel = false;
 866                                         map->pgoff = shdr.sh_offset;
 867                                 }
 868
 869                                 curr_map = map;
 870                                 curr_dso = dso;
 871                                 goto new_symbol;
 872                         }
 873
 874                         if (!kmap)
 875                                 goto new_symbol;
 876
 877                         snprintf(dso_name, sizeof(dso_name),
 878                                  "%s%s", dso->short_name, section_name);
 879
 880                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 881                         if (curr_map == NULL) {
 882                                 u64 start = sym.st_value;
 883
 884                                 if (kmodule)
 885                                         start += map->start + shdr.sh_offset;
 886
 887                                 curr_dso = dso__new(dso_name);
 888                                 if (curr_dso == NULL)
 889                                         goto out_elf_end;
 890                                 curr_dso->kernel = dso->kernel;
 891                                 curr_dso->long_name = dso->long_name;
 892                                 curr_dso->long_name_len = dso->long_name_len;
 893                                 curr_map = map__new2(start, curr_dso,
 894                                                      map->type);
 895                                 if (curr_map == NULL) {
 896                                         dso__delete(curr_dso);
 897                                         goto out_elf_end;
 898                                 }
 899                                 if (adjust_kernel_syms) {
 900                                         curr_map->start = shdr.sh_addr +
 901                                                           ref_reloc(kmap);
 902                                         curr_map->end = curr_map->start +
 903                                                         shdr.sh_size;
 904                                         curr_map->pgoff = shdr.sh_offset;
 905                                 } else {
 906                                         curr_map->map_ip = identity__map_ip;
 907                                         curr_map->unmap_ip = identity__map_ip;
 908                                 }
 909                                 curr_dso->symtab_type = dso->symtab_type;
 910                                 map_groups__insert(kmap->kmaps, curr_map);
 911                                 dsos__add(&dso->node, curr_dso);
 912                                 dso__set_loaded(curr_dso, map->type);
 913                         } else
 914                                 curr_dso = curr_map->dso;
 915
 916                         goto new_symbol;
 917                 }
 918
 919                 if ((used_opd && runtime_ss->adjust_symbols)
 920                                 || (!used_opd && syms_ss->adjust_symbols)) {
 921                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 922                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 923                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 924                                   (u64)shdr.sh_offset);
 925                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 926                 }
 927 new_symbol:
 928                 /*
 929                  * We need to figure out if the object was created from C++ sources
 930                  * DWARF DW_compile_unit has this, but we don't always have access
 931                  * to it...
 932                  */
 933                 if (symbol_conf.demangle) {
 934                         demangled = bfd_demangle(NULL, elf_name,
 935                                                  DMGL_PARAMS | DMGL_ANSI);
 936                         if (demangled != NULL)
 937                                 elf_name = demangled;
 938                 }
 939                 f = symbol__new(sym.st_value, sym.st_size,
 940                                 GELF_ST_BIND(sym.st_info), elf_name);
 941                 free(demangled);
 942                 if (!f)
 943                         goto out_elf_end;
 944
 945                 if (filter && filter(curr_map, f))
 946                         symbol__delete(f);
 947                 else {
 948                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
 949                         nr++;
 950                 }
 951         }
 952
 953         /*
 954          * For misannotated, zeroed, ASM function sizes.
 955          */
 956         if (nr > 0) {
 957                 symbols__fixup_duplicate(&dso->symbols[map->type]);
 958                 symbols__fixup_end(&dso->symbols[map->type]);
 959                 if (kmap) {
 960                         /*
 961                          * We need to fixup this here too because we create new
 962                          * maps here, for things like vsyscall sections.
