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 "demangle-java.h"
  10 #include "machine.h"
  11 #include "vdso.h"
  12 #include <symbol/kallsyms.h>
  13 #include "debug.h"
  14
  15 #ifndef EM_AARCH64
  16 #define EM_AARCH64      183  /* ARM 64 bit */
  17 #endif
  18
  19
  20 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  21 extern char *cplus_demangle(const char *, int);
  22
  23 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  24 {
  25         return cplus_demangle(c, i);
  26 }
  27 #else
  28 #ifdef NO_DEMANGLE
  29 static inline char *bfd_demangle(void __maybe_unused *v,
  30                                  const char __maybe_unused *c,
  31                                  int __maybe_unused i)
  32 {
  33         return NULL;
  34 }
  35 #else
  36 #define PACKAGE 'perf'
  37 #include <bfd.h>
  38 #endif
  39 #endif
  40
  41 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  42 static int elf_getphdrnum(Elf *elf, size_t *dst)
  43 {
  44         GElf_Ehdr gehdr;
  45         GElf_Ehdr *ehdr;
  46
  47         ehdr = gelf_getehdr(elf, &gehdr);
  48         if (!ehdr)
  49                 return -1;
  50
  51         *dst = ehdr->e_phnum;
  52
  53         return 0;
  54 }
  55 #endif
  56
  57 #ifndef NT_GNU_BUILD_ID
  58 #define NT_GNU_BUILD_ID 3
  59 #endif
  60
  61 /**
  62  * elf_symtab__for_each_symbol - iterate thru all the symbols
  63  *
  64  * @syms: struct elf_symtab instance to iterate
  65  * @idx: uint32_t idx
  66  * @sym: GElf_Sym iterator
  67  */
  68 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  69         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  70              idx < nr_syms; \
  71              idx++, gelf_getsym(syms, idx, &sym))
  72
  73 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  74 {
  75         return GELF_ST_TYPE(sym->st_info);
  76 }
  77
  78 #ifndef STT_GNU_IFUNC
  79 #define STT_GNU_IFUNC 10
  80 #endif
  81
  82 static inline int elf_sym__is_function(const GElf_Sym *sym)
  83 {
  84         return (elf_sym__type(sym) == STT_FUNC ||
  85                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  86                sym->st_name != 0 &&
  87                sym->st_shndx != SHN_UNDEF;
  88 }
  89
  90 static inline bool elf_sym__is_object(const GElf_Sym *sym)
  91 {
  92         return elf_sym__type(sym) == STT_OBJECT &&
  93                 sym->st_name != 0 &&
  94                 sym->st_shndx != SHN_UNDEF;
  95 }
  96
  97 static inline int elf_sym__is_label(const GElf_Sym *sym)
  98 {
  99         return elf_sym__type(sym) == STT_NOTYPE &&
 100                 sym->st_name != 0 &&
 101                 sym->st_shndx != SHN_UNDEF &&
 102                 sym->st_shndx != SHN_ABS;
 103 }
 104
 105 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
 106 {
 107         switch (type) {
 108         case MAP__FUNCTION:
 109                 return elf_sym__is_function(sym);
 110         case MAP__VARIABLE:
 111                 return elf_sym__is_object(sym);
 112         default:
 113                 return false;
 114         }
 115 }
 116
 117 static inline const char *elf_sym__name(const GElf_Sym *sym,
 118                                         const Elf_Data *symstrs)
 119 {
 120         return symstrs->d_buf + sym->st_name;
 121 }
 122
 123 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 124                                         const Elf_Data *secstrs)
 125 {
 126         return secstrs->d_buf + shdr->sh_name;
 127 }
 128
 129 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 130                                         const Elf_Data *secstrs)
 131 {
 132         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 133 }
 134
 135 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 136                                     const Elf_Data *secstrs)
 137 {
 138         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 139 }
 140
 141 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 142                           enum map_type type)
 143 {
 144         switch (type) {
 145         case MAP__FUNCTION:
 146                 return elf_sec__is_text(shdr, secstrs);
 147         case MAP__VARIABLE:
 148                 return elf_sec__is_data(shdr, secstrs);
 149         default:
 150                 return false;
 151         }
 152 }
 153
 154 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 155 {
 156         Elf_Scn *sec = NULL;
 157         GElf_Shdr shdr;
 158         size_t cnt = 1;
 159
 160         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 161                 gelf_getshdr(sec, &shdr);
 162
 163                 if ((addr >= shdr.sh_addr) &&
 164                     (addr < (shdr.sh_addr + shdr.sh_size)))
 165                         return cnt;
 166
 167                 ++cnt;
 168         }
 169
 170         return -1;
 171 }
 172
 173 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 174                              GElf_Shdr *shp, const char *name, size_t *idx)
 175 {
 176         Elf_Scn *sec = NULL;
 177         size_t cnt = 1;
 178
 179         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 180         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 181                 return NULL;
 182
 183         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 184                 char *str;
 185
 186                 gelf_getshdr(sec, shp);
 187                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 188                 if (str && !strcmp(name, str)) {
 189                         if (idx)
 190                                 *idx = cnt;
 191                         return sec;
 192                 }
 193                 ++cnt;
 194         }
 195
 196         return NULL;
 197 }
 198
 199 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 200         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 201              idx < nr_entries; \
 202              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 203
 204 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 205         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 206              idx < nr_entries; \
 207              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 208
 209 /*
 210  * We need to check if we have a .dynsym, so that we can handle the
 211  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 212  * .dynsym or .symtab).
 213  * And always look at the original dso, not at debuginfo packages, that
 214  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 215  */
 216 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map,
 217                                 symbol_filter_t filter)
 218 {
 219         uint32_t nr_rel_entries, idx;
 220         GElf_Sym sym;
 221         u64 plt_offset;
 222         GElf_Shdr shdr_plt;
 223         struct symbol *f;
 224         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 225         Elf_Data *reldata, *syms, *symstrs;
 226         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 227         size_t dynsym_idx;
 228         GElf_Ehdr ehdr;
 229         char sympltname[1024];
 230         Elf *elf;
 231         int nr = 0, symidx, err = 0;
 232
 233         if (!ss->dynsym)
 234                 return 0;
 235
 236         elf = ss->elf;
 237         ehdr = ss->ehdr;
 238
 239         scn_dynsym = ss->dynsym;
 240         shdr_dynsym = ss->dynshdr;
 241         dynsym_idx = ss->dynsym_idx;
 242
 243         if (scn_dynsym == NULL)
 244                 goto out_elf_end;
 245
 246         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 247                                           ".rela.plt", NULL);
 248         if (scn_plt_rel == NULL) {
 249                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 250                                                   ".rel.plt", NULL);
 251                 if (scn_plt_rel == NULL)
 252                         goto out_elf_end;
 253         }
 254
 255         err = -1;
 256
 257         if (shdr_rel_plt.sh_link != dynsym_idx)
 258                 goto out_elf_end;
 259
 260         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 261                 goto out_elf_end;
 262
 263         /*
 264          * Fetch the relocation section to find the idxes to the GOT
 265          * and the symbols in the .dynsym they refer to.
