tools/perf/util/symbol.c

   1 #include <dirent.h>
   2 #include <errno.h>
   3 #include <stdlib.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <sys/types.h>
   7 #include <sys/stat.h>
   8 #include <sys/param.h>
   9 #include <fcntl.h>
  10 #include <unistd.h>
  11 #include <inttypes.h>
  12 #include "build-id.h"
  13 #include "util.h"
  14 #include "debug.h"
  15 #include "machine.h"
  16 #include "symbol.h"
  17 #include "strlist.h"
  18
  19 #include <elf.h>
  20 #include <limits.h>
  21 #include <sys/utsname.h>
  22
  23 #ifndef KSYM_NAME_LEN
  24 #define KSYM_NAME_LEN 256
  25 #endif
  26
  27 static int dso__load_kernel_sym(struct dso *dso, struct map *map,
  28                                 symbol_filter_t filter);
  29 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map,
  30                         symbol_filter_t filter);
  31 int vmlinux_path__nr_entries;
  32 char **vmlinux_path;
  33
  34 struct symbol_conf symbol_conf = {
  35         .use_modules      = true,
  36         .try_vmlinux_path = true,
  37         .annotate_src     = true,
  38         .demangle         = true,
  39         .symfs            = "",
  40 };
  41
  42 static enum dso_binary_type binary_type_symtab[] = {
  43         DSO_BINARY_TYPE__KALLSYMS,
  44         DSO_BINARY_TYPE__GUEST_KALLSYMS,
  45         DSO_BINARY_TYPE__JAVA_JIT,
  46         DSO_BINARY_TYPE__DEBUGLINK,
  47         DSO_BINARY_TYPE__BUILD_ID_CACHE,
  48         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
  49         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
  50         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
  51         DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
  52         DSO_BINARY_TYPE__GUEST_KMODULE,
  53         DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE,
  54         DSO_BINARY_TYPE__NOT_FOUND,
  55 };
  56
  57 #define DSO_BINARY_TYPE__SYMTAB_CNT ARRAY_SIZE(binary_type_symtab)
  58
  59 bool symbol_type__is_a(char symbol_type, enum map_type map_type)
  60 {
  61         symbol_type = toupper(symbol_type);
  62
  63         switch (map_type) {
  64         case MAP__FUNCTION:
  65                 return symbol_type == 'T' || symbol_type == 'W';
  66         case MAP__VARIABLE:
  67                 return symbol_type == 'D';
  68         default:
  69                 return false;
  70         }
  71 }
  72
  73 static int prefix_underscores_count(const char *str)
  74 {
  75         const char *tail = str;
  76
  77         while (*tail == '_')
  78                 tail++;
  79
  80         return tail - str;
  81 }
  82
  83 #define SYMBOL_A 0
  84 #define SYMBOL_B 1
  85
  86 static int choose_best_symbol(struct symbol *syma, struct symbol *symb)
  87 {
  88         s64 a;
  89         s64 b;
  90         size_t na, nb;
  91
  92         /* Prefer a symbol with non zero length */
  93         a = syma->end - syma->start;
  94         b = symb->end - symb->start;
  95         if ((b == 0) && (a > 0))
  96                 return SYMBOL_A;
  97         else if ((a == 0) && (b > 0))
  98                 return SYMBOL_B;
  99
 100         /* Prefer a non weak symbol over a weak one */
 101         a = syma->binding == STB_WEAK;
 102         b = symb->binding == STB_WEAK;
 103         if (b && !a)
 104                 return SYMBOL_A;
 105         if (a && !b)
 106                 return SYMBOL_B;
 107
 108         /* Prefer a global symbol over a non global one */
 109         a = syma->binding == STB_GLOBAL;
 110         b = symb->binding == STB_GLOBAL;
 111         if (a && !b)
 112                 return SYMBOL_A;
 113         if (b && !a)
 114                 return SYMBOL_B;
 115
 116         /* Prefer a symbol with less underscores */
 117         a = prefix_underscores_count(syma->name);
 118         b = prefix_underscores_count(symb->name);
 119         if (b > a)
 120                 return SYMBOL_A;
 121         else if (a > b)
 122                 return SYMBOL_B;
 123
 124         /* Choose the symbol with the longest name */
 125         na = strlen(syma->name);
 126         nb = strlen(symb->name);
 127         if (na > nb)
 128                 return SYMBOL_A;
 129         else if (na < nb)
 130                 return SYMBOL_B;
 131
 132         /* Avoid "SyS" kernel syscall aliases */
 133         if (na >= 3 && !strncmp(syma->name, "SyS", 3))
 134                 return SYMBOL_B;
 135         if (na >= 10 && !strncmp(syma->name, "compat_SyS", 10))
 136                 return SYMBOL_B;
 137
 138         return SYMBOL_A;
 139 }
 140
 141 void symbols__fixup_duplicate(struct rb_root *symbols)
 142 {
 143         struct rb_node *nd;
 144         struct symbol *curr, *next;
 145
 146         nd = rb_first(symbols);
 147
 148         while (nd) {
 149                 curr = rb_entry(nd, struct symbol, rb_node);
 150 again:
 151                 nd = rb_next(&curr->rb_node);
 152                 next = rb_entry(nd, struct symbol, rb_node);
 153
 154                 if (!nd)
 155                         break;
 156
 157                 if (curr->start != next->start)
 158                         continue;
 159
 160                 if (choose_best_symbol(curr, next) == SYMBOL_A) {
 161                         rb_erase(&next->rb_node, symbols);
 162                         goto again;
 163                 } else {
 164                         nd = rb_next(&curr->rb_node);
 165                         rb_erase(&curr->rb_node, symbols);
 166                 }
 167         }
 168 }
 169
 170 void symbols__fixup_end(struct rb_root *symbols)
 171 {
 172         struct rb_node *nd, *prevnd = rb_first(symbols);
 173         struct symbol *curr, *prev;
 174
 175         if (prevnd == NULL)
 176                 return;
 177
 178         curr = rb_entry(prevnd, struct symbol, rb_node);
 179
 180         for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
 181                 prev = curr;
 182                 curr = rb_entry(nd, struct symbol, rb_node);
 183
 184                 if (prev->end == prev->start && prev->end != curr->start)
 185                         prev->end = curr->start - 1;
 186         }
 187
 188         /* Last entry */
 189         if (curr->end == curr->start)
 190                 curr->end = roundup(curr->start, 4096);
 191 }
 192
 193 void __map_groups__fixup_end(struct map_groups *mg, enum map_type type)
 194 {
 195         struct map *prev, *curr;
 196         struct rb_node *nd, *prevnd = rb_first(&mg->maps[type]);
 197
 198         if (prevnd == NULL)
 199                 return;
 200
 201         curr = rb_entry(prevnd, struct map, rb_node);
 202
 203         for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
 204                 prev = curr;
 205                 curr = rb_entry(nd, struct map, rb_node);
 206                 prev->end = curr->start - 1;
 207         }
 208
 209         /*
 210          * We still haven't the actual symbols, so guess the
 211          * last map final address.
