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 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
  91 {
  92         return GELF_ST_VISIBILITY(sym->st_other);
  93 }
  94
  95 #ifndef STT_GNU_IFUNC
  96 #define STT_GNU_IFUNC 10
  97 #endif
  98
  99 static inline int elf_sym__is_function(const GElf_Sym *sym)
 100 {
 101         return (elf_sym__type(sym) == STT_FUNC ||
 102                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 103                sym->st_name != 0 &&
 104                sym->st_shndx != SHN_UNDEF;
 105 }
 106
 107 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 108 {
 109         return elf_sym__type(sym) == STT_OBJECT &&
 110                 sym->st_name != 0 &&
 111                 sym->st_shndx != SHN_UNDEF;
 112 }
 113
 114 static inline int elf_sym__is_label(const GElf_Sym *sym)
 115 {
 116         return elf_sym__type(sym) == STT_NOTYPE &&
 117                 sym->st_name != 0 &&
 118                 sym->st_shndx != SHN_UNDEF &&
 119                 sym->st_shndx != SHN_ABS &&
 120                 elf_sym__visibility(sym) != STV_HIDDEN &&
 121                 elf_sym__visibility(sym) != STV_INTERNAL;
 122 }
 123
 124 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
 125 {
 126         switch (type) {
 127         case MAP__FUNCTION:
 128                 return elf_sym__is_function(sym);
 129         case MAP__VARIABLE:
 130                 return elf_sym__is_object(sym);
 131         default:
 132                 return false;
 133         }
 134 }
 135
 136 static inline const char *elf_sym__name(const GElf_Sym *sym,
 137                                         const Elf_Data *symstrs)
 138 {
 139         return symstrs->d_buf + sym->st_name;
 140 }
 141
 142 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 143                                         const Elf_Data *secstrs)
 144 {
 145         return secstrs->d_buf + shdr->sh_name;
 146 }
 147
 148 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 149                                         const Elf_Data *secstrs)
 150 {
 151         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 152 }
 153
 154 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 155                                     const Elf_Data *secstrs)
 156 {
 157         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 158 }
 159
 160 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
 161                           enum map_type type)
 162 {
 163         switch (type) {
 164         case MAP__FUNCTION:
 165                 return elf_sec__is_text(shdr, secstrs);
 166         case MAP__VARIABLE:
 167                 return elf_sec__is_data(shdr, secstrs);
 168         default:
 169                 return false;
 170         }
 171 }
 172
 173 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 174 {
 175         Elf_Scn *sec = NULL;
 176         GElf_Shdr shdr;
 177         size_t cnt = 1;
 178
 179         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 180                 gelf_getshdr(sec, &shdr);
 181
 182                 if ((addr >= shdr.sh_addr) &&
 183                     (addr < (shdr.sh_addr + shdr.sh_size)))
 184                         return cnt;
 185
 186                 ++cnt;
 187         }
 188
 189         return -1;
 190 }
 191
 192 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 193                              GElf_Shdr *shp, const char *name, size_t *idx)
 194 {
 195         Elf_Scn *sec = NULL;
 196         size_t cnt = 1;
 197
 198         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 199         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 200                 return NULL;
 201
 202         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 203                 char *str;
 204
 205                 gelf_getshdr(sec, shp);
 206                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 207                 if (str && !strcmp(name, str)) {
 208                         if (idx)
 209                                 *idx = cnt;
 210                         return sec;
 211                 }
 212                 ++cnt;
 213         }
 214
 215         return NULL;
 216 }
 217
 218 static bool want_demangle(bool is_kernel_sym)
 219 {
 220         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 221 }
 222
 223 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 224 {
 225         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 226         char *demangled = NULL;
 227
 228         /*
 229          * We need to figure out if the object was created from C++ sources
 230          * DWARF DW_compile_unit has this, but we don't always have access
 231          * to it...
 232          */
 233         if (!want_demangle(dso->kernel || kmodule))
 234             return demangled;
 235
 236         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 237         if (demangled == NULL)
 238                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 239         else if (rust_is_mangled(demangled))
 240                 /*
 241                     * Input to Rust demangling is the BFD-demangled
 242                     * name which it Rust-demangles in place.
 243                     */
 244                 rust_demangle_sym(demangled);
 245
 246         return demangled;
 247 }
 248
 249 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 250         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 251              idx < nr_entries; \
 252              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 253
 254 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 255         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 256              idx < nr_entries; \
 257              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 258
 259 /*
 260  * We need to check if we have a .dynsym, so that we can handle the
 261  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 262  * .dynsym or .symtab).
 263  * And always look at the original dso, not at debuginfo packages, that
 264  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 265  */
 266 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
 267 {
 268         uint32_t nr_rel_entries, idx;
 269         GElf_Sym sym;
 270         u64 plt_offset, plt_header_size, plt_entry_size;
 271         GElf_Shdr shdr_plt;
 272         struct symbol *f;
 273         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 274         Elf_Data *reldata, *syms, *symstrs;
 275         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 276         size_t dynsym_idx;
 277         GElf_Ehdr ehdr;
 278         char sympltname[1024];
 279         Elf *elf;
 280         int nr = 0, symidx, err = 0;
 281
 282         if (!ss->dynsym)
 283                 return 0;
 284
 285         elf = ss->elf;
 286         ehdr = ss->ehdr;
 287
 288         scn_dynsym = ss->dynsym;
 289         shdr_dynsym = ss->dynshdr;
 290         dynsym_idx = ss->dynsym_idx;
 291
 292         if (scn_dynsym == NULL)
 293                 goto out_elf_end;
 294
 295         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 296                                           ".rela.plt", NULL);
 297         if (scn_plt_rel == NULL) {
 298                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 299                                                   ".rel.plt", NULL);
 300                 if (scn_plt_rel == NULL)
 301                         goto out_elf_end;
 302         }
 303
 304         err = -1;
 305
 306         if (shdr_rel_plt.sh_link != dynsym_idx)
 307                 goto out_elf_end;
 308
 309         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 310                 goto out_elf_end;
 311
 312         /*
 313          * Fetch the relocation section to find the idxes to the GOT
 314          * and the symbols in the .dynsym they refer to.
