tools/perf/util/symbol-elf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <inttypes.h>
   8
   9 #include "symbol.h"
  10 #include "demangle-java.h"
  11 #include "demangle-rust.h"
  12 #include "machine.h"
  13 #include "vdso.h"
  14 #include "debug.h"
  15 #include "sane_ctype.h"
  16 #include <symbol/kallsyms.h>
  17
  18 #ifndef EM_AARCH64
  19 #define EM_AARCH64      183  /* ARM 64 bit */
  20 #endif
  21
  22 typedef Elf64_Nhdr GElf_Nhdr;
  23
  24 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  25 extern char *cplus_demangle(const char *, int);
  26
  27 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  28 {
  29         return cplus_demangle(c, i);
  30 }
  31 #else
  32 #ifdef NO_DEMANGLE
  33 static inline char *bfd_demangle(void __maybe_unused *v,
  34                                  const char __maybe_unused *c,
  35                                  int __maybe_unused i)
  36 {
  37         return NULL;
  38 }
  39 #else
  40 #define PACKAGE 'perf'
  41 #include <bfd.h>
  42 #endif
  43 #endif
  44
  45 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  46 static int elf_getphdrnum(Elf *elf, size_t *dst)
  47 {
  48         GElf_Ehdr gehdr;
  49         GElf_Ehdr *ehdr;
  50
  51         ehdr = gelf_getehdr(elf, &gehdr);
  52         if (!ehdr)
  53                 return -1;
  54
  55         *dst = ehdr->e_phnum;
  56
  57         return 0;
  58 }
  59 #endif
  60
  61 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  62 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  63 {
  64         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  65         return -1;
  66 }
  67 #endif
  68
  69 #ifndef NT_GNU_BUILD_ID
  70 #define NT_GNU_BUILD_ID 3
  71 #endif
  72
  73 /**
  74  * elf_symtab__for_each_symbol - iterate thru all the symbols
  75  *
  76  * @syms: struct elf_symtab instance to iterate
  77  * @idx: uint32_t idx
  78  * @sym: GElf_Sym iterator
  79  */
  80 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
  81         for (idx = 0, gelf_getsym(syms, idx, &sym);\
  82              idx < nr_syms; \
  83              idx++, gelf_getsym(syms, idx, &sym))
  84
  85 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
  86 {
  87         return GELF_ST_TYPE(sym->st_info);
  88 }
  89
  90 #ifndef STT_GNU_IFUNC
  91 #define STT_GNU_IFUNC 10
  92 #endif
  93
  94 static inline int elf_sym__is_function(const GElf_Sym *sym)
  95 {
  96         return (elf_sym__type(sym) == STT_FUNC ||
  97                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
  98                sym->st_name != 0 &&
  99                sym->st_shndx != SHN_UNDEF;
 100 }
 101
 102 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 103 {
 104         return elf_sym__type(sym) == STT_OBJECT &&
 105                 sym->st_name != 0 &&
 106                 sym->st_shndx != SHN_UNDEF;
 107 }
 108
 109 static inline int elf_sym__is_label(const GElf_Sym *sym)
 110 {
 111         return elf_sym__type(sym) == STT_NOTYPE &&
 112                 sym->st_name != 0 &&
 113                 sym->st_shndx != SHN_UNDEF &&
 114                 sym->st_shndx != SHN_ABS;
 115 }
 116
 117 static bool elf_sym__filter(GElf_Sym *sym)
 118 {
 119         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 120 }
 121
 122 static inline const char *elf_sym__name(const GElf_Sym *sym,
 123                                         const Elf_Data *symstrs)
 124 {
 125         return symstrs->d_buf + sym->st_name;
 126 }
 127
 128 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 129                                         const Elf_Data *secstrs)
 130 {
 131         return secstrs->d_buf + shdr->sh_name;
 132 }
 133
 134 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 135                                         const Elf_Data *secstrs)
 136 {
 137         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 138 }
 139
 140 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 141                                     const Elf_Data *secstrs)
 142 {
 143         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 144 }
 145
 146 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 147 {
 148         return elf_sec__is_text(shdr, secstrs) ||
 149                elf_sec__is_data(shdr, secstrs);
 150 }
 151
 152 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 153 {
 154         Elf_Scn *sec = NULL;
 155         GElf_Shdr shdr;
 156         size_t cnt = 1;
 157
 158         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 159                 gelf_getshdr(sec, &shdr);
 160
 161                 if ((addr >= shdr.sh_addr) &&
 162                     (addr < (shdr.sh_addr + shdr.sh_size)))
 163                         return cnt;
 164
 165                 ++cnt;
 166         }
 167
 168         return -1;
 169 }
 170
 171 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 172                              GElf_Shdr *shp, const char *name, size_t *idx)
 173 {
 174         Elf_Scn *sec = NULL;
 175         size_t cnt = 1;
 176
 177         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 178         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 179                 return NULL;
 180
 181         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 182                 char *str;
 183
 184                 gelf_getshdr(sec, shp);
 185                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 186                 if (str && !strcmp(name, str)) {
 187                         if (idx)
 188                                 *idx = cnt;
 189                         return sec;
 190                 }
 191                 ++cnt;
 192         }
 193
 194         return NULL;
 195 }
 196
 197 static bool want_demangle(bool is_kernel_sym)
 198 {
 199         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 200 }
 201
 202 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 203 {
 204         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 205         char *demangled = NULL;
 206
 207         /*
 208          * We need to figure out if the object was created from C++ sources
 209          * DWARF DW_compile_unit has this, but we don't always have access
 210          * to it...
 211          */
 212         if (!want_demangle(dso->kernel || kmodule))
 213             return demangled;
 214
 215         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 216         if (demangled == NULL)
 217                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 218         else if (rust_is_mangled(demangled))
 219                 /*
 220                     * Input to Rust demangling is the BFD-demangled
 221                     * name which it Rust-demangles in place.
 222                     */
 223                 rust_demangle_sym(demangled);
 224
 225         return demangled;
 226 }
 227
 228 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 229         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 230              idx < nr_entries; \
 231              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 232
 233 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 234         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 235              idx < nr_entries; \
 236              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 237
 238 /*
 239  * We need to check if we have a .dynsym, so that we can handle the
 240  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 241  * .dynsym or .symtab).
 242  * And always look at the original dso, not at debuginfo packages, that
 243  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 244  */
 245 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 246 {
 247         uint32_t nr_rel_entries, idx;
 248         GElf_Sym sym;
 249         u64 plt_offset, plt_header_size, plt_entry_size;
 250         GElf_Shdr shdr_plt;
 251         struct symbol *f;
 252         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 253         Elf_Data *reldata, *syms, *symstrs;
 254         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 255         size_t dynsym_idx;
 256         GElf_Ehdr ehdr;
 257         char sympltname[1024];
 258         Elf *elf;
 259         int nr = 0, symidx, err = 0;
 260
 261         if (!ss->dynsym)
 262                 return 0;
 263
 264         elf = ss->elf;
 265         ehdr = ss->ehdr;
 266
 267         scn_dynsym = ss->dynsym;
 268         shdr_dynsym = ss->dynshdr;
 269         dynsym_idx = ss->dynsym_idx;
 270
 271         if (scn_dynsym == NULL)
 272                 goto out_elf_end;
 273
 274         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 275                                           ".rela.plt", NULL);
 276         if (scn_plt_rel == NULL) {
 277                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 278                                                   ".rel.plt", NULL);
 279                 if (scn_plt_rel == NULL)
 280                         goto out_elf_end;
 281         }
 282
 283         err = -1;
 284
 285         if (shdr_rel_plt.sh_link != dynsym_idx)
 286                 goto out_elf_end;
 287
 288         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 289                 goto out_elf_end;
 290
 291         /*
 292          * Fetch the relocation section to find the idxes to the GOT
 293          * and the symbols in the .dynsym they refer to.