 212          */
 213         curr->end = ~0ULL;
 214 }
 215
 216 struct symbol *symbol__new(u64 start, u64 len, u8 binding, const char *name)
 217 {
 218         size_t namelen = strlen(name) + 1;
 219         struct symbol *sym = calloc(1, (symbol_conf.priv_size +
 220                                         sizeof(*sym) + namelen));
 221         if (sym == NULL)
 222                 return NULL;
 223
 224         if (symbol_conf.priv_size)
 225                 sym = ((void *)sym) + symbol_conf.priv_size;
 226
 227         sym->start   = start;
 228         sym->end     = len ? start + len - 1 : start;
 229         sym->binding = binding;
 230         sym->namelen = namelen - 1;
 231
 232         pr_debug4("%s: %s %#" PRIx64 "-%#" PRIx64 "\n",
 233                   __func__, name, start, sym->end);
 234         memcpy(sym->name, name, namelen);
 235
 236         return sym;
 237 }
 238
 239 void symbol__delete(struct symbol *sym)
 240 {
 241         free(((void *)sym) - symbol_conf.priv_size);
 242 }
 243
 244 size_t symbol__fprintf(struct symbol *sym, FILE *fp)
 245 {
 246         return fprintf(fp, " %" PRIx64 "-%" PRIx64 " %c %s\n",
 247                        sym->start, sym->end,
 248                        sym->binding == STB_GLOBAL ? 'g' :
 249                        sym->binding == STB_LOCAL  ? 'l' : 'w',
 250                        sym->name);
 251 }
 252
 253 size_t symbol__fprintf_symname_offs(const struct symbol *sym,
 254                                     const struct addr_location *al, FILE *fp)
 255 {
 256         unsigned long offset;
 257         size_t length;
 258
 259         if (sym && sym->name) {
 260                 length = fprintf(fp, "%s", sym->name);
 261                 if (al) {
 262                         if (al->addr < sym->end)
 263                                 offset = al->addr - sym->start;
 264                         else
 265                                 offset = al->addr - al->map->start - sym->start;
 266                         length += fprintf(fp, "+0x%lx", offset);
 267                 }
 268                 return length;
 269         } else
 270                 return fprintf(fp, "[unknown]");
 271 }
 272
 273 size_t symbol__fprintf_symname(const struct symbol *sym, FILE *fp)
 274 {
 275         return symbol__fprintf_symname_offs(sym, NULL, fp);
 276 }
 277
 278 void symbols__delete(struct rb_root *symbols)
 279 {
 280         struct symbol *pos;
 281         struct rb_node *next = rb_first(symbols);
 282
 283         while (next) {
 284                 pos = rb_entry(next, struct symbol, rb_node);
 285                 next = rb_next(&pos->rb_node);
 286                 rb_erase(&pos->rb_node, symbols);
 287                 symbol__delete(pos);
 288         }
 289 }
 290
 291 void symbols__insert(struct rb_root *symbols, struct symbol *sym)
 292 {
 293         struct rb_node **p = &symbols->rb_node;
 294         struct rb_node *parent = NULL;
 295         const u64 ip = sym->start;
 296         struct symbol *s;
 297
 298         while (*p != NULL) {
 299                 parent = *p;
 300                 s = rb_entry(parent, struct symbol, rb_node);
 301                 if (ip < s->start)
 302                         p = &(*p)->rb_left;
 303                 else
 304                         p = &(*p)->rb_right;
 305         }
 306         rb_link_node(&sym->rb_node, parent, p);
 307         rb_insert_color(&sym->rb_node, symbols);
 308 }
 309
 310 static struct symbol *symbols__find(struct rb_root *symbols, u64 ip)
 311 {
 312         struct rb_node *n;
 313
 314         if (symbols == NULL)
 315                 return NULL;
 316
 317         n = symbols->rb_node;
 318
 319         while (n) {
 320                 struct symbol *s = rb_entry(n, struct symbol, rb_node);
 321
 322                 if (ip < s->start)
 323                         n = n->rb_left;
 324                 else if (ip > s->end)
 325                         n = n->rb_right;
 326                 else
 327                         return s;
 328         }
 329
 330         return NULL;
 331 }
 332
 333 static struct symbol *symbols__first(struct rb_root *symbols)
 334 {
 335         struct rb_node *n = rb_first(symbols);
 336
 337         if (n)
 338                 return rb_entry(n, struct symbol, rb_node);
 339
 340         return NULL;
 341 }
 342
 343 struct symbol_name_rb_node {
 344         struct rb_node  rb_node;
 345         struct symbol   sym;
 346 };
 347
 348 static void symbols__insert_by_name(struct rb_root *symbols, struct symbol *sym)
 349 {
 350         struct rb_node **p = &symbols->rb_node;
 351         struct rb_node *parent = NULL;
 352         struct symbol_name_rb_node *symn, *s;
 353
 354         symn = container_of(sym, struct symbol_name_rb_node, sym);
 355
 356         while (*p != NULL) {
 357                 parent = *p;
 358                 s = rb_entry(parent, struct symbol_name_rb_node, rb_node);
 359                 if (strcmp(sym->name, s->sym.name) < 0)
 360                         p = &(*p)->rb_left;
 361                 else
 362                         p = &(*p)->rb_right;
 363         }
 364         rb_link_node(&symn->rb_node, parent, p);
 365         rb_insert_color(&symn->rb_node, symbols);
 366 }
 367
 368 static void symbols__sort_by_name(struct rb_root *symbols,
 369                                   struct rb_root *source)
 370 {
 371         struct rb_node *nd;
 372
 373         for (nd = rb_first(source); nd; nd = rb_next(nd)) {
 374                 struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
 375                 symbols__insert_by_name(symbols, pos);
 376         }
 377 }
 378
 379 static struct symbol *symbols__find_by_name(struct rb_root *symbols,
 380                                             const char *name)
 381 {
 382         struct rb_node *n;
 383
 384         if (symbols == NULL)
 385                 return NULL;
 386
 387         n = symbols->rb_node;
 388
 389         while (n) {
 390                 struct symbol_name_rb_node *s;
 391                 int cmp;
 392
 393                 s = rb_entry(n, struct symbol_name_rb_node, rb_node);
 394                 cmp = strcmp(name, s->sym.name);
 395
 396                 if (cmp < 0)
 397                         n = n->rb_left;
 398                 else if (cmp > 0)
 399                         n = n->rb_right;
 400                 else
 401                         return &s->sym;
 402         }
 403
 404         return NULL;
 405 }
 406
 407 struct symbol *dso__find_symbol(struct dso *dso,
 408                                 enum map_type type, u64 addr)
 409 {
 410         return symbols__find(&dso->symbols[type], addr);
 411 }
 412
 413 struct symbol *dso__first_symbol(struct dso *dso, enum map_type type)
