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-ocaml.h"
  16 #include "demangle-java.h"
  17 #include "demangle-rust.h"
  18 #include "machine.h"
  19 #include "vdso.h"
  20 #include "debug.h"
  21 #include "util/copyfile.h"
  22 #include <linux/ctype.h>
  23 #include <linux/kernel.h>
  24 #include <linux/zalloc.h>
  25 #include <symbol/kallsyms.h>
  26 #include <internal/lib.h>
  27
  28 #ifndef EM_AARCH64
  29 #define EM_AARCH64      183  /* ARM 64 bit */
  30 #endif
  31
  32 #ifndef ELF32_ST_VISIBILITY
  33 #define ELF32_ST_VISIBILITY(o)  ((o) & 0x03)
  34 #endif
  35
  36 /* For ELF64 the definitions are the same.  */
  37 #ifndef ELF64_ST_VISIBILITY
  38 #define ELF64_ST_VISIBILITY(o)  ELF32_ST_VISIBILITY (o)
  39 #endif
  40
  41 /* How to extract information held in the st_other field.  */
  42 #ifndef GELF_ST_VISIBILITY
  43 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
  44 #endif
  45
  46 typedef Elf64_Nhdr GElf_Nhdr;
  47
  48 #ifndef DMGL_PARAMS
  49 #define DMGL_NO_OPTS     0              /* For readability... */
  50 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
  51 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
  52 #endif
  53
  54 #ifdef HAVE_LIBBFD_SUPPORT
  55 #define PACKAGE 'perf'
  56 #include <bfd.h>
  57 #else
  58 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
  59 extern char *cplus_demangle(const char *, int);
  60
  61 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
  62 {
  63         return cplus_demangle(c, i);
  64 }
  65 #else
  66 #ifdef NO_DEMANGLE
  67 static inline char *bfd_demangle(void __maybe_unused *v,
  68                                  const char __maybe_unused *c,
  69                                  int __maybe_unused i)
  70 {
  71         return NULL;
  72 }
  73 #endif
  74 #endif
  75 #endif
  76
  77 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
  78 static int elf_getphdrnum(Elf *elf, size_t *dst)
  79 {
  80         GElf_Ehdr gehdr;
  81         GElf_Ehdr *ehdr;
  82
  83         ehdr = gelf_getehdr(elf, &gehdr);
  84         if (!ehdr)
  85                 return -1;
  86
  87         *dst = ehdr->e_phnum;
  88
  89         return 0;
  90 }
  91 #endif
  92
  93 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
  94 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
  95 {
  96         pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
  97         return -1;
  98 }
  99 #endif
 100
 101 #ifndef NT_GNU_BUILD_ID
 102 #define NT_GNU_BUILD_ID 3
 103 #endif
 104
 105 /**
 106  * elf_symtab__for_each_symbol - iterate thru all the symbols
 107  *
 108  * @syms: struct elf_symtab instance to iterate
 109  * @idx: uint32_t idx
 110  * @sym: GElf_Sym iterator
 111  */
 112 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
 113         for (idx = 0, gelf_getsym(syms, idx, &sym);\
 114              idx < nr_syms; \
 115              idx++, gelf_getsym(syms, idx, &sym))
 116
 117 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
 118 {
 119         return GELF_ST_TYPE(sym->st_info);
 120 }
 121
 122 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
 123 {
 124         return GELF_ST_VISIBILITY(sym->st_other);
 125 }
 126
 127 #ifndef STT_GNU_IFUNC
 128 #define STT_GNU_IFUNC 10
 129 #endif
 130
 131 static inline int elf_sym__is_function(const GElf_Sym *sym)
 132 {
 133         return (elf_sym__type(sym) == STT_FUNC ||
 134                 elf_sym__type(sym) == STT_GNU_IFUNC) &&
 135                sym->st_name != 0 &&
 136                sym->st_shndx != SHN_UNDEF;
 137 }
 138
 139 static inline bool elf_sym__is_object(const GElf_Sym *sym)
 140 {
 141         return elf_sym__type(sym) == STT_OBJECT &&
 142                 sym->st_name != 0 &&
 143                 sym->st_shndx != SHN_UNDEF;
 144 }
 145
 146 static inline int elf_sym__is_label(const GElf_Sym *sym)
 147 {
 148         return elf_sym__type(sym) == STT_NOTYPE &&
 149                 sym->st_name != 0 &&
 150                 sym->st_shndx != SHN_UNDEF &&
 151                 sym->st_shndx != SHN_ABS &&
 152                 elf_sym__visibility(sym) != STV_HIDDEN &&
 153                 elf_sym__visibility(sym) != STV_INTERNAL;
 154 }
 155
 156 static bool elf_sym__filter(GElf_Sym *sym)
 157 {
 158         return elf_sym__is_function(sym) || elf_sym__is_object(sym);
 159 }
 160
 161 static inline const char *elf_sym__name(const GElf_Sym *sym,
 162                                         const Elf_Data *symstrs)
 163 {
 164         return symstrs->d_buf + sym->st_name;
 165 }
 166
 167 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
 168                                         const Elf_Data *secstrs)
 169 {
 170         return secstrs->d_buf + shdr->sh_name;
 171 }
 172
 173 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
 174                                         const Elf_Data *secstrs)
 175 {
 176         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
 177 }
 178
 179 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
 180                                     const Elf_Data *secstrs)
 181 {
 182         return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
 183 }
 184
 185 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
 186 {
 187         return elf_sec__is_text(shdr, secstrs) ||
 188                elf_sec__is_data(shdr, secstrs);
 189 }
 190
 191 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
 192 {
 193         Elf_Scn *sec = NULL;
 194         GElf_Shdr shdr;
 195         size_t cnt = 1;
 196
 197         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 198                 gelf_getshdr(sec, &shdr);
 199
 200                 if ((addr >= shdr.sh_addr) &&
 201                     (addr < (shdr.sh_addr + shdr.sh_size)))
 202                         return cnt;
 203
 204                 ++cnt;
 205         }
 206
 207         return -1;
 208 }
 209
 210 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
 211                              GElf_Shdr *shp, const char *name, size_t *idx)
 212 {
 213         Elf_Scn *sec = NULL;
 214         size_t cnt = 1;
 215
 216         /* Elf is corrupted/truncated, avoid calling elf_strptr. */
 217         if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
 218                 return NULL;
 219
 220         while ((sec = elf_nextscn(elf, sec)) != NULL) {
 221                 char *str;
 222
 223                 gelf_getshdr(sec, shp);
 224                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
 225                 if (str && !strcmp(name, str)) {
 226                         if (idx)
 227                                 *idx = cnt;
 228                         return sec;
 229                 }
 230                 ++cnt;
 231         }
 232
 233         return NULL;
 234 }
 235
 236 static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)
 237 {
 238         size_t i, phdrnum;
 239         u64 sz;
 240
 241         if (elf_getphdrnum(elf, &phdrnum))
 242                 return -1;
 243
 244         for (i = 0; i < phdrnum; i++) {
 245                 if (gelf_getphdr(elf, i, phdr) == NULL)
 246                         return -1;
 247
 248                 if (phdr->p_type != PT_LOAD)
 249                         continue;
 250
 251                 sz = max(phdr->p_memsz, phdr->p_filesz);
 252                 if (!sz)
 253                         continue;
 254
 255                 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))
 256                         return 0;
 257         }
 258
 259         /* Not found any valid program header */
 260         return -1;
 261 }
 262
 263 static bool want_demangle(bool is_kernel_sym)
 264 {
 265         return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 266 }
 267
 268 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 269 {
 270         int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
 271         char *demangled = NULL;
 272
 273         /*
 274          * We need to figure out if the object was created from C++ sources
 275          * DWARF DW_compile_unit has this, but we don't always have access
 276          * to it...
 277          */
 278         if (!want_demangle(dso->kernel || kmodule))
 279             return demangled;
 280
 281         demangled = bfd_demangle(NULL, elf_name, demangle_flags);
 282         if (demangled == NULL) {
 283                 demangled = ocaml_demangle_sym(elf_name);
 284                 if (demangled == NULL) {
 285                         demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
 286                 }
 287         }
 288         else if (rust_is_mangled(demangled))
 289                 /*
 290                     * Input to Rust demangling is the BFD-demangled
 291                     * name which it Rust-demangles in place.
 292                     */
 293                 rust_demangle_sym(demangled);
 294
 295         return demangled;
 296 }
 297
 298 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
 299         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
 300              idx < nr_entries; \
 301              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
 302
 303 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
 304         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
 305              idx < nr_entries; \
 306              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
 307
 308 /*
 309  * We need to check if we have a .dynsym, so that we can handle the
 310  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
 311  * .dynsym or .symtab).
