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 "machine.h"
  10 #include "vdso.h"
  11 #include <symbol/kallsyms.h>
  12 #include "debug.h"
  13
  14 #ifndef EM_AARCH64
  15 #define EM_AARCH64      183  /* ARM 64 bit */
  16 #endif
  17
  18
  19 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  20 extern char *cplus_demangle(const char *, int);
  21
  22 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  23 {
  24         return cplus_demangle(c, i);
  25 }
  26 #else
  27 #ifdef NO_DEMANGLE
  28 static inline char *bfd_demangle(void __maybe_unused *v,
  29                                  const char __maybe_unused *c,
  30                                  int __maybe_unused i)
  31 {
  32         return NULL;
  33 }
  34 #else
  35 #define PACKAGE 'perf'
  36 #include <bfd.h>
  37 #endif
  38 #endif
  39
  40 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  41 static int elf_getphdrnum(Elf *elf, size_t *dst)
  42 {
  43         GElf_Ehdr gehdr;
  44         GElf_Ehdr *ehdr;
  45
  46         ehdr = gelf_getehdr(elf, &gehdr);
  47         if (!ehdr)
  48                 return -1;
  49
  50         *dst = ehdr->e_phnum;
  51
  52         return 0;
  53 }
  54 #endif
  55
  56 #ifndef NT_GNU_BUILD_ID
  57 #define NT_GNU_BUILD_ID 3
  58 #endif
  59
  60 /**
  61  * elf_symtab__for_each_symbol - iterate thru all the symbols
  62  *
  63  * @syms: struct elf_symtab instance to iterate
  64  * @idx: uint32_t idx
  65  * @sym: GElf_Sym iterator
  66  */
  67 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  68         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  69              idx < nr_syms; \
  70              idx++, gelf_getsym(syms, idx, &sym))
  71
  72 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  73 {
  74         return GELF_ST_TYPE(sym->st_info);
  75 }
  76
  77 #ifndef STT_GNU_IFUNC
  78 #define STT_GNU_IFUNC 10
  79 #endif
  80
  81 static inline int elf_sym__is_function(const GElf_Sym *sym)
  82 {
  83         return (elf_sym__type(sym) == STT_FUNC ||
  84                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  85                sym->st_name != 0 &&
  86                sym->st_shndx != SHN_UNDEF;
  87 }
  88
  89 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  90 {
  91         return elf_sym__type(sym) == STT_OBJECT &&
  92                 sym->st_name != 0 &&
  93                 sym->st_shndx != SHN_UNDEF;
  94 }
  95
  96 static inline int elf_sym__is_label(const GElf_Sym *sym)
  97 {
  98         return elf_sym__type(sym) == STT_NOTYPE &&
  99                 sym->st_name != 0 &&
 100                 sym->st_shndx != SHN_UNDEF &&
 101                 sym->st_shndx != SHN_ABS;
 102 }
 103
 104 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
 105 {
 106         switch (type) {
 107         case MAP__FUNCTION:
 108                 return elf_sym__is_function(sym);
 109         case MAP__VARIABLE:
 110                 return elf_sym__is_object(sym);
 111         default:
 112                 return false;
 113         }
 114 }
 115
 116 static inline const char *elf_sym__name(const GElf_Sym *sym,
 117                                         const Elf_Data *symstrs)
 118 {
 119         return symstrs->d_buf + sym->st_name;
 120 }
 121
 122 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 123                                         const Elf_Data *secstrs)
 124 {
 125         return secstrs->d_buf + shdr->sh_name;
 126 }
 127
 128 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 129                                         const Elf_Data *secstrs)
 130 {
 131         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 132 }
 133
 134 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 135                                     const Elf_Data *secstrs)
 136 {
 137         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 138 }
 139
 140 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 141                           enum map_type type)
 142 {
 143         switch (type) {
 144         case MAP__FUNCTION:
 145                 return elf_sec__is_text(shdr, secstrs);
 146         case MAP__VARIABLE:
 147                 return elf_sec__is_data(shdr, secstrs);
 148         default:
 149                 return false;
 150         }
 151 }
 152
 153 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 154 {
 155         Elf_Scn *sec = NULL;
 156         GElf_Shdr shdr;
 157         size_t cnt = 1;
 158
 159         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 160                 gelf_getshdr(sec, &shdr);
 161
 162                 if ((addr >= shdr.sh_addr) &&
 163                     (addr < (shdr.sh_addr + shdr.sh_size)))
 164                         return cnt;
 165
 166                 ++cnt;
 167         }
 168
 169         return -1;
 170 }
 171
 172 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 173                              GElf_Shdr *shp, const char *name, size_t *idx)
 174 {
 175         Elf_Scn *sec = NULL;
 176         size_t cnt = 1;
 177
 178         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 179         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 180                 return NULL;
 181
 182         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 183                 char *str;
 184
 185                 gelf_getshdr(sec, shp);
 186                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 187                 if (str && !strcmp(name, str)) {
 188                         if (idx)
 189                                 *idx = cnt;
 190                         return sec;
 191                 }
 192                 ++cnt;
 193         }
 194
 195         return NULL;
 196 }
 197
 198 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 199         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 200              idx < nr_entries; \
 201              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 202
 203 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 204         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 205              idx < nr_entries; \
 206              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 207
 208 /*
 209  * We need to check if we have a .dynsym, so that we can handle the
 210  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 211  * .dynsym or .symtab).
 212  * And always look at the original dso, not at debuginfo packages, that
 213  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 214  */
 215 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 216                                 symbol_filter_t filter)
 217 {
 218         uint32_t nr_rel_entries, idx;
 219         GElf_Sym sym;
 220         u64 plt_offset;
 221         GElf_Shdr shdr_plt;
 222         struct symbol *f;
 223         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 224         Elf_Data *reldata, *syms, *symstrs;
 225         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 226         size_t dynsym_idx;
 227         GElf_Ehdr ehdr;
 228         char sympltname[1024];
 229         Elf *elf;
 230         int nr = 0, symidx, err = 0;
 231
 232         if (!ss->dynsym)
 233                 return 0;
 234
 235         elf = ss->elf;
 236         ehdr = ss->ehdr;
 237
 238         scn_dynsym = ss->dynsym;
 239         shdr_dynsym = ss->dynshdr;
 240         dynsym_idx = ss->dynsym_idx;
 241
 242         if (scn_dynsym == NULL)
 243                 goto out_elf_end;
 244
 245         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 246                                           ".rela.plt", NULL);
 247         if (scn_plt_rel == NULL) {
 248                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 249                                                   ".rel.plt", NULL);
 250                 if (scn_plt_rel == NULL)
 251                         goto out_elf_end;
 252         }
 253
 254         err = -1;
 255
 256         if (shdr_rel_plt.sh_link != dynsym_idx)
 257                 goto out_elf_end;
 258
 259         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 260                 goto out_elf_end;
 261
 262         /*
 263          * Fetch the relocation section to find the idxes to the GOT
 264          * and the symbols in the .dynsym they refer to.