 414 {
 415         return symbols__first(&dso->symbols[type]);
 416 }
 417
 418 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
 419                                         const char *name)
 420 {
 421         return symbols__find_by_name(&dso->symbol_names[type], name);
 422 }
 423
 424 void dso__sort_by_name(struct dso *dso, enum map_type type)
 425 {
 426         dso__set_sorted_by_name(dso, type);
 427         return symbols__sort_by_name(&dso->symbol_names[type],
 428                                      &dso->symbols[type]);
 429 }
 430
 431 size_t dso__fprintf_symbols_by_name(struct dso *dso,
 432                                     enum map_type type, FILE *fp)
 433 {
 434         size_t ret = 0;
 435         struct rb_node *nd;
 436         struct symbol_name_rb_node *pos;
 437
 438         for (nd = rb_first(&dso->symbol_names[type]); nd; nd = rb_next(nd)) {
 439                 pos = rb_entry(nd, struct symbol_name_rb_node, rb_node);
 440                 fprintf(fp, "%s\n", pos->sym.name);
 441         }
 442
 443         return ret;
 444 }
 445
 446 int kallsyms__parse(const char *filename, void *arg,
 447                     int (*process_symbol)(void *arg, const char *name,
 448                                           char type, u64 start))
 449 {
 450         char *line = NULL;
 451         size_t n;
 452         int err = -1;
 453         FILE *file = fopen(filename, "r");
 454
 455         if (file == NULL)
 456                 goto out_failure;
 457
 458         err = 0;
 459
 460         while (!feof(file)) {
 461                 u64 start;
 462                 int line_len, len;
 463                 char symbol_type;
 464                 char *symbol_name;
 465
 466                 line_len = getline(&line, &n, file);
 467                 if (line_len < 0 || !line)
 468                         break;
 469
 470                 line[--line_len] = '\0'; /* \n */
 471
 472                 len = hex2u64(line, &start);
 473
 474                 len++;
 475                 if (len + 2 >= line_len)
 476                         continue;
 477
 478                 symbol_type = line[len];
 479                 len += 2;
 480                 symbol_name = line + len;
 481                 len = line_len - len;
 482
 483                 if (len >= KSYM_NAME_LEN) {
 484                         err = -1;
 485                         break;
 486                 }
 487
 488                 err = process_symbol(arg, symbol_name,
 489                                      symbol_type, start);
 490                 if (err)
 491                         break;
 492         }
 493
 494         free(line);
 495         fclose(file);
 496         return err;
 497
 498 out_failure:
 499         return -1;
 500 }
 501
 502 struct process_kallsyms_args {
 503         struct map *map;
 504         struct dso *dso;
 505 };
 506
 507 static u8 kallsyms2elf_type(char type)
 508 {
 509         if (type == 'W')
 510                 return STB_WEAK;
 511
 512         return isupper(type) ? STB_GLOBAL : STB_LOCAL;
 513 }
 514
 515 static int map__process_kallsym_symbol(void *arg, const char *name,
 516                                        char type, u64 start)
 517 {
 518         struct symbol *sym;
 519         struct process_kallsyms_args *a = arg;
 520         struct rb_root *root = &a->dso->symbols[a->map->type];
 521
 522         if (!symbol_type__is_a(type, a->map->type))
 523                 return 0;
 524
 525         /*
 526          * module symbols are not sorted so we add all
 527          * symbols, setting length to 0, and rely on
 528          * symbols__fixup_end() to fix it up.
 529          */
 530         sym = symbol__new(start, 0, kallsyms2elf_type(type), name);
 531         if (sym == NULL)
 532                 return -ENOMEM;
 533         /*
 534          * We will pass the symbols to the filter later, in
 535          * map__split_kallsyms, when we have split the maps per module
 536          */
 537         symbols__insert(root, sym);
 538
 539         return 0;
 540 }
 541
 542 /*
 543  * Loads the function entries in /proc/kallsyms into kernel_map->dso,
 544  * so that we can in the next step set the symbol ->end address and then
 545  * call kernel_maps__split_kallsyms.
 546  */
 547 static int dso__load_all_kallsyms(struct dso *dso, const char *filename,
 548                                   struct map *map)
 549 {
 550         struct process_kallsyms_args args = { .map = map, .dso = dso, };
 551         return kallsyms__parse(filename, &args, map__process_kallsym_symbol);
 552 }
 553
 554 static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map,
 555                                          symbol_filter_t filter)
 556 {
 557         struct map_groups *kmaps = map__kmap(map)->kmaps;
 558         struct map *curr_map;
 559         struct symbol *pos;
 560         int count = 0, moved = 0;
 561         struct rb_root *root = &dso->symbols[map->type];
 562         struct rb_node *next = rb_first(root);
 563
 564         while (next) {
 565                 char *module;
 566
 567                 pos = rb_entry(next, struct symbol, rb_node);
 568                 next = rb_next(&pos->rb_node);
 569
 570                 module = strchr(pos->name, '\t');
 571                 if (module)
 572                         *module = '\0';
 573
 574                 curr_map = map_groups__find(kmaps, map->type, pos->start);
 575
 576                 if (!curr_map || (filter && filter(curr_map, pos))) {
 577                         rb_erase(&pos->rb_node, root);
 578                         symbol__delete(pos);
 579                 } else {
 580                         pos->start -= curr_map->start - curr_map->pgoff;
 581                         if (pos->end)
 582                                 pos->end -= curr_map->start - curr_map->pgoff;
 583                         if (curr_map != map) {
 584                                 rb_erase(&pos->rb_node, root);
 585                                 symbols__insert(
 586                                         &curr_map->dso->symbols[curr_map->type],
 587                                         pos);
 588                                 ++moved;
 589                         } else {
 590                                 ++count;
 591                         }
 592                 }
 593         }
 594
 595         /* Symbols have been adjusted */
 596         dso->adjust_symbols = 1;
 597
 598         return count + moved;
 599 }
 600
 601 /*
 602  * Split the symbols into maps, making sure there are no overlaps, i.e. the
 603  * kernel range is broken in several maps, named [kernel].N, as we don't have
 604  * the original ELF section names vmlinux have.
