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                sym->st_name != 0 &&
  54                sym->st_shndx != SHN_UNDEF;
  55 }
  56
  57 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  58 {
  59         return elf_sym__type(sym) == STT_OBJECT &&
  60                 sym->st_name != 0 &&
  61                 sym->st_shndx != SHN_UNDEF;
  62 }
  63
  64 static inline int elf_sym__is_label(const GElf_Sym *sym)
  65 {
  66         return elf_sym__type(sym) == STT_NOTYPE &&
  67                 sym->st_name != 0 &&
  68                 sym->st_shndx != SHN_UNDEF &&
  69                 sym->st_shndx != SHN_ABS;
  70 }
  71
  72 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
  73 {
  74         switch (type) {
  75         case MAP__FUNCTION:
  76                 return elf_sym__is_function(sym);
  77         case MAP__VARIABLE:
  78                 return elf_sym__is_object(sym);
  79         default:
  80                 return false;
  81         }
  82 }
  83
  84 static inline const char *elf_sym__name(const GElf_Sym *sym,
  85                                         const Elf_Data *symstrs)
  86 {
  87         return symstrs->d_buf + sym->st_name;
  88 }
  89
  90 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
  91                                         const Elf_Data *secstrs)
  92 {
  93         return secstrs->d_buf + shdr->sh_name;
  94 }
  95
  96 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
  97                                         const Elf_Data *secstrs)
  98 {
  99         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 100 }
 101
 102 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 103                                     const Elf_Data *secstrs)
 104 {
 105         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 106 }
 107
 108 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 109                           enum map_type type)
 110 {
 111         switch (type) {
 112         case MAP__FUNCTION:
 113                 return elf_sec__is_text(shdr, secstrs);
 114         case MAP__VARIABLE:
 115                 return elf_sec__is_data(shdr, secstrs);
 116         default:
 117                 return false;
 118         }
 119 }
 120
 121 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 122 {
 123         Elf_Scn *sec = NULL;
 124         GElf_Shdr shdr;
 125         size_t cnt = 1;
 126
 127         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 128                 gelf_getshdr(sec, &shdr);
 129
 130                 if ((addr >= shdr.sh_addr) &&
 131                     (addr < (shdr.sh_addr + shdr.sh_size)))
 132                         return cnt;
 133
 134                 ++cnt;
 135         }
 136
 137         return -1;
 138 }
 139
 140 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 141                              GElf_Shdr *shp, const char *name, 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 (str && !strcmp(name, str)) {
 156                         if (idx)
 157                                 *idx = cnt;
 158                         return sec;
 159                 }
 160                 ++cnt;
 161         }
 162
 163         return NULL;
 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         err = 0;
 511
 512 out_elf_end:
 513         elf_end(elf);
 514 out_close:
 515         close(fd);
 516 out:
 517         return err;
 518 }
 519
 520 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 521 {
 522         static unsigned int const endian = 1;
 523
 524         dso->needs_swap = DSO_SWAP__NO;
 525
 526         switch (eidata) {
 527         case ELFDATA2LSB:
 528                 /* We are big endian, DSO is little endian. */
 529                 if (*(unsigned char const *)&endian != 1)
 530                         dso->needs_swap = DSO_SWAP__YES;
 531                 break;
 532
 533         case ELFDATA2MSB:
 534                 /* We are little endian, DSO is big endian. */
 535                 if (*(unsigned char const *)&endian != 0)
 536                         dso->needs_swap = DSO_SWAP__YES;
 537                 break;
 538
 539         default:
 540                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 541                 return -EINVAL;
 542         }
 543
 544         return 0;
 545 }
 546
 547 bool symsrc__possibly_runtime(struct symsrc *ss)
 548 {
 549         return ss->dynsym || ss->opdsec;
 550 }
 551
 552 bool symsrc__has_symtab(struct symsrc *ss)
 553 {
 554         return ss->symtab != NULL;
 555 }
 556
 557 void symsrc__destroy(struct symsrc *ss)
 558 {
 559         zfree(&ss->name);
 560         elf_end(ss->elf);
 561         close(ss->fd);
 562 }
 563
 564 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 565                  enum dso_binary_type type)
 566 {
 567         int err = -1;
 568         GElf_Ehdr ehdr;
 569         Elf *elf;
 570         int fd;
 571
 572         fd = open(name, O_RDONLY);
 573         if (fd < 0)
