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-ocaml.h"
  16 #include "demangle-java.h"
  17 #include "demangle-rust.h"
  18 #include "machine.h"
  19 #include "vdso.h"
  20 #include "debug.h"
  21 #include "util/copyfile.h"
  22 #include <linux/ctype.h>
  23 #include <linux/kernel.h>
  24 #include <linux/zalloc.h>
  25 #include <symbol/kallsyms.h>
  26 #include <internal/lib.h>
  27
  28 #ifndef EM_AARCH64
  29 #define EM_AARCH64      183  /* ARM 64 bit */
  30 #endif
  31
  32 #ifndef ELF32_ST_VISIBILITY
  33 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  34 #endif
  35
  36 /* For ELF64 the definitions are the same.  */
  37 #ifndef ELF64_ST_VISIBILITY
  38 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  39 #endif
  40
  41 /* How to extract information held in the st_other field.  */
  42 #ifndef GELF_ST_VISIBILITY
  43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  44 #endif
  45
  46 typedef Elf64_Nhdr GElf_Nhdr;
  47
  48 #ifndef DMGL_PARAMS
  49 #define DMGL_NO_OPTS     0              /* For readability... */
  50 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  51 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  52 #endif
  53
  54 #ifdef HAVE_LIBBFD_SUPPORT
  55 #define PACKAGE 'perf'
  56 #include <bfd.h>
  57 #else
  58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  59 extern char *cplus_demangle(const char *, int);
  60
  61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  62 {
  63         return cplus_demangle(c, i);
  64 }
  65 #else
  66 #ifdef NO_DEMANGLE
  67 static inline char *bfd_demangle(void __maybe_unused *v,
  68                                  const char __maybe_unused *c,
  69                                  int __maybe_unused i)
  70 {
  71         return NULL;
  72 }
  73 #endif
  74 #endif
  75 #endif
  76
  77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  78 static int elf_getphdrnum(Elf *elf, size_t *dst)
  79 {
  80         GElf_Ehdr gehdr;
  81         GElf_Ehdr *ehdr;
  82
  83         ehdr = gelf_getehdr(elf, &gehdr);
  84         if (!ehdr)
  85                 return -1;
  86
  87         *dst = ehdr->e_phnum;
  88
  89         return 0;
  90 }
  91 #endif
  92
  93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  95 {
  96         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  97         return -1;
  98 }
  99 #endif
 100
 101 #ifndef NT_GNU_BUILD_ID
 102 #define NT_GNU_BUILD_ID 3
 103 #endif
 104
 105 /**
 106  * elf_symtab__for_each_symbol - iterate thru all the symbols
 107  *
 108  * @syms: struct elf_symtab instance to iterate
 109  * @idx: uint32_t idx
 110  * @sym: GElf_Sym iterator
 111  */
 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 113         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 114              idx < nr_syms; \
 115              idx++, gelf_getsym(syms, idx, &sym))
 116
 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 118 {
 119         return GELF_ST_TYPE(sym->st_info);
 120 }
 121
 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 123 {
 124         return GELF_ST_VISIBILITY(sym->st_other);
 125 }
 126
 127 #ifndef STT_GNU_IFUNC
 128 #define STT_GNU_IFUNC 10
 129 #endif
 130
 131 static inline int elf_sym__is_function(const GElf_Sym *sym)
 132 {
 133         return (elf_sym__type(sym) == STT_FUNC ||
 134                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 135                sym->st_name != 0 &&
 136                sym->st_shndx != SHN_UNDEF;
 137 }
 138
 139 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 140 {
 141         return elf_sym__type(sym) == STT_OBJECT &&
 142                 sym->st_name != 0 &&
 143                 sym->st_shndx != SHN_UNDEF;
 144 }
 145
 146 static inline int elf_sym__is_label(const GElf_Sym *sym)
 147 {
 148         return elf_sym__type(sym) == STT_NOTYPE &&
 149                 sym->st_name != 0 &&
 150                 sym->st_shndx != SHN_UNDEF &&
 151                 sym->st_shndx != SHN_ABS &&
 152                 elf_sym__visibility(sym) != STV_HIDDEN &&
 153                 elf_sym__visibility(sym) != STV_INTERNAL;
 154 }
 155
 156 static bool elf_sym__filter(GElf_Sym *sym)
 157 {
 158         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 159 }
 160
 161 static inline const char *elf_sym__name(const GElf_Sym *sym,
 162                                         const Elf_Data *symstrs)
 163 {
 164         return symstrs->d_buf + sym->st_name;
 165 }
 166
 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 168                                         const Elf_Data *secstrs)
 169 {
 170         return secstrs->d_buf + shdr->sh_name;
 171 }
 172
 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 174                                         const Elf_Data *secstrs)
 175 {
 176         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 177 }
 178
 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 180                                     const Elf_Data *secstrs)
 181 {
 182         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 183 }
 184
 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 186 {
 187         return elf_sec__is_text(shdr, secstrs) ||
 188                elf_sec__is_data(shdr, secstrs);
 189 }
 190
 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 192 {
 193         Elf_Scn *sec = NULL;
 194         GElf_Shdr shdr;
 195         size_t cnt = 1;
 196
 197         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 198                 gelf_getshdr(sec, &shdr);
 199
 200                 if ((addr >= shdr.sh_addr) &&
 201                     (addr < (shdr.sh_addr + shdr.sh_size)))
 202                         return cnt;
 203
 204                 ++cnt;
 205         }
 206
 207         return -1;
 208 }
 209
 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 211                              GElf_Shdr *shp, const char *name, size_t *idx)
 212 {
 213         Elf_Scn *sec = NULL;
 214         size_t cnt = 1;
 215
 216         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 217         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 218                 return NULL;
 219
 220         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 221                 char *str;
 222
 223                 gelf_getshdr(sec, shp);
 224                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 225                 if (str && !strcmp(name, str)) {
 226                         if (idx)
 227                                 *idx = cnt;
 228                         return sec;
 229                 }
 230                 ++cnt;
 231         }
 232
 233         return NULL;
 234 }
 235
 236 static bool want_demangle(bool is_kernel_sym)
 237 {
 238         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 239 }
 240
 241 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 242 {
 243         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 244         char *demangled = NULL;
 245
 246         /*
 247          * We need to figure out if the object was created from C++ sources
 248          * DWARF DW_compile_unit has this, but we don't always have access
 249          * to it...
 250          */
 251         if (!want_demangle(dso->kernel || kmodule))
 252             return demangled;
 253
 254         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 255         if (demangled == NULL) {
 256                 demangled = ocaml_demangle_sym(elf_name);
 257                 if (demangled == NULL) {
 258                         demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 259                 }
 260         }
 261         else if (rust_is_mangled(demangled))
 262                 /*
 263                     * Input to Rust demangling is the BFD-demangled
 264                     * name which it Rust-demangles in place.
 265                     */
 266                 rust_demangle_sym(demangled);
 267
 268         return demangled;
 269 }
 270
 271 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 272         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 273              idx < nr_entries; \
 274              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 275
 276 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 277         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 278              idx < nr_entries; \
 279              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 280
 281 /*
 282  * We need to check if we have a .dynsym, so that we can handle the
 283  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 284  * .dynsym or .symtab).
 285  * And always look at the original dso, not at debuginfo packages, that
 286  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 287  */
 288 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 289 {
 290         uint32_t nr_rel_entries, idx;
 291         GElf_Sym sym;
 292         u64 plt_offset, plt_header_size, plt_entry_size;
 293         GElf_Shdr shdr_plt;
 294         struct symbol *f;
 295         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 296         Elf_Data *reldata, *syms, *symstrs;
 297         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 298         size_t dynsym_idx;
 299         GElf_Ehdr ehdr;
 300         char sympltname[1024];
 301         Elf *elf;
 302         int nr = 0, symidx, err = 0;
 303
 304         if (!ss->dynsym)
 305                 return 0;
 306
 307         elf = ss->elf;
 308         ehdr = ss->ehdr;
 309
 310         scn_dynsym = ss->dynsym;
 311         shdr_dynsym = ss->dynshdr;
 312         dynsym_idx = ss->dynsym_idx;
 313
 314         if (scn_dynsym == NULL)
 315                 goto out_elf_end;
 316
 317         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 318                                           ".rela.plt", NULL);
 319         if (scn_plt_rel == NULL) {
 320                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 321                                                   ".rel.plt", NULL);
 322                 if (scn_plt_rel == NULL)
 323                         goto out_elf_end;
 324         }
 325
 326         err = -1;
 327
 328         if (shdr_rel_plt.sh_link != dynsym_idx)
 329                 goto out_elf_end;
 330
 331         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 332                 goto out_elf_end;
 333
 334         /*
 335          * Fetch the relocation section to find the idxes to the GOT
 336          * and the symbols in the .dynsym they refer to.