 294          */
 295         reldata = elf_getdata(scn_plt_rel, NULL);
 296         if (reldata == NULL)
 297                 goto out_elf_end;
 298
 299         syms = elf_getdata(scn_dynsym, NULL);
 300         if (syms == NULL)
 301                 goto out_elf_end;
 302
 303         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 304         if (scn_symstrs == NULL)
 305                 goto out_elf_end;
 306
 307         symstrs = elf_getdata(scn_symstrs, NULL);
 308         if (symstrs == NULL)
 309                 goto out_elf_end;
 310
 311         if (symstrs->d_size == 0)
 312                 goto out_elf_end;
 313
 314         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 315         plt_offset = shdr_plt.sh_offset;
 316         switch (ehdr.e_machine) {
 317                 case EM_ARM:
 318                         plt_header_size = 20;
 319                         plt_entry_size = 12;
 320                         break;
 321
 322                 case EM_AARCH64:
 323                         plt_header_size = 32;
 324                         plt_entry_size = 16;
 325                         break;
 326
 327                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/sparc/xtensa need to be checked */
 328                         plt_header_size = shdr_plt.sh_entsize;
 329                         plt_entry_size = shdr_plt.sh_entsize;
 330                         break;
 331         }
 332         plt_offset += plt_header_size;
 333
 334         if (shdr_rel_plt.sh_type == SHT_RELA) {
 335                 GElf_Rela pos_mem, *pos;
 336
 337                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 338                                            nr_rel_entries) {
 339                         const char *elf_name = NULL;
 340                         char *demangled = NULL;
 341                         symidx = GELF_R_SYM(pos->r_info);
 342                         gelf_getsym(syms, symidx, &sym);
 343
 344                         elf_name = elf_sym__name(&sym, symstrs);
 345                         demangled = demangle_sym(dso, 0, elf_name);
 346                         if (demangled != NULL)
 347                                 elf_name = demangled;
 348                         snprintf(sympltname, sizeof(sympltname),
 349                                  "%s@plt", elf_name);
 350                         free(demangled);
 351
 352                         f = symbol__new(plt_offset, plt_entry_size,
 353                                         STB_GLOBAL, STT_FUNC, sympltname);
 354                         if (!f)
 355                                 goto out_elf_end;
 356
 357                         plt_offset += plt_entry_size;
 358                         symbols__insert(&dso->symbols, f);
 359                         ++nr;
 360                 }
 361         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 362                 GElf_Rel pos_mem, *pos;
 363                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 364                                           nr_rel_entries) {
 365                         const char *elf_name = NULL;
 366                         char *demangled = NULL;
 367                         symidx = GELF_R_SYM(pos->r_info);
 368                         gelf_getsym(syms, symidx, &sym);
 369
 370                         elf_name = elf_sym__name(&sym, symstrs);
 371                         demangled = demangle_sym(dso, 0, elf_name);
 372                         if (demangled != NULL)
 373                                 elf_name = demangled;
 374                         snprintf(sympltname, sizeof(sympltname),
 375                                  "%s@plt", elf_name);
 376                         free(demangled);
 377
 378                         f = symbol__new(plt_offset, plt_entry_size,
 379                                         STB_GLOBAL, STT_FUNC, sympltname);
 380                         if (!f)
 381                                 goto out_elf_end;
 382
 383                         plt_offset += plt_entry_size;
 384                         symbols__insert(&dso->symbols, f);
 385                         ++nr;
 386                 }
 387         }
 388
 389         err = 0;
 390 out_elf_end:
 391         if (err == 0)
 392                 return nr;
 393         pr_debug("%s: problems reading %s PLT info.\n",
 394                  __func__, dso->long_name);
 395         return 0;
 396 }
 397
 398 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 399 {
 400         return demangle_sym(dso, kmodule, elf_name);
 401 }
 402
 403 /*
 404  * Align offset to 4 bytes as needed for note name and descriptor data.
 405  */
 406 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 407
 408 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 409 {
 410         int err = -1;
 411         GElf_Ehdr ehdr;
 412         GElf_Shdr shdr;
 413         Elf_Data *data;
 414         Elf_Scn *sec;
 415         Elf_Kind ek;
 416         void *ptr;
 417
 418         if (size < BUILD_ID_SIZE)
 419                 goto out;
 420
 421         ek = elf_kind(elf);
 422         if (ek != ELF_K_ELF)
 423                 goto out;
 424
 425         if (gelf_getehdr(elf, &ehdr) == NULL) {
 426                 pr_err("%s: cannot get elf header.\n", __func__);
 427                 goto out;
 428         }
 429
 430         /*
 431          * Check following sections for notes:
 432          *   '.note.gnu.build-id'
 433          *   '.notes'
 434          *   '.note' (VDSO specific)
 435          */
 436         do {
 437                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 438                                           ".note.gnu.build-id", NULL);
 439                 if (sec)
 440                         break;
 441
 442                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 443                                           ".notes", NULL);
 444                 if (sec)
 445                         break;
 446
 447                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 448                                           ".note", NULL);
 449                 if (sec)
 450                         break;
 451
 452                 return err;
 453
 454         } while (0);
 455
 456         data = elf_getdata(sec, NULL);
 457         if (data == NULL)
 458                 goto out;
 459
 460         ptr = data->d_buf;
 461         while (ptr < (data->d_buf + data->d_size)) {
 462                 GElf_Nhdr *nhdr = ptr;
 463                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 464                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 465                 const char *name;
 466
 467                 ptr += sizeof(*nhdr);
 468                 name = ptr;
 469                 ptr += namesz;
 470                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 471                     nhdr->n_namesz == sizeof("GNU")) {
 472                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 473                                 size_t sz = min(size, descsz);
 474                                 memcpy(bf, ptr, sz);
 475                                 memset(bf + sz, 0, size - sz);
 476                                 err = descsz;
 477                                 break;
 478                         }
 479                 }
 480                 ptr += descsz;
 481         }
 482
 483 out:
 484         return err;
 485 }
 486
 487 int filename__read_build_id(const char *filename, void *bf, size_t size)
 488 {
 489         int fd, err = -1;
 490         Elf *elf;
 491
 492         if (size < BUILD_ID_SIZE)
 493                 goto out;
 494
 495         fd = open(filename, O_RDONLY);
 496         if (fd < 0)
 497                 goto out;
 498
 499         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 500         if (elf == NULL) {
 501                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 502                 goto out_close;
 503         }
 504
 505         err = elf_read_build_id(elf, bf, size);
 506
 507         elf_end(elf);
 508 out_close:
 509         close(fd);
 510 out:
 511         return err;
 512 }
 513
 514 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 515 {
 516         int fd, err = -1;
 517
 518         if (size < BUILD_ID_SIZE)
 519                 goto out;
 520
 521         fd = open(filename, O_RDONLY);
 522         if (fd < 0)
 523                 goto out;
 524
 525         while (1) {
 526                 char bf[BUFSIZ];
 527                 GElf_Nhdr nhdr;
 528                 size_t namesz, descsz;
 529
 530                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 531                         break;
 532