 605  */
 606 static int dso__split_kallsyms(struct dso *dso, struct map *map,
 607                                symbol_filter_t filter)
 608 {
 609         struct map_groups *kmaps = map__kmap(map)->kmaps;
 610         struct machine *machine = kmaps->machine;
 611         struct map *curr_map = map;
 612         struct symbol *pos;
 613         int count = 0, moved = 0;
 614         struct rb_root *root = &dso->symbols[map->type];
 615         struct rb_node *next = rb_first(root);
 616         int kernel_range = 0;
 617
 618         while (next) {
 619                 char *module;
 620
 621                 pos = rb_entry(next, struct symbol, rb_node);
 622                 next = rb_next(&pos->rb_node);
 623
 624                 module = strchr(pos->name, '\t');
 625                 if (module) {
 626                         if (!symbol_conf.use_modules)
 627                                 goto discard_symbol;
 628
 629                         *module++ = '\0';
 630
 631                         if (strcmp(curr_map->dso->short_name, module)) {
 632                                 if (curr_map != map &&
 633                                     dso->kernel == DSO_TYPE_GUEST_KERNEL &&
 634                                     machine__is_default_guest(machine)) {
 635                                         /*
 636                                          * We assume all symbols of a module are
 637                                          * continuous in * kallsyms, so curr_map
 638                                          * points to a module and all its
 639                                          * symbols are in its kmap. Mark it as
 640                                          * loaded.
 641                                          */
 642                                         dso__set_loaded(curr_map->dso,
 643                                                         curr_map->type);
 644                                 }
 645
 646                                 curr_map = map_groups__find_by_name(kmaps,
 647                                                         map->type, module);
 648                                 if (curr_map == NULL) {
 649                                         pr_debug("%s/proc/{kallsyms,modules} "
 650                                                  "inconsistency while looking "
 651                                                  "for \"%s\" module!\n",
 652                                                  machine->root_dir, module);
 653                                         curr_map = map;
 654                                         goto discard_symbol;
 655                                 }
 656
 657                                 if (curr_map->dso->loaded &&
 658                                     !machine__is_default_guest(machine))
 659                                         goto discard_symbol;
 660                         }
 661                         /*
 662                          * So that we look just like we get from .ko files,
 663                          * i.e. not prelinked, relative to map->start.
 664                          */
 665                         pos->start = curr_map->map_ip(curr_map, pos->start);
 666                         pos->end   = curr_map->map_ip(curr_map, pos->end);
 667                 } else if (curr_map != map) {
 668                         char dso_name[PATH_MAX];
 669                         struct dso *ndso;
 670
 671                         if (count == 0) {
 672                                 curr_map = map;
 673                                 goto filter_symbol;
 674                         }
 675
 676                         if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 677                                 snprintf(dso_name, sizeof(dso_name),
 678                                         "[guest.kernel].%d",
 679                                         kernel_range++);
 680                         else
 681                                 snprintf(dso_name, sizeof(dso_name),
 682                                         "[kernel].%d",
 683                                         kernel_range++);
 684
 685                         ndso = dso__new(dso_name);
 686                         if (ndso == NULL)
 687                                 return -1;
 688
 689                         ndso->kernel = dso->kernel;
 690
 691                         curr_map = map__new2(pos->start, ndso, map->type);
 692                         if (curr_map == NULL) {
 693                                 dso__delete(ndso);
 694                                 return -1;
 695                         }
 696
 697                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
 698                         map_groups__insert(kmaps, curr_map);
 699                         ++kernel_range;
 700                 }
 701 filter_symbol:
 702                 if (filter && filter(curr_map, pos)) {
 703 discard_symbol:         rb_erase(&pos->rb_node, root);
 704                         symbol__delete(pos);
 705                 } else {
 706                         if (curr_map != map) {
 707                                 rb_erase(&pos->rb_node, root);
 708                                 symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
 709                                 ++moved;
 710                         } else
 711                                 ++count;
 712                 }
 713         }
 714
 715         if (curr_map != map &&
 716             dso->kernel == DSO_TYPE_GUEST_KERNEL &&
 717             machine__is_default_guest(kmaps->machine)) {
 718                 dso__set_loaded(curr_map->dso, curr_map->type);
 719         }
 720
 721         return count + moved;
 722 }
 723
 724 bool symbol__restricted_filename(const char *filename,
 725                                  const char *restricted_filename)
 726 {
 727         bool restricted = false;
 728
 729         if (symbol_conf.kptr_restrict) {
 730                 char *r = realpath(filename, NULL);
 731
 732                 if (r != NULL) {
 733                         restricted = strcmp(r, restricted_filename) == 0;
 734                         free(r);
 735                         return restricted;
 736                 }
 737         }
 738
 739         return restricted;
 740 }
 741
 742 struct kcore_mapfn_data {
 743         struct dso *dso;
 744         enum map_type type;
 745         struct list_head maps;
 746 };
 747
 748 static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
 749 {
 750         struct kcore_mapfn_data *md = data;
 751         struct map *map;
 752
 753         map = map__new2(start, md->dso, md->type);
 754         if (map == NULL)
 755                 return -ENOMEM;
 756
 757         map->end = map->start + len;
 758         map->pgoff = pgoff;
 759
 760         list_add(&map->node, &md->maps);
 761
 762         return 0;
 763 }
 764
 765 /*
 766  * If kallsyms is referenced by name then we look for kcore in the same
 767  * directory.