 574                 return -1;
 575
 576         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 577         if (elf == NULL) {
 578                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 579                 goto out_close;
 580         }
 581
 582         if (gelf_getehdr(elf, &ehdr) == NULL) {
 583                 pr_debug("%s: cannot get elf header.\n", __func__);
 584                 goto out_elf_end;
 585         }
 586
 587         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 588                 goto out_elf_end;
 589
 590         /* Always reject images with a mismatched build-id: */
 591         if (dso->has_build_id) {
 592                 u8 build_id[BUILD_ID_SIZE];
 593
 594                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 595                         goto out_elf_end;
 596
 597                 if (!dso__build_id_equal(dso, build_id))
 598                         goto out_elf_end;
 599         }
 600
 601         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 602                         NULL);
 603         if (ss->symshdr.sh_type != SHT_SYMTAB)
 604                 ss->symtab = NULL;
 605
 606         ss->dynsym_idx = 0;
 607         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 608                         &ss->dynsym_idx);
 609         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 610                 ss->dynsym = NULL;
 611
 612         ss->opdidx = 0;
 613         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 614                         &ss->opdidx);
 615         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 616                 ss->opdsec = NULL;
 617
 618         if (dso->kernel == DSO_TYPE_USER) {
 619                 GElf_Shdr shdr;
 620                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 621                                 ehdr.e_type == ET_REL ||
 622                                 is_vdso_map(dso->short_name) ||
 623                                 elf_section_by_name(elf, &ehdr, &shdr,
 624                                                      ".gnu.prelink_undo",
 625                                                      NULL) != NULL);
 626         } else {
 627                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 628                                      ehdr.e_type == ET_REL;
 629         }
 630
 631         ss->name   = strdup(name);
 632         if (!ss->name)
 633                 goto out_elf_end;
 634
 635         ss->elf    = elf;
 636         ss->fd     = fd;
 637         ss->ehdr   = ehdr;
 638         ss->type   = type;
 639
 640         return 0;
 641
 642 out_elf_end:
 643         elf_end(elf);
 644 out_close:
 645         close(fd);
 646         return err;
 647 }
 648
 649 /**
 650  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 651  * @kmap: kernel maps and relocation reference symbol
 652  *
 653  * This function returns %true if we are dealing with the kernel maps and the
 654  * relocation reference symbol has not yet been found.  Otherwise %false is
 655  * returned.
 656  */
 657 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 658 {
 659         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 660                !kmap->ref_reloc_sym->unrelocated_addr;
 661 }
 662
 663 /**
 664  * ref_reloc - kernel relocation offset.
 665  * @kmap: kernel maps and relocation reference symbol
 666  *
 667  * This function returns the offset of kernel addresses as determined by using
 668  * the relocation reference symbol i.e. if the kernel has not been relocated
 669  * then the return value is zero.
 670  */
 671 static u64 ref_reloc(struct kmap *kmap)
 672 {
 673         if (kmap && kmap->ref_reloc_sym &&
 674             kmap->ref_reloc_sym->unrelocated_addr)
 675                 return kmap->ref_reloc_sym->addr -
 676                        kmap->ref_reloc_sym->unrelocated_addr;
 677         return 0;
 678 }
 679
 680 int dso__load_sym(struct dso *dso, struct map *map,
 681                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 682                   symbol_filter_t filter, int kmodule)
 683 {
 684         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 685         struct map *curr_map = map;
 686         struct dso *curr_dso = dso;
 687         Elf_Data *symstrs, *secstrs;
 688         uint32_t nr_syms;
 689         int err = -1;
 690         uint32_t idx;
 691         GElf_Ehdr ehdr;
 692         GElf_Shdr shdr;
 693         Elf_Data *syms, *opddata = NULL;
 694         GElf_Sym sym;
 695         Elf_Scn *sec, *sec_strndx;
 696         Elf *elf;
 697         int nr = 0;
 698         bool remap_kernel = false, adjust_kernel_syms = false;
 699
 700         dso->symtab_type = syms_ss->type;
 701         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 702
 703         /*
 704          * Modules may already have symbols from kallsyms, but those symbols
 705          * have the wrong values for the dso maps, so remove them.
