tools/perf/util/symbol-elf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <errno.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <inttypes.h>
   9
  10 #include "dso.h"
  11 #include "map.h"
  12 #include "maps.h"
  13 #include "symbol.h"
  14 #include "symsrc.h"
  15 #include "demangle-java.h"
  16 #include "demangle-rust.h"
  17 #include "machine.h"
  18 #include "vdso.h"
  19 #include "debug.h"
  20 #include "util/copyfile.h"
  21 #include <linux/ctype.h>
  22 #include <linux/kernel.h>
  23 #include <linux/zalloc.h>
  24 #include <symbol/kallsyms.h>
  25 #include <internal/lib.h>
  26
  27 #ifndef EM_AARCH64
  28 #define EM_AARCH64      183  /* ARM 64 bit */
  29 #endif
  30
  31 #ifndef ELF32_ST_VISIBILITY
  32 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  33 #endif
  34
  35 /* For ELF64 the definitions are the same.  */
  36 #ifndef ELF64_ST_VISIBILITY
  37 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  38 #endif
  39
  40 /* How to extract information held in the st_other field.  */
  41 #ifndef GELF_ST_VISIBILITY
  42 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  43 #endif
  44
  45 typedef Elf64_Nhdr GElf_Nhdr;
  46
  47 #ifndef DMGL_PARAMS
  48 #define DMGL_NO_OPTS     0              /* For readability... */
  49 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  50 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  51 #endif
  52
  53 #ifdef HAVE_LIBBFD_SUPPORT
  54 #define PACKAGE 'perf'
  55 #include <bfd.h>
  56 #else
  57 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  58 extern char *cplus_demangle(const char *, int);
  59
  60 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  61 {
  62         return cplus_demangle(c, i);
  63 }
  64 #else
  65 #ifdef NO_DEMANGLE
  66 static inline char *bfd_demangle(void __maybe_unused *v,
  67                                  const char __maybe_unused *c,
  68                                  int __maybe_unused i)
  69 {
  70         return NULL;
  71 }
  72 #endif
  73 #endif
  74 #endif
  75
  76 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  77 static int elf_getphdrnum(Elf *elf, size_t *dst)
  78 {
  79         GElf_Ehdr gehdr;
  80         GElf_Ehdr *ehdr;
  81
  82         ehdr = gelf_getehdr(elf, &gehdr);
  83         if (!ehdr)
  84                 return -1;
  85
  86         *dst = ehdr->e_phnum;
  87
  88         return 0;
  89 }
  90 #endif
  91
  92 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  93 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  94 {
  95         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  96         return -1;
  97 }
  98 #endif
  99
 100 #ifndef NT_GNU_BUILD_ID
 101 #define NT_GNU_BUILD_ID 3
 102 #endif
 103
 104 /**
 105  * elf_symtab__for_each_symbol - iterate thru all the symbols
 106  *
 107  * @syms: struct elf_symtab instance to iterate
 108  * @idx: uint32_t idx
 109  * @sym: GElf_Sym iterator
 110  */
 111 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 112         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 113              idx < nr_syms; \
 114              idx++, gelf_getsym(syms, idx, &sym))
 115
 116 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 117 {
 118         return GELF_ST_TYPE(sym->st_info);
 119 }
 120
 121 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 122 {
 123         return GELF_ST_VISIBILITY(sym->st_other);
 124 }
 125
 126 #ifndef STT_GNU_IFUNC
 127 #define STT_GNU_IFUNC 10
 128 #endif
 129
 130 static inline int elf_sym__is_function(const GElf_Sym *sym)
 131 {
 132         return (elf_sym__type(sym) == STT_FUNC ||
 133                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 134                sym->st_name != 0 &&
 135                sym->st_shndx != SHN_UNDEF;
 136 }
 137
 138 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 139 {
 140         return elf_sym__type(sym) == STT_OBJECT &&
 141                 sym->st_name != 0 &&
 142                 sym->st_shndx != SHN_UNDEF;
 143 }
 144
 145 static inline int elf_sym__is_label(const GElf_Sym *sym)
 146 {
 147         return elf_sym__type(sym) == STT_NOTYPE &&
 148                 sym->st_name != 0 &&
 149                 sym->st_shndx != SHN_UNDEF &&
 150                 sym->st_shndx != SHN_ABS &&
 151                 elf_sym__visibility(sym) != STV_HIDDEN &&
 152                 elf_sym__visibility(sym) != STV_INTERNAL;
 153 }
 154
 155 static bool elf_sym__filter(GElf_Sym *sym)
 156 {
 157         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 158 }
 159
 160 static inline const char *elf_sym__name(const GElf_Sym *sym,
 161                                         const Elf_Data *symstrs)
 162 {
 163         return symstrs->d_buf + sym->st_name;
 164 }
 165
 166 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 167                                         const Elf_Data *secstrs)
 168 {
 169         return secstrs->d_buf + shdr->sh_name;
 170 }
 171
 172 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 173                                         const Elf_Data *secstrs)
 174 {
 175         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 176 }
 177
 178 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 179                                     const Elf_Data *secstrs)
 180 {
 181         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 182 }
 183
 184 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 185 {
 186         return elf_sec__is_text(shdr, secstrs) ||
 187                elf_sec__is_data(shdr, secstrs);
 188 }
 189
 190 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 191 {
 192         Elf_Scn *sec = NULL;
 193         GElf_Shdr shdr;
 194         size_t cnt = 1;
 195
 196         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 197                 gelf_getshdr(sec, &shdr);
 198
 199                 if ((addr >= shdr.sh_addr) &&
 200                     (addr < (shdr.sh_addr + shdr.sh_size)))
 201                         return cnt;
 202
 203                 ++cnt;
 204         }
 205
 206         return -1;
 207 }
 208
 209 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 210                              GElf_Shdr *shp, const char *name, size_t *idx)
 211 {
 212         Elf_Scn *sec = NULL;
 213         size_t cnt = 1;
 214
 215         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 216         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 217                 return NULL;
 218
 219         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 220                 char *str;
 221
 222                 gelf_getshdr(sec, shp);
 223                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 224                 if (str && !strcmp(name, str)) {
 225                         if (idx)
 226                                 *idx = cnt;
 227                         return sec;
 228                 }
 229                 ++cnt;
 230         }
 231
 232         return NULL;
 233 }
 234
 235 static bool want_demangle(bool is_kernel_sym)
 236 {
 237         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 238 }
 239
 240 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 241 {
 242         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 243         char *demangled = NULL;
 244
 245         /*
 246          * We need to figure out if the object was created from C++ sources
 247          * DWARF DW_compile_unit has this, but we don't always have access
 248          * to it...
 249          */
 250         if (!want_demangle(dso->kernel || kmodule))
 251             return demangled;
 252
 253         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 254         if (demangled == NULL)
 255                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 256         else if (rust_is_mangled(demangled))
 257                 /*
 258                     * Input to Rust demangling is the BFD-demangled
 259                     * name which it Rust-demangles in place.
 260                     */
 261                 rust_demangle_sym(demangled);
 262
 263         return demangled;
 264 }
 265
 266 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 267         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 268              idx < nr_entries; \
 269              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 270
 271 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 272         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 273              idx < nr_entries; \
 274              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 275
 276 /*
 277  * We need to check if we have a .dynsym, so that we can handle the
 278  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 279  * .dynsym or .symtab).
 280  * And always look at the original dso, not at debuginfo packages, that
 281  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 282  */
 283 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 284 {
 285         uint32_t nr_rel_entries, idx;
 286         GElf_Sym sym;
 287         u64 plt_offset, plt_header_size, plt_entry_size;
 288         GElf_Shdr shdr_plt;
 289         struct symbol *f;
 290         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 291         Elf_Data *reldata, *syms, *symstrs;
 292         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 293         size_t dynsym_idx;
 294         GElf_Ehdr ehdr;
 295         char sympltname[1024];
 296         Elf *elf;
 297         int nr = 0, symidx, err = 0;
 298
 299         if (!ss->dynsym)
 300                 return 0;
 301
 302         elf = ss->elf;
 303         ehdr = ss->ehdr;
 304
 305         scn_dynsym = ss->dynsym;
 306         shdr_dynsym = ss->dynshdr;
 307         dynsym_idx = ss->dynsym_idx;
 308
 309         if (scn_dynsym == NULL)
 310                 goto out_elf_end;
 311
 312         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 313                                           ".rela.plt", NULL);
 314         if (scn_plt_rel == NULL) {
 315                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 316                                                   ".rel.plt", NULL);
 317                 if (scn_plt_rel == NULL)
 318                         goto out_elf_end;
 319         }
 320
 321         err = -1;
 322
 323         if (shdr_rel_plt.sh_link != dynsym_idx)
 324                 goto out_elf_end;
 325
 326         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 327                 goto out_elf_end;
 328
 329         /*
 330          * Fetch the relocation section to find the idxes to the GOT
 331          * and the symbols in the .dynsym they refer to.
