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 elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 708 {
 709         /*
 710          * Usually vmlinux is an ELF file with type ET_EXEC for most
 711          * architectures; except Arm64 kernel is linked with option
 712          * '-share', so need to check type ET_DYN.
 713          */
 714         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
 715                ehdr.e_type == ET_DYN;
 716 }
 717
 718 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 719                  enum dso_binary_type type)
 720 {
 721         GElf_Ehdr ehdr;
 722         Elf *elf;
 723         int fd;
 724
 725         if (dso__needs_decompress(dso)) {
 726                 fd = dso__decompress_kmodule_fd(dso, name);
 727                 if (fd < 0)
 728                         return -1;
 729
 730                 type = dso->symtab_type;
 731         } else {
 732                 fd = open(name, O_RDONLY);
 733                 if (fd < 0) {
 734                         dso->load_errno = errno;
 735                         return -1;
 736                 }
 737         }
 738
 739         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 740         if (elf == NULL) {
 741                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 742                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 743                 goto out_close;
 744         }
 745
 746         if (gelf_getehdr(elf, &ehdr) == NULL) {
 747                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 748                 pr_debug("%s: cannot get elf header.\n", __func__);
 749                 goto out_elf_end;
 750         }
 751
 752         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 753                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 754                 goto out_elf_end;
 755         }
 756
 757         /* Always reject images with a mismatched build-id: */
 758         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 759                 u8 build_id[BUILD_ID_SIZE];
 760
 761                 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
 762                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 763                         goto out_elf_end;
 764                 }
 765
 766                 if (!dso__build_id_equal(dso, build_id)) {
 767                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 768                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 769                         goto out_elf_end;
 770                 }
 771         }
 772
 773         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 774
 775         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 776                         NULL);
 777         if (ss->symshdr.sh_type != SHT_SYMTAB)
 778                 ss->symtab = NULL;
 779
 780         ss->dynsym_idx = 0;
 781         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 782                         &ss->dynsym_idx);
 783         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 784                 ss->dynsym = NULL;
 785
 786         ss->opdidx = 0;
 787         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 788                         &ss->opdidx);
 789         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 790                 ss->opdsec = NULL;
 791
 792         if (dso->kernel == DSO_SPACE__USER)
 793                 ss->adjust_symbols = true;
 794         else
 795                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 796
 797         ss->name   = strdup(name);
 798         if (!ss->name) {
 799                 dso->load_errno = errno;
 800                 goto out_elf_end;
 801         }
 802
 803         ss->elf    = elf;
 804         ss->fd     = fd;
 805         ss->ehdr   = ehdr;
 806         ss->type   = type;
 807
 808         return 0;
 809
 810 out_elf_end:
 811         elf_end(elf);
 812 out_close:
 813         close(fd);
 814         return -1;
 815 }
 816
 817 /**
 818  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 819  * @kmap: kernel maps and relocation reference symbol
 820  *
 821  * This function returns %true if we are dealing with the kernel maps and the
 822  * relocation reference symbol has not yet been found.  Otherwise %false is
 823  * returned.
 824  */
 825 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 826 {
 827         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 828                !kmap->ref_reloc_sym->unrelocated_addr;
 829 }
 830
 831 /**
 832  * ref_reloc - kernel relocation offset.
 833  * @kmap: kernel maps and relocation reference symbol
 834  *
 835  * This function returns the offset of kernel addresses as determined by using
 836  * the relocation reference symbol i.e. if the kernel has not been relocated
 837  * then the return value is zero.
 838  */
 839 static u64 ref_reloc(struct kmap *kmap)
 840 {
 841         if (kmap && kmap->ref_reloc_sym &&
 842             kmap->ref_reloc_sym->unrelocated_addr)
 843                 return kmap->ref_reloc_sym->addr -
 844                        kmap->ref_reloc_sym->unrelocated_addr;
 845         return 0;
 846 }
 847
 848 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 849                 GElf_Sym *sym __maybe_unused) { }
 850
 851 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 852                                       GElf_Sym *sym, GElf_Shdr *shdr,
 853                                       struct maps *kmaps, struct kmap *kmap,
 854                                       struct dso **curr_dsop, struct map **curr_mapp,
 855                                       const char *section_name,
 856                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 857 {
 858         struct dso *curr_dso = *curr_dsop;
 859         struct map *curr_map;
 860         char dso_name[PATH_MAX];
 861
 862         /* Adjust symbol to map to file offset */
 863         if (adjust_kernel_syms)
 864                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
 865
 866         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
 867                 return 0;
 868
 869         if (strcmp(section_name, ".text") == 0) {
 870                 /*
 871                  * The initial kernel mapping is based on
 872                  * kallsyms and identity maps.  Overwrite it to
 873                  * map to the kernel dso.
 874                  */
 875                 if (*remap_kernel && dso->kernel && !kmodule) {
 876                         *remap_kernel = false;
 877                         map->start = shdr->sh_addr + ref_reloc(kmap);
 878                         map->end = map->start + shdr->sh_size;
 879                         map->pgoff = shdr->sh_offset;
 880                         map->map_ip = map__map_ip;
 881                         map->unmap_ip = map__unmap_ip;
 882                         /* Ensure maps are correctly ordered */
 883                         if (kmaps) {
 884                                 map__get(map);
 885                                 maps__remove(kmaps, map);
 886                                 maps__insert(kmaps, map);
 887                                 map__put(map);
 888                         }
 889                 }
 890
 891                 /*
 892                  * The initial module mapping is based on
 893                  * /proc/modules mapped to offset zero.
 894                  * Overwrite it to map to the module dso.