 337          */
 338         reldata = elf_getdata(scn_plt_rel, NULL);
 339         if (reldata == NULL)
 340                 goto out_elf_end;
 341
 342         syms = elf_getdata(scn_dynsym, NULL);
 343         if (syms == NULL)
 344                 goto out_elf_end;
 345
 346         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 347         if (scn_symstrs == NULL)
 348                 goto out_elf_end;
 349
 350         symstrs = elf_getdata(scn_symstrs, NULL);
 351         if (symstrs == NULL)
 352                 goto out_elf_end;
 353
 354         if (symstrs->d_size == 0)
 355                 goto out_elf_end;
 356
 357         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 358         plt_offset = shdr_plt.sh_offset;
 359         switch (ehdr.e_machine) {
 360                 case EM_ARM:
 361                         plt_header_size = 20;
 362                         plt_entry_size = 12;
 363                         break;
 364
 365                 case EM_AARCH64:
 366                         plt_header_size = 32;
 367                         plt_entry_size = 16;
 368                         break;
 369
 370                 case EM_SPARC:
 371                         plt_header_size = 48;
 372                         plt_entry_size = 12;
 373                         break;
 374
 375                 case EM_SPARCV9:
 376                         plt_header_size = 128;
 377                         plt_entry_size = 32;
 378                         break;
 379
 380                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 381                         plt_header_size = shdr_plt.sh_entsize;
 382                         plt_entry_size = shdr_plt.sh_entsize;
 383                         break;
 384         }
 385         plt_offset += plt_header_size;
 386
 387         if (shdr_rel_plt.sh_type == SHT_RELA) {
 388                 GElf_Rela pos_mem, *pos;
 389
 390                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 391                                            nr_rel_entries) {
 392                         const char *elf_name = NULL;
 393                         char *demangled = NULL;
 394                         symidx = GELF_R_SYM(pos->r_info);
 395                         gelf_getsym(syms, symidx, &sym);
 396
 397                         elf_name = elf_sym__name(&sym, symstrs);
 398                         demangled = demangle_sym(dso, 0, elf_name);
 399                         if (demangled != NULL)
 400                                 elf_name = demangled;
 401                         snprintf(sympltname, sizeof(sympltname),
 402                                  "%s@plt", elf_name);
 403                         free(demangled);
 404
 405                         f = symbol__new(plt_offset, plt_entry_size,
 406                                         STB_GLOBAL, STT_FUNC, sympltname);
 407                         if (!f)
 408                                 goto out_elf_end;
 409
 410                         plt_offset += plt_entry_size;
 411                         symbols__insert(&dso->symbols, f);
 412                         ++nr;
 413                 }
 414         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 415                 GElf_Rel pos_mem, *pos;
 416                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 417                                           nr_rel_entries) {
 418                         const char *elf_name = NULL;
 419                         char *demangled = NULL;
 420                         symidx = GELF_R_SYM(pos->r_info);
 421                         gelf_getsym(syms, symidx, &sym);
 422
 423                         elf_name = elf_sym__name(&sym, symstrs);
 424                         demangled = demangle_sym(dso, 0, elf_name);
 425                         if (demangled != NULL)
 426                                 elf_name = demangled;
 427                         snprintf(sympltname, sizeof(sympltname),
 428                                  "%s@plt", elf_name);
 429                         free(demangled);
 430
 431                         f = symbol__new(plt_offset, plt_entry_size,
 432                                         STB_GLOBAL, STT_FUNC, sympltname);
 433                         if (!f)
 434                                 goto out_elf_end;
 435
 436                         plt_offset += plt_entry_size;
 437                         symbols__insert(&dso->symbols, f);
 438                         ++nr;
 439                 }
 440         }
 441
 442         err = 0;
 443 out_elf_end:
 444         if (err == 0)
 445                 return nr;
 446         pr_debug("%s: problems reading %s PLT info.\n",
 447                  __func__, dso->long_name);
 448         return 0;
 449 }
 450
 451 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 452 {
 453         return demangle_sym(dso, kmodule, elf_name);
 454 }
 455
 456 /*
 457  * Align offset to 4 bytes as needed for note name and descriptor data.
 458  */
 459 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 460
 461 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 462 {
 463         int err = -1;
 464         GElf_Ehdr ehdr;
 465         GElf_Shdr shdr;
 466         Elf_Data *data;
 467         Elf_Scn *sec;
 468         Elf_Kind ek;
 469         void *ptr;
 470
 471         if (size < BUILD_ID_SIZE)
 472                 goto out;
 473
 474         ek = elf_kind(elf);
 475         if (ek != ELF_K_ELF)
 476                 goto out;
 477
 478         if (gelf_getehdr(elf, &ehdr) == NULL) {
 479                 pr_err("%s: cannot get elf header.\n", __func__);
 480                 goto out;
 481         }
 482
 483         /*
 484          * Check following sections for notes:
 485          *   '.note.gnu.build-id'
 486          *   '.notes'
 487          *   '.note' (VDSO specific)
 488          */
 489         do {
 490                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 491                                           ".note.gnu.build-id", NULL);
 492                 if (sec)
 493                         break;
 494
 495                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 496                                           ".notes", NULL);
 497                 if (sec)
 498                         break;
 499
 500                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 501                                           ".note", NULL);
 502                 if (sec)
 503                         break;
 504
 505                 return err;
 506
 507         } while (0);
 508
 509         data = elf_getdata(sec, NULL);
 510         if (data == NULL)
 511                 goto out;
 512
 513         ptr = data->d_buf;
 514         while (ptr < (data->d_buf + data->d_size)) {
 515                 GElf_Nhdr *nhdr = ptr;
 516                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 517                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 518                 const char *name;
 519
 520                 ptr += sizeof(*nhdr);
 521                 name = ptr;
 522                 ptr += namesz;
 523                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 524                     nhdr->n_namesz == sizeof("GNU")) {
 525                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 526                                 size_t sz = min(size, descsz);
 527                                 memcpy(bf, ptr, sz);
 528                                 memset(bf + sz, 0, size - sz);
 529                                 err = descsz;
 530                                 break;
 531                         }
 532                 }
 533                 ptr += descsz;
 534         }
 535
 536 out:
 537         return err;
 538 }
 539
 540 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
 541
 542 static int read_build_id(const char *filename, struct build_id *bid)
 543 {
 544         size_t size = sizeof(bid->data);
 545         int err = -1;
 546         bfd *abfd;
 547
 548         abfd = bfd_openr(filename, NULL);
 549         if (!abfd)
 550                 return -1;
 551
 552         if (!bfd_check_format(abfd, bfd_object)) {
 553                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 554                 goto out_close;
 555         }
 556
 557         if (!abfd->build_id || abfd->build_id->size > size)
 558                 goto out_close;
 559
 560         memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
 561         memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
 562         err = bid->size = abfd->build_id->size;
 563
 564 out_close:
 565         bfd_close(abfd);
 566         return err;
 567 }
 568
 569 #else // HAVE_LIBBFD_BUILDID_SUPPORT
 570
 571 static int read_build_id(const char *filename, struct build_id *bid)
 572 {
 573         size_t size = sizeof(bid->data);
 574         int fd, err = -1;
 575         Elf *elf;
 576
 577         if (size < BUILD_ID_SIZE)
 578                 goto out;
 579
 580         fd = open(filename, O_RDONLY);
 581         if (fd < 0)
 582                 goto out;
 583
 584         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 585         if (elf == NULL) {
 586                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 587                 goto out_close;
 588         }
 589
 590         err = elf_read_build_id(elf, bid->data, size);
 591         if (err > 0)
 592                 bid->size = err;
 593
 594         elf_end(elf);
 595 out_close:
 596         close(fd);
 597 out:
 598         return err;
 599 }
 600
 601 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 602
 603 int filename__read_build_id(const char *filename, struct build_id *bid)
 604 {
 605         struct kmod_path m = { .name = NULL, };
 606         char path[PATH_MAX];
 607         int err;
 608
 609         if (!filename)
 610                 return -EFAULT;
 611
 612         err = kmod_path__parse(&m, filename);
 613         if (err)
 614                 return -1;
 615
 616         if (m.comp) {
 617                 int error = 0, fd;
 618
 619                 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
 620                 if (fd < 0) {
 621                         pr_debug("Failed to decompress (error %d) %s\n",
 622                                  error, filename);
 623                         return -1;
 624                 }
 625                 close(fd);
 626                 filename = path;
 627         }
 628
 629         err = read_build_id(filename, bid);
 630
 631         if (m.comp)