 265          */
 266         reldata = elf_getdata(scn_plt_rel, NULL);
 267         if (reldata == NULL)
 268                 goto out_elf_end;
 269
 270         syms = elf_getdata(scn_dynsym, NULL);
 271         if (syms == NULL)
 272                 goto out_elf_end;
 273
 274         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 275         if (scn_symstrs == NULL)
 276                 goto out_elf_end;
 277
 278         symstrs = elf_getdata(scn_symstrs, NULL);
 279         if (symstrs == NULL)
 280                 goto out_elf_end;
 281
 282         if (symstrs->d_size == 0)
 283                 goto out_elf_end;
 284
 285         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 286         plt_offset = shdr_plt.sh_offset;
 287
 288         if (shdr_rel_plt.sh_type == SHT_RELA) {
 289                 GElf_Rela pos_mem, *pos;
 290
 291                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 292                                            nr_rel_entries) {
 293                         symidx = GELF_R_SYM(pos->r_info);
 294                         plt_offset += shdr_plt.sh_entsize;
 295                         gelf_getsym(syms, symidx, &sym);
 296                         snprintf(sympltname, sizeof(sympltname),
 297                                  "%s@plt", elf_sym__name(&sym, symstrs));
 298
 299                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 300                                         STB_GLOBAL, sympltname);
 301                         if (!f)
 302                                 goto out_elf_end;
 303
 304                         if (filter && filter(map, f))
 305                                 symbol__delete(f);
 306                         else {
 307                                 symbols__insert(&dso->symbols[map->type], f);
 308                                 ++nr;
 309                         }
 310                 }
 311         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 312                 GElf_Rel pos_mem, *pos;
 313                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 314                                           nr_rel_entries) {
 315                         symidx = GELF_R_SYM(pos->r_info);
 316                         plt_offset += shdr_plt.sh_entsize;
 317                         gelf_getsym(syms, symidx, &sym);
 318                         snprintf(sympltname, sizeof(sympltname),
 319                                  "%s@plt", elf_sym__name(&sym, symstrs));
 320
 321                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 322                                         STB_GLOBAL, sympltname);
 323                         if (!f)
 324                                 goto out_elf_end;
 325
 326                         if (filter && filter(map, f))
 327                                 symbol__delete(f);
 328                         else {
 329                                 symbols__insert(&dso->symbols[map->type], f);
 330                                 ++nr;
 331                         }
 332                 }
 333         }
 334
 335         err = 0;
 336 out_elf_end:
 337         if (err == 0)
 338                 return nr;
 339         pr_debug("%s: problems reading %s PLT info.\n",
 340                  __func__, dso->long_name);
 341         return 0;
 342 }
 343
 344 /*
 345  * Align offset to 4 bytes as needed for note name and descriptor data.
 346  */
 347 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 348
 349 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 350 {
 351         int err = -1;
 352         GElf_Ehdr ehdr;
 353         GElf_Shdr shdr;
 354         Elf_Data *data;
 355         Elf_Scn *sec;
 356         Elf_Kind ek;
 357         void *ptr;
 358
 359         if (size < BUILD_ID_SIZE)
 360                 goto out;
 361
 362         ek = elf_kind(elf);
 363         if (ek != ELF_K_ELF)
 364                 goto out;
 365
 366         if (gelf_getehdr(elf, &ehdr) == NULL) {
 367                 pr_err("%s: cannot get elf header.\n", __func__);
 368                 goto out;
 369         }
 370
 371         /*
 372          * Check following sections for notes:
 373          *   '.note.gnu.build-id'
 374          *   '.notes'
 375          *   '.note' (VDSO specific)
 376          */
 377         do {
 378                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 379                                           ".note.gnu.build-id", NULL);
 380                 if (sec)
 381                         break;
 382
 383                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 384                                           ".notes", NULL);
 385                 if (sec)
 386                         break;
 387
 388                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 389                                           ".note", NULL);
 390                 if (sec)
 391                         break;
 392
 393                 return err;
 394
 395         } while (0);
 396
 397         data = elf_getdata(sec, NULL);
 398         if (data == NULL)
 399                 goto out;
 400
 401         ptr = data->d_buf;
 402         while (ptr < (data->d_buf + data->d_size)) {
 403                 GElf_Nhdr *nhdr = ptr;
 404                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 405                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 406                 const char *name;
 407
 408                 ptr += sizeof(*nhdr);
 409                 name = ptr;
 410                 ptr += namesz;
 411                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 412                     nhdr->n_namesz == sizeof("GNU")) {
 413                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 414                                 size_t sz = min(size, descsz);
 415                                 memcpy(bf, ptr, sz);
 416                                 memset(bf + sz, 0, size - sz);
 417                                 err = descsz;
 418                                 break;
 419                         }
 420                 }
 421                 ptr += descsz;
 422         }
 423
 424 out:
 425         return err;
 426 }
 427
 428 int filename__read_build_id(const char *filename, void *bf, size_t size)
 429 {
 430         int fd, err = -1;
 431         Elf *elf;
 432
 433         if (size < BUILD_ID_SIZE)
 434                 goto out;
 435
 436         fd = open(filename, O_RDONLY);
 437         if (fd < 0)
 438                 goto out;
 439
 440         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 441         if (elf == NULL) {
 442                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 443                 goto out_close;
 444         }
 445
 446         err = elf_read_build_id(elf, bf, size);
 447
 448         elf_end(elf);
 449 out_close:
 450         close(fd);
 451 out:
 452         return err;
 453 }
 454
 455 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 456 {
 457         int fd, err = -1;
 458
 459         if (size < BUILD_ID_SIZE)
 460                 goto out;
 461
 462         fd = open(filename, O_RDONLY);
 463         if (fd < 0)
 464                 goto out;
 465
 466         while (1) {
 467                 char bf[BUFSIZ];
 468                 GElf_Nhdr nhdr;
 469                 size_t namesz, descsz;
 470
 471                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 472                         break;
 473
 474                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 475                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 476                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 477                     nhdr.n_namesz == sizeof("GNU")) {
 478                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 479                                 break;
 480                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 481                                 size_t sz = min(descsz, size);
 482                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 483                                         memset(build_id + sz, 0, size - sz);
 484                                         err = 0;
 485                                         break;
 486                                 }
 487                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 488                                 break;
 489                 } else {
 490                         int n = namesz + descsz;
 491                         if (read(fd, bf, n) != n)
