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 static int decompress_kmodule(struct dso *dso, const char *name,
 550                               enum dso_binary_type type)
 551 {
 552         int fd;
 553         const char *ext = strrchr(name, '.');
 554         char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
 555
 556         if ((type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
 557              type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP) ||
 558             type != dso->symtab_type)
 559                 return -1;
 560
 561         if (!ext || !is_supported_compression(ext + 1))
 562                 return -1;
 563
 564         fd = mkstemp(tmpbuf);
 565         if (fd < 0)
 566                 return -1;
 567
 568         if (!decompress_to_file(ext + 1, name, fd)) {
 569                 close(fd);
 570                 fd = -1;
 571         }
 572
 573         unlink(tmpbuf);
 574
 575         return fd;
 576 }
 577
 578 bool symsrc__possibly_runtime(struct symsrc *ss)
 579 {
 580         return ss->dynsym || ss->opdsec;
 581 }
 582
 583 bool symsrc__has_symtab(struct symsrc *ss)
 584 {
 585         return ss->symtab != NULL;
 586 }
 587
 588 void symsrc__destroy(struct symsrc *ss)
 589 {
 590         zfree(&ss->name);
 591         elf_end(ss->elf);
 592         close(ss->fd);
 593 }
 594
 595 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 596                  enum dso_binary_type type)
 597 {
 598         int err = -1;
 599         GElf_Ehdr ehdr;
 600         Elf *elf;
 601         int fd;
 602
 603         if (dso__needs_decompress(dso))
 604                 fd = decompress_kmodule(dso, name, type);
 605         else
 606                 fd = open(name, O_RDONLY);
 607
 608         if (fd < 0)
 609                 return -1;
 610
 611         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 612         if (elf == NULL) {
 613                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 614                 goto out_close;
 615         }
 616
 617         if (gelf_getehdr(elf, &ehdr) == NULL) {
 618                 pr_debug("%s: cannot get elf header.\n", __func__);
 619                 goto out_elf_end;
 620         }
 621
 622         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA]))
 623                 goto out_elf_end;
 624
 625         /* Always reject images with a mismatched build-id: */
 626         if (dso->has_build_id) {
 627                 u8 build_id[BUILD_ID_SIZE];
 628
 629                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0)
 630                         goto out_elf_end;
 631
 632                 if (!dso__build_id_equal(dso, build_id))
 633                         goto out_elf_end;
 634         }
 635
 636         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 637
 638         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 639                         NULL);
 640         if (ss->symshdr.sh_type != SHT_SYMTAB)
 641                 ss->symtab = NULL;
 642
 643         ss->dynsym_idx = 0;
 644         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 645                         &ss->dynsym_idx);
 646         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 647                 ss->dynsym = NULL;
 648
 649         ss->opdidx = 0;
 650         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 651                         &ss->opdidx);
 652         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 653                 ss->opdsec = NULL;
 654
 655         if (dso->kernel == DSO_TYPE_USER) {
 656                 GElf_Shdr shdr;
 657                 ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
 658                                 ehdr.e_type == ET_REL ||
 659                                 dso__is_vdso(dso) ||
 660                                 elf_section_by_name(elf, &ehdr, &shdr,
 661                                                      ".gnu.prelink_undo",
 662                                                      NULL) != NULL);
 663         } else {
 664                 ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
 665                                      ehdr.e_type == ET_REL;
 666         }
 667
 668         ss->name   = strdup(name);
 669         if (!ss->name)
 670                 goto out_elf_end;
 671
 672         ss->elf    = elf;
 673         ss->fd     = fd;
 674         ss->ehdr   = ehdr;
 675         ss->type   = type;
 676
 677         return 0;
 678
 679 out_elf_end:
 680         elf_end(elf);
 681 out_close:
 682         close(fd);
 683         return err;
 684 }
 685
 686 /**
 687  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 688  * @kmap: kernel maps and relocation reference symbol
 689  *
 690  * This function returns %true if we are dealing with the kernel maps and the
 691  * relocation reference symbol has not yet been found.  Otherwise %false is
 692  * returned.
 693  */
 694 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 695 {
 696         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 697                !kmap->ref_reloc_sym->unrelocated_addr;
 698 }
 699
 700 /**
 701  * ref_reloc - kernel relocation offset.