 312  * And always look at the original dso, not at debuginfo packages, that
 313  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
 314  */
 315 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
 316 {
 317         uint32_t nr_rel_entries, idx;
 318         GElf_Sym sym;
 319         u64 plt_offset, plt_header_size, plt_entry_size;
 320         GElf_Shdr shdr_plt;
 321         struct symbol *f;
 322         GElf_Shdr shdr_rel_plt, shdr_dynsym;
 323         Elf_Data *reldata, *syms, *symstrs;
 324         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
 325         size_t dynsym_idx;
 326         GElf_Ehdr ehdr;
 327         char sympltname[1024];
 328         Elf *elf;
 329         int nr = 0, symidx, err = 0;
 330
 331         if (!ss->dynsym)
 332                 return 0;
 333
 334         elf = ss->elf;
 335         ehdr = ss->ehdr;
 336
 337         scn_dynsym = ss->dynsym;
 338         shdr_dynsym = ss->dynshdr;
 339         dynsym_idx = ss->dynsym_idx;
 340
 341         if (scn_dynsym == NULL)
 342                 goto out_elf_end;
 343
 344         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 345                                           ".rela.plt", NULL);
 346         if (scn_plt_rel == NULL) {
 347                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
 348                                                   ".rel.plt", NULL);
 349                 if (scn_plt_rel == NULL)
 350                         goto out_elf_end;
 351         }
 352
 353         err = -1;
 354
 355         if (shdr_rel_plt.sh_link != dynsym_idx)
 356                 goto out_elf_end;
 357
 358         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
 359                 goto out_elf_end;
 360
 361         /*
 362          * Fetch the relocation section to find the idxes to the GOT
 363          * and the symbols in the .dynsym they refer to.
 364          */
 365         reldata = elf_getdata(scn_plt_rel, NULL);
 366         if (reldata == NULL)
 367                 goto out_elf_end;
 368
 369         syms = elf_getdata(scn_dynsym, NULL);
 370         if (syms == NULL)
 371                 goto out_elf_end;
 372
 373         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
 374         if (scn_symstrs == NULL)
 375                 goto out_elf_end;
 376
 377         symstrs = elf_getdata(scn_symstrs, NULL);
 378         if (symstrs == NULL)
 379                 goto out_elf_end;
 380
 381         if (symstrs->d_size == 0)
 382                 goto out_elf_end;
 383
 384         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
 385         plt_offset = shdr_plt.sh_offset;
 386         switch (ehdr.e_machine) {
 387                 case EM_ARM:
 388                         plt_header_size = 20;
 389                         plt_entry_size = 12;
 390                         break;
 391
 392                 case EM_AARCH64:
 393                         plt_header_size = 32;
 394                         plt_entry_size = 16;
 395                         break;
 396
 397                 case EM_SPARC:
 398                         plt_header_size = 48;
 399                         plt_entry_size = 12;
 400                         break;
 401
 402                 case EM_SPARCV9:
 403                         plt_header_size = 128;
 404                         plt_entry_size = 32;
 405                         break;
 406
 407                 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
 408                         plt_header_size = shdr_plt.sh_entsize;
 409                         plt_entry_size = shdr_plt.sh_entsize;
 410                         break;
 411         }
 412         plt_offset += plt_header_size;
 413
 414         if (shdr_rel_plt.sh_type == SHT_RELA) {
 415                 GElf_Rela pos_mem, *pos;
 416
 417                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
 418                                            nr_rel_entries) {
 419                         const char *elf_name = NULL;
 420                         char *demangled = NULL;
 421                         symidx = GELF_R_SYM(pos->r_info);
 422                         gelf_getsym(syms, symidx, &sym);
 423
 424                         elf_name = elf_sym__name(&sym, symstrs);
 425                         demangled = demangle_sym(dso, 0, elf_name);
 426                         if (demangled != NULL)
 427                                 elf_name = demangled;
 428                         snprintf(sympltname, sizeof(sympltname),
 429                                  "%s@plt", elf_name);
 430                         free(demangled);
 431
 432                         f = symbol__new(plt_offset, plt_entry_size,
 433                                         STB_GLOBAL, STT_FUNC, sympltname);
 434                         if (!f)
 435                                 goto out_elf_end;
 436
 437                         plt_offset += plt_entry_size;
 438                         symbols__insert(&dso->symbols, f);
 439                         ++nr;
 440                 }
 441         } else if (shdr_rel_plt.sh_type == SHT_REL) {
 442                 GElf_Rel pos_mem, *pos;
 443                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
 444                                           nr_rel_entries) {
 445                         const char *elf_name = NULL;
 446                         char *demangled = NULL;
 447                         symidx = GELF_R_SYM(pos->r_info);
 448                         gelf_getsym(syms, symidx, &sym);
 449
 450                         elf_name = elf_sym__name(&sym, symstrs);
 451                         demangled = demangle_sym(dso, 0, elf_name);
 452                         if (demangled != NULL)
 453                                 elf_name = demangled;
 454                         snprintf(sympltname, sizeof(sympltname),
 455                                  "%s@plt", elf_name);
 456                         free(demangled);
 457
 458                         f = symbol__new(plt_offset, plt_entry_size,
 459                                         STB_GLOBAL, STT_FUNC, sympltname);
 460                         if (!f)
 461                                 goto out_elf_end;
 462
 463                         plt_offset += plt_entry_size;
 464                         symbols__insert(&dso->symbols, f);
 465                         ++nr;
 466                 }
 467         }
 468
 469         err = 0;
 470 out_elf_end:
 471         if (err == 0)
 472                 return nr;
 473         pr_debug("%s: problems reading %s PLT info.\n",
 474                  __func__, dso->long_name);
 475         return 0;
 476 }
 477
 478 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
 479 {
 480         return demangle_sym(dso, kmodule, elf_name);
 481 }
 482
 483 /*
 484  * Align offset to 4 bytes as needed for note name and descriptor data.
 485  */
 486 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
 487
 488 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
 489 {
 490         int err = -1;
 491         GElf_Ehdr ehdr;
 492         GElf_Shdr shdr;
 493         Elf_Data *data;
 494         Elf_Scn *sec;
 495         Elf_Kind ek;
 496         void *ptr;
 497
 498         if (size < BUILD_ID_SIZE)
 499                 goto out;
 500
 501         ek = elf_kind(elf);
 502         if (ek != ELF_K_ELF)
 503                 goto out;
 504
 505         if (gelf_getehdr(elf, &ehdr) == NULL) {
 506                 pr_err("%s: cannot get elf header.\n", __func__);
 507                 goto out;
 508         }
 509
 510         /*
 511          * Check following sections for notes:
 512          *   '.note.gnu.build-id'
 513          *   '.notes'
 514          *   '.note' (VDSO specific)
 515          */
 516         do {
 517                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 518                                           ".note.gnu.build-id", NULL);
 519                 if (sec)
 520                         break;
 521
 522                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 523                                           ".notes", NULL);
 524                 if (sec)
 525                         break;
 526
 527                 sec = elf_section_by_name(elf, &ehdr, &shdr,
 528                                           ".note", NULL);
 529                 if (sec)
 530                         break;
 531
 532                 return err;
 533
 534         } while (0);
 535
 536         data = elf_getdata(sec, NULL);
 537         if (data == NULL)
 538                 goto out;
 539
 540         ptr = data->d_buf;
 541         while (ptr < (data->d_buf + data->d_size)) {
 542                 GElf_Nhdr *nhdr = ptr;
 543                 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
 544                        descsz = NOTE_ALIGN(nhdr->n_descsz);
 545                 const char *name;
 546
 547                 ptr += sizeof(*nhdr);
 548                 name = ptr;
 549                 ptr += namesz;
 550                 if (nhdr->n_type == NT_GNU_BUILD_ID &&
 551                     nhdr->n_namesz == sizeof("GNU")) {
 552                         if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
 553                                 size_t sz = min(size, descsz);
 554                                 memcpy(bf, ptr, sz);
 555                                 memset(bf + sz, 0, size - sz);
 556                                 err = descsz;
 557                                 break;
 558                         }
 559                 }
 560                 ptr += descsz;
 561         }
 562
 563 out:
 564         return err;
 565 }
 566
 567 #ifdef HAVE_LIBBFD_BUILDID_SUPPORT
 568
 569 static int read_build_id(const char *filename, struct build_id *bid)
 570 {
 571         size_t size = sizeof(bid->data);
 572         int err = -1;
 573         bfd *abfd;
 574
 575         abfd = bfd_openr(filename, NULL);
 576         if (!abfd)
 577                 return -1;
 578
 579         if (!bfd_check_format(abfd, bfd_object)) {
 580                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 581                 goto out_close;
 582         }
 583
 584         if (!abfd->build_id || abfd->build_id->size > size)
 585                 goto out_close;
 586
 587         memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);
 588         memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);
 589         err = bid->size = abfd->build_id->size;
 590
 591 out_close:
 592         bfd_close(abfd);
 593         return err;
 594 }
 595
 596 #else // HAVE_LIBBFD_BUILDID_SUPPORT
 597
 598 static int read_build_id(const char *filename, struct build_id *bid)
 599 {
 600         size_t size = sizeof(bid->data);
 601         int fd, err = -1;
 602         Elf *elf;
 603
 604         if (size < BUILD_ID_SIZE)
 605                 goto out;
 606
 607         fd = open(filename, O_RDONLY);
 608         if (fd < 0)
 609                 goto out;
 610
 611         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 612         if (elf == NULL) {
 613                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 614                 goto out_close;
 615         }
 616
 617         err = elf_read_build_id(elf, bid->data, size);
 618         if (err > 0)
 619                 bid->size = err;
 620
 621         elf_end(elf);
 622 out_close:
 623         close(fd);
 624 out:
 625         return err;
