tools/perf/util/symbol-elf.c

   1 #include <fcntl.h>
   2 #include <stdio.h>
   3 #include <errno.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <inttypes.h>
   7
   8 #include "symbol.h"
   9 #include "demangle-java.h"
  10 #include "demangle-rust.h"
  11 #include "machine.h"
  12 #include "vdso.h"
  13 #include <symbol/kallsyms.h>
  14 #include "debug.h"
  15
  16 #ifndef EM_AARCH64
  17 #define EM_AARCH64      183  /* ARM 64 bit */
  18 #endif
  19
  20 typedef Elf64_Nhdr GElf_Nhdr;
  21
  22 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  23 extern char *cplus_demangle(const char *, int);
  24
  25 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  26 {
  27         return cplus_demangle(c, i);
  28 }
  29 #else
  30 #ifdef NO_DEMANGLE
  31 static inline char *bfd_demangle(void __maybe_unused *v,
  32                                  const char __maybe_unused *c,
  33                                  int __maybe_unused i)
  34 {
  35         return NULL;
  36 }
  37 #else
  38 #define PACKAGE 'perf'
  39 #include <bfd.h>
  40 #endif
  41 #endif
  42
  43 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  44 static int elf_getphdrnum(Elf *elf, size_t *dst)
  45 {
  46         GElf_Ehdr gehdr;
  47         GElf_Ehdr *ehdr;
  48
  49         ehdr = gelf_getehdr(elf, &gehdr);
  50         if (!ehdr)
  51                 return -1;
  52
  53         *dst = ehdr->e_phnum;
  54
  55         return 0;
  56 }
  57 #endif
  58
  59 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  60 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  61 {
  62         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  63         return -1;
  64 }
  65 #endif
  66
  67 #ifndef NT_GNU_BUILD_ID
  68 #define NT_GNU_BUILD_ID 3
  69 #endif
  70
  71 /**
  72  * elf_symtab__for_each_symbol - iterate thru all the symbols
  73  *
  74  * @syms: struct elf_symtab instance to iterate
  75  * @idx: uint32_t idx
  76  * @sym: GElf_Sym iterator
  77  */
  78 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  79         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  80              idx < nr_syms; \
  81              idx++, gelf_getsym(syms, idx, &sym))
  82
  83 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  84 {
  85         return GELF_ST_TYPE(sym->st_info);
  86 }
  87
  88 #ifndef STT_GNU_IFUNC
  89 #define STT_GNU_IFUNC 10
  90 #endif
  91
  92 static inline int elf_sym__is_function(const GElf_Sym *sym)
  93 {
  94         return (elf_sym__type(sym) == STT_FUNC ||
  95                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  96                sym->st_name != 0 &&
  97                sym->st_shndx != SHN_UNDEF;
  98 }
  99
 100 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 101 {
 102         return elf_sym__type(sym) == STT_OBJECT &&
 103                 sym->st_name != 0 &&
 104                 sym->st_shndx != SHN_UNDEF;
 105 }
 106
 107 static inline int elf_sym__is_label(const GElf_Sym *sym)
 108 {
 109         return elf_sym__type(sym) == STT_NOTYPE &&
 110                 sym->st_name != 0 &&
 111                 sym->st_shndx != SHN_UNDEF &&
 112                 sym->st_shndx != SHN_ABS;
 113 }
 114
 115 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
 116 {
 117         switch (type) {
 118         case MAP__FUNCTION:
 119                 return elf_sym__is_function(sym);
 120         case MAP__VARIABLE:
 121                 return elf_sym__is_object(sym);
 122         default:
 123                 return false;
 124         }
 125 }
 126
 127 static inline const char *elf_sym__name(const GElf_Sym *sym,
 128                                         const Elf_Data *symstrs)
 129 {
 130         return symstrs->d_buf + sym->st_name;
 131 }
 132
 133 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 134                                         const Elf_Data *secstrs)
 135 {
 136         return secstrs->d_buf + shdr->sh_name;
 137 }
 138
 139 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 140                                         const Elf_Data *secstrs)
 141 {
 142         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 143 }
 144
 145 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 146                                     const Elf_Data *secstrs)
 147 {
 148         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 149 }
 150
 151 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 152                           enum map_type type)
 153 {
 154         switch (type) {
 155         case MAP__FUNCTION:
 156                 return elf_sec__is_text(shdr, secstrs);
 157         case MAP__VARIABLE:
 158                 return elf_sec__is_data(shdr, secstrs);
 159         default:
 160                 return false;
 161         }
 162 }
 163
 164 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 165 {
 166         Elf_Scn *sec = NULL;
 167         GElf_Shdr shdr;
 168         size_t cnt = 1;
 169
 170         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 171                 gelf_getshdr(sec, &shdr);
 172
 173                 if ((addr >= shdr.sh_addr) &&
 174                     (addr < (shdr.sh_addr + shdr.sh_size)))
 175                         return cnt;
 176
 177                 ++cnt;
 178         }
 179
 180         return -1;
 181 }
 182
 183 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 184                              GElf_Shdr *shp, const char *name, size_t *idx)
 185 {
 186         Elf_Scn *sec = NULL;
 187         size_t cnt = 1;
 188
 189         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 190         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 191                 return NULL;
 192
 193         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 194                 char *str;
 195
 196                 gelf_getshdr(sec, shp);
 197                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 198                 if (str && !strcmp(name, str)) {
 199                         if (idx)
 200                                 *idx = cnt;
 201                         return sec;
 202                 }
 203                 ++cnt;
 204         }
 205
 206         return NULL;
 207 }
 208
 209 static bool want_demangle(bool is_kernel_sym)
 210 {
 211         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 212 }
 213
 214 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 215 {
 216         int demangle_flags = verbose ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 217         char *demangled = NULL;
 218
 219         /*
 220          * We need to figure out if the object was created from C++ sources
 221          * DWARF DW_compile_unit has this, but we don't always have access
 222          * to it...
 223          */
 224         if (!want_demangle(dso->kernel || kmodule))
 225             return demangled;
 226
 227         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 228         if (demangled == NULL)
 229                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 230         else if (rust_is_mangled(demangled))
 231                 /*
 232                     * Input to Rust demangling is the BFD-demangled
 233                     * name which it Rust-demangles in place.
 234                     */
 235                 rust_demangle_sym(demangled);
 236
 237         return demangled;
 238 }
 239
 240 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 241         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 242              idx < nr_entries; \
 243              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 244
 245 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 246         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 247              idx < nr_entries; \
 248              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 249
 250 /*
 251  * We need to check if we have a .dynsym, so that we can handle the
 252  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 253  * .dynsym or .symtab).
