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