AcessNative/ld-acess_src/elf.c

   1 /*\r
   2  * Acess v0.1\r
   3  * ELF Executable Loader Code\r
   4  */\r
   5 #define DEBUG   0\r
   6 #include <stdlib.h>\r
   7 #include <stdio.h>\r
   8 #include <string.h>\r
   9 #include <unistd.h>\r
  10 #include "common.h"\r
  11 #include "elf.h"\r
  12 \r
  13 #define DEBUG_WARN      1\r
  14 \r
  15 #define MKPTR(_type,_val)       ((_type*)(uintptr_t)(_val))\r
  16 #define PTRMK(_type,_val)       MKPTR(_type,_val)\r
  17 #define PTR(_val)       ((void*)(uintptr_t)(_val))\r
  18 \r
  19 #if DEBUG\r
  20 # define ENTER(...)\r
  21 # define LOG(s, ...)    printf("%s: " s, __func__, __VA_ARGS__)\r
  22 # define LOGS(s)        printf("%s: " s, __func__)\r
  23 # define LEAVE(...)\r
  24 #else\r
  25 # define ENTER(...)\r
  26 # define LOG(...)\r
  27 # define LOGS(...)\r
  28 # define LEAVE(...)\r
  29 #endif\r
  30 \r
  31 // === PROTOTYPES ===\r
  32 void    *Elf_Load(int FD);\r
  33 uintptr_t       Elf_Relocate(void *Base);\r
  34  int    Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret);\r
  35  int    Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *Base);\r
  36 uint32_t        Elf_Int_HashString(char *str);\r
  37 \r
  38 // === CODE ===\r
  39 void *Elf_Load(int FD)\r
  40 {\r
  41         Elf32_Ehdr      hdr;\r
  42         Elf32_Phdr      *phtab;\r
  43          int    i, j;\r
  44          int    iPageCount;\r
  45         uint32_t        max, base;\r
  46         uint32_t        addr;\r
  47         uint32_t        baseDiff = 0;\r
  48         \r
  49         ENTER("iFD", FD);\r
  50         \r
  51         // Read ELF Header\r
  52         acess_read(FD, sizeof(hdr), &hdr);\r
  53         \r
  54         // Check the file type\r
  55         if(hdr.ident[0] != 0x7F || hdr.ident[1] != 'E' || hdr.ident[2] != 'L' || hdr.ident[3] != 'F') {\r
  56                 Warning("Non-ELF File was passed to the ELF loader\n");\r
  57                 LEAVE('n');\r
  58                 return NULL;\r
  59         }\r
  60         \r
  61         // Check for a program header\r
  62         if(hdr.phoff == 0) {\r
  63                 #if DEBUG_WARN\r
  64                 Warning("ELF File does not contain a program header\n");\r
  65                 #endif\r
  66                 LEAVE('n');\r
  67                 return NULL;\r
  68         }\r
  69         \r
  70         // Read Program Header Table\r
  71         phtab = malloc( sizeof(Elf32_Phdr) * hdr.phentcount );\r
  72         if( !phtab ) {\r
  73                 LEAVE('n');\r
  74                 return NULL;\r
  75         }\r
  76         LOG("hdr.phoff = 0x%08x\n", hdr.phoff);\r
  77         acess_seek(FD, hdr.phoff, ACESS_SEEK_SET);\r
  78         acess_read(FD, sizeof(Elf32_Phdr) * hdr.phentcount, phtab);\r
  79         \r
  80         // Count Pages\r
  81         iPageCount = 0;\r
  82         LOG("hdr.phentcount = %i\n", hdr.phentcount);\r
  83         for( i = 0; i < hdr.phentcount; i++ )\r
  84         {\r
  85                 // Ignore Non-LOAD types\r
  86                 if(phtab[i].Type != PT_LOAD)\r
  87                         continue;\r
  88                 iPageCount += ((phtab[i].VAddr&0xFFF) + phtab[i].MemSize + 0xFFF) >> 12;\r
  89                 LOG("phtab[%i] = {VAddr:0x%x, MemSize:0x%x}\n", i, phtab[i].VAddr, phtab[i].MemSize);\r
  90         }\r
  91         \r
  92         LOG("iPageCount = %i\n", iPageCount);\r
  93         \r
  94         // Allocate Information Structure\r
  95         //ret = malloc( sizeof(tBinary) + sizeof(tBinaryPage)*iPageCount );\r
  96         // Fill Info Struct\r
  97         //ret->Entry = hdr.entrypoint;\r
  98         //ret->Base = -1;               // Set Base to maximum value\r
  99         //ret->NumPages = iPageCount;\r
 100         //ret->Interpreter = NULL;\r
 101 \r
 102         // Prescan for base and size\r
 103         max = 0;\r
 104         base = 0xFFFFFFFF;\r