 492                                 break;
 493                 }
 494         }
 495         close(fd);
 496 out:
 497         return err;
 498 }
 499
 500 int filename__read_debuglink(const char *filename, char *debuglink,
 501                              size_t size)
 502 {
 503         int fd, err = -1;
 504         Elf *elf;
 505         GElf_Ehdr ehdr;
 506         GElf_Shdr shdr;
 507         Elf_Data *data;
 508         Elf_Scn *sec;
 509         Elf_Kind ek;
 510
 511         fd = open(filename, O_RDONLY);
 512         if (fd < 0)
 513                 goto out;
 514
 515         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 516         if (elf == NULL) {
 517                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 518                 goto out_close;
 519         }
 520
 521         ek = elf_kind(elf);
 522         if (ek != ELF_K_ELF)
 523                 goto out_elf_end;
 524
 525         if (gelf_getehdr(elf, &ehdr) == NULL) {
 526                 pr_err("%s: cannot get elf header.\n", __func__);
 527                 goto out_elf_end;
 528         }
 529
 530         sec = elf_section_by_name(elf, &ehdr, &shdr,
 531                                   ".gnu_debuglink", NULL);
 532         if (sec == NULL)
 533                 goto out_elf_end;
 534
 535         data = elf_getdata(sec, NULL);
 536         if (data == NULL)
 537                 goto out_elf_end;
 538
 539         /* the start of this section is a zero-terminated string */
 540         strncpy(debuglink, data->d_buf, size);
 541
 542         err = 0;
 543
 544 out_elf_end:
 545         elf_end(elf);
 546 out_close:
 547         close(fd);
 548 out:
 549         return err;
 550 }
 551
 552 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 553 {
 554         static unsigned int const endian = 1;
 555
 556         dso->needs_swap = DSO_SWAP__NO;
 557
 558         switch (eidata) {
 559         case ELFDATA2LSB:
 560                 /* We are big endian, DSO is little endian. */
 561                 if (*(unsigned char const *)&endian != 1)
 562                         dso->needs_swap = DSO_SWAP__YES;
 563                 break;
 564
 565         case ELFDATA2MSB:
 566                 /* We are little endian, DSO is big endian. */
 567                 if (*(unsigned char const *)&endian != 0)
 568                         dso->needs_swap = DSO_SWAP__YES;
 569                 break;
 570
 571         default:
 572                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 573                 return -EINVAL;
 574         }
 575
 576         return 0;
 577 }
 578
 579 static int decompress_kmodule(struct dso *dso, const char *name,
 580                               enum dso_binary_type type)
 581 {
 582         int fd = -1;
 583         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 584         struct kmod_path m;
 585
 586         if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
 587             type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
 588             type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
 589                 return -1;
 590
 591         if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
 592                 name = dso->long_name;
 593
 594         if (kmod_path__parse_ext(&m, name) || !m.comp)
 595                 return -1;
 596
 597         fd = mkstemp(tmpbuf);
 598         if (fd < 0) {
 599                 dso->load_errno = errno;
 600                 goto out;
 601         }
 602
 603         if (!decompress_to_file(m.ext, name, fd)) {
 604                 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
 605                 close(fd);
 606                 fd = -1;
 607         }
 608
 609         unlink(tmpbuf);
 610
 611 out:
 612         free(m.ext);
 613         return fd;
 614 }
 615
 616 bool symsrc__possibly_runtime(struct symsrc *ss)
 617 {
 618         return ss->dynsym || ss->opdsec;
 619 }
 620
 621 bool symsrc__has_symtab(struct symsrc *ss)
 622 {
 623         return ss->symtab != NULL;
 624 }
 625
 626 void symsrc__destroy(struct symsrc *ss)
 627 {
 628         zfree(&ss->name);
 629         elf_end(ss->elf);
 630         close(ss->fd);
 631 }
 632
 633 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 634 {
 635         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 636 }
 637
 638 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 639                  enum dso_binary_type type)
 640 {
 641         int err = -1;
 642         GElf_Ehdr ehdr;
 643         Elf *elf;
 644         int fd;
 645
 646         if (dso__needs_decompress(dso)) {
 647                 fd = decompress_kmodule(dso, name, type);
 648                 if (fd < 0)
 649                         return -1;
 650         } else {
 651                 fd = open(name, O_RDONLY);
 652                 if (fd < 0) {
 653                         dso->load_errno = errno;
 654                         return -1;
 655                 }
 656         }
 657
 658         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 659         if (elf == NULL) {
 660                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 661                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 662                 goto out_close;
 663         }
 664
 665         if (gelf_getehdr(elf, &ehdr) == NULL) {
 666                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 667                 pr_debug("%s: cannot get elf header.\n", __func__);
 668                 goto out_elf_end;
 669         }
 670
 671         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 672                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 673                 goto out_elf_end;
 674         }
 675
 676         /* Always reject images with a mismatched build-id: */
 677         if (dso->has_build_id) {
 678                 u8 build_id[BUILD_ID_SIZE];
 679
 680                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 681                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 682                         goto out_elf_end;
 683                 }
 684
 685                 if (!dso__build_id_equal(dso, build_id)) {
 686                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 687                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 688                         goto out_elf_end;
 689                 }
 690         }
 691
 692         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 693
 694         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 695                         NULL);
 696         if (ss->symshdr.sh_type != SHT_SYMTAB)
 697                 ss->symtab = NULL;
 698
 699         ss->dynsym_idx = 0;
 700         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 701                         &ss->dynsym_idx);
 702         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 703                 ss->dynsym = NULL;
 704
 705         ss->opdidx = 0;
 706         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 707                         &ss->opdidx);
 708         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 709                 ss->opdsec = NULL;
 710
 711         if (dso->kernel == DSO_TYPE_USER) {
 712                 GElf_Shdr shdr;
 713                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 714                                 ehdr.e_type == ET_REL ||
 715                                 dso__is_vdso(dso) ||
 716                                 elf_section_by_name(elf, &ehdr, &shdr,
 717                                                      ".gnu.prelink_undo",
 718                                                      NULL) != NULL);
 719         } else {
 720                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 721         }
 722
 723         ss->name   = strdup(name);
 724         if (!ss->name) {
 725                 dso->load_errno = errno;
 726                 goto out_elf_end;
 727         }
 728
 729         ss->elf    = elf;
 730         ss->fd     = fd;
 731         ss->ehdr   = ehdr;
 732         ss->type   = type;
 733
 734         return 0;
 735
 736 out_elf_end:
 737         elf_end(elf);
 738 out_close:
 739         close(fd);
 740         return err;
 741 }
 742
 743 /**
 744  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 745  * @kmap: kernel maps and relocation reference symbol
 746  *
 747  * This function returns %true if we are dealing with the kernel maps and the
 748  * relocation reference symbol has not yet been found.  Otherwise %false is
 749  * returned.