 632                 unlink(filename);
 633         return err;
 634 }
 635
 636 int sysfs__read_build_id(const char *filename, struct build_id *bid)
 637 {
 638         size_t size = sizeof(bid->data);
 639         int fd, err = -1;
 640
 641         fd = open(filename, O_RDONLY);
 642         if (fd < 0)
 643                 goto out;
 644
 645         while (1) {
 646                 char bf[BUFSIZ];
 647                 GElf_Nhdr nhdr;
 648                 size_t namesz, descsz;
 649
 650                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 651                         break;
 652
 653                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 654                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 655                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 656                     nhdr.n_namesz == sizeof("GNU")) {
 657                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 658                                 break;
 659                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 660                                 size_t sz = min(descsz, size);
 661                                 if (read(fd, bid->data, sz) == (ssize_t)sz) {
 662                                         memset(bid->data + sz, 0, size - sz);
 663                                         bid->size = sz;
 664                                         err = 0;
 665                                         break;
 666                                 }
 667                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 668                                 break;
 669                 } else {
 670                         int n = namesz + descsz;
 671
 672                         if (n > (int)sizeof(bf)) {
 673                                 n = sizeof(bf);
 674                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 675                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 676                         }
 677                         if (read(fd, bf, n) != n)
 678                                 break;
 679                 }
 680         }
 681         close(fd);
 682 out:
 683         return err;
 684 }
 685
 686 #ifdef HAVE_LIBBFD_SUPPORT
 687
 688 int filename__read_debuglink(const char *filename, char *debuglink,
 689                              size_t size)
 690 {
 691         int err = -1;
 692         asection *section;
 693         bfd *abfd;
 694
 695         abfd = bfd_openr(filename, NULL);
 696         if (!abfd)
 697                 return -1;
 698
 699         if (!bfd_check_format(abfd, bfd_object)) {
 700                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 701                 goto out_close;
 702         }
 703
 704         section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
 705         if (!section)
 706                 goto out_close;
 707
 708         if (section->size > size)
 709                 goto out_close;
 710
 711         if (!bfd_get_section_contents(abfd, section, debuglink, 0,
 712                                       section->size))
 713                 goto out_close;
 714
 715         err = 0;
 716
 717 out_close:
 718         bfd_close(abfd);
 719         return err;
 720 }
 721
 722 #else
 723
 724 int filename__read_debuglink(const char *filename, char *debuglink,
 725                              size_t size)
 726 {
 727         int fd, err = -1;
 728         Elf *elf;
 729         GElf_Ehdr ehdr;
 730         GElf_Shdr shdr;
 731         Elf_Data *data;
 732         Elf_Scn *sec;
 733         Elf_Kind ek;
 734
 735         fd = open(filename, O_RDONLY);
 736         if (fd < 0)
 737                 goto out;
 738
 739         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 740         if (elf == NULL) {
 741                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 742                 goto out_close;
 743         }
 744
 745         ek = elf_kind(elf);
 746         if (ek != ELF_K_ELF)
 747                 goto out_elf_end;
 748
 749         if (gelf_getehdr(elf, &ehdr) == NULL) {
 750                 pr_err("%s: cannot get elf header.\n", __func__);
 751                 goto out_elf_end;
 752         }
 753
 754         sec = elf_section_by_name(elf, &ehdr, &shdr,
 755                                   ".gnu_debuglink", NULL);
 756         if (sec == NULL)
 757                 goto out_elf_end;
 758
 759         data = elf_getdata(sec, NULL);
 760         if (data == NULL)
 761                 goto out_elf_end;
 762
 763         /* the start of this section is a zero-terminated string */
 764         strncpy(debuglink, data->d_buf, size);
 765
 766         err = 0;
 767
 768 out_elf_end:
 769         elf_end(elf);
 770 out_close:
 771         close(fd);
 772 out:
 773         return err;
 774 }
 775
 776 #endif
 777
 778 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 779 {
 780         static unsigned int const endian = 1;
 781
 782         dso->needs_swap = DSO_SWAP__NO;
 783
 784         switch (eidata) {
 785         case ELFDATA2LSB:
 786                 /* We are big endian, DSO is little endian. */
 787                 if (*(unsigned char const *)&endian != 1)
 788                         dso->needs_swap = DSO_SWAP__YES;
 789                 break;
 790
 791         case ELFDATA2MSB:
 792                 /* We are little endian, DSO is big endian. */
 793                 if (*(unsigned char const *)&endian != 0)
 794                         dso->needs_swap = DSO_SWAP__YES;
 795                 break;
 796
 797         default:
 798                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 799                 return -EINVAL;
 800         }
 801
 802         return 0;
 803 }
 804
 805 bool symsrc__possibly_runtime(struct symsrc *ss)
 806 {
 807         return ss->dynsym || ss->opdsec;
 808 }
 809
 810 bool symsrc__has_symtab(struct symsrc *ss)
 811 {
 812         return ss->symtab != NULL;
 813 }
 814
 815 void symsrc__destroy(struct symsrc *ss)
 816 {
 817         zfree(&ss->name);
 818         elf_end(ss->elf);
 819         close(ss->fd);
 820 }
 821
 822 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 823 {
 824         /*
 825          * Usually vmlinux is an ELF file with type ET_EXEC for most
 826          * architectures; except Arm64 kernel is linked with option
 827          * '-share', so need to check type ET_DYN.
 828          */
 829         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
 830                ehdr.e_type == ET_DYN;
 831 }
 832
 833 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 834                  enum dso_binary_type type)
 835 {
 836         GElf_Ehdr ehdr;
 837         Elf *elf;
 838         int fd;
 839
 840         if (dso__needs_decompress(dso)) {
 841                 fd = dso__decompress_kmodule_fd(dso, name);
 842                 if (fd < 0)
 843                         return -1;
 844
 845                 type = dso->symtab_type;
 846         } else {
 847                 fd = open(name, O_RDONLY);
 848                 if (fd < 0) {
 849                         dso->load_errno = errno;
 850                         return -1;
 851                 }
 852         }
 853
 854         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 855         if (elf == NULL) {
 856                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 857                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 858                 goto out_close;
 859         }
 860
 861         if (gelf_getehdr(elf, &ehdr) == NULL) {
 862                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 863                 pr_debug("%s: cannot get elf header.\n", __func__);
 864                 goto out_elf_end;
 865         }
 866
 867         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 868                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 869                 goto out_elf_end;
 870         }
 871
 872         /* Always reject images with a mismatched build-id: */
 873         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 874                 u8 build_id[BUILD_ID_SIZE];
 875                 struct build_id bid;
 876                 int size;
 877
 878                 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
 879                 if (size <= 0) {
 880                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 881                         goto out_elf_end;
 882                 }
 883
 884                 build_id__init(&bid, build_id, size);
 885                 if (!dso__build_id_equal(dso, &bid)) {
 886                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 887                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 888                         goto out_elf_end;
 889                 }
 890         }
 891
 892         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 893
 894         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 895                         NULL);
 896         if (ss->symshdr.sh_type != SHT_SYMTAB)
 897                 ss->symtab = NULL;
 898
 899         ss->dynsym_idx = 0;
 900         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 901                         &ss->dynsym_idx);
 902         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 903                 ss->dynsym = NULL;
 904
 905         ss->opdidx = 0;
 906         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 907                         &ss->opdidx);
 908         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 909                 ss->opdsec = NULL;
 910
 911         if (dso->kernel == DSO_SPACE__USER)
 912                 ss->adjust_symbols = true;
 913         else
 914                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 915
 916         ss->name   = strdup(name);
 917         if (!ss->name) {
 918                 dso->load_errno = errno;
 919                 goto out_elf_end;
 920         }
 921
 922         ss->elf    = elf;
 923         ss->fd     = fd;
 924         ss->ehdr   = ehdr;
 925         ss->type   = type;
 926
 927         return 0;
 928
 929 out_elf_end:
 930         elf_end(elf);
 931 out_close:
 932         close(fd);
 933         return -1;
 934 }
 935
 936 /**
 937  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 938  * @kmap: kernel maps and relocation reference symbol
 939  *
 940  * This function returns %true if we are dealing with the kernel maps and the
 941  * relocation reference symbol has not yet been found.  Otherwise %false is
 942  * returned.
