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 #include <regex.h>
  13 #include <tools/le_byteshift.h>
  14
  15 static void die(char *fmt, ...);
  16
  17 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  18 static Elf32_Ehdr ehdr;
  19 static unsigned long reloc_count, reloc_idx;
  20 static unsigned long *relocs;
  21
  22 struct section {
  23         Elf32_Shdr     shdr;
  24         struct section *link;
  25         Elf32_Sym      *symtab;
  26         Elf32_Rel      *reltab;
  27         char           *strtab;
  28 };
  29 static struct section *secs;
  30
  31 /*
  32  * Following symbols have been audited. There values are constant and do
  33  * not change if bzImage is loaded at a different physical address than
  34  * the address for which it has been compiled. Don't warn user about
  35  * absolute relocations present w.r.t these symbols.
  36  */
  37 static const char abs_sym_regex[] =
  38         "^(xen_irq_disable_direct_reloc$|"
  39         "xen_save_fl_direct_reloc$|"
  40         "VDSO|"
  41         "__crc_)";
  42 static regex_t abs_sym_regex_c;
  43 static int is_abs_reloc(const char *sym_name)
  44 {
  45         return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0);
  46 }
  47
  48 /*
  49  * These symbols are known to be relative, even if the linker marks them
  50  * as absolute (typically defined outside any section in the linker script.)
  51  */
  52 static const char rel_sym_regex[] =
  53         "^_end$";
  54 static regex_t rel_sym_regex_c;
  55 static int is_rel_reloc(const char *sym_name)
  56 {
  57         return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0);
  58 }
  59
  60 static void regex_init(void)
  61 {
  62         char errbuf[128];
  63         int err;
  64
  65         err = regcomp(&abs_sym_regex_c, abs_sym_regex,
  66                       REG_EXTENDED|REG_NOSUB);
  67         if (err) {
  68                 regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf);
  69                 die("%s", errbuf);
  70         }
  71
  72         err = regcomp(&rel_sym_regex_c, rel_sym_regex,
  73                       REG_EXTENDED|REG_NOSUB);
  74         if (err) {
  75                 regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf);
  76                 die("%s", errbuf);
  77         }
  78 }
  79
  80 static void die(char *fmt, ...)
  81 {
  82         va_list ap;
  83         va_start(ap, fmt);
  84         vfprintf(stderr, fmt, ap);
  85         va_end(ap);
  86         exit(1);
  87 }
  88
  89 static const char *sym_type(unsigned type)
  90 {
  91         static const char *type_name[] = {
  92 #define SYM_TYPE(X) [X] = #X
  93                 SYM_TYPE(STT_NOTYPE),
  94                 SYM_TYPE(STT_OBJECT),
  95                 SYM_TYPE(STT_FUNC),
  96                 SYM_TYPE(STT_SECTION),
  97                 SYM_TYPE(STT_FILE),
  98                 SYM_TYPE(STT_COMMON),
  99                 SYM_TYPE(STT_TLS),
 100 #undef SYM_TYPE
 101         };
 102         const char *name = "unknown sym type name";
 103         if (type < ARRAY_SIZE(type_name)) {
 104                 name = type_name[type];
 105         }
 106         return name;
 107 }
 108
 109 static const char *sym_bind(unsigned bind)
 110 {
 111         static const char *bind_name[] = {
 112 #define SYM_BIND(X) [X] = #X
 113                 SYM_BIND(STB_LOCAL),
 114                 SYM_BIND(STB_GLOBAL),
 115                 SYM_BIND(STB_WEAK),
 116 #undef SYM_BIND
 117         };
 118         const char *name = "unknown sym bind name";
 119         if (bind < ARRAY_SIZE(bind_name)) {
 120                 name = bind_name[bind];
 121         }
 122         return name;
 123 }
 124
 125 static const char *sym_visibility(unsigned visibility)
 126 {
 127         static const char *visibility_name[] = {
 128 #define SYM_VISIBILITY(X) [X] = #X
 129                 SYM_VISIBILITY(STV_DEFAULT),
 130                 SYM_VISIBILITY(STV_INTERNAL),
 131                 SYM_VISIBILITY(STV_HIDDEN),
 132                 SYM_VISIBILITY(STV_PROTECTED),
 133 #undef SYM_VISIBILITY
 134         };
 135         const char *name = "unknown sym visibility name";
 136         if (visibility < ARRAY_SIZE(visibility_name)) {
 137                 name = visibility_name[visibility];
 138         }
 139         return name;
 140 }
 141
 142 static const char *rel_type(unsigned type)
 143 {
 144         static const char *type_name[] = {
 145 #define REL_TYPE(X) [X] = #X
 146                 REL_TYPE(R_386_NONE),
 147                 REL_TYPE(R_386_32),
 148                 REL_TYPE(R_386_PC32),
 149                 REL_TYPE(R_386_GOT32),
 150                 REL_TYPE(R_386_PLT32),
 151                 REL_TYPE(R_386_COPY),
 152                 REL_TYPE(R_386_GLOB_DAT),
 153                 REL_TYPE(R_386_JMP_SLOT),
 154                 REL_TYPE(R_386_RELATIVE),
 155                 REL_TYPE(R_386_GOTOFF),
 156                 REL_TYPE(R_386_GOTPC),
 157 #undef REL_TYPE
 158         };
 159         const char *name = "unknown type rel type name";
 160         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 161                 name = type_name[type];
 162         }
 163         return name;
 164 }
 165
 166 static const char *sec_name(unsigned shndx)
 167 {
 168         const char *sec_strtab;
 169         const char *name;
 170         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 171         name = "<noname>";