 750  */
 751 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 752 {
 753         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 754                !kmap->ref_reloc_sym->unrelocated_addr;
 755 }
 756
 757 /**
 758  * ref_reloc - kernel relocation offset.
 759  * @kmap: kernel maps and relocation reference symbol
 760  *
 761  * This function returns the offset of kernel addresses as determined by using
 762  * the relocation reference symbol i.e. if the kernel has not been relocated
 763  * then the return value is zero.
 764  */
 765 static u64 ref_reloc(struct kmap *kmap)
 766 {
 767         if (kmap && kmap->ref_reloc_sym &&
 768             kmap->ref_reloc_sym->unrelocated_addr)
 769                 return kmap->ref_reloc_sym->addr -
 770                        kmap->ref_reloc_sym->unrelocated_addr;
 771         return 0;
 772 }
 773
 774 static bool want_demangle(bool is_kernel_sym)
 775 {
 776         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 777 }
 778
 779 void __weak arch__elf_sym_adjust(GElf_Sym *sym __maybe_unused) { }
 780
 781 int dso__load_sym(struct dso *dso, struct map *map,
 782                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 783                   symbol_filter_t filter, int kmodule)
 784 {
 785         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 786         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 787         struct map *curr_map = map;
 788         struct dso *curr_dso = dso;
 789         Elf_Data *symstrs, *secstrs;
 790         uint32_t nr_syms;
 791         int err = -1;
 792         uint32_t idx;
 793         GElf_Ehdr ehdr;
 794         GElf_Shdr shdr;
 795         Elf_Data *syms, *opddata = NULL;
 796         GElf_Sym sym;
 797         Elf_Scn *sec, *sec_strndx;
 798         Elf *elf;
 799         int nr = 0;
 800         bool remap_kernel = false, adjust_kernel_syms = false;
 801
 802         if (kmap && !kmaps)
 803                 return -1;
 804
 805         dso->symtab_type = syms_ss->type;
 806         dso->is_64_bit = syms_ss->is_64_bit;
 807         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 808
 809         /*
 810          * Modules may already have symbols from kallsyms, but those symbols
 811          * have the wrong values for the dso maps, so remove them.
 812          */
 813         if (kmodule && syms_ss->symtab)
 814                 symbols__delete(&dso->symbols[map->type]);
 815
 816         if (!syms_ss->symtab) {
 817                 /*
 818                  * If the vmlinux is stripped, fail so we will fall back
 819                  * to using kallsyms. The vmlinux runtime symbols aren't
 820                  * of much use.
 821                  */
 822                 if (dso->kernel)
 823                         goto out_elf_end;
 824
 825                 syms_ss->symtab  = syms_ss->dynsym;
 826                 syms_ss->symshdr = syms_ss->dynshdr;
 827         }
 828
 829         elf = syms_ss->elf;
 830         ehdr = syms_ss->ehdr;
 831         sec = syms_ss->symtab;
 832         shdr = syms_ss->symshdr;
 833
 834         if (runtime_ss->opdsec)
 835                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 836
 837         syms = elf_getdata(sec, NULL);
 838         if (syms == NULL)
 839                 goto out_elf_end;
 840
 841         sec = elf_getscn(elf, shdr.sh_link);
 842         if (sec == NULL)
 843                 goto out_elf_end;
 844
 845         symstrs = elf_getdata(sec, NULL);
 846         if (symstrs == NULL)
 847                 goto out_elf_end;
 848
 849         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 850         if (sec_strndx == NULL)
 851                 goto out_elf_end;
 852
 853         secstrs = elf_getdata(sec_strndx, NULL);
 854         if (secstrs == NULL)
 855                 goto out_elf_end;
 856
 857         nr_syms = shdr.sh_size / shdr.sh_entsize;
 858
 859         memset(&sym, 0, sizeof(sym));
 860
 861         /*
 862          * The kernel relocation symbol is needed in advance in order to adjust
 863          * kernel maps correctly.
 864          */
 865         if (ref_reloc_sym_not_found(kmap)) {
 866                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 867                         const char *elf_name = elf_sym__name(&sym, symstrs);
 868
 869                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 870                                 continue;
 871                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 872                         map->reloc = kmap->ref_reloc_sym->addr -
 873                                      kmap->ref_reloc_sym->unrelocated_addr;
 874                         break;
 875                 }
 876         }
 877
 878         /*
 879          * Handle any relocation of vdso necessary because older kernels
 880          * attempted to prelink vdso to its virtual address.
 881          */
 882         if (dso__is_vdso(dso)) {
 883                 GElf_Shdr tshdr;
 884
 885                 if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
 886                         map->reloc = map->start - tshdr.sh_addr + tshdr.sh_offset;
 887         }
 888
 889         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 890         /*
 891          * Initial kernel and module mappings do not map to the dso.  For
 892          * function mappings, flag the fixups.