 702  * @kmap: kernel maps and relocation reference symbol
 703  *
 704  * This function returns the offset of kernel addresses as determined by using
 705  * the relocation reference symbol i.e. if the kernel has not been relocated
 706  * then the return value is zero.
 707  */
 708 static u64 ref_reloc(struct kmap *kmap)
 709 {
 710         if (kmap && kmap->ref_reloc_sym &&
 711             kmap->ref_reloc_sym->unrelocated_addr)
 712                 return kmap->ref_reloc_sym->addr -
 713                        kmap->ref_reloc_sym->unrelocated_addr;
 714         return 0;
 715 }
 716
 717 static bool want_demangle(bool is_kernel_sym)
 718 {
 719         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 720 }
 721
 722 int dso__load_sym(struct dso *dso, struct map *map,
 723                   struct symsrc *syms_ss, struct symsrc *runtime_ss,
 724                   symbol_filter_t filter, int kmodule)
 725 {
 726         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 727         struct map *curr_map = map;
 728         struct dso *curr_dso = dso;
 729         Elf_Data *symstrs, *secstrs;
 730         uint32_t nr_syms;
 731         int err = -1;
 732         uint32_t idx;
 733         GElf_Ehdr ehdr;
 734         GElf_Shdr shdr;
 735         Elf_Data *syms, *opddata = NULL;
 736         GElf_Sym sym;
 737         Elf_Scn *sec, *sec_strndx;
 738         Elf *elf;
 739         int nr = 0;
 740         bool remap_kernel = false, adjust_kernel_syms = false;
 741
 742         dso->symtab_type = syms_ss->type;
 743         dso->is_64_bit = syms_ss->is_64_bit;
 744         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 745
 746         /*
 747          * Modules may already have symbols from kallsyms, but those symbols
 748          * have the wrong values for the dso maps, so remove them.
 749          */
 750         if (kmodule && syms_ss->symtab)
 751                 symbols__delete(&dso->symbols[map->type]);
 752
 753         if (!syms_ss->symtab) {
 754                 /*
 755                  * If the vmlinux is stripped, fail so we will fall back
 756                  * to using kallsyms. The vmlinux runtime symbols aren't
 757                  * of much use.
 758                  */
 759                 if (dso->kernel)
 760                         goto out_elf_end;
 761
 762                 syms_ss->symtab  = syms_ss->dynsym;
 763                 syms_ss->symshdr = syms_ss->dynshdr;
 764         }
 765
 766         elf = syms_ss->elf;
 767         ehdr = syms_ss->ehdr;
 768         sec = syms_ss->symtab;
 769         shdr = syms_ss->symshdr;
 770
 771         if (runtime_ss->opdsec)
 772                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 773
 774         syms = elf_getdata(sec, NULL);
 775         if (syms == NULL)
 776                 goto out_elf_end;
 777
 778         sec = elf_getscn(elf, shdr.sh_link);
 779         if (sec == NULL)
 780                 goto out_elf_end;
 781
 782         symstrs = elf_getdata(sec, NULL);
 783         if (symstrs == NULL)
 784                 goto out_elf_end;
 785
 786         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
 787         if (sec_strndx == NULL)
 788                 goto out_elf_end;
 789
 790         secstrs = elf_getdata(sec_strndx, NULL);
 791         if (secstrs == NULL)
 792                 goto out_elf_end;
 793
 794         nr_syms = shdr.sh_size / shdr.sh_entsize;
 795
 796         memset(&sym, 0, sizeof(sym));
 797
 798         /*
 799          * The kernel relocation symbol is needed in advance in order to adjust
 800          * kernel maps correctly.
 801          */
 802         if (ref_reloc_sym_not_found(kmap)) {
 803                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 804                         const char *elf_name = elf_sym__name(&sym, symstrs);
 805
 806                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
 807                                 continue;
 808                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
 809                         map->reloc = kmap->ref_reloc_sym->addr -
 810                                      kmap->ref_reloc_sym->unrelocated_addr;
 811                         break;
 812                 }
 813         }
 814
 815         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
 816         /*
 817          * Initial kernel and module mappings do not map to the dso.  For
 818          * function mappings, flag the fixups.