 266          */
 267         reldata = elf_getdata(scn_plt_rel, NULL);
 268         if (reldata == NULL)
 269                 goto out_elf_end;
 270
 271         syms = elf_getdata(scn_dynsym, NULL);
 272         if (syms == NULL)
 273                 goto out_elf_end;
 274
 275         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 276         if (scn_symstrs == NULL)
 277                 goto out_elf_end;
 278
 279         symstrs = elf_getdata(scn_symstrs, NULL);
 280         if (symstrs == NULL)
 281                 goto out_elf_end;
 282
 283         if (symstrs->d_size == 0)
 284                 goto out_elf_end;
 285
 286         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 287         plt_offset = shdr_plt.sh_offset;
 288
 289         if (shdr_rel_plt.sh_type == SHT_RELA) {
 290                 GElf_Rela pos_mem, *pos;
 291
 292                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 293                                            nr_rel_entries) {
 294                         symidx = GELF_R_SYM(pos->r_info);
 295                         plt_offset += shdr_plt.sh_entsize;
 296                         gelf_getsym(syms, symidx, &sym);
 297                         snprintf(sympltname, sizeof(sympltname),
 298                                  "%s@plt", elf_sym__name(&sym, symstrs));
 299
 300                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 301                                         STB_GLOBAL, sympltname);
 302                         if (!f)
 303                                 goto out_elf_end;
 304
 305                         if (filter && filter(map, f))
 306                                 symbol__delete(f);
 307                         else {
 308                                 symbols__insert(&dso->symbols[map->type], f);
 309                                 ++nr;
 310                         }
 311                 }
 312         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 313                 GElf_Rel pos_mem, *pos;
 314                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 315                                           nr_rel_entries) {
 316                         symidx = GELF_R_SYM(pos->r_info);
 317                         plt_offset += shdr_plt.sh_entsize;
 318                         gelf_getsym(syms, symidx, &sym);
 319                         snprintf(sympltname, sizeof(sympltname),
 320                                  "%s@plt", elf_sym__name(&sym, symstrs));
 321
 322                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 323                                         STB_GLOBAL, sympltname);
 324                         if (!f)
 325                                 goto out_elf_end;
 326
 327                         if (filter && filter(map, f))
 328                                 symbol__delete(f);
 329                         else {
 330                                 symbols__insert(&dso->symbols[map->type], f);
 331                                 ++nr;
 332                         }
 333                 }
 334         }
 335
 336         err = 0;
 337 out_elf_end:
 338         if (err == 0)
 339                 return nr;
 340         pr_debug("%s: problems reading %s PLT info.\n",
 341                  __func__, dso->long_name);
 342         return 0;
 343 }
 344
 345 /*
 346  * Align offset to 4 bytes as needed for note name and descriptor data.
 347  */
 348 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 349
 350 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 351 {
 352         int err = -1;
 353         GElf_Ehdr ehdr;
 354         GElf_Shdr shdr;
 355         Elf_Data *data;
 356         Elf_Scn *sec;
 357         Elf_Kind ek;
 358         void *ptr;
 359
 360         if (size < BUILD_ID_SIZE)
 361                 goto out;
 362
 363         ek = elf_kind(elf);
 364         if (ek != ELF_K_ELF)
 365                 goto out;
 366
 367         if (gelf_getehdr(elf, &ehdr) == NULL) {
 368                 pr_err("%s: cannot get elf header.\n", __func__);
 369                 goto out;
 370         }
 371
 372         /*
 373          * Check following sections for notes:
 374          *   '.note.gnu.build-id'
 375          *   '.notes'
 376          *   '.note' (VDSO specific)
 377          */
 378         do {
 379                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 380                                           ".note.gnu.build-id", NULL);
 381                 if (sec)
 382                         break;
 383
 384                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 385                                           ".notes", NULL);
 386                 if (sec)
 387                         break;
 388
 389                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 390                                           ".note", NULL);
 391                 if (sec)
 392                         break;
 393
 394                 return err;
 395
 396         } while (0);
 397
 398         data = elf_getdata(sec, NULL);
 399         if (data == NULL)
 400                 goto out;
 401
 402         ptr = data->d_buf;
 403         while (ptr < (data->d_buf + data->d_size)) {
 404                 GElf_Nhdr *nhdr = ptr;
 405                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 406                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 407                 const char *name;
 408
 409                 ptr += sizeof(*nhdr);
 410                 name = ptr;
 411                 ptr += namesz;
 412                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 413                     nhdr->n_namesz == sizeof("GNU")) {
 414                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 415                                 size_t sz = min(size, descsz);
 416                                 memcpy(bf, ptr, sz);
 417                                 memset(bf + sz, 0, size - sz);
 418                                 err = descsz;
 419                                 break;
 420                         }
 421                 }
 422                 ptr += descsz;
 423         }
 424
 425 out:
 426         return err;
 427 }
 428
 429 int filename__read_build_id(const char *filename, void *bf, size_t size)
 430 {
 431         int fd, err = -1;
 432         Elf *elf;
 433
 434         if (size < BUILD_ID_SIZE)
 435                 goto out;
 436
 437         fd = open(filename, O_RDONLY);
 438         if (fd < 0)
 439                 goto out;
 440
 441         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 442         if (elf == NULL) {
 443                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 444                 goto out_close;
 445         }
 446
 447         err = elf_read_build_id(elf, bf, size);
 448
 449         elf_end(elf);
 450 out_close:
 451         close(fd);
 452 out:
 453         return err;
 454 }
 455
 456 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 457 {
 458         int fd, err = -1;
 459
 460         if (size < BUILD_ID_SIZE)
 461                 goto out;
 462
 463         fd = open(filename, O_RDONLY);
 464         if (fd < 0)
 465                 goto out;
 466
 467         while (1) {
 468                 char bf[BUFSIZ];
 469                 GElf_Nhdr nhdr;
 470                 size_t namesz, descsz;
 471
 472                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 473                         break;
 474
 475                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 476                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 477                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 478                     nhdr.n_namesz == sizeof("GNU")) {
 479                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 480                                 break;
 481                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 482                                 size_t sz = min(descsz, size);
 483                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 484                                         memset(build_id + sz, 0, size - sz);
 485                                         err = 0;
 486                                         break;
 487                                 }
 488                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 489                                 break;
 490                 } else {
 491                         int n = namesz + descsz;
 492                         if (read(fd, bf, n) != n)
