tools/perf/util/symbol-elf.c

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