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                 /*
1259                  * If the attribute bit SHF_ALLOC is not set, the section
1260                  * doesn't occupy memory during process execution.
1261                  * E.g. ".gnu.warning.*" section is used by linker to generate
1262                  * warnings when calling deprecated functions, the symbols in
1263                  * the section aren't loaded to memory during process execution,
1264                  * so skip them.
1265                  */
1266                 if (!(shdr.sh_flags & SHF_ALLOC))
1267                         continue;
1268
1269                 secstrs = secstrs_sym;
1270
1271                 /*
1272                  * We have to fallback to runtime when syms' section header has
1273                  * NOBITS set. NOBITS results in file offset (sh_offset) not
1274                  * being incremented. So sh_offset used below has different
1275                  * values for syms (invalid) and runtime (valid).
1276                  */
1277                 if (shdr.sh_type == SHT_NOBITS) {
1278                         sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1279                         if (!sec)
1280                                 goto out_elf_end;
1281
1282                         gelf_getshdr(sec, &shdr);
1283                         secstrs = secstrs_run;
1284                 }
1285
1286                 if (is_label && !elf_sec__filter(&shdr, secstrs))
1287                         continue;
1288
1289                 section_name = elf_sec__name(&shdr, secstrs);
1290
1291                 /* On ARM, symbols for thumb functions have 1 added to
1292                  * the symbol address as a flag - remove it */
1293                 if ((ehdr.e_machine == EM_ARM) &&
1294                     (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1295                     (sym.st_value & 1))
1296                         --sym.st_value;
1297
1298                 if (dso->kernel) {
1299                         if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1300                                                        section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1301                                 goto out_elf_end;
1302                 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1303                            (!used_opd && syms_ss->adjust_symbols)) {
1304                         GElf_Phdr phdr;
1305
1306                         if (elf_read_program_header(syms_ss->elf,
1307                                                     (u64)sym.st_value, &phdr)) {
1308                                 pr_warning("%s: failed to find program header for "
1309                                            "symbol: %s st_value: %#" PRIx64 "\n",
1310                                            __func__, elf_name, (u64)sym.st_value);
1311                                 continue;
1312                         }
1313                         pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1314                                   "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",
1315                                   __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,
1316                                   (u64)phdr.p_offset);
1317                         sym.st_value -= phdr.p_vaddr - phdr.p_offset;
1318                 }
1319
1320                 demangled = demangle_sym(dso, kmodule, elf_name);
1321                 if (demangled != NULL)
1322                         elf_name = demangled;
1323
1324                 f = symbol__new(sym.st_value, sym.st_size,
1325                                 GELF_ST_BIND(sym.st_info),
1326                                 GELF_ST_TYPE(sym.st_info), elf_name);
1327                 free(demangled);
1328                 if (!f)
1329                         goto out_elf_end;
1330
1331                 arch__sym_update(f, &sym);
1332
1333                 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1334                 nr++;
1335         }
1336
1337         /*
1338          * For misannotated, zeroed, ASM function sizes.
1339          */
1340         if (nr > 0) {
1341                 symbols__fixup_end(&dso->symbols, false);
1342                 symbols__fixup_duplicate(&dso->symbols);
1343                 if (kmap) {
1344                         /*
1345                          * We need to fixup this here too because we create new
1346                          * maps here, for things like vsyscall sections.
1347                          */
1348                         maps__fixup_end(kmaps);
1349                 }
1350         }
1351         err = nr;
1352 out_elf_end:
1353         return err;
1354 }
1355
1356 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
1357                   struct symsrc *runtime_ss, int kmodule)
1358 {
1359         int nr = 0;
1360         int err = -1;
1361
1362         dso->symtab_type = syms_ss->type;
1363         dso->is_64_bit = syms_ss->is_64_bit;
1364         dso->rel = syms_ss->ehdr.e_type == ET_REL;
1365
1366         /*
1367          * Modules may already have symbols from kallsyms, but those symbols
1368          * have the wrong values for the dso maps, so remove them.
1369          */
1370         if (kmodule && syms_ss->symtab)
1371                 symbols__delete(&dso->symbols);
1372
1373         if (!syms_ss->symtab) {
1374                 /*
1375                  * If the vmlinux is stripped, fail so we will fall back
1376                  * to using kallsyms. The vmlinux runtime symbols aren't
1377                  * of much use.
