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 "vdso.h"
  10 #include <symbol/kallsyms.h>
  11 #include "debug.h"
  12
  13 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  14 static int elf_getphdrnum(Elf *elf, size_t *dst)
  15 {
  16         GElf_Ehdr gehdr;
  17         GElf_Ehdr *ehdr;
  18
  19         ehdr = gelf_getehdr(elf, &gehdr);
  20         if (!ehdr)
  21                 return -1;
  22
  23         *dst = ehdr->e_phnum;
  24
  25         return 0;
  26 }
  27 #endif
  28
  29 #ifndef NT_GNU_BUILD_ID
  30 #define NT_GNU_BUILD_ID 3
  31 #endif
  32
  33 /**
  34  * elf_symtab__for_each_symbol - iterate thru all the symbols
  35  *
  36  * @syms: struct elf_symtab instance to iterate
  37  * @idx: uint32_t idx
  38  * @sym: GElf_Sym iterator
  39  */
  40 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  41         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  42              idx < nr_syms; \
  43              idx++, gelf_getsym(syms, idx, &sym))
  44
  45 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  46 {
  47         return GELF_ST_TYPE(sym->st_info);
  48 }
  49
  50 static inline int elf_sym__is_function(const GElf_Sym *sym)
  51 {
  52         return (elf_sym__type(sym) == STT_FUNC ||
  53                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  54                sym->st_name != 0 &&
  55                sym->st_shndx != SHN_UNDEF;
  56 }
  57
  58 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  59 {
  60         return elf_sym__type(sym) == STT_OBJECT &&
  61                 sym->st_name != 0 &&
  62                 sym->st_shndx != SHN_UNDEF;
  63 }
  64
  65 static inline int elf_sym__is_label(const GElf_Sym *sym)
  66 {
  67         return elf_sym__type(sym) == STT_NOTYPE &&
  68                 sym->st_name != 0 &&
  69                 sym->st_shndx != SHN_UNDEF &&
  70                 sym->st_shndx != SHN_ABS;
  71 }
  72
  73 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
  74 {
  75         switch (type) {
  76         case MAP__FUNCTION:
  77                 return elf_sym__is_function(sym);
  78         case MAP__VARIABLE:
  79                 return elf_sym__is_object(sym);
  80         default:
  81                 return false;
  82         }
  83 }
  84
  85 static inline const char *elf_sym__name(const GElf_Sym *sym,
  86                                         const Elf_Data *symstrs)
  87 {
  88         return symstrs->d_buf + sym->st_name;
  89 }
  90
  91 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  92                                         const Elf_Data *secstrs)
  93 {
  94         return secstrs->d_buf + shdr->sh_name;
  95 }
  96
  97 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  98                                         const Elf_Data *secstrs)
  99 {
 100         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 101 }
 102
 103 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 104                                     const Elf_Data *secstrs)
 105 {
 106         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 107 }
 108
 109 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 110                           enum map_type type)
 111 {
 112         switch (type) {
 113         case MAP__FUNCTION:
 114                 return elf_sec__is_text(shdr, secstrs);
 115         case MAP__VARIABLE:
 116                 return elf_sec__is_data(shdr, secstrs);
 117         default:
 118                 return false;
 119         }
 120 }
 121
 122 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 123 {
 124         Elf_Scn *sec = NULL;
 125         GElf_Shdr shdr;
 126         size_t cnt = 1;
 127
 128         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 129                 gelf_getshdr(sec, &shdr);
 130
 131                 if ((addr >= shdr.sh_addr) &&
 132                     (addr < (shdr.sh_addr + shdr.sh_size)))
 133                         return cnt;
 134
 135                 ++cnt;
 136         }
 137
 138         return -1;
 139 }
 140
 141 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 142                              GElf_Shdr *shp, const char *name, size_t *idx)
 143 {
 144         Elf_Scn *sec = NULL;
 145         size_t cnt = 1;
 146
 147         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 148         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 149                 return NULL;
 150
 151         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 152                 char *str;
 153
 154                 gelf_getshdr(sec, shp);
 155                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 156                 if (str && !strcmp(name, str)) {
 157                         if (idx)
 158                                 *idx = cnt;
 159                         return sec;
 160                 }
 161                 ++cnt;
 162         }
 163
 164         return NULL;
 165 }
 166
 167 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 168         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 169              idx < nr_entries; \
 170              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 171
 172 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 173         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 174              idx < nr_entries; \
 175              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 176
 177 /*
 178  * We need to check if we have a .dynsym, so that we can handle the
 179  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 180  * .dynsym or .symtab).
 181  * And always look at the original dso, not at debuginfo packages, that
 182  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 183  */
 184 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 185                                 symbol_filter_t filter)
 186 {
 187         uint32_t nr_rel_entries, idx;
 188         GElf_Sym sym;
 189         u64 plt_offset;
 190         GElf_Shdr shdr_plt;
 191         struct symbol *f;
 192         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 193         Elf_Data *reldata, *syms, *symstrs;
 194         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 195         size_t dynsym_idx;
 196         GElf_Ehdr ehdr;
 197         char sympltname[1024];
 198         Elf *elf;
 199         int nr = 0, symidx, err = 0;
 200
 201         if (!ss->dynsym)
 202                 return 0;
 203
 204         elf = ss->elf;
 205         ehdr = ss->ehdr;
 206
 207         scn_dynsym = ss->dynsym;
 208         shdr_dynsym = ss->dynshdr;
 209         dynsym_idx = ss->dynsym_idx;
 210
 211         if (scn_dynsym == NULL)
 212                 goto out_elf_end;
 213
 214         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 215                                           ".rela.plt", NULL);
 216         if (scn_plt_rel == NULL) {
 217                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 218                                                   ".rel.plt", NULL);
 219                 if (scn_plt_rel == NULL)
 220                         goto out_elf_end;
 221         }
 222
 223         err = -1;
 224
 225         if (shdr_rel_plt.sh_link != dynsym_idx)
 226                 goto out_elf_end;
 227
 228         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 229                 goto out_elf_end;
 230
 231         /*
 232          * Fetch the relocation section to find the idxes to the GOT
 233          * and the symbols in the .dynsym they refer to.
