git.oblomov.eu Git - linux-2.6/blob - 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                 "__kernel_vsyscall",
  31                 "__kernel_rt_sigreturn",
  32                 "__kernel_sigreturn",
  33                 "SYSENTER_RETURN",
  34                 "VDSO_NOTE_MASK",
  35                 "xen_irq_disable_direct_reloc",
  36                 "xen_save_fl_direct_reloc",
  37 };
  38
  39 static int is_safe_abs_reloc(const char* sym_name)
  40 {
  41         int i, array_size;
  42
  43         array_size = sizeof(safe_abs_relocs)/sizeof(char*);
  44
  45         for(i = 0; i < array_size; i++) {
  46                 if (!strcmp(sym_name, safe_abs_relocs[i]))
  47                         /* Match found */
  48                         return 1;
  49         }
  50         if (strncmp(sym_name, "__crc_", 6) == 0)
  51                 return 1;
  52         return 0;
  53 }
  54
  55 static void die(char *fmt, ...)
  56 {
  57         va_list ap;
  58         va_start(ap, fmt);
  59         vfprintf(stderr, fmt, ap);
  60         va_end(ap);
  61         exit(1);
  62 }
  63
  64 static const char *sym_type(unsigned type)
  65 {
  66         static const char *type_name[] = {
  67 #define SYM_TYPE(X) [X] = #X
  68                 SYM_TYPE(STT_NOTYPE),
  69                 SYM_TYPE(STT_OBJECT),
  70                 SYM_TYPE(STT_FUNC),
  71                 SYM_TYPE(STT_SECTION),
  72                 SYM_TYPE(STT_FILE),
  73                 SYM_TYPE(STT_COMMON),
  74                 SYM_TYPE(STT_TLS),
  75 #undef SYM_TYPE
  76         };
  77         const char *name = "unknown sym type name";
  78         if (type < ARRAY_SIZE(type_name)) {
  79                 name = type_name[type];
  80         }
  81         return name;
  82 }
  83
  84 static const char *sym_bind(unsigned bind)
  85 {
  86         static const char *bind_name[] = {
  87 #define SYM_BIND(X) [X] = #X
  88                 SYM_BIND(STB_LOCAL),
  89                 SYM_BIND(STB_GLOBAL),
  90                 SYM_BIND(STB_WEAK),
  91 #undef SYM_BIND
  92         };
  93         const char *name = "unknown sym bind name";
  94         if (bind < ARRAY_SIZE(bind_name)) {
  95                 name = bind_name[bind];
  96         }
  97         return name;
  98 }
  99
 100 static const char *sym_visibility(unsigned visibility)
 101 {
 102         static const char *visibility_name[] = {
 103 #define SYM_VISIBILITY(X) [X] = #X
 104                 SYM_VISIBILITY(STV_DEFAULT),
 105                 SYM_VISIBILITY(STV_INTERNAL),
 106                 SYM_VISIBILITY(STV_HIDDEN),
 107                 SYM_VISIBILITY(STV_PROTECTED),
 108 #undef SYM_VISIBILITY
 109         };
 110         const char *name = "unknown sym visibility name";
 111         if (visibility < ARRAY_SIZE(visibility_name)) {
 112                 name = visibility_name[visibility];
 113         }
 114         return name;
 115 }
 116
 117 static const char *rel_type(unsigned type)
 118 {
 119         static const char *type_name[] = {
 120 #define REL_TYPE(X) [X] = #X
 121                 REL_TYPE(R_386_NONE),
 122                 REL_TYPE(R_386_32),
 123                 REL_TYPE(R_386_PC32),
 124                 REL_TYPE(R_386_GOT32),
 125                 REL_TYPE(R_386_PLT32),
 126                 REL_TYPE(R_386_COPY),
 127                 REL_TYPE(R_386_GLOB_DAT),
 128                 REL_TYPE(R_386_JMP_SLOT),
 129                 REL_TYPE(R_386_RELATIVE),
 130                 REL_TYPE(R_386_GOTOFF),
 131                 REL_TYPE(R_386_GOTPC),
 132 #undef REL_TYPE
 133         };
 134         const char *name = "unknown type rel type name";
 135         if (type < ARRAY_SIZE(type_name)) {
 136                 name = type_name[type];
 137         }
 138         return name;
 139 }
 140
 141 static const char *sec_name(unsigned shndx)
 142 {
 143         const char *sec_strtab;
 144         const char *name;
 145         sec_strtab = strtab[ehdr.e_shstrndx];
 146         name = "<noname>";
 147         if (shndx < ehdr.e_shnum) {
 148                 name = sec_strtab + shdr[shndx].sh_name;
 149         }
 150         else if (shndx == SHN_ABS) {
 151                 name = "ABSOLUTE";
 152         }
 153         else if (shndx == SHN_COMMON) {
 154                 name = "COMMON";
 155         }
 156         return name;
 157 }
 158
 159 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 160 {
 161         const char *name;
 162         name = "<noname>";
 163         if (sym->st_name) {
 164                 name = sym_strtab + sym->st_name;
 165         }
 166         else {
 167                 name = sec_name(shdr[sym->st_shndx].sh_name);
 168         }
 169         return name;
 170 }
 171
 172
 173
 174 #if BYTE_ORDER == LITTLE_ENDIAN
 175 #define le16_to_cpu(val) (val)
 176 #define le32_to_cpu(val) (val)
