tools/perf/util/symbol-elf.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <errno.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <inttypes.h>
   9
  10 #include "dso.h"
  11 #include "map.h"
  12 #include "maps.h"
  13 #include "symbol.h"
  14 #include "symsrc.h"
  15 #include "demangle-java.h"
  16 #include "demangle-rust.h"
  17 #include "machine.h"
  18 #include "vdso.h"
  19 #include "debug.h"
  20 #include "util/copyfile.h"
  21 #include <linux/ctype.h>
  22 #include <linux/kernel.h>
  23 #include <linux/zalloc.h>
  24 #include <symbol/kallsyms.h>
  25 #include <internal/lib.h>
  26
  27 #ifndef EM_AARCH64
  28 #define EM_AARCH64      183  /* ARM 64 bit */
  29 #endif
  30
  31 #ifndef ELF32_ST_VISIBILITY
  32 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  33 #endif
  34
  35 /* For ELF64 the definitions are the same.  */
  36 #ifndef ELF64_ST_VISIBILITY
  37 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  38 #endif
  39
  40 /* How to extract information held in the st_other field.  */
  41 #ifndef GELF_ST_VISIBILITY
  42 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  43 #endif
  44
  45 typedef Elf64_Nhdr GElf_Nhdr;
  46
  47 #ifndef DMGL_PARAMS
  48 #define DMGL_NO_OPTS     0              /* For readability... */
  49 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  50 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  51 #endif
  52
  53 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  54 extern char *cplus_demangle(const char *, int);
  55
  56 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  57 {
  58         return cplus_demangle(c, i);
  59 }
  60 #else
  61 #ifdef NO_DEMANGLE
  62 static inline char *bfd_demangle(void __maybe_unused *v,
  63                                  const char __maybe_unused *c,
  64                                  int __maybe_unused i)
  65 {
  66         return NULL;
  67 }
  68 #else
  69 #define PACKAGE 'perf'
  70 #include <bfd.h>
  71 #endif
  72 #endif
  73
  74 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  75 static int elf_getphdrnum(Elf *elf, size_t *dst)
  76 {
  77         GElf_Ehdr gehdr;
  78         GElf_Ehdr *ehdr;
  79
  80         ehdr = gelf_getehdr(elf, &gehdr);
  81         if (!ehdr)
  82                 return -1;
  83
  84         *dst = ehdr->e_phnum;
  85
  86         return 0;
  87 }
  88 #endif
  89
  90 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  91 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  92 {
  93         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  94         return -1;
  95 }
  96 #endif
  97
  98 #ifndef NT_GNU_BUILD_ID
  99 #define NT_GNU_BUILD_ID 3
 100 #endif
 101
 102 /**
 103  * elf_symtab__for_each_symbol - iterate thru all the symbols
 104  *
 105  * @syms: struct elf_symtab instance to iterate
 106  * @idx: uint32_t idx
 107  * @sym: GElf_Sym iterator
 108  */
 109 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 110         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 111              idx < nr_syms; \
 112              idx++, gelf_getsym(syms, idx, &sym))
 113
 114 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 115 {
 116         return GELF_ST_TYPE(sym->st_info);
 117 }
 118
 119 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 120 {
 121         return GELF_ST_VISIBILITY(sym->st_other);
 122 }
 123
 124 #ifndef STT_GNU_IFUNC
 125 #define STT_GNU_IFUNC 10
 126 #endif
 127
 128 static inline int elf_sym__is_function(const GElf_Sym *sym)
 129 {
 130         return (elf_sym__type(sym) == STT_FUNC ||
 131                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 132                sym->st_name != 0 &&
 133                sym->st_shndx != SHN_UNDEF;
 134 }
 135
 136 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 137 {
 138         return elf_sym__type(sym) == STT_OBJECT &&
 139                 sym->st_name != 0 &&
 140                 sym->st_shndx != SHN_UNDEF;
 141 }
 142
 143 static inline int elf_sym__is_label(const GElf_Sym *sym)
 144 {
 145         return elf_sym__type(sym) == STT_NOTYPE &&
 146                 sym->st_name != 0 &&
 147                 sym->st_shndx != SHN_UNDEF &&
 148                 sym->st_shndx != SHN_ABS &&
 149                 elf_sym__visibility(sym) != STV_HIDDEN &&
 150                 elf_sym__visibility(sym) != STV_INTERNAL;
 151 }
 152
 153 static bool elf_sym__filter(GElf_Sym *sym)
 154 {
 155         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 156 }
 157
 158 static inline const char *elf_sym__name(const GElf_Sym *sym,
 159                                         const Elf_Data *symstrs)
 160 {
 161         return symstrs->d_buf + sym->st_name;
 162 }
 163
 164 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 165                                         const Elf_Data *secstrs)
 166 {
 167         return secstrs->d_buf + shdr->sh_name;
 168 }
 169
 170 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 171                                         const Elf_Data *secstrs)
 172 {
 173         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 174 }
 175
 176 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 177                                     const Elf_Data *secstrs)
 178 {
 179         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 180 }
 181
 182 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 183 {
 184         return elf_sec__is_text(shdr, secstrs) ||
 185                elf_sec__is_data(shdr, secstrs);
 186 }
 187
 188 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 189 {
 190         Elf_Scn *sec = NULL;
 191         GElf_Shdr shdr;
 192         size_t cnt = 1;
 193
 194         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 195                 gelf_getshdr(sec, &shdr);
 196
 197                 if ((addr >= shdr.sh_addr) &&
 198                     (addr < (shdr.sh_addr + shdr.sh_size)))
 199                         return cnt;
 200
 201                 ++cnt;
 202         }
 203
 204         return -1;
 205 }
 206
 207 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 208                              GElf_Shdr *shp, const char *name, size_t *idx)
 209 {
 210         Elf_Scn *sec = NULL;
 211         size_t cnt = 1;
 212
 213         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 214         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 215                 return NULL;
 216
 217         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 218                 char *str;
 219
 220                 gelf_getshdr(sec, shp);
 221                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 222                 if (str && !strcmp(name, str)) {
 223                         if (idx)
 224                                 *idx = cnt;
 225                         return sec;
 226                 }
 227                 ++cnt;
 228         }
 229
 230         return NULL;
 231 }
 232
 233 static bool want_demangle(bool is_kernel_sym)
 234 {
 235         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 236 }
 237
 238 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 239 {
 240         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 241         char *demangled = NULL;
 242
 243         /*
 244          * We need to figure out if the object was created from C++ sources
 245          * DWARF DW_compile_unit has this, but we don't always have access
 246          * to it...
 247          */
 248         if (!want_demangle(dso->kernel || kmodule))
 249             return demangled;
 250
 251         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 252         if (demangled == NULL)
 253                 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 254         else if (rust_is_mangled(demangled))
 255                 /*
 256                     * Input to Rust demangling is the BFD-demangled
 257                     * name which it Rust-demangles in place.
 258                     */
 259                 rust_demangle_sym(demangled);
 260
 261         return demangled;
 262 }
 263
 264 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 265         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 266              idx < nr_entries; \
 267              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 268
 269 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 270         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 271              idx < nr_entries; \
 272              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 273
 274 /*
 275  * We need to check if we have a .dynsym, so that we can handle the
 276  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 277  * .dynsym or .symtab).