 105         for( i = 0; i < hdr.phentcount; i ++)\r
 106         {\r
 107                 if( phtab[i].Type != PT_LOAD )\r
 108                         continue;\r
 109                 if( phtab[i].VAddr < base )\r
 110                         base = phtab[i].VAddr;\r
 111                 if( phtab[i].VAddr + phtab[i].MemSize > max )\r
 112                         max = phtab[i].VAddr + phtab[i].MemSize;\r
 113         }\r
 114 \r
 115         LOG("base = %08x, max = %08x\n", base, max);\r
 116 \r
 117         if( base == 0 ) {\r
 118                 // Find a nice space (31 address bits allowed)\r
 119                 base = FindFreeRange( max, 31 );\r
 120                 LOG("new base = %08x\n", base);\r
 121                 if( base == 0 ) return NULL;\r
 122                 baseDiff = base;\r
 123         }\r
 124         \r
 125         // Load Pages\r
 126         j = 0;\r
 127         for( i = 0; i < hdr.phentcount; i++ )\r
 128         {\r
 129                 //LOG("phtab[%i].Type = 0x%x", i, phtab[i].Type);\r
 130                 LOG("phtab[%i] = {\n", i);\r
 131                 LOG(" .Type = 0x%08x\n", phtab[i].Type);\r
 132                 LOG(" .Offset = 0x%08x\n", phtab[i].Offset);\r
 133                 LOG(" .VAddr = 0x%08x\n", phtab[i].VAddr);\r
 134                 LOG(" .PAddr = 0x%08x\n", phtab[i].PAddr);\r
 135                 LOG(" .FileSize = 0x%08x\n", phtab[i].FileSize);\r
 136                 LOG(" .MemSize = 0x%08x\n", phtab[i].MemSize);\r
 137                 LOG(" .Flags = 0x%08x\n", phtab[i].Flags);\r
 138                 LOG(" .Align = 0x%08x\n", phtab[i].Align);\r
 139                 LOGS(" }\n");\r
 140                 // Get Interpreter Name\r
 141                 if( phtab[i].Type == PT_INTERP )\r
 142                 {\r
 143                         char *tmp;\r
 144                         //if(ret->Interpreter)  continue;\r
 145                         tmp = malloc(phtab[i].FileSize);\r
 146                         acess_seek(FD, phtab[i].Offset, ACESS_SEEK_SET);\r
 147                         acess_read(FD, phtab[i].FileSize, tmp);\r
 148                         //ret->Interpreter = Binary_RegInterp(tmp);\r
 149                         LOG("Interpreter '%s'\n", tmp);\r
 150                         free(tmp);\r
 151                         continue;\r
 152                 }\r
 153                 // Ignore non-LOAD types\r
 154                 if(phtab[i].Type != PT_LOAD)    continue;\r
 155                 \r
 156                 LOG("phtab[%i] = {VAddr:0x%x,Offset:0x%x,FileSize:0x%x}\n",\r
 157                         i, phtab[i].VAddr+baseDiff, phtab[i].Offset, phtab[i].FileSize);\r
 158                 \r
 159                 addr = phtab[i].VAddr + baseDiff;\r
 160 \r
 161                 if( AllocateMemory( addr, phtab[i].MemSize ) ) {\r
 162                         fprintf(stderr, "Elf_Load: Unable to map memory at %x (0x%x bytes)\n",\r
 163                                 addr, phtab[i].MemSize);\r
 164                         free( phtab );\r
 165                         return NULL;\r
 166                 }\r
 167                 \r
 168                 acess_seek(FD, phtab[i].Offset, ACESS_SEEK_SET);\r
 169                 acess_read(FD, phtab[i].FileSize, PTRMK(void, addr) );\r
 170                 memset( PTRMK(char, addr) + phtab[i].FileSize, 0, phtab[i].MemSize - phtab[i].FileSize );\r
 171         }\r
 172         \r
 173         // Clean Up\r
 174         free(phtab);\r
 175         // Return\r
 176         LEAVE('p', base);\r
 177         return PTRMK(void, base);\r
 178 }\r
 179 \r
 180 // --- ELF RELOCATION ---\r
 181 /**\r
 182  * \brief Relocates a loaded ELF Executable\r
 183  */\r
 184 uintptr_t Elf_Relocate(void *Base)\r
 185 {\r
 186         Elf32_Ehdr      *hdr = Base;\r
 187         Elf32_Phdr      *phtab;\r
 188          int    i, j;   // Counters\r