 768  */
 769 static bool kcore_filename_from_kallsyms_filename(char *kcore_filename,
 770                                                   const char *kallsyms_filename)
 771 {
 772         char *name;
 773
 774         strcpy(kcore_filename, kallsyms_filename);
 775         name = strrchr(kcore_filename, '/');
 776         if (!name)
 777                 return false;
 778
 779         if (!strcmp(name, "/kallsyms")) {
 780                 strcpy(name, "/kcore");
 781                 return true;
 782         }
 783
 784         return false;
 785 }
 786
 787 static int dso__load_kcore(struct dso *dso, struct map *map,
 788                            const char *kallsyms_filename)
 789 {
 790         struct map_groups *kmaps = map__kmap(map)->kmaps;
 791         struct machine *machine = kmaps->machine;
 792         struct kcore_mapfn_data md;
 793         struct map *old_map, *new_map, *replacement_map = NULL;
 794         bool is_64_bit;
 795         int err, fd;
 796         char kcore_filename[PATH_MAX];
 797         struct symbol *sym;
 798
 799         /* This function requires that the map is the kernel map */
 800         if (map != machine->vmlinux_maps[map->type])
 801                 return -EINVAL;
 802
 803         if (!kcore_filename_from_kallsyms_filename(kcore_filename,
 804                                                    kallsyms_filename))
 805                 return -EINVAL;
 806
 807         md.dso = dso;
 808         md.type = map->type;
 809         INIT_LIST_HEAD(&md.maps);
 810
 811         fd = open(kcore_filename, O_RDONLY);
 812         if (fd < 0)
 813                 return -EINVAL;
 814
 815         /* Read new maps into temporary lists */
 816         err = file__read_maps(fd, md.type == MAP__FUNCTION, kcore_mapfn, &md,
 817                               &is_64_bit);
 818         if (err)
 819                 goto out_err;
 820
 821         if (list_empty(&md.maps)) {
 822                 err = -EINVAL;
 823                 goto out_err;
 824         }
 825
 826         /* Remove old maps */
 827         old_map = map_groups__first(kmaps, map->type);
 828         while (old_map) {
 829                 struct map *next = map_groups__next(old_map);
 830
 831                 if (old_map != map)
 832                         map_groups__remove(kmaps, old_map);
 833                 old_map = next;
 834         }
 835
 836         /* Find the kernel map using the first symbol */
 837         sym = dso__first_symbol(dso, map->type);
 838         list_for_each_entry(new_map, &md.maps, node) {
 839                 if (sym && sym->start >= new_map->start &&
 840                     sym->start < new_map->end) {
 841                         replacement_map = new_map;
 842                         break;
 843                 }
 844         }
 845
 846         if (!replacement_map)
 847                 replacement_map = list_entry(md.maps.next, struct map, node);
 848
 849         /* Add new maps */
 850         while (!list_empty(&md.maps)) {
 851                 new_map = list_entry(md.maps.next, struct map, node);
 852                 list_del(&new_map->node);
 853                 if (new_map == replacement_map) {
 854                         map->start      = new_map->start;
 855                         map->end        = new_map->end;
 856                         map->pgoff      = new_map->pgoff;
 857                         map->map_ip     = new_map->map_ip;
 858                         map->unmap_ip   = new_map->unmap_ip;
 859                         map__delete(new_map);
 860                         /* Ensure maps are correctly ordered */
 861                         map_groups__remove(kmaps, map);
 862                         map_groups__insert(kmaps, map);
 863                 } else {
 864                         map_groups__insert(kmaps, new_map);
 865                 }
 866         }
 867
 868         /*
 869          * Set the data type and long name so that kcore can be read via
 870          * dso__data_read_addr().
 871          */
 872         if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 873                 dso->data_type = DSO_BINARY_TYPE__GUEST_KCORE;
 874         else
 875                 dso->data_type = DSO_BINARY_TYPE__KCORE;
 876         dso__set_long_name(dso, strdup(kcore_filename));
 877
 878         close(fd);
 879
 880         if (map->type == MAP__FUNCTION)
 881                 pr_debug("Using %s for kernel object code\n", kcore_filename);
 882         else
 883                 pr_debug("Using %s for kernel data\n", kcore_filename);
 884
 885         return 0;
 886
 887 out_err:
 888         while (!list_empty(&md.maps)) {
 889                 map = list_entry(md.maps.next, struct map, node);
 890                 list_del(&map->node);
 891                 map__delete(map);
 892         }
 893         close(fd);
 894         return -EINVAL;
 895 }
 896
 897 int dso__load_kallsyms(struct dso *dso, const char *filename,
 898                        struct map *map, symbol_filter_t filter)
 899 {
 900         if (symbol__restricted_filename(filename, "/proc/kallsyms"))
 901                 return -1;
 902
 903         if (dso__load_all_kallsyms(dso, filename, map) < 0)
 904                 return -1;
 905
 906         symbols__fixup_duplicate(&dso->symbols[map->type]);
 907         symbols__fixup_end(&dso->symbols[map->type]);
 908
 909         if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 910                 dso->symtab_type = DSO_BINARY_TYPE__GUEST_KALLSYMS;
 911         else
 912                 dso->symtab_type = DSO_BINARY_TYPE__KALLSYMS;
 913
 914         if (!dso__load_kcore(dso, map, filename))
 915                 return dso__split_kallsyms_for_kcore(dso, map, filter);
 916         else
 917                 return dso__split_kallsyms(dso, map, filter);
 918 }
 919
 920 static int dso__load_perf_map(struct dso *dso, struct map *map,
 921                               symbol_filter_t filter)
 922 {
 923         char *line = NULL;
 924         size_t n;
 925         FILE *file;
 926         int nr_syms = 0;
 927
 928         file = fopen(dso->long_name, "r");
 929         if (file == NULL)
 930                 goto out_failure;
 931
 932         while (!feof(file)) {
 933                 u64 start, size;
 934                 struct symbol *sym;
 935                 int line_len, len;
 936
 937                 line_len = getline(&line, &n, file);
 938                 if (line_len < 0)
 939                         break;
 940
 941                 if (!line)
 942                         goto out_failure;
 943
 944                 line[--line_len] = '\0'; /* \n */
 945
 946                 len = hex2u64(line, &start);
 947
 948                 len++;
 949                 if (len + 2 >= line_len)
 950                         continue;
 951
 952                 len += hex2u64(line + len, &size);
 953
 954                 len++;
 955                 if (len + 2 >= line_len)
 956                         continue;
 957
 958                 sym = symbol__new(start, size, STB_GLOBAL, line + len);
 959
 960                 if (sym == NULL)
 961                         goto out_delete_line;
 962
 963                 if (filter && filter(map, sym))
 964                         symbol__delete(sym);
 965                 else {
 966                         symbols__insert(&dso->symbols[map->type], sym);
 967                         nr_syms++;
 968                 }
 969         }
 970
 971         free(line);
 972         fclose(file);
 973
 974         return nr_syms;
 975
 976 out_delete_line:
 977         free(line);
 978 out_failure:
 979         return -1;
 980 }
 981
 982 int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter)
 983 {
 984         char *name;
 985         int ret = -1;
 986         u_int i;
 987         struct machine *machine;
 988         char *root_dir = (char *) "";
 989         int ss_pos = 0;