 177 #endif
 178 #if BYTE_ORDER == BIG_ENDIAN
 179 #define le16_to_cpu(val) bswap_16(val)
 180 #define le32_to_cpu(val) bswap_32(val)
 181 #endif
 182
 183 static uint16_t elf16_to_cpu(uint16_t val)
 184 {
 185         return le16_to_cpu(val);
 186 }
 187
 188 static uint32_t elf32_to_cpu(uint32_t val)
 189 {
 190         return le32_to_cpu(val);
 191 }
 192
 193 static void read_ehdr(FILE *fp)
 194 {
 195         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 196                 die("Cannot read ELF header: %s\n",
 197                         strerror(errno));
 198         }
 199         if (memcmp(ehdr.e_ident, ELFMAG, 4) != 0) {
 200                 die("No ELF magic\n");
 201         }
 202         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 203                 die("Not a 32 bit executable\n");
 204         }
 205         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 206                 die("Not a LSB ELF executable\n");
 207         }
 208         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 209                 die("Unknown ELF version\n");
 210         }
 211         /* Convert the fields to native endian */
 212         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 213         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 214         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 215         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 216         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 217         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 218         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 219         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 220         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 221         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 222         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 223         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 224         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 225
 226         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 227                 die("Unsupported ELF header type\n");
 228         }
 229         if (ehdr.e_machine != EM_386) {
 230                 die("Not for x86\n");
 231         }
 232         if (ehdr.e_version != EV_CURRENT) {
 233                 die("Unknown ELF version\n");
 234         }
 235         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 236                 die("Bad Elf header size\n");
 237         }
 238         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 239                 die("Bad program header entry\n");
 240         }
 241         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 242                 die("Bad section header entry\n");
 243         }
 244         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 245                 die("String table index out of bounds\n");
 246         }
 247 }
 248
 249 static void read_shdrs(FILE *fp)
 250 {
 251         int i;
 252         if (ehdr.e_shnum > MAX_SHDRS) {
 253                 die("%d section headers supported: %d\n",
 254                         ehdr.e_shnum, MAX_SHDRS);
 255         }
 256         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 257                 die("Seek to %d failed: %s\n",
 258                         ehdr.e_shoff, strerror(errno));
 259         }
 260         if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
 261                 die("Cannot read ELF section headers: %s\n",
 262                         strerror(errno));
 263         }
 264         for(i = 0; i < ehdr.e_shnum; i++) {
 265                 shdr[i].sh_name      = elf32_to_cpu(shdr[i].sh_name);
 266                 shdr[i].sh_type      = elf32_to_cpu(shdr[i].sh_type);
 267                 shdr[i].sh_flags     = elf32_to_cpu(shdr[i].sh_flags);
 268                 shdr[i].sh_addr      = elf32_to_cpu(shdr[i].sh_addr);
 269                 shdr[i].sh_offset    = elf32_to_cpu(shdr[i].sh_offset);
 270                 shdr[i].sh_size      = elf32_to_cpu(shdr[i].sh_size);
 271                 shdr[i].sh_link      = elf32_to_cpu(shdr[i].sh_link);
 272                 shdr[i].sh_info      = elf32_to_cpu(shdr[i].sh_info);
 273                 shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
 274                 shdr[i].sh_entsize   = elf32_to_cpu(shdr[i].sh_entsize);
 275         }
 276
 277 }
 278
 279 static void read_strtabs(FILE *fp)
 280 {
 281         int i;
 282         for(i = 0; i < ehdr.e_shnum; i++) {
 283                 if (shdr[i].sh_type != SHT_STRTAB) {
 284                         continue;
 285                 }
 286                 strtab[i] = malloc(shdr[i].sh_size);
 287                 if (!strtab[i]) {
 288                         die("malloc of %d bytes for strtab failed\n",