 626 }
 627
 628 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 629
 630 int filename__read_build_id(const char *filename, struct build_id *bid)
 631 {
 632         struct kmod_path m = { .name = NULL, };
 633         char path[PATH_MAX];
 634         int err;
 635
 636         if (!filename)
 637                 return -EFAULT;
 638
 639         err = kmod_path__parse(&m, filename);
 640         if (err)
 641                 return -1;
 642
 643         if (m.comp) {
 644                 int error = 0, fd;
 645
 646                 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
 647                 if (fd < 0) {
 648                         pr_debug("Failed to decompress (error %d) %s\n",
 649                                  error, filename);
 650                         return -1;
 651                 }
 652                 close(fd);
 653                 filename = path;
 654         }
 655
 656         err = read_build_id(filename, bid);
 657
 658         if (m.comp)
 659                 unlink(filename);
 660         return err;
 661 }
 662
 663 int sysfs__read_build_id(const char *filename, struct build_id *bid)
 664 {
 665         size_t size = sizeof(bid->data);
 666         int fd, err = -1;
 667
 668         fd = open(filename, O_RDONLY);
 669         if (fd < 0)
 670                 goto out;
 671
 672         while (1) {
 673                 char bf[BUFSIZ];
 674                 GElf_Nhdr nhdr;
 675                 size_t namesz, descsz;
 676
 677                 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
 678                         break;
 679
 680                 namesz = NOTE_ALIGN(nhdr.n_namesz);
 681                 descsz = NOTE_ALIGN(nhdr.n_descsz);
 682                 if (nhdr.n_type == NT_GNU_BUILD_ID &&
 683                     nhdr.n_namesz == sizeof("GNU")) {
 684                         if (read(fd, bf, namesz) != (ssize_t)namesz)
 685                                 break;
 686                         if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 687                                 size_t sz = min(descsz, size);
 688                                 if (read(fd, bid->data, sz) == (ssize_t)sz) {
 689                                         memset(bid->data + sz, 0, size - sz);
 690                                         bid->size = sz;
 691                                         err = 0;
 692                                         break;
 693                                 }
 694                         } else if (read(fd, bf, descsz) != (ssize_t)descsz)
 695                                 break;
 696                 } else {
 697                         int n = namesz + descsz;
 698
 699                         if (n > (int)sizeof(bf)) {
 700                                 n = sizeof(bf);
 701                                 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
 702                                          __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
 703                         }
 704                         if (read(fd, bf, n) != n)
 705                                 break;
 706                 }
 707         }
 708         close(fd);
 709 out:
 710         return err;
 711 }
 712
 713 #ifdef HAVE_LIBBFD_SUPPORT
 714
 715 int filename__read_debuglink(const char *filename, char *debuglink,
 716                              size_t size)
 717 {
 718         int err = -1;
 719         asection *section;
 720         bfd *abfd;
 721
 722         abfd = bfd_openr(filename, NULL);
 723         if (!abfd)
 724                 return -1;
 725
 726         if (!bfd_check_format(abfd, bfd_object)) {
 727                 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);
 728                 goto out_close;
 729         }
 730
 731         section = bfd_get_section_by_name(abfd, ".gnu_debuglink");
 732         if (!section)
 733                 goto out_close;
 734
 735         if (section->size > size)
 736                 goto out_close;
 737
 738         if (!bfd_get_section_contents(abfd, section, debuglink, 0,
 739                                       section->size))
 740                 goto out_close;
 741
 742         err = 0;
 743
 744 out_close:
 745         bfd_close(abfd);
 746         return err;
 747 }
 748
 749 #else
 750
 751 int filename__read_debuglink(const char *filename, char *debuglink,
 752                              size_t size)
 753 {
 754         int fd, err = -1;
 755         Elf *elf;
 756         GElf_Ehdr ehdr;
 757         GElf_Shdr shdr;
 758         Elf_Data *data;
 759         Elf_Scn *sec;
 760         Elf_Kind ek;
 761
 762         fd = open(filename, O_RDONLY);
 763         if (fd < 0)
 764                 goto out;
 765
 766         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 767         if (elf == NULL) {
 768                 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
 769                 goto out_close;
 770         }
 771
 772         ek = elf_kind(elf);
 773         if (ek != ELF_K_ELF)
 774                 goto out_elf_end;
 775
 776         if (gelf_getehdr(elf, &ehdr) == NULL) {
 777                 pr_err("%s: cannot get elf header.\n", __func__);
 778                 goto out_elf_end;
 779         }
 780
 781         sec = elf_section_by_name(elf, &ehdr, &shdr,
 782                                   ".gnu_debuglink", NULL);
 783         if (sec == NULL)
 784                 goto out_elf_end;
 785
 786         data = elf_getdata(sec, NULL);
 787         if (data == NULL)
 788                 goto out_elf_end;
 789
 790         /* the start of this section is a zero-terminated string */
 791         strncpy(debuglink, data->d_buf, size);
 792
 793         err = 0;
 794
 795 out_elf_end:
 796         elf_end(elf);
 797 out_close:
 798         close(fd);
 799 out:
 800         return err;
 801 }
 802
 803 #endif
 804
 805 static int dso__swap_init(struct dso *dso, unsigned char eidata)
 806 {
 807         static unsigned int const endian = 1;
 808
 809         dso->needs_swap = DSO_SWAP__NO;
 810
 811         switch (eidata) {
 812         case ELFDATA2LSB:
 813                 /* We are big endian, DSO is little endian. */
 814                 if (*(unsigned char const *)&endian != 1)
 815                         dso->needs_swap = DSO_SWAP__YES;
 816                 break;
 817
 818         case ELFDATA2MSB:
 819                 /* We are little endian, DSO is big endian. */
 820                 if (*(unsigned char const *)&endian != 0)
 821                         dso->needs_swap = DSO_SWAP__YES;
 822                 break;
 823
 824         default:
 825                 pr_err("unrecognized DSO data encoding %d\n", eidata);
 826                 return -EINVAL;
 827         }
 828
 829         return 0;
 830 }
 831
 832 bool symsrc__possibly_runtime(struct symsrc *ss)
 833 {
 834         return ss->dynsym || ss->opdsec;
 835 }
 836
 837 bool symsrc__has_symtab(struct symsrc *ss)
 838 {
 839         return ss->symtab != NULL;
 840 }
 841
 842 void symsrc__destroy(struct symsrc *ss)
 843 {
 844         zfree(&ss->name);
 845         elf_end(ss->elf);
 846         close(ss->fd);
 847 }
 848
 849 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 850 {
 851         /*
 852          * Usually vmlinux is an ELF file with type ET_EXEC for most
 853          * architectures; except Arm64 kernel is linked with option
 854          * '-share', so need to check type ET_DYN.
 855          */
 856         return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
 857                ehdr.e_type == ET_DYN;
 858 }
 859
 860 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 861                  enum dso_binary_type type)
 862 {
 863         GElf_Ehdr ehdr;
 864         Elf *elf;
 865         int fd;
 866
 867         if (dso__needs_decompress(dso)) {
 868                 fd = dso__decompress_kmodule_fd(dso, name);
 869                 if (fd < 0)
 870                         return -1;
 871
 872                 type = dso->symtab_type;
 873         } else {
 874                 fd = open(name, O_RDONLY);
 875                 if (fd < 0) {
 876                         dso->load_errno = errno;
 877                         return -1;
 878                 }
 879         }
 880
 881         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
 882         if (elf == NULL) {
 883                 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
 884                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 885                 goto out_close;
 886         }
 887
 888         if (gelf_getehdr(elf, &ehdr) == NULL) {
 889                 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
 890                 pr_debug("%s: cannot get elf header.\n", __func__);
 891                 goto out_elf_end;
 892         }
 893
 894         if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
 895                 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
 896                 goto out_elf_end;
 897         }
 898
 899         /* Always reject images with a mismatched build-id: */
 900         if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
 901                 u8 build_id[BUILD_ID_SIZE];
 902                 struct build_id bid;
 903                 int size;
 904
 905                 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);
 906                 if (size <= 0) {
 907                         dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
 908                         goto out_elf_end;
 909                 }
 910
 911                 build_id__init(&bid, build_id, size);
 912                 if (!dso__build_id_equal(dso, &bid)) {
 913                         pr_debug("%s: build id mismatch for %s.\n", __func__, name);
 914                         dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
 915                         goto out_elf_end;
 916                 }
 917         }
 918
 919         ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
 920
 921         ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
 922                         NULL);
 923         if (ss->symshdr.sh_type != SHT_SYMTAB)
 924                 ss->symtab = NULL;
 925
 926         ss->dynsym_idx = 0;
 927         ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
 928                         &ss->dynsym_idx);
 929         if (ss->dynshdr.sh_type != SHT_DYNSYM)
 930                 ss->dynsym = NULL;
 931
 932         ss->opdidx = 0;
 933         ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
 934                         &ss->opdidx);
 935         if (ss->opdshdr.sh_type != SHT_PROGBITS)
 936                 ss->opdsec = NULL;
 937
 938         if (dso->kernel == DSO_SPACE__USER)
 939                 ss->adjust_symbols = true;
 940         else
 941                 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 942
 943         ss->name   = strdup(name);
 944         if (!ss->name) {
 945                 dso->load_errno = errno;
 946                 goto out_elf_end;
 947         }
 948
 949         ss->elf    = elf;
 950         ss->fd     = fd;
 951         ss->ehdr   = ehdr;
 952         ss->type   = type;
 953
 954         return 0;
 955
 956 out_elf_end:
 957         elf_end(elf);
 958 out_close:
 959         close(fd);
 960         return -1;
 961 }
 962
 963 /**
 964  * ref_reloc_sym_not_found - has kernel relocation symbol been found.
