Usermode/Libraries/ld-acess.so_src/elf.c

   1 /*
   2  * AcessOS 1 - Dynamic Loader
   3  * By thePowersGang
   4  */
   5 #include "common.h"
   6 #include <stdint.h>
   7 #include "elf32.h"
   8 #include "elf64.h"
   9
  10 #define DEBUG   1
  11
  12 #if DEBUG
  13 # define        DEBUGS(v...)    SysDebug("ld-acess - " v)
  14 #else
  15 # define        DEBUGS(...)
  16 #endif
  17
  18 // === CONSTANTS ===
  19 #if DEBUG
  20 //static const char     *csaDT_NAMES[] = {"DT_NULL", "DT_NEEDED", "DT_PLTRELSZ", "DT_PLTGOT", "DT_HASH", "DT_STRTAB", "DT_SYMTAB", "DT_RELA", "DT_RELASZ", "DT_RELAENT", "DT_STRSZ", "DT_SYMENT", "DT_INIT", "DT_FINI", "DT_SONAME", "DT_RPATH", "DT_SYMBOLIC", "DT_REL", "DT_RELSZ", "DT_RELENT", "DT_PLTREL", "DT_DEBUG", "DT_TEXTREL", "DT_JMPREL"};
  21 static const char       *csaR_NAMES[] = {"R_386_NONE", "R_386_32", "R_386_PC32", "R_386_GOT32", "R_386_PLT32", "R_386_COPY", "R_386_GLOB_DAT", "R_386_JMP_SLOT", "R_386_RELATIVE", "R_386_GOTOFF", "R_386_GOTPC", "R_386_LAST"};
  22 #endif
  23
  24 // === PROTOTYPES ===
  25 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  26 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  27 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  28 Uint32  ElfHashString(const char *name);
  29
  30 // === CODE ===
  31 /**
  32  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  33  * \brief Relocates a loaded ELF Executable
  34  */
  35 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  36 {
  37         Elf32_Ehdr      *hdr = Base;
  38
  39         switch(hdr->e_ident[4])
  40         {
  41         case ELFCLASS32:
  42                 return Elf32Relocate(Base, envp, Filename);
  43         case ELFCLASS64:
  44                 return Elf64Relocate(Base, envp, Filename);
  45         default:
  46                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  47                 return NULL;
  48         }
  49 }
  50
  51 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
  52 {
  53          int    i;
  54         Elf64_Ehdr      *hdr = Base;
  55         Elf64_Phdr      *phtab;
  56         Elf64_Dyn       *dyntab;
  57         Elf64_Addr      compiledBase = -1, baseDiff;
  58         Elf64_Sym       *symtab = NULL;
  59         char    *strtab = NULL;
  60         Elf64_Word      *hashtab = NULL;
  61         Elf64_Rel       *rel = NULL;
  62          int    rel_count = 0;
  63         Elf64_Rela      *rela = NULL;
  64          int    rela_count = 0;
  65         void    *pltrel = NULL;
  66          int    plt_size = 0, plt_type = 0;
  67
  68         DEBUGS("Elf64Relocate: e_ident = '%.16s'", hdr->e_ident);
  69         DEBUGS("Elf64Relocate: e_phoff = %i, e_phnum = %i",
  70                 hdr->e_phoff, hdr->e_phnum);
  71
  72         // Scan for the dynamic table (and find the compiled base)
  73         phtab = Base + hdr->e_phoff;
  74         for( i = 0; i < hdr->e_phnum; i ++ )
  75         {
  76                 if(phtab[i].p_type == PT_DYNAMIC)
  77                         dyntab = (void *)phtab[i].p_vaddr;
  78                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
  79                         compiledBase = phtab[i].p_vaddr;
  80         }
  81
  82         baseDiff = (Elf64_Addr)Base - compiledBase;
  83
  84         DEBUGS("baseDiff = %p", baseDiff);
  85
  86         if(dyntab == NULL) {
  87                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
  88                 return (void *)(hdr->e_entry + baseDiff);
  89         }
  90
  91         dyntab = (void *)((Elf64_Addr)dyntab + baseDiff);
  92
  93         // Parse the dynamic table (first pass)
  94         // - Search for String, Symbol and Hash tables
  95         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
  96         {
  97                 switch(dyntab[i].d_tag)
  98                 {
  99                 case DT_SYMTAB:
 100                         dyntab[i].d_un.d_ptr += baseDiff;
 101                         symtab = (void *)dyntab[i].d_un.d_ptr;
 102                         break;
 103                 case DT_STRTAB:
 104                         dyntab[i].d_un.d_ptr += baseDiff;
 105                         strtab = (void *)dyntab[i].d_un.d_ptr;
 106                         break;
 107                 case DT_HASH:
 108                         dyntab[i].d_un.d_ptr += baseDiff;
 109                         hashtab = (void *)dyntab[i].d_un.d_ptr;
 110                         break;
 111                 }
 112         }
 113
 114         if( !symtab || !strtab || !hashtab ) {
 115                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 116                 return NULL;
 117         }
 118
 119         // Ready for symbol use
 120         AddLoaded( Filename, Base );
 121
 122         // Second pass on dynamic table
 123         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 124         {
 125                 switch(dyntab[i].d_tag)
 126                 {
 127                 case DT_SONAME: break;
 128
 129                 case DT_NEEDED: {
 130                         char *libPath = strtab + dyntab[i].d_un.d_val;
 131                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 132                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 133                                 return NULL;
 134                         }
 135                         } break;
 136
 137                 // Relocation entries
 138                 case DT_REL:
