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                 case EM_SPARC:
 328                         plt_header_size = 48;
 329                         plt_entry_size = 12;
 330                         break;
 331
 332                 case EM_SPARCV9:
 333                         plt_header_size = 128;
 334                         plt_entry_size = 32;
 335                         break;
 336
 337                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 338                         plt_header_size = shdr_plt.sh_entsize;
 339                         plt_entry_size = shdr_plt.sh_entsize;
 340                         break;
 341         }
 342         plt_offset += plt_header_size;
 343
 344         if (shdr_rel_plt.sh_type == SHT_RELA) {
 345                 GElf_Rela pos_mem, *pos;
 346
 347                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 348                                            nr_rel_entries) {
 349                         const char *elf_name = NULL;
 350                         char *demangled = NULL;
 351                         symidx = GELF_R_SYM(pos->r_info);
 352                         gelf_getsym(syms, symidx, &sym);
 353
 354                         elf_name = elf_sym__name(&sym, symstrs);
 355                         demangled = demangle_sym(dso, 0, elf_name);
 356                         if (demangled != NULL)
 357                                 elf_name = demangled;
 358                         snprintf(sympltname, sizeof(sympltname),
 359                                  "%s@plt", elf_name);
 360                         free(demangled);
 361
 362                         f = symbol__new(plt_offset, plt_entry_size,
 363                                         STB_GLOBAL, STT_FUNC, sympltname);
 364                         if (!f)
 365                                 goto out_elf_end;
 366
 367                         plt_offset += plt_entry_size;
 368                         symbols__insert(&dso->symbols, f);
 369                         ++nr;
 370                 }
 371         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 372                 GElf_Rel pos_mem, *pos;
 373                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 374                                           nr_rel_entries) {
 375                         const char *elf_name = NULL;
 376                         char *demangled = NULL;
 377                         symidx = GELF_R_SYM(pos->r_info);
 378                         gelf_getsym(syms, symidx, &sym);
 379
 380                         elf_name = elf_sym__name(&sym, symstrs);
 381                         demangled = demangle_sym(dso, 0, elf_name);
 382                         if (demangled != NULL)
 383                                 elf_name = demangled;
 384                         snprintf(sympltname, sizeof(sympltname),
 385                                  "%s@plt", elf_name);
 386                         free(demangled);
 387
 388                         f = symbol__new(plt_offset, plt_entry_size,
 389                                         STB_GLOBAL, STT_FUNC, sympltname);
 390                         if (!f)
 391                                 goto out_elf_end;
 392
 393                         plt_offset += plt_entry_size;
 394                         symbols__insert(&dso->symbols, f);
 395                         ++nr;
 396                 }
 397         }
 398
 399         err = 0;
 400 out_elf_end:
 401         if (err == 0)
 402                 return nr;
 403         pr_debug("%s: problems reading %s PLT info.\n",
 404                  __func__, dso->long_name);
 405         return 0;
 406 }
 407
 408 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 409 {
 410         return demangle_sym(dso, kmodule, elf_name);
 411 }
 412
 413 /*
 414  * Align offset to 4 bytes as needed for note name and descriptor data.
 415  */
 416 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 417
 418 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 419 {
 420         int err = -1;
 421         GElf_Ehdr ehdr;
 422         GElf_Shdr shdr;
 423         Elf_Data *data;
 424         Elf_Scn *sec;
 425         Elf_Kind ek;
 426         void *ptr;
 427
 428         if (size < BUILD_ID_SIZE)
 429                 goto out;
 430
 431         ek = elf_kind(elf);
 432         if (ek != ELF_K_ELF)
 433                 goto out;
 434
 435         if (gelf_getehdr(elf, &ehdr) == NULL) {
 436                 pr_err("%s: cannot get elf header.\n", __func__);
 437                 goto out;
 438         }
 439
 440         /*
 441          * Check following sections for notes:
 442          *   '.note.gnu.build-id'
 443          *   '.notes'
 444          *   '.note' (VDSO specific)
 445          */
 446         do {
 447                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 448                                           ".note.gnu.build-id", NULL);
 449                 if (sec)
 450                         break;
 451
 452                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 453                                           ".notes", NULL);
 454                 if (sec)
 455                         break;
 456
 457                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 458                                           ".note", NULL);
 459                 if (sec)
 460                         break;
 461
 462                 return err;
 463
 464         } while (0);
 465
 466         data = elf_getdata(sec, NULL);
 467         if (data == NULL)
 468                 goto out;
 469
 470         ptr = data->d_buf;
 471         while (ptr < (data->d_buf + data->d_size)) {
 472                 GElf_Nhdr *nhdr = ptr;
 473                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 474                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 475                 const char *name;
 476
 477                 ptr += sizeof(*nhdr);
 478                 name = ptr;
 479                 ptr += namesz;
 480                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 481                     nhdr->n_namesz == sizeof("GNU")) {
 482                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 483                                 size_t sz = min(size, descsz);
 484                                 memcpy(bf, ptr, sz);
 485                                 memset(bf + sz, 0, size - sz);
 486                                 err = descsz;
 487                                 break;
 488                         }
 489                 }
 490                 ptr += descsz;
 491         }
 492
 493 out:
 494         return err;
 495 }
 496
 497 int filename__read_build_id(const char *filename, void *bf, size_t size)
 498 {
 499         int fd, err = -1;
 500         Elf *elf;
 501
 502         if (size < BUILD_ID_SIZE)
 503                 goto out;
 504
 505         fd = open(filename, O_RDONLY);
 506         if (fd < 0)
 507                 goto out;
 508
 509         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 510         if (elf == NULL) {
 511                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 512                 goto out_close;
 513         }
 514
 515         err = elf_read_build_id(elf, bf, size);
 516
 517         elf_end(elf);
 518 out_close:
 519         close(fd);
 520 out:
 521         return err;
 522 }
 523
 524 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 525 {
 526         int fd, err = -1;
 527
 528         if (size < BUILD_ID_SIZE)
 529                 goto out;
 530
 531         fd = open(filename, O_RDONLY);
 532         if (fd < 0)
 533                 goto out;
 534
 535         while (1) {
 536                 char bf[BUFSIZ];
 537                 GElf_Nhdr nhdr;
 538                 size_t namesz, descsz;
 539
 540                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 541                         break;
 542
 543                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 544                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 545                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 546                     nhdr.n_namesz == sizeof("GNU")) {
 547                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 548                                 break;
 549                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 550                                 size_t sz = min(descsz, size);