 533                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 534                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 535                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 536                     nhdr.n_namesz == sizeof("GNU")) {
 537                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 538                                 break;
 539                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 540                                 size_t sz = min(descsz, size);
 541                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 542                                         memset(build_id + sz, 0, size - sz);
 543                                         err = 0;
 544                                         break;
 545                                 }
 546                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 547                                 break;
 548                 } else {
 549                         int n = namesz + descsz;
 550
 551                         if (n > (int)sizeof(bf)) {
 552                                 n = sizeof(bf);
 553                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 554                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 555                         }
 556                         if (read(fd, bf, n) != n)
 557                                 break;
 558                 }
 559         }
 560         close(fd);
 561 out:
 562         return err;
 563 }
 564
 565 int filename__read_debuglink(const char *filename, char *debuglink,
 566                              size_t size)
 567 {
 568         int fd, err = -1;
 569         Elf *elf;
 570         GElf_Ehdr ehdr;
 571         GElf_Shdr shdr;
 572         Elf_Data *data;
 573         Elf_Scn *sec;
 574         Elf_Kind ek;
 575
 576         fd = open(filename, O_RDONLY);
 577         if (fd < 0)
 578                 goto out;
 579
 580         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 581         if (elf == NULL) {
 582                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 583                 goto out_close;
 584         }
 585
 586         ek = elf_kind(elf);
 587         if (ek != ELF_K_ELF)
 588                 goto out_elf_end;
 589
 590         if (gelf_getehdr(elf, &ehdr) == NULL) {
 591                 pr_err("%s: cannot get elf header.\n", __func__);
 592                 goto out_elf_end;
 593         }
 594
 595         sec = elf_section_by_name(elf, &ehdr, &shdr,
 596                                   ".gnu_debuglink", NULL);
 597         if (sec == NULL)
 598                 goto out_elf_end;
 599
 600         data = elf_getdata(sec, NULL);
 601         if (data == NULL)
 602                 goto out_elf_end;
 603
 604         /* the start of this section is a zero-terminated string */
 605         strncpy(debuglink, data->d_buf, size);
 606
 607         err = 0;
 608
 609 out_elf_end:
 610         elf_end(elf);
 611 out_close:
 612         close(fd);
 613 out:
 614         return err;
 615 }
 616
 617 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 618 {
 619         static unsigned int const endian = 1;
 620
 621         dso->needs_swap = DSO_SWAP__NO;
 622
 623         switch (eidata) {
 624         case ELFDATA2LSB:
 625                 /* We are big endian, DSO is little endian. */
 626                 if (*(unsigned char const *)&endian != 1)
 627                         dso->needs_swap = DSO_SWAP__YES;
 628                 break;
 629
 630         case ELFDATA2MSB:
 631                 /* We are little endian, DSO is big endian. */
 632                 if (*(unsigned char const *)&endian != 0)
 633                         dso->needs_swap = DSO_SWAP__YES;
 634                 break;
 635
 636         default:
 637                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 638                 return -EINVAL;
 639         }
 640
 641         return 0;
 642 }
 643
 644 bool symsrc__possibly_runtime(struct symsrc *ss)
 645 {
 646         return ss->dynsym || ss->opdsec;
 647 }
 648
 649 bool symsrc__has_symtab(struct symsrc *ss)
 650 {
 651         return ss->symtab != NULL;
 652 }
 653
 654 void symsrc__destroy(struct symsrc *ss)
 655 {
 656         zfree(&ss->name);
 657         elf_end(ss->elf);
 658         close(ss->fd);
 659 }
 660
 661 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 662 {
 663         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 664 }
 665
 666 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 667                  enum dso_binary_type type)
 668 {
 669         int err = -1;
 670         GElf_Ehdr ehdr;
 671         Elf *elf;
 672         int fd;
 673
 674         if (dso__needs_decompress(dso)) {
 675                 fd = dso__decompress_kmodule_fd(dso, name);
 676                 if (fd < 0)
 677                         return -1;
 678
 679                 type = dso->symtab_type;
 680         } else {
 681                 fd = open(name, O_RDONLY);
 682                 if (fd < 0) {
 683                         dso->load_errno = errno;
 684                         return -1;
 685                 }
 686         }
 687
 688         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 689         if (elf == NULL) {
 690                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 691                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 692                 goto out_close;
 693         }
 694
 695         if (gelf_getehdr(elf, &ehdr) == NULL) {
 696                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 697                 pr_debug("%s: cannot get elf header.\n", __func__);
 698                 goto out_elf_end;
 699         }
 700
 701         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 702                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 703                 goto out_elf_end;
 704         }
 705
 706         /* Always reject images with a mismatched build-id: */
 707         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 708                 u8 build_id[BUILD_ID_SIZE];
 709
 710                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 711                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 712                         goto out_elf_end;
 713                 }
 714
 715                 if (!dso__build_id_equal(dso, build_id)) {
 716                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 717                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 718                         goto out_elf_end;
 719                 }
 720         }
 721
 722         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 723
 724         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 725                         NULL);
 726         if (ss->symshdr.sh_type != SHT_SYMTAB)
 727                 ss->symtab = NULL;
 728
 729         ss->dynsym_idx = 0;
 730         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 731                         &ss->dynsym_idx);
 732         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 733                 ss->dynsym = NULL;
 734
 735         ss->opdidx = 0;
 736         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 737                         &ss->opdidx);
 738         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 739                 ss->opdsec = NULL;
 740
 741         if (dso->kernel == DSO_TYPE_USER)
 742                 ss->adjust_symbols = true;
 743         else
 744                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 745
 746         ss->name   = strdup(name);
 747         if (!ss->name) {
 748                 dso->load_errno = errno;
 749                 goto out_elf_end;
 750         }
 751
 752         ss->elf    = elf;
 753         ss->fd     = fd;
 754         ss->ehdr   = ehdr;
 755         ss->type   = type;
 756
 757         return 0;
 758
 759 out_elf_end:
 760         elf_end(elf);
 761 out_close:
 762         close(fd);
 763         return err;
 764 }
 765
 766 /**
 767  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 768  * @kmap: kernel maps and relocation reference symbol
 769  *
 770  * This function returns %true if we are dealing with the kernel maps and the
 771  * relocation reference symbol has not yet been found.  Otherwise %false is
 772  * returned.
 773  */
 774 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 775 {
 776         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 777                !kmap->ref_reloc_sym->unrelocated_addr;
 778 }
 779
 780 /**
 781  * ref_reloc - kernel relocation offset.
 782  * @kmap: kernel maps and relocation reference symbol
 783  *
 784  * This function returns the offset of kernel addresses as determined by using
 785  * the relocation reference symbol i.e. if the kernel has not been relocated
 786  * then the return value is zero.