 139                         dyntab[i].d_un.d_ptr += baseDiff;
 140                         rel = (void *)dyntab[i].d_un.d_ptr;
 141                         break;
 142                 case DT_RELSZ:
 143                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 144                         break;
 145                 case DT_RELENT:
 146                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 147                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 148                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 149                                 return NULL;
 150                         }
 151                         break;
 152                 case DT_RELA:
 153                         dyntab[i].d_un.d_ptr += baseDiff;
 154                         rela = (void *)dyntab[i].d_un.d_ptr;
 155                         break;
 156                 case DT_RELASZ:
 157                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 158                         break;
 159                 case DT_RELAENT:
 160                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 161                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 162                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 163                                 return NULL;
 164                         }
 165                         break;
 166                 case DT_JMPREL:
 167                         dyntab[i].d_un.d_ptr += baseDiff;
 168                         pltrel = (void *)dyntab[i].d_un.d_ptr;
 169                         break;
 170                 case DT_PLTREL:
 171                         plt_type = dyntab[i].d_un.d_val;
 172                         break;
 173                 case DT_PLTRELSZ:
 174                         plt_size = dyntab[i].d_un.d_val;
 175                         break;
 176                 }
 177         }
 178
 179         // Relocation function
 180         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 181         {
 182                  int    sym = ELF64_R_SYM(r_info);
 183                  int    type = ELF64_R_TYPE(r_info);
 184                 const char      *symname = strtab + symtab[sym].st_name;
 185                 switch( type )
 186                 {
 187                 case R_X86_64_NONE:
 188                         break;
 189                 case R_X86_64_64:
 190                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname) + addend;
 191                         break;
 192                 default:
 193                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 194                 }
 195         }
 196
 197         if( rel )
 198         {
 199                 for( i = 0; i < rel_count; i ++ )
 200                 {
 201                         uint64_t *ptr = (void *)( rel[i].r_offset + baseDiff );
 202                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 203                 }
 204         }
 205
 206         if( rela )
 207         {
 208                 for( i = 0; i < rela_count; i ++ )
 209                 {
 210                         _Elf64DoReloc( rela[i].r_info, (void *)( rela[i].r_offset + baseDiff ), rela[i].r_addend );
 211                 }
 212         }
 213
 214         if( pltrel && plt_type )
 215         {
 216                 if( plt_type == DT_REL ) {
 217                         Elf64_Rel       *plt = pltrel;
 218                          int    count = plt_size / sizeof(Elf64_Rel);
 219                         for( i = 0; i < count; i ++ )
 220                         {
 221                                 uint64_t *ptr = (void *)( plt[i].r_offset + baseDiff );
 222                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 223                         }
 224                 }
 225                 else {
 226                         Elf64_Rela      *plt = pltrel;
 227                          int    count = plt_size / sizeof(Elf64_Rela);
 228                         for( i = 0; i < count; i ++ )
 229                         {
 230                                 _Elf64DoReloc( plt[i].r_info, (void *)(plt[i].r_offset + baseDiff), plt[i].r_addend);
 231                         }
 232                 }
 233         }
 234
 235         return (void *)(hdr->e_entry + baseDiff);
 236 }
 237
 238 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 239 {
 240         Elf32_Ehdr      *hdr = Base;
 241         Elf32_Phdr      *phtab;
 242          int    i, j;   // Counters
 243         char    *libPath;
 244         Uint    iRealBase = -1;
 245         Uint    iBaseDiff;
 246          int    iSegmentCount;
 247          int    iSymCount;
 248         Elf32_Rel       *rel = NULL;
 249         Elf32_Rela      *rela = NULL;
 250         Uint32  *pltgot = NULL;
 251         void    *plt = NULL;
 252          int    relSz=0, relEntSz=8;
 253          int    relaSz=0, relaEntSz=8;
 254          int    pltSz=0, pltType=0;
 255         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 256         char    *dynstrtab = NULL;      // .dynamic String Table
 257         Elf32_Sym       *dynsymtab;
 258
 259         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 260
 261         // Check magic header
 262
 263
 264         // Parse Program Header to get Dynamic Table
 265         phtab = Base + hdr->phoff;
 266         iSegmentCount = hdr->phentcount;
 267         for(i=0;i<iSegmentCount;i++)
 268         {
 269                 // Determine linked base address
