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

   1 /*
   2  * Acess2 Dynamic Linker
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * elf.c
   6  * - ELF32/ELF64 relocation
   7  */
   8 #define DEBUG   0
   9
  10 #include "common.h"
  11 #include <stdint.h>
  12 #include "elf32.h"
  13 #include "elf64.h"
  14
  15 #if DEBUG
  16 # define        DEBUGS(v...)    SysDebug("ld-acess - " v)
  17 #else
  18 # define        DEBUGS(...)
  19 #endif
  20
  21 //#if BITS > 32
  22 # define SUPPORT_ELF64
  23 //#endif
  24
  25 // === CONSTANTS ===
  26 #if DEBUG
  27 //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"};
  28 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"};
  29 #endif
  30
  31 // === PROTOTYPES ===
  32 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  33  int    ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  34 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  35  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  36 #ifdef SUPPORT_ELF64
  37 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  38  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  39 #endif
  40 uint32_t        ElfHashString(const char *name);
  41
  42 // === CODE ===
  43 /**
  44  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  45  * \brief Relocates a loaded ELF Executable
  46  */
  47 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  48 {
  49         Elf32_Ehdr      *hdr = Base;
  50
  51         switch(hdr->e_ident[4])
  52         {
  53         case ELFCLASS32:
  54                 return Elf32Relocate(Base, envp, Filename);
  55 #ifdef SUPPORT_ELF64
  56         case ELFCLASS64:
  57                 return Elf64Relocate(Base, envp, Filename);
  58 #endif
  59         default:
  60                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  61                 return NULL;
  62         }
  63 }
  64
  65 /**
  66  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  67  */
  68 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  69 {
  70         Elf32_Ehdr      *hdr = Base;
  71
  72         switch(hdr->e_ident[4])
  73         {
  74         case ELFCLASS32:
  75                 return Elf32GetSymbol(Base, Name, ret, Size);
  76 #ifdef SUPPORT_ELF64
  77         case ELFCLASS64:
  78                 return Elf64GetSymbol(Base, Name, ret, Size);
  79 #endif
  80         default:
  81                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  82                 return 0;
  83         }
  84 }
  85
  86 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
  87 {
  88         Elf32_Ehdr      *hdr = Base;
  89         Elf32_Phdr      *phtab;
  90          int    i, j;   // Counters
  91         char    *libPath;
  92         intptr_t        iRealBase = -1;
  93         intptr_t        iBaseDiff;
  94          int    iSegmentCount;
  95 //       int    iSymCount;
  96         Elf32_Rel       *rel = NULL;
  97         Elf32_Rela      *rela = NULL;
  98         void    *plt = NULL;
  99          int    relSz=0, relEntSz=8;
 100          int    relaSz=0, relaEntSz=8;
 101          int    pltSz=0, pltType=0;
 102         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 103         char    *dynstrtab = NULL;      // .dynamic String Table
 104         Elf32_Sym       *dynsymtab;
 105         void    (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym);
 106
 107         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 108
 109         // Check magic header
 110
 111
 112         // Parse Program Header to get Dynamic Table
 113         phtab = Base + hdr->phoff;
 114         iSegmentCount = hdr->phentcount;
 115         for(i=0;i<iSegmentCount;i++)
 116         {
 117                 // Determine linked base address
 118                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 119                         iRealBase = phtab[i].VAddr;
 120
 121                 // Find Dynamic Section
 122                 if(phtab[i].Type == PT_DYNAMIC) {
 123                         if(dynamicTab) {
 124                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 125                                 continue;
 126                         }
 127                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 128                         j = i;  // Save Dynamic Table ID
 129                 }
 130         }
 131
 132         // Page Align real base
 133         iRealBase &= ~0xFFF;
 134         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 135
 136         // Adjust "Real" Base
 137         iBaseDiff = (intptr_t)Base - iRealBase;
 138
 139 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 140
 141         // Check if a PT_DYNAMIC segement was found
 142         if(!dynamicTab) {
 143                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 144                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 145         }
 146
 147         // Adjust Dynamic Table
 148         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 149
 150         // === Get Symbol table and String Table ===
 151         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 152         {
 153                 switch(dynamicTab[j].d_tag)
 154                 {
 155                 // --- Symbol Table ---
 156                 case DT_SYMTAB:
 157                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 158                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 159                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 160                         dynsymtab = (void*)(intptr_t)dynamicTab[j].d_val;
 161                         break;
 162                 // --- String Table ---
 163                 case DT_STRTAB:
 164                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 165                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 166                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 167                         dynstrtab = (void*)(intptr_t)dynamicTab[j].d_val;
 168                         break;
 169                 // --- Hash Table --
 170                 case DT_HASH:
 171                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 172 //                      iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
 173                         break;
 174                 }
 175         }
 176
 177         if(dynsymtab == NULL) {
 178                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 179                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 180         }
 181
 182         // === Add to loaded list (can be imported now) ===