 332          */
 333         reldata = elf_getdata(scn_plt_rel, NULL);
 334         if (reldata == NULL)
 335                 goto out_elf_end;
 336
 337         syms = elf_getdata(scn_dynsym, NULL);
 338         if (syms == NULL)
 339                 goto out_elf_end;
 340
 341         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 342         if (scn_symstrs == NULL)
 343                 goto out_elf_end;
 344
 345         symstrs = elf_getdata(scn_symstrs, NULL);
 346         if (symstrs == NULL)
 347                 goto out_elf_end;
 348
 349         if (symstrs->d_size == 0)
 350                 goto out_elf_end;
 351
 352         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 353         plt_offset = shdr_plt.sh_offset;
 354         switch (ehdr.e_machine) {
 355                 case EM_ARM:
 356                         plt_header_size = 20;
 357                         plt_entry_size = 12;
 358                         break;
 359
 360                 case EM_AARCH64:
 361                         plt_header_size = 32;
 362                         plt_entry_size = 16;
 363                         break;
 364
 365                 case EM_SPARC:
 366                         plt_header_size = 48;
 367                         plt_entry_size = 12;
 368                         break;
 369
 370                 case EM_SPARCV9:
 371                         plt_header_size = 128;
 372                         plt_entry_size = 32;
 373                         break;
 374
 375                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 376                         plt_header_size = shdr_plt.sh_entsize;
 377                         plt_entry_size = shdr_plt.sh_entsize;
 378                         break;
 379         }
 380         plt_offset += plt_header_size;
 381
 382         if (shdr_rel_plt.sh_type == SHT_RELA) {
 383                 GElf_Rela pos_mem, *pos;
 384
 385                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 386                                            nr_rel_entries) {
 387                         const char *elf_name = NULL;
 388                         char *demangled = NULL;
 389                         symidx = GELF_R_SYM(pos->r_info);
 390                         gelf_getsym(syms, symidx, &sym);
 391
 392                         elf_name = elf_sym__name(&sym, symstrs);
 393                         demangled = demangle_sym(dso, 0, elf_name);
 394                         if (demangled != NULL)
 395                                 elf_name = demangled;
 396                         snprintf(sympltname, sizeof(sympltname),
 397                                  "%s@plt", elf_name);
 398                         free(demangled);
 399
 400                         f = symbol__new(plt_offset, plt_entry_size,
 401                                         STB_GLOBAL, STT_FUNC, sympltname);
 402                         if (!f)
 403                                 goto out_elf_end;
 404
 405                         plt_offset += plt_entry_size;
 406                         symbols__insert(&dso->symbols, f);
 407                         ++nr;
 408                 }
 409         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 410                 GElf_Rel pos_mem, *pos;
 411                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 412                                           nr_rel_entries) {
 413                         const char *elf_name = NULL;
 414                         char *demangled = NULL;
 415                         symidx = GELF_R_SYM(pos->r_info);
 416                         gelf_getsym(syms, symidx, &sym);
 417
 418                         elf_name = elf_sym__name(&sym, symstrs);
 419                         demangled = demangle_sym(dso, 0, elf_name);
 420                         if (demangled != NULL)
 421                                 elf_name = demangled;
 422                         snprintf(sympltname, sizeof(sympltname),
 423                                  "%s@plt", elf_name);
 424                         free(demangled);
 425
 426                         f = symbol__new(plt_offset, plt_entry_size,
 427                                         STB_GLOBAL, STT_FUNC, sympltname);
 428                         if (!f)
 429                                 goto out_elf_end;
 430
 431                         plt_offset += plt_entry_size;
 432                         symbols__insert(&dso->symbols, f);
 433                         ++nr;
 434                 }
 435         }
 436
 437         err = 0;
 438 out_elf_end:
 439         if (err == 0)
 440                 return nr;
 441         pr_debug("%s: problems reading %s PLT info.\n",
 442                  __func__, dso->long_name);
 443         return 0;
 444 }
 445
 446 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 447 {
 448         return demangle_sym(dso, kmodule, elf_name);
 449 }
 450
 451 /*
 452  * Align offset to 4 bytes as needed for note name and descriptor data.
 453  */
 454 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 455
 456 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 457 {
 458         int err = -1;
 459         GElf_Ehdr ehdr;
 460         GElf_Shdr shdr;
 461         Elf_Data *data;
 462         Elf_Scn *sec;
 463         Elf_Kind ek;
 464         void *ptr;
 465
 466         if (size < BUILD_ID_SIZE)
 467                 goto out;
 468
 469         ek = elf_kind(elf);
 470         if (ek != ELF_K_ELF)
 471                 goto out;
 472
 473         if (gelf_getehdr(elf, &ehdr) == NULL) {
 474                 pr_err("%s: cannot get elf header.\n", __func__);
 475                 goto out;
 476         }
 477
 478         /*
 479          * Check following sections for notes:
 480          *   '.note.gnu.build-id'
 481          *   '.notes'
 482          *   '.note' (VDSO specific)
 483          */
 484         do {
 485                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 486                                           ".note.gnu.build-id", NULL);
 487                 if (sec)
 488                         break;
 489
 490                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 491                                           ".notes", NULL);
 492                 if (sec)
 493                         break;
 494
 495                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 496                                           ".note", NULL);
 497                 if (sec)
 498                         break;
 499
 500                 return err;
 501
 502         } while (0);
 503
 504         data = elf_getdata(sec, NULL);
 505         if (data == NULL)
 506                 goto out;
 507
 508         ptr = data->d_buf;
 509         while (ptr < (data->d_buf + data->d_size)) {
 510                 GElf_Nhdr *nhdr = ptr;
 511                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 512                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 513                 const char *name;
 514
 515                 ptr += sizeof(*nhdr);
 516                 name = ptr;
 517                 ptr += namesz;
 518                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 519                     nhdr->n_namesz == sizeof("GNU")) {
 520                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 521                                 size_t sz = min(size, descsz);
 522                                 memcpy(bf, ptr, sz);
 523                                 memset(bf + sz, 0, size - sz);
 524                                 err = descsz;
 525                                 break;
 526                         }
 527                 }
 528                 ptr += descsz;
 529         }
 530
 531 out:
 532         return err;
 533 }
 534
 535 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
 536
 537 static int read_build_id(const char *filename, struct build_id *bid)
 538 {
 539         size_t size = sizeof(bid->data);
 540         int err = -1;
 541         bfd *abfd;
 542
 543         abfd = bfd_openr(filename, NULL);
 544         if (!abfd)
 545                 return -1;
 546
 547         if (!bfd_check_format(abfd, bfd_object)) {
 548                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 549                 goto out_close;
 550         }
 551
 552         if (!abfd->build_id || abfd->build_id->size > size)
 553                 goto out_close;
 554
 555         memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
 556         memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
 557         err = bid->size = abfd->build_id->size;
 558
 559 out_close:
 560         bfd_close(abfd);
 561         return err;
 562 }
 563
 564 #else // HAVE_LIBBFD_BUILDID_SUPPORT
 565
 566 static int read_build_id(const char *filename, struct build_id *bid)
 567 {
 568         size_t size = sizeof(bid->data);
 569         int fd, err = -1;
 570         Elf *elf;
 571
 572         if (size < BUILD_ID_SIZE)
 573                 goto out;
 574
 575         fd = open(filename, O_RDONLY);
 576         if (fd < 0)
 577                 goto out;
 578
 579         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 580         if (elf == NULL) {
 581                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 582                 goto out_close;
 583         }
 584
 585         err = elf_read_build_id(elf, bid->data, size);
 586         if (err > 0)
 587                 bid->size = err;
 588
 589         elf_end(elf);
 590 out_close:
 591         close(fd);
 592 out:
 593         return err;
 594 }
 595
 596 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 597
 598 int filename__read_build_id(const char *filename, struct build_id *bid)
 599 {
 600         struct kmod_path m = { .name = NULL, };
 601         char path[PATH_MAX];
 602         int err;
 603
 604         if (!filename)
 605                 return -EFAULT;
 606
 607         err = kmod_path__parse(&m, filename);
 608         if (err)
 609                 return -1;
 610
 611         if (m.comp) {
 612                 int error = 0, fd;
 613
 614                 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
 615                 if (fd < 0) {
 616                         pr_debug("Failed to decompress (error %d) %s\n",
 617                                  error, filename);
 618                         return -1;
 619                 }
 620                 close(fd);
 621                 filename = path;
 622         }
 623
 624         err = read_build_id(filename, bid);
 625
 626         if (m.comp)