1378                  */
1379                 if (dso->kernel)
1380                         return err;
1381         } else  {
1382                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1383                                              kmodule, 0);
1384                 if (err < 0)
1385                         return err;
1386                 nr = err;
1387         }
1388
1389         if (syms_ss->dynsym) {
1390                 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,
1391                                              kmodule, 1);
1392                 if (err < 0)
1393                         return err;
1394                 err += nr;
1395         }
1396
1397         return err;
1398 }
1399
1400 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1401 {
1402         GElf_Phdr phdr;
1403         size_t i, phdrnum;
1404         int err;
1405         u64 sz;
1406
1407         if (elf_getphdrnum(elf, &phdrnum))
1408                 return -1;
1409
1410         for (i = 0; i < phdrnum; i++) {
1411                 if (gelf_getphdr(elf, i, &phdr) == NULL)
1412                         return -1;
1413                 if (phdr.p_type != PT_LOAD)
1414                         continue;
1415                 if (exe) {
1416                         if (!(phdr.p_flags & PF_X))
1417                                 continue;
1418                 } else {
1419                         if (!(phdr.p_flags & PF_R))
1420                                 continue;
1421                 }
1422                 sz = min(phdr.p_memsz, phdr.p_filesz);
1423                 if (!sz)
1424                         continue;
1425                 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1426                 if (err)
1427                         return err;
1428         }
1429         return 0;
1430 }
1431
1432 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1433                     bool *is_64_bit)
1434 {
1435         int err;
1436         Elf *elf;
1437
1438         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1439         if (elf == NULL)
1440                 return -1;
1441
1442         if (is_64_bit)
1443                 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1444
1445         err = elf_read_maps(elf, exe, mapfn, data);
1446
1447         elf_end(elf);
1448         return err;
1449 }
1450
1451 enum dso_type dso__type_fd(int fd)
1452 {
1453         enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1454         GElf_Ehdr ehdr;
1455         Elf_Kind ek;
1456         Elf *elf;
1457
1458         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1459         if (elf == NULL)
1460                 goto out;
1461
1462         ek = elf_kind(elf);
1463         if (ek != ELF_K_ELF)
1464                 goto out_end;
1465
1466         if (gelf_getclass(elf) == ELFCLASS64) {
1467                 dso_type = DSO__TYPE_64BIT;
1468                 goto out_end;
1469         }
1470
1471         if (gelf_getehdr(elf, &ehdr) == NULL)
1472                 goto out_end;
1473
1474         if (ehdr.e_machine == EM_X86_64)
1475                 dso_type = DSO__TYPE_X32BIT;
1476         else
1477                 dso_type = DSO__TYPE_32BIT;
1478 out_end:
1479         elf_end(elf);
1480 out:
1481         return dso_type;
1482 }
1483
1484 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1485 {
1486         ssize_t r;
1487         size_t n;
1488         int err = -1;
1489         char *buf = malloc(page_size);
1490
1491         if (buf == NULL)
1492                 return -1;
1493
1494         if (lseek(to, to_offs, SEEK_SET) != to_offs)
1495                 goto out;
1496
1497         if (lseek(from, from_offs, SEEK_SET) != from_offs)
1498                 goto out;
1499
1500         while (len) {
1501                 n = page_size;
1502                 if (len < n)
1503                         n = len;
1504                 /* Use read because mmap won't work on proc files */
1505                 r = read(from, buf, n);
1506                 if (r < 0)
1507                         goto out;
1508                 if (!r)
1509                         break;
1510                 n = r;
1511                 r = write(to, buf, n);
1512                 if (r < 0)
1513                         goto out;
1514                 if ((size_t)r != n)
1515                         goto out;
1516                 len -= n;
1517         }
1518
1519         err = 0;
1520 out:
1521         free(buf);
1522         return err;
1523 }
1524
1525 struct kcore {
1526         int fd;
1527         int elfclass;
1528         Elf *elf;
1529         GElf_Ehdr ehdr;
1530 };
1531
1532 static int kcore__open(struct kcore *kcore, const char *filename)
1533 {
1534         GElf_Ehdr *ehdr;
1535
1536         kcore->fd = open(filename, O_RDONLY);
1537         if (kcore->fd == -1)
1538                 return -1;
1539
1540         kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1541         if (!kcore->elf)
1542                 goto out_close;
1543
1544         kcore->elfclass = gelf_getclass(kcore->elf);
1545         if (kcore->elfclass == ELFCLASSNONE)
1546                 goto out_end;
1547
1548         ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1549         if (!ehdr)
1550                 goto out_end;
1551
1552         return 0;
1553
1554 out_end:
1555         elf_end(kcore->elf);
1556 out_close:
1557         close(kcore->fd);
1558         return -1;
1559 }
1560