 943  */
 944 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 945 {
 946         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 947                !kmap->ref_reloc_sym->unrelocated_addr;
 948 }
 949
 950 /**
 951  * ref_reloc - kernel relocation offset.
 952  * @kmap: kernel maps and relocation reference symbol
 953  *
 954  * This function returns the offset of kernel addresses as determined by using
 955  * the relocation reference symbol i.e. if the kernel has not been relocated
 956  * then the return value is zero.
 957  */
 958 static u64 ref_reloc(struct kmap *kmap)
 959 {
 960         if (kmap && kmap->ref_reloc_sym &&
 961             kmap->ref_reloc_sym->unrelocated_addr)
 962                 return kmap->ref_reloc_sym->addr -
 963                        kmap->ref_reloc_sym->unrelocated_addr;
 964         return 0;
 965 }
 966
 967 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 968                 GElf_Sym *sym __maybe_unused) { }
 969
 970 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 971                                       GElf_Sym *sym, GElf_Shdr *shdr,
 972                                       struct maps *kmaps, struct kmap *kmap,
 973                                       struct dso **curr_dsop, struct map **curr_mapp,
 974                                       const char *section_name,
 975                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 976 {
 977         struct dso *curr_dso = *curr_dsop;
 978         struct map *curr_map;
 979         char dso_name[PATH_MAX];
 980
 981         /* Adjust symbol to map to file offset */
 982         if (adjust_kernel_syms)
 983                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 984
 985         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 986                 return 0;
 987
 988         if (strcmp(section_name, ".text") == 0) {
 989                 /*
 990                  * The initial kernel mapping is based on
 991                  * kallsyms and identity maps.  Overwrite it to
 992                  * map to the kernel dso.
 993                  */
 994                 if (*remap_kernel && dso->kernel && !kmodule) {
 995                         *remap_kernel = false;
 996                         map->start = shdr->sh_addr + ref_reloc(kmap);
 997                         map->end = map->start + shdr->sh_size;
 998                         map->pgoff = shdr->sh_offset;
 999                         map->map_ip = map__map_ip;
1000                         map->unmap_ip = map__unmap_ip;
1001                         /* Ensure maps are correctly ordered */
1002                         if (kmaps) {
1003                                 map__get(map);
1004                                 maps__remove(kmaps, map);
1005                                 maps__insert(kmaps, map);
1006                                 map__put(map);
1007                         }
1008                 }
1009
1010                 /*
1011                  * The initial module mapping is based on
1012                  * /proc/modules mapped to offset zero.
1013                  * Overwrite it to map to the module dso.
1014                  */
1015                 if (*remap_kernel && kmodule) {
1016                         *remap_kernel = false;
1017                         map->pgoff = shdr->sh_offset;
1018                 }
1019
1020                 *curr_mapp = map;
1021                 *curr_dsop = dso;
1022                 return 0;
1023         }
1024
1025         if (!kmap)
1026                 return 0;
1027
1028         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1029
1030         curr_map = maps__find_by_name(kmaps, dso_name);
1031         if (curr_map == NULL) {
1032                 u64 start = sym->st_value;
1033
1034                 if (kmodule)
1035                         start += map->start + shdr->sh_offset;
1036
1037                 curr_dso = dso__new(dso_name);
1038                 if (curr_dso == NULL)
1039                         return -1;
1040                 curr_dso->kernel = dso->kernel;
1041                 curr_dso->long_name = dso->long_name;
1042                 curr_dso->long_name_len = dso->long_name_len;
1043                 curr_map = map__new2(start, curr_dso);
1044                 dso__put(curr_dso);
1045                 if (curr_map == NULL)
1046                         return -1;
1047
1048                 if (curr_dso->kernel)
1049                         map__kmap(curr_map)->kmaps = kmaps;
1050
1051                 if (adjust_kernel_syms) {
1052                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
1053                         curr_map->end    = curr_map->start + shdr->sh_size;
1054                         curr_map->pgoff  = shdr->sh_offset;
1055                 } else {
1056                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1057                 }
1058                 curr_dso->symtab_type = dso->symtab_type;
1059                 maps__insert(kmaps, curr_map);
1060                 /*
1061                  * Add it before we drop the reference to curr_map, i.e. while
1062                  * we still are sure to have a reference to this DSO via
1063                  * *curr_map->dso.
1064                  */
1065                 dsos__add(&kmaps->machine->dsos, curr_dso);
1066                 /* kmaps already got it */
1067                 map__put(curr_map);
1068                 dso__set_loaded(curr_dso);
1069                 *curr_mapp = curr_map;
1070                 *curr_dsop = curr_dso;
1071         } else
1072                 *curr_dsop = curr_map->dso;
1073
1074         return 0;
1075 }
1076
1077 static int
1078 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1079                        struct symsrc *runtime_ss, int kmodule, int dynsym)
1080 {
1081         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1082         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1083         struct map *curr_map = map;
1084         struct dso *curr_dso = dso;
1085         Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1086         uint32_t nr_syms;
1087         int err = -1;
1088         uint32_t idx;
1089         GElf_Ehdr ehdr;
1090         GElf_Shdr shdr;
1091         GElf_Shdr tshdr;
1092         Elf_Data *syms, *opddata = NULL;
1093         GElf_Sym sym;
1094         Elf_Scn *sec, *sec_strndx;
1095         Elf *elf;
1096         int nr = 0;
1097         bool remap_kernel = false, adjust_kernel_syms = false;
1098
1099         if (kmap && !kmaps)
1100                 return -1;
1101
1102         elf = syms_ss->elf;
1103         ehdr = syms_ss->ehdr;
1104         if (dynsym) {
1105                 sec  = syms_ss->dynsym;
1106                 shdr = syms_ss->dynshdr;
1107         } else {
1108                 sec =  syms_ss->symtab;
1109                 shdr = syms_ss->symshdr;
1110         }
1111
1112         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1113                                 ".text", NULL))
1114                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1115
1116         if (runtime_ss->opdsec)
1117                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1118
1119         syms = elf_getdata(sec, NULL);
1120         if (syms == NULL)
1121                 goto out_elf_end;
1122
1123         sec = elf_getscn(elf, shdr.sh_link);
1124         if (sec == NULL)
1125                 goto out_elf_end;
1126
1127         symstrs = elf_getdata(sec, NULL);
1128         if (symstrs == NULL)
1129                 goto out_elf_end;
1130
1131         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1132         if (sec_strndx == NULL)
1133                 goto out_elf_end;
1134
1135         secstrs_run = elf_getdata(sec_strndx, NULL);
1136         if (secstrs_run == NULL)
1137                 goto out_elf_end;
1138
1139         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1140         if (sec_strndx == NULL)
1141                 goto out_elf_end;
1142
1143         secstrs_sym = elf_getdata(sec_strndx, NULL);
1144         if (secstrs_sym == NULL)
1145                 goto out_elf_end;
1146
1147         nr_syms = shdr.sh_size / shdr.sh_entsize;
1148
1149         memset(&sym, 0, sizeof(sym));
1150
1151         /*
1152          * The kernel relocation symbol is needed in advance in order to adjust
1153          * kernel maps correctly.
1154          */
1155         if (ref_reloc_sym_not_found(kmap)) {
1156                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1157                         const char *elf_name = elf_sym__name(&sym, symstrs);
1158
1159                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1160                                 continue;
1161                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1162                         map->reloc = kmap->ref_reloc_sym->addr -
1163                                      kmap->ref_reloc_sym->unrelocated_addr;
1164                         break;
1165                 }
1166         }
1167
1168         /*
1169          * Handle any relocation of vdso necessary because older kernels
1170          * attempted to prelink vdso to its virtual address.
1171          */
1172         if (dso__is_vdso(dso))
1173                 map->reloc = map->start - dso->text_offset;
1174
1175         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1176         /*
1177          * Initial kernel and module mappings do not map to the dso.
1178          * Flag the fixups.
1179          */
1180         if (dso->kernel) {
1181                 remap_kernel = true;
1182                 adjust_kernel_syms = dso->adjust_symbols;
1183         }
1184         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1185                 struct symbol *f;
1186                 const char *elf_name = elf_sym__name(&sym, symstrs);
1187                 char *demangled = NULL;
1188                 int is_label = elf_sym__is_label(&sym);
1189                 const char *section_name;
1190                 bool used_opd = false;
1191
1192                 if (!is_label && !elf_sym__filter(&sym))
1193                         continue;
1194
1195                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1196                  * don't identify functions, so will confuse the profile
1197                  * output: */
1198                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1199                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1200                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1201                                 continue;
1202                 }
1203
1204                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1205                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1206                         u64 *opd = opddata->d_buf + offset;
1207                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1208                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1209                                         sym.st_value);
1210                         used_opd = true;
1211                 }
1212                 /*
1213                  * When loading symbols in a data mapping, ABS symbols (which
1214                  * has a value of SHN_ABS in its st_shndx) failed at
1215                  * elf_getscn().  And it marks the loading as a failure so
1216                  * already loaded symbols cannot be fixed up.
