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 (str && !strcmp(name, str)) {
 155                         if (idx)
 156                                 *idx = cnt;
 157                         return sec;
 158                 }
 159                 ++cnt;
 160         }
 161
 162         return NULL;
 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         err = 0;
 510
 511 out_elf_end:
 512         elf_end(elf);
 513 out_close:
 514         close(fd);
 515 out:
 516         return err;
 517 }
 518
 519 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 520 {
 521         static unsigned int const endian = 1;
 522
 523         dso->needs_swap = DSO_SWAP__NO;
 524
 525         switch (eidata) {
 526         case ELFDATA2LSB:
 527                 /* We are big endian, DSO is little endian. */
 528                 if (*(unsigned char const *)&endian != 1)
 529                         dso->needs_swap = DSO_SWAP__YES;
 530                 break;
 531
 532         case ELFDATA2MSB:
 533                 /* We are little endian, DSO is big endian. */
 534                 if (*(unsigned char const *)&endian != 0)
 535                         dso->needs_swap = DSO_SWAP__YES;
 536                 break;
 537
 538         default:
 539                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 540                 return -EINVAL;
 541         }
 542
 543         return 0;
 544 }
 545
 546 bool symsrc__possibly_runtime(struct symsrc *ss)
 547 {
 548         return ss->dynsym || ss->opdsec;
 549 }
 550
 551 bool symsrc__has_symtab(struct symsrc *ss)
 552 {
 553         return ss->symtab != NULL;
 554 }
 555
 556 void symsrc__destroy(struct symsrc *ss)
 557 {
 558         zfree(&ss->name);
 559         elf_end(ss->elf);
 560         close(ss->fd);
 561 }
 562
 563 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 564                  enum dso_binary_type type)
 565 {
 566         int err = -1;
 567         GElf_Ehdr ehdr;
 568         Elf *elf;
 569         int fd;
 570
 571         fd = open(name, O_RDONLY);
 572         if (fd < 0)
 573                 return -1;
 574
 575         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 576         if (elf == NULL) {
 577                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 578                 goto out_close;
 579         }
 580
 581         if (gelf_getehdr(elf, &ehdr) == NULL) {
 582                 pr_debug("%s: cannot get elf header.\n", __func__);
 583                 goto out_elf_end;
 584         }
 585
 586         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 587                 goto out_elf_end;
 588
 589         /* Always reject images with a mismatched build-id: */
 590         if (dso->has_build_id) {
 591                 u8 build_id[BUILD_ID_SIZE];
 592
 593                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 594                         goto out_elf_end;
 595
 596                 if (!dso__build_id_equal(dso, build_id))
 597                         goto out_elf_end;
 598         }
 599
 600         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 601                         NULL);
 602         if (ss->symshdr.sh_type != SHT_SYMTAB)
 603                 ss->symtab = NULL;
 604
 605         ss->dynsym_idx = 0;
 606         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 607                         &ss->dynsym_idx);
 608         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 609                 ss->dynsym = NULL;
 610
 611         ss->opdidx = 0;
 612         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 613                         &ss->opdidx);
 614         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 615                 ss->opdsec = NULL;
 616
 617         if (dso->kernel == DSO_TYPE_USER) {
 618                 GElf_Shdr shdr;
 619                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 620                                 ehdr.e_type == ET_REL ||
 621                                 elf_section_by_name(elf, &ehdr, &shdr,
 622                                                      ".gnu.prelink_undo",
 623                                                      NULL) != NULL);
 624         } else {
 625                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 626                                      ehdr.e_type == ET_REL;
 627         }
 628
 629         ss->name   = strdup(name);
 630         if (!ss->name)
 631                 goto out_elf_end;
 632
 633         ss->elf    = elf;
 634         ss->fd     = fd;
 635         ss->ehdr   = ehdr;
 636         ss->type   = type;
 637
 638         return 0;
 639
 640 out_elf_end:
 641         elf_end(elf);
 642 out_close:
 643         close(fd);
 644         return err;
 645 }
 646
 647 /**
 648  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 649  * @kmap: kernel maps and relocation reference symbol
 650  *
 651  * This function returns %true if we are dealing with the kernel maps and the
 652  * relocation reference symbol has not yet been found.  Otherwise %false is
 653  * returned.