1561 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1562                        bool temp)
1563 {
1564         kcore->elfclass = elfclass;
1565
1566         if (temp)
1567                 kcore->fd = mkstemp(filename);
1568         else
1569                 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1570         if (kcore->fd == -1)
1571                 return -1;
1572
1573         kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1574         if (!kcore->elf)
1575                 goto out_close;
1576
1577         if (!gelf_newehdr(kcore->elf, elfclass))
1578                 goto out_end;
1579
1580         memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1581
1582         return 0;
1583
1584 out_end:
1585         elf_end(kcore->elf);
1586 out_close:
1587         close(kcore->fd);
1588         unlink(filename);
1589         return -1;
1590 }
1591
1592 static void kcore__close(struct kcore *kcore)
1593 {
1594         elf_end(kcore->elf);
1595         close(kcore->fd);
1596 }
1597
1598 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1599 {
1600         GElf_Ehdr *ehdr = &to->ehdr;
1601         GElf_Ehdr *kehdr = &from->ehdr;
1602
1603         memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1604         ehdr->e_type      = kehdr->e_type;
1605         ehdr->e_machine   = kehdr->e_machine;
1606         ehdr->e_version   = kehdr->e_version;
1607         ehdr->e_entry     = 0;
1608         ehdr->e_shoff     = 0;
1609         ehdr->e_flags     = kehdr->e_flags;
1610         ehdr->e_phnum     = count;
1611         ehdr->e_shentsize = 0;
1612         ehdr->e_shnum     = 0;
1613         ehdr->e_shstrndx  = 0;
1614
1615         if (from->elfclass == ELFCLASS32) {
1616                 ehdr->e_phoff     = sizeof(Elf32_Ehdr);
1617                 ehdr->e_ehsize    = sizeof(Elf32_Ehdr);
1618                 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1619         } else {
1620                 ehdr->e_phoff     = sizeof(Elf64_Ehdr);
1621                 ehdr->e_ehsize    = sizeof(Elf64_Ehdr);
1622                 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1623         }
1624
1625         if (!gelf_update_ehdr(to->elf, ehdr))
1626                 return -1;
1627
1628         if (!gelf_newphdr(to->elf, count))
1629                 return -1;
1630
1631         return 0;
1632 }
1633
1634 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1635                            u64 addr, u64 len)
1636 {
1637         GElf_Phdr phdr = {
1638                 .p_type         = PT_LOAD,
1639                 .p_flags        = PF_R | PF_W | PF_X,
1640                 .p_offset       = offset,
1641                 .p_vaddr        = addr,
1642                 .p_paddr        = 0,
1643                 .p_filesz       = len,
1644                 .p_memsz        = len,
1645                 .p_align        = page_size,
1646         };
1647
1648         if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1649                 return -1;
1650
1651         return 0;
1652 }
1653
1654 static off_t kcore__write(struct kcore *kcore)
1655 {
1656         return elf_update(kcore->elf, ELF_C_WRITE);
1657 }
1658
1659 struct phdr_data {
1660         off_t offset;
1661         off_t rel;
1662         u64 addr;
1663         u64 len;
1664         struct list_head node;
1665         struct phdr_data *remaps;
1666 };
1667
1668 struct sym_data {
1669         u64 addr;
1670         struct list_head node;
1671 };
1672
1673 struct kcore_copy_info {
1674         u64 stext;
1675         u64 etext;
1676         u64 first_symbol;
1677         u64 last_symbol;
1678         u64 first_module;
1679         u64 first_module_symbol;
1680         u64 last_module_symbol;
1681         size_t phnum;
1682         struct list_head phdrs;
1683         struct list_head syms;
1684 };
1685
1686 #define kcore_copy__for_each_phdr(k, p) \
1687         list_for_each_entry((p), &(k)->phdrs, node)
1688
1689 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1690 {
1691         struct phdr_data *p = zalloc(sizeof(*p));
1692
1693         if (p) {
1694                 p->addr   = addr;
1695                 p->len    = len;
1696                 p->offset = offset;
1697         }
1698
1699         return p;
1700 }
1701
1702 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1703                                                  u64 addr, u64 len,
1704                                                  off_t offset)
1705 {
1706         struct phdr_data *p = phdr_data__new(addr, len, offset);
1707
1708         if (p)
1709                 list_add_tail(&p->node, &kci->phdrs);
1710
1711         return p;
1712 }
1713
1714 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1715 {
1716         struct phdr_data *p, *tmp;
1717
1718         list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1719                 list_del_init(&p->node);
1720                 free(p);
1721         }
1722 }
1723
1724 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1725                                             u64 addr)
1726 {
1727         struct sym_data *s = zalloc(sizeof(*s));
1728
1729         if (s) {
1730                 s->addr = addr;
1731                 list_add_tail(&s->node, &kci->syms);
1732         }
1733
1734         return s;
1735 }
1736
1737 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1738 {
1739         struct sym_data *s, *tmp;
1740
1741         list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1742                 list_del_init(&s->node);
1743                 free(s);
