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;
 583         const char *ext = strrchr(name, '.');
 584         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 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 (!ext || !is_supported_compression(ext + 1)) {
 592                 ext = strrchr(dso->name, '.');
 593                 if (!ext || !is_supported_compression(ext + 1))
 594                         return -1;
 595         }
 596
 597         fd = mkstemp(tmpbuf);
 598         if (fd < 0)
 599                 return -1;
 600
 601         if (!decompress_to_file(ext + 1, name, fd)) {
 602                 close(fd);
 603                 fd = -1;
 604         }
 605
 606         unlink(tmpbuf);
 607
 608         return fd;
 609 }
 610
 611 bool symsrc__possibly_runtime(struct symsrc *ss)
 612 {
 613         return ss->dynsym || ss->opdsec;
 614 }
 615
 616 bool symsrc__has_symtab(struct symsrc *ss)
 617 {
 618         return ss->symtab != NULL;
 619 }
 620
 621 void symsrc__destroy(struct symsrc *ss)
 622 {
 623         zfree(&ss->name);
 624         elf_end(ss->elf);
 625         close(ss->fd);
 626 }
 627
 628 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 629                  enum dso_binary_type type)
 630 {
 631         int err = -1;
 632         GElf_Ehdr ehdr;
 633         Elf *elf;
 634         int fd;
 635
 636         if (dso__needs_decompress(dso))
 637                 fd = decompress_kmodule(dso, name, type);
 638         else
 639                 fd = open(name, O_RDONLY);
 640
 641         if (fd < 0)
 642                 return -1;
 643
 644         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 645         if (elf == NULL) {
 646                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 647                 goto out_close;
 648         }
 649
 650         if (gelf_getehdr(elf, &ehdr) == NULL) {
 651                 pr_debug("%s: cannot get elf header.\n", __func__);
 652                 goto out_elf_end;
 653         }
 654
 655         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 656                 goto out_elf_end;
 657
 658         /* Always reject images with a mismatched build-id: */
 659         if (dso->has_build_id) {
 660                 u8 build_id[BUILD_ID_SIZE];
 661
 662                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 663                         goto out_elf_end;
 664
 665                 if (!dso__build_id_equal(dso, build_id))
 666                         goto out_elf_end;
 667         }
 668
 669         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 670
 671         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 672                         NULL);
 673         if (ss->symshdr.sh_type != SHT_SYMTAB)
 674                 ss->symtab = NULL;
 675
 676         ss->dynsym_idx = 0;
 677         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 678                         &ss->dynsym_idx);
 679         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 680                 ss->dynsym = NULL;
 681
 682         ss->opdidx = 0;
 683         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 684                         &ss->opdidx);
 685         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 686                 ss->opdsec = NULL;
 687
 688         if (dso->kernel == DSO_TYPE_USER) {
 689                 GElf_Shdr shdr;
 690                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 691                                 ehdr.e_type == ET_REL ||
 692                                 dso__is_vdso(dso) ||
 693                                 elf_section_by_name(elf, &ehdr, &shdr,
 694                                                      ".gnu.prelink_undo",
 695                                                      NULL) != NULL);
 696         } else {
 697                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 698                                      ehdr.e_type == ET_REL;
 699         }
 700
 701         ss->name   = strdup(name);
 702         if (!ss->name)
 703                 goto out_elf_end;
 704
 705         ss->elf    = elf;
 706         ss->fd     = fd;
 707         ss->ehdr   = ehdr;
 708         ss->type   = type;
 709
 710         return 0;
 711
 712 out_elf_end:
 713         elf_end(elf);
 714 out_close:
 715         close(fd);
 716         return err;
 717 }
 718
 719 /**
 720  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 721  * @kmap: kernel maps and relocation reference symbol
 722  *
 723  * This function returns %true if we are dealing with the kernel maps and the
 724  * relocation reference symbol has not yet been found.  Otherwise %false is
 725  * returned.
 726  */
 727 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 728 {
 729         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 730                !kmap->ref_reloc_sym->unrelocated_addr;
 731 }
 732
 733 /**
 734  * ref_reloc - kernel relocation offset.
 735  * @kmap: kernel maps and relocation reference symbol
 736  *
 737  * This function returns the offset of kernel addresses as determined by using
 738  * the relocation reference symbol i.e. if the kernel has not been relocated
 739  * then the return value is zero.