 493                                 break;
 494                 }
 495         }
 496         close(fd);
 497 out:
 498         return err;
 499 }
 500
 501 int filename__read_debuglink(const char *filename, char *debuglink,
 502                              size_t size)
 503 {
 504         int fd, err = -1;
 505         Elf *elf;
 506         GElf_Ehdr ehdr;
 507         GElf_Shdr shdr;
 508         Elf_Data *data;
 509         Elf_Scn *sec;
 510         Elf_Kind ek;
 511
 512         fd = open(filename, O_RDONLY);
 513         if (fd < 0)
 514                 goto out;
 515
 516         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 517         if (elf == NULL) {
 518                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 519                 goto out_close;
 520         }
 521
 522         ek = elf_kind(elf);
 523         if (ek != ELF_K_ELF)
 524                 goto out_elf_end;
 525
 526         if (gelf_getehdr(elf, &ehdr) == NULL) {
 527                 pr_err("%s: cannot get elf header.\n", __func__);
 528                 goto out_elf_end;
 529         }
 530
 531         sec = elf_section_by_name(elf, &ehdr, &shdr,
 532                                   ".gnu_debuglink", NULL);
 533         if (sec == NULL)
 534                 goto out_elf_end;
 535
 536         data = elf_getdata(sec, NULL);
 537         if (data == NULL)
 538                 goto out_elf_end;
 539
 540         /* the start of this section is a zero-terminated string */
 541         strncpy(debuglink, data->d_buf, size);
 542
 543         err = 0;
 544
 545 out_elf_end:
 546         elf_end(elf);
 547 out_close:
 548         close(fd);
 549 out:
 550         return err;
 551 }
 552
 553 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 554 {
 555         static unsigned int const endian = 1;
 556
 557         dso->needs_swap = DSO_SWAP__NO;
 558
 559         switch (eidata) {
 560         case ELFDATA2LSB:
 561                 /* We are big endian, DSO is little endian. */
 562                 if (*(unsigned char const *)&endian != 1)
 563                         dso->needs_swap = DSO_SWAP__YES;
 564                 break;
 565
 566         case ELFDATA2MSB:
 567                 /* We are little endian, DSO is big endian. */
 568                 if (*(unsigned char const *)&endian != 0)
 569                         dso->needs_swap = DSO_SWAP__YES;
 570                 break;
 571
 572         default:
 573                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 574                 return -EINVAL;
 575         }
 576
 577         return 0;
 578 }
 579
 580 static int decompress_kmodule(struct dso *dso, const char *name,
 581                               enum dso_binary_type type)
 582 {
 583         int fd = -1;
 584         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 585         struct kmod_path m;
 586
 587         if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
 588             type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
 589             type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
 590                 return -1;
 591
 592         if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
 593                 name = dso->long_name;
 594
 595         if (kmod_path__parse_ext(&m, name) || !m.comp)
 596                 return -1;
 597
 598         fd = mkstemp(tmpbuf);
 599         if (fd < 0) {
 600                 dso->load_errno = errno;
 601                 goto out;
 602         }
 603
 604         if (!decompress_to_file(m.ext, name, fd)) {
 605                 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
 606                 close(fd);
 607                 fd = -1;
 608         }
 609
 610         unlink(tmpbuf);
 611
 612 out:
 613         free(m.ext);
 614         return fd;
 615 }
 616
 617 bool symsrc__possibly_runtime(struct symsrc *ss)
 618 {
 619         return ss->dynsym || ss->opdsec;
 620 }
 621
 622 bool symsrc__has_symtab(struct symsrc *ss)
 623 {
 624         return ss->symtab != NULL;
 625 }
 626
 627 void symsrc__destroy(struct symsrc *ss)
 628 {
 629         zfree(&ss->name);
 630         elf_end(ss->elf);
 631         close(ss->fd);
 632 }
 633
 634 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 635 {
 636         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 637 }
 638
 639 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 640                  enum dso_binary_type type)
 641 {
 642         int err = -1;
 643         GElf_Ehdr ehdr;
 644         Elf *elf;
 645         int fd;
 646
 647         if (dso__needs_decompress(dso)) {
 648                 fd = decompress_kmodule(dso, name, type);
 649                 if (fd < 0)
 650                         return -1;
 651         } else {
 652                 fd = open(name, O_RDONLY);
 653                 if (fd < 0) {
 654                         dso->load_errno = errno;
 655                         return -1;
 656                 }
 657         }
 658
 659         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 660         if (elf == NULL) {
 661                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 662                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 663                 goto out_close;
 664         }
 665
 666         if (gelf_getehdr(elf, &ehdr) == NULL) {
 667                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 668                 pr_debug("%s: cannot get elf header.\n", __func__);
 669                 goto out_elf_end;
 670         }
 671
 672         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 673                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 674                 goto out_elf_end;
 675         }
 676
 677         /* Always reject images with a mismatched build-id: */
 678         if (dso->has_build_id) {
 679                 u8 build_id[BUILD_ID_SIZE];
 680
 681                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 682                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 683                         goto out_elf_end;
 684                 }
 685
 686                 if (!dso__build_id_equal(dso, build_id)) {
 687                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 688                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 689                         goto out_elf_end;
 690                 }
 691         }
 692
 693         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 694
 695         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 696                         NULL);
 697         if (ss->symshdr.sh_type != SHT_SYMTAB)
 698                 ss->symtab = NULL;
 699
 700         ss->dynsym_idx = 0;
 701         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 702                         &ss->dynsym_idx);
 703         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 704                 ss->dynsym = NULL;
 705
 706         ss->opdidx = 0;
 707         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 708                         &ss->opdidx);
 709         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 710                 ss->opdsec = NULL;
 711
 712         if (dso->kernel == DSO_TYPE_USER) {
 713                 GElf_Shdr shdr;
 714                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 715                                 ehdr.e_type == ET_REL ||
 716                                 dso__is_vdso(dso) ||
 717                                 elf_section_by_name(elf, &ehdr, &shdr,
 718                                                      ".gnu.prelink_undo",
 719                                                      NULL) != NULL);
 720         } else {
 721                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 722         }
 723
 724         ss->name   = strdup(name);
 725         if (!ss->name) {
 726                 dso->load_errno = errno;
 727                 goto out_elf_end;
 728         }
 729
 730         ss->elf    = elf;
 731         ss->fd     = fd;
 732         ss->ehdr   = ehdr;
 733         ss->type   = type;
 734
 735         return 0;
 736
 737 out_elf_end:
 738         elf_end(elf);
 739 out_close:
 740         close(fd);
 741         return err;
 742 }
 743
 744 /**
 745  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 746  * @kmap: kernel maps and relocation reference symbol
 747  *
 748  * This function returns %true if we are dealing with the kernel maps and the
 749  * relocation reference symbol has not yet been found.  Otherwise %false is
 750  * returned.
