util/grub-pe2elf.c

   1 /* grub-pe2elf.c - tool to convert pe image to elf.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2008,2009 Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <grub/types.h>
  22 #include <grub/util/misc.h>
  23 #include <grub/elf.h>
  24 #include <grub/efi/pe32.h>
  25 #include <grub/misc.h>
  26
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <getopt.h>
  32
  33
  34 /* Please don't internationalise this file. It's pointless.  */
  35
  36 /*
  37  *  Section layout
  38  *
  39  *    null
  40  *    .text
  41  *    .rdata
  42  *    .data
  43  *    .bss
  44  *    .modname
  45  *    .moddeps
  46  *    .symtab
  47  *    .strtab
  48  *    relocation sections
  49  */
  50
  51 #if GRUB_TARGET_WORDSIZE == 64
  52 typedef Elf64_Rela elf_reloc_t;
  53 #define GRUB_PE32_MACHINE GRUB_PE32_MACHINE_X86_64
  54 #else
  55 typedef Elf32_Rel elf_reloc_t;
  56 #define GRUB_PE32_MACHINE GRUB_PE32_MACHINE_I386
  57 #endif
  58
  59 #define STRTAB_BLOCK    256
  60
  61 static char *strtab;
  62 static int strtab_max, strtab_len;
  63
  64 static Elf_Ehdr ehdr;
  65 static Elf_Shdr *shdr;
  66 static int num_sections, first_reloc_section, reloc_sections_end, symtab_section, strtab_section;
  67 static grub_uint32_t offset, image_base;
  68
  69 static int
  70 insert_string (const char *name)
  71 {
  72   int len, result;
  73
  74   if (*name == '_')
  75     name++;
  76
  77   len = strlen (name);
  78   if (strtab_len + len >= strtab_max)
  79     {
  80       strtab_max += STRTAB_BLOCK;
  81       strtab = xrealloc (strtab, strtab_max);
  82     }
  83
  84   strcpy (strtab + strtab_len, name);
  85   result = strtab_len;
  86   strtab_len += len + 1;
  87
  88   return result;
  89 }
  90
  91 static int *
  92 write_section_data (FILE* fp, const char *name, char *image,
  93                     struct grub_pe32_coff_header *pe_chdr,
  94                     struct grub_pe32_section_table *pe_shdr)
  95 {
  96   int *section_map;
  97   int i;
  98   grub_uint32_t last_category = 0;
  99   grub_uint32_t idx, idx_reloc;
 100   char *pe_strtab = (image + pe_chdr->symtab_offset
 101                      + pe_chdr->num_symbols * sizeof (struct grub_pe32_symbol));
 102
 103   section_map = xcalloc (2 * pe_chdr->num_sections + 5, sizeof (int));
 104   section_map[0] = 0;
 105   shdr = xcalloc (2 * pe_chdr->num_sections + 5, sizeof (shdr[0]));
 106   idx = 1;
 107   idx_reloc = pe_chdr->num_sections + 1;
 108
 109   for (i = 0; i < pe_chdr->num_sections; i++, pe_shdr++)
 110     {
 111       grub_uint32_t category;
 112       const char *shname = pe_shdr->name;
 113       grub_size_t secsize;
 114
 115       if (shname[0] == '/' && grub_isdigit (shname[1]))
 116       {
 117         char t[sizeof (pe_shdr->name) + 1];
 118         memcpy (t, shname, sizeof (pe_shdr->name));
 119         t[sizeof (pe_shdr->name)] = 0;
 120         shname = pe_strtab + atoi (t + 1);
 121       }
 122
 123       secsize = pe_shdr->raw_data_size;
 124
 125       shdr[idx].sh_type = SHT_PROGBITS;
 126
 127       if (! strcmp (shname, ".text"))
 128         {
 129           category = 0;
 130           shdr[idx].sh_flags = SHF_ALLOC | SHF_EXECINSTR;
 131         }
 132       else if (! strncmp (shname, ".rdata", 6))
 133         {
 134           category = 1;
 135           shdr[idx].sh_flags = SHF_ALLOC;
 136         }
 137       else if (! strcmp (shname, ".data"))
 138         {
 139           category = 2;
 140           shdr[idx].sh_flags = SHF_ALLOC | SHF_WRITE;
 141         }
 142       else if (! strcmp (shname, ".bss"))
 143         {
 144           category = 3;