 893          */
 894         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 895                 remap_kernel = true;
 896                 adjust_kernel_syms = dso->adjust_symbols;
 897         }
 898         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 899                 struct symbol *f;
 900                 const char *elf_name = elf_sym__name(&sym, symstrs);
 901                 char *demangled = NULL;
 902                 int is_label = elf_sym__is_label(&sym);
 903                 const char *section_name;
 904                 bool used_opd = false;
 905
 906                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 907                         continue;
 908
 909                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 910                  * don't identify functions, so will confuse the profile
 911                  * output: */
 912                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 913                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 914                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 915                                 continue;
 916                 }
 917
 918                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 919                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 920                         u64 *opd = opddata->d_buf + offset;
 921                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 922                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 923                                         sym.st_value);
 924                         used_opd = true;
 925                 }
 926                 /*
 927                  * When loading symbols in a data mapping, ABS symbols (which
 928                  * has a value of SHN_ABS in its st_shndx) failed at
 929                  * elf_getscn().  And it marks the loading as a failure so
 930                  * already loaded symbols cannot be fixed up.
 931                  *
 932                  * I'm not sure what should be done. Just ignore them for now.
 933                  * - Namhyung Kim
 934                  */
 935                 if (sym.st_shndx == SHN_ABS)
 936                         continue;
 937
 938                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 939                 if (!sec)
 940                         goto out_elf_end;
 941
 942                 gelf_getshdr(sec, &shdr);
 943
 944                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 945                         continue;
 946
 947                 section_name = elf_sec__name(&shdr, secstrs);
 948
 949                 /* On ARM, symbols for thumb functions have 1 added to
 950                  * the symbol address as a flag - remove it */
 951                 if ((ehdr.e_machine == EM_ARM) &&
 952                     (map->type == MAP__FUNCTION) &&
 953                     (sym.st_value & 1))
 954                         --sym.st_value;
 955
 956                 arch__elf_sym_adjust(&sym);
 957
 958                 if (dso->kernel || kmodule) {
 959                         char dso_name[PATH_MAX];
 960
 961                         /* Adjust symbol to map to file offset */
 962                         if (adjust_kernel_syms)
 963                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 964
 965                         if (strcmp(section_name,
 966                                    (curr_dso->short_name +
 967                                     dso->short_name_len)) == 0)
 968                                 goto new_symbol;
 969
 970                         if (strcmp(section_name, ".text") == 0) {
 971                                 /*
 972                                  * The initial kernel mapping is based on
 973                                  * kallsyms and identity maps.  Overwrite it to
 974                                  * map to the kernel dso.
 975                                  */
 976                                 if (remap_kernel && dso->kernel) {
 977                                         remap_kernel = false;
 978                                         map->start = shdr.sh_addr +
 979                                                      ref_reloc(kmap);
 980                                         map->end = map->start + shdr.sh_size;
 981                                         map->pgoff = shdr.sh_offset;
 982                                         map->map_ip = map__map_ip;
 983                                         map->unmap_ip = map__unmap_ip;
 984                                         /* Ensure maps are correctly ordered */
 985                                         if (kmaps) {
 986                                                 map__get(map);
 987                                                 map_groups__remove(kmaps, map);
 988                                                 map_groups__insert(kmaps, map);
 989                                                 map__put(map);
 990                                         }
 991                                 }
 992
 993                                 /*
 994                                  * The initial module mapping is based on
 995                                  * /proc/modules mapped to offset zero.
 996                                  * Overwrite it to map to the module dso.
 997                                  */
 998                                 if (remap_kernel && kmodule) {
 999                                         remap_kernel = false;
1000                                         map->pgoff = shdr.sh_offset;
1001                                 }
1002
1003                                 curr_map = map;
1004                                 curr_dso = dso;
1005                                 goto new_symbol;
1006                         }
1007
1008                         if (!kmap)
1009                                 goto new_symbol;
1010
1011                         snprintf(dso_name, sizeof(dso_name),
1012                                  "%s%s", dso->short_name, section_name);
1013
1014                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1015                         if (curr_map == NULL) {
1016                                 u64 start = sym.st_value;
1017
1018                                 if (kmodule)
1019                                         start += map->start + shdr.sh_offset;
1020
1021                                 curr_dso = dso__new(dso_name);
1022                                 if (curr_dso == NULL)
1023                                         goto out_elf_end;
1024                                 curr_dso->kernel = dso->kernel;
1025                                 curr_dso->long_name = dso->long_name;
1026                                 curr_dso->long_name_len = dso->long_name_len;
1027                                 curr_map = map__new2(start, curr_dso,
1028                                                      map->type);
1029                                 dso__put(curr_dso);
1030                                 if (curr_map == NULL) {
1031                                         goto out_elf_end;
1032                                 }
1033                                 if (adjust_kernel_syms) {
1034                                         curr_map->start = shdr.sh_addr +
1035                                                           ref_reloc(kmap);
1036                                         curr_map->end = curr_map->start +
1037                                                         shdr.sh_size;
1038                                         curr_map->pgoff = shdr.sh_offset;
1039                                 } else {
1040                                         curr_map->map_ip = identity__map_ip;
1041                                         curr_map->unmap_ip = identity__map_ip;
1042                                 }
1043                                 curr_dso->symtab_type = dso->symtab_type;
1044                                 map_groups__insert(kmaps, curr_map);
1045                                 /*
1046                                  * Add it before we drop the referece to curr_map,
1047                                  * i.e. while we still are sure to have a reference
1048                                  * to this DSO via curr_map->dso.
1049                                  */
1050                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1051                                 /* kmaps already got it */
1052                                 map__put(curr_map);
1053                                 dso__set_loaded(curr_dso, map->type);
1054                         } else
1055                                 curr_dso = curr_map->dso;
1056
1057                         goto new_symbol;
1058                 }
1059
1060                 if ((used_opd && runtime_ss->adjust_symbols)
1061                                 || (!used_opd && syms_ss->adjust_symbols)) {
1062                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1063                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1064                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1065                                   (u64)shdr.sh_offset);
1066                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1067                 }
1068 new_symbol:
1069                 /*
1070                  * We need to figure out if the object was created from C++ sources
1071                  * DWARF DW_compile_unit has this, but we don't always have access
1072                  * to it...