 278  * And always look at the original dso, not at debuginfo packages, that
 279  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 280  */
 281 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 282 {
 283         uint32_t nr_rel_entries, idx;
 284         GElf_Sym sym;
 285         u64 plt_offset, plt_header_size, plt_entry_size;
 286         GElf_Shdr shdr_plt;
 287         struct symbol *f;
 288         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 289         Elf_Data *reldata, *syms, *symstrs;
 290         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 291         size_t dynsym_idx;
 292         GElf_Ehdr ehdr;
 293         char sympltname[1024];
 294         Elf *elf;
 295         int nr = 0, symidx, err = 0;
 296
 297         if (!ss->dynsym)
 298                 return 0;
 299
 300         elf = ss->elf;
 301         ehdr = ss->ehdr;
 302
 303         scn_dynsym = ss->dynsym;
 304         shdr_dynsym = ss->dynshdr;
 305         dynsym_idx = ss->dynsym_idx;
 306
 307         if (scn_dynsym == NULL)
 308                 goto out_elf_end;
 309
 310         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 311                                           ".rela.plt", NULL);
 312         if (scn_plt_rel == NULL) {
 313                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 314                                                   ".rel.plt", NULL);
 315                 if (scn_plt_rel == NULL)
 316                         goto out_elf_end;
 317         }
 318
 319         err = -1;
 320
 321         if (shdr_rel_plt.sh_link != dynsym_idx)
 322                 goto out_elf_end;
 323
 324         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 325                 goto out_elf_end;
 326
 327         /*
 328          * Fetch the relocation section to find the idxes to the GOT
 329          * and the symbols in the .dynsym they refer to.
 330          */
 331         reldata = elf_getdata(scn_plt_rel, NULL);
 332         if (reldata == NULL)
 333                 goto out_elf_end;
 334
 335         syms = elf_getdata(scn_dynsym, NULL);
 336         if (syms == NULL)
 337                 goto out_elf_end;
 338
 339         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 340         if (scn_symstrs == NULL)
 341                 goto out_elf_end;
 342
 343         symstrs = elf_getdata(scn_symstrs, NULL);
 344         if (symstrs == NULL)
 345                 goto out_elf_end;
 346
 347         if (symstrs->d_size == 0)
 348                 goto out_elf_end;
 349
 350         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 351         plt_offset = shdr_plt.sh_offset;
 352         switch (ehdr.e_machine) {
 353                 case EM_ARM:
 354                         plt_header_size = 20;
 355                         plt_entry_size = 12;
 356                         break;
 357
 358                 case EM_AARCH64:
 359                         plt_header_size = 32;
 360                         plt_entry_size = 16;
 361                         break;
 362
 363                 case EM_SPARC:
 364                         plt_header_size = 48;
 365                         plt_entry_size = 12;
 366                         break;
 367
 368                 case EM_SPARCV9:
 369                         plt_header_size = 128;
 370                         plt_entry_size = 32;
 371                         break;
 372
 373                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 374                         plt_header_size = shdr_plt.sh_entsize;
 375                         plt_entry_size = shdr_plt.sh_entsize;
 376                         break;
 377         }
 378         plt_offset += plt_header_size;
 379
 380         if (shdr_rel_plt.sh_type == SHT_RELA) {
 381                 GElf_Rela pos_mem, *pos;
 382
 383                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 384                                            nr_rel_entries) {
 385                         const char *elf_name = NULL;
 386                         char *demangled = NULL;
 387                         symidx = GELF_R_SYM(pos->r_info);
 388                         gelf_getsym(syms, symidx, &sym);
 389
 390                         elf_name = elf_sym__name(&sym, symstrs);
 391                         demangled = demangle_sym(dso, 0, elf_name);
 392                         if (demangled != NULL)
 393                                 elf_name = demangled;
 394                         snprintf(sympltname, sizeof(sympltname),
 395                                  "%s@plt", elf_name);
 396                         free(demangled);
 397
 398                         f = symbol__new(plt_offset, plt_entry_size,
 399                                         STB_GLOBAL, STT_FUNC, sympltname);
 400                         if (!f)
 401                                 goto out_elf_end;
 402
 403                         plt_offset += plt_entry_size;
 404                         symbols__insert(&dso->symbols, f);
 405                         ++nr;
 406                 }
 407         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 408                 GElf_Rel pos_mem, *pos;
 409                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 410                                           nr_rel_entries) {
 411                         const char *elf_name = NULL;
 412                         char *demangled = NULL;
 413                         symidx = GELF_R_SYM(pos->r_info);
 414                         gelf_getsym(syms, symidx, &sym);
 415
 416                         elf_name = elf_sym__name(&sym, symstrs);
 417                         demangled = demangle_sym(dso, 0, elf_name);
 418                         if (demangled != NULL)
 419                                 elf_name = demangled;
 420                         snprintf(sympltname, sizeof(sympltname),
 421                                  "%s@plt", elf_name);
 422                         free(demangled);
 423
 424                         f = symbol__new(plt_offset, plt_entry_size,
 425                                         STB_GLOBAL, STT_FUNC, sympltname);
 426                         if (!f)
 427                                 goto out_elf_end;
 428
 429                         plt_offset += plt_entry_size;
 430                         symbols__insert(&dso->symbols, f);
 431                         ++nr;
 432                 }
 433         }
 434
 435         err = 0;
 436 out_elf_end:
 437         if (err == 0)
 438                 return nr;
 439         pr_debug("%s: problems reading %s PLT info.\n",
 440                  __func__, dso->long_name);
 441         return 0;
 442 }
 443
 444 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 445 {
 446         return demangle_sym(dso, kmodule, elf_name);
 447 }
 448
 449 /*
 450  * Align offset to 4 bytes as needed for note name and descriptor data.
 451  */
 452 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 453
 454 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 455 {
 456         int err = -1;
 457         GElf_Ehdr ehdr;
 458         GElf_Shdr shdr;
 459         Elf_Data *data;
 460         Elf_Scn *sec;
 461         Elf_Kind ek;
 462         void *ptr;
 463
 464         if (size < BUILD_ID_SIZE)
 465                 goto out;
 466
 467         ek = elf_kind(elf);
 468         if (ek != ELF_K_ELF)
 469                 goto out;
 470
 471         if (gelf_getehdr(elf, &ehdr) == NULL) {
 472                 pr_err("%s: cannot get elf header.\n", __func__);
 473                 goto out;
 474         }
 475
 476         /*
 477          * Check following sections for notes:
 478          *   '.note.gnu.build-id'
 479          *   '.notes'
 480          *   '.note' (VDSO specific)
 481          */
 482         do {
 483                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 484                                           ".note.gnu.build-id", NULL);
 485                 if (sec)
 486                         break;
 487
 488                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 489                                           ".notes", NULL);
 490                 if (sec)
 491                         break;
 492
 493                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 494                                           ".note", NULL);
 495                 if (sec)
 496                         break;
 497
 498                 return err;
 499
 500         } while (0);
 501
 502         data = elf_getdata(sec, NULL);
 503         if (data == NULL)
 504                 goto out;
 505
 506         ptr = data->d_buf;
 507         while (ptr < (data->d_buf + data->d_size)) {
 508                 GElf_Nhdr *nhdr = ptr;
 509                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 510                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 511                 const char *name;
 512
 513                 ptr += sizeof(*nhdr);
 514                 name = ptr;
 515                 ptr += namesz;
 516                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 517                     nhdr->n_namesz == sizeof("GNU")) {
 518                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 519                                 size_t sz = min(size, descsz);
 520                                 memcpy(bf, ptr, sz);
 521                                 memset(bf + sz, 0, size - sz);
 522                                 err = descsz;
 523                                 break;
 524                         }
 525                 }
 526                 ptr += descsz;
 527         }
 528
 529 out:
 530         return err;
 531 }
 532
 533 int filename__read_build_id(const char *filename, void *bf, size_t size)
 534 {
 535         int fd, err = -1;
 536         Elf *elf;
 537
 538         if (size < BUILD_ID_SIZE)
 539                 goto out;
 540
 541         fd = open(filename, O_RDONLY);
 542         if (fd < 0)
 543                 goto out;
 544
 545         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 546         if (elf == NULL) {
 547                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 548                 goto out_close;
 549         }
 550
 551         err = elf_read_build_id(elf, bf, size);
 552
 553         elf_end(elf);
 554 out_close:
 555         close(fd);
 556 out:
 557         return err;
 558 }
 559
 560 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 561 {
 562         int fd, err = -1;
 563
 564         if (size < BUILD_ID_SIZE)
 565                 goto out;
 566
 567         fd = open(filename, O_RDONLY);
 568         if (fd < 0)
 569                 goto out;
 570
 571         while (1) {
