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