 189         char    *libPath;\r
 190         uint32_t        iRealBase = -1;\r
 191         uintptr_t       iBaseDiff;\r
 192          int    iSegmentCount;\r
 193          int    iSymCount = 0;\r
 194         Elf32_Rel       *rel = NULL;\r
 195         Elf32_Rela      *rela = NULL;\r
 196         uint32_t        *pltgot = NULL;\r
 197         void    *plt = NULL;\r
 198         uint32_t        *ptr;\r
 199          int    relSz=0, relEntSz=8;\r
 200          int    relaSz=0, relaEntSz=8;\r
 201          int    pltSz=0, pltType=0;\r
 202         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer\r
 203         char    *dynstrtab = NULL;      // .dynamic String Table\r
 204         Elf32_Sym       *dynsymtab = NULL;\r
 205          int    bFailed = 0;\r
 206         \r
 207         ENTER("pBase", Base);\r
 208         LOG("Base = %p\n", Base);\r
 209         \r
 210         // Parse Program Header to get Dynamic Table\r
 211         phtab = Base + hdr->phoff;\r
 212         iSegmentCount = hdr->phentcount;\r
 213         for(i = 0; i < iSegmentCount; i ++ )\r
 214         {\r
 215                 // Determine linked base address\r
 216                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)\r
 217                         iRealBase = phtab[i].VAddr;\r
 218                 \r
 219                 // Find Dynamic Section\r
 220                 if(phtab[i].Type == PT_DYNAMIC) {\r
 221                         if(dynamicTab) {\r
 222                                 Warning("Elf_Relocate - Multiple PT_DYNAMIC segments\n");\r
 223                                 continue;\r
 224                         }\r
 225                         dynamicTab = MKPTR(void, phtab[i].VAddr);\r
 226                         j = i;  // Save Dynamic Table ID\r
 227                         break;\r
 228                 }\r
 229         }\r
 230         \r
 231         // Check if a PT_DYNAMIC segement was found\r
 232         if(!dynamicTab) {\r
 233                 Warning("Elf_Relocate: No PT_DYNAMIC segment in image, returning\n");\r
 234                 LEAVE('x', hdr->entrypoint);\r
 235                 return hdr->entrypoint;\r
 236         }\r
 237         \r
 238         // Page Align real base\r
 239         iRealBase &= ~0xFFF;\r
 240         \r
 241         LOG("dynamicTab = %p\n", dynamicTab);\r
 242         // Adjust "Real" Base\r
 243         iBaseDiff = (uintptr_t)Base - iRealBase;\r
 244         LOG("iBaseDiff = %p\n", (void*)iBaseDiff);\r
 245         // Adjust Dynamic Table\r
 246         dynamicTab = PTR( (uintptr_t)dynamicTab + iBaseDiff);\r
 247         LOG("dynamicTab = %p\n", dynamicTab);\r
 248 \r
 249         hdr->entrypoint += iBaseDiff;\r
 250         \r
 251         hdr->misc.SymTable = 0;\r
 252         hdr->misc.HashTable = 0;\r
 253         \r
 254         // === Get Symbol table and String Table ===\r
 255         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
 256         {\r
 257                 switch(dynamicTab[j].d_tag)\r
 258                 {\r
 259                 // --- Symbol Table ---\r
 260                 case DT_SYMTAB:\r
 261                         dynamicTab[j].d_val += iBaseDiff;\r
 262                         dynsymtab = PTRMK(void, dynamicTab[j].d_val);\r
 263                         hdr->misc.SymTable = dynamicTab[j].d_val;       // Saved in unused bytes of ident\r
 264                         break;\r
 265                 \r
 266                 // --- String Table ---\r
 267                 case DT_STRTAB:\r
 268                         dynamicTab[j].d_val += iBaseDiff;\r
 269                         dynstrtab = PTRMK(void, dynamicTab[j].d_val);\r
 270                         break;\r
 271                 \r
 272                 // --- Hash Table --\r
 273                 case DT_HASH:\r
 274                         dynamicTab[j].d_val += iBaseDiff;\r