 551                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 552                                         memset(build_id + sz, 0, size - sz);
 553                                         err = 0;
 554                                         break;
 555                                 }
 556                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 557                                 break;
 558                 } else {
 559                         int n = namesz + descsz;
 560
 561                         if (n > (int)sizeof(bf)) {
 562                                 n = sizeof(bf);
 563                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 564                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 565                         }
 566                         if (read(fd, bf, n) != n)
 567                                 break;
 568                 }
 569         }
 570         close(fd);
 571 out:
 572         return err;
 573 }
 574
 575 int filename__read_debuglink(const char *filename, char *debuglink,
 576                              size_t size)
 577 {
 578         int fd, err = -1;
 579         Elf *elf;
 580         GElf_Ehdr ehdr;
 581         GElf_Shdr shdr;
 582         Elf_Data *data;
 583         Elf_Scn *sec;
 584         Elf_Kind ek;
 585
 586         fd = open(filename, O_RDONLY);
 587         if (fd < 0)
 588                 goto out;
 589
 590         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 591         if (elf == NULL) {
 592                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 593                 goto out_close;
 594         }
 595
 596         ek = elf_kind(elf);
 597         if (ek != ELF_K_ELF)
 598                 goto out_elf_end;
 599
 600         if (gelf_getehdr(elf, &ehdr) == NULL) {
 601                 pr_err("%s: cannot get elf header.\n", __func__);
 602                 goto out_elf_end;
 603         }
 604
 605         sec = elf_section_by_name(elf, &ehdr, &shdr,
 606                                   ".gnu_debuglink", NULL);
 607         if (sec == NULL)
 608                 goto out_elf_end;
 609
 610         data = elf_getdata(sec, NULL);
 611         if (data == NULL)
 612                 goto out_elf_end;
 613
 614         /* the start of this section is a zero-terminated string */
 615         strncpy(debuglink, data->d_buf, size);
 616
 617         err = 0;
 618
 619 out_elf_end:
 620         elf_end(elf);
 621 out_close:
 622         close(fd);
 623 out:
 624         return err;
 625 }
 626
 627 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 628 {
 629         static unsigned int const endian = 1;
 630
 631         dso->needs_swap = DSO_SWAP__NO;
 632
 633         switch (eidata) {
 634         case ELFDATA2LSB:
 635                 /* We are big endian, DSO is little endian. */
 636                 if (*(unsigned char const *)&endian != 1)
 637                         dso->needs_swap = DSO_SWAP__YES;
 638                 break;
 639
 640         case ELFDATA2MSB:
 641                 /* We are little endian, DSO is big endian. */
 642                 if (*(unsigned char const *)&endian != 0)
 643                         dso->needs_swap = DSO_SWAP__YES;
 644                 break;
 645
 646         default:
 647                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 648                 return -EINVAL;
 649         }
 650
 651         return 0;
 652 }
 653
 654 bool symsrc__possibly_runtime(struct symsrc *ss)
 655 {
 656         return ss->dynsym || ss->opdsec;
 657 }
 658
 659 bool symsrc__has_symtab(struct symsrc *ss)
 660 {
 661         return ss->symtab != NULL;
 662 }
 663
 664 void symsrc__destroy(struct symsrc *ss)
 665 {
 666         zfree(&ss->name);
 667         elf_end(ss->elf);
 668         close(ss->fd);
 669 }
 670
 671 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 672 {
 673         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 674 }
 675
 676 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 677                  enum dso_binary_type type)
 678 {
 679         int err = -1;
 680         GElf_Ehdr ehdr;
 681         Elf *elf;
 682         int fd;
 683
 684         if (dso__needs_decompress(dso)) {
 685                 fd = dso__decompress_kmodule_fd(dso, name);
 686                 if (fd < 0)
 687                         return -1;
 688
 689                 type = dso->symtab_type;
 690         } else {
 691                 fd = open(name, O_RDONLY);
 692                 if (fd < 0) {
 693                         dso->load_errno = errno;
 694                         return -1;
 695                 }
 696         }
 697
 698         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 699         if (elf == NULL) {
 700                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 701                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 702                 goto out_close;
 703         }
 704
 705         if (gelf_getehdr(elf, &ehdr) == NULL) {
 706                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 707                 pr_debug("%s: cannot get elf header.\n", __func__);
 708                 goto out_elf_end;
 709         }
 710
 711         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 712                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 713                 goto out_elf_end;
 714         }
 715
 716         /* Always reject images with a mismatched build-id: */
 717         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 718                 u8 build_id[BUILD_ID_SIZE];
 719
 720                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 721                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 722                         goto out_elf_end;
 723                 }
 724
 725                 if (!dso__build_id_equal(dso, build_id)) {
 726                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 727                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 728                         goto out_elf_end;
 729                 }
 730         }
 731
 732         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 733
 734         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 735                         NULL);
 736         if (ss->symshdr.sh_type != SHT_SYMTAB)
 737                 ss->symtab = NULL;
 738
 739         ss->dynsym_idx = 0;
 740         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 741                         &ss->dynsym_idx);
 742         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 743                 ss->dynsym = NULL;
 744
 745         ss->opdidx = 0;
 746         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 747                         &ss->opdidx);
 748         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 749                 ss->opdsec = NULL;
 750
 751         if (dso->kernel == DSO_TYPE_USER)
 752                 ss->adjust_symbols = true;
 753         else
 754                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 755
 756         ss->name   = strdup(name);
 757         if (!ss->name) {
 758                 dso->load_errno = errno;
 759                 goto out_elf_end;
 760         }
 761
 762         ss->elf    = elf;
 763         ss->fd     = fd;
 764         ss->ehdr   = ehdr;
 765         ss->type   = type;
 766
 767         return 0;
 768
 769 out_elf_end:
 770         elf_end(elf);
 771 out_close:
 772         close(fd);
 773         return err;
 774 }
 775
 776 /**
 777  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 778  * @kmap: kernel maps and relocation reference symbol
 779  *
 780  * This function returns %true if we are dealing with the kernel maps and the
 781  * relocation reference symbol has not yet been found.  Otherwise %false is
 782  * returned.
 783  */
 784 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 785 {
 786         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 787                !kmap->ref_reloc_sym->unrelocated_addr;
 788 }
 789
 790 /**
 791  * ref_reloc - kernel relocation offset.
 792  * @kmap: kernel maps and relocation reference symbol
 793  *
 794  * This function returns the offset of kernel addresses as determined by using
 795  * the relocation reference symbol i.e. if the kernel has not been relocated
 796  * then the return value is zero.