 740  */
 741 static u64 ref_reloc(struct kmap *kmap)
 742 {
 743         if (kmap && kmap->ref_reloc_sym &&
 744             kmap->ref_reloc_sym->unrelocated_addr)
 745                 return kmap->ref_reloc_sym->addr -
 746                        kmap->ref_reloc_sym->unrelocated_addr;
 747         return 0;
 748 }
 749
 750 static bool want_demangle(bool is_kernel_sym)
 751 {
 752         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 753 }
 754
 755 int dso__load_sym(struct dso *dso, struct map *map,
 756                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 757                   symbol_filter_t filter, int kmodule)
 758 {
 759         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 760         struct map *curr_map = map;
 761         struct dso *curr_dso = dso;
 762         Elf_Data *symstrs, *secstrs;
 763         uint32_t nr_syms;
 764         int err = -1;
 765         uint32_t idx;
 766         GElf_Ehdr ehdr;
 767         GElf_Shdr shdr;
 768         Elf_Data *syms, *opddata = NULL;
 769         GElf_Sym sym;
 770         Elf_Scn *sec, *sec_strndx;
 771         Elf *elf;
 772         int nr = 0;
 773         bool remap_kernel = false, adjust_kernel_syms = false;
 774
 775         dso->symtab_type = syms_ss->type;
 776         dso->is_64_bit = syms_ss->is_64_bit;
 777         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 778
 779         /*
 780          * Modules may already have symbols from kallsyms, but those symbols
 781          * have the wrong values for the dso maps, so remove them.
 782          */
 783         if (kmodule && syms_ss->symtab)
 784                 symbols__delete(&dso->symbols[map->type]);
 785
 786         if (!syms_ss->symtab) {
 787                 /*
 788                  * If the vmlinux is stripped, fail so we will fall back
 789                  * to using kallsyms. The vmlinux runtime symbols aren't
 790                  * of much use.
 791                  */
 792                 if (dso->kernel)
 793                         goto out_elf_end;
 794
 795                 syms_ss->symtab  = syms_ss->dynsym;
 796                 syms_ss->symshdr = syms_ss->dynshdr;
 797         }
 798
 799         elf = syms_ss->elf;
 800         ehdr = syms_ss->ehdr;
 801         sec = syms_ss->symtab;
 802         shdr = syms_ss->symshdr;
 803
 804         if (runtime_ss->opdsec)
 805                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 806
 807         syms = elf_getdata(sec, NULL);
 808         if (syms == NULL)
 809                 goto out_elf_end;
 810
 811         sec = elf_getscn(elf, shdr.sh_link);
 812         if (sec == NULL)
 813                 goto out_elf_end;
 814
 815         symstrs = elf_getdata(sec, NULL);
 816         if (symstrs == NULL)
 817                 goto out_elf_end;
 818
 819         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 820         if (sec_strndx == NULL)
 821                 goto out_elf_end;
 822
 823         secstrs = elf_getdata(sec_strndx, NULL);
 824         if (secstrs == NULL)
 825                 goto out_elf_end;
 826
 827         nr_syms = shdr.sh_size / shdr.sh_entsize;
 828
 829         memset(&sym, 0, sizeof(sym));
 830
 831         /*
 832          * The kernel relocation symbol is needed in advance in order to adjust
 833          * kernel maps correctly.
 834          */
 835         if (ref_reloc_sym_not_found(kmap)) {
 836                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 837                         const char *elf_name = elf_sym__name(&sym, symstrs);
 838
 839                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 840                                 continue;
 841                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 842                         map->reloc = kmap->ref_reloc_sym->addr -
 843                                      kmap->ref_reloc_sym->unrelocated_addr;
 844                         break;
 845                 }
 846         }
 847
 848         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 849         /*
 850          * Initial kernel and module mappings do not map to the dso.  For
 851          * function mappings, flag the fixups.