 654  */
 655 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 656 {
 657         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 658                !kmap->ref_reloc_sym->unrelocated_addr;
 659 }
 660
 661 /**
 662  * ref_reloc - kernel relocation offset.
 663  * @kmap: kernel maps and relocation reference symbol
 664  *
 665  * This function returns the offset of kernel addresses as determined by using
 666  * the relocation reference symbol i.e. if the kernel has not been relocated
 667  * then the return value is zero.
 668  */
 669 static u64 ref_reloc(struct kmap *kmap)
 670 {
 671         if (kmap && kmap->ref_reloc_sym &&
 672             kmap->ref_reloc_sym->unrelocated_addr)
 673                 return kmap->ref_reloc_sym->addr -
 674                        kmap->ref_reloc_sym->unrelocated_addr;
 675         return 0;
 676 }
 677
 678 int dso__load_sym(struct dso *dso, struct map *map,
 679                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 680                   symbol_filter_t filter, int kmodule)
 681 {
 682         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 683         struct map *curr_map = map;
 684         struct dso *curr_dso = dso;
 685         Elf_Data *symstrs, *secstrs;
 686         uint32_t nr_syms;
 687         int err = -1;
 688         uint32_t idx;
 689         GElf_Ehdr ehdr;
 690         GElf_Shdr shdr;
 691         Elf_Data *syms, *opddata = NULL;
 692         GElf_Sym sym;
 693         Elf_Scn *sec, *sec_strndx;
 694         Elf *elf;
 695         int nr = 0;
 696         bool remap_kernel = false, adjust_kernel_syms = false;
 697
 698         dso->symtab_type = syms_ss->type;
 699         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 700
 701         /*
 702          * Modules may already have symbols from kallsyms, but those symbols
 703          * have the wrong values for the dso maps, so remove them.
 704          */
 705         if (kmodule && syms_ss->symtab)
 706                 symbols__delete(&dso->symbols[map->type]);
 707
 708         if (!syms_ss->symtab) {
 709                 syms_ss->symtab  = syms_ss->dynsym;
 710                 syms_ss->symshdr = syms_ss->dynshdr;
 711         }
 712
 713         elf = syms_ss->elf;
 714         ehdr = syms_ss->ehdr;
 715         sec = syms_ss->symtab;
 716         shdr = syms_ss->symshdr;
 717
 718         if (runtime_ss->opdsec)
 719                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 720
 721         syms = elf_getdata(sec, NULL);
 722         if (syms == NULL)
 723                 goto out_elf_end;
 724
 725         sec = elf_getscn(elf, shdr.sh_link);
 726         if (sec == NULL)
 727                 goto out_elf_end;
 728
 729         symstrs = elf_getdata(sec, NULL);
 730         if (symstrs == NULL)
 731                 goto out_elf_end;
 732
 733         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 734         if (sec_strndx == NULL)
 735                 goto out_elf_end;
 736
 737         secstrs = elf_getdata(sec_strndx, NULL);
 738         if (secstrs == NULL)
 739                 goto out_elf_end;
 740
 741         nr_syms = shdr.sh_size / shdr.sh_entsize;
 742
 743         memset(&sym, 0, sizeof(sym));
 744
 745         /*
 746          * The kernel relocation symbol is needed in advance in order to adjust
 747          * kernel maps correctly.
 748          */
 749         if (ref_reloc_sym_not_found(kmap)) {
 750                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 751                         const char *elf_name = elf_sym__name(&sym, symstrs);
 752
 753                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 754                                 continue;
 755                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 756                         map->reloc = kmap->ref_reloc_sym->addr -
 757                                      kmap->ref_reloc_sym->unrelocated_addr;
 758                         break;
 759                 }
 760         }
 761
 762         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 763         /*
 764          * Initial kernel and module mappings do not map to the dso.  For
 765          * function mappings, flag the fixups.