 797  */
 798 static u64 ref_reloc(struct kmap *kmap)
 799 {
 800         if (kmap && kmap->ref_reloc_sym &&
 801             kmap->ref_reloc_sym->unrelocated_addr)
 802                 return kmap->ref_reloc_sym->addr -
 803                        kmap->ref_reloc_sym->unrelocated_addr;
 804         return 0;
 805 }
 806
 807 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 808                 GElf_Sym *sym __maybe_unused) { }
 809
 810 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 811                                       GElf_Sym *sym, GElf_Shdr *shdr,
 812                                       struct map_groups *kmaps, struct kmap *kmap,
 813                                       struct dso **curr_dsop, struct map **curr_mapp,
 814                                       const char *section_name,
 815                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 816 {
 817         struct dso *curr_dso = *curr_dsop;
 818         struct map *curr_map;
 819         char dso_name[PATH_MAX];
 820
 821         /* Adjust symbol to map to file offset */
 822         if (adjust_kernel_syms)
 823                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 824
 825         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 826                 return 0;
 827
 828         if (strcmp(section_name, ".text") == 0) {
 829                 /*
 830                  * The initial kernel mapping is based on
 831                  * kallsyms and identity maps.  Overwrite it to
 832                  * map to the kernel dso.
 833                  */
 834                 if (*remap_kernel && dso->kernel) {
 835                         *remap_kernel = false;
 836                         map->start = shdr->sh_addr + ref_reloc(kmap);
 837                         map->end = map->start + shdr->sh_size;
 838                         map->pgoff = shdr->sh_offset;
 839                         map->map_ip = map__map_ip;
 840                         map->unmap_ip = map__unmap_ip;
 841                         /* Ensure maps are correctly ordered */
 842                         if (kmaps) {
 843                                 map__get(map);
 844                                 map_groups__remove(kmaps, map);
 845                                 map_groups__insert(kmaps, map);
 846                                 map__put(map);
 847                         }
 848                 }
 849
 850                 /*
 851                  * The initial module mapping is based on
 852                  * /proc/modules mapped to offset zero.
 853                  * Overwrite it to map to the module dso.
 854                  */
 855                 if (*remap_kernel && kmodule) {
 856                         *remap_kernel = false;
 857                         map->pgoff = shdr->sh_offset;
 858                 }
 859
 860                 *curr_mapp = map;
 861                 *curr_dsop = dso;
 862                 return 0;
 863         }
 864
 865         if (!kmap)
 866                 return 0;
 867
 868         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 869
 870         curr_map = map_groups__find_by_name(kmaps, dso_name);
 871         if (curr_map == NULL) {
 872                 u64 start = sym->st_value;
 873
 874                 if (kmodule)
 875                         start += map->start + shdr->sh_offset;
 876
 877                 curr_dso = dso__new(dso_name);
 878                 if (curr_dso == NULL)
 879                         return -1;
 880                 curr_dso->kernel = dso->kernel;
 881                 curr_dso->long_name = dso->long_name;
 882                 curr_dso->long_name_len = dso->long_name_len;
 883                 curr_map = map__new2(start, curr_dso);
 884                 dso__put(curr_dso);
 885                 if (curr_map == NULL)
 886                         return -1;
 887
 888                 if (adjust_kernel_syms) {
 889                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 890                         curr_map->end    = curr_map->start + shdr->sh_size;
 891                         curr_map->pgoff  = shdr->sh_offset;
 892                 } else {
 893                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 894                 }
 895                 curr_dso->symtab_type = dso->symtab_type;
 896                 map_groups__insert(kmaps, curr_map);
 897                 /*
 898                  * Add it before we drop the referece to curr_map, i.e. while
 899                  * we still are sure to have a reference to this DSO via
 900                  * *curr_map->dso.
 901                  */
 902                 dsos__add(&map->groups->machine->dsos, curr_dso);
 903                 /* kmaps already got it */
 904                 map__put(curr_map);
 905                 dso__set_loaded(curr_dso);
 906                 *curr_mapp = curr_map;
 907                 *curr_dsop = curr_dso;
 908         } else
 909                 *curr_dsop = curr_map->dso;
 910
 911         return 0;
 912 }
 913
 914 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 915                   struct symsrc *runtime_ss, int kmodule)
 916 {
 917         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 918         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 919         struct map *curr_map = map;
 920         struct dso *curr_dso = dso;
 921         Elf_Data *symstrs, *secstrs;
 922         uint32_t nr_syms;
 923         int err = -1;
 924         uint32_t idx;
 925         GElf_Ehdr ehdr;
 926         GElf_Shdr shdr;
 927         GElf_Shdr tshdr;
 928         Elf_Data *syms, *opddata = NULL;
 929         GElf_Sym sym;
 930         Elf_Scn *sec, *sec_strndx;
 931         Elf *elf;
 932         int nr = 0;
 933         bool remap_kernel = false, adjust_kernel_syms = false;
 934
 935         if (kmap && !kmaps)
 936                 return -1;
 937
 938         dso->symtab_type = syms_ss->type;
 939         dso->is_64_bit = syms_ss->is_64_bit;
 940         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 941
 942         /*
 943          * Modules may already have symbols from kallsyms, but those symbols
 944          * have the wrong values for the dso maps, so remove them.
 945          */
 946         if (kmodule && syms_ss->symtab)
 947                 symbols__delete(&dso->symbols);
 948
 949         if (!syms_ss->symtab) {
 950                 /*
 951                  * If the vmlinux is stripped, fail so we will fall back
 952                  * to using kallsyms. The vmlinux runtime symbols aren't
 953                  * of much use.
 954                  */
 955                 if (dso->kernel)
 956                         goto out_elf_end;
 957
 958                 syms_ss->symtab  = syms_ss->dynsym;
 959                 syms_ss->symshdr = syms_ss->dynshdr;
 960         }
 961
 962         elf = syms_ss->elf;
 963         ehdr = syms_ss->ehdr;
 964         sec = syms_ss->symtab;
 965         shdr = syms_ss->symshdr;
 966
 967         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
 968                                 ".text", NULL))
 969                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
 970
 971         if (runtime_ss->opdsec)
 972                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 973
 974         syms = elf_getdata(sec, NULL);
 975         if (syms == NULL)
 976                 goto out_elf_end;
 977
 978         sec = elf_getscn(elf, shdr.sh_link);
 979         if (sec == NULL)
 980                 goto out_elf_end;
 981
 982         symstrs = elf_getdata(sec, NULL);
 983         if (symstrs == NULL)
 984                 goto out_elf_end;
 985
 986         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 987         if (sec_strndx == NULL)
 988                 goto out_elf_end;
 989
 990         secstrs = elf_getdata(sec_strndx, NULL);
 991         if (secstrs == NULL)
 992                 goto out_elf_end;
 993
 994         nr_syms = shdr.sh_size / shdr.sh_entsize;
 995
 996         memset(&sym, 0, sizeof(sym));
 997
 998         /*
 999          * The kernel relocation symbol is needed in advance in order to adjust
1000          * kernel maps correctly.