 852          */
 853         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 854                 remap_kernel = true;
 855                 adjust_kernel_syms = dso->adjust_symbols;
 856         }
 857         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 858                 struct symbol *f;
 859                 const char *elf_name = elf_sym__name(&sym, symstrs);
 860                 char *demangled = NULL;
 861                 int is_label = elf_sym__is_label(&sym);
 862                 const char *section_name;
 863                 bool used_opd = false;
 864
 865                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 866                         continue;
 867
 868                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 869                  * don't identify functions, so will confuse the profile
 870                  * output: */
 871                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 872                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 873                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 874                                 continue;
 875                 }
 876
 877                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 878                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 879                         u64 *opd = opddata->d_buf + offset;
 880                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 881                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 882                                         sym.st_value);
 883                         used_opd = true;
 884                 }
 885                 /*
 886                  * When loading symbols in a data mapping, ABS symbols (which
 887                  * has a value of SHN_ABS in its st_shndx) failed at
 888                  * elf_getscn().  And it marks the loading as a failure so
 889                  * already loaded symbols cannot be fixed up.
 890                  *
 891                  * I'm not sure what should be done. Just ignore them for now.
 892                  * - Namhyung Kim
 893                  */
 894                 if (sym.st_shndx == SHN_ABS)
 895                         continue;
 896
 897                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 898                 if (!sec)
 899                         goto out_elf_end;
 900
 901                 gelf_getshdr(sec, &shdr);
 902
 903                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 904                         continue;
 905
 906                 section_name = elf_sec__name(&shdr, secstrs);
 907
 908                 /* On ARM, symbols for thumb functions have 1 added to
 909                  * the symbol address as a flag - remove it */
 910                 if ((ehdr.e_machine == EM_ARM) &&
 911                     (map->type == MAP__FUNCTION) &&
 912                     (sym.st_value & 1))
 913                         --sym.st_value;
 914
 915                 if (dso->kernel || kmodule) {
 916                         char dso_name[PATH_MAX];
 917
 918                         /* Adjust symbol to map to file offset */
 919                         if (adjust_kernel_syms)
 920                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 921
 922                         if (strcmp(section_name,
 923                                    (curr_dso->short_name +
 924                                     dso->short_name_len)) == 0)
 925                                 goto new_symbol;
 926
 927                         if (strcmp(section_name, ".text") == 0) {
 928                                 /*
 929                                  * The initial kernel mapping is based on
 930                                  * kallsyms and identity maps.  Overwrite it to
 931                                  * map to the kernel dso.
 932                                  */
 933                                 if (remap_kernel && dso->kernel) {
 934                                         remap_kernel = false;
 935                                         map->start = shdr.sh_addr +
 936                                                      ref_reloc(kmap);
 937                                         map->end = map->start + shdr.sh_size;
 938                                         map->pgoff = shdr.sh_offset;
 939                                         map->map_ip = map__map_ip;
 940                                         map->unmap_ip = map__unmap_ip;
 941                                         /* Ensure maps are correctly ordered */
 942                                         map_groups__remove(kmap->kmaps, map);
 943                                         map_groups__insert(kmap->kmaps, map);
 944                                 }
 945
 946                                 /*
 947                                  * The initial module mapping is based on
 948                                  * /proc/modules mapped to offset zero.
 949                                  * Overwrite it to map to the module dso.
