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 #ifndef DISABLE_ELF64
  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 void    elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  37 void    elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  38 #ifdef SUPPORT_ELF64
  39 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  40  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  41 #endif
  42 uint32_t        ElfHashString(const char *name);
  43
  44 // === CODE ===
  45 /**
  46  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  47  * \brief Relocates a loaded ELF Executable
  48  */
  49 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  50 {
  51         Elf32_Ehdr      *hdr = Base;
  52
  53         switch(hdr->e_ident[4])
  54         {
  55         case ELFCLASS32:
  56                 return Elf32Relocate(Base, envp, Filename);
  57 #ifdef SUPPORT_ELF64
  58         case ELFCLASS64:
  59                 return Elf64Relocate(Base, envp, Filename);
  60 #endif
  61         default:
  62                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  63                 return NULL;
  64         }
  65 }
  66
  67 /**
  68  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  69  */
  70 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  71 {
  72         Elf32_Ehdr      *hdr = Base;
  73
  74         switch(hdr->e_ident[4])
  75         {
  76         case ELFCLASS32:
  77                 return Elf32GetSymbol(Base, Name, ret, Size);
  78 #ifdef SUPPORT_ELF64
  79         case ELFCLASS64:
  80                 return Elf64GetSymbol(Base, Name, ret, Size);
  81 #endif
  82         default:
  83                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  84                 return 0;
  85         }
  86 }
  87
  88 void elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
  89 {
  90         intptr_t        val;
  91         switch( type )
  92         {
  93         // Standard 32 Bit Relocation (S+A)
  94         case R_386_32:
  95                 val = (intptr_t) GetSymbol(Sym, NULL);
  96                 DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
  97                                 ptr, val, Sym);
  98                 *ptr = val + addend;
  99                 break;
 100
 101         // 32 Bit Relocation wrt. Offset (S+A-P)
 102         case R_386_PC32:
 103                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 104                 val = (intptr_t) GetSymbol(Sym, NULL);
 105                 DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
 106                         ptr, *ptr, val, (intptr_t)ptr );
 107                 *ptr = val + addend - (intptr_t)ptr;
 108                 //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 109                 break;
 110
 111         // Absolute Value of a symbol (S)
 112         case R_386_GLOB_DAT:
 113         case R_386_JMP_SLOT:
 114                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 115                 val = (intptr_t) GetSymbol( Sym, NULL );
 116                 DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
 117                 *ptr = val;
 118                 break;
 119
 120         // Base Address (B+A)
 121         case R_386_RELATIVE:
 122                 DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 123                 *ptr = iBaseDiff + addend;
 124                 break;
 125
 126         case R_386_COPY: {
 127                 size_t  size;
 128                 void    *src = GetSymbol(Sym, &size);
 129                 DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, src, size);
 130                 memcpy(ptr, src, size);
 131                 break; }
 132
 133         default:
 134                 SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 135                 break;
 136         }
 137 }
 138
 139 void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
 140 {
 141         uint32_t        val;
 142         switch(type)
 143         {
 144         // (S + A) | T
 145         case R_ARM_ABS32:
 146                 DEBUGS(" elf_doRelocate_arm: R_ARM_ABS32 %p (%s + %x)", ptr, Sym, addend);
 147                 val = (intptr_t)GetSymbol(Sym, NULL);
 148                 *ptr = val + addend;
 149                 break;
 150         case R_ARM_GLOB_DAT:
 151                 DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
 152                 val = (intptr_t)GetSymbol(Sym, NULL);
 153                 *ptr = val + addend;
 154                 break;
 155         case R_ARM_JUMP_SLOT:
 156                 if(!bRela)      addend = 0;
 157                 DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
 158                 val = (intptr_t)GetSymbol(Sym, NULL);
 159                 *ptr = val + addend;
 160                 break;
 161         // Copy
 162         case R_ARM_COPY: {
 163                 size_t  size;
 164                 void    *src = GetSymbol(Sym, &size);
 165                 DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size);
 166                 memcpy(ptr, src, size);
 167                 break; }
 168         // Delta between link and runtime locations + A
 169         case R_ARM_RELATIVE:
 170                 if(Sym[0] != '\0') {
 171                         // TODO: Get delta for a symbol
 172                         SysDebug("elf_doRelocate_arm: TODO - Implment R_ARM_RELATIVE for symbols");
 173                 }
 174                 else {
 175                         *ptr = iBaseDiff + addend;
 176                 }
 177                 break;
 178         default:
