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: hdr = {");
  69         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
  70         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
  71         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
  72         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
  73         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
  74         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
  75         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
  76         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
  77         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
  78         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
  79         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
  80
  81         // Scan for the dynamic table (and find the compiled base)
  82         phtab = Base + hdr->e_phoff;
  83         for( i = 0; i < hdr->e_phnum; i ++ )
  84         {
  85                 if(phtab[i].p_type == PT_DYNAMIC)
  86                         dyntab = (void *)phtab[i].p_vaddr;
  87                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
  88                         compiledBase = phtab[i].p_vaddr;
  89         }
  90
  91         baseDiff = (Elf64_Addr)Base - compiledBase;
  92
  93         DEBUGS("baseDiff = %p", baseDiff);
  94
  95         if(dyntab == NULL) {
  96                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
  97                 return (void *)(hdr->e_entry + baseDiff);
  98         }
  99
 100         dyntab = (void *)((Elf64_Addr)dyntab + baseDiff);
 101
 102         // Parse the dynamic table (first pass)
 103         // - Search for String, Symbol and Hash tables
 104         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 105         {
 106                 switch(dyntab[i].d_tag)
 107                 {
 108                 case DT_SYMTAB:
 109                         dyntab[i].d_un.d_ptr += baseDiff;
 110                         symtab = (void *)dyntab[i].d_un.d_ptr;
 111                         break;
 112                 case DT_STRTAB:
 113                         dyntab[i].d_un.d_ptr += baseDiff;
 114                         strtab = (void *)dyntab[i].d_un.d_ptr;
 115                         break;
 116                 case DT_HASH:
 117                         dyntab[i].d_un.d_ptr += baseDiff;
 118                         hashtab = (void *)dyntab[i].d_un.d_ptr;
 119                         break;
 120                 }
 121         }
 122
 123         if( !symtab || !strtab || !hashtab ) {
 124                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 125                 return NULL;
 126         }
 127
 128         // Ready for symbol use
 129         AddLoaded( Filename, Base );
 130
 131         // Second pass on dynamic table
 132         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 133         {
 134                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 135                 switch(dyntab[i].d_tag)
 136                 {
 137                 case DT_SONAME: break;
 138
 139                 case DT_NEEDED: {
 140                         char *libPath = strtab + dyntab[i].d_un.d_val;
 141                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 142                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 143                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 144                                 return NULL;
 145                         }
 146                         } break;
 147
 148                 // Relocation entries
 149                 case DT_REL:
 150                         dyntab[i].d_un.d_ptr += baseDiff;
 151                         rel = (void *)dyntab[i].d_un.d_ptr;
 152                         break;
 153                 case DT_RELSZ:
 154                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 155                         break;
 156                 case DT_RELENT:
 157                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 158                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 159                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 160                                 return NULL;
 161                         }
 162                         break;
 163                 case DT_RELA:
 164                         dyntab[i].d_un.d_ptr += baseDiff;
 165                         rela = (void *)dyntab[i].d_un.d_ptr;
 166                         break;
 167                 case DT_RELASZ:
 168                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 169                         break;
 170                 case DT_RELAENT:
 171                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 172                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 173                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 174                                 return NULL;
 175                         }
 176                         break;
 177                 case DT_JMPREL:
 178                         dyntab[i].d_un.d_ptr += baseDiff;
 179                         pltrel = (void *)dyntab[i].d_un.d_ptr;