 895                  */
 896                 if (*remap_kernel && kmodule) {
 897                         *remap_kernel = false;
 898                         map->pgoff = shdr->sh_offset;
 899                 }
 900
 901                 *curr_mapp = map;
 902                 *curr_dsop = dso;
 903                 return 0;
 904         }
 905
 906         if (!kmap)
 907                 return 0;
 908
 909         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
 910
 911         curr_map = maps__find_by_name(kmaps, dso_name);
 912         if (curr_map == NULL) {
 913                 u64 start = sym->st_value;
 914
 915                 if (kmodule)
 916                         start += map->start + shdr->sh_offset;
 917
 918                 curr_dso = dso__new(dso_name);
 919                 if (curr_dso == NULL)
 920                         return -1;
 921                 curr_dso->kernel = dso->kernel;
 922                 curr_dso->long_name = dso->long_name;
 923                 curr_dso->long_name_len = dso->long_name_len;
 924                 curr_map = map__new2(start, curr_dso);
 925                 dso__put(curr_dso);
 926                 if (curr_map == NULL)
 927                         return -1;
 928
 929                 if (curr_dso->kernel)
 930                         map__kmap(curr_map)->kmaps = kmaps;
 931
 932                 if (adjust_kernel_syms) {
 933                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
 934                         curr_map->end    = curr_map->start + shdr->sh_size;
 935                         curr_map->pgoff  = shdr->sh_offset;
 936                 } else {
 937                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 938                 }
 939                 curr_dso->symtab_type = dso->symtab_type;
 940                 maps__insert(kmaps, curr_map);
 941                 /*
 942                  * Add it before we drop the referece to curr_map, i.e. while
 943                  * we still are sure to have a reference to this DSO via
 944                  * *curr_map->dso.
 945                  */
 946                 dsos__add(&kmaps->machine->dsos, curr_dso);
 947                 /* kmaps already got it */
 948                 map__put(curr_map);
 949                 dso__set_loaded(curr_dso);
 950                 *curr_mapp = curr_map;
 951                 *curr_dsop = curr_dso;
 952         } else
 953                 *curr_dsop = curr_map->dso;
 954
 955         return 0;
 956 }
 957
 958 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 959                   struct symsrc *runtime_ss, int kmodule)
 960 {
 961         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
 962         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
 963         struct map *curr_map = map;
 964         struct dso *curr_dso = dso;
 965         Elf_Data *symstrs, *secstrs;
 966         uint32_t nr_syms;
 967         int err = -1;
 968         uint32_t idx;
 969         GElf_Ehdr ehdr;
 970         GElf_Shdr shdr;
 971         GElf_Shdr tshdr;
 972         Elf_Data *syms, *opddata = NULL;
 973         GElf_Sym sym;
 974         Elf_Scn *sec, *sec_strndx;
 975         Elf *elf;
 976         int nr = 0;
 977         bool remap_kernel = false, adjust_kernel_syms = false;
 978
 979         if (kmap && !kmaps)
 980                 return -1;
 981
 982         dso->symtab_type = syms_ss->type;
 983         dso->is_64_bit = syms_ss->is_64_bit;
 984         dso->rel = syms_ss->ehdr.e_type == ET_REL;
 985
 986         /*
 987          * Modules may already have symbols from kallsyms, but those symbols
 988          * have the wrong values for the dso maps, so remove them.
 989          */
 990         if (kmodule && syms_ss->symtab)
 991                 symbols__delete(&dso->symbols);
 992
 993         if (!syms_ss->symtab) {
 994                 /*
 995                  * If the vmlinux is stripped, fail so we will fall back
 996                  * to using kallsyms. The vmlinux runtime symbols aren't
 997                  * of much use.
 998                  */
 999                 if (dso->kernel)
1000                         goto out_elf_end;
1001
1002                 syms_ss->symtab  = syms_ss->dynsym;
1003                 syms_ss->symshdr = syms_ss->dynshdr;
1004         }
1005
1006         elf = syms_ss->elf;
1007         ehdr = syms_ss->ehdr;
1008         sec = syms_ss->symtab;
1009         shdr = syms_ss->symshdr;
1010
1011         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1012                                 ".text", NULL))
1013                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1014
1015         if (runtime_ss->opdsec)
1016                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1017
1018         syms = elf_getdata(sec, NULL);
1019         if (syms == NULL)
1020                 goto out_elf_end;
1021
1022         sec = elf_getscn(elf, shdr.sh_link);
1023         if (sec == NULL)
1024                 goto out_elf_end;
1025
1026         symstrs = elf_getdata(sec, NULL);
1027         if (symstrs == NULL)
1028                 goto out_elf_end;
1029
1030         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1031         if (sec_strndx == NULL)
1032                 goto out_elf_end;
1033
1034         secstrs = elf_getdata(sec_strndx, NULL);
1035         if (secstrs == NULL)
1036                 goto out_elf_end;
1037
1038         nr_syms = shdr.sh_size / shdr.sh_entsize;
1039
1040         memset(&sym, 0, sizeof(sym));
1041
1042         /*
1043          * The kernel relocation symbol is needed in advance in order to adjust
1044          * kernel maps correctly.
1045          */
1046         if (ref_reloc_sym_not_found(kmap)) {
1047                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1048                         const char *elf_name = elf_sym__name(&sym, symstrs);
1049
1050                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1051                                 continue;
1052                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1053                         map->reloc = kmap->ref_reloc_sym->addr -
1054                                      kmap->ref_reloc_sym->unrelocated_addr;
1055                         break;
1056                 }
1057         }
1058
1059         /*
1060          * Handle any relocation of vdso necessary because older kernels
1061          * attempted to prelink vdso to its virtual address.