1217                  *
1218                  * I'm not sure what should be done. Just ignore them for now.
1219                  * - Namhyung Kim
1220                  */
1221                 if (sym.st_shndx == SHN_ABS)
1222                         continue;
1223
1224                 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1225                 if (!sec)
1226                         goto out_elf_end;
1227
1228                 gelf_getshdr(sec, &shdr);
1229
1230                 secstrs = secstrs_sym;
1231
1232                 /*
1233                  * We have to fallback to runtime when syms' section header has
1234                  * NOBITS set. NOBITS results in file offset (sh_offset) not
1235                  * being incremented. So sh_offset used below has different
1236                  * values for syms (invalid) and runtime (valid).
1237                  */
1238                 if (shdr.sh_type == SHT_NOBITS) {
1239                         sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1240                         if (!sec)
1241                                 goto out_elf_end;
1242
1243                         gelf_getshdr(sec, &shdr);
1244                         secstrs = secstrs_run;
1245                 }
1246
1247                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1248                         continue;
1249
1250                 section_name = elf_sec__name(&shdr, secstrs);
1251
1252                 /* On ARM, symbols for thumb functions have 1 added to
1253                  * the symbol address as a flag - remove it */
1254                 if ((ehdr.e_machine == EM_ARM) &&
1255                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1256                     (sym.st_value & 1))
1257                         --sym.st_value;
1258
1259                 if (dso->kernel) {
1260                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1261                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1262                                 goto out_elf_end;
1263                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1264                            (!used_opd && syms_ss->adjust_symbols)) {
1265                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1266                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1267                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1268                                   (u64)shdr.sh_offset);
1269                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1270                 }
1271
1272                 demangled = demangle_sym(dso, kmodule, elf_name);
1273                 if (demangled != NULL)
1274                         elf_name = demangled;
1275
1276                 f = symbol__new(sym.st_value, sym.st_size,
1277                                 GELF_ST_BIND(sym.st_info),
1278                                 GELF_ST_TYPE(sym.st_info), elf_name);
1279                 free(demangled);
1280                 if (!f)
1281                         goto out_elf_end;
1282
1283                 arch__sym_update(f, &sym);
1284
1285                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1286                 nr++;
1287         }
1288
1289         /*
1290          * For misannotated, zeroed, ASM function sizes.
1291          */
1292         if (nr > 0) {
1293                 symbols__fixup_end(&dso->symbols);
1294                 symbols__fixup_duplicate(&dso->symbols);
1295                 if (kmap) {
1296                         /*
1297                          * We need to fixup this here too because we create new
1298                          * maps here, for things like vsyscall sections.
1299                          */
1300                         maps__fixup_end(kmaps);
1301                 }
1302         }
1303         err = nr;
1304 out_elf_end:
1305         return err;
1306 }
1307
1308 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1309                   struct symsrc *runtime_ss, int kmodule)
1310 {
1311         int nr = 0;
1312         int err = -1;
1313
1314         dso->symtab_type = syms_ss->type;
1315         dso->is_64_bit = syms_ss->is_64_bit;
1316         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1317
1318         /*
1319          * Modules may already have symbols from kallsyms, but those symbols
1320          * have the wrong values for the dso maps, so remove them.
1321          */
1322         if (kmodule && syms_ss->symtab)
1323                 symbols__delete(&dso->symbols);
1324
1325         if (!syms_ss->symtab) {
1326                 /*
1327                  * If the vmlinux is stripped, fail so we will fall back
1328                  * to using kallsyms. The vmlinux runtime symbols aren't
1329                  * of much use.
1330                  */
1331                 if (dso->kernel)
1332                         return err;
1333         } else  {
1334                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1335                                              kmodule, 0);
1336                 if (err < 0)
1337                         return err;
1338                 nr = err;
1339         }
1340
1341         if (syms_ss->dynsym) {
1342                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1343                                              kmodule, 1);
1344                 if (err < 0)
1345                         return err;
1346                 err += nr;
1347         }
1348
1349         return err;
1350 }
1351
1352 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1353 {
1354         GElf_Phdr phdr;
1355         size_t i, phdrnum;
1356         int err;
1357         u64 sz;
1358
1359         if (elf_getphdrnum(elf, &phdrnum))
1360                 return -1;
1361
1362         for (i = 0; i < phdrnum; i++) {
1363                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1364                         return -1;
1365                 if (phdr.p_type != PT_LOAD)
1366                         continue;
1367                 if (exe) {
1368                         if (!(phdr.p_flags & PF_X))
1369                                 continue;
1370                 } else {
1371                         if (!(phdr.p_flags & PF_R))
1372                                 continue;
1373                 }
1374                 sz = min(phdr.p_memsz, phdr.p_filesz);
1375                 if (!sz)
1376                         continue;
1377                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1378                 if (err)
1379                         return err;
1380         }
1381         return 0;
1382 }
1383
1384 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1385                     bool *is_64_bit)
1386 {
1387         int err;
1388         Elf *elf;
1389
1390         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1391         if (elf == NULL)
1392                 return -1;
1393
1394         if (is_64_bit)
1395                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1396
1397         err = elf_read_maps(elf, exe, mapfn, data);
1398
1399         elf_end(elf);
1400         return err;
1401 }
1402
1403 enum dso_type dso__type_fd(int fd)
1404 {
1405         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1406         GElf_Ehdr ehdr;
1407         Elf_Kind ek;
1408         Elf *elf;
1409
1410         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1411         if (elf == NULL)
1412                 goto out;
1413
1414         ek = elf_kind(elf);
1415         if (ek != ELF_K_ELF)
1416                 goto out_end;
1417
1418         if (gelf_getclass(elf) == ELFCLASS64) {
1419                 dso_type = DSO__TYPE_64BIT;
1420                 goto out_end;
1421         }
1422
1423         if (gelf_getehdr(elf, &ehdr) == NULL)
1424                 goto out_end;
1425
1426         if (ehdr.e_machine == EM_X86_64)
1427                 dso_type = DSO__TYPE_X32BIT;
1428         else
1429                 dso_type = DSO__TYPE_32BIT;
1430 out_end:
1431         elf_end(elf);
1432 out:
1433         return dso_type;
1434 }
1435
1436 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1437 {
1438         ssize_t r;
1439         size_t n;
1440         int err = -1;
1441         char *buf = malloc(page_size);
1442
1443         if (buf == NULL)
1444                 return -1;
1445
1446         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1447                 goto out;
1448
1449         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1450                 goto out;
1451
1452         while (len) {
1453                 n = page_size;
1454                 if (len < n)
1455                         n = len;
1456                 /* Use read because mmap won't work on proc files */
1457                 r = read(from, buf, n);
1458                 if (r < 0)
1459                         goto out;
1460                 if (!r)
1461                         break;
1462                 n = r;
1463                 r = write(to, buf, n);
1464                 if (r < 0)
1465                         goto out;
1466                 if ((size_t)r != n)
1467                         goto out;
1468                 len -= n;
1469         }
1470
1471         err = 0;
1472 out:
1473         free(buf);
1474         return err;
1475 }
1476
1477 struct kcore {
1478         int fd;
1479         int elfclass;
1480         Elf *elf;
1481         GElf_Ehdr ehdr;
1482 };
1483
1484 static int kcore__open(struct kcore *kcore, const char *filename)
1485 {
1486         GElf_Ehdr *ehdr;
1487
1488         kcore->fd = open(filename, O_RDONLY);
1489         if (kcore->fd == -1)
1490                 return -1;
1491
1492         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1493         if (!kcore->elf)
1494                 goto out_close;
1495
1496         kcore->elfclass = gelf_getclass(kcore->elf);
1497         if (kcore->elfclass == ELFCLASSNONE)
1498                 goto out_end;
1499
1500         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1501         if (!ehdr)
1502                 goto out_end;
1503
1504         return 0;
1505
1506 out_end:
1507         elf_end(kcore->elf);
1508 out_close:
1509         close(kcore->fd);
1510         return -1;
1511 }
1512
1513 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1514                        bool temp)
1515 {
1516         kcore->elfclass = elfclass;
1517
1518         if (temp)
1519                 kcore->fd = mkstemp(filename);
1520         else
1521                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1522         if (kcore->fd == -1)
1523                 return -1;
1524
1525         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1526         if (!kcore->elf)
1527                 goto out_close;
1528
1529         if (!gelf_newehdr(kcore->elf, elfclass))
1530                 goto out_end;
1531
1532         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1533
1534         return 0;
1535
1536 out_end:
1537         elf_end(kcore->elf);
1538 out_close:
1539         close(kcore->fd);
1540         unlink(filename);
1541         return -1;
1542 }
1543
1544 static void kcore__close(struct kcore *kcore)
