com32/tools/relocs.c

   1 /*
   2  * This file is taken from the Linux kernel and is distributed under GPL v2.
   3  */
   4 #include <stdio.h>
   5 #include <stdarg.h>
   6 #include <stdlib.h>
   7 #include <stdint.h>
   8 #include <string.h>
   9 #include <errno.h>
  10 #include <unistd.h>
  11 #include <elf.h>
  12 #include <byteswap.h>
  13 #define USE_BSD
  14 #include <endian.h>
  15 #include <regex.h>
  16 #include <tools/le_byteshift.h>
  17
  18 static void die(char *fmt, ...);
  19
  20 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  21 static Elf32_Ehdr ehdr;
  22 static unsigned long reloc_count, reloc_idx;
  23 static unsigned long *relocs;
  24 static unsigned long reloc16_count, reloc16_idx;
  25 static unsigned long *relocs16;
  26
  27 struct section {
  28         Elf32_Shdr     shdr;
  29         struct section *link;
  30         Elf32_Sym      *symtab;
  31         Elf32_Rel      *reltab;
  32         char           *strtab;
  33 };
  34 static struct section *secs;
  35
  36 enum symtype {
  37         S_ABS,
  38         S_REL,
  39         S_SEG,
  40         S_LIN,
  41         S_NSYMTYPES
  42 };
  43
  44 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
  45 /*
  46  * Following symbols have been audited.  Don't warn user about
  47  * absolute relocations present w.r.t these symbols.
  48  */
  49         [S_ABS] =
  50         "^(__.*_len|__.*_dwords)$",
  51
  52 /*
  53  * These symbols are known to be relative, even if the linker marks them
  54  * as absolute (typically defined outside any section in the linker script.)
  55  */
  56         [S_REL] =
  57         "^(__.*_start|__.*_end|_end|_[se](text|data))$",
  58 };
  59
  60
  61 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
  62 /*
  63  * These are 16-bit segment symbols when compiling 16-bit code.
  64  */
  65         [S_SEG] =
  66         "^real_mode_seg$",
  67
  68 /*
  69  * These are offsets belonging to segments, as opposed to linear addresses,
  70  * when compiling 16-bit code.
  71  */
  72         [S_LIN] =
  73         "^pa_",
  74 };
  75
  76 static const char * const *sym_regex;
  77
  78 static regex_t sym_regex_c[S_NSYMTYPES];
  79 static int is_reloc(enum symtype type, const char *sym_name)
  80 {
  81         return sym_regex[type] &&
  82                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
  83 }
  84
  85 static void regex_init(int use_real_mode)
  86 {
  87         char errbuf[128];
  88         int err;
  89         int i;
  90
  91         if (use_real_mode)
  92                 sym_regex = sym_regex_realmode;
  93         else
  94                 sym_regex = sym_regex_kernel;
  95
  96         for (i = 0; i < S_NSYMTYPES; i++) {
  97                 if (!sym_regex[i])
  98                         continue;
  99
 100                 err = regcomp(&sym_regex_c[i], sym_regex[i],
 101                               REG_EXTENDED|REG_NOSUB);
 102
 103                 if (err) {
 104                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
 105                         die("%s", errbuf);
 106                 }
 107         }
 108 }
 109
 110 static void die(char *fmt, ...)