 572                 char bf[BUFSIZ];
 573                 GElf_Nhdr nhdr;
 574                 size_t namesz, descsz;
 575
 576                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 577                         break;
 578
 579                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 580                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 581                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 582                     nhdr.n_namesz == sizeof("GNU")) {
 583                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 584                                 break;
 585                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 586                                 size_t sz = min(descsz, size);
 587                                 if (read(fd, build_id, sz) == (ssize_t)sz) {
 588                                         memset(build_id + sz, 0, size - sz);
 589                                         err = 0;
 590                                         break;
 591                                 }
 592                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 593                                 break;
 594                 } else {
 595                         int n = namesz + descsz;
 596
 597                         if (n > (int)sizeof(bf)) {
 598                                 n = sizeof(bf);
 599                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 600                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 601                         }
 602                         if (read(fd, bf, n) != n)
 603                                 break;
 604                 }
 605         }
 606         close(fd);
 607 out:
 608         return err;
 609 }
 610
 611 int filename__read_debuglink(const char *filename, char *debuglink,
 612                              size_t size)
 613 {
 614         int fd, err = -1;
 615         Elf *elf;
 616         GElf_Ehdr ehdr;
 617         GElf_Shdr shdr;
 618         Elf_Data *data;
 619         Elf_Scn *sec;
 620         Elf_Kind ek;
 621
 622         fd = open(filename, O_RDONLY);
 623         if (fd < 0)
 624                 goto out;
 625
 626         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 627         if (elf == NULL) {
 628                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 629                 goto out_close;
 630         }
 631
 632         ek = elf_kind(elf);
 633         if (ek != ELF_K_ELF)
 634                 goto out_elf_end;
 635
 636         if (gelf_getehdr(elf, &ehdr) == NULL) {
 637                 pr_err("%s: cannot get elf header.\n", __func__);
 638                 goto out_elf_end;
 639         }
 640
 641         sec = elf_section_by_name(elf, &ehdr, &shdr,
 642                                   ".gnu_debuglink", NULL);
 643         if (sec == NULL)
 644                 goto out_elf_end;
 645
 646         data = elf_getdata(sec, NULL);
 647         if (data == NULL)
 648                 goto out_elf_end;
 649
 650         /* the start of this section is a zero-terminated string */
 651         strncpy(debuglink, data->d_buf, size);
 652
 653         err = 0;
 654
 655 out_elf_end:
 656         elf_end(elf);
 657 out_close:
 658         close(fd);
 659 out:
 660         return err;
 661 }
 662
 663 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 664 {
 665         static unsigned int const endian = 1;
 666
 667         dso->needs_swap = DSO_SWAP__NO;
 668
 669         switch (eidata) {
 670         case ELFDATA2LSB:
 671                 /* We are big endian, DSO is little endian. */
 672                 if (*(unsigned char const *)&endian != 1)
 673                         dso->needs_swap = DSO_SWAP__YES;
 674                 break;
 675
 676         case ELFDATA2MSB:
 677                 /* We are little endian, DSO is big endian. */
 678                 if (*(unsigned char const *)&endian != 0)
 679                         dso->needs_swap = DSO_SWAP__YES;
 680                 break;
 681
 682         default:
 683                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 684                 return -EINVAL;
 685         }
 686
 687         return 0;
 688 }
 689
 690 bool symsrc__possibly_runtime(struct symsrc *ss)
 691 {
 692         return ss->dynsym || ss->opdsec;
 693 }
 694
 695 bool symsrc__has_symtab(struct symsrc *ss)
 696 {
 697         return ss->symtab != NULL;
 698 }
 699
 700 void symsrc__destroy(struct symsrc *ss)
 701 {
 702         zfree(&ss->name);
 703         elf_end(ss->elf);
 704         close(ss->fd);
 705 }
 706
 707 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 708 {
 709         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
 710 }
 711
 712 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 713                  enum dso_binary_type type)
 714 {
 715         GElf_Ehdr ehdr;
 716         Elf *elf;
 717         int fd;
 718
 719         if (dso__needs_decompress(dso)) {
 720                 fd = dso__decompress_kmodule_fd(dso, name);
 721                 if (fd < 0)
 722                         return -1;
 723
 724                 type = dso->symtab_type;
 725         } else {
 726                 fd = open(name, O_RDONLY);
 727                 if (fd < 0) {
 728                         dso->load_errno = errno;
 729                         return -1;
 730                 }
 731         }
 732
 733         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 734         if (elf == NULL) {
 735                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 736                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 737                 goto out_close;
 738         }
 739
 740         if (gelf_getehdr(elf, &ehdr) == NULL) {
 741                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 742                 pr_debug("%s: cannot get elf header.\n", __func__);
 743                 goto out_elf_end;
 744         }
 745
 746         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 747                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 748                 goto out_elf_end;
 749         }
 750
 751         /* Always reject images with a mismatched build-id: */
 752         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 753                 u8 build_id[BUILD_ID_SIZE];
 754
 755                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 756                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 757                         goto out_elf_end;
 758                 }
 759
 760                 if (!dso__build_id_equal(dso, build_id)) {
 761                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 762                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 763                         goto out_elf_end;
 764                 }
 765         }
 766
 767         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 768
 769         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 770                         NULL);
 771         if (ss->symshdr.sh_type != SHT_SYMTAB)
 772                 ss->symtab = NULL;
 773
 774         ss->dynsym_idx = 0;
 775         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 776                         &ss->dynsym_idx);
 777         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 778                 ss->dynsym = NULL;
 779
 780         ss->opdidx = 0;
 781         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 782                         &ss->opdidx);
 783         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 784                 ss->opdsec = NULL;
 785
 786         if (dso->kernel == DSO_TYPE_USER)
 787                 ss->adjust_symbols = true;
 788         else
 789                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 790
 791         ss->name   = strdup(name);
 792         if (!ss->name) {
 793                 dso->load_errno = errno;
 794                 goto out_elf_end;
 795         }
 796
 797         ss->elf    = elf;
 798         ss->fd     = fd;
 799         ss->ehdr   = ehdr;
 800         ss->type   = type;
 801
 802         return 0;
 803
 804 out_elf_end:
 805         elf_end(elf);
 806 out_close:
 807         close(fd);
 808         return -1;
 809 }
 810
 811 /**
 812  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 813  * @kmap: kernel maps and relocation reference symbol
 814  *
 815  * This function returns %true if we are dealing with the kernel maps and the
 816  * relocation reference symbol has not yet been found.  Otherwise %false is
 817  * returned.
 818  */
 819 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 820 {
 821         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 822                !kmap->ref_reloc_sym->unrelocated_addr;
 823 }
 824
 825 /**
 826  * ref_reloc - kernel relocation offset.
 827  * @kmap: kernel maps and relocation reference symbol
 828  *
 829  * This function returns the offset of kernel addresses as determined by using
 830  * the relocation reference symbol i.e. if the kernel has not been relocated
 831  * then the return value is zero.
 832  */
 833 static u64 ref_reloc(struct kmap *kmap)
 834 {
 835         if (kmap && kmap->ref_reloc_sym &&
 836             kmap->ref_reloc_sym->unrelocated_addr)
 837                 return kmap->ref_reloc_sym->addr -
 838                        kmap->ref_reloc_sym->unrelocated_addr;
 839         return 0;
 840 }
 841
 842 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 843                 GElf_Sym *sym __maybe_unused) { }
 844
 845 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 846                                       GElf_Sym *sym, GElf_Shdr *shdr,
 847                                       struct maps *kmaps, struct kmap *kmap,
 848                                       struct dso **curr_dsop, struct map **curr_mapp,
 849                                       const char *section_name,
 850                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 851 {
 852         struct dso *curr_dso = *curr_dsop;
 853         struct map *curr_map;
 854         char dso_name[PATH_MAX];
 855
 856         /* Adjust symbol to map to file offset */
 857         if (adjust_kernel_syms)
 858                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 859
 860         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 861                 return 0;
 862
 863         if (strcmp(section_name, ".text") == 0) {
 864                 /*
 865                  * The initial kernel mapping is based on
 866                  * kallsyms and identity maps.  Overwrite it to
 867                  * map to the kernel dso.