1744         }
1745 }
1746
1747 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1748                                         u64 start)
1749 {
1750         struct kcore_copy_info *kci = arg;
1751
1752         if (!kallsyms__is_function(type))
1753                 return 0;
1754
1755         if (strchr(name, '[')) {
1756                 if (!kci->first_module_symbol || start < kci->first_module_symbol)
1757                         kci->first_module_symbol = start;
1758                 if (start > kci->last_module_symbol)
1759                         kci->last_module_symbol = start;
1760                 return 0;
1761         }
1762
1763         if (!kci->first_symbol || start < kci->first_symbol)
1764                 kci->first_symbol = start;
1765
1766         if (!kci->last_symbol || start > kci->last_symbol)
1767                 kci->last_symbol = start;
1768
1769         if (!strcmp(name, "_stext")) {
1770                 kci->stext = start;
1771                 return 0;
1772         }
1773
1774         if (!strcmp(name, "_etext")) {
1775                 kci->etext = start;
1776                 return 0;
1777         }
1778
1779         if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1780                 return -1;
1781
1782         return 0;
1783 }
1784
1785 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1786                                       const char *dir)
1787 {
1788         char kallsyms_filename[PATH_MAX];
1789
1790         scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1791
1792         if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1793                 return -1;
1794
1795         if (kallsyms__parse(kallsyms_filename, kci,
1796                             kcore_copy__process_kallsyms) < 0)
1797                 return -1;
1798
1799         return 0;
1800 }
1801
1802 static int kcore_copy__process_modules(void *arg,
1803                                        const char *name __maybe_unused,
1804                                        u64 start, u64 size __maybe_unused)
1805 {
1806         struct kcore_copy_info *kci = arg;
1807
1808         if (!kci->first_module || start < kci->first_module)
1809                 kci->first_module = start;
1810
1811         return 0;
1812 }
1813
1814 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1815                                      const char *dir)
1816 {
1817         char modules_filename[PATH_MAX];
1818
1819         scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1820
1821         if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1822                 return -1;
1823
1824         if (modules__parse(modules_filename, kci,
1825                            kcore_copy__process_modules) < 0)
1826                 return -1;
1827
1828         return 0;
1829 }
1830
1831 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1832                            u64 pgoff, u64 s, u64 e)
1833 {
1834         u64 len, offset;
1835
1836         if (s < start || s >= end)
1837                 return 0;
1838
1839         offset = (s - start) + pgoff;
1840         len = e < end ? e - s : end - s;
1841
1842         return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1843 }
1844
1845 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1846 {
1847         struct kcore_copy_info *kci = data;
1848         u64 end = start + len;
1849         struct sym_data *sdat;
1850
1851         if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1852                 return -1;
1853
1854         if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1855                             kci->last_module_symbol))
1856                 return -1;
1857
1858         list_for_each_entry(sdat, &kci->syms, node) {
1859                 u64 s = round_down(sdat->addr, page_size);
1860
1861                 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1862                         return -1;
1863         }
1864
1865         return 0;
1866 }
1867
1868 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1869 {
1870         if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1871                 return -1;
1872
1873         return 0;
1874 }
1875
1876 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1877 {
1878         struct phdr_data *p, *k = NULL;
1879         u64 kend;
1880
1881         if (!kci->stext)
1882                 return;
1883
1884         /* Find phdr that corresponds to the kernel map (contains stext) */
1885         kcore_copy__for_each_phdr(kci, p) {
1886                 u64 pend = p->addr + p->len - 1;
1887
1888                 if (p->addr <= kci->stext && pend >= kci->stext) {
1889                         k = p;
1890                         break;
1891                 }
1892         }
1893
1894         if (!k)
1895                 return;
1896
1897         kend = k->offset + k->len;
1898
1899         /* Find phdrs that remap the kernel */
1900         kcore_copy__for_each_phdr(kci, p) {
1901                 u64 pend = p->offset + p->len;
1902
1903                 if (p == k)
1904                         continue;
1905
1906                 if (p->offset >= k->offset && pend <= kend)
1907                         p->remaps = k;
1908         }
1909 }
1910
1911 static void kcore_copy__layout(struct kcore_copy_info *kci)
1912 {
1913         struct phdr_data *p;
1914         off_t rel = 0;
1915
1916         kcore_copy__find_remaps(kci);
1917
1918         kcore_copy__for_each_phdr(kci, p) {