 751  */
 752 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 753 {
 754         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 755                !kmap->ref_reloc_sym->unrelocated_addr;
 756 }
 757
 758 /**
 759  * ref_reloc - kernel relocation offset.
 760  * @kmap: kernel maps and relocation reference symbol
 761  *
 762  * This function returns the offset of kernel addresses as determined by using
 763  * the relocation reference symbol i.e. if the kernel has not been relocated
 764  * then the return value is zero.
 765  */
 766 static u64 ref_reloc(struct kmap *kmap)
 767 {
 768         if (kmap && kmap->ref_reloc_sym &&
 769             kmap->ref_reloc_sym->unrelocated_addr)
 770                 return kmap->ref_reloc_sym->addr -
 771                        kmap->ref_reloc_sym->unrelocated_addr;
 772         return 0;
 773 }
 774
 775 static bool want_demangle(bool is_kernel_sym)
 776 {
 777         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 778 }
 779
 780 void __weak arch__elf_sym_adjust(GElf_Sym *sym __maybe_unused) { }
 781
 782 int dso__load_sym(struct dso *dso, struct map *map,
 783                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 784                   symbol_filter_t filter, int kmodule)
 785 {
 786         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 787         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 788         struct map *curr_map = map;
 789         struct dso *curr_dso = dso;
 790         Elf_Data *symstrs, *secstrs;
 791         uint32_t nr_syms;
 792         int err = -1;
 793         uint32_t idx;
 794         GElf_Ehdr ehdr;
 795         GElf_Shdr shdr;
 796         GElf_Shdr tshdr;
 797         Elf_Data *syms, *opddata = NULL;
 798         GElf_Sym sym;
 799         Elf_Scn *sec, *sec_strndx;
 800         Elf *elf;
 801         int nr = 0;
 802         bool remap_kernel = false, adjust_kernel_syms = false;
 803
 804         if (kmap && !kmaps)
 805                 return -1;
 806
 807         dso->symtab_type = syms_ss->type;
 808         dso->is_64_bit = syms_ss->is_64_bit;
 809         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 810
 811         /*
 812          * Modules may already have symbols from kallsyms, but those symbols
 813          * have the wrong values for the dso maps, so remove them.
 814          */
 815         if (kmodule && syms_ss->symtab)
 816                 symbols__delete(&dso->symbols[map->type]);
 817
 818         if (!syms_ss->symtab) {
 819                 /*
 820                  * If the vmlinux is stripped, fail so we will fall back
 821                  * to using kallsyms. The vmlinux runtime symbols aren't
 822                  * of much use.
 823                  */
 824                 if (dso->kernel)
 825                         goto out_elf_end;
 826
 827                 syms_ss->symtab  = syms_ss->dynsym;
 828                 syms_ss->symshdr = syms_ss->dynshdr;
 829         }
 830
 831         elf = syms_ss->elf;
 832         ehdr = syms_ss->ehdr;
 833         sec = syms_ss->symtab;
 834         shdr = syms_ss->symshdr;
 835
 836         if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
 837                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 838
 839         if (runtime_ss->opdsec)
 840                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 841
 842         syms = elf_getdata(sec, NULL);
 843         if (syms == NULL)
 844                 goto out_elf_end;
 845
 846         sec = elf_getscn(elf, shdr.sh_link);
 847         if (sec == NULL)
 848                 goto out_elf_end;
 849
 850         symstrs = elf_getdata(sec, NULL);
 851         if (symstrs == NULL)
 852                 goto out_elf_end;
 853
 854         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 855         if (sec_strndx == NULL)
 856                 goto out_elf_end;
 857
 858         secstrs = elf_getdata(sec_strndx, NULL);
 859         if (secstrs == NULL)
 860                 goto out_elf_end;
 861
 862         nr_syms = shdr.sh_size / shdr.sh_entsize;
 863
 864         memset(&sym, 0, sizeof(sym));
 865
 866         /*
 867          * The kernel relocation symbol is needed in advance in order to adjust
 868          * kernel maps correctly.
 869          */
 870         if (ref_reloc_sym_not_found(kmap)) {
 871                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 872                         const char *elf_name = elf_sym__name(&sym, symstrs);
 873
 874                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 875                                 continue;
 876                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 877                         map->reloc = kmap->ref_reloc_sym->addr -
 878                                      kmap->ref_reloc_sym->unrelocated_addr;
 879                         break;
 880                 }
 881         }
 882
 883         /*
 884          * Handle any relocation of vdso necessary because older kernels
 885          * attempted to prelink vdso to its virtual address.
 886          */
 887         if (dso__is_vdso(dso))
 888                 map->reloc = map->start - dso->text_offset;
 889
 890         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 891         /*
 892          * Initial kernel and module mappings do not map to the dso.  For
 893          * function mappings, flag the fixups.