 766          */
 767         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 768                 remap_kernel = true;
 769                 adjust_kernel_syms = dso->adjust_symbols;
 770         }
 771         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 772                 struct symbol *f;
 773                 const char *elf_name = elf_sym__name(&sym, symstrs);
 774                 char *demangled = NULL;
 775                 int is_label = elf_sym__is_label(&sym);
 776                 const char *section_name;
 777                 bool used_opd = false;
 778
 779                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 780                         continue;
 781
 782                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 783                  * don't identify functions, so will confuse the profile
 784                  * output: */
 785                 if (ehdr.e_machine == EM_ARM) {
 786                         if (!strcmp(elf_name, "$a") ||
 787                             !strcmp(elf_name, "$d") ||
 788                             !strcmp(elf_name, "$t"))
 789                                 continue;
 790                 }
 791
 792                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 793                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 794                         u64 *opd = opddata->d_buf + offset;
 795                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 796                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 797                                         sym.st_value);
 798                         used_opd = true;
 799                 }
 800                 /*
 801                  * When loading symbols in a data mapping, ABS symbols (which
 802                  * has a value of SHN_ABS in its st_shndx) failed at
 803                  * elf_getscn().  And it marks the loading as a failure so
 804                  * already loaded symbols cannot be fixed up.
 805                  *
 806                  * I'm not sure what should be done. Just ignore them for now.
 807                  * - Namhyung Kim
 808                  */
 809                 if (sym.st_shndx == SHN_ABS)
 810                         continue;
 811
 812                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 813                 if (!sec)
 814                         goto out_elf_end;
 815
 816                 gelf_getshdr(sec, &shdr);
 817
 818                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 819                         continue;
 820
 821                 section_name = elf_sec__name(&shdr, secstrs);
 822
 823                 /* On ARM, symbols for thumb functions have 1 added to
 824                  * the symbol address as a flag - remove it */
 825                 if ((ehdr.e_machine == EM_ARM) &&
 826                     (map->type == MAP__FUNCTION) &&
 827                     (sym.st_value & 1))
 828                         --sym.st_value;
 829
 830                 if (dso->kernel || kmodule) {
 831                         char dso_name[PATH_MAX];
 832
 833                         /* Adjust symbol to map to file offset */
 834                         if (adjust_kernel_syms)
 835                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 836
 837                         if (strcmp(section_name,
 838                                    (curr_dso->short_name +
 839                                     dso->short_name_len)) == 0)
 840                                 goto new_symbol;
 841
 842                         if (strcmp(section_name, ".text") == 0) {
 843                                 /*
 844                                  * The initial kernel mapping is based on
 845                                  * kallsyms and identity maps.  Overwrite it to
 846                                  * map to the kernel dso.
 847                                  */
 848                                 if (remap_kernel && dso->kernel) {
 849                                         remap_kernel = false;
 850                                         map->start = shdr.sh_addr +
 851                                                      ref_reloc(kmap);
 852                                         map->end = map->start + shdr.sh_size;
 853                                         map->pgoff = shdr.sh_offset;
 854                                         map->map_ip = map__map_ip;
 855                                         map->unmap_ip = map__unmap_ip;
 856                                         /* Ensure maps are correctly ordered */
 857                                         map_groups__remove(kmap->kmaps, map);
 858                                         map_groups__insert(kmap->kmaps, map);
 859                                 }
 860
 861                                 /*
 862                                  * The initial module mapping is based on
 863                                  * /proc/modules mapped to offset zero.
 864                                  * Overwrite it to map to the module dso.
