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(FILE *FP);\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(FILE *FP)\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("pFP", FP);\r
  50         \r
  51         // Read ELF Header\r
  52         fread(&hdr, sizeof(hdr), 1, FP);\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         fseek(FP, hdr.phoff, SEEK_SET);\r
  78         fread(phtab, sizeof(Elf32_Phdr), hdr.phentcount, FP);\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 > max )\r
 112                         max = phtab[i].VAddr;\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                         fseek(FP, phtab[i].Offset, SEEK_SET);\r
 147                         fread(tmp, phtab[i].FileSize, 1, FP);\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                 fseek(FP, phtab[i].Offset, SEEK_SET);\r
 169                 fread( PTRMK(void, addr), phtab[i].FileSize, 1, FP );\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         // === Get Symbol table and String Table ===\r
 252         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
 253         {\r
 254                 switch(dynamicTab[j].d_tag)\r
 255                 {\r
 256                 // --- Symbol Table ---\r
 257                 case DT_SYMTAB:\r
 258                         dynamicTab[j].d_val += iBaseDiff;\r
 259                         dynsymtab = PTRMK(void, dynamicTab[j].d_val);\r
 260                         hdr->misc.SymTable = dynamicTab[j].d_val;       // Saved in unused bytes of ident\r
 261                         break;\r
 262                 \r
 263                 // --- String Table ---\r
 264                 case DT_STRTAB:\r
 265                         dynamicTab[j].d_val += iBaseDiff;\r
 266                         dynstrtab = PTRMK(void, dynamicTab[j].d_val);\r
 267                         break;\r
 268                 \r
 269                 // --- Hash Table --\r
 270                 case DT_HASH:\r
 271                         dynamicTab[j].d_val += iBaseDiff;\r
 272                         iSymCount = (PTRMK(uint32_t, dynamicTab[j].d_val))[1];\r
 273                         hdr->misc.HashTable = dynamicTab[j].d_val;      // Saved in unused bytes of ident\r
 274                         break;\r
 275                 }\r
 276         }\r
 277 \r
 278 \r
 279         // Alter Symbols to true base\r
 280         for(i = 0; i < iSymCount; i ++)\r
 281         {\r
 282                 dynsymtab[i].nameOfs += (uintptr_t)dynstrtab;\r
 283                 if( dynsymtab[i].shndx == SHN_UNDEF )\r
 284                 {\r
 285                         LOG("Sym '%s' = UNDEF\n", MKPTR(char,dynsymtab[i].name));\r
 286                 }\r
 287                 else\r
 288                 {\r
 289                         dynsymtab[i].value += iBaseDiff;\r
 290                         LOG("Sym '%s' = 0x%x (relocated)\n", MKPTR(char,dynsymtab[i].name), dynsymtab[i].value);\r
 291                 }\r
 292         }\r
 293         \r
 294         // === Add to loaded list (can be imported now) ===\r
 295         Binary_SetReadyToUse( Base );\r
 296 \r
 297         // === Parse Relocation Data ===\r
 298         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
 299         {\r
 300                 switch(dynamicTab[j].d_tag)\r
 301                 {\r
 302                 // --- Shared Library Name ---\r
 303                 case DT_SONAME:\r
 304                         LOG(".so Name '%s'\n", dynstrtab + dynamicTab[j].d_val);\r
 305                         break;\r
 306                 // --- Needed Library ---\r
 307                 case DT_NEEDED:\r
 308                         libPath = dynstrtab + dynamicTab[j].d_val;\r
 309                         Binary_LoadLibrary(libPath);\r
 310                         break;\r
 311                 // --- PLT/GOT ---\r
 312                 case DT_PLTGOT: pltgot = (void*)(iBaseDiff+dynamicTab[j].d_val);        break;\r
 313                 case DT_JMPREL: plt = (void*)(iBaseDiff+dynamicTab[j].d_val);   break;\r
 314                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;\r
 315                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;\r
 316                 \r
 317                 // --- Relocation ---\r
 318                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;\r
 319                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;\r
 320                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;\r