 180                         break;
 181                 case DT_PLTREL:
 182                         plt_type = dyntab[i].d_un.d_val;
 183                         break;
 184                 case DT_PLTRELSZ:
 185                         plt_size = dyntab[i].d_un.d_val;
 186                         break;
 187                 }
 188         }
 189
 190         // Relocation function
 191         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 192         {
 193                  int    sym = ELF64_R_SYM(r_info);
 194                  int    type = ELF64_R_TYPE(r_info);
 195                 const char      *symname = strtab + symtab[sym].st_name;
 196                 switch( type )
 197                 {
 198                 case R_X86_64_NONE:
 199                         break;
 200                 case R_X86_64_64:
 201                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname) + addend;
 202                         break;
 203                 default:
 204                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 205                         break;
 206                 }
 207         }
 208
 209         if( rel )
 210         {
 211                 DEBUGS("rel_count = %i", rel_count);
 212                 for( i = 0; i < rel_count; i ++ )
 213                 {
 214                         uint64_t *ptr = (void *)( rel[i].r_offset + baseDiff );
 215                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 216                 }
 217         }
 218
 219         if( rela )
 220         {
 221                 DEBUGS("rela_count = %i", rela_count);
 222                 for( i = 0; i < rela_count; i ++ )
 223                 {
 224                         _Elf64DoReloc( rela[i].r_info, (void *)( rela[i].r_offset + baseDiff ), rela[i].r_addend );
 225                 }
 226         }
 227
 228         if( pltrel && plt_type )
 229         {
 230                 if( plt_type == DT_REL ) {
 231                         Elf64_Rel       *plt = pltrel;
 232                          int    count = plt_size / sizeof(Elf64_Rel);
 233                         DEBUGS("plt rel count = %i", count);
 234                         for( i = 0; i < count; i ++ )
 235                         {
 236                                 uint64_t *ptr = (void *)( plt[i].r_offset + baseDiff );
 237                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 238                         }
 239                 }
 240                 else {
 241                         Elf64_Rela      *plt = pltrel;
 242                          int    count = plt_size / sizeof(Elf64_Rela);
 243                         DEBUGS("plt rela count = %i", count);
 244                         for( i = 0; i < count; i ++ )
 245                         {
 246                                 _Elf64DoReloc( plt[i].r_info, (void *)(plt[i].r_offset + baseDiff), plt[i].r_addend);
 247                         }
 248                 }
 249         }
 250
 251         DEBUGS("Elf64Relocate: Relocations done, return %p", (void *)(hdr->e_entry + baseDiff));
 252         return (void *)(hdr->e_entry + baseDiff);
 253 }
 254
 255 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 256 {
 257         Elf32_Ehdr      *hdr = Base;
 258         Elf32_Phdr      *phtab;
 259          int    i, j;   // Counters
 260         char    *libPath;
 261         Uint    iRealBase = -1;
 262         Uint    iBaseDiff;
 263          int    iSegmentCount;
 264          int    iSymCount;
 265         Elf32_Rel       *rel = NULL;
 266         Elf32_Rela      *rela = NULL;
 267         Uint32  *pltgot = NULL;
 268         void    *plt = NULL;
 269          int    relSz=0, relEntSz=8;
 270          int    relaSz=0, relaEntSz=8;
 271          int    pltSz=0, pltType=0;
 272         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 273         char    *dynstrtab = NULL;      // .dynamic String Table
 274         Elf32_Sym       *dynsymtab;
 275
 276         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 277
 278         // Check magic header
 279
 280
 281         // Parse Program Header to get Dynamic Table
 282         phtab = Base + hdr->phoff;
 283         iSegmentCount = hdr->phentcount;
 284         for(i=0;i<iSegmentCount;i++)
 285         {
 286                 // Determine linked base address
 287                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 288                         iRealBase = phtab[i].VAddr;
 289
 290                 // Find Dynamic Section
 291                 if(phtab[i].Type == PT_DYNAMIC) {
 292                         if(dynamicTab) {
 293                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 294                                 continue;
 295                         }
 296                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 297                         j = i;  // Save Dynamic Table ID
 298                 }
 299         }
 300
 301         // Page Align real base
 302         iRealBase &= ~0xFFF;
 303         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 304
 305         // Adjust "Real" Base
 306         iBaseDiff = (intptr_t)Base - iRealBase;
 307