 275                         iSymCount = (PTRMK(uint32_t, dynamicTab[j].d_val))[1];\r
 276                         hdr->misc.HashTable = dynamicTab[j].d_val;      // Saved in unused bytes of ident\r
 277                         break;\r
 278                 }\r
 279         }\r
 280         \r
 281         LOG("hdr->misc.SymTable = %x, hdr->misc.HashTable = %x",\r
 282                 hdr->misc.SymTable, hdr->misc.HashTable);\r
 283 \r
 284 \r
 285         // Alter Symbols to true base\r
 286         for(i = 0; i < iSymCount; i ++)\r
 287         {\r
 288                 dynsymtab[i].nameOfs += (uintptr_t)dynstrtab;\r
 289                 if( dynsymtab[i].shndx == SHN_UNDEF )\r
 290                 {\r
 291                         LOG("Sym '%s' = UNDEF\n", MKPTR(char,dynsymtab[i].name));\r
 292                 }\r
 293                 else\r
 294                 {\r
 295                         dynsymtab[i].value += iBaseDiff;\r
 296                         LOG("Sym '%s' = 0x%x (relocated)\n", MKPTR(char,dynsymtab[i].name), dynsymtab[i].value);\r
 297                 }\r
 298         }\r
 299         \r
 300         // === Add to loaded list (can be imported now) ===\r
 301         Binary_SetReadyToUse( Base );\r
 302 \r
 303         // === Parse Relocation Data ===\r
 304         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
 305         {\r
 306                 switch(dynamicTab[j].d_tag)\r
 307                 {\r
 308                 // --- Shared Library Name ---\r
 309                 case DT_SONAME:\r
 310                         LOG(".so Name '%s'\n", dynstrtab + dynamicTab[j].d_val);\r
 311                         break;\r
 312                 // --- Needed Library ---\r
 313                 case DT_NEEDED:\r
 314                         libPath = dynstrtab + dynamicTab[j].d_val;\r
 315                         Binary_LoadLibrary(libPath);\r
 316                         break;\r
 317                 // --- PLT/GOT ---\r
 318                 case DT_PLTGOT: pltgot = (void*)(iBaseDiff+dynamicTab[j].d_val);        break;\r
 319                 case DT_JMPREL: plt = (void*)(iBaseDiff+dynamicTab[j].d_val);   break;\r
 320                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;\r
 321                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;\r
 322                 \r
 323                 // --- Relocation ---\r
 324                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;\r
 325                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;\r
 326                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;\r
 327                 \r
 328                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;\r
 329                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;\r
 330                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;\r
 331                 }\r
 332         }\r
 333         \r
 334         // Parse Relocation Entries\r
 335         if(rel && relSz)\r
 336         {\r
 337                 j = relSz / relEntSz;\r
 338                 for( i = 0; i < j; i++ )\r
 339                 {\r
 340                         ptr = (void*)(iBaseDiff + rel[i].r_offset);\r
 341                         if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
 342                                 bFailed = 1;\r
 343                         }\r
 344                 }\r
 345         }\r
 346         // Parse Relocation Entries\r
 347         if(rela && relaSz)\r
 348         {\r
 349                 j = relaSz / relaEntSz;\r
 350                 for( i = 0; i < j; i++ )\r
 351                 {\r
 352                         ptr = (void*)(iBaseDiff + rela[i].r_offset);\r
 353                         if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab, Base) ) {\r
 354                                 bFailed = 1;\r
 355                         }\r
 356                 }\r