 179                 SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 180                 break;
 181         }
 182 }
 183
 184 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 185 {
 186         Elf32_Ehdr      *hdr = Base;
 187         Elf32_Phdr      *phtab;
 188          int    i, j;   // Counters
 189         char    *libPath;
 190         intptr_t        iRealBase = -1;
 191         intptr_t        iBaseDiff;
 192          int    iSegmentCount;
 193 //       int    iSymCount;
 194         Elf32_Rel       *rel = NULL;
 195         Elf32_Rela      *rela = NULL;
 196         void    *plt = NULL;
 197          int    relSz=0, relEntSz=8;
 198          int    relaSz=0, relaEntSz=8;
 199          int    pltSz=0, pltType=0;
 200         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 201         char    *dynstrtab = NULL;      // .dynamic String Table
 202         Elf32_Sym       *dynsymtab;
 203         void    (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym, intptr_t iBaseDiff);
 204         auto void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend);
 205
 206         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 207
 208         // Check magic header
 209
 210
 211         // Parse Program Header to get Dynamic Table
 212         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 213         iSegmentCount = hdr->phentcount;
 214         for(i=0;i<iSegmentCount;i++)
 215         {
 216                 // Determine linked base address
 217                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 218                         iRealBase = phtab[i].VAddr;
 219
 220                 // Find Dynamic Section
 221                 if(phtab[i].Type == PT_DYNAMIC) {
 222                         if(dynamicTab) {
 223                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 224                                 continue;
 225                         }
 226                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 227                         j = i;  // Save Dynamic Table ID
 228                 }
 229         }
 230
 231         // Page Align real base
 232         iRealBase &= ~0xFFF;
 233         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 234
 235         // Adjust "Real" Base
 236         iBaseDiff = (intptr_t)Base - iRealBase;
 237
 238 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 239
 240         // Check if a PT_DYNAMIC segement was found
 241         if(!dynamicTab) {
 242                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 243                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 244         }
 245
 246         // Adjust Dynamic Table
 247         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 248
 249         // === Get Symbol table and String Table ===
 250         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 251         {
 252                 switch(dynamicTab[j].d_tag)
 253                 {
 254                 // --- Symbol Table ---
 255                 case DT_SYMTAB:
 256                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 257                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 258                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 259                         dynsymtab = (void*)(intptr_t)dynamicTab[j].d_val;
 260                         break;
 261                 // --- String Table ---
 262                 case DT_STRTAB:
 263                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 264                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 265                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 266                         dynstrtab = (void*)(intptr_t)dynamicTab[j].d_val;
 267                         break;
 268                 // --- Hash Table --
 269                 case DT_HASH:
 270                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 271 //                      iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
 272                         break;
 273                 }
 274         }
 275
 276         if(dynsymtab == NULL) {
 277                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 278                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 279         }
 280
 281         // === Add to loaded list (can be imported now) ===
 282         AddLoaded( Filename, Base );
 283
 284         // === Parse Relocation Data ===
 285         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 286         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 287         {
 288                 switch(dynamicTab[j].d_tag)
 289                 {
 290                 // --- Shared Library Name ---
 291                 case DT_SONAME:
 292                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 293                         break;
 294                 // --- Needed Library ---
 295                 case DT_NEEDED:
 296                         libPath = dynstrtab + dynamicTab[j].d_val;
 297                         DEBUGS(" Required Library '%s'", libPath);
 298                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 299                                 #if DEBUG
 300                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 301                                 #else
 302                                 SysDebug("Unable to load required library '%s'", libPath);
 303                                 #endif
 304                                 return 0;
 305                         }