 308 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 309
 310         // Check if a PT_DYNAMIC segement was found
 311         if(!dynamicTab) {
 312                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 313                 return (void *)hdr->entrypoint + iBaseDiff;
 314         }
 315
 316         // Adjust Dynamic Table
 317         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 318
 319         // === Get Symbol table and String Table ===
 320         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 321         {
 322                 switch(dynamicTab[j].d_tag)
 323                 {
 324                 // --- Symbol Table ---
 325                 case DT_SYMTAB:
 326                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 327                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 328                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 329                         dynsymtab = (void*)(dynamicTab[j].d_val);
 330 //                      hdr->misc.SymTable = dynamicTab[j].d_val;       // Saved in unused bytes of ident
 331                         break;
 332                 // --- String Table ---
 333                 case DT_STRTAB:
 334                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 335                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 336                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 337                         dynstrtab = (void*)(dynamicTab[j].d_val);
 338                         break;
 339                 // --- Hash Table --
 340                 case DT_HASH:
 341                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 342                         iSymCount = ((Uint*)(dynamicTab[j].d_val))[1];
 343 //                      hdr->misc.HashTable = dynamicTab[j].d_val;      // Saved in unused bytes of ident
 344                         break;
 345                 }
 346         }
 347
 348         if(dynsymtab == NULL) {
 349                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 350                 return (void *) hdr->entrypoint + iBaseDiff;
 351         }
 352
 353         #if 0
 354         // Alter Symbols to true base
 355         for(i=0;i<iSymCount;i++)
 356         {
 357                 dynsymtab[i].value += iBaseDiff;
 358                 dynsymtab[i].nameOfs += (intptr_t)dynstrtab;
 359                 //DEBUGS("elf_relocate: Sym '%s' = 0x%x (relocated)", dynsymtab[i].name, dynsymtab[i].value);
 360         }
 361         #endif
 362
 363         // === Add to loaded list (can be imported now) ===
 364         AddLoaded( Filename, Base );
 365
 366         // === Parse Relocation Data ===
 367         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 368         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 369         {
 370                 switch(dynamicTab[j].d_tag)
 371                 {
 372                 // --- Shared Library Name ---
 373                 case DT_SONAME:
 374                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 375                         break;
 376                 // --- Needed Library ---
 377                 case DT_NEEDED:
 378                         libPath = dynstrtab + dynamicTab[j].d_val;
 379                         DEBUGS(" Required Library '%s'", libPath);
 380                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 381                                 #if DEBUG
 382                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 383                                 #else
 384                                 SysDebug("Unable to load required library '%s'", libPath);
 385                                 #endif
 386                                 return 0;
 387                         }
 388                         break;
 389                 // --- PLT/GOT ---
 390                 case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 391                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 392                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 393                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 394
 395                 // --- Relocation ---
 396                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 397                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 398                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 399                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 400                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 401                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 402
 403                 // --- Symbol Table ---
 404                 case DT_SYMTAB:
 405                 // --- Hash Table ---
 406                 case DT_HASH:
 407                 // --- String Table ---
 408                 case DT_STRTAB:
 409                         break;
 410
 411                 // --- Unknown ---
 412                 default:
 413                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 414                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 415                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 416                         break;