 172         if (shndx < ehdr.e_shnum) {
 173                 name = sec_strtab + secs[shndx].shdr.sh_name;
 174         }
 175         else if (shndx == SHN_ABS) {
 176                 name = "ABSOLUTE";
 177         }
 178         else if (shndx == SHN_COMMON) {
 179                 name = "COMMON";
 180         }
 181         return name;
 182 }
 183
 184 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 185 {
 186         const char *name;
 187         name = "<noname>";
 188         if (sym->st_name) {
 189                 name = sym_strtab + sym->st_name;
 190         }
 191         else {
 192                 name = sec_name(secs[sym->st_shndx].shdr.sh_name);
 193         }
 194         return name;
 195 }
 196
 197
 198
 199 #if BYTE_ORDER == LITTLE_ENDIAN
 200 #define le16_to_cpu(val) (val)
 201 #define le32_to_cpu(val) (val)
 202 #endif
 203 #if BYTE_ORDER == BIG_ENDIAN
 204 #define le16_to_cpu(val) bswap_16(val)
 205 #define le32_to_cpu(val) bswap_32(val)
 206 #endif
 207
 208 static uint16_t elf16_to_cpu(uint16_t val)
 209 {
 210         return le16_to_cpu(val);
 211 }
 212
 213 static uint32_t elf32_to_cpu(uint32_t val)
 214 {
 215         return le32_to_cpu(val);
 216 }
 217
 218 static void read_ehdr(FILE *fp)
 219 {
 220         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 221                 die("Cannot read ELF header: %s\n",
 222                         strerror(errno));
 223         }
 224         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 225                 die("No ELF magic\n");
 226         }
 227         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 228                 die("Not a 32 bit executable\n");
 229         }
 230         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 231                 die("Not a LSB ELF executable\n");
 232         }
 233         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 234                 die("Unknown ELF version\n");
 235         }
 236         /* Convert the fields to native endian */
 237         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 238         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 239         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 240         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 241         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 242         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 243         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 244         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 245         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 246         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 247         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 248         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 249         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 250
 251         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 252                 die("Unsupported ELF header type\n");
 253         }
 254         if (ehdr.e_machine != EM_386) {
 255                 die("Not for x86\n");
 256         }
 257         if (ehdr.e_version != EV_CURRENT) {
 258                 die("Unknown ELF version\n");
 259         }
 260         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 261                 die("Bad Elf header size\n");
 262         }
 263         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 264                 die("Bad program header entry\n");
 265         }
 266         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 267                 die("Bad section header entry\n");
 268         }
 269         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 270                 die("String table index out of bounds\n");
 271         }
 272 }
 273
 274 static void read_shdrs(FILE *fp)
 275 {
 276         int i;
 277         Elf32_Shdr shdr;
 278
 279         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 280         if (!secs) {
 281                 die("Unable to allocate %d section headers\n",
 282                     ehdr.e_shnum);
 283         }
 284         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 285                 die("Seek to %d failed: %s\n",
 286                         ehdr.e_shoff, strerror(errno));
 287         }
 288         for (i = 0; i < ehdr.e_shnum; i++) {
 289                 struct section *sec = &secs[i];
 290                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 291                         die("Cannot read ELF section headers %d/%d: %s\n",
 292                             i, ehdr.e_shnum, strerror(errno));
 293                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 294                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 295                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 296                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 297                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 298                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 299                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 300                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 301                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 302                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 303                 if (sec->shdr.sh_link < ehdr.e_shnum)
