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 <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <inttypes.h>
   9
  10 #include "map.h"
  11 #include "map_groups.h"
  12 #include "symbol.h"
  13 #include "symsrc.h"
  14 #include "demangle-java.h"
  15 #include "demangle-rust.h"
  16 #include "machine.h"
  17 #include "vdso.h"
  18 #include "debug.h"
  19 #include "util.h"
  20 #include <linux/ctype.h>
  21 #include <linux/zalloc.h>
  22 #include <symbol/kallsyms.h>
  23
  24 #ifndef EM_AARCH64
  25 #define EM_AARCH64      183  /* ARM 64 bit */
  26 #endif
  27
  28 #ifndef ELF32_ST_VISIBILITY
  29 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  30 #endif
  31
  32 /* For ELF64 the definitions are the same.  */
  33 #ifndef ELF64_ST_VISIBILITY
  34 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  35 #endif
  36
  37 /* How to extract information held in the st_other field.  */
  38 #ifndef GELF_ST_VISIBILITY
  39 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  40 #endif
  41
  42 typedef Elf64_Nhdr GElf_Nhdr;
  43
  44 #ifndef DMGL_PARAMS
  45 #define DMGL_NO_OPTS     0              /* For readability... */
  46 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  47 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  48 #endif
  49
  50 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  51 extern char *cplus_demangle(const char *, int);
  52
  53 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  54 {
  55         return cplus_demangle(c, i);
  56 }
  57 #else
  58 #ifdef NO_DEMANGLE
  59 static inline char *bfd_demangle(void __maybe_unused *v,
  60                                  const char __maybe_unused *c,
  61                                  int __maybe_unused i)
  62 {
  63         return NULL;
  64 }
  65 #else
  66 #define PACKAGE 'perf'
  67 #include <bfd.h>
  68 #endif
  69 #endif
  70
  71 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  72 static int elf_getphdrnum(Elf *elf, size_t *dst)
  73 {
  74         GElf_Ehdr gehdr;
  75         GElf_Ehdr *ehdr;
  76
  77         ehdr = gelf_getehdr(elf, &gehdr);
  78         if (!ehdr)
  79                 return -1;
  80
  81         *dst = ehdr->e_phnum;
  82
  83         return 0;
  84 }
  85 #endif
  86
  87 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  88 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  89 {
  90         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  91         return -1;
  92 }
  93 #endif
  94
  95 #ifndef NT_GNU_BUILD_ID
  96 #define NT_GNU_BUILD_ID 3
  97 #endif
  98
  99 /**
 100  * elf_symtab__for_each_symbol - iterate thru all the symbols
 101  *
 102  * @syms: struct elf_symtab instance to iterate
 103  * @idx: uint32_t idx
 104  * @sym: GElf_Sym iterator
 105  */
 106 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 107         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 108              idx < nr_syms; \
 109              idx++, gelf_getsym(syms, idx, &sym))
 110
 111 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 112 {
 113         return GELF_ST_TYPE(sym->st_info);
 114 }
 115
 116 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 117 {
 118         return GELF_ST_VISIBILITY(sym->st_other);
 119 }
 120
 121 #ifndef STT_GNU_IFUNC
 122 #define STT_GNU_IFUNC 10
 123 #endif
 124
 125 static inline int elf_sym__is_function(const GElf_Sym *sym)
 126 {
 127         return (elf_sym__type(sym) == STT_FUNC ||
 128                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 129                sym->st_name != 0 &&
 130                sym->st_shndx != SHN_UNDEF;
 131 }
 132
 133 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 134 {
 135         return elf_sym__type(sym) == STT_OBJECT &&
 136                 sym->st_name != 0 &&
 137                 sym->st_shndx != SHN_UNDEF;
 138 }
 139
 140 static inline int elf_sym__is_label(const GElf_Sym *sym)
 141 {
 142         return elf_sym__type(sym) == STT_NOTYPE &&
 143                 sym->st_name != 0 &&
 144                 sym->st_shndx != SHN_UNDEF &&
 145                 sym->st_shndx != SHN_ABS &&
 146                 elf_sym__visibility(sym) != STV_HIDDEN &&
 147                 elf_sym__visibility(sym) != STV_INTERNAL;
 148 }
 149
 150 static bool elf_sym__filter(GElf_Sym *sym)
 151 {
 152         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 153 }
 154
 155 static inline const char *elf_sym__name(const GElf_Sym *sym,
 156                                         const Elf_Data *symstrs)
 157 {
 158         return symstrs->d_buf + sym->st_name;
 159 }
 160
 161 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 162                                         const Elf_Data *secstrs)
 163 {
 164         return secstrs->d_buf + shdr->sh_name;
 165 }
 166
 167 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 168                                         const Elf_Data *secstrs)
 169 {
 170         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 171 }
 172
 173 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 174                                     const Elf_Data *secstrs)
 175 {
 176         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 177 }
 178
 179 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 180 {
 181         return elf_sec__is_text(shdr, secstrs) ||
 182                elf_sec__is_data(shdr, secstrs);
 183 }
 184
 185 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 186 {
 187         Elf_Scn *sec = NULL;
 188         GElf_Shdr shdr;
 189         size_t cnt = 1;
 190
 191         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 192                 gelf_getshdr(sec, &shdr);
 193
 194                 if ((addr >= shdr.sh_addr) &&
 195                     (addr < (shdr.sh_addr + shdr.sh_size)))
 196                         return cnt;
 197
 198                 ++cnt;
 199         }
 200
 201         return -1;
 202 }
 203
 204 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 205                              GElf_Shdr *shp, const char *name, size_t *idx)
 206 {
 207         Elf_Scn *sec = NULL;
 208         size_t cnt = 1;
 209
 210         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 211         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 212                 return NULL;
 213
 214         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 215                 char *str;
 216
 217                 gelf_getshdr(sec, shp);
 218                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 219                 if (str && !strcmp(name, str)) {
 220                         if (idx)
 221                                 *idx = cnt;
 222                         return sec;
 223                 }
 224                 ++cnt;
 225         }
 226
 227         return NULL;
 228 }
 229
 230 static bool want_demangle(bool is_kernel_sym)
 231 {
 232         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 233 }
 234
 235 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 236 {
 237         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 238         char *demangled = NULL;
 239
 240         /*
 241          * We need to figure out if the object was created from C++ sources
 242          * DWARF DW_compile_unit has this, but we don't always have access
 243          * to it...
 244          */
 245         if (!want_demangle(dso->kernel || kmodule))
 246             return demangled;
 247
 248         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 249         if (demangled == NULL)
 250                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 251         else if (rust_is_mangled(demangled))
 252                 /*
 253                     * Input to Rust demangling is the BFD-demangled
 254                     * name which it Rust-demangles in place.
 255                     */
 256                 rust_demangle_sym(demangled);
 257
 258         return demangled;
 259 }
 260
 261 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 262         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 263              idx < nr_entries; \
 264              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 265
 266 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 267         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 268              idx < nr_entries; \
 269              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 270
 271 /*
 272  * We need to check if we have a .dynsym, so that we can handle the
 273  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 274  * .dynsym or .symtab).
 275  * And always look at the original dso, not at debuginfo packages, that
 276  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 277  */
 278 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 279 {
 280         uint32_t nr_rel_entries, idx;
 281         GElf_Sym sym;
 282         u64 plt_offset, plt_header_size, plt_entry_size;
 283         GElf_Shdr shdr_plt;
 284         struct symbol *f;
 285         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 286         Elf_Data *reldata, *syms, *symstrs;
 287         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 288         size_t dynsym_idx;
 289         GElf_Ehdr ehdr;
 290         char sympltname[1024];
 291         Elf *elf;
 292         int nr = 0, symidx, err = 0;
 293
 294         if (!ss->dynsym)
 295                 return 0;
 296
 297         elf = ss->elf;
 298         ehdr = ss->ehdr;
 299
 300         scn_dynsym = ss->dynsym;
 301         shdr_dynsym = ss->dynshdr;
 302         dynsym_idx = ss->dynsym_idx;
 303
 304         if (scn_dynsym == NULL)
 305                 goto out_elf_end;
 306
 307         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 308                                           ".rela.plt", NULL);
 309         if (scn_plt_rel == NULL) {
 310                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 311                                                   ".rel.plt", NULL);
 312                 if (scn_plt_rel == NULL)
 313                         goto out_elf_end;
 314         }
 315
 316         err = -1;
 317
 318         if (shdr_rel_plt.sh_link != dynsym_idx)
 319                 goto out_elf_end;
 320
 321         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 322                 goto out_elf_end;
 323
 324         /*
 325          * Fetch the relocation section to find the idxes to the GOT
 326          * and the symbols in the .dynsym they refer to.