 787  */
 788 static u64 ref_reloc(struct kmap *kmap)
 789 {
 790         if (kmap && kmap->ref_reloc_sym &&
 791             kmap->ref_reloc_sym->unrelocated_addr)
 792                 return kmap->ref_reloc_sym->addr -
 793                        kmap->ref_reloc_sym->unrelocated_addr;
 794         return 0;
 795 }
 796
 797 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 798                 GElf_Sym *sym __maybe_unused) { }
 799
 800 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 801                                       GElf_Sym *sym, GElf_Shdr *shdr,
 802                                       struct map_groups *kmaps, struct kmap *kmap,
 803                                       struct dso **curr_dsop, struct map **curr_mapp,
 804                                       const char *section_name,
 805                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 806 {
 807         struct dso *curr_dso = *curr_dsop;
 808         struct map *curr_map;
 809         char dso_name[PATH_MAX];
 810
 811         /* Adjust symbol to map to file offset */
 812         if (adjust_kernel_syms)
 813                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 814
 815         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 816                 return 0;
 817
 818         if (strcmp(section_name, ".text") == 0) {
 819                 /*
 820                  * The initial kernel mapping is based on
 821                  * kallsyms and identity maps.  Overwrite it to
 822                  * map to the kernel dso.
 823                  */
 824                 if (*remap_kernel && dso->kernel) {
 825                         *remap_kernel = false;
 826                         map->start = shdr->sh_addr + ref_reloc(kmap);
 827                         map->end = map->start + shdr->sh_size;
 828                         map->pgoff = shdr->sh_offset;
 829                         map->map_ip = map__map_ip;
 830                         map->unmap_ip = map__unmap_ip;
 831                         /* Ensure maps are correctly ordered */
 832                         if (kmaps) {
 833                                 map__get(map);
 834                                 map_groups__remove(kmaps, map);
 835                                 map_groups__insert(kmaps, map);
 836                                 map__put(map);
 837                         }
 838                 }
 839
 840                 /*
 841                  * The initial module mapping is based on
 842                  * /proc/modules mapped to offset zero.
 843                  * Overwrite it to map to the module dso.
 844                  */
 845                 if (*remap_kernel && kmodule) {
 846                         *remap_kernel = false;
 847                         map->pgoff = shdr->sh_offset;
 848                 }
 849
 850                 *curr_mapp = map;
 851                 *curr_dsop = dso;
 852                 return 0;
 853         }
 854
 855         if (!kmap)
 856                 return 0;
 857
 858         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 859
 860         curr_map = map_groups__find_by_name(kmaps, dso_name);
 861         if (curr_map == NULL) {
 862                 u64 start = sym->st_value;
 863
 864                 if (kmodule)
 865                         start += map->start + shdr->sh_offset;
 866
 867                 curr_dso = dso__new(dso_name);
 868                 if (curr_dso == NULL)
 869                         return -1;
 870                 curr_dso->kernel = dso->kernel;
 871                 curr_dso->long_name = dso->long_name;
 872                 curr_dso->long_name_len = dso->long_name_len;
 873                 curr_map = map__new2(start, curr_dso);
 874                 dso__put(curr_dso);
 875                 if (curr_map == NULL)
 876                         return -1;
 877
 878                 if (adjust_kernel_syms) {
 879                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 880                         curr_map->end    = curr_map->start + shdr->sh_size;
 881                         curr_map->pgoff  = shdr->sh_offset;
 882                 } else {
 883                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 884                 }
 885                 curr_dso->symtab_type = dso->symtab_type;
 886                 map_groups__insert(kmaps, curr_map);
 887                 /*
 888                  * Add it before we drop the referece to curr_map, i.e. while
 889                  * we still are sure to have a reference to this DSO via
 890                  * *curr_map->dso.
 891                  */
 892                 dsos__add(&map->groups->machine->dsos, curr_dso);
 893                 /* kmaps already got it */
 894                 map__put(curr_map);
 895                 dso__set_loaded(curr_dso);
 896                 *curr_mapp = curr_map;
 897                 *curr_dsop = curr_dso;
 898         } else
 899                 *curr_dsop = curr_map->dso;
 900
 901         return 0;
 902 }
 903
 904 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 905                   struct symsrc *runtime_ss, int kmodule)
 906 {
 907         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 908         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 909         struct map *curr_map = map;
 910         struct dso *curr_dso = dso;
 911         Elf_Data *symstrs, *secstrs;
 912         uint32_t nr_syms;
 913         int err = -1;
 914         uint32_t idx;
 915         GElf_Ehdr ehdr;
 916         GElf_Shdr shdr;
 917         GElf_Shdr tshdr;
 918         Elf_Data *syms, *opddata = NULL;
 919         GElf_Sym sym;
 920         Elf_Scn *sec, *sec_strndx;
 921         Elf *elf;
 922         int nr = 0;
 923         bool remap_kernel = false, adjust_kernel_syms = false;
 924
 925         if (kmap && !kmaps)
 926                 return -1;
 927
 928         dso->symtab_type = syms_ss->type;
 929         dso->is_64_bit = syms_ss->is_64_bit;
 930         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 931
 932         /*
 933          * Modules may already have symbols from kallsyms, but those symbols
 934          * have the wrong values for the dso maps, so remove them.
 935          */
 936         if (kmodule && syms_ss->symtab)
 937                 symbols__delete(&dso->symbols);
 938
 939         if (!syms_ss->symtab) {
 940                 /*
 941                  * If the vmlinux is stripped, fail so we will fall back
 942                  * to using kallsyms. The vmlinux runtime symbols aren't
 943                  * of much use.
 944                  */
 945                 if (dso->kernel)
 946                         goto out_elf_end;
 947
 948                 syms_ss->symtab  = syms_ss->dynsym;
 949                 syms_ss->symshdr = syms_ss->dynshdr;
 950         }
 951
 952         elf = syms_ss->elf;
 953         ehdr = syms_ss->ehdr;
 954         sec = syms_ss->symtab;
 955         shdr = syms_ss->symshdr;
 956
 957         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 958                                 ".text", NULL))
 959                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 960
 961         if (runtime_ss->opdsec)
 962                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 963
 964         syms = elf_getdata(sec, NULL);
 965         if (syms == NULL)
 966                 goto out_elf_end;
 967
 968         sec = elf_getscn(elf, shdr.sh_link);
 969         if (sec == NULL)
 970                 goto out_elf_end;
 971
 972         symstrs = elf_getdata(sec, NULL);
 973         if (symstrs == NULL)
 974                 goto out_elf_end;
 975
 976         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 977         if (sec_strndx == NULL)
 978                 goto out_elf_end;
 979
 980         secstrs = elf_getdata(sec_strndx, NULL);
 981         if (secstrs == NULL)
 982                 goto out_elf_end;
 983
 984         nr_syms = shdr.sh_size / shdr.sh_entsize;
 985
 986         memset(&sym, 0, sizeof(sym));
 987
 988         /*
 989          * The kernel relocation symbol is needed in advance in order to adjust
 990          * kernel maps correctly.
 991          */
 992         if (ref_reloc_sym_not_found(kmap)) {
 993                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 994                         const char *elf_name = elf_sym__name(&sym, symstrs);
 995
 996                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 997                                 continue;
 998                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 999                         map->reloc = kmap->ref_reloc_sym->addr -
1000                                      kmap->ref_reloc_sym->unrelocated_addr;
1001                         break;
1002                 }
1003         }
1004
1005         /*
1006          * Handle any relocation of vdso necessary because older kernels
1007          * attempted to prelink vdso to its virtual address.
1008          */
1009         if (dso__is_vdso(dso))
1010                 map->reloc = map->start - dso->text_offset;
1011
1012         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1013         /*
1014          * Initial kernel and module mappings do not map to the dso.
1015          * Flag the fixups.