 950                                  */
 951                                 if (remap_kernel && kmodule) {
 952                                         remap_kernel = false;
 953                                         map->pgoff = shdr.sh_offset;
 954                                 }
 955
 956                                 curr_map = map;
 957                                 curr_dso = dso;
 958                                 goto new_symbol;
 959                         }
 960
 961                         if (!kmap)
 962                                 goto new_symbol;
 963
 964                         snprintf(dso_name, sizeof(dso_name),
 965                                  "%s%s", dso->short_name, section_name);
 966
 967                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 968                         if (curr_map == NULL) {
 969                                 u64 start = sym.st_value;
 970
 971                                 if (kmodule)
 972                                         start += map->start + shdr.sh_offset;
 973
 974                                 curr_dso = dso__new(dso_name);
 975                                 if (curr_dso == NULL)
 976                                         goto out_elf_end;
 977                                 curr_dso->kernel = dso->kernel;
 978                                 curr_dso->long_name = dso->long_name;
 979                                 curr_dso->long_name_len = dso->long_name_len;
 980                                 curr_map = map__new2(start, curr_dso,
 981                                                      map->type);
 982                                 if (curr_map == NULL) {
 983                                         dso__delete(curr_dso);
 984                                         goto out_elf_end;
 985                                 }
 986                                 if (adjust_kernel_syms) {
 987                                         curr_map->start = shdr.sh_addr +
 988                                                           ref_reloc(kmap);
 989                                         curr_map->end = curr_map->start +
 990                                                         shdr.sh_size;
 991                                         curr_map->pgoff = shdr.sh_offset;
 992                                 } else {
 993                                         curr_map->map_ip = identity__map_ip;
 994                                         curr_map->unmap_ip = identity__map_ip;
 995                                 }
 996                                 curr_dso->symtab_type = dso->symtab_type;
 997                                 map_groups__insert(kmap->kmaps, curr_map);
 998                                 /*
 999                                  * The new DSO should go to the kernel DSOS
1000                                  */
1001                                 dsos__add(&map->groups->machine->kernel_dsos,
1002                                           curr_dso);
1003                                 dso__set_loaded(curr_dso, map->type);
1004                         } else
1005                                 curr_dso = curr_map->dso;
1006
1007                         goto new_symbol;
1008                 }
1009
1010                 if ((used_opd && runtime_ss->adjust_symbols)
1011                                 || (!used_opd && syms_ss->adjust_symbols)) {
1012                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1013                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1014                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1015                                   (u64)shdr.sh_offset);
1016                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1017                 }
1018 new_symbol:
1019                 /*
1020                  * We need to figure out if the object was created from C++ sources
1021                  * DWARF DW_compile_unit has this, but we don't always have access
1022                  * to it...
1023                  */
1024                 if (want_demangle(dso->kernel || kmodule)) {
1025                         int demangle_flags = DMGL_NO_OPTS;
1026                         if (verbose)
1027                                 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
1028
1029                         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
1030                         if (demangled != NULL)
1031                                 elf_name = demangled;
1032                 }
1033                 f = symbol__new(sym.st_value, sym.st_size,
1034                                 GELF_ST_BIND(sym.st_info), elf_name);
1035                 free(demangled);
1036                 if (!f)
1037                         goto out_elf_end;
1038
1039                 if (filter && filter(curr_map, f))
1040                         symbol__delete(f);
1041                 else {
1042                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
1043                         nr++;
1044                 }
1045         }
1046
1047         /*
1048          * For misannotated, zeroed, ASM function sizes.
1049          */
1050         if (nr > 0) {
1051                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1052                 symbols__fixup_end(&dso->symbols[map->type]);
1053                 if (kmap) {
1054                         /*
1055                          * We need to fixup this here too because we create new
1056                          * maps here, for things like vsyscall sections.
1057                          */