 234          */
 235         reldata = elf_getdata(scn_plt_rel, NULL);
 236         if (reldata == NULL)
 237                 goto out_elf_end;
 238
 239         syms = elf_getdata(scn_dynsym, NULL);
 240         if (syms == NULL)
 241                 goto out_elf_end;
 242
 243         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 244         if (scn_symstrs == NULL)
 245                 goto out_elf_end;
 246
 247         symstrs = elf_getdata(scn_symstrs, NULL);
 248         if (symstrs == NULL)
 249                 goto out_elf_end;
 250
 251         if (symstrs->d_size == 0)
 252                 goto out_elf_end;
 253
 254         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 255         plt_offset = shdr_plt.sh_offset;
 256
 257         if (shdr_rel_plt.sh_type == SHT_RELA) {
 258                 GElf_Rela pos_mem, *pos;
 259
 260                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 261                                            nr_rel_entries) {
 262                         symidx = GELF_R_SYM(pos->r_info);
 263                         plt_offset += shdr_plt.sh_entsize;
 264                         gelf_getsym(syms, symidx, &sym);
 265                         snprintf(sympltname, sizeof(sympltname),
 266                                  "%s@plt", elf_sym__name(&sym, symstrs));
 267
 268                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 269                                         STB_GLOBAL, sympltname);
 270                         if (!f)
 271                                 goto out_elf_end;
 272
 273                         if (filter && filter(map, f))
 274                                 symbol__delete(f);
 275                         else {
 276                                 symbols__insert(&dso->symbols[map->type], f);
 277                                 ++nr;
 278                         }
 279                 }
 280         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 281                 GElf_Rel pos_mem, *pos;
 282                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 283                                           nr_rel_entries) {
 284                         symidx = GELF_R_SYM(pos->r_info);
 285                         plt_offset += shdr_plt.sh_entsize;
 286                         gelf_getsym(syms, symidx, &sym);
 287                         snprintf(sympltname, sizeof(sympltname),
 288                                  "%s@plt", elf_sym__name(&sym, symstrs));
 289
 290                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 291                                         STB_GLOBAL, sympltname);
 292                         if (!f)
 293                                 goto out_elf_end;
 294
 295                         if (filter && filter(map, f))
 296                                 symbol__delete(f);
 297                         else {
 298                                 symbols__insert(&dso->symbols[map->type], f);
 299                                 ++nr;
 300                         }
 301                 }
 302         }
 303
 304         err = 0;
 305 out_elf_end:
 306         if (err == 0)
 307                 return nr;
 308         pr_debug("%s: problems reading %s PLT info.\n",
 309                  __func__, dso->long_name);
 310         return 0;
 311 }
 312
 313 /*
 314  * Align offset to 4 bytes as needed for note name and descriptor data.
 315  */
 316 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 317
 318 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 319 {
 320         int err = -1;
 321         GElf_Ehdr ehdr;
 322         GElf_Shdr shdr;
 323         Elf_Data *data;
 324         Elf_Scn *sec;
 325         Elf_Kind ek;
 326         void *ptr;
 327
 328         if (size < BUILD_ID_SIZE)
 329                 goto out;
 330
 331         ek = elf_kind(elf);
 332         if (ek != ELF_K_ELF)
 333                 goto out;
 334
 335         if (gelf_getehdr(elf, &ehdr) == NULL) {
 336                 pr_err("%s: cannot get elf header.\n", __func__);
 337                 goto out;
 338         }
 339
 340         /*
 341          * Check following sections for notes:
 342          *   '.note.gnu.build-id'
 343          *   '.notes'
 344          *   '.note' (VDSO specific)
 345          */
 346         do {
 347                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 348                                           ".note.gnu.build-id", NULL);
 349                 if (sec)
 350                         break;
 351
 352                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 353                                           ".notes", NULL);
 354                 if (sec)
 355                         break;
 356
 357                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 358                                           ".note", NULL);
 359                 if (sec)
 360                         break;
 361
 362                 return err;
 363
 364         } while (0);
 365
 366         data = elf_getdata(sec, NULL);
 367         if (data == NULL)
 368                 goto out;
 369
 370         ptr = data->d_buf;
 371         while (ptr < (data->d_buf + data->d_size)) {
 372                 GElf_Nhdr *nhdr = ptr;
 373                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 374                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 375                 const char *name;
 376
 377                 ptr += sizeof(*nhdr);
 378                 name = ptr;
 379                 ptr += namesz;
 380                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 381                     nhdr->n_namesz == sizeof("GNU")) {
 382                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 383                                 size_t sz = min(size, descsz);
 384                                 memcpy(bf, ptr, sz);
 385                                 memset(bf + sz, 0, size - sz);
 386                                 err = descsz;
 387                                 break;
 388                         }
 389                 }
 390                 ptr += descsz;
 391         }
 392
 393 out:
 394         return err;
 395 }
 396
 397 int filename__read_build_id(const char *filename, void *bf, size_t size)
 398 {
 399         int fd, err = -1;
 400         Elf *elf;
 401
 402         if (size < BUILD_ID_SIZE)
 403                 goto out;
 404
 405         fd = open(filename, O_RDONLY);
 406         if (fd < 0)
 407                 goto out;
 408
 409         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 410         if (elf == NULL) {
 411                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 412                 goto out_close;
 413         }
 414
 415         err = elf_read_build_id(elf, bf, size);
 416
 417         elf_end(elf);
 418 out_close:
 419         close(fd);
 420 out:
 421         return err;
 422 }
 423
 424 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 425 {
 426         int fd, err = -1;
 427
 428         if (size < BUILD_ID_SIZE)
 429                 goto out;
 430
 431         fd = open(filename, O_RDONLY);
 432         if (fd < 0)
 433                 goto out;
 434
 435         while (1) {
 436                 char bf[BUFSIZ];
 437                 GElf_Nhdr nhdr;
 438                 size_t namesz, descsz;
 439
 440                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 441                         break;
 442