 315          */
 316         reldata = elf_getdata(scn_plt_rel, NULL);
 317         if (reldata == NULL)
 318                 goto out_elf_end;
 319
 320         syms = elf_getdata(scn_dynsym, NULL);
 321         if (syms == NULL)
 322                 goto out_elf_end;
 323
 324         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 325         if (scn_symstrs == NULL)
 326                 goto out_elf_end;
 327
 328         symstrs = elf_getdata(scn_symstrs, NULL);
 329         if (symstrs == NULL)
 330                 goto out_elf_end;
 331
 332         if (symstrs->d_size == 0)
 333                 goto out_elf_end;
 334
 335         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 336         plt_offset = shdr_plt.sh_offset;
 337         switch (ehdr.e_machine) {
 338                 case EM_ARM:
 339                         plt_header_size = 20;
 340                         plt_entry_size = 12;
 341                         break;
 342
 343                 case EM_AARCH64:
 344                         plt_header_size = 32;
 345                         plt_entry_size = 16;
 346                         break;
 347
 348                 case EM_SPARC:
 349                         plt_header_size = 48;
 350                         plt_entry_size = 12;
 351                         break;
 352
 353                 case EM_SPARCV9:
 354                         plt_header_size = 128;
 355                         plt_entry_size = 32;
 356                         break;
 357
 358                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 359                         plt_header_size = shdr_plt.sh_entsize;
 360                         plt_entry_size = shdr_plt.sh_entsize;
 361                         break;
 362         }
 363         plt_offset += plt_header_size;
 364
 365         if (shdr_rel_plt.sh_type == SHT_RELA) {
 366                 GElf_Rela pos_mem, *pos;
 367
 368                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 369                                            nr_rel_entries) {
 370                         const char *elf_name = NULL;
 371                         char *demangled = NULL;
 372                         symidx = GELF_R_SYM(pos->r_info);
 373                         gelf_getsym(syms, symidx, &sym);
 374
 375                         elf_name = elf_sym__name(&sym, symstrs);
 376                         demangled = demangle_sym(dso, 0, elf_name);
 377                         if (demangled != NULL)
 378                                 elf_name = demangled;
 379                         snprintf(sympltname, sizeof(sympltname),
 380                                  "%s@plt", elf_name);
 381                         free(demangled);
 382
 383                         f = symbol__new(plt_offset, plt_entry_size,
 384                                         STB_GLOBAL, sympltname);
 385                         if (!f)
 386                                 goto out_elf_end;
 387
 388                         plt_offset += plt_entry_size;
 389                         symbols__insert(&dso->symbols[map->type], f);
 390                         ++nr;
 391                 }
 392         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 393                 GElf_Rel pos_mem, *pos;
 394                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 395                                           nr_rel_entries) {
 396                         const char *elf_name = NULL;
 397                         char *demangled = NULL;
 398                         symidx = GELF_R_SYM(pos->r_info);
 399                         gelf_getsym(syms, symidx, &sym);
 400
 401                         elf_name = elf_sym__name(&sym, symstrs);
 402                         demangled = demangle_sym(dso, 0, elf_name);
 403                         if (demangled != NULL)
 404                                 elf_name = demangled;
 405                         snprintf(sympltname, sizeof(sympltname),
 406                                  "%s@plt", elf_name);
 407                         free(demangled);
 408
 409                         f = symbol__new(plt_offset, plt_entry_size,
 410                                         STB_GLOBAL, sympltname);
 411                         if (!f)
 412                                 goto out_elf_end;
 413
 414                         plt_offset += plt_entry_size;
 415                         symbols__insert(&dso->symbols[map->type], f);
 416                         ++nr;
 417                 }
 418         }
 419
 420         err = 0;
 421 out_elf_end:
 422         if (err == 0)
 423                 return nr;
 424         pr_debug("%s: problems reading %s PLT info.\n",
 425                  __func__, dso->long_name);
 426         return 0;
 427 }
 428
 429 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 430 {
 431         return demangle_sym(dso, kmodule, elf_name);
 432 }
 433
 434 /*
 435  * Align offset to 4 bytes as needed for note name and descriptor data.
 436  */
 437 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 438
 439 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 440 {
 441         int err = -1;
 442         GElf_Ehdr ehdr;
 443         GElf_Shdr shdr;
 444         Elf_Data *data;
 445         Elf_Scn *sec;
 446         Elf_Kind ek;
 447         void *ptr;
 448
 449         if (size < BUILD_ID_SIZE)
 450                 goto out;
 451
 452         ek = elf_kind(elf);
 453         if (ek != ELF_K_ELF)
 454                 goto out;
 455
 456         if (gelf_getehdr(elf, &ehdr) == NULL) {
 457                 pr_err("%s: cannot get elf header.\n", __func__);
 458                 goto out;
 459         }
 460
 461         /*
 462          * Check following sections for notes:
 463          *   '.note.gnu.build-id'
 464          *   '.notes'
 465          *   '.note' (VDSO specific)
 466          */
 467         do {
 468                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 469                                           ".note.gnu.build-id", NULL);
 470                 if (sec)
 471                         break;
 472
 473                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 474                                           ".notes", NULL);
 475                 if (sec)
 476                         break;
 477
 478                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 479                                           ".note", NULL);
 480                 if (sec)
 481                         break;
 482
 483                 return err;
 484
 485         } while (0);
 486
 487         data = elf_getdata(sec, NULL);
 488         if (data == NULL)
 489                 goto out;
 490
 491         ptr = data->d_buf;
 492         while (ptr < (data->d_buf + data->d_size)) {
 493                 GElf_Nhdr *nhdr = ptr;
 494                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 495                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 496                 const char *name;
 497
 498                 ptr += sizeof(*nhdr);
 499                 name = ptr;
 500                 ptr += namesz;
 501                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 502                     nhdr->n_namesz == sizeof("GNU")) {
 503                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 504                                 size_t sz = min(size, descsz);
 505                                 memcpy(bf, ptr, sz);
 506                                 memset(bf + sz, 0, size - sz);
 507                                 err = descsz;
 508                                 break;
 509                         }
 510                 }
 511                 ptr += descsz;
 512         }
 513
 514 out:
 515         return err;
 516 }
 517
 518 int filename__read_build_id(const char *filename, void *bf, size_t size)
 519 {
 520         int fd, err = -1;
 521         Elf *elf;
 522
 523         if (size < BUILD_ID_SIZE)
 524                 goto out;
 525
 526         fd = open(filename, O_RDONLY);
 527         if (fd < 0)
 528                 goto out;
 529
 530         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 531         if (elf == NULL) {
 532                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 533                 goto out_close;
 534         }
 535
 536         err = elf_read_build_id(elf, bf, size);
 537
 538         elf_end(elf);
 539 out_close:
 540         close(fd);
 541 out:
 542         return err;
 543 }
 544
 545 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 546 {
 547         int fd, err = -1;
 548
 549         if (size < BUILD_ID_SIZE)
 550                 goto out;
 551
 552         fd = open(filename, O_RDONLY);
 553         if (fd < 0)
 554                 goto out;
 555
 556         while (1) {
 557                 char bf[BUFSIZ];
 558                 GElf_Nhdr nhdr;
 559                 size_t namesz, descsz;
 560
 561                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 562                         break;
 563
 564                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 565                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 566                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 567                     nhdr.n_namesz == sizeof("GNU")) {
 568                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 569                                 break;
 570                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 571                                 size_t sz = min(descsz, size);
 572                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 573                                         memset(build_id + sz, 0, size - sz);
 574                                         err = 0;