 990         struct symsrc ss_[2];
 991         struct symsrc *syms_ss = NULL, *runtime_ss = NULL;
 992
 993         dso__set_loaded(dso, map->type);
 994
 995         if (dso->kernel == DSO_TYPE_KERNEL)
 996                 return dso__load_kernel_sym(dso, map, filter);
 997         else if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 998                 return dso__load_guest_kernel_sym(dso, map, filter);
 999
1000         if (map->groups && map->groups->machine)
1001                 machine = map->groups->machine;
1002         else
1003                 machine = NULL;
1004
1005         dso->adjust_symbols = 0;
1006
1007         if (strncmp(dso->name, "/tmp/perf-", 10) == 0) {
1008                 struct stat st;
1009
1010                 if (lstat(dso->name, &st) < 0)
1011                         return -1;
1012
1013                 if (st.st_uid && (st.st_uid != geteuid())) {
1014                         pr_warning("File %s not owned by current user or root, "
1015                                 "ignoring it.\n", dso->name);
1016                         return -1;
1017                 }
1018
1019                 ret = dso__load_perf_map(dso, map, filter);
1020                 dso->symtab_type = ret > 0 ? DSO_BINARY_TYPE__JAVA_JIT :
1021                                              DSO_BINARY_TYPE__NOT_FOUND;
1022                 return ret;
1023         }
1024
1025         if (machine)
1026                 root_dir = machine->root_dir;
1027
1028         name = malloc(PATH_MAX);
1029         if (!name)
1030                 return -1;
1031
1032         /* Iterate over candidate debug images.
1033          * Keep track of "interesting" ones (those which have a symtab, dynsym,
1034          * and/or opd section) for processing.
1035          */
1036         for (i = 0; i < DSO_BINARY_TYPE__SYMTAB_CNT; i++) {
1037                 struct symsrc *ss = &ss_[ss_pos];
1038                 bool next_slot = false;
1039
1040                 enum dso_binary_type symtab_type = binary_type_symtab[i];
1041
1042                 if (dso__binary_type_file(dso, symtab_type,
1043                                           root_dir, name, PATH_MAX))
1044                         continue;
1045
1046                 /* Name is now the name of the next image to try */
1047                 if (symsrc__init(ss, dso, name, symtab_type) < 0)
1048                         continue;
1049
1050                 if (!syms_ss && symsrc__has_symtab(ss)) {
1051                         syms_ss = ss;
1052                         next_slot = true;
1053                 }
1054
1055                 if (!runtime_ss && symsrc__possibly_runtime(ss)) {
1056                         runtime_ss = ss;
1057                         next_slot = true;
1058                 }
1059
1060                 if (next_slot) {
1061                         ss_pos++;
1062
1063                         if (syms_ss && runtime_ss)
1064                                 break;
1065                 }
1066
1067         }
1068
1069         if (!runtime_ss && !syms_ss)
1070                 goto out_free;
1071
1072         if (runtime_ss && !syms_ss) {
1073                 syms_ss = runtime_ss;
1074         }
1075
1076         /* We'll have to hope for the best */
1077         if (!runtime_ss && syms_ss)
1078                 runtime_ss = syms_ss;
1079
1080         if (syms_ss) {
1081                 int km;
1082
1083                 km = dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE ||
1084                      dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE;
1085                 ret = dso__load_sym(dso, map, syms_ss, runtime_ss, filter, km);
1086         } else {
1087                 ret = -1;
1088         }
1089
1090         if (ret > 0) {
1091                 int nr_plt;
1092
1093                 nr_plt = dso__synthesize_plt_symbols(dso, runtime_ss, map, filter);
1094                 if (nr_plt > 0)
1095                         ret += nr_plt;
1096         }
1097
1098         for (; ss_pos > 0; ss_pos--)
1099                 symsrc__destroy(&ss_[ss_pos - 1]);
1100 out_free:
1101         free(name);
1102         if (ret < 0 && strstr(dso->name, " (deleted)") != NULL)
1103                 return 0;
1104         return ret;
1105 }
1106
1107 struct map *map_groups__find_by_name(struct map_groups *mg,
1108                                      enum map_type type, const char *name)
1109 {
1110         struct rb_node *nd;
1111
1112         for (nd = rb_first(&mg->maps[type]); nd; nd = rb_next(nd)) {
1113                 struct map *map = rb_entry(nd, struct map, rb_node);
1114
1115                 if (map->dso && strcmp(map->dso->short_name, name) == 0)
1116                         return map;
1117         }
1118
1119         return NULL;
1120 }
1121
1122 int dso__load_vmlinux(struct dso *dso, struct map *map,
1123                       const char *vmlinux, symbol_filter_t filter)
1124 {
1125         int err = -1;
1126         struct symsrc ss;
1127         char symfs_vmlinux[PATH_MAX];
1128         enum dso_binary_type symtab_type;
1129
1130         if (vmlinux[0] == '/')
1131                 snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s", vmlinux);
1132         else
1133                 snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s%s",
1134                          symbol_conf.symfs, vmlinux);
1135
1136         if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
1137                 symtab_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
1138         else
1139                 symtab_type = DSO_BINARY_TYPE__VMLINUX;
1140
1141         if (symsrc__init(&ss, dso, symfs_vmlinux, symtab_type))
1142                 return -1;
1143
1144         err = dso__load_sym(dso, map, &ss, &ss, filter, 0);
1145         symsrc__destroy(&ss);
1146
1147         if (err > 0) {
1148                 if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
1149                         dso->data_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
1150                 else
1151                         dso->data_type = DSO_BINARY_TYPE__VMLINUX;
1152                 dso__set_long_name(dso, (char *)vmlinux);
1153                 dso__set_loaded(dso, map->type);
1154                 pr_debug("Using %s for symbols\n", symfs_vmlinux);
1155         }
1156
1157         return err;
1158 }
1159
1160 int dso__load_vmlinux_path(struct dso *dso, struct map *map,
1161                            symbol_filter_t filter)
1162 {
1163         int i, err = 0;
1164         char *filename;
1165
1166         pr_debug("Looking at the vmlinux_path (%d entries long)\n",
1167                  vmlinux_path__nr_entries + 1);
1168
1169         filename = dso__build_id_filename(dso, NULL, 0);
1170         if (filename != NULL) {
1171                 err = dso__load_vmlinux(dso, map, filename, filter);
1172                 if (err > 0) {
1173                         dso->lname_alloc = 1;
1174                         goto out;
1175                 }
1176                 free(filename);
1177         }
1178
1179         for (i = 0; i < vmlinux_path__nr_entries; ++i) {
1180                 err = dso__load_vmlinux(dso, map, vmlinux_path[i], filter);
1181                 if (err > 0) {
1182                         dso__set_long_name(dso, strdup(vmlinux_path[i]));
1183                         dso->lname_alloc = 1;
1184                         break;
1185                 }
1186         }
1187 out:
1188         return err;
1189 }
1190
1191 static int dso__load_kernel_sym(struct dso *dso, struct map *map,
1192                                 symbol_filter_t filter)
1193 {
1194         int err;
1195         const char *kallsyms_filename = NULL;
1196         char *kallsyms_allocated_filename = NULL;
1197         /*
1198          * Step 1: if the user specified a kallsyms or vmlinux filename, use
1199          * it and only it, reporting errors to the user if it cannot be used.