1058                         __map_groups__fixup_end(kmap->kmaps, map->type);
1059                 }
1060         }
1061         err = nr;
1062 out_elf_end:
1063         return err;
1064 }
1065
1066 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1067 {
1068         GElf_Phdr phdr;
1069         size_t i, phdrnum;
1070         int err;
1071         u64 sz;
1072
1073         if (elf_getphdrnum(elf, &phdrnum))
1074                 return -1;
1075
1076         for (i = 0; i < phdrnum; i++) {
1077                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1078                         return -1;
1079                 if (phdr.p_type != PT_LOAD)
1080                         continue;
1081                 if (exe) {
1082                         if (!(phdr.p_flags & PF_X))
1083                                 continue;
1084                 } else {
1085                         if (!(phdr.p_flags & PF_R))
1086                                 continue;
1087                 }
1088                 sz = min(phdr.p_memsz, phdr.p_filesz);
1089                 if (!sz)
1090                         continue;
1091                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1092                 if (err)
1093                         return err;
1094         }
1095         return 0;
1096 }
1097
1098 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1099                     bool *is_64_bit)
1100 {
1101         int err;
1102         Elf *elf;
1103
1104         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1105         if (elf == NULL)
1106                 return -1;
1107
1108         if (is_64_bit)
1109                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1110
1111         err = elf_read_maps(elf, exe, mapfn, data);
1112
1113         elf_end(elf);
1114         return err;
1115 }
1116
1117 enum dso_type dso__type_fd(int fd)
1118 {
1119         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1120         GElf_Ehdr ehdr;
1121         Elf_Kind ek;
1122         Elf *elf;
1123
1124         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1125         if (elf == NULL)
1126                 goto out;
1127
1128         ek = elf_kind(elf);
1129         if (ek != ELF_K_ELF)
1130                 goto out_end;
1131
1132         if (gelf_getclass(elf) == ELFCLASS64) {
1133                 dso_type = DSO__TYPE_64BIT;
1134                 goto out_end;
1135         }
1136
1137         if (gelf_getehdr(elf, &ehdr) == NULL)
1138                 goto out_end;
1139
1140         if (ehdr.e_machine == EM_X86_64)
1141                 dso_type = DSO__TYPE_X32BIT;
1142         else
1143                 dso_type = DSO__TYPE_32BIT;
1144 out_end:
1145         elf_end(elf);
1146 out:
1147         return dso_type;
1148 }
1149
1150 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1151 {
1152         ssize_t r;
1153         size_t n;
1154         int err = -1;
1155         char *buf = malloc(page_size);
1156
1157         if (buf == NULL)
1158                 return -1;
1159
1160         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1161                 goto out;
1162
1163         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1164                 goto out;
1165
1166         while (len) {
1167                 n = page_size;
1168                 if (len < n)
1169                         n = len;
1170                 /* Use read because mmap won't work on proc files */
1171                 r = read(from, buf, n);
1172                 if (r < 0)
1173                         goto out;
1174                 if (!r)
1175                         break;
1176                 n = r;
1177                 r = write(to, buf, n);
1178                 if (r < 0)
1179                         goto out;
1180                 if ((size_t)r != n)
1181                         goto out;
1182                 len -= n;
1183         }
1184
1185         err = 0;
1186 out:
1187         free(buf);
1188         return err;
1189 }
1190
1191 struct kcore {
1192         int fd;
1193         int elfclass;
1194         Elf *elf;
1195         GElf_Ehdr ehdr;
1196 };
1197
1198 static int kcore__open(struct kcore *kcore, const char *filename)
1199 {
1200         GElf_Ehdr *ehdr;
1201
1202         kcore->fd = open(filename, O_RDONLY);
1203         if (kcore->fd == -1)
1204                 return -1;
1205
1206         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1207         if (!kcore->elf)
1208                 goto out_close;
1209
1210         kcore->elfclass = gelf_getclass(kcore->elf);
1211         if (kcore->elfclass == ELFCLASSNONE)
1212                 goto out_end;
1213
1214         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1215         if (!ehdr)
1216                 goto out_end;
1217
1218         return 0;
1219
1220 out_end:
1221         elf_end(kcore->elf);
1222 out_close:
1223         close(kcore->fd);
1224         return -1;
1225 }
1226
1227 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1228                        bool temp)
1229 {
1230         GElf_Ehdr *ehdr;
1231
1232         kcore->elfclass = elfclass;
1233
1234         if (temp)
1235                 kcore->fd = mkstemp(filename);
1236         else
1237                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1238         if (kcore->fd == -1)
1239                 return -1;
1240
1241         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1242         if (!kcore->elf)
1243                 goto out_close;
1244
1245         if (!gelf_newehdr(kcore->elf, elfclass))
1246                 goto out_end;
1247
1248         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1249         if (!ehdr)