 865                                  */
 866                                 if (remap_kernel && kmodule) {
 867                                         remap_kernel = false;
 868                                         map->pgoff = shdr.sh_offset;
 869                                 }
 870
 871                                 curr_map = map;
 872                                 curr_dso = dso;
 873                                 goto new_symbol;
 874                         }
 875
 876                         if (!kmap)
 877                                 goto new_symbol;
 878
 879                         snprintf(dso_name, sizeof(dso_name),
 880                                  "%s%s", dso->short_name, section_name);
 881
 882                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 883                         if (curr_map == NULL) {
 884                                 u64 start = sym.st_value;
 885
 886                                 if (kmodule)
 887                                         start += map->start + shdr.sh_offset;
 888
 889                                 curr_dso = dso__new(dso_name);
 890                                 if (curr_dso == NULL)
 891                                         goto out_elf_end;
 892                                 curr_dso->kernel = dso->kernel;
 893                                 curr_dso->long_name = dso->long_name;
 894                                 curr_dso->long_name_len = dso->long_name_len;
 895                                 curr_map = map__new2(start, curr_dso,
 896                                                      map->type);
 897                                 if (curr_map == NULL) {
 898                                         dso__delete(curr_dso);
 899                                         goto out_elf_end;
 900                                 }
 901                                 if (adjust_kernel_syms) {
 902                                         curr_map->start = shdr.sh_addr +
 903                                                           ref_reloc(kmap);
 904                                         curr_map->end = curr_map->start +
 905                                                         shdr.sh_size;
 906                                         curr_map->pgoff = shdr.sh_offset;
 907                                 } else {
 908                                         curr_map->map_ip = identity__map_ip;
 909                                         curr_map->unmap_ip = identity__map_ip;
 910                                 }
 911                                 curr_dso->symtab_type = dso->symtab_type;
 912                                 map_groups__insert(kmap->kmaps, curr_map);
 913                                 dsos__add(&dso->node, curr_dso);
 914                                 dso__set_loaded(curr_dso, map->type);
 915                         } else
 916                                 curr_dso = curr_map->dso;
 917
 918                         goto new_symbol;
 919                 }
 920
 921                 if ((used_opd && runtime_ss->adjust_symbols)
 922                                 || (!used_opd && syms_ss->adjust_symbols)) {
 923                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 924                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 925                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 926                                   (u64)shdr.sh_offset);
 927                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 928                 }
 929 new_symbol:
 930                 /*
 931                  * We need to figure out if the object was created from C++ sources
 932                  * DWARF DW_compile_unit has this, but we don't always have access
 933                  * to it...
 934                  */
 935                 if (symbol_conf.demangle) {
 936                         demangled = bfd_demangle(NULL, elf_name,
 937                                                  DMGL_PARAMS | DMGL_ANSI);
 938                         if (demangled != NULL)
 939                                 elf_name = demangled;
 940                 }
 941                 f = symbol__new(sym.st_value, sym.st_size,
 942                                 GELF_ST_BIND(sym.st_info), elf_name);
 943                 free(demangled);
 944                 if (!f)
 945                         goto out_elf_end;
 946
 947                 if (filter && filter(curr_map, f))
 948                         symbol__delete(f);
 949                 else {
 950                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
 951                         nr++;
 952                 }
 953         }
 954
 955         /*
 956          * For misannotated, zeroed, ASM function sizes.
 957          */
 958         if (nr > 0) {
 959                 symbols__fixup_duplicate(&dso->symbols[map->type]);
 960                 symbols__fixup_end(&dso->symbols[map->type]);
 961                 if (kmap) {
 962                         /*
 963                          * We need to fixup this here too because we create new
 964                          * maps here, for things like vsyscall sections.