1919                 if (!p->remaps) {
1920                         p->rel = rel;
1921                         rel += p->len;
1922                 }
1923                 kci->phnum += 1;
1924         }
1925
1926         kcore_copy__for_each_phdr(kci, p) {
1927                 struct phdr_data *k = p->remaps;
1928
1929                 if (k)
1930                         p->rel = p->offset - k->offset + k->rel;
1931         }
1932 }
1933
1934 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1935                                  Elf *elf)
1936 {
1937         if (kcore_copy__parse_kallsyms(kci, dir))
1938                 return -1;
1939
1940         if (kcore_copy__parse_modules(kci, dir))
1941                 return -1;
1942
1943         if (kci->stext)
1944                 kci->stext = round_down(kci->stext, page_size);
1945         else
1946                 kci->stext = round_down(kci->first_symbol, page_size);
1947
1948         if (kci->etext) {
1949                 kci->etext = round_up(kci->etext, page_size);
1950         } else if (kci->last_symbol) {
1951                 kci->etext = round_up(kci->last_symbol, page_size);
1952                 kci->etext += page_size;
1953         }
1954
1955         if (kci->first_module_symbol &&
1956             (!kci->first_module || kci->first_module_symbol < kci->first_module))
1957                 kci->first_module = kci->first_module_symbol;
1958
1959         kci->first_module = round_down(kci->first_module, page_size);
1960
1961         if (kci->last_module_symbol) {
1962                 kci->last_module_symbol = round_up(kci->last_module_symbol,
1963                                                    page_size);
1964                 kci->last_module_symbol += page_size;
1965         }
1966
1967         if (!kci->stext || !kci->etext)
1968                 return -1;
1969
1970         if (kci->first_module && !kci->last_module_symbol)
1971                 return -1;
1972
1973         if (kcore_copy__read_maps(kci, elf))
1974                 return -1;
1975
1976         kcore_copy__layout(kci);
1977
1978         return 0;
1979 }
1980
1981 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1982                                  const char *name)
1983 {
1984         char from_filename[PATH_MAX];
1985         char to_filename[PATH_MAX];
1986
1987         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1988         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1989
1990         return copyfile_mode(from_filename, to_filename, 0400);
1991 }
1992
1993 static int kcore_copy__unlink(const char *dir, const char *name)
1994 {
1995         char filename[PATH_MAX];
1996
1997         scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1998
1999         return unlink(filename);
2000 }
2001
2002 static int kcore_copy__compare_fds(int from, int to)
2003 {
2004         char *buf_from;
2005         char *buf_to;
2006         ssize_t ret;
2007         size_t len;
2008         int err = -1;
2009
2010         buf_from = malloc(page_size);
2011         buf_to = malloc(page_size);
2012         if (!buf_from || !buf_to)
2013                 goto out;
2014
2015         while (1) {
2016                 /* Use read because mmap won't work on proc files */
2017                 ret = read(from, buf_from, page_size);
2018                 if (ret < 0)
2019                         goto out;
2020
2021                 if (!ret)
2022                         break;
2023
2024                 len = ret;
2025
2026                 if (readn(to, buf_to, len) != (int)len)
2027                         goto out;
2028
2029                 if (memcmp(buf_from, buf_to, len))
2030                         goto out;
2031         }
2032
2033         err = 0;
2034 out:
2035         free(buf_to);
2036         free(buf_from);
2037         return err;
2038 }
2039
2040 static int kcore_copy__compare_files(const char *from_filename,
2041                                      const char *to_filename)
2042 {
2043         int from, to, err = -1;
2044
2045         from = open(from_filename, O_RDONLY);
2046         if (from < 0)
2047                 return -1;
2048
2049         to = open(to_filename, O_RDONLY);
2050         if (to < 0)
2051                 goto out_close_from;
2052
2053         err = kcore_copy__compare_fds(from, to);
2054
2055         close(to);
2056 out_close_from:
2057         close(from);
2058         return err;
2059 }
2060
2061 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
2062                                     const char *name)
2063 {
2064         char from_filename[PATH_MAX];
2065         char to_filename[PATH_MAX];
2066
2067         scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
2068         scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
2069
2070         return kcore_copy__compare_files(from_filename, to_filename);
2071 }
2072
2073 /**
2074  * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
2075  * @from_dir: from directory
2076  * @to_dir: to directory
2077  *
2078  * This function copies kallsyms, modules and kcore files from one directory to
2079  * another.  kallsyms and modules are copied entirely.  Only code segments are
2080  * copied from kcore.  It is assumed that two segments suffice: one for the
2081  * kernel proper and one for all the modules.  The code segments are determined
2082  * from kallsyms and modules files.  The kernel map starts at _stext or the
2083  * lowest function symbol, and ends at _etext or the highest function symbol.