 627                 unlink(filename);
 628         return err;
 629 }
 630
 631 int sysfs__read_build_id(const char *filename, struct build_id *bid)
 632 {
 633         size_t size = sizeof(bid->data);
 634         int fd, err = -1;
 635
 636         fd = open(filename, O_RDONLY);
 637         if (fd < 0)
 638                 goto out;
 639
 640         while (1) {
 641                 char bf[BUFSIZ];
 642                 GElf_Nhdr nhdr;
 643                 size_t namesz, descsz;
 644
 645                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 646                         break;
 647
 648                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 649                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 650                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 651                     nhdr.n_namesz == sizeof("GNU")) {
 652                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 653                                 break;
 654                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 655                                 size_t sz = min(descsz, size);
 656                                 if (read(fd, bid->data, sz) == (ssize_t)sz) {
 657                                         memset(bid->data + sz, 0, size - sz);
 658                                         bid->size = sz;
 659                                         err = 0;
 660                                         break;
 661                                 }
 662                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 663                                 break;
 664                 } else {
 665                         int n = namesz + descsz;
 666
 667                         if (n > (int)sizeof(bf)) {
 668                                 n = sizeof(bf);
 669                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 670                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 671                         }
 672                         if (read(fd, bf, n) != n)
 673                                 break;
 674                 }
 675         }
 676         close(fd);
 677 out:
 678         return err;
 679 }
 680
 681 #ifdef HAVE_LIBBFD_SUPPORT
 682
 683 int filename__read_debuglink(const char *filename, char *debuglink,
 684                              size_t size)
 685 {
 686         int err = -1;
 687         asection *section;
 688         bfd *abfd;
 689
 690         abfd = bfd_openr(filename, NULL);
 691         if (!abfd)
 692                 return -1;
 693
 694         if (!bfd_check_format(abfd, bfd_object)) {
 695                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 696                 goto out_close;
 697         }
 698
 699         section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
 700         if (!section)
 701                 goto out_close;
 702
 703         if (section->size > size)
 704                 goto out_close;
 705
 706         if (!bfd_get_section_contents(abfd, section, debuglink, 0,
 707                                       section->size))
 708                 goto out_close;
 709
 710         err = 0;
 711
 712 out_close:
 713         bfd_close(abfd);
 714         return err;
 715 }
 716
 717 #else
 718
 719 int filename__read_debuglink(const char *filename, char *debuglink,
 720                              size_t size)
 721 {
 722         int fd, err = -1;
 723         Elf *elf;
 724         GElf_Ehdr ehdr;
 725         GElf_Shdr shdr;
 726         Elf_Data *data;
 727         Elf_Scn *sec;
 728         Elf_Kind ek;
 729
 730         fd = open(filename, O_RDONLY);
 731         if (fd < 0)
 732                 goto out;
 733
 734         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 735         if (elf == NULL) {
 736                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 737                 goto out_close;
 738         }
 739
 740         ek = elf_kind(elf);
 741         if (ek != ELF_K_ELF)
 742                 goto out_elf_end;
 743
 744         if (gelf_getehdr(elf, &ehdr) == NULL) {
 745                 pr_err("%s: cannot get elf header.\n", __func__);
 746                 goto out_elf_end;
 747         }
 748
 749         sec = elf_section_by_name(elf, &ehdr, &shdr,
 750                                   ".gnu_debuglink", NULL);
 751         if (sec == NULL)
 752                 goto out_elf_end;
 753
 754         data = elf_getdata(sec, NULL);
 755         if (data == NULL)
 756                 goto out_elf_end;
 757
 758         /* the start of this section is a zero-terminated string */
 759         strncpy(debuglink, data->d_buf, size);
 760
 761         err = 0;
 762
 763 out_elf_end:
 764         elf_end(elf);
 765 out_close:
 766         close(fd);
 767 out:
 768         return err;
 769 }
 770
 771 #endif
 772
 773 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 774 {
 775         static unsigned int const endian = 1;
 776
 777         dso->needs_swap = DSO_SWAP__NO;
 778
 779         switch (eidata) {
 780         case ELFDATA2LSB:
 781                 /* We are big endian, DSO is little endian. */
 782                 if (*(unsigned char const *)&endian != 1)
 783                         dso->needs_swap = DSO_SWAP__YES;
 784                 break;
 785
 786         case ELFDATA2MSB:
 787                 /* We are little endian, DSO is big endian. */
 788                 if (*(unsigned char const *)&endian != 0)
 789                         dso->needs_swap = DSO_SWAP__YES;
 790                 break;
 791
 792         default:
 793                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 794                 return -EINVAL;
 795         }
 796
 797         return 0;
 798 }
 799
 800 bool symsrc__possibly_runtime(struct symsrc *ss)
 801 {
 802         return ss->dynsym || ss->opdsec;
 803 }
 804
 805 bool symsrc__has_symtab(struct symsrc *ss)
 806 {
 807         return ss->symtab != NULL;
 808 }
 809
 810 void symsrc__destroy(struct symsrc *ss)
 811 {
 812         zfree(&ss->name);
 813         elf_end(ss->elf);
 814         close(ss->fd);
 815 }
 816
 817 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 818 {
 819         /*
 820          * Usually vmlinux is an ELF file with type ET_EXEC for most
 821          * architectures; except Arm64 kernel is linked with option
 822          * '-share', so need to check type ET_DYN.
 823          */
 824         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
 825                ehdr.e_type == ET_DYN;
 826 }
 827
 828 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 829                  enum dso_binary_type type)
 830 {
 831         GElf_Ehdr ehdr;
 832         Elf *elf;
 833         int fd;
 834
 835         if (dso__needs_decompress(dso)) {
 836                 fd = dso__decompress_kmodule_fd(dso, name);
 837                 if (fd < 0)
 838                         return -1;
 839
 840                 type = dso->symtab_type;
 841         } else {
 842                 fd = open(name, O_RDONLY);
 843                 if (fd < 0) {
 844                         dso->load_errno = errno;
 845                         return -1;
 846                 }
 847         }
 848
 849         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 850         if (elf == NULL) {
 851                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 852                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 853                 goto out_close;
 854         }
 855
 856         if (gelf_getehdr(elf, &ehdr) == NULL) {
 857                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 858                 pr_debug("%s: cannot get elf header.\n", __func__);
 859                 goto out_elf_end;
 860         }
 861
 862         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 863                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 864                 goto out_elf_end;
 865         }
 866
 867         /* Always reject images with a mismatched build-id: */
 868         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 869                 u8 build_id[BUILD_ID_SIZE];
 870                 struct build_id bid;
 871                 int size;
 872
 873                 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
 874                 if (size <= 0) {
 875                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 876                         goto out_elf_end;
 877                 }
 878
 879                 build_id__init(&bid, build_id, size);
 880                 if (!dso__build_id_equal(dso, &bid)) {
 881                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 882                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 883                         goto out_elf_end;
 884                 }
 885         }
 886
 887         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 888
 889         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 890                         NULL);
 891         if (ss->symshdr.sh_type != SHT_SYMTAB)
 892                 ss->symtab = NULL;
 893
 894         ss->dynsym_idx = 0;
 895         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 896                         &ss->dynsym_idx);
 897         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 898                 ss->dynsym = NULL;
 899
 900         ss->opdidx = 0;
 901         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 902                         &ss->opdidx);
 903         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 904                 ss->opdsec = NULL;
 905
 906         if (dso->kernel == DSO_SPACE__USER)
 907                 ss->adjust_symbols = true;
 908         else
 909                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 910
 911         ss->name   = strdup(name);
 912         if (!ss->name) {
 913                 dso->load_errno = errno;
 914                 goto out_elf_end;
 915         }
 916
 917         ss->elf    = elf;
 918         ss->fd     = fd;
 919         ss->ehdr   = ehdr;
 920         ss->type   = type;
 921
 922         return 0;
 923
 924 out_elf_end:
 925         elf_end(elf);
 926 out_close:
 927         close(fd);
 928         return -1;
 929 }
 930
 931 /**
 932  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 933  * @kmap: kernel maps and relocation reference symbol
 934  *
 935  * This function returns %true if we are dealing with the kernel maps and the
 936  * relocation reference symbol has not yet been found.  Otherwise %false is
 937  * returned.