 443                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 444                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 445                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 446                     nhdr.n_namesz == sizeof("GNU")) {
 447                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 448                                 break;
 449                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 450                                 size_t sz = min(descsz, size);
 451                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 452                                         memset(build_id + sz, 0, size - sz);
 453                                         err = 0;
 454                                         break;
 455                                 }
 456                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 457                                 break;
 458                 } else {
 459                         int n = namesz + descsz;
 460                         if (read(fd, bf, n) != n)
 461                                 break;
 462                 }
 463         }
 464         close(fd);
 465 out:
 466         return err;
 467 }
 468
 469 int filename__read_debuglink(const char *filename, char *debuglink,
 470                              size_t size)
 471 {
 472         int fd, err = -1;
 473         Elf *elf;
 474         GElf_Ehdr ehdr;
 475         GElf_Shdr shdr;
 476         Elf_Data *data;
 477         Elf_Scn *sec;
 478         Elf_Kind ek;
 479
 480         fd = open(filename, O_RDONLY);
 481         if (fd < 0)
 482                 goto out;
 483
 484         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 485         if (elf == NULL) {
 486                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 487                 goto out_close;
 488         }
 489
 490         ek = elf_kind(elf);
 491         if (ek != ELF_K_ELF)
 492                 goto out_elf_end;
 493
 494         if (gelf_getehdr(elf, &ehdr) == NULL) {
 495                 pr_err("%s: cannot get elf header.\n", __func__);
 496                 goto out_elf_end;
 497         }
 498
 499         sec = elf_section_by_name(elf, &ehdr, &shdr,
 500                                   ".gnu_debuglink", NULL);
 501         if (sec == NULL)
 502                 goto out_elf_end;
 503
 504         data = elf_getdata(sec, NULL);
 505         if (data == NULL)
 506                 goto out_elf_end;
 507
 508         /* the start of this section is a zero-terminated string */
 509         strncpy(debuglink, data->d_buf, size);
 510
 511         err = 0;
 512
 513 out_elf_end:
 514         elf_end(elf);
 515 out_close:
 516         close(fd);
 517 out:
 518         return err;
 519 }
 520
 521 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 522 {
 523         static unsigned int const endian = 1;
 524
 525         dso->needs_swap = DSO_SWAP__NO;
 526
 527         switch (eidata) {
 528         case ELFDATA2LSB:
 529                 /* We are big endian, DSO is little endian. */
 530                 if (*(unsigned char const *)&endian != 1)
 531                         dso->needs_swap = DSO_SWAP__YES;
 532                 break;
 533
 534         case ELFDATA2MSB:
 535                 /* We are little endian, DSO is big endian. */
 536                 if (*(unsigned char const *)&endian != 0)
 537                         dso->needs_swap = DSO_SWAP__YES;
 538                 break;
 539
 540         default:
 541                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 542                 return -EINVAL;
 543         }
 544
 545         return 0;
 546 }
 547
 548 bool symsrc__possibly_runtime(struct symsrc *ss)
 549 {
 550         return ss->dynsym || ss->opdsec;
 551 }
 552
 553 bool symsrc__has_symtab(struct symsrc *ss)
 554 {
 555         return ss->symtab != NULL;
 556 }
 557
 558 void symsrc__destroy(struct symsrc *ss)
 559 {
 560         zfree(&ss->name);
 561         elf_end(ss->elf);
 562         close(ss->fd);
 563 }
 564
 565 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 566                  enum dso_binary_type type)
 567 {
 568         int err = -1;
 569         GElf_Ehdr ehdr;
 570         Elf *elf;
 571         int fd;
 572
 573         fd = open(name, O_RDONLY);
 574         if (fd < 0)
 575                 return -1;
 576
 577         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 578         if (elf == NULL) {
 579                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 580                 goto out_close;
 581         }
 582
 583         if (gelf_getehdr(elf, &ehdr) == NULL) {
 584                 pr_debug("%s: cannot get elf header.\n", __func__);
 585                 goto out_elf_end;
 586         }
 587
 588         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 589                 goto out_elf_end;
 590
 591         /* Always reject images with a mismatched build-id: */
 592         if (dso->has_build_id) {
 593                 u8 build_id[BUILD_ID_SIZE];
 594
 595                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 596                         goto out_elf_end;
 597
 598                 if (!dso__build_id_equal(dso, build_id))
 599                         goto out_elf_end;
 600         }
 601
 602         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 603
 604         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 605                         NULL);
 606         if (ss->symshdr.sh_type != SHT_SYMTAB)
 607                 ss->symtab = NULL;
 608
 609         ss->dynsym_idx = 0;
 610         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 611                         &ss->dynsym_idx);
 612         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 613                 ss->dynsym = NULL;
 614
 615         ss->opdidx = 0;
 616         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 617                         &ss->opdidx);
 618         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 619                 ss->opdsec = NULL;
 620
 621         if (dso->kernel == DSO_TYPE_USER) {
 622                 GElf_Shdr shdr;
 623                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 624                                 ehdr.e_type == ET_REL ||
 625                                 dso__is_vdso(dso) ||
 626                                 elf_section_by_name(elf, &ehdr, &shdr,
 627                                                      ".gnu.prelink_undo",
 628                                                      NULL) != NULL);
 629         } else {
 630                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 631                                      ehdr.e_type == ET_REL;
 632         }
 633
 634         ss->name   = strdup(name);
 635         if (!ss->name)
 636                 goto out_elf_end;
 637
 638         ss->elf    = elf;
 639         ss->fd     = fd;
 640         ss->ehdr   = ehdr;
 641         ss->type   = type;
 642
 643         return 0;
 644
 645 out_elf_end:
 646         elf_end(elf);
 647 out_close:
 648         close(fd);
 649         return err;
 650 }
 651
 652 /**
 653  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 654  * @kmap: kernel maps and relocation reference symbol
 655  *
 656  * This function returns %true if we are dealing with the kernel maps and the
 657  * relocation reference symbol has not yet been found.  Otherwise %false is
 658  * returned.