2084  * The module map starts at the lowest module address and ends at the highest
2085  * module symbol.  Start addresses are rounded down to the nearest page.  End
2086  * addresses are rounded up to the nearest page.  An extra page is added to the
2087  * highest kernel symbol and highest module symbol to, hopefully, encompass that
2088  * symbol too.  Because it contains only code sections, the resulting kcore is
2089  * unusual.  One significant peculiarity is that the mapping (start -> pgoff)
2090  * is not the same for the kernel map and the modules map.  That happens because
2091  * the data is copied adjacently whereas the original kcore has gaps.  Finally,
2092  * kallsyms and modules files are compared with their copies to check that
2093  * modules have not been loaded or unloaded while the copies were taking place.
2094  *
2095  * Return: %0 on success, %-1 on failure.
2096  */
2097 int kcore_copy(const char *from_dir, const char *to_dir)
2098 {
2099         struct kcore kcore;
2100         struct kcore extract;
2101         int idx = 0, err = -1;
2102         off_t offset, sz;
2103         struct kcore_copy_info kci = { .stext = 0, };
2104         char kcore_filename[PATH_MAX];
2105         char extract_filename[PATH_MAX];
2106         struct phdr_data *p;
2107
2108         INIT_LIST_HEAD(&kci.phdrs);
2109         INIT_LIST_HEAD(&kci.syms);
2110
2111         if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
2112                 return -1;
2113
2114         if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
2115                 goto out_unlink_kallsyms;
2116
2117         scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
2118         scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
2119
2120         if (kcore__open(&kcore, kcore_filename))
2121                 goto out_unlink_modules;
2122
2123         if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
2124                 goto out_kcore_close;
2125
2126         if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
2127                 goto out_kcore_close;
2128
2129         if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
2130                 goto out_extract_close;
2131
2132         offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
2133                  gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
2134         offset = round_up(offset, page_size);
2135
2136         kcore_copy__for_each_phdr(&kci, p) {
2137                 off_t offs = p->rel + offset;
2138
2139                 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
2140                         goto out_extract_close;
2141         }
2142
2143         sz = kcore__write(&extract);
2144         if (sz < 0 || sz > offset)
2145                 goto out_extract_close;
2146
2147         kcore_copy__for_each_phdr(&kci, p) {
2148                 off_t offs = p->rel + offset;
2149
2150                 if (p->remaps)
2151                         continue;
2152                 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
2153                         goto out_extract_close;
2154         }
2155
2156         if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
2157                 goto out_extract_close;
2158
2159         if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
2160                 goto out_extract_close;
2161
2162         err = 0;
2163
2164 out_extract_close:
2165         kcore__close(&extract);
2166         if (err)
2167                 unlink(extract_filename);
2168 out_kcore_close:
2169         kcore__close(&kcore);
2170 out_unlink_modules:
2171         if (err)
2172                 kcore_copy__unlink(to_dir, "modules");
2173 out_unlink_kallsyms:
2174         if (err)
2175                 kcore_copy__unlink(to_dir, "kallsyms");
2176
2177         kcore_copy__free_phdrs(&kci);
2178         kcore_copy__free_syms(&kci);
2179
2180         return err;
2181 }
2182
2183 int kcore_extract__create(struct kcore_extract *kce)
2184 {
2185         struct kcore kcore;
2186         struct kcore extract;
2187         size_t count = 1;
2188         int idx = 0, err = -1;
2189         off_t offset = page_size, sz;
2190
2191         if (kcore__open(&kcore, kce->kcore_filename))
2192                 return -1;
2193
2194         strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
2195         if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
2196                 goto out_kcore_close;
2197
2198         if (kcore__copy_hdr(&kcore, &extract, count))
2199                 goto out_extract_close;
2200
2201         if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
2202                 goto out_extract_close;
2203
2204         sz = kcore__write(&extract);
2205         if (sz < 0 || sz > offset)
2206                 goto out_extract_close;
2207
2208         if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
2209                 goto out_extract_close;
2210
2211         err = 0;
2212
2213 out_extract_close:
2214         kcore__close(&extract);
2215         if (err)
2216                 unlink(kce->extract_filename);
2217 out_kcore_close:
2218         kcore__close(&kcore);
2219
2220         return err;
2221 }
2222
2223 void kcore_extract__delete(struct kcore_extract *kce)
2224 {
2225         unlink(kce->extract_filename);
2226 }
2227
2228 #ifdef HAVE_GELF_GETNOTE_SUPPORT
2229
2230 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2231 {
2232         if (!base_off)
2233                 return;
2234
2235         if (tmp->bit32)
2236                 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2237                         tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2238                         tmp->addr.a32[SDT_NOTE_IDX_BASE];
2239         else
2240                 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2241                         tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2242                         tmp->addr.a64[SDT_NOTE_IDX_BASE];
2243 }
2244
2245 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2246                               GElf_Addr base_off)
2247 {
2248         if (!base_off)
2249                 return;
2250
2251         if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2252                 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2253         else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2254                 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2255 }
2256
2257 /**
2258  * populate_sdt_note : Parse raw data and identify SDT note
2259  * @elf: elf of the opened file
2260  * @data: raw data of a section with description offset applied
2261  * @len: note description size
2262  * @type: type of the note
2263  * @sdt_notes: List to add the SDT note
2264  *
2265  * Responsible for parsing the @data in section .note.stapsdt in @elf and
2266  * if its an SDT note, it appends to @sdt_notes list.