 938  */
 939 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 940 {
 941         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 942                !kmap->ref_reloc_sym->unrelocated_addr;
 943 }
 944
 945 /**
 946  * ref_reloc - kernel relocation offset.
 947  * @kmap: kernel maps and relocation reference symbol
 948  *
 949  * This function returns the offset of kernel addresses as determined by using
 950  * the relocation reference symbol i.e. if the kernel has not been relocated
 951  * then the return value is zero.
 952  */
 953 static u64 ref_reloc(struct kmap *kmap)
 954 {
 955         if (kmap && kmap->ref_reloc_sym &&
 956             kmap->ref_reloc_sym->unrelocated_addr)
 957                 return kmap->ref_reloc_sym->addr -
 958                        kmap->ref_reloc_sym->unrelocated_addr;
 959         return 0;
 960 }
 961
 962 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 963                 GElf_Sym *sym __maybe_unused) { }
 964
 965 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 966                                       GElf_Sym *sym, GElf_Shdr *shdr,
 967                                       struct maps *kmaps, struct kmap *kmap,
 968                                       struct dso **curr_dsop, struct map **curr_mapp,
 969                                       const char *section_name,
 970                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 971 {
 972         struct dso *curr_dso = *curr_dsop;
 973         struct map *curr_map;
 974         char dso_name[PATH_MAX];
 975
 976         /* Adjust symbol to map to file offset */
 977         if (adjust_kernel_syms)
 978                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 979
 980         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 981                 return 0;
 982
 983         if (strcmp(section_name, ".text") == 0) {
 984                 /*
 985                  * The initial kernel mapping is based on
 986                  * kallsyms and identity maps.  Overwrite it to
 987                  * map to the kernel dso.
 988                  */
 989                 if (*remap_kernel && dso->kernel && !kmodule) {
 990                         *remap_kernel = false;
 991                         map->start = shdr->sh_addr + ref_reloc(kmap);
 992                         map->end = map->start + shdr->sh_size;
 993                         map->pgoff = shdr->sh_offset;
 994                         map->map_ip = map__map_ip;
 995                         map->unmap_ip = map__unmap_ip;
 996                         /* Ensure maps are correctly ordered */
 997                         if (kmaps) {
 998                                 map__get(map);
 999                                 maps__remove(kmaps, map);
1000                                 maps__insert(kmaps, map);
1001                                 map__put(map);
1002                         }
1003                 }
1004
1005                 /*
1006                  * The initial module mapping is based on
1007                  * /proc/modules mapped to offset zero.
1008                  * Overwrite it to map to the module dso.
1009                  */
1010                 if (*remap_kernel && kmodule) {
1011                         *remap_kernel = false;
1012                         map->pgoff = shdr->sh_offset;
1013                 }
1014
1015                 *curr_mapp = map;
1016                 *curr_dsop = dso;
1017                 return 0;
1018         }
1019
1020         if (!kmap)
1021                 return 0;
1022
1023         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1024
1025         curr_map = maps__find_by_name(kmaps, dso_name);
1026         if (curr_map == NULL) {
1027                 u64 start = sym->st_value;
1028
1029                 if (kmodule)
1030                         start += map->start + shdr->sh_offset;
1031
1032                 curr_dso = dso__new(dso_name);
1033                 if (curr_dso == NULL)
1034                         return -1;
1035                 curr_dso->kernel = dso->kernel;
1036                 curr_dso->long_name = dso->long_name;
1037                 curr_dso->long_name_len = dso->long_name_len;
1038                 curr_map = map__new2(start, curr_dso);
1039                 dso__put(curr_dso);
1040                 if (curr_map == NULL)
1041                         return -1;
1042
1043                 if (curr_dso->kernel)
1044                         map__kmap(curr_map)->kmaps = kmaps;
1045
1046                 if (adjust_kernel_syms) {
1047                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
1048                         curr_map->end    = curr_map->start + shdr->sh_size;
1049                         curr_map->pgoff  = shdr->sh_offset;
1050                 } else {
1051                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1052                 }
1053                 curr_dso->symtab_type = dso->symtab_type;
1054                 maps__insert(kmaps, curr_map);
1055                 /*
1056                  * Add it before we drop the referece to curr_map, i.e. while
1057                  * we still are sure to have a reference to this DSO via
1058                  * *curr_map->dso.
1059                  */
1060                 dsos__add(&kmaps->machine->dsos, curr_dso);
1061                 /* kmaps already got it */
1062                 map__put(curr_map);
1063                 dso__set_loaded(curr_dso);
1064                 *curr_mapp = curr_map;
1065                 *curr_dsop = curr_dso;
1066         } else
1067                 *curr_dsop = curr_map->dso;
1068
1069         return 0;
1070 }
1071
1072 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1073                   struct symsrc *runtime_ss, int kmodule)
1074 {
1075         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1076         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1077         struct map *curr_map = map;
1078         struct dso *curr_dso = dso;
1079         Elf_Data *symstrs, *secstrs;
1080         uint32_t nr_syms;
1081         int err = -1;
1082         uint32_t idx;
1083         GElf_Ehdr ehdr;
1084         GElf_Shdr shdr;
1085         GElf_Shdr tshdr;
1086         Elf_Data *syms, *opddata = NULL;
1087         GElf_Sym sym;
1088         Elf_Scn *sec, *sec_strndx;
1089         Elf *elf;
1090         int nr = 0;
1091         bool remap_kernel = false, adjust_kernel_syms = false;
1092
1093         if (kmap && !kmaps)
1094                 return -1;
1095
1096         dso->symtab_type = syms_ss->type;
1097         dso->is_64_bit = syms_ss->is_64_bit;
1098         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1099
1100         /*
1101          * Modules may already have symbols from kallsyms, but those symbols
1102          * have the wrong values for the dso maps, so remove them.
1103          */
1104         if (kmodule && syms_ss->symtab)
1105                 symbols__delete(&dso->symbols);
1106
1107         if (!syms_ss->symtab) {
1108                 /*
1109                  * If the vmlinux is stripped, fail so we will fall back
1110                  * to using kallsyms. The vmlinux runtime symbols aren't
1111                  * of much use.
1112                  */
1113                 if (dso->kernel)
1114                         goto out_elf_end;
1115
1116                 syms_ss->symtab  = syms_ss->dynsym;
1117                 syms_ss->symshdr = syms_ss->dynshdr;
1118         }
1119
1120         elf = syms_ss->elf;
1121         ehdr = syms_ss->ehdr;
1122         sec = syms_ss->symtab;
1123         shdr = syms_ss->symshdr;
1124
1125         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1126                                 ".text", NULL))
1127                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1128
1129         if (runtime_ss->opdsec)
1130                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1131
1132         syms = elf_getdata(sec, NULL);
1133         if (syms == NULL)
1134                 goto out_elf_end;
1135
1136         sec = elf_getscn(elf, shdr.sh_link);
1137         if (sec == NULL)
1138                 goto out_elf_end;
1139
1140         symstrs = elf_getdata(sec, NULL);
1141         if (symstrs == NULL)
1142                 goto out_elf_end;
1143
1144         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1145         if (sec_strndx == NULL)
1146                 goto out_elf_end;
1147
1148         secstrs = elf_getdata(sec_strndx, NULL);
1149         if (secstrs == NULL)
1150                 goto out_elf_end;
1151
1152         nr_syms = shdr.sh_size / shdr.sh_entsize;
1153
1154         memset(&sym, 0, sizeof(sym));
1155
1156         /*
1157          * The kernel relocation symbol is needed in advance in order to adjust
1158          * kernel maps correctly.
1159          */
1160         if (ref_reloc_sym_not_found(kmap)) {
1161                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1162                         const char *elf_name = elf_sym__name(&sym, symstrs);
1163
1164                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1165                                 continue;
1166                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1167                         map->reloc = kmap->ref_reloc_sym->addr -
1168                                      kmap->ref_reloc_sym->unrelocated_addr;
1169                         break;
1170                 }
1171         }
1172
1173         /*
1174          * Handle any relocation of vdso necessary because older kernels
1175          * attempted to prelink vdso to its virtual address.
