kernel/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 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 634                  enum dso_binary_type type)
 635 {
 636         int err = -1;
 637         GElf_Ehdr ehdr;
 638         Elf *elf;
 639         int fd;
 640
 641         if (dso__needs_decompress(dso)) {
 642                 fd = decompress_kmodule(dso, name, type);
 643                 if (fd < 0)
 644                         return -1;
 645         } else {
 646                 fd = open(name, O_RDONLY);
 647                 if (fd < 0) {
 648                         dso->load_errno = errno;
 649                         return -1;
 650                 }
 651         }
 652
 653         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 654         if (elf == NULL) {
 655                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 656                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 657                 goto out_close;
 658         }
 659
 660         if (gelf_getehdr(elf, &ehdr) == NULL) {
 661                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 662                 pr_debug("%s: cannot get elf header.\n", __func__);
 663                 goto out_elf_end;
 664         }
 665
 666         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 667                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 668                 goto out_elf_end;
 669         }
 670
 671         /* Always reject images with a mismatched build-id: */
 672         if (dso->has_build_id) {
 673                 u8 build_id[BUILD_ID_SIZE];
 674
 675                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 676                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 677                         goto out_elf_end;
 678                 }
 679
 680                 if (!dso__build_id_equal(dso, build_id)) {
 681                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 682                         goto out_elf_end;
 683                 }
 684         }
 685
 686         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 687
 688         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 689                         NULL);
 690         if (ss->symshdr.sh_type != SHT_SYMTAB)
 691                 ss->symtab = NULL;
 692
 693         ss->dynsym_idx = 0;
 694         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 695                         &ss->dynsym_idx);
 696         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 697                 ss->dynsym = NULL;
 698
 699         ss->opdidx = 0;
 700         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 701                         &ss->opdidx);
 702         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 703                 ss->opdsec = NULL;
 704
 705         if (dso->kernel == DSO_TYPE_USER) {
 706                 GElf_Shdr shdr;
 707                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 708                                 ehdr.e_type == ET_REL ||
 709                                 dso__is_vdso(dso) ||
 710                                 elf_section_by_name(elf, &ehdr, &shdr,
 711                                                      ".gnu.prelink_undo",
 712                                                      NULL) != NULL);
 713         } else {
 714                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 715                                      ehdr.e_type == ET_REL;
 716         }
 717
 718         ss->name   = strdup(name);
 719         if (!ss->name) {
 720                 dso->load_errno = errno;
 721                 goto out_elf_end;
 722         }
 723
 724         ss->elf    = elf;
 725         ss->fd     = fd;
 726         ss->ehdr   = ehdr;
 727         ss->type   = type;
 728
 729         return 0;
 730
 731 out_elf_end:
 732         elf_end(elf);
 733 out_close:
 734         close(fd);
 735         return err;
 736 }
 737
 738 /**
 739  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 740  * @kmap: kernel maps and relocation reference symbol
 741  *
 742  * This function returns %true if we are dealing with the kernel maps and the
 743  * relocation reference symbol has not yet been found.  Otherwise %false is
 744  * returned.
 745  */
 746 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 747 {
 748         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 749                !kmap->ref_reloc_sym->unrelocated_addr;
 750 }
 751
 752 /**
 753  * ref_reloc - kernel relocation offset.
 754  * @kmap: kernel maps and relocation reference symbol
 755  *
 756  * This function returns the offset of kernel addresses as determined by using
 757  * the relocation reference symbol i.e. if the kernel has not been relocated
 758  * then the return value is zero.
