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
  14 static void die(char *fmt, ...);
  15
  16 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  17 static Elf32_Ehdr ehdr;
  18 static unsigned long reloc_count, reloc_idx;
  19 static unsigned long *relocs;
  20
  21 struct section {
  22         Elf32_Shdr     shdr;
  23         struct section *link;
  24         Elf32_Sym      *symtab;
  25         Elf32_Rel      *reltab;
  26         char           *strtab;
  27 };
  28 static struct section *secs;
  29
  30 /*
  31  * Following symbols have been audited. There values are constant and do
  32  * not change if bzImage is loaded at a different physical address than
  33  * the address for which it has been compiled. Don't warn user about
  34  * absolute relocations present w.r.t these symbols.
  35  */
  36 static const char abs_sym_regex[] =
  37         "^(xen_irq_disable_direct_reloc$|"
  38         "xen_save_fl_direct_reloc$|"
  39         "VDSO|"
  40         "__crc_)";
  41 static regex_t abs_sym_regex_c;
  42 static int is_abs_reloc(const char *sym_name)
  43 {
  44         return !regexec(&abs_sym_regex_c, sym_name, 0, NULL, 0);
  45 }
  46
  47 /*
  48  * These symbols are known to be relative, even if the linker marks them
  49  * as absolute (typically defined outside any section in the linker script.)
  50  */
  51 static const char rel_sym_regex[] =
  52         "^_end$";
  53 static regex_t rel_sym_regex_c;
  54 static int is_rel_reloc(const char *sym_name)
  55 {
  56         return !regexec(&rel_sym_regex_c, sym_name, 0, NULL, 0);
  57 }
  58
  59 static void regex_init(void)
  60 {
  61         char errbuf[128];
  62         int err;
  63
  64         err = regcomp(&abs_sym_regex_c, abs_sym_regex,
  65                       REG_EXTENDED|REG_NOSUB);
  66         if (err) {
  67                 regerror(err, &abs_sym_regex_c, errbuf, sizeof errbuf);
  68                 die("%s", errbuf);
  69         }
  70
  71         err = regcomp(&rel_sym_regex_c, rel_sym_regex,
  72                       REG_EXTENDED|REG_NOSUB);
  73         if (err) {
  74                 regerror(err, &rel_sym_regex_c, errbuf, sizeof errbuf);
  75                 die("%s", errbuf);
  76         }
  77 }
  78
  79 static void die(char *fmt, ...)
  80 {
  81         va_list ap;
  82         va_start(ap, fmt);
  83         vfprintf(stderr, fmt, ap);
  84         va_end(ap);
  85         exit(1);
  86 }
  87
  88 static const char *sym_type(unsigned type)
  89 {
  90         static const char *type_name[] = {
  91 #define SYM_TYPE(X) [X] = #X
  92                 SYM_TYPE(STT_NOTYPE),
  93                 SYM_TYPE(STT_OBJECT),
  94                 SYM_TYPE(STT_FUNC),
  95                 SYM_TYPE(STT_SECTION),
  96                 SYM_TYPE(STT_FILE),
  97                 SYM_TYPE(STT_COMMON),
  98                 SYM_TYPE(STT_TLS),
  99 #undef SYM_TYPE
 100         };
 101         const char *name = "unknown sym type name";
 102         if (type < ARRAY_SIZE(type_name)) {
 103                 name = type_name[type];
 104         }
 105         return name;
 106 }
 107
 108 static const char *sym_bind(unsigned bind)
 109 {
 110         static const char *bind_name[] = {
 111 #define SYM_BIND(X) [X] = #X
 112                 SYM_BIND(STB_LOCAL),
 113                 SYM_BIND(STB_GLOBAL),
 114                 SYM_BIND(STB_WEAK),
 115 #undef SYM_BIND
 116         };
 117         const char *name = "unknown sym bind name";
 118         if (bind < ARRAY_SIZE(bind_name)) {
 119                 name = bind_name[bind];
 120         }
 121         return name;
 122 }
 123
 124 static const char *sym_visibility(unsigned visibility)
 125 {
 126         static const char *visibility_name[] = {
 127 #define SYM_VISIBILITY(X) [X] = #X
 128                 SYM_VISIBILITY(STV_DEFAULT),
 129                 SYM_VISIBILITY(STV_INTERNAL),
 130                 SYM_VISIBILITY(STV_HIDDEN),
 131                 SYM_VISIBILITY(STV_PROTECTED),
 132 #undef SYM_VISIBILITY
 133         };
 134         const char *name = "unknown sym visibility name";
 135         if (visibility < ARRAY_SIZE(visibility_name)) {
 136                 name = visibility_name[visibility];
 137         }
 138         return name;
 139 }
 140
 141 static const char *rel_type(unsigned type)
 142 {
 143         static const char *type_name[] = {
 144 #define REL_TYPE(X) [X] = #X
 145                 REL_TYPE(R_386_NONE),
 146                 REL_TYPE(R_386_32),
 147                 REL_TYPE(R_386_PC32),
 148                 REL_TYPE(R_386_GOT32),
 149                 REL_TYPE(R_386_PLT32),
 150                 REL_TYPE(R_386_COPY),
 151                 REL_TYPE(R_386_GLOB_DAT),
 152                 REL_TYPE(R_386_JMP_SLOT),
 153                 REL_TYPE(R_386_RELATIVE),
 154                 REL_TYPE(R_386_GOTOFF),
 155                 REL_TYPE(R_386_GOTPC),
 156 #undef REL_TYPE
 157         };
 158         const char *name = "unknown type rel type name";
 159         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 160                 name = type_name[type];
 161         }
 162         return name;
 163 }
 164
 165 static const char *sec_name(unsigned shndx)
 166 {
 167         const char *sec_strtab;
 168         const char *name;
 169         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 170         name = "<noname>";