1016          */
1017         if (dso->kernel || kmodule) {
1018                 remap_kernel = true;
1019                 adjust_kernel_syms = dso->adjust_symbols;
1020         }
1021         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1022                 struct symbol *f;
1023                 const char *elf_name = elf_sym__name(&sym, symstrs);
1024                 char *demangled = NULL;
1025                 int is_label = elf_sym__is_label(&sym);
1026                 const char *section_name;
1027                 bool used_opd = false;
1028
1029                 if (!is_label && !elf_sym__filter(&sym))
1030                         continue;
1031
1032                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1033                  * don't identify functions, so will confuse the profile
1034                  * output: */
1035                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1036                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1037                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1038                                 continue;
1039                 }
1040
1041                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1042                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1043                         u64 *opd = opddata->d_buf + offset;
1044                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1045                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1046                                         sym.st_value);
1047                         used_opd = true;
1048                 }
1049                 /*
1050                  * When loading symbols in a data mapping, ABS symbols (which
1051                  * has a value of SHN_ABS in its st_shndx) failed at
1052                  * elf_getscn().  And it marks the loading as a failure so
1053                  * already loaded symbols cannot be fixed up.
1054                  *
1055                  * I'm not sure what should be done. Just ignore them for now.
1056                  * - Namhyung Kim
1057                  */
1058                 if (sym.st_shndx == SHN_ABS)
1059                         continue;
1060
1061                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1062                 if (!sec)
1063                         goto out_elf_end;
1064
1065                 gelf_getshdr(sec, &shdr);
1066
1067                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1068                         continue;
1069
1070                 section_name = elf_sec__name(&shdr, secstrs);
1071
1072                 /* On ARM, symbols for thumb functions have 1 added to
1073                  * the symbol address as a flag - remove it */
1074                 if ((ehdr.e_machine == EM_ARM) &&
1075                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1076                     (sym.st_value & 1))
1077                         --sym.st_value;
1078
1079                 if (dso->kernel || kmodule) {
1080                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1081                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1082                                 goto out_elf_end;
1083                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1084                            (!used_opd && syms_ss->adjust_symbols)) {
1085                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1086                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1087                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1088                                   (u64)shdr.sh_offset);
1089                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1090                 }
1091
1092                 demangled = demangle_sym(dso, kmodule, elf_name);
1093                 if (demangled != NULL)
1094                         elf_name = demangled;
1095
1096                 f = symbol__new(sym.st_value, sym.st_size,
1097                                 GELF_ST_BIND(sym.st_info),
1098                                 GELF_ST_TYPE(sym.st_info), elf_name);
1099                 free(demangled);
1100                 if (!f)
1101                         goto out_elf_end;
1102
1103                 arch__sym_update(f, &sym);
1104
1105                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1106                 nr++;
1107         }
1108
1109         /*
1110          * For misannotated, zeroed, ASM function sizes.
1111          */
1112         if (nr > 0) {
1113                 symbols__fixup_end(&dso->symbols);
1114                 symbols__fixup_duplicate(&dso->symbols);
1115                 if (kmap) {
1116                         /*
1117                          * We need to fixup this here too because we create new
1118                          * maps here, for things like vsyscall sections.
1119                          */
1120                         map_groups__fixup_end(kmaps);
1121                 }
1122         }
1123         err = nr;
1124 out_elf_end:
1125         return err;
1126 }
1127
1128 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1129 {
1130         GElf_Phdr phdr;
1131         size_t i, phdrnum;
1132         int err;
1133         u64 sz;
1134
1135         if (elf_getphdrnum(elf, &phdrnum))
1136                 return -1;
1137
1138         for (i = 0; i < phdrnum; i++) {
1139                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1140                         return -1;
1141                 if (phdr.p_type != PT_LOAD)
1142                         continue;
1143                 if (exe) {
1144                         if (!(phdr.p_flags & PF_X))
1145                                 continue;
1146                 } else {
1147                         if (!(phdr.p_flags & PF_R))
1148                                 continue;
1149                 }
1150                 sz = min(phdr.p_memsz, phdr.p_filesz);
1151                 if (!sz)
1152                         continue;
1153                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1154                 if (err)
1155                         return err;
1156         }
1157         return 0;
1158 }
1159
1160 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1161                     bool *is_64_bit)
1162 {
1163         int err;
1164         Elf *elf;
1165
1166         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1167         if (elf == NULL)
1168                 return -1;
1169
1170         if (is_64_bit)
1171                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1172
1173         err = elf_read_maps(elf, exe, mapfn, data);
1174
1175         elf_end(elf);
1176         return err;
1177 }
1178
1179 enum dso_type dso__type_fd(int fd)
1180 {
1181         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1182         GElf_Ehdr ehdr;
1183         Elf_Kind ek;
1184         Elf *elf;
1185
1186         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1187         if (elf == NULL)
1188                 goto out;
1189
1190         ek = elf_kind(elf);
1191         if (ek != ELF_K_ELF)
1192                 goto out_end;
1193
1194         if (gelf_getclass(elf) == ELFCLASS64) {
1195                 dso_type = DSO__TYPE_64BIT;
1196                 goto out_end;
1197         }
1198
1199         if (gelf_getehdr(elf, &ehdr) == NULL)
1200                 goto out_end;
1201
1202         if (ehdr.e_machine == EM_X86_64)
1203                 dso_type = DSO__TYPE_X32BIT;
1204         else
1205                 dso_type = DSO__TYPE_32BIT;
1206 out_end:
1207         elf_end(elf);
1208 out:
1209         return dso_type;
1210 }
1211
1212 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1213 {
1214         ssize_t r;
1215         size_t n;
1216         int err = -1;
1217         char *buf = malloc(page_size);
1218
1219         if (buf == NULL)
1220                 return -1;
1221
1222         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1223                 goto out;
1224
1225         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1226                 goto out;
1227
1228         while (len) {
1229                 n = page_size;
1230                 if (len < n)
1231                         n = len;
1232                 /* Use read because mmap won't work on proc files */
1233                 r = read(from, buf, n);
1234                 if (r < 0)
1235                         goto out;
1236                 if (!r)
1237                         break;
1238                 n = r;
1239                 r = write(to, buf, n);
1240                 if (r < 0)
1241                         goto out;
1242                 if ((size_t)r != n)
1243                         goto out;
1244                 len -= n;
1245         }
1246
1247         err = 0;
1248 out:
1249         free(buf);
1250         return err;
1251 }
1252
1253 struct kcore {
1254         int fd;
1255         int elfclass;
1256         Elf *elf;
1257         GElf_Ehdr ehdr;
1258 };
1259
1260 static int kcore__open(struct kcore *kcore, const char *filename)
1261 {
1262         GElf_Ehdr *ehdr;
1263
1264         kcore->fd = open(filename, O_RDONLY);
1265         if (kcore->fd == -1)
1266                 return -1;