 759  */
 760 static u64 ref_reloc(struct kmap *kmap)
 761 {
 762         if (kmap && kmap->ref_reloc_sym &&
 763             kmap->ref_reloc_sym->unrelocated_addr)
 764                 return kmap->ref_reloc_sym->addr -
 765                        kmap->ref_reloc_sym->unrelocated_addr;
 766         return 0;
 767 }
 768
 769 static bool want_demangle(bool is_kernel_sym)
 770 {
 771         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 772 }
 773
 774 int dso__load_sym(struct dso *dso, struct map *map,
 775                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 776                   symbol_filter_t filter, int kmodule)
 777 {
 778         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 779         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 780         struct map *curr_map = map;
 781         struct dso *curr_dso = dso;
 782         Elf_Data *symstrs, *secstrs;
 783         uint32_t nr_syms;
 784         int err = -1;
 785         uint32_t idx;
 786         GElf_Ehdr ehdr;
 787         GElf_Shdr shdr;
 788         Elf_Data *syms, *opddata = NULL;
 789         GElf_Sym sym;
 790         Elf_Scn *sec, *sec_strndx;
 791         Elf *elf;
 792         int nr = 0;
 793         bool remap_kernel = false, adjust_kernel_syms = false;
 794
 795         if (kmap && !kmaps)
 796                 return -1;
 797
 798         dso->symtab_type = syms_ss->type;
 799         dso->is_64_bit = syms_ss->is_64_bit;
 800         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 801
 802         /*
 803          * Modules may already have symbols from kallsyms, but those symbols
 804          * have the wrong values for the dso maps, so remove them.
 805          */
 806         if (kmodule && syms_ss->symtab)
 807                 symbols__delete(&dso->symbols[map->type]);
 808
 809         if (!syms_ss->symtab) {
 810                 /*
 811                  * If the vmlinux is stripped, fail so we will fall back
 812                  * to using kallsyms. The vmlinux runtime symbols aren't
 813                  * of much use.
 814                  */
 815                 if (dso->kernel)
 816                         goto out_elf_end;
 817
 818                 syms_ss->symtab  = syms_ss->dynsym;
 819                 syms_ss->symshdr = syms_ss->dynshdr;
 820         }
 821
 822         elf = syms_ss->elf;
 823         ehdr = syms_ss->ehdr;
 824         sec = syms_ss->symtab;
 825         shdr = syms_ss->symshdr;
 826
 827         if (runtime_ss->opdsec)
 828                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 829
 830         syms = elf_getdata(sec, NULL);
 831         if (syms == NULL)
 832                 goto out_elf_end;
 833
 834         sec = elf_getscn(elf, shdr.sh_link);
 835         if (sec == NULL)
 836                 goto out_elf_end;
 837
 838         symstrs = elf_getdata(sec, NULL);
 839         if (symstrs == NULL)
 840                 goto out_elf_end;
 841
 842         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 843         if (sec_strndx == NULL)
 844                 goto out_elf_end;
 845
 846         secstrs = elf_getdata(sec_strndx, NULL);
 847         if (secstrs == NULL)
 848                 goto out_elf_end;
 849
 850         nr_syms = shdr.sh_size / shdr.sh_entsize;
 851
 852         memset(&sym, 0, sizeof(sym));
 853
 854         /*
 855          * The kernel relocation symbol is needed in advance in order to adjust
 856          * kernel maps correctly.
 857          */
 858         if (ref_reloc_sym_not_found(kmap)) {
 859                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 860                         const char *elf_name = elf_sym__name(&sym, symstrs);
 861
 862                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 863                                 continue;
 864                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 865                         map->reloc = kmap->ref_reloc_sym->addr -
 866                                      kmap->ref_reloc_sym->unrelocated_addr;
 867                         break;
 868                 }
 869         }
 870
 871         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 872         /*
 873          * Initial kernel and module mappings do not map to the dso.  For
 874          * function mappings, flag the fixups.
 875          */
 876         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 877                 remap_kernel = true;
 878                 adjust_kernel_syms = dso->adjust_symbols;
 879         }
 880         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 881                 struct symbol *f;
 882                 const char *elf_name = elf_sym__name(&sym, symstrs);
 883                 char *demangled = NULL;
 884                 int is_label = elf_sym__is_label(&sym);
 885                 const char *section_name;
 886                 bool used_opd = false;
 887
 888                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 889                         continue;
 890
 891                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 892                  * don't identify functions, so will confuse the profile
 893                  * output: */
 894                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 895                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 896                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 897                                 continue;
 898                 }
 899
 900                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 901                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 902                         u64 *opd = opddata->d_buf + offset;
 903                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 904                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 905                                         sym.st_value);
 906                         used_opd = true;
 907                 }
 908                 /*
 909                  * When loading symbols in a data mapping, ABS symbols (which
 910                  * has a value of SHN_ABS in its st_shndx) failed at
 911                  * elf_getscn().  And it marks the loading as a failure so
 912                  * already loaded symbols cannot be fixed up.