 706          */
 707         if (kmodule && syms_ss->symtab)
 708                 symbols__delete(&dso->symbols[map->type]);
 709
 710         if (!syms_ss->symtab) {
 711                 syms_ss->symtab  = syms_ss->dynsym;
 712                 syms_ss->symshdr = syms_ss->dynshdr;
 713         }
 714
 715         elf = syms_ss->elf;
 716         ehdr = syms_ss->ehdr;
 717         sec = syms_ss->symtab;
 718         shdr = syms_ss->symshdr;
 719
 720         if (runtime_ss->opdsec)
 721                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 722
 723         syms = elf_getdata(sec, NULL);
 724         if (syms == NULL)
 725                 goto out_elf_end;
 726
 727         sec = elf_getscn(elf, shdr.sh_link);
 728         if (sec == NULL)
 729                 goto out_elf_end;
 730
 731         symstrs = elf_getdata(sec, NULL);
 732         if (symstrs == NULL)
 733                 goto out_elf_end;
 734
 735         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
 736         if (sec_strndx == NULL)
 737                 goto out_elf_end;
 738
 739         secstrs = elf_getdata(sec_strndx, NULL);
 740         if (secstrs == NULL)
 741                 goto out_elf_end;
 742
 743         nr_syms = shdr.sh_size / shdr.sh_entsize;
 744
 745         memset(&sym, 0, sizeof(sym));
 746
 747         /*
 748          * The kernel relocation symbol is needed in advance in order to adjust
 749          * kernel maps correctly.
 750          */
 751         if (ref_reloc_sym_not_found(kmap)) {
 752                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 753                         const char *elf_name = elf_sym__name(&sym, symstrs);
 754
 755                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 756                                 continue;
 757                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 758                         map->reloc = kmap->ref_reloc_sym->addr -
 759                                      kmap->ref_reloc_sym->unrelocated_addr;
 760                         break;
 761                 }
 762         }
 763
 764         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 765         /*
 766          * Initial kernel and module mappings do not map to the dso.  For
 767          * function mappings, flag the fixups.
 768          */
 769         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 770                 remap_kernel = true;
 771                 adjust_kernel_syms = dso->adjust_symbols;
 772         }
 773         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 774                 struct symbol *f;
 775                 const char *elf_name = elf_sym__name(&sym, symstrs);
 776                 char *demangled = NULL;
 777                 int is_label = elf_sym__is_label(&sym);
 778                 const char *section_name;
 779                 bool used_opd = false;
 780
 781                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 782                         continue;
 783
 784                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 785                  * don't identify functions, so will confuse the profile
 786                  * output: */
 787                 if (ehdr.e_machine == EM_ARM) {
 788                         if (!strcmp(elf_name, "$a") ||
 789                             !strcmp(elf_name, "$d") ||
 790                             !strcmp(elf_name, "$t"))
 791                                 continue;
 792                 }
 793
 794                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 795                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 796                         u64 *opd = opddata->d_buf + offset;
 797                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 798                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 799                                         sym.st_value);
 800                         used_opd = true;
 801                 }
 802                 /*
 803                  * When loading symbols in a data mapping, ABS symbols (which
 804                  * has a value of SHN_ABS in its st_shndx) failed at
 805                  * elf_getscn().  And it marks the loading as a failure so
 806                  * already loaded symbols cannot be fixed up.
 807                  *
 808                  * I'm not sure what should be done. Just ignore them for now.
 809                  * - Namhyung Kim
 810                  */
 811                 if (sym.st_shndx == SHN_ABS)
 812                         continue;
 813
 814                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 815                 if (!sec)
 816                         goto out_elf_end;
 817
 818                 gelf_getshdr(sec, &shdr);
 819
 820                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 821                         continue;
 822
 823                 section_name = elf_sec__name(&shdr, secstrs);
 824
 825                 /* On ARM, symbols for thumb functions have 1 added to
 826                  * the symbol address as a flag - remove it */
 827                 if ((ehdr.e_machine == EM_ARM) &&
 828                     (map->type == MAP__FUNCTION) &&
 829                     (sym.st_value & 1))
 830                         --sym.st_value;
 831
 832                 if (dso->kernel || kmodule) {
 833                         char dso_name[PATH_MAX];
 834
 835                         /* Adjust symbol to map to file offset */
 836                         if (adjust_kernel_syms)
 837                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 838
 839                         if (strcmp(section_name,
 840                                    (curr_dso->short_name +
 841                                     dso->short_name_len)) == 0)
 842                                 goto new_symbol;
 843
 844                         if (strcmp(section_name, ".text") == 0) {
 845                                 /*
 846                                  * The initial kernel mapping is based on
 847                                  * kallsyms and identity maps.  Overwrite it to
 848                                  * map to the kernel dso.