 327          */
 328         reldata = elf_getdata(scn_plt_rel, NULL);
 329         if (reldata == NULL)
 330                 goto out_elf_end;
 331
 332         syms = elf_getdata(scn_dynsym, NULL);
 333         if (syms == NULL)
 334                 goto out_elf_end;
 335
 336         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 337         if (scn_symstrs == NULL)
 338                 goto out_elf_end;
 339
 340         symstrs = elf_getdata(scn_symstrs, NULL);
 341         if (symstrs == NULL)
 342                 goto out_elf_end;
 343
 344         if (symstrs->d_size == 0)
 345                 goto out_elf_end;
 346
 347         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 348         plt_offset = shdr_plt.sh_offset;
 349         switch (ehdr.e_machine) {
 350                 case EM_ARM:
 351                         plt_header_size = 20;
 352                         plt_entry_size = 12;
 353                         break;
 354
 355                 case EM_AARCH64:
 356                         plt_header_size = 32;
 357                         plt_entry_size = 16;
 358                         break;
 359
 360                 case EM_SPARC:
 361                         plt_header_size = 48;
 362                         plt_entry_size = 12;
 363                         break;
 364
 365                 case EM_SPARCV9:
 366                         plt_header_size = 128;
 367                         plt_entry_size = 32;
 368                         break;
 369
 370                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 371                         plt_header_size = shdr_plt.sh_entsize;
 372                         plt_entry_size = shdr_plt.sh_entsize;
 373                         break;
 374         }
 375         plt_offset += plt_header_size;
 376
 377         if (shdr_rel_plt.sh_type == SHT_RELA) {
 378                 GElf_Rela pos_mem, *pos;
 379
 380                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 381                                            nr_rel_entries) {
 382                         const char *elf_name = NULL;
 383                         char *demangled = NULL;
 384                         symidx = GELF_R_SYM(pos->r_info);
 385                         gelf_getsym(syms, symidx, &sym);
 386
 387                         elf_name = elf_sym__name(&sym, symstrs);
 388                         demangled = demangle_sym(dso, 0, elf_name);
 389                         if (demangled != NULL)
 390                                 elf_name = demangled;
 391                         snprintf(sympltname, sizeof(sympltname),
 392                                  "%s@plt", elf_name);
 393                         free(demangled);
 394
 395                         f = symbol__new(plt_offset, plt_entry_size,
 396                                         STB_GLOBAL, STT_FUNC, sympltname);
 397                         if (!f)
 398                                 goto out_elf_end;
 399
 400                         plt_offset += plt_entry_size;
 401                         symbols__insert(&dso->symbols, f);
 402                         ++nr;
 403                 }
 404         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 405                 GElf_Rel pos_mem, *pos;
 406                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 407                                           nr_rel_entries) {
 408                         const char *elf_name = NULL;
 409                         char *demangled = NULL;
 410                         symidx = GELF_R_SYM(pos->r_info);
 411                         gelf_getsym(syms, symidx, &sym);
 412
 413                         elf_name = elf_sym__name(&sym, symstrs);
 414                         demangled = demangle_sym(dso, 0, elf_name);
 415                         if (demangled != NULL)
 416                                 elf_name = demangled;
 417                         snprintf(sympltname, sizeof(sympltname),
 418                                  "%s@plt", elf_name);
 419                         free(demangled);
 420
 421                         f = symbol__new(plt_offset, plt_entry_size,
 422                                         STB_GLOBAL, STT_FUNC, sympltname);
 423                         if (!f)
 424                                 goto out_elf_end;
 425
 426                         plt_offset += plt_entry_size;
 427                         symbols__insert(&dso->symbols, f);
 428                         ++nr;
 429                 }
 430         }
 431
 432         err = 0;
 433 out_elf_end:
 434         if (err == 0)
 435                 return nr;
 436         pr_debug("%s: problems reading %s PLT info.\n",
 437                  __func__, dso->long_name);
 438         return 0;
 439 }
 440
 441 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 442 {
 443         return demangle_sym(dso, kmodule, elf_name);
 444 }
 445
 446 /*
 447  * Align offset to 4 bytes as needed for note name and descriptor data.
 448  */
 449 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 450
 451 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 452 {
 453         int err = -1;
 454         GElf_Ehdr ehdr;
 455         GElf_Shdr shdr;
 456         Elf_Data *data;
 457         Elf_Scn *sec;
 458         Elf_Kind ek;
 459         void *ptr;
 460
 461         if (size < BUILD_ID_SIZE)
 462                 goto out;
 463
 464         ek = elf_kind(elf);
 465         if (ek != ELF_K_ELF)
 466                 goto out;
 467
 468         if (gelf_getehdr(elf, &ehdr) == NULL) {
 469                 pr_err("%s: cannot get elf header.\n", __func__);
 470                 goto out;
 471         }
 472
 473         /*
 474          * Check following sections for notes:
 475          *   '.note.gnu.build-id'
 476          *   '.notes'
 477          *   '.note' (VDSO specific)
 478          */
 479         do {
 480                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 481                                           ".note.gnu.build-id", NULL);
 482                 if (sec)
 483                         break;
 484
 485                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 486                                           ".notes", NULL);
 487                 if (sec)
 488                         break;
 489
 490                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 491                                           ".note", NULL);
 492                 if (sec)
 493                         break;
 494
 495                 return err;
 496
 497         } while (0);
 498
 499         data = elf_getdata(sec, NULL);
 500         if (data == NULL)
 501                 goto out;
 502
 503         ptr = data->d_buf;
 504         while (ptr < (data->d_buf + data->d_size)) {
 505                 GElf_Nhdr *nhdr = ptr;
 506                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 507                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 508                 const char *name;
 509
 510                 ptr += sizeof(*nhdr);
 511                 name = ptr;
 512                 ptr += namesz;
 513                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 514                     nhdr->n_namesz == sizeof("GNU")) {
 515                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 516                                 size_t sz = min(size, descsz);
 517                                 memcpy(bf, ptr, sz);
 518                                 memset(bf + sz, 0, size - sz);
 519                                 err = descsz;
 520                                 break;
 521                         }
 522                 }
 523                 ptr += descsz;
 524         }
 525
 526 out:
 527         return err;
 528 }
 529
 530 int filename__read_build_id(const char *filename, void *bf, size_t size)
 531 {
 532         int fd, err = -1;
 533         Elf *elf;
 534
 535         if (size < BUILD_ID_SIZE)
 536                 goto out;
 537
 538         fd = open(filename, O_RDONLY);
 539         if (fd < 0)
 540                 goto out;
 541
 542         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 543         if (elf == NULL) {
 544                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 545                 goto out_close;
 546         }
 547
 548         err = elf_read_build_id(elf, bf, size);
 549
 550         elf_end(elf);
 551 out_close:
 552         close(fd);
 553 out:
 554         return err;
 555 }
 556
 557 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 558 {
 559         int fd, err = -1;
 560
 561         if (size < BUILD_ID_SIZE)
 562                 goto out;
 563
 564         fd = open(filename, O_RDONLY);
 565         if (fd < 0)
 566                 goto out;
 567
 568         while (1) {
 569                 char bf[BUFSIZ];
 570                 GElf_Nhdr nhdr;
 571                 size_t namesz, descsz;
 572
 573                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 574                         break;
 575
 576                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 577                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 578                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 579                     nhdr.n_namesz == sizeof("GNU")) {
 580                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 581                                 break;
 582                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 583                                 size_t sz = min(descsz, size);
 584                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 585                                         memset(build_id + sz, 0, size - sz);