2267  */
2268 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2269                              struct list_head *sdt_notes)
2270 {
2271         const char *provider, *name, *args;
2272         struct sdt_note *tmp = NULL;
2273         GElf_Ehdr ehdr;
2274         GElf_Shdr shdr;
2275         int ret = -EINVAL;
2276
2277         union {
2278                 Elf64_Addr a64[NR_ADDR];
2279                 Elf32_Addr a32[NR_ADDR];
2280         } buf;
2281
2282         Elf_Data dst = {
2283                 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2284                 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2285                 .d_off = 0, .d_align = 0
2286         };
2287         Elf_Data src = {
2288                 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2289                 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2290                 .d_align = 0
2291         };
2292
2293         tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2294         if (!tmp) {
2295                 ret = -ENOMEM;
2296                 goto out_err;
2297         }
2298
2299         INIT_LIST_HEAD(&tmp->note_list);
2300
2301         if (len < dst.d_size + 3)
2302                 goto out_free_note;
2303
2304         /* Translation from file representation to memory representation */
2305         if (gelf_xlatetom(*elf, &dst, &src,
2306                           elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2307                 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2308                 goto out_free_note;
2309         }
2310
2311         /* Populate the fields of sdt_note */
2312         provider = data + dst.d_size;
2313
2314         name = (const char *)memchr(provider, '\0', data + len - provider);
2315         if (name++ == NULL)
2316                 goto out_free_note;
2317
2318         tmp->provider = strdup(provider);
2319         if (!tmp->provider) {
2320                 ret = -ENOMEM;
2321                 goto out_free_note;
2322         }
2323         tmp->name = strdup(name);
2324         if (!tmp->name) {
2325                 ret = -ENOMEM;
2326                 goto out_free_prov;
2327         }
2328
2329         args = memchr(name, '\0', data + len - name);
2330
2331         /*
2332          * There is no argument if:
2333          * - We reached the end of the note;
2334          * - There is not enough room to hold a potential string;
2335          * - The argument string is empty or just contains ':'.
2336          */
2337         if (args == NULL || data + len - args < 2 ||
2338                 args[1] == ':' || args[1] == '\0')
2339                 tmp->args = NULL;
2340         else {
2341                 tmp->args = strdup(++args);
2342                 if (!tmp->args) {
2343                         ret = -ENOMEM;
2344                         goto out_free_name;
2345                 }
2346         }
2347
2348         if (gelf_getclass(*elf) == ELFCLASS32) {
2349                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2350                 tmp->bit32 = true;
2351         } else {
2352                 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2353                 tmp->bit32 = false;
2354         }
2355
2356         if (!gelf_getehdr(*elf, &ehdr)) {
2357                 pr_debug("%s : cannot get elf header.\n", __func__);
2358                 ret = -EBADF;
2359                 goto out_free_args;
2360         }
2361
2362         /* Adjust the prelink effect :
2363          * Find out the .stapsdt.base section.
2364          * This scn will help us to handle prelinking (if present).
2365          * Compare the retrieved file offset of the base section with the
2366          * base address in the description of the SDT note. If its different,
2367          * then accordingly, adjust the note location.