 183         AddLoaded( Filename, Base );
 184
 185         // === Parse Relocation Data ===
 186         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 187         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 188         {
 189                 switch(dynamicTab[j].d_tag)
 190                 {
 191                 // --- Shared Library Name ---
 192                 case DT_SONAME:
 193                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 194                         break;
 195                 // --- Needed Library ---
 196                 case DT_NEEDED:
 197                         libPath = dynstrtab + dynamicTab[j].d_val;
 198                         DEBUGS(" Required Library '%s'", libPath);
 199                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 200                                 #if DEBUG
 201                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 202                                 #else
 203                                 SysDebug("Unable to load required library '%s'", libPath);
 204                                 #endif
 205                                 return 0;
 206                         }
 207                         DEBUGS(" Lib loaded");
 208                         break;
 209                 // --- PLT/GOT ---
 210 //              case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 211                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 212                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 213                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 214
 215                 // --- Relocation ---
 216                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 217                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 218                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 219                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 220                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 221                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 222
 223                 // --- Symbol Table ---
 224                 case DT_SYMTAB:
 225                 // --- Hash Table ---
 226                 case DT_HASH:
 227                 // --- String Table ---
 228                 case DT_STRTAB:
 229                         break;
 230
 231                 // --- Unknown ---
 232                 default:
 233                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 234                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 235                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 236                         break;
 237                 }
 238         }
 239
 240         DEBUGS(" elf_relocate: Beginning Relocation");
 241
 242         void elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
 243         {
 244                 intptr_t        val;
 245                 switch( type )
 246                 {
 247                 // Standard 32 Bit Relocation (S+A)
 248                 case R_386_32:
 249                         val = (intptr_t) GetSymbol(Sym, NULL);
 250                         DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
 251                                         ptr, val, Sym);
 252                         *ptr = val + addend;
 253                         break;
 254
 255                 // 32 Bit Relocation wrt. Offset (S+A-P)
 256                 case R_386_PC32:
 257                         DEBUGS(" elf_doRelocate: '%s'", Sym);
 258                         val = (intptr_t) GetSymbol(Sym, NULL);
 259                         DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
 260                                 ptr, *ptr, val, (intptr_t)ptr );
 261                         *ptr = val + addend - (intptr_t)ptr;
 262                         //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 263                         break;
 264
 265                 // Absolute Value of a symbol (S)
 266                 case R_386_GLOB_DAT:
 267                 case R_386_JMP_SLOT:
 268                         DEBUGS(" elf_doRelocate: '%s'", Sym);
 269                         val = (intptr_t) GetSymbol( Sym, NULL );
 270                         DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
 271                         *ptr = val;
 272                         break;
 273
 274                 // Base Address (B+A)
 275                 case R_386_RELATIVE:
 276                         DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 277                         *ptr = iBaseDiff + addend;
 278                         break;
 279
 280                 case R_386_COPY: {
 281                         size_t  size;
 282                         void    *src = GetSymbol(Sym, &size);
 283                         DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, src, size);
 284                         memcpy(ptr, src, size);
 285                         break; }
 286
 287                 default:
 288                         SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 289                         break;
 290                 }
 291         }
 292
 293         void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
 294         {
 295                 uint32_t        val;
 296                 switch(type)
 297                 {
 298                 // (S + A) | T
 299                 case R_ARM_GLOB_DAT:
 300                         DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
 301                         val = (intptr_t)GetSymbol(Sym, NULL);
 302                         *ptr = val + addend;
 303                         break;
 304                 case R_ARM_JUMP_SLOT:
 305                         if(!bRela)      addend = 0;
 306                         DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
 307                         val = (intptr_t)GetSymbol(Sym, NULL);
 308                         *ptr = val + addend;
 309                         break;
 310                 default:
 311                         SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 312                         break;
 313                 }
 314         }
 315
 316         void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend)
 317         {
 318                  int    type = ELF32_R_TYPE(r_info);
 319                  int    sym = ELF32_R_SYM(r_info);
 320                 const char      *symname = dynstrtab + dynsymtab[sym].nameOfs;
 321                 do_relocate(r_info, ptr, addend, type, bRela, symname);
