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