 659  */
 660 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 661 {
 662         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 663                !kmap->ref_reloc_sym->unrelocated_addr;
 664 }
 665
 666 /**
 667  * ref_reloc - kernel relocation offset.
 668  * @kmap: kernel maps and relocation reference symbol
 669  *
 670  * This function returns the offset of kernel addresses as determined by using
 671  * the relocation reference symbol i.e. if the kernel has not been relocated
 672  * then the return value is zero.
 673  */
 674 static u64 ref_reloc(struct kmap *kmap)
 675 {
 676         if (kmap && kmap->ref_reloc_sym &&
 677             kmap->ref_reloc_sym->unrelocated_addr)
 678                 return kmap->ref_reloc_sym->addr -
 679                        kmap->ref_reloc_sym->unrelocated_addr;
 680         return 0;
 681 }
 682
 683 int dso__load_sym(struct dso *dso, struct map *map,
 684                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 685                   symbol_filter_t filter, int kmodule)
 686 {
 687         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 688         struct map *curr_map = map;
 689         struct dso *curr_dso = dso;
 690         Elf_Data *symstrs, *secstrs;
 691         uint32_t nr_syms;
 692         int err = -1;
 693         uint32_t idx;
 694         GElf_Ehdr ehdr;
 695         GElf_Shdr shdr;
 696         Elf_Data *syms, *opddata = NULL;
 697         GElf_Sym sym;
 698         Elf_Scn *sec, *sec_strndx;
 699         Elf *elf;
 700         int nr = 0;
 701         bool remap_kernel = false, adjust_kernel_syms = false;
 702
 703         dso->symtab_type = syms_ss->type;
 704         dso->is_64_bit = syms_ss->is_64_bit;
 705         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 706
 707         /*
 708          * Modules may already have symbols from kallsyms, but those symbols
 709          * have the wrong values for the dso maps, so remove them.
 710          */
 711         if (kmodule && syms_ss->symtab)
 712                 symbols__delete(&dso->symbols[map->type]);
 713
 714         if (!syms_ss->symtab) {
 715                 syms_ss->symtab  = syms_ss->dynsym;
 716                 syms_ss->symshdr = syms_ss->dynshdr;
 717         }
 718
 719         elf = syms_ss->elf;
 720         ehdr = syms_ss->ehdr;
 721         sec = syms_ss->symtab;
 722         shdr = syms_ss->symshdr;
 723
 724         if (runtime_ss->opdsec)
 725                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 726
 727         syms = elf_getdata(sec, NULL);
 728         if (syms == NULL)
 729                 goto out_elf_end;
 730
 731         sec = elf_getscn(elf, shdr.sh_link);
 732         if (sec == NULL)
 733                 goto out_elf_end;
 734
 735         symstrs = elf_getdata(sec, NULL);
 736         if (symstrs == NULL)
 737                 goto out_elf_end;
 738
 739         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 740         if (sec_strndx == NULL)
 741                 goto out_elf_end;
 742
 743         secstrs = elf_getdata(sec_strndx, NULL);
 744         if (secstrs == NULL)
 745                 goto out_elf_end;
 746
 747         nr_syms = shdr.sh_size / shdr.sh_entsize;
 748
 749         memset(&sym, 0, sizeof(sym));
 750
 751         /*
 752          * The kernel relocation symbol is needed in advance in order to adjust
 753          * kernel maps correctly.
 754          */
 755         if (ref_reloc_sym_not_found(kmap)) {
 756                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 757                         const char *elf_name = elf_sym__name(&sym, symstrs);
 758
 759                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 760                                 continue;
 761                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 762                         map->reloc = kmap->ref_reloc_sym->addr -
 763                                      kmap->ref_reloc_sym->unrelocated_addr;
 764                         break;
 765                 }
 766         }
 767
 768         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 769         /*
 770          * Initial kernel and module mappings do not map to the dso.  For
 771          * function mappings, flag the fixups.
 772          */
 773         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 774                 remap_kernel = true;
 775                 adjust_kernel_syms = dso->adjust_symbols;
 776         }
 777         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 778                 struct symbol *f;
 779                 const char *elf_name = elf_sym__name(&sym, symstrs);
 780                 char *demangled = NULL;
 781                 int is_label = elf_sym__is_label(&sym);
 782                 const char *section_name;
 783                 bool used_opd = false;
 784
 785                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 786                         continue;
 787
 788                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 789                  * don't identify functions, so will confuse the profile
 790                  * output: */
 791                 if (ehdr.e_machine == EM_ARM) {
 792                         if (!strcmp(elf_name, "$a") ||
 793                             !strcmp(elf_name, "$d") ||
 794                             !strcmp(elf_name, "$t"))
 795                                 continue;
 796                 }
 797
 798                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 799                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 800                         u64 *opd = opddata->d_buf + offset;
 801                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 802                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 803                                         sym.st_value);
 804                         used_opd = true;
 805                 }
 806                 /*
 807                  * When loading symbols in a data mapping, ABS symbols (which
 808                  * has a value of SHN_ABS in its st_shndx) failed at
 809                  * elf_getscn().  And it marks the loading as a failure so
 810                  * already loaded symbols cannot be fixed up.
 811                  *
 812                  * I'm not sure what should be done. Just ignore them for now.