1001          */
1002         if (ref_reloc_sym_not_found(kmap)) {
1003                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1004                         const char *elf_name = elf_sym__name(&sym, symstrs);
1005
1006                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1007                                 continue;
1008                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1009                         map->reloc = kmap->ref_reloc_sym->addr -
1010                                      kmap->ref_reloc_sym->unrelocated_addr;
1011                         break;
1012                 }
1013         }
1014
1015         /*
1016          * Handle any relocation of vdso necessary because older kernels
1017          * attempted to prelink vdso to its virtual address.
1018          */
1019         if (dso__is_vdso(dso))
1020                 map->reloc = map->start - dso->text_offset;
1021
1022         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1023         /*
1024          * Initial kernel and module mappings do not map to the dso.
1025          * Flag the fixups.
1026          */
1027         if (dso->kernel || kmodule) {
1028                 remap_kernel = true;
1029                 adjust_kernel_syms = dso->adjust_symbols;
1030         }
1031         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1032                 struct symbol *f;
1033                 const char *elf_name = elf_sym__name(&sym, symstrs);
1034                 char *demangled = NULL;
1035                 int is_label = elf_sym__is_label(&sym);
1036                 const char *section_name;
1037                 bool used_opd = false;
1038
1039                 if (!is_label && !elf_sym__filter(&sym))
1040                         continue;
1041
1042                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1043                  * don't identify functions, so will confuse the profile
1044                  * output: */
1045                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1046                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1047                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1048                                 continue;
1049                 }
1050
1051                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1052                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1053                         u64 *opd = opddata->d_buf + offset;
1054                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1055                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1056                                         sym.st_value);
1057                         used_opd = true;
1058                 }
1059                 /*
1060                  * When loading symbols in a data mapping, ABS symbols (which
1061                  * has a value of SHN_ABS in its st_shndx) failed at
1062                  * elf_getscn().  And it marks the loading as a failure so
1063                  * already loaded symbols cannot be fixed up.
1064                  *
1065                  * I'm not sure what should be done. Just ignore them for now.
1066                  * - Namhyung Kim
1067                  */
1068                 if (sym.st_shndx == SHN_ABS)
1069                         continue;
1070
1071                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1072                 if (!sec)
1073                         goto out_elf_end;
1074
1075                 gelf_getshdr(sec, &shdr);
1076
1077                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1078                         continue;
1079
1080                 section_name = elf_sec__name(&shdr, secstrs);
1081
1082                 /* On ARM, symbols for thumb functions have 1 added to
1083                  * the symbol address as a flag - remove it */
1084                 if ((ehdr.e_machine == EM_ARM) &&
1085                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1086                     (sym.st_value & 1))
1087                         --sym.st_value;
1088
1089                 if (dso->kernel || kmodule) {
1090                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1091                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1092                                 goto out_elf_end;
1093                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1094                            (!used_opd && syms_ss->adjust_symbols)) {
1095                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1096                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1097                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1098                                   (u64)shdr.sh_offset);
1099                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1100                 }
1101
1102                 demangled = demangle_sym(dso, kmodule, elf_name);
1103                 if (demangled != NULL)
1104                         elf_name = demangled;
1105
1106                 f = symbol__new(sym.st_value, sym.st_size,
1107                                 GELF_ST_BIND(sym.st_info),
1108                                 GELF_ST_TYPE(sym.st_info), elf_name);
1109                 free(demangled);
1110                 if (!f)
1111                         goto out_elf_end;
1112
1113                 arch__sym_update(f, &sym);
1114
1115                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1116                 nr++;
1117         }
1118
1119         /*
1120          * For misannotated, zeroed, ASM function sizes.
1121          */
1122         if (nr > 0) {
1123                 symbols__fixup_end(&dso->symbols);
1124                 symbols__fixup_duplicate(&dso->symbols);
1125                 if (kmap) {
1126                         /*
1127                          * We need to fixup this here too because we create new
1128                          * maps here, for things like vsyscall sections.
1129                          */
1130                         map_groups__fixup_end(kmaps);
1131                 }
1132         }
1133         err = nr;
1134 out_elf_end:
1135         return err;
1136 }
1137
1138 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1139 {
1140         GElf_Phdr phdr;
1141         size_t i, phdrnum;
1142         int err;
1143         u64 sz;
1144
1145         if (elf_getphdrnum(elf, &phdrnum))
1146                 return -1;
1147
1148         for (i = 0; i < phdrnum; i++) {
1149                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1150                         return -1;
1151                 if (phdr.p_type != PT_LOAD)
1152                         continue;
1153                 if (exe) {
1154                         if (!(phdr.p_flags & PF_X))
1155                                 continue;
1156                 } else {
1157                         if (!(phdr.p_flags & PF_R))
1158                                 continue;
1159                 }
1160                 sz = min(phdr.p_memsz, phdr.p_filesz);
1161                 if (!sz)
1162                         continue;
1163                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1164                 if (err)
1165                         return err;
1166         }
1167         return 0;
1168 }
1169
1170 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1171                     bool *is_64_bit)
1172 {
1173         int err;
1174         Elf *elf;
1175
1176         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1177         if (elf == NULL)
1178                 return -1;
1179
1180         if (is_64_bit)
1181                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1182
1183         err = elf_read_maps(elf, exe, mapfn, data);
1184
1185         elf_end(elf);
1186         return err;
1187 }
1188
1189 enum dso_type dso__type_fd(int fd)
1190 {
1191         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1192         GElf_Ehdr ehdr;
1193         Elf_Kind ek;
1194         Elf *elf;
1195
1196         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1197         if (elf == NULL)
1198                 goto out;
1199
1200         ek = elf_kind(elf);
1201         if (ek != ELF_K_ELF)
1202                 goto out_end;
1203
1204         if (gelf_getclass(elf) == ELFCLASS64) {
1205                 dso_type = DSO__TYPE_64BIT;
1206                 goto out_end;
1207         }
1208
1209         if (gelf_getehdr(elf, &ehdr) == NULL)
1210                 goto out_end;
1211
1212         if (ehdr.e_machine == EM_X86_64)
1213                 dso_type = DSO__TYPE_X32BIT;
1214         else
1215                 dso_type = DSO__TYPE_32BIT;
1216 out_end:
1217         elf_end(elf);
1218 out:
1219         return dso_type;
1220 }
1221
1222 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1223 {
1224         ssize_t r;
1225         size_t n;
1226         int err = -1;
1227         char *buf = malloc(page_size);
1228
1229         if (buf == NULL)