 306                         DEBUGS(" Lib loaded");
 307                         break;
 308                 // --- PLT/GOT ---
 309 //              case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 310                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 311                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 312                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 313
 314                 // --- Relocation ---
 315                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 316                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 317                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 318                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 319                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 320                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 321
 322                 // --- Symbol Table ---
 323                 case DT_SYMTAB:
 324                 // --- Hash Table ---
 325                 case DT_HASH:
 326                 // --- String Table ---
 327                 case DT_STRTAB:
 328                         break;
 329
 330                 // --- Unknown ---
 331                 default:
 332                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 333                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 334                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 335                         break;
 336                 }
 337         }
 338
 339         DEBUGS(" elf_relocate: Beginning Relocation");
 340
 341         void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend)
 342         {
 343                  int    type = ELF32_R_TYPE(r_info);
 344                  int    sym = ELF32_R_SYM(r_info);
 345                 const char      *symname = dynstrtab + dynsymtab[sym].nameOfs;
 346                 do_relocate(r_info, ptr, addend, type, bRela, symname, iBaseDiff);
 347         }
 348
 349         switch(hdr->machine)
 350         {
 351         case EM_386:
 352                 do_relocate = elf_doRelocate_386;
 353                 break;
 354         case EM_ARM:
 355                 do_relocate = elf_doRelocate_arm;
 356                 break;
 357         default:
 358                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 359                 break;
 360         }
 361
 362         DEBUGS("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
 363
 364         // Parse Relocation Entries
 365         if(rel && relSz)
 366         {
 367                 Elf32_Word      *ptr;
 368                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 369                 j = relSz / relEntSz;
 370                 for( i = 0; i < j; i++ )
 371                 {
 372                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 373                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 374                         _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 375                 }
 376         }
 377         // Parse Relocation Entries
 378         if(rela && relaSz)
 379         {
 380                 Elf32_Word      *ptr;
 381                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 382                 j = relaSz / relaEntSz;
 383                 for( i = 0; i < j; i++ )
 384                 {
 385                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 386                         _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 387                 }
 388         }
 389
 390         // === Process PLT (Procedure Linkage Table) ===
 391         if(plt && pltSz)
 392         {
 393                 Elf32_Word      *ptr;
 394                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 395                 if(pltType == DT_REL)
 396                 {
 397                         Elf32_Rel       *pltRel = plt;
 398                         j = pltSz / sizeof(Elf32_Rel);
 399                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 400                         for(i=0;i<j;i++)
 401                         {
 402                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 403                                 _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 404                         }
 405                 }
 406                 else
 407                 {
 408                         Elf32_Rela      *pltRela = plt;
 409                         j = pltSz / sizeof(Elf32_Rela);
 410                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 411                         for(i=0;i<j;i++)
 412                         {
 413                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 414                                 _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 415                         }
 416                 }
 417         }
 418
 419         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 420         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 421 }
 422
 423 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 424 {
 425         Elf32_Ehdr      *hdr = Base;
 426         Elf32_Sym       *symtab = NULL;
 427          int    nbuckets = 0;
 428         Elf32_Word      *pBuckets = NULL;
 429         Elf32_Word      *pChains;
 430         uint32_t        iNameHash;
 431         const char      *dynstrtab = NULL;
 432         uintptr_t       iBaseDiff = -1;
 433         Elf32_Phdr      *phtab;
 434         Elf32_Dyn       *dynTab = NULL;
 435          int    i;
 436