 575                                         break;
 576                                 }
 577                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 578                                 break;
 579                 } else {
 580                         int n = namesz + descsz;
 581
 582                         if (n > (int)sizeof(bf)) {
 583                                 n = sizeof(bf);
 584                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 585                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 586                         }
 587                         if (read(fd, bf, n) != n)
 588                                 break;
 589                 }
 590         }
 591         close(fd);
 592 out:
 593         return err;
 594 }
 595
 596 int filename__read_debuglink(const char *filename, char *debuglink,
 597                              size_t size)
 598 {
 599         int fd, err = -1;
 600         Elf *elf;
 601         GElf_Ehdr ehdr;
 602         GElf_Shdr shdr;
 603         Elf_Data *data;
 604         Elf_Scn *sec;
 605         Elf_Kind ek;
 606
 607         fd = open(filename, O_RDONLY);
 608         if (fd < 0)
 609                 goto out;
 610
 611         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 612         if (elf == NULL) {
 613                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 614                 goto out_close;
 615         }
 616
 617         ek = elf_kind(elf);
 618         if (ek != ELF_K_ELF)
 619                 goto out_elf_end;
 620
 621         if (gelf_getehdr(elf, &ehdr) == NULL) {
 622                 pr_err("%s: cannot get elf header.\n", __func__);
 623                 goto out_elf_end;
 624         }
 625
 626         sec = elf_section_by_name(elf, &ehdr, &shdr,
 627                                   ".gnu_debuglink", NULL);
 628         if (sec == NULL)
 629                 goto out_elf_end;
 630
 631         data = elf_getdata(sec, NULL);
 632         if (data == NULL)
 633                 goto out_elf_end;
 634
 635         /* the start of this section is a zero-terminated string */
 636         strncpy(debuglink, data->d_buf, size);
 637
 638         err = 0;
 639
 640 out_elf_end:
 641         elf_end(elf);
 642 out_close:
 643         close(fd);
 644 out:
 645         return err;
 646 }
 647
 648 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 649 {
 650         static unsigned int const endian = 1;
 651
 652         dso->needs_swap = DSO_SWAP__NO;
 653
 654         switch (eidata) {
 655         case ELFDATA2LSB:
 656                 /* We are big endian, DSO is little endian. */
 657                 if (*(unsigned char const *)&endian != 1)
 658                         dso->needs_swap = DSO_SWAP__YES;
 659                 break;
 660
 661         case ELFDATA2MSB:
 662                 /* We are little endian, DSO is big endian. */
 663                 if (*(unsigned char const *)&endian != 0)
 664                         dso->needs_swap = DSO_SWAP__YES;
 665                 break;
 666
 667         default:
 668                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 669                 return -EINVAL;
 670         }
 671
 672         return 0;
 673 }
 674
 675 bool symsrc__possibly_runtime(struct symsrc *ss)
 676 {
 677         return ss->dynsym || ss->opdsec;
 678 }
 679
 680 bool symsrc__has_symtab(struct symsrc *ss)
 681 {
 682         return ss->symtab != NULL;
 683 }
 684
 685 void symsrc__destroy(struct symsrc *ss)
 686 {
 687         zfree(&ss->name);
 688         elf_end(ss->elf);
 689         close(ss->fd);
 690 }
 691
 692 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 693 {
 694         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 695 }
 696
 697 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 698                  enum dso_binary_type type)
 699 {
 700         int err = -1;
 701         GElf_Ehdr ehdr;
 702         Elf *elf;
 703         int fd;
 704
 705         if (dso__needs_decompress(dso)) {
 706                 fd = dso__decompress_kmodule_fd(dso, name);
 707                 if (fd < 0)
 708                         return -1;
 709
 710                 type = dso->symtab_type;
 711         } else {
 712                 fd = open(name, O_RDONLY);
 713                 if (fd < 0) {
 714                         dso->load_errno = errno;
 715                         return -1;
 716                 }
 717         }
 718
 719         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 720         if (elf == NULL) {
 721                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 722                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 723                 goto out_close;
 724         }
 725
 726         if (gelf_getehdr(elf, &ehdr) == NULL) {
 727                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 728                 pr_debug("%s: cannot get elf header.\n", __func__);
 729                 goto out_elf_end;
 730         }
 731
 732         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 733                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 734                 goto out_elf_end;
 735         }
 736
 737         /* Always reject images with a mismatched build-id: */
 738         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 739                 u8 build_id[BUILD_ID_SIZE];
 740
 741                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 742                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 743                         goto out_elf_end;
 744                 }
 745
 746                 if (!dso__build_id_equal(dso, build_id)) {
 747                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 748                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 749                         goto out_elf_end;
 750                 }
 751         }
 752
 753         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 754
 755         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 756                         NULL);
 757         if (ss->symshdr.sh_type != SHT_SYMTAB)
 758                 ss->symtab = NULL;
 759
 760         ss->dynsym_idx = 0;
 761         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 762                         &ss->dynsym_idx);
 763         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 764                 ss->dynsym = NULL;
 765
 766         ss->opdidx = 0;
 767         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 768                         &ss->opdidx);
 769         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 770                 ss->opdsec = NULL;
 771
 772         if (dso->kernel == DSO_TYPE_USER)
 773                 ss->adjust_symbols = true;
 774         else
 775                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 776
 777         ss->name   = strdup(name);
 778         if (!ss->name) {
 779                 dso->load_errno = errno;
 780                 goto out_elf_end;
 781         }
 782
 783         ss->elf    = elf;
 784         ss->fd     = fd;
 785         ss->ehdr   = ehdr;
 786         ss->type   = type;
 787
 788         return 0;
 789
 790 out_elf_end:
 791         elf_end(elf);
 792 out_close:
 793         close(fd);
 794         return err;
 795 }
 796
 797 /**
 798  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 799  * @kmap: kernel maps and relocation reference symbol
 800  *
 801  * This function returns %true if we are dealing with the kernel maps and the
 802  * relocation reference symbol has not yet been found.  Otherwise %false is
 803  * returned.
 804  */
 805 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 806 {
 807         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 808                !kmap->ref_reloc_sym->unrelocated_addr;
 809 }
 810
 811 /**
 812  * ref_reloc - kernel relocation offset.
 813  * @kmap: kernel maps and relocation reference symbol
 814  *
 815  * This function returns the offset of kernel addresses as determined by using
 816  * the relocation reference symbol i.e. if the kernel has not been relocated
 817  * then the return value is zero.
 818  */
 819 static u64 ref_reloc(struct kmap *kmap)
 820 {
 821         if (kmap && kmap->ref_reloc_sym &&
 822             kmap->ref_reloc_sym->unrelocated_addr)
 823                 return kmap->ref_reloc_sym->addr -
 824                        kmap->ref_reloc_sym->unrelocated_addr;
 825         return 0;
 826 }
 827
 828 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 829                 GElf_Sym *sym __maybe_unused) { }
 830
 831 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 832                   struct symsrc *runtime_ss, int kmodule)
 833 {
 834         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 835         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 836         struct map *curr_map = map;
 837         struct dso *curr_dso = dso;
 838         Elf_Data *symstrs, *secstrs;
 839         uint32_t nr_syms;
 840         int err = -1;
 841         uint32_t idx;
 842         GElf_Ehdr ehdr;
 843         GElf_Shdr shdr;
 844         GElf_Shdr tshdr;
 845         Elf_Data *syms, *opddata = NULL;
 846         GElf_Sym sym;
 847         Elf_Scn *sec, *sec_strndx;
 848         Elf *elf;
 849         int nr = 0;
 850         bool remap_kernel = false, adjust_kernel_syms = false;
 851
 852         if (kmap && !kmaps)
 853                 return -1;
 854
 855         dso->symtab_type = syms_ss->type;
 856         dso->is_64_bit = syms_ss->is_64_bit;
 857         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 858
 859         /*
 860          * Modules may already have symbols from kallsyms, but those symbols
 861          * have the wrong values for the dso maps, so remove them.
