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                 case R_ARM_COPY: {
 311                         size_t  size;
 312                         void    *src = GetSymbol(Sym, &size);
 313                         DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size);
 314                         memcpy(ptr, src, size);
 315                         break; }
 316                 default:
 317                         SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 318                         break;
 319                 }
 320         }
 321
 322         void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend)
 323         {
 324                  int    type = ELF32_R_TYPE(r_info);
 325                  int    sym = ELF32_R_SYM(r_info);
 326                 const char      *symname = dynstrtab + dynsymtab[sym].nameOfs;
 327                 do_relocate(r_info, ptr, addend, type, bRela, symname);
 328         }
 329
 330         switch(hdr->machine)
 331         {
 332         case EM_386:
 333                 do_relocate = elf_doRelocate_386;
 334                 break;
 335         case EM_ARM:
 336                 do_relocate = elf_doRelocate_arm;
 337                 break;
 338         default:
 339                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 340                 break;
 341         }
 342
 343         // Parse Relocation Entries
 344         if(rel && relSz)
 345         {
 346                 Elf32_Word      *ptr;
 347                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 348                 j = relSz / relEntSz;
 349                 for( i = 0; i < j; i++ )
 350                 {
 351                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 352                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 353                         _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 354                 }
 355         }
 356         // Parse Relocation Entries
 357         if(rela && relaSz)
 358         {
 359                 Elf32_Word      *ptr;
 360                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 361                 j = relaSz / relaEntSz;
 362                 for( i = 0; i < j; i++ )
 363                 {
 364                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 365                         _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 366                 }
 367         }
 368
 369         // === Process PLT (Procedure Linkage Table) ===
 370         if(plt && pltSz)
 371         {
 372                 Elf32_Word      *ptr;
 373                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 374                 if(pltType == DT_REL)
 375                 {
 376                         Elf32_Rel       *pltRel = plt;
 377                         j = pltSz / sizeof(Elf32_Rel);
 378                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 379                         for(i=0;i<j;i++)
 380                         {
 381                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 382                                 _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 383                         }
 384                 }
 385                 else
 386                 {
 387                         Elf32_Rela      *pltRela = plt;
 388                         j = pltSz / sizeof(Elf32_Rela);
 389                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 390                         for(i=0;i<j;i++)
 391                         {
 392                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 393                                 _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 394                         }
 395                 }
 396         }
 397
 398         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 399         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 400 }
 401
 402 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 403 {
 404         Elf32_Ehdr      *hdr = Base;
 405         Elf32_Sym       *symtab;
 406          int    nbuckets = 0;
 407 //       int    iSymCount = 0;
 408          int    i;
 409         Elf32_Word      *pBuckets;
 410         Elf32_Word      *pChains;
 411         uint32_t        iNameHash;
 412         const char      *dynstrtab;
 413         uintptr_t       iBaseDiff = -1;
 414         Elf32_Phdr      *phtab;
 415         Elf32_Dyn       *dynTab = NULL;
 416
 417         // Locate the tables
 418         phtab = (void*)( Base + hdr->phoff );
 419         for( i = 0; i < hdr->phentcount; i ++ )
 420         {
 421                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 422                         iBaseDiff = phtab[i].VAddr;
 423                 if( phtab[i].Type == PT_DYNAMIC ) {
 424                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 425                 }
 426         }
 427         if( !dynTab ) {
 428                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 429                 return 0;
 430         }
 431         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 432         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 433         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 434         {
 435                 switch(dynTab[i].d_tag)
 436                 {
 437                 // --- Symbol Table ---
 438                 case DT_SYMTAB:
 439                         symtab = (void*)(intptr_t) dynTab[i].d_val;     // Rebased in Relocate
 440                         break;
 441                 case DT_STRTAB:
 442                         dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
 443                         break;
 444                 // --- Hash Table --
 445                 case DT_HASH:
 446                         pBuckets = (void*)(intptr_t) dynTab[i].d_val;
 447                         break;
 448                 }
 449         }
 450
 451         nbuckets = pBuckets[0];
 452 //      iSymCount = pBuckets[1];
 453         pBuckets = &pBuckets[2];
 454         pChains = &pBuckets[ nbuckets ];
 455
 456         // Get hash
 457         iNameHash = ElfHashString(Name);
 458         iNameHash %= nbuckets;
 459
 460         // Walk Chain
 461         i = pBuckets[ iNameHash ];
 462         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 463                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 464                 if(Size)        *Size = symtab[i].size;
 465                 return 1;
 466         }
 467
 468         while(pChains[i] != STN_UNDEF)
 469         {
 470                 i = pChains[i];
 471                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 472                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 473                         if(Size)        *Size = symtab[i].size;
 474                         return 1;
 475                 }
 476         }
 477
 478         return 0;
 479 }
 480
 481 #ifdef SUPPORT_ELF64
 482 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 483 {
 484          int    i;
 485         Elf64_Ehdr      *hdr = Base;
 486         Elf64_Phdr      *phtab;
 487         Elf64_Dyn       *dyntab;
 488         Elf64_Addr      compiledBase = -1, baseDiff;
 489         Elf64_Sym       *symtab = NULL;
 490         char    *strtab = NULL;
 491         Elf64_Word      *hashtab = NULL;
 492         Elf64_Rel       *rel = NULL;
 493          int    rel_count = 0;
 494         Elf64_Rela      *rela = NULL;
 495          int    rela_count = 0;
 496         void    *pltrel = NULL;
 497          int    plt_size = 0, plt_type = 0;
 498
 499         DEBUGS("Elf64Relocate: hdr = {");
 500         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 501         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 502         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 503         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 504         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 505         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 506         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 507         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 508         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 509         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 510         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 511