1545 {
1546         elf_end(kcore->elf);
1547         close(kcore->fd);
1548 }
1549
1550 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1551 {
1552         GElf_Ehdr *ehdr = &to->ehdr;
1553         GElf_Ehdr *kehdr = &from->ehdr;
1554
1555         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1556         ehdr->e_type      = kehdr->e_type;
1557         ehdr->e_machine   = kehdr->e_machine;
1558         ehdr->e_version   = kehdr->e_version;
1559         ehdr->e_entry     = 0;
1560         ehdr->e_shoff     = 0;
1561         ehdr->e_flags     = kehdr->e_flags;
1562         ehdr->e_phnum     = count;
1563         ehdr->e_shentsize = 0;
1564         ehdr->e_shnum     = 0;
1565         ehdr->e_shstrndx  = 0;
1566
1567         if (from->elfclass == ELFCLASS32) {
1568                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1569                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1570                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1571         } else {
1572                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1573                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1574                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1575         }
1576
1577         if (!gelf_update_ehdr(to->elf, ehdr))
1578                 return -1;
1579
1580         if (!gelf_newphdr(to->elf, count))
1581                 return -1;
1582
1583         return 0;
1584 }
1585
1586 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1587                            u64 addr, u64 len)
1588 {
1589         GElf_Phdr phdr = {
1590                 .p_type         = PT_LOAD,
1591                 .p_flags        = PF_R | PF_W | PF_X,
1592                 .p_offset       = offset,
1593                 .p_vaddr        = addr,
1594                 .p_paddr        = 0,
1595                 .p_filesz       = len,
1596                 .p_memsz        = len,
1597                 .p_align        = page_size,
1598         };
1599
1600         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1601                 return -1;
1602
1603         return 0;
1604 }
1605
1606 static off_t kcore__write(struct kcore *kcore)
1607 {
1608         return elf_update(kcore->elf, ELF_C_WRITE);
1609 }
1610
1611 struct phdr_data {
1612         off_t offset;
1613         off_t rel;
1614         u64 addr;
1615         u64 len;
1616         struct list_head node;
1617         struct phdr_data *remaps;
1618 };
1619
1620 struct sym_data {
1621         u64 addr;
1622         struct list_head node;
1623 };
1624
1625 struct kcore_copy_info {
1626         u64 stext;
1627         u64 etext;
1628         u64 first_symbol;
1629         u64 last_symbol;
1630         u64 first_module;
1631         u64 first_module_symbol;
1632         u64 last_module_symbol;
1633         size_t phnum;
1634         struct list_head phdrs;
1635         struct list_head syms;
1636 };
1637
1638 #define kcore_copy__for_each_phdr(k, p) \
1639         list_for_each_entry((p), &(k)->phdrs, node)
1640
1641 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1642 {
1643         struct phdr_data *p = zalloc(sizeof(*p));
1644
1645         if (p) {
1646                 p->addr   = addr;
1647                 p->len    = len;
1648                 p->offset = offset;
1649         }
1650
1651         return p;
1652 }
1653
1654 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1655                                                  u64 addr, u64 len,
1656                                                  off_t offset)
1657 {
1658         struct phdr_data *p = phdr_data__new(addr, len, offset);
1659
1660         if (p)
1661                 list_add_tail(&p->node, &kci->phdrs);
1662
1663         return p;
1664 }
1665
1666 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1667 {
1668         struct phdr_data *p, *tmp;
1669
1670         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1671                 list_del_init(&p->node);
1672                 free(p);
1673         }
1674 }
1675
1676 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1677                                             u64 addr)
1678 {
1679         struct sym_data *s = zalloc(sizeof(*s));
1680
1681         if (s) {
1682                 s->addr = addr;
1683                 list_add_tail(&s->node, &kci->syms);
1684         }
1685
1686         return s;
1687 }
1688
1689 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1690 {
1691         struct sym_data *s, *tmp;
1692
1693         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1694                 list_del_init(&s->node);
1695                 free(s);
1696         }
1697 }
1698
1699 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1700                                         u64 start)
1701 {
1702         struct kcore_copy_info *kci = arg;
1703
1704         if (!kallsyms__is_function(type))
1705                 return 0;
1706
1707         if (strchr(name, '[')) {
1708                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1709                         kci->first_module_symbol = start;
1710                 if (start > kci->last_module_symbol)
1711                         kci->last_module_symbol = start;
1712                 return 0;
1713         }
1714
1715         if (!kci->first_symbol || start < kci->first_symbol)
1716                 kci->first_symbol = start;
1717
1718         if (!kci->last_symbol || start > kci->last_symbol)
1719                 kci->last_symbol = start;
1720
1721         if (!strcmp(name, "_stext")) {
1722                 kci->stext = start;
1723                 return 0;
1724         }
1725
1726         if (!strcmp(name, "_etext")) {
1727                 kci->etext = start;
1728                 return 0;
1729         }
1730
1731         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1732                 return -1;
1733
1734         return 0;
1735 }
1736
1737 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1738                                       const char *dir)
1739 {
1740         char kallsyms_filename[PATH_MAX];
1741
1742         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1743
1744         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1745                 return -1;
1746
1747         if (kallsyms__parse(kallsyms_filename, kci,
1748                             kcore_copy__process_kallsyms) < 0)
1749                 return -1;
1750
1751         return 0;
1752 }
1753
1754 static int kcore_copy__process_modules(void *arg,
1755                                        const char *name __maybe_unused,
1756                                        u64 start, u64 size __maybe_unused)
1757 {
1758         struct kcore_copy_info *kci = arg;
1759
1760         if (!kci->first_module || start < kci->first_module)
1761                 kci->first_module = start;
1762
1763         return 0;
1764 }
1765
1766 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1767                                      const char *dir)
1768 {
1769         char modules_filename[PATH_MAX];
1770
1771         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1772
1773         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1774                 return -1;
1775
1776         if (modules__parse(modules_filename, kci,
1777                            kcore_copy__process_modules) < 0)
1778                 return -1;
1779
1780         return 0;
1781 }
1782
1783 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1784                            u64 pgoff, u64 s, u64 e)
1785 {
1786         u64 len, offset;
1787
1788         if (s < start || s >= end)
1789                 return 0;
1790
1791         offset = (s - start) + pgoff;
1792         len = e < end ? e - s : end - s;
1793
1794         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1795 }
1796
1797 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1798 {
1799         struct kcore_copy_info *kci = data;
1800         u64 end = start + len;
1801         struct sym_data *sdat;
1802
1803         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1804                 return -1;
1805
1806         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1807                             kci->last_module_symbol))
1808                 return -1;
1809
1810         list_for_each_entry(sdat, &kci->syms, node) {
1811                 u64 s = round_down(sdat->addr, page_size);
1812
1813                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1814                         return -1;
1815         }
1816
1817         return 0;
1818 }
1819
1820 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1821 {
1822         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1823                 return -1;
1824
1825         return 0;
1826 }
1827
1828 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1829 {
1830         struct phdr_data *p, *k = NULL;
1831         u64 kend;
1832
1833         if (!kci->stext)
1834                 return;
1835
1836         /* Find phdr that corresponds to the kernel map (contains stext) */
1837         kcore_copy__for_each_phdr(kci, p) {
1838                 u64 pend = p->addr + p->len - 1;
1839
1840                 if (p->addr <= kci->stext && pend >= kci->stext) {
1841                         k = p;
1842                         break;
1843                 }
1844         }
1845
1846         if (!k)
1847                 return;
1848
1849         kend = k->offset + k->len;
1850
1851         /* Find phdrs that remap the kernel */
1852         kcore_copy__for_each_phdr(kci, p) {
1853                 u64 pend = p->offset + p->len;
1854
1855                 if (p == k)
1856                         continue;
1857
1858                 if (p->offset >= k->offset && pend <= kend)
1859                         p->remaps = k;
1860         }
1861 }
1862
1863 static void kcore_copy__layout(struct kcore_copy_info *kci)
1864 {
1865         struct phdr_data *p;
1866         off_t rel = 0;
1867
1868         kcore_copy__find_remaps(kci);
1869
1870         kcore_copy__for_each_phdr(kci, p) {
1871                 if (!p->remaps) {
1872                         p->rel = rel;
1873                         rel += p->len;
1874                 }
1875                 kci->phnum += 1;
1876         }
1877
1878         kcore_copy__for_each_phdr(kci, p) {
1879                 struct phdr_data *k = p->remaps;
1880
1881                 if (k)
1882                         p->rel = p->offset - k->offset + k->rel;
1883         }
1884 }
1885
1886 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1887                                  Elf *elf)
1888 {
1889         if (kcore_copy__parse_kallsyms(kci, dir))
1890                 return -1;
1891
1892         if (kcore_copy__parse_modules(kci, dir))
1893                 return -1;
1894
1895         if (kci->stext)
1896                 kci->stext = round_down(kci->stext, page_size);
1897         else
1898                 kci->stext = round_down(kci->first_symbol, page_size);
1899
1900         if (kci->etext) {
1901                 kci->etext = round_up(kci->etext, page_size);
1902         } else if (kci->last_symbol) {