1062          */
1063         if (dso__is_vdso(dso))
1064                 map->reloc = map->start - dso->text_offset;
1065
1066         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1067         /*
1068          * Initial kernel and module mappings do not map to the dso.
1069          * Flag the fixups.
1070          */
1071         if (dso->kernel) {
1072                 remap_kernel = true;
1073                 adjust_kernel_syms = dso->adjust_symbols;
1074         }
1075         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1076                 struct symbol *f;
1077                 const char *elf_name = elf_sym__name(&sym, symstrs);
1078                 char *demangled = NULL;
1079                 int is_label = elf_sym__is_label(&sym);
1080                 const char *section_name;
1081                 bool used_opd = false;
1082
1083                 if (!is_label && !elf_sym__filter(&sym))
1084                         continue;
1085
1086                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1087                  * don't identify functions, so will confuse the profile
1088                  * output: */
1089                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1090                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1091                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1092                                 continue;
1093                 }
1094
1095                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1096                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1097                         u64 *opd = opddata->d_buf + offset;
1098                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1099                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1100                                         sym.st_value);
1101                         used_opd = true;
1102                 }
1103                 /*
1104                  * When loading symbols in a data mapping, ABS symbols (which
1105                  * has a value of SHN_ABS in its st_shndx) failed at
1106                  * elf_getscn().  And it marks the loading as a failure so
1107                  * already loaded symbols cannot be fixed up.
1108                  *
1109                  * I'm not sure what should be done. Just ignore them for now.
1110                  * - Namhyung Kim
1111                  */
1112                 if (sym.st_shndx == SHN_ABS)
1113                         continue;
1114
1115                 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1116                 if (!sec)
1117                         goto out_elf_end;
1118
1119                 gelf_getshdr(sec, &shdr);
1120
1121                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1122                         continue;
1123
1124                 section_name = elf_sec__name(&shdr, secstrs);
1125
1126                 /* On ARM, symbols for thumb functions have 1 added to
1127                  * the symbol address as a flag - remove it */
1128                 if ((ehdr.e_machine == EM_ARM) &&
1129                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1130                     (sym.st_value & 1))
1131                         --sym.st_value;
1132
1133                 if (dso->kernel) {
1134                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1135                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1136                                 goto out_elf_end;
1137                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1138                            (!used_opd && syms_ss->adjust_symbols)) {
1139                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1140                                   "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1141                                   (u64)sym.st_value, (u64)shdr.sh_addr,
1142                                   (u64)shdr.sh_offset);
1143                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1144                 }
1145
1146                 demangled = demangle_sym(dso, kmodule, elf_name);
1147                 if (demangled != NULL)
1148                         elf_name = demangled;
1149
1150                 f = symbol__new(sym.st_value, sym.st_size,
1151                                 GELF_ST_BIND(sym.st_info),
1152                                 GELF_ST_TYPE(sym.st_info), elf_name);
1153                 free(demangled);
1154                 if (!f)
1155                         goto out_elf_end;
1156
1157                 arch__sym_update(f, &sym);
1158
1159                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1160                 nr++;
1161         }
1162
1163         /*
1164          * For misannotated, zeroed, ASM function sizes.
1165          */
1166         if (nr > 0) {
1167                 symbols__fixup_end(&dso->symbols);
1168                 symbols__fixup_duplicate(&dso->symbols);
1169                 if (kmap) {
1170                         /*
1171                          * We need to fixup this here too because we create new
1172                          * maps here, for things like vsyscall sections.
1173                          */
1174                         maps__fixup_end(kmaps);
1175                 }
1176         }
1177         err = nr;
1178 out_elf_end:
1179         return err;
1180 }
1181
1182 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1183 {
1184         GElf_Phdr phdr;
1185         size_t i, phdrnum;
1186         int err;
1187         u64 sz;
1188
1189         if (elf_getphdrnum(elf, &phdrnum))
1190                 return -1;
1191
1192         for (i = 0; i < phdrnum; i++) {
1193                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1194                         return -1;
1195                 if (phdr.p_type != PT_LOAD)
1196                         continue;
1197                 if (exe) {
1198                         if (!(phdr.p_flags & PF_X))
1199                                 continue;
1200                 } else {
1201                         if (!(phdr.p_flags & PF_R))
1202                                 continue;
1203                 }
1204                 sz = min(phdr.p_memsz, phdr.p_filesz);
1205                 if (!sz)
1206                         continue;
1207                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1208                 if (err)
1209                         return err;
1210         }
1211         return 0;
1212 }
1213
1214 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1215                     bool *is_64_bit)
1216 {
1217         int err;
1218         Elf *elf;
1219
1220         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1221         if (elf == NULL)
1222                 return -1;
1223
1224         if (is_64_bit)