 849                                  */
 850                                 if (remap_kernel && dso->kernel) {
 851                                         remap_kernel = false;
 852                                         map->start = shdr.sh_addr +
 853                                                      ref_reloc(kmap);
 854                                         map->end = map->start + shdr.sh_size;
 855                                         map->pgoff = shdr.sh_offset;
 856                                         map->map_ip = map__map_ip;
 857                                         map->unmap_ip = map__unmap_ip;
 858                                         /* Ensure maps are correctly ordered */
 859                                         map_groups__remove(kmap->kmaps, map);
 860                                         map_groups__insert(kmap->kmaps, map);
 861                                 }
 862
 863                                 /*
 864                                  * The initial module mapping is based on
 865                                  * /proc/modules mapped to offset zero.
 866                                  * Overwrite it to map to the module dso.
 867                                  */
 868                                 if (remap_kernel && kmodule) {
 869                                         remap_kernel = false;
 870                                         map->pgoff = shdr.sh_offset;
 871                                 }
 872
 873                                 curr_map = map;
 874                                 curr_dso = dso;
 875                                 goto new_symbol;
 876                         }
 877
 878                         if (!kmap)
 879                                 goto new_symbol;
 880
 881                         snprintf(dso_name, sizeof(dso_name),
 882                                  "%s%s", dso->short_name, section_name);
 883
 884                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 885                         if (curr_map == NULL) {
 886                                 u64 start = sym.st_value;
 887
 888                                 if (kmodule)
 889                                         start += map->start + shdr.sh_offset;
 890
 891                                 curr_dso = dso__new(dso_name);
 892                                 if (curr_dso == NULL)
 893                                         goto out_elf_end;
 894                                 curr_dso->kernel = dso->kernel;
 895                                 curr_dso->long_name = dso->long_name;
 896                                 curr_dso->long_name_len = dso->long_name_len;
 897                                 curr_map = map__new2(start, curr_dso,
 898                                                      map->type);
 899                                 if (curr_map == NULL) {
 900                                         dso__delete(curr_dso);
 901                                         goto out_elf_end;
 902                                 }
 903                                 if (adjust_kernel_syms) {
 904                                         curr_map->start = shdr.sh_addr +
 905                                                           ref_reloc(kmap);
 906                                         curr_map->end = curr_map->start +
 907                                                         shdr.sh_size;
 908                                         curr_map->pgoff = shdr.sh_offset;
 909                                 } else {
 910                                         curr_map->map_ip = identity__map_ip;
 911                                         curr_map->unmap_ip = identity__map_ip;
 912                                 }
 913                                 curr_dso->symtab_type = dso->symtab_type;
 914                                 map_groups__insert(kmap->kmaps, curr_map);
 915                                 dsos__add(&dso->node, curr_dso);
 916                                 dso__set_loaded(curr_dso, map->type);
 917                         } else
 918                                 curr_dso = curr_map->dso;
 919
 920                         goto new_symbol;
 921                 }
 922
 923                 if ((used_opd && runtime_ss->adjust_symbols)
 924                                 || (!used_opd && syms_ss->adjust_symbols)) {
 925                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 926                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 927                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 928                                   (u64)shdr.sh_offset);
 929                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 930                 }
 931 new_symbol:
 932                 /*
 933                  * We need to figure out if the object was created from C++ sources
 934                  * DWARF DW_compile_unit has this, but we don't always have access
 935                  * to it...
 936                  */
 937                 if (symbol_conf.demangle) {
 938                         demangled = bfd_demangle(NULL, elf_name,
 939                                                  DMGL_PARAMS | DMGL_ANSI);
 940                         if (demangled != NULL)
 941                                 elf_name = demangled;
 942                 }
 943                 f = symbol__new(sym.st_value, sym.st_size,
 944                                 GELF_ST_BIND(sym.st_info), elf_name);
 945                 free(demangled);
 946                 if (!f)
 947                         goto out_elf_end;
 948
 949                 if (filter && filter(curr_map, f))
 950                         symbol__delete(f);
 951                 else {
 952                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
 953                         nr++;
 954                 }
 955         }
 956
 957         /*
 958          * For misannotated, zeroed, ASM function sizes.
 959          */
 960         if (nr > 0) {
 961                 symbols__fixup_duplicate(&dso->symbols[map->type]);
 962                 symbols__fixup_end(&dso->symbols[map->type]);
 963                 if (kmap) {
 964                         /*
 965                          * We need to fixup this here too because we create new
 966                          * maps here, for things like vsyscall sections.