 145           shdr[idx].sh_type = SHT_NOBITS;
 146           shdr[idx].sh_flags = SHF_ALLOC | SHF_WRITE;
 147           if (secsize < pe_shdr->virtual_size)
 148             secsize = pe_shdr->virtual_size;
 149         }
 150       else if (strcmp (shname, ".modname") == 0 || strcmp (shname, ".moddeps") == 0
 151                || strcmp (shname, ".module_license") == 0)
 152         category = 4;
 153       else
 154         {
 155           section_map[i + 1] = -1;
 156           continue;
 157         }
 158
 159       if (category < last_category)
 160         grub_util_error ("out of order sections");
 161
 162       section_map[i + 1] = idx;
 163
 164       if (pe_shdr->virtual_size
 165           && pe_shdr->virtual_size < secsize)
 166         secsize = pe_shdr->virtual_size;
 167
 168       shdr[idx].sh_size = secsize;
 169       shdr[idx].sh_addralign = 1 << (((pe_shdr->characteristics >>
 170                                        GRUB_PE32_SCN_ALIGN_SHIFT) &
 171                                       GRUB_PE32_SCN_ALIGN_MASK) - 1);
 172       shdr[idx].sh_addr = pe_shdr->virtual_address + image_base;
 173
 174       if (shdr[idx].sh_type != SHT_NOBITS)
 175         {
 176           shdr[idx].sh_offset = offset;
 177           grub_util_write_image_at (image + pe_shdr->raw_data_offset,
 178                                     pe_shdr->raw_data_size, offset, fp,
 179                                     shname);
 180
 181           offset += secsize;
 182         }
 183
 184       if (pe_shdr->relocations_offset)
 185         {
 186           char relname[5 + strlen (shname)];
 187
 188           sprintf (relname, ".rel%s", shname);
 189
 190           shdr[idx_reloc].sh_name = insert_string (relname);
 191           shdr[idx_reloc].sh_link = i;
 192           shdr[idx_reloc].sh_info = idx;
 193
 194           shdr[idx].sh_name = shdr[idx_reloc].sh_name + 4;
 195
 196           idx_reloc++;
 197         }
 198       else
 199         shdr[idx].sh_name = insert_string (shname);
 200       idx++;
 201     }
 202
 203   idx_reloc -= pe_chdr->num_sections + 1;
 204   num_sections = idx + idx_reloc + 2;
 205   first_reloc_section = idx;
 206   reloc_sections_end = idx + idx_reloc;
 207   memmove (shdr + idx, shdr + pe_chdr->num_sections + 1,
 208            idx_reloc * sizeof (shdr[0]));
 209   memset (shdr + idx + idx_reloc, 0, 3 * sizeof (shdr[0]));
 210   memset (shdr, 0, sizeof (shdr[0]));
 211
 212   symtab_section = idx + idx_reloc;
 213   strtab_section = idx + idx_reloc + 1;
 214
 215   return section_map;
 216 }
 217
 218 static void
 219 write_reloc_section (FILE* fp, const char *name, char *image,
 220                      struct grub_pe32_coff_header *pe_chdr,
 221                      struct grub_pe32_section_table  *pe_shdr,
 222                      Elf_Sym *symtab,
 223                      int *symtab_map)
 224 {
 225   int i;
 226
 227   for (i = first_reloc_section; i < reloc_sections_end; i++)
 228     {
 229       struct grub_pe32_section_table *pe_sec;
 230       struct grub_pe32_reloc *pe_rel;
 231       elf_reloc_t *rel;
 232       int num_rels, j, modified;
 233
 234       pe_sec = pe_shdr + shdr[i].sh_link;
 235       pe_rel = (struct grub_pe32_reloc *) (image + pe_sec->relocations_offset);
 236       rel = (elf_reloc_t *) xcalloc (pe_sec->num_relocations, sizeof (elf_reloc_t));
 237       num_rels = 0;
 238       modified = 0;
 239
 240       for (j = 0; j < pe_sec->num_relocations; j++, pe_rel++)
 241         {
 242           int type;
 243           grub_uint32_t ofs, *addr;
 244
 245           if ((pe_rel->symtab_index >= pe_chdr->num_symbols) ||
 246               (symtab_map[pe_rel->symtab_index] == -1))