 819          */
 820         if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
 821                 remap_kernel = true;
 822                 adjust_kernel_syms = dso->adjust_symbols;
 823         }
 824         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 825                 struct symbol *f;
 826                 const char *elf_name = elf_sym__name(&sym, symstrs);
 827                 char *demangled = NULL;
 828                 int is_label = elf_sym__is_label(&sym);
 829                 const char *section_name;
 830                 bool used_opd = false;
 831
 832                 if (!is_label && !elf_sym__is_a(&sym, map->type))
 833                         continue;
 834
 835                 /* Reject ARM ELF "mapping symbols": these aren't unique and
 836                  * don't identify functions, so will confuse the profile
 837                  * output: */
 838                 if (ehdr.e_machine == EM_ARM) {
 839                         if (!strcmp(elf_name, "$a") ||
 840                             !strcmp(elf_name, "$d") ||
 841                             !strcmp(elf_name, "$t"))
 842                                 continue;
 843                 }
 844
 845                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
 846                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
 847                         u64 *opd = opddata->d_buf + offset;
 848                         sym.st_value = DSO__SWAP(dso, u64, *opd);
 849                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
 850                                         sym.st_value);
 851                         used_opd = true;
 852                 }
 853                 /*
 854                  * When loading symbols in a data mapping, ABS symbols (which
 855                  * has a value of SHN_ABS in its st_shndx) failed at
 856                  * elf_getscn().  And it marks the loading as a failure so
 857                  * already loaded symbols cannot be fixed up.
 858                  *
 859                  * I'm not sure what should be done. Just ignore them for now.
 860                  * - Namhyung Kim
 861                  */
 862                 if (sym.st_shndx == SHN_ABS)
 863                         continue;
 864
 865                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
 866                 if (!sec)
 867                         goto out_elf_end;
 868
 869                 gelf_getshdr(sec, &shdr);
 870
 871                 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
 872                         continue;
 873
 874                 section_name = elf_sec__name(&shdr, secstrs);
 875
 876                 /* On ARM, symbols for thumb functions have 1 added to
 877                  * the symbol address as a flag - remove it */
 878                 if ((ehdr.e_machine == EM_ARM) &&
 879                     (map->type == MAP__FUNCTION) &&
 880                     (sym.st_value & 1))
 881                         --sym.st_value;
 882
 883                 if (dso->kernel || kmodule) {
 884                         char dso_name[PATH_MAX];
 885
 886                         /* Adjust symbol to map to file offset */
 887                         if (adjust_kernel_syms)
 888                                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 889
 890                         if (strcmp(section_name,
 891                                    (curr_dso->short_name +
 892                                     dso->short_name_len)) == 0)
 893                                 goto new_symbol;
 894
 895                         if (strcmp(section_name, ".text") == 0) {
 896                                 /*
 897                                  * The initial kernel mapping is based on
 898                                  * kallsyms and identity maps.  Overwrite it to
 899                                  * map to the kernel dso.
 900                                  */
 901                                 if (remap_kernel && dso->kernel) {
 902                                         remap_kernel = false;
 903                                         map->start = shdr.sh_addr +
 904                                                      ref_reloc(kmap);
 905                                         map->end = map->start + shdr.sh_size;
 906                                         map->pgoff = shdr.sh_offset;
 907                                         map->map_ip = map__map_ip;
 908                                         map->unmap_ip = map__unmap_ip;
 909                                         /* Ensure maps are correctly ordered */
 910                                         map_groups__remove(kmap->kmaps, map);
 911                                         map_groups__insert(kmap->kmaps, map);
 912                                 }
 913
 914                                 /*
 915                                  * The initial module mapping is based on
 916                                  * /proc/modules mapped to offset zero.
 917                                  * Overwrite it to map to the module dso.