 862          */
 863         if (kmodule && syms_ss->symtab)
 864                 symbols__delete(&dso->symbols[map->type]);
 865
 866         if (!syms_ss->symtab) {
 867                 /*
 868                  * If the vmlinux is stripped, fail so we will fall back
 869                  * to using kallsyms. The vmlinux runtime symbols aren't
 870                  * of much use.
 871                  */
 872                 if (dso->kernel)
 873                         goto out_elf_end;
 874
 875                 syms_ss->symtab  = syms_ss->dynsym;
 876                 syms_ss->symshdr = syms_ss->dynshdr;
 877         }
 878
 879         elf = syms_ss->elf;
 880         ehdr = syms_ss->ehdr;
 881         sec = syms_ss->symtab;
 882         shdr = syms_ss->symshdr;
 883
 884         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 885                                 ".text", NULL))
 886                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 887
 888         if (runtime_ss->opdsec)
 889                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 890
 891         syms = elf_getdata(sec, NULL);
 892         if (syms == NULL)
 893                 goto out_elf_end;
 894
 895         sec = elf_getscn(elf, shdr.sh_link);
 896         if (sec == NULL)
 897                 goto out_elf_end;
 898
 899         symstrs = elf_getdata(sec, NULL);
 900         if (symstrs == NULL)
 901                 goto out_elf_end;
 902
 903         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 904         if (sec_strndx == NULL)
 905                 goto out_elf_end;
 906
 907         secstrs = elf_getdata(sec_strndx, NULL);
 908         if (secstrs == NULL)
 909                 goto out_elf_end;
 910
 911         nr_syms = shdr.sh_size / shdr.sh_entsize;
 912
 913         memset(&sym, 0, sizeof(sym));
 914
 915         /*
 916          * The kernel relocation symbol is needed in advance in order to adjust
 917          * kernel maps correctly.
 918          */
 919         if (ref_reloc_sym_not_found(kmap)) {
 920                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 921                         const char *elf_name = elf_sym__name(&sym, symstrs);
 922
 923                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 924                                 continue;
 925                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 926                         map->reloc = kmap->ref_reloc_sym->addr -
 927                                      kmap->ref_reloc_sym->unrelocated_addr;
 928                         break;
 929                 }
 930         }
 931
 932         /*
 933          * Handle any relocation of vdso necessary because older kernels
 934          * attempted to prelink vdso to its virtual address.
 935          */
 936         if (dso__is_vdso(dso))
 937                 map->reloc = map->start - dso->text_offset;
 938
 939         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 940         /*
 941          * Initial kernel and module mappings do not map to the dso.  For
 942          * function mappings, flag the fixups.
 943          */
 944         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 945                 remap_kernel = true;
 946                 adjust_kernel_syms = dso->adjust_symbols;
 947         }
 948         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 949                 struct symbol *f;
 950                 const char *elf_name = elf_sym__name(&sym, symstrs);
 951                 char *demangled = NULL;
 952                 int is_label = elf_sym__is_label(&sym);
 953                 const char *section_name;
 954                 bool used_opd = false;
 955
 956                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 957                         continue;
 958
 959                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 960                  * don't identify functions, so will confuse the profile
 961                  * output: */
 962                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
 963                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
 964                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
 965                                 continue;
 966                 }
 967
 968                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 969                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 970                         u64 *opd = opddata->d_buf + offset;
 971                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 972                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 973                                         sym.st_value);
 974                         used_opd = true;
 975                 }
 976                 /*
 977                  * When loading symbols in a data mapping, ABS symbols (which
 978                  * has a value of SHN_ABS in its st_shndx) failed at
 979                  * elf_getscn().  And it marks the loading as a failure so
 980                  * already loaded symbols cannot be fixed up.
 981                  *
 982                  * I'm not sure what should be done. Just ignore them for now.
 983                  * - Namhyung Kim
 984                  */
 985                 if (sym.st_shndx == SHN_ABS)
 986                         continue;
 987
 988                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 989                 if (!sec)
 990                         goto out_elf_end;
 991
 992                 gelf_getshdr(sec, &shdr);
 993
 994                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 995                         continue;
 996
 997                 section_name = elf_sec__name(&shdr, secstrs);
 998
 999                 /* On ARM, symbols for thumb functions have 1 added to
1000                  * the symbol address as a flag - remove it */
1001                 if ((ehdr.e_machine == EM_ARM) &&
1002                     (map->type == MAP__FUNCTION) &&
1003                     (sym.st_value & 1))
1004                         --sym.st_value;
1005
1006                 if (dso->kernel || kmodule) {
1007                         char dso_name[PATH_MAX];
1008
1009                         /* Adjust symbol to map to file offset */
1010                         if (adjust_kernel_syms)
1011                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1012
1013                         if (strcmp(section_name,
1014                                    (curr_dso->short_name +
1015                                     dso->short_name_len)) == 0)
1016                                 goto new_symbol;
1017
1018                         if (strcmp(section_name, ".text") == 0) {
1019                                 /*
1020                                  * The initial kernel mapping is based on
1021                                  * kallsyms and identity maps.  Overwrite it to
1022                                  * map to the kernel dso.
1023                                  */
1024                                 if (remap_kernel && dso->kernel) {
1025                                         remap_kernel = false;
1026                                         map->start = shdr.sh_addr +
1027                                                      ref_reloc(kmap);
1028                                         map->end = map->start + shdr.sh_size;
1029                                         map->pgoff = shdr.sh_offset;
1030                                         map->map_ip = map__map_ip;
1031                                         map->unmap_ip = map__unmap_ip;
1032                                         /* Ensure maps are correctly ordered */
1033                                         if (kmaps) {
1034                                                 map__get(map);
1035                                                 map_groups__remove(kmaps, map);
1036                                                 map_groups__insert(kmaps, map);
1037                                                 map__put(map);
1038                                         }
1039                                 }
1040
1041                                 /*
1042                                  * The initial module mapping is based on
1043                                  * /proc/modules mapped to offset zero.
1044                                  * Overwrite it to map to the module dso.
1045                                  */
1046                                 if (remap_kernel && kmodule) {
1047                                         remap_kernel = false;
1048                                         map->pgoff = shdr.sh_offset;
1049                                 }
1050
1051                                 curr_map = map;
1052                                 curr_dso = dso;
1053                                 goto new_symbol;
1054                         }
1055
1056                         if (!kmap)
1057                                 goto new_symbol;
1058
1059                         snprintf(dso_name, sizeof(dso_name),
1060                                  "%s%s", dso->short_name, section_name);
1061
1062                         curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1063                         if (curr_map == NULL) {
1064                                 u64 start = sym.st_value;
1065
1066                                 if (kmodule)
1067                                         start += map->start + shdr.sh_offset;
1068
1069                                 curr_dso = dso__new(dso_name);
1070                                 if (curr_dso == NULL)
1071                                         goto out_elf_end;
1072                                 curr_dso->kernel = dso->kernel;
1073                                 curr_dso->long_name = dso->long_name;
1074                                 curr_dso->long_name_len = dso->long_name_len;
1075                                 curr_map = map__new2(start, curr_dso,
1076                                                      map->type);
1077                                 dso__put(curr_dso);
1078                                 if (curr_map == NULL) {
1079                                         goto out_elf_end;
1080                                 }
1081                                 if (adjust_kernel_syms) {
1082                                         curr_map->start = shdr.sh_addr +
1083                                                           ref_reloc(kmap);
1084                                         curr_map->end = curr_map->start +
1085                                                         shdr.sh_size;
1086                                         curr_map->pgoff = shdr.sh_offset;
1087                                 } else {
1088                                         curr_map->map_ip = identity__map_ip;
1089                                         curr_map->unmap_ip = identity__map_ip;
1090                                 }
1091                                 curr_dso->symtab_type = dso->symtab_type;
1092                                 map_groups__insert(kmaps, curr_map);
1093                                 /*
1094                                  * Add it before we drop the referece to curr_map,
1095                                  * i.e. while we still are sure to have a reference
1096                                  * to this DSO via curr_map->dso.