1250                 goto out_end;
1251
1252         return 0;
1253
1254 out_end:
1255         elf_end(kcore->elf);
1256 out_close:
1257         close(kcore->fd);
1258         unlink(filename);
1259         return -1;
1260 }
1261
1262 static void kcore__close(struct kcore *kcore)
1263 {
1264         elf_end(kcore->elf);
1265         close(kcore->fd);
1266 }
1267
1268 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1269 {
1270         GElf_Ehdr *ehdr = &to->ehdr;
1271         GElf_Ehdr *kehdr = &from->ehdr;
1272
1273         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1274         ehdr->e_type      = kehdr->e_type;
1275         ehdr->e_machine   = kehdr->e_machine;
1276         ehdr->e_version   = kehdr->e_version;
1277         ehdr->e_entry     = 0;
1278         ehdr->e_shoff     = 0;
1279         ehdr->e_flags     = kehdr->e_flags;
1280         ehdr->e_phnum     = count;
1281         ehdr->e_shentsize = 0;
1282         ehdr->e_shnum     = 0;
1283         ehdr->e_shstrndx  = 0;
1284
1285         if (from->elfclass == ELFCLASS32) {
1286                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1287                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1288                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1289         } else {
1290                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1291                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1292                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1293         }
1294
1295         if (!gelf_update_ehdr(to->elf, ehdr))
1296                 return -1;
1297
1298         if (!gelf_newphdr(to->elf, count))
1299                 return -1;
1300
1301         return 0;
1302 }
1303
1304 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1305                            u64 addr, u64 len)
1306 {
1307         GElf_Phdr gphdr;
1308         GElf_Phdr *phdr;
1309
1310         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1311         if (!phdr)
1312                 return -1;
1313
1314         phdr->p_type    = PT_LOAD;
1315         phdr->p_flags   = PF_R | PF_W | PF_X;
1316         phdr->p_offset  = offset;
1317         phdr->p_vaddr   = addr;
1318         phdr->p_paddr   = 0;
1319         phdr->p_filesz  = len;
1320         phdr->p_memsz   = len;
1321         phdr->p_align   = page_size;
1322
1323         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1324                 return -1;
1325
1326         return 0;
1327 }
1328
1329 static off_t kcore__write(struct kcore *kcore)
1330 {
1331         return elf_update(kcore->elf, ELF_C_WRITE);
1332 }
1333
1334 struct phdr_data {
1335         off_t offset;
1336         u64 addr;
1337         u64 len;
1338 };
1339
1340 struct kcore_copy_info {
1341         u64 stext;
1342         u64 etext;
1343         u64 first_symbol;
1344         u64 last_symbol;
1345         u64 first_module;
1346         u64 last_module_symbol;
1347         struct phdr_data kernel_map;
1348         struct phdr_data modules_map;
1349 };
1350
1351 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1352                                         u64 start)
1353 {
1354         struct kcore_copy_info *kci = arg;
1355
1356         if (!symbol_type__is_a(type, MAP__FUNCTION))
1357                 return 0;
1358
1359         if (strchr(name, '[')) {
1360                 if (start > kci->last_module_symbol)
1361                         kci->last_module_symbol = start;
1362                 return 0;
1363         }
1364
1365         if (!kci->first_symbol || start < kci->first_symbol)
1366                 kci->first_symbol = start;
1367
1368         if (!kci->last_symbol || start > kci->last_symbol)
1369                 kci->last_symbol = start;
1370
1371         if (!strcmp(name, "_stext")) {
1372                 kci->stext = start;
1373                 return 0;
1374         }
1375
1376         if (!strcmp(name, "_etext")) {
1377                 kci->etext = start;
1378                 return 0;
1379         }
1380
1381         return 0;
1382 }
1383
1384 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1385                                       const char *dir)
1386 {
1387         char kallsyms_filename[PATH_MAX];
1388
1389         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1390
1391         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1392                 return -1;
1393
1394         if (kallsyms__parse(kallsyms_filename, kci,
1395                             kcore_copy__process_kallsyms) < 0)
1396                 return -1;
1397
1398         return 0;
1399 }
1400
1401 static int kcore_copy__process_modules(void *arg,
1402                                        const char *name __maybe_unused,
1403                                        u64 start)
1404 {
1405         struct kcore_copy_info *kci = arg;
1406
1407         if (!kci->first_module || start < kci->first_module)
1408                 kci->first_module = start;
1409
1410         return 0;
1411 }
1412
1413 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1414                                      const char *dir)
1415 {
1416         char modules_filename[PATH_MAX];
1417
1418         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1419
1420         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1421                 return -1;
1422
1423         if (modules__parse(modules_filename, kci,
1424                            kcore_copy__process_modules) < 0)
1425                 return -1;
1426
1427         return 0;
1428 }
1429
1430 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1431                             u64 s, u64 e)