1267
1268         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1269         if (!kcore->elf)
1270                 goto out_close;
1271
1272         kcore->elfclass = gelf_getclass(kcore->elf);
1273         if (kcore->elfclass == ELFCLASSNONE)
1274                 goto out_end;
1275
1276         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1277         if (!ehdr)
1278                 goto out_end;
1279
1280         return 0;
1281
1282 out_end:
1283         elf_end(kcore->elf);
1284 out_close:
1285         close(kcore->fd);
1286         return -1;
1287 }
1288
1289 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1290                        bool temp)
1291 {
1292         kcore->elfclass = elfclass;
1293
1294         if (temp)
1295                 kcore->fd = mkstemp(filename);
1296         else
1297                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1298         if (kcore->fd == -1)
1299                 return -1;
1300
1301         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1302         if (!kcore->elf)
1303                 goto out_close;
1304
1305         if (!gelf_newehdr(kcore->elf, elfclass))
1306                 goto out_end;
1307
1308         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1309
1310         return 0;
1311
1312 out_end:
1313         elf_end(kcore->elf);
1314 out_close:
1315         close(kcore->fd);
1316         unlink(filename);
1317         return -1;
1318 }
1319
1320 static void kcore__close(struct kcore *kcore)
1321 {
1322         elf_end(kcore->elf);
1323         close(kcore->fd);
1324 }
1325
1326 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1327 {
1328         GElf_Ehdr *ehdr = &to->ehdr;
1329         GElf_Ehdr *kehdr = &from->ehdr;
1330
1331         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1332         ehdr->e_type      = kehdr->e_type;
1333         ehdr->e_machine   = kehdr->e_machine;
1334         ehdr->e_version   = kehdr->e_version;
1335         ehdr->e_entry     = 0;
1336         ehdr->e_shoff     = 0;
1337         ehdr->e_flags     = kehdr->e_flags;
1338         ehdr->e_phnum     = count;
1339         ehdr->e_shentsize = 0;
1340         ehdr->e_shnum     = 0;
1341         ehdr->e_shstrndx  = 0;
1342
1343         if (from->elfclass == ELFCLASS32) {
1344                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1345                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1346                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1347         } else {
1348                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1349                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1350                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1351         }
1352
1353         if (!gelf_update_ehdr(to->elf, ehdr))
1354                 return -1;
1355
1356         if (!gelf_newphdr(to->elf, count))
1357                 return -1;
1358
1359         return 0;
1360 }
1361
1362 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1363                            u64 addr, u64 len)
1364 {
1365         GElf_Phdr phdr = {
1366                 .p_type         = PT_LOAD,
1367                 .p_flags        = PF_R | PF_W | PF_X,
1368                 .p_offset       = offset,
1369                 .p_vaddr        = addr,
1370                 .p_paddr        = 0,
1371                 .p_filesz       = len,
1372                 .p_memsz        = len,
1373                 .p_align        = page_size,
1374         };
1375
1376         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1377                 return -1;
1378
1379         return 0;
1380 }
1381
1382 static off_t kcore__write(struct kcore *kcore)
1383 {
1384         return elf_update(kcore->elf, ELF_C_WRITE);
1385 }
1386
1387 struct phdr_data {
1388         off_t offset;
1389         u64 addr;
1390         u64 len;
1391         struct list_head node;
1392 };
1393
1394 struct kcore_copy_info {
1395         u64 stext;
1396         u64 etext;
1397         u64 first_symbol;
1398         u64 last_symbol;
1399         u64 first_module;
1400         u64 last_module_symbol;
1401         size_t phnum;
1402         struct phdr_data kernel_map;
1403         struct phdr_data modules_map;
1404         struct list_head phdrs;
1405 };
1406
1407 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1408                                         u64 start)
1409 {
1410         struct kcore_copy_info *kci = arg;
1411
1412         if (!kallsyms__is_function(type))
1413                 return 0;
1414
1415         if (strchr(name, '[')) {
1416                 if (start > kci->last_module_symbol)
1417                         kci->last_module_symbol = start;
1418                 return 0;
1419         }
1420
1421         if (!kci->first_symbol || start < kci->first_symbol)
1422                 kci->first_symbol = start;
1423
1424         if (!kci->last_symbol || start > kci->last_symbol)
1425                 kci->last_symbol = start;
1426
1427         if (!strcmp(name, "_stext")) {
1428                 kci->stext = start;
1429                 return 0;
1430         }
1431
1432         if (!strcmp(name, "_etext")) {
1433                 kci->etext = start;
1434                 return 0;
1435         }
1436
1437         return 0;
1438 }
1439
1440 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1441                                       const char *dir)
1442 {
1443         char kallsyms_filename[PATH_MAX];
1444
1445         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1446
1447         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1448                 return -1;
1449
1450         if (kallsyms__parse(kallsyms_filename, kci,
1451                             kcore_copy__process_kallsyms) < 0)
1452                 return -1;
1453
1454         return 0;
1455 }
1456
1457 static int kcore_copy__process_modules(void *arg,
1458                                        const char *name __maybe_unused,
1459                                        u64 start, u64 size __maybe_unused)
1460 {
1461         struct kcore_copy_info *kci = arg;
1462
1463         if (!kci->first_module || start < kci->first_module)
1464                 kci->first_module = start;
1465
1466         return 0;
1467 }
1468
1469 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1470                                      const char *dir)
1471 {
1472         char modules_filename[PATH_MAX];
1473
1474         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1475
1476         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1477                 return -1;
1478
1479         if (modules__parse(modules_filename, kci,
1480                            kcore_copy__process_modules) < 0)
1481                 return -1;
1482
1483         return 0;
1484 }
1485
1486 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1487                             u64 s, u64 e)
1488 {
1489         if (p->addr || s < start || s >= end)
1490                 return;
1491
1492         p->addr = s;
1493         p->offset = (s - start) + pgoff;
1494         p->len = e < end ? e - s : end - s;
1495 }
1496
1497 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1498 {
1499         struct kcore_copy_info *kci = data;
1500         u64 end = start + len;
1501
1502         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1503                         kci->etext);
1504
1505         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1506                         kci->last_module_symbol);
1507
1508         return 0;
1509 }
1510
1511 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1512 {
1513         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1514                 return -1;
1515
1516         if (kci->kernel_map.len)
1517                 list_add_tail(&kci->kernel_map.node, &kci->phdrs);
1518         if (kci->modules_map.len)
1519                 list_add_tail(&kci->modules_map.node, &kci->phdrs);
1520
1521         kci->phnum = !!kci->kernel_map.len + !!kci->modules_map.len;
1522
1523         return 0;
1524 }
1525
1526 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1527                                  Elf *elf)
1528 {
1529         if (kcore_copy__parse_kallsyms(kci, dir))
1530                 return -1;
1531
1532         if (kcore_copy__parse_modules(kci, dir))
1533                 return -1;
1534
1535         if (kci->stext)
1536                 kci->stext = round_down(kci->stext, page_size);
1537         else
1538                 kci->stext = round_down(kci->first_symbol, page_size);
1539
1540         if (kci->etext) {
1541                 kci->etext = round_up(kci->etext, page_size);
1542         } else if (kci->last_symbol) {
1543                 kci->etext = round_up(kci->last_symbol, page_size);
1544                 kci->etext += page_size;
1545         }
1546
1547         kci->first_module = round_down(kci->first_module, page_size);
1548
1549         if (kci->last_module_symbol) {
1550                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1551                                                    page_size);
1552                 kci->last_module_symbol += page_size;
1553         }
1554
1555         if (!kci->stext || !kci->etext)