 586                                         err = 0;
 587                                         break;
 588                                 }
 589                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 590                                 break;
 591                 } else {
 592                         int n = namesz + descsz;
 593
 594                         if (n > (int)sizeof(bf)) {
 595                                 n = sizeof(bf);
 596                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 597                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 598                         }
 599                         if (read(fd, bf, n) != n)
 600                                 break;
 601                 }
 602         }
 603         close(fd);
 604 out:
 605         return err;
 606 }
 607
 608 int filename__read_debuglink(const char *filename, char *debuglink,
 609                              size_t size)
 610 {
 611         int fd, err = -1;
 612         Elf *elf;
 613         GElf_Ehdr ehdr;
 614         GElf_Shdr shdr;
 615         Elf_Data *data;
 616         Elf_Scn *sec;
 617         Elf_Kind ek;
 618
 619         fd = open(filename, O_RDONLY);
 620         if (fd < 0)
 621                 goto out;
 622
 623         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 624         if (elf == NULL) {
 625                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 626                 goto out_close;
 627         }
 628
 629         ek = elf_kind(elf);
 630         if (ek != ELF_K_ELF)
 631                 goto out_elf_end;
 632
 633         if (gelf_getehdr(elf, &ehdr) == NULL) {
 634                 pr_err("%s: cannot get elf header.\n", __func__);
 635                 goto out_elf_end;
 636         }
 637
 638         sec = elf_section_by_name(elf, &ehdr, &shdr,
 639                                   ".gnu_debuglink", NULL);
 640         if (sec == NULL)
 641                 goto out_elf_end;
 642
 643         data = elf_getdata(sec, NULL);
 644         if (data == NULL)
 645                 goto out_elf_end;
 646
 647         /* the start of this section is a zero-terminated string */
 648         strncpy(debuglink, data->d_buf, size);
 649
 650         err = 0;
 651
 652 out_elf_end:
 653         elf_end(elf);
 654 out_close:
 655         close(fd);
 656 out:
 657         return err;
 658 }
 659
 660 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 661 {
 662         static unsigned int const endian = 1;
 663
 664         dso->needs_swap = DSO_SWAP__NO;
 665
 666         switch (eidata) {
 667         case ELFDATA2LSB:
 668                 /* We are big endian, DSO is little endian. */
 669                 if (*(unsigned char const *)&endian != 1)
 670                         dso->needs_swap = DSO_SWAP__YES;
 671                 break;
 672
 673         case ELFDATA2MSB:
 674                 /* We are little endian, DSO is big endian. */
 675                 if (*(unsigned char const *)&endian != 0)
 676                         dso->needs_swap = DSO_SWAP__YES;
 677                 break;
 678
 679         default:
 680                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 681                 return -EINVAL;
 682         }
 683
 684         return 0;
 685 }
 686
 687 bool symsrc__possibly_runtime(struct symsrc *ss)
 688 {
 689         return ss->dynsym || ss->opdsec;
 690 }
 691
 692 bool symsrc__has_symtab(struct symsrc *ss)
 693 {
 694         return ss->symtab != NULL;
 695 }
 696
 697 void symsrc__destroy(struct symsrc *ss)
 698 {
 699         zfree(&ss->name);
 700         elf_end(ss->elf);
 701         close(ss->fd);
 702 }
 703
 704 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 705 {
 706         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 707 }
 708
 709 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 710                  enum dso_binary_type type)
 711 {
 712         GElf_Ehdr ehdr;
 713         Elf *elf;
 714         int fd;
 715
 716         if (dso__needs_decompress(dso)) {
 717                 fd = dso__decompress_kmodule_fd(dso, name);
 718                 if (fd < 0)
 719                         return -1;
 720
 721                 type = dso->symtab_type;
 722         } else {
 723                 fd = open(name, O_RDONLY);
 724                 if (fd < 0) {
 725                         dso->load_errno = errno;
 726                         return -1;
 727                 }
 728         }
 729
 730         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 731         if (elf == NULL) {
 732                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 733                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 734                 goto out_close;
 735         }
 736
 737         if (gelf_getehdr(elf, &ehdr) == NULL) {
 738                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 739                 pr_debug("%s: cannot get elf header.\n", __func__);
 740                 goto out_elf_end;
 741         }
 742
 743         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 744                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 745                 goto out_elf_end;
 746         }
 747
 748         /* Always reject images with a mismatched build-id: */
 749         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 750                 u8 build_id[BUILD_ID_SIZE];
 751
 752                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 753                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 754                         goto out_elf_end;
 755                 }
 756
 757                 if (!dso__build_id_equal(dso, build_id)) {
 758                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 759                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 760                         goto out_elf_end;
 761                 }
 762         }
 763
 764         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 765
 766         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 767                         NULL);
 768         if (ss->symshdr.sh_type != SHT_SYMTAB)
 769                 ss->symtab = NULL;
 770
 771         ss->dynsym_idx = 0;
 772         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 773                         &ss->dynsym_idx);
 774         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 775                 ss->dynsym = NULL;
 776
 777         ss->opdidx = 0;
 778         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 779                         &ss->opdidx);
 780         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 781                 ss->opdsec = NULL;
 782
 783         if (dso->kernel == DSO_TYPE_USER)
 784                 ss->adjust_symbols = true;
 785         else
 786                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 787
 788         ss->name   = strdup(name);
 789         if (!ss->name) {
 790                 dso->load_errno = errno;
 791                 goto out_elf_end;
 792         }
 793
 794         ss->elf    = elf;
 795         ss->fd     = fd;
 796         ss->ehdr   = ehdr;
 797         ss->type   = type;
 798
 799         return 0;
 800
 801 out_elf_end:
 802         elf_end(elf);
 803 out_close:
 804         close(fd);
 805         return -1;
 806 }
 807
 808 /**
 809  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 810  * @kmap: kernel maps and relocation reference symbol
 811  *
 812  * This function returns %true if we are dealing with the kernel maps and the
 813  * relocation reference symbol has not yet been found.  Otherwise %false is
 814  * returned.
 815  */
 816 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 817 {
 818         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 819                !kmap->ref_reloc_sym->unrelocated_addr;
 820 }
 821
 822 /**
 823  * ref_reloc - kernel relocation offset.
 824  * @kmap: kernel maps and relocation reference symbol
 825  *
 826  * This function returns the offset of kernel addresses as determined by using
 827  * the relocation reference symbol i.e. if the kernel has not been relocated
 828  * then the return value is zero.
 829  */
 830 static u64 ref_reloc(struct kmap *kmap)
 831 {
 832         if (kmap && kmap->ref_reloc_sym &&
 833             kmap->ref_reloc_sym->unrelocated_addr)
 834                 return kmap->ref_reloc_sym->addr -
 835                        kmap->ref_reloc_sym->unrelocated_addr;
 836         return 0;
 837 }
 838
 839 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 840                 GElf_Sym *sym __maybe_unused) { }
 841
 842 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 843                                       GElf_Sym *sym, GElf_Shdr *shdr,
 844                                       struct map_groups *kmaps, struct kmap *kmap,
 845                                       struct dso **curr_dsop, struct map **curr_mapp,
 846                                       const char *section_name,
 847                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 848 {
 849         struct dso *curr_dso = *curr_dsop;
 850         struct map *curr_map;
 851         char dso_name[PATH_MAX];
 852
 853         /* Adjust symbol to map to file offset */
 854         if (adjust_kernel_syms)
 855                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 856
 857         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 858                 return 0;
 859
 860         if (strcmp(section_name, ".text") == 0) {
 861                 /*
 862                  * The initial kernel mapping is based on
 863                  * kallsyms and identity maps.  Overwrite it to
 864                  * map to the kernel dso.