 247             grub_util_error ("invalid symbol");
 248
 249           ofs = pe_rel->offset - pe_sec->virtual_address;
 250           addr = (grub_uint32_t *)(image + pe_sec->raw_data_offset + ofs);
 251
 252           switch (pe_rel->type)
 253             {
 254 #if GRUB_TARGET_WORDSIZE == 64
 255             case 1:
 256               type = R_X86_64_64;
 257               rel[num_rels].r_addend = *(grub_int64_t *)addr;
 258               *(grub_int64_t *)addr = 0;
 259               modified = 1;
 260               break;
 261             case 4:
 262               type = R_X86_64_PC32;
 263               rel[num_rels].r_addend = *(grub_int32_t *)addr;
 264               *addr = 0;
 265               modified = 1;
 266               break;
 267             case 14:
 268               type = R_X86_64_PC64;
 269               rel[num_rels].r_addend = *(grub_uint64_t *)addr - 8;
 270               *(grub_uint64_t *)addr = 0;
 271               modified = 1;
 272               break;
 273 #else
 274             case GRUB_PE32_REL_I386_DIR32:
 275               type = R_386_32;
 276               break;
 277             case GRUB_PE32_REL_I386_REL32:
 278               type = R_386_PC32;
 279               break;
 280 #endif
 281             default:
 282               grub_util_error ("unknown pe relocation type %d", pe_rel->type);
 283             }
 284
 285           if (type ==
 286 #if GRUB_TARGET_WORDSIZE == 64
 287               R_386_PC32
 288 #else
 289               R_X86_64_PC32
 290 #endif
 291
 292               )
 293             {
 294               unsigned char code;
 295
 296               code = image[pe_sec->raw_data_offset + ofs - 1];
 297
 298 #if GRUB_TARGET_WORDSIZE == 32
 299               if (((code != 0xe8) && (code != 0xe9)) || (*addr))
 300                 grub_util_error ("invalid relocation (%x %x)", code, *addr);
 301 #endif
 302
 303               if (symtab[symtab_map[pe_rel->symtab_index]].st_shndx
 304                   && symtab[symtab_map[pe_rel->symtab_index]].st_shndx
 305                   == shdr[i].sh_info)
 306                 {
 307                   modified = 1;
 308                   *addr += (symtab[symtab_map[pe_rel->symtab_index]].st_value
 309                             - ofs - 4);
 310
 311                   continue;
 312                 }
 313               else
 314                 {
 315 #if GRUB_TARGET_WORDSIZE == 64
 316                   rel[num_rels].r_addend -= 4;
 317 #else
 318                   modified = 1;
 319                   *addr = -4;
 320 #endif
 321                 }
 322             }
 323
 324           rel[num_rels].r_offset = ofs;
 325           rel[num_rels].r_info = ELF_R_INFO (symtab_map[pe_rel->symtab_index],
 326                                              type);
 327           num_rels++;
 328         }
 329
 330       if (modified)
 331         grub_util_write_image_at (image + pe_sec->raw_data_offset,
 332                                   shdr[shdr[i].sh_info].sh_size,
 333                                   shdr[shdr[i].sh_info].sh_offset,
 334                                   fp, name);
 335
 336 #if GRUB_TARGET_WORDSIZE == 64
 337       shdr[i].sh_type = SHT_RELA;
 338 #else
 339       shdr[i].sh_type = SHT_REL;
 340 #endif
 341       shdr[i].sh_offset = offset;
 342       shdr[i].sh_link = symtab_section;
 343       shdr[i].sh_addralign = 4;
 344       shdr[i].sh_entsize = sizeof (elf_reloc_t);
 345       shdr[i].sh_size = num_rels * sizeof (elf_reloc_t);
 346
 347       grub_util_write_image_at (rel, shdr[i].sh_size, offset, fp, name);
 348       offset += shdr[i].sh_size;
 349       free (rel);