1432 {
1433         if (p->addr || s < start || s >= end)
1434                 return;
1435
1436         p->addr = s;
1437         p->offset = (s - start) + pgoff;
1438         p->len = e < end ? e - s : end - s;
1439 }
1440
1441 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1442 {
1443         struct kcore_copy_info *kci = data;
1444         u64 end = start + len;
1445
1446         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1447                         kci->etext);
1448
1449         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1450                         kci->last_module_symbol);
1451
1452         return 0;
1453 }
1454
1455 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1456 {
1457         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1458                 return -1;
1459
1460         return 0;
1461 }
1462
1463 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1464                                  Elf *elf)
1465 {
1466         if (kcore_copy__parse_kallsyms(kci, dir))
1467                 return -1;
1468
1469         if (kcore_copy__parse_modules(kci, dir))
1470                 return -1;
1471
1472         if (kci->stext)
1473                 kci->stext = round_down(kci->stext, page_size);
1474         else
1475                 kci->stext = round_down(kci->first_symbol, page_size);
1476
1477         if (kci->etext) {
1478                 kci->etext = round_up(kci->etext, page_size);
1479         } else if (kci->last_symbol) {
1480                 kci->etext = round_up(kci->last_symbol, page_size);
1481                 kci->etext += page_size;
1482         }
1483
1484         kci->first_module = round_down(kci->first_module, page_size);
1485
1486         if (kci->last_module_symbol) {
1487                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1488                                                    page_size);
1489                 kci->last_module_symbol += page_size;
1490         }
1491
1492         if (!kci->stext || !kci->etext)
1493                 return -1;
1494
1495         if (kci->first_module && !kci->last_module_symbol)
1496                 return -1;
1497
1498         return kcore_copy__read_maps(kci, elf);
1499 }
1500
1501 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1502                                  const char *name)
1503 {
1504         char from_filename[PATH_MAX];
1505         char to_filename[PATH_MAX];
1506
1507         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1508         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1509
1510         return copyfile_mode(from_filename, to_filename, 0400);
1511 }
1512
1513 static int kcore_copy__unlink(const char *dir, const char *name)
1514 {
1515         char filename[PATH_MAX];
1516
1517         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1518
1519         return unlink(filename);
1520 }
1521
1522 static int kcore_copy__compare_fds(int from, int to)
1523 {
1524         char *buf_from;
1525         char *buf_to;
1526         ssize_t ret;
1527         size_t len;
1528         int err = -1;
1529
1530         buf_from = malloc(page_size);
1531         buf_to = malloc(page_size);
1532         if (!buf_from || !buf_to)
1533                 goto out;
1534
1535         while (1) {
1536                 /* Use read because mmap won't work on proc files */
1537                 ret = read(from, buf_from, page_size);
1538                 if (ret < 0)
1539                         goto out;
1540
1541                 if (!ret)
1542                         break;
1543
1544                 len = ret;
1545
1546                 if (readn(to, buf_to, len) != (int)len)
1547                         goto out;
1548
1549                 if (memcmp(buf_from, buf_to, len))
1550                         goto out;
1551         }
1552
1553         err = 0;
1554 out:
1555         free(buf_to);
1556         free(buf_from);
1557         return err;
1558 }
1559
1560 static int kcore_copy__compare_files(const char *from_filename,
1561                                      const char *to_filename)
1562 {
1563         int from, to, err = -1;
1564
1565         from = open(from_filename, O_RDONLY);
1566         if (from < 0)
1567                 return -1;
1568
1569         to = open(to_filename, O_RDONLY);
1570         if (to < 0)
1571                 goto out_close_from;
1572
1573         err = kcore_copy__compare_fds(from, to);
1574
1575         close(to);
1576 out_close_from:
1577         close(from);
1578         return err;
1579 }
1580
1581 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1582                                     const char *name)
1583 {
1584         char from_filename[PATH_MAX];
1585         char to_filename[PATH_MAX];
1586
1587         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1588         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1589
1590         return kcore_copy__compare_files(from_filename, to_filename);
1591 }
1592
1593 /**
1594  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1595  * @from_dir: from directory
1596  * @to_dir: to directory
1597  *
1598  * This function copies kallsyms, modules and kcore files from one directory to
1599  * another.  kallsyms and modules are copied entirely.  Only code segments are
1600  * copied from kcore.  It is assumed that two segments suffice: one for the
1601  * kernel proper and one for all the modules.  The code segments are determined
1602  * from kallsyms and modules files.  The kernel map starts at _stext or the
1603  * lowest function symbol, and ends at _etext or the highest function symbol.