 865                  */
 866                 if (*remap_kernel && dso->kernel) {
 867                         *remap_kernel = false;
 868                         map->start = shdr->sh_addr + ref_reloc(kmap);
 869                         map->end = map->start + shdr->sh_size;
 870                         map->pgoff = shdr->sh_offset;
 871                         map->map_ip = map__map_ip;
 872                         map->unmap_ip = map__unmap_ip;
 873                         /* Ensure maps are correctly ordered */
 874                         if (kmaps) {
 875                                 map__get(map);
 876                                 map_groups__remove(kmaps, map);
 877                                 map_groups__insert(kmaps, map);
 878                                 map__put(map);
 879                         }
 880                 }
 881
 882                 /*
 883                  * The initial module mapping is based on
 884                  * /proc/modules mapped to offset zero.
 885                  * Overwrite it to map to the module dso.
 886                  */
 887                 if (*remap_kernel && kmodule) {
 888                         *remap_kernel = false;
 889                         map->pgoff = shdr->sh_offset;
 890                 }
 891
 892                 *curr_mapp = map;
 893                 *curr_dsop = dso;
 894                 return 0;
 895         }
 896
 897         if (!kmap)
 898                 return 0;
 899
 900         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 901
 902         curr_map = map_groups__find_by_name(kmaps, dso_name);
 903         if (curr_map == NULL) {
 904                 u64 start = sym->st_value;
 905
 906                 if (kmodule)
 907                         start += map->start + shdr->sh_offset;
 908
 909                 curr_dso = dso__new(dso_name);
 910                 if (curr_dso == NULL)
 911                         return -1;
 912                 curr_dso->kernel = dso->kernel;
 913                 curr_dso->long_name = dso->long_name;
 914                 curr_dso->long_name_len = dso->long_name_len;
 915                 curr_map = map__new2(start, curr_dso);
 916                 dso__put(curr_dso);
 917                 if (curr_map == NULL)
 918                         return -1;
 919
 920                 if (adjust_kernel_syms) {
 921                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 922                         curr_map->end    = curr_map->start + shdr->sh_size;
 923                         curr_map->pgoff  = shdr->sh_offset;
 924                 } else {
 925                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 926                 }
 927                 curr_dso->symtab_type = dso->symtab_type;
 928                 map_groups__insert(kmaps, curr_map);
 929                 /*
 930                  * Add it before we drop the referece to curr_map, i.e. while
 931                  * we still are sure to have a reference to this DSO via
 932                  * *curr_map->dso.
 933                  */
 934                 dsos__add(&map->groups->machine->dsos, curr_dso);
 935                 /* kmaps already got it */
 936                 map__put(curr_map);
 937                 dso__set_loaded(curr_dso);
 938                 *curr_mapp = curr_map;
 939                 *curr_dsop = curr_dso;
 940         } else
 941                 *curr_dsop = curr_map->dso;
 942
 943         return 0;
 944 }
 945
 946 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 947                   struct symsrc *runtime_ss, int kmodule)
 948 {
 949         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 950         struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
 951         struct map *curr_map = map;
 952         struct dso *curr_dso = dso;
 953         Elf_Data *symstrs, *secstrs;
 954         uint32_t nr_syms;
 955         int err = -1;
 956         uint32_t idx;
 957         GElf_Ehdr ehdr;
 958         GElf_Shdr shdr;
 959         GElf_Shdr tshdr;
 960         Elf_Data *syms, *opddata = NULL;
 961         GElf_Sym sym;
 962         Elf_Scn *sec, *sec_strndx;
 963         Elf *elf;
 964         int nr = 0;
 965         bool remap_kernel = false, adjust_kernel_syms = false;
 966
 967         if (kmap && !kmaps)
 968                 return -1;
 969
 970         dso->symtab_type = syms_ss->type;
 971         dso->is_64_bit = syms_ss->is_64_bit;
 972         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 973
 974         /*
 975          * Modules may already have symbols from kallsyms, but those symbols
 976          * have the wrong values for the dso maps, so remove them.
 977          */
 978         if (kmodule && syms_ss->symtab)
 979                 symbols__delete(&dso->symbols);
 980
 981         if (!syms_ss->symtab) {
 982                 /*
 983                  * If the vmlinux is stripped, fail so we will fall back
 984                  * to using kallsyms. The vmlinux runtime symbols aren't
 985                  * of much use.
 986                  */
 987                 if (dso->kernel)
 988                         goto out_elf_end;
 989
 990                 syms_ss->symtab  = syms_ss->dynsym;
 991                 syms_ss->symshdr = syms_ss->dynshdr;
 992         }
 993
 994         elf = syms_ss->elf;
 995         ehdr = syms_ss->ehdr;
 996         sec = syms_ss->symtab;
 997         shdr = syms_ss->symshdr;
 998
 999         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1000                                 ".text", NULL))
1001                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1002
1003         if (runtime_ss->opdsec)
1004                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1005
1006         syms = elf_getdata(sec, NULL);
1007         if (syms == NULL)
1008                 goto out_elf_end;
1009
1010         sec = elf_getscn(elf, shdr.sh_link);
1011         if (sec == NULL)
1012                 goto out_elf_end;
1013
1014         symstrs = elf_getdata(sec, NULL);
1015         if (symstrs == NULL)
1016                 goto out_elf_end;
1017
1018         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1019         if (sec_strndx == NULL)
1020                 goto out_elf_end;
1021
1022         secstrs = elf_getdata(sec_strndx, NULL);
1023         if (secstrs == NULL)
1024                 goto out_elf_end;
1025
1026         nr_syms = shdr.sh_size / shdr.sh_entsize;
1027
1028         memset(&sym, 0, sizeof(sym));
1029
1030         /*
1031          * The kernel relocation symbol is needed in advance in order to adjust
1032          * kernel maps correctly.
1033          */
1034         if (ref_reloc_sym_not_found(kmap)) {
1035                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1036                         const char *elf_name = elf_sym__name(&sym, symstrs);
1037
1038                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1039                                 continue;
1040                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1041                         map->reloc = kmap->ref_reloc_sym->addr -
1042                                      kmap->ref_reloc_sym->unrelocated_addr;
1043                         break;
1044                 }
1045         }
1046
1047         /*
1048          * Handle any relocation of vdso necessary because older kernels
1049          * attempted to prelink vdso to its virtual address.
1050          */
1051         if (dso__is_vdso(dso))
1052                 map->reloc = map->start - dso->text_offset;
1053
1054         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1055         /*
1056          * Initial kernel and module mappings do not map to the dso.
1057          * Flag the fixups.
1058          */
1059         if (dso->kernel || kmodule) {
1060                 remap_kernel = true;
1061                 adjust_kernel_syms = dso->adjust_symbols;
1062         }
1063         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1064                 struct symbol *f;
1065                 const char *elf_name = elf_sym__name(&sym, symstrs);
1066                 char *demangled = NULL;
1067                 int is_label = elf_sym__is_label(&sym);
1068                 const char *section_name;
1069                 bool used_opd = false;
1070
1071                 if (!is_label && !elf_sym__filter(&sym))
1072                         continue;
1073
1074                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1075                  * don't identify functions, so will confuse the profile
1076                  * output: */
1077                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1078                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1079                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1080                                 continue;
1081                 }
1082
1083                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1084                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1085                         u64 *opd = opddata->d_buf + offset;
1086                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1087                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1088                                         sym.st_value);
1089                         used_opd = true;
1090                 }
1091                 /*
1092                  * When loading symbols in a data mapping, ABS symbols (which
1093                  * has a value of SHN_ABS in its st_shndx) failed at
1094                  * elf_getscn().  And it marks the loading as a failure so
1095                  * already loaded symbols cannot be fixed up.
1096                  *
1097                  * I'm not sure what should be done. Just ignore them for now.