1176          */
1177         if (dso__is_vdso(dso))
1178                 map->reloc = map->start - dso->text_offset;
1179
1180         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1181         /*
1182          * Initial kernel and module mappings do not map to the dso.
1183          * Flag the fixups.
1184          */
1185         if (dso->kernel) {
1186                 remap_kernel = true;
1187                 adjust_kernel_syms = dso->adjust_symbols;
1188         }
1189         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1190                 struct symbol *f;
1191                 const char *elf_name = elf_sym__name(&sym, symstrs);
1192                 char *demangled = NULL;
1193                 int is_label = elf_sym__is_label(&sym);
1194                 const char *section_name;
1195                 bool used_opd = false;
1196
1197                 if (!is_label && !elf_sym__filter(&sym))
1198                         continue;
1199
1200                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1201                  * don't identify functions, so will confuse the profile
1202                  * output: */
1203                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1204                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1205                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1206                                 continue;
1207                 }
1208
1209                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1210                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1211                         u64 *opd = opddata->d_buf + offset;
1212                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1213                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1214                                         sym.st_value);
1215                         used_opd = true;
1216                 }
1217                 /*
1218                  * When loading symbols in a data mapping, ABS symbols (which
1219                  * has a value of SHN_ABS in its st_shndx) failed at
1220                  * elf_getscn().  And it marks the loading as a failure so
1221                  * already loaded symbols cannot be fixed up.
1222                  *
1223                  * I'm not sure what should be done. Just ignore them for now.
1224                  * - Namhyung Kim
1225                  */
1226                 if (sym.st_shndx == SHN_ABS)
1227                         continue;
1228
1229                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1230                 if (!sec)
1231                         goto out_elf_end;
1232
1233                 gelf_getshdr(sec, &shdr);
1234
1235                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1236                         continue;
1237
1238                 section_name = elf_sec__name(&shdr, secstrs);
1239
1240                 /* On ARM, symbols for thumb functions have 1 added to
1241                  * the symbol address as a flag - remove it */
1242                 if ((ehdr.e_machine == EM_ARM) &&
1243                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1244                     (sym.st_value & 1))
1245                         --sym.st_value;
1246
1247                 if (dso->kernel) {
1248                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1249                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1250                                 goto out_elf_end;
1251                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1252                            (!used_opd && syms_ss->adjust_symbols)) {
1253                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1254                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1255                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1256                                   (u64)shdr.sh_offset);
1257                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1258                 }
1259
1260                 demangled = demangle_sym(dso, kmodule, elf_name);
1261                 if (demangled != NULL)
1262                         elf_name = demangled;
1263
1264                 f = symbol__new(sym.st_value, sym.st_size,
1265                                 GELF_ST_BIND(sym.st_info),
1266                                 GELF_ST_TYPE(sym.st_info), elf_name);
1267                 free(demangled);
1268                 if (!f)
1269                         goto out_elf_end;
1270
1271                 arch__sym_update(f, &sym);
1272
1273                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1274                 nr++;
1275         }
1276
1277         /*
1278          * For misannotated, zeroed, ASM function sizes.
1279          */
1280         if (nr > 0) {
1281                 symbols__fixup_end(&dso->symbols);
1282                 symbols__fixup_duplicate(&dso->symbols);
1283                 if (kmap) {
1284                         /*
1285                          * We need to fixup this here too because we create new
1286                          * maps here, for things like vsyscall sections.
1287                          */
1288                         maps__fixup_end(kmaps);
1289                 }
1290         }
1291         err = nr;
1292 out_elf_end:
1293         return err;
1294 }
1295
1296 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1297 {
1298         GElf_Phdr phdr;
1299         size_t i, phdrnum;
1300         int err;
1301         u64 sz;
1302
1303         if (elf_getphdrnum(elf, &phdrnum))
1304                 return -1;
1305
1306         for (i = 0; i < phdrnum; i++) {
1307                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1308                         return -1;
1309                 if (phdr.p_type != PT_LOAD)
1310                         continue;
1311                 if (exe) {
1312                         if (!(phdr.p_flags & PF_X))
1313                                 continue;
1314                 } else {
1315                         if (!(phdr.p_flags & PF_R))
1316                                 continue;
1317                 }
1318                 sz = min(phdr.p_memsz, phdr.p_filesz);
1319                 if (!sz)
1320                         continue;
1321                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1322                 if (err)
1323                         return err;
1324         }
1325         return 0;
1326 }
1327
1328 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1329                     bool *is_64_bit)
1330 {
1331         int err;
1332         Elf *elf;
1333
1334         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1335         if (elf == NULL)
1336                 return -1;
1337
1338         if (is_64_bit)
1339                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1340
1341         err = elf_read_maps(elf, exe, mapfn, data);
1342
1343         elf_end(elf);
1344         return err;
1345 }
1346
1347 enum dso_type dso__type_fd(int fd)
1348 {
1349         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1350         GElf_Ehdr ehdr;
1351         Elf_Kind ek;
1352         Elf *elf;
1353
1354         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1355         if (elf == NULL)
1356                 goto out;
1357
1358         ek = elf_kind(elf);
1359         if (ek != ELF_K_ELF)
1360                 goto out_end;
1361
1362         if (gelf_getclass(elf) == ELFCLASS64) {
1363                 dso_type = DSO__TYPE_64BIT;
1364                 goto out_end;
1365         }
1366
1367         if (gelf_getehdr(elf, &ehdr) == NULL)
1368                 goto out_end;
1369
1370         if (ehdr.e_machine == EM_X86_64)
1371                 dso_type = DSO__TYPE_X32BIT;
1372         else
1373                 dso_type = DSO__TYPE_32BIT;
1374 out_end:
1375         elf_end(elf);
1376 out:
1377         return dso_type;
1378 }
1379
1380 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1381 {
1382         ssize_t r;
1383         size_t n;
1384         int err = -1;
1385         char *buf = malloc(page_size);
1386
1387         if (buf == NULL)
1388                 return -1;
1389
1390         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1391                 goto out;
1392
1393         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1394                 goto out;
1395
1396         while (len) {
1397                 n = page_size;
1398                 if (len < n)
1399                         n = len;
1400                 /* Use read because mmap won't work on proc files */
1401                 r = read(from, buf, n);
1402                 if (r < 0)
1403                         goto out;
1404                 if (!r)
1405                         break;
1406                 n = r;
1407                 r = write(to, buf, n);
1408                 if (r < 0)
1409                         goto out;
1410                 if ((size_t)r != n)
1411                         goto out;
1412                 len -= n;
1413         }
1414
1415         err = 0;
1416 out:
1417         free(buf);
1418         return err;
1419 }
1420
1421 struct kcore {
1422         int fd;
1423         int elfclass;
1424         Elf *elf;
1425         GElf_Ehdr ehdr;
1426 };
1427
1428 static int kcore__open(struct kcore *kcore, const char *filename)
1429 {
1430         GElf_Ehdr *ehdr;
1431
1432         kcore->fd = open(filename, O_RDONLY);
1433         if (kcore->fd == -1)
1434                 return -1;
1435
1436         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1437         if (!kcore->elf)
1438                 goto out_close;
1439
1440         kcore->elfclass = gelf_getclass(kcore->elf);
1441         if (kcore->elfclass == ELFCLASSNONE)
1442                 goto out_end;
1443
1444         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1445         if (!ehdr)
1446                 goto out_end;
1447
1448         return 0;
1449
1450 out_end:
1451         elf_end(kcore->elf);
1452 out_close:
1453         close(kcore->fd);
1454         return -1;
1455 }
1456
1457 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1458                        bool temp)
1459 {
1460         kcore->elfclass = elfclass;
1461
1462         if (temp)
1463                 kcore->fd = mkstemp(filename);
1464         else
1465                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1466         if (kcore->fd == -1)
1467                 return -1;
1468
1469         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1470         if (!kcore->elf)
1471                 goto out_close;
1472
1473         if (!gelf_newehdr(kcore->elf, elfclass))
1474                 goto out_end;
1475
1476         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1477
1478         return 0;
1479
1480 out_end:
1481         elf_end(kcore->elf);
1482 out_close:
1483         close(kcore->fd);
1484         unlink(filename);
1485         return -1;
1486 }
1487
1488 static void kcore__close(struct kcore *kcore)
1489 {
1490         elf_end(kcore->elf);
1491         close(kcore->fd);