 437         // Locate the tables
 438         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 439         for( i = 0; i < hdr->phentcount; i ++ )
 440         {
 441                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 442                         iBaseDiff = phtab[i].VAddr;
 443                 if( phtab[i].Type == PT_DYNAMIC ) {
 444                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 445                 }
 446         }
 447         if( !dynTab ) {
 448                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 449                 return 0;
 450         }
 451         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 452         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 453         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 454         {
 455                 switch(dynTab[i].d_tag)
 456                 {
 457                 // --- Symbol Table ---
 458                 case DT_SYMTAB:
 459                         symtab = (void*)(intptr_t) dynTab[i].d_val;     // Rebased in Relocate
 460                         break;
 461                 case DT_STRTAB:
 462                         dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
 463                         break;
 464                 // --- Hash Table --
 465                 case DT_HASH:
 466                         pBuckets = (void*)(intptr_t) dynTab[i].d_val;
 467                         break;
 468                 }
 469         }
 470
 471         if( !symtab ) {
 472                 SysDebug("ERRO - No DT_SYMTAB in %p", Base);
 473                 return 0;
 474         }
 475         if( !pBuckets ) {
 476                 SysDebug("ERRO - No DT_HASH in %p", Base);
 477                 return 0;
 478         }
 479         if( !dynstrtab ) {
 480                 SysDebug("ERRO - No DT_STRTAB in %p", Base);
 481                 return 0;
 482         }
 483
 484         nbuckets = pBuckets[0];
 485 //      iSymCount = pBuckets[1];
 486         pBuckets = &pBuckets[2];
 487         pChains = &pBuckets[ nbuckets ];
 488
 489         // Get hash
 490         iNameHash = ElfHashString(Name);
 491         iNameHash %= nbuckets;
 492
 493         // Walk Chain
 494         i = pBuckets[ iNameHash ];
 495         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 496                 *ret = (void*)( (uintptr_t) symtab[ i ].value + iBaseDiff );
 497                 if(Size)        *Size = symtab[i].size;
 498                 return 1;
 499         }
 500
 501         while(pChains[i] != STN_UNDEF)
 502         {
 503                 i = pChains[i];
 504                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 505                         *ret = (void*)( (uintptr_t)symtab[ i ].value + iBaseDiff );
 506                         if(Size)        *Size = symtab[i].size;
 507                         return 1;
 508                 }
 509         }
 510
 511         return 0;
 512 }
 513
 514 #ifdef SUPPORT_ELF64
 515 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 516 {
 517          int    i;
 518         Elf64_Ehdr      *hdr = Base;
 519         Elf64_Phdr      *phtab;
 520         Elf64_Dyn       *dyntab;
 521         Elf64_Addr      compiledBase = -1, baseDiff;
 522         Elf64_Sym       *symtab = NULL;
 523         char    *strtab = NULL;
 524         Elf64_Word      *hashtab = NULL;
 525         Elf64_Rel       *rel = NULL;
 526          int    rel_count = 0;
 527         Elf64_Rela      *rela = NULL;
 528          int    rela_count = 0;
 529         void    *pltrel = NULL;
 530          int    plt_size = 0, plt_type = 0;
 531
 532         DEBUGS("Elf64Relocate: hdr = {");
 533         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 534         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 535         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 536         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 537         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 538         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 539         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 540         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 541         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 542         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 543         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 544
 545         // Scan for the dynamic table (and find the compiled base)
 546         phtab = Base + hdr->e_phoff;
 547         for( i = 0; i < hdr->e_phnum; i ++ )
 548         {
 549                 if(phtab[i].p_type == PT_DYNAMIC)
 550                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 551                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 552                         compiledBase = phtab[i].p_vaddr;
 553         }
 554
 555         baseDiff = (uintptr_t)Base - compiledBase;
 556
 557         DEBUGS("baseDiff = %p", baseDiff);
 558
 559         if(dyntab == NULL) {
 560                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 561                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 562         }
 563
 564         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 565
 566         // Parse the dynamic table (first pass)
 567         // - Search for String, Symbol and Hash tables
 568         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 569         {
 570                 switch(dyntab[i].d_tag)
 571                 {
 572                 case DT_SYMTAB:
 573                         dyntab[i].d_un.d_ptr += baseDiff;