1098                  * - Namhyung Kim
1099                  */
1100                 if (sym.st_shndx == SHN_ABS)
1101                         continue;
1102
1103                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1104                 if (!sec)
1105                         goto out_elf_end;
1106
1107                 gelf_getshdr(sec, &shdr);
1108
1109                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1110                         continue;
1111
1112                 section_name = elf_sec__name(&shdr, secstrs);
1113
1114                 /* On ARM, symbols for thumb functions have 1 added to
1115                  * the symbol address as a flag - remove it */
1116                 if ((ehdr.e_machine == EM_ARM) &&
1117                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1118                     (sym.st_value & 1))
1119                         --sym.st_value;
1120
1121                 if (dso->kernel || kmodule) {
1122                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1123                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1124                                 goto out_elf_end;
1125                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1126                            (!used_opd && syms_ss->adjust_symbols)) {
1127                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1128                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1129                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1130                                   (u64)shdr.sh_offset);
1131                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1132                 }
1133
1134                 demangled = demangle_sym(dso, kmodule, elf_name);
1135                 if (demangled != NULL)
1136                         elf_name = demangled;
1137
1138                 f = symbol__new(sym.st_value, sym.st_size,
1139                                 GELF_ST_BIND(sym.st_info),
1140                                 GELF_ST_TYPE(sym.st_info), elf_name);
1141                 free(demangled);
1142                 if (!f)
1143                         goto out_elf_end;
1144
1145                 arch__sym_update(f, &sym);
1146
1147                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1148                 nr++;
1149         }
1150
1151         /*
1152          * For misannotated, zeroed, ASM function sizes.
1153          */
1154         if (nr > 0) {
1155                 symbols__fixup_end(&dso->symbols);
1156                 symbols__fixup_duplicate(&dso->symbols);
1157                 if (kmap) {
1158                         /*
1159                          * We need to fixup this here too because we create new
1160                          * maps here, for things like vsyscall sections.
1161                          */
1162                         map_groups__fixup_end(kmaps);
1163                 }
1164         }
1165         err = nr;
1166 out_elf_end:
1167         return err;
1168 }
1169
1170 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1171 {
1172         GElf_Phdr phdr;
1173         size_t i, phdrnum;
1174         int err;
1175         u64 sz;
1176
1177         if (elf_getphdrnum(elf, &phdrnum))
1178                 return -1;
1179
1180         for (i = 0; i < phdrnum; i++) {
1181                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1182                         return -1;
1183                 if (phdr.p_type != PT_LOAD)
1184                         continue;
1185                 if (exe) {
1186                         if (!(phdr.p_flags & PF_X))
1187                                 continue;
1188                 } else {
1189                         if (!(phdr.p_flags & PF_R))
1190                                 continue;
1191                 }
1192                 sz = min(phdr.p_memsz, phdr.p_filesz);
1193                 if (!sz)
1194                         continue;
1195                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1196                 if (err)
1197                         return err;
1198         }
1199         return 0;
1200 }
1201
1202 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1203                     bool *is_64_bit)
1204 {
1205         int err;
1206         Elf *elf;
1207
1208         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1209         if (elf == NULL)
1210                 return -1;
1211
1212         if (is_64_bit)
1213                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1214
1215         err = elf_read_maps(elf, exe, mapfn, data);
1216
1217         elf_end(elf);
1218         return err;
1219 }
1220
1221 enum dso_type dso__type_fd(int fd)
1222 {
1223         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1224         GElf_Ehdr ehdr;
1225         Elf_Kind ek;
1226         Elf *elf;
1227
1228         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1229         if (elf == NULL)
1230                 goto out;
1231
1232         ek = elf_kind(elf);
1233         if (ek != ELF_K_ELF)
1234                 goto out_end;
1235
1236         if (gelf_getclass(elf) == ELFCLASS64) {
1237                 dso_type = DSO__TYPE_64BIT;
1238                 goto out_end;
1239         }
1240
1241         if (gelf_getehdr(elf, &ehdr) == NULL)
1242                 goto out_end;
1243
1244         if (ehdr.e_machine == EM_X86_64)
1245                 dso_type = DSO__TYPE_X32BIT;
1246         else
1247                 dso_type = DSO__TYPE_32BIT;
1248 out_end:
1249         elf_end(elf);
1250 out:
1251         return dso_type;
1252 }
1253
1254 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1255 {
1256         ssize_t r;
1257         size_t n;
1258         int err = -1;
1259         char *buf = malloc(page_size);
1260
1261         if (buf == NULL)
1262                 return -1;
1263
1264         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1265                 goto out;
1266
1267         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1268                 goto out;
1269
1270         while (len) {
1271                 n = page_size;
1272                 if (len < n)
1273                         n = len;
1274                 /* Use read because mmap won't work on proc files */
1275                 r = read(from, buf, n);
1276                 if (r < 0)
1277                         goto out;
1278                 if (!r)
1279                         break;
1280                 n = r;
1281                 r = write(to, buf, n);
1282                 if (r < 0)
1283                         goto out;
1284                 if ((size_t)r != n)
1285                         goto out;
1286                 len -= n;
1287         }
1288
1289         err = 0;
1290 out:
1291         free(buf);
1292         return err;
1293 }
1294
1295 struct kcore {
1296         int fd;
1297         int elfclass;
1298         Elf *elf;
1299         GElf_Ehdr ehdr;
1300 };
1301
1302 static int kcore__open(struct kcore *kcore, const char *filename)
1303 {
1304         GElf_Ehdr *ehdr;
1305
1306         kcore->fd = open(filename, O_RDONLY);
1307         if (kcore->fd == -1)
1308                 return -1;
1309
1310         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1311         if (!kcore->elf)
1312                 goto out_close;
1313
1314         kcore->elfclass = gelf_getclass(kcore->elf);
1315         if (kcore->elfclass == ELFCLASSNONE)
1316                 goto out_end;
1317
1318         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1319         if (!ehdr)
1320                 goto out_end;
1321
1322         return 0;
1323
1324 out_end:
1325         elf_end(kcore->elf);
1326 out_close:
1327         close(kcore->fd);
1328         return -1;
1329 }
1330
1331 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1332                        bool temp)
1333 {
1334         kcore->elfclass = elfclass;
1335
1336         if (temp)
1337                 kcore->fd = mkstemp(filename);
1338         else
1339                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1340         if (kcore->fd == -1)
1341                 return -1;
1342
1343         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1344         if (!kcore->elf)
1345                 goto out_close;
1346
1347         if (!gelf_newehdr(kcore->elf, elfclass))
1348                 goto out_end;
1349
1350         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1351
1352         return 0;
1353
1354 out_end:
1355         elf_end(kcore->elf);
1356 out_close:
1357         close(kcore->fd);
1358         unlink(filename);
1359         return -1;
1360 }
1361
1362 static void kcore__close(struct kcore *kcore)
1363 {
1364         elf_end(kcore->elf);
1365         close(kcore->fd);
1366 }
1367
1368 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1369 {
1370         GElf_Ehdr *ehdr = &to->ehdr;
1371         GElf_Ehdr *kehdr = &from->ehdr;
1372
1373         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1374         ehdr->e_type      = kehdr->e_type;
1375         ehdr->e_machine   = kehdr->e_machine;
1376         ehdr->e_version   = kehdr->e_version;
1377         ehdr->e_entry     = 0;
1378         ehdr->e_shoff     = 0;
1379         ehdr->e_flags     = kehdr->e_flags;
1380         ehdr->e_phnum     = count;
1381         ehdr->e_shentsize = 0;
1382         ehdr->e_shnum     = 0;
1383         ehdr->e_shstrndx  = 0;
1384
1385         if (from->elfclass == ELFCLASS32) {
1386                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1387                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1388                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1389         } else {
1390                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1391                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1392                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1393         }
1394
1395         if (!gelf_update_ehdr(to->elf, ehdr))
1396                 return -1;
1397
1398         if (!gelf_newphdr(to->elf, count))
1399                 return -1;
1400
1401         return 0;
1402 }
1403