1492 }
1493
1494 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1495 {
1496         GElf_Ehdr *ehdr = &to->ehdr;
1497         GElf_Ehdr *kehdr = &from->ehdr;
1498
1499         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1500         ehdr->e_type      = kehdr->e_type;
1501         ehdr->e_machine   = kehdr->e_machine;
1502         ehdr->e_version   = kehdr->e_version;
1503         ehdr->e_entry     = 0;
1504         ehdr->e_shoff     = 0;
1505         ehdr->e_flags     = kehdr->e_flags;
1506         ehdr->e_phnum     = count;
1507         ehdr->e_shentsize = 0;
1508         ehdr->e_shnum     = 0;
1509         ehdr->e_shstrndx  = 0;
1510
1511         if (from->elfclass == ELFCLASS32) {
1512                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1513                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1514                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1515         } else {
1516                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1517                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1518                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1519         }
1520
1521         if (!gelf_update_ehdr(to->elf, ehdr))
1522                 return -1;
1523
1524         if (!gelf_newphdr(to->elf, count))
1525                 return -1;
1526
1527         return 0;
1528 }
1529
1530 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1531                            u64 addr, u64 len)
1532 {
1533         GElf_Phdr phdr = {
1534                 .p_type         = PT_LOAD,
1535                 .p_flags        = PF_R | PF_W | PF_X,
1536                 .p_offset       = offset,
1537                 .p_vaddr        = addr,
1538                 .p_paddr        = 0,
1539                 .p_filesz       = len,
1540                 .p_memsz        = len,
1541                 .p_align        = page_size,
1542         };
1543
1544         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1545                 return -1;
1546
1547         return 0;
1548 }
1549
1550 static off_t kcore__write(struct kcore *kcore)
1551 {
1552         return elf_update(kcore->elf, ELF_C_WRITE);
1553 }
1554
1555 struct phdr_data {
1556         off_t offset;
1557         off_t rel;
1558         u64 addr;
1559         u64 len;
1560         struct list_head node;
1561         struct phdr_data *remaps;
1562 };
1563
1564 struct sym_data {
1565         u64 addr;
1566         struct list_head node;
1567 };
1568
1569 struct kcore_copy_info {
1570         u64 stext;
1571         u64 etext;
1572         u64 first_symbol;
1573         u64 last_symbol;
1574         u64 first_module;
1575         u64 first_module_symbol;
1576         u64 last_module_symbol;
1577         size_t phnum;
1578         struct list_head phdrs;
1579         struct list_head syms;
1580 };
1581
1582 #define kcore_copy__for_each_phdr(k, p) \
1583         list_for_each_entry((p), &(k)->phdrs, node)
1584
1585 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1586 {
1587         struct phdr_data *p = zalloc(sizeof(*p));
1588
1589         if (p) {
1590                 p->addr   = addr;
1591                 p->len    = len;
1592                 p->offset = offset;
1593         }
1594
1595         return p;
1596 }
1597
1598 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1599                                                  u64 addr, u64 len,
1600                                                  off_t offset)
1601 {
1602         struct phdr_data *p = phdr_data__new(addr, len, offset);
1603
1604         if (p)
1605                 list_add_tail(&p->node, &kci->phdrs);
1606
1607         return p;
1608 }
1609
1610 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1611 {
1612         struct phdr_data *p, *tmp;
1613
1614         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1615                 list_del_init(&p->node);
1616                 free(p);
1617         }
1618 }
1619
1620 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1621                                             u64 addr)
1622 {
1623         struct sym_data *s = zalloc(sizeof(*s));
1624
1625         if (s) {
1626                 s->addr = addr;
1627                 list_add_tail(&s->node, &kci->syms);
1628         }
1629
1630         return s;
1631 }
1632
1633 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1634 {
1635         struct sym_data *s, *tmp;
1636
1637         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1638                 list_del_init(&s->node);
1639                 free(s);
1640         }
1641 }
1642
1643 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1644                                         u64 start)
1645 {
1646         struct kcore_copy_info *kci = arg;
1647
1648         if (!kallsyms__is_function(type))
1649                 return 0;
1650
1651         if (strchr(name, '[')) {
1652                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1653                         kci->first_module_symbol = start;
1654                 if (start > kci->last_module_symbol)
1655                         kci->last_module_symbol = start;
1656                 return 0;
1657         }
1658
1659         if (!kci->first_symbol || start < kci->first_symbol)
1660                 kci->first_symbol = start;
1661
1662         if (!kci->last_symbol || start > kci->last_symbol)
1663                 kci->last_symbol = start;
1664
1665         if (!strcmp(name, "_stext")) {
1666                 kci->stext = start;
1667                 return 0;
1668         }
1669
1670         if (!strcmp(name, "_etext")) {
1671                 kci->etext = start;
1672                 return 0;
1673         }
1674
1675         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1676                 return -1;
1677
1678         return 0;
1679 }
1680
1681 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1682                                       const char *dir)
1683 {
1684         char kallsyms_filename[PATH_MAX];
1685
1686         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1687
1688         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1689                 return -1;
1690
1691         if (kallsyms__parse(kallsyms_filename, kci,
1692                             kcore_copy__process_kallsyms) < 0)
1693                 return -1;
1694
1695         return 0;
1696 }
1697
1698 static int kcore_copy__process_modules(void *arg,
1699                                        const char *name __maybe_unused,
1700                                        u64 start, u64 size __maybe_unused)
1701 {
1702         struct kcore_copy_info *kci = arg;
1703
1704         if (!kci->first_module || start < kci->first_module)
1705                 kci->first_module = start;
1706
1707         return 0;
1708 }
1709
1710 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1711                                      const char *dir)
1712 {
1713         char modules_filename[PATH_MAX];
1714
1715         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1716
1717         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1718                 return -1;
1719
1720         if (modules__parse(modules_filename, kci,
1721                            kcore_copy__process_modules) < 0)
1722                 return -1;
1723
1724         return 0;
1725 }
1726
1727 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1728                            u64 pgoff, u64 s, u64 e)
1729 {
1730         u64 len, offset;
1731
1732         if (s < start || s >= end)
1733                 return 0;
1734
1735         offset = (s - start) + pgoff;
1736         len = e < end ? e - s : end - s;
1737
1738         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1739 }
1740
1741 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1742 {
1743         struct kcore_copy_info *kci = data;
1744         u64 end = start + len;
1745         struct sym_data *sdat;
1746
1747         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1748                 return -1;
1749
1750         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1751                             kci->last_module_symbol))
1752                 return -1;
1753
1754         list_for_each_entry(sdat, &kci->syms, node) {
1755                 u64 s = round_down(sdat->addr, page_size);
1756
1757                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1758                         return -1;
1759         }
1760
1761         return 0;
1762 }
1763
1764 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1765 {
1766         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1767                 return -1;
1768
1769         return 0;
1770 }
1771
1772 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1773 {
1774         struct phdr_data *p, *k = NULL;
1775         u64 kend;
1776
1777         if (!kci->stext)
1778                 return;
1779
1780         /* Find phdr that corresponds to the kernel map (contains stext) */
1781         kcore_copy__for_each_phdr(kci, p) {
1782                 u64 pend = p->addr + p->len - 1;
1783
1784                 if (p->addr <= kci->stext && pend >= kci->stext) {
1785                         k = p;
1786                         break;
1787                 }
1788         }
1789
1790         if (!k)
1791                 return;
1792
1793         kend = k->offset + k->len;
1794
1795         /* Find phdrs that remap the kernel */
1796         kcore_copy__for_each_phdr(kci, p) {
1797                 u64 pend = p->offset + p->len;
1798
1799                 if (p == k)
1800                         continue;
1801
1802                 if (p->offset >= k->offset && pend <= kend)
1803                         p->remaps = k;
1804         }
1805 }
1806
1807 static void kcore_copy__layout(struct kcore_copy_info *kci)
1808 {
1809         struct phdr_data *p;
1810         off_t rel = 0;
1811
1812         kcore_copy__find_remaps(kci);
1813
1814         kcore_copy__for_each_phdr(kci, p) {
1815                 if (!p->remaps) {
1816                         p->rel = rel;
1817                         rel += p->len;
1818                 }
1819                 kci->phnum += 1;
1820         }
1821
1822         kcore_copy__for_each_phdr(kci, p) {
1823                 struct phdr_data *k = p->remaps;
1824
1825                 if (k)
1826                         p->rel = p->offset - k->offset + k->rel;
1827         }
1828 }
1829
1830 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1831                                  Elf *elf)
1832 {
1833         if (kcore_copy__parse_kallsyms(kci, dir))
1834                 return -1;
1835
1836         if (kcore_copy__parse_modules(kci, dir))
1837                 return -1;
1838
1839         if (kci->stext)
1840                 kci->stext = round_down(kci->stext, page_size);
1841         else
1842                 kci->stext = round_down(kci->first_symbol, page_size);
1843
1844         if (kci->etext) {
1845                 kci->etext = round_up(kci->etext, page_size);
1846         } else if (kci->last_symbol) {
1847                 kci->etext = round_up(kci->last_symbol, page_size);