1073                  */
1074                 if (want_demangle(dso->kernel || kmodule)) {
1075                         int demangle_flags = DMGL_NO_OPTS;
1076                         if (verbose)
1077                                 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1078
1079                         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1080                         if (demangled != NULL)
1081                                 elf_name = demangled;
1082                 }
1083                 f = symbol__new(sym.st_value, sym.st_size,
1084                                 GELF_ST_BIND(sym.st_info), elf_name);
1085                 free(demangled);
1086                 if (!f)
1087                         goto out_elf_end;
1088
1089                 if (filter && filter(curr_map, f))
1090                         symbol__delete(f);
1091                 else {
1092                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
1093                         nr++;
1094                 }
1095         }
1096
1097         /*
1098          * For misannotated, zeroed, ASM function sizes.
1099          */
1100         if (nr > 0) {
1101                 if (!symbol_conf.allow_aliases)
1102                         symbols__fixup_duplicate(&dso->symbols[map->type]);
1103                 symbols__fixup_end(&dso->symbols[map->type]);
1104                 if (kmap) {
1105                         /*
1106                          * We need to fixup this here too because we create new
1107                          * maps here, for things like vsyscall sections.
1108                          */
1109                         __map_groups__fixup_end(kmaps, map->type);
1110                 }
1111         }
1112         err = nr;
1113 out_elf_end:
1114         return err;
1115 }
1116
1117 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1118 {
1119         GElf_Phdr phdr;
1120         size_t i, phdrnum;
1121         int err;
1122         u64 sz;
1123
1124         if (elf_getphdrnum(elf, &phdrnum))
1125                 return -1;
1126
1127         for (i = 0; i < phdrnum; i++) {
1128                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1129                         return -1;
1130                 if (phdr.p_type != PT_LOAD)
1131                         continue;
1132                 if (exe) {
1133                         if (!(phdr.p_flags & PF_X))
1134                                 continue;
1135                 } else {
1136                         if (!(phdr.p_flags & PF_R))
1137                                 continue;
1138                 }
1139                 sz = min(phdr.p_memsz, phdr.p_filesz);
1140                 if (!sz)
1141                         continue;
1142                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1143                 if (err)
1144                         return err;
1145         }
1146         return 0;
1147 }
1148
1149 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1150                     bool *is_64_bit)
1151 {
1152         int err;
1153         Elf *elf;
1154
1155         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1156         if (elf == NULL)
1157                 return -1;
1158
1159         if (is_64_bit)
1160                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1161
1162         err = elf_read_maps(elf, exe, mapfn, data);
1163
1164         elf_end(elf);
1165         return err;
1166 }
1167
1168 enum dso_type dso__type_fd(int fd)
1169 {
1170         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1171         GElf_Ehdr ehdr;
1172         Elf_Kind ek;
1173         Elf *elf;
1174
1175         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1176         if (elf == NULL)
1177                 goto out;
1178
1179         ek = elf_kind(elf);
1180         if (ek != ELF_K_ELF)
1181                 goto out_end;
1182
1183         if (gelf_getclass(elf) == ELFCLASS64) {
1184                 dso_type = DSO__TYPE_64BIT;
1185                 goto out_end;
1186         }
1187
1188         if (gelf_getehdr(elf, &ehdr) == NULL)
1189                 goto out_end;
1190
1191         if (ehdr.e_machine == EM_X86_64)
1192                 dso_type = DSO__TYPE_X32BIT;
1193         else
1194                 dso_type = DSO__TYPE_32BIT;
1195 out_end:
1196         elf_end(elf);
1197 out:
1198         return dso_type;
1199 }
1200
1201 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1202 {
1203         ssize_t r;
1204         size_t n;
1205         int err = -1;
1206         char *buf = malloc(page_size);
1207
1208         if (buf == NULL)
1209                 return -1;
1210
1211         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1212                 goto out;
1213
1214         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1215                 goto out;
1216
1217         while (len) {
1218                 n = page_size;
1219                 if (len < n)
1220                         n = len;
1221                 /* Use read because mmap won't work on proc files */
1222                 r = read(from, buf, n);
1223                 if (r < 0)
1224                         goto out;
1225                 if (!r)
1226                         break;
1227                 n = r;
1228                 r = write(to, buf, n);
1229                 if (r < 0)
1230                         goto out;
1231                 if ((size_t)r != n)
1232                         goto out;
1233                 len -= n;
1234         }
1235
1236         err = 0;
1237 out:
1238         free(buf);
1239         return err;
1240 }
1241
1242 struct kcore {
1243         int fd;
1244         int elfclass;
1245         Elf *elf;
1246         GElf_Ehdr ehdr;
1247 };
1248
1249 static int kcore__open(struct kcore *kcore, const char *filename)
1250 {
1251         GElf_Ehdr *ehdr;
1252
1253         kcore->fd = open(filename, O_RDONLY);
1254         if (kcore->fd == -1)
1255                 return -1;
1256
1257         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1258         if (!kcore->elf)
1259                 goto out_close;
1260
1261         kcore->elfclass = gelf_getclass(kcore->elf);
1262         if (kcore->elfclass == ELFCLASSNONE)
1263                 goto out_end;
1264
1265         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1266         if (!ehdr)
1267                 goto out_end;
1268
1269         return 0;
1270
1271 out_end:
1272         elf_end(kcore->elf);
1273 out_close:
1274         close(kcore->fd);
1275         return -1;
1276 }
1277
1278 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1279                        bool temp)
1280 {
1281         kcore->elfclass = elfclass;
1282
1283         if (temp)
1284                 kcore->fd = mkstemp(filename);
1285         else
1286                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1287         if (kcore->fd == -1)
1288                 return -1;
1289
1290         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1291         if (!kcore->elf)
1292                 goto out_close;
1293
1294         if (!gelf_newehdr(kcore->elf, elfclass))
1295                 goto out_end;
1296
1297         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1298
1299         return 0;
1300
1301 out_end:
1302         elf_end(kcore->elf);
1303 out_close:
1304         close(kcore->fd);
1305         unlink(filename);
1306         return -1;
1307 }
1308
1309 static void kcore__close(struct kcore *kcore)
1310 {
1311         elf_end(kcore->elf);
1312         close(kcore->fd);
1313 }
1314
1315 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1316 {
1317         GElf_Ehdr *ehdr = &to->ehdr;
1318         GElf_Ehdr *kehdr = &from->ehdr;
1319
1320         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1321         ehdr->e_type      = kehdr->e_type;
1322         ehdr->e_machine   = kehdr->e_machine;