1225                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1226
1227         err = elf_read_maps(elf, exe, mapfn, data);
1228
1229         elf_end(elf);
1230         return err;
1231 }
1232
1233 enum dso_type dso__type_fd(int fd)
1234 {
1235         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1236         GElf_Ehdr ehdr;
1237         Elf_Kind ek;
1238         Elf *elf;
1239
1240         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1241         if (elf == NULL)
1242                 goto out;
1243
1244         ek = elf_kind(elf);
1245         if (ek != ELF_K_ELF)
1246                 goto out_end;
1247
1248         if (gelf_getclass(elf) == ELFCLASS64) {
1249                 dso_type = DSO__TYPE_64BIT;
1250                 goto out_end;
1251         }
1252
1253         if (gelf_getehdr(elf, &ehdr) == NULL)
1254                 goto out_end;
1255
1256         if (ehdr.e_machine == EM_X86_64)
1257                 dso_type = DSO__TYPE_X32BIT;
1258         else
1259                 dso_type = DSO__TYPE_32BIT;
1260 out_end:
1261         elf_end(elf);
1262 out:
1263         return dso_type;
1264 }
1265
1266 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1267 {
1268         ssize_t r;
1269         size_t n;
1270         int err = -1;
1271         char *buf = malloc(page_size);
1272
1273         if (buf == NULL)
1274                 return -1;
1275
1276         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1277                 goto out;
1278
1279         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1280                 goto out;
1281
1282         while (len) {
1283                 n = page_size;
1284                 if (len < n)
1285                         n = len;
1286                 /* Use read because mmap won't work on proc files */
1287                 r = read(from, buf, n);
1288                 if (r < 0)
1289                         goto out;
1290                 if (!r)
1291                         break;
1292                 n = r;
1293                 r = write(to, buf, n);
1294                 if (r < 0)
1295                         goto out;
1296                 if ((size_t)r != n)
1297                         goto out;
1298                 len -= n;
1299         }
1300
1301         err = 0;
1302 out:
1303         free(buf);
1304         return err;
1305 }
1306
1307 struct kcore {
1308         int fd;
1309         int elfclass;
1310         Elf *elf;
1311         GElf_Ehdr ehdr;
1312 };
1313
1314 static int kcore__open(struct kcore *kcore, const char *filename)
1315 {
1316         GElf_Ehdr *ehdr;
1317
1318         kcore->fd = open(filename, O_RDONLY);
1319         if (kcore->fd == -1)
1320                 return -1;
1321
1322         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1323         if (!kcore->elf)
1324                 goto out_close;
1325
1326         kcore->elfclass = gelf_getclass(kcore->elf);
1327         if (kcore->elfclass == ELFCLASSNONE)
1328                 goto out_end;
1329
1330         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1331         if (!ehdr)
1332                 goto out_end;
1333
1334         return 0;
1335
1336 out_end:
1337         elf_end(kcore->elf);
1338 out_close:
1339         close(kcore->fd);
1340         return -1;
1341 }
1342
1343 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1344                        bool temp)
1345 {
1346         kcore->elfclass = elfclass;
1347
1348         if (temp)
1349                 kcore->fd = mkstemp(filename);
1350         else
1351                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1352         if (kcore->fd == -1)
1353                 return -1;
1354
1355         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1356         if (!kcore->elf)
1357                 goto out_close;
1358
1359         if (!gelf_newehdr(kcore->elf, elfclass))
1360                 goto out_end;
1361
1362         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1363
1364         return 0;
1365
1366 out_end:
1367         elf_end(kcore->elf);
1368 out_close:
1369         close(kcore->fd);
1370         unlink(filename);
1371         return -1;
1372 }
1373
1374 static void kcore__close(struct kcore *kcore)
1375 {
1376         elf_end(kcore->elf);
1377         close(kcore->fd);
1378 }
1379
1380 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1381 {
1382         GElf_Ehdr *ehdr = &to->ehdr;
1383         GElf_Ehdr *kehdr = &from->ehdr;
1384
1385         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1386         ehdr->e_type      = kehdr->e_type;
1387         ehdr->e_machine   = kehdr->e_machine;
1388         ehdr->e_version   = kehdr->e_version;
1389         ehdr->e_entry     = 0;
1390         ehdr->e_shoff     = 0;
1391         ehdr->e_flags     = kehdr->e_flags;
1392         ehdr->e_phnum     = count;
1393         ehdr->e_shentsize = 0;
1394         ehdr->e_shnum     = 0;
1395         ehdr->e_shstrndx  = 0;
1396
1397         if (from->elfclass == ELFCLASS32) {
1398                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1399                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1400                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1401         } else {
1402                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1403                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1404                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1405         }
1406
1407         if (!gelf_update_ehdr(to->elf, ehdr))
1408                 return -1;
1409
1410         if (!gelf_newphdr(to->elf, count))
1411                 return -1;
1412
1413         return 0;
1414 }
1415
1416 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1417                            u64 addr, u64 len)
1418 {
1419         GElf_Phdr phdr = {
1420                 .p_type         = PT_LOAD,
1421                 .p_flags        = PF_R | PF_W | PF_X,
1422                 .p_offset       = offset,
1423                 .p_vaddr        = addr,
1424                 .p_paddr        = 0,
1425                 .p_filesz       = len,
1426                 .p_memsz        = len,
1427                 .p_align        = page_size,
1428         };
1429
1430         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1431                 return -1;
1432
1433         return 0;
1434 }
1435
1436 static off_t kcore__write(struct kcore *kcore)
1437 {
1438         return elf_update(kcore->elf, ELF_C_WRITE);
1439 }
1440
1441 struct phdr_data {
1442         off_t offset;
1443         off_t rel;
1444         u64 addr;
1445         u64 len;
1446         struct list_head node;
1447         struct phdr_data *remaps;
1448 };
1449
1450 struct sym_data {
1451         u64 addr;
1452         struct list_head node;
1453 };
1454
1455 struct kcore_copy_info {
1456         u64 stext;
1457         u64 etext;
