tools/perf/util/symbol-elf.c

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