 965                          */
 966                         __map_groups__fixup_end(kmap->kmaps, map->type);
 967                 }
 968         }
 969         err = nr;
 970 out_elf_end:
 971         return err;
 972 }
 973
 974 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
 975 {
 976         GElf_Phdr phdr;
 977         size_t i, phdrnum;
 978         int err;
 979         u64 sz;
 980
 981         if (elf_getphdrnum(elf, &phdrnum))
 982                 return -1;
 983
 984         for (i = 0; i < phdrnum; i++) {
 985                 if (gelf_getphdr(elf, i, &phdr) == NULL)
 986                         return -1;
 987                 if (phdr.p_type != PT_LOAD)
 988                         continue;
 989                 if (exe) {
 990                         if (!(phdr.p_flags & PF_X))
 991                                 continue;
 992                 } else {
 993                         if (!(phdr.p_flags & PF_R))
 994                                 continue;
 995                 }
 996                 sz = min(phdr.p_memsz, phdr.p_filesz);
 997                 if (!sz)
 998                         continue;
 999                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1000                 if (err)
1001                         return err;
1002         }
1003         return 0;
1004 }
1005
1006 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1007                     bool *is_64_bit)
1008 {
1009         int err;
1010         Elf *elf;
1011
1012         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1013         if (elf == NULL)
1014                 return -1;
1015
1016         if (is_64_bit)
1017                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1018
1019         err = elf_read_maps(elf, exe, mapfn, data);
1020
1021         elf_end(elf);
1022         return err;
1023 }
1024
1025 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1026 {
1027         ssize_t r;
1028         size_t n;
1029         int err = -1;
1030         char *buf = malloc(page_size);
1031
1032         if (buf == NULL)
1033                 return -1;
1034
1035         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1036                 goto out;
1037
1038         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1039                 goto out;
1040
1041         while (len) {
1042                 n = page_size;
1043                 if (len < n)
1044                         n = len;
1045                 /* Use read because mmap won't work on proc files */
1046                 r = read(from, buf, n);
1047                 if (r < 0)
1048                         goto out;
1049                 if (!r)
1050                         break;
1051                 n = r;
1052                 r = write(to, buf, n);
1053                 if (r < 0)
1054                         goto out;
1055                 if ((size_t)r != n)
1056                         goto out;
1057                 len -= n;
1058         }
1059
1060         err = 0;
1061 out:
1062         free(buf);
1063         return err;
1064 }
1065
1066 struct kcore {
1067         int fd;
1068         int elfclass;
1069         Elf *elf;
1070         GElf_Ehdr ehdr;
1071 };
1072
1073 static int kcore__open(struct kcore *kcore, const char *filename)
1074 {
1075         GElf_Ehdr *ehdr;
1076
1077         kcore->fd = open(filename, O_RDONLY);
1078         if (kcore->fd == -1)
1079                 return -1;
1080
1081         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1082         if (!kcore->elf)
1083                 goto out_close;
1084
1085         kcore->elfclass = gelf_getclass(kcore->elf);
1086         if (kcore->elfclass == ELFCLASSNONE)
1087                 goto out_end;
1088
1089         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1090         if (!ehdr)
1091                 goto out_end;
1092
1093         return 0;
1094
1095 out_end:
1096         elf_end(kcore->elf);
1097 out_close:
1098         close(kcore->fd);
1099         return -1;
1100 }
1101
1102 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1103                        bool temp)
1104 {
1105         GElf_Ehdr *ehdr;
1106
1107         kcore->elfclass = elfclass;
1108
1109         if (temp)
1110                 kcore->fd = mkstemp(filename);
1111         else
1112                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1113         if (kcore->fd == -1)
1114                 return -1;
1115
1116         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1117         if (!kcore->elf)
1118                 goto out_close;
1119
1120         if (!gelf_newehdr(kcore->elf, elfclass))
1121                 goto out_end;
1122
1123         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1124         if (!ehdr)
1125                 goto out_end;
1126
1127         return 0;
1128
1129 out_end:
1130         elf_end(kcore->elf);
1131 out_close:
1132         close(kcore->fd);
1133         unlink(filename);
1134         return -1;
1135 }
1136
1137 static void kcore__close(struct kcore *kcore)
1138 {
1139         elf_end(kcore->elf);
1140         close(kcore->fd);
1141 }
1142
1143 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1144 {
1145         GElf_Ehdr *ehdr = &to->ehdr;
1146         GElf_Ehdr *kehdr = &from->ehdr;
1147
1148         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1149         ehdr->e_type      = kehdr->e_type;
