root/tools/perf/util/symbol-elf.c

DEFINITIONS

1. bfd_demangle
2. bfd_demangle
3. elf_getphdrnum
4. elf_getshdrstrndx
5. elf_sym__type
6. elf_sym__visibility
7. elf_sym__is_function
8. elf_sym__is_object
9. elf_sym__is_label
10. elf_sym__filter
11. elf_sym__name
12. elf_sec__name
13. elf_sec__is_text
14. elf_sec__is_data
15. elf_sec__filter
16. elf_addr_to_index
17. elf_section_by_name
18. want_demangle
19. demangle_sym
20. dso__synthesize_plt_symbols
21. dso__demangle_sym
22. elf_read_build_id
23. filename__read_build_id
24. sysfs__read_build_id
25. filename__read_debuglink
26. dso__swap_init
27. symsrc__possibly_runtime
28. symsrc__has_symtab
29. symsrc__destroy
30. elf__needs_adjust_symbols
31. symsrc__init
32. ref_reloc_sym_not_found
33. ref_reloc
34. arch__sym_update
35. dso__process_kernel_symbol
36. dso__load_sym
37. elf_read_maps
38. file__read_maps
39. dso__type_fd
40. copy_bytes
41. kcore__open
42. kcore__init
43. kcore__close
44. kcore__copy_hdr
45. kcore__add_phdr
46. kcore__write
47. phdr_data__new
48. kcore_copy_info__addnew
49. kcore_copy__free_phdrs
50. kcore_copy__new_sym
51. kcore_copy__free_syms
52. kcore_copy__process_kallsyms
53. kcore_copy__parse_kallsyms
54. kcore_copy__process_modules
55. kcore_copy__parse_modules
56. kcore_copy__map
57. kcore_copy__read_map
58. kcore_copy__read_maps
59. kcore_copy__find_remaps
60. kcore_copy__layout
61. kcore_copy__calc_maps
62. kcore_copy__copy_file
63. kcore_copy__unlink
64. kcore_copy__compare_fds
65. kcore_copy__compare_files
66. kcore_copy__compare_file
67. kcore_copy
68. kcore_extract__create
69. kcore_extract__delete
70. sdt_adjust_loc
71. sdt_adjust_refctr
72. populate_sdt_note
73. construct_sdt_notes_list
74. get_sdt_note_list
75. cleanup_sdt_note_list
76. sdt_notes__get_count
77. symbol__elf_init

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