 918                                  */
 919                                 if (remap_kernel && kmodule) {
 920                                         remap_kernel = false;
 921                                         map->pgoff = shdr.sh_offset;
 922                                 }
 923
 924                                 curr_map = map;
 925                                 curr_dso = dso;
 926                                 goto new_symbol;
 927                         }
 928
 929                         if (!kmap)
 930                                 goto new_symbol;
 931
 932                         snprintf(dso_name, sizeof(dso_name),
 933                                  "%s%s", dso->short_name, section_name);
 934
 935                         curr_map = map_groups__find_by_name(kmap->kmaps, map->type, dso_name);
 936                         if (curr_map == NULL) {
 937                                 u64 start = sym.st_value;
 938
 939                                 if (kmodule)
 940                                         start += map->start + shdr.sh_offset;
 941
 942                                 curr_dso = dso__new(dso_name);
 943                                 if (curr_dso == NULL)
 944                                         goto out_elf_end;
 945                                 curr_dso->kernel = dso->kernel;
 946                                 curr_dso->long_name = dso->long_name;
 947                                 curr_dso->long_name_len = dso->long_name_len;
 948                                 curr_map = map__new2(start, curr_dso,
 949                                                      map->type);
 950                                 if (curr_map == NULL) {
 951                                         dso__delete(curr_dso);
 952                                         goto out_elf_end;
 953                                 }
 954                                 if (adjust_kernel_syms) {
 955                                         curr_map->start = shdr.sh_addr +
 956                                                           ref_reloc(kmap);
 957                                         curr_map->end = curr_map->start +
 958                                                         shdr.sh_size;
 959                                         curr_map->pgoff = shdr.sh_offset;
 960                                 } else {
 961                                         curr_map->map_ip = identity__map_ip;
 962                                         curr_map->unmap_ip = identity__map_ip;
 963                                 }
 964                                 curr_dso->symtab_type = dso->symtab_type;
 965                                 map_groups__insert(kmap->kmaps, curr_map);
 966                                 /*
 967                                  * The new DSO should go to the kernel DSOS
 968                                  */
 969                                 dsos__add(&map->groups->machine->kernel_dsos,
 970                                           curr_dso);
 971                                 dso__set_loaded(curr_dso, map->type);
 972                         } else
 973                                 curr_dso = curr_map->dso;
 974
 975                         goto new_symbol;
 976                 }
 977
 978                 if ((used_opd && runtime_ss->adjust_symbols)
 979                                 || (!used_opd && syms_ss->adjust_symbols)) {
 980                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
 981                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
 982                                   (u64)sym.st_value, (u64)shdr.sh_addr,
 983                                   (u64)shdr.sh_offset);
 984                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 985                 }
 986 new_symbol:
 987                 /*
 988                  * We need to figure out if the object was created from C++ sources
 989                  * DWARF DW_compile_unit has this, but we don't always have access
 990                  * to it...
 991                  */
 992                 if (want_demangle(dso->kernel || kmodule)) {
 993                         int demangle_flags = DMGL_NO_OPTS;
 994                         if (verbose)
 995                                 demangle_flags = DMGL_PARAMS | DMGL_ANSI;
 996
 997                         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 998                         if (demangled != NULL)
 999                                 elf_name = demangled;
1000                 }
1001                 f = symbol__new(sym.st_value, sym.st_size,
1002                                 GELF_ST_BIND(sym.st_info), elf_name);
1003                 free(demangled);
1004                 if (!f)
1005                         goto out_elf_end;
1006
1007                 if (filter && filter(curr_map, f))
1008                         symbol__delete(f);
1009                 else {
1010                         symbols__insert(&curr_dso->symbols[curr_map->type], f);
1011                         nr++;
1012                 }
1013         }
1014
1015         /*
1016          * For misannotated, zeroed, ASM function sizes.
1017          */
1018         if (nr > 0) {
1019                 symbols__fixup_duplicate(&dso->symbols[map->type]);
1020                 symbols__fixup_end(&dso->symbols[map->type]);
1021                 if (kmap) {
1022                         /*
1023                          * We need to fixup this here too because we create new
1024                          * maps here, for things like vsyscall sections.