 894          */
 895         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 896                 remap_kernel = true;
 897                 adjust_kernel_syms = dso->adjust_symbols;
 898         }
 899         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 900                 struct symbol *f;
 901                 const char *elf_name = elf_sym__name(&sym, symstrs);
 902                 char *demangled = NULL;
 903                 int is_label = elf_sym__is_label(&sym);
 904                 const char *section_name;
 905                 bool used_opd = false;
 906
 907                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 908                         continue;
 909
 910                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 911                  * don't identify functions, so will confuse the profile
 912                  * output: */
 913                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 914                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 915                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 916                                 continue;
 917                 }
 918
 919                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 920                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 921                         u64 *opd = opddata->d_buf + offset;
 922                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 923                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 924                                         sym.st_value);
 925                         used_opd = true;
 926                 }
 927                 /*
 928                  * When loading symbols in a data mapping, ABS symbols (which
 929                  * has a value of SHN_ABS in its st_shndx) failed at
 930                  * elf_getscn().  And it marks the loading as a failure so
 931                  * already loaded symbols cannot be fixed up.
 932                  *
 933                  * I'm not sure what should be done. Just ignore them for now.
 934                  * - Namhyung Kim
 935                  */
 936                 if (sym.st_shndx == SHN_ABS)
 937                         continue;
 938
 939                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 940                 if (!sec)
 941                         goto out_elf_end;
 942
 943                 gelf_getshdr(sec, &shdr);
 944
 945                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 946                         continue;
 947
 948                 section_name = elf_sec__name(&shdr, secstrs);
 949
 950                 /* On ARM, symbols for thumb functions have 1 added to
 951                  * the symbol address as a flag - remove it */
 952                 if ((ehdr.e_machine == EM_ARM) &&
 953                     (map->type == MAP__FUNCTION) &&
 954                     (sym.st_value & 1))
 955                         --sym.st_value;
 956
 957                 arch__elf_sym_adjust(&sym);
 958
 959                 if (dso->kernel || kmodule) {
 960                         char dso_name[PATH_MAX];
 961
 962                         /* Adjust symbol to map to file offset */
 963                         if (adjust_kernel_syms)
 964                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 965
 966                         if (strcmp(section_name,
 967                                    (curr_dso->short_name +
 968                                     dso->short_name_len)) == 0)
 969                                 goto new_symbol;
 970
 971                         if (strcmp(section_name, ".text") == 0) {
 972                                 /*
 973                                  * The initial kernel mapping is based on
 974                                  * kallsyms and identity maps.  Overwrite it to
 975                                  * map to the kernel dso.
 976                                  */
 977                                 if (remap_kernel && dso->kernel) {
 978                                         remap_kernel = false;
 979                                         map->start = shdr.sh_addr +
 980                                                      ref_reloc(kmap);
 981                                         map->end = map->start + shdr.sh_size;
 982                                         map->pgoff = shdr.sh_offset;
 983                                         map->map_ip = map__map_ip;
 984                                         map->unmap_ip = map__unmap_ip;
 985                                         /* Ensure maps are correctly ordered */
 986                                         if (kmaps) {
 987                                                 map__get(map);
 988                                                 map_groups__remove(kmaps, map);
 989                                                 map_groups__insert(kmaps, map);
 990                                                 map__put(map);
 991                                         }
 992                                 }
 993
 994                                 /*
 995                                  * The initial module mapping is based on
 996                                  * /proc/modules mapped to offset zero.
 997                                  * Overwrite it to map to the module dso.
 998                                  */
 999                                 if (remap_kernel && kmodule) {
1000                                         remap_kernel = false;
1001                                         map->pgoff = shdr.sh_offset;
1002                                 }
1003
1004                                 curr_map = map;
1005                                 curr_dso = dso;
1006                                 goto new_symbol;
1007                         }
1008
1009                         if (!kmap)
1010                                 goto new_symbol;
1011
1012                         snprintf(dso_name, sizeof(dso_name),
1013                                  "%s%s", dso->short_name, section_name);
1014
1015                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1016                         if (curr_map == NULL) {
1017                                 u64 start = sym.st_value;
1018
1019                                 if (kmodule)
1020                                         start += map->start + shdr.sh_offset;
1021
1022                                 curr_dso = dso__new(dso_name);
1023                                 if (curr_dso == NULL)
1024                                         goto out_elf_end;
1025                                 curr_dso->kernel = dso->kernel;
1026                                 curr_dso->long_name = dso->long_name;
1027                                 curr_dso->long_name_len = dso->long_name_len;
1028                                 curr_map = map__new2(start, curr_dso,
1029                                                      map->type);
1030                                 dso__put(curr_dso);
1031                                 if (curr_map == NULL) {
1032                                         goto out_elf_end;
1033                                 }
1034                                 if (adjust_kernel_syms) {
1035                                         curr_map->start = shdr.sh_addr +
1036                                                           ref_reloc(kmap);
1037                                         curr_map->end = curr_map->start +
1038                                                         shdr.sh_size;
1039                                         curr_map->pgoff = shdr.sh_offset;
1040                                 } else {
1041                                         curr_map->map_ip = identity__map_ip;
1042                                         curr_map->unmap_ip = identity__map_ip;
1043                                 }
1044                                 curr_dso->symtab_type = dso->symtab_type;
1045                                 map_groups__insert(kmaps, curr_map);
1046                                 /*
1047                                  * Add it before we drop the referece to curr_map,
1048                                  * i.e. while we still are sure to have a reference
1049                                  * to this DSO via curr_map->dso.
1050                                  */
1051                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1052                                 /* kmaps already got it */
1053                                 map__put(curr_map);
1054                                 dso__set_loaded(curr_dso, map->type);
1055                         } else
1056                                 curr_dso = curr_map->dso;
1057
1058                         goto new_symbol;
1059                 }
1060
1061                 if ((used_opd && runtime_ss->adjust_symbols)
1062                                 || (!used_opd && syms_ss->adjust_symbols)) {
1063                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1064                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1065                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1066                                   (u64)shdr.sh_offset);
1067                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1068                 }
1069 new_symbol:
1070                 /*
1071                  * We need to figure out if the object was created from C++ sources
1072                  * DWARF DW_compile_unit has this, but we don't always have access
1073                  * to it...