 913                  *
 914                  * I'm not sure what should be done. Just ignore them for now.
 915                  * - Namhyung Kim
 916                  */
 917                 if (sym.st_shndx == SHN_ABS)
 918                         continue;
 919
 920                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 921                 if (!sec)
 922                         goto out_elf_end;
 923
 924                 gelf_getshdr(sec, &shdr);
 925
 926                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 927                         continue;
 928
 929                 section_name = elf_sec__name(&shdr, secstrs);
 930
 931                 /* On ARM, symbols for thumb functions have 1 added to
 932                  * the symbol address as a flag - remove it */
 933                 if ((ehdr.e_machine == EM_ARM) &&
 934                     (map->type == MAP__FUNCTION) &&
 935                     (sym.st_value & 1))
 936                         --sym.st_value;
 937
 938                 if (dso->kernel || kmodule) {
 939                         char dso_name[PATH_MAX];
 940
 941                         /* Adjust symbol to map to file offset */
 942                         if (adjust_kernel_syms)
 943                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 944
 945                         if (strcmp(section_name,
 946                                    (curr_dso->short_name +
 947                                     dso->short_name_len)) == 0)
 948                                 goto new_symbol;
 949
 950                         if (strcmp(section_name, ".text") == 0) {
 951                                 /*
 952                                  * The initial kernel mapping is based on
 953                                  * kallsyms and identity maps.  Overwrite it to
 954                                  * map to the kernel dso.
 955                                  */
 956                                 if (remap_kernel && dso->kernel) {
 957                                         remap_kernel = false;
 958                                         map->start = shdr.sh_addr +
 959                                                      ref_reloc(kmap);
 960                                         map->end = map->start + shdr.sh_size;
 961                                         map->pgoff = shdr.sh_offset;
 962                                         map->map_ip = map__map_ip;
 963                                         map->unmap_ip = map__unmap_ip;
 964                                         /* Ensure maps are correctly ordered */
 965                                         if (kmaps) {
 966                                                 map_groups__remove(kmaps, map);
 967                                                 map_groups__insert(kmaps, map);
 968                                         }
 969                                 }
 970
 971                                 /*
 972                                  * The initial module mapping is based on
 973                                  * /proc/modules mapped to offset zero.
 974                                  * Overwrite it to map to the module dso.
 975                                  */
 976                                 if (remap_kernel && kmodule) {
 977                                         remap_kernel = false;
 978                                         map->pgoff = shdr.sh_offset;
 979                                 }
 980
 981                                 curr_map = map;
 982                                 curr_dso = dso;
 983                                 goto new_symbol;
 984                         }
 985
 986                         if (!kmap)
 987                                 goto new_symbol;
 988
 989                         snprintf(dso_name, sizeof(dso_name),
 990                                  "%s%s", dso->short_name, section_name);
 991
 992                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
 993                         if (curr_map == NULL) {
 994                                 u64 start = sym.st_value;
 995
 996                                 if (kmodule)
 997                                         start += map->start + shdr.sh_offset;
 998
 999                                 curr_dso = dso__new(dso_name);
1000                                 if (curr_dso == NULL)
1001                                         goto out_elf_end;
1002                                 curr_dso->kernel = dso->kernel;
1003                                 curr_dso->long_name = dso->long_name;
1004                                 curr_dso->long_name_len = dso->long_name_len;
1005                                 curr_map = map__new2(start, curr_dso,
1006                                                      map->type);
1007                                 if (curr_map == NULL) {
1008                                         dso__delete(curr_dso);
1009                                         goto out_elf_end;
1010                                 }
1011                                 if (adjust_kernel_syms) {
1012                                         curr_map->start = shdr.sh_addr +
1013                                                           ref_reloc(kmap);
1014                                         curr_map->end = curr_map->start +
1015                                                         shdr.sh_size;
1016                                         curr_map->pgoff = shdr.sh_offset;
1017                                 } else {
1018                                         curr_map->map_ip = identity__map_ip;
1019                                         curr_map->unmap_ip = identity__map_ip;
1020                                 }
1021                                 curr_dso->symtab_type = dso->symtab_type;
1022                                 map_groups__insert(kmaps, curr_map);
1023                                 /*
1024                                  * The new DSO should go to the kernel DSOS
1025                                  */
1026                                 dsos__add(&map->groups->machine->kernel_dsos,
1027                                           curr_dso);
1028                                 dso__set_loaded(curr_dso, map->type);
1029                         } else
1030                                 curr_dso = curr_map->dso;
1031
1032                         goto new_symbol;
1033                 }
1034
1035                 if ((used_opd && runtime_ss->adjust_symbols)
1036                                 || (!used_opd && syms_ss->adjust_symbols)) {
1037                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1038                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1039                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1040                                   (u64)shdr.sh_offset);
1041                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1042                 }
1043 new_symbol:
1044                 /*
1045                  * We need to figure out if the object was created from C++ sources
1046                  * DWARF DW_compile_unit has this, but we don't always have access
1047                  * to it...
