arch/x86/boot/compressed/relocs.c

   1 #include <stdio.h>
   2 #include <stdarg.h>
   3 #include <stdlib.h>
   4 #include <stdint.h>
   5 #include <string.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8 #include <elf.h>
   9 #include <byteswap.h>
  10 #define USE_BSD
  11 #include <endian.h>
  12
  13 #define MAX_SHDRS 100
  14 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  15 static Elf32_Ehdr ehdr;
  16 static Elf32_Shdr shdr[MAX_SHDRS];
  17 static Elf32_Sym  *symtab[MAX_SHDRS];
  18 static Elf32_Rel  *reltab[MAX_SHDRS];
  19 static char *strtab[MAX_SHDRS];
  20 static unsigned long reloc_count, reloc_idx;
  21 static unsigned long *relocs;
  22
  23 /*
  24  * Following symbols have been audited. There values are constant and do
  25  * not change if bzImage is loaded at a different physical address than
  26  * the address for which it has been compiled. Don't warn user about
  27  * absolute relocations present w.r.t these symbols.
  28  */
  29 static const char* safe_abs_relocs[] = {
  30                 "xen_irq_disable_direct_reloc",
  31                 "xen_save_fl_direct_reloc",
  32 };
  33
  34 static int is_safe_abs_reloc(const char* sym_name)
  35 {
  36         int i;
  37
  38         for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
  39                 if (!strcmp(sym_name, safe_abs_relocs[i]))
  40                         /* Match found */
  41                         return 1;
  42         }
  43         if (strncmp(sym_name, "VDSO", 4) == 0)
  44                 return 1;
  45         if (strncmp(sym_name, "__crc_", 6) == 0)
  46                 return 1;
  47         return 0;
  48 }
  49
  50 static void die(char *fmt, ...)
  51 {
  52         va_list ap;
  53         va_start(ap, fmt);
  54         vfprintf(stderr, fmt, ap);
  55         va_end(ap);
  56         exit(1);
  57 }
  58
  59 static const char *sym_type(unsigned type)
  60 {
  61         static const char *type_name[] = {
  62 #define SYM_TYPE(X) [X] = #X
  63                 SYM_TYPE(STT_NOTYPE),
  64                 SYM_TYPE(STT_OBJECT),
  65                 SYM_TYPE(STT_FUNC),
  66                 SYM_TYPE(STT_SECTION),
  67                 SYM_TYPE(STT_FILE),
  68                 SYM_TYPE(STT_COMMON),
  69                 SYM_TYPE(STT_TLS),
  70 #undef SYM_TYPE
  71         };
  72         const char *name = "unknown sym type name";
  73         if (type < ARRAY_SIZE(type_name)) {
  74                 name = type_name[type];
  75         }
  76         return name;
  77 }
  78
  79 static const char *sym_bind(unsigned bind)
  80 {
  81         static const char *bind_name[] = {
  82 #define SYM_BIND(X) [X] = #X
  83                 SYM_BIND(STB_LOCAL),
  84                 SYM_BIND(STB_GLOBAL),
  85                 SYM_BIND(STB_WEAK),
  86 #undef SYM_BIND
  87         };
  88         const char *name = "unknown sym bind name";
  89         if (bind < ARRAY_SIZE(bind_name)) {
  90                 name = bind_name[bind];
  91         }
  92         return name;
  93 }
  94
  95 static const char *sym_visibility(unsigned visibility)
  96 {
  97         static const char *visibility_name[] = {
  98 #define SYM_VISIBILITY(X) [X] = #X
  99                 SYM_VISIBILITY(STV_DEFAULT),
 100                 SYM_VISIBILITY(STV_INTERNAL),
 101                 SYM_VISIBILITY(STV_HIDDEN),
 102                 SYM_VISIBILITY(STV_PROTECTED),
 103 #undef SYM_VISIBILITY
 104         };
 105         const char *name = "unknown sym visibility name";
 106         if (visibility < ARRAY_SIZE(visibility_name)) {
 107                 name = visibility_name[visibility];
 108         }
 109         return name;
 110 }
 111
 112 static const char *rel_type(unsigned type)
 113 {
 114         static const char *type_name[] = {
 115 #define REL_TYPE(X) [X] = #X
 116                 REL_TYPE(R_386_NONE),
 117                 REL_TYPE(R_386_32),
 118                 REL_TYPE(R_386_PC32),
 119                 REL_TYPE(R_386_GOT32),
 120                 REL_TYPE(R_386_PLT32),
 121                 REL_TYPE(R_386_COPY),
 122                 REL_TYPE(R_386_GLOB_DAT),
 123                 REL_TYPE(R_386_JMP_SLOT),
 124                 REL_TYPE(R_386_RELATIVE),
 125                 REL_TYPE(R_386_GOTOFF),
 126                 REL_TYPE(R_386_GOTPC),
 127 #undef REL_TYPE
 128         };
 129         const char *name = "unknown type rel type name";
 130         if (type < ARRAY_SIZE(type_name)) {
 131                 name = type_name[type];
 132         }
 133         return name;
 134 }
 135
 136 static const char *sec_name(unsigned shndx)
 137 {
 138         const char *sec_strtab;
 139         const char *name;
 140         sec_strtab = strtab[ehdr.e_shstrndx];
 141         name = "<noname>";
 142         if (shndx < ehdr.e_shnum) {
 143                 name = sec_strtab + shdr[shndx].sh_name;
 144         }
 145         else if (shndx == SHN_ABS) {
 146                 name = "ABSOLUTE";
 147         }