 963                          */
 964                         __map_groups__fixup_end(kmap->kmaps, map->type);
 965                 }
 966         }
 967         err = nr;
 968 out_elf_end:
 969         return err;
 970 }
 971
 972 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
 973 {
 974         GElf_Phdr phdr;
 975         size_t i, phdrnum;
 976         int err;
 977         u64 sz;
 978
 979         if (elf_getphdrnum(elf, &phdrnum))
 980                 return -1;
 981
 982         for (i = 0; i < phdrnum; i++) {
 983                 if (gelf_getphdr(elf, i, &phdr) == NULL)
 984                         return -1;
 985                 if (phdr.p_type != PT_LOAD)
 986                         continue;
 987                 if (exe) {
 988                         if (!(phdr.p_flags & PF_X))
 989                                 continue;
 990                 } else {
 991                         if (!(phdr.p_flags & PF_R))
 992                                 continue;
 993                 }
 994                 sz = min(phdr.p_memsz, phdr.p_filesz);
 995                 if (!sz)
 996                         continue;
 997                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
 998                 if (err)
 999                         return err;
1000         }
1001         return 0;
1002 }
1003
1004 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1005                     bool *is_64_bit)
1006 {
1007         int err;
1008         Elf *elf;
1009
1010         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1011         if (elf == NULL)
1012                 return -1;
1013
1014         if (is_64_bit)
1015                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1016
1017         err = elf_read_maps(elf, exe, mapfn, data);
1018
1019         elf_end(elf);
1020         return err;
1021 }
1022
1023 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1024 {
1025         ssize_t r;
1026         size_t n;
1027         int err = -1;
1028         char *buf = malloc(page_size);
1029
1030         if (buf == NULL)
1031                 return -1;
1032
1033         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1034                 goto out;
1035
1036         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1037                 goto out;
1038
1039         while (len) {
1040                 n = page_size;
1041                 if (len < n)
1042                         n = len;
1043                 /* Use read because mmap won't work on proc files */
1044                 r = read(from, buf, n);
1045                 if (r < 0)
1046                         goto out;
1047                 if (!r)
1048                         break;
1049                 n = r;
1050                 r = write(to, buf, n);
1051                 if (r < 0)
1052                         goto out;
1053                 if ((size_t)r != n)
1054                         goto out;
1055                 len -= n;
1056         }
1057
1058         err = 0;
1059 out:
1060         free(buf);
1061         return err;
1062 }
1063
1064 struct kcore {
1065         int fd;
1066         int elfclass;
1067         Elf *elf;
1068         GElf_Ehdr ehdr;
1069 };
1070
1071 static int kcore__open(struct kcore *kcore, const char *filename)
1072 {
1073         GElf_Ehdr *ehdr;
1074
1075         kcore->fd = open(filename, O_RDONLY);
1076         if (kcore->fd == -1)
1077                 return -1;
1078
1079         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1080         if (!kcore->elf)
1081                 goto out_close;
1082
1083         kcore->elfclass = gelf_getclass(kcore->elf);
1084         if (kcore->elfclass == ELFCLASSNONE)
1085                 goto out_end;
1086
1087         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1088         if (!ehdr)
1089                 goto out_end;
1090
1091         return 0;
1092
1093 out_end:
1094         elf_end(kcore->elf);
1095 out_close:
1096         close(kcore->fd);
1097         return -1;
1098 }
1099
1100 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1101                        bool temp)
1102 {
1103         GElf_Ehdr *ehdr;
1104
1105         kcore->elfclass = elfclass;
1106
1107         if (temp)
1108                 kcore->fd = mkstemp(filename);
1109         else
1110                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1111         if (kcore->fd == -1)
1112                 return -1;
1113
1114         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1115         if (!kcore->elf)
1116                 goto out_close;
1117
1118         if (!gelf_newehdr(kcore->elf, elfclass))
1119                 goto out_end;
1120
1121         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1122         if (!ehdr)
1123                 goto out_end;
1124
1125         return 0;
1126
1127 out_end:
1128         elf_end(kcore->elf);
1129 out_close:
1130         close(kcore->fd);
1131         unlink(filename);
1132         return -1;
1133 }
1134
1135 static void kcore__close(struct kcore *kcore)
1136 {
1137         elf_end(kcore->elf);
1138         close(kcore->fd);
1139 }
1140
1141 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1142 {
1143         GElf_Ehdr *ehdr = &to->ehdr;
1144         GElf_Ehdr *kehdr = &from->ehdr;
1145
1146         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1147         ehdr->e_type      = kehdr->e_type;