1097                                  */
1098                                 dsos__add(&map->groups->machine->dsos, curr_dso);
1099                                 /* kmaps already got it */
1100                                 map__put(curr_map);
1101                                 dso__set_loaded(curr_dso, map->type);
1102                         } else
1103                                 curr_dso = curr_map->dso;
1104
1105                         goto new_symbol;
1106                 }
1107
1108                 if ((used_opd && runtime_ss->adjust_symbols)
1109                                 || (!used_opd && syms_ss->adjust_symbols)) {
1110                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1111                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1112                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1113                                   (u64)shdr.sh_offset);
1114                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1115                 }
1116 new_symbol:
1117                 demangled = demangle_sym(dso, kmodule, elf_name);
1118                 if (demangled != NULL)
1119                         elf_name = demangled;
1120
1121                 f = symbol__new(sym.st_value, sym.st_size,
1122                                 GELF_ST_BIND(sym.st_info), elf_name);
1123                 free(demangled);
1124                 if (!f)
1125                         goto out_elf_end;
1126
1127                 arch__sym_update(f, &sym);
1128
1129                 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1130                 nr++;
1131         }
1132
1133         /*
1134          * For misannotated, zeroed, ASM function sizes.
1135          */
1136         if (nr > 0) {
1137                 symbols__fixup_end(&dso->symbols[map->type]);
1138                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1139                 if (kmap) {
1140                         /*
1141                          * We need to fixup this here too because we create new
1142                          * maps here, for things like vsyscall sections.
1143                          */
1144                         __map_groups__fixup_end(kmaps, map->type);
1145                 }
1146         }
1147         err = nr;
1148 out_elf_end:
1149         return err;
1150 }
1151
1152 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1153 {
1154         GElf_Phdr phdr;
1155         size_t i, phdrnum;
1156         int err;
1157         u64 sz;
1158
1159         if (elf_getphdrnum(elf, &phdrnum))
1160                 return -1;
1161
1162         for (i = 0; i < phdrnum; i++) {
1163                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1164                         return -1;
1165                 if (phdr.p_type != PT_LOAD)
1166                         continue;
1167                 if (exe) {
1168                         if (!(phdr.p_flags & PF_X))
1169                                 continue;
1170                 } else {
1171                         if (!(phdr.p_flags & PF_R))
1172                                 continue;
1173                 }
1174                 sz = min(phdr.p_memsz, phdr.p_filesz);
1175                 if (!sz)
1176                         continue;
1177                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1178                 if (err)
1179                         return err;
1180         }
1181         return 0;
1182 }
1183
1184 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1185                     bool *is_64_bit)
1186 {
1187         int err;
1188         Elf *elf;
1189
1190         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1191         if (elf == NULL)
1192                 return -1;
1193
1194         if (is_64_bit)
1195                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1196
1197         err = elf_read_maps(elf, exe, mapfn, data);
1198
1199         elf_end(elf);
1200         return err;
1201 }
1202
1203 enum dso_type dso__type_fd(int fd)
1204 {
1205         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1206         GElf_Ehdr ehdr;
1207         Elf_Kind ek;
1208         Elf *elf;
1209
1210         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1211         if (elf == NULL)
1212                 goto out;
1213
1214         ek = elf_kind(elf);
1215         if (ek != ELF_K_ELF)
1216                 goto out_end;
1217
1218         if (gelf_getclass(elf) == ELFCLASS64) {
1219                 dso_type = DSO__TYPE_64BIT;
1220                 goto out_end;
1221         }
1222
1223         if (gelf_getehdr(elf, &ehdr) == NULL)
1224                 goto out_end;
1225
1226         if (ehdr.e_machine == EM_X86_64)
1227                 dso_type = DSO__TYPE_X32BIT;
1228         else
1229                 dso_type = DSO__TYPE_32BIT;
1230 out_end:
1231         elf_end(elf);
1232 out:
1233         return dso_type;
1234 }
1235
1236 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1237 {
1238         ssize_t r;
1239         size_t n;
1240         int err = -1;
1241         char *buf = malloc(page_size);
1242
1243         if (buf == NULL)
1244                 return -1;
1245
1246         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1247                 goto out;
1248
1249         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1250                 goto out;
1251
1252         while (len) {
1253                 n = page_size;
1254                 if (len < n)
1255                         n = len;
1256                 /* Use read because mmap won't work on proc files */
1257                 r = read(from, buf, n);
1258                 if (r < 0)
1259                         goto out;
1260                 if (!r)
1261                         break;
1262                 n = r;
1263                 r = write(to, buf, n);
1264                 if (r < 0)
1265                         goto out;
1266                 if ((size_t)r != n)
1267                         goto out;
1268                 len -= n;
1269         }
1270
1271         err = 0;
1272 out:
1273         free(buf);
1274         return err;
1275 }
1276
1277 struct kcore {
1278         int fd;
1279         int elfclass;
1280         Elf *elf;
1281         GElf_Ehdr ehdr;
1282 };
1283
1284 static int kcore__open(struct kcore *kcore, const char *filename)
1285 {
1286         GElf_Ehdr *ehdr;
1287
1288         kcore->fd = open(filename, O_RDONLY);
1289         if (kcore->fd == -1)
1290                 return -1;
1291
1292         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1293         if (!kcore->elf)
1294                 goto out_close;
1295
1296         kcore->elfclass = gelf_getclass(kcore->elf);
1297         if (kcore->elfclass == ELFCLASSNONE)
1298                 goto out_end;
1299
1300         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1301         if (!ehdr)
1302                 goto out_end;
1303
1304         return 0;
1305
1306 out_end:
1307         elf_end(kcore->elf);
1308 out_close:
1309         close(kcore->fd);
1310         return -1;
1311 }
1312
1313 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1314                        bool temp)
1315 {
1316         kcore->elfclass = elfclass;
1317
1318         if (temp)
1319                 kcore->fd = mkstemp(filename);
1320         else
1321                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1322         if (kcore->fd == -1)
1323                 return -1;
1324
1325         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1326         if (!kcore->elf)
1327                 goto out_close;
1328
1329         if (!gelf_newehdr(kcore->elf, elfclass))
1330                 goto out_end;
1331
1332         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1333
1334         return 0;
1335
1336 out_end:
1337         elf_end(kcore->elf);
1338 out_close:
1339         close(kcore->fd);
1340         unlink(filename);
1341         return -1;
1342 }
1343
1344 static void kcore__close(struct kcore *kcore)
1345 {
1346         elf_end(kcore->elf);
1347         close(kcore->fd);
1348 }
1349
1350 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1351 {
1352         GElf_Ehdr *ehdr = &to->ehdr;
1353         GElf_Ehdr *kehdr = &from->ehdr;
1354
1355         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1356         ehdr->e_type      = kehdr->e_type;
