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