1848                 kci->etext += page_size;
1849         }
1850
1851         if (kci->first_module_symbol &&
1852             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1853                 kci->first_module = kci->first_module_symbol;
1854
1855         kci->first_module = round_down(kci->first_module, page_size);
1856
1857         if (kci->last_module_symbol) {
1858                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1859                                                    page_size);
1860                 kci->last_module_symbol += page_size;
1861         }
1862
1863         if (!kci->stext || !kci->etext)
1864                 return -1;
1865
1866         if (kci->first_module && !kci->last_module_symbol)
1867                 return -1;
1868
1869         if (kcore_copy__read_maps(kci, elf))
1870                 return -1;
1871
1872         kcore_copy__layout(kci);
1873
1874         return 0;
1875 }
1876
1877 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1878                                  const char *name)
1879 {
1880         char from_filename[PATH_MAX];
1881         char to_filename[PATH_MAX];
1882
1883         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1884         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1885
1886         return copyfile_mode(from_filename, to_filename, 0400);
1887 }
1888
1889 static int kcore_copy__unlink(const char *dir, const char *name)
1890 {
1891         char filename[PATH_MAX];
1892
1893         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1894
1895         return unlink(filename);
1896 }
1897
1898 static int kcore_copy__compare_fds(int from, int to)
1899 {
1900         char *buf_from;
1901         char *buf_to;
1902         ssize_t ret;
1903         size_t len;
1904         int err = -1;
1905
1906         buf_from = malloc(page_size);
1907         buf_to = malloc(page_size);
1908         if (!buf_from || !buf_to)
1909                 goto out;
1910
1911         while (1) {
1912                 /* Use read because mmap won't work on proc files */
1913                 ret = read(from, buf_from, page_size);
1914                 if (ret < 0)
1915                         goto out;
1916
1917                 if (!ret)
1918                         break;
1919
1920                 len = ret;
1921
1922                 if (readn(to, buf_to, len) != (int)len)
1923                         goto out;
1924
1925                 if (memcmp(buf_from, buf_to, len))
1926                         goto out;
1927         }
1928
1929         err = 0;
1930 out:
1931         free(buf_to);
1932         free(buf_from);
1933         return err;
1934 }
1935
1936 static int kcore_copy__compare_files(const char *from_filename,
1937                                      const char *to_filename)
1938 {
1939         int from, to, err = -1;
1940
1941         from = open(from_filename, O_RDONLY);
1942         if (from < 0)
1943                 return -1;
1944
1945         to = open(to_filename, O_RDONLY);
1946         if (to < 0)
1947                 goto out_close_from;
1948
1949         err = kcore_copy__compare_fds(from, to);
1950
1951         close(to);
1952 out_close_from:
1953         close(from);
1954         return err;
1955 }
1956
1957 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1958                                     const char *name)
1959 {
1960         char from_filename[PATH_MAX];
1961         char to_filename[PATH_MAX];
1962
1963         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1964         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1965
1966         return kcore_copy__compare_files(from_filename, to_filename);
1967 }
1968
1969 /**
1970  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1971  * @from_dir: from directory
1972  * @to_dir: to directory
1973  *
1974  * This function copies kallsyms, modules and kcore files from one directory to
1975  * another.  kallsyms and modules are copied entirely.  Only code segments are
1976  * copied from kcore.  It is assumed that two segments suffice: one for the
1977  * kernel proper and one for all the modules.  The code segments are determined
1978  * from kallsyms and modules files.  The kernel map starts at _stext or the
1979  * lowest function symbol, and ends at _etext or the highest function symbol.
1980  * The module map starts at the lowest module address and ends at the highest
1981  * module symbol.  Start addresses are rounded down to the nearest page.  End
1982  * addresses are rounded up to the nearest page.  An extra page is added to the
1983  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1984  * symbol too.  Because it contains only code sections, the resulting kcore is
1985  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1986  * is not the same for the kernel map and the modules map.  That happens because
1987  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1988  * kallsyms and modules files are compared with their copies to check that
1989  * modules have not been loaded or unloaded while the copies were taking place.
1990  *
1991  * Return: %0 on success, %-1 on failure.
1992  */
1993 int kcore_copy(const char *from_dir, const char *to_dir)
1994 {
1995         struct kcore kcore;
1996         struct kcore extract;
1997         int idx = 0, err = -1;
1998         off_t offset, sz;
1999         struct kcore_copy_info kci = { .stext = 0, };
2000         char kcore_filename[PATH_MAX];
2001         char extract_filename[PATH_MAX];
2002         struct phdr_data *p;
2003
2004         INIT_LIST_HEAD(&kci.phdrs);
2005         INIT_LIST_HEAD(&kci.syms);
2006
2007         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2008                 return -1;
2009
2010         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2011                 goto out_unlink_kallsyms;
2012
2013         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2014         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2015
2016         if (kcore__open(&kcore, kcore_filename))
2017                 goto out_unlink_modules;
2018
2019         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2020                 goto out_kcore_close;
2021
2022         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2023                 goto out_kcore_close;
2024
2025         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2026                 goto out_extract_close;
2027
2028         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2029                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2030         offset = round_up(offset, page_size);
2031
2032         kcore_copy__for_each_phdr(&kci, p) {
2033                 off_t offs = p->rel + offset;
2034
2035                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2036                         goto out_extract_close;
2037         }
2038
2039         sz = kcore__write(&extract);
2040         if (sz < 0 || sz > offset)
2041                 goto out_extract_close;
2042
2043         kcore_copy__for_each_phdr(&kci, p) {
2044                 off_t offs = p->rel + offset;
2045
2046                 if (p->remaps)
2047                         continue;
2048                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2049                         goto out_extract_close;
2050         }
2051
2052         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
2053                 goto out_extract_close;
2054
2055         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2056                 goto out_extract_close;
2057
2058         err = 0;
2059
2060 out_extract_close:
2061         kcore__close(&extract);
2062         if (err)
2063                 unlink(extract_filename);
2064 out_kcore_close:
2065         kcore__close(&kcore);
2066 out_unlink_modules:
2067         if (err)
2068                 kcore_copy__unlink(to_dir, "modules");
2069 out_unlink_kallsyms:
2070         if (err)
2071                 kcore_copy__unlink(to_dir, "kallsyms");
2072
2073         kcore_copy__free_phdrs(&kci);
2074         kcore_copy__free_syms(&kci);
2075
2076         return err;
2077 }
2078
2079 int kcore_extract__create(struct kcore_extract *kce)
2080 {
2081         struct kcore kcore;
2082         struct kcore extract;
2083         size_t count = 1;
2084         int idx = 0, err = -1;
2085         off_t offset = page_size, sz;
2086
2087         if (kcore__open(&kcore, kce->kcore_filename))
2088                 return -1;
2089
2090         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2091         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2092                 goto out_kcore_close;
2093
2094         if (kcore__copy_hdr(&kcore, &extract, count))
2095                 goto out_extract_close;
2096
2097         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2098                 goto out_extract_close;
2099
2100         sz = kcore__write(&extract);
2101         if (sz < 0 || sz > offset)
2102                 goto out_extract_close;
2103
2104         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2105                 goto out_extract_close;
2106
2107         err = 0;
2108
2109 out_extract_close:
2110         kcore__close(&extract);
2111         if (err)
2112                 unlink(kce->extract_filename);
2113 out_kcore_close:
2114         kcore__close(&kcore);
2115
2116         return err;
2117 }
2118
2119 void kcore_extract__delete(struct kcore_extract *kce)
2120 {
2121         unlink(kce->extract_filename);
2122 }
2123
2124 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2125
2126 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2127 {
2128         if (!base_off)
2129                 return;
2130
2131         if (tmp->bit32)
2132                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2133                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2134                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2135         else
2136                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2137                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2138                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2139 }
2140
2141 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2142                               GElf_Addr base_off)
2143 {
2144         if (!base_off)
2145                 return;
2146
2147         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2148                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2149         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2150                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2151 }
2152
2153 /**
2154  * populate_sdt_note : Parse raw data and identify SDT note
2155  * @elf: elf of the opened file
2156  * @data: raw data of a section with description offset applied
2157  * @len: note description size
2158  * @type: type of the note
2159  * @sdt_notes: List to add the SDT note
2160  *
2161  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2162  * if its an SDT note, it appends to @sdt_notes list.