 270                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 271                         iRealBase = phtab[i].VAddr;
 272
 273                 // Find Dynamic Section
 274                 if(phtab[i].Type == PT_DYNAMIC) {
 275                         if(dynamicTab) {
 276                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 277                                 continue;
 278                         }
 279                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 280                         j = i;  // Save Dynamic Table ID
 281                 }
 282         }
 283
 284         // Page Align real base
 285         iRealBase &= ~0xFFF;
 286         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 287
 288         // Adjust "Real" Base
 289         iBaseDiff = (intptr_t)Base - iRealBase;
 290
 291 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 292
 293         // Check if a PT_DYNAMIC segement was found
 294         if(!dynamicTab) {
 295                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 296                 return (void *)hdr->entrypoint + iBaseDiff;
 297         }
 298
 299         // Adjust Dynamic Table
 300         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 301
 302         // === Get Symbol table and String Table ===
 303         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 304         {
 305                 switch(dynamicTab[j].d_tag)
 306                 {
 307                 // --- Symbol Table ---
 308                 case DT_SYMTAB:
 309                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 310                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 311                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 312                         dynsymtab = (void*)(dynamicTab[j].d_val);
 313 //                      hdr->misc.SymTable = dynamicTab[j].d_val;       // Saved in unused bytes of ident
 314                         break;
 315                 // --- String Table ---
 316                 case DT_STRTAB:
 317                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 318                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 319                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 320                         dynstrtab = (void*)(dynamicTab[j].d_val);
 321                         break;
 322                 // --- Hash Table --
 323                 case DT_HASH:
 324                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 325                         iSymCount = ((Uint*)(dynamicTab[j].d_val))[1];
 326 //                      hdr->misc.HashTable = dynamicTab[j].d_val;      // Saved in unused bytes of ident
 327                         break;
 328                 }
 329         }
 330
 331         if(dynsymtab == NULL) {
 332                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 333                 return (void *) hdr->entrypoint + iBaseDiff;
 334         }
 335
 336         #if 0
 337         // Alter Symbols to true base
 338         for(i=0;i<iSymCount;i++)
 339         {
 340                 dynsymtab[i].value += iBaseDiff;
 341                 dynsymtab[i].nameOfs += (intptr_t)dynstrtab;
 342                 //DEBUGS("elf_relocate: Sym '%s' = 0x%x (relocated)", dynsymtab[i].name, dynsymtab[i].value);
 343         }
 344         #endif
 345
 346         // === Add to loaded list (can be imported now) ===
 347         AddLoaded( Filename, Base );
 348
 349         // === Parse Relocation Data ===
 350         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 351         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 352         {
 353                 switch(dynamicTab[j].d_tag)
 354                 {
 355                 // --- Shared Library Name ---
 356                 case DT_SONAME:
 357                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 358                         break;
 359                 // --- Needed Library ---
 360                 case DT_NEEDED:
 361                         libPath = dynstrtab + dynamicTab[j].d_val;
 362                         DEBUGS(" Required Library '%s'", libPath);
 363                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 364                                 #if DEBUG
 365                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 366                                 #else
 367                                 SysDebug("Unable to load required library '%s'", libPath);
 368                                 #endif
 369                                 return 0;
 370                         }
 371                         break;
 372                 // --- PLT/GOT ---
 373                 case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 374                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 375                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 376                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 377
 378                 // --- Relocation ---
 379                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 380                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 381                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 382                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 383                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 384                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 385