 254  * And always look at the original dso, not at debuginfo packages, that
 255  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 256  */
 257 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
 258 {
 259         uint32_t nr_rel_entries, idx;
 260         GElf_Sym sym;
 261         u64 plt_offset;
 262         GElf_Shdr shdr_plt;
 263         struct symbol *f;
 264         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 265         Elf_Data *reldata, *syms, *symstrs;
 266         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 267         size_t dynsym_idx;
 268         GElf_Ehdr ehdr;
 269         char sympltname[1024];
 270         Elf *elf;
 271         int nr = 0, symidx, err = 0;
 272
 273         if (!ss->dynsym)
 274                 return 0;
 275
 276         elf = ss->elf;
 277         ehdr = ss->ehdr;
 278
 279         scn_dynsym = ss->dynsym;
 280         shdr_dynsym = ss->dynshdr;
 281         dynsym_idx = ss->dynsym_idx;
 282
 283         if (scn_dynsym == NULL)
 284                 goto out_elf_end;
 285
 286         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 287                                           ".rela.plt", NULL);
 288         if (scn_plt_rel == NULL) {
 289                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 290                                                   ".rel.plt", NULL);
 291                 if (scn_plt_rel == NULL)
 292                         goto out_elf_end;
 293         }
 294
 295         err = -1;
 296
 297         if (shdr_rel_plt.sh_link != dynsym_idx)
 298                 goto out_elf_end;
 299
 300         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 301                 goto out_elf_end;
 302
 303         /*
 304          * Fetch the relocation section to find the idxes to the GOT
 305          * and the symbols in the .dynsym they refer to.
 306          */
 307         reldata = elf_getdata(scn_plt_rel, NULL);
 308         if (reldata == NULL)
 309                 goto out_elf_end;
 310
 311         syms = elf_getdata(scn_dynsym, NULL);
 312         if (syms == NULL)
 313                 goto out_elf_end;
 314
 315         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 316         if (scn_symstrs == NULL)
 317                 goto out_elf_end;
 318
 319         symstrs = elf_getdata(scn_symstrs, NULL);
 320         if (symstrs == NULL)
 321                 goto out_elf_end;
 322
 323         if (symstrs->d_size == 0)
 324                 goto out_elf_end;
 325
 326         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 327         plt_offset = shdr_plt.sh_offset;
 328
 329         if (shdr_rel_plt.sh_type == SHT_RELA) {
 330                 GElf_Rela pos_mem, *pos;
 331
 332                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 333                                            nr_rel_entries) {
 334                         const char *elf_name = NULL;
 335                         char *demangled = NULL;
 336                         symidx = GELF_R_SYM(pos->r_info);
 337                         plt_offset += shdr_plt.sh_entsize;
 338                         gelf_getsym(syms, symidx, &sym);
 339
 340                         elf_name = elf_sym__name(&sym, symstrs);
 341                         demangled = demangle_sym(dso, 0, elf_name);
 342                         if (demangled != NULL)
 343                                 elf_name = demangled;
 344                         snprintf(sympltname, sizeof(sympltname),
 345                                  "%s@plt", elf_name);
 346                         free(demangled);
 347
 348                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 349                                         STB_GLOBAL, sympltname);
 350                         if (!f)
 351                                 goto out_elf_end;
 352
 353                         symbols__insert(&dso->symbols[map->type], f);
 354                         ++nr;
 355                 }
 356         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 357                 GElf_Rel pos_mem, *pos;
 358                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 359                                           nr_rel_entries) {
 360                         const char *elf_name = NULL;
 361                         char *demangled = NULL;
 362                         symidx = GELF_R_SYM(pos->r_info);
 363                         plt_offset += shdr_plt.sh_entsize;
 364                         gelf_getsym(syms, symidx, &sym);
 365
 366                         elf_name = elf_sym__name(&sym, symstrs);
 367                         demangled = demangle_sym(dso, 0, elf_name);
 368                         if (demangled != NULL)
 369                                 elf_name = demangled;
 370                         snprintf(sympltname, sizeof(sympltname),
 371                                  "%s@plt", elf_name);
 372                         free(demangled);
 373
 374                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
 375                                         STB_GLOBAL, sympltname);
 376                         if (!f)
 377                                 goto out_elf_end;
 378
 379                         symbols__insert(&dso->symbols[map->type], f);
 380                         ++nr;
 381                 }
 382         }
 383
 384         err = 0;
 385 out_elf_end:
 386         if (err == 0)
 387                 return nr;
 388         pr_debug("%s: problems reading %s PLT info.\n",
 389                  __func__, dso->long_name);
 390         return 0;
 391 }
 392
 393 /*
 394  * Align offset to 4 bytes as needed for note name and descriptor data.
 395  */
 396 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 397
 398 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 399 {
 400         int err = -1;
 401         GElf_Ehdr ehdr;
 402         GElf_Shdr shdr;
 403         Elf_Data *data;
 404         Elf_Scn *sec;
 405         Elf_Kind ek;
 406         void *ptr;
 407
 408         if (size < BUILD_ID_SIZE)
 409                 goto out;
 410
 411         ek = elf_kind(elf);
 412         if (ek != ELF_K_ELF)
 413                 goto out;
 414
 415         if (gelf_getehdr(elf, &ehdr) == NULL) {
 416                 pr_err("%s: cannot get elf header.\n", __func__);
 417                 goto out;
 418         }
 419
 420         /*
 421          * Check following sections for notes:
 422          *   '.note.gnu.build-id'
 423          *   '.notes'
 424          *   '.note' (VDSO specific)
 425          */
 426         do {
 427                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 428                                           ".note.gnu.build-id", NULL);
 429                 if (sec)
 430                         break;
 431
 432                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 433                                           ".notes", NULL);
 434                 if (sec)
 435                         break;
 436
 437                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 438                                           ".note", NULL);
 439                 if (sec)
 440                         break;
 441
 442                 return err;
 443
 444         } while (0);
 445
 446         data = elf_getdata(sec, NULL);
 447         if (data == NULL)
 448                 goto out;
 449
 450         ptr = data->d_buf;
 451         while (ptr < (data->d_buf + data->d_size)) {
 452                 GElf_Nhdr *nhdr = ptr;
 453                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 454                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 455                 const char *name;
 456
 457                 ptr += sizeof(*nhdr);
 458                 name = ptr;
 459                 ptr += namesz;
 460                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 461                     nhdr->n_namesz == sizeof("GNU")) {
 462                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 463                                 size_t sz = min(size, descsz);
 464                                 memcpy(bf, ptr, sz);
 465                                 memset(bf + sz, 0, size - sz);
 466                                 err = descsz;
 467                                 break;
 468                         }
 469                 }
 470                 ptr += descsz;
 471         }
 472
 473 out:
 474         return err;
 475 }
 476
 477 int filename__read_build_id(const char *filename, void *bf, size_t size)
 478 {
 479         int fd, err = -1;
 480         Elf *elf;
 481
 482         if (size < BUILD_ID_SIZE)
 483                 goto out;
 484
 485         fd = open(filename, O_RDONLY);
 486         if (fd < 0)
 487                 goto out;
 488
 489         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 490         if (elf == NULL) {
 491                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 492                 goto out_close;
 493         }
 494
 495         err = elf_read_build_id(elf, bf, size);
 496
 497         elf_end(elf);
 498 out_close:
 499         close(fd);
 500 out:
 501         return err;
 502 }
 503
 504 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 505 {
 506         int fd, err = -1;
 507
 508         if (size < BUILD_ID_SIZE)
 509                 goto out;
 510
 511         fd = open(filename, O_RDONLY);
 512         if (fd < 0)
 513                 goto out;
 514
 515         while (1) {
 516                 char bf[BUFSIZ];
 517                 GElf_Nhdr nhdr;
 518                 size_t namesz, descsz;
 519
 520                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 521                         break;
 522