 868                  */
 869                 if (*remap_kernel && dso->kernel) {
 870                         *remap_kernel = false;
 871                         map->start = shdr->sh_addr + ref_reloc(kmap);
 872                         map->end = map->start + shdr->sh_size;
 873                         map->pgoff = shdr->sh_offset;
 874                         map->map_ip = map__map_ip;
 875                         map->unmap_ip = map__unmap_ip;
 876                         /* Ensure maps are correctly ordered */
 877                         if (kmaps) {
 878                                 map__get(map);
 879                                 maps__remove(kmaps, map);
 880                                 maps__insert(kmaps, map);
 881                                 map__put(map);
 882                         }
 883                 }
 884
 885                 /*
 886                  * The initial module mapping is based on
 887                  * /proc/modules mapped to offset zero.
 888                  * Overwrite it to map to the module dso.
 889                  */
 890                 if (*remap_kernel && kmodule) {
 891                         *remap_kernel = false;
 892                         map->pgoff = shdr->sh_offset;
 893                 }
 894
 895                 *curr_mapp = map;
 896                 *curr_dsop = dso;
 897                 return 0;
 898         }
 899
 900         if (!kmap)
 901                 return 0;
 902
 903         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 904
 905         curr_map = maps__find_by_name(kmaps, dso_name);
 906         if (curr_map == NULL) {
 907                 u64 start = sym->st_value;
 908
 909                 if (kmodule)
 910                         start += map->start + shdr->sh_offset;
 911
 912                 curr_dso = dso__new(dso_name);
 913                 if (curr_dso == NULL)
 914                         return -1;
 915                 curr_dso->kernel = dso->kernel;
 916                 curr_dso->long_name = dso->long_name;
 917                 curr_dso->long_name_len = dso->long_name_len;
 918                 curr_map = map__new2(start, curr_dso);
 919                 dso__put(curr_dso);
 920                 if (curr_map == NULL)
 921                         return -1;
 922
 923                 if (curr_dso->kernel)
 924                         map__kmap(curr_map)->kmaps = kmaps;
 925
 926                 if (adjust_kernel_syms) {
 927                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 928                         curr_map->end    = curr_map->start + shdr->sh_size;
 929                         curr_map->pgoff  = shdr->sh_offset;
 930                 } else {
 931                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 932                 }
 933                 curr_dso->symtab_type = dso->symtab_type;
 934                 maps__insert(kmaps, curr_map);
 935                 /*
 936                  * Add it before we drop the referece to curr_map, i.e. while
 937                  * we still are sure to have a reference to this DSO via
 938                  * *curr_map->dso.
 939                  */
 940                 dsos__add(&kmaps->machine->dsos, curr_dso);
 941                 /* kmaps already got it */
 942                 map__put(curr_map);
 943                 dso__set_loaded(curr_dso);
 944                 *curr_mapp = curr_map;
 945                 *curr_dsop = curr_dso;
 946         } else
 947                 *curr_dsop = curr_map->dso;
 948
 949         return 0;
 950 }
 951
 952 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 953                   struct symsrc *runtime_ss, int kmodule)
 954 {
 955         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 956         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
 957         struct map *curr_map = map;
 958         struct dso *curr_dso = dso;
 959         Elf_Data *symstrs, *secstrs;
 960         uint32_t nr_syms;
 961         int err = -1;
 962         uint32_t idx;
 963         GElf_Ehdr ehdr;
 964         GElf_Shdr shdr;
 965         GElf_Shdr tshdr;
 966         Elf_Data *syms, *opddata = NULL;
 967         GElf_Sym sym;
 968         Elf_Scn *sec, *sec_strndx;
 969         Elf *elf;
 970         int nr = 0;
 971         bool remap_kernel = false, adjust_kernel_syms = false;
 972
 973         if (kmap && !kmaps)
 974                 return -1;
 975
 976         dso->symtab_type = syms_ss->type;
 977         dso->is_64_bit = syms_ss->is_64_bit;
 978         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 979
 980         /*
 981          * Modules may already have symbols from kallsyms, but those symbols
 982          * have the wrong values for the dso maps, so remove them.
 983          */
 984         if (kmodule && syms_ss->symtab)
 985                 symbols__delete(&dso->symbols);
 986
 987         if (!syms_ss->symtab) {
 988                 /*
 989                  * If the vmlinux is stripped, fail so we will fall back
 990                  * to using kallsyms. The vmlinux runtime symbols aren't
 991                  * of much use.
 992                  */
 993                 if (dso->kernel)
 994                         goto out_elf_end;
 995
 996                 syms_ss->symtab  = syms_ss->dynsym;
 997                 syms_ss->symshdr = syms_ss->dynshdr;
 998         }
 999
1000         elf = syms_ss->elf;
1001         ehdr = syms_ss->ehdr;
1002         sec = syms_ss->symtab;
1003         shdr = syms_ss->symshdr;
1004
1005         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1006                                 ".text", NULL))
1007                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1008
1009         if (runtime_ss->opdsec)
1010                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1011
1012         syms = elf_getdata(sec, NULL);
1013         if (syms == NULL)
1014                 goto out_elf_end;
1015
1016         sec = elf_getscn(elf, shdr.sh_link);
1017         if (sec == NULL)
1018                 goto out_elf_end;
1019
1020         symstrs = elf_getdata(sec, NULL);
1021         if (symstrs == NULL)
1022                 goto out_elf_end;
1023
1024         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1025         if (sec_strndx == NULL)
1026                 goto out_elf_end;
1027
1028         secstrs = elf_getdata(sec_strndx, NULL);
1029         if (secstrs == NULL)
1030                 goto out_elf_end;
1031
1032         nr_syms = shdr.sh_size / shdr.sh_entsize;
1033
1034         memset(&sym, 0, sizeof(sym));
1035
1036         /*
1037          * The kernel relocation symbol is needed in advance in order to adjust
1038          * kernel maps correctly.
1039          */
1040         if (ref_reloc_sym_not_found(kmap)) {
1041                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1042                         const char *elf_name = elf_sym__name(&sym, symstrs);
1043
1044                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1045                                 continue;
1046                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1047                         map->reloc = kmap->ref_reloc_sym->addr -
1048                                      kmap->ref_reloc_sym->unrelocated_addr;
1049                         break;
1050                 }
1051         }
1052
1053         /*
1054          * Handle any relocation of vdso necessary because older kernels
1055          * attempted to prelink vdso to its virtual address.
1056          */
1057         if (dso__is_vdso(dso))
1058                 map->reloc = map->start - dso->text_offset;
1059
1060         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1061         /*
1062          * Initial kernel and module mappings do not map to the dso.
1063          * Flag the fixups.
1064          */
1065         if (dso->kernel || kmodule) {
1066                 remap_kernel = true;
1067                 adjust_kernel_syms = dso->adjust_symbols;
1068         }
1069         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1070                 struct symbol *f;
1071                 const char *elf_name = elf_sym__name(&sym, symstrs);
1072                 char *demangled = NULL;
1073                 int is_label = elf_sym__is_label(&sym);
1074                 const char *section_name;
1075                 bool used_opd = false;
1076
1077                 if (!is_label && !elf_sym__filter(&sym))
1078                         continue;
1079
1080                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1081                  * don't identify functions, so will confuse the profile
1082                  * output: */
1083                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1084                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1085                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1086                                 continue;
1087                 }
1088
1089                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1090                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1091                         u64 *opd = opddata->d_buf + offset;
1092                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1093                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1094                                         sym.st_value);
1095                         used_opd = true;
1096                 }
1097                 /*
1098                  * When loading symbols in a data mapping, ABS symbols (which
1099                  * has a value of SHN_ABS in its st_shndx) failed at
1100                  * elf_getscn().  And it marks the loading as a failure so
1101                  * already loaded symbols cannot be fixed up.