 148         else if (shndx == SHN_COMMON) {
 149                 name = "COMMON";
 150         }
 151         return name;
 152 }
 153
 154 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 155 {
 156         const char *name;
 157         name = "<noname>";
 158         if (sym->st_name) {
 159                 name = sym_strtab + sym->st_name;
 160         }
 161         else {
 162                 name = sec_name(shdr[sym->st_shndx].sh_name);
 163         }
 164         return name;
 165 }
 166
 167
 168
 169 #if BYTE_ORDER == LITTLE_ENDIAN
 170 #define le16_to_cpu(val) (val)
 171 #define le32_to_cpu(val) (val)
 172 #endif
 173 #if BYTE_ORDER == BIG_ENDIAN
 174 #define le16_to_cpu(val) bswap_16(val)
 175 #define le32_to_cpu(val) bswap_32(val)
 176 #endif
 177
 178 static uint16_t elf16_to_cpu(uint16_t val)
 179 {
 180         return le16_to_cpu(val);
 181 }
 182
 183 static uint32_t elf32_to_cpu(uint32_t val)
 184 {
 185         return le32_to_cpu(val);
 186 }
 187
 188 static void read_ehdr(FILE *fp)
 189 {
 190         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 191                 die("Cannot read ELF header: %s\n",
 192                         strerror(errno));
 193         }
 194         if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
 195                 die("No ELF magic\n");
 196         }
 197         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 198                 die("Not a 32 bit executable\n");
 199         }
 200         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 201                 die("Not a LSB ELF executable\n");
 202         }
 203         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 204                 die("Unknown ELF version\n");
 205         }
 206         /* Convert the fields to native endian */
 207         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 208         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 209         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 210         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 211         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 212         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 213         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 214         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 215         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 216         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 217         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 218         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 219         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 220
 221         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 222                 die("Unsupported ELF header type\n");
 223         }
 224         if (ehdr.e_machine != EM_386) {
 225                 die("Not for x86\n");
 226         }
 227         if (ehdr.e_version != EV_CURRENT) {
 228                 die("Unknown ELF version\n");
 229         }
 230         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 231                 die("Bad Elf header size\n");
 232         }
 233         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 234                 die("Bad program header entry\n");
 235         }
 236         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 237                 die("Bad section header entry\n");
 238         }
 239         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 240                 die("String table index out of bounds\n");
 241         }
 242 }
 243
 244 static void read_shdrs(FILE *fp)
 245 {
 246         int i;
 247         if (ehdr.e_shnum > MAX_SHDRS) {
 248                 die("%d section headers supported: %d\n",
 249                         ehdr.e_shnum, MAX_SHDRS);
 250         }
 251         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 252                 die("Seek to %d failed: %s\n",
 253                         ehdr.e_shoff, strerror(errno));
 254         }
 255         if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
 256                 die("Cannot read ELF section headers: %s\n",
 257                         strerror(errno));
 258         }
 259         for(i = 0; i < ehdr.e_shnum; i++) {
 260                 shdr[i].sh_name      = elf32_to_cpu(shdr[i].sh_name);
 261                 shdr[i].sh_type      = elf32_to_cpu(shdr[i].sh_type);
 262                 shdr[i].sh_flags     = elf32_to_cpu(shdr[i].sh_flags);
 263                 shdr[i].sh_addr      = elf32_to_cpu(shdr[i].sh_addr);
 264                 shdr[i].sh_offset    = elf32_to_cpu(shdr[i].sh_offset);
 265                 shdr[i].sh_size      = elf32_to_cpu(shdr[i].sh_size);
 266                 shdr[i].sh_link      = elf32_to_cpu(shdr[i].sh_link);
 267                 shdr[i].sh_info      = elf32_to_cpu(shdr[i].sh_info);
 268                 shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
 269                 shdr[i].sh_entsize   = elf32_to_cpu(shdr[i].sh_entsize);