 523                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 524                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 525                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 526                     nhdr.n_namesz == sizeof("GNU")) {
 527                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 528                                 break;
 529                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 530                                 size_t sz = min(descsz, size);
 531                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 532                                         memset(build_id + sz, 0, size - sz);
 533                                         err = 0;
 534                                         break;
 535                                 }
 536                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 537                                 break;
 538                 } else {
 539                         int n = namesz + descsz;
 540                         if (read(fd, bf, n) != n)
 541                                 break;
 542                 }
 543         }
 544         close(fd);
 545 out:
 546         return err;
 547 }
 548
 549 int filename__read_debuglink(const char *filename, char *debuglink,
 550                              size_t size)
 551 {
 552         int fd, err = -1;
 553         Elf *elf;
 554         GElf_Ehdr ehdr;
 555         GElf_Shdr shdr;
 556         Elf_Data *data;
 557         Elf_Scn *sec;
 558         Elf_Kind ek;
 559
 560         fd = open(filename, O_RDONLY);
 561         if (fd < 0)
 562                 goto out;
 563
 564         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 565         if (elf == NULL) {
 566                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 567                 goto out_close;
 568         }
 569
 570         ek = elf_kind(elf);
 571         if (ek != ELF_K_ELF)
 572                 goto out_elf_end;
 573
 574         if (gelf_getehdr(elf, &ehdr) == NULL) {
 575                 pr_err("%s: cannot get elf header.\n", __func__);
 576                 goto out_elf_end;
 577         }
 578
 579         sec = elf_section_by_name(elf, &ehdr, &shdr,
 580                                   ".gnu_debuglink", NULL);
 581         if (sec == NULL)
 582                 goto out_elf_end;
 583
 584         data = elf_getdata(sec, NULL);
 585         if (data == NULL)
 586                 goto out_elf_end;
 587
 588         /* the start of this section is a zero-terminated string */
 589         strncpy(debuglink, data->d_buf, size);
 590
 591         err = 0;
 592
 593 out_elf_end:
 594         elf_end(elf);
 595 out_close:
 596         close(fd);
 597 out:
 598         return err;
 599 }
 600
 601 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 602 {
 603         static unsigned int const endian = 1;
 604
 605         dso->needs_swap = DSO_SWAP__NO;
 606
 607         switch (eidata) {
 608         case ELFDATA2LSB:
 609                 /* We are big endian, DSO is little endian. */
 610                 if (*(unsigned char const *)&endian != 1)
 611                         dso->needs_swap = DSO_SWAP__YES;
 612                 break;
 613
 614         case ELFDATA2MSB:
 615                 /* We are little endian, DSO is big endian. */
 616                 if (*(unsigned char const *)&endian != 0)
 617                         dso->needs_swap = DSO_SWAP__YES;
 618                 break;
 619
 620         default:
 621                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 622                 return -EINVAL;
 623         }
 624
 625         return 0;
 626 }
 627
 628 static int decompress_kmodule(struct dso *dso, const char *name,
 629                               enum dso_binary_type type)
 630 {
 631         int fd = -1;
 632         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 633         struct kmod_path m;
 634
 635         if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
 636             type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
 637             type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
 638                 return -1;
 639
 640         if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
 641                 name = dso->long_name;
 642
 643         if (kmod_path__parse_ext(&m, name) || !m.comp)
 644                 return -1;
 645
 646         fd = mkstemp(tmpbuf);
 647         if (fd < 0) {
 648                 dso->load_errno = errno;
 649                 goto out;
 650         }
 651
 652         if (!decompress_to_file(m.ext, name, fd)) {
 653                 dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
 654                 close(fd);
 655                 fd = -1;
 656         }
 657
 658         unlink(tmpbuf);
 659
 660 out:
 661         free(m.ext);
 662         return fd;
 663 }
 664
 665 bool symsrc__possibly_runtime(struct symsrc *ss)
 666 {
 667         return ss->dynsym || ss->opdsec;
 668 }
 669
 670 bool symsrc__has_symtab(struct symsrc *ss)
 671 {
 672         return ss->symtab != NULL;
 673 }
 674
 675 void symsrc__destroy(struct symsrc *ss)
 676 {
 677         zfree(&ss->name);
 678         elf_end(ss->elf);
 679         close(ss->fd);
 680 }
 681
 682 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 683 {
 684         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 685 }
 686
 687 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 688                  enum dso_binary_type type)
 689 {
 690         int err = -1;
 691         GElf_Ehdr ehdr;
 692         Elf *elf;
 693         int fd;
 694
 695         if (dso__needs_decompress(dso)) {
 696                 fd = decompress_kmodule(dso, name, type);
 697                 if (fd < 0)
 698                         return -1;
 699         } else {
 700                 fd = open(name, O_RDONLY);
 701                 if (fd < 0) {
 702                         dso->load_errno = errno;
 703                         return -1;
 704                 }
 705         }
 706
 707         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 708         if (elf == NULL) {
 709                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 710                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 711                 goto out_close;
 712         }
 713
 714         if (gelf_getehdr(elf, &ehdr) == NULL) {
 715                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 716                 pr_debug("%s: cannot get elf header.\n", __func__);
 717                 goto out_elf_end;
 718         }
 719
 720         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 721                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 722                 goto out_elf_end;
 723         }
 724
 725         /* Always reject images with a mismatched build-id: */
 726         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 727                 u8 build_id[BUILD_ID_SIZE];
 728
 729                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 730                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 731                         goto out_elf_end;
 732                 }
 733
 734                 if (!dso__build_id_equal(dso, build_id)) {
 735                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 736                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 737                         goto out_elf_end;
 738                 }
 739         }
 740
 741         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 742
 743         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 744                         NULL);
 745         if (ss->symshdr.sh_type != SHT_SYMTAB)
 746                 ss->symtab = NULL;
 747
 748         ss->dynsym_idx = 0;
 749         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 750                         &ss->dynsym_idx);
 751         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 752                 ss->dynsym = NULL;
 753
 754         ss->opdidx = 0;
 755         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 756                         &ss->opdidx);
 757         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 758                 ss->opdsec = NULL;
 759
 760         if (dso->kernel == DSO_TYPE_USER)
 761                 ss->adjust_symbols = true;
 762         else
 763                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 764
 765         ss->name   = strdup(name);
 766         if (!ss->name) {
 767                 dso->load_errno = errno;
 768                 goto out_elf_end;
 769         }
 770
 771         ss->elf    = elf;
 772         ss->fd     = fd;
 773         ss->ehdr   = ehdr;
 774         ss->type   = type;
 775
 776         return 0;
 777
 778 out_elf_end:
 779         elf_end(elf);
 780 out_close:
 781         close(fd);
 782         return err;
 783 }
 784
 785 /**
 786  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 787  * @kmap: kernel maps and relocation reference symbol
 788  *
 789  * This function returns %true if we are dealing with the kernel maps and the
 790  * relocation reference symbol has not yet been found.  Otherwise %false is
 791  * returned.
 792  */
 793 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 794 {
 795         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 796                !kmap->ref_reloc_sym->unrelocated_addr;
 797 }
 798
 799 /**
 800  * ref_reloc - kernel relocation offset.
 801  * @kmap: kernel maps and relocation reference symbol
 802  *
 803  * This function returns the offset of kernel addresses as determined by using
 804  * the relocation reference symbol i.e. if the kernel has not been relocated
 805  * then the return value is zero.