 965  * @kmap: kernel maps and relocation reference symbol
 966  *
 967  * This function returns %true if we are dealing with the kernel maps and the
 968  * relocation reference symbol has not yet been found.  Otherwise %false is
 969  * returned.
 970  */
 971 static bool ref_reloc_sym_not_found(struct kmap *kmap)
 972 {
 973         return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
 974                !kmap->ref_reloc_sym->unrelocated_addr;
 975 }
 976
 977 /**
 978  * ref_reloc - kernel relocation offset.
 979  * @kmap: kernel maps and relocation reference symbol
 980  *
 981  * This function returns the offset of kernel addresses as determined by using
 982  * the relocation reference symbol i.e. if the kernel has not been relocated
 983  * then the return value is zero.
 984  */
 985 static u64 ref_reloc(struct kmap *kmap)
 986 {
 987         if (kmap && kmap->ref_reloc_sym &&
 988             kmap->ref_reloc_sym->unrelocated_addr)
 989                 return kmap->ref_reloc_sym->addr -
 990                        kmap->ref_reloc_sym->unrelocated_addr;
 991         return 0;
 992 }
 993
 994 void __weak arch__sym_update(struct symbol *s __maybe_unused,
 995                 GElf_Sym *sym __maybe_unused) { }
 996
 997 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 998                                       GElf_Sym *sym, GElf_Shdr *shdr,
 999                                       struct maps *kmaps, struct kmap *kmap,
1000                                       struct dso **curr_dsop, struct map **curr_mapp,
1001                                       const char *section_name,
1002                                       bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
1003 {
1004         struct dso *curr_dso = *curr_dsop;
1005         struct map *curr_map;
1006         char dso_name[PATH_MAX];
1007
1008         /* Adjust symbol to map to file offset */
1009         if (adjust_kernel_syms)
1010                 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
1011
1012         if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
1013                 return 0;
1014
1015         if (strcmp(section_name, ".text") == 0) {
1016                 /*
1017                  * The initial kernel mapping is based on
1018                  * kallsyms and identity maps.  Overwrite it to
1019                  * map to the kernel dso.
1020                  */
1021                 if (*remap_kernel && dso->kernel && !kmodule) {
1022                         *remap_kernel = false;
1023                         map->start = shdr->sh_addr + ref_reloc(kmap);
1024                         map->end = map->start + shdr->sh_size;
1025                         map->pgoff = shdr->sh_offset;
1026                         map->map_ip = map__map_ip;
1027                         map->unmap_ip = map__unmap_ip;
1028                         /* Ensure maps are correctly ordered */
1029                         if (kmaps) {
1030                                 map__get(map);
1031                                 maps__remove(kmaps, map);
1032                                 maps__insert(kmaps, map);
1033                                 map__put(map);
1034                         }
1035                 }
1036
1037                 /*
1038                  * The initial module mapping is based on
1039                  * /proc/modules mapped to offset zero.
1040                  * Overwrite it to map to the module dso.
1041                  */
1042                 if (*remap_kernel && kmodule) {
1043                         *remap_kernel = false;
1044                         map->pgoff = shdr->sh_offset;
1045                 }
1046
1047                 *curr_mapp = map;
1048                 *curr_dsop = dso;
1049                 return 0;
1050         }
1051
1052         if (!kmap)
1053                 return 0;
1054
1055         snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
1056
1057         curr_map = maps__find_by_name(kmaps, dso_name);
1058         if (curr_map == NULL) {
1059                 u64 start = sym->st_value;
1060
1061                 if (kmodule)
1062                         start += map->start + shdr->sh_offset;
1063
1064                 curr_dso = dso__new(dso_name);
1065                 if (curr_dso == NULL)
1066                         return -1;
1067                 curr_dso->kernel = dso->kernel;
1068                 curr_dso->long_name = dso->long_name;
1069                 curr_dso->long_name_len = dso->long_name_len;
1070                 curr_map = map__new2(start, curr_dso);
1071                 dso__put(curr_dso);
1072                 if (curr_map == NULL)
1073                         return -1;
1074
1075                 if (curr_dso->kernel)
1076                         map__kmap(curr_map)->kmaps = kmaps;
1077
1078                 if (adjust_kernel_syms) {
1079                         curr_map->start  = shdr->sh_addr + ref_reloc(kmap);
1080                         curr_map->end    = curr_map->start + shdr->sh_size;
1081                         curr_map->pgoff  = shdr->sh_offset;
1082                 } else {
1083                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
1084                 }
1085                 curr_dso->symtab_type = dso->symtab_type;
1086                 maps__insert(kmaps, curr_map);
1087                 /*
1088                  * Add it before we drop the reference to curr_map, i.e. while
1089                  * we still are sure to have a reference to this DSO via
1090                  * *curr_map->dso.
1091                  */
1092                 dsos__add(&kmaps->machine->dsos, curr_dso);
1093                 /* kmaps already got it */
1094                 map__put(curr_map);
1095                 dso__set_loaded(curr_dso);
1096                 *curr_mapp = curr_map;
1097                 *curr_dsop = curr_dso;
1098         } else
1099                 *curr_dsop = curr_map->dso;
1100
1101         return 0;
1102 }
1103
1104 static int
1105 dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1106                        struct symsrc *runtime_ss, int kmodule, int dynsym)
1107 {
1108         struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
1109         struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
1110         struct map *curr_map = map;
1111         struct dso *curr_dso = dso;
1112         Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
1113         uint32_t nr_syms;
1114         int err = -1;
1115         uint32_t idx;
1116         GElf_Ehdr ehdr;
1117         GElf_Shdr shdr;
1118         GElf_Shdr tshdr;
1119         Elf_Data *syms, *opddata = NULL;
1120         GElf_Sym sym;
1121         Elf_Scn *sec, *sec_strndx;
1122         Elf *elf;
1123         int nr = 0;
1124         bool remap_kernel = false, adjust_kernel_syms = false;
1125
1126         if (kmap && !kmaps)
1127                 return -1;
1128
1129         elf = syms_ss->elf;
1130         ehdr = syms_ss->ehdr;
1131         if (dynsym) {
1132                 sec  = syms_ss->dynsym;
1133                 shdr = syms_ss->dynshdr;
1134         } else {
1135                 sec =  syms_ss->symtab;
1136                 shdr = syms_ss->symshdr;
1137         }
1138
1139         if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1140                                 ".text", NULL))
1141                 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1142
1143         if (runtime_ss->opdsec)
1144                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1145
1146         syms = elf_getdata(sec, NULL);
1147         if (syms == NULL)
1148                 goto out_elf_end;
1149
1150         sec = elf_getscn(elf, shdr.sh_link);
1151         if (sec == NULL)
1152                 goto out_elf_end;
1153
1154         symstrs = elf_getdata(sec, NULL);
1155         if (symstrs == NULL)
1156                 goto out_elf_end;
1157
1158         sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1159         if (sec_strndx == NULL)
1160                 goto out_elf_end;
1161
1162         secstrs_run = elf_getdata(sec_strndx, NULL);
1163         if (secstrs_run == NULL)
1164                 goto out_elf_end;
1165
1166         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
1167         if (sec_strndx == NULL)
1168                 goto out_elf_end;
1169
1170         secstrs_sym = elf_getdata(sec_strndx, NULL);
1171         if (secstrs_sym == NULL)
1172                 goto out_elf_end;
1173
1174         nr_syms = shdr.sh_size / shdr.sh_entsize;
1175
1176         memset(&sym, 0, sizeof(sym));
1177
1178         /*
1179          * The kernel relocation symbol is needed in advance in order to adjust
1180          * kernel maps correctly.
1181          */
1182         if (ref_reloc_sym_not_found(kmap)) {
1183                 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1184                         const char *elf_name = elf_sym__name(&sym, symstrs);
1185
1186                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1187                                 continue;
1188                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1189                         map->reloc = kmap->ref_reloc_sym->addr -
1190                                      kmap->ref_reloc_sym->unrelocated_addr;
1191                         break;
1192                 }
1193         }
1194
1195         /*
1196          * Handle any relocation of vdso necessary because older kernels
1197          * attempted to prelink vdso to its virtual address.