 350     }
 351 }
 352
 353 static void
 354 write_symbol_table (FILE* fp, const char *name, char *image,
 355                     struct grub_pe32_coff_header *pe_chdr,
 356                     struct grub_pe32_section_table *pe_shdr,
 357                     int *section_map)
 358 {
 359   struct grub_pe32_symbol *pe_symtab;
 360   char *pe_strtab;
 361   Elf_Sym *symtab;
 362   int *symtab_map, num_syms;
 363   int i;
 364
 365   pe_symtab = (struct grub_pe32_symbol *) (image + pe_chdr->symtab_offset);
 366   pe_strtab = (char *) (pe_symtab + pe_chdr->num_symbols);
 367
 368   symtab = (Elf_Sym *) xcalloc (pe_chdr->num_symbols + 1, sizeof (Elf_Sym));
 369   num_syms = 1;
 370
 371   symtab_map = (int *) xcalloc (pe_chdr->num_symbols, sizeof (int));
 372
 373   for (i = 0; i < (int) pe_chdr->num_symbols;
 374        i += pe_symtab->num_aux + 1, pe_symtab += pe_symtab->num_aux + 1)
 375     {
 376       int bind, type;
 377
 378       symtab_map[i] = -1;
 379       if ((pe_symtab->section > pe_chdr->num_sections) ||
 380           (section_map[pe_symtab->section] == -1))
 381         continue;
 382
 383       if (! pe_symtab->section)
 384         type = STT_NOTYPE;
 385       else if (pe_symtab->type == GRUB_PE32_DT_FUNCTION)
 386         type = STT_FUNC;
 387       else
 388         type = STT_OBJECT;
 389
 390       if (pe_symtab->storage_class == GRUB_PE32_SYM_CLASS_EXTERNAL)
 391         bind = STB_GLOBAL;
 392       else
 393         bind = STB_LOCAL;
 394
 395       if ((pe_symtab->type != GRUB_PE32_DT_FUNCTION) && (pe_symtab->num_aux))
 396         {
 397           if (! pe_symtab->value)
 398             type = STT_SECTION;
 399
 400           symtab[num_syms].st_name = shdr[section_map[pe_symtab->section]].sh_name;
 401         }
 402       else
 403         {
 404           char short_name[9];
 405           char *symname;
 406
 407           if (pe_symtab->long_name[0])
 408             {
 409               strncpy (short_name, pe_symtab->short_name, 8);
 410               short_name[8] = 0;
 411               symname = short_name;
 412             }
 413           else
 414             symname = pe_strtab + pe_symtab->long_name[1];
 415
 416           if ((strcmp (symname, "_grub_mod_init")) &&
 417               (strcmp (symname, "_grub_mod_fini")) &&
 418               (strcmp (symname, "grub_mod_init")) &&
 419               (strcmp (symname, "grub_mod_fini")) &&
 420               (bind == STB_LOCAL))
 421               continue;
 422
 423           symtab[num_syms].st_name = insert_string (symname);
 424         }
 425
 426       symtab[num_syms].st_shndx = section_map[pe_symtab->section];
 427       symtab[num_syms].st_value = pe_symtab->value;
 428       symtab[num_syms].st_info = ELF_ST_INFO (bind, type);
 429
 430       symtab_map[i] = num_syms;
 431       num_syms++;
 432     }
 433
 434   write_reloc_section (fp, name, image, pe_chdr, pe_shdr,
 435                        symtab, symtab_map);
 436
 437   shdr[symtab_section].sh_name = insert_string (".symtab");
 438   shdr[symtab_section].sh_type = SHT_SYMTAB;
 439   shdr[symtab_section].sh_offset = offset;
 440   shdr[symtab_section].sh_size = num_syms * sizeof (Elf_Sym);
 441   shdr[symtab_section].sh_entsize = sizeof (Elf_Sym);
 442   shdr[symtab_section].sh_link = strtab_section;
 443   shdr[symtab_section].sh_addralign = 4;
 444
 445   grub_util_write_image_at (symtab, shdr[symtab_section].sh_size,
 446                             offset, fp, name);
 447   offset += shdr[symtab_section].sh_size;
 448
 449   free (symtab);
 450   free (symtab_map);
 451 }
 452
 453 static void
 454 write_string_table (FILE *fp, const char *name)