 304                         sec->link = &secs[sec->shdr.sh_link];
 305         }
 306
 307 }
 308
 309 static void read_strtabs(FILE *fp)
 310 {
 311         int i;
 312         for (i = 0; i < ehdr.e_shnum; i++) {
 313                 struct section *sec = &secs[i];
 314                 if (sec->shdr.sh_type != SHT_STRTAB) {
 315                         continue;
 316                 }
 317                 sec->strtab = malloc(sec->shdr.sh_size);
 318                 if (!sec->strtab) {
 319                         die("malloc of %d bytes for strtab failed\n",
 320                                 sec->shdr.sh_size);
 321                 }
 322                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 323                         die("Seek to %d failed: %s\n",
 324                                 sec->shdr.sh_offset, strerror(errno));
 325                 }
 326                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 327                     != sec->shdr.sh_size) {
 328                         die("Cannot read symbol table: %s\n",
 329                                 strerror(errno));
 330                 }
 331         }
 332 }
 333
 334 static void read_symtabs(FILE *fp)
 335 {
 336         int i,j;
 337         for (i = 0; i < ehdr.e_shnum; i++) {
 338                 struct section *sec = &secs[i];
 339                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 340                         continue;
 341                 }
 342                 sec->symtab = malloc(sec->shdr.sh_size);
 343                 if (!sec->symtab) {
 344                         die("malloc of %d bytes for symtab failed\n",
 345                                 sec->shdr.sh_size);
 346                 }
 347                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 348                         die("Seek to %d failed: %s\n",
 349                                 sec->shdr.sh_offset, strerror(errno));
 350                 }
 351                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 352                     != sec->shdr.sh_size) {
 353                         die("Cannot read symbol table: %s\n",
 354                                 strerror(errno));
 355                 }
 356                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 357                         Elf32_Sym *sym = &sec->symtab[j];
 358                         sym->st_name  = elf32_to_cpu(sym->st_name);
 359                         sym->st_value = elf32_to_cpu(sym->st_value);
 360                         sym->st_size  = elf32_to_cpu(sym->st_size);
 361                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 362                 }
 363         }
 364 }
 365
 366
 367 static void read_relocs(FILE *fp)
 368 {
 369         int i,j;
 370         for (i = 0; i < ehdr.e_shnum; i++) {
 371                 struct section *sec = &secs[i];
 372                 if (sec->shdr.sh_type != SHT_REL) {
 373                         continue;
 374                 }
 375                 sec->reltab = malloc(sec->shdr.sh_size);
 376                 if (!sec->reltab) {
 377                         die("malloc of %d bytes for relocs failed\n",
 378                                 sec->shdr.sh_size);
 379                 }
 380                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 381                         die("Seek to %d failed: %s\n",
 382                                 sec->shdr.sh_offset, strerror(errno));
 383                 }
 384                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 385                     != sec->shdr.sh_size) {
 386                         die("Cannot read symbol table: %s\n",
 387                                 strerror(errno));
 388                 }
 389                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 390                         Elf32_Rel *rel = &sec->reltab[j];
 391                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 392                         rel->r_info   = elf32_to_cpu(rel->r_info);
 393                 }
 394         }
 395 }
 396
 397
 398 static void print_absolute_symbols(void)
 399 {
 400         int i;
 401         printf("Absolute symbols\n");
 402         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 403         for (i = 0; i < ehdr.e_shnum; i++) {
 404                 struct section *sec = &secs[i];
 405                 char *sym_strtab;
 406                 Elf32_Sym *sh_symtab;
 407                 int j;
 408
 409                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 410                         continue;
 411                 }
 412                 sh_symtab = sec->symtab;
 413                 sym_strtab = sec->link->strtab;
 414                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 415                         Elf32_Sym *sym;
 416                         const char *name;
 417                         sym = &sec->symtab[j];
 418                         name = sym_name(sym_strtab, sym);
 419                         if (sym->st_shndx != SHN_ABS) {
 420                                 continue;
 421                         }
 422                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 423                                 j, sym->st_value, sym->st_size,