1048                  */
1049                 if (want_demangle(dso->kernel || kmodule)) {
1050                         int demangle_flags = DMGL_NO_OPTS;
1051                         if (verbose)
1052                                 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1053
1054                         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1055                         if (demangled != NULL)
1056                                 elf_name = demangled;
1057                 }
1058                 f = symbol__new(sym.st_value, sym.st_size,
1059                                 GELF_ST_BIND(sym.st_info), elf_name);
1060                 free(demangled);
1061                 if (!f)
1062                         goto out_elf_end;
1063
1064                 if (filter && filter(curr_map, f))
1065                         symbol__delete(f);
1066                 else {
1067                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
1068                         nr++;
1069                 }
1070         }
1071
1072         /*
1073          * For misannotated, zeroed, ASM function sizes.
1074          */
1075         if (nr > 0) {
1076                 if (!symbol_conf.allow_aliases)
1077                         symbols__fixup_duplicate(&dso->symbols[map->type]);
1078                 symbols__fixup_end(&dso->symbols[map->type]);
1079                 if (kmap) {
1080                         /*
1081                          * We need to fixup this here too because we create new
1082                          * maps here, for things like vsyscall sections.
1083                          */
1084                         __map_groups__fixup_end(kmaps, map->type);
1085                 }
1086         }
1087         err = nr;
1088 out_elf_end:
1089         return err;
1090 }
1091
1092 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1093 {
1094         GElf_Phdr phdr;
1095         size_t i, phdrnum;
1096         int err;
1097         u64 sz;
1098
1099         if (elf_getphdrnum(elf, &phdrnum))
1100                 return -1;
1101
1102         for (i = 0; i < phdrnum; i++) {
1103                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1104                         return -1;
1105                 if (phdr.p_type != PT_LOAD)
1106                         continue;
1107                 if (exe) {
1108                         if (!(phdr.p_flags & PF_X))
1109                                 continue;
1110                 } else {
1111                         if (!(phdr.p_flags & PF_R))
1112                                 continue;
1113                 }
1114                 sz = min(phdr.p_memsz, phdr.p_filesz);
1115                 if (!sz)
1116                         continue;
1117                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1118                 if (err)
1119                         return err;
1120         }
1121         return 0;
1122 }
1123
1124 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1125                     bool *is_64_bit)
1126 {
1127         int err;
1128         Elf *elf;
1129
1130         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1131         if (elf == NULL)
1132                 return -1;
1133
1134         if (is_64_bit)
1135                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1136
1137         err = elf_read_maps(elf, exe, mapfn, data);
1138
1139         elf_end(elf);
1140         return err;
1141 }
1142
1143 enum dso_type dso__type_fd(int fd)
1144 {
1145         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1146         GElf_Ehdr ehdr;
1147         Elf_Kind ek;
1148         Elf *elf;
1149
1150         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1151         if (elf == NULL)
1152                 goto out;
1153
1154         ek = elf_kind(elf);
1155         if (ek != ELF_K_ELF)
1156                 goto out_end;
1157
1158         if (gelf_getclass(elf) == ELFCLASS64) {
1159                 dso_type = DSO__TYPE_64BIT;
1160                 goto out_end;
1161         }
1162
1163         if (gelf_getehdr(elf, &ehdr) == NULL)
1164                 goto out_end;
1165
1166         if (ehdr.e_machine == EM_X86_64)
1167                 dso_type = DSO__TYPE_X32BIT;
1168         else
1169                 dso_type = DSO__TYPE_32BIT;
1170 out_end:
1171         elf_end(elf);
1172 out:
1173         return dso_type;
1174 }
1175
1176 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1177 {
1178         ssize_t r;
1179         size_t n;
1180         int err = -1;
1181         char *buf = malloc(page_size);
1182
1183         if (buf == NULL)
1184                 return -1;