 386                 // --- Symbol Table ---
 387                 case DT_SYMTAB:
 388                 // --- Hash Table ---
 389                 case DT_HASH:
 390                 // --- String Table ---
 391                 case DT_STRTAB:
 392                         break;
 393
 394                 // --- Unknown ---
 395                 default:
 396                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 397                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 398                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 399                         break;
 400                 }
 401         }
 402
 403         DEBUGS(" elf_relocate: Beginning Relocation");
 404
 405         void elf_doRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab)
 406         {
 407                  int    type = ELF32_R_TYPE(r_info);
 408                  int    sym = ELF32_R_SYM(r_info);
 409                 Uint32  val;
 410                 const char      *symname = dynstrtab + symtab[sym].nameOfs;
 411                 switch( type )
 412                 {
 413                 // Standard 32 Bit Relocation (S+A)
 414                 case R_386_32:
 415                         val = (intptr_t) GetSymbol( symname );
 416                         DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
 417                                         ptr, val, symname);
 418                         *ptr = val + addend;
 419                         break;
 420
 421                 // 32 Bit Relocation wrt. Offset (S+A-P)
 422                 case R_386_PC32:
 423                         DEBUGS(" elf_doRelocate: #%i: '%s'", sym, symname);
 424                         val = (intptr_t) GetSymbol( symname );
 425                         DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
 426                                 ptr, *ptr, val, (intptr_t)ptr );
 427                         *ptr = val + addend - (intptr_t)ptr;
 428                         //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 429                         break;
 430
 431                 // Absolute Value of a symbol (S)
 432                 case R_386_GLOB_DAT:
 433                 case R_386_JMP_SLOT:
 434                         DEBUGS(" elf_doRelocate: #%i: '%s'", sym, symname);
 435                         val = (intptr_t) GetSymbol( symname );
 436                         DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
 437                         *ptr = val;
 438                         break;
 439
 440                 // Base Address (B+A)
 441                 case R_386_RELATIVE:
 442                         DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 443                         *ptr = iBaseDiff + addend;
 444                         break;
 445
 446                 default:
 447                         DEBUGS(" elf_doRelocate: Rel 0x%x: 0x%x,%s", ptr, sym, csaR_NAMES[type]);
 448                         break;
 449                 }
 450         }
 451
 452         // Parse Relocation Entries
 453         if(rel && relSz)
 454         {
 455                 Uint32  *ptr;
 456                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 457                 j = relSz / relEntSz;
 458                 for( i = 0; i < j; i++ )
 459                 {
 460                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 461                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 462                         elf_doRelocate(rel[i].r_info, ptr, *ptr, dynsymtab);
 463                 }
 464         }
 465         // Parse Relocation Entries
 466         if(rela && relaSz)
 467         {
 468                 Uint32  *ptr;
 469                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 470                 j = relaSz / relaEntSz;
 471                 for( i = 0; i < j; i++ )
 472                 {
 473                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 474                         elf_doRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab);
 475                 }
 476         }
 477
 478         // === Process PLT (Procedure Linkage Table) ===
 479         if(plt && pltSz)
 480         {
 481                 Uint32  *ptr;
 482                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 483                 if(pltType == DT_REL)
 484                 {
 485                         Elf32_Rel       *pltRel = plt;
 486                         j = pltSz / sizeof(Elf32_Rel);
 487                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 488                         for(i=0;i<j;i++)
 489                         {
 490                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 491                                 elf_doRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab);
 492                         }
 493                 }
 494                 else
 495                 {
 496                         Elf32_Rela      *pltRela = plt;
 497                         j = pltSz / sizeof(Elf32_Rela);
 498                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 499                         for(i=0;i<j;i++)
 500                         {
 501                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 502                                 elf_doRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab);
 503                         }
 504                 }
 505         }
 506