 111 {
 112         va_list ap;
 113         va_start(ap, fmt);
 114         vfprintf(stderr, fmt, ap);
 115         va_end(ap);
 116         exit(1);
 117 }
 118
 119 static const char *sym_type(unsigned type)
 120 {
 121         static const char *type_name[] = {
 122 #define SYM_TYPE(X) [X] = #X
 123                 SYM_TYPE(STT_NOTYPE),
 124                 SYM_TYPE(STT_OBJECT),
 125                 SYM_TYPE(STT_FUNC),
 126                 SYM_TYPE(STT_SECTION),
 127                 SYM_TYPE(STT_FILE),
 128                 SYM_TYPE(STT_COMMON),
 129                 SYM_TYPE(STT_TLS),
 130 #undef SYM_TYPE
 131         };
 132         const char *name = "unknown sym type name";
 133         if (type < ARRAY_SIZE(type_name)) {
 134                 name = type_name[type];
 135         }
 136         return name;
 137 }
 138
 139 static const char *sym_bind(unsigned bind)
 140 {
 141         static const char *bind_name[] = {
 142 #define SYM_BIND(X) [X] = #X
 143                 SYM_BIND(STB_LOCAL),
 144                 SYM_BIND(STB_GLOBAL),
 145                 SYM_BIND(STB_WEAK),
 146 #undef SYM_BIND
 147         };
 148         const char *name = "unknown sym bind name";
 149         if (bind < ARRAY_SIZE(bind_name)) {
 150                 name = bind_name[bind];
 151         }
 152         return name;
 153 }
 154
 155 static const char *sym_visibility(unsigned visibility)
 156 {
 157         static const char *visibility_name[] = {
 158 #define SYM_VISIBILITY(X) [X] = #X
 159                 SYM_VISIBILITY(STV_DEFAULT),
 160                 SYM_VISIBILITY(STV_INTERNAL),
 161                 SYM_VISIBILITY(STV_HIDDEN),
 162                 SYM_VISIBILITY(STV_PROTECTED),
 163 #undef SYM_VISIBILITY
 164         };
 165         const char *name = "unknown sym visibility name";
 166         if (visibility < ARRAY_SIZE(visibility_name)) {
 167                 name = visibility_name[visibility];
 168         }
 169         return name;
 170 }
 171
 172 static const char *rel_type(unsigned type)
 173 {
 174         static const char *type_name[] = {
 175 #define REL_TYPE(X) [X] = #X
 176                 REL_TYPE(R_386_NONE),
 177                 REL_TYPE(R_386_32),
 178                 REL_TYPE(R_386_PC32),
 179                 REL_TYPE(R_386_GOT32),
 180                 REL_TYPE(R_386_PLT32),
 181                 REL_TYPE(R_386_COPY),
 182                 REL_TYPE(R_386_GLOB_DAT),
 183                 REL_TYPE(R_386_JMP_SLOT),
 184                 REL_TYPE(R_386_RELATIVE),
 185                 REL_TYPE(R_386_GOTOFF),
 186                 REL_TYPE(R_386_GOTPC),
 187                 REL_TYPE(R_386_8),
 188                 REL_TYPE(R_386_PC8),
 189                 REL_TYPE(R_386_16),
 190                 REL_TYPE(R_386_PC16),
 191 #undef REL_TYPE
 192         };
 193         const char *name = "unknown type rel type name";
 194         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
 195                 name = type_name[type];
 196         }
 197         return name;
 198 }
 199
 200 static const char *sec_name(unsigned shndx)
 201 {
 202         const char *sec_strtab;
 203         const char *name;
 204         sec_strtab = secs[ehdr.e_shstrndx].strtab;
 205         name = "<noname>";
 206         if (shndx < ehdr.e_shnum) {
 207                 name = sec_strtab + secs[shndx].shdr.sh_name;
 208         }
 209         else if (shndx == SHN_ABS) {
 210                 name = "ABSOLUTE";
 211         }
 212         else if (shndx == SHN_COMMON) {
 213                 name = "COMMON";
 214         }
 215         return name;
 216 }
 217
 218 static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
 219 {
 220         const char *name;
 221         name = "<noname>";
 222         if (sym->st_name) {
 223                 name = sym_strtab + sym->st_name;
 224         }
 225         else {
 226                 name = sec_name(sym->st_shndx);
 227         }
 228         return name;
 229 }
 230
 231
 232
 233 #if BYTE_ORDER == LITTLE_ENDIAN
 234 #define le16_to_cpu(val) (val)
 235 #define le32_to_cpu(val) (val)
 236 #endif
 237 #if BYTE_ORDER == BIG_ENDIAN
 238 #define le16_to_cpu(val) bswap_16(val)
 239 #define le32_to_cpu(val) bswap_32(val)
 240 #endif
 241
 242 static uint16_t elf16_to_cpu(uint16_t val)
 243 {
 244         return le16_to_cpu(val);
 245 }
 246
 247 static uint32_t elf32_to_cpu(uint32_t val)
 248 {
 249         return le32_to_cpu(val);
 250 }
 251
 252 static void read_ehdr(FILE *fp)
 253 {
 254         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
 255                 die("Cannot read ELF header: %s\n",
 256                         strerror(errno));
 257         }
 258         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
 259                 die("No ELF magic\n");
 260         }
 261         if (ehdr.e_ident[EI_CLASS] != ELFCLASS32) {