 322         }
 323
 324         switch(hdr->machine)
 325         {
 326         case EM_386:
 327                 do_relocate = elf_doRelocate_386;
 328                 break;
 329         case EM_ARM:
 330                 do_relocate = elf_doRelocate_arm;
 331                 break;
 332         default:
 333                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 334                 break;
 335         }
 336
 337         // Parse Relocation Entries
 338         if(rel && relSz)
 339         {
 340                 Elf32_Word      *ptr;
 341                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 342                 j = relSz / relEntSz;
 343                 for( i = 0; i < j; i++ )
 344                 {
 345                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 346                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 347                         _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 348                 }
 349         }
 350         // Parse Relocation Entries
 351         if(rela && relaSz)
 352         {
 353                 Elf32_Word      *ptr;
 354                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 355                 j = relaSz / relaEntSz;
 356                 for( i = 0; i < j; i++ )
 357                 {
 358                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 359                         _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 360                 }
 361         }
 362
 363         // === Process PLT (Procedure Linkage Table) ===
 364         if(plt && pltSz)
 365         {
 366                 Elf32_Word      *ptr;
 367                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 368                 if(pltType == DT_REL)
 369                 {
 370                         Elf32_Rel       *pltRel = plt;
 371                         j = pltSz / sizeof(Elf32_Rel);
 372                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 373                         for(i=0;i<j;i++)
 374                         {
 375                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 376                                 _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 377                         }
 378                 }
 379                 else
 380                 {
 381                         Elf32_Rela      *pltRela = plt;
 382                         j = pltSz / sizeof(Elf32_Rela);
 383                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 384                         for(i=0;i<j;i++)
 385                         {
 386                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 387                                 _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 388                         }
 389                 }
 390         }
 391
 392         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 393         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 394 }
 395
 396 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 397 {
 398         Elf32_Ehdr      *hdr = Base;
 399         Elf32_Sym       *symtab;
 400          int    nbuckets = 0;
 401 //       int    iSymCount = 0;
 402          int    i;
 403         Elf32_Word      *pBuckets;
 404         Elf32_Word      *pChains;
 405         uint32_t        iNameHash;
 406         const char      *dynstrtab;
 407         uintptr_t       iBaseDiff = -1;
 408         Elf32_Phdr      *phtab;
 409         Elf32_Dyn       *dynTab = NULL;
 410
 411         // Locate the tables
 412         phtab = (void*)( Base + hdr->phoff );
 413         for( i = 0; i < hdr->phentcount; i ++ )
 414         {
 415                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 416                         iBaseDiff = phtab[i].VAddr;
 417                 if( phtab[i].Type == PT_DYNAMIC ) {
 418                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 419                 }
 420         }
 421         if( !dynTab ) {
 422                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 423                 return 0;
 424         }
 425         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 426         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 427         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 428         {
 429                 switch(dynTab[i].d_tag)
 430                 {
 431                 // --- Symbol Table ---
 432                 case DT_SYMTAB:
 433                         symtab = (void*)(intptr_t) dynTab[i].d_val;     // Rebased in Relocate
 434                         break;
 435                 case DT_STRTAB:
 436                         dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
 437                         break;
 438                 // --- Hash Table --
 439                 case DT_HASH:
 440                         pBuckets = (void*)(intptr_t) dynTab[i].d_val;
 441                         break;
 442                 }
 443         }
 444
 445         nbuckets = pBuckets[0];
 446 //      iSymCount = pBuckets[1];
 447         pBuckets = &pBuckets[2];
 448         pChains = &pBuckets[ nbuckets ];
 449
 450         // Get hash
 451         iNameHash = ElfHashString(Name);
 452         iNameHash %= nbuckets;
 453
 454         // Walk Chain
 455         i = pBuckets[ iNameHash ];
 456         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 457                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 458                 if(Size)        *Size = symtab[i].size;
 459                 return 1;
 460         }
 461
 462         while(pChains[i] != STN_UNDEF)
 463         {
 464                 i = pChains[i];
 465                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 466                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 467                         if(Size)        *Size = symtab[i].size;
 468                         return 1;
 469                 }
 470         }
 471
 472         return 0;
 473 }
 474
 475 #ifdef SUPPORT_ELF64
 476 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 477 {
 478          int    i;
 479         Elf64_Ehdr      *hdr = Base;
 480         Elf64_Phdr      *phtab;
 481         Elf64_Dyn       *dyntab;
 482         Elf64_Addr      compiledBase = -1, baseDiff;
 483         Elf64_Sym       *symtab = NULL;
 484         char    *strtab = NULL;
 485         Elf64_Word      *hashtab = NULL;
 486         Elf64_Rel       *rel = NULL;
 487          int    rel_count = 0;
 488         Elf64_Rela      *rela = NULL;
 489          int    rela_count = 0;