1458         u64 first_symbol;
1459         u64 last_symbol;
1460         u64 first_module;
1461         u64 first_module_symbol;
1462         u64 last_module_symbol;
1463         size_t phnum;
1464         struct list_head phdrs;
1465         struct list_head syms;
1466 };
1467
1468 #define kcore_copy__for_each_phdr(k, p) \
1469         list_for_each_entry((p), &(k)->phdrs, node)
1470
1471 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1472 {
1473         struct phdr_data *p = zalloc(sizeof(*p));
1474
1475         if (p) {
1476                 p->addr   = addr;
1477                 p->len    = len;
1478                 p->offset = offset;
1479         }
1480
1481         return p;
1482 }
1483
1484 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1485                                                  u64 addr, u64 len,
1486                                                  off_t offset)
1487 {
1488         struct phdr_data *p = phdr_data__new(addr, len, offset);
1489
1490         if (p)
1491                 list_add_tail(&p->node, &kci->phdrs);
1492
1493         return p;
1494 }
1495
1496 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1497 {
1498         struct phdr_data *p, *tmp;
1499
1500         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1501                 list_del_init(&p->node);
1502                 free(p);
1503         }
1504 }
1505
1506 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1507                                             u64 addr)
1508 {
1509         struct sym_data *s = zalloc(sizeof(*s));
1510
1511         if (s) {
1512                 s->addr = addr;
1513                 list_add_tail(&s->node, &kci->syms);
1514         }
1515
1516         return s;
1517 }
1518
1519 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1520 {
1521         struct sym_data *s, *tmp;
1522
1523         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1524                 list_del_init(&s->node);
1525                 free(s);
1526         }
1527 }
1528
1529 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1530                                         u64 start)
1531 {
1532         struct kcore_copy_info *kci = arg;
1533
1534         if (!kallsyms__is_function(type))
1535                 return 0;
1536
1537         if (strchr(name, '[')) {
1538                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1539                         kci->first_module_symbol = start;
1540                 if (start > kci->last_module_symbol)
1541                         kci->last_module_symbol = start;
1542                 return 0;
1543         }
1544
1545         if (!kci->first_symbol || start < kci->first_symbol)
1546                 kci->first_symbol = start;
1547
1548         if (!kci->last_symbol || start > kci->last_symbol)
1549                 kci->last_symbol = start;
1550
1551         if (!strcmp(name, "_stext")) {
1552                 kci->stext = start;
1553                 return 0;
1554         }
1555
1556         if (!strcmp(name, "_etext")) {
1557                 kci->etext = start;
1558                 return 0;
1559         }
1560
1561         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1562                 return -1;
1563
1564         return 0;
1565 }
1566
1567 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1568                                       const char *dir)
1569 {
1570         char kallsyms_filename[PATH_MAX];
1571
1572         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1573
1574         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1575                 return -1;
1576
1577         if (kallsyms__parse(kallsyms_filename, kci,
1578                             kcore_copy__process_kallsyms) < 0)
1579                 return -1;
1580
1581         return 0;
1582 }
1583
1584 static int kcore_copy__process_modules(void *arg,
1585                                        const char *name __maybe_unused,
1586                                        u64 start, u64 size __maybe_unused)
1587 {
1588         struct kcore_copy_info *kci = arg;
1589
1590         if (!kci->first_module || start < kci->first_module)
1591                 kci->first_module = start;
1592
1593         return 0;
1594 }
1595
1596 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1597                                      const char *dir)
1598 {
1599         char modules_filename[PATH_MAX];
1600
1601         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1602
1603         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1604                 return -1;
1605
1606         if (modules__parse(modules_filename, kci,
1607                            kcore_copy__process_modules) < 0)
1608                 return -1;
1609
1610         return 0;
1611 }
1612
1613 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1614                            u64 pgoff, u64 s, u64 e)
1615 {
1616         u64 len, offset;
1617
1618         if (s < start || s >= end)
1619                 return 0;
1620
1621         offset = (s - start) + pgoff;
1622         len = e < end ? e - s : end - s;
1623
1624         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1625 }
1626
1627 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1628 {
1629         struct kcore_copy_info *kci = data;
1630         u64 end = start + len;
1631         struct sym_data *sdat;
1632
1633         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1634                 return -1;
1635
1636         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1637                             kci->last_module_symbol))
1638                 return -1;
1639
1640         list_for_each_entry(sdat, &kci->syms, node) {
1641                 u64 s = round_down(sdat->addr, page_size);
1642
1643                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1644                         return -1;
1645         }
1646
1647         return 0;
1648 }
1649
1650 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1651 {
1652         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1653                 return -1;
1654
1655         return 0;
1656 }
1657
1658 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1659 {
1660         struct phdr_data *p, *k = NULL;
1661         u64 kend;
1662
1663         if (!kci->stext)
1664                 return;
1665
1666         /* Find phdr that corresponds to the kernel map (contains stext) */
1667         kcore_copy__for_each_phdr(kci, p) {
1668                 u64 pend = p->addr + p->len - 1;
1669
1670                 if (p->addr <= kci->stext && pend >= kci->stext) {
1671                         k = p;
1672                         break;
1673                 }
1674         }
1675
1676         if (!k)
1677                 return;
1678
1679         kend = k->offset + k->len;
1680
1681         /* Find phdrs that remap the kernel */