1025                          */
1026                         __map_groups__fixup_end(kmap->kmaps, map->type);
1027                 }
1028         }
1029         err = nr;
1030 out_elf_end:
1031         return err;
1032 }
1033
1034 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1035 {
1036         GElf_Phdr phdr;
1037         size_t i, phdrnum;
1038         int err;
1039         u64 sz;
1040
1041         if (elf_getphdrnum(elf, &phdrnum))
1042                 return -1;
1043
1044         for (i = 0; i < phdrnum; i++) {
1045                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1046                         return -1;
1047                 if (phdr.p_type != PT_LOAD)
1048                         continue;
1049                 if (exe) {
1050                         if (!(phdr.p_flags & PF_X))
1051                                 continue;
1052                 } else {
1053                         if (!(phdr.p_flags & PF_R))
1054                                 continue;
1055                 }
1056                 sz = min(phdr.p_memsz, phdr.p_filesz);
1057                 if (!sz)
1058                         continue;
1059                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1060                 if (err)
1061                         return err;
1062         }
1063         return 0;
1064 }
1065
1066 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1067                     bool *is_64_bit)
1068 {
1069         int err;
1070         Elf *elf;
1071
1072         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1073         if (elf == NULL)
1074                 return -1;
1075
1076         if (is_64_bit)
1077                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1078
1079         err = elf_read_maps(elf, exe, mapfn, data);
1080
1081         elf_end(elf);
1082         return err;
1083 }
1084
1085 enum dso_type dso__type_fd(int fd)
1086 {
1087         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1088         GElf_Ehdr ehdr;
1089         Elf_Kind ek;
1090         Elf *elf;
1091
1092         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1093         if (elf == NULL)
1094                 goto out;
1095
1096         ek = elf_kind(elf);
1097         if (ek != ELF_K_ELF)
1098                 goto out_end;
1099
1100         if (gelf_getclass(elf) == ELFCLASS64) {
1101                 dso_type = DSO__TYPE_64BIT;
1102                 goto out_end;
1103         }
1104
1105         if (gelf_getehdr(elf, &ehdr) == NULL)
1106                 goto out_end;
1107
1108         if (ehdr.e_machine == EM_X86_64)
1109                 dso_type = DSO__TYPE_X32BIT;
1110         else
1111                 dso_type = DSO__TYPE_32BIT;
1112 out_end:
1113         elf_end(elf);
1114 out:
1115         return dso_type;
1116 }
1117
1118 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1119 {
1120         ssize_t r;
1121         size_t n;
1122         int err = -1;
1123         char *buf = malloc(page_size);
1124
1125         if (buf == NULL)
1126                 return -1;
1127
1128         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1129                 goto out;
1130
1131         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1132                 goto out;
1133
1134         while (len) {
1135                 n = page_size;
1136                 if (len < n)
1137                         n = len;
1138                 /* Use read because mmap won't work on proc files */
1139                 r = read(from, buf, n);
1140                 if (r < 0)
1141                         goto out;
1142                 if (!r)
1143                         break;
1144                 n = r;
1145                 r = write(to, buf, n);
1146                 if (r < 0)
1147                         goto out;
1148                 if ((size_t)r != n)
1149                         goto out;
1150                 len -= n;
1151         }
1152
1153         err = 0;
1154 out:
1155         free(buf);
1156         return err;
1157 }
1158
1159 struct kcore {
1160         int fd;
1161         int elfclass;
1162         Elf *elf;
1163         GElf_Ehdr ehdr;
1164 };
1165
1166 static int kcore__open(struct kcore *kcore, const char *filename)
1167 {
1168         GElf_Ehdr *ehdr;
1169
1170         kcore->fd = open(filename, O_RDONLY);
1171         if (kcore->fd == -1)
1172                 return -1;
1173
1174         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1175         if (!kcore->elf)
1176                 goto out_close;
1177
1178         kcore->elfclass = gelf_getclass(kcore->elf);
1179         if (kcore->elfclass == ELFCLASSNONE)
1180                 goto out_end;
1181
1182         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1183         if (!ehdr)
1184                 goto out_end;
1185
1186         return 0;
1187
1188 out_end:
1189         elf_end(kcore->elf);
1190 out_close:
1191         close(kcore->fd);
1192         return -1;
1193 }
1194
1195 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1196                        bool temp)
1197 {
1198         GElf_Ehdr *ehdr;
1199
1200         kcore->elfclass = elfclass;
1201
1202         if (temp)
1203                 kcore->fd = mkstemp(filename);
1204         else
1205                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1206         if (kcore->fd == -1)
1207                 return -1;
1208
1209         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1210         if (!kcore->elf)
1211                 goto out_close;
1212
1213         if (!gelf_newehdr(kcore->elf, elfclass))
1214                 goto out_end;
1215