1200          *
1201          * For instance, try to analyse an ARM perf.data file _without_ a
1202          * build-id, or if the user specifies the wrong path to the right
1203          * vmlinux file, obviously we can't fallback to another vmlinux (a
1204          * x86_86 one, on the machine where analysis is being performed, say),
1205          * or worse, /proc/kallsyms.
1206          *
1207          * If the specified file _has_ a build-id and there is a build-id
1208          * section in the perf.data file, we will still do the expected
1209          * validation in dso__load_vmlinux and will bail out if they don't
1210          * match.
1211          */
1212         if (symbol_conf.kallsyms_name != NULL) {
1213                 kallsyms_filename = symbol_conf.kallsyms_name;
1214                 goto do_kallsyms;
1215         }
1216
1217         if (symbol_conf.vmlinux_name != NULL) {
1218                 err = dso__load_vmlinux(dso, map,
1219                                         symbol_conf.vmlinux_name, filter);
1220                 if (err > 0) {
1221                         dso__set_long_name(dso,
1222                                            strdup(symbol_conf.vmlinux_name));
1223                         dso->lname_alloc = 1;
1224                         return err;
1225                 }
1226                 return err;
1227         }
1228
1229         if (vmlinux_path != NULL) {
1230                 err = dso__load_vmlinux_path(dso, map, filter);
1231                 if (err > 0)
1232                         return err;
1233         }
1234
1235         /* do not try local files if a symfs was given */
1236         if (symbol_conf.symfs[0] != 0)
1237                 return -1;
1238
1239         /*
1240          * Say the kernel DSO was created when processing the build-id header table,
1241          * we have a build-id, so check if it is the same as the running kernel,
1242          * using it if it is.
1243          */
1244         if (dso->has_build_id) {
1245                 u8 kallsyms_build_id[BUILD_ID_SIZE];
1246                 char sbuild_id[BUILD_ID_SIZE * 2 + 1];
1247
1248                 if (sysfs__read_build_id("/sys/kernel/notes", kallsyms_build_id,
1249                                          sizeof(kallsyms_build_id)) == 0) {
1250                         if (dso__build_id_equal(dso, kallsyms_build_id)) {
1251                                 kallsyms_filename = "/proc/kallsyms";
1252                                 goto do_kallsyms;
1253                         }
1254                 }
1255                 /*
1256                  * Now look if we have it on the build-id cache in
1257                  * $HOME/.debug/[kernel.kallsyms].
1258                  */
1259                 build_id__sprintf(dso->build_id, sizeof(dso->build_id),
1260                                   sbuild_id);
1261
1262                 if (asprintf(&kallsyms_allocated_filename,
1263                              "%s/.debug/[kernel.kallsyms]/%s",
1264                              getenv("HOME"), sbuild_id) == -1) {
1265                         pr_err("Not enough memory for kallsyms file lookup\n");
1266                         return -1;
1267                 }
1268
1269                 kallsyms_filename = kallsyms_allocated_filename;
1270
1271                 if (access(kallsyms_filename, F_OK)) {
1272                         pr_err("No kallsyms or vmlinux with build-id %s "
1273                                "was found\n", sbuild_id);
1274                         free(kallsyms_allocated_filename);
1275                         return -1;
1276                 }
1277         } else {
1278                 /*
1279                  * Last resort, if we don't have a build-id and couldn't find
1280                  * any vmlinux file, try the running kernel kallsyms table.
1281                  */
1282                 kallsyms_filename = "/proc/kallsyms";
1283         }
1284
1285 do_kallsyms:
1286         err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
1287         if (err > 0)
1288                 pr_debug("Using %s for symbols\n", kallsyms_filename);
1289         free(kallsyms_allocated_filename);
1290
1291         if (err > 0 && !dso__is_kcore(dso)) {
1292                 dso__set_long_name(dso, strdup("[kernel.kallsyms]"));
1293                 map__fixup_start(map);
1294                 map__fixup_end(map);
1295         }
1296
1297         return err;
1298 }
1299
1300 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map,
1301                                       symbol_filter_t filter)
1302 {
1303         int err;
1304         const char *kallsyms_filename = NULL;
1305         struct machine *machine;
1306         char path[PATH_MAX];
1307
1308         if (!map->groups) {
1309                 pr_debug("Guest kernel map hasn't the point to groups\n");
1310                 return -1;
1311         }
1312         machine = map->groups->machine;
1313
1314         if (machine__is_default_guest(machine)) {
1315                 /*
1316                  * if the user specified a vmlinux filename, use it and only
1317                  * it, reporting errors to the user if it cannot be used.