1102                  *
1103                  * I'm not sure what should be done. Just ignore them for now.
1104                  * - Namhyung Kim
1105                  */
1106                 if (sym.st_shndx == SHN_ABS)
1107                         continue;
1108
1109                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1110                 if (!sec)
1111                         goto out_elf_end;
1112
1113                 gelf_getshdr(sec, &shdr);
1114
1115                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1116                         continue;
1117
1118                 section_name = elf_sec__name(&shdr, secstrs);
1119
1120                 /* On ARM, symbols for thumb functions have 1 added to
1121                  * the symbol address as a flag - remove it */
1122                 if ((ehdr.e_machine == EM_ARM) &&
1123                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1124                     (sym.st_value & 1))
1125                         --sym.st_value;
1126
1127                 if (dso->kernel || kmodule) {
1128                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1129                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1130                                 goto out_elf_end;
1131                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1132                            (!used_opd && syms_ss->adjust_symbols)) {
1133                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1134                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1135                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1136                                   (u64)shdr.sh_offset);
1137                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1138                 }
1139
1140                 demangled = demangle_sym(dso, kmodule, elf_name);
1141                 if (demangled != NULL)
1142                         elf_name = demangled;
1143
1144                 f = symbol__new(sym.st_value, sym.st_size,
1145                                 GELF_ST_BIND(sym.st_info),
1146                                 GELF_ST_TYPE(sym.st_info), elf_name);
1147                 free(demangled);
1148                 if (!f)
1149                         goto out_elf_end;
1150
1151                 arch__sym_update(f, &sym);
1152
1153                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1154                 nr++;
1155         }
1156
1157         /*
1158          * For misannotated, zeroed, ASM function sizes.
1159          */
1160         if (nr > 0) {
1161                 symbols__fixup_end(&dso->symbols);
1162                 symbols__fixup_duplicate(&dso->symbols);
1163                 if (kmap) {
1164                         /*
1165                          * We need to fixup this here too because we create new
1166                          * maps here, for things like vsyscall sections.
1167                          */
1168                         maps__fixup_end(kmaps);
1169                 }
1170         }
1171         err = nr;
1172 out_elf_end:
1173         return err;
1174 }
1175
1176 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1177 {
1178         GElf_Phdr phdr;
1179         size_t i, phdrnum;
1180         int err;
1181         u64 sz;
1182
1183         if (elf_getphdrnum(elf, &phdrnum))
1184                 return -1;
1185
1186         for (i = 0; i < phdrnum; i++) {
1187                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1188                         return -1;
1189                 if (phdr.p_type != PT_LOAD)
1190                         continue;
1191                 if (exe) {
1192                         if (!(phdr.p_flags & PF_X))
1193                                 continue;
1194                 } else {
1195                         if (!(phdr.p_flags & PF_R))
1196                                 continue;
1197                 }
1198                 sz = min(phdr.p_memsz, phdr.p_filesz);
1199                 if (!sz)
1200                         continue;
1201                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1202                 if (err)
1203                         return err;
1204         }
1205         return 0;
1206 }
1207
1208 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1209                     bool *is_64_bit)
1210 {
1211         int err;
1212         Elf *elf;
1213
1214         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1215         if (elf == NULL)
1216                 return -1;
1217
1218         if (is_64_bit)
1219                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1220
1221         err = elf_read_maps(elf, exe, mapfn, data);
1222
1223         elf_end(elf);
1224         return err;
1225 }
1226
1227 enum dso_type dso__type_fd(int fd)
1228 {
1229         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1230         GElf_Ehdr ehdr;
1231         Elf_Kind ek;
1232         Elf *elf;
1233
1234         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1235         if (elf == NULL)
1236                 goto out;
1237
1238         ek = elf_kind(elf);
1239         if (ek != ELF_K_ELF)
1240                 goto out_end;
1241
1242         if (gelf_getclass(elf) == ELFCLASS64) {
1243                 dso_type = DSO__TYPE_64BIT;
1244                 goto out_end;
1245         }
1246
1247         if (gelf_getehdr(elf, &ehdr) == NULL)
1248                 goto out_end;
1249
1250         if (ehdr.e_machine == EM_X86_64)
1251                 dso_type = DSO__TYPE_X32BIT;
1252         else
1253                 dso_type = DSO__TYPE_32BIT;
1254 out_end:
1255         elf_end(elf);
1256 out:
1257         return dso_type;
1258 }
1259
1260 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1261 {
1262         ssize_t r;
1263         size_t n;
1264         int err = -1;
1265         char *buf = malloc(page_size);
1266
1267         if (buf == NULL)
1268                 return -1;
1269
1270         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1271                 goto out;
1272
1273         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1274                 goto out;
1275
1276         while (len) {
1277                 n = page_size;
1278                 if (len < n)
1279                         n = len;
1280                 /* Use read because mmap won't work on proc files */
1281                 r = read(from, buf, n);
1282                 if (r < 0)
1283                         goto out;
1284                 if (!r)
1285                         break;
1286                 n = r;
1287                 r = write(to, buf, n);
1288                 if (r < 0)
1289                         goto out;
1290                 if ((size_t)r != n)
1291                         goto out;
1292                 len -= n;
1293         }
1294
1295         err = 0;
1296 out:
1297         free(buf);
1298         return err;
1299 }
1300
1301 struct kcore {
1302         int fd;
1303         int elfclass;
1304         Elf *elf;
1305         GElf_Ehdr ehdr;
1306 };
1307
1308 static int kcore__open(struct kcore *kcore, const char *filename)
1309 {
1310         GElf_Ehdr *ehdr;
1311
1312         kcore->fd = open(filename, O_RDONLY);
1313         if (kcore->fd == -1)
1314                 return -1;
1315
1316         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1317         if (!kcore->elf)
1318                 goto out_close;
1319
1320         kcore->elfclass = gelf_getclass(kcore->elf);
1321         if (kcore->elfclass == ELFCLASSNONE)
1322                 goto out_end;
1323
1324         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1325         if (!ehdr)
1326                 goto out_end;
1327
1328         return 0;
1329
1330 out_end:
1331         elf_end(kcore->elf);
1332 out_close:
1333         close(kcore->fd);
1334         return -1;
1335 }
1336
1337 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1338                        bool temp)
1339 {
1340         kcore->elfclass = elfclass;
1341
1342         if (temp)
1343                 kcore->fd = mkstemp(filename);
1344         else
1345                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1346         if (kcore->fd == -1)
1347                 return -1;
1348
1349         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1350         if (!kcore->elf)
1351                 goto out_close;
1352
1353         if (!gelf_newehdr(kcore->elf, elfclass))
1354                 goto out_end;
1355
1356         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1357
1358         return 0;
1359
1360 out_end:
1361         elf_end(kcore->elf);
1362 out_close:
1363         close(kcore->fd);
1364         unlink(filename);
1365         return -1;
1366 }
1367
1368 static void kcore__close(struct kcore *kcore)
1369 {
1370         elf_end(kcore->elf);
1371         close(kcore->fd);
1372 }
1373
1374 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1375 {
1376         GElf_Ehdr *ehdr = &to->ehdr;
1377         GElf_Ehdr *kehdr = &from->ehdr;
1378
1379         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1380         ehdr->e_type      = kehdr->e_type;
1381         ehdr->e_machine   = kehdr->e_machine;
1382         ehdr->e_version   = kehdr->e_version;
1383         ehdr->e_entry     = 0;
1384         ehdr->e_shoff     = 0;
1385         ehdr->e_flags     = kehdr->e_flags;
1386         ehdr->e_phnum     = count;
1387         ehdr->e_shentsize = 0;
1388         ehdr->e_shnum     = 0;
1389         ehdr->e_shstrndx  = 0;
1390
1391         if (from->elfclass == ELFCLASS32) {
1392                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1393                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1394                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1395         } else {
1396                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1397                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1398                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1399         }
1400
1401         if (!gelf_update_ehdr(to->elf, ehdr))
1402                 return -1;
1403
1404         if (!gelf_newphdr(to->elf, count))
1405                 return -1;
1406
1407         return 0;