 806  */
 807 static u64 ref_reloc(struct kmap *kmap)
 808 {
 809         if (kmap && kmap->ref_reloc_sym &&
 810             kmap->ref_reloc_sym->unrelocated_addr)
 811                 return kmap->ref_reloc_sym->addr -
 812                        kmap->ref_reloc_sym->unrelocated_addr;
 813         return 0;
 814 }
 815
 816 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 817                 GElf_Sym *sym __maybe_unused) { }
 818
 819 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 820                   struct symsrc *runtime_ss, int kmodule)
 821 {
 822         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 823         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 824         struct map *curr_map = map;
 825         struct dso *curr_dso = dso;
 826         Elf_Data *symstrs, *secstrs;
 827         uint32_t nr_syms;
 828         int err = -1;
 829         uint32_t idx;
 830         GElf_Ehdr ehdr;
 831         GElf_Shdr shdr;
 832         GElf_Shdr tshdr;
 833         Elf_Data *syms, *opddata = NULL;
 834         GElf_Sym sym;
 835         Elf_Scn *sec, *sec_strndx;
 836         Elf *elf;
 837         int nr = 0;
 838         bool remap_kernel = false, adjust_kernel_syms = false;
 839
 840         if (kmap && !kmaps)
 841                 return -1;
 842
 843         dso->symtab_type = syms_ss->type;
 844         dso->is_64_bit = syms_ss->is_64_bit;
 845         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 846
 847         /*
 848          * Modules may already have symbols from kallsyms, but those symbols
 849          * have the wrong values for the dso maps, so remove them.
 850          */
 851         if (kmodule && syms_ss->symtab)
 852                 symbols__delete(&dso->symbols[map->type]);
 853
 854         if (!syms_ss->symtab) {
 855                 /*
 856                  * If the vmlinux is stripped, fail so we will fall back
 857                  * to using kallsyms. The vmlinux runtime symbols aren't
 858                  * of much use.
 859                  */
 860                 if (dso->kernel)
 861                         goto out_elf_end;
 862
 863                 syms_ss->symtab  = syms_ss->dynsym;
 864                 syms_ss->symshdr = syms_ss->dynshdr;
 865         }
 866
 867         elf = syms_ss->elf;
 868         ehdr = syms_ss->ehdr;
 869         sec = syms_ss->symtab;
 870         shdr = syms_ss->symshdr;
 871
 872         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 873                                 ".text", NULL))
 874                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 875
 876         if (runtime_ss->opdsec)
 877                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 878
 879         syms = elf_getdata(sec, NULL);
 880         if (syms == NULL)
 881                 goto out_elf_end;
 882
 883         sec = elf_getscn(elf, shdr.sh_link);
 884         if (sec == NULL)
 885                 goto out_elf_end;
 886
 887         symstrs = elf_getdata(sec, NULL);
 888         if (symstrs == NULL)
 889                 goto out_elf_end;
 890
 891         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 892         if (sec_strndx == NULL)
 893                 goto out_elf_end;
 894
 895         secstrs = elf_getdata(sec_strndx, NULL);
 896         if (secstrs == NULL)
 897                 goto out_elf_end;
 898
 899         nr_syms = shdr.sh_size / shdr.sh_entsize;
 900
 901         memset(&sym, 0, sizeof(sym));
 902
 903         /*
 904          * The kernel relocation symbol is needed in advance in order to adjust
 905          * kernel maps correctly.
 906          */
 907         if (ref_reloc_sym_not_found(kmap)) {
 908                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 909                         const char *elf_name = elf_sym__name(&sym, symstrs);
 910
 911                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 912                                 continue;
 913                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 914                         map->reloc = kmap->ref_reloc_sym->addr -
 915                                      kmap->ref_reloc_sym->unrelocated_addr;
 916                         break;
 917                 }
 918         }
 919
 920         /*
 921          * Handle any relocation of vdso necessary because older kernels
 922          * attempted to prelink vdso to its virtual address.
 923          */
 924         if (dso__is_vdso(dso))
 925                 map->reloc = map->start - dso->text_offset;
 926
 927         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 928         /*
 929          * Initial kernel and module mappings do not map to the dso.  For
 930          * function mappings, flag the fixups.
 931          */
 932         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 933                 remap_kernel = true;
 934                 adjust_kernel_syms = dso->adjust_symbols;
 935         }
 936         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 937                 struct symbol *f;
 938                 const char *elf_name = elf_sym__name(&sym, symstrs);
 939                 char *demangled = NULL;
 940                 int is_label = elf_sym__is_label(&sym);
 941                 const char *section_name;
 942                 bool used_opd = false;
 943
 944                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 945                         continue;
 946
 947                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 948                  * don't identify functions, so will confuse the profile
 949                  * output: */
 950                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 951                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 952                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 953                                 continue;
 954                 }
 955
 956                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 957                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 958                         u64 *opd = opddata->d_buf + offset;
 959                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 960                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 961                                         sym.st_value);
 962                         used_opd = true;
 963                 }
 964                 /*
 965                  * When loading symbols in a data mapping, ABS symbols (which
 966                  * has a value of SHN_ABS in its st_shndx) failed at
 967                  * elf_getscn().  And it marks the loading as a failure so
 968                  * already loaded symbols cannot be fixed up.
 969                  *
 970                  * I'm not sure what should be done. Just ignore them for now.
 971                  * - Namhyung Kim
 972                  */
 973                 if (sym.st_shndx == SHN_ABS)
 974                         continue;
 975
 976                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 977                 if (!sec)
 978                         goto out_elf_end;
 979
 980                 gelf_getshdr(sec, &shdr);
 981
 982                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 983                         continue;
 984
 985                 section_name = elf_sec__name(&shdr, secstrs);
 986
 987                 /* On ARM, symbols for thumb functions have 1 added to
 988                  * the symbol address as a flag - remove it */
 989                 if ((ehdr.e_machine == EM_ARM) &&
 990                     (map->type == MAP__FUNCTION) &&
 991                     (sym.st_value & 1))
 992                         --sym.st_value;
 993
 994                 if (dso->kernel || kmodule) {
 995                         char dso_name[PATH_MAX];
 996
 997                         /* Adjust symbol to map to file offset */
 998                         if (adjust_kernel_syms)
 999                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1000
1001                         if (strcmp(section_name,
1002                                    (curr_dso->short_name +
1003                                     dso->short_name_len)) == 0)
1004                                 goto new_symbol;
1005
1006                         if (strcmp(section_name, ".text") == 0) {
1007                                 /*
1008                                  * The initial kernel mapping is based on
1009                                  * kallsyms and identity maps.  Overwrite it to
1010                                  * map to the kernel dso.
1011                                  */
1012                                 if (remap_kernel && dso->kernel) {
1013                                         remap_kernel = false;
1014                                         map->start = shdr.sh_addr +
1015                                                      ref_reloc(kmap);
1016                                         map->end = map->start + shdr.sh_size;
1017                                         map->pgoff = shdr.sh_offset;
1018                                         map->map_ip = map__map_ip;
1019                                         map->unmap_ip = map__unmap_ip;
1020                                         /* Ensure maps are correctly ordered */
1021                                         if (kmaps) {
1022                                                 map__get(map);
1023                                                 map_groups__remove(kmaps, map);
1024                                                 map_groups__insert(kmaps, map);
1025                                                 map__put(map);
1026                                         }
1027                                 }
1028
1029                                 /*
1030                                  * The initial module mapping is based on
1031                                  * /proc/modules mapped to offset zero.