1357         ehdr->e_machine   = kehdr->e_machine;
1358         ehdr->e_version   = kehdr->e_version;
1359         ehdr->e_entry     = 0;
1360         ehdr->e_shoff     = 0;
1361         ehdr->e_flags     = kehdr->e_flags;
1362         ehdr->e_phnum     = count;
1363         ehdr->e_shentsize = 0;
1364         ehdr->e_shnum     = 0;
1365         ehdr->e_shstrndx  = 0;
1366
1367         if (from->elfclass == ELFCLASS32) {
1368                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1369                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1370                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1371         } else {
1372                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1373                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1374                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1375         }
1376
1377         if (!gelf_update_ehdr(to->elf, ehdr))
1378                 return -1;
1379
1380         if (!gelf_newphdr(to->elf, count))
1381                 return -1;
1382
1383         return 0;
1384 }
1385
1386 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1387                            u64 addr, u64 len)
1388 {
1389         GElf_Phdr phdr = {
1390                 .p_type         = PT_LOAD,
1391                 .p_flags        = PF_R | PF_W | PF_X,
1392                 .p_offset       = offset,
1393                 .p_vaddr        = addr,
1394                 .p_paddr        = 0,
1395                 .p_filesz       = len,
1396                 .p_memsz        = len,
1397                 .p_align        = page_size,
1398         };
1399
1400         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1401                 return -1;
1402
1403         return 0;
1404 }
1405
1406 static off_t kcore__write(struct kcore *kcore)
1407 {
1408         return elf_update(kcore->elf, ELF_C_WRITE);
1409 }
1410
1411 struct phdr_data {
1412         off_t offset;
1413         u64 addr;
1414         u64 len;
1415 };
1416
1417 struct kcore_copy_info {
1418         u64 stext;
1419         u64 etext;
1420         u64 first_symbol;
1421         u64 last_symbol;
1422         u64 first_module;
1423         u64 first_module_symbol;
1424         u64 last_module_symbol;
1425         struct phdr_data kernel_map;
1426         struct phdr_data modules_map;
1427 };
1428
1429 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1430                                         u64 start)
1431 {
1432         struct kcore_copy_info *kci = arg;
1433
1434         if (!symbol_type__is_a(type, MAP__FUNCTION))
1435                 return 0;
1436
1437         if (strchr(name, '[')) {
1438                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1439                         kci->first_module_symbol = start;
1440                 if (start > kci->last_module_symbol)
1441                         kci->last_module_symbol = start;
1442                 return 0;
1443         }
1444
1445         if (!kci->first_symbol || start < kci->first_symbol)
1446                 kci->first_symbol = start;
1447
1448         if (!kci->last_symbol || start > kci->last_symbol)
1449                 kci->last_symbol = start;
1450
1451         if (!strcmp(name, "_stext")) {
1452                 kci->stext = start;
1453                 return 0;
1454         }
1455
1456         if (!strcmp(name, "_etext")) {
1457                 kci->etext = start;
1458                 return 0;
1459         }
1460
1461         return 0;
1462 }
1463
1464 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1465                                       const char *dir)
1466 {
1467         char kallsyms_filename[PATH_MAX];
1468
1469         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1470
1471         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1472                 return -1;
1473
1474         if (kallsyms__parse(kallsyms_filename, kci,
1475                             kcore_copy__process_kallsyms) < 0)
1476                 return -1;
1477
1478         return 0;
1479 }
1480
1481 static int kcore_copy__process_modules(void *arg,
1482                                        const char *name __maybe_unused,
1483                                        u64 start, u64 size __maybe_unused)
1484 {
1485         struct kcore_copy_info *kci = arg;
1486
1487         if (!kci->first_module || start < kci->first_module)
1488                 kci->first_module = start;
1489
1490         return 0;
1491 }
1492
1493 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1494                                      const char *dir)
1495 {
1496         char modules_filename[PATH_MAX];
1497
1498         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1499
1500         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1501                 return -1;
1502
1503         if (modules__parse(modules_filename, kci,
1504                            kcore_copy__process_modules) < 0)
1505                 return -1;
1506
1507         return 0;
1508 }
1509
1510 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1511                             u64 s, u64 e)
1512 {
1513         if (p->addr || s < start || s >= end)
1514                 return;
1515
1516         p->addr = s;
1517         p->offset = (s - start) + pgoff;
1518         p->len = e < end ? e - s : end - s;
1519 }
1520
1521 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1522 {
1523         struct kcore_copy_info *kci = data;
1524         u64 end = start + len;
1525
1526         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1527                         kci->etext);
1528
1529         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1530                         kci->last_module_symbol);
1531
1532         return 0;
1533 }
1534
1535 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1536 {
1537         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1538                 return -1;
1539
1540         return 0;
1541 }
1542
1543 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1544                                  Elf *elf)
1545 {
1546         if (kcore_copy__parse_kallsyms(kci, dir))
1547                 return -1;
1548
1549         if (kcore_copy__parse_modules(kci, dir))
1550                 return -1;
1551
1552         if (kci->stext)
1553                 kci->stext = round_down(kci->stext, page_size);
1554         else
1555                 kci->stext = round_down(kci->first_symbol, page_size);
1556
1557         if (kci->etext) {
1558                 kci->etext = round_up(kci->etext, page_size);
1559         } else if (kci->last_symbol) {
1560                 kci->etext = round_up(kci->last_symbol, page_size);
1561                 kci->etext += page_size;
1562         }
1563
1564         if (kci->first_module_symbol &&
1565             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1566                 kci->first_module = kci->first_module_symbol;
1567
1568         kci->first_module = round_down(kci->first_module, page_size);
1569
1570         if (kci->last_module_symbol) {
1571                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1572                                                    page_size);
1573                 kci->last_module_symbol += page_size;
1574         }
1575
1576         if (!kci->stext || !kci->etext)
1577                 return -1;
1578
1579         if (kci->first_module && !kci->last_module_symbol)
1580                 return -1;
1581
1582         return kcore_copy__read_maps(kci, elf);
1583 }
1584
1585 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1586                                  const char *name)
1587 {
1588         char from_filename[PATH_MAX];
1589         char to_filename[PATH_MAX];
1590
1591         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1592         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1593
1594         return copyfile_mode(from_filename, to_filename, 0400);
1595 }
1596
1597 static int kcore_copy__unlink(const char *dir, const char *name)
1598 {
1599         char filename[PATH_MAX];
1600
1601         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1602
1603         return unlink(filename);
1604 }
1605
1606 static int kcore_copy__compare_fds(int from, int to)
1607 {
1608         char *buf_from;