1408 }
1409
1410 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1411                            u64 addr, u64 len)
1412 {
1413         GElf_Phdr phdr = {
1414                 .p_type         = PT_LOAD,
1415                 .p_flags        = PF_R | PF_W | PF_X,
1416                 .p_offset       = offset,
1417                 .p_vaddr        = addr,
1418                 .p_paddr        = 0,
1419                 .p_filesz       = len,
1420                 .p_memsz        = len,
1421                 .p_align        = page_size,
1422         };
1423
1424         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1425                 return -1;
1426
1427         return 0;
1428 }
1429
1430 static off_t kcore__write(struct kcore *kcore)
1431 {
1432         return elf_update(kcore->elf, ELF_C_WRITE);
1433 }
1434
1435 struct phdr_data {
1436         off_t offset;
1437         off_t rel;
1438         u64 addr;
1439         u64 len;
1440         struct list_head node;
1441         struct phdr_data *remaps;
1442 };
1443
1444 struct sym_data {
1445         u64 addr;
1446         struct list_head node;
1447 };
1448
1449 struct kcore_copy_info {
1450         u64 stext;
1451         u64 etext;
1452         u64 first_symbol;
1453         u64 last_symbol;
1454         u64 first_module;
1455         u64 last_module_symbol;
1456         size_t phnum;
1457         struct list_head phdrs;
1458         struct list_head syms;
1459 };
1460
1461 #define kcore_copy__for_each_phdr(k, p) \
1462         list_for_each_entry((p), &(k)->phdrs, node)
1463
1464 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1465 {
1466         struct phdr_data *p = zalloc(sizeof(*p));
1467
1468         if (p) {
1469                 p->addr   = addr;
1470                 p->len    = len;
1471                 p->offset = offset;
1472         }
1473
1474         return p;
1475 }
1476
1477 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1478                                                  u64 addr, u64 len,
1479                                                  off_t offset)
1480 {
1481         struct phdr_data *p = phdr_data__new(addr, len, offset);
1482
1483         if (p)
1484                 list_add_tail(&p->node, &kci->phdrs);
1485
1486         return p;
1487 }
1488
1489 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1490 {
1491         struct phdr_data *p, *tmp;
1492
1493         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1494                 list_del_init(&p->node);
1495                 free(p);
1496         }
1497 }
1498
1499 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1500                                             u64 addr)
1501 {
1502         struct sym_data *s = zalloc(sizeof(*s));
1503
1504         if (s) {
1505                 s->addr = addr;
1506                 list_add_tail(&s->node, &kci->syms);
1507         }
1508
1509         return s;
1510 }
1511
1512 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1513 {
1514         struct sym_data *s, *tmp;
1515
1516         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1517                 list_del_init(&s->node);
1518                 free(s);
1519         }
1520 }
1521
1522 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1523                                         u64 start)
1524 {
1525         struct kcore_copy_info *kci = arg;
1526
1527         if (!kallsyms__is_function(type))
1528                 return 0;
1529
1530         if (strchr(name, '[')) {
1531                 if (start > kci->last_module_symbol)
1532                         kci->last_module_symbol = start;
1533                 return 0;
1534         }
1535
1536         if (!kci->first_symbol || start < kci->first_symbol)
1537                 kci->first_symbol = start;
1538
1539         if (!kci->last_symbol || start > kci->last_symbol)
1540                 kci->last_symbol = start;
1541
1542         if (!strcmp(name, "_stext")) {
1543                 kci->stext = start;
1544                 return 0;
1545         }
1546
1547         if (!strcmp(name, "_etext")) {
1548                 kci->etext = start;
1549                 return 0;
1550         }
1551
1552         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1553                 return -1;
1554
1555         return 0;
1556 }
1557
1558 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1559                                       const char *dir)
1560 {
1561         char kallsyms_filename[PATH_MAX];
1562
1563         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1564
1565         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1566                 return -1;
1567
1568         if (kallsyms__parse(kallsyms_filename, kci,
1569                             kcore_copy__process_kallsyms) < 0)
1570                 return -1;
1571
1572         return 0;
1573 }
1574
1575 static int kcore_copy__process_modules(void *arg,
1576                                        const char *name __maybe_unused,
1577                                        u64 start, u64 size __maybe_unused)
1578 {
1579         struct kcore_copy_info *kci = arg;
1580
1581         if (!kci->first_module || start < kci->first_module)
1582                 kci->first_module = start;
1583
1584         return 0;
1585 }
1586
1587 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1588                                      const char *dir)
1589 {
1590         char modules_filename[PATH_MAX];
1591
1592         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1593
1594         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1595                 return -1;
1596
1597         if (modules__parse(modules_filename, kci,
1598                            kcore_copy__process_modules) < 0)
1599                 return -1;
1600
1601         return 0;
1602 }
1603
1604 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1605                            u64 pgoff, u64 s, u64 e)
1606 {
1607         u64 len, offset;
1608
1609         if (s < start || s >= end)
1610                 return 0;
1611
1612         offset = (s - start) + pgoff;
1613         len = e < end ? e - s : end - s;
1614
1615         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1616 }
1617
1618 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1619 {
1620         struct kcore_copy_info *kci = data;
1621         u64 end = start + len;
1622         struct sym_data *sdat;
1623
1624         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1625                 return -1;
1626
1627         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1628                             kci->last_module_symbol))
1629                 return -1;
1630
1631         list_for_each_entry(sdat, &kci->syms, node) {
1632                 u64 s = round_down(sdat->addr, page_size);
1633
1634                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1635                         return -1;
1636         }
1637
1638         return 0;
1639 }
1640
1641 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1642 {
1643         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1644                 return -1;
1645
1646         return 0;
1647 }
1648
1649 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1650 {
1651         struct phdr_data *p, *k = NULL;
1652         u64 kend;
1653
1654         if (!kci->stext)
1655                 return;
1656
1657         /* Find phdr that corresponds to the kernel map (contains stext) */
1658         kcore_copy__for_each_phdr(kci, p) {
1659                 u64 pend = p->addr + p->len - 1;
1660
1661                 if (p->addr <= kci->stext && pend >= kci->stext) {
1662                         k = p;
1663                         break;
1664                 }
1665         }
1666
1667         if (!k)
1668                 return;
1669
1670         kend = k->offset + k->len;
1671
1672         /* Find phdrs that remap the kernel */
1673         kcore_copy__for_each_phdr(kci, p) {
1674                 u64 pend = p->offset + p->len;
1675
1676                 if (p == k)
1677                         continue;
1678
1679                 if (p->offset >= k->offset && pend <= kend)
1680                         p->remaps = k;
1681         }
1682 }
1683
1684 static void kcore_copy__layout(struct kcore_copy_info *kci)
1685 {
1686         struct phdr_data *p;
1687         off_t rel = 0;
1688
1689         kcore_copy__find_remaps(kci);
1690
1691         kcore_copy__for_each_phdr(kci, p) {
1692                 if (!p->remaps) {
1693                         p->rel = rel;
1694                         rel += p->len;
1695                 }
1696                 kci->phnum += 1;
1697         }
1698
1699         kcore_copy__for_each_phdr(kci, p) {
1700                 struct phdr_data *k = p->remaps;
1701
1702                 if (k)
1703                         p->rel = p->offset - k->offset + k->rel;
1704         }
1705 }
1706
1707 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1708                                  Elf *elf)
1709 {
1710         if (kcore_copy__parse_kallsyms(kci, dir))
1711                 return -1;
1712
1713         if (kcore_copy__parse_modules(kci, dir))
1714                 return -1;
1715
1716         if (kci->stext)
1717                 kci->stext = round_down(kci->stext, page_size);
1718         else
1719                 kci->stext = round_down(kci->first_symbol, page_size);
1720
1721         if (kci->etext) {
1722                 kci->etext = round_up(kci->etext, page_size);
1723         } else if (kci->last_symbol) {
1724                 kci->etext = round_up(kci->last_symbol, page_size);
1725                 kci->etext += page_size;
1726         }
1727
1728         kci->first_module = round_down(kci->first_module, page_size);
1729
1730         if (kci->last_module_symbol) {
1731                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1732                                                    page_size);
1733                 kci->last_module_symbol += page_size;
1734         }
1735
1736         if (!kci->stext || !kci->etext)
1737                 return -1;
1738
1739         if (kci->first_module && !kci->last_module_symbol)
1740                 return -1;
1741
1742         if (kcore_copy__read_maps(kci, elf))