1032                                  * Overwrite it to map to the module dso.
1033                                  */
1034                                 if (remap_kernel && kmodule) {
1035                                         remap_kernel = false;
1036                                         map->pgoff = shdr.sh_offset;
1037                                 }
1038
1039                                 curr_map = map;
1040                                 curr_dso = dso;
1041                                 goto new_symbol;
1042                         }
1043
1044                         if (!kmap)
1045                                 goto new_symbol;
1046
1047                         snprintf(dso_name, sizeof(dso_name),
1048                                  "%s%s", dso->short_name, section_name);
1049
1050                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1051                         if (curr_map == NULL) {
1052                                 u64 start = sym.st_value;
1053
1054                                 if (kmodule)
1055                                         start += map->start + shdr.sh_offset;
1056
1057                                 curr_dso = dso__new(dso_name);
1058                                 if (curr_dso == NULL)
1059                                         goto out_elf_end;
1060                                 curr_dso->kernel = dso->kernel;
1061                                 curr_dso->long_name = dso->long_name;
1062                                 curr_dso->long_name_len = dso->long_name_len;
1063                                 curr_map = map__new2(start, curr_dso,
1064                                                      map->type);
1065                                 dso__put(curr_dso);
1066                                 if (curr_map == NULL) {
1067                                         goto out_elf_end;
1068                                 }
1069                                 if (adjust_kernel_syms) {
1070                                         curr_map->start = shdr.sh_addr +
1071                                                           ref_reloc(kmap);
1072                                         curr_map->end = curr_map->start +
1073                                                         shdr.sh_size;
1074                                         curr_map->pgoff = shdr.sh_offset;
1075                                 } else {
1076                                         curr_map->map_ip = identity__map_ip;
1077                                         curr_map->unmap_ip = identity__map_ip;
1078                                 }
1079                                 curr_dso->symtab_type = dso->symtab_type;
1080                                 map_groups__insert(kmaps, curr_map);
1081                                 /*
1082                                  * Add it before we drop the referece to curr_map,
1083                                  * i.e. while we still are sure to have a reference
1084                                  * to this DSO via curr_map->dso.
1085                                  */
1086                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1087                                 /* kmaps already got it */
1088                                 map__put(curr_map);
1089                                 dso__set_loaded(curr_dso, map->type);
1090                         } else
1091                                 curr_dso = curr_map->dso;
1092
1093                         goto new_symbol;
1094                 }
1095
1096                 if ((used_opd && runtime_ss->adjust_symbols)
1097                                 || (!used_opd && syms_ss->adjust_symbols)) {
1098                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1099                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1100                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1101                                   (u64)shdr.sh_offset);
1102                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1103                 }
1104 new_symbol:
1105                 demangled = demangle_sym(dso, kmodule, elf_name);
1106                 if (demangled != NULL)
1107                         elf_name = demangled;
1108
1109                 f = symbol__new(sym.st_value, sym.st_size,
1110                                 GELF_ST_BIND(sym.st_info), elf_name);
1111                 free(demangled);
1112                 if (!f)
1113                         goto out_elf_end;
1114
1115                 arch__sym_update(f, &sym);
1116
1117                 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1118                 nr++;
1119         }
1120
1121         /*
1122          * For misannotated, zeroed, ASM function sizes.
1123          */
1124         if (nr > 0) {
1125                 symbols__fixup_end(&dso->symbols[map->type]);
1126                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1127                 if (kmap) {
1128                         /*
1129                          * We need to fixup this here too because we create new
1130                          * maps here, for things like vsyscall sections.
1131                          */
1132                         __map_groups__fixup_end(kmaps, map->type);
1133                 }
1134         }
1135         err = nr;
1136 out_elf_end:
1137         return err;
1138 }
1139
1140 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1141 {
1142         GElf_Phdr phdr;
1143         size_t i, phdrnum;
1144         int err;
1145         u64 sz;
1146
1147         if (elf_getphdrnum(elf, &phdrnum))
1148                 return -1;
1149
1150         for (i = 0; i < phdrnum; i++) {
1151                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1152                         return -1;
1153                 if (phdr.p_type != PT_LOAD)
1154                         continue;
1155                 if (exe) {
1156                         if (!(phdr.p_flags & PF_X))
1157                                 continue;
1158                 } else {
1159                         if (!(phdr.p_flags & PF_R))
1160                                 continue;
1161                 }
1162                 sz = min(phdr.p_memsz, phdr.p_filesz);
1163                 if (!sz)
1164                         continue;
1165                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1166                 if (err)
1167                         return err;
1168         }
1169         return 0;
1170 }
1171
1172 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1173                     bool *is_64_bit)
1174 {
1175         int err;
1176         Elf *elf;
1177
1178         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1179         if (elf == NULL)
1180                 return -1;
1181
1182         if (is_64_bit)
1183                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1184
1185         err = elf_read_maps(elf, exe, mapfn, data);
1186
1187         elf_end(elf);
1188         return err;
1189 }
1190
1191 enum dso_type dso__type_fd(int fd)
1192 {
1193         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1194         GElf_Ehdr ehdr;
1195         Elf_Kind ek;
1196         Elf *elf;
1197
1198         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1199         if (elf == NULL)
1200                 goto out;
1201
1202         ek = elf_kind(elf);
1203         if (ek != ELF_K_ELF)
1204                 goto out_end;
1205
1206         if (gelf_getclass(elf) == ELFCLASS64) {
1207                 dso_type = DSO__TYPE_64BIT;
1208                 goto out_end;
1209         }
1210
1211         if (gelf_getehdr(elf, &ehdr) == NULL)
1212                 goto out_end;
1213
1214         if (ehdr.e_machine == EM_X86_64)
1215                 dso_type = DSO__TYPE_X32BIT;
1216         else
1217                 dso_type = DSO__TYPE_32BIT;
1218 out_end:
1219         elf_end(elf);
1220 out:
1221         return dso_type;
1222 }
1223
1224 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1225 {
1226         ssize_t r;
1227         size_t n;
1228         int err = -1;
1229         char *buf = malloc(page_size);
1230
1231         if (buf == NULL)
1232                 return -1;
1233
1234         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1235                 goto out;
1236
1237         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1238                 goto out;
1239
1240         while (len) {
1241                 n = page_size;
1242                 if (len < n)
1243                         n = len;
1244                 /* Use read because mmap won't work on proc files */
1245                 r = read(from, buf, n);
1246                 if (r < 0)
1247                         goto out;
1248                 if (!r)
1249                         break;
1250                 n = r;
1251                 r = write(to, buf, n);
1252                 if (r < 0)
1253                         goto out;
1254                 if ((size_t)r != n)
1255                         goto out;
1256                 len -= n;
1257         }
1258
1259         err = 0;
1260 out:
1261         free(buf);
1262         return err;
1263 }
1264
1265 struct kcore {
1266         int fd;