1318                  * Or use file guest_kallsyms inputted by user on commandline
1319                  */
1320                 if (symbol_conf.default_guest_vmlinux_name != NULL) {
1321                         err = dso__load_vmlinux(dso, map,
1322                                 symbol_conf.default_guest_vmlinux_name, filter);
1323                         return err;
1324                 }
1325
1326                 kallsyms_filename = symbol_conf.default_guest_kallsyms;
1327                 if (!kallsyms_filename)
1328                         return -1;
1329         } else {
1330                 sprintf(path, "%s/proc/kallsyms", machine->root_dir);
1331                 kallsyms_filename = path;
1332         }
1333
1334         err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
1335         if (err > 0)
1336                 pr_debug("Using %s for symbols\n", kallsyms_filename);
1337         if (err > 0 && !dso__is_kcore(dso)) {
1338                 machine__mmap_name(machine, path, sizeof(path));
1339                 dso__set_long_name(dso, strdup(path));
1340                 map__fixup_start(map);
1341                 map__fixup_end(map);
1342         }
1343
1344         return err;
1345 }
1346
1347 static void vmlinux_path__exit(void)
1348 {
1349         while (--vmlinux_path__nr_entries >= 0) {
1350                 free(vmlinux_path[vmlinux_path__nr_entries]);
1351                 vmlinux_path[vmlinux_path__nr_entries] = NULL;
1352         }
1353
1354         free(vmlinux_path);
1355         vmlinux_path = NULL;
1356 }
1357
1358 static int vmlinux_path__init(void)
1359 {
1360         struct utsname uts;
1361         char bf[PATH_MAX];
1362
1363         vmlinux_path = malloc(sizeof(char *) * 5);
1364         if (vmlinux_path == NULL)
1365                 return -1;
1366
1367         vmlinux_path[vmlinux_path__nr_entries] = strdup("vmlinux");
1368         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
1369                 goto out_fail;
1370         ++vmlinux_path__nr_entries;
1371         vmlinux_path[vmlinux_path__nr_entries] = strdup("/boot/vmlinux");
1372         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
1373                 goto out_fail;
1374         ++vmlinux_path__nr_entries;
1375
1376         /* only try running kernel version if no symfs was given */
1377         if (symbol_conf.symfs[0] != 0)
1378                 return 0;
1379
1380         if (uname(&uts) < 0)
1381                 return -1;
1382
1383         snprintf(bf, sizeof(bf), "/boot/vmlinux-%s", uts.release);
1384         vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
1385         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
1386                 goto out_fail;
1387         ++vmlinux_path__nr_entries;
1388         snprintf(bf, sizeof(bf), "/lib/modules/%s/build/vmlinux", uts.release);
1389         vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
1390         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
1391                 goto out_fail;
1392         ++vmlinux_path__nr_entries;
1393         snprintf(bf, sizeof(bf), "/usr/lib/debug/lib/modules/%s/vmlinux",
1394                  uts.release);
1395         vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
1396         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
1397                 goto out_fail;
1398         ++vmlinux_path__nr_entries;
1399
1400         return 0;
1401
1402 out_fail:
1403         vmlinux_path__exit();
1404         return -1;
1405 }
1406
1407 static int setup_list(struct strlist **list, const char *list_str,
1408                       const char *list_name)
1409 {
1410         if (list_str == NULL)
1411                 return 0;
1412
1413         *list = strlist__new(true, list_str);
1414         if (!*list) {
1415                 pr_err("problems parsing %s list\n", list_name);
1416                 return -1;
1417         }
1418         return 0;
1419 }
1420
1421 static bool symbol__read_kptr_restrict(void)
1422 {
1423         bool value = false;
1424
1425         if (geteuid() != 0) {
1426                 FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");
1427                 if (fp != NULL) {
1428                         char line[8];
1429
1430                         if (fgets(line, sizeof(line), fp) != NULL)
1431                                 value = atoi(line) != 0;
1432
1433                         fclose(fp);
1434                 }
1435         }
1436
1437         return value;
1438 }
1439
1440 int symbol__init(void)
1441 {
1442         const char *symfs;
1443
1444         if (symbol_conf.initialized)
1445                 return 0;
1446
1447         symbol_conf.priv_size = PERF_ALIGN(symbol_conf.priv_size, sizeof(u64));
1448
1449         symbol__elf_init();
1450
1451         if (symbol_conf.sort_by_name)
1452                 symbol_conf.priv_size += (sizeof(struct symbol_name_rb_node) -
1453                                           sizeof(struct symbol));
1454
1455         if (symbol_conf.try_vmlinux_path && vmlinux_path__init() < 0)
1456                 return -1;
1457
1458         if (symbol_conf.field_sep && *symbol_conf.field_sep == '.') {
1459                 pr_err("'.' is the only non valid --field-separator argument\n");
1460                 return -1;
1461         }
1462
1463         if (setup_list(&symbol_conf.dso_list,
1464                        symbol_conf.dso_list_str, "dso") < 0)
1465                 return -1;
1466
1467         if (setup_list(&symbol_conf.comm_list,
1468                        symbol_conf.comm_list_str, "comm") < 0)
1469                 goto out_free_dso_list;
1470
1471         if (setup_list(&symbol_conf.sym_list,
1472                        symbol_conf.sym_list_str, "symbol") < 0)
1473                 goto out_free_comm_list;
1474
1475         /*
1476          * A path to symbols of "/" is identical to ""
1477          * reset here for simplicity.
1478          */
1479         symfs = realpath(symbol_conf.symfs, NULL);
1480         if (symfs == NULL)
1481                 symfs = symbol_conf.symfs;
1482         if (strcmp(symfs, "/") == 0)
1483                 symbol_conf.symfs = "";
1484         if (symfs != symbol_conf.symfs)
1485                 free((void *)symfs);
1486
1487         symbol_conf.kptr_restrict = symbol__read_kptr_restrict();
1488
1489         symbol_conf.initialized = true;
1490         return 0;
1491
1492 out_free_comm_list:
1493         strlist__delete(symbol_conf.comm_list);
1494 out_free_dso_list:
1495         strlist__delete(symbol_conf.dso_list);
1496         return -1;
1497 }
1498
1499 void symbol__exit(void)
1500 {
1501         if (!symbol_conf.initialized)
1502                 return;
1503         strlist__delete(symbol_conf.sym_list);
1504         strlist__delete(symbol_conf.dso_list);
1505         strlist__delete(symbol_conf.comm_list);
1506         vmlinux_path__exit();
1507         symbol_conf.sym_list = symbol_conf.dso_list = symbol_conf.comm_list = NULL;
1508         symbol_conf.initialized = false;
1509 }