1556                 return -1;
1557
1558         if (kci->first_module && !kci->last_module_symbol)
1559                 return -1;
1560
1561         return kcore_copy__read_maps(kci, elf);
1562 }
1563
1564 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1565                                  const char *name)
1566 {
1567         char from_filename[PATH_MAX];
1568         char to_filename[PATH_MAX];
1569
1570         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1571         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1572
1573         return copyfile_mode(from_filename, to_filename, 0400);
1574 }
1575
1576 static int kcore_copy__unlink(const char *dir, const char *name)
1577 {
1578         char filename[PATH_MAX];
1579
1580         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1581
1582         return unlink(filename);
1583 }
1584
1585 static int kcore_copy__compare_fds(int from, int to)
1586 {
1587         char *buf_from;
1588         char *buf_to;
1589         ssize_t ret;
1590         size_t len;
1591         int err = -1;
1592
1593         buf_from = malloc(page_size);
1594         buf_to = malloc(page_size);
1595         if (!buf_from || !buf_to)
1596                 goto out;
1597
1598         while (1) {
1599                 /* Use read because mmap won't work on proc files */
1600                 ret = read(from, buf_from, page_size);
1601                 if (ret < 0)
1602                         goto out;
1603
1604                 if (!ret)
1605                         break;
1606
1607                 len = ret;
1608
1609                 if (readn(to, buf_to, len) != (int)len)
1610                         goto out;
1611
1612                 if (memcmp(buf_from, buf_to, len))
1613                         goto out;
1614         }
1615
1616         err = 0;
1617 out:
1618         free(buf_to);
1619         free(buf_from);
1620         return err;
1621 }
1622
1623 static int kcore_copy__compare_files(const char *from_filename,
1624                                      const char *to_filename)
1625 {
1626         int from, to, err = -1;
1627
1628         from = open(from_filename, O_RDONLY);
1629         if (from < 0)
1630                 return -1;
1631
1632         to = open(to_filename, O_RDONLY);
1633         if (to < 0)
1634                 goto out_close_from;
1635
1636         err = kcore_copy__compare_fds(from, to);
1637
1638         close(to);
1639 out_close_from:
1640         close(from);
1641         return err;
1642 }
1643
1644 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1645                                     const char *name)
1646 {
1647         char from_filename[PATH_MAX];
1648         char to_filename[PATH_MAX];
1649
1650         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1651         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1652
1653         return kcore_copy__compare_files(from_filename, to_filename);
1654 }
1655
1656 /**
1657  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1658  * @from_dir: from directory
1659  * @to_dir: to directory
1660  *
1661  * This function copies kallsyms, modules and kcore files from one directory to
1662  * another.  kallsyms and modules are copied entirely.  Only code segments are
1663  * copied from kcore.  It is assumed that two segments suffice: one for the
1664  * kernel proper and one for all the modules.  The code segments are determined
1665  * from kallsyms and modules files.  The kernel map starts at _stext or the
1666  * lowest function symbol, and ends at _etext or the highest function symbol.
1667  * The module map starts at the lowest module address and ends at the highest
1668  * module symbol.  Start addresses are rounded down to the nearest page.  End
1669  * addresses are rounded up to the nearest page.  An extra page is added to the
1670  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1671  * symbol too.  Because it contains only code sections, the resulting kcore is
1672  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1673  * is not the same for the kernel map and the modules map.  That happens because
1674  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1675  * kallsyms and modules files are compared with their copies to check that
1676  * modules have not been loaded or unloaded while the copies were taking place.
1677  *
1678  * Return: %0 on success, %-1 on failure.
1679  */
1680 int kcore_copy(const char *from_dir, const char *to_dir)
1681 {
1682         struct kcore kcore;
1683         struct kcore extract;
1684         int idx = 0, err = -1;
1685         off_t offset = page_size, sz, modules_offset = 0;
1686         struct kcore_copy_info kci = { .stext = 0, };
1687         char kcore_filename[PATH_MAX];
1688         char extract_filename[PATH_MAX];
1689
1690         INIT_LIST_HEAD(&kci.phdrs);
1691
1692         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1693                 return -1;
1694
1695         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1696                 goto out_unlink_kallsyms;
1697
1698         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1699         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1700
1701         if (kcore__open(&kcore, kcore_filename))
1702                 goto out_unlink_modules;
1703
1704         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1705                 goto out_kcore_close;
1706
1707         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1708                 goto out_kcore_close;
1709
1710         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1711                 goto out_extract_close;
1712
1713         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1714                             kci.kernel_map.len))
1715                 goto out_extract_close;
1716
1717         if (kci.modules_map.addr) {
1718                 modules_offset = offset + kci.kernel_map.len;
1719                 if (kcore__add_phdr(&extract, idx, modules_offset,
1720                                     kci.modules_map.addr, kci.modules_map.len))
1721                         goto out_extract_close;
1722         }
1723
1724         sz = kcore__write(&extract);
1725         if (sz < 0 || sz > offset)
1726                 goto out_extract_close;
1727
1728         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1729                        kci.kernel_map.len))
1730                 goto out_extract_close;
1731
1732         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1733                                          extract.fd, modules_offset,
1734                                          kci.modules_map.len))
1735                 goto out_extract_close;
1736
1737         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1738                 goto out_extract_close;
1739
1740         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1741                 goto out_extract_close;
1742
1743         err = 0;
1744
1745 out_extract_close:
1746         kcore__close(&extract);
1747         if (err)
1748                 unlink(extract_filename);
1749 out_kcore_close:
1750         kcore__close(&kcore);
1751 out_unlink_modules:
1752         if (err)
1753                 kcore_copy__unlink(to_dir, "modules");
1754 out_unlink_kallsyms:
1755         if (err)
1756                 kcore_copy__unlink(to_dir, "kallsyms");
1757
1758         return err;
1759 }
1760
1761 int kcore_extract__create(struct kcore_extract *kce)
1762 {
1763         struct kcore kcore;
1764         struct kcore extract;
1765         size_t count = 1;
1766         int idx = 0, err = -1;
1767         off_t offset = page_size, sz;
1768
1769         if (kcore__open(&kcore, kce->kcore_filename))
1770                 return -1;
1771
1772         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1773         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1774                 goto out_kcore_close;
1775
1776         if (kcore__copy_hdr(&kcore, &extract, count))
1777                 goto out_extract_close;
1778
1779         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1780                 goto out_extract_close;
1781
1782         sz = kcore__write(&extract);
1783         if (sz < 0 || sz > offset)
1784                 goto out_extract_close;
1785
1786         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1787                 goto out_extract_close;
1788
1789         err = 0;
1790
1791 out_extract_close:
1792         kcore__close(&extract);
1793         if (err)
1794                 unlink(kce->extract_filename);
1795 out_kcore_close:
1796         kcore__close(&kcore);
1797
1798         return err;
1799 }
1800
1801 void kcore_extract__delete(struct kcore_extract *kce)
1802 {
1803         unlink(kce->extract_filename);
1804 }
1805
1806 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1807 /**
1808  * populate_sdt_note : Parse raw data and identify SDT note
1809  * @elf: elf of the opened file
1810  * @data: raw data of a section with description offset applied
1811  * @len: note description size
1812  * @type: type of the note
1813  * @sdt_notes: List to add the SDT note
1814  *
1815  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1816  * if its an SDT note, it appends to @sdt_notes list.