 455 {
 456   shdr[strtab_section].sh_name = insert_string (".strtab");
 457   shdr[strtab_section].sh_type = SHT_STRTAB;
 458   shdr[strtab_section].sh_offset = offset;
 459   shdr[strtab_section].sh_size = strtab_len;
 460   shdr[strtab_section].sh_addralign = 1;
 461   grub_util_write_image_at (strtab, strtab_len, offset, fp,
 462                             name);
 463   offset += strtab_len;
 464
 465   free (strtab);
 466 }
 467
 468 static void
 469 write_section_header (FILE *fp, const char *name)
 470 {
 471   ehdr.e_ident[EI_MAG0] = ELFMAG0;
 472   ehdr.e_ident[EI_MAG1] = ELFMAG1;
 473   ehdr.e_ident[EI_MAG2] = ELFMAG2;
 474   ehdr.e_ident[EI_MAG3] = ELFMAG3;
 475   ehdr.e_ident[EI_VERSION] = EV_CURRENT;
 476   ehdr.e_version = EV_CURRENT;
 477   ehdr.e_type = ET_REL;
 478
 479 #if GRUB_TARGET_WORDSIZE == 64
 480   ehdr.e_ident[EI_CLASS] = ELFCLASS64;
 481   ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
 482   ehdr.e_machine = EM_X86_64;
 483 #else
 484   ehdr.e_ident[EI_CLASS] = ELFCLASS32;
 485   ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
 486   ehdr.e_machine = EM_386;
 487 #endif
 488   ehdr.e_ehsize = sizeof (ehdr);
 489   ehdr.e_shentsize = sizeof (Elf_Shdr);
 490   ehdr.e_shstrndx = strtab_section;
 491
 492   ehdr.e_shoff = offset;
 493   ehdr.e_shnum = num_sections;
 494   grub_util_write_image_at (shdr, sizeof (Elf_Shdr) * num_sections,
 495                             offset, fp, name);
 496
 497   grub_util_write_image_at (&ehdr, sizeof (Elf_Ehdr), 0, fp, name);
 498 }
 499
 500 static void
 501 convert_pe (FILE* fp, const char *name, char *image)
 502 {
 503   struct grub_pe32_coff_header *pe_chdr;
 504   struct grub_pe32_section_table *pe_shdr;
 505   int *section_map;
 506
 507   if (image[0] == 'M' && image[1] == 'Z')
 508     pe_chdr = (struct grub_pe32_coff_header *) (image + (grub_le_to_cpu32 (((grub_uint32_t *)image)[0xf]) + 4));
 509   else
 510     pe_chdr = (struct grub_pe32_coff_header *) image;
 511   if (grub_le_to_cpu16 (pe_chdr->machine) != GRUB_PE32_MACHINE)
 512     grub_util_error ("invalid coff image (%x != %x)",
 513                      grub_le_to_cpu16 (pe_chdr->machine), GRUB_PE32_MACHINE);
 514
 515   strtab = xmalloc (STRTAB_BLOCK);
 516   strtab_max = STRTAB_BLOCK;
 517   strtab[0] = 0;
 518   strtab_len = 1;
 519
 520   offset = sizeof (ehdr);
 521   if (pe_chdr->optional_header_size)
 522     {
 523 #if GRUB_TARGET_WORDSIZE == 64
 524       struct grub_pe64_optional_header *o;
 525 #else
 526       struct grub_pe32_optional_header *o;
 527 #endif
 528       o = (void *) (pe_chdr + 1);
 529       image_base = o->image_base;
 530     }
 531   pe_shdr = (struct grub_pe32_section_table *) ((char *) (pe_chdr + 1) + pe_chdr->optional_header_size);
 532
 533   section_map = write_section_data (fp, name, image, pe_chdr, pe_shdr);
 534
 535   write_symbol_table (fp, name, image, pe_chdr, pe_shdr, section_map);
 536   free (section_map);
 537
 538   write_string_table (fp, name);
 539
 540   write_section_header (fp, name);
 541 }
 542
 543 int
 544 main (int argc, char *argv[])
 545 {
 546   char *image;
 547   FILE* fp;
 548   char *in, *out;
 549
 550   /* Obtain PATH.  */
 551   if (1 >= argc)
 552     {
 553       fprintf (stderr, "Filename not specified.\n");
 554       return 1;
 555     }
 556
 557   in = argv[1];
 558   if (argc > 2)
 559     out = argv[2];
 560   else
 561     out = in;
 562   image = grub_util_read_image (in);
 563
 564   fp = grub_util_fopen (out, "wb");
 565   if (! fp)
 566     grub_util_error ("cannot open %s", out);
 567
 568   convert_pe (fp, out, image);
 569
 570   fclose (fp);
 571
 572   return 0;
 573 }