 507         DEBUGS("ElfRelocate: RETURN 0x%x", hdr->entrypoint + iBaseDiff);
 508         return (void*)hdr->entrypoint + iBaseDiff;
 509 }
 510
 511
 512 /**
 513  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
 514  */
 515 int ElfGetSymbol(void *Base, const char *Name, void **ret)
 516 {
 517         Elf32_Ehdr      *hdr = Base;
 518         Elf32_Sym       *symtab;
 519          int    nbuckets = 0;
 520          int    iSymCount = 0;
 521          int    i;
 522         Uint32  *pBuckets;
 523         Uint32  *pChains;
 524         Uint    iNameHash;
 525         const char      *dynstrtab;
 526         uintptr_t       iBaseDiff = -1;
 527
 528         //DEBUGS("ElfGetSymbol: (Base=0x%x, Name='%s')", Base, Name);
 529         #if 0
 530         pBuckets = (void *) (intptr_t) hdr->misc.HashTable;
 531         symtab = (void *) (intptr_t) hdr->misc.SymTable;
 532         dynstrtab = (void *) (intptr_t) hdr->misc.StrTab;
 533         #else
 534         dynstrtab = NULL;
 535         pBuckets = NULL;
 536         symtab = NULL;
 537         #endif
 538
 539         // Catch the current executable
 540         if( !pBuckets )
 541         {
 542                 Elf32_Phdr      *phtab;
 543                 Elf32_Dyn       *dynTab = NULL;
 544                  int    j;
 545
 546                 // Locate the tables
 547                 phtab = (void*)( Base + hdr->phoff );
 548                 for( i = 0; i < hdr->phentcount; i ++ )
 549                 {
 550                         if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 551                                 iBaseDiff = phtab[i].VAddr;
 552                         if( phtab[i].Type == PT_DYNAMIC ) {
 553                                 dynTab = (void*)(intptr_t)phtab[i].VAddr;
 554                         }
 555                 }
 556                 if( !dynTab ) {
 557                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p");
 558                         return 0;
 559                 }
 560                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 561                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 562
 563                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 564                 {
 565                         switch(dynTab[j].d_tag)
 566                         {
 567                         // --- Symbol Table ---
 568                         case DT_SYMTAB:
 569                                 symtab = (void*)(intptr_t) dynTab[j].d_val;     // Rebased in Relocate
 570                                 break;
 571                         case DT_STRTAB:
 572                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_val;
 573                                 break;
 574                         // --- Hash Table --
 575                         case DT_HASH:
 576                                 pBuckets = (void*)(intptr_t) dynTab[j].d_val;
 577                                 break;
 578                         }
 579                 }
 580
 581                 #if 0
 582                 hdr->misc.HashTable = pBucktets;
 583                 hdr->misc.SymTable = symtab;
 584                 hdr->misc.StrTab = dynstrtab;
 585                 #endif
 586         }
 587
 588         nbuckets = pBuckets[0];
 589         iSymCount = pBuckets[1];
 590         pBuckets = &pBuckets[2];
 591         pChains = &pBuckets[ nbuckets ];
 592
 593         // Get hash
 594         iNameHash = ElfHashString(Name);
 595         iNameHash %= nbuckets;
 596         //DEBUGS(" ElfGetSymbol: iNameHash = 0x%x", iNameHash);
 597
 598         // Walk Chain
 599         i = pBuckets[ iNameHash ];
 600         //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")", symtab[i].name);
 601         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 602                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 603                 return 1;
 604         }
 605
 606         //DEBUGS(" ElfGetSymbol: Hash of first = 0x%x", ElfHashString( symtab[i].name ) % nbuckets);
 607         while(pChains[i] != STN_UNDEF)
 608         {
 609                 //DEBUGS(" pChains[%i] = %i", i, pChains[i]);
 610                 i = pChains[i];
 611                 //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")", symtab[ i ].name);
 612                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 613                         //DEBUGS("ElfGetSymbol: RETURN 1, '%s' = 0x%x", symtab[ i ].name, symtab[ i ].value);
 614                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 615                         return 1;
 616                 }
 617         }
 618
 619         //DEBUGS("ElfGetSymbol: RETURN 0, Symbol '%s' not found", Name);
 620         return 0;
 621 }
 622
 623 Uint32 ElfHashString(const char *name)
 624 {
 625         Uint32  h = 0, g;
 626         while(*name)
 627         {
 628                 h = (h << 4) + *(Uint8*)name++;
 629                 if( (g = h & 0xf0000000) )
 630                         h ^= g >> 24;
 631                 h &= ~g;
 632         }
 633         return h;
 634 }
 635
 636 #if 0
 637 unsigned long elf_hash(const unsigned char *name)
 638 {
 639         unsigned long   h = 0, g;
 640         while (*name)
 641         {
 642                 h = (h << 4) + *name++;
 643                 if (g = h & 0xf0000000)
 644                         h ^= g >> 24;
 645                 h &= ~g;
 646         }
 647         return h;
 648 }
 649 #endif