 813                  * - Namhyung Kim
 814                  */
 815                 if (sym.st_shndx == SHN_ABS)
 816                         continue;
 817
 818                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 819                 if (!sec)
 820                         goto out_elf_end;
 821
 822                 gelf_getshdr(sec, &shdr);
 823
 824                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 825                         continue;
 826
 827                 section_name = elf_sec__name(&shdr, secstrs);
 828
 829                 /* On ARM, symbols for thumb functions have 1 added to
 830                  * the symbol address as a flag - remove it */
 831                 if ((ehdr.e_machine == EM_ARM) &&
 832                     (map->type == MAP__FUNCTION) &&
 833                     (sym.st_value & 1))
 834                         --sym.st_value;
 835
 836                 if (dso->kernel || kmodule) {
 837                         char dso_name[PATH_MAX];
 838
 839                         /* Adjust symbol to map to file offset */
 840                         if (adjust_kernel_syms)
 841                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 842
 843                         if (strcmp(section_name,
 844                                    (curr_dso->short_name +
 845                                     dso->short_name_len)) == 0)
 846                                 goto new_symbol;
 847
 848                         if (strcmp(section_name, ".text") == 0) {
 849                                 /*
 850                                  * The initial kernel mapping is based on
 851                                  * kallsyms and identity maps.  Overwrite it to
 852                                  * map to the kernel dso.
 853                                  */
 854                                 if (remap_kernel && dso->kernel) {
 855                                         remap_kernel = false;
 856                                         map->start = shdr.sh_addr +
 857                                                      ref_reloc(kmap);
 858                                         map->end = map->start + shdr.sh_size;
 859                                         map->pgoff = shdr.sh_offset;
 860                                         map->map_ip = map__map_ip;
 861                                         map->unmap_ip = map__unmap_ip;
 862                                         /* Ensure maps are correctly ordered */
 863                                         map_groups__remove(kmap->kmaps, map);
 864                                         map_groups__insert(kmap->kmaps, map);
 865                                 }
 866
 867                                 /*
 868                                  * The initial module mapping is based on
 869                                  * /proc/modules mapped to offset zero.
 870                                  * Overwrite it to map to the module dso.
 871                                  */
 872                                 if (remap_kernel && kmodule) {
 873                                         remap_kernel = false;
 874                                         map->pgoff = shdr.sh_offset;
 875                                 }
 876
 877                                 curr_map = map;
 878                                 curr_dso = dso;
 879                                 goto new_symbol;
 880                         }
 881
 882                         if (!kmap)
 883                                 goto new_symbol;
 884
 885                         snprintf(dso_name, sizeof(dso_name),
 886                                  "%s%s", dso->short_name, section_name);
 887
 888                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 889                         if (curr_map == NULL) {
 890                                 u64 start = sym.st_value;
 891
 892                                 if (kmodule)
 893                                         start += map->start + shdr.sh_offset;
 894
 895                                 curr_dso = dso__new(dso_name);
 896                                 if (curr_dso == NULL)
 897                                         goto out_elf_end;
 898                                 curr_dso->kernel = dso->kernel;
 899                                 curr_dso->long_name = dso->long_name;
 900                                 curr_dso->long_name_len = dso->long_name_len;
 901                                 curr_map = map__new2(start, curr_dso,
 902                                                      map->type);
 903                                 if (curr_map == NULL) {
 904                                         dso__delete(curr_dso);
 905                                         goto out_elf_end;
 906                                 }
 907                                 if (adjust_kernel_syms) {
 908                                         curr_map->start = shdr.sh_addr +
 909                                                           ref_reloc(kmap);
 910                                         curr_map->end = curr_map->start +
 911                                                         shdr.sh_size;
 912                                         curr_map->pgoff = shdr.sh_offset;
 913                                 } else {
 914                                         curr_map->map_ip = identity__map_ip;
 915                                         curr_map->unmap_ip = identity__map_ip;
 916                                 }
 917                                 curr_dso->symtab_type = dso->symtab_type;
 918                                 map_groups__insert(kmap->kmaps, curr_map);
 919                                 dsos__add(&dso->node, curr_dso);
 920                                 dso__set_loaded(curr_dso, map->type);
 921                         } else
 922                                 curr_dso = curr_map->dso;
 923
 924                         goto new_symbol;
 925                 }
 926
 927                 if ((used_opd && runtime_ss->adjust_symbols)
 928                                 || (!used_opd && syms_ss->adjust_symbols)) {
 929                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 930                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 931                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 932                                   (u64)shdr.sh_offset);
 933                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 934                 }
 935 new_symbol:
 936                 /*
 937                  * We need to figure out if the object was created from C++ sources
 938                  * DWARF DW_compile_unit has this, but we don't always have access
 939                  * to it...
 940                  */
 941                 if (symbol_conf.demangle) {
 942                         demangled = bfd_demangle(NULL, elf_name,
 943                                                  DMGL_PARAMS | DMGL_ANSI);
 944                         if (demangled != NULL)
 945                                 elf_name = demangled;
 946                 }
 947                 f = symbol__new(sym.st_value, sym.st_size,
 948                                 GELF_ST_BIND(sym.st_info), elf_name);
 949                 free(demangled);
 950                 if (!f)
 951                         goto out_elf_end;
 952
 953                 if (filter && filter(curr_map, f))
 954                         symbol__delete(f);
 955                 else {
 956                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
 957                         nr++;
 958                 }
 959         }
 960
 961         /*
 962          * For misannotated, zeroed, ASM function sizes.
 963          */
 964         if (nr > 0) {
 965                 symbols__fixup_duplicate(&dso->symbols[map->type]);
 966                 symbols__fixup_end(&dso->symbols[map->type]);
 967                 if (kmap) {
 968                         /*
 969                          * We need to fixup this here too because we create new
 970                          * maps here, for things like vsyscall sections.