 270         }
 271
 272 }
 273
 274 static void read_strtabs(FILE *fp)
 275 {
 276         int i;
 277         for(i = 0; i < ehdr.e_shnum; i++) {
 278                 if (shdr[i].sh_type != SHT_STRTAB) {
 279                         continue;
 280                 }
 281                 strtab[i] = malloc(shdr[i].sh_size);
 282                 if (!strtab[i]) {
 283                         die("malloc of %d bytes for strtab failed\n",
 284                                 shdr[i].sh_size);
 285                 }
 286                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 287                         die("Seek to %d failed: %s\n",
 288                                 shdr[i].sh_offset, strerror(errno));
 289                 }
 290                 if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 291                         die("Cannot read symbol table: %s\n",
 292                                 strerror(errno));
 293                 }
 294         }
 295 }
 296
 297 static void read_symtabs(FILE *fp)
 298 {
 299         int i,j;
 300         for(i = 0; i < ehdr.e_shnum; i++) {
 301                 if (shdr[i].sh_type != SHT_SYMTAB) {
 302                         continue;
 303                 }
 304                 symtab[i] = malloc(shdr[i].sh_size);
 305                 if (!symtab[i]) {
 306                         die("malloc of %d bytes for symtab failed\n",
 307                                 shdr[i].sh_size);
 308                 }
 309                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 310                         die("Seek to %d failed: %s\n",
 311                                 shdr[i].sh_offset, strerror(errno));
 312                 }
 313                 if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 314                         die("Cannot read symbol table: %s\n",
 315                                 strerror(errno));
 316                 }
 317                 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
 318                         symtab[i][j].st_name  = elf32_to_cpu(symtab[i][j].st_name);
 319                         symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
 320                         symtab[i][j].st_size  = elf32_to_cpu(symtab[i][j].st_size);
 321                         symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
 322                 }
 323         }
 324 }
 325
 326
 327 static void read_relocs(FILE *fp)
 328 {
 329         int i,j;
 330         for(i = 0; i < ehdr.e_shnum; i++) {
 331                 if (shdr[i].sh_type != SHT_REL) {
 332                         continue;
 333                 }
 334                 reltab[i] = malloc(shdr[i].sh_size);
 335                 if (!reltab[i]) {
 336                         die("malloc of %d bytes for relocs failed\n",
 337                                 shdr[i].sh_size);
 338                 }
 339                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 340                         die("Seek to %d failed: %s\n",
 341                                 shdr[i].sh_offset, strerror(errno));
 342                 }
 343                 if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 344                         die("Cannot read symbol table: %s\n",
 345                                 strerror(errno));
 346                 }
 347                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 348                         reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
 349                         reltab[i][j].r_info   = elf32_to_cpu(reltab[i][j].r_info);
 350                 }
 351         }
 352 }
 353
 354
 355 static void print_absolute_symbols(void)
 356 {
 357         int i;
 358         printf("Absolute symbols\n");
 359         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 360         for(i = 0; i < ehdr.e_shnum; i++) {
 361                 char *sym_strtab;
 362                 Elf32_Sym *sh_symtab;
 363                 int j;
 364                 if (shdr[i].sh_type != SHT_SYMTAB) {
 365                         continue;
 366                 }
 367                 sh_symtab = symtab[i];
 368                 sym_strtab = strtab[shdr[i].sh_link];
 369                 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
 370                         Elf32_Sym *sym;
 371                         const char *name;
 372                         sym = &symtab[i][j];
 373                         name = sym_name(sym_strtab, sym);
 374                         if (sym->st_shndx != SHN_ABS) {
 375                                 continue;
 376                         }
 377                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 378                                 j, sym->st_value, sym->st_size,
 379                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 380                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 381                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 382                                 name);