 967                          */
 968                         __map_groups__fixup_end(kmap->kmaps, map->type);
 969                 }
 970         }
 971         err = nr;
 972 out_elf_end:
 973         return err;
 974 }
 975
 976 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
 977 {
 978         GElf_Phdr phdr;
 979         size_t i, phdrnum;
 980         int err;
 981         u64 sz;
 982
 983         if (elf_getphdrnum(elf, &phdrnum))
 984                 return -1;
 985
 986         for (i = 0; i < phdrnum; i++) {
 987                 if (gelf_getphdr(elf, i, &phdr) == NULL)
 988                         return -1;
 989                 if (phdr.p_type != PT_LOAD)
 990                         continue;
 991                 if (exe) {
 992                         if (!(phdr.p_flags & PF_X))
 993                                 continue;
 994                 } else {
 995                         if (!(phdr.p_flags & PF_R))
 996                                 continue;
 997                 }
 998                 sz = min(phdr.p_memsz, phdr.p_filesz);
 999                 if (!sz)
1000                         continue;
1001                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1002                 if (err)
1003                         return err;
1004         }
1005         return 0;
1006 }
1007
1008 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1009                     bool *is_64_bit)
1010 {
1011         int err;
1012         Elf *elf;
1013
1014         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1015         if (elf == NULL)
1016                 return -1;
1017
1018         if (is_64_bit)
1019                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1020
1021         err = elf_read_maps(elf, exe, mapfn, data);
1022
1023         elf_end(elf);
1024         return err;
1025 }
1026
1027 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1028 {
1029         ssize_t r;
1030         size_t n;
1031         int err = -1;
1032         char *buf = malloc(page_size);
1033
1034         if (buf == NULL)
1035                 return -1;
1036
1037         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1038                 goto out;
1039
1040         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1041                 goto out;
1042
1043         while (len) {
1044                 n = page_size;
1045                 if (len < n)
1046                         n = len;
1047                 /* Use read because mmap won't work on proc files */
1048                 r = read(from, buf, n);
1049                 if (r < 0)
1050                         goto out;
1051                 if (!r)
1052                         break;
1053                 n = r;
1054                 r = write(to, buf, n);
1055                 if (r < 0)
1056                         goto out;
1057                 if ((size_t)r != n)
1058                         goto out;
1059                 len -= n;
1060         }
1061
1062         err = 0;
1063 out:
1064         free(buf);
1065         return err;
1066 }
1067
1068 struct kcore {
1069         int fd;
1070         int elfclass;
1071         Elf *elf;
1072         GElf_Ehdr ehdr;
1073 };
1074
1075 static int kcore__open(struct kcore *kcore, const char *filename)
1076 {
1077         GElf_Ehdr *ehdr;
1078
1079         kcore->fd = open(filename, O_RDONLY);
1080         if (kcore->fd == -1)
1081                 return -1;
1082
1083         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1084         if (!kcore->elf)
1085                 goto out_close;
1086
1087         kcore->elfclass = gelf_getclass(kcore->elf);
1088         if (kcore->elfclass == ELFCLASSNONE)
1089                 goto out_end;
1090
1091         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1092         if (!ehdr)
1093                 goto out_end;
1094
1095         return 0;
1096
1097 out_end:
1098         elf_end(kcore->elf);
1099 out_close:
1100         close(kcore->fd);
1101         return -1;
1102 }
1103
1104 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1105                        bool temp)
1106 {
1107         GElf_Ehdr *ehdr;
1108
1109         kcore->elfclass = elfclass;
1110
1111         if (temp)
1112                 kcore->fd = mkstemp(filename);
1113         else
1114                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1115         if (kcore->fd == -1)
1116                 return -1;
1117
1118         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1119         if (!kcore->elf)
1120                 goto out_close;
1121
1122         if (!gelf_newehdr(kcore->elf, elfclass))
1123                 goto out_end;
1124
1125         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1126         if (!ehdr)
1127                 goto out_end;
1128
1129         return 0;
1130
1131 out_end:
1132         elf_end(kcore->elf);
1133 out_close:
1134         close(kcore->fd);
1135         unlink(filename);
1136         return -1;
1137 }
1138
1139 static void kcore__close(struct kcore *kcore)
1140 {
1141         elf_end(kcore->elf);
1142         close(kcore->fd);
1143 }
1144
1145 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1146 {
1147         GElf_Ehdr *ehdr = &to->ehdr;
1148         GElf_Ehdr *kehdr = &from->ehdr;
1149
1150         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1151         ehdr->e_type      = kehdr->e_type;