1404 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1405                            u64 addr, u64 len)
1406 {
1407         GElf_Phdr phdr = {
1408                 .p_type         = PT_LOAD,
1409                 .p_flags        = PF_R | PF_W | PF_X,
1410                 .p_offset       = offset,
1411                 .p_vaddr        = addr,
1412                 .p_paddr        = 0,
1413                 .p_filesz       = len,
1414                 .p_memsz        = len,
1415                 .p_align        = page_size,
1416         };
1417
1418         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1419                 return -1;
1420
1421         return 0;
1422 }
1423
1424 static off_t kcore__write(struct kcore *kcore)
1425 {
1426         return elf_update(kcore->elf, ELF_C_WRITE);
1427 }
1428
1429 struct phdr_data {
1430         off_t offset;
1431         off_t rel;
1432         u64 addr;
1433         u64 len;
1434         struct list_head node;
1435         struct phdr_data *remaps;
1436 };
1437
1438 struct sym_data {
1439         u64 addr;
1440         struct list_head node;
1441 };
1442
1443 struct kcore_copy_info {
1444         u64 stext;
1445         u64 etext;
1446         u64 first_symbol;
1447         u64 last_symbol;
1448         u64 first_module;
1449         u64 last_module_symbol;
1450         size_t phnum;
1451         struct list_head phdrs;
1452         struct list_head syms;
1453 };
1454
1455 #define kcore_copy__for_each_phdr(k, p) \
1456         list_for_each_entry((p), &(k)->phdrs, node)
1457
1458 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1459 {
1460         struct phdr_data *p = zalloc(sizeof(*p));
1461
1462         if (p) {
1463                 p->addr   = addr;
1464                 p->len    = len;
1465                 p->offset = offset;
1466         }
1467
1468         return p;
1469 }
1470
1471 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1472                                                  u64 addr, u64 len,
1473                                                  off_t offset)
1474 {
1475         struct phdr_data *p = phdr_data__new(addr, len, offset);
1476
1477         if (p)
1478                 list_add_tail(&p->node, &kci->phdrs);
1479
1480         return p;
1481 }
1482
1483 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1484 {
1485         struct phdr_data *p, *tmp;
1486
1487         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1488                 list_del_init(&p->node);
1489                 free(p);
1490         }
1491 }
1492
1493 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1494                                             u64 addr)
1495 {
1496         struct sym_data *s = zalloc(sizeof(*s));
1497
1498         if (s) {
1499                 s->addr = addr;
1500                 list_add_tail(&s->node, &kci->syms);
1501         }
1502
1503         return s;
1504 }
1505
1506 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1507 {
1508         struct sym_data *s, *tmp;
1509
1510         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1511                 list_del_init(&s->node);
1512                 free(s);
1513         }
1514 }
1515
1516 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1517                                         u64 start)
1518 {
1519         struct kcore_copy_info *kci = arg;
1520
1521         if (!kallsyms__is_function(type))
1522                 return 0;
1523
1524         if (strchr(name, '[')) {
1525                 if (start > kci->last_module_symbol)
1526                         kci->last_module_symbol = start;
1527                 return 0;
1528         }
1529
1530         if (!kci->first_symbol || start < kci->first_symbol)
1531                 kci->first_symbol = start;
1532
1533         if (!kci->last_symbol || start > kci->last_symbol)
1534                 kci->last_symbol = start;
1535
1536         if (!strcmp(name, "_stext")) {
1537                 kci->stext = start;
1538                 return 0;
1539         }
1540
1541         if (!strcmp(name, "_etext")) {
1542                 kci->etext = start;
1543                 return 0;
1544         }
1545
1546         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1547                 return -1;
1548
1549         return 0;
1550 }
1551
1552 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1553                                       const char *dir)
1554 {
1555         char kallsyms_filename[PATH_MAX];
1556
1557         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1558
1559         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1560                 return -1;
1561
1562         if (kallsyms__parse(kallsyms_filename, kci,
1563                             kcore_copy__process_kallsyms) < 0)
1564                 return -1;
1565
1566         return 0;
1567 }
1568
1569 static int kcore_copy__process_modules(void *arg,
1570                                        const char *name __maybe_unused,
1571                                        u64 start, u64 size __maybe_unused)
1572 {
1573         struct kcore_copy_info *kci = arg;
1574
1575         if (!kci->first_module || start < kci->first_module)
1576                 kci->first_module = start;
1577
1578         return 0;
1579 }
1580
1581 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1582                                      const char *dir)
1583 {
1584         char modules_filename[PATH_MAX];
1585
1586         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1587
1588         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1589                 return -1;
1590
1591         if (modules__parse(modules_filename, kci,
1592                            kcore_copy__process_modules) < 0)
1593                 return -1;
1594
1595         return 0;
1596 }
1597
1598 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1599                            u64 pgoff, u64 s, u64 e)
1600 {
1601         u64 len, offset;
1602
1603         if (s < start || s >= end)
1604                 return 0;
1605
1606         offset = (s - start) + pgoff;
1607         len = e < end ? e - s : end - s;
1608
1609         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1610 }
1611
1612 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1613 {
1614         struct kcore_copy_info *kci = data;
1615         u64 end = start + len;
1616         struct sym_data *sdat;
1617
1618         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1619                 return -1;
1620
1621         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1622                             kci->last_module_symbol))
1623                 return -1;
1624
1625         list_for_each_entry(sdat, &kci->syms, node) {
1626                 u64 s = round_down(sdat->addr, page_size);
1627
1628                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1629                         return -1;
1630         }
1631
1632         return 0;
1633 }
1634
1635 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1636 {
1637         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1638                 return -1;
1639
1640         return 0;
1641 }
1642
1643 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1644 {
1645         struct phdr_data *p, *k = NULL;
1646         u64 kend;
1647
1648         if (!kci->stext)
1649                 return;
1650
1651         /* Find phdr that corresponds to the kernel map (contains stext) */
1652         kcore_copy__for_each_phdr(kci, p) {
1653                 u64 pend = p->addr + p->len - 1;
1654
1655                 if (p->addr <= kci->stext && pend >= kci->stext) {
1656                         k = p;
1657                         break;
1658                 }
1659         }
1660
1661         if (!k)
1662                 return;
1663
1664         kend = k->offset + k->len;
1665
1666         /* Find phdrs that remap the kernel */
1667         kcore_copy__for_each_phdr(kci, p) {
1668                 u64 pend = p->offset + p->len;
1669
1670                 if (p == k)
1671                         continue;
1672
1673                 if (p->offset >= k->offset && pend <= kend)
1674                         p->remaps = k;
1675         }
1676 }
1677
1678 static void kcore_copy__layout(struct kcore_copy_info *kci)
1679 {
1680         struct phdr_data *p;
1681         off_t rel = 0;
1682
1683         kcore_copy__find_remaps(kci);
1684
1685         kcore_copy__for_each_phdr(kci, p) {
1686                 if (!p->remaps) {
1687                         p->rel = rel;
1688                         rel += p->len;
1689                 }
1690                 kci->phnum += 1;
1691         }
1692
1693         kcore_copy__for_each_phdr(kci, p) {
1694                 struct phdr_data *k = p->remaps;
1695
1696                 if (k)
1697                         p->rel = p->offset - k->offset + k->rel;
1698         }
1699 }
1700
1701 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1702                                  Elf *elf)
1703 {
1704         if (kcore_copy__parse_kallsyms(kci, dir))
1705                 return -1;
1706
1707         if (kcore_copy__parse_modules(kci, dir))
1708                 return -1;
1709
1710         if (kci->stext)
1711                 kci->stext = round_down(kci->stext, page_size);
1712         else
1713                 kci->stext = round_down(kci->first_symbol, page_size);
1714
1715         if (kci->etext) {
1716                 kci->etext = round_up(kci->etext, page_size);
1717         } else if (kci->last_symbol) {
1718                 kci->etext = round_up(kci->last_symbol, page_size);
1719                 kci->etext += page_size;
1720         }
1721
1722         kci->first_module = round_down(kci->first_module, page_size);
1723
1724         if (kci->last_module_symbol) {
1725                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1726                                                    page_size);
1727                 kci->last_module_symbol += page_size;
1728         }
1729
1730         if (!kci->stext || !kci->etext)
1731                 return -1;
1732
1733         if (kci->first_module && !kci->last_module_symbol)
1734                 return -1;
1735
1736         if (kcore_copy__read_maps(kci, elf))
1737                 return -1;
1738