1817  */
1818 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1819                              struct list_head *sdt_notes)
1820 {
1821         const char *provider, *name, *args;
1822         struct sdt_note *tmp = NULL;
1823         GElf_Ehdr ehdr;
1824         GElf_Addr base_off = 0;
1825         GElf_Shdr shdr;
1826         int ret = -EINVAL;
1827
1828         union {
1829                 Elf64_Addr a64[NR_ADDR];
1830                 Elf32_Addr a32[NR_ADDR];
1831         } buf;
1832
1833         Elf_Data dst = {
1834                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1835                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1836                 .d_off = 0, .d_align = 0
1837         };
1838         Elf_Data src = {
1839                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1840                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1841                 .d_align = 0
1842         };
1843
1844         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1845         if (!tmp) {
1846                 ret = -ENOMEM;
1847                 goto out_err;
1848         }
1849
1850         INIT_LIST_HEAD(&tmp->note_list);
1851
1852         if (len < dst.d_size + 3)
1853                 goto out_free_note;
1854
1855         /* Translation from file representation to memory representation */
1856         if (gelf_xlatetom(*elf, &dst, &src,
1857                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1858                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1859                 goto out_free_note;
1860         }
1861
1862         /* Populate the fields of sdt_note */
1863         provider = data + dst.d_size;
1864
1865         name = (const char *)memchr(provider, '\0', data + len - provider);
1866         if (name++ == NULL)
1867                 goto out_free_note;
1868
1869         tmp->provider = strdup(provider);
1870         if (!tmp->provider) {
1871                 ret = -ENOMEM;
1872                 goto out_free_note;
1873         }
1874         tmp->name = strdup(name);
1875         if (!tmp->name) {
1876                 ret = -ENOMEM;
1877                 goto out_free_prov;
1878         }
1879
1880         args = memchr(name, '\0', data + len - name);
1881
1882         /*
1883          * There is no argument if:
1884          * - We reached the end of the note;
1885          * - There is not enough room to hold a potential string;
1886          * - The argument string is empty or just contains ':'.
1887          */
1888         if (args == NULL || data + len - args < 2 ||
1889                 args[1] == ':' || args[1] == '\0')
1890                 tmp->args = NULL;
1891         else {
1892                 tmp->args = strdup(++args);
1893                 if (!tmp->args) {
1894                         ret = -ENOMEM;
1895                         goto out_free_name;
1896                 }
1897         }
1898
1899         if (gelf_getclass(*elf) == ELFCLASS32) {
1900                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1901                 tmp->bit32 = true;
1902         } else {
1903                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1904                 tmp->bit32 = false;
1905         }
1906
1907         if (!gelf_getehdr(*elf, &ehdr)) {
1908                 pr_debug("%s : cannot get elf header.\n", __func__);
1909                 ret = -EBADF;
1910                 goto out_free_args;
1911         }
1912
1913         /* Adjust the prelink effect :
1914          * Find out the .stapsdt.base section.
1915          * This scn will help us to handle prelinking (if present).
1916          * Compare the retrieved file offset of the base section with the
1917          * base address in the description of the SDT note. If its different,
1918          * then accordingly, adjust the note location.
1919          */
1920         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1921                 base_off = shdr.sh_offset;
1922                 if (base_off) {
1923                         if (tmp->bit32)
1924                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1925                                         tmp->addr.a32[1];
1926                         else
1927                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1928                                         tmp->addr.a64[1];
1929                 }
1930         }
1931
1932         list_add_tail(&tmp->note_list, sdt_notes);
1933         return 0;
1934
1935 out_free_args:
1936         free(tmp->args);
1937 out_free_name:
1938         free(tmp->name);
1939 out_free_prov:
1940         free(tmp->provider);
1941 out_free_note:
1942         free(tmp);
1943 out_err:
1944         return ret;
1945 }
1946
1947 /**
1948  * construct_sdt_notes_list : constructs a list of SDT notes
1949  * @elf : elf to look into
1950  * @sdt_notes : empty list_head
1951  *
1952  * Scans the sections in 'elf' for the section
1953  * .note.stapsdt. It, then calls populate_sdt_note to find
1954  * out the SDT events and populates the 'sdt_notes'.
1955  */
1956 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1957 {
1958         GElf_Ehdr ehdr;
1959         Elf_Scn *scn = NULL;
1960         Elf_Data *data;
1961         GElf_Shdr shdr;
1962         size_t shstrndx, next;
1963         GElf_Nhdr nhdr;
1964         size_t name_off, desc_off, offset;
1965         int ret = 0;
1966
1967         if (gelf_getehdr(elf, &ehdr) == NULL) {
1968                 ret = -EBADF;
1969                 goto out_ret;
1970         }
1971         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1972                 ret = -EBADF;
1973                 goto out_ret;
1974         }
1975
1976         /* Look for the required section */
1977         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1978         if (!scn) {
1979                 ret = -ENOENT;
1980                 goto out_ret;
1981         }
1982
1983         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1984                 ret = -ENOENT;
1985                 goto out_ret;
1986         }
1987
1988         data = elf_getdata(scn, NULL);
1989
1990         /* Get the SDT notes */
1991         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1992                                               &desc_off)) > 0; offset = next) {
1993                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1994                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1995                             sizeof(SDT_NOTE_NAME))) {
1996                         /* Check the type of the note */
1997                         if (nhdr.n_type != SDT_NOTE_TYPE)
1998                                 goto out_ret;
1999
2000                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2001                                                 nhdr.n_descsz, sdt_notes);
2002                         if (ret < 0)
2003                                 goto out_ret;
2004                 }
2005         }
2006         if (list_empty(sdt_notes))
2007                 ret = -ENOENT;
2008
2009 out_ret:
2010         return ret;
2011 }
2012
2013 /**
2014  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2015  * @head : empty list_head
2016  * @target : file to find SDT notes from
2017  *
2018  * This opens the file, initializes
2019  * the ELF and then calls construct_sdt_notes_list.
2020  */
2021 int get_sdt_note_list(struct list_head *head, const char *target)
2022 {
2023         Elf *elf;
2024         int fd, ret;
2025
2026         fd = open(target, O_RDONLY);
2027         if (fd < 0)
2028                 return -EBADF;
2029
2030         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2031         if (!elf) {
2032                 ret = -EBADF;
2033                 goto out_close;
2034         }
2035         ret = construct_sdt_notes_list(elf, head);
2036         elf_end(elf);
2037 out_close:
2038         close(fd);
2039         return ret;
2040 }
2041
2042 /**
2043  * cleanup_sdt_note_list : free the sdt notes' list
2044  * @sdt_notes: sdt notes' list
2045  *
2046  * Free up the SDT notes in @sdt_notes.
2047  * Returns the number of SDT notes free'd.
2048  */
2049 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2050 {
2051         struct sdt_note *tmp, *pos;
2052         int nr_free = 0;
2053
2054         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2055                 list_del(&pos->note_list);
2056                 free(pos->name);
2057                 free(pos->provider);
2058                 free(pos);
2059                 nr_free++;
2060         }
2061         return nr_free;
2062 }
2063
2064 /**
2065  * sdt_notes__get_count: Counts the number of sdt events
2066  * @start: list_head to sdt_notes list
2067  *
2068  * Returns the number of SDT notes in a list
2069  */
2070 int sdt_notes__get_count(struct list_head *start)
2071 {
2072         struct sdt_note *sdt_ptr;
2073         int count = 0;
2074
2075         list_for_each_entry(sdt_ptr, start, note_list)
2076                 count++;
2077         return count;
2078 }
2079 #endif
2080
2081 void symbol__elf_init(void)
2082 {
2083         elf_version(EV_CURRENT);
2084 }