1230                 return -1;
1231
1232         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1233                 goto out;
1234
1235         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1236                 goto out;
1237
1238         while (len) {
1239                 n = page_size;
1240                 if (len < n)
1241                         n = len;
1242                 /* Use read because mmap won't work on proc files */
1243                 r = read(from, buf, n);
1244                 if (r < 0)
1245                         goto out;
1246                 if (!r)
1247                         break;
1248                 n = r;
1249                 r = write(to, buf, n);
1250                 if (r < 0)
1251                         goto out;
1252                 if ((size_t)r != n)
1253                         goto out;
1254                 len -= n;
1255         }
1256
1257         err = 0;
1258 out:
1259         free(buf);
1260         return err;
1261 }
1262
1263 struct kcore {
1264         int fd;
1265         int elfclass;
1266         Elf *elf;
1267         GElf_Ehdr ehdr;
1268 };
1269
1270 static int kcore__open(struct kcore *kcore, const char *filename)
1271 {
1272         GElf_Ehdr *ehdr;
1273
1274         kcore->fd = open(filename, O_RDONLY);
1275         if (kcore->fd == -1)
1276                 return -1;
1277
1278         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1279         if (!kcore->elf)
1280                 goto out_close;
1281
1282         kcore->elfclass = gelf_getclass(kcore->elf);
1283         if (kcore->elfclass == ELFCLASSNONE)
1284                 goto out_end;
1285
1286         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1287         if (!ehdr)
1288                 goto out_end;
1289
1290         return 0;
1291
1292 out_end:
1293         elf_end(kcore->elf);
1294 out_close:
1295         close(kcore->fd);
1296         return -1;
1297 }
1298
1299 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1300                        bool temp)
1301 {
1302         kcore->elfclass = elfclass;
1303
1304         if (temp)
1305                 kcore->fd = mkstemp(filename);
1306         else
1307                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1308         if (kcore->fd == -1)
1309                 return -1;
1310
1311         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1312         if (!kcore->elf)
1313                 goto out_close;
1314
1315         if (!gelf_newehdr(kcore->elf, elfclass))
1316                 goto out_end;
1317
1318         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1319
1320         return 0;
1321
1322 out_end:
1323         elf_end(kcore->elf);
1324 out_close:
1325         close(kcore->fd);
1326         unlink(filename);
1327         return -1;
1328 }
1329
1330 static void kcore__close(struct kcore *kcore)
1331 {
1332         elf_end(kcore->elf);
1333         close(kcore->fd);
1334 }
1335
1336 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1337 {
1338         GElf_Ehdr *ehdr = &to->ehdr;
1339         GElf_Ehdr *kehdr = &from->ehdr;
1340
1341         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1342         ehdr->e_type      = kehdr->e_type;
1343         ehdr->e_machine   = kehdr->e_machine;
1344         ehdr->e_version   = kehdr->e_version;
1345         ehdr->e_entry     = 0;
1346         ehdr->e_shoff     = 0;
1347         ehdr->e_flags     = kehdr->e_flags;
1348         ehdr->e_phnum     = count;
1349         ehdr->e_shentsize = 0;
1350         ehdr->e_shnum     = 0;
1351         ehdr->e_shstrndx  = 0;
1352
1353         if (from->elfclass == ELFCLASS32) {
1354                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1355                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1356                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1357         } else {
1358                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1359                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1360                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1361         }
1362
1363         if (!gelf_update_ehdr(to->elf, ehdr))
1364                 return -1;
1365
1366         if (!gelf_newphdr(to->elf, count))
1367                 return -1;
1368
1369         return 0;
1370 }
1371
1372 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1373                            u64 addr, u64 len)
1374 {
1375         GElf_Phdr phdr = {
1376                 .p_type         = PT_LOAD,
1377                 .p_flags        = PF_R | PF_W | PF_X,
1378                 .p_offset       = offset,
1379                 .p_vaddr        = addr,
1380                 .p_paddr        = 0,
1381                 .p_filesz       = len,
1382                 .p_memsz        = len,
1383                 .p_align        = page_size,
1384         };
1385
1386         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1387                 return -1;
1388
1389         return 0;
1390 }
1391
1392 static off_t kcore__write(struct kcore *kcore)
1393 {
1394         return elf_update(kcore->elf, ELF_C_WRITE);
1395 }
1396
1397 struct phdr_data {
1398         off_t offset;
1399         off_t rel;
1400         u64 addr;
1401         u64 len;
1402         struct list_head node;
1403         struct phdr_data *remaps;
1404 };
1405
1406 struct sym_data {
1407         u64 addr;
1408         struct list_head node;
1409 };
1410
1411 struct kcore_copy_info {
1412         u64 stext;
1413         u64 etext;
1414         u64 first_symbol;
1415         u64 last_symbol;
1416         u64 first_module;
1417         u64 last_module_symbol;
1418         size_t phnum;
1419         struct list_head phdrs;
1420         struct list_head syms;
1421 };
1422
1423 #define kcore_copy__for_each_phdr(k, p) \
1424         list_for_each_entry((p), &(k)->phdrs, node)
1425
1426 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1427 {
1428         struct phdr_data *p = zalloc(sizeof(*p));
1429
1430         if (p) {
1431                 p->addr   = addr;
1432                 p->len    = len;
1433                 p->offset = offset;
1434         }
1435
1436         return p;
1437 }
1438
1439 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1440                                                  u64 addr, u64 len,
1441                                                  off_t offset)
1442 {
1443         struct phdr_data *p = phdr_data__new(addr, len, offset);
1444
1445         if (p)
1446                 list_add_tail(&p->node, &kci->phdrs);
1447
1448         return p;
1449 }
1450
1451 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1452 {
1453         struct phdr_data *p, *tmp;
1454
1455         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1456                 list_del(&p->node);
1457                 free(p);
1458         }
1459 }
1460
1461 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1462                                             u64 addr)
1463 {
1464         struct sym_data *s = zalloc(sizeof(*s));
1465
1466         if (s) {
1467                 s->addr = addr;
1468                 list_add_tail(&s->node, &kci->syms);
1469         }
1470
1471         return s;
1472 }
1473
1474 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1475 {
1476         struct sym_data *s, *tmp;
1477
1478         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1479                 list_del(&s->node);
1480                 free(s);
1481         }
1482 }
1483
1484 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1485                                         u64 start)
1486 {
1487         struct kcore_copy_info *kci = arg;
1488
1489         if (!kallsyms__is_function(type))
1490                 return 0;
1491
1492         if (strchr(name, '[')) {
1493                 if (start > kci->last_module_symbol)
1494                         kci->last_module_symbol = start;
1495                 return 0;
1496         }
1497
1498         if (!kci->first_symbol || start < kci->first_symbol)
1499                 kci->first_symbol = start;
1500
1501         if (!kci->last_symbol || start > kci->last_symbol)
1502                 kci->last_symbol = start;
1503
1504         if (!strcmp(name, "_stext")) {
1505                 kci->stext = start;
1506                 return 0;
1507         }
1508
1509         if (!strcmp(name, "_etext")) {
1510                 kci->etext = start;
1511                 return 0;
1512         }
1513
1514         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1515                 return -1;
1516
1517         return 0;
1518 }
1519
1520 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1521                                       const char *dir)
1522 {
1523         char kallsyms_filename[PATH_MAX];
1524
1525         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1526
1527         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1528                 return -1;
1529
1530         if (kallsyms__parse(kallsyms_filename, kci,