1198          */
1199         if (dso__is_vdso(dso))
1200                 map->reloc = map->start - dso->text_offset;
1201
1202         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1203         /*
1204          * Initial kernel and module mappings do not map to the dso.
1205          * Flag the fixups.
1206          */
1207         if (dso->kernel) {
1208                 remap_kernel = true;
1209                 adjust_kernel_syms = dso->adjust_symbols;
1210         }
1211         elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1212                 struct symbol *f;
1213                 const char *elf_name = elf_sym__name(&sym, symstrs);
1214                 char *demangled = NULL;
1215                 int is_label = elf_sym__is_label(&sym);
1216                 const char *section_name;
1217                 bool used_opd = false;
1218
1219                 if (!is_label && !elf_sym__filter(&sym))
1220                         continue;
1221
1222                 /* Reject ARM ELF "mapping symbols": these aren't unique and
1223                  * don't identify functions, so will confuse the profile
1224                  * output: */
1225                 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1226                         if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1227                             && (elf_name[2] == '\0' || elf_name[2] == '.'))
1228                                 continue;
1229                 }
1230
1231                 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1232                         u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1233                         u64 *opd = opddata->d_buf + offset;
1234                         sym.st_value = DSO__SWAP(dso, u64, *opd);
1235                         sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1236                                         sym.st_value);
1237                         used_opd = true;
1238                 }
1239
1240                 /*
1241                  * When loading symbols in a data mapping, ABS symbols (which
1242                  * has a value of SHN_ABS in its st_shndx) failed at
1243                  * elf_getscn().  And it marks the loading as a failure so
1244                  * already loaded symbols cannot be fixed up.
1245                  *
1246                  * I'm not sure what should be done. Just ignore them for now.
1247                  * - Namhyung Kim
1248                  */
1249                 if (sym.st_shndx == SHN_ABS)
1250                         continue;
1251
1252                 sec = elf_getscn(syms_ss->elf, sym.st_shndx);
1253                 if (!sec)
1254                         goto out_elf_end;
1255
1256                 gelf_getshdr(sec, &shdr);
1257
1258                 secstrs = secstrs_sym;
1259
1260                 /*
1261                  * We have to fallback to runtime when syms' section header has
1262                  * NOBITS set. NOBITS results in file offset (sh_offset) not
1263                  * being incremented. So sh_offset used below has different
1264                  * values for syms (invalid) and runtime (valid).
1265                  */
1266                 if (shdr.sh_type == SHT_NOBITS) {
1267                         sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1268                         if (!sec)
1269                                 goto out_elf_end;
1270
1271                         gelf_getshdr(sec, &shdr);
1272                         secstrs = secstrs_run;
1273                 }
1274
1275                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1276                         continue;
1277
1278                 section_name = elf_sec__name(&shdr, secstrs);
1279
1280                 /* On ARM, symbols for thumb functions have 1 added to
1281                  * the symbol address as a flag - remove it */
1282                 if ((ehdr.e_machine == EM_ARM) &&
1283                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1284                     (sym.st_value & 1))
1285                         --sym.st_value;
1286
1287                 if (dso->kernel) {
1288                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1289                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1290                                 goto out_elf_end;
1291                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1292                            (!used_opd && syms_ss->adjust_symbols)) {
1293                         GElf_Phdr phdr;
1294
1295                         if (elf_read_program_header(syms_ss->elf,
1296                                                     (u64)sym.st_value, &phdr)) {
1297                                 pr_warning("%s: failed to find program header for "
1298                                            "symbol: %s st_value: %#" PRIx64 "\n",
1299                                            __func__, elf_name, (u64)sym.st_value);
1300                                 continue;
1301                         }
1302                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1303                                   "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1304                                   __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1305                                   (u64)phdr.p_offset);
1306                         sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1307                 }
1308
1309                 demangled = demangle_sym(dso, kmodule, elf_name);
1310                 if (demangled != NULL)
1311                         elf_name = demangled;
1312
1313                 f = symbol__new(sym.st_value, sym.st_size,
1314                                 GELF_ST_BIND(sym.st_info),
1315                                 GELF_ST_TYPE(sym.st_info), elf_name);
1316                 free(demangled);
1317                 if (!f)
1318                         goto out_elf_end;
1319
1320                 arch__sym_update(f, &sym);
1321
1322                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1323                 nr++;
1324         }
1325
1326         /*
1327          * For misannotated, zeroed, ASM function sizes.
1328          */
1329         if (nr > 0) {
1330                 symbols__fixup_end(&dso->symbols, false);
1331                 symbols__fixup_duplicate(&dso->symbols);
1332                 if (kmap) {
1333                         /*
1334                          * We need to fixup this here too because we create new
1335                          * maps here, for things like vsyscall sections.
1336                          */
1337                         maps__fixup_end(kmaps);
1338                 }
1339         }
1340         err = nr;
1341 out_elf_end:
1342         return err;
1343 }
1344
1345 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1346                   struct symsrc *runtime_ss, int kmodule)
1347 {
1348         int nr = 0;
1349         int err = -1;
1350
1351         dso->symtab_type = syms_ss->type;
1352         dso->is_64_bit = syms_ss->is_64_bit;
1353         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1354
1355         /*
1356          * Modules may already have symbols from kallsyms, but those symbols
1357          * have the wrong values for the dso maps, so remove them.
1358          */
1359         if (kmodule && syms_ss->symtab)
1360                 symbols__delete(&dso->symbols);
1361
1362         if (!syms_ss->symtab) {
1363                 /*
1364                  * If the vmlinux is stripped, fail so we will fall back
1365                  * to using kallsyms. The vmlinux runtime symbols aren't
1366                  * of much use.
1367                  */
1368                 if (dso->kernel)
1369                         return err;
1370         } else  {
1371                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1372                                              kmodule, 0);
1373                 if (err < 0)
1374                         return err;
1375                 nr = err;
1376         }
1377
1378         if (syms_ss->dynsym) {
1379                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1380                                              kmodule, 1);
1381                 if (err < 0)
1382                         return err;
1383                 err += nr;
1384         }
1385
1386         return err;
1387 }
1388
1389 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1390 {
1391         GElf_Phdr phdr;
1392         size_t i, phdrnum;
1393         int err;
1394         u64 sz;
1395
1396         if (elf_getphdrnum(elf, &phdrnum))
1397                 return -1;
1398
1399         for (i = 0; i < phdrnum; i++) {
1400                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1401                         return -1;
1402                 if (phdr.p_type != PT_LOAD)
1403                         continue;
1404                 if (exe) {
1405                         if (!(phdr.p_flags & PF_X))
1406                                 continue;
1407                 } else {
1408                         if (!(phdr.p_flags & PF_R))
1409                                 continue;
1410                 }
1411                 sz = min(phdr.p_memsz, phdr.p_filesz);
1412                 if (!sz)
1413                         continue;
1414                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1415                 if (err)
1416                         return err;
1417         }
1418         return 0;
1419 }
1420
1421 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1422                     bool *is_64_bit)
1423 {
1424         int err;
1425         Elf *elf;
1426
1427         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1428         if (elf == NULL)
1429                 return -1;
1430
1431         if (is_64_bit)
1432                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1433
1434         err = elf_read_maps(elf, exe, mapfn, data);
1435
1436         elf_end(elf);
1437         return err;
1438 }
1439
1440 enum dso_type dso__type_fd(int fd)
1441 {
1442         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1443         GElf_Ehdr ehdr;
1444         Elf_Kind ek;
1445         Elf *elf;
1446
1447         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1448         if (elf == NULL)
1449                 goto out;
1450
1451         ek = elf_kind(elf);
1452         if (ek != ELF_K_ELF)
1453                 goto out_end;
1454
1455         if (gelf_getclass(elf) == ELFCLASS64) {
1456                 dso_type = DSO__TYPE_64BIT;
1457                 goto out_end;
1458         }
1459
1460         if (gelf_getehdr(elf, &ehdr) == NULL)
1461                 goto out_end;
1462
1463         if (ehdr.e_machine == EM_X86_64)
1464                 dso_type = DSO__TYPE_X32BIT;
1465         else
1466                 dso_type = DSO__TYPE_32BIT;
1467 out_end:
1468         elf_end(elf);
1469 out:
1470         return dso_type;
1471 }
1472
1473 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1474 {
1475         ssize_t r;
1476         size_t n;
1477         int err = -1;
1478         char *buf = malloc(page_size);
1479
1480         if (buf == NULL)
1481                 return -1;
1482
1483         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1484                 goto out;
1485
1486         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1487                 goto out;
1488
1489         while (len) {
1490                 n = page_size;
1491                 if (len < n)
1492                         n = len;
1493                 /* Use read because mmap won't work on proc files */
1494                 r = read(from, buf, n);
1495                 if (r < 0)
1496                         goto out;
1497                 if (!r)
1498                         break;
1499                 n = r;
1500                 r = write(to, buf, n);
1501                 if (r < 0)
1502                         goto out;
1503                 if ((size_t)r != n)
1504                         goto out;
1505                 len -= n;
1506         }
1507