1185
1186         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1187                 goto out;
1188
1189         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1190                 goto out;
1191
1192         while (len) {
1193                 n = page_size;
1194                 if (len < n)
1195                         n = len;
1196                 /* Use read because mmap won't work on proc files */
1197                 r = read(from, buf, n);
1198                 if (r < 0)
1199                         goto out;
1200                 if (!r)
1201                         break;
1202                 n = r;
1203                 r = write(to, buf, n);
1204                 if (r < 0)
1205                         goto out;
1206                 if ((size_t)r != n)
1207                         goto out;
1208                 len -= n;
1209         }
1210
1211         err = 0;
1212 out:
1213         free(buf);
1214         return err;
1215 }
1216
1217 struct kcore {
1218         int fd;
1219         int elfclass;
1220         Elf *elf;
1221         GElf_Ehdr ehdr;
1222 };
1223
1224 static int kcore__open(struct kcore *kcore, const char *filename)
1225 {
1226         GElf_Ehdr *ehdr;
1227
1228         kcore->fd = open(filename, O_RDONLY);
1229         if (kcore->fd == -1)
1230                 return -1;
1231
1232         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1233         if (!kcore->elf)
1234                 goto out_close;
1235
1236         kcore->elfclass = gelf_getclass(kcore->elf);
1237         if (kcore->elfclass == ELFCLASSNONE)
1238                 goto out_end;
1239
1240         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1241         if (!ehdr)
1242                 goto out_end;
1243
1244         return 0;
1245
1246 out_end:
1247         elf_end(kcore->elf);
1248 out_close:
1249         close(kcore->fd);
1250         return -1;
1251 }
1252
1253 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1254                        bool temp)
1255 {
1256         GElf_Ehdr *ehdr;
1257
1258         kcore->elfclass = elfclass;
1259
1260         if (temp)
1261                 kcore->fd = mkstemp(filename);
1262         else
1263                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1264         if (kcore->fd == -1)
1265                 return -1;
1266
1267         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1268         if (!kcore->elf)
1269                 goto out_close;
1270
1271         if (!gelf_newehdr(kcore->elf, elfclass))
1272                 goto out_end;
1273
1274         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1275         if (!ehdr)
1276                 goto out_end;
1277
1278         return 0;
1279
1280 out_end:
1281         elf_end(kcore->elf);
1282 out_close:
1283         close(kcore->fd);
1284         unlink(filename);
1285         return -1;
1286 }
1287
1288 static void kcore__close(struct kcore *kcore)
1289 {
1290         elf_end(kcore->elf);
1291         close(kcore->fd);
1292 }
1293
1294 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1295 {
1296         GElf_Ehdr *ehdr = &to->ehdr;
1297         GElf_Ehdr *kehdr = &from->ehdr;
1298
1299         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1300         ehdr->e_type      = kehdr->e_type;
1301         ehdr->e_machine   = kehdr->e_machine;
1302         ehdr->e_version   = kehdr->e_version;
1303         ehdr->e_entry     = 0;
1304         ehdr->e_shoff     = 0;
1305         ehdr->e_flags     = kehdr->e_flags;
1306         ehdr->e_phnum     = count;
1307         ehdr->e_shentsize = 0;
1308         ehdr->e_shnum     = 0;
1309         ehdr->e_shstrndx  = 0;
1310
1311         if (from->elfclass == ELFCLASS32) {
1312                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1313                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1314                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1315         } else {
1316                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1317                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1318                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1319         }
1320
1321         if (!gelf_update_ehdr(to->elf, ehdr))
1322                 return -1;
1323
1324         if (!gelf_newphdr(to->elf, count))
1325                 return -1;
1326
1327         return 0;
1328 }
1329
1330 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1331                            u64 addr, u64 len)
1332 {
1333         GElf_Phdr gphdr;
1334         GElf_Phdr *phdr;
1335
1336         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1337         if (!phdr)