 383                 }
 384         }
 385         printf("\n");
 386 }
 387
 388 static void print_absolute_relocs(void)
 389 {
 390         int i, printed = 0;
 391
 392         for(i = 0; i < ehdr.e_shnum; i++) {
 393                 char *sym_strtab;
 394                 Elf32_Sym *sh_symtab;
 395                 unsigned sec_applies, sec_symtab;
 396                 int j;
 397                 if (shdr[i].sh_type != SHT_REL) {
 398                         continue;
 399                 }
 400                 sec_symtab  = shdr[i].sh_link;
 401                 sec_applies = shdr[i].sh_info;
 402                 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
 403                         continue;
 404                 }
 405                 sh_symtab = symtab[sec_symtab];
 406                 sym_strtab = strtab[shdr[sec_symtab].sh_link];
 407                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 408                         Elf32_Rel *rel;
 409                         Elf32_Sym *sym;
 410                         const char *name;
 411                         rel = &reltab[i][j];
 412                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 413                         name = sym_name(sym_strtab, sym);
 414                         if (sym->st_shndx != SHN_ABS) {
 415                                 continue;
 416                         }
 417
 418                         /* Absolute symbols are not relocated if bzImage is
 419                          * loaded at a non-compiled address. Display a warning
 420                          * to user at compile time about the absolute
 421                          * relocations present.
 422                          *
 423                          * User need to audit the code to make sure
 424                          * some symbols which should have been section
 425                          * relative have not become absolute because of some
 426                          * linker optimization or wrong programming usage.
 427                          *
 428                          * Before warning check if this absolute symbol
 429                          * relocation is harmless.
 430                          */
 431                         if (is_safe_abs_reloc(name))
 432                                 continue;
 433
 434                         if (!printed) {
 435                                 printf("WARNING: Absolute relocations"
 436                                         " present\n");
 437                                 printf("Offset     Info     Type     Sym.Value "
 438                                         "Sym.Name\n");
 439                                 printed = 1;
 440                         }
 441
 442                         printf("%08x %08x %10s %08x  %s\n",
 443                                 rel->r_offset,
 444                                 rel->r_info,
 445                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 446                                 sym->st_value,
 447                                 name);
 448                 }
 449         }
 450
 451         if (printed)
 452                 printf("\n");
 453 }
 454
 455 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
 456 {
 457         int i;
 458         /* Walk through the relocations */
 459         for(i = 0; i < ehdr.e_shnum; i++) {
 460                 char *sym_strtab;
 461                 Elf32_Sym *sh_symtab;
 462                 unsigned sec_applies, sec_symtab;
 463                 int j;
 464                 if (shdr[i].sh_type != SHT_REL) {
 465                         continue;
 466                 }
 467                 sec_symtab  = shdr[i].sh_link;
 468                 sec_applies = shdr[i].sh_info;
 469                 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
 470                         continue;
 471                 }
 472                 sh_symtab = symtab[sec_symtab];
 473                 sym_strtab = strtab[shdr[sec_symtab].sh_link];
 474                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 475                         Elf32_Rel *rel;
 476                         Elf32_Sym *sym;
 477                         unsigned r_type;
 478                         rel = &reltab[i][j];
 479                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 480                         r_type = ELF32_R_TYPE(rel->r_info);
 481                         /* Don't visit relocations to absolute symbols */
 482                         if (sym->st_shndx == SHN_ABS) {
 483                                 continue;
 484                         }
 485                         if (r_type == R_386_PC32) {
 486                                 /* PC relative relocations don't need to be adjusted */
 487                         }
 488                         else if (r_type == R_386_32) {