 289                                 shdr[i].sh_size);
 290                 }
 291                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 292                         die("Seek to %d failed: %s\n",
 293                                 shdr[i].sh_offset, strerror(errno));
 294                 }
 295                 if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 296                         die("Cannot read symbol table: %s\n",
 297                                 strerror(errno));
 298                 }
 299         }
 300 }
 301
 302 static void read_symtabs(FILE *fp)
 303 {
 304         int i,j;
 305         for(i = 0; i < ehdr.e_shnum; i++) {
 306                 if (shdr[i].sh_type != SHT_SYMTAB) {
 307                         continue;
 308                 }
 309                 symtab[i] = malloc(shdr[i].sh_size);
 310                 if (!symtab[i]) {
 311                         die("malloc of %d bytes for symtab failed\n",
 312                                 shdr[i].sh_size);
 313                 }
 314                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 315                         die("Seek to %d failed: %s\n",
 316                                 shdr[i].sh_offset, strerror(errno));
 317                 }
 318                 if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 319                         die("Cannot read symbol table: %s\n",
 320                                 strerror(errno));
 321                 }
 322                 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
 323                         symtab[i][j].st_name  = elf32_to_cpu(symtab[i][j].st_name);
 324                         symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
 325                         symtab[i][j].st_size  = elf32_to_cpu(symtab[i][j].st_size);
 326                         symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
 327                 }
 328         }
 329 }
 330
 331
 332 static void read_relocs(FILE *fp)
 333 {
 334         int i,j;
 335         for(i = 0; i < ehdr.e_shnum; i++) {
 336                 if (shdr[i].sh_type != SHT_REL) {
 337                         continue;
 338                 }
 339                 reltab[i] = malloc(shdr[i].sh_size);
 340                 if (!reltab[i]) {
 341                         die("malloc of %d bytes for relocs failed\n",
 342                                 shdr[i].sh_size);
 343                 }
 344                 if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
 345                         die("Seek to %d failed: %s\n",
 346                                 shdr[i].sh_offset, strerror(errno));
 347                 }
 348                 if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
 349                         die("Cannot read symbol table: %s\n",
 350                                 strerror(errno));
 351                 }
 352                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 353                         reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
 354                         reltab[i][j].r_info   = elf32_to_cpu(reltab[i][j].r_info);
 355                 }
 356         }
 357 }
 358
 359
 360 static void print_absolute_symbols(void)
 361 {
 362         int i;
 363         printf("Absolute symbols\n");
 364         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 365         for(i = 0; i < ehdr.e_shnum; i++) {
 366                 char *sym_strtab;
 367                 Elf32_Sym *sh_symtab;
 368                 int j;
 369                 if (shdr[i].sh_type != SHT_SYMTAB) {
 370                         continue;
 371                 }
 372                 sh_symtab = symtab[i];
 373                 sym_strtab = strtab[shdr[i].sh_link];
 374                 for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
 375                         Elf32_Sym *sym;
 376                         const char *name;
 377                         sym = &symtab[i][j];
 378                         name = sym_name(sym_strtab, sym);
 379                         if (sym->st_shndx != SHN_ABS) {
 380                                 continue;
 381                         }
 382                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 383                                 j, sym->st_value, sym->st_size,
 384                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 385                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 386                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 387                                 name);
 388                 }
 389         }
 390         printf("\n");
 391 }
 392
 393 static void print_absolute_relocs(void)
 394 {
 395         int i, printed = 0;
 396
 397         for(i = 0; i < ehdr.e_shnum; i++) {