1148         ehdr->e_machine   = kehdr->e_machine;
1149         ehdr->e_version   = kehdr->e_version;
1150         ehdr->e_entry     = 0;
1151         ehdr->e_shoff     = 0;
1152         ehdr->e_flags     = kehdr->e_flags;
1153         ehdr->e_phnum     = count;
1154         ehdr->e_shentsize = 0;
1155         ehdr->e_shnum     = 0;
1156         ehdr->e_shstrndx  = 0;
1157
1158         if (from->elfclass == ELFCLASS32) {
1159                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1160                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1161                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1162         } else {
1163                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1164                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1165                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1166         }
1167
1168         if (!gelf_update_ehdr(to->elf, ehdr))
1169                 return -1;
1170
1171         if (!gelf_newphdr(to->elf, count))
1172                 return -1;
1173
1174         return 0;
1175 }
1176
1177 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1178                            u64 addr, u64 len)
1179 {
1180         GElf_Phdr gphdr;
1181         GElf_Phdr *phdr;
1182
1183         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1184         if (!phdr)
1185                 return -1;
1186
1187         phdr->p_type    = PT_LOAD;
1188         phdr->p_flags   = PF_R | PF_W | PF_X;
1189         phdr->p_offset  = offset;
1190         phdr->p_vaddr   = addr;
1191         phdr->p_paddr   = 0;
1192         phdr->p_filesz  = len;
1193         phdr->p_memsz   = len;
1194         phdr->p_align   = page_size;
1195
1196         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1197                 return -1;
1198
1199         return 0;
1200 }
1201
1202 static off_t kcore__write(struct kcore *kcore)
1203 {
1204         return elf_update(kcore->elf, ELF_C_WRITE);
1205 }
1206
1207 struct phdr_data {
1208         off_t offset;
1209         u64 addr;
1210         u64 len;
1211 };
1212
1213 struct kcore_copy_info {
1214         u64 stext;
1215         u64 etext;
1216         u64 first_symbol;
1217         u64 last_symbol;
1218         u64 first_module;
1219         u64 last_module_symbol;
1220         struct phdr_data kernel_map;
1221         struct phdr_data modules_map;
1222 };
1223
1224 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1225                                         u64 start)
1226 {
1227         struct kcore_copy_info *kci = arg;
1228
1229         if (!symbol_type__is_a(type, MAP__FUNCTION))
1230                 return 0;
1231
1232         if (strchr(name, '[')) {
1233                 if (start > kci->last_module_symbol)
1234                         kci->last_module_symbol = start;
1235                 return 0;
1236         }
1237
1238         if (!kci->first_symbol || start < kci->first_symbol)
1239                 kci->first_symbol = start;
1240
1241         if (!kci->last_symbol || start > kci->last_symbol)
1242                 kci->last_symbol = start;
1243
1244         if (!strcmp(name, "_stext")) {
1245                 kci->stext = start;
1246                 return 0;
1247         }
1248
1249         if (!strcmp(name, "_etext")) {
1250                 kci->etext = start;
1251                 return 0;
1252         }
1253
1254         return 0;
1255 }
1256
1257 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1258                                       const char *dir)
1259 {
1260         char kallsyms_filename[PATH_MAX];
1261
1262         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1263
1264         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1265                 return -1;
1266
1267         if (kallsyms__parse(kallsyms_filename, kci,
1268                             kcore_copy__process_kallsyms) < 0)
1269                 return -1;
1270
1271         return 0;
1272 }
1273
1274 static int kcore_copy__process_modules(void *arg,
1275                                        const char *name __maybe_unused,
1276                                        u64 start)
1277 {
1278         struct kcore_copy_info *kci = arg;
1279
1280         if (!kci->first_module || start < kci->first_module)
1281                 kci->first_module = start;
1282
1283         return 0;
1284 }
1285
1286 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1287                                      const char *dir)
1288 {
1289         char modules_filename[PATH_MAX];
1290
1291         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1292
1293         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1294                 return -1;
1295
1296         if (modules__parse(modules_filename, kci,
1297                            kcore_copy__process_modules) < 0)
1298                 return -1;
1299
1300         return 0;
1301 }
1302
1303 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1304                             u64 s, u64 e)
1305 {
1306         if (p->addr || s < start || s >= end)
1307                 return;
1308
1309         p->addr = s;
1310         p->offset = (s - start) + pgoff;
1311         p->len = e < end ? e - s : end - s;
1312 }
1313
1314 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1315 {