1152         ehdr->e_machine   = kehdr->e_machine;
1153         ehdr->e_version   = kehdr->e_version;
1154         ehdr->e_entry     = 0;
1155         ehdr->e_shoff     = 0;
1156         ehdr->e_flags     = kehdr->e_flags;
1157         ehdr->e_phnum     = count;
1158         ehdr->e_shentsize = 0;
1159         ehdr->e_shnum     = 0;
1160         ehdr->e_shstrndx  = 0;
1161
1162         if (from->elfclass == ELFCLASS32) {
1163                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1164                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1165                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1166         } else {
1167                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1168                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1169                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1170         }
1171
1172         if (!gelf_update_ehdr(to->elf, ehdr))
1173                 return -1;
1174
1175         if (!gelf_newphdr(to->elf, count))
1176                 return -1;
1177
1178         return 0;
1179 }
1180
1181 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1182                            u64 addr, u64 len)
1183 {
1184         GElf_Phdr gphdr;
1185         GElf_Phdr *phdr;
1186
1187         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1188         if (!phdr)
1189                 return -1;
1190
1191         phdr->p_type    = PT_LOAD;
1192         phdr->p_flags   = PF_R | PF_W | PF_X;
1193         phdr->p_offset  = offset;
1194         phdr->p_vaddr   = addr;
1195         phdr->p_paddr   = 0;
1196         phdr->p_filesz  = len;
1197         phdr->p_memsz   = len;
1198         phdr->p_align   = page_size;
1199
1200         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1201                 return -1;
1202
1203         return 0;
1204 }
1205
1206 static off_t kcore__write(struct kcore *kcore)
1207 {
1208         return elf_update(kcore->elf, ELF_C_WRITE);
1209 }
1210
1211 struct phdr_data {
1212         off_t offset;
1213         u64 addr;
1214         u64 len;
1215 };
1216
1217 struct kcore_copy_info {
1218         u64 stext;
1219         u64 etext;
1220         u64 first_symbol;
1221         u64 last_symbol;
1222         u64 first_module;
1223         u64 last_module_symbol;
1224         struct phdr_data kernel_map;
1225         struct phdr_data modules_map;
1226 };
1227
1228 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1229                                         u64 start)
1230 {
1231         struct kcore_copy_info *kci = arg;
1232
1233         if (!symbol_type__is_a(type, MAP__FUNCTION))
1234                 return 0;
1235
1236         if (strchr(name, '[')) {
1237                 if (start > kci->last_module_symbol)
1238                         kci->last_module_symbol = start;
1239                 return 0;
1240         }
1241
1242         if (!kci->first_symbol || start < kci->first_symbol)
1243                 kci->first_symbol = start;
1244
1245         if (!kci->last_symbol || start > kci->last_symbol)
1246                 kci->last_symbol = start;
1247
1248         if (!strcmp(name, "_stext")) {
1249                 kci->stext = start;
1250                 return 0;
1251         }
1252
1253         if (!strcmp(name, "_etext")) {
1254                 kci->etext = start;
1255                 return 0;
1256         }
1257
1258         return 0;
1259 }
1260
1261 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1262                                       const char *dir)
1263 {
1264         char kallsyms_filename[PATH_MAX];
1265
1266         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1267
1268         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1269                 return -1;
1270
1271         if (kallsyms__parse(kallsyms_filename, kci,
1272                             kcore_copy__process_kallsyms) < 0)
1273                 return -1;
1274
1275         return 0;
1276 }
1277
1278 static int kcore_copy__process_modules(void *arg,
1279                                        const char *name __maybe_unused,
1280                                        u64 start)
1281 {
1282         struct kcore_copy_info *kci = arg;
1283
1284         if (!kci->first_module || start < kci->first_module)
1285                 kci->first_module = start;
1286
1287         return 0;
1288 }
1289
1290 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1291                                      const char *dir)
1292 {
1293         char modules_filename[PATH_MAX];
1294
1295         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1296
1297         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1298                 return -1;
1299
1300         if (modules__parse(modules_filename, kci,
1301                            kcore_copy__process_modules) < 0)
1302                 return -1;
1303
1304         return 0;
1305 }
1306
1307 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1308                             u64 s, u64 e)
1309 {
1310         if (p->addr || s < start || s >= end)
1311                 return;
1312
1313         p->addr = s;
1314         p->offset = (s - start) + pgoff;
1315         p->len = e < end ? e - s : end - s;
1316 }
1317
1318 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1319 {