2163  */
2164 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2165                              struct list_head *sdt_notes)
2166 {
2167         const char *provider, *name, *args;
2168         struct sdt_note *tmp = NULL;
2169         GElf_Ehdr ehdr;
2170         GElf_Shdr shdr;
2171         int ret = -EINVAL;
2172
2173         union {
2174                 Elf64_Addr a64[NR_ADDR];
2175                 Elf32_Addr a32[NR_ADDR];
2176         } buf;
2177
2178         Elf_Data dst = {
2179                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2180                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2181                 .d_off = 0, .d_align = 0
2182         };
2183         Elf_Data src = {
2184                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2185                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2186                 .d_align = 0
2187         };
2188
2189         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2190         if (!tmp) {
2191                 ret = -ENOMEM;
2192                 goto out_err;
2193         }
2194
2195         INIT_LIST_HEAD(&tmp->note_list);
2196
2197         if (len < dst.d_size + 3)
2198                 goto out_free_note;
2199
2200         /* Translation from file representation to memory representation */
2201         if (gelf_xlatetom(*elf, &dst, &src,
2202                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2203                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2204                 goto out_free_note;
2205         }
2206
2207         /* Populate the fields of sdt_note */
2208         provider = data + dst.d_size;
2209
2210         name = (const char *)memchr(provider, '\0', data + len - provider);
2211         if (name++ == NULL)
2212                 goto out_free_note;
2213
2214         tmp->provider = strdup(provider);
2215         if (!tmp->provider) {
2216                 ret = -ENOMEM;
2217                 goto out_free_note;
2218         }
2219         tmp->name = strdup(name);
2220         if (!tmp->name) {
2221                 ret = -ENOMEM;
2222                 goto out_free_prov;
2223         }
2224
2225         args = memchr(name, '\0', data + len - name);
2226
2227         /*
2228          * There is no argument if:
2229          * - We reached the end of the note;
2230          * - There is not enough room to hold a potential string;
2231          * - The argument string is empty or just contains ':'.
2232          */
2233         if (args == NULL || data + len - args < 2 ||
2234                 args[1] == ':' || args[1] == '\0')
2235                 tmp->args = NULL;
2236         else {
2237                 tmp->args = strdup(++args);
2238                 if (!tmp->args) {
2239                         ret = -ENOMEM;
2240                         goto out_free_name;
2241                 }
2242         }
2243
2244         if (gelf_getclass(*elf) == ELFCLASS32) {
2245                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2246                 tmp->bit32 = true;
2247         } else {
2248                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2249                 tmp->bit32 = false;
2250         }
2251
2252         if (!gelf_getehdr(*elf, &ehdr)) {
2253                 pr_debug("%s : cannot get elf header.\n", __func__);
2254                 ret = -EBADF;
2255                 goto out_free_args;
2256         }
2257
2258         /* Adjust the prelink effect :
2259          * Find out the .stapsdt.base section.
2260          * This scn will help us to handle prelinking (if present).
2261          * Compare the retrieved file offset of the base section with the
2262          * base address in the description of the SDT note. If its different,
2263          * then accordingly, adjust the note location.
2264          */
2265         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2266                 sdt_adjust_loc(tmp, shdr.sh_offset);
2267
2268         /* Adjust reference counter offset */
2269         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2270                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2271
2272         list_add_tail(&tmp->note_list, sdt_notes);
2273         return 0;
2274
2275 out_free_args:
2276         zfree(&tmp->args);
2277 out_free_name:
2278         zfree(&tmp->name);
2279 out_free_prov:
2280         zfree(&tmp->provider);
2281 out_free_note:
2282         free(tmp);
2283 out_err:
2284         return ret;
2285 }
2286
2287 /**
2288  * construct_sdt_notes_list : constructs a list of SDT notes
2289  * @elf : elf to look into
2290  * @sdt_notes : empty list_head
2291  *
2292  * Scans the sections in 'elf' for the section
2293  * .note.stapsdt. It, then calls populate_sdt_note to find
2294  * out the SDT events and populates the 'sdt_notes'.
2295  */
2296 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2297 {
2298         GElf_Ehdr ehdr;
2299         Elf_Scn *scn = NULL;
2300         Elf_Data *data;
2301         GElf_Shdr shdr;
2302         size_t shstrndx, next;
2303         GElf_Nhdr nhdr;
2304         size_t name_off, desc_off, offset;
2305         int ret = 0;
2306
2307         if (gelf_getehdr(elf, &ehdr) == NULL) {
2308                 ret = -EBADF;
2309                 goto out_ret;
2310         }
2311         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2312                 ret = -EBADF;
2313                 goto out_ret;
2314         }
2315
2316         /* Look for the required section */
2317         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2318         if (!scn) {
2319                 ret = -ENOENT;
2320                 goto out_ret;
2321         }
2322
2323         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2324                 ret = -ENOENT;
2325                 goto out_ret;
2326         }
2327
2328         data = elf_getdata(scn, NULL);
2329
2330         /* Get the SDT notes */
2331         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2332                                               &desc_off)) > 0; offset = next) {
2333                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2334                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2335                             sizeof(SDT_NOTE_NAME))) {
2336                         /* Check the type of the note */
2337                         if (nhdr.n_type != SDT_NOTE_TYPE)
2338                                 goto out_ret;
2339
2340                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2341                                                 nhdr.n_descsz, sdt_notes);
2342                         if (ret < 0)
2343                                 goto out_ret;
2344                 }
2345         }
2346         if (list_empty(sdt_notes))
2347                 ret = -ENOENT;
2348
2349 out_ret:
2350         return ret;
2351 }
2352
2353 /**
2354  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2355  * @head : empty list_head
2356  * @target : file to find SDT notes from
2357  *
2358  * This opens the file, initializes
2359  * the ELF and then calls construct_sdt_notes_list.
2360  */
2361 int get_sdt_note_list(struct list_head *head, const char *target)
2362 {
2363         Elf *elf;
2364         int fd, ret;
2365
2366         fd = open(target, O_RDONLY);
2367         if (fd < 0)
2368                 return -EBADF;
2369
2370         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2371         if (!elf) {
2372                 ret = -EBADF;
2373                 goto out_close;
2374         }
2375         ret = construct_sdt_notes_list(elf, head);
2376         elf_end(elf);
2377 out_close:
2378         close(fd);
2379         return ret;
2380 }
2381
2382 /**
2383  * cleanup_sdt_note_list : free the sdt notes' list
2384  * @sdt_notes: sdt notes' list
2385  *
2386  * Free up the SDT notes in @sdt_notes.
2387  * Returns the number of SDT notes free'd.
2388  */
2389 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2390 {
2391         struct sdt_note *tmp, *pos;
2392         int nr_free = 0;
2393
2394         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2395                 list_del_init(&pos->note_list);
2396                 zfree(&pos->name);
2397                 zfree(&pos->provider);
2398                 free(pos);
2399                 nr_free++;
2400         }
2401         return nr_free;
2402 }
2403
2404 /**
2405  * sdt_notes__get_count: Counts the number of sdt events
2406  * @start: list_head to sdt_notes list
2407  *
2408  * Returns the number of SDT notes in a list
2409  */
2410 int sdt_notes__get_count(struct list_head *start)
2411 {
2412         struct sdt_note *sdt_ptr;
2413         int count = 0;
2414
2415         list_for_each_entry(sdt_ptr, start, note_list)
2416                 count++;
2417         return count;
2418 }
2419 #endif
2420
2421 void symbol__elf_init(void)
2422 {
2423         elf_version(EV_CURRENT);
2424 }