1150         ehdr->e_machine   = kehdr->e_machine;
1151         ehdr->e_version   = kehdr->e_version;
1152         ehdr->e_entry     = 0;
1153         ehdr->e_shoff     = 0;
1154         ehdr->e_flags     = kehdr->e_flags;
1155         ehdr->e_phnum     = count;
1156         ehdr->e_shentsize = 0;
1157         ehdr->e_shnum     = 0;
1158         ehdr->e_shstrndx  = 0;
1159
1160         if (from->elfclass == ELFCLASS32) {
1161                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1162                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1163                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1164         } else {
1165                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1166                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1167                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1168         }
1169
1170         if (!gelf_update_ehdr(to->elf, ehdr))
1171                 return -1;
1172
1173         if (!gelf_newphdr(to->elf, count))
1174                 return -1;
1175
1176         return 0;
1177 }
1178
1179 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1180                            u64 addr, u64 len)
1181 {
1182         GElf_Phdr gphdr;
1183         GElf_Phdr *phdr;
1184
1185         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1186         if (!phdr)
1187                 return -1;
1188
1189         phdr->p_type    = PT_LOAD;
1190         phdr->p_flags   = PF_R | PF_W | PF_X;
1191         phdr->p_offset  = offset;
1192         phdr->p_vaddr   = addr;
1193         phdr->p_paddr   = 0;
1194         phdr->p_filesz  = len;
1195         phdr->p_memsz   = len;
1196         phdr->p_align   = page_size;
1197
1198         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1199                 return -1;
1200
1201         return 0;
1202 }
1203
1204 static off_t kcore__write(struct kcore *kcore)
1205 {
1206         return elf_update(kcore->elf, ELF_C_WRITE);
1207 }
1208
1209 struct phdr_data {
1210         off_t offset;
1211         u64 addr;
1212         u64 len;
1213 };
1214
1215 struct kcore_copy_info {
1216         u64 stext;
1217         u64 etext;
1218         u64 first_symbol;
1219         u64 last_symbol;
1220         u64 first_module;
1221         u64 last_module_symbol;
1222         struct phdr_data kernel_map;
1223         struct phdr_data modules_map;
1224 };
1225
1226 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1227                                         u64 start)
1228 {
1229         struct kcore_copy_info *kci = arg;
1230
1231         if (!symbol_type__is_a(type, MAP__FUNCTION))
1232                 return 0;
1233
1234         if (strchr(name, '[')) {
1235                 if (start > kci->last_module_symbol)
1236                         kci->last_module_symbol = start;
1237                 return 0;
1238         }
1239
1240         if (!kci->first_symbol || start < kci->first_symbol)
1241                 kci->first_symbol = start;
1242
1243         if (!kci->last_symbol || start > kci->last_symbol)
1244                 kci->last_symbol = start;
1245
1246         if (!strcmp(name, "_stext")) {
1247                 kci->stext = start;
1248                 return 0;
1249         }
1250
1251         if (!strcmp(name, "_etext")) {
1252                 kci->etext = start;
1253                 return 0;
1254         }
1255
1256         return 0;
1257 }
1258
1259 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1260                                       const char *dir)
1261 {
1262         char kallsyms_filename[PATH_MAX];
1263
1264         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1265
1266         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1267                 return -1;
1268
1269         if (kallsyms__parse(kallsyms_filename, kci,
1270                             kcore_copy__process_kallsyms) < 0)
1271                 return -1;
1272
1273         return 0;
1274 }
1275
1276 static int kcore_copy__process_modules(void *arg,
1277                                        const char *name __maybe_unused,
1278                                        u64 start)
1279 {
1280         struct kcore_copy_info *kci = arg;
1281
1282         if (!kci->first_module || start < kci->first_module)
1283                 kci->first_module = start;
1284
1285         return 0;
1286 }
1287
1288 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1289                                      const char *dir)
1290 {
1291         char modules_filename[PATH_MAX];
1292
1293         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1294
1295         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1296                 return -1;
1297
1298         if (modules__parse(modules_filename, kci,
1299                            kcore_copy__process_modules) < 0)
1300                 return -1;
1301
1302         return 0;
1303 }
1304
1305 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1306                             u64 s, u64 e)
1307 {
1308         if (p->addr || s < start || s >= end)
1309                 return;
1310
1311         p->addr = s;
1312         p->offset = (s - start) + pgoff;
1313         p->len = e < end ? e - s : end - s;
1314 }
1315
1316 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1317 {