1609         char *buf_to;
1610         ssize_t ret;
1611         size_t len;
1612         int err = -1;
1613
1614         buf_from = malloc(page_size);
1615         buf_to = malloc(page_size);
1616         if (!buf_from || !buf_to)
1617                 goto out;
1618
1619         while (1) {
1620                 /* Use read because mmap won't work on proc files */
1621                 ret = read(from, buf_from, page_size);
1622                 if (ret < 0)
1623                         goto out;
1624
1625                 if (!ret)
1626                         break;
1627
1628                 len = ret;
1629
1630                 if (readn(to, buf_to, len) != (int)len)
1631                         goto out;
1632
1633                 if (memcmp(buf_from, buf_to, len))
1634                         goto out;
1635         }
1636
1637         err = 0;
1638 out:
1639         free(buf_to);
1640         free(buf_from);
1641         return err;
1642 }
1643
1644 static int kcore_copy__compare_files(const char *from_filename,
1645                                      const char *to_filename)
1646 {
1647         int from, to, err = -1;
1648
1649         from = open(from_filename, O_RDONLY);
1650         if (from < 0)
1651                 return -1;
1652
1653         to = open(to_filename, O_RDONLY);
1654         if (to < 0)
1655                 goto out_close_from;
1656
1657         err = kcore_copy__compare_fds(from, to);
1658
1659         close(to);
1660 out_close_from:
1661         close(from);
1662         return err;
1663 }
1664
1665 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1666                                     const char *name)
1667 {
1668         char from_filename[PATH_MAX];
1669         char to_filename[PATH_MAX];
1670
1671         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1672         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1673
1674         return kcore_copy__compare_files(from_filename, to_filename);
1675 }
1676
1677 /**
1678  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1679  * @from_dir: from directory
1680  * @to_dir: to directory
1681  *
1682  * This function copies kallsyms, modules and kcore files from one directory to
1683  * another.  kallsyms and modules are copied entirely.  Only code segments are
1684  * copied from kcore.  It is assumed that two segments suffice: one for the
1685  * kernel proper and one for all the modules.  The code segments are determined
1686  * from kallsyms and modules files.  The kernel map starts at _stext or the
1687  * lowest function symbol, and ends at _etext or the highest function symbol.
1688  * The module map starts at the lowest module address and ends at the highest
1689  * module symbol.  Start addresses are rounded down to the nearest page.  End
1690  * addresses are rounded up to the nearest page.  An extra page is added to the
1691  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1692  * symbol too.  Because it contains only code sections, the resulting kcore is
1693  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1694  * is not the same for the kernel map and the modules map.  That happens because
1695  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1696  * kallsyms and modules files are compared with their copies to check that
1697  * modules have not been loaded or unloaded while the copies were taking place.
1698  *
1699  * Return: %0 on success, %-1 on failure.
1700  */
1701 int kcore_copy(const char *from_dir, const char *to_dir)
1702 {
1703         struct kcore kcore;
1704         struct kcore extract;
1705         size_t count = 2;
1706         int idx = 0, err = -1;
1707         off_t offset = page_size, sz, modules_offset = 0;
1708         struct kcore_copy_info kci = { .stext = 0, };
1709         char kcore_filename[PATH_MAX];
1710         char extract_filename[PATH_MAX];
1711
1712         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1713                 return -1;
1714
1715         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1716                 goto out_unlink_kallsyms;
1717
1718         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1719         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1720
1721         if (kcore__open(&kcore, kcore_filename))
1722                 goto out_unlink_modules;
1723
1724         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1725                 goto out_kcore_close;
1726
1727         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1728                 goto out_kcore_close;
1729
1730         if (!kci.modules_map.addr)
1731                 count -= 1;
1732
1733         if (kcore__copy_hdr(&kcore, &extract, count))
1734                 goto out_extract_close;
1735
1736         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1737                             kci.kernel_map.len))
1738                 goto out_extract_close;
1739
1740         if (kci.modules_map.addr) {
1741                 modules_offset = offset + kci.kernel_map.len;
1742                 if (kcore__add_phdr(&extract, idx, modules_offset,
1743                                     kci.modules_map.addr, kci.modules_map.len))
1744                         goto out_extract_close;
1745         }
1746
1747         sz = kcore__write(&extract);
1748         if (sz < 0 || sz > offset)
1749                 goto out_extract_close;
1750
1751         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1752                        kci.kernel_map.len))
1753                 goto out_extract_close;
1754
1755         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1756                                          extract.fd, modules_offset,
1757                                          kci.modules_map.len))
1758                 goto out_extract_close;
1759
1760         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1761                 goto out_extract_close;
1762
1763         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1764                 goto out_extract_close;
1765
1766         err = 0;
1767
1768 out_extract_close:
1769         kcore__close(&extract);
1770         if (err)
1771                 unlink(extract_filename);
1772 out_kcore_close:
1773         kcore__close(&kcore);
1774 out_unlink_modules:
1775         if (err)
1776                 kcore_copy__unlink(to_dir, "modules");
1777 out_unlink_kallsyms:
1778         if (err)
1779                 kcore_copy__unlink(to_dir, "kallsyms");
1780
1781         return err;
1782 }
1783
1784 int kcore_extract__create(struct kcore_extract *kce)
1785 {
1786         struct kcore kcore;
1787         struct kcore extract;
1788         size_t count = 1;
1789         int idx = 0, err = -1;
1790         off_t offset = page_size, sz;
1791
1792         if (kcore__open(&kcore, kce->kcore_filename))
1793                 return -1;
1794
1795         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1796         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1797                 goto out_kcore_close;
1798
1799         if (kcore__copy_hdr(&kcore, &extract, count))
1800                 goto out_extract_close;
1801
1802         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1803                 goto out_extract_close;
1804
1805         sz = kcore__write(&extract);
1806         if (sz < 0 || sz > offset)
1807                 goto out_extract_close;
1808
1809         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1810                 goto out_extract_close;
1811
1812         err = 0;
1813
1814 out_extract_close:
1815         kcore__close(&extract);
1816         if (err)
1817                 unlink(kce->extract_filename);
1818 out_kcore_close:
1819         kcore__close(&kcore);
1820
1821         return err;
1822 }
1823
1824 void kcore_extract__delete(struct kcore_extract *kce)
1825 {
1826         unlink(kce->extract_filename);
1827 }
1828
1829 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1830 /**
1831  * populate_sdt_note : Parse raw data and identify SDT note
1832  * @elf: elf of the opened file
1833  * @data: raw data of a section with description offset applied
1834  * @len: note description size
1835  * @type: type of the note
1836  * @sdt_notes: List to add the SDT note
1837  *
1838  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1839  * if its an SDT note, it appends to @sdt_notes list.