 357         }\r
 358         \r
 359         // === Process PLT (Procedure Linkage Table) ===\r
 360         if(plt && pltSz)\r
 361         {\r
 362                 if(pltType == DT_REL)\r
 363                 {\r
 364                         Elf32_Rel       *pltRel = plt;\r
 365                         j = pltSz / sizeof(Elf32_Rel);\r
 366                         LOG("PLT Rel - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
 367                         for(i = 0; i < j; i++)\r
 368                         {\r
 369                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);\r
 370                                 if( !Elf_Int_DoRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
 371                                         bFailed = 1;\r
 372                                 }\r
 373                         }\r
 374                 }\r
 375                 else\r
 376                 {\r
 377                         Elf32_Rela      *pltRela = plt;\r
 378                         j = pltSz / sizeof(Elf32_Rela);\r
 379                         LOG("PLT RelA - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
 380                         for(i=0;i<j;i++)\r
 381                         {\r
 382                                 ptr = (void*)(iBaseDiff + pltRela[i].r_offset);\r
 383                                 if( !Elf_Int_DoRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab, Base) ) {\r
 384                                         bFailed = 1;\r
 385                                 }\r
 386                         }\r
 387                 }\r
 388         }\r
 389         \r
 390         if(bFailed) {\r
 391                 LEAVE('i', 0);\r
 392                 return 0;\r
 393         }\r
 394         \r
 395         LEAVE('x', hdr->entrypoint);\r
 396         return hdr->entrypoint;\r
 397 }\r
 398 \r
 399 /**\r
 400  * \fn void Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
 401  * \brief Performs a relocation\r
 402  * \param r_info        Field from relocation entry\r
 403  * \param ptr   Pointer to location of relocation\r
 404  * \param addend        Value to add to symbol\r
 405  * \param symtab        Symbol Table\r
 406  * \param base  Base of loaded binary\r
 407  */\r
 408 int Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
 409 {\r
 410         uintptr_t       val;\r
 411          int    type = ELF32_R_TYPE(r_info);\r
 412          int    sym = ELF32_R_SYM(r_info);\r
 413         char    *sSymName = PTRMK(char, symtab[sym].name);\r
 414         \r
 415         //LogF("Elf_Int_DoRelocate: (r_info=0x%x, ptr=0x%x, addend=0x%x, .., base=0x%x)\n",\r
 416         //      r_info, ptr, addend, base);\r
 417         \r
 418         switch( type )\r
 419         {\r
 420         // Standard 32 Bit Relocation (S+A)\r
 421         case R_386_32:\r
 422                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 423                         Warning("Unable to find symbol '%s'", sSymName);\r
 424                         return 0;\r
 425                 }\r
 426                 LOG("%08x R_386_32 *%p += %p('%s')\n", r_info, ptr, (void*)val, sSymName);\r
 427                 *ptr = val + addend;\r
 428                 break;\r
 429                 \r
 430         // 32 Bit Relocation wrt. Offset (S+A-P)\r
 431         case R_386_PC32:\r
 432                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 433                         Warning("Unable to find symbol '%s'", sSymName);\r
 434                         return 0;\r
 435                 }\r
 436                 LOG("%08x R_386_PC32 *%p = 0x%x + %p('%s') - %p\n", r_info, ptr, *ptr, (void*)val, sSymName, ptr );\r
 437                 // TODO: Check if it needs the true value of ptr or the compiled value\r
 438                 // NOTE: Testing using true value\r
 439                 *ptr = val + addend - (uintptr_t)ptr;\r