1323         ehdr->e_version   = kehdr->e_version;
1324         ehdr->e_entry     = 0;
1325         ehdr->e_shoff     = 0;
1326         ehdr->e_flags     = kehdr->e_flags;
1327         ehdr->e_phnum     = count;
1328         ehdr->e_shentsize = 0;
1329         ehdr->e_shnum     = 0;
1330         ehdr->e_shstrndx  = 0;
1331
1332         if (from->elfclass == ELFCLASS32) {
1333                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1334                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1335                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1336         } else {
1337                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1338                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1339                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1340         }
1341
1342         if (!gelf_update_ehdr(to->elf, ehdr))
1343                 return -1;
1344
1345         if (!gelf_newphdr(to->elf, count))
1346                 return -1;
1347
1348         return 0;
1349 }
1350
1351 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1352                            u64 addr, u64 len)
1353 {
1354         GElf_Phdr phdr = {
1355                 .p_type         = PT_LOAD,
1356                 .p_flags        = PF_R | PF_W | PF_X,
1357                 .p_offset       = offset,
1358                 .p_vaddr        = addr,
1359                 .p_paddr        = 0,
1360                 .p_filesz       = len,
1361                 .p_memsz        = len,
1362                 .p_align        = page_size,
1363         };
1364
1365         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1366                 return -1;
1367
1368         return 0;
1369 }
1370
1371 static off_t kcore__write(struct kcore *kcore)
1372 {
1373         return elf_update(kcore->elf, ELF_C_WRITE);
1374 }
1375
1376 struct phdr_data {
1377         off_t offset;
1378         u64 addr;
1379         u64 len;
1380 };
1381
1382 struct kcore_copy_info {
1383         u64 stext;
1384         u64 etext;
1385         u64 first_symbol;
1386         u64 last_symbol;
1387         u64 first_module;
1388         u64 last_module_symbol;
1389         struct phdr_data kernel_map;
1390         struct phdr_data modules_map;
1391 };
1392
1393 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1394                                         u64 start)
1395 {
1396         struct kcore_copy_info *kci = arg;
1397
1398         if (!symbol_type__is_a(type, MAP__FUNCTION))
1399                 return 0;
1400
1401         if (strchr(name, '[')) {
1402                 if (start > kci->last_module_symbol)
1403                         kci->last_module_symbol = start;
1404                 return 0;
1405         }
1406
1407         if (!kci->first_symbol || start < kci->first_symbol)
1408                 kci->first_symbol = start;
1409
1410         if (!kci->last_symbol || start > kci->last_symbol)
1411                 kci->last_symbol = start;
1412
1413         if (!strcmp(name, "_stext")) {
1414                 kci->stext = start;
1415                 return 0;
1416         }
1417
1418         if (!strcmp(name, "_etext")) {
1419                 kci->etext = start;
1420                 return 0;
1421         }
1422
1423         return 0;
1424 }
1425
1426 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1427                                       const char *dir)
1428 {
1429         char kallsyms_filename[PATH_MAX];
1430
1431         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1432
1433         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1434                 return -1;
1435
1436         if (kallsyms__parse(kallsyms_filename, kci,
1437                             kcore_copy__process_kallsyms) < 0)
1438                 return -1;
1439
1440         return 0;
1441 }
1442
1443 static int kcore_copy__process_modules(void *arg,
1444                                        const char *name __maybe_unused,
1445                                        u64 start)
1446 {
1447         struct kcore_copy_info *kci = arg;
1448
1449         if (!kci->first_module || start < kci->first_module)
1450                 kci->first_module = start;
1451
1452         return 0;
1453 }
1454
1455 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1456                                      const char *dir)
1457 {
1458         char modules_filename[PATH_MAX];
1459
1460         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1461
1462         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1463                 return -1;
1464
1465         if (modules__parse(modules_filename, kci,
1466                            kcore_copy__process_modules) < 0)
1467                 return -1;
1468
1469         return 0;
1470 }
1471
1472 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1473                             u64 s, u64 e)
1474 {
1475         if (p->addr || s < start || s >= end)
1476                 return;
1477
1478         p->addr = s;
1479         p->offset = (s - start) + pgoff;
1480         p->len = e < end ? e - s : end - s;
1481 }
1482
1483 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1484 {
1485         struct kcore_copy_info *kci = data;
1486         u64 end = start + len;
1487
1488         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1489                         kci->etext);
1490
1491         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1492                         kci->last_module_symbol);
1493
1494         return 0;
1495 }
1496
1497 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1498 {
1499         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1500                 return -1;
1501
1502         return 0;
1503 }
1504
1505 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1506                                  Elf *elf)
1507 {
1508         if (kcore_copy__parse_kallsyms(kci, dir))
1509                 return -1;
1510
1511         if (kcore_copy__parse_modules(kci, dir))
1512                 return -1;
1513
1514         if (kci->stext)
1515                 kci->stext = round_down(kci->stext, page_size);
1516         else
1517                 kci->stext = round_down(kci->first_symbol, page_size);
1518
1519         if (kci->etext) {
1520                 kci->etext = round_up(kci->etext, page_size);
1521         } else if (kci->last_symbol) {
1522                 kci->etext = round_up(kci->last_symbol, page_size);
1523                 kci->etext += page_size;
1524         }
1525
1526         kci->first_module = round_down(kci->first_module, page_size);
1527
1528         if (kci->last_module_symbol) {
1529                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1530                                                    page_size);
1531                 kci->last_module_symbol += page_size;
1532         }
1533
1534         if (!kci->stext || !kci->etext)
1535                 return -1;
1536
1537         if (kci->first_module && !kci->last_module_symbol)
1538                 return -1;
1539
1540         return kcore_copy__read_maps(kci, elf);
1541 }
1542
1543 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1544                                  const char *name)
1545 {
1546         char from_filename[PATH_MAX];
1547         char to_filename[PATH_MAX];
1548
1549         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1550         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1551
1552         return copyfile_mode(from_filename, to_filename, 0400);
1553 }
1554
1555 static int kcore_copy__unlink(const char *dir, const char *name)
1556 {
1557         char filename[PATH_MAX];
1558
1559         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1560
1561         return unlink(filename);
1562 }
1563
1564 static int kcore_copy__compare_fds(int from, int to)
1565 {
1566         char *buf_from;
1567         char *buf_to;
1568         ssize_t ret;