 321                 \r
 322                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;\r
 323                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;\r
 324                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;\r
 325                 }\r
 326         }\r
 327         \r
 328         // Parse Relocation Entries\r
 329         if(rel && relSz)\r
 330         {\r
 331                 j = relSz / relEntSz;\r
 332                 for( i = 0; i < j; i++ )\r
 333                 {\r
 334                         ptr = (void*)(iBaseDiff + rel[i].r_offset);\r
 335                         if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
 336                                 bFailed = 1;\r
 337                         }\r
 338                 }\r
 339         }\r
 340         // Parse Relocation Entries\r
 341         if(rela && relaSz)\r
 342         {\r
 343                 j = relaSz / relaEntSz;\r
 344                 for( i = 0; i < j; i++ )\r
 345                 {\r
 346                         ptr = (void*)(iBaseDiff + rela[i].r_offset);\r
 347                         if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab, Base) ) {\r
 348                                 bFailed = 1;\r
 349                         }\r
 350                 }\r
 351         }\r
 352         \r
 353         // === Process PLT (Procedure Linkage Table) ===\r
 354         if(plt && pltSz)\r
 355         {\r
 356                 if(pltType == DT_REL)\r
 357                 {\r
 358                         Elf32_Rel       *pltRel = plt;\r
 359                         j = pltSz / sizeof(Elf32_Rel);\r
 360                         LOG("PLT Rel - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
 361                         for(i = 0; i < j; i++)\r
 362                         {\r
 363                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);\r
 364                                 if( !Elf_Int_DoRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
 365                                         bFailed = 1;\r
 366                                 }\r
 367                         }\r
 368                 }\r
 369                 else\r
 370                 {\r
 371                         Elf32_Rela      *pltRela = plt;\r
 372                         j = pltSz / sizeof(Elf32_Rela);\r
 373                         LOG("PLT RelA - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
 374                         for(i=0;i<j;i++)\r
 375                         {\r
 376                                 ptr = (void*)(iBaseDiff + pltRela[i].r_offset);\r
 377                                 if( !Elf_Int_DoRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab, Base) ) {\r
 378                                         bFailed = 1;\r
 379                                 }\r
 380                         }\r
 381                 }\r
 382         }\r
 383         \r
 384         if(bFailed) {\r
 385                 LEAVE('i', 0);\r
 386                 return 0;\r
 387         }\r
 388         \r
 389         LEAVE('x', hdr->entrypoint);\r
 390         return hdr->entrypoint;\r
 391 }\r
 392 \r
 393 /**\r
 394  * \fn void Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
 395  * \brief Performs a relocation\r
 396  * \param r_info        Field from relocation entry\r
 397  * \param ptr   Pointer to location of relocation\r
 398  * \param addend        Value to add to symbol\r
 399  * \param symtab        Symbol Table\r
 400  * \param base  Base of loaded binary\r
 401  */\r
 402 int Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
 403 {\r
 404         uintptr_t       val;\r
 405          int    type = ELF32_R_TYPE(r_info);\r
 406          int    sym = ELF32_R_SYM(r_info);\r
 407         char    *sSymName = PTRMK(char, symtab[sym].name);\r
 408         \r
 409         //LogF("Elf_Int_DoRelocate: (r_info=0x%x, ptr=0x%x, addend=0x%x, .., base=0x%x)\n",\r
 410         //      r_info, ptr, addend, base);\r
 411         \r
 412         switch( type )\r
 413         {\r
 414         // Standard 32 Bit Relocation (S+A)\r
 415         case R_386_32:\r
 416                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 417                         Warning("Unable to find symbol '%s'", sSymName);\r
 418                         return 0;\r
 419                 }\r
 420                 LOG("%08x R_386_32 *%p += %p('%s')\n", r_info, ptr, (void*)val, sSymName);\r