 424                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 425                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 426                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 427                                 name);
 428                 }
 429         }
 430         printf("\n");
 431 }
 432
 433 static void print_absolute_relocs(void)
 434 {
 435         int i, printed = 0;
 436
 437         for (i = 0; i < ehdr.e_shnum; i++) {
 438                 struct section *sec = &secs[i];
 439                 struct section *sec_applies, *sec_symtab;
 440                 char *sym_strtab;
 441                 Elf32_Sym *sh_symtab;
 442                 int j;
 443                 if (sec->shdr.sh_type != SHT_REL) {
 444                         continue;
 445                 }
 446                 sec_symtab  = sec->link;
 447                 sec_applies = &secs[sec->shdr.sh_info];
 448                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 449                         continue;
 450                 }
 451                 sh_symtab  = sec_symtab->symtab;
 452                 sym_strtab = sec_symtab->link->strtab;
 453                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 454                         Elf32_Rel *rel;
 455                         Elf32_Sym *sym;
 456                         const char *name;
 457                         rel = &sec->reltab[j];
 458                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 459                         name = sym_name(sym_strtab, sym);
 460                         if (sym->st_shndx != SHN_ABS) {
 461                                 continue;
 462                         }
 463
 464                         /* Absolute symbols are not relocated if bzImage is
 465                          * loaded at a non-compiled address. Display a warning
 466                          * to user at compile time about the absolute
 467                          * relocations present.
 468                          *
 469                          * User need to audit the code to make sure
 470                          * some symbols which should have been section
 471                          * relative have not become absolute because of some
 472                          * linker optimization or wrong programming usage.
 473                          *
 474                          * Before warning check if this absolute symbol
 475                          * relocation is harmless.
 476                          */
 477                         if (is_abs_reloc(name) || is_rel_reloc(name))
 478                                 continue;
 479
 480                         if (!printed) {
 481                                 printf("WARNING: Absolute relocations"
 482                                         " present\n");
 483                                 printf("Offset     Info     Type     Sym.Value "
 484                                         "Sym.Name\n");
 485                                 printed = 1;
 486                         }
 487
 488                         printf("%08x %08x %10s %08x  %s\n",
 489                                 rel->r_offset,
 490                                 rel->r_info,
 491                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 492                                 sym->st_value,
 493                                 name);
 494                 }
 495         }
 496
 497         if (printed)
 498                 printf("\n");
 499 }
 500
 501 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
 502 {
 503         int i;
 504         /* Walk through the relocations */
 505         for (i = 0; i < ehdr.e_shnum; i++) {
 506                 char *sym_strtab;
 507                 Elf32_Sym *sh_symtab;
 508                 struct section *sec_applies, *sec_symtab;
 509                 int j;
 510                 struct section *sec = &secs[i];
 511
 512                 if (sec->shdr.sh_type != SHT_REL) {
 513                         continue;
 514                 }
 515                 sec_symtab  = sec->link;
 516                 sec_applies = &secs[sec->shdr.sh_info];
 517                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 518                         continue;
 519                 }
 520                 sh_symtab = sec_symtab->symtab;
 521                 sym_strtab = sec_symtab->link->strtab;
 522                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 523                         Elf32_Rel *rel;
 524                         Elf32_Sym *sym;
 525                         unsigned r_type;
 526                         rel = &sec->reltab[j];
 527                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 528                         r_type = ELF32_R_TYPE(rel->r_info);
 529                         /* Don't visit relocations to absolute symbols */
 530                         if (sym->st_shndx == SHN_ABS &&
 531                             !is_rel_reloc(sym_name(sym_strtab, sym))) {
 532                                 continue;
 533                         }
 534                         switch (r_type) {
 535                         case R_386_NONE:
 536                         case R_386_PC32:
 537                                 /*
 538                                  * NONE can be ignored and and PC relative
 539                                  * relocations don't need to be adjusted.