1316         struct kcore_copy_info *kci = data;
1317         u64 end = start + len;
1318
1319         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1320                         kci->etext);
1321
1322         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1323                         kci->last_module_symbol);
1324
1325         return 0;
1326 }
1327
1328 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1329 {
1330         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1331                 return -1;
1332
1333         return 0;
1334 }
1335
1336 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1337                                  Elf *elf)
1338 {
1339         if (kcore_copy__parse_kallsyms(kci, dir))
1340                 return -1;
1341
1342         if (kcore_copy__parse_modules(kci, dir))
1343                 return -1;
1344
1345         if (kci->stext)
1346                 kci->stext = round_down(kci->stext, page_size);
1347         else
1348                 kci->stext = round_down(kci->first_symbol, page_size);
1349
1350         if (kci->etext) {
1351                 kci->etext = round_up(kci->etext, page_size);
1352         } else if (kci->last_symbol) {
1353                 kci->etext = round_up(kci->last_symbol, page_size);
1354                 kci->etext += page_size;
1355         }
1356
1357         kci->first_module = round_down(kci->first_module, page_size);
1358
1359         if (kci->last_module_symbol) {
1360                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1361                                                    page_size);
1362                 kci->last_module_symbol += page_size;
1363         }
1364
1365         if (!kci->stext || !kci->etext)
1366                 return -1;
1367
1368         if (kci->first_module && !kci->last_module_symbol)
1369                 return -1;
1370
1371         return kcore_copy__read_maps(kci, elf);
1372 }
1373
1374 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1375                                  const char *name)
1376 {
1377         char from_filename[PATH_MAX];
1378         char to_filename[PATH_MAX];
1379
1380         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1381         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1382
1383         return copyfile_mode(from_filename, to_filename, 0400);
1384 }
1385
1386 static int kcore_copy__unlink(const char *dir, const char *name)
1387 {
1388         char filename[PATH_MAX];
1389
1390         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1391
1392         return unlink(filename);
1393 }
1394
1395 static int kcore_copy__compare_fds(int from, int to)
1396 {
1397         char *buf_from;
1398         char *buf_to;
1399         ssize_t ret;
1400         size_t len;
1401         int err = -1;
1402
1403         buf_from = malloc(page_size);
1404         buf_to = malloc(page_size);
1405         if (!buf_from || !buf_to)
1406                 goto out;
1407
1408         while (1) {
1409                 /* Use read because mmap won't work on proc files */
1410                 ret = read(from, buf_from, page_size);
1411                 if (ret < 0)
1412                         goto out;
1413
1414                 if (!ret)
1415                         break;
1416
1417                 len = ret;
1418
1419                 if (readn(to, buf_to, len) != (int)len)
1420                         goto out;
1421
1422                 if (memcmp(buf_from, buf_to, len))
1423                         goto out;
1424         }
1425
1426         err = 0;
1427 out:
1428         free(buf_to);
1429         free(buf_from);
1430         return err;
1431 }
1432
1433 static int kcore_copy__compare_files(const char *from_filename,
1434                                      const char *to_filename)
1435 {
1436         int from, to, err = -1;
1437
1438         from = open(from_filename, O_RDONLY);
1439         if (from < 0)
1440                 return -1;
1441
1442         to = open(to_filename, O_RDONLY);
1443         if (to < 0)
1444                 goto out_close_from;
1445
1446         err = kcore_copy__compare_fds(from, to);
1447
1448         close(to);
1449 out_close_from:
1450         close(from);
1451         return err;
1452 }
1453
1454 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1455                                     const char *name)
1456 {
1457         char from_filename[PATH_MAX];
1458         char to_filename[PATH_MAX];
1459
1460         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1461         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1462
1463         return kcore_copy__compare_files(from_filename, to_filename);
1464 }
1465
1466 /**
1467  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1468  * @from_dir: from directory
1469  * @to_dir: to directory
1470  *
1471  * This function copies kallsyms, modules and kcore files from one directory to
1472  * another.  kallsyms and modules are copied entirely.  Only code segments are
1473  * copied from kcore.  It is assumed that two segments suffice: one for the
1474  * kernel proper and one for all the modules.  The code segments are determined
1475  * from kallsyms and modules files.  The kernel map starts at _stext or the
1476  * lowest function symbol, and ends at _etext or the highest function symbol.