 171         if (shndx < ehdr.e_shnum) {
 172                 name = sec_strtab + secs[shndx].shdr.sh_name;
 173         }
 174         else if (shndx == SHN_ABS) {
 175                 name = "ABSOLUTE";
 176         }
 177         else if (shndx == SHN_COMMON) {
 178                 name = "COMMON";
 179         }
 180         return name;
 181 }
 182
 183 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 184 {
 185         const char *name;
 186         name = "<noname>";
 187         if (sym->st_name) {
 188                 name = sym_strtab + sym->st_name;
 189         }
 190         else {
 191                 name = sec_name(secs[sym->st_shndx].shdr.sh_name);
 192         }
 193         return name;
 194 }
 195
 196
 197
 198 #if BYTE_ORDER == LITTLE_ENDIAN
 199 #define le16_to_cpu(val) (val)
 200 #define le32_to_cpu(val) (val)
 201 #endif
 202 #if BYTE_ORDER == BIG_ENDIAN
 203 #define le16_to_cpu(val) bswap_16(val)
 204 #define le32_to_cpu(val) bswap_32(val)
 205 #endif
 206
 207 static uint16_t elf16_to_cpu(uint16_t val)
 208 {
 209         return le16_to_cpu(val);
 210 }
 211
 212 static uint32_t elf32_to_cpu(uint32_t val)
 213 {
 214         return le32_to_cpu(val);
 215 }
 216
 217 static void read_ehdr(FILE *fp)
 218 {
 219         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 220                 die("Cannot read ELF header: %s\n",
 221                         strerror(errno));
 222         }
 223         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 224                 die("No ELF magic\n");
 225         }
 226         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 227                 die("Not a 32 bit executable\n");
 228         }
 229         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 230                 die("Not a LSB ELF executable\n");
 231         }
 232         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 233                 die("Unknown ELF version\n");
 234         }
 235         /* Convert the fields to native endian */
 236         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 237         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 238         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 239         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 240         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 241         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 242         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 243         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 244         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 245         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 246         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 247         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 248         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 249
 250         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 251                 die("Unsupported ELF header type\n");
 252         }
 253         if (ehdr.e_machine != EM_386) {
 254                 die("Not for x86\n");
 255         }
 256         if (ehdr.e_version != EV_CURRENT) {
 257                 die("Unknown ELF version\n");
 258         }
 259         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 260                 die("Bad Elf header size\n");
 261         }
 262         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 263                 die("Bad program header entry\n");
 264         }
 265         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 266                 die("Bad section header entry\n");
 267         }
 268         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 269                 die("String table index out of bounds\n");
 270         }
 271 }
 272
 273 static void read_shdrs(FILE *fp)
 274 {
 275         int i;
 276         Elf32_Shdr shdr;
 277
 278         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 279         if (!secs) {
 280                 die("Unable to allocate %d section headers\n",
 281                     ehdr.e_shnum);
 282         }
 283         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 284                 die("Seek to %d failed: %s\n",
 285                         ehdr.e_shoff, strerror(errno));
 286         }
 287         for (i = 0; i < ehdr.e_shnum; i++) {
 288                 struct section *sec = &secs[i];
 289                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 290                         die("Cannot read ELF section headers %d/%d: %s\n",
 291                             i, ehdr.e_shnum, strerror(errno));
 292                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 293                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 294                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 295                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 296                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 297                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 298                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 299                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 300                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 301                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 302                 if (sec->shdr.sh_link < ehdr.e_shnum)