1216         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1217         if (!ehdr)
1218                 goto out_end;
1219
1220         return 0;
1221
1222 out_end:
1223         elf_end(kcore->elf);
1224 out_close:
1225         close(kcore->fd);
1226         unlink(filename);
1227         return -1;
1228 }
1229
1230 static void kcore__close(struct kcore *kcore)
1231 {
1232         elf_end(kcore->elf);
1233         close(kcore->fd);
1234 }
1235
1236 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1237 {
1238         GElf_Ehdr *ehdr = &to->ehdr;
1239         GElf_Ehdr *kehdr = &from->ehdr;
1240
1241         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1242         ehdr->e_type      = kehdr->e_type;
1243         ehdr->e_machine   = kehdr->e_machine;
1244         ehdr->e_version   = kehdr->e_version;
1245         ehdr->e_entry     = 0;
1246         ehdr->e_shoff     = 0;
1247         ehdr->e_flags     = kehdr->e_flags;
1248         ehdr->e_phnum     = count;
1249         ehdr->e_shentsize = 0;
1250         ehdr->e_shnum     = 0;
1251         ehdr->e_shstrndx  = 0;
1252
1253         if (from->elfclass == ELFCLASS32) {
1254                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1255                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1256                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1257         } else {
1258                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1259                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1260                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1261         }
1262
1263         if (!gelf_update_ehdr(to->elf, ehdr))
1264                 return -1;
1265
1266         if (!gelf_newphdr(to->elf, count))
1267                 return -1;
1268
1269         return 0;
1270 }
1271
1272 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1273                            u64 addr, u64 len)
1274 {
1275         GElf_Phdr gphdr;
1276         GElf_Phdr *phdr;
1277
1278         phdr = gelf_getphdr(kcore->elf, idx, &gphdr);
1279         if (!phdr)
1280                 return -1;
1281
1282         phdr->p_type    = PT_LOAD;
1283         phdr->p_flags   = PF_R | PF_W | PF_X;
1284         phdr->p_offset  = offset;
1285         phdr->p_vaddr   = addr;
1286         phdr->p_paddr   = 0;
1287         phdr->p_filesz  = len;
1288         phdr->p_memsz   = len;
1289         phdr->p_align   = page_size;
1290
1291         if (!gelf_update_phdr(kcore->elf, idx, phdr))
1292                 return -1;
1293
1294         return 0;
1295 }
1296
1297 static off_t kcore__write(struct kcore *kcore)
1298 {
1299         return elf_update(kcore->elf, ELF_C_WRITE);
1300 }
1301
1302 struct phdr_data {
1303         off_t offset;
1304         u64 addr;
1305         u64 len;
1306 };
1307
1308 struct kcore_copy_info {
1309         u64 stext;
1310         u64 etext;
1311         u64 first_symbol;
1312         u64 last_symbol;
1313         u64 first_module;
1314         u64 last_module_symbol;
1315         struct phdr_data kernel_map;
1316         struct phdr_data modules_map;
1317 };
1318
1319 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1320                                         u64 start)
1321 {
1322         struct kcore_copy_info *kci = arg;
1323
1324         if (!symbol_type__is_a(type, MAP__FUNCTION))
1325                 return 0;
1326
1327         if (strchr(name, '[')) {
1328                 if (start > kci->last_module_symbol)
1329                         kci->last_module_symbol = start;
1330                 return 0;
1331         }
1332
1333         if (!kci->first_symbol || start < kci->first_symbol)
1334                 kci->first_symbol = start;
1335
1336         if (!kci->last_symbol || start > kci->last_symbol)
1337                 kci->last_symbol = start;
1338
1339         if (!strcmp(name, "_stext")) {
1340                 kci->stext = start;
1341                 return 0;
1342         }
1343
1344         if (!strcmp(name, "_etext")) {
1345                 kci->etext = start;
1346                 return 0;
1347         }
1348
1349         return 0;
1350 }
1351
1352 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1353                                       const char *dir)
1354 {
1355         char kallsyms_filename[PATH_MAX];
1356
1357         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1358
1359         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1360                 return -1;
1361
1362         if (kallsyms__parse(kallsyms_filename, kci,
1363                             kcore_copy__process_kallsyms) < 0)
1364                 return -1;
1365
1366         return 0;
1367 }
1368
1369 static int kcore_copy__process_modules(void *arg,
1370                                        const char *name __maybe_unused,
1371                                        u64 start)
1372 {
1373         struct kcore_copy_info *kci = arg;
1374
1375         if (!kci->first_module || start < kci->first_module)
1376                 kci->first_module = start;
1377
1378         return 0;
1379 }
1380
1381 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1382                                      const char *dir)
1383 {
1384         char modules_filename[PATH_MAX];
1385
1386         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1387
1388         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1389                 return -1;
1390
1391         if (modules__parse(modules_filename, kci,
1392                            kcore_copy__process_modules) < 0)
1393                 return -1;
1394
1395         return 0;
1396 }
1397
1398 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1399                             u64 s, u64 e)