1267         int elfclass;
1268         Elf *elf;
1269         GElf_Ehdr ehdr;
1270 };
1271
1272 static int kcore__open(struct kcore *kcore, const char *filename)
1273 {
1274         GElf_Ehdr *ehdr;
1275
1276         kcore->fd = open(filename, O_RDONLY);
1277         if (kcore->fd == -1)
1278                 return -1;
1279
1280         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1281         if (!kcore->elf)
1282                 goto out_close;
1283
1284         kcore->elfclass = gelf_getclass(kcore->elf);
1285         if (kcore->elfclass == ELFCLASSNONE)
1286                 goto out_end;
1287
1288         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1289         if (!ehdr)
1290                 goto out_end;
1291
1292         return 0;
1293
1294 out_end:
1295         elf_end(kcore->elf);
1296 out_close:
1297         close(kcore->fd);
1298         return -1;
1299 }
1300
1301 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1302                        bool temp)
1303 {
1304         kcore->elfclass = elfclass;
1305
1306         if (temp)
1307                 kcore->fd = mkstemp(filename);
1308         else
1309                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1310         if (kcore->fd == -1)
1311                 return -1;
1312
1313         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1314         if (!kcore->elf)
1315                 goto out_close;
1316
1317         if (!gelf_newehdr(kcore->elf, elfclass))
1318                 goto out_end;
1319
1320         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1321
1322         return 0;
1323
1324 out_end:
1325         elf_end(kcore->elf);
1326 out_close:
1327         close(kcore->fd);
1328         unlink(filename);
1329         return -1;
1330 }
1331
1332 static void kcore__close(struct kcore *kcore)
1333 {
1334         elf_end(kcore->elf);
1335         close(kcore->fd);
1336 }
1337
1338 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1339 {
1340         GElf_Ehdr *ehdr = &to->ehdr;
1341         GElf_Ehdr *kehdr = &from->ehdr;
1342
1343         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1344         ehdr->e_type      = kehdr->e_type;
1345         ehdr->e_machine   = kehdr->e_machine;
1346         ehdr->e_version   = kehdr->e_version;
1347         ehdr->e_entry     = 0;
1348         ehdr->e_shoff     = 0;
1349         ehdr->e_flags     = kehdr->e_flags;
1350         ehdr->e_phnum     = count;
1351         ehdr->e_shentsize = 0;
1352         ehdr->e_shnum     = 0;
1353         ehdr->e_shstrndx  = 0;
1354
1355         if (from->elfclass == ELFCLASS32) {
1356                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1357                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1358                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1359         } else {
1360                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1361                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1362                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1363         }
1364
1365         if (!gelf_update_ehdr(to->elf, ehdr))
1366                 return -1;
1367
1368         if (!gelf_newphdr(to->elf, count))
1369                 return -1;
1370
1371         return 0;
1372 }
1373
1374 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1375                            u64 addr, u64 len)
1376 {
1377         GElf_Phdr phdr = {
1378                 .p_type         = PT_LOAD,
1379                 .p_flags        = PF_R | PF_W | PF_X,
1380                 .p_offset       = offset,
1381                 .p_vaddr        = addr,
1382                 .p_paddr        = 0,
1383                 .p_filesz       = len,
1384                 .p_memsz        = len,
1385                 .p_align        = page_size,
1386         };
1387
1388         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1389                 return -1;
1390
1391         return 0;
1392 }
1393
1394 static off_t kcore__write(struct kcore *kcore)
1395 {
1396         return elf_update(kcore->elf, ELF_C_WRITE);
1397 }
1398
1399 struct phdr_data {
1400         off_t offset;
1401         u64 addr;
1402         u64 len;
1403 };
1404
1405 struct kcore_copy_info {
1406         u64 stext;
1407         u64 etext;
1408         u64 first_symbol;
1409         u64 last_symbol;
1410         u64 first_module;
1411         u64 last_module_symbol;
1412         struct phdr_data kernel_map;
1413         struct phdr_data modules_map;
1414 };
1415
1416 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1417                                         u64 start)
1418 {
1419         struct kcore_copy_info *kci = arg;
1420
1421         if (!symbol_type__is_a(type, MAP__FUNCTION))
1422                 return 0;
1423
1424         if (strchr(name, '[')) {
1425                 if (start > kci->last_module_symbol)
1426                         kci->last_module_symbol = start;
1427                 return 0;
1428         }
1429
1430         if (!kci->first_symbol || start < kci->first_symbol)
1431                 kci->first_symbol = start;
1432
1433         if (!kci->last_symbol || start > kci->last_symbol)
1434                 kci->last_symbol = start;
1435
1436         if (!strcmp(name, "_stext")) {
1437                 kci->stext = start;
1438                 return 0;
1439         }
1440
1441         if (!strcmp(name, "_etext")) {
1442                 kci->etext = start;
1443                 return 0;
1444         }
1445
1446         return 0;
1447 }
1448
1449 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1450                                       const char *dir)
1451 {
1452         char kallsyms_filename[PATH_MAX];
1453
1454         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1455
1456         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1457                 return -1;
1458
1459         if (kallsyms__parse(kallsyms_filename, kci,
1460                             kcore_copy__process_kallsyms) < 0)
1461                 return -1;
1462
1463         return 0;
1464 }
1465
1466 static int kcore_copy__process_modules(void *arg,
1467                                        const char *name __maybe_unused,
1468                                        u64 start)
1469 {
1470         struct kcore_copy_info *kci = arg;
1471
1472         if (!kci->first_module || start < kci->first_module)
1473                 kci->first_module = start;
1474
1475         return 0;
1476 }
1477
1478 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1479                                      const char *dir)
1480 {
1481         char modules_filename[PATH_MAX];
1482
1483         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1484
1485         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1486                 return -1;
1487
1488         if (modules__parse(modules_filename, kci,
1489                            kcore_copy__process_modules) < 0)
1490                 return -1;
1491
1492         return 0;
1493 }
1494
1495 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1496                             u64 s, u64 e)
1497 {
1498         if (p->addr || s < start || s >= end)
1499                 return;
1500
1501         p->addr = s;
1502         p->offset = (s - start) + pgoff;
1503         p->len = e < end ? e - s : end - s;
1504 }
1505
1506 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1507 {
1508         struct kcore_copy_info *kci = data;
1509         u64 end = start + len;
1510
1511         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1512                         kci->etext);
1513
1514         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1515                         kci->last_module_symbol);
1516
1517         return 0;
1518 }
1519
1520 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1521 {
1522         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1523                 return -1;
1524
1525         return 0;
1526 }
1527
1528 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1529                                  Elf *elf)
1530 {
1531         if (kcore_copy__parse_kallsyms(kci, dir))
1532                 return -1;
1533
1534         if (kcore_copy__parse_modules(kci, dir))
1535                 return -1;
1536
1537         if (kci->stext)
1538                 kci->stext = round_down(kci->stext, page_size);
1539         else
1540                 kci->stext = round_down(kci->first_symbol, page_size);
1541
1542         if (kci->etext) {
1543                 kci->etext = round_up(kci->etext, page_size);
1544         } else if (kci->last_symbol) {
1545                 kci->etext = round_up(kci->last_symbol, page_size);
1546                 kci->etext += page_size;
1547         }
1548
1549         kci->first_module = round_down(kci->first_module, page_size);
1550
1551         if (kci->last_module_symbol) {
1552                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1553                                                    page_size);
1554                 kci->last_module_symbol += page_size;
1555         }
1556
1557         if (!kci->stext || !kci->etext)
1558                 return -1;
1559
1560         if (kci->first_module && !kci->last_module_symbol)