 303                         sec->link = &secs[sec->shdr.sh_link];
 304         }
 305
 306 }
 307
 308 static void read_strtabs(FILE *fp)
 309 {
 310         int i;
 311         for (i = 0; i < ehdr.e_shnum; i++) {
 312                 struct section *sec = &secs[i];
 313                 if (sec->shdr.sh_type != SHT_STRTAB) {
 314                         continue;
 315                 }
 316                 sec->strtab = malloc(sec->shdr.sh_size);
 317                 if (!sec->strtab) {
 318                         die("malloc of %d bytes for strtab failed\n",
 319                                 sec->shdr.sh_size);
 320                 }
 321                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 322                         die("Seek to %d failed: %s\n",
 323                                 sec->shdr.sh_offset, strerror(errno));
 324                 }
 325                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 326                     != sec->shdr.sh_size) {
 327                         die("Cannot read symbol table: %s\n",
 328                                 strerror(errno));
 329                 }
 330         }
 331 }
 332
 333 static void read_symtabs(FILE *fp)
 334 {
 335         int i,j;
 336         for (i = 0; i < ehdr.e_shnum; i++) {
 337                 struct section *sec = &secs[i];
 338                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 339                         continue;
 340                 }
 341                 sec->symtab = malloc(sec->shdr.sh_size);
 342                 if (!sec->symtab) {
 343                         die("malloc of %d bytes for symtab failed\n",
 344                                 sec->shdr.sh_size);
 345                 }
 346                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 347                         die("Seek to %d failed: %s\n",
 348                                 sec->shdr.sh_offset, strerror(errno));
 349                 }
 350                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 351                     != sec->shdr.sh_size) {
 352                         die("Cannot read symbol table: %s\n",
 353                                 strerror(errno));
 354                 }
 355                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 356                         Elf32_Sym *sym = &sec->symtab[j];
 357                         sym->st_name  = elf32_to_cpu(sym->st_name);
 358                         sym->st_value = elf32_to_cpu(sym->st_value);
 359                         sym->st_size  = elf32_to_cpu(sym->st_size);
 360                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 361                 }
 362         }
 363 }
 364
 365
 366 static void read_relocs(FILE *fp)
 367 {
 368         int i,j;
 369         for (i = 0; i < ehdr.e_shnum; i++) {
 370                 struct section *sec = &secs[i];
 371                 if (sec->shdr.sh_type != SHT_REL) {
 372                         continue;
 373                 }
 374                 sec->reltab = malloc(sec->shdr.sh_size);
 375                 if (!sec->reltab) {
 376                         die("malloc of %d bytes for relocs failed\n",
 377                                 sec->shdr.sh_size);
 378                 }
 379                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 380                         die("Seek to %d failed: %s\n",
 381                                 sec->shdr.sh_offset, strerror(errno));
 382                 }
 383                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 384                     != sec->shdr.sh_size) {
 385                         die("Cannot read symbol table: %s\n",
 386                                 strerror(errno));
 387                 }
 388                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 389                         Elf32_Rel *rel = &sec->reltab[j];
 390                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 391                         rel->r_info   = elf32_to_cpu(rel->r_info);
 392                 }
 393         }
 394 }
 395
 396
 397 static void print_absolute_symbols(void)
 398 {
 399         int i;
 400         printf("Absolute symbols\n");
 401         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 402         for (i = 0; i < ehdr.e_shnum; i++) {
 403                 struct section *sec = &secs[i];
 404                 char *sym_strtab;
 405                 Elf32_Sym *sh_symtab;
 406                 int j;
 407
 408                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 409                         continue;
 410                 }
 411                 sh_symtab = sec->symtab;
 412                 sym_strtab = sec->link->strtab;
 413                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 414                         Elf32_Sym *sym;
 415                         const char *name;
 416                         sym = &sec->symtab[j];
 417                         name = sym_name(sym_strtab, sym);
 418                         if (sym->st_shndx != SHN_ABS) {
 419                                 continue;
 420                         }
 421                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 422                                 j, sym->st_value, sym->st_size,