1400 {
1401         if (p->addr || s < start || s >= end)
1402                 return;
1403
1404         p->addr = s;
1405         p->offset = (s - start) + pgoff;
1406         p->len = e < end ? e - s : end - s;
1407 }
1408
1409 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1410 {
1411         struct kcore_copy_info *kci = data;
1412         u64 end = start + len;
1413
1414         kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1415                         kci->etext);
1416
1417         kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1418                         kci->last_module_symbol);
1419
1420         return 0;
1421 }
1422
1423 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1424 {
1425         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1426                 return -1;
1427
1428         return 0;
1429 }
1430
1431 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1432                                  Elf *elf)
1433 {
1434         if (kcore_copy__parse_kallsyms(kci, dir))
1435                 return -1;
1436
1437         if (kcore_copy__parse_modules(kci, dir))
1438                 return -1;
1439
1440         if (kci->stext)
1441                 kci->stext = round_down(kci->stext, page_size);
1442         else
1443                 kci->stext = round_down(kci->first_symbol, page_size);
1444
1445         if (kci->etext) {
1446                 kci->etext = round_up(kci->etext, page_size);
1447         } else if (kci->last_symbol) {
1448                 kci->etext = round_up(kci->last_symbol, page_size);
1449                 kci->etext += page_size;
1450         }
1451
1452         kci->first_module = round_down(kci->first_module, page_size);
1453
1454         if (kci->last_module_symbol) {
1455                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1456                                                    page_size);
1457                 kci->last_module_symbol += page_size;
1458         }
1459
1460         if (!kci->stext || !kci->etext)
1461                 return -1;
1462
1463         if (kci->first_module && !kci->last_module_symbol)
1464                 return -1;
1465
1466         return kcore_copy__read_maps(kci, elf);
1467 }
1468
1469 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1470                                  const char *name)
1471 {
1472         char from_filename[PATH_MAX];
1473         char to_filename[PATH_MAX];
1474
1475         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1476         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1477
1478         return copyfile_mode(from_filename, to_filename, 0400);
1479 }
1480
1481 static int kcore_copy__unlink(const char *dir, const char *name)
1482 {
1483         char filename[PATH_MAX];
1484
1485         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1486
1487         return unlink(filename);
1488 }
1489
1490 static int kcore_copy__compare_fds(int from, int to)
1491 {
1492         char *buf_from;
1493         char *buf_to;
1494         ssize_t ret;
1495         size_t len;
1496         int err = -1;
1497
1498         buf_from = malloc(page_size);
1499         buf_to = malloc(page_size);
1500         if (!buf_from || !buf_to)
1501                 goto out;
1502
1503         while (1) {
1504                 /* Use read because mmap won't work on proc files */
1505                 ret = read(from, buf_from, page_size);
1506                 if (ret < 0)
1507                         goto out;
1508
1509                 if (!ret)
1510                         break;
1511
1512                 len = ret;
1513
1514                 if (readn(to, buf_to, len) != (int)len)
1515                         goto out;
1516
1517                 if (memcmp(buf_from, buf_to, len))
1518                         goto out;
1519         }
1520
1521         err = 0;
1522 out:
1523         free(buf_to);
1524         free(buf_from);
1525         return err;
1526 }
1527
1528 static int kcore_copy__compare_files(const char *from_filename,
1529                                      const char *to_filename)
1530 {
1531         int from, to, err = -1;
1532
1533         from = open(from_filename, O_RDONLY);
1534         if (from < 0)
1535                 return -1;
1536
1537         to = open(to_filename, O_RDONLY);
1538         if (to < 0)
1539                 goto out_close_from;
1540
1541         err = kcore_copy__compare_fds(from, to);
1542
1543         close(to);
1544 out_close_from:
1545         close(from);
1546         return err;
1547 }
1548
1549 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1550                                     const char *name)
1551 {
1552         char from_filename[PATH_MAX];
1553         char to_filename[PATH_MAX];
1554
1555         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1556         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1557
1558         return kcore_copy__compare_files(from_filename, to_filename);
1559 }
1560
1561 /**
1562  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1563  * @from_dir: from directory
1564  * @to_dir: to directory
1565  *
1566  * This function copies kallsyms, modules and kcore files from one directory to
1567  * another.  kallsyms and modules are copied entirely.  Only code segments are
1568  * copied from kcore.  It is assumed that two segments suffice: one for the
1569  * kernel proper and one for all the modules.  The code segments are determined
1570  * from kallsyms and modules files.  The kernel map starts at _stext or the
1571  * lowest function symbol, and ends at _etext or the highest function symbol.