 398                 char *sym_strtab;
 399                 Elf32_Sym *sh_symtab;
 400                 unsigned sec_applies, sec_symtab;
 401                 int j;
 402                 if (shdr[i].sh_type != SHT_REL) {
 403                         continue;
 404                 }
 405                 sec_symtab  = shdr[i].sh_link;
 406                 sec_applies = shdr[i].sh_info;
 407                 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
 408                         continue;
 409                 }
 410                 sh_symtab = symtab[sec_symtab];
 411                 sym_strtab = strtab[shdr[sec_symtab].sh_link];
 412                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 413                         Elf32_Rel *rel;
 414                         Elf32_Sym *sym;
 415                         const char *name;
 416                         rel = &reltab[i][j];
 417                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 418                         name = sym_name(sym_strtab, sym);
 419                         if (sym->st_shndx != SHN_ABS) {
 420                                 continue;
 421                         }
 422
 423                         /* Absolute symbols are not relocated if bzImage is
 424                          * loaded at a non-compiled address. Display a warning
 425                          * to user at compile time about the absolute
 426                          * relocations present.
 427                          *
 428                          * User need to audit the code to make sure
 429                          * some symbols which should have been section
 430                          * relative have not become absolute because of some
 431                          * linker optimization or wrong programming usage.
 432                          *
 433                          * Before warning check if this absolute symbol
 434                          * relocation is harmless.
 435                          */
 436                         if (is_safe_abs_reloc(name))
 437                                 continue;
 438
 439                         if (!printed) {
 440                                 printf("WARNING: Absolute relocations"
 441                                         " present\n");
 442                                 printf("Offset     Info     Type     Sym.Value "
 443                                         "Sym.Name\n");
 444                                 printed = 1;
 445                         }
 446
 447                         printf("%08x %08x %10s %08x  %s\n",
 448                                 rel->r_offset,
 449                                 rel->r_info,
 450                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 451                                 sym->st_value,
 452                                 name);
 453                 }
 454         }
 455
 456         if (printed)
 457                 printf("\n");
 458 }
 459
 460 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
 461 {
 462         int i;
 463         /* Walk through the relocations */
 464         for(i = 0; i < ehdr.e_shnum; i++) {
 465                 char *sym_strtab;
 466                 Elf32_Sym *sh_symtab;
 467                 unsigned sec_applies, sec_symtab;
 468                 int j;
 469                 if (shdr[i].sh_type != SHT_REL) {
 470                         continue;
 471                 }
 472                 sec_symtab  = shdr[i].sh_link;
 473                 sec_applies = shdr[i].sh_info;
 474                 if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
 475                         continue;
 476                 }
 477                 sh_symtab = symtab[sec_symtab];
 478                 sym_strtab = strtab[shdr[sec_symtab].sh_link];
 479                 for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
 480                         Elf32_Rel *rel;
 481                         Elf32_Sym *sym;
 482                         unsigned r_type;
 483                         rel = &reltab[i][j];
 484                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 485                         r_type = ELF32_R_TYPE(rel->r_info);
 486                         /* Don't visit relocations to absolute symbols */
 487                         if (sym->st_shndx == SHN_ABS) {
 488                                 continue;
 489                         }
 490                         if (r_type == R_386_PC32) {
 491                                 /* PC relative relocations don't need to be adjusted */
 492                         }
 493                         else if (r_type == R_386_32) {
 494                                 /* Visit relocations that need to be adjusted */
 495                                 visit(rel, sym);
 496                         }