 421                 *ptr = val + addend;\r
 422                 break;\r
 423                 \r
 424         // 32 Bit Relocation wrt. Offset (S+A-P)\r
 425         case R_386_PC32:\r
 426                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 427                         Warning("Unable to find symbol '%s'", sSymName);\r
 428                         return 0;\r
 429                 }\r
 430                 LOG("%08x R_386_PC32 *%p = 0x%x + %p('%s') - %p\n", r_info, ptr, *ptr, (void*)val, sSymName, ptr );\r
 431                 // TODO: Check if it needs the true value of ptr or the compiled value\r
 432                 // NOTE: Testing using true value\r
 433                 *ptr = val + addend - (uintptr_t)ptr;\r
 434                 break;\r
 435 \r
 436         // Absolute Value of a symbol (S)\r
 437         case R_386_GLOB_DAT:\r
 438                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 439                         Warning("Unable to find symbol '%s'", sSymName);\r
 440                         return 0; \r
 441                 }\r
 442                 LOG("%08x R_386_GLOB_DAT *%p = 0x%x(%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
 443                 *ptr = val;\r
 444                 break;\r
 445         \r
 446         // Absolute Value of a symbol (S)\r
 447         case R_386_JMP_SLOT:\r
 448                 if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
 449                         Warning("Unable to find symbol '%s'", sSymName);\r
 450                         return 0;\r
 451                 }\r
 452                 LOG("%08x R_386_JMP_SLOT *%p = 0x%x (%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
 453                 *ptr = val;\r
 454                 break;\r
 455 \r
 456         // Base Address (B+A)\r
 457         case R_386_RELATIVE:\r
 458                 LOG("%08x R_386_RELATIVE *%p = %p + 0x%x\n", r_info, ptr, base, addend);\r
 459                 *ptr = (uintptr_t)base + addend;\r
 460                 break;\r
 461                 \r
 462         default:\r
 463                 LOG("Rel %p: 0x%x,%i\n", ptr, sym, type);\r
 464                 break;\r
 465         }\r
 466         return 1;\r
 467 }\r
 468 \r
 469 /**\r
 470  * \fn int Elf_GetSymbol(void *Base, char *name, uintptr_t *ret)\r
 471  * \brief Get a symbol from the loaded binary\r
 472  */\r
 473 int Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret)\r
 474 {\r
 475         Elf32_Ehdr      *hdr = (void*)Base;\r
 476         Elf32_Sym       *symtab;\r
 477          int    nbuckets = 0;\r
 478          int    iSymCount = 0;\r
 479          int    i;\r
 480         uint32_t        *pBuckets;\r
 481         uint32_t        *pChains;\r
 482         uint32_t        iNameHash;\r
 483 \r
 484         if(!Base)       return 0;\r
 485 \r
 486         pBuckets = PTR(hdr->misc.HashTable);\r
 487         symtab = PTR(hdr->misc.SymTable);\r
 488         \r
 489         nbuckets = pBuckets[0];\r
 490         iSymCount = pBuckets[1];\r
 491         pBuckets = &pBuckets[2];\r
 492         pChains = &pBuckets[ nbuckets ];\r
 493         \r
 494         // Get hash\r
 495         iNameHash = Elf_Int_HashString(Name);\r
 496         iNameHash %= nbuckets;\r
 497 \r
 498         // Check Bucket\r
 499         i = pBuckets[ iNameHash ];\r
 500         if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
 501                 if(ret) *ret = symtab[ i ].value;\r
 502                 return 1;\r
 503         }\r
 504         \r
 505         // Walk Chain\r
 506         while(pChains[i] != STN_UNDEF)\r
 507         {\r
 508                 i = pChains[i];\r
 509                 if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
 510                         if(ret) *ret = symtab[ i ].value;\r
 511                         return 1;\r
 512                 }\r
 513         }\r
 514         return 0;\r
 515 }\r
 516 \r
 517 /**\r
 518  * \fn uint32_t Elf_Int_HashString(char *str)\r
 519  * \brief Hash a string in the ELF format\r
 520  * \param str   String to hash\r
 521  * \return Hash value\r
 522  */\r
 523 uint32_t Elf_Int_HashString(char *str)\r
 524 {\r
 525         uint32_t        h = 0, g;\r
 526         while(*str)\r
 527         {\r
 528                 h = (h << 4) + *str++;\r
 529                 if( (g = h & 0xf0000000) )\r
 530                         h ^= g >> 24;\r
 531                 h &= ~g;\r
 532         }\r
 533         return h;\r
 534 }\r