1338                 return -1;
1339
1340         phdr->p_type    = PT_LOAD;
1341         phdr->p_flags   = PF_R | PF_W | PF_X;
1342         phdr->p_offset  = offset;
1343         phdr->p_vaddr   = addr;
1344         phdr->p_paddr   = 0;
1345         phdr->p_filesz  = len;
1346         phdr->p_memsz   = len;
1347         phdr->p_align   = page_size;
1348
1349         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1350                 return -1;
1351
1352         return 0;
1353 }
1354
1355 static off_t kcore__write(struct kcore *kcore)
1356 {
1357         return elf_update(kcore->elf, ELF_C_WRITE);
1358 }
1359
1360 struct phdr_data {
1361         off_t offset;
1362         u64 addr;
1363         u64 len;
1364 };
1365
1366 struct kcore_copy_info {
1367         u64 stext;
1368         u64 etext;
1369         u64 first_symbol;
1370         u64 last_symbol;
1371         u64 first_module;
1372         u64 last_module_symbol;
1373         struct phdr_data kernel_map;
1374         struct phdr_data modules_map;
1375 };
1376
1377 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1378                                         u64 start)
1379 {
1380         struct kcore_copy_info *kci = arg;
1381
1382         if (!symbol_type__is_a(type, MAP__FUNCTION))
1383                 return 0;
1384
1385         if (strchr(name, '[')) {
1386                 if (start > kci->last_module_symbol)
1387                         kci->last_module_symbol = start;
1388                 return 0;
1389         }
1390
1391         if (!kci->first_symbol || start < kci->first_symbol)
1392                 kci->first_symbol = start;
1393
1394         if (!kci->last_symbol || start > kci->last_symbol)
1395                 kci->last_symbol = start;
1396
1397         if (!strcmp(name, "_stext")) {
1398                 kci->stext = start;
1399                 return 0;
1400         }
1401
1402         if (!strcmp(name, "_etext")) {
1403                 kci->etext = start;
1404                 return 0;
1405         }
1406
1407         return 0;
1408 }
1409
1410 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1411                                       const char *dir)
1412 {
1413         char kallsyms_filename[PATH_MAX];
1414
1415         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1416
1417         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1418                 return -1;
1419
1420         if (kallsyms__parse(kallsyms_filename, kci,
1421                             kcore_copy__process_kallsyms) < 0)
1422                 return -1;
1423
1424         return 0;
1425 }
1426
1427 static int kcore_copy__process_modules(void *arg,
1428                                        const char *name __maybe_unused,
1429                                        u64 start)
1430 {
1431         struct kcore_copy_info *kci = arg;
1432
1433         if (!kci->first_module || start < kci->first_module)
1434                 kci->first_module = start;
1435
1436         return 0;
1437 }
1438
1439 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1440                                      const char *dir)
1441 {
1442         char modules_filename[PATH_MAX];
1443
1444         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1445
1446         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1447                 return -1;
1448
1449         if (modules__parse(modules_filename, kci,
1450                            kcore_copy__process_modules) < 0)
1451                 return -1;
1452
1453         return 0;
1454 }
1455
1456 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1457                             u64 s, u64 e)
1458 {
1459         if (p->addr || s < start || s >= end)
1460                 return;
1461
1462         p->addr = s;
1463         p->offset = (s - start) + pgoff;
1464         p->len = e < end ? e - s : end - s;
1465 }
1466
1467 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1468 {
1469         struct kcore_copy_info *kci = data;
1470         u64 end = start + len;
1471
1472         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1473                         kci->etext);
1474
1475         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1476                         kci->last_module_symbol);
1477
1478         return 0;
1479 }
1480
1481 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1482 {
1483         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1484                 return -1;
1485
1486         return 0;
1487 }
1488
1489 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1490                                  Elf *elf)