1320         struct kcore_copy_info *kci = data;
1321         u64 end = start + len;
1322
1323         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1324                         kci->etext);
1325
1326         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1327                         kci->last_module_symbol);
1328
1329         return 0;
1330 }
1331
1332 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1333 {
1334         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1335                 return -1;
1336
1337         return 0;
1338 }
1339
1340 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1341                                  Elf *elf)
1342 {
1343         if (kcore_copy__parse_kallsyms(kci, dir))
1344                 return -1;
1345
1346         if (kcore_copy__parse_modules(kci, dir))
1347                 return -1;
1348
1349         if (kci->stext)
1350                 kci->stext = round_down(kci->stext, page_size);
1351         else
1352                 kci->stext = round_down(kci->first_symbol, page_size);
1353
1354         if (kci->etext) {
1355                 kci->etext = round_up(kci->etext, page_size);
1356         } else if (kci->last_symbol) {
1357                 kci->etext = round_up(kci->last_symbol, page_size);
1358                 kci->etext += page_size;
1359         }
1360
1361         kci->first_module = round_down(kci->first_module, page_size);
1362
1363         if (kci->last_module_symbol) {
1364                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1365                                                    page_size);
1366                 kci->last_module_symbol += page_size;
1367         }
1368
1369         if (!kci->stext || !kci->etext)
1370                 return -1;
1371
1372         if (kci->first_module && !kci->last_module_symbol)
1373                 return -1;
1374
1375         return kcore_copy__read_maps(kci, elf);
1376 }
1377
1378 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1379                                  const char *name)
1380 {
1381         char from_filename[PATH_MAX];
1382         char to_filename[PATH_MAX];
1383
1384         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1385         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1386
1387         return copyfile_mode(from_filename, to_filename, 0400);
1388 }
1389
1390 static int kcore_copy__unlink(const char *dir, const char *name)
1391 {
1392         char filename[PATH_MAX];
1393
1394         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1395
1396         return unlink(filename);
1397 }
1398
1399 static int kcore_copy__compare_fds(int from, int to)
1400 {
1401         char *buf_from;
1402         char *buf_to;
1403         ssize_t ret;
1404         size_t len;
1405         int err = -1;
1406
1407         buf_from = malloc(page_size);
1408         buf_to = malloc(page_size);
1409         if (!buf_from || !buf_to)
1410                 goto out;
1411
1412         while (1) {
1413                 /* Use read because mmap won't work on proc files */
1414                 ret = read(from, buf_from, page_size);
1415                 if (ret < 0)
1416                         goto out;
1417
1418                 if (!ret)
1419                         break;
1420
1421                 len = ret;
1422
1423                 if (readn(to, buf_to, len) != (int)len)
1424                         goto out;
1425
1426                 if (memcmp(buf_from, buf_to, len))
1427                         goto out;
1428         }
1429
1430         err = 0;
1431 out:
1432         free(buf_to);
1433         free(buf_from);
1434         return err;
1435 }
1436
1437 static int kcore_copy__compare_files(const char *from_filename,
1438                                      const char *to_filename)
1439 {
1440         int from, to, err = -1;
1441
1442         from = open(from_filename, O_RDONLY);
1443         if (from < 0)
1444                 return -1;
1445
1446         to = open(to_filename, O_RDONLY);
1447         if (to < 0)
1448                 goto out_close_from;
1449
1450         err = kcore_copy__compare_fds(from, to);
1451
1452         close(to);
1453 out_close_from:
1454         close(from);
1455         return err;
1456 }
1457
1458 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1459                                     const char *name)
1460 {
1461         char from_filename[PATH_MAX];
1462         char to_filename[PATH_MAX];
1463
1464         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1465         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1466
1467         return kcore_copy__compare_files(from_filename, to_filename);
1468 }
1469
1470 /**
1471  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1472  * @from_dir: from directory
1473  * @to_dir: to directory
1474  *
1475  * This function copies kallsyms, modules and kcore files from one directory to
1476  * another.  kallsyms and modules are copied entirely.  Only code segments are
1477  * copied from kcore.  It is assumed that two segments suffice: one for the
1478  * kernel proper and one for all the modules.  The code segments are determined
1479  * from kallsyms and modules files.  The kernel map starts at _stext or the
1480  * lowest function symbol, and ends at _etext or the highest function symbol.