1682         kcore_copy__for_each_phdr(kci, p) {
1683                 u64 pend = p->offset + p->len;
1684
1685                 if (p == k)
1686                         continue;
1687
1688                 if (p->offset >= k->offset && pend <= kend)
1689                         p->remaps = k;
1690         }
1691 }
1692
1693 static void kcore_copy__layout(struct kcore_copy_info *kci)
1694 {
1695         struct phdr_data *p;
1696         off_t rel = 0;
1697
1698         kcore_copy__find_remaps(kci);
1699
1700         kcore_copy__for_each_phdr(kci, p) {
1701                 if (!p->remaps) {
1702                         p->rel = rel;
1703                         rel += p->len;
1704                 }
1705                 kci->phnum += 1;
1706         }
1707
1708         kcore_copy__for_each_phdr(kci, p) {
1709                 struct phdr_data *k = p->remaps;
1710
1711                 if (k)
1712                         p->rel = p->offset - k->offset + k->rel;
1713         }
1714 }
1715
1716 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1717                                  Elf *elf)
1718 {
1719         if (kcore_copy__parse_kallsyms(kci, dir))
1720                 return -1;
1721
1722         if (kcore_copy__parse_modules(kci, dir))
1723                 return -1;
1724
1725         if (kci->stext)
1726                 kci->stext = round_down(kci->stext, page_size);
1727         else
1728                 kci->stext = round_down(kci->first_symbol, page_size);
1729
1730         if (kci->etext) {
1731                 kci->etext = round_up(kci->etext, page_size);
1732         } else if (kci->last_symbol) {
1733                 kci->etext = round_up(kci->last_symbol, page_size);
1734                 kci->etext += page_size;
1735         }
1736
1737         if (kci->first_module_symbol &&
1738             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1739                 kci->first_module = kci->first_module_symbol;
1740
1741         kci->first_module = round_down(kci->first_module, page_size);
1742
1743         if (kci->last_module_symbol) {
1744                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1745                                                    page_size);
1746                 kci->last_module_symbol += page_size;
1747         }
1748
1749         if (!kci->stext || !kci->etext)
1750                 return -1;
1751
1752         if (kci->first_module && !kci->last_module_symbol)
1753                 return -1;
1754
1755         if (kcore_copy__read_maps(kci, elf))
1756                 return -1;
1757
1758         kcore_copy__layout(kci);
1759
1760         return 0;
1761 }
1762
1763 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1764                                  const char *name)
1765 {
1766         char from_filename[PATH_MAX];
1767         char to_filename[PATH_MAX];
1768
1769         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1770         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1771
1772         return copyfile_mode(from_filename, to_filename, 0400);
1773 }
1774
1775 static int kcore_copy__unlink(const char *dir, const char *name)
1776 {
1777         char filename[PATH_MAX];
1778
1779         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1780
1781         return unlink(filename);
1782 }
1783
1784 static int kcore_copy__compare_fds(int from, int to)
1785 {
1786         char *buf_from;
1787         char *buf_to;
1788         ssize_t ret;
1789         size_t len;
1790         int err = -1;
1791
1792         buf_from = malloc(page_size);
1793         buf_to = malloc(page_size);
1794         if (!buf_from || !buf_to)
1795                 goto out;
1796
1797         while (1) {
1798                 /* Use read because mmap won't work on proc files */
1799                 ret = read(from, buf_from, page_size);
1800                 if (ret < 0)
1801                         goto out;
1802
1803                 if (!ret)
1804                         break;
1805
1806                 len = ret;
1807
1808                 if (readn(to, buf_to, len) != (int)len)
1809                         goto out;
1810
1811                 if (memcmp(buf_from, buf_to, len))
1812                         goto out;
1813         }
1814
1815         err = 0;
1816 out:
1817         free(buf_to);
1818         free(buf_from);
1819         return err;
1820 }
1821
1822 static int kcore_copy__compare_files(const char *from_filename,
1823                                      const char *to_filename)
1824 {
1825         int from, to, err = -1;
1826
1827         from = open(from_filename, O_RDONLY);
1828         if (from < 0)
1829                 return -1;
1830
1831         to = open(to_filename, O_RDONLY);
1832         if (to < 0)
1833                 goto out_close_from;
1834
1835         err = kcore_copy__compare_fds(from, to);
1836
1837         close(to);
1838 out_close_from:
1839         close(from);
1840         return err;
1841 }
1842
1843 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1844                                     const char *name)
1845 {
1846         char from_filename[PATH_MAX];
1847         char to_filename[PATH_MAX];
1848
1849         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1850         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1851
1852         return kcore_copy__compare_files(from_filename, to_filename);
1853 }
1854
1855 /**
1856  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1857  * @from_dir: from directory
1858  * @to_dir: to directory
1859  *
1860  * This function copies kallsyms, modules and kcore files from one directory to
1861  * another.  kallsyms and modules are copied entirely.  Only code segments are
1862  * copied from kcore.  It is assumed that two segments suffice: one for the
1863  * kernel proper and one for all the modules.  The code segments are determined
1864  * from kallsyms and modules files.  The kernel map starts at _stext or the
1865  * lowest function symbol, and ends at _etext or the highest function symbol.
1866  * The module map starts at the lowest module address and ends at the highest
1867  * module symbol.  Start addresses are rounded down to the nearest page.  End
1868  * addresses are rounded up to the nearest page.  An extra page is added to the
1869  * highest kernel symbol and highest module symbol to, hopefully, encompass that
1870  * symbol too.  Because it contains only code sections, the resulting kcore is
1871  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
1872  * is not the same for the kernel map and the modules map.  That happens because
1873  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
1874  * kallsyms and modules files are compared with their copies to check that
1875  * modules have not been loaded or unloaded while the copies were taking place.
1876  *
1877  * Return: %0 on success, %-1 on failure.