1491 {
1492         if (kcore_copy__parse_kallsyms(kci, dir))
1493                 return -1;
1494
1495         if (kcore_copy__parse_modules(kci, dir))
1496                 return -1;
1497
1498         if (kci->stext)
1499                 kci->stext = round_down(kci->stext, page_size);
1500         else
1501                 kci->stext = round_down(kci->first_symbol, page_size);
1502
1503         if (kci->etext) {
1504                 kci->etext = round_up(kci->etext, page_size);
1505         } else if (kci->last_symbol) {
1506                 kci->etext = round_up(kci->last_symbol, page_size);
1507                 kci->etext += page_size;
1508         }
1509
1510         kci->first_module = round_down(kci->first_module, page_size);
1511
1512         if (kci->last_module_symbol) {
1513                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1514                                                    page_size);
1515                 kci->last_module_symbol += page_size;
1516         }
1517
1518         if (!kci->stext || !kci->etext)
1519                 return -1;
1520
1521         if (kci->first_module && !kci->last_module_symbol)
1522                 return -1;
1523
1524         return kcore_copy__read_maps(kci, elf);
1525 }
1526
1527 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1528                                  const char *name)
1529 {
1530         char from_filename[PATH_MAX];
1531         char to_filename[PATH_MAX];
1532
1533         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1534         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1535
1536         return copyfile_mode(from_filename, to_filename, 0400);
1537 }
1538
1539 static int kcore_copy__unlink(const char *dir, const char *name)
1540 {
1541         char filename[PATH_MAX];
1542
1543         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1544
1545         return unlink(filename);
1546 }
1547
1548 static int kcore_copy__compare_fds(int from, int to)
1549 {
1550         char *buf_from;
1551         char *buf_to;
1552         ssize_t ret;
1553         size_t len;
1554         int err = -1;
1555
1556         buf_from = malloc(page_size);
1557         buf_to = malloc(page_size);
1558         if (!buf_from || !buf_to)
1559                 goto out;
1560
1561         while (1) {
1562                 /* Use read because mmap won't work on proc files */
1563                 ret = read(from, buf_from, page_size);
1564                 if (ret < 0)
1565                         goto out;
1566
1567                 if (!ret)
1568                         break;
1569
1570                 len = ret;
1571
1572                 if (readn(to, buf_to, len) != (int)len)
1573                         goto out;
1574
1575                 if (memcmp(buf_from, buf_to, len))
1576                         goto out;
1577         }
1578
1579         err = 0;
1580 out:
1581         free(buf_to);
1582         free(buf_from);
1583         return err;
1584 }
1585
1586 static int kcore_copy__compare_files(const char *from_filename,
1587                                      const char *to_filename)
1588 {
1589         int from, to, err = -1;
1590
1591         from = open(from_filename, O_RDONLY);
1592         if (from < 0)
1593                 return -1;
1594
1595         to = open(to_filename, O_RDONLY);
1596         if (to < 0)
1597                 goto out_close_from;
1598
1599         err = kcore_copy__compare_fds(from, to);
1600
1601         close(to);
1602 out_close_from:
1603         close(from);
1604         return err;
1605 }
1606
1607 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1608                                     const char *name)
1609 {
1610         char from_filename[PATH_MAX];
1611         char to_filename[PATH_MAX];
1612
1613         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1614         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1615
1616         return kcore_copy__compare_files(from_filename, to_filename);
1617 }
1618
1619 /**
1620  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1621  * @from_dir: from directory
1622  * @to_dir: to directory
1623  *
1624  * This function copies kallsyms, modules and kcore files from one directory to
1625  * another.  kallsyms and modules are copied entirely.  Only code segments are
1626  * copied from kcore.  It is assumed that two segments suffice: one for the
1627  * kernel proper and one for all the modules.  The code segments are determined
1628  * from kallsyms and modules files.  The kernel map starts at _stext or the
1629  * lowest function symbol, and ends at _etext or the highest function symbol.