1508         err = 0;
1509 out:
1510         free(buf);
1511         return err;
1512 }
1513
1514 struct kcore {
1515         int fd;
1516         int elfclass;
1517         Elf *elf;
1518         GElf_Ehdr ehdr;
1519 };
1520
1521 static int kcore__open(struct kcore *kcore, const char *filename)
1522 {
1523         GElf_Ehdr *ehdr;
1524
1525         kcore->fd = open(filename, O_RDONLY);
1526         if (kcore->fd == -1)
1527                 return -1;
1528
1529         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1530         if (!kcore->elf)
1531                 goto out_close;
1532
1533         kcore->elfclass = gelf_getclass(kcore->elf);
1534         if (kcore->elfclass == ELFCLASSNONE)
1535                 goto out_end;
1536
1537         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1538         if (!ehdr)
1539                 goto out_end;
1540
1541         return 0;
1542
1543 out_end:
1544         elf_end(kcore->elf);
1545 out_close:
1546         close(kcore->fd);
1547         return -1;
1548 }
1549
1550 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1551                        bool temp)
1552 {
1553         kcore->elfclass = elfclass;
1554
1555         if (temp)
1556                 kcore->fd = mkstemp(filename);
1557         else
1558                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1559         if (kcore->fd == -1)
1560                 return -1;
1561
1562         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1563         if (!kcore->elf)
1564                 goto out_close;
1565
1566         if (!gelf_newehdr(kcore->elf, elfclass))
1567                 goto out_end;
1568
1569         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1570
1571         return 0;
1572
1573 out_end:
1574         elf_end(kcore->elf);
1575 out_close:
1576         close(kcore->fd);
1577         unlink(filename);
1578         return -1;
1579 }
1580
1581 static void kcore__close(struct kcore *kcore)
1582 {
1583         elf_end(kcore->elf);
1584         close(kcore->fd);
1585 }
1586
1587 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1588 {
1589         GElf_Ehdr *ehdr = &to->ehdr;
1590         GElf_Ehdr *kehdr = &from->ehdr;
1591
1592         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1593         ehdr->e_type      = kehdr->e_type;
1594         ehdr->e_machine   = kehdr->e_machine;
1595         ehdr->e_version   = kehdr->e_version;
1596         ehdr->e_entry     = 0;
1597         ehdr->e_shoff     = 0;
1598         ehdr->e_flags     = kehdr->e_flags;
1599         ehdr->e_phnum     = count;
1600         ehdr->e_shentsize = 0;
1601         ehdr->e_shnum     = 0;
1602         ehdr->e_shstrndx  = 0;
1603
1604         if (from->elfclass == ELFCLASS32) {
1605                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1606                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1607                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1608         } else {
1609                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1610                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1611                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1612         }
1613
1614         if (!gelf_update_ehdr(to->elf, ehdr))
1615                 return -1;
1616
1617         if (!gelf_newphdr(to->elf, count))
1618                 return -1;
1619
1620         return 0;
1621 }
1622
1623 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1624                            u64 addr, u64 len)
1625 {
1626         GElf_Phdr phdr = {
1627                 .p_type         = PT_LOAD,
1628                 .p_flags        = PF_R | PF_W | PF_X,
1629                 .p_offset       = offset,
1630                 .p_vaddr        = addr,
1631                 .p_paddr        = 0,
1632                 .p_filesz       = len,
1633                 .p_memsz        = len,
1634                 .p_align        = page_size,
1635         };
1636
1637         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1638                 return -1;
1639
1640         return 0;
1641 }
1642
1643 static off_t kcore__write(struct kcore *kcore)
1644 {
1645         return elf_update(kcore->elf, ELF_C_WRITE);
1646 }
1647
1648 struct phdr_data {
1649         off_t offset;
1650         off_t rel;
1651         u64 addr;
1652         u64 len;
1653         struct list_head node;
1654         struct phdr_data *remaps;
1655 };
1656
1657 struct sym_data {
1658         u64 addr;
1659         struct list_head node;
1660 };
1661
1662 struct kcore_copy_info {
1663         u64 stext;
1664         u64 etext;
1665         u64 first_symbol;
1666         u64 last_symbol;
1667         u64 first_module;
1668         u64 first_module_symbol;
1669         u64 last_module_symbol;
1670         size_t phnum;
1671         struct list_head phdrs;
1672         struct list_head syms;
1673 };
1674
1675 #define kcore_copy__for_each_phdr(k, p) \
1676         list_for_each_entry((p), &(k)->phdrs, node)
1677
1678 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1679 {
1680         struct phdr_data *p = zalloc(sizeof(*p));
1681
1682         if (p) {
1683                 p->addr   = addr;
1684                 p->len    = len;
1685                 p->offset = offset;
1686         }
1687
1688         return p;
1689 }
1690
1691 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1692                                                  u64 addr, u64 len,
1693                                                  off_t offset)
1694 {
1695         struct phdr_data *p = phdr_data__new(addr, len, offset);
1696
1697         if (p)
1698                 list_add_tail(&p->node, &kci->phdrs);
1699
1700         return p;
1701 }
1702
1703 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1704 {
1705         struct phdr_data *p, *tmp;
1706
1707         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1708                 list_del_init(&p->node);
1709                 free(p);
1710         }
1711 }
1712
1713 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1714                                             u64 addr)
1715 {
1716         struct sym_data *s = zalloc(sizeof(*s));
1717
1718         if (s) {
1719                 s->addr = addr;
1720                 list_add_tail(&s->node, &kci->syms);
1721         }
1722
1723         return s;
1724 }
1725
1726 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1727 {
1728         struct sym_data *s, *tmp;
1729
1730         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1731                 list_del_init(&s->node);
1732                 free(s);
1733         }
1734 }
1735
1736 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1737                                         u64 start)
1738 {
1739         struct kcore_copy_info *kci = arg;
1740
1741         if (!kallsyms__is_function(type))
1742                 return 0;
1743
1744         if (strchr(name, '[')) {
1745                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1746                         kci->first_module_symbol = start;
1747                 if (start > kci->last_module_symbol)
1748                         kci->last_module_symbol = start;
1749                 return 0;
1750         }
1751
1752         if (!kci->first_symbol || start < kci->first_symbol)
1753                 kci->first_symbol = start;
1754
1755         if (!kci->last_symbol || start > kci->last_symbol)
1756                 kci->last_symbol = start;
1757
1758         if (!strcmp(name, "_stext")) {
1759                 kci->stext = start;
1760                 return 0;
1761         }
1762
1763         if (!strcmp(name, "_etext")) {
1764                 kci->etext = start;
1765                 return 0;
1766         }
1767
1768         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1769                 return -1;
1770
1771         return 0;
1772 }
1773
1774 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1775                                       const char *dir)
1776 {
1777         char kallsyms_filename[PATH_MAX];
1778
1779         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1780
1781         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1782                 return -1;
1783
1784         if (kallsyms__parse(kallsyms_filename, kci,
1785                             kcore_copy__process_kallsyms) < 0)
1786                 return -1;
1787
1788         return 0;
1789 }
1790
1791 static int kcore_copy__process_modules(void *arg,
1792                                        const char *name __maybe_unused,
1793                                        u64 start, u64 size __maybe_unused)
1794 {
1795         struct kcore_copy_info *kci = arg;
1796
1797         if (!kci->first_module || start < kci->first_module)
1798                 kci->first_module = start;
1799
1800         return 0;
1801 }
1802
1803 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1804                                      const char *dir)
1805 {
1806         char modules_filename[PATH_MAX];
1807
1808         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1809
1810         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1811                 return -1;
1812
1813         if (modules__parse(modules_filename, kci,
1814                            kcore_copy__process_modules) < 0)
1815                 return -1;
1816
1817         return 0;
1818 }
1819
1820 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1821                            u64 pgoff, u64 s, u64 e)
1822 {
1823         u64 len, offset;
1824
1825         if (s < start || s >= end)
1826                 return 0;
1827
1828         offset = (s - start) + pgoff;
1829         len = e < end ? e - s : end - s;
1830
1831         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1832 }
1833
1834 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1835 {
1836         struct kcore_copy_info *kci = data;
1837         u64 end = start + len;
1838         struct sym_data *sdat;
1839
1840         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1841                 return -1;
1842
1843         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1844                             kci->last_module_symbol))
1845                 return -1;
1846
1847         list_for_each_entry(sdat, &kci->syms, node) {
1848                 u64 s = round_down(sdat->addr, page_size);
1849
1850                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1851                         return -1;
1852         }
1853
1854         return 0;
1855 }
1856
1857 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1858 {
1859         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1860                 return -1;
1861
1862         return 0;
1863 }
1864
1865 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1866 {
1867         struct phdr_data *p, *k = NULL;
1868         u64 kend;
1869
1870         if (!kci->stext)
1871                 return;
1872
1873         /* Find phdr that corresponds to the kernel map (contains stext) */
1874         kcore_copy__for_each_phdr(kci, p) {
1875                 u64 pend = p->addr + p->len - 1;
1876
1877                 if (p->addr <= kci->stext && pend >= kci->stext) {
1878                         k = p;
1879                         break;
1880                 }
1881         }
1882
1883         if (!k)
1884                 return;
1885
1886         kend = k->offset + k->len;
1887
1888         /* Find phdrs that remap the kernel */
1889         kcore_copy__for_each_phdr(kci, p) {
1890                 u64 pend = p->offset + p->len;
1891
1892                 if (p == k)
1893                         continue;
1894
1895                 if (p->offset >= k->offset && pend <= kend)
1896                         p->remaps = k;
1897         }
1898 }
1899
1900 static void kcore_copy__layout(struct kcore_copy_info *kci)
1901 {
1902         struct phdr_data *p;
1903         off_t rel = 0;
1904
1905         kcore_copy__find_remaps(kci);
1906
1907         kcore_copy__for_each_phdr(kci, p) {
1908                 if (!p->remaps) {
1909                         p->rel = rel;
1910                         rel += p->len;