1743                 return -1;
1744
1745         kcore_copy__layout(kci);
1746
1747         return 0;
1748 }
1749
1750 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1751                                  const char *name)
1752 {
1753         char from_filename[PATH_MAX];
1754         char to_filename[PATH_MAX];
1755
1756         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1757         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1758
1759         return copyfile_mode(from_filename, to_filename, 0400);
1760 }
1761
1762 static int kcore_copy__unlink(const char *dir, const char *name)
1763 {
1764         char filename[PATH_MAX];
1765
1766         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1767
1768         return unlink(filename);
1769 }
1770
1771 static int kcore_copy__compare_fds(int from, int to)
1772 {
1773         char *buf_from;
1774         char *buf_to;
1775         ssize_t ret;
1776         size_t len;
1777         int err = -1;
1778
1779         buf_from = malloc(page_size);
1780         buf_to = malloc(page_size);
1781         if (!buf_from || !buf_to)
1782                 goto out;
1783
1784         while (1) {
1785                 /* Use read because mmap won't work on proc files */
1786                 ret = read(from, buf_from, page_size);
1787                 if (ret < 0)
1788                         goto out;
1789
1790                 if (!ret)
1791                         break;
1792
1793                 len = ret;
1794
1795                 if (readn(to, buf_to, len) != (int)len)
1796                         goto out;
1797
1798                 if (memcmp(buf_from, buf_to, len))
1799                         goto out;
1800         }
1801
1802         err = 0;
1803 out:
1804         free(buf_to);
1805         free(buf_from);
1806         return err;
1807 }
1808
1809 static int kcore_copy__compare_files(const char *from_filename,
1810                                      const char *to_filename)
1811 {
1812         int from, to, err = -1;
1813
1814         from = open(from_filename, O_RDONLY);
1815         if (from < 0)
1816                 return -1;
1817
1818         to = open(to_filename, O_RDONLY);
1819         if (to < 0)
1820                 goto out_close_from;
1821
1822         err = kcore_copy__compare_fds(from, to);
1823
1824         close(to);
1825 out_close_from:
1826         close(from);
1827         return err;
1828 }
1829
1830 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1831                                     const char *name)
1832 {
1833         char from_filename[PATH_MAX];
1834         char to_filename[PATH_MAX];
1835
1836         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1837         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1838
1839         return kcore_copy__compare_files(from_filename, to_filename);
1840 }
1841
1842 /**
1843  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1844  * @from_dir: from directory
1845  * @to_dir: to directory
1846  *
1847  * This function copies kallsyms, modules and kcore files from one directory to
1848  * another.  kallsyms and modules are copied entirely.  Only code segments are
1849  * copied from kcore.  It is assumed that two segments suffice: one for the
1850  * kernel proper and one for all the modules.  The code segments are determined
1851  * from kallsyms and modules files.  The kernel map starts at _stext or the
1852  * lowest function symbol, and ends at _etext or the highest function symbol.
1853  * The module map starts at the lowest module address and ends at the highest
1854  * module symbol.  Start addresses are rounded down to the nearest page.  End
1855  * addresses are rounded up to the nearest page.  An extra page is added to the
1856  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1857  * symbol too.  Because it contains only code sections, the resulting kcore is
1858  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1859  * is not the same for the kernel map and the modules map.  That happens because
1860  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1861  * kallsyms and modules files are compared with their copies to check that
1862  * modules have not been loaded or unloaded while the copies were taking place.
1863  *
1864  * Return: %0 on success, %-1 on failure.
1865  */
1866 int kcore_copy(const char *from_dir, const char *to_dir)
1867 {
1868         struct kcore kcore;
1869         struct kcore extract;
1870         int idx = 0, err = -1;
1871         off_t offset, sz;
1872         struct kcore_copy_info kci = { .stext = 0, };
1873         char kcore_filename[PATH_MAX];
1874         char extract_filename[PATH_MAX];
1875         struct phdr_data *p;
1876
1877         INIT_LIST_HEAD(&kci.phdrs);
1878         INIT_LIST_HEAD(&kci.syms);
1879
1880         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1881                 return -1;
1882
1883         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1884                 goto out_unlink_kallsyms;
1885
1886         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1887         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1888
1889         if (kcore__open(&kcore, kcore_filename))
1890                 goto out_unlink_modules;
1891
1892         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1893                 goto out_kcore_close;
1894
1895         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1896                 goto out_kcore_close;
1897
1898         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1899                 goto out_extract_close;
1900
1901         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1902                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1903         offset = round_up(offset, page_size);
1904
1905         kcore_copy__for_each_phdr(&kci, p) {
1906                 off_t offs = p->rel + offset;
1907
1908                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1909                         goto out_extract_close;
1910         }
1911
1912         sz = kcore__write(&extract);
1913         if (sz < 0 || sz > offset)
1914                 goto out_extract_close;
1915
1916         kcore_copy__for_each_phdr(&kci, p) {
1917                 off_t offs = p->rel + offset;
1918
1919                 if (p->remaps)
1920                         continue;
1921                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1922                         goto out_extract_close;
1923         }
1924
1925         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1926                 goto out_extract_close;
1927
1928         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1929                 goto out_extract_close;
1930
1931         err = 0;
1932
1933 out_extract_close:
1934         kcore__close(&extract);
1935         if (err)
1936                 unlink(extract_filename);
1937 out_kcore_close:
1938         kcore__close(&kcore);
1939 out_unlink_modules:
1940         if (err)
1941                 kcore_copy__unlink(to_dir, "modules");
1942 out_unlink_kallsyms:
1943         if (err)
1944                 kcore_copy__unlink(to_dir, "kallsyms");
1945
1946         kcore_copy__free_phdrs(&kci);
1947         kcore_copy__free_syms(&kci);
1948
1949         return err;
1950 }
1951
1952 int kcore_extract__create(struct kcore_extract *kce)
1953 {
1954         struct kcore kcore;
1955         struct kcore extract;
1956         size_t count = 1;
1957         int idx = 0, err = -1;
1958         off_t offset = page_size, sz;
1959
1960         if (kcore__open(&kcore, kce->kcore_filename))
1961                 return -1;
1962
1963         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1964         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1965                 goto out_kcore_close;
1966
1967         if (kcore__copy_hdr(&kcore, &extract, count))
1968                 goto out_extract_close;
1969
1970         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1971                 goto out_extract_close;
1972
1973         sz = kcore__write(&extract);
1974         if (sz < 0 || sz > offset)
1975                 goto out_extract_close;
1976
1977         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1978                 goto out_extract_close;
1979
1980         err = 0;
1981
1982 out_extract_close:
1983         kcore__close(&extract);
1984         if (err)
1985                 unlink(kce->extract_filename);
1986 out_kcore_close:
1987         kcore__close(&kcore);
1988
1989         return err;
1990 }
1991
1992 void kcore_extract__delete(struct kcore_extract *kce)
1993 {
1994         unlink(kce->extract_filename);
1995 }
1996
1997 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1998
1999 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2000 {
2001         if (!base_off)
2002                 return;
2003
2004         if (tmp->bit32)
2005                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2006                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2007                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2008         else
2009                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2010                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2011                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2012 }
2013
2014 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2015                               GElf_Addr base_off)
2016 {
2017         if (!base_off)
2018                 return;
2019
2020         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2021                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2022         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2023                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2024 }
2025
2026 /**
2027  * populate_sdt_note : Parse raw data and identify SDT note
2028  * @elf: elf of the opened file
2029  * @data: raw data of a section with description offset applied
2030  * @len: note description size
2031  * @type: type of the note
2032  * @sdt_notes: List to add the SDT note
2033  *
2034  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2035  * if its an SDT note, it appends to @sdt_notes list.