 971                          */
 972                         __map_groups__fixup_end(kmap->kmaps, map->type);
 973                 }
 974         }
 975         err = nr;
 976 out_elf_end:
 977         return err;
 978 }
 979
 980 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
 981 {
 982         GElf_Phdr phdr;
 983         size_t i, phdrnum;
 984         int err;
 985         u64 sz;
 986
 987         if (elf_getphdrnum(elf, &phdrnum))
 988                 return -1;
 989
 990         for (i = 0; i < phdrnum; i++) {
 991                 if (gelf_getphdr(elf, i, &phdr) == NULL)
 992                         return -1;
 993                 if (phdr.p_type != PT_LOAD)
 994                         continue;
 995                 if (exe) {
 996                         if (!(phdr.p_flags & PF_X))
 997                                 continue;
 998                 } else {
 999                         if (!(phdr.p_flags & PF_R))
1000                                 continue;
1001                 }
1002                 sz = min(phdr.p_memsz, phdr.p_filesz);
1003                 if (!sz)
1004                         continue;
1005                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1006                 if (err)
1007                         return err;
1008         }
1009         return 0;
1010 }
1011
1012 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1013                     bool *is_64_bit)
1014 {
1015         int err;
1016         Elf *elf;
1017
1018         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1019         if (elf == NULL)
1020                 return -1;
1021
1022         if (is_64_bit)
1023                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1024
1025         err = elf_read_maps(elf, exe, mapfn, data);
1026
1027         elf_end(elf);
1028         return err;
1029 }
1030
1031 enum dso_type dso__type_fd(int fd)
1032 {
1033         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1034         GElf_Ehdr ehdr;
1035         Elf_Kind ek;
1036         Elf *elf;
1037
1038         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1039         if (elf == NULL)
1040                 goto out;
1041
1042         ek = elf_kind(elf);
1043         if (ek != ELF_K_ELF)
1044                 goto out_end;
1045
1046         if (gelf_getclass(elf) == ELFCLASS64) {
1047                 dso_type = DSO__TYPE_64BIT;
1048                 goto out_end;
1049         }
1050
1051         if (gelf_getehdr(elf, &ehdr) == NULL)
1052                 goto out_end;
1053
1054         if (ehdr.e_machine == EM_X86_64)
1055                 dso_type = DSO__TYPE_X32BIT;
1056         else
1057                 dso_type = DSO__TYPE_32BIT;
1058 out_end:
1059         elf_end(elf);
1060 out:
1061         return dso_type;
1062 }
1063
1064 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1065 {
1066         ssize_t r;
1067         size_t n;
1068         int err = -1;
1069         char *buf = malloc(page_size);
1070
1071         if (buf == NULL)
1072                 return -1;
1073
1074         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1075                 goto out;
1076
1077         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1078                 goto out;
1079
1080         while (len) {
1081                 n = page_size;
1082                 if (len < n)
1083                         n = len;
1084                 /* Use read because mmap won't work on proc files */
1085                 r = read(from, buf, n);
1086                 if (r < 0)
1087                         goto out;
1088                 if (!r)
1089                         break;
1090                 n = r;
1091                 r = write(to, buf, n);
1092                 if (r < 0)
1093                         goto out;
1094                 if ((size_t)r != n)
1095                         goto out;
1096                 len -= n;
1097         }
1098
1099         err = 0;
1100 out:
1101         free(buf);
1102         return err;
1103 }
1104
1105 struct kcore {
1106         int fd;
1107         int elfclass;
1108         Elf *elf;
1109         GElf_Ehdr ehdr;
1110 };
1111
1112 static int kcore__open(struct kcore *kcore, const char *filename)
1113 {
1114         GElf_Ehdr *ehdr;
1115
1116         kcore->fd = open(filename, O_RDONLY);
1117         if (kcore->fd == -1)
1118                 return -1;
1119
1120         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1121         if (!kcore->elf)
1122                 goto out_close;
1123
1124         kcore->elfclass = gelf_getclass(kcore->elf);
1125         if (kcore->elfclass == ELFCLASSNONE)
1126                 goto out_end;
1127
1128         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1129         if (!ehdr)
1130                 goto out_end;
1131
1132         return 0;
1133
1134 out_end:
1135         elf_end(kcore->elf);
1136 out_close:
1137         close(kcore->fd);
1138         return -1;
1139 }
1140
1141 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1142                        bool temp)
1143 {
1144         GElf_Ehdr *ehdr;
1145
1146         kcore->elfclass = elfclass;
1147
1148         if (temp)
1149                 kcore->fd = mkstemp(filename);
1150         else
1151                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1152         if (kcore->fd == -1)
1153                 return -1;
1154
1155         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1156         if (!kcore->elf)
1157                 goto out_close;
1158
1159         if (!gelf_newehdr(kcore->elf, elfclass))
1160                 goto out_end;
1161
1162         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1163         if (!ehdr)
1164                 goto out_end;
1165
1166         return 0;
1167
1168 out_end:
1169         elf_end(kcore->elf);
1170 out_close:
1171         close(kcore->fd);
1172         unlink(filename);
1173         return -1;
1174 }
1175
1176 static void kcore__close(struct kcore *kcore)
1177 {
1178         elf_end(kcore->elf);
1179         close(kcore->fd);
1180 }
1181
1182 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1183 {
1184         GElf_Ehdr *ehdr = &to->ehdr;
1185         GElf_Ehdr *kehdr = &from->ehdr;
1186
1187         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1188         ehdr->e_type      = kehdr->e_type;
1189         ehdr->e_machine   = kehdr->e_machine;
1190         ehdr->e_version   = kehdr->e_version;
1191         ehdr->e_entry     = 0;
1192         ehdr->e_shoff     = 0;
1193         ehdr->e_flags     = kehdr->e_flags;
1194         ehdr->e_phnum     = count;
1195         ehdr->e_shentsize = 0;
1196         ehdr->e_shnum     = 0;
1197         ehdr->e_shstrndx  = 0;
1198
1199         if (from->elfclass == ELFCLASS32) {
1200                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1201                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1202                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1203         } else {
1204                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1205                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1206                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1207         }
1208
1209         if (!gelf_update_ehdr(to->elf, ehdr))
1210                 return -1;
1211
1212         if (!gelf_newphdr(to->elf, count))
1213                 return -1;
1214
1215         return 0;
1216 }
1217
1218 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1219                            u64 addr, u64 len)
1220 {
1221         GElf_Phdr gphdr;
1222         GElf_Phdr *phdr;
1223
1224         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1225         if (!phdr)
1226                 return -1;
1227
1228         phdr->p_type    = PT_LOAD;
1229         phdr->p_flags   = PF_R | PF_W | PF_X;
1230         phdr->p_offset  = offset;
1231         phdr->p_vaddr   = addr;
1232         phdr->p_paddr   = 0;
1233         phdr->p_filesz  = len;
1234         phdr->p_memsz   = len;
1235         phdr->p_align   = page_size;
1236
1237         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1238                 return -1;
1239
1240         return 0;
1241 }
1242
1243 static off_t kcore__write(struct kcore *kcore)
1244 {
1245         return elf_update(kcore->elf, ELF_C_WRITE);
1246 }
1247
1248 struct phdr_data {
1249         off_t offset;
1250         u64 addr;
1251         u64 len;
1252 };
1253
1254 struct kcore_copy_info {