1911                 }
1912                 kci->phnum += 1;
1913         }
1914
1915         kcore_copy__for_each_phdr(kci, p) {
1916                 struct phdr_data *k = p->remaps;
1917
1918                 if (k)
1919                         p->rel = p->offset - k->offset + k->rel;
1920         }
1921 }
1922
1923 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1924                                  Elf *elf)
1925 {
1926         if (kcore_copy__parse_kallsyms(kci, dir))
1927                 return -1;
1928
1929         if (kcore_copy__parse_modules(kci, dir))
1930                 return -1;
1931
1932         if (kci->stext)
1933                 kci->stext = round_down(kci->stext, page_size);
1934         else
1935                 kci->stext = round_down(kci->first_symbol, page_size);
1936
1937         if (kci->etext) {
1938                 kci->etext = round_up(kci->etext, page_size);
1939         } else if (kci->last_symbol) {
1940                 kci->etext = round_up(kci->last_symbol, page_size);
1941                 kci->etext += page_size;
1942         }
1943
1944         if (kci->first_module_symbol &&
1945             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1946                 kci->first_module = kci->first_module_symbol;
1947
1948         kci->first_module = round_down(kci->first_module, page_size);
1949
1950         if (kci->last_module_symbol) {
1951                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1952                                                    page_size);
1953                 kci->last_module_symbol += page_size;
1954         }
1955
1956         if (!kci->stext || !kci->etext)
1957                 return -1;
1958
1959         if (kci->first_module && !kci->last_module_symbol)
1960                 return -1;
1961
1962         if (kcore_copy__read_maps(kci, elf))
1963                 return -1;
1964
1965         kcore_copy__layout(kci);
1966
1967         return 0;
1968 }
1969
1970 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1971                                  const char *name)
1972 {
1973         char from_filename[PATH_MAX];
1974         char to_filename[PATH_MAX];
1975
1976         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1977         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1978
1979         return copyfile_mode(from_filename, to_filename, 0400);
1980 }
1981
1982 static int kcore_copy__unlink(const char *dir, const char *name)
1983 {
1984         char filename[PATH_MAX];
1985
1986         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1987
1988         return unlink(filename);
1989 }
1990
1991 static int kcore_copy__compare_fds(int from, int to)
1992 {
1993         char *buf_from;
1994         char *buf_to;
1995         ssize_t ret;
1996         size_t len;
1997         int err = -1;
1998
1999         buf_from = malloc(page_size);
2000         buf_to = malloc(page_size);
2001         if (!buf_from || !buf_to)
2002                 goto out;
2003
2004         while (1) {
2005                 /* Use read because mmap won't work on proc files */
2006                 ret = read(from, buf_from, page_size);
2007                 if (ret < 0)
2008                         goto out;
2009
2010                 if (!ret)
2011                         break;
2012
2013                 len = ret;
2014
2015                 if (readn(to, buf_to, len) != (int)len)
2016                         goto out;
2017
2018                 if (memcmp(buf_from, buf_to, len))
2019                         goto out;
2020         }
2021
2022         err = 0;
2023 out:
2024         free(buf_to);
2025         free(buf_from);
2026         return err;
2027 }
2028
2029 static int kcore_copy__compare_files(const char *from_filename,
2030                                      const char *to_filename)
2031 {
2032         int from, to, err = -1;
2033
2034         from = open(from_filename, O_RDONLY);
2035         if (from < 0)
2036                 return -1;
2037
2038         to = open(to_filename, O_RDONLY);
2039         if (to < 0)
2040                 goto out_close_from;
2041
2042         err = kcore_copy__compare_fds(from, to);
2043
2044         close(to);
2045 out_close_from:
2046         close(from);
2047         return err;
2048 }
2049
2050 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2051                                     const char *name)
2052 {
2053         char from_filename[PATH_MAX];
2054         char to_filename[PATH_MAX];
2055
2056         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2057         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2058
2059         return kcore_copy__compare_files(from_filename, to_filename);
2060 }
2061
2062 /**
2063  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2064  * @from_dir: from directory
2065  * @to_dir: to directory
2066  *
2067  * This function copies kallsyms, modules and kcore files from one directory to
2068  * another.  kallsyms and modules are copied entirely.  Only code segments are
2069  * copied from kcore.  It is assumed that two segments suffice: one for the
2070  * kernel proper and one for all the modules.  The code segments are determined
2071  * from kallsyms and modules files.  The kernel map starts at _stext or the
2072  * lowest function symbol, and ends at _etext or the highest function symbol.
2073  * The module map starts at the lowest module address and ends at the highest
2074  * module symbol.  Start addresses are rounded down to the nearest page.  End
2075  * addresses are rounded up to the nearest page.  An extra page is added to the
2076  * highest kernel symbol and highest module symbol to, hopefully, encompass that
2077  * symbol too.  Because it contains only code sections, the resulting kcore is
2078  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
2079  * is not the same for the kernel map and the modules map.  That happens because
2080  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
2081  * kallsyms and modules files are compared with their copies to check that
2082  * modules have not been loaded or unloaded while the copies were taking place.
2083  *
2084  * Return: %0 on success, %-1 on failure.
2085  */
2086 int kcore_copy(const char *from_dir, const char *to_dir)
2087 {
2088         struct kcore kcore;
2089         struct kcore extract;
2090         int idx = 0, err = -1;
2091         off_t offset, sz;
2092         struct kcore_copy_info kci = { .stext = 0, };
2093         char kcore_filename[PATH_MAX];
2094         char extract_filename[PATH_MAX];
2095         struct phdr_data *p;
2096
2097         INIT_LIST_HEAD(&kci.phdrs);
2098         INIT_LIST_HEAD(&kci.syms);
2099
2100         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2101                 return -1;
2102
2103         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2104                 goto out_unlink_kallsyms;
2105
2106         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2107         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2108
2109         if (kcore__open(&kcore, kcore_filename))
2110                 goto out_unlink_modules;
2111
2112         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2113                 goto out_kcore_close;
2114
2115         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2116                 goto out_kcore_close;
2117
2118         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2119                 goto out_extract_close;
2120
2121         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2122                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2123         offset = round_up(offset, page_size);
2124
2125         kcore_copy__for_each_phdr(&kci, p) {
2126                 off_t offs = p->rel + offset;
2127
2128                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2129                         goto out_extract_close;
2130         }
2131
2132         sz = kcore__write(&extract);
2133         if (sz < 0 || sz > offset)
2134                 goto out_extract_close;
2135
2136         kcore_copy__for_each_phdr(&kci, p) {
2137                 off_t offs = p->rel + offset;
2138
2139                 if (p->remaps)
2140                         continue;
2141                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2142                         goto out_extract_close;
2143         }
2144
2145         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
2146                 goto out_extract_close;
2147
2148         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2149                 goto out_extract_close;
2150
2151         err = 0;
2152
2153 out_extract_close:
2154         kcore__close(&extract);
2155         if (err)
2156                 unlink(extract_filename);
2157 out_kcore_close:
2158         kcore__close(&kcore);
2159 out_unlink_modules:
2160         if (err)
2161                 kcore_copy__unlink(to_dir, "modules");
2162 out_unlink_kallsyms:
2163         if (err)
2164                 kcore_copy__unlink(to_dir, "kallsyms");
2165
2166         kcore_copy__free_phdrs(&kci);
2167         kcore_copy__free_syms(&kci);
2168
2169         return err;
2170 }
2171
2172 int kcore_extract__create(struct kcore_extract *kce)
2173 {
2174         struct kcore kcore;
2175         struct kcore extract;
2176         size_t count = 1;
2177         int idx = 0, err = -1;
2178         off_t offset = page_size, sz;
2179
2180         if (kcore__open(&kcore, kce->kcore_filename))
2181                 return -1;
2182
2183         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2184         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2185                 goto out_kcore_close;
2186
2187         if (kcore__copy_hdr(&kcore, &extract, count))
2188                 goto out_extract_close;
2189
2190         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2191                 goto out_extract_close;
2192
2193         sz = kcore__write(&extract);
2194         if (sz < 0 || sz > offset)
2195                 goto out_extract_close;
2196
2197         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2198                 goto out_extract_close;
2199
2200         err = 0;
2201
2202 out_extract_close:
2203         kcore__close(&extract);
2204         if (err)
2205                 unlink(kce->extract_filename);
2206 out_kcore_close:
2207         kcore__close(&kcore);
2208
2209         return err;
2210 }
2211
2212 void kcore_extract__delete(struct kcore_extract *kce)
2213 {
2214         unlink(kce->extract_filename);
2215 }
2216
2217 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2218
2219 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2220 {
2221         if (!base_off)
2222                 return;
2223
2224         if (tmp->bit32)
2225                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2226                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2227                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2228         else
2229                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2230                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2231                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2232 }
2233
2234 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2235                               GElf_Addr base_off)
2236 {
2237         if (!base_off)
2238                 return;
2239
2240         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2241                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2242         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2243                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2244 }
2245
2246 /**
2247  * populate_sdt_note : Parse raw data and identify SDT note
2248  * @elf: elf of the opened file
2249  * @data: raw data of a section with description offset applied
2250  * @len: note description size
2251  * @type: type of the note
2252  * @sdt_notes: List to add the SDT note
2253  *
2254  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2255  * if its an SDT note, it appends to @sdt_notes list.