1569         size_t len;
1570         int err = -1;
1571
1572         buf_from = malloc(page_size);
1573         buf_to = malloc(page_size);
1574         if (!buf_from || !buf_to)
1575                 goto out;
1576
1577         while (1) {
1578                 /* Use read because mmap won't work on proc files */
1579                 ret = read(from, buf_from, page_size);
1580                 if (ret < 0)
1581                         goto out;
1582
1583                 if (!ret)
1584                         break;
1585
1586                 len = ret;
1587
1588                 if (readn(to, buf_to, len) != (int)len)
1589                         goto out;
1590
1591                 if (memcmp(buf_from, buf_to, len))
1592                         goto out;
1593         }
1594
1595         err = 0;
1596 out:
1597         free(buf_to);
1598         free(buf_from);
1599         return err;
1600 }
1601
1602 static int kcore_copy__compare_files(const char *from_filename,
1603                                      const char *to_filename)
1604 {
1605         int from, to, err = -1;
1606
1607         from = open(from_filename, O_RDONLY);
1608         if (from < 0)
1609                 return -1;
1610
1611         to = open(to_filename, O_RDONLY);
1612         if (to < 0)
1613                 goto out_close_from;
1614
1615         err = kcore_copy__compare_fds(from, to);
1616
1617         close(to);
1618 out_close_from:
1619         close(from);
1620         return err;
1621 }
1622
1623 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1624                                     const char *name)
1625 {
1626         char from_filename[PATH_MAX];
1627         char to_filename[PATH_MAX];
1628
1629         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1630         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1631
1632         return kcore_copy__compare_files(from_filename, to_filename);
1633 }
1634
1635 /**
1636  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1637  * @from_dir: from directory
1638  * @to_dir: to directory
1639  *
1640  * This function copies kallsyms, modules and kcore files from one directory to
1641  * another.  kallsyms and modules are copied entirely.  Only code segments are
1642  * copied from kcore.  It is assumed that two segments suffice: one for the
1643  * kernel proper and one for all the modules.  The code segments are determined
1644  * from kallsyms and modules files.  The kernel map starts at _stext or the
1645  * lowest function symbol, and ends at _etext or the highest function symbol.
1646  * The module map starts at the lowest module address and ends at the highest
1647  * module symbol.  Start addresses are rounded down to the nearest page.  End
1648  * addresses are rounded up to the nearest page.  An extra page is added to the
1649  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1650  * symbol too.  Because it contains only code sections, the resulting kcore is
1651  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1652  * is not the same for the kernel map and the modules map.  That happens because
1653  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1654  * kallsyms and modules files are compared with their copies to check that
1655  * modules have not been loaded or unloaded while the copies were taking place.
1656  *
1657  * Return: %0 on success, %-1 on failure.
1658  */
1659 int kcore_copy(const char *from_dir, const char *to_dir)
1660 {
1661         struct kcore kcore;
1662         struct kcore extract;
1663         size_t count = 2;
1664         int idx = 0, err = -1;
1665         off_t offset = page_size, sz, modules_offset = 0;
1666         struct kcore_copy_info kci = { .stext = 0, };
1667         char kcore_filename[PATH_MAX];
1668         char extract_filename[PATH_MAX];
1669
1670         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1671                 return -1;
1672
1673         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1674                 goto out_unlink_kallsyms;
1675
1676         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1677         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1678
1679         if (kcore__open(&kcore, kcore_filename))
1680                 goto out_unlink_modules;
1681
1682         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1683                 goto out_kcore_close;
1684
1685         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1686                 goto out_kcore_close;
1687
1688         if (!kci.modules_map.addr)
1689                 count -= 1;
1690
1691         if (kcore__copy_hdr(&kcore, &extract, count))
1692                 goto out_extract_close;
1693
1694         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1695                             kci.kernel_map.len))
1696                 goto out_extract_close;
1697
1698         if (kci.modules_map.addr) {
1699                 modules_offset = offset + kci.kernel_map.len;
1700                 if (kcore__add_phdr(&extract, idx, modules_offset,
1701                                     kci.modules_map.addr, kci.modules_map.len))
1702                         goto out_extract_close;
1703         }
1704
1705         sz = kcore__write(&extract);
1706         if (sz < 0 || sz > offset)
1707                 goto out_extract_close;
1708
1709         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1710                        kci.kernel_map.len))
1711                 goto out_extract_close;
1712
1713         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1714                                          extract.fd, modules_offset,
1715                                          kci.modules_map.len))
1716                 goto out_extract_close;
1717
1718         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1719                 goto out_extract_close;
1720
1721         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1722                 goto out_extract_close;
1723
1724         err = 0;
1725
1726 out_extract_close:
1727         kcore__close(&extract);
1728         if (err)
1729                 unlink(extract_filename);
1730 out_kcore_close:
1731         kcore__close(&kcore);
1732 out_unlink_modules:
1733         if (err)
1734                 kcore_copy__unlink(to_dir, "modules");
1735 out_unlink_kallsyms:
1736         if (err)
1737                 kcore_copy__unlink(to_dir, "kallsyms");
1738
1739         return err;
1740 }
1741
1742 int kcore_extract__create(struct kcore_extract *kce)
1743 {
1744         struct kcore kcore;
1745         struct kcore extract;
1746         size_t count = 1;
1747         int idx = 0, err = -1;
1748         off_t offset = page_size, sz;
1749
1750         if (kcore__open(&kcore, kce->kcore_filename))
1751                 return -1;
1752
1753         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1754         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1755                 goto out_kcore_close;
1756
1757         if (kcore__copy_hdr(&kcore, &extract, count))
1758                 goto out_extract_close;
1759
1760         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1761                 goto out_extract_close;
1762
1763         sz = kcore__write(&extract);
1764         if (sz < 0 || sz > offset)
1765                 goto out_extract_close;
1766
1767         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1768                 goto out_extract_close;
1769
1770         err = 0;
1771
1772 out_extract_close:
1773         kcore__close(&extract);
1774         if (err)
1775                 unlink(kce->extract_filename);
1776 out_kcore_close:
1777         kcore__close(&kcore);
1778
1779         return err;
1780 }
1781
1782 void kcore_extract__delete(struct kcore_extract *kce)
1783 {
1784         unlink(kce->extract_filename);
1785 }
1786
1787 void symbol__elf_init(void)
1788 {
1789         elf_version(EV_CURRENT);
1790 }