 417                 }
 418         }
 419
 420         DEBUGS(" elf_relocate: Beginning Relocation");
 421
 422         void elf_doRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab)
 423         {
 424                  int    type = ELF32_R_TYPE(r_info);
 425                  int    sym = ELF32_R_SYM(r_info);
 426                 Uint32  val;
 427                 const char      *symname = dynstrtab + symtab[sym].nameOfs;
 428                 switch( type )
 429                 {
 430                 // Standard 32 Bit Relocation (S+A)
 431                 case R_386_32:
 432                         val = (intptr_t) GetSymbol( symname );
 433                         DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
 434                                         ptr, val, symname);
 435                         *ptr = val + addend;
 436                         break;
 437
 438                 // 32 Bit Relocation wrt. Offset (S+A-P)
 439                 case R_386_PC32:
 440                         DEBUGS(" elf_doRelocate: #%i: '%s'", sym, symname);
 441                         val = (intptr_t) GetSymbol( symname );
 442                         DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
 443                                 ptr, *ptr, val, (intptr_t)ptr );
 444                         *ptr = val + addend - (intptr_t)ptr;
 445                         //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 446                         break;
 447
 448                 // Absolute Value of a symbol (S)
 449                 case R_386_GLOB_DAT:
 450                 case R_386_JMP_SLOT:
 451                         DEBUGS(" elf_doRelocate: #%i: '%s'", sym, symname);
 452                         val = (intptr_t) GetSymbol( symname );
 453                         DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
 454                         *ptr = val;
 455                         break;
 456
 457                 // Base Address (B+A)
 458                 case R_386_RELATIVE:
 459                         DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 460                         *ptr = iBaseDiff + addend;
 461                         break;
 462
 463                 default:
 464                         DEBUGS(" elf_doRelocate: Rel 0x%x: 0x%x,%s", ptr, sym, csaR_NAMES[type]);
 465                         break;
 466                 }
 467         }
 468
 469         // Parse Relocation Entries
 470         if(rel && relSz)
 471         {
 472                 Uint32  *ptr;
 473                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 474                 j = relSz / relEntSz;
 475                 for( i = 0; i < j; i++ )
 476                 {
 477                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 478                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 479                         elf_doRelocate(rel[i].r_info, ptr, *ptr, dynsymtab);
 480                 }
 481         }
 482         // Parse Relocation Entries
 483         if(rela && relaSz)
 484         {
 485                 Uint32  *ptr;
 486                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 487                 j = relaSz / relaEntSz;
 488                 for( i = 0; i < j; i++ )
 489                 {
 490                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 491                         elf_doRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab);
 492                 }
 493         }
 494
 495         // === Process PLT (Procedure Linkage Table) ===
 496         if(plt && pltSz)
 497         {
 498                 Uint32  *ptr;
 499                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 500                 if(pltType == DT_REL)
 501                 {
 502                         Elf32_Rel       *pltRel = plt;
 503                         j = pltSz / sizeof(Elf32_Rel);
 504                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 505                         for(i=0;i<j;i++)
 506                         {
 507                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 508                                 elf_doRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab);
 509                         }
 510                 }
 511                 else
 512                 {
 513                         Elf32_Rela      *pltRela = plt;
 514                         j = pltSz / sizeof(Elf32_Rela);
 515                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 516                         for(i=0;i<j;i++)
 517                         {
 518                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 519                                 elf_doRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab);
 520                         }
 521                 }
 522         }
 523
 524         DEBUGS("ElfRelocate: RETURN 0x%x", hdr->entrypoint + iBaseDiff);
 525         return (void*)hdr->entrypoint + iBaseDiff;
 526 }
 527
 528
 529 /**
 530  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
 531  */
 532 int ElfGetSymbol(void *Base, const char *Name, void **ret)