1318         struct kcore_copy_info *kci = data;
1319         u64 end = start + len;
1320
1321         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1322                         kci->etext);
1323
1324         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1325                         kci->last_module_symbol);
1326
1327         return 0;
1328 }
1329
1330 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1331 {
1332         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1333                 return -1;
1334
1335         return 0;
1336 }
1337
1338 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1339                                  Elf *elf)
1340 {
1341         if (kcore_copy__parse_kallsyms(kci, dir))
1342                 return -1;
1343
1344         if (kcore_copy__parse_modules(kci, dir))
1345                 return -1;
1346
1347         if (kci->stext)
1348                 kci->stext = round_down(kci->stext, page_size);
1349         else
1350                 kci->stext = round_down(kci->first_symbol, page_size);
1351
1352         if (kci->etext) {
1353                 kci->etext = round_up(kci->etext, page_size);
1354         } else if (kci->last_symbol) {
1355                 kci->etext = round_up(kci->last_symbol, page_size);
1356                 kci->etext += page_size;
1357         }
1358
1359         kci->first_module = round_down(kci->first_module, page_size);
1360
1361         if (kci->last_module_symbol) {
1362                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1363                                                    page_size);
1364                 kci->last_module_symbol += page_size;
1365         }
1366
1367         if (!kci->stext || !kci->etext)
1368                 return -1;
1369
1370         if (kci->first_module && !kci->last_module_symbol)
1371                 return -1;
1372
1373         return kcore_copy__read_maps(kci, elf);
1374 }
1375
1376 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1377                                  const char *name)
1378 {
1379         char from_filename[PATH_MAX];
1380         char to_filename[PATH_MAX];
1381
1382         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1383         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1384
1385         return copyfile_mode(from_filename, to_filename, 0400);
1386 }
1387
1388 static int kcore_copy__unlink(const char *dir, const char *name)
1389 {
1390         char filename[PATH_MAX];
1391
1392         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1393
1394         return unlink(filename);
1395 }
1396
1397 static int kcore_copy__compare_fds(int from, int to)
1398 {
1399         char *buf_from;
1400         char *buf_to;
1401         ssize_t ret;
1402         size_t len;
1403         int err = -1;
1404
1405         buf_from = malloc(page_size);
1406         buf_to = malloc(page_size);
1407         if (!buf_from || !buf_to)
1408                 goto out;
1409
1410         while (1) {
1411                 /* Use read because mmap won't work on proc files */
1412                 ret = read(from, buf_from, page_size);
1413                 if (ret < 0)
1414                         goto out;
1415
1416                 if (!ret)
1417                         break;
1418
1419                 len = ret;
1420
1421                 if (readn(to, buf_to, len) != (int)len)
1422                         goto out;
1423
1424                 if (memcmp(buf_from, buf_to, len))
1425                         goto out;
1426         }
1427
1428         err = 0;
1429 out:
1430         free(buf_to);
1431         free(buf_from);
1432         return err;
1433 }
1434
1435 static int kcore_copy__compare_files(const char *from_filename,
1436                                      const char *to_filename)
1437 {
1438         int from, to, err = -1;
1439
1440         from = open(from_filename, O_RDONLY);
1441         if (from < 0)
1442                 return -1;
1443
1444         to = open(to_filename, O_RDONLY);
1445         if (to < 0)
1446                 goto out_close_from;
1447
1448         err = kcore_copy__compare_fds(from, to);
1449
1450         close(to);
1451 out_close_from:
1452         close(from);
1453         return err;
1454 }
1455
1456 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1457                                     const char *name)
1458 {
1459         char from_filename[PATH_MAX];
1460         char to_filename[PATH_MAX];
1461
1462         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1463         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1464
1465         return kcore_copy__compare_files(from_filename, to_filename);
1466 }
1467
1468 /**
1469  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1470  * @from_dir: from directory
1471  * @to_dir: to directory
1472  *
1473  * This function copies kallsyms, modules and kcore files from one directory to
1474  * another.  kallsyms and modules are copied entirely.  Only code segments are
1475  * copied from kcore.  It is assumed that two segments suffice: one for the
1476  * kernel proper and one for all the modules.  The code segments are determined
1477  * from kallsyms and modules files.  The kernel map starts at _stext or the
1478  * lowest function symbol, and ends at _etext or the highest function symbol.