1878  */
1879 int kcore_copy(const char *from_dir, const char *to_dir)
1880 {
1881         struct kcore kcore;
1882         struct kcore extract;
1883         int idx = 0, err = -1;
1884         off_t offset, sz;
1885         struct kcore_copy_info kci = { .stext = 0, };
1886         char kcore_filename[PATH_MAX];
1887         char extract_filename[PATH_MAX];
1888         struct phdr_data *p;
1889
1890         INIT_LIST_HEAD(&kci.phdrs);
1891         INIT_LIST_HEAD(&kci.syms);
1892
1893         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1894                 return -1;
1895
1896         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1897                 goto out_unlink_kallsyms;
1898
1899         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1900         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1901
1902         if (kcore__open(&kcore, kcore_filename))
1903                 goto out_unlink_modules;
1904
1905         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1906                 goto out_kcore_close;
1907
1908         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1909                 goto out_kcore_close;
1910
1911         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1912                 goto out_extract_close;
1913
1914         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1915                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1916         offset = round_up(offset, page_size);
1917
1918         kcore_copy__for_each_phdr(&kci, p) {
1919                 off_t offs = p->rel + offset;
1920
1921                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1922                         goto out_extract_close;
1923         }
1924
1925         sz = kcore__write(&extract);
1926         if (sz < 0 || sz > offset)
1927                 goto out_extract_close;
1928
1929         kcore_copy__for_each_phdr(&kci, p) {
1930                 off_t offs = p->rel + offset;
1931
1932                 if (p->remaps)
1933                         continue;
1934                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1935                         goto out_extract_close;
1936         }
1937
1938         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1939                 goto out_extract_close;
1940
1941         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1942                 goto out_extract_close;
1943
1944         err = 0;
1945
1946 out_extract_close:
1947         kcore__close(&extract);
1948         if (err)
1949                 unlink(extract_filename);
1950 out_kcore_close:
1951         kcore__close(&kcore);
1952 out_unlink_modules:
1953         if (err)
1954                 kcore_copy__unlink(to_dir, "modules");
1955 out_unlink_kallsyms:
1956         if (err)
1957                 kcore_copy__unlink(to_dir, "kallsyms");
1958
1959         kcore_copy__free_phdrs(&kci);
1960         kcore_copy__free_syms(&kci);
1961
1962         return err;
1963 }
1964
1965 int kcore_extract__create(struct kcore_extract *kce)
1966 {
1967         struct kcore kcore;
1968         struct kcore extract;
1969         size_t count = 1;
1970         int idx = 0, err = -1;
1971         off_t offset = page_size, sz;
1972
1973         if (kcore__open(&kcore, kce->kcore_filename))
1974                 return -1;
1975
1976         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1977         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1978                 goto out_kcore_close;
1979
1980         if (kcore__copy_hdr(&kcore, &extract, count))
1981                 goto out_extract_close;
1982
1983         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1984                 goto out_extract_close;
1985
1986         sz = kcore__write(&extract);
1987         if (sz < 0 || sz > offset)
1988                 goto out_extract_close;
1989
1990         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1991                 goto out_extract_close;
1992
1993         err = 0;
1994
1995 out_extract_close:
1996         kcore__close(&extract);
1997         if (err)
1998                 unlink(kce->extract_filename);
1999 out_kcore_close:
2000         kcore__close(&kcore);
2001
2002         return err;
2003 }
2004
2005 void kcore_extract__delete(struct kcore_extract *kce)
2006 {
2007         unlink(kce->extract_filename);
2008 }
2009
2010 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2011
2012 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2013 {
2014         if (!base_off)
2015                 return;
2016
2017         if (tmp->bit32)
2018                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2019                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2020                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2021         else
2022                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2023                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2024                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2025 }
2026
2027 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2028                               GElf_Addr base_off)
2029 {
2030         if (!base_off)
2031                 return;
2032
2033         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2034                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2035         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2036                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2037 }
2038
2039 /**
2040  * populate_sdt_note : Parse raw data and identify SDT note
2041  * @elf: elf of the opened file
2042  * @data: raw data of a section with description offset applied
2043  * @len: note description size
2044  * @type: type of the note
2045  * @sdt_notes: List to add the SDT note
2046  *
2047  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2048  * if its an SDT note, it appends to @sdt_notes list.
2049  */
2050 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2051                              struct list_head *sdt_notes)
2052 {
2053         const char *provider, *name, *args;
2054         struct sdt_note *tmp = NULL;
2055         GElf_Ehdr ehdr;
2056         GElf_Shdr shdr;
2057         int ret = -EINVAL;
2058
2059         union {
2060                 Elf64_Addr a64[NR_ADDR];
2061                 Elf32_Addr a32[NR_ADDR];
2062         } buf;
2063
2064         Elf_Data dst = {
2065                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2066                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2067                 .d_off = 0, .d_align = 0
2068         };
2069         Elf_Data src = {
2070                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2071                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2072                 .d_align = 0
2073         };
2074
2075         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2076         if (!tmp) {
2077                 ret = -ENOMEM;
2078                 goto out_err;
2079         }
2080
2081         INIT_LIST_HEAD(&tmp->note_list);
2082
2083         if (len < dst.d_size + 3)
2084                 goto out_free_note;
2085
2086         /* Translation from file representation to memory representation */
2087         if (gelf_xlatetom(*elf, &dst, &src,
2088                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2089                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2090                 goto out_free_note;
2091         }
2092
2093         /* Populate the fields of sdt_note */
2094         provider = data + dst.d_size;
2095
2096         name = (const char *)memchr(provider, '\0', data + len - provider);
2097         if (name++ == NULL)
2098                 goto out_free_note;
2099
2100         tmp->provider = strdup(provider);
2101         if (!tmp->provider) {
2102                 ret = -ENOMEM;
2103                 goto out_free_note;
2104         }
2105         tmp->name = strdup(name);
2106         if (!tmp->name) {
2107                 ret = -ENOMEM;
2108                 goto out_free_prov;
2109         }
2110
2111         args = memchr(name, '\0', data + len - name);
2112
2113         /*
2114          * There is no argument if:
2115          * - We reached the end of the note;
2116          * - There is not enough room to hold a potential string;
2117          * - The argument string is empty or just contains ':'.