1255         u64 stext;
1256         u64 etext;
1257         u64 first_symbol;
1258         u64 last_symbol;
1259         u64 first_module;
1260         u64 last_module_symbol;
1261         struct phdr_data kernel_map;
1262         struct phdr_data modules_map;
1263 };
1264
1265 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1266                                         u64 start)
1267 {
1268         struct kcore_copy_info *kci = arg;
1269
1270         if (!symbol_type__is_a(type, MAP__FUNCTION))
1271                 return 0;
1272
1273         if (strchr(name, '[')) {
1274                 if (start > kci->last_module_symbol)
1275                         kci->last_module_symbol = start;
1276                 return 0;
1277         }
1278
1279         if (!kci->first_symbol || start < kci->first_symbol)
1280                 kci->first_symbol = start;
1281
1282         if (!kci->last_symbol || start > kci->last_symbol)
1283                 kci->last_symbol = start;
1284
1285         if (!strcmp(name, "_stext")) {
1286                 kci->stext = start;
1287                 return 0;
1288         }
1289
1290         if (!strcmp(name, "_etext")) {
1291                 kci->etext = start;
1292                 return 0;
1293         }
1294
1295         return 0;
1296 }
1297
1298 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1299                                       const char *dir)
1300 {
1301         char kallsyms_filename[PATH_MAX];
1302
1303         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1304
1305         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1306                 return -1;
1307
1308         if (kallsyms__parse(kallsyms_filename, kci,
1309                             kcore_copy__process_kallsyms) < 0)
1310                 return -1;
1311
1312         return 0;
1313 }
1314
1315 static int kcore_copy__process_modules(void *arg,
1316                                        const char *name __maybe_unused,
1317                                        u64 start)
1318 {
1319         struct kcore_copy_info *kci = arg;
1320
1321         if (!kci->first_module || start < kci->first_module)
1322                 kci->first_module = start;
1323
1324         return 0;
1325 }
1326
1327 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1328                                      const char *dir)
1329 {
1330         char modules_filename[PATH_MAX];
1331
1332         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1333
1334         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1335                 return -1;
1336
1337         if (modules__parse(modules_filename, kci,
1338                            kcore_copy__process_modules) < 0)
1339                 return -1;
1340
1341         return 0;
1342 }
1343
1344 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1345                             u64 s, u64 e)
1346 {
1347         if (p->addr || s < start || s >= end)
1348                 return;
1349
1350         p->addr = s;
1351         p->offset = (s - start) + pgoff;
1352         p->len = e < end ? e - s : end - s;
1353 }
1354
1355 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1356 {
1357         struct kcore_copy_info *kci = data;
1358         u64 end = start + len;
1359
1360         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1361                         kci->etext);
1362
1363         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1364                         kci->last_module_symbol);
1365
1366         return 0;
1367 }
1368
1369 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1370 {
1371         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1372                 return -1;
1373
1374         return 0;
1375 }
1376
1377 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1378                                  Elf *elf)
1379 {
1380         if (kcore_copy__parse_kallsyms(kci, dir))
1381                 return -1;
1382
1383         if (kcore_copy__parse_modules(kci, dir))
1384                 return -1;
1385
1386         if (kci->stext)
1387                 kci->stext = round_down(kci->stext, page_size);
1388         else
1389                 kci->stext = round_down(kci->first_symbol, page_size);
1390
1391         if (kci->etext) {
1392                 kci->etext = round_up(kci->etext, page_size);
1393         } else if (kci->last_symbol) {
1394                 kci->etext = round_up(kci->last_symbol, page_size);
1395                 kci->etext += page_size;
1396         }
1397
1398         kci->first_module = round_down(kci->first_module, page_size);
1399
1400         if (kci->last_module_symbol) {
1401                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1402                                                    page_size);
1403                 kci->last_module_symbol += page_size;
1404         }
1405
1406         if (!kci->stext || !kci->etext)
1407                 return -1;
1408
1409         if (kci->first_module && !kci->last_module_symbol)
1410                 return -1;
1411
1412         return kcore_copy__read_maps(kci, elf);
1413 }
1414
1415 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1416                                  const char *name)
1417 {
1418         char from_filename[PATH_MAX];
1419         char to_filename[PATH_MAX];
1420
1421         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1422         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1423
1424         return copyfile_mode(from_filename, to_filename, 0400);
1425 }
1426
1427 static int kcore_copy__unlink(const char *dir, const char *name)
1428 {
1429         char filename[PATH_MAX];
1430
1431         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1432
1433         return unlink(filename);
1434 }
1435
1436 static int kcore_copy__compare_fds(int from, int to)
1437 {
1438         char *buf_from;
1439         char *buf_to;
1440         ssize_t ret;
1441         size_t len;
1442         int err = -1;
1443
1444         buf_from = malloc(page_size);
1445         buf_to = malloc(page_size);
1446         if (!buf_from || !buf_to)
1447                 goto out;
1448
1449         while (1) {
1450                 /* Use read because mmap won't work on proc files */
1451                 ret = read(from, buf_from, page_size);
1452                 if (ret < 0)
1453                         goto out;
1454
1455                 if (!ret)
1456                         break;
1457
1458                 len = ret;
1459
1460                 if (readn(to, buf_to, len) != (int)len)
1461                         goto out;
1462
1463                 if (memcmp(buf_from, buf_to, len))
1464                         goto out;
1465         }
1466
1467         err = 0;
1468 out:
1469         free(buf_to);
1470         free(buf_from);
1471         return err;
1472 }
1473
1474 static int kcore_copy__compare_files(const char *from_filename,
1475                                      const char *to_filename)
1476 {
1477         int from, to, err = -1;
1478
1479         from = open(from_filename, O_RDONLY);
1480         if (from < 0)
1481                 return -1;
1482
1483         to = open(to_filename, O_RDONLY);
1484         if (to < 0)
1485                 goto out_close_from;
1486
1487         err = kcore_copy__compare_fds(from, to);
1488
1489         close(to);
1490 out_close_from:
1491         close(from);
1492         return err;
1493 }
1494
1495 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1496                                     const char *name)
1497 {
1498         char from_filename[PATH_MAX];
1499         char to_filename[PATH_MAX];
1500
1501         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1502         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1503
1504         return kcore_copy__compare_files(from_filename, to_filename);
1505 }
1506
1507 /**
1508  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1509  * @from_dir: from directory
1510  * @to_dir: to directory
1511  *
1512  * This function copies kallsyms, modules and kcore files from one directory to
1513  * another.  kallsyms and modules are copied entirely.  Only code segments are
1514  * copied from kcore.  It is assumed that two segments suffice: one for the
1515  * kernel proper and one for all the modules.  The code segments are determined
1516  * from kallsyms and modules files.  The kernel map starts at _stext or the
1517  * lowest function symbol, and ends at _etext or the highest function symbol.