1903                 kci->etext = round_up(kci->last_symbol, page_size);
1904                 kci->etext += page_size;
1905         }
1906
1907         if (kci->first_module_symbol &&
1908             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1909                 kci->first_module = kci->first_module_symbol;
1910
1911         kci->first_module = round_down(kci->first_module, page_size);
1912
1913         if (kci->last_module_symbol) {
1914                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1915                                                    page_size);
1916                 kci->last_module_symbol += page_size;
1917         }
1918
1919         if (!kci->stext || !kci->etext)
1920                 return -1;
1921
1922         if (kci->first_module && !kci->last_module_symbol)
1923                 return -1;
1924
1925         if (kcore_copy__read_maps(kci, elf))
1926                 return -1;
1927
1928         kcore_copy__layout(kci);
1929
1930         return 0;
1931 }
1932
1933 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1934                                  const char *name)
1935 {
1936         char from_filename[PATH_MAX];
1937         char to_filename[PATH_MAX];
1938
1939         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1940         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1941
1942         return copyfile_mode(from_filename, to_filename, 0400);
1943 }
1944
1945 static int kcore_copy__unlink(const char *dir, const char *name)
1946 {
1947         char filename[PATH_MAX];
1948
1949         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1950
1951         return unlink(filename);
1952 }
1953
1954 static int kcore_copy__compare_fds(int from, int to)
1955 {
1956         char *buf_from;
1957         char *buf_to;
1958         ssize_t ret;
1959         size_t len;
1960         int err = -1;
1961
1962         buf_from = malloc(page_size);
1963         buf_to = malloc(page_size);
1964         if (!buf_from || !buf_to)
1965                 goto out;
1966
1967         while (1) {
1968                 /* Use read because mmap won't work on proc files */
1969                 ret = read(from, buf_from, page_size);
1970                 if (ret < 0)
1971                         goto out;
1972
1973                 if (!ret)
1974                         break;
1975
1976                 len = ret;
1977
1978                 if (readn(to, buf_to, len) != (int)len)
1979                         goto out;
1980
1981                 if (memcmp(buf_from, buf_to, len))
1982                         goto out;
1983         }
1984
1985         err = 0;
1986 out:
1987         free(buf_to);
1988         free(buf_from);
1989         return err;
1990 }
1991
1992 static int kcore_copy__compare_files(const char *from_filename,
1993                                      const char *to_filename)
1994 {
1995         int from, to, err = -1;
1996
1997         from = open(from_filename, O_RDONLY);
1998         if (from < 0)
1999                 return -1;
2000
2001         to = open(to_filename, O_RDONLY);
2002         if (to < 0)
2003                 goto out_close_from;
2004
2005         err = kcore_copy__compare_fds(from, to);
2006
2007         close(to);
2008 out_close_from:
2009         close(from);
2010         return err;
2011 }
2012
2013 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2014                                     const char *name)
2015 {
2016         char from_filename[PATH_MAX];
2017         char to_filename[PATH_MAX];
2018
2019         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2020         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2021
2022         return kcore_copy__compare_files(from_filename, to_filename);
2023 }
2024
2025 /**
2026  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2027  * @from_dir: from directory
2028  * @to_dir: to directory
2029  *
2030  * This function copies kallsyms, modules and kcore files from one directory to
2031  * another.  kallsyms and modules are copied entirely.  Only code segments are
2032  * copied from kcore.  It is assumed that two segments suffice: one for the
2033  * kernel proper and one for all the modules.  The code segments are determined
2034  * from kallsyms and modules files.  The kernel map starts at _stext or the
2035  * lowest function symbol, and ends at _etext or the highest function symbol.
2036  * The module map starts at the lowest module address and ends at the highest
2037  * module symbol.  Start addresses are rounded down to the nearest page.  End
2038  * addresses are rounded up to the nearest page.  An extra page is added to the
2039  * highest kernel symbol and highest module symbol to, hopefully, encompass that
2040  * symbol too.  Because it contains only code sections, the resulting kcore is
2041  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
2042  * is not the same for the kernel map and the modules map.  That happens because
2043  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
2044  * kallsyms and modules files are compared with their copies to check that
2045  * modules have not been loaded or unloaded while the copies were taking place.
2046  *
2047  * Return: %0 on success, %-1 on failure.
2048  */
2049 int kcore_copy(const char *from_dir, const char *to_dir)
2050 {
2051         struct kcore kcore;
2052         struct kcore extract;
2053         int idx = 0, err = -1;
2054         off_t offset, sz;
2055         struct kcore_copy_info kci = { .stext = 0, };
2056         char kcore_filename[PATH_MAX];
2057         char extract_filename[PATH_MAX];
2058         struct phdr_data *p;
2059
2060         INIT_LIST_HEAD(&kci.phdrs);
2061         INIT_LIST_HEAD(&kci.syms);
2062
2063         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2064                 return -1;
2065
2066         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2067                 goto out_unlink_kallsyms;
2068
2069         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2070         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2071
2072         if (kcore__open(&kcore, kcore_filename))
2073                 goto out_unlink_modules;
2074
2075         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2076                 goto out_kcore_close;
2077
2078         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2079                 goto out_kcore_close;
2080
2081         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2082                 goto out_extract_close;
2083
2084         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2085                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2086         offset = round_up(offset, page_size);
2087
2088         kcore_copy__for_each_phdr(&kci, p) {
2089                 off_t offs = p->rel + offset;
2090
2091                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2092                         goto out_extract_close;
2093         }
2094
2095         sz = kcore__write(&extract);
2096         if (sz < 0 || sz > offset)
2097                 goto out_extract_close;
2098
2099         kcore_copy__for_each_phdr(&kci, p) {
2100                 off_t offs = p->rel + offset;
2101
2102                 if (p->remaps)
2103                         continue;
2104                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2105                         goto out_extract_close;
2106         }
2107
2108         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
2109                 goto out_extract_close;
2110
2111         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2112                 goto out_extract_close;
2113
2114         err = 0;
2115
2116 out_extract_close:
2117         kcore__close(&extract);
2118         if (err)
2119                 unlink(extract_filename);
2120 out_kcore_close:
2121         kcore__close(&kcore);
2122 out_unlink_modules:
2123         if (err)
2124                 kcore_copy__unlink(to_dir, "modules");
2125 out_unlink_kallsyms:
2126         if (err)
2127                 kcore_copy__unlink(to_dir, "kallsyms");
2128
2129         kcore_copy__free_phdrs(&kci);
2130         kcore_copy__free_syms(&kci);
2131
2132         return err;
2133 }
2134
2135 int kcore_extract__create(struct kcore_extract *kce)
2136 {
2137         struct kcore kcore;
2138         struct kcore extract;
2139         size_t count = 1;
2140         int idx = 0, err = -1;
2141         off_t offset = page_size, sz;
2142
2143         if (kcore__open(&kcore, kce->kcore_filename))
2144                 return -1;
2145
2146         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2147         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2148                 goto out_kcore_close;
2149
2150         if (kcore__copy_hdr(&kcore, &extract, count))
2151                 goto out_extract_close;
2152
2153         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2154                 goto out_extract_close;
2155
2156         sz = kcore__write(&extract);
2157         if (sz < 0 || sz > offset)
2158                 goto out_extract_close;
2159
2160         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2161                 goto out_extract_close;
2162
2163         err = 0;
2164
2165 out_extract_close:
2166         kcore__close(&extract);
2167         if (err)
2168                 unlink(kce->extract_filename);
2169 out_kcore_close:
2170         kcore__close(&kcore);
2171
2172         return err;
2173 }
2174
2175 void kcore_extract__delete(struct kcore_extract *kce)
2176 {
2177         unlink(kce->extract_filename);
2178 }
2179
2180 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2181
2182 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2183 {
2184         if (!base_off)
2185                 return;
2186
2187         if (tmp->bit32)
2188                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2189                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2190                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2191         else
2192                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2193                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2194                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2195 }
2196
2197 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2198                               GElf_Addr base_off)
2199 {
2200         if (!base_off)
2201                 return;
2202
2203         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2204                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2205         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2206                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2207 }
2208
2209 /**
2210  * populate_sdt_note : Parse raw data and identify SDT note
2211  * @elf: elf of the opened file
2212  * @data: raw data of a section with description offset applied
2213  * @len: note description size
2214  * @type: type of the note
2215  * @sdt_notes: List to add the SDT note
2216  *
2217  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2218  * if its an SDT note, it appends to @sdt_notes list.