2256  */
2257 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2258                              struct list_head *sdt_notes)
2259 {
2260         const char *provider, *name, *args;
2261         struct sdt_note *tmp = NULL;
2262         GElf_Ehdr ehdr;
2263         GElf_Shdr shdr;
2264         int ret = -EINVAL;
2265
2266         union {
2267                 Elf64_Addr a64[NR_ADDR];
2268                 Elf32_Addr a32[NR_ADDR];
2269         } buf;
2270
2271         Elf_Data dst = {
2272                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2273                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2274                 .d_off = 0, .d_align = 0
2275         };
2276         Elf_Data src = {
2277                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2278                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2279                 .d_align = 0
2280         };
2281
2282         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2283         if (!tmp) {
2284                 ret = -ENOMEM;
2285                 goto out_err;
2286         }
2287
2288         INIT_LIST_HEAD(&tmp->note_list);
2289
2290         if (len < dst.d_size + 3)
2291                 goto out_free_note;
2292
2293         /* Translation from file representation to memory representation */
2294         if (gelf_xlatetom(*elf, &dst, &src,
2295                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2296                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2297                 goto out_free_note;
2298         }
2299
2300         /* Populate the fields of sdt_note */
2301         provider = data + dst.d_size;
2302
2303         name = (const char *)memchr(provider, '\0', data + len - provider);
2304         if (name++ == NULL)
2305                 goto out_free_note;
2306
2307         tmp->provider = strdup(provider);
2308         if (!tmp->provider) {
2309                 ret = -ENOMEM;
2310                 goto out_free_note;
2311         }
2312         tmp->name = strdup(name);
2313         if (!tmp->name) {
2314                 ret = -ENOMEM;
2315                 goto out_free_prov;
2316         }
2317
2318         args = memchr(name, '\0', data + len - name);
2319
2320         /*
2321          * There is no argument if:
2322          * - We reached the end of the note;
2323          * - There is not enough room to hold a potential string;
2324          * - The argument string is empty or just contains ':'.
2325          */
2326         if (args == NULL || data + len - args < 2 ||
2327                 args[1] == ':' || args[1] == '\0')
2328                 tmp->args = NULL;
2329         else {
2330                 tmp->args = strdup(++args);
2331                 if (!tmp->args) {
2332                         ret = -ENOMEM;
2333                         goto out_free_name;
2334                 }
2335         }
2336
2337         if (gelf_getclass(*elf) == ELFCLASS32) {
2338                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2339                 tmp->bit32 = true;
2340         } else {
2341                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2342                 tmp->bit32 = false;
2343         }
2344
2345         if (!gelf_getehdr(*elf, &ehdr)) {
2346                 pr_debug("%s : cannot get elf header.\n", __func__);
2347                 ret = -EBADF;
2348                 goto out_free_args;
2349         }
2350
2351         /* Adjust the prelink effect :
2352          * Find out the .stapsdt.base section.
2353          * This scn will help us to handle prelinking (if present).
2354          * Compare the retrieved file offset of the base section with the
2355          * base address in the description of the SDT note. If its different,
2356          * then accordingly, adjust the note location.
2357          */
2358         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2359                 sdt_adjust_loc(tmp, shdr.sh_offset);
2360
2361         /* Adjust reference counter offset */
2362         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2363                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2364
2365         list_add_tail(&tmp->note_list, sdt_notes);
2366         return 0;
2367
2368 out_free_args:
2369         zfree(&tmp->args);
2370 out_free_name:
2371         zfree(&tmp->name);
2372 out_free_prov:
2373         zfree(&tmp->provider);
2374 out_free_note:
2375         free(tmp);
2376 out_err:
2377         return ret;
2378 }
2379
2380 /**
2381  * construct_sdt_notes_list : constructs a list of SDT notes
2382  * @elf : elf to look into
2383  * @sdt_notes : empty list_head
2384  *
2385  * Scans the sections in 'elf' for the section
2386  * .note.stapsdt. It, then calls populate_sdt_note to find
2387  * out the SDT events and populates the 'sdt_notes'.
2388  */
2389 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2390 {
2391         GElf_Ehdr ehdr;
2392         Elf_Scn *scn = NULL;
2393         Elf_Data *data;
2394         GElf_Shdr shdr;
2395         size_t shstrndx, next;
2396         GElf_Nhdr nhdr;
2397         size_t name_off, desc_off, offset;
2398         int ret = 0;
2399
2400         if (gelf_getehdr(elf, &ehdr) == NULL) {
2401                 ret = -EBADF;
2402                 goto out_ret;
2403         }
2404         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2405                 ret = -EBADF;
2406                 goto out_ret;
2407         }
2408
2409         /* Look for the required section */
2410         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2411         if (!scn) {
2412                 ret = -ENOENT;
2413                 goto out_ret;
2414         }
2415
2416         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2417                 ret = -ENOENT;
2418                 goto out_ret;
2419         }
2420
2421         data = elf_getdata(scn, NULL);
2422
2423         /* Get the SDT notes */
2424         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2425                                               &desc_off)) > 0; offset = next) {
2426                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2427                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2428                             sizeof(SDT_NOTE_NAME))) {
2429                         /* Check the type of the note */
2430                         if (nhdr.n_type != SDT_NOTE_TYPE)
2431                                 goto out_ret;
2432
2433                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2434                                                 nhdr.n_descsz, sdt_notes);
2435                         if (ret < 0)
2436                                 goto out_ret;
2437                 }
2438         }
2439         if (list_empty(sdt_notes))
2440                 ret = -ENOENT;
2441
2442 out_ret:
2443         return ret;
2444 }
2445
2446 /**
2447  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2448  * @head : empty list_head
2449  * @target : file to find SDT notes from
2450  *
2451  * This opens the file, initializes
2452  * the ELF and then calls construct_sdt_notes_list.
2453  */
2454 int get_sdt_note_list(struct list_head *head, const char *target)
2455 {
2456         Elf *elf;
2457         int fd, ret;
2458
2459         fd = open(target, O_RDONLY);
2460         if (fd < 0)
2461                 return -EBADF;
2462
2463         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2464         if (!elf) {
2465                 ret = -EBADF;
2466                 goto out_close;
2467         }
2468         ret = construct_sdt_notes_list(elf, head);
2469         elf_end(elf);
2470 out_close:
2471         close(fd);
2472         return ret;
2473 }
2474
2475 /**
2476  * cleanup_sdt_note_list : free the sdt notes' list
2477  * @sdt_notes: sdt notes' list
2478  *
2479  * Free up the SDT notes in @sdt_notes.
2480  * Returns the number of SDT notes free'd.
2481  */
2482 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2483 {
2484         struct sdt_note *tmp, *pos;
2485         int nr_free = 0;
2486
2487         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2488                 list_del_init(&pos->note_list);
2489                 zfree(&pos->args);
2490                 zfree(&pos->name);
2491                 zfree(&pos->provider);
2492                 free(pos);
2493                 nr_free++;
2494         }
2495         return nr_free;
2496 }
2497
2498 /**
2499  * sdt_notes__get_count: Counts the number of sdt events
2500  * @start: list_head to sdt_notes list
2501  *
2502  * Returns the number of SDT notes in a list
2503  */
2504 int sdt_notes__get_count(struct list_head *start)
2505 {
2506         struct sdt_note *sdt_ptr;
2507         int count = 0;
2508
2509         list_for_each_entry(sdt_ptr, start, note_list)
2510                 count++;
2511         return count;
2512 }
2513 #endif
2514
2515 void symbol__elf_init(void)
2516 {
2517         elf_version(EV_CURRENT);
2518 }