1074                  */
1075                 if (want_demangle(dso->kernel || kmodule)) {
1076                         int demangle_flags = DMGL_NO_OPTS;
1077                         if (verbose)
1078                                 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1079
1080                         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1081                         if (demangled == NULL)
1082                                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
1083                         if (demangled != NULL)
1084                                 elf_name = demangled;
1085                 }
1086                 f = symbol__new(sym.st_value, sym.st_size,
1087                                 GELF_ST_BIND(sym.st_info), elf_name);
1088                 free(demangled);
1089                 if (!f)
1090                         goto out_elf_end;
1091
1092                 if (filter && filter(curr_map, f))
1093                         symbol__delete(f);
1094                 else {
1095                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
1096                         nr++;
1097                 }
1098         }
1099
1100         /*
1101          * For misannotated, zeroed, ASM function sizes.
1102          */
1103         if (nr > 0) {
1104                 if (!symbol_conf.allow_aliases)
1105                         symbols__fixup_duplicate(&dso->symbols[map->type]);
1106                 symbols__fixup_end(&dso->symbols[map->type]);
1107                 if (kmap) {
1108                         /*
1109                          * We need to fixup this here too because we create new
1110                          * maps here, for things like vsyscall sections.
1111                          */
1112                         __map_groups__fixup_end(kmaps, map->type);
1113                 }
1114         }
1115         err = nr;
1116 out_elf_end:
1117         return err;
1118 }
1119
1120 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1121 {
1122         GElf_Phdr phdr;
1123         size_t i, phdrnum;
1124         int err;
1125         u64 sz;
1126
1127         if (elf_getphdrnum(elf, &phdrnum))
1128                 return -1;
1129
1130         for (i = 0; i < phdrnum; i++) {
1131                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1132                         return -1;
1133                 if (phdr.p_type != PT_LOAD)
1134                         continue;
1135                 if (exe) {
1136                         if (!(phdr.p_flags & PF_X))
1137                                 continue;
1138                 } else {
1139                         if (!(phdr.p_flags & PF_R))
1140                                 continue;
1141                 }
1142                 sz = min(phdr.p_memsz, phdr.p_filesz);
1143                 if (!sz)
1144                         continue;
1145                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1146                 if (err)
1147                         return err;
1148         }
1149         return 0;
1150 }
1151
1152 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1153                     bool *is_64_bit)
1154 {
1155         int err;
1156         Elf *elf;
1157
1158         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1159         if (elf == NULL)
1160                 return -1;
1161
1162         if (is_64_bit)
1163                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1164
1165         err = elf_read_maps(elf, exe, mapfn, data);
1166
1167         elf_end(elf);
1168         return err;
1169 }
1170
1171 enum dso_type dso__type_fd(int fd)
1172 {
1173         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1174         GElf_Ehdr ehdr;
1175         Elf_Kind ek;
1176         Elf *elf;
1177
1178         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1179         if (elf == NULL)
1180                 goto out;
1181
1182         ek = elf_kind(elf);
1183         if (ek != ELF_K_ELF)
1184                 goto out_end;
1185
1186         if (gelf_getclass(elf) == ELFCLASS64) {
1187                 dso_type = DSO__TYPE_64BIT;
1188                 goto out_end;
1189         }
1190
1191         if (gelf_getehdr(elf, &ehdr) == NULL)
1192                 goto out_end;
1193
1194         if (ehdr.e_machine == EM_X86_64)
1195                 dso_type = DSO__TYPE_X32BIT;
1196         else
1197                 dso_type = DSO__TYPE_32BIT;
1198 out_end:
1199         elf_end(elf);
1200 out:
1201         return dso_type;
1202 }
1203
1204 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1205 {
1206         ssize_t r;
1207         size_t n;
1208         int err = -1;
1209         char *buf = malloc(page_size);
1210
1211         if (buf == NULL)
1212                 return -1;
1213
1214         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1215                 goto out;
1216
1217         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1218                 goto out;
1219
1220         while (len) {
1221                 n = page_size;
1222                 if (len < n)
1223                         n = len;
1224                 /* Use read because mmap won't work on proc files */
1225                 r = read(from, buf, n);
1226                 if (r < 0)
1227                         goto out;
1228                 if (!r)
1229                         break;
1230                 n = r;
1231                 r = write(to, buf, n);
1232                 if (r < 0)
1233                         goto out;
1234                 if ((size_t)r != n)
1235                         goto out;
1236                 len -= n;
1237         }
1238
1239         err = 0;
1240 out:
1241         free(buf);
1242         return err;
1243 }
1244
1245 struct kcore {
1246         int fd;
1247         int elfclass;
1248         Elf *elf;
1249         GElf_Ehdr ehdr;
1250 };
1251
1252 static int kcore__open(struct kcore *kcore, const char *filename)
1253 {
1254         GElf_Ehdr *ehdr;
1255
1256         kcore->fd = open(filename, O_RDONLY);
1257         if (kcore->fd == -1)
1258                 return -1;
1259
1260         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1261         if (!kcore->elf)
1262                 goto out_close;
1263
1264         kcore->elfclass = gelf_getclass(kcore->elf);
1265         if (kcore->elfclass == ELFCLASSNONE)
1266                 goto out_end;
1267
1268         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1269         if (!ehdr)
1270                 goto out_end;
1271
1272         return 0;
1273
1274 out_end:
1275         elf_end(kcore->elf);
1276 out_close:
1277         close(kcore->fd);
1278         return -1;
1279 }
1280
1281 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1282                        bool temp)
1283 {
1284         kcore->elfclass = elfclass;
1285
1286         if (temp)
1287                 kcore->fd = mkstemp(filename);
1288         else
1289                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1290         if (kcore->fd == -1)
1291                 return -1;
1292
1293         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1294         if (!kcore->elf)
1295                 goto out_close;
1296
1297         if (!gelf_newehdr(kcore->elf, elfclass))
1298                 goto out_end;
1299
1300         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1301
1302         return 0;
1303
1304 out_end:
1305         elf_end(kcore->elf);
1306 out_close:
1307         close(kcore->fd);
1308         unlink(filename);
1309         return -1;
1310 }
1311
1312 static void kcore__close(struct kcore *kcore)
1313 {
1314         elf_end(kcore->elf);
1315         close(kcore->fd);
1316 }
1317
1318 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1319 {
1320         GElf_Ehdr *ehdr = &to->ehdr;
1321         GElf_Ehdr *kehdr = &from->ehdr;
1322
1323         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1324         ehdr->e_type      = kehdr->e_type;