1561                 return -1;
1562
1563         return kcore_copy__read_maps(kci, elf);
1564 }
1565
1566 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1567                                  const char *name)
1568 {
1569         char from_filename[PATH_MAX];
1570         char to_filename[PATH_MAX];
1571
1572         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1573         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1574
1575         return copyfile_mode(from_filename, to_filename, 0400);
1576 }
1577
1578 static int kcore_copy__unlink(const char *dir, const char *name)
1579 {
1580         char filename[PATH_MAX];
1581
1582         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1583
1584         return unlink(filename);
1585 }
1586
1587 static int kcore_copy__compare_fds(int from, int to)
1588 {
1589         char *buf_from;
1590         char *buf_to;
1591         ssize_t ret;
1592         size_t len;
1593         int err = -1;
1594
1595         buf_from = malloc(page_size);
1596         buf_to = malloc(page_size);
1597         if (!buf_from || !buf_to)
1598                 goto out;
1599
1600         while (1) {
1601                 /* Use read because mmap won't work on proc files */
1602                 ret = read(from, buf_from, page_size);
1603                 if (ret < 0)
1604                         goto out;
1605
1606                 if (!ret)
1607                         break;
1608
1609                 len = ret;
1610
1611                 if (readn(to, buf_to, len) != (int)len)
1612                         goto out;
1613
1614                 if (memcmp(buf_from, buf_to, len))
1615                         goto out;
1616         }
1617
1618         err = 0;
1619 out:
1620         free(buf_to);
1621         free(buf_from);
1622         return err;
1623 }
1624
1625 static int kcore_copy__compare_files(const char *from_filename,
1626                                      const char *to_filename)
1627 {
1628         int from, to, err = -1;
1629
1630         from = open(from_filename, O_RDONLY);
1631         if (from < 0)
1632                 return -1;
1633
1634         to = open(to_filename, O_RDONLY);
1635         if (to < 0)
1636                 goto out_close_from;
1637
1638         err = kcore_copy__compare_fds(from, to);
1639
1640         close(to);
1641 out_close_from:
1642         close(from);
1643         return err;
1644 }
1645
1646 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1647                                     const char *name)
1648 {
1649         char from_filename[PATH_MAX];
1650         char to_filename[PATH_MAX];
1651
1652         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1653         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1654
1655         return kcore_copy__compare_files(from_filename, to_filename);
1656 }
1657
1658 /**
1659  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1660  * @from_dir: from directory
1661  * @to_dir: to directory
1662  *
1663  * This function copies kallsyms, modules and kcore files from one directory to
1664  * another.  kallsyms and modules are copied entirely.  Only code segments are
1665  * copied from kcore.  It is assumed that two segments suffice: one for the
1666  * kernel proper and one for all the modules.  The code segments are determined
1667  * from kallsyms and modules files.  The kernel map starts at _stext or the
1668  * lowest function symbol, and ends at _etext or the highest function symbol.
1669  * The module map starts at the lowest module address and ends at the highest
1670  * module symbol.  Start addresses are rounded down to the nearest page.  End
1671  * addresses are rounded up to the nearest page.  An extra page is added to the
1672  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1673  * symbol too.  Because it contains only code sections, the resulting kcore is
1674  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1675  * is not the same for the kernel map and the modules map.  That happens because
1676  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1677  * kallsyms and modules files are compared with their copies to check that
1678  * modules have not been loaded or unloaded while the copies were taking place.
1679  *
1680  * Return: %0 on success, %-1 on failure.
1681  */
1682 int kcore_copy(const char *from_dir, const char *to_dir)
1683 {
1684         struct kcore kcore;
1685         struct kcore extract;
1686         size_t count = 2;
1687         int idx = 0, err = -1;
1688         off_t offset = page_size, sz, modules_offset = 0;
1689         struct kcore_copy_info kci = { .stext = 0, };
1690         char kcore_filename[PATH_MAX];
1691         char extract_filename[PATH_MAX];
1692
1693         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1694                 return -1;
1695
1696         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1697                 goto out_unlink_kallsyms;
1698
1699         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1700         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1701
1702         if (kcore__open(&kcore, kcore_filename))
1703                 goto out_unlink_modules;
1704
1705         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1706                 goto out_kcore_close;
1707
1708         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1709                 goto out_kcore_close;
1710
1711         if (!kci.modules_map.addr)
1712                 count -= 1;
1713
1714         if (kcore__copy_hdr(&kcore, &extract, count))
1715                 goto out_extract_close;
1716
1717         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1718                             kci.kernel_map.len))
1719                 goto out_extract_close;
1720
1721         if (kci.modules_map.addr) {
1722                 modules_offset = offset + kci.kernel_map.len;
1723                 if (kcore__add_phdr(&extract, idx, modules_offset,
1724                                     kci.modules_map.addr, kci.modules_map.len))
1725                         goto out_extract_close;
1726         }
1727
1728         sz = kcore__write(&extract);
1729         if (sz < 0 || sz > offset)
1730                 goto out_extract_close;
1731
1732         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1733                        kci.kernel_map.len))
1734                 goto out_extract_close;
1735
1736         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1737                                          extract.fd, modules_offset,
1738                                          kci.modules_map.len))
1739                 goto out_extract_close;
1740
1741         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1742                 goto out_extract_close;
1743
1744         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1745                 goto out_extract_close;
1746
1747         err = 0;
1748
1749 out_extract_close:
1750         kcore__close(&extract);
1751         if (err)
1752                 unlink(extract_filename);
1753 out_kcore_close:
1754         kcore__close(&kcore);
1755 out_unlink_modules:
1756         if (err)
1757                 kcore_copy__unlink(to_dir, "modules");
1758 out_unlink_kallsyms:
1759         if (err)
1760                 kcore_copy__unlink(to_dir, "kallsyms");
1761
1762         return err;
1763 }
1764
1765 int kcore_extract__create(struct kcore_extract *kce)
1766 {
1767         struct kcore kcore;
1768         struct kcore extract;
1769         size_t count = 1;
1770         int idx = 0, err = -1;
1771         off_t offset = page_size, sz;
1772
1773         if (kcore__open(&kcore, kce->kcore_filename))
1774                 return -1;
1775
1776         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1777         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1778                 goto out_kcore_close;
1779
1780         if (kcore__copy_hdr(&kcore, &extract, count))
1781                 goto out_extract_close;
1782
1783         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1784                 goto out_extract_close;
1785
1786         sz = kcore__write(&extract);
1787         if (sz < 0 || sz > offset)
1788                 goto out_extract_close;
1789
1790         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1791                 goto out_extract_close;
1792
1793         err = 0;
1794
1795 out_extract_close:
1796         kcore__close(&extract);
1797         if (err)
1798                 unlink(kce->extract_filename);
1799 out_kcore_close:
1800         kcore__close(&kcore);
1801
1802         return err;
1803 }
1804
1805 void kcore_extract__delete(struct kcore_extract *kce)
1806 {
1807         unlink(kce->extract_filename);
1808 }
1809
1810 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1811 /**
1812  * populate_sdt_note : Parse raw data and identify SDT note
1813  * @elf: elf of the opened file
1814  * @data: raw data of a section with description offset applied
1815  * @len: note description size
1816  * @type: type of the note
1817  * @sdt_notes: List to add the SDT note
1818  *
1819  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1820  * if its an SDT note, it appends to @sdt_notes list.