 262                 die("Not a 32 bit executable\n");
 263         }
 264         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
 265                 die("Not a LSB ELF executable\n");
 266         }
 267         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
 268                 die("Unknown ELF version\n");
 269         }
 270         /* Convert the fields to native endian */
 271         ehdr.e_type      = elf16_to_cpu(ehdr.e_type);
 272         ehdr.e_machine   = elf16_to_cpu(ehdr.e_machine);
 273         ehdr.e_version   = elf32_to_cpu(ehdr.e_version);
 274         ehdr.e_entry     = elf32_to_cpu(ehdr.e_entry);
 275         ehdr.e_phoff     = elf32_to_cpu(ehdr.e_phoff);
 276         ehdr.e_shoff     = elf32_to_cpu(ehdr.e_shoff);
 277         ehdr.e_flags     = elf32_to_cpu(ehdr.e_flags);
 278         ehdr.e_ehsize    = elf16_to_cpu(ehdr.e_ehsize);
 279         ehdr.e_phentsize = elf16_to_cpu(ehdr.e_phentsize);
 280         ehdr.e_phnum     = elf16_to_cpu(ehdr.e_phnum);
 281         ehdr.e_shentsize = elf16_to_cpu(ehdr.e_shentsize);
 282         ehdr.e_shnum     = elf16_to_cpu(ehdr.e_shnum);
 283         ehdr.e_shstrndx  = elf16_to_cpu(ehdr.e_shstrndx);
 284
 285         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
 286                 die("Unsupported ELF header type\n");
 287         }
 288         if (ehdr.e_machine != EM_386) {
 289                 die("Not for x86\n");
 290         }
 291         if (ehdr.e_version != EV_CURRENT) {
 292                 die("Unknown ELF version\n");
 293         }
 294         if (ehdr.e_ehsize != sizeof(Elf32_Ehdr)) {
 295                 die("Bad Elf header size\n");
 296         }
 297         if (ehdr.e_phentsize != sizeof(Elf32_Phdr)) {
 298                 die("Bad program header entry\n");
 299         }
 300         if (ehdr.e_shentsize != sizeof(Elf32_Shdr)) {
 301                 die("Bad section header entry\n");
 302         }
 303         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
 304                 die("String table index out of bounds\n");
 305         }
 306 }
 307
 308 static void read_shdrs(FILE *fp)
 309 {
 310         int i;
 311         Elf32_Shdr shdr;
 312
 313         secs = calloc(ehdr.e_shnum, sizeof(struct section));
 314         if (!secs) {
 315                 die("Unable to allocate %d section headers\n",
 316                     ehdr.e_shnum);
 317         }
 318         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
 319                 die("Seek to %d failed: %s\n",
 320                         ehdr.e_shoff, strerror(errno));
 321         }
 322         for (i = 0; i < ehdr.e_shnum; i++) {
 323                 struct section *sec = &secs[i];
 324                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
 325                         die("Cannot read ELF section headers %d/%d: %s\n",
 326                             i, ehdr.e_shnum, strerror(errno));
 327                 sec->shdr.sh_name      = elf32_to_cpu(shdr.sh_name);
 328                 sec->shdr.sh_type      = elf32_to_cpu(shdr.sh_type);
 329                 sec->shdr.sh_flags     = elf32_to_cpu(shdr.sh_flags);
 330                 sec->shdr.sh_addr      = elf32_to_cpu(shdr.sh_addr);
 331                 sec->shdr.sh_offset    = elf32_to_cpu(shdr.sh_offset);
 332                 sec->shdr.sh_size      = elf32_to_cpu(shdr.sh_size);
 333                 sec->shdr.sh_link      = elf32_to_cpu(shdr.sh_link);
 334                 sec->shdr.sh_info      = elf32_to_cpu(shdr.sh_info);
 335                 sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
 336                 sec->shdr.sh_entsize   = elf32_to_cpu(shdr.sh_entsize);
 337                 if (sec->shdr.sh_link < ehdr.e_shnum)
 338                         sec->link = &secs[sec->shdr.sh_link];
 339         }
 340
 341 }
 342
 343 static void read_strtabs(FILE *fp)
 344 {
 345         int i;
 346         for (i = 0; i < ehdr.e_shnum; i++) {
 347                 struct section *sec = &secs[i];
 348                 if (sec->shdr.sh_type != SHT_STRTAB) {
 349                         continue;
 350                 }
 351                 sec->strtab = malloc(sec->shdr.sh_size);
 352                 if (!sec->strtab) {
 353                         die("malloc of %d bytes for strtab failed\n",
 354                                 sec->shdr.sh_size);
 355                 }
 356                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 357                         die("Seek to %d failed: %s\n",
 358                                 sec->shdr.sh_offset, strerror(errno));
 359                 }
 360                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
 361                     != sec->shdr.sh_size) {
 362                         die("Cannot read symbol table: %s\n",
 363                                 strerror(errno));
 364                 }
 365         }