2036  */
2037 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2038                              struct list_head *sdt_notes)
2039 {
2040         const char *provider, *name, *args;
2041         struct sdt_note *tmp = NULL;
2042         GElf_Ehdr ehdr;
2043         GElf_Shdr shdr;
2044         int ret = -EINVAL;
2045
2046         union {
2047                 Elf64_Addr a64[NR_ADDR];
2048                 Elf32_Addr a32[NR_ADDR];
2049         } buf;
2050
2051         Elf_Data dst = {
2052                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2053                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2054                 .d_off = 0, .d_align = 0
2055         };
2056         Elf_Data src = {
2057                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2058                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2059                 .d_align = 0
2060         };
2061
2062         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2063         if (!tmp) {
2064                 ret = -ENOMEM;
2065                 goto out_err;
2066         }
2067
2068         INIT_LIST_HEAD(&tmp->note_list);
2069
2070         if (len < dst.d_size + 3)
2071                 goto out_free_note;
2072
2073         /* Translation from file representation to memory representation */
2074         if (gelf_xlatetom(*elf, &dst, &src,
2075                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2076                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2077                 goto out_free_note;
2078         }
2079
2080         /* Populate the fields of sdt_note */
2081         provider = data + dst.d_size;
2082
2083         name = (const char *)memchr(provider, '\0', data + len - provider);
2084         if (name++ == NULL)
2085                 goto out_free_note;
2086
2087         tmp->provider = strdup(provider);
2088         if (!tmp->provider) {
2089                 ret = -ENOMEM;
2090                 goto out_free_note;
2091         }
2092         tmp->name = strdup(name);
2093         if (!tmp->name) {
2094                 ret = -ENOMEM;
2095                 goto out_free_prov;
2096         }
2097
2098         args = memchr(name, '\0', data + len - name);
2099
2100         /*
2101          * There is no argument if:
2102          * - We reached the end of the note;
2103          * - There is not enough room to hold a potential string;
2104          * - The argument string is empty or just contains ':'.
2105          */
2106         if (args == NULL || data + len - args < 2 ||
2107                 args[1] == ':' || args[1] == '\0')
2108                 tmp->args = NULL;
2109         else {
2110                 tmp->args = strdup(++args);
2111                 if (!tmp->args) {
2112                         ret = -ENOMEM;
2113                         goto out_free_name;
2114                 }
2115         }
2116
2117         if (gelf_getclass(*elf) == ELFCLASS32) {
2118                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2119                 tmp->bit32 = true;
2120         } else {
2121                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2122                 tmp->bit32 = false;
2123         }
2124
2125         if (!gelf_getehdr(*elf, &ehdr)) {
2126                 pr_debug("%s : cannot get elf header.\n", __func__);
2127                 ret = -EBADF;
2128                 goto out_free_args;
2129         }
2130
2131         /* Adjust the prelink effect :
2132          * Find out the .stapsdt.base section.
2133          * This scn will help us to handle prelinking (if present).
2134          * Compare the retrieved file offset of the base section with the
2135          * base address in the description of the SDT note. If its different,
2136          * then accordingly, adjust the note location.
2137          */
2138         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2139                 sdt_adjust_loc(tmp, shdr.sh_offset);
2140
2141         /* Adjust reference counter offset */
2142         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2143                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2144
2145         list_add_tail(&tmp->note_list, sdt_notes);
2146         return 0;
2147
2148 out_free_args:
2149         zfree(&tmp->args);
2150 out_free_name:
2151         zfree(&tmp->name);
2152 out_free_prov:
2153         zfree(&tmp->provider);
2154 out_free_note:
2155         free(tmp);
2156 out_err:
2157         return ret;
2158 }
2159
2160 /**
2161  * construct_sdt_notes_list : constructs a list of SDT notes
2162  * @elf : elf to look into
2163  * @sdt_notes : empty list_head
2164  *
2165  * Scans the sections in 'elf' for the section
2166  * .note.stapsdt. It, then calls populate_sdt_note to find
2167  * out the SDT events and populates the 'sdt_notes'.
2168  */
2169 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2170 {
2171         GElf_Ehdr ehdr;
2172         Elf_Scn *scn = NULL;
2173         Elf_Data *data;
2174         GElf_Shdr shdr;
2175         size_t shstrndx, next;
2176         GElf_Nhdr nhdr;
2177         size_t name_off, desc_off, offset;
2178         int ret = 0;
2179
2180         if (gelf_getehdr(elf, &ehdr) == NULL) {
2181                 ret = -EBADF;
2182                 goto out_ret;
2183         }
2184         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2185                 ret = -EBADF;
2186                 goto out_ret;
2187         }
2188
2189         /* Look for the required section */
2190         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2191         if (!scn) {
2192                 ret = -ENOENT;
2193                 goto out_ret;
2194         }
2195
2196         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2197                 ret = -ENOENT;
2198                 goto out_ret;
2199         }
2200
2201         data = elf_getdata(scn, NULL);
2202
2203         /* Get the SDT notes */
2204         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2205                                               &desc_off)) > 0; offset = next) {
2206                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2207                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2208                             sizeof(SDT_NOTE_NAME))) {
2209                         /* Check the type of the note */
2210                         if (nhdr.n_type != SDT_NOTE_TYPE)
2211                                 goto out_ret;
2212
2213                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2214                                                 nhdr.n_descsz, sdt_notes);
2215                         if (ret < 0)
2216                                 goto out_ret;
2217                 }
2218         }
2219         if (list_empty(sdt_notes))
2220                 ret = -ENOENT;
2221
2222 out_ret:
2223         return ret;
2224 }
2225
2226 /**
2227  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2228  * @head : empty list_head
2229  * @target : file to find SDT notes from
2230  *
2231  * This opens the file, initializes
2232  * the ELF and then calls construct_sdt_notes_list.
2233  */
2234 int get_sdt_note_list(struct list_head *head, const char *target)
2235 {
2236         Elf *elf;
2237         int fd, ret;
2238
2239         fd = open(target, O_RDONLY);
2240         if (fd < 0)
2241                 return -EBADF;
2242
2243         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2244         if (!elf) {
2245                 ret = -EBADF;
2246                 goto out_close;
2247         }
2248         ret = construct_sdt_notes_list(elf, head);
2249         elf_end(elf);
2250 out_close:
2251         close(fd);
2252         return ret;
2253 }
2254
2255 /**
2256  * cleanup_sdt_note_list : free the sdt notes' list
2257  * @sdt_notes: sdt notes' list
2258  *
2259  * Free up the SDT notes in @sdt_notes.
2260  * Returns the number of SDT notes free'd.
2261  */
2262 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2263 {
2264         struct sdt_note *tmp, *pos;
2265         int nr_free = 0;
2266
2267         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2268                 list_del_init(&pos->note_list);
2269                 zfree(&pos->name);
2270                 zfree(&pos->provider);
2271                 free(pos);
2272                 nr_free++;
2273         }
2274         return nr_free;
2275 }
2276
2277 /**
2278  * sdt_notes__get_count: Counts the number of sdt events
2279  * @start: list_head to sdt_notes list
2280  *
2281  * Returns the number of SDT notes in a list
2282  */
2283 int sdt_notes__get_count(struct list_head *start)
2284 {
2285         struct sdt_note *sdt_ptr;
2286         int count = 0;
2287
2288         list_for_each_entry(sdt_ptr, start, note_list)
2289                 count++;
2290         return count;
2291 }
2292 #endif
2293
2294 void symbol__elf_init(void)
2295 {
2296         elf_version(EV_CURRENT);
2297 }