1479  * The module map starts at the lowest module address and ends at the highest
1480  * module symbol.  Start addresses are rounded down to the nearest page.  End
1481  * addresses are rounded up to the nearest page.  An extra page is added to the
1482  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1483  * symbol too.  Because it contains only code sections, the resulting kcore is
1484  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1485  * is not the same for the kernel map and the modules map.  That happens because
1486  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1487  * kallsyms and modules files are compared with their copies to check that
1488  * modules have not been loaded or unloaded while the copies were taking place.
1489  *
1490  * Return: %0 on success, %-1 on failure.
1491  */
1492 int kcore_copy(const char *from_dir, const char *to_dir)
1493 {
1494         struct kcore kcore;
1495         struct kcore extract;
1496         size_t count = 2;
1497         int idx = 0, err = -1;
1498         off_t offset = page_size, sz, modules_offset = 0;
1499         struct kcore_copy_info kci = { .stext = 0, };
1500         char kcore_filename[PATH_MAX];
1501         char extract_filename[PATH_MAX];
1502
1503         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1504                 return -1;
1505
1506         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1507                 goto out_unlink_kallsyms;
1508
1509         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1510         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1511
1512         if (kcore__open(&kcore, kcore_filename))
1513                 goto out_unlink_modules;
1514
1515         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1516                 goto out_kcore_close;
1517
1518         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1519                 goto out_kcore_close;
1520
1521         if (!kci.modules_map.addr)
1522                 count -= 1;
1523
1524         if (kcore__copy_hdr(&kcore, &extract, count))
1525                 goto out_extract_close;
1526
1527         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1528                             kci.kernel_map.len))
1529                 goto out_extract_close;
1530
1531         if (kci.modules_map.addr) {
1532                 modules_offset = offset + kci.kernel_map.len;
1533                 if (kcore__add_phdr(&extract, idx, modules_offset,
1534                                     kci.modules_map.addr, kci.modules_map.len))
1535                         goto out_extract_close;
1536         }
1537
1538         sz = kcore__write(&extract);
1539         if (sz < 0 || sz > offset)
1540                 goto out_extract_close;
1541
1542         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1543                        kci.kernel_map.len))
1544                 goto out_extract_close;
1545
1546         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1547                                          extract.fd, modules_offset,
1548                                          kci.modules_map.len))
1549                 goto out_extract_close;
1550
1551         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1552                 goto out_extract_close;
1553
1554         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1555                 goto out_extract_close;
1556
1557         err = 0;
1558
1559 out_extract_close:
1560         kcore__close(&extract);
1561         if (err)
1562                 unlink(extract_filename);
1563 out_kcore_close:
1564         kcore__close(&kcore);
1565 out_unlink_modules:
1566         if (err)
1567                 kcore_copy__unlink(to_dir, "modules");
1568 out_unlink_kallsyms:
1569         if (err)
1570                 kcore_copy__unlink(to_dir, "kallsyms");
1571
1572         return err;
1573 }
1574
1575 int kcore_extract__create(struct kcore_extract *kce)
1576 {
1577         struct kcore kcore;
1578         struct kcore extract;
1579         size_t count = 1;
1580         int idx = 0, err = -1;
1581         off_t offset = page_size, sz;
1582
1583         if (kcore__open(&kcore, kce->kcore_filename))
1584                 return -1;
1585
1586         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1587         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1588                 goto out_kcore_close;
1589
1590         if (kcore__copy_hdr(&kcore, &extract, count))
1591                 goto out_extract_close;
1592
1593         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1594                 goto out_extract_close;
1595
1596         sz = kcore__write(&extract);
1597         if (sz < 0 || sz > offset)
1598                 goto out_extract_close;
1599
1600         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1601                 goto out_extract_close;
1602
1603         err = 0;
1604
1605 out_extract_close:
1606         kcore__close(&extract);
1607         if (err)
1608                 unlink(kce->extract_filename);
1609 out_kcore_close:
1610         kcore__close(&kcore);
1611
1612         return err;
1613 }
1614
1615 void kcore_extract__delete(struct kcore_extract *kce)
1616 {
1617         unlink(kce->extract_filename);
1618 }
1619
1620 void symbol__elf_init(void)
1621 {
1622         elf_version(EV_CURRENT);
1623 }