 423                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 424                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 425                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 426                                 name);
 427                 }
 428         }
 429         printf("\n");
 430 }
 431
 432 static void print_absolute_relocs(void)
 433 {
 434         int i, printed = 0;
 435
 436         for (i = 0; i < ehdr.e_shnum; i++) {
 437                 struct section *sec = &secs[i];
 438                 struct section *sec_applies, *sec_symtab;
 439                 char *sym_strtab;
 440                 Elf32_Sym *sh_symtab;
 441                 int j;
 442                 if (sec->shdr.sh_type != SHT_REL) {
 443                         continue;
 444                 }
 445                 sec_symtab  = sec->link;
 446                 sec_applies = &secs[sec->shdr.sh_info];
 447                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 448                         continue;
 449                 }
 450                 sh_symtab  = sec_symtab->symtab;
 451                 sym_strtab = sec_symtab->link->strtab;
 452                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 453                         Elf32_Rel *rel;
 454                         Elf32_Sym *sym;
 455                         const char *name;
 456                         rel = &sec->reltab[j];
 457                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 458                         name = sym_name(sym_strtab, sym);
 459                         if (sym->st_shndx != SHN_ABS) {
 460                                 continue;
 461                         }
 462
 463                         /* Absolute symbols are not relocated if bzImage is
 464                          * loaded at a non-compiled address. Display a warning
 465                          * to user at compile time about the absolute
 466                          * relocations present.
 467                          *
 468                          * User need to audit the code to make sure
 469                          * some symbols which should have been section
 470                          * relative have not become absolute because of some
 471                          * linker optimization or wrong programming usage.
 472                          *
 473                          * Before warning check if this absolute symbol
 474                          * relocation is harmless.
 475                          */
 476                         if (is_abs_reloc(name) || is_rel_reloc(name))
 477                                 continue;
 478
 479                         if (!printed) {
 480                                 printf("WARNING: Absolute relocations"
 481                                         " present\n");
 482                                 printf("Offset     Info     Type     Sym.Value "
 483                                         "Sym.Name\n");
 484                                 printed = 1;
 485                         }
 486
 487                         printf("%08x %08x %10s %08x  %s\n",
 488                                 rel->r_offset,
 489                                 rel->r_info,
 490                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 491                                 sym->st_value,
 492                                 name);
 493                 }
 494         }
 495
 496         if (printed)
 497                 printf("\n");
 498 }
 499
 500 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
 501 {
 502         int i;
 503         /* Walk through the relocations */
 504         for (i = 0; i < ehdr.e_shnum; i++) {
 505                 char *sym_strtab;
 506                 Elf32_Sym *sh_symtab;
 507                 struct section *sec_applies, *sec_symtab;
 508                 int j;
 509                 struct section *sec = &secs[i];
 510
 511                 if (sec->shdr.sh_type != SHT_REL) {
 512                         continue;
 513                 }
 514                 sec_symtab  = sec->link;
 515                 sec_applies = &secs[sec->shdr.sh_info];
 516                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 517                         continue;
 518                 }
 519                 sh_symtab = sec_symtab->symtab;
 520                 sym_strtab = sec_symtab->link->strtab;
 521                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 522                         Elf32_Rel *rel;
 523                         Elf32_Sym *sym;
 524                         unsigned r_type;
 525                         rel = &sec->reltab[j];
 526                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 527                         r_type = ELF32_R_TYPE(rel->r_info);
 528                         /* Don't visit relocations to absolute symbols */
 529                         if (sym->st_shndx == SHN_ABS &&
 530                             !is_rel_reloc(sym_name(sym_strtab, sym))) {
 531                                 continue;
 532                         }
 533                         switch (r_type) {
 534                         case R_386_NONE:
 535                         case R_386_PC32:
 536                                 /*
 537                                  * NONE can be ignored and and PC relative
 538                                  * relocations don't need to be adjusted.
