tools/perf/util/symbol-elf.c

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