 574                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 575                         break;
 576                 case DT_STRTAB:
 577                         dyntab[i].d_un.d_ptr += baseDiff;
 578                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 579                         break;
 580                 case DT_HASH:
 581                         dyntab[i].d_un.d_ptr += baseDiff;
 582                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 583                         break;
 584                 }
 585         }
 586
 587         if( !symtab || !strtab || !hashtab ) {
 588                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 589                 return NULL;
 590         }
 591
 592         // Ready for symbol use
 593         AddLoaded( Filename, Base );
 594
 595         // Second pass on dynamic table
 596         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 597         {
 598                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 599                 switch(dyntab[i].d_tag)
 600                 {
 601                 case DT_SONAME: break;
 602
 603                 case DT_NEEDED: {
 604                         char *libPath = strtab + dyntab[i].d_un.d_val;
 605                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 606                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 607                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 608                                 return NULL;
 609                         }
 610                         } break;
 611
 612                 // Relocation entries
 613                 case DT_REL:
 614                         dyntab[i].d_un.d_ptr += baseDiff;
 615                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 616                         break;
 617                 case DT_RELSZ:
 618                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 619                         break;
 620                 case DT_RELENT:
 621                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 622                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 623                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 624                                 return NULL;
 625                         }
 626                         break;
 627                 case DT_RELA:
 628                         dyntab[i].d_un.d_ptr += baseDiff;
 629                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 630                         break;
 631                 case DT_RELASZ:
 632                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 633                         break;
 634                 case DT_RELAENT:
 635                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 636                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 637                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 638                                 return NULL;
 639                         }
 640                         break;
 641                 case DT_JMPREL:
 642                         dyntab[i].d_un.d_ptr += baseDiff;
 643                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 644                         break;
 645                 case DT_PLTREL:
 646                         plt_type = dyntab[i].d_un.d_val;
 647                         break;
 648                 case DT_PLTRELSZ:
 649                         plt_size = dyntab[i].d_un.d_val;
 650                         break;
 651                 }
 652         }
 653
 654         // Relocation function
 655         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 656         {
 657                  int    sym = ELF64_R_SYM(r_info);
 658                  int    type = ELF64_R_TYPE(r_info);
 659                 const char      *symname = strtab + symtab[sym].st_name;
 660                 switch( type )
 661                 {
 662                 case R_X86_64_NONE:
 663                         break;
 664                 case R_X86_64_64:
 665                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL) + addend;
 666                         break;
 667                 case R_X86_64_COPY: {
 668                         size_t  size;
 669                         void    *sym = GetSymbol(symname, &size);
 670                         memcpy(ptr, sym, size);
 671                         } break;
 672                 case R_X86_64_GLOB_DAT:
 673                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 674                         break;
 675                 case R_X86_64_JUMP_SLOT:
 676                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 677                         break;
 678                 case R_X86_64_RELATIVE:
 679                         *(uint64_t*)ptr = (uintptr_t)Base + addend;
 680                         break;
 681                 default:
 682                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 683                         break;
 684                 }
 685         }
 686
 687         if( rel )
 688         {
 689                 DEBUGS("rel_count = %i", rel_count);
 690                 for( i = 0; i < rel_count; i ++ )
 691                 {
 692                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 693                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 694                 }
 695         }
 696
 697         if( rela )
 698         {
 699                 DEBUGS("rela_count = %i", rela_count);