 366 }
 367
 368 static void read_symtabs(FILE *fp)
 369 {
 370         int i,j;
 371         for (i = 0; i < ehdr.e_shnum; i++) {
 372                 struct section *sec = &secs[i];
 373                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 374                         continue;
 375                 }
 376                 sec->symtab = malloc(sec->shdr.sh_size);
 377                 if (!sec->symtab) {
 378                         die("malloc of %d bytes for symtab failed\n",
 379                                 sec->shdr.sh_size);
 380                 }
 381                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 382                         die("Seek to %d failed: %s\n",
 383                                 sec->shdr.sh_offset, strerror(errno));
 384                 }
 385                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
 386                     != sec->shdr.sh_size) {
 387                         die("Cannot read symbol table: %s\n",
 388                                 strerror(errno));
 389                 }
 390                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 391                         Elf32_Sym *sym = &sec->symtab[j];
 392                         sym->st_name  = elf32_to_cpu(sym->st_name);
 393                         sym->st_value = elf32_to_cpu(sym->st_value);
 394                         sym->st_size  = elf32_to_cpu(sym->st_size);
 395                         sym->st_shndx = elf16_to_cpu(sym->st_shndx);
 396                 }
 397         }
 398 }
 399
 400
 401 static void read_relocs(FILE *fp)
 402 {
 403         int i,j;
 404         for (i = 0; i < ehdr.e_shnum; i++) {
 405                 struct section *sec = &secs[i];
 406                 if (sec->shdr.sh_type != SHT_REL) {
 407                         continue;
 408                 }
 409                 sec->reltab = malloc(sec->shdr.sh_size);
 410                 if (!sec->reltab) {
 411                         die("malloc of %d bytes for relocs failed\n",
 412                                 sec->shdr.sh_size);
 413                 }
 414                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
 415                         die("Seek to %d failed: %s\n",
 416                                 sec->shdr.sh_offset, strerror(errno));
 417                 }
 418                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
 419                     != sec->shdr.sh_size) {
 420                         die("Cannot read symbol table: %s\n",
 421                                 strerror(errno));
 422                 }
 423                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 424                         Elf32_Rel *rel = &sec->reltab[j];
 425                         rel->r_offset = elf32_to_cpu(rel->r_offset);
 426                         rel->r_info   = elf32_to_cpu(rel->r_info);
 427                 }
 428         }
 429 }
 430
 431
 432 static void print_absolute_symbols(void)
 433 {
 434         int i;
 435         printf("Absolute symbols\n");
 436         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
 437         for (i = 0; i < ehdr.e_shnum; i++) {
 438                 struct section *sec = &secs[i];
 439                 char *sym_strtab;
 440                 int j;
 441
 442                 if (sec->shdr.sh_type != SHT_SYMTAB) {
 443                         continue;
 444                 }
 445                 sym_strtab = sec->link->strtab;
 446                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
 447                         Elf32_Sym *sym;
 448                         const char *name;
 449                         sym = &sec->symtab[j];
 450                         name = sym_name(sym_strtab, sym);
 451                         if (sym->st_shndx != SHN_ABS) {
 452                                 continue;
 453                         }
 454                         printf("%5d %08x %5d %10s %10s %12s %s\n",
 455                                 j, sym->st_value, sym->st_size,
 456                                 sym_type(ELF32_ST_TYPE(sym->st_info)),
 457                                 sym_bind(ELF32_ST_BIND(sym->st_info)),
 458                                 sym_visibility(ELF32_ST_VISIBILITY(sym->st_other)),
 459                                 name);
 460                 }
 461         }
 462         printf("\n");
 463 }
 464
 465 static void print_absolute_relocs(void)
 466 {
 467         int i, printed = 0;
 468
 469         for (i = 0; i < ehdr.e_shnum; i++) {
 470                 struct section *sec = &secs[i];
 471                 struct section *sec_applies, *sec_symtab;
 472                 char *sym_strtab;
 473                 Elf32_Sym *sh_symtab;
 474                 int j;
 475                 if (sec->shdr.sh_type != SHT_REL) {
 476                         continue;
 477                 }