1739         kcore_copy__layout(kci);
1740
1741         return 0;
1742 }
1743
1744 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1745                                  const char *name)
1746 {
1747         char from_filename[PATH_MAX];
1748         char to_filename[PATH_MAX];
1749
1750         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1751         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1752
1753         return copyfile_mode(from_filename, to_filename, 0400);
1754 }
1755
1756 static int kcore_copy__unlink(const char *dir, const char *name)
1757 {
1758         char filename[PATH_MAX];
1759
1760         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1761
1762         return unlink(filename);
1763 }
1764
1765 static int kcore_copy__compare_fds(int from, int to)
1766 {
1767         char *buf_from;
1768         char *buf_to;
1769         ssize_t ret;
1770         size_t len;
1771         int err = -1;
1772
1773         buf_from = malloc(page_size);
1774         buf_to = malloc(page_size);
1775         if (!buf_from || !buf_to)
1776                 goto out;
1777
1778         while (1) {
1779                 /* Use read because mmap won't work on proc files */
1780                 ret = read(from, buf_from, page_size);
1781                 if (ret < 0)
1782                         goto out;
1783
1784                 if (!ret)
1785                         break;
1786
1787                 len = ret;
1788
1789                 if (readn(to, buf_to, len) != (int)len)
1790                         goto out;
1791
1792                 if (memcmp(buf_from, buf_to, len))
1793                         goto out;
1794         }
1795
1796         err = 0;
1797 out:
1798         free(buf_to);
1799         free(buf_from);
1800         return err;
1801 }
1802
1803 static int kcore_copy__compare_files(const char *from_filename,
1804                                      const char *to_filename)
1805 {
1806         int from, to, err = -1;
1807
1808         from = open(from_filename, O_RDONLY);
1809         if (from < 0)
1810                 return -1;
1811
1812         to = open(to_filename, O_RDONLY);
1813         if (to < 0)
1814                 goto out_close_from;
1815
1816         err = kcore_copy__compare_fds(from, to);
1817
1818         close(to);
1819 out_close_from:
1820         close(from);
1821         return err;
1822 }
1823
1824 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1825                                     const char *name)
1826 {
1827         char from_filename[PATH_MAX];
1828         char to_filename[PATH_MAX];
1829
1830         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1831         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1832
1833         return kcore_copy__compare_files(from_filename, to_filename);
1834 }
1835
1836 /**
1837  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1838  * @from_dir: from directory
1839  * @to_dir: to directory
1840  *
1841  * This function copies kallsyms, modules and kcore files from one directory to
1842  * another.  kallsyms and modules are copied entirely.  Only code segments are
1843  * copied from kcore.  It is assumed that two segments suffice: one for the
1844  * kernel proper and one for all the modules.  The code segments are determined
1845  * from kallsyms and modules files.  The kernel map starts at _stext or the
1846  * lowest function symbol, and ends at _etext or the highest function symbol.
1847  * The module map starts at the lowest module address and ends at the highest
1848  * module symbol.  Start addresses are rounded down to the nearest page.  End
1849  * addresses are rounded up to the nearest page.  An extra page is added to the
1850  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1851  * symbol too.  Because it contains only code sections, the resulting kcore is
1852  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1853  * is not the same for the kernel map and the modules map.  That happens because
1854  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1855  * kallsyms and modules files are compared with their copies to check that
1856  * modules have not been loaded or unloaded while the copies were taking place.
1857  *
1858  * Return: %0 on success, %-1 on failure.
1859  */
1860 int kcore_copy(const char *from_dir, const char *to_dir)
1861 {
1862         struct kcore kcore;
1863         struct kcore extract;
1864         int idx = 0, err = -1;
1865         off_t offset, sz;
1866         struct kcore_copy_info kci = { .stext = 0, };
1867         char kcore_filename[PATH_MAX];
1868         char extract_filename[PATH_MAX];
1869         struct phdr_data *p;
1870
1871         INIT_LIST_HEAD(&kci.phdrs);
1872         INIT_LIST_HEAD(&kci.syms);
1873
1874         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1875                 return -1;
1876
1877         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1878                 goto out_unlink_kallsyms;
1879
1880         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1881         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1882
1883         if (kcore__open(&kcore, kcore_filename))
1884                 goto out_unlink_modules;
1885
1886         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1887                 goto out_kcore_close;
1888
1889         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1890                 goto out_kcore_close;
1891
1892         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1893                 goto out_extract_close;
1894
1895         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1896                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1897         offset = round_up(offset, page_size);
1898
1899         kcore_copy__for_each_phdr(&kci, p) {
1900                 off_t offs = p->rel + offset;
1901
1902                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1903                         goto out_extract_close;
1904         }
1905
1906         sz = kcore__write(&extract);
1907         if (sz < 0 || sz > offset)
1908                 goto out_extract_close;
1909
1910         kcore_copy__for_each_phdr(&kci, p) {
1911                 off_t offs = p->rel + offset;
1912
1913                 if (p->remaps)
1914                         continue;
1915                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1916                         goto out_extract_close;
1917         }
1918
1919         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1920                 goto out_extract_close;
1921
1922         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1923                 goto out_extract_close;
1924
1925         err = 0;
1926
1927 out_extract_close:
1928         kcore__close(&extract);
1929         if (err)
1930                 unlink(extract_filename);
1931 out_kcore_close:
1932         kcore__close(&kcore);
1933 out_unlink_modules:
1934         if (err)
1935                 kcore_copy__unlink(to_dir, "modules");
1936 out_unlink_kallsyms:
1937         if (err)
1938                 kcore_copy__unlink(to_dir, "kallsyms");
1939
1940         kcore_copy__free_phdrs(&kci);
1941         kcore_copy__free_syms(&kci);
1942
1943         return err;
1944 }
1945
1946 int kcore_extract__create(struct kcore_extract *kce)
1947 {
1948         struct kcore kcore;
1949         struct kcore extract;
1950         size_t count = 1;
1951         int idx = 0, err = -1;
1952         off_t offset = page_size, sz;
1953
1954         if (kcore__open(&kcore, kce->kcore_filename))
1955                 return -1;
1956
1957         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1958         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1959                 goto out_kcore_close;
1960
1961         if (kcore__copy_hdr(&kcore, &extract, count))
1962                 goto out_extract_close;
1963
1964         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1965                 goto out_extract_close;
1966
1967         sz = kcore__write(&extract);
1968         if (sz < 0 || sz > offset)
1969                 goto out_extract_close;
1970
1971         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1972                 goto out_extract_close;
1973
1974         err = 0;
1975
1976 out_extract_close:
1977         kcore__close(&extract);
1978         if (err)
1979                 unlink(kce->extract_filename);
1980 out_kcore_close:
1981         kcore__close(&kcore);
1982
1983         return err;
1984 }
1985
1986 void kcore_extract__delete(struct kcore_extract *kce)
1987 {
1988         unlink(kce->extract_filename);
1989 }
1990
1991 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1992
1993 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
1994 {
1995         if (!base_off)
1996                 return;
1997
1998         if (tmp->bit32)
1999                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2000                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2001                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2002         else
2003                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2004                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2005                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2006 }
2007
2008 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2009                               GElf_Addr base_off)
2010 {
2011         if (!base_off)
2012                 return;
2013
2014         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2015                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2016         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2017                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2018 }
2019
2020 /**
2021  * populate_sdt_note : Parse raw data and identify SDT note
2022  * @elf: elf of the opened file
2023  * @data: raw data of a section with description offset applied
2024  * @len: note description size
2025  * @type: type of the note
2026  * @sdt_notes: List to add the SDT note
2027  *
2028  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2029  * if its an SDT note, it appends to @sdt_notes list.