1531                             kcore_copy__process_kallsyms) < 0)
1532                 return -1;
1533
1534         return 0;
1535 }
1536
1537 static int kcore_copy__process_modules(void *arg,
1538                                        const char *name __maybe_unused,
1539                                        u64 start, u64 size __maybe_unused)
1540 {
1541         struct kcore_copy_info *kci = arg;
1542
1543         if (!kci->first_module || start < kci->first_module)
1544                 kci->first_module = start;
1545
1546         return 0;
1547 }
1548
1549 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1550                                      const char *dir)
1551 {
1552         char modules_filename[PATH_MAX];
1553
1554         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1555
1556         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1557                 return -1;
1558
1559         if (modules__parse(modules_filename, kci,
1560                            kcore_copy__process_modules) < 0)
1561                 return -1;
1562
1563         return 0;
1564 }
1565
1566 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1567                            u64 pgoff, u64 s, u64 e)
1568 {
1569         u64 len, offset;
1570
1571         if (s < start || s >= end)
1572                 return 0;
1573
1574         offset = (s - start) + pgoff;
1575         len = e < end ? e - s : end - s;
1576
1577         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1578 }
1579
1580 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1581 {
1582         struct kcore_copy_info *kci = data;
1583         u64 end = start + len;
1584         struct sym_data *sdat;
1585
1586         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1587                 return -1;
1588
1589         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1590                             kci->last_module_symbol))
1591                 return -1;
1592
1593         list_for_each_entry(sdat, &kci->syms, node) {
1594                 u64 s = round_down(sdat->addr, page_size);
1595
1596                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1597                         return -1;
1598         }
1599
1600         return 0;
1601 }
1602
1603 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1604 {
1605         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1606                 return -1;
1607
1608         return 0;
1609 }
1610
1611 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1612 {
1613         struct phdr_data *p, *k = NULL;
1614         u64 kend;
1615
1616         if (!kci->stext)
1617                 return;
1618
1619         /* Find phdr that corresponds to the kernel map (contains stext) */
1620         kcore_copy__for_each_phdr(kci, p) {
1621                 u64 pend = p->addr + p->len - 1;
1622
1623                 if (p->addr <= kci->stext && pend >= kci->stext) {
1624                         k = p;
1625                         break;
1626                 }
1627         }
1628
1629         if (!k)
1630                 return;
1631
1632         kend = k->offset + k->len;
1633
1634         /* Find phdrs that remap the kernel */
1635         kcore_copy__for_each_phdr(kci, p) {
1636                 u64 pend = p->offset + p->len;
1637
1638                 if (p == k)
1639                         continue;
1640
1641                 if (p->offset >= k->offset && pend <= kend)
1642                         p->remaps = k;
1643         }
1644 }
1645
1646 static void kcore_copy__layout(struct kcore_copy_info *kci)
1647 {
1648         struct phdr_data *p;
1649         off_t rel = 0;
1650
1651         kcore_copy__find_remaps(kci);
1652
1653         kcore_copy__for_each_phdr(kci, p) {
1654                 if (!p->remaps) {
1655                         p->rel = rel;
1656                         rel += p->len;
1657                 }
1658                 kci->phnum += 1;
1659         }
1660
1661         kcore_copy__for_each_phdr(kci, p) {
1662                 struct phdr_data *k = p->remaps;
1663
1664                 if (k)
1665                         p->rel = p->offset - k->offset + k->rel;
1666         }
1667 }
1668
1669 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1670                                  Elf *elf)
1671 {
1672         if (kcore_copy__parse_kallsyms(kci, dir))
1673                 return -1;
1674
1675         if (kcore_copy__parse_modules(kci, dir))
1676                 return -1;
1677
1678         if (kci->stext)
1679                 kci->stext = round_down(kci->stext, page_size);
1680         else
1681                 kci->stext = round_down(kci->first_symbol, page_size);
1682
1683         if (kci->etext) {
1684                 kci->etext = round_up(kci->etext, page_size);
1685         } else if (kci->last_symbol) {
1686                 kci->etext = round_up(kci->last_symbol, page_size);
1687                 kci->etext += page_size;
1688         }
1689
1690         kci->first_module = round_down(kci->first_module, page_size);
1691
1692         if (kci->last_module_symbol) {
1693                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1694                                                    page_size);
1695                 kci->last_module_symbol += page_size;
1696         }
1697
1698         if (!kci->stext || !kci->etext)
1699                 return -1;
1700
1701         if (kci->first_module && !kci->last_module_symbol)
1702                 return -1;
1703
1704         if (kcore_copy__read_maps(kci, elf))
1705                 return -1;
1706
1707         kcore_copy__layout(kci);
1708
1709         return 0;
1710 }
1711
1712 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1713                                  const char *name)
1714 {
1715         char from_filename[PATH_MAX];
1716         char to_filename[PATH_MAX];
1717
1718         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1719         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1720
1721         return copyfile_mode(from_filename, to_filename, 0400);
1722 }
1723
1724 static int kcore_copy__unlink(const char *dir, const char *name)
1725 {
1726         char filename[PATH_MAX];
1727
1728         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1729
1730         return unlink(filename);
1731 }
1732
1733 static int kcore_copy__compare_fds(int from, int to)
1734 {
1735         char *buf_from;
1736         char *buf_to;
1737         ssize_t ret;
1738         size_t len;
1739         int err = -1;
1740
1741         buf_from = malloc(page_size);
1742         buf_to = malloc(page_size);
1743         if (!buf_from || !buf_to)
1744                 goto out;
1745
1746         while (1) {
1747                 /* Use read because mmap won't work on proc files */
1748                 ret = read(from, buf_from, page_size);
1749                 if (ret < 0)
1750                         goto out;
1751
1752                 if (!ret)
1753                         break;
1754
1755                 len = ret;
1756
1757                 if (readn(to, buf_to, len) != (int)len)
1758                         goto out;
1759
1760                 if (memcmp(buf_from, buf_to, len))
1761                         goto out;
1762         }
1763
1764         err = 0;
1765 out:
1766         free(buf_to);
1767         free(buf_from);
1768         return err;
1769 }
1770
1771 static int kcore_copy__compare_files(const char *from_filename,
1772                                      const char *to_filename)
1773 {
1774         int from, to, err = -1;
1775
1776         from = open(from_filename, O_RDONLY);
1777         if (from < 0)
1778                 return -1;
1779
1780         to = open(to_filename, O_RDONLY);
1781         if (to < 0)
1782                 goto out_close_from;
1783
1784         err = kcore_copy__compare_fds(from, to);
1785
1786         close(to);
1787 out_close_from:
1788         close(from);
1789         return err;
1790 }
1791
1792 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1793                                     const char *name)
1794 {
1795         char from_filename[PATH_MAX];
1796         char to_filename[PATH_MAX];
1797
1798         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1799         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1800
1801         return kcore_copy__compare_files(from_filename, to_filename);
1802 }
1803
1804 /**
1805  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1806  * @from_dir: from directory
1807  * @to_dir: to directory
1808  *
1809  * This function copies kallsyms, modules and kcore files from one directory to
1810  * another.  kallsyms and modules are copied entirely.  Only code segments are
1811  * copied from kcore.  It is assumed that two segments suffice: one for the
1812  * kernel proper and one for all the modules.  The code segments are determined
1813  * from kallsyms and modules files.  The kernel map starts at _stext or the
1814  * lowest function symbol, and ends at _etext or the highest function symbol.