 478                 sec_symtab  = sec->link;
 479                 sec_applies = &secs[sec->shdr.sh_info];
 480                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 481                         continue;
 482                 }
 483                 sh_symtab  = sec_symtab->symtab;
 484                 sym_strtab = sec_symtab->link->strtab;
 485                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 486                         Elf32_Rel *rel;
 487                         Elf32_Sym *sym;
 488                         const char *name;
 489                         rel = &sec->reltab[j];
 490                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 491                         name = sym_name(sym_strtab, sym);
 492                         if (sym->st_shndx != SHN_ABS) {
 493                                 continue;
 494                         }
 495
 496                         /* Absolute symbols are not relocated if bzImage is
 497                          * loaded at a non-compiled address. Display a warning
 498                          * to user at compile time about the absolute
 499                          * relocations present.
 500                          *
 501                          * User need to audit the code to make sure
 502                          * some symbols which should have been section
 503                          * relative have not become absolute because of some
 504                          * linker optimization or wrong programming usage.
 505                          *
 506                          * Before warning check if this absolute symbol
 507                          * relocation is harmless.
 508                          */
 509                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
 510                                 continue;
 511
 512                         if (!printed) {
 513                                 printf("WARNING: Absolute relocations"
 514                                         " present\n");
 515                                 printf("Offset     Info     Type     Sym.Value "
 516                                         "Sym.Name\n");
 517                                 printed = 1;
 518                         }
 519
 520                         printf("%08x %08x %10s %08x  %s\n",
 521                                 rel->r_offset,
 522                                 rel->r_info,
 523                                 rel_type(ELF32_R_TYPE(rel->r_info)),
 524                                 sym->st_value,
 525                                 name);
 526                 }
 527         }
 528
 529         if (printed)
 530                 printf("\n");
 531 }
 532
 533 static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym),
 534                         int use_real_mode)
 535 {
 536         int i;
 537         /* Walk through the relocations */
 538         for (i = 0; i < ehdr.e_shnum; i++) {
 539                 char *sym_strtab;
 540                 Elf32_Sym *sh_symtab;
 541                 struct section *sec_applies, *sec_symtab;
 542                 int j;
 543                 struct section *sec = &secs[i];
 544
 545                 if (sec->shdr.sh_type != SHT_REL) {
 546                         continue;
 547                 }
 548                 sec_symtab  = sec->link;
 549                 sec_applies = &secs[sec->shdr.sh_info];
 550                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
 551                         continue;
 552                 }
 553                 sh_symtab = sec_symtab->symtab;
 554                 sym_strtab = sec_symtab->link->strtab;
 555                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
 556                         Elf32_Rel *rel;
 557                         Elf32_Sym *sym;
 558                         unsigned r_type;
 559                         const char *symname;
 560                         int shn_abs;
 561
 562                         rel = &sec->reltab[j];
 563                         sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
 564                         r_type = ELF32_R_TYPE(rel->r_info);
 565
 566                         shn_abs = sym->st_shndx == SHN_ABS;
 567
 568                         switch (r_type) {
 569                         case R_386_NONE:
 570                         case R_386_PC32:
 571                         case R_386_PC16:
 572                         case R_386_PC8:
 573                         case R_386_GOTPC:
 574                         case R_386_GOTOFF:
 575                         case R_386_GOT32:
 576                         case R_386_PLT32:
 577                                 /*
 578                                  * NONE can be ignored and and PC relative
 579                                  * relocations don't need to be adjusted.