 489                                 /* Visit relocations that need to be adjusted */
 490                                 visit(rel, sym);
 491                         }
 492                         else {
 493                                 die("Unsupported relocation type: %d\n", r_type);
 494                         }
 495                 }
 496         }
 497 }
 498
 499 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 500 {
 501         reloc_count += 1;
 502 }
 503
 504 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 505 {
 506         /* Remember the address that needs to be adjusted. */
 507         relocs[reloc_idx++] = rel->r_offset;
 508 }
 509
 510 static int cmp_relocs(const void *va, const void *vb)
 511 {
 512         const unsigned long *a, *b;
 513         a = va; b = vb;
 514         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 515 }
 516
 517 static void emit_relocs(int as_text)
 518 {
 519         int i;
 520         /* Count how many relocations I have and allocate space for them. */
 521         reloc_count = 0;
 522         walk_relocs(count_reloc);
 523         relocs = malloc(reloc_count * sizeof(relocs[0]));
 524         if (!relocs) {
 525                 die("malloc of %d entries for relocs failed\n",
 526                         reloc_count);
 527         }
 528         /* Collect up the relocations */
 529         reloc_idx = 0;
 530         walk_relocs(collect_reloc);
 531
 532         /* Order the relocations for more efficient processing */
 533         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 534
 535         /* Print the relocations */
 536         if (as_text) {
 537                 /* Print the relocations in a form suitable that
 538                  * gas will like.
 539                  */
 540                 printf(".section \".data.reloc\",\"a\"\n");
 541                 printf(".balign 4\n");
 542                 for(i = 0; i < reloc_count; i++) {
 543                         printf("\t .long 0x%08lx\n", relocs[i]);
 544                 }
 545                 printf("\n");
 546         }
 547         else {
 548                 unsigned char buf[4];
 549                 buf[0] = buf[1] = buf[2] = buf[3] = 0;
 550                 /* Print a stop */
 551                 printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
 552                 /* Now print each relocation */
 553                 for(i = 0; i < reloc_count; i++) {
 554                         buf[0] = (relocs[i] >>  0) & 0xff;
 555                         buf[1] = (relocs[i] >>  8) & 0xff;
 556                         buf[2] = (relocs[i] >> 16) & 0xff;
 557                         buf[3] = (relocs[i] >> 24) & 0xff;
 558                         printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
 559                 }
 560         }
 561 }
 562
 563 static void usage(void)
 564 {
 565         die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
 566 }
 567
 568 int main(int argc, char **argv)
 569 {
 570         int show_absolute_syms, show_absolute_relocs;
 571         int as_text;
 572         const char *fname;
 573         FILE *fp;
 574         int i;
 575
 576         show_absolute_syms = 0;
 577         show_absolute_relocs = 0;
 578         as_text = 0;
 579         fname = NULL;
 580         for(i = 1; i < argc; i++) {
 581                 char *arg = argv[i];
 582                 if (*arg == '-') {
 583                         if (strcmp(argv[1], "--abs-syms") == 0) {
 584                                 show_absolute_syms = 1;
 585                                 continue;
 586                         }
 587
 588                         if (strcmp(argv[1], "--abs-relocs") == 0) {
 589                                 show_absolute_relocs = 1;
 590                                 continue;
 591                         }
 592                         else if (strcmp(argv[1], "--text") == 0) {
 593                                 as_text = 1;
 594                                 continue;
 595                         }
 596                 }
 597                 else if (!fname) {
 598                         fname = arg;
 599                         continue;
 600                 }
 601                 usage();
 602         }
 603         if (!fname) {
 604                 usage();
 605         }
 606         fp = fopen(fname, "r");
 607         if (!fp) {
 608                 die("Cannot open %s: %s\n",
 609                         fname, strerror(errno));
 610         }
 611         read_ehdr(fp);
 612         read_shdrs(fp);
 613         read_strtabs(fp);
 614         read_symtabs(fp);
 615         read_relocs(fp);
 616         if (show_absolute_syms) {
 617                 print_absolute_symbols();
 618                 return 0;
 619         }
 620         if (show_absolute_relocs) {
 621                 print_absolute_relocs();
 622                 return 0;
 623         }
 624         emit_relocs(as_text);
 625         return 0;
 626 }