1840  */
1841 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1842                              struct list_head *sdt_notes)
1843 {
1844         const char *provider, *name, *args;
1845         struct sdt_note *tmp = NULL;
1846         GElf_Ehdr ehdr;
1847         GElf_Addr base_off = 0;
1848         GElf_Shdr shdr;
1849         int ret = -EINVAL;
1850
1851         union {
1852                 Elf64_Addr a64[NR_ADDR];
1853                 Elf32_Addr a32[NR_ADDR];
1854         } buf;
1855
1856         Elf_Data dst = {
1857                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1858                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1859                 .d_off = 0, .d_align = 0
1860         };
1861         Elf_Data src = {
1862                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1863                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1864                 .d_align = 0
1865         };
1866
1867         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1868         if (!tmp) {
1869                 ret = -ENOMEM;
1870                 goto out_err;
1871         }
1872
1873         INIT_LIST_HEAD(&tmp->note_list);
1874
1875         if (len < dst.d_size + 3)
1876                 goto out_free_note;
1877
1878         /* Translation from file representation to memory representation */
1879         if (gelf_xlatetom(*elf, &dst, &src,
1880                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1881                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1882                 goto out_free_note;
1883         }
1884
1885         /* Populate the fields of sdt_note */
1886         provider = data + dst.d_size;
1887
1888         name = (const char *)memchr(provider, '\0', data + len - provider);
1889         if (name++ == NULL)
1890                 goto out_free_note;
1891
1892         tmp->provider = strdup(provider);
1893         if (!tmp->provider) {
1894                 ret = -ENOMEM;
1895                 goto out_free_note;
1896         }
1897         tmp->name = strdup(name);
1898         if (!tmp->name) {
1899                 ret = -ENOMEM;
1900                 goto out_free_prov;
1901         }
1902
1903         args = memchr(name, '\0', data + len - name);
1904
1905         /*
1906          * There is no argument if:
1907          * - We reached the end of the note;
1908          * - There is not enough room to hold a potential string;
1909          * - The argument string is empty or just contains ':'.
1910          */
1911         if (args == NULL || data + len - args < 2 ||
1912                 args[1] == ':' || args[1] == '\0')
1913                 tmp->args = NULL;
1914         else {
1915                 tmp->args = strdup(++args);
1916                 if (!tmp->args) {
1917                         ret = -ENOMEM;
1918                         goto out_free_name;
1919                 }
1920         }
1921
1922         if (gelf_getclass(*elf) == ELFCLASS32) {
1923                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1924                 tmp->bit32 = true;
1925         } else {
1926                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1927                 tmp->bit32 = false;
1928         }
1929
1930         if (!gelf_getehdr(*elf, &ehdr)) {
1931                 pr_debug("%s : cannot get elf header.\n", __func__);
1932                 ret = -EBADF;
1933                 goto out_free_args;
1934         }
1935
1936         /* Adjust the prelink effect :
1937          * Find out the .stapsdt.base section.
1938          * This scn will help us to handle prelinking (if present).
1939          * Compare the retrieved file offset of the base section with the
1940          * base address in the description of the SDT note. If its different,
1941          * then accordingly, adjust the note location.
1942          */
1943         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1944                 base_off = shdr.sh_offset;
1945                 if (base_off) {
1946                         if (tmp->bit32)
1947                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1948                                         tmp->addr.a32[1];
1949                         else
1950                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1951                                         tmp->addr.a64[1];
1952                 }
1953         }
1954
1955         list_add_tail(&tmp->note_list, sdt_notes);
1956         return 0;
1957
1958 out_free_args:
1959         free(tmp->args);
1960 out_free_name:
1961         free(tmp->name);
1962 out_free_prov:
1963         free(tmp->provider);
1964 out_free_note:
1965         free(tmp);
1966 out_err:
1967         return ret;
1968 }
1969
1970 /**
1971  * construct_sdt_notes_list : constructs a list of SDT notes
1972  * @elf : elf to look into
1973  * @sdt_notes : empty list_head
1974  *
1975  * Scans the sections in 'elf' for the section
1976  * .note.stapsdt. It, then calls populate_sdt_note to find
1977  * out the SDT events and populates the 'sdt_notes'.
1978  */
1979 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1980 {
1981         GElf_Ehdr ehdr;
1982         Elf_Scn *scn = NULL;
1983         Elf_Data *data;
1984         GElf_Shdr shdr;
1985         size_t shstrndx, next;
1986         GElf_Nhdr nhdr;
1987         size_t name_off, desc_off, offset;
1988         int ret = 0;
1989
1990         if (gelf_getehdr(elf, &ehdr) == NULL) {
1991                 ret = -EBADF;
1992                 goto out_ret;
1993         }
1994         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1995                 ret = -EBADF;
1996                 goto out_ret;
1997         }
1998
1999         /* Look for the required section */
2000         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2001         if (!scn) {
2002                 ret = -ENOENT;
2003                 goto out_ret;
2004         }
2005
2006         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2007                 ret = -ENOENT;
2008                 goto out_ret;
2009         }
2010
2011         data = elf_getdata(scn, NULL);
2012
2013         /* Get the SDT notes */
2014         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2015                                               &desc_off)) > 0; offset = next) {
2016                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2017                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2018                             sizeof(SDT_NOTE_NAME))) {
2019                         /* Check the type of the note */
2020                         if (nhdr.n_type != SDT_NOTE_TYPE)
2021                                 goto out_ret;
2022
2023                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2024                                                 nhdr.n_descsz, sdt_notes);
2025                         if (ret < 0)
2026                                 goto out_ret;
2027                 }
2028         }
2029         if (list_empty(sdt_notes))
2030                 ret = -ENOENT;
2031
2032 out_ret:
2033         return ret;
2034 }
2035
2036 /**
2037  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2038  * @head : empty list_head
2039  * @target : file to find SDT notes from
2040  *
2041  * This opens the file, initializes
2042  * the ELF and then calls construct_sdt_notes_list.
2043  */
2044 int get_sdt_note_list(struct list_head *head, const char *target)
2045 {
2046         Elf *elf;
2047         int fd, ret;
2048
2049         fd = open(target, O_RDONLY);
2050         if (fd < 0)
2051                 return -EBADF;
2052
2053         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2054         if (!elf) {
2055                 ret = -EBADF;
2056                 goto out_close;
2057         }
2058         ret = construct_sdt_notes_list(elf, head);
2059         elf_end(elf);
2060 out_close:
2061         close(fd);
2062         return ret;
2063 }
2064
2065 /**
2066  * cleanup_sdt_note_list : free the sdt notes' list
2067  * @sdt_notes: sdt notes' list
2068  *
2069  * Free up the SDT notes in @sdt_notes.
2070  * Returns the number of SDT notes free'd.
2071  */
2072 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2073 {
2074         struct sdt_note *tmp, *pos;
2075         int nr_free = 0;
2076
2077         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2078                 list_del(&pos->note_list);
2079                 free(pos->name);
2080                 free(pos->provider);
2081                 free(pos);
2082                 nr_free++;
2083         }
2084         return nr_free;
2085 }
2086
2087 /**
2088  * sdt_notes__get_count: Counts the number of sdt events
2089  * @start: list_head to sdt_notes list
2090  *
2091  * Returns the number of SDT notes in a list
2092  */
2093 int sdt_notes__get_count(struct list_head *start)
2094 {
2095         struct sdt_note *sdt_ptr;
2096         int count = 0;
2097
2098         list_for_each_entry(sdt_ptr, start, note_list)
2099                 count++;
2100         return count;
2101 }
2102 #endif
2103
2104 void symbol__elf_init(void)
2105 {
2106         elf_version(EV_CURRENT);
2107 }