1481  * The module map starts at the lowest module address and ends at the highest
1482  * module symbol.  Start addresses are rounded down to the nearest page.  End
1483  * addresses are rounded up to the nearest page.  An extra page is added to the
1484  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1485  * symbol too.  Because it contains only code sections, the resulting kcore is
1486  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1487  * is not the same for the kernel map and the modules map.  That happens because
1488  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1489  * kallsyms and modules files are compared with their copies to check that
1490  * modules have not been loaded or unloaded while the copies were taking place.
1491  *
1492  * Return: %0 on success, %-1 on failure.
1493  */
1494 int kcore_copy(const char *from_dir, const char *to_dir)
1495 {
1496         struct kcore kcore;
1497         struct kcore extract;
1498         size_t count = 2;
1499         int idx = 0, err = -1;
1500         off_t offset = page_size, sz, modules_offset = 0;
1501         struct kcore_copy_info kci = { .stext = 0, };
1502         char kcore_filename[PATH_MAX];
1503         char extract_filename[PATH_MAX];
1504
1505         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1506                 return -1;
1507
1508         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1509                 goto out_unlink_kallsyms;
1510
1511         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1512         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1513
1514         if (kcore__open(&kcore, kcore_filename))
1515                 goto out_unlink_modules;
1516
1517         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1518                 goto out_kcore_close;
1519
1520         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1521                 goto out_kcore_close;
1522
1523         if (!kci.modules_map.addr)
1524                 count -= 1;
1525
1526         if (kcore__copy_hdr(&kcore, &extract, count))
1527                 goto out_extract_close;
1528
1529         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1530                             kci.kernel_map.len))
1531                 goto out_extract_close;
1532
1533         if (kci.modules_map.addr) {
1534                 modules_offset = offset + kci.kernel_map.len;
1535                 if (kcore__add_phdr(&extract, idx, modules_offset,
1536                                     kci.modules_map.addr, kci.modules_map.len))
1537                         goto out_extract_close;
1538         }
1539
1540         sz = kcore__write(&extract);
1541         if (sz < 0 || sz > offset)
1542                 goto out_extract_close;
1543
1544         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1545                        kci.kernel_map.len))
1546                 goto out_extract_close;
1547
1548         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1549                                          extract.fd, modules_offset,
1550                                          kci.modules_map.len))
1551                 goto out_extract_close;
1552
1553         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1554                 goto out_extract_close;
1555
1556         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1557                 goto out_extract_close;
1558
1559         err = 0;
1560
1561 out_extract_close:
1562         kcore__close(&extract);
1563         if (err)
1564                 unlink(extract_filename);
1565 out_kcore_close:
1566         kcore__close(&kcore);
1567 out_unlink_modules:
1568         if (err)
1569                 kcore_copy__unlink(to_dir, "modules");
1570 out_unlink_kallsyms:
1571         if (err)
1572                 kcore_copy__unlink(to_dir, "kallsyms");
1573
1574         return err;
1575 }
1576
1577 int kcore_extract__create(struct kcore_extract *kce)
1578 {
1579         struct kcore kcore;
1580         struct kcore extract;
1581         size_t count = 1;
1582         int idx = 0, err = -1;
1583         off_t offset = page_size, sz;
1584
1585         if (kcore__open(&kcore, kce->kcore_filename))
1586                 return -1;
1587
1588         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1589         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1590                 goto out_kcore_close;
1591
1592         if (kcore__copy_hdr(&kcore, &extract, count))
1593                 goto out_extract_close;
1594
1595         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1596                 goto out_extract_close;
1597
1598         sz = kcore__write(&extract);
1599         if (sz < 0 || sz > offset)
1600                 goto out_extract_close;
1601
1602         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1603                 goto out_extract_close;
1604
1605         err = 0;
1606
1607 out_extract_close:
1608         kcore__close(&extract);
1609         if (err)
1610                 unlink(kce->extract_filename);
1611 out_kcore_close:
1612         kcore__close(&kcore);
1613
1614         return err;
1615 }
1616
1617 void kcore_extract__delete(struct kcore_extract *kce)
1618 {
1619         unlink(kce->extract_filename);
1620 }
1621
1622 void symbol__elf_init(void)
1623 {
1624         elf_version(EV_CURRENT);
1625 }