 440                 break;\r
 441 \r
 442         // Absolute Value of a symbol (S)\r
 443         case R_386_GLOB_DAT:\r
 444                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 445                         Warning("Unable to find symbol '%s'", sSymName);\r
 446                         return 0; \r
 447                 }\r
 448                 LOG("%08x R_386_GLOB_DAT *%p = 0x%x(%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
 449                 *ptr = val;\r
 450                 break;\r
 451         \r
 452         // Absolute Value of a symbol (S)\r
 453         case R_386_JMP_SLOT:\r
 454                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 455                         Warning("Unable to find symbol '%s'", sSymName);\r
 456                         return 0;\r
 457                 }\r
 458                 LOG("%08x R_386_JMP_SLOT *%p = 0x%x (%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
 459                 *ptr = val;\r
 460                 break;\r
 461 \r
 462         // Base Address (B+A)\r
 463         case R_386_RELATIVE:\r
 464                 LOG("%08x R_386_RELATIVE *%p = %p + 0x%x\n", r_info, ptr, base, addend);\r
 465                 *ptr = (uintptr_t)base + addend;\r
 466                 break;\r
 467                 \r
 468         default:\r
 469                 LOG("Rel %p: 0x%x,%i\n", ptr, sym, type);\r
 470                 break;\r
 471         }\r
 472         return 1;\r
 473 }\r
 474 \r
 475 /**\r
 476  * \fn int Elf_GetSymbol(void *Base, char *name, uintptr_t *ret)\r
 477  * \brief Get a symbol from the loaded binary\r
 478  */\r
 479 int Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret)\r
 480 {\r
 481         Elf32_Ehdr      *hdr = (void*)Base;\r
 482         Elf32_Sym       *symtab;\r
 483          int    nbuckets = 0;\r
 484          int    iSymCount = 0;\r
 485          int    i;\r
 486         uint32_t        *pBuckets;\r
 487         uint32_t        *pChains;\r
 488         uint32_t        iNameHash;\r
 489 \r
 490         if(!Base)       return 0;\r
 491 \r
 492         pBuckets = PTR(hdr->misc.HashTable);\r
 493         symtab = PTR(hdr->misc.SymTable);\r
 494         \r
 495 //      LOG("Base = %p : pBuckets = %p, symtab = %p\n", Base, pBuckets, symtab);\r
 496         \r
 497         if(!pBuckets || !symtab)\r
 498                 return 0;\r
 499         \r
 500         nbuckets = pBuckets[0];\r
 501         iSymCount = pBuckets[1];\r
 502         pBuckets = &pBuckets[2];\r
 503         pChains = &pBuckets[ nbuckets ];\r
 504         \r
 505         // Get hash\r
 506         iNameHash = Elf_Int_HashString(Name);\r
 507         iNameHash %= nbuckets;\r
 508 \r
 509         // Check Bucket\r
 510         i = pBuckets[ iNameHash ];\r
 511         if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
 512                 if(ret) *ret = symtab[ i ].value;\r
 513                 return 1;\r
 514         }\r
 515         \r
 516         // Walk Chain\r
 517         while(pChains[i] != STN_UNDEF)\r
 518         {\r
 519                 i = pChains[i];\r
 520                 if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
 521                         if(ret) *ret = symtab[ i ].value;\r
 522                         return 1;\r
 523                 }\r
 524         }\r
 525         return 0;\r
 526 }\r
 527 \r
 528 /**\r
 529  * \fn uint32_t Elf_Int_HashString(char *str)\r
 530  * \brief Hash a string in the ELF format\r
 531  * \param str   String to hash\r
 532  * \return Hash value\r
 533  */\r
 534 uint32_t Elf_Int_HashString(char *str)\r
 535 {\r
 536         uint32_t        h = 0, g;\r
 537         while(*str)\r
 538         {\r
 539                 h = (h << 4) + *str++;\r
 540                 if( (g = h & 0xf0000000) )\r
 541                         h ^= g >> 24;\r
 542                 h &= ~g;\r
 543         }\r
 544         return h;\r
 545 }\r