 497                         else {
 498                                 die("Unsupported relocation type: %d\n", r_type);
 499                         }
 500                 }
 501         }
 502 }
 503
 504 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 505 {
 506         reloc_count += 1;
 507 }
 508
 509 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 510 {
 511         /* Remember the address that needs to be adjusted. */
 512         relocs[reloc_idx++] = rel->r_offset;
 513 }
 514
 515 static int cmp_relocs(const void *va, const void *vb)
 516 {
 517         const unsigned long *a, *b;
 518         a = va; b = vb;
 519         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 520 }
 521
 522 static void emit_relocs(int as_text)
 523 {
 524         int i;
 525         /* Count how many relocations I have and allocate space for them. */
 526         reloc_count = 0;
 527         walk_relocs(count_reloc);
 528         relocs = malloc(reloc_count * sizeof(relocs[0]));
 529         if (!relocs) {
 530                 die("malloc of %d entries for relocs failed\n",
 531                         reloc_count);
 532         }
 533         /* Collect up the relocations */
 534         reloc_idx = 0;
 535         walk_relocs(collect_reloc);
 536
 537         /* Order the relocations for more efficient processing */
 538         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 539
 540         /* Print the relocations */
 541         if (as_text) {
 542                 /* Print the relocations in a form suitable that
 543                  * gas will like.
 544                  */
 545                 printf(".section \".data.reloc\",\"a\"\n");
 546                 printf(".balign 4\n");
 547                 for(i = 0; i < reloc_count; i++) {
 548                         printf("\t .long 0x%08lx\n", relocs[i]);
 549                 }
 550                 printf("\n");
 551         }
 552         else {
 553                 unsigned char buf[4];
 554                 buf[0] = buf[1] = buf[2] = buf[3] = 0;
 555                 /* Print a stop */
 556                 printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
 557                 /* Now print each relocation */
 558                 for(i = 0; i < reloc_count; i++) {
 559                         buf[0] = (relocs[i] >>  0) & 0xff;
 560                         buf[1] = (relocs[i] >>  8) & 0xff;
 561                         buf[2] = (relocs[i] >> 16) & 0xff;
 562                         buf[3] = (relocs[i] >> 24) & 0xff;
 563                         printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
 564                 }
 565         }
 566 }
 567
 568 static void usage(void)
 569 {
 570         die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
 571 }
 572
 573 int main(int argc, char **argv)
 574 {
 575         int show_absolute_syms, show_absolute_relocs;
 576         int as_text;
 577         const char *fname;
 578         FILE *fp;
 579         int i;
 580
 581         show_absolute_syms = 0;
 582         show_absolute_relocs = 0;
 583         as_text = 0;
 584         fname = NULL;
 585         for(i = 1; i < argc; i++) {
 586                 char *arg = argv[i];
 587                 if (*arg == '-') {
 588                         if (strcmp(argv[1], "--abs-syms") == 0) {
 589                                 show_absolute_syms = 1;
 590                                 continue;
 591                         }
 592
 593                         if (strcmp(argv[1], "--abs-relocs") == 0) {
 594                                 show_absolute_relocs = 1;
 595                                 continue;
 596                         }
 597                         else if (strcmp(argv[1], "--text") == 0) {
 598                                 as_text = 1;
 599                                 continue;
 600                         }
 601                 }
 602                 else if (!fname) {
 603                         fname = arg;
 604                         continue;
 605                 }
 606                 usage();
 607         }
 608         if (!fname) {
 609                 usage();
 610         }
 611         fp = fopen(fname, "r");
 612         if (!fp) {
 613                 die("Cannot open %s: %s\n",
 614                         fname, strerror(errno));
 615         }
 616         read_ehdr(fp);
 617         read_shdrs(fp);
 618         read_strtabs(fp);
 619         read_symtabs(fp);
 620         read_relocs(fp);
 621         if (show_absolute_syms) {
 622                 print_absolute_symbols();
 623                 return 0;
 624         }
 625         if (show_absolute_relocs) {
 626                 print_absolute_relocs();
 627                 return 0;
 628         }
 629         emit_relocs(as_text);
 630         return 0;
 631 }