 490         void    *pltrel = NULL;
 491          int    plt_size = 0, plt_type = 0;
 492
 493         DEBUGS("Elf64Relocate: hdr = {");
 494         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 495         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 496         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 497         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 498         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 499         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 500         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 501         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 502         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 503         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 504         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 505
 506         // Scan for the dynamic table (and find the compiled base)
 507         phtab = Base + hdr->e_phoff;
 508         for( i = 0; i < hdr->e_phnum; i ++ )
 509         {
 510                 if(phtab[i].p_type == PT_DYNAMIC)
 511                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 512                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 513                         compiledBase = phtab[i].p_vaddr;
 514         }
 515
 516         baseDiff = (uintptr_t)Base - compiledBase;
 517
 518         DEBUGS("baseDiff = %p", baseDiff);
 519
 520         if(dyntab == NULL) {
 521                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 522                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 523         }
 524
 525         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 526
 527         // Parse the dynamic table (first pass)
 528         // - Search for String, Symbol and Hash tables
 529         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 530         {
 531                 switch(dyntab[i].d_tag)
 532                 {
 533                 case DT_SYMTAB:
 534                         dyntab[i].d_un.d_ptr += baseDiff;
 535                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 536                         break;
 537                 case DT_STRTAB:
 538                         dyntab[i].d_un.d_ptr += baseDiff;
 539                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 540                         break;
 541                 case DT_HASH:
 542                         dyntab[i].d_un.d_ptr += baseDiff;
 543                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 544                         break;
 545                 }
 546         }
 547
 548         if( !symtab || !strtab || !hashtab ) {
 549                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 550                 return NULL;
 551         }
 552
 553         // Ready for symbol use
 554         AddLoaded( Filename, Base );
 555
 556         // Second pass on dynamic table
 557         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 558         {
 559                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 560                 switch(dyntab[i].d_tag)
 561                 {
 562                 case DT_SONAME: break;
 563
 564                 case DT_NEEDED: {
 565                         char *libPath = strtab + dyntab[i].d_un.d_val;
 566                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 567                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 568                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 569                                 return NULL;
 570                         }
 571                         } break;
 572
 573                 // Relocation entries
 574                 case DT_REL:
 575                         dyntab[i].d_un.d_ptr += baseDiff;
 576                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 577                         break;
 578                 case DT_RELSZ:
 579                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 580                         break;
 581                 case DT_RELENT:
 582                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 583                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 584                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 585                                 return NULL;
 586                         }
 587                         break;
 588                 case DT_RELA:
 589                         dyntab[i].d_un.d_ptr += baseDiff;
 590                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 591                         break;
 592                 case DT_RELASZ:
 593                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 594                         break;
 595                 case DT_RELAENT:
 596                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 597                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 598                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 599                                 return NULL;
 600                         }
 601                         break;
 602                 case DT_JMPREL:
 603                         dyntab[i].d_un.d_ptr += baseDiff;
 604                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 605                         break;
 606                 case DT_PLTREL:
 607                         plt_type = dyntab[i].d_un.d_val;
 608                         break;
 609                 case DT_PLTRELSZ:
 610                         plt_size = dyntab[i].d_un.d_val;
 611                         break;
 612                 }
 613         }
 614
 615         // Relocation function
 616         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 617         {
 618                  int    sym = ELF64_R_SYM(r_info);
 619                  int    type = ELF64_R_TYPE(r_info);
 620                 const char      *symname = strtab + symtab[sym].st_name;
 621                 switch( type )
 622                 {
 623                 case R_X86_64_NONE:
 624                         break;
 625                 case R_X86_64_64:
 626                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL) + addend;
 627                         break;
 628                 case R_X86_64_COPY: {
 629                         size_t  size;
 630                         void    *sym = GetSymbol(symname, &size);
 631                         memcpy(ptr, sym, size);
 632                         } break;
 633                 case R_X86_64_GLOB_DAT:
