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