 580                                  */
 581                                 break;
 582
 583                         case R_386_16:
 584                                 symname = sym_name(sym_strtab, sym);
 585                                 if (!use_real_mode)
 586                                         goto bad;
 587                                 if (shn_abs) {
 588                                         if (is_reloc(S_ABS, symname))
 589                                                 break;
 590                                         else if (!is_reloc(S_SEG, symname))
 591                                                 goto bad;
 592                                 } else {
 593                                         if (is_reloc(S_LIN, symname))
 594                                                 goto bad;
 595                                         else
 596                                                 break;
 597                                 }
 598                                 visit(rel, sym);
 599                                 break;
 600
 601                         case R_386_32:
 602                                 symname = sym_name(sym_strtab, sym);
 603                                 if (shn_abs) {
 604                                         if (is_reloc(S_ABS, symname))
 605                                                 break;
 606                                         else if (!is_reloc(S_REL, symname))
 607                                                 goto bad;
 608                                 } else {
 609                                         if (use_real_mode &&
 610                                             !is_reloc(S_LIN, symname))
 611                                                 break;
 612                                 }
 613                                 visit(rel, sym);
 614                                 break;
 615                         default:
 616                                 die("Unsupported relocation type: %s (%d)\n",
 617                                     rel_type(r_type), r_type);
 618                                 break;
 619                         bad:
 620                                 symname = sym_name(sym_strtab, sym);
 621                                 die("Invalid %s %s relocation: %s\n",
 622                                     shn_abs ? "absolute" : "relative",
 623                                     rel_type(r_type), symname);
 624                         }
 625                 }
 626         }
 627 }
 628
 629 static void count_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 630 {
 631         (void)sym;
 632
 633         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 634                 reloc16_count++;
 635         else
 636                 reloc_count++;
 637 }
 638
 639 static void collect_reloc(Elf32_Rel *rel, Elf32_Sym *sym)
 640 {
 641         (void)sym;
 642
 643         /* Remember the address that needs to be adjusted. */
 644         if (ELF32_R_TYPE(rel->r_info) == R_386_16)
 645                 relocs16[reloc16_idx++] = rel->r_offset;
 646         else
 647                 relocs[reloc_idx++] = rel->r_offset;
 648 }
 649
 650 static int cmp_relocs(const void *va, const void *vb)
 651 {
 652         const unsigned long *a, *b;
 653         a = va; b = vb;
 654         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
 655 }
 656
 657 static int write32(unsigned int v, FILE *f)
 658 {
 659         unsigned char buf[4];
 660
 661         put_unaligned_le32(v, buf);
 662         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
 663 }
 664
 665 static void emit_relocs(int as_text, int use_real_mode)
 666 {
 667         int i;
 668         /* Count how many relocations I have and allocate space for them. */
 669         reloc_count = 0;
 670         walk_relocs(count_reloc, use_real_mode);
 671         relocs = malloc(reloc_count * sizeof(relocs[0]));
 672         if (!relocs) {
 673                 die("malloc of %d entries for relocs failed\n",
 674                         reloc_count);
 675         }
 676
 677         relocs16 = malloc(reloc16_count * sizeof(relocs[0]));
 678         if (!relocs16) {
 679                 die("malloc of %d entries for relocs16 failed\n",
 680                         reloc16_count);
 681         }
 682         /* Collect up the relocations */
 683         reloc_idx = 0;
 684         walk_relocs(collect_reloc, use_real_mode);
 685
 686         if (reloc16_count && !use_real_mode)
 687                 die("Segment relocations found but --realmode not specified\n");
 688
 689         /* Order the relocations for more efficient processing */
 690         qsort(relocs, reloc_count, sizeof(relocs[0]), cmp_relocs);
 691         qsort(relocs16, reloc16_count, sizeof(relocs16[0]), cmp_relocs);
 692
 693         /* Print the relocations */
 694         if (as_text) {
 695                 /* Print the relocations in a form suitable that
 696                  * gas will like.