1325         ehdr->e_machine   = kehdr->e_machine;
1326         ehdr->e_version   = kehdr->e_version;
1327         ehdr->e_entry     = 0;
1328         ehdr->e_shoff     = 0;
1329         ehdr->e_flags     = kehdr->e_flags;
1330         ehdr->e_phnum     = count;
1331         ehdr->e_shentsize = 0;
1332         ehdr->e_shnum     = 0;
1333         ehdr->e_shstrndx  = 0;
1334
1335         if (from->elfclass == ELFCLASS32) {
1336                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1337                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1338                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1339         } else {
1340                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1341                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1342                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1343         }
1344
1345         if (!gelf_update_ehdr(to->elf, ehdr))
1346                 return -1;
1347
1348         if (!gelf_newphdr(to->elf, count))
1349                 return -1;
1350
1351         return 0;
1352 }
1353
1354 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1355                            u64 addr, u64 len)
1356 {
1357         GElf_Phdr phdr = {
1358                 .p_type         = PT_LOAD,
1359                 .p_flags        = PF_R | PF_W | PF_X,
1360                 .p_offset       = offset,
1361                 .p_vaddr        = addr,
1362                 .p_paddr        = 0,
1363                 .p_filesz       = len,
1364                 .p_memsz        = len,
1365                 .p_align        = page_size,
1366         };
1367
1368         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1369                 return -1;
1370
1371         return 0;
1372 }
1373
1374 static off_t kcore__write(struct kcore *kcore)
1375 {
1376         return elf_update(kcore->elf, ELF_C_WRITE);
1377 }
1378
1379 struct phdr_data {
1380         off_t offset;
1381         u64 addr;
1382         u64 len;
1383 };
1384
1385 struct kcore_copy_info {
1386         u64 stext;
1387         u64 etext;
1388         u64 first_symbol;
1389         u64 last_symbol;
1390         u64 first_module;
1391         u64 last_module_symbol;
1392         struct phdr_data kernel_map;
1393         struct phdr_data modules_map;
1394 };
1395
1396 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1397                                         u64 start)
1398 {
1399         struct kcore_copy_info *kci = arg;
1400
1401         if (!symbol_type__is_a(type, MAP__FUNCTION))
1402                 return 0;
1403
1404         if (strchr(name, '[')) {
1405                 if (start > kci->last_module_symbol)
1406                         kci->last_module_symbol = start;
1407                 return 0;
1408         }
1409
1410         if (!kci->first_symbol || start < kci->first_symbol)
1411                 kci->first_symbol = start;
1412
1413         if (!kci->last_symbol || start > kci->last_symbol)
1414                 kci->last_symbol = start;
1415
1416         if (!strcmp(name, "_stext")) {
1417                 kci->stext = start;
1418                 return 0;
1419         }
1420
1421         if (!strcmp(name, "_etext")) {
1422                 kci->etext = start;
1423                 return 0;
1424         }
1425
1426         return 0;
1427 }
1428
1429 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1430                                       const char *dir)
1431 {
1432         char kallsyms_filename[PATH_MAX];
1433
1434         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1435
1436         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1437                 return -1;
1438
1439         if (kallsyms__parse(kallsyms_filename, kci,
1440                             kcore_copy__process_kallsyms) < 0)
1441                 return -1;
1442
1443         return 0;
1444 }
1445
1446 static int kcore_copy__process_modules(void *arg,
1447                                        const char *name __maybe_unused,
1448                                        u64 start)
1449 {
1450         struct kcore_copy_info *kci = arg;
1451
1452         if (!kci->first_module || start < kci->first_module)
1453                 kci->first_module = start;
1454
1455         return 0;
1456 }
1457
1458 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1459                                      const char *dir)
1460 {
1461         char modules_filename[PATH_MAX];
1462
1463         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1464
1465         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1466                 return -1;
1467
1468         if (modules__parse(modules_filename, kci,
1469                            kcore_copy__process_modules) < 0)
1470                 return -1;
1471
1472         return 0;
1473 }
1474
1475 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1476                             u64 s, u64 e)
1477 {
1478         if (p->addr || s < start || s >= end)
1479                 return;
1480
1481         p->addr = s;
1482         p->offset = (s - start) + pgoff;
1483         p->len = e < end ? e - s : end - s;
1484 }
1485
1486 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1487 {
1488         struct kcore_copy_info *kci = data;
1489         u64 end = start + len;
1490
1491         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1492                         kci->etext);
1493
1494         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1495                         kci->last_module_symbol);
1496
1497         return 0;
1498 }
1499
1500 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1501 {
1502         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1503                 return -1;
1504
1505         return 0;
1506 }
1507
1508 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1509                                  Elf *elf)
1510 {
1511         if (kcore_copy__parse_kallsyms(kci, dir))
1512                 return -1;
1513
1514         if (kcore_copy__parse_modules(kci, dir))
1515                 return -1;
1516
1517         if (kci->stext)
1518                 kci->stext = round_down(kci->stext, page_size);
1519         else
1520                 kci->stext = round_down(kci->first_symbol, page_size);
1521
1522         if (kci->etext) {
1523                 kci->etext = round_up(kci->etext, page_size);
1524         } else if (kci->last_symbol) {
1525                 kci->etext = round_up(kci->last_symbol, page_size);
1526                 kci->etext += page_size;
1527         }
1528
1529         kci->first_module = round_down(kci->first_module, page_size);
1530
1531         if (kci->last_module_symbol) {
1532                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1533                                                    page_size);
1534                 kci->last_module_symbol += page_size;
1535         }
1536
1537         if (!kci->stext || !kci->etext)
1538                 return -1;
1539
1540         if (kci->first_module && !kci->last_module_symbol)
1541                 return -1;
1542
1543         return kcore_copy__read_maps(kci, elf);
1544 }
1545
1546 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1547                                  const char *name)
1548 {
1549         char from_filename[PATH_MAX];
1550         char to_filename[PATH_MAX];
1551
1552         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1553         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1554
1555         return copyfile_mode(from_filename, to_filename, 0400);
1556 }
1557
1558 static int kcore_copy__unlink(const char *dir, const char *name)
1559 {
1560         char filename[PATH_MAX];
1561
1562         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1563
1564         return unlink(filename);
1565 }
1566
1567 static int kcore_copy__compare_fds(int from, int to)
1568 {
1569         char *buf_from;