1821  */
1822 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1823                              struct list_head *sdt_notes)
1824 {
1825         const char *provider, *name;
1826         struct sdt_note *tmp = NULL;
1827         GElf_Ehdr ehdr;
1828         GElf_Addr base_off = 0;
1829         GElf_Shdr shdr;
1830         int ret = -EINVAL;
1831
1832         union {
1833                 Elf64_Addr a64[NR_ADDR];
1834                 Elf32_Addr a32[NR_ADDR];
1835         } buf;
1836
1837         Elf_Data dst = {
1838                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1839                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1840                 .d_off = 0, .d_align = 0
1841         };
1842         Elf_Data src = {
1843                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1844                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1845                 .d_align = 0
1846         };
1847
1848         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1849         if (!tmp) {
1850                 ret = -ENOMEM;
1851                 goto out_err;
1852         }
1853
1854         INIT_LIST_HEAD(&tmp->note_list);
1855
1856         if (len < dst.d_size + 3)
1857                 goto out_free_note;
1858
1859         /* Translation from file representation to memory representation */
1860         if (gelf_xlatetom(*elf, &dst, &src,
1861                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1862                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1863                 goto out_free_note;
1864         }
1865
1866         /* Populate the fields of sdt_note */
1867         provider = data + dst.d_size;
1868
1869         name = (const char *)memchr(provider, '\0', data + len - provider);
1870         if (name++ == NULL)
1871                 goto out_free_note;
1872
1873         tmp->provider = strdup(provider);
1874         if (!tmp->provider) {
1875                 ret = -ENOMEM;
1876                 goto out_free_note;
1877         }
1878         tmp->name = strdup(name);
1879         if (!tmp->name) {
1880                 ret = -ENOMEM;
1881                 goto out_free_prov;
1882         }
1883
1884         if (gelf_getclass(*elf) == ELFCLASS32) {
1885                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1886                 tmp->bit32 = true;
1887         } else {
1888                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1889                 tmp->bit32 = false;
1890         }
1891
1892         if (!gelf_getehdr(*elf, &ehdr)) {
1893                 pr_debug("%s : cannot get elf header.\n", __func__);
1894                 ret = -EBADF;
1895                 goto out_free_name;
1896         }
1897
1898         /* Adjust the prelink effect :
1899          * Find out the .stapsdt.base section.
1900          * This scn will help us to handle prelinking (if present).
1901          * Compare the retrieved file offset of the base section with the
1902          * base address in the description of the SDT note. If its different,
1903          * then accordingly, adjust the note location.
1904          */
1905         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1906                 base_off = shdr.sh_offset;
1907                 if (base_off) {
1908                         if (tmp->bit32)
1909                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1910                                         tmp->addr.a32[1];
1911                         else
1912                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1913                                         tmp->addr.a64[1];
1914                 }
1915         }
1916
1917         list_add_tail(&tmp->note_list, sdt_notes);
1918         return 0;
1919
1920 out_free_name:
1921         free(tmp->name);
1922 out_free_prov:
1923         free(tmp->provider);
1924 out_free_note:
1925         free(tmp);
1926 out_err:
1927         return ret;
1928 }
1929
1930 /**
1931  * construct_sdt_notes_list : constructs a list of SDT notes
1932  * @elf : elf to look into
1933  * @sdt_notes : empty list_head
1934  *
1935  * Scans the sections in 'elf' for the section
1936  * .note.stapsdt. It, then calls populate_sdt_note to find
1937  * out the SDT events and populates the 'sdt_notes'.
1938  */
1939 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1940 {
1941         GElf_Ehdr ehdr;
1942         Elf_Scn *scn = NULL;
1943         Elf_Data *data;
1944         GElf_Shdr shdr;
1945         size_t shstrndx, next;
1946         GElf_Nhdr nhdr;
1947         size_t name_off, desc_off, offset;
1948         int ret = 0;
1949
1950         if (gelf_getehdr(elf, &ehdr) == NULL) {
1951                 ret = -EBADF;
1952                 goto out_ret;
1953         }
1954         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1955                 ret = -EBADF;
1956                 goto out_ret;
1957         }
1958
1959         /* Look for the required section */
1960         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1961         if (!scn) {
1962                 ret = -ENOENT;
1963                 goto out_ret;
1964         }
1965
1966         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1967                 ret = -ENOENT;
1968                 goto out_ret;
1969         }
1970
1971         data = elf_getdata(scn, NULL);
1972
1973         /* Get the SDT notes */
1974         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1975                                               &desc_off)) > 0; offset = next) {
1976                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1977                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1978                             sizeof(SDT_NOTE_NAME))) {
1979                         /* Check the type of the note */
1980                         if (nhdr.n_type != SDT_NOTE_TYPE)
1981                                 goto out_ret;
1982
1983                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
1984                                                 nhdr.n_descsz, sdt_notes);
1985                         if (ret < 0)
1986                                 goto out_ret;
1987                 }
1988         }
1989         if (list_empty(sdt_notes))
1990                 ret = -ENOENT;
1991
1992 out_ret:
1993         return ret;
1994 }
1995
1996 /**
1997  * get_sdt_note_list : Wrapper to construct a list of sdt notes
1998  * @head : empty list_head
1999  * @target : file to find SDT notes from
2000  *
2001  * This opens the file, initializes
2002  * the ELF and then calls construct_sdt_notes_list.
2003  */
2004 int get_sdt_note_list(struct list_head *head, const char *target)
2005 {
2006         Elf *elf;
2007         int fd, ret;
2008
2009         fd = open(target, O_RDONLY);
2010         if (fd < 0)
2011                 return -EBADF;
2012
2013         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2014         if (!elf) {
2015                 ret = -EBADF;
2016                 goto out_close;
2017         }
2018         ret = construct_sdt_notes_list(elf, head);
2019         elf_end(elf);
2020 out_close:
2021         close(fd);
2022         return ret;
2023 }
2024
2025 /**
2026  * cleanup_sdt_note_list : free the sdt notes' list
2027  * @sdt_notes: sdt notes' list
2028  *
2029  * Free up the SDT notes in @sdt_notes.
2030  * Returns the number of SDT notes free'd.
2031  */
2032 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2033 {
2034         struct sdt_note *tmp, *pos;
2035         int nr_free = 0;
2036
2037         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2038                 list_del(&pos->note_list);
2039                 free(pos->name);
2040                 free(pos->provider);
2041                 free(pos);
2042                 nr_free++;
2043         }
2044         return nr_free;
2045 }
2046
2047 /**
2048  * sdt_notes__get_count: Counts the number of sdt events
2049  * @start: list_head to sdt_notes list
2050  *
2051  * Returns the number of SDT notes in a list
2052  */
2053 int sdt_notes__get_count(struct list_head *start)
2054 {
2055         struct sdt_note *sdt_ptr;
2056         int count = 0;
2057
2058         list_for_each_entry(sdt_ptr, start, note_list)
2059                 count++;
2060         return count;
2061 }
2062 #endif
2063
2064 void symbol__elf_init(void)
2065 {
2066         elf_version(EV_CURRENT);
2067 }