2118          */
2119         if (args == NULL || data + len - args < 2 ||
2120                 args[1] == ':' || args[1] == '\0')
2121                 tmp->args = NULL;
2122         else {
2123                 tmp->args = strdup(++args);
2124                 if (!tmp->args) {
2125                         ret = -ENOMEM;
2126                         goto out_free_name;
2127                 }
2128         }
2129
2130         if (gelf_getclass(*elf) == ELFCLASS32) {
2131                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2132                 tmp->bit32 = true;
2133         } else {
2134                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2135                 tmp->bit32 = false;
2136         }
2137
2138         if (!gelf_getehdr(*elf, &ehdr)) {
2139                 pr_debug("%s : cannot get elf header.\n", __func__);
2140                 ret = -EBADF;
2141                 goto out_free_args;
2142         }
2143
2144         /* Adjust the prelink effect :
2145          * Find out the .stapsdt.base section.
2146          * This scn will help us to handle prelinking (if present).
2147          * Compare the retrieved file offset of the base section with the
2148          * base address in the description of the SDT note. If its different,
2149          * then accordingly, adjust the note location.
2150          */
2151         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2152                 sdt_adjust_loc(tmp, shdr.sh_offset);
2153
2154         /* Adjust reference counter offset */
2155         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2156                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2157
2158         list_add_tail(&tmp->note_list, sdt_notes);
2159         return 0;
2160
2161 out_free_args:
2162         zfree(&tmp->args);
2163 out_free_name:
2164         zfree(&tmp->name);
2165 out_free_prov:
2166         zfree(&tmp->provider);
2167 out_free_note:
2168         free(tmp);
2169 out_err:
2170         return ret;
2171 }
2172
2173 /**
2174  * construct_sdt_notes_list : constructs a list of SDT notes
2175  * @elf : elf to look into
2176  * @sdt_notes : empty list_head
2177  *
2178  * Scans the sections in 'elf' for the section
2179  * .note.stapsdt. It, then calls populate_sdt_note to find
2180  * out the SDT events and populates the 'sdt_notes'.
2181  */
2182 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2183 {
2184         GElf_Ehdr ehdr;
2185         Elf_Scn *scn = NULL;
2186         Elf_Data *data;
2187         GElf_Shdr shdr;
2188         size_t shstrndx, next;
2189         GElf_Nhdr nhdr;
2190         size_t name_off, desc_off, offset;
2191         int ret = 0;
2192
2193         if (gelf_getehdr(elf, &ehdr) == NULL) {
2194                 ret = -EBADF;
2195                 goto out_ret;
2196         }
2197         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2198                 ret = -EBADF;
2199                 goto out_ret;
2200         }
2201
2202         /* Look for the required section */
2203         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2204         if (!scn) {
2205                 ret = -ENOENT;
2206                 goto out_ret;
2207         }
2208
2209         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2210                 ret = -ENOENT;
2211                 goto out_ret;
2212         }
2213
2214         data = elf_getdata(scn, NULL);
2215
2216         /* Get the SDT notes */
2217         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2218                                               &desc_off)) > 0; offset = next) {
2219                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2220                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2221                             sizeof(SDT_NOTE_NAME))) {
2222                         /* Check the type of the note */
2223                         if (nhdr.n_type != SDT_NOTE_TYPE)
2224                                 goto out_ret;
2225
2226                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2227                                                 nhdr.n_descsz, sdt_notes);
2228                         if (ret < 0)
2229                                 goto out_ret;
2230                 }
2231         }
2232         if (list_empty(sdt_notes))
2233                 ret = -ENOENT;
2234
2235 out_ret:
2236         return ret;
2237 }
2238
2239 /**
2240  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2241  * @head : empty list_head
2242  * @target : file to find SDT notes from
2243  *
2244  * This opens the file, initializes
2245  * the ELF and then calls construct_sdt_notes_list.
2246  */
2247 int get_sdt_note_list(struct list_head *head, const char *target)
2248 {
2249         Elf *elf;
2250         int fd, ret;
2251
2252         fd = open(target, O_RDONLY);
2253         if (fd < 0)
2254                 return -EBADF;
2255
2256         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2257         if (!elf) {
2258                 ret = -EBADF;
2259                 goto out_close;
2260         }
2261         ret = construct_sdt_notes_list(elf, head);
2262         elf_end(elf);
2263 out_close:
2264         close(fd);
2265         return ret;
2266 }
2267
2268 /**
2269  * cleanup_sdt_note_list : free the sdt notes' list
2270  * @sdt_notes: sdt notes' list
2271  *
2272  * Free up the SDT notes in @sdt_notes.
2273  * Returns the number of SDT notes free'd.
2274  */
2275 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2276 {
2277         struct sdt_note *tmp, *pos;
2278         int nr_free = 0;
2279
2280         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2281                 list_del_init(&pos->note_list);
2282                 zfree(&pos->name);
2283                 zfree(&pos->provider);
2284                 free(pos);
2285                 nr_free++;
2286         }
2287         return nr_free;
2288 }
2289
2290 /**
2291  * sdt_notes__get_count: Counts the number of sdt events
2292  * @start: list_head to sdt_notes list
2293  *
2294  * Returns the number of SDT notes in a list
2295  */
2296 int sdt_notes__get_count(struct list_head *start)
2297 {
2298         struct sdt_note *sdt_ptr;
2299         int count = 0;
2300
2301         list_for_each_entry(sdt_ptr, start, note_list)
2302                 count++;
2303         return count;
2304 }
2305 #endif
2306
2307 void symbol__elf_init(void)
2308 {
2309         elf_version(EV_CURRENT);
2310 }