1572  * The module map starts at the lowest module address and ends at the highest
1573  * module symbol.  Start addresses are rounded down to the nearest page.  End
1574  * addresses are rounded up to the nearest page.  An extra page is added to the
1575  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1576  * symbol too.  Because it contains only code sections, the resulting kcore is
1577  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1578  * is not the same for the kernel map and the modules map.  That happens because
1579  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1580  * kallsyms and modules files are compared with their copies to check that
1581  * modules have not been loaded or unloaded while the copies were taking place.
1582  *
1583  * Return: %0 on success, %-1 on failure.
1584  */
1585 int kcore_copy(const char *from_dir, const char *to_dir)
1586 {
1587         struct kcore kcore;
1588         struct kcore extract;
1589         size_t count = 2;
1590         int idx = 0, err = -1;
1591         off_t offset = page_size, sz, modules_offset = 0;
1592         struct kcore_copy_info kci = { .stext = 0, };
1593         char kcore_filename[PATH_MAX];
1594         char extract_filename[PATH_MAX];
1595
1596         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1597                 return -1;
1598
1599         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1600                 goto out_unlink_kallsyms;
1601
1602         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1603         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1604
1605         if (kcore__open(&kcore, kcore_filename))
1606                 goto out_unlink_modules;
1607
1608         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1609                 goto out_kcore_close;
1610
1611         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1612                 goto out_kcore_close;
1613
1614         if (!kci.modules_map.addr)
1615                 count -= 1;
1616
1617         if (kcore__copy_hdr(&kcore, &extract, count))
1618                 goto out_extract_close;
1619
1620         if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1621                             kci.kernel_map.len))
1622                 goto out_extract_close;
1623
1624         if (kci.modules_map.addr) {
1625                 modules_offset = offset + kci.kernel_map.len;
1626                 if (kcore__add_phdr(&extract, idx, modules_offset,
1627                                     kci.modules_map.addr, kci.modules_map.len))
1628                         goto out_extract_close;
1629         }
1630
1631         sz = kcore__write(&extract);
1632         if (sz < 0 || sz > offset)
1633                 goto out_extract_close;
1634
1635         if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1636                        kci.kernel_map.len))
1637                 goto out_extract_close;
1638
1639         if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1640                                          extract.fd, modules_offset,
1641                                          kci.modules_map.len))
1642                 goto out_extract_close;
1643
1644         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1645                 goto out_extract_close;
1646
1647         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1648                 goto out_extract_close;
1649
1650         err = 0;
1651
1652 out_extract_close:
1653         kcore__close(&extract);
1654         if (err)
1655                 unlink(extract_filename);
1656 out_kcore_close:
1657         kcore__close(&kcore);
1658 out_unlink_modules:
1659         if (err)
1660                 kcore_copy__unlink(to_dir, "modules");
1661 out_unlink_kallsyms:
1662         if (err)
1663                 kcore_copy__unlink(to_dir, "kallsyms");
1664
1665         return err;
1666 }
1667
1668 int kcore_extract__create(struct kcore_extract *kce)
1669 {
1670         struct kcore kcore;
1671         struct kcore extract;
1672         size_t count = 1;
1673         int idx = 0, err = -1;
1674         off_t offset = page_size, sz;
1675
1676         if (kcore__open(&kcore, kce->kcore_filename))
1677                 return -1;
1678
1679         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1680         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1681                 goto out_kcore_close;
1682
1683         if (kcore__copy_hdr(&kcore, &extract, count))
1684                 goto out_extract_close;
1685
1686         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1687                 goto out_extract_close;
1688
1689         sz = kcore__write(&extract);
1690         if (sz < 0 || sz > offset)
1691                 goto out_extract_close;
1692
1693         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1694                 goto out_extract_close;
1695
1696         err = 0;
1697
1698 out_extract_close:
1699         kcore__close(&extract);
1700         if (err)
1701                 unlink(kce->extract_filename);
1702 out_kcore_close:
1703         kcore__close(&kcore);
1704
1705         return err;
1706 }
1707
1708 void kcore_extract__delete(struct kcore_extract *kce)
1709 {
1710         unlink(kce->extract_filename);
1711 }
1712
1713 void symbol__elf_init(void)
1714 {
1715         elf_version(EV_CURRENT);
1716 }