 697                  */
 698                 printf(".section \".data.reloc\",\"a\"\n");
 699                 printf(".balign 4\n");
 700                 if (use_real_mode) {
 701                         printf("\t.long %lu\n", reloc16_count);
 702                         for (i = 0; i < reloc16_count; i++)
 703                                 printf("\t.long 0x%08lx\n", relocs16[i]);
 704                         printf("\t.long %lu\n", reloc_count);
 705                         for (i = 0; i < reloc_count; i++) {
 706                                 printf("\t.long 0x%08lx\n", relocs[i]);
 707                         }
 708                 } else {
 709                         for (i = 0; i < reloc_count; i++) {
 710                                 printf("\t.long 0x%08lx\n", relocs[i]);
 711                         }
 712                         /* Print a stop */
 713                         printf("\t.long 0x%08lx\n", (unsigned long)0);
 714                 }
 715
 716                 printf("\n");
 717         }
 718         else {
 719                 if (use_real_mode) {
 720                         write32(reloc16_count, stdout);
 721                         for (i = 0; i < reloc16_count; i++)
 722                                 write32(relocs16[i], stdout);
 723                         write32(reloc_count, stdout);
 724
 725                         /* Now print each relocation */
 726                         for (i = 0; i < reloc_count; i++)
 727                                 write32(relocs[i], stdout);
 728                 } else {
 729                         /* Now print each relocation */
 730                         for (i = 0; i < reloc_count; i++) {
 731                                 write32(relocs[i], stdout);
 732                         }
 733
 734                         /* Print a stop */
 735                         write32(0, stdout);
 736                 }
 737         }
 738 }
 739
 740 static void usage(void)
 741 {
 742         die("relocs [--abs-syms|--abs-relocs|--text|--realmode] vmlinux\n");
 743 }
 744
 745 int main(int argc, char **argv)
 746 {
 747         int show_absolute_syms, show_absolute_relocs;
 748         int as_text, use_real_mode;
 749         const char *fname;
 750         FILE *fp;
 751         int i;
 752
 753         show_absolute_syms = 0;
 754         show_absolute_relocs = 0;
 755         as_text = 0;
 756         use_real_mode = 0;
 757         fname = NULL;
 758         for (i = 1; i < argc; i++) {
 759                 char *arg = argv[i];
 760                 if (*arg == '-') {
 761                         if (strcmp(arg, "--abs-syms") == 0) {
 762                                 show_absolute_syms = 1;
 763                                 continue;
 764                         }
 765                         if (strcmp(arg, "--abs-relocs") == 0) {
 766                                 show_absolute_relocs = 1;
 767                                 continue;
 768                         }
 769                         if (strcmp(arg, "--text") == 0) {
 770                                 as_text = 1;
 771                                 continue;
 772                         }
 773                         if (strcmp(arg, "--realmode") == 0) {
 774                                 use_real_mode = 1;
 775                                 continue;
 776                         }
 777                 }
 778                 else if (!fname) {
 779                         fname = arg;
 780                         continue;
 781                 }
 782                 usage();
 783         }
 784         if (!fname) {
 785                 usage();
 786         }
 787         regex_init(use_real_mode);
 788         fp = fopen(fname, "r");
 789         if (!fp) {
 790                 die("Cannot open %s: %s\n",
 791                         fname, strerror(errno));
 792         }
 793         read_ehdr(fp);
 794         read_shdrs(fp);
 795         read_strtabs(fp);
 796         read_symtabs(fp);
 797         read_relocs(fp);
 798         if (show_absolute_syms) {
 799                 print_absolute_symbols();
 800                 return 0;
 801         }
 802         if (show_absolute_relocs) {
 803                 print_absolute_relocs();
 804                 return 0;
 805         }
 806         emit_relocs(as_text, use_real_mode);
 807         return 0;
 808 }