2030  */
2031 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2032                              struct list_head *sdt_notes)
2033 {
2034         const char *provider, *name, *args;
2035         struct sdt_note *tmp = NULL;
2036         GElf_Ehdr ehdr;
2037         GElf_Shdr shdr;
2038         int ret = -EINVAL;
2039
2040         union {
2041                 Elf64_Addr a64[NR_ADDR];
2042                 Elf32_Addr a32[NR_ADDR];
2043         } buf;
2044
2045         Elf_Data dst = {
2046                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2047                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2048                 .d_off = 0, .d_align = 0
2049         };
2050         Elf_Data src = {
2051                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2052                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2053                 .d_align = 0
2054         };
2055
2056         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2057         if (!tmp) {
2058                 ret = -ENOMEM;
2059                 goto out_err;
2060         }
2061
2062         INIT_LIST_HEAD(&tmp->note_list);
2063
2064         if (len < dst.d_size + 3)
2065                 goto out_free_note;
2066
2067         /* Translation from file representation to memory representation */
2068         if (gelf_xlatetom(*elf, &dst, &src,
2069                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2070                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2071                 goto out_free_note;
2072         }
2073
2074         /* Populate the fields of sdt_note */
2075         provider = data + dst.d_size;
2076
2077         name = (const char *)memchr(provider, '\0', data + len - provider);
2078         if (name++ == NULL)
2079                 goto out_free_note;
2080
2081         tmp->provider = strdup(provider);
2082         if (!tmp->provider) {
2083                 ret = -ENOMEM;
2084                 goto out_free_note;
2085         }
2086         tmp->name = strdup(name);
2087         if (!tmp->name) {
2088                 ret = -ENOMEM;
2089                 goto out_free_prov;
2090         }
2091
2092         args = memchr(name, '\0', data + len - name);
2093
2094         /*
2095          * There is no argument if:
2096          * - We reached the end of the note;
2097          * - There is not enough room to hold a potential string;
2098          * - The argument string is empty or just contains ':'.
2099          */
2100         if (args == NULL || data + len - args < 2 ||
2101                 args[1] == ':' || args[1] == '\0')
2102                 tmp->args = NULL;
2103         else {
2104                 tmp->args = strdup(++args);
2105                 if (!tmp->args) {
2106                         ret = -ENOMEM;
2107                         goto out_free_name;
2108                 }
2109         }
2110
2111         if (gelf_getclass(*elf) == ELFCLASS32) {
2112                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2113                 tmp->bit32 = true;
2114         } else {
2115                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2116                 tmp->bit32 = false;
2117         }
2118
2119         if (!gelf_getehdr(*elf, &ehdr)) {
2120                 pr_debug("%s : cannot get elf header.\n", __func__);
2121                 ret = -EBADF;
2122                 goto out_free_args;
2123         }
2124
2125         /* Adjust the prelink effect :
2126          * Find out the .stapsdt.base section.
2127          * This scn will help us to handle prelinking (if present).
2128          * Compare the retrieved file offset of the base section with the
2129          * base address in the description of the SDT note. If its different,
2130          * then accordingly, adjust the note location.
2131          */
2132         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2133                 sdt_adjust_loc(tmp, shdr.sh_offset);
2134
2135         /* Adjust reference counter offset */
2136         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2137                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2138
2139         list_add_tail(&tmp->note_list, sdt_notes);
2140         return 0;
2141
2142 out_free_args:
2143         zfree(&tmp->args);
2144 out_free_name:
2145         zfree(&tmp->name);
2146 out_free_prov:
2147         zfree(&tmp->provider);
2148 out_free_note:
2149         free(tmp);
2150 out_err:
2151         return ret;
2152 }
2153
2154 /**
2155  * construct_sdt_notes_list : constructs a list of SDT notes
2156  * @elf : elf to look into
2157  * @sdt_notes : empty list_head
2158  *
2159  * Scans the sections in 'elf' for the section
2160  * .note.stapsdt. It, then calls populate_sdt_note to find
2161  * out the SDT events and populates the 'sdt_notes'.
2162  */
2163 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2164 {
2165         GElf_Ehdr ehdr;
2166         Elf_Scn *scn = NULL;
2167         Elf_Data *data;
2168         GElf_Shdr shdr;
2169         size_t shstrndx, next;
2170         GElf_Nhdr nhdr;
2171         size_t name_off, desc_off, offset;
2172         int ret = 0;
2173
2174         if (gelf_getehdr(elf, &ehdr) == NULL) {
2175                 ret = -EBADF;
2176                 goto out_ret;
2177         }
2178         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2179                 ret = -EBADF;
2180                 goto out_ret;
2181         }
2182
2183         /* Look for the required section */
2184         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2185         if (!scn) {
2186                 ret = -ENOENT;
2187                 goto out_ret;
2188         }
2189
2190         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2191                 ret = -ENOENT;
2192                 goto out_ret;
2193         }
2194
2195         data = elf_getdata(scn, NULL);
2196
2197         /* Get the SDT notes */
2198         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2199                                               &desc_off)) > 0; offset = next) {
2200                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2201                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2202                             sizeof(SDT_NOTE_NAME))) {
2203                         /* Check the type of the note */
2204                         if (nhdr.n_type != SDT_NOTE_TYPE)
2205                                 goto out_ret;
2206
2207                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2208                                                 nhdr.n_descsz, sdt_notes);
2209                         if (ret < 0)
2210                                 goto out_ret;
2211                 }
2212         }
2213         if (list_empty(sdt_notes))
2214                 ret = -ENOENT;
2215
2216 out_ret:
2217         return ret;
2218 }
2219
2220 /**
2221  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2222  * @head : empty list_head
2223  * @target : file to find SDT notes from
2224  *
2225  * This opens the file, initializes
2226  * the ELF and then calls construct_sdt_notes_list.
2227  */
2228 int get_sdt_note_list(struct list_head *head, const char *target)
2229 {
2230         Elf *elf;
2231         int fd, ret;
2232
2233         fd = open(target, O_RDONLY);
2234         if (fd < 0)
2235                 return -EBADF;
2236
2237         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2238         if (!elf) {
2239                 ret = -EBADF;
2240                 goto out_close;
2241         }
2242         ret = construct_sdt_notes_list(elf, head);
2243         elf_end(elf);
2244 out_close:
2245         close(fd);
2246         return ret;
2247 }
2248
2249 /**
2250  * cleanup_sdt_note_list : free the sdt notes' list
2251  * @sdt_notes: sdt notes' list
2252  *
2253  * Free up the SDT notes in @sdt_notes.
2254  * Returns the number of SDT notes free'd.
2255  */
2256 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2257 {
2258         struct sdt_note *tmp, *pos;
2259         int nr_free = 0;
2260
2261         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2262                 list_del_init(&pos->note_list);
2263                 zfree(&pos->name);
2264                 zfree(&pos->provider);
2265                 free(pos);
2266                 nr_free++;
2267         }
2268         return nr_free;
2269 }
2270
2271 /**
2272  * sdt_notes__get_count: Counts the number of sdt events
2273  * @start: list_head to sdt_notes list
2274  *
2275  * Returns the number of SDT notes in a list
2276  */
2277 int sdt_notes__get_count(struct list_head *start)
2278 {
2279         struct sdt_note *sdt_ptr;
2280         int count = 0;
2281
2282         list_for_each_entry(sdt_ptr, start, note_list)
2283                 count++;
2284         return count;
2285 }
2286 #endif
2287
2288 void symbol__elf_init(void)
2289 {
2290         elf_version(EV_CURRENT);
2291 }