2219  */
2220 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2221                              struct list_head *sdt_notes)
2222 {
2223         const char *provider, *name, *args;
2224         struct sdt_note *tmp = NULL;
2225         GElf_Ehdr ehdr;
2226         GElf_Shdr shdr;
2227         int ret = -EINVAL;
2228
2229         union {
2230                 Elf64_Addr a64[NR_ADDR];
2231                 Elf32_Addr a32[NR_ADDR];
2232         } buf;
2233
2234         Elf_Data dst = {
2235                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2236                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2237                 .d_off = 0, .d_align = 0
2238         };
2239         Elf_Data src = {
2240                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2241                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2242                 .d_align = 0
2243         };
2244
2245         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2246         if (!tmp) {
2247                 ret = -ENOMEM;
2248                 goto out_err;
2249         }
2250
2251         INIT_LIST_HEAD(&tmp->note_list);
2252
2253         if (len < dst.d_size + 3)
2254                 goto out_free_note;
2255
2256         /* Translation from file representation to memory representation */
2257         if (gelf_xlatetom(*elf, &dst, &src,
2258                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2259                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2260                 goto out_free_note;
2261         }
2262
2263         /* Populate the fields of sdt_note */
2264         provider = data + dst.d_size;
2265
2266         name = (const char *)memchr(provider, '\0', data + len - provider);
2267         if (name++ == NULL)
2268                 goto out_free_note;
2269
2270         tmp->provider = strdup(provider);
2271         if (!tmp->provider) {
2272                 ret = -ENOMEM;
2273                 goto out_free_note;
2274         }
2275         tmp->name = strdup(name);
2276         if (!tmp->name) {
2277                 ret = -ENOMEM;
2278                 goto out_free_prov;
2279         }
2280
2281         args = memchr(name, '\0', data + len - name);
2282
2283         /*
2284          * There is no argument if:
2285          * - We reached the end of the note;
2286          * - There is not enough room to hold a potential string;
2287          * - The argument string is empty or just contains ':'.
2288          */
2289         if (args == NULL || data + len - args < 2 ||
2290                 args[1] == ':' || args[1] == '\0')
2291                 tmp->args = NULL;
2292         else {
2293                 tmp->args = strdup(++args);
2294                 if (!tmp->args) {
2295                         ret = -ENOMEM;
2296                         goto out_free_name;
2297                 }
2298         }
2299
2300         if (gelf_getclass(*elf) == ELFCLASS32) {
2301                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2302                 tmp->bit32 = true;
2303         } else {
2304                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2305                 tmp->bit32 = false;
2306         }
2307
2308         if (!gelf_getehdr(*elf, &ehdr)) {
2309                 pr_debug("%s : cannot get elf header.\n", __func__);
2310                 ret = -EBADF;
2311                 goto out_free_args;
2312         }
2313
2314         /* Adjust the prelink effect :
2315          * Find out the .stapsdt.base section.
2316          * This scn will help us to handle prelinking (if present).
2317          * Compare the retrieved file offset of the base section with the
2318          * base address in the description of the SDT note. If its different,
2319          * then accordingly, adjust the note location.
2320          */
2321         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2322                 sdt_adjust_loc(tmp, shdr.sh_offset);
2323
2324         /* Adjust reference counter offset */
2325         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2326                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2327
2328         list_add_tail(&tmp->note_list, sdt_notes);
2329         return 0;
2330
2331 out_free_args:
2332         zfree(&tmp->args);
2333 out_free_name:
2334         zfree(&tmp->name);
2335 out_free_prov:
2336         zfree(&tmp->provider);
2337 out_free_note:
2338         free(tmp);
2339 out_err:
2340         return ret;
2341 }
2342
2343 /**
2344  * construct_sdt_notes_list : constructs a list of SDT notes
2345  * @elf : elf to look into
2346  * @sdt_notes : empty list_head
2347  *
2348  * Scans the sections in 'elf' for the section
2349  * .note.stapsdt. It, then calls populate_sdt_note to find
2350  * out the SDT events and populates the 'sdt_notes'.
2351  */
2352 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2353 {
2354         GElf_Ehdr ehdr;
2355         Elf_Scn *scn = NULL;
2356         Elf_Data *data;
2357         GElf_Shdr shdr;
2358         size_t shstrndx, next;
2359         GElf_Nhdr nhdr;
2360         size_t name_off, desc_off, offset;
2361         int ret = 0;
2362
2363         if (gelf_getehdr(elf, &ehdr) == NULL) {
2364                 ret = -EBADF;
2365                 goto out_ret;
2366         }
2367         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2368                 ret = -EBADF;
2369                 goto out_ret;
2370         }
2371
2372         /* Look for the required section */
2373         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2374         if (!scn) {
2375                 ret = -ENOENT;
2376                 goto out_ret;
2377         }
2378
2379         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2380                 ret = -ENOENT;
2381                 goto out_ret;
2382         }
2383
2384         data = elf_getdata(scn, NULL);
2385
2386         /* Get the SDT notes */
2387         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2388                                               &desc_off)) > 0; offset = next) {
2389                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2390                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2391                             sizeof(SDT_NOTE_NAME))) {
2392                         /* Check the type of the note */
2393                         if (nhdr.n_type != SDT_NOTE_TYPE)
2394                                 goto out_ret;
2395
2396                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2397                                                 nhdr.n_descsz, sdt_notes);
2398                         if (ret < 0)
2399                                 goto out_ret;
2400                 }
2401         }
2402         if (list_empty(sdt_notes))
2403                 ret = -ENOENT;
2404
2405 out_ret:
2406         return ret;
2407 }
2408
2409 /**
2410  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2411  * @head : empty list_head
2412  * @target : file to find SDT notes from
2413  *
2414  * This opens the file, initializes
2415  * the ELF and then calls construct_sdt_notes_list.
2416  */
2417 int get_sdt_note_list(struct list_head *head, const char *target)
2418 {
2419         Elf *elf;
2420         int fd, ret;
2421
2422         fd = open(target, O_RDONLY);
2423         if (fd < 0)
2424                 return -EBADF;
2425
2426         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2427         if (!elf) {
2428                 ret = -EBADF;
2429                 goto out_close;
2430         }
2431         ret = construct_sdt_notes_list(elf, head);
2432         elf_end(elf);
2433 out_close:
2434         close(fd);
2435         return ret;
2436 }
2437
2438 /**
2439  * cleanup_sdt_note_list : free the sdt notes' list
2440  * @sdt_notes: sdt notes' list
2441  *
2442  * Free up the SDT notes in @sdt_notes.
2443  * Returns the number of SDT notes free'd.
2444  */
2445 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2446 {
2447         struct sdt_note *tmp, *pos;
2448         int nr_free = 0;
2449
2450         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2451                 list_del_init(&pos->note_list);
2452                 zfree(&pos->args);
2453                 zfree(&pos->name);
2454                 zfree(&pos->provider);
2455                 free(pos);
2456                 nr_free++;
2457         }
2458         return nr_free;
2459 }
2460
2461 /**
2462  * sdt_notes__get_count: Counts the number of sdt events
2463  * @start: list_head to sdt_notes list
2464  *
2465  * Returns the number of SDT notes in a list
2466  */
2467 int sdt_notes__get_count(struct list_head *start)
2468 {
2469         struct sdt_note *sdt_ptr;
2470         int count = 0;
2471
2472         list_for_each_entry(sdt_ptr, start, note_list)
2473                 count++;
2474         return count;
2475 }
2476 #endif
2477
2478 void symbol__elf_init(void)
2479 {
2480         elf_version(EV_CURRENT);
2481 }