 533 {
 534         Elf32_Ehdr      *hdr = Base;
 535         Elf32_Sym       *symtab;
 536          int    nbuckets = 0;
 537          int    iSymCount = 0;
 538          int    i;
 539         Uint32  *pBuckets;
 540         Uint32  *pChains;
 541         Uint    iNameHash;
 542         const char      *dynstrtab;
 543         uintptr_t       iBaseDiff = -1;
 544
 545         //DEBUGS("ElfGetSymbol: (Base=0x%x, Name='%s')", Base, Name);
 546         #if 0
 547         pBuckets = (void *) (intptr_t) hdr->misc.HashTable;
 548         symtab = (void *) (intptr_t) hdr->misc.SymTable;
 549         dynstrtab = (void *) (intptr_t) hdr->misc.StrTab;
 550         #else
 551         dynstrtab = NULL;
 552         pBuckets = NULL;
 553         symtab = NULL;
 554         #endif
 555
 556         // Catch the current executable
 557         if( !pBuckets )
 558         {
 559                 Elf32_Phdr      *phtab;
 560                 Elf32_Dyn       *dynTab = NULL;
 561                  int    j;
 562
 563                 // Locate the tables
 564                 phtab = (void*)( Base + hdr->phoff );
 565                 for( i = 0; i < hdr->phentcount; i ++ )
 566                 {
 567                         if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 568                                 iBaseDiff = phtab[i].VAddr;
 569                         if( phtab[i].Type == PT_DYNAMIC ) {
 570                                 dynTab = (void*)(intptr_t)phtab[i].VAddr;
 571                         }
 572                 }
 573                 if( !dynTab ) {
 574                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p");
 575                         return 0;
 576                 }
 577                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 578                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 579
 580                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 581                 {
 582                         switch(dynTab[j].d_tag)
 583                         {
 584                         // --- Symbol Table ---
 585                         case DT_SYMTAB:
 586                                 symtab = (void*)(intptr_t) dynTab[j].d_val;     // Rebased in Relocate
 587                                 break;
 588                         case DT_STRTAB:
 589                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_val;
 590                                 break;
 591                         // --- Hash Table --
 592                         case DT_HASH:
 593                                 pBuckets = (void*)(intptr_t) dynTab[j].d_val;
 594                                 break;
 595                         }
 596                 }
 597
 598                 #if 0
 599                 hdr->misc.HashTable = pBucktets;
 600                 hdr->misc.SymTable = symtab;
 601                 hdr->misc.StrTab = dynstrtab;
 602                 #endif
 603         }
 604
 605         nbuckets = pBuckets[0];
 606         iSymCount = pBuckets[1];
 607         pBuckets = &pBuckets[2];
 608         pChains = &pBuckets[ nbuckets ];
 609
 610         // Get hash
 611         iNameHash = ElfHashString(Name);
 612         iNameHash %= nbuckets;
 613         //DEBUGS(" ElfGetSymbol: iNameHash = 0x%x", iNameHash);
 614
 615         // Walk Chain
 616         i = pBuckets[ iNameHash ];
 617         //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")", symtab[i].name);
 618         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 619                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 620                 return 1;
 621         }
 622
 623         //DEBUGS(" ElfGetSymbol: Hash of first = 0x%x", ElfHashString( symtab[i].name ) % nbuckets);
 624         while(pChains[i] != STN_UNDEF)
 625         {
 626                 //DEBUGS(" pChains[%i] = %i", i, pChains[i]);
 627                 i = pChains[i];
 628                 //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")", symtab[ i ].name);
 629                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 630                         //DEBUGS("ElfGetSymbol: RETURN 1, '%s' = 0x%x", symtab[ i ].name, symtab[ i ].value);
 631                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 632                         return 1;
 633                 }
 634         }
 635
 636         //DEBUGS("ElfGetSymbol: RETURN 0, Symbol '%s' not found", Name);
 637         return 0;
 638 }
 639
 640 Uint32 ElfHashString(const char *name)
 641 {
 642         Uint32  h = 0, g;
 643         while(*name)
 644         {
 645                 h = (h << 4) + *(Uint8*)name++;
 646                 if( (g = h & 0xf0000000) )
 647                         h ^= g >> 24;
 648                 h &= ~g;
 649         }
 650         return h;
 651 }
 652
 653 #if 0
 654 unsigned long elf_hash(const unsigned char *name)
 655 {
 656         unsigned long   h = 0, g;
 657         while (*name)
 658         {
 659                 h = (h << 4) + *name++;
 660                 if (g = h & 0xf0000000)
 661                         h ^= g >> 24;
 662                 h &= ~g;
 663         }
 664         return h;
 665 }
 666 #endif