1815  * The module map starts at the lowest module address and ends at the highest
1816  * module symbol.  Start addresses are rounded down to the nearest page.  End
1817  * addresses are rounded up to the nearest page.  An extra page is added to the
1818  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1819  * symbol too.  Because it contains only code sections, the resulting kcore is
1820  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1821  * is not the same for the kernel map and the modules map.  That happens because
1822  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1823  * kallsyms and modules files are compared with their copies to check that
1824  * modules have not been loaded or unloaded while the copies were taking place.
1825  *
1826  * Return: %0 on success, %-1 on failure.
1827  */
1828 int kcore_copy(const char *from_dir, const char *to_dir)
1829 {
1830         struct kcore kcore;
1831         struct kcore extract;
1832         int idx = 0, err = -1;
1833         off_t offset, sz;
1834         struct kcore_copy_info kci = { .stext = 0, };
1835         char kcore_filename[PATH_MAX];
1836         char extract_filename[PATH_MAX];
1837         struct phdr_data *p;
1838
1839         INIT_LIST_HEAD(&kci.phdrs);
1840         INIT_LIST_HEAD(&kci.syms);
1841
1842         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1843                 return -1;
1844
1845         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1846                 goto out_unlink_kallsyms;
1847
1848         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1849         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1850
1851         if (kcore__open(&kcore, kcore_filename))
1852                 goto out_unlink_modules;
1853
1854         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1855                 goto out_kcore_close;
1856
1857         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1858                 goto out_kcore_close;
1859
1860         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1861                 goto out_extract_close;
1862
1863         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1864                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1865         offset = round_up(offset, page_size);
1866
1867         kcore_copy__for_each_phdr(&kci, p) {
1868                 off_t offs = p->rel + offset;
1869
1870                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1871                         goto out_extract_close;
1872         }
1873
1874         sz = kcore__write(&extract);
1875         if (sz < 0 || sz > offset)
1876                 goto out_extract_close;
1877
1878         kcore_copy__for_each_phdr(&kci, p) {
1879                 off_t offs = p->rel + offset;
1880
1881                 if (p->remaps)
1882                         continue;
1883                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1884                         goto out_extract_close;
1885         }
1886
1887         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1888                 goto out_extract_close;
1889
1890         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1891                 goto out_extract_close;
1892
1893         err = 0;
1894
1895 out_extract_close:
1896         kcore__close(&extract);
1897         if (err)
1898                 unlink(extract_filename);
1899 out_kcore_close:
1900         kcore__close(&kcore);
1901 out_unlink_modules:
1902         if (err)
1903                 kcore_copy__unlink(to_dir, "modules");
1904 out_unlink_kallsyms:
1905         if (err)
1906                 kcore_copy__unlink(to_dir, "kallsyms");
1907
1908         kcore_copy__free_phdrs(&kci);
1909         kcore_copy__free_syms(&kci);
1910
1911         return err;
1912 }
1913
1914 int kcore_extract__create(struct kcore_extract *kce)
1915 {
1916         struct kcore kcore;
1917         struct kcore extract;
1918         size_t count = 1;
1919         int idx = 0, err = -1;
1920         off_t offset = page_size, sz;
1921
1922         if (kcore__open(&kcore, kce->kcore_filename))
1923                 return -1;
1924
1925         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1926         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1927                 goto out_kcore_close;
1928
1929         if (kcore__copy_hdr(&kcore, &extract, count))
1930                 goto out_extract_close;
1931
1932         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1933                 goto out_extract_close;
1934
1935         sz = kcore__write(&extract);
1936         if (sz < 0 || sz > offset)
1937                 goto out_extract_close;
1938
1939         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1940                 goto out_extract_close;
1941
1942         err = 0;
1943
1944 out_extract_close:
1945         kcore__close(&extract);
1946         if (err)
1947                 unlink(kce->extract_filename);
1948 out_kcore_close:
1949         kcore__close(&kcore);
1950
1951         return err;
1952 }
1953
1954 void kcore_extract__delete(struct kcore_extract *kce)
1955 {
1956         unlink(kce->extract_filename);
1957 }
1958
1959 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1960 /**
1961  * populate_sdt_note : Parse raw data and identify SDT note
1962  * @elf: elf of the opened file
1963  * @data: raw data of a section with description offset applied
1964  * @len: note description size
1965  * @type: type of the note
1966  * @sdt_notes: List to add the SDT note
1967  *
1968  * Responsible for parsing the @data in section .note.stapsdt in @elf and
1969  * if its an SDT note, it appends to @sdt_notes list.