1477  * The module map starts at the lowest module address and ends at the highest
1478  * module symbol.  Start addresses are rounded down to the nearest page.  End
1479  * addresses are rounded up to the nearest page.  An extra page is added to the
1480  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1481  * symbol too.  Because it contains only code sections, the resulting kcore is
1482  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1483  * is not the same for the kernel map and the modules map.  That happens because
1484  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1485  * kallsyms and modules files are compared with their copies to check that
1486  * modules have not been loaded or unloaded while the copies were taking place.
1487  *
1488  * Return: %0 on success, %-1 on failure.
1489  */
1490 int kcore_copy(const char *from_dir, const char *to_dir)
1491 {
1492         struct kcore kcore;
1493         struct kcore extract;
1494         size_t count = 2;
1495         int idx = 0, err = -1;
1496         off_t offset = page_size, sz, modules_offset = 0;
1497         struct kcore_copy_info kci = { .stext = 0, };
1498         char kcore_filename[PATH_MAX];
1499         char extract_filename[PATH_MAX];
1500
1501         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1502                 return -1;
1503
1504         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1505                 goto out_unlink_kallsyms;
1506
1507         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1508         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1509
1510         if (kcore__open(&kcore, kcore_filename))
1511                 goto out_unlink_modules;
1512
1513         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1514                 goto out_kcore_close;
1515
1516         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1517                 goto out_kcore_close;
1518
1519         if (!kci.modules_map.addr)
1520                 count -= 1;
1521
1522         if (kcore__copy_hdr(&kcore, &extract, count))
1523                 goto out_extract_close;
1524
1525         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1526                             kci.kernel_map.len))
1527                 goto out_extract_close;
1528
1529         if (kci.modules_map.addr) {
1530                 modules_offset = offset + kci.kernel_map.len;
1531                 if (kcore__add_phdr(&extract, idx, modules_offset,
1532                                     kci.modules_map.addr, kci.modules_map.len))
1533                         goto out_extract_close;
1534         }
1535
1536         sz = kcore__write(&extract);
1537         if (sz < 0 || sz > offset)
1538                 goto out_extract_close;
1539
1540         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1541                        kci.kernel_map.len))
1542                 goto out_extract_close;
1543
1544         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1545                                          extract.fd, modules_offset,
1546                                          kci.modules_map.len))
1547                 goto out_extract_close;
1548
1549         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1550                 goto out_extract_close;
1551
1552         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1553                 goto out_extract_close;
1554
1555         err = 0;
1556
1557 out_extract_close:
1558         kcore__close(&extract);
1559         if (err)
1560                 unlink(extract_filename);
1561 out_kcore_close:
1562         kcore__close(&kcore);
1563 out_unlink_modules:
1564         if (err)
1565                 kcore_copy__unlink(to_dir, "modules");
1566 out_unlink_kallsyms:
1567         if (err)
1568                 kcore_copy__unlink(to_dir, "kallsyms");
1569
1570         return err;
1571 }
1572
1573 int kcore_extract__create(struct kcore_extract *kce)
1574 {
1575         struct kcore kcore;
1576         struct kcore extract;
1577         size_t count = 1;
1578         int idx = 0, err = -1;
1579         off_t offset = page_size, sz;
1580
1581         if (kcore__open(&kcore, kce->kcore_filename))
1582                 return -1;
1583
1584         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1585         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1586                 goto out_kcore_close;
1587
1588         if (kcore__copy_hdr(&kcore, &extract, count))
1589                 goto out_extract_close;
1590
1591         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1592                 goto out_extract_close;
1593
1594         sz = kcore__write(&extract);
1595         if (sz < 0 || sz > offset)
1596                 goto out_extract_close;
1597
1598         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1599                 goto out_extract_close;
1600
1601         err = 0;
1602
1603 out_extract_close:
1604         kcore__close(&extract);
1605         if (err)
1606                 unlink(kce->extract_filename);
1607 out_kcore_close:
1608         kcore__close(&kcore);
1609
1610         return err;
1611 }
1612
1613 void kcore_extract__delete(struct kcore_extract *kce)
1614 {
1615         unlink(kce->extract_filename);
1616 }
1617
1618 void symbol__elf_init(void)
1619 {
1620         elf_version(EV_CURRENT);
1621 }