1570         char *buf_to;
1571         ssize_t ret;
1572         size_t len;
1573         int err = -1;
1574
1575         buf_from = malloc(page_size);
1576         buf_to = malloc(page_size);
1577         if (!buf_from || !buf_to)
1578                 goto out;
1579
1580         while (1) {
1581                 /* Use read because mmap won't work on proc files */
1582                 ret = read(from, buf_from, page_size);
1583                 if (ret < 0)
1584                         goto out;
1585
1586                 if (!ret)
1587                         break;
1588
1589                 len = ret;
1590
1591                 if (readn(to, buf_to, len) != (int)len)
1592                         goto out;
1593
1594                 if (memcmp(buf_from, buf_to, len))
1595                         goto out;
1596         }
1597
1598         err = 0;
1599 out:
1600         free(buf_to);
1601         free(buf_from);
1602         return err;
1603 }
1604
1605 static int kcore_copy__compare_files(const char *from_filename,
1606                                      const char *to_filename)
1607 {
1608         int from, to, err = -1;
1609
1610         from = open(from_filename, O_RDONLY);
1611         if (from < 0)
1612                 return -1;
1613
1614         to = open(to_filename, O_RDONLY);
1615         if (to < 0)
1616                 goto out_close_from;
1617
1618         err = kcore_copy__compare_fds(from, to);
1619
1620         close(to);
1621 out_close_from:
1622         close(from);
1623         return err;
1624 }
1625
1626 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1627                                     const char *name)
1628 {
1629         char from_filename[PATH_MAX];
1630         char to_filename[PATH_MAX];
1631
1632         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1633         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1634
1635         return kcore_copy__compare_files(from_filename, to_filename);
1636 }
1637
1638 /**
1639  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1640  * @from_dir: from directory
1641  * @to_dir: to directory
1642  *
1643  * This function copies kallsyms, modules and kcore files from one directory to
1644  * another.  kallsyms and modules are copied entirely.  Only code segments are
1645  * copied from kcore.  It is assumed that two segments suffice: one for the
1646  * kernel proper and one for all the modules.  The code segments are determined
1647  * from kallsyms and modules files.  The kernel map starts at _stext or the
1648  * lowest function symbol, and ends at _etext or the highest function symbol.
1649  * The module map starts at the lowest module address and ends at the highest
1650  * module symbol.  Start addresses are rounded down to the nearest page.  End
1651  * addresses are rounded up to the nearest page.  An extra page is added to the
1652  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1653  * symbol too.  Because it contains only code sections, the resulting kcore is
1654  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1655  * is not the same for the kernel map and the modules map.  That happens because
1656  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1657  * kallsyms and modules files are compared with their copies to check that
1658  * modules have not been loaded or unloaded while the copies were taking place.
1659  *
1660  * Return: %0 on success, %-1 on failure.
1661  */
1662 int kcore_copy(const char *from_dir, const char *to_dir)
1663 {
1664         struct kcore kcore;
1665         struct kcore extract;
1666         size_t count = 2;
1667         int idx = 0, err = -1;
1668         off_t offset = page_size, sz, modules_offset = 0;
1669         struct kcore_copy_info kci = { .stext = 0, };
1670         char kcore_filename[PATH_MAX];
1671         char extract_filename[PATH_MAX];
1672
1673         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1674                 return -1;
1675
1676         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1677                 goto out_unlink_kallsyms;
1678
1679         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1680         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1681
1682         if (kcore__open(&kcore, kcore_filename))
1683                 goto out_unlink_modules;
1684
1685         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1686                 goto out_kcore_close;
1687
1688         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1689                 goto out_kcore_close;
1690
1691         if (!kci.modules_map.addr)
1692                 count -= 1;
1693
1694         if (kcore__copy_hdr(&kcore, &extract, count))
1695                 goto out_extract_close;
1696
1697         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1698                             kci.kernel_map.len))
1699                 goto out_extract_close;
1700
1701         if (kci.modules_map.addr) {
1702                 modules_offset = offset + kci.kernel_map.len;
1703                 if (kcore__add_phdr(&extract, idx, modules_offset,
1704                                     kci.modules_map.addr, kci.modules_map.len))
1705                         goto out_extract_close;
1706         }
1707
1708         sz = kcore__write(&extract);
1709         if (sz < 0 || sz > offset)
1710                 goto out_extract_close;
1711
1712         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1713                        kci.kernel_map.len))
1714                 goto out_extract_close;
1715
1716         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1717                                          extract.fd, modules_offset,
1718                                          kci.modules_map.len))
1719                 goto out_extract_close;
1720
1721         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1722                 goto out_extract_close;
1723
1724         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1725                 goto out_extract_close;
1726
1727         err = 0;
1728
1729 out_extract_close:
1730         kcore__close(&extract);
1731         if (err)
1732                 unlink(extract_filename);
1733 out_kcore_close:
1734         kcore__close(&kcore);
1735 out_unlink_modules:
1736         if (err)
1737                 kcore_copy__unlink(to_dir, "modules");
1738 out_unlink_kallsyms:
1739         if (err)
1740                 kcore_copy__unlink(to_dir, "kallsyms");
1741
1742         return err;
1743 }
1744
1745 int kcore_extract__create(struct kcore_extract *kce)
1746 {
1747         struct kcore kcore;
1748         struct kcore extract;
1749         size_t count = 1;
1750         int idx = 0, err = -1;
1751         off_t offset = page_size, sz;
1752
1753         if (kcore__open(&kcore, kce->kcore_filename))
1754                 return -1;
1755
1756         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1757         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1758                 goto out_kcore_close;
1759
1760         if (kcore__copy_hdr(&kcore, &extract, count))
1761                 goto out_extract_close;
1762
1763         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1764                 goto out_extract_close;
1765
1766         sz = kcore__write(&extract);
1767         if (sz < 0 || sz > offset)
1768                 goto out_extract_close;
1769
1770         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1771                 goto out_extract_close;
1772
1773         err = 0;
1774
1775 out_extract_close:
1776         kcore__close(&extract);
1777         if (err)
1778                 unlink(kce->extract_filename);
1779 out_kcore_close:
1780         kcore__close(&kcore);
1781
1782         return err;
1783 }
1784
1785 void kcore_extract__delete(struct kcore_extract *kce)
1786 {
1787         unlink(kce->extract_filename);
1788 }
1789
1790 void symbol__elf_init(void)
1791 {
1792         elf_version(EV_CURRENT);
1793 }