1518  * The module map starts at the lowest module address and ends at the highest
1519  * module symbol.  Start addresses are rounded down to the nearest page.  End
1520  * addresses are rounded up to the nearest page.  An extra page is added to the
1521  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1522  * symbol too.  Because it contains only code sections, the resulting kcore is
1523  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1524  * is not the same for the kernel map and the modules map.  That happens because
1525  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1526  * kallsyms and modules files are compared with their copies to check that
1527  * modules have not been loaded or unloaded while the copies were taking place.
1528  *
1529  * Return: %0 on success, %-1 on failure.
1530  */
1531 int kcore_copy(const char *from_dir, const char *to_dir)
1532 {
1533         struct kcore kcore;
1534         struct kcore extract;
1535         size_t count = 2;
1536         int idx = 0, err = -1;
1537         off_t offset = page_size, sz, modules_offset = 0;
1538         struct kcore_copy_info kci = { .stext = 0, };
1539         char kcore_filename[PATH_MAX];
1540         char extract_filename[PATH_MAX];
1541
1542         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1543                 return -1;
1544
1545         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1546                 goto out_unlink_kallsyms;
1547
1548         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1549         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1550
1551         if (kcore__open(&kcore, kcore_filename))
1552                 goto out_unlink_modules;
1553
1554         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1555                 goto out_kcore_close;
1556
1557         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1558                 goto out_kcore_close;
1559
1560         if (!kci.modules_map.addr)
1561                 count -= 1;
1562
1563         if (kcore__copy_hdr(&kcore, &extract, count))
1564                 goto out_extract_close;
1565
1566         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1567                             kci.kernel_map.len))
1568                 goto out_extract_close;
1569
1570         if (kci.modules_map.addr) {
1571                 modules_offset = offset + kci.kernel_map.len;
1572                 if (kcore__add_phdr(&extract, idx, modules_offset,
1573                                     kci.modules_map.addr, kci.modules_map.len))
1574                         goto out_extract_close;
1575         }
1576
1577         sz = kcore__write(&extract);
1578         if (sz < 0 || sz > offset)
1579                 goto out_extract_close;
1580
1581         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1582                        kci.kernel_map.len))
1583                 goto out_extract_close;
1584
1585         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1586                                          extract.fd, modules_offset,
1587                                          kci.modules_map.len))
1588                 goto out_extract_close;
1589
1590         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1591                 goto out_extract_close;
1592
1593         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1594                 goto out_extract_close;
1595
1596         err = 0;
1597
1598 out_extract_close:
1599         kcore__close(&extract);
1600         if (err)
1601                 unlink(extract_filename);
1602 out_kcore_close:
1603         kcore__close(&kcore);
1604 out_unlink_modules:
1605         if (err)
1606                 kcore_copy__unlink(to_dir, "modules");
1607 out_unlink_kallsyms:
1608         if (err)
1609                 kcore_copy__unlink(to_dir, "kallsyms");
1610
1611         return err;
1612 }
1613
1614 int kcore_extract__create(struct kcore_extract *kce)
1615 {
1616         struct kcore kcore;
1617         struct kcore extract;
1618         size_t count = 1;
1619         int idx = 0, err = -1;
1620         off_t offset = page_size, sz;
1621
1622         if (kcore__open(&kcore, kce->kcore_filename))
1623                 return -1;
1624
1625         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1626         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1627                 goto out_kcore_close;
1628
1629         if (kcore__copy_hdr(&kcore, &extract, count))
1630                 goto out_extract_close;
1631
1632         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1633                 goto out_extract_close;
1634
1635         sz = kcore__write(&extract);
1636         if (sz < 0 || sz > offset)
1637                 goto out_extract_close;
1638
1639         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1640                 goto out_extract_close;
1641
1642         err = 0;
1643
1644 out_extract_close:
1645         kcore__close(&extract);
1646         if (err)
1647                 unlink(kce->extract_filename);
1648 out_kcore_close:
1649         kcore__close(&kcore);
1650
1651         return err;
1652 }
1653
1654 void kcore_extract__delete(struct kcore_extract *kce)
1655 {
1656         unlink(kce->extract_filename);
1657 }
1658
1659 void symbol__elf_init(void)
1660 {
1661         elf_version(EV_CURRENT);
1662 }