 540                                  */
 541                                 break;
 542                         case R_386_32:
 543                                 /* Visit relocations that need to be adjusted */
 544                                 visit(rel, sym);
 545                                 break;
 546                         default:
 547                                 die("Unsupported relocation type: %s (%d)\n",
 548                                     rel_type(r_type), r_type);
 549                                 break;
 550                         }
 551                 }
 552         }
 553 }
 554
 555 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 556 {
 557         reloc_count += 1;
 558 }
 559
 560 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 561 {
 562         /* Remember the address that needs to be adjusted. */
 563         relocs[reloc_idx++] = rel->r_offset;
 564 }
 565
 566 static int cmp_relocs(const void *va, const void *vb)
 567 {
 568         const unsigned long *a, *b;
 569         a = va; b = vb;
 570         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 571 }
 572
 573 static void emit_relocs(int as_text)
 574 {
 575         int i;
 576         /* Count how many relocations I have and allocate space for them. */
 577         reloc_count = 0;
 578         walk_relocs(count_reloc);
 579         relocs = malloc(reloc_count * sizeof(relocs[0]));
 580         if (!relocs) {
 581                 die("malloc of %d entries for relocs failed\n",
 582                         reloc_count);
 583         }
 584         /* Collect up the relocations */
 585         reloc_idx = 0;
 586         walk_relocs(collect_reloc);
 587
 588         /* Order the relocations for more efficient processing */
 589         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 590
 591         /* Print the relocations */
 592         if (as_text) {
 593                 /* Print the relocations in a form suitable that
 594                  * gas will like.
 595                  */
 596                 printf(".section \".data.reloc\",\"a\"\n");
 597                 printf(".balign 4\n");
 598                 for (i = 0; i < reloc_count; i++) {
 599                         printf("\t .long 0x%08lx\n", relocs[i]);
 600                 }
 601                 printf("\n");
 602         }
 603         else {
 604                 unsigned char buf[4];
 605                 /* Print a stop */
 606                 fwrite("\0\0\0\0", 4, 1, stdout);
 607                 /* Now print each relocation */
 608                 for (i = 0; i < reloc_count; i++) {
 609                         put_unaligned_le32(relocs[i], buf);
 610                         fwrite(buf, 4, 1, stdout);
 611                 }
 612         }
 613 }
 614
 615 static void usage(void)
 616 {
 617         die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
 618 }
 619
 620 int main(int argc, char **argv)
 621 {
 622         int show_absolute_syms, show_absolute_relocs;
 623         int as_text;
 624         const char *fname;
 625         FILE *fp;
 626         int i;
 627
 628         regex_init();
 629
 630         show_absolute_syms = 0;
 631         show_absolute_relocs = 0;
 632         as_text = 0;
 633         fname = NULL;
 634         for (i = 1; i < argc; i++) {
 635                 char *arg = argv[i];
 636                 if (*arg == '-') {
 637                         if (strcmp(argv[1], "--abs-syms") == 0) {
 638                                 show_absolute_syms = 1;
 639                                 continue;
 640                         }
 641
 642                         if (strcmp(argv[1], "--abs-relocs") == 0) {
 643                                 show_absolute_relocs = 1;
 644                                 continue;
 645                         }
 646                         else if (strcmp(argv[1], "--text") == 0) {
 647                                 as_text = 1;
 648                                 continue;
 649                         }
 650                 }
 651                 else if (!fname) {
 652                         fname = arg;
 653                         continue;
 654                 }
 655                 usage();
 656         }
 657         if (!fname) {
 658                 usage();
 659         }
 660         fp = fopen(fname, "r");
 661         if (!fp) {
 662                 die("Cannot open %s: %s\n",
 663                         fname, strerror(errno));
 664         }
 665         read_ehdr(fp);
 666         read_shdrs(fp);
 667         read_strtabs(fp);
 668         read_symtabs(fp);
 669         read_relocs(fp);
 670         if (show_absolute_syms) {
 671                 print_absolute_symbols();
 672                 return 0;
 673         }
 674         if (show_absolute_relocs) {
 675                 print_absolute_relocs();
 676                 return 0;
 677         }
 678         emit_relocs(as_text);
 679         return 0;
 680 }