2368          */
2369         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2370                 sdt_adjust_loc(tmp, shdr.sh_offset);
2371
2372         /* Adjust reference counter offset */
2373         if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2374                 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2375
2376         list_add_tail(&tmp->note_list, sdt_notes);
2377         return 0;
2378
2379 out_free_args:
2380         zfree(&tmp->args);
2381 out_free_name:
2382         zfree(&tmp->name);
2383 out_free_prov:
2384         zfree(&tmp->provider);
2385 out_free_note:
2386         free(tmp);
2387 out_err:
2388         return ret;
2389 }
2390
2391 /**
2392  * construct_sdt_notes_list : constructs a list of SDT notes
2393  * @elf : elf to look into
2394  * @sdt_notes : empty list_head
2395  *
2396  * Scans the sections in 'elf' for the section
2397  * .note.stapsdt. It, then calls populate_sdt_note to find
2398  * out the SDT events and populates the 'sdt_notes'.
2399  */
2400 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2401 {
2402         GElf_Ehdr ehdr;
2403         Elf_Scn *scn = NULL;
2404         Elf_Data *data;
2405         GElf_Shdr shdr;
2406         size_t shstrndx, next;
2407         GElf_Nhdr nhdr;
2408         size_t name_off, desc_off, offset;
2409         int ret = 0;
2410
2411         if (gelf_getehdr(elf, &ehdr) == NULL) {
2412                 ret = -EBADF;
2413                 goto out_ret;
2414         }
2415         if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2416                 ret = -EBADF;
2417                 goto out_ret;
2418         }
2419
2420         /* Look for the required section */
2421         scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2422         if (!scn) {
2423                 ret = -ENOENT;
2424                 goto out_ret;
2425         }
2426
2427         if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2428                 ret = -ENOENT;
2429                 goto out_ret;
2430         }
2431
2432         data = elf_getdata(scn, NULL);
2433
2434         /* Get the SDT notes */
2435         for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2436                                               &desc_off)) > 0; offset = next) {
2437                 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2438                     !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2439                             sizeof(SDT_NOTE_NAME))) {
2440                         /* Check the type of the note */
2441                         if (nhdr.n_type != SDT_NOTE_TYPE)
2442                                 goto out_ret;
2443
2444                         ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2445                                                 nhdr.n_descsz, sdt_notes);
2446                         if (ret < 0)
2447                                 goto out_ret;
2448                 }
2449         }
2450         if (list_empty(sdt_notes))
2451                 ret = -ENOENT;
2452
2453 out_ret:
2454         return ret;
2455 }
2456
2457 /**
2458  * get_sdt_note_list : Wrapper to construct a list of sdt notes
2459  * @head : empty list_head
2460  * @target : file to find SDT notes from
2461  *
2462  * This opens the file, initializes
2463  * the ELF and then calls construct_sdt_notes_list.
2464  */
2465 int get_sdt_note_list(struct list_head *head, const char *target)
2466 {
2467         Elf *elf;
2468         int fd, ret;
2469
2470         fd = open(target, O_RDONLY);
2471         if (fd < 0)
2472                 return -EBADF;
2473
2474         elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2475         if (!elf) {
2476                 ret = -EBADF;
2477                 goto out_close;
2478         }
2479         ret = construct_sdt_notes_list(elf, head);
2480         elf_end(elf);
2481 out_close:
2482         close(fd);
2483         return ret;
2484 }
2485
2486 /**
2487  * cleanup_sdt_note_list : free the sdt notes' list
2488  * @sdt_notes: sdt notes' list
2489  *
2490  * Free up the SDT notes in @sdt_notes.
2491  * Returns the number of SDT notes free'd.
2492  */
2493 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2494 {
2495         struct sdt_note *tmp, *pos;
2496         int nr_free = 0;
2497
2498         list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2499                 list_del_init(&pos->note_list);
2500                 zfree(&pos->args);
2501                 zfree(&pos->name);
2502                 zfree(&pos->provider);
2503                 free(pos);
2504                 nr_free++;
2505         }
2506         return nr_free;
2507 }
2508
2509 /**
2510  * sdt_notes__get_count: Counts the number of sdt events
2511  * @start: list_head to sdt_notes list
2512  *
2513  * Returns the number of SDT notes in a list
2514  */
2515 int sdt_notes__get_count(struct list_head *start)
2516 {
2517         struct sdt_note *sdt_ptr;
2518         int count = 0;
2519
2520         list_for_each_entry(sdt_ptr, start, note_list)
2521                 count++;
2522         return count;
2523 }
2524 #endif
2525
2526 void symbol__elf_init(void)
2527 {
2528         elf_version(EV_CURRENT);
2529 }