 700                 for( i = 0; i < rela_count; i ++ )
 701                 {
 702                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 703                         _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 704                 }
 705         }
 706
 707         if( pltrel && plt_type )
 708         {
 709                 if( plt_type == DT_REL ) {
 710                         Elf64_Rel       *plt = pltrel;
 711                          int    count = plt_size / sizeof(Elf64_Rel);
 712                         DEBUGS("plt rel count = %i", count);
 713                         for( i = 0; i < count; i ++ )
 714                         {
 715                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 716                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 717                         }
 718                 }
 719                 else {
 720                         Elf64_Rela      *plt = pltrel;
 721                          int    count = plt_size / sizeof(Elf64_Rela);
 722                         DEBUGS("plt rela count = %i", count);
 723                         for( i = 0; i < count; i ++ )
 724                         {
 725                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 726                                 _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 727                         }
 728                 }
 729         }
 730
 731         {
 732         void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 733         DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
 734         return ret;
 735         }
 736 }
 737
 738 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 739 {
 740         Elf64_Ehdr      *hdr = Base;
 741         Elf64_Sym       *symtab;
 742          int    nbuckets = 0;
 743 //       int    iSymCount = 0;
 744          int    i;
 745         Elf64_Word      *pBuckets;
 746         Elf64_Word      *pChains;
 747         uint32_t        iNameHash;
 748         const char      *dynstrtab;
 749         uintptr_t       iBaseDiff = -1;
 750
 751         dynstrtab = NULL;
 752         pBuckets = NULL;
 753         symtab = NULL;
 754
 755         // Catch the current executable
 756         if( !pBuckets )
 757         {
 758                 Elf64_Phdr      *phtab;
 759                 Elf64_Dyn       *dynTab = NULL;
 760                  int    j;
 761
 762                 // Locate the tables
 763                 phtab = (void*)( (intptr_t)Base + hdr->e_phoff );
 764                 for( i = 0; i < hdr->e_phnum; i ++ )
 765                 {
 766                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 767                                 iBaseDiff = phtab[i].p_vaddr;
 768                         if( phtab[i].p_type == PT_DYNAMIC ) {
 769                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 770                         }
 771                 }
 772                 if( !dynTab ) {
 773                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 774                         return 0;
 775                 }
 776                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 777                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 778
 779                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 780                 {
 781                         switch(dynTab[j].d_tag)
 782                         {
 783                         // --- Symbol Table ---
 784                         case DT_SYMTAB:
 785                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 786                                 break;
 787                         case DT_STRTAB:
 788                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 789                                 break;
 790                         // --- Hash Table --
 791                         case DT_HASH:
 792                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 793                                 break;
 794                         }
 795                 }
 796         }
 797
 798         nbuckets = pBuckets[0];
 799 //      iSymCount = pBuckets[1];
 800         pBuckets = &pBuckets[2];
 801         pChains = &pBuckets[ nbuckets ];
 802
 803         // Get hash
 804         iNameHash = ElfHashString(Name);
 805         iNameHash %= nbuckets;
 806
 807         // Walk Chain
 808         i = pBuckets[ iNameHash ];
 809         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 810                 *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
 811                 if(Size)        *Size = symtab[i].st_size;
 812                 DEBUGS("%s = %p", Name, *Ret);
 813                 return 1;
 814         }
 815
 816         while(pChains[i] != STN_UNDEF)
 817         {
 818                 i = pChains[i];
 819                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 820                         *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
 821                         if(Size)        *Size = symtab[i].st_size;
 822                         DEBUGS("%s = %p", Name, *Ret);
 823                         return 1;
 824                 }
 825         }
 826
 827         return 0;
 828 }
 829 #endif
 830
 831
 832 uint32_t ElfHashString(const char *name)
 833 {
 834         uint32_t        h = 0, g;
 835         while(*name)
 836         {
 837                 h = (h << 4) + *(uint8_t*)name++;
 838                 if( (g = h & 0xf0000000) )
 839                         h ^= g >> 24;
 840                 h &= ~g;
 841         }
 842         return h;
 843 }
 844