1970  */
1971 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1972                              struct list_head *sdt_notes)
1973 {
1974         const char *provider, *name, *args;
1975         struct sdt_note *tmp = NULL;
1976         GElf_Ehdr ehdr;
1977         GElf_Addr base_off = 0;
1978         GElf_Shdr shdr;
1979         int ret = -EINVAL;
1980
1981         union {
1982                 Elf64_Addr a64[NR_ADDR];
1983                 Elf32_Addr a32[NR_ADDR];
1984         } buf;
1985
1986         Elf_Data dst = {
1987                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1988                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1989                 .d_off = 0, .d_align = 0
1990         };
1991         Elf_Data src = {
1992                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1993                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1994                 .d_align = 0
1995         };
1996
1997         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1998         if (!tmp) {
1999                 ret = -ENOMEM;
2000                 goto out_err;
2001         }
2002
2003         INIT_LIST_HEAD(&tmp->note_list);
2004
2005         if (len < dst.d_size + 3)
2006                 goto out_free_note;
2007
2008         /* Translation from file representation to memory representation */
2009         if (gelf_xlatetom(*elf, &dst, &src,
2010                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2011                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2012                 goto out_free_note;
2013         }
2014
2015         /* Populate the fields of sdt_note */
2016         provider = data + dst.d_size;
2017
2018         name = (const char *)memchr(provider, '\0', data + len - provider);
2019         if (name++ == NULL)
2020                 goto out_free_note;
2021
2022         tmp->provider = strdup(provider);
2023         if (!tmp->provider) {
2024                 ret = -ENOMEM;
2025                 goto out_free_note;
2026         }
2027         tmp->name = strdup(name);
2028         if (!tmp->name) {
2029                 ret = -ENOMEM;
2030                 goto out_free_prov;
2031         }
2032
2033         args = memchr(name, '\0', data + len - name);
2034
2035         /*
2036          * There is no argument if:
2037          * - We reached the end of the note;
2038          * - There is not enough room to hold a potential string;
2039          * - The argument string is empty or just contains ':'.
2040          */
2041         if (args == NULL || data + len - args < 2 ||
2042                 args[1] == ':' || args[1] == '\0')
2043                 tmp->args = NULL;
2044         else {
2045                 tmp->args = strdup(++args);
2046                 if (!tmp->args) {
2047                         ret = -ENOMEM;
2048                         goto out_free_name;
2049                 }
2050         }
2051
2052         if (gelf_getclass(*elf) == ELFCLASS32) {
2053                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2054                 tmp->bit32 = true;
2055         } else {
2056                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2057                 tmp->bit32 = false;
2058         }
2059
2060         if (!gelf_getehdr(*elf, &ehdr)) {
2061                 pr_debug("%s : cannot get elf header.\n", __func__);
2062                 ret = -EBADF;
2063                 goto out_free_args;
2064         }
2065
2066         /* Adjust the prelink effect :
2067          * Find out the .stapsdt.base section.
2068          * This scn will help us to handle prelinking (if present).
2069          * Compare the retrieved file offset of the base section with the
2070          * base address in the description of the SDT note. If its different,
2071          * then accordingly, adjust the note location.
2072          */
2073         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
2074                 base_off = shdr.sh_offset;
2075                 if (base_off) {
2076                         if (tmp->bit32)
2077                                 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
2078                                         tmp->addr.a32[1];
2079                         else
2080                                 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
2081                                         tmp->addr.a64[1];
2082                 }
2083         }
2084
2085         list_add_tail(&tmp->note_list, sdt_notes);
2086         return 0;
2087
2088 out_free_args:
2089         free(tmp->args);
2090 out_free_name:
2091         free(tmp->name);
2092 out_free_prov:
2093         free(tmp->provider);
2094 out_free_note:
2095         free(tmp);
2096 out_err:
2097         return ret;
2098 }
2099
2100 /**
2101  * construct_sdt_notes_list : constructs a list of SDT notes
2102  * @elf : elf to look into
2103  * @sdt_notes : empty list_head
2104  *
2105  * Scans the sections in 'elf' for the section
2106  * .note.stapsdt. It, then calls populate_sdt_note to find
2107  * out the SDT events and populates the 'sdt_notes'.
2108  */
2109 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2110 {
2111         GElf_Ehdr ehdr;
2112         Elf_Scn *scn = NULL;
2113         Elf_Data *data;
2114         GElf_Shdr shdr;
2115         size_t shstrndx, next;
2116         GElf_Nhdr nhdr;
2117         size_t name_off, desc_off, offset;
2118         int ret = 0;
2119
2120         if (gelf_getehdr(elf, &ehdr) == NULL) {
2121                 ret = -EBADF;
2122                 goto out_ret;
2123         }
2124         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2125                 ret = -EBADF;
2126                 goto out_ret;
2127         }
2128
2129         /* Look for the required section */
2130         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2131         if (!scn) {
2132                 ret = -ENOENT;
2133                 goto out_ret;
2134         }
2135
2136         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2137                 ret = -ENOENT;
2138                 goto out_ret;
2139         }
2140
2141         data = elf_getdata(scn, NULL);
2142
2143         /* Get the SDT notes */
2144         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2145                                               &desc_off)) > 0; offset = next) {
2146                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2147                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2148                             sizeof(SDT_NOTE_NAME))) {
2149                         /* Check the type of the note */
2150                         if (nhdr.n_type != SDT_NOTE_TYPE)
2151                                 goto out_ret;
2152
2153                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2154                                                 nhdr.n_descsz, sdt_notes);
2155                         if (ret < 0)
2156                                 goto out_ret;
2157                 }
2158         }
2159         if (list_empty(sdt_notes))
2160                 ret = -ENOENT;
2161
2162 out_ret:
2163         return ret;
2164 }
2165
2166 /**
2167  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2168  * @head : empty list_head
2169  * @target : file to find SDT notes from
2170  *
2171  * This opens the file, initializes
2172  * the ELF and then calls construct_sdt_notes_list.
2173  */
2174 int get_sdt_note_list(struct list_head *head, const char *target)
2175 {
2176         Elf *elf;
2177         int fd, ret;
2178
2179         fd = open(target, O_RDONLY);
2180         if (fd < 0)
2181                 return -EBADF;
2182
2183         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2184         if (!elf) {
2185                 ret = -EBADF;
2186                 goto out_close;
2187         }
2188         ret = construct_sdt_notes_list(elf, head);
2189         elf_end(elf);
2190 out_close:
2191         close(fd);
2192         return ret;
2193 }
2194
2195 /**
2196  * cleanup_sdt_note_list : free the sdt notes' list
2197  * @sdt_notes: sdt notes' list
2198  *
2199  * Free up the SDT notes in @sdt_notes.
2200  * Returns the number of SDT notes free'd.
2201  */
2202 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2203 {
2204         struct sdt_note *tmp, *pos;
2205         int nr_free = 0;
2206
2207         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2208                 list_del(&pos->note_list);
2209                 free(pos->name);
2210                 free(pos->provider);
2211                 free(pos);
2212                 nr_free++;
2213         }
2214         return nr_free;
2215 }
2216
2217 /**
2218  * sdt_notes__get_count: Counts the number of sdt events
2219  * @start: list_head to sdt_notes list
2220  *
2221  * Returns the number of SDT notes in a list
2222  */
2223 int sdt_notes__get_count(struct list_head *start)
2224 {
2225         struct sdt_note *sdt_ptr;
2226         int count = 0;
2227
2228         list_for_each_entry(sdt_ptr, start, note_list)
2229                 count++;
2230         return count;
2231 }
2232 #endif
2233
2234 void symbol__elf_init(void)
2235 {
2236         elf_version(EV_CURRENT);
2237 }