1604  * The module map starts at the lowest module address and ends at the highest
1605  * module symbol.  Start addresses are rounded down to the nearest page.  End
1606  * addresses are rounded up to the nearest page.  An extra page is added to the
1607  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1608  * symbol too.  Because it contains only code sections, the resulting kcore is
1609  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1610  * is not the same for the kernel map and the modules map.  That happens because
1611  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1612  * kallsyms and modules files are compared with their copies to check that
1613  * modules have not been loaded or unloaded while the copies were taking place.
1614  *
1615  * Return: %0 on success, %-1 on failure.
1616  */
1617 int kcore_copy(const char *from_dir, const char *to_dir)
1618 {
1619         struct kcore kcore;
1620         struct kcore extract;
1621         size_t count = 2;
1622         int idx = 0, err = -1;
1623         off_t offset = page_size, sz, modules_offset = 0;
1624         struct kcore_copy_info kci = { .stext = 0, };
1625         char kcore_filename[PATH_MAX];
1626         char extract_filename[PATH_MAX];
1627
1628         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1629                 return -1;
1630
1631         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1632                 goto out_unlink_kallsyms;
1633
1634         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1635         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1636
1637         if (kcore__open(&kcore, kcore_filename))
1638                 goto out_unlink_modules;
1639
1640         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1641                 goto out_kcore_close;
1642
1643         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1644                 goto out_kcore_close;
1645
1646         if (!kci.modules_map.addr)
1647                 count -= 1;
1648
1649         if (kcore__copy_hdr(&kcore, &extract, count))
1650                 goto out_extract_close;
1651
1652         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1653                             kci.kernel_map.len))
1654                 goto out_extract_close;
1655
1656         if (kci.modules_map.addr) {
1657                 modules_offset = offset + kci.kernel_map.len;
1658                 if (kcore__add_phdr(&extract, idx, modules_offset,
1659                                     kci.modules_map.addr, kci.modules_map.len))
1660                         goto out_extract_close;
1661         }
1662
1663         sz = kcore__write(&extract);
1664         if (sz < 0 || sz > offset)
1665                 goto out_extract_close;
1666
1667         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1668                        kci.kernel_map.len))
1669                 goto out_extract_close;
1670
1671         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1672                                          extract.fd, modules_offset,
1673                                          kci.modules_map.len))
1674                 goto out_extract_close;
1675
1676         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1677                 goto out_extract_close;
1678
1679         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1680                 goto out_extract_close;
1681
1682         err = 0;
1683
1684 out_extract_close:
1685         kcore__close(&extract);
1686         if (err)
1687                 unlink(extract_filename);
1688 out_kcore_close:
1689         kcore__close(&kcore);
1690 out_unlink_modules:
1691         if (err)
1692                 kcore_copy__unlink(to_dir, "modules");
1693 out_unlink_kallsyms:
1694         if (err)
1695                 kcore_copy__unlink(to_dir, "kallsyms");
1696
1697         return err;
1698 }
1699
1700 int kcore_extract__create(struct kcore_extract *kce)
1701 {
1702         struct kcore kcore;
1703         struct kcore extract;
1704         size_t count = 1;
1705         int idx = 0, err = -1;
1706         off_t offset = page_size, sz;
1707
1708         if (kcore__open(&kcore, kce->kcore_filename))
1709                 return -1;
1710
1711         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1712         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1713                 goto out_kcore_close;
1714
1715         if (kcore__copy_hdr(&kcore, &extract, count))
1716                 goto out_extract_close;
1717
1718         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1719                 goto out_extract_close;
1720
1721         sz = kcore__write(&extract);
1722         if (sz < 0 || sz > offset)
1723                 goto out_extract_close;
1724
1725         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1726                 goto out_extract_close;
1727
1728         err = 0;
1729
1730 out_extract_close:
1731         kcore__close(&extract);
1732         if (err)
1733                 unlink(kce->extract_filename);
1734 out_kcore_close:
1735         kcore__close(&kcore);
1736
1737         return err;
1738 }
1739
1740 void kcore_extract__delete(struct kcore_extract *kce)
1741 {
1742         unlink(kce->extract_filename);
1743 }
1744
1745 void symbol__elf_init(void)
1746 {
1747         elf_version(EV_CURRENT);
1748 }