 634                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 635                         break;
 636                 case R_X86_64_JUMP_SLOT:
 637                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 638                         break;
 639                 case R_X86_64_RELATIVE:
 640                         *(uint64_t*)ptr = (uintptr_t)Base + addend;
 641                         break;
 642                 default:
 643                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 644                         break;
 645                 }
 646         }
 647
 648         if( rel )
 649         {
 650                 DEBUGS("rel_count = %i", rel_count);
 651                 for( i = 0; i < rel_count; i ++ )
 652                 {
 653                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 654                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 655                 }
 656         }
 657
 658         if( rela )
 659         {
 660                 DEBUGS("rela_count = %i", rela_count);
 661                 for( i = 0; i < rela_count; i ++ )
 662                 {
 663                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 664                         _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 665                 }
 666         }
 667
 668         if( pltrel && plt_type )
 669         {
 670                 if( plt_type == DT_REL ) {
 671                         Elf64_Rel       *plt = pltrel;
 672                          int    count = plt_size / sizeof(Elf64_Rel);
 673                         DEBUGS("plt rel count = %i", count);
 674                         for( i = 0; i < count; i ++ )
 675                         {
 676                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 677                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 678                         }
 679                 }
 680                 else {
 681                         Elf64_Rela      *plt = pltrel;
 682                          int    count = plt_size / sizeof(Elf64_Rela);
 683                         DEBUGS("plt rela count = %i", count);
 684                         for( i = 0; i < count; i ++ )
 685                         {
 686                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 687                                 _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 688                         }
 689                 }
 690         }
 691
 692         DEBUGS("Elf64Relocate: Relocations done, return %p", (void *)(hdr->e_entry + baseDiff));
 693         return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 694 }
 695
 696 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 697 {
 698         Elf64_Ehdr      *hdr = Base;
 699         Elf64_Sym       *symtab;
 700          int    nbuckets = 0;
 701 //       int    iSymCount = 0;
 702          int    i;
 703         Elf64_Word      *pBuckets;
 704         Elf64_Word      *pChains;
 705         uint32_t        iNameHash;
 706         const char      *dynstrtab;
 707         uintptr_t       iBaseDiff = -1;
 708
 709         dynstrtab = NULL;
 710         pBuckets = NULL;
 711         symtab = NULL;
 712
 713         // Catch the current executable
 714         if( !pBuckets )
 715         {
 716                 Elf64_Phdr      *phtab;
 717                 Elf64_Dyn       *dynTab = NULL;
 718                  int    j;
 719
 720                 // Locate the tables
 721                 phtab = (void*)( Base + hdr->e_phoff );
 722                 for( i = 0; i < hdr->e_phnum; i ++ )
 723                 {
 724                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 725                                 iBaseDiff = phtab[i].p_vaddr;
 726                         if( phtab[i].p_type == PT_DYNAMIC ) {
 727                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 728                         }
 729                 }
 730                 if( !dynTab ) {
 731                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 732                         return 0;
 733                 }
 734                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 735                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 736
 737                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 738                 {
 739                         switch(dynTab[j].d_tag)
 740                         {
 741                         // --- Symbol Table ---
 742                         case DT_SYMTAB:
 743                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 744                                 break;
 745                         case DT_STRTAB:
 746                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 747                                 break;
 748                         // --- Hash Table --
 749                         case DT_HASH:
 750                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 751                                 break;
 752                         }
 753                 }
 754         }
 755
 756         nbuckets = pBuckets[0];
 757 //      iSymCount = pBuckets[1];
 758         pBuckets = &pBuckets[2];
 759         pChains = &pBuckets[ nbuckets ];
 760
 761         // Get hash
 762         iNameHash = ElfHashString(Name);
 763         iNameHash %= nbuckets;
 764
 765         // Walk Chain
 766         i = pBuckets[ iNameHash ];
 767         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 768                 *Ret = (void*) (intptr_t) symtab[i].st_value + iBaseDiff;
 769                 if(Size)        *Size = symtab[i].st_size;
 770                 DEBUGS("%s = %p", Name, *Ret);
 771                 return 1;
 772         }
 773
 774         while(pChains[i] != STN_UNDEF)
 775         {
 776                 i = pChains[i];
 777                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 778                         *Ret = (void*)(intptr_t)symtab[i].st_value + iBaseDiff;
 779                         if(Size)        *Size = symtab[i].st_size;
 780                         DEBUGS("%s = %p", Name, *Ret);
 781                         return 1;
 782                 }
 783         }
 784
 785         return 0;
 786 }
 787 #endif
 788
 789
 790 uint32_t ElfHashString(const char *name)
 791 {
 792         uint32_t        h = 0, g;
 793         while(*name)
 794         {
 795                 h = (h << 4) + *(uint8_t*)name++;
 796                 if( (g = h & 0xf0000000) )
 797                         h ^= g >> 24;
 798                 h &= ~g;
 799         }
 800         return h;
 801 }
 802