1630  * The module map starts at the lowest module address and ends at the highest
1631  * module symbol.  Start addresses are rounded down to the nearest page.  End
1632  * addresses are rounded up to the nearest page.  An extra page is added to the
1633  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1634  * symbol too.  Because it contains only code sections, the resulting kcore is
1635  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1636  * is not the same for the kernel map and the modules map.  That happens because
1637  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1638  * kallsyms and modules files are compared with their copies to check that
1639  * modules have not been loaded or unloaded while the copies were taking place.
1640  *
1641  * Return: %0 on success, %-1 on failure.
1642  */
1643 int kcore_copy(const char *from_dir, const char *to_dir)
1644 {
1645         struct kcore kcore;
1646         struct kcore extract;
1647         size_t count = 2;
1648         int idx = 0, err = -1;
1649         off_t offset = page_size, sz, modules_offset = 0;
1650         struct kcore_copy_info kci = { .stext = 0, };
1651         char kcore_filename[PATH_MAX];
1652         char extract_filename[PATH_MAX];
1653
1654         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1655                 return -1;
1656
1657         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1658                 goto out_unlink_kallsyms;
1659
1660         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1661         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1662
1663         if (kcore__open(&kcore, kcore_filename))
1664                 goto out_unlink_modules;
1665
1666         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1667                 goto out_kcore_close;
1668
1669         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1670                 goto out_kcore_close;
1671
1672         if (!kci.modules_map.addr)
1673                 count -= 1;
1674
1675         if (kcore__copy_hdr(&kcore, &extract, count))
1676                 goto out_extract_close;
1677
1678         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1679                             kci.kernel_map.len))
1680                 goto out_extract_close;
1681
1682         if (kci.modules_map.addr) {
1683                 modules_offset = offset + kci.kernel_map.len;
1684                 if (kcore__add_phdr(&extract, idx, modules_offset,
1685                                     kci.modules_map.addr, kci.modules_map.len))
1686                         goto out_extract_close;
1687         }
1688
1689         sz = kcore__write(&extract);
1690         if (sz < 0 || sz > offset)
1691                 goto out_extract_close;
1692
1693         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1694                        kci.kernel_map.len))
1695                 goto out_extract_close;
1696
1697         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1698                                          extract.fd, modules_offset,
1699                                          kci.modules_map.len))
1700                 goto out_extract_close;
1701
1702         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1703                 goto out_extract_close;
1704
1705         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1706                 goto out_extract_close;
1707
1708         err = 0;
1709
1710 out_extract_close:
1711         kcore__close(&extract);
1712         if (err)
1713                 unlink(extract_filename);
1714 out_kcore_close:
1715         kcore__close(&kcore);
1716 out_unlink_modules:
1717         if (err)
1718                 kcore_copy__unlink(to_dir, "modules");
1719 out_unlink_kallsyms:
1720         if (err)
1721                 kcore_copy__unlink(to_dir, "kallsyms");
1722
1723         return err;
1724 }
1725
1726 int kcore_extract__create(struct kcore_extract *kce)
1727 {
1728         struct kcore kcore;
1729         struct kcore extract;
1730         size_t count = 1;
1731         int idx = 0, err = -1;
1732         off_t offset = page_size, sz;
1733
1734         if (kcore__open(&kcore, kce->kcore_filename))
1735                 return -1;
1736
1737         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1738         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1739                 goto out_kcore_close;
1740
1741         if (kcore__copy_hdr(&kcore, &extract, count))
1742                 goto out_extract_close;
1743
1744         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1745                 goto out_extract_close;
1746
1747         sz = kcore__write(&extract);
1748         if (sz < 0 || sz > offset)
1749                 goto out_extract_close;
1750
1751         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1752                 goto out_extract_close;
1753
1754         err = 0;
1755
1756 out_extract_close:
1757         kcore__close(&extract);
1758         if (err)
1759                 unlink(kce->extract_filename);
1760 out_kcore_close:
1761         kcore__close(&kcore);
1762
1763         return err;
1764 }
1765
1766 void kcore_extract__delete(struct kcore_extract *kce)
1767 {
1768         unlink(kce->extract_filename);
1769 }
1770
1771 void symbol__elf_init(void)
1772 {
1773         elf_version(EV_CURRENT);
1774 }