 539                                  */
 540                                 break;
 541                         case R_386_32:
 542                                 /* Visit relocations that need to be adjusted */
 543                                 visit(rel, sym);
 544                                 break;
 545                         default:
 546                                 die("Unsupported relocation type: %s (%d)\n",
 547                                     rel_type(r_type), r_type);
 548                                 break;
 549                         }
 550                 }
 551         }
 552 }
 553
 554 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 555 {
 556         reloc_count += 1;
 557 }
 558
 559 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 560 {
 561         /* Remember the address that needs to be adjusted. */
 562         relocs[reloc_idx++] = rel->r_offset;
 563 }
 564
 565 static int cmp_relocs(const void *va, const void *vb)
 566 {
 567         const unsigned long *a, *b;
 568         a = va; b = vb;
 569         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 570 }
 571
 572 static void emit_relocs(int as_text)
 573 {
 574         int i;
 575         /* Count how many relocations I have and allocate space for them. */
 576         reloc_count = 0;
 577         walk_relocs(count_reloc);
 578         relocs = malloc(reloc_count * sizeof(relocs[0]));
 579         if (!relocs) {
 580                 die("malloc of %d entries for relocs failed\n",
 581                         reloc_count);
 582         }
 583         /* Collect up the relocations */
 584         reloc_idx = 0;
 585         walk_relocs(collect_reloc);
 586
 587         /* Order the relocations for more efficient processing */
 588         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 589
 590         /* Print the relocations */
 591         if (as_text) {
 592                 /* Print the relocations in a form suitable that
 593                  * gas will like.
 594                  */
 595                 printf(".section \".data.reloc\",\"a\"\n");
 596                 printf(".balign 4\n");
 597                 for (i = 0; i < reloc_count; i++) {
 598                         printf("\t .long 0x%08lx\n", relocs[i]);
 599                 }
 600                 printf("\n");
 601         }
 602         else {
 603                 unsigned char buf[4];
 604                 /* Print a stop */
 605                 fwrite("\0\0\0\0", 4, 1, stdout);
 606                 /* Now print each relocation */
 607                 for (i = 0; i < reloc_count; i++) {
 608                         buf[0] = (relocs[i] >>  0) & 0xff;
 609                         buf[1] = (relocs[i] >>  8) & 0xff;
 610                         buf[2] = (relocs[i] >> 16) & 0xff;
 611                         buf[3] = (relocs[i] >> 24) & 0xff;
 612                         fwrite(buf, 4, 1, stdout);
 613                 }
 614         }
 615 }
 616
 617 static void usage(void)
 618 {
 619         die("relocs [--abs-syms |--abs-relocs | --text] vmlinux\n");
 620 }
 621
 622 int main(int argc, char **argv)
 623 {
 624         int show_absolute_syms, show_absolute_relocs;
 625         int as_text;
 626         const char *fname;
 627         FILE *fp;
 628         int i;
 629
 630         regex_init();
 631
 632         show_absolute_syms = 0;
 633         show_absolute_relocs = 0;
 634         as_text = 0;
 635         fname = NULL;
 636         for (i = 1; i < argc; i++) {
 637                 char *arg = argv[i];
 638                 if (*arg == '-') {
 639                         if (strcmp(argv[1], "--abs-syms") == 0) {
 640                                 show_absolute_syms = 1;
 641                                 continue;
 642                         }
 643
 644                         if (strcmp(argv[1], "--abs-relocs") == 0) {
 645                                 show_absolute_relocs = 1;
 646                                 continue;
 647                         }
 648                         else if (strcmp(argv[1], "--text") == 0) {
 649                                 as_text = 1;
 650                                 continue;
 651                         }
 652                 }
 653                 else if (!fname) {
 654                         fname = arg;
 655                         continue;
 656                 }
 657                 usage();
 658         }
 659         if (!fname) {
 660                 usage();
 661         }
 662         fp = fopen(fname, "r");
 663         if (!fp) {
 664                 die("Cannot open %s: %s\n",
 665                         fname, strerror(errno));
 666         }
 667         read_ehdr(fp);
 668         read_shdrs(fp);
 669         read_strtabs(fp);
 670         read_symtabs(fp);
 671         read_relocs(fp);
 672         if (show_absolute_syms) {
 673                 print_absolute_symbols();
 674                 return 0;
 675         }
 676         if (show_absolute_relocs) {
 677                 print_absolute_relocs();
 678                 return 0;
 679         }
 680         emit_relocs(as_text);
 681         return 0;
 682 }