 512         // Scan for the dynamic table (and find the compiled base)
 513         phtab = Base + hdr->e_phoff;
 514         for( i = 0; i < hdr->e_phnum; i ++ )
 515         {
 516                 if(phtab[i].p_type == PT_DYNAMIC)
 517                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 518                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 519                         compiledBase = phtab[i].p_vaddr;
 520         }
 521
 522         baseDiff = (uintptr_t)Base - compiledBase;
 523
 524         DEBUGS("baseDiff = %p", baseDiff);
 525
 526         if(dyntab == NULL) {
 527                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 528                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 529         }
 530
 531         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 532
 533         // Parse the dynamic table (first pass)
 534         // - Search for String, Symbol and Hash tables
 535         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 536         {
 537                 switch(dyntab[i].d_tag)
 538                 {
 539                 case DT_SYMTAB:
 540                         dyntab[i].d_un.d_ptr += baseDiff;
 541                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 542                         break;
 543                 case DT_STRTAB:
 544                         dyntab[i].d_un.d_ptr += baseDiff;
 545                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 546                         break;
 547                 case DT_HASH:
 548                         dyntab[i].d_un.d_ptr += baseDiff;
 549                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 550                         break;
 551                 }
 552         }
 553
 554         if( !symtab || !strtab || !hashtab ) {
 555                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 556                 return NULL;
 557         }
 558
 559         // Ready for symbol use
 560         AddLoaded( Filename, Base );
 561
 562         // Second pass on dynamic table
 563         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 564         {
 565                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 566                 switch(dyntab[i].d_tag)
 567                 {
 568                 case DT_SONAME: break;
 569
 570                 case DT_NEEDED: {
 571                         char *libPath = strtab + dyntab[i].d_un.d_val;
 572                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 573                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 574                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 575                                 return NULL;
 576                         }
 577                         } break;
 578
 579                 // Relocation entries
 580                 case DT_REL:
 581                         dyntab[i].d_un.d_ptr += baseDiff;
 582                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 583                         break;
 584                 case DT_RELSZ:
 585                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 586                         break;
 587                 case DT_RELENT:
 588                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 589                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 590                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 591                                 return NULL;
 592                         }
 593                         break;
 594                 case DT_RELA:
 595                         dyntab[i].d_un.d_ptr += baseDiff;
 596                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 597                         break;
 598                 case DT_RELASZ:
 599                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 600                         break;
 601                 case DT_RELAENT:
 602                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 603                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 604                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 605                                 return NULL;
 606                         }
 607                         break;
 608                 case DT_JMPREL:
 609                         dyntab[i].d_un.d_ptr += baseDiff;
 610                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 611                         break;
 612                 case DT_PLTREL:
 613                         plt_type = dyntab[i].d_un.d_val;
 614                         break;
 615                 case DT_PLTRELSZ:
 616                         plt_size = dyntab[i].d_un.d_val;
 617                         break;
 618                 }
 619         }
 620
 621         // Relocation function
 622         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 623         {
 624                  int    sym = ELF64_R_SYM(r_info);
 625                  int    type = ELF64_R_TYPE(r_info);
 626                 const char      *symname = strtab + symtab[sym].st_name;
 627                 switch( type )
 628                 {
 629                 case R_X86_64_NONE:
 630                         break;
 631                 case R_X86_64_64:
 632                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL) + addend;
 633                         break;
 634                 case R_X86_64_COPY: {
 635                         size_t  size;
 636                         void    *sym = GetSymbol(symname, &size);
 637                         memcpy(ptr, sym, size);
 638                         } break;
 639                 case R_X86_64_GLOB_DAT:
 640                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 641                         break;
 642                 case R_X86_64_JUMP_SLOT:
 643                         *(uint64_t*)ptr = (uintptr_t)GetSymbol(symname, NULL);
 644                         break;
 645                 case R_X86_64_RELATIVE:
 646                         *(uint64_t*)ptr = (uintptr_t)Base + addend;
 647                         break;
 648                 default:
 649                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 650                         break;
 651                 }
 652         }
 653
 654         if( rel )
 655         {
 656                 DEBUGS("rel_count = %i", rel_count);
 657                 for( i = 0; i < rel_count; i ++ )
 658                 {
 659                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 660                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 661                 }
 662         }
 663
 664         if( rela )
 665         {
 666                 DEBUGS("rela_count = %i", rela_count);
 667                 for( i = 0; i < rela_count; i ++ )
 668                 {
 669                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 670                         _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 671                 }
 672         }
 673
 674         if( pltrel && plt_type )
 675         {
 676                 if( plt_type == DT_REL ) {
 677                         Elf64_Rel       *plt = pltrel;
 678                          int    count = plt_size / sizeof(Elf64_Rel);
 679                         DEBUGS("plt rel count = %i", count);
 680                         for( i = 0; i < count; i ++ )
 681                         {
 682                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 683                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 684                         }
 685                 }
 686                 else {
 687                         Elf64_Rela      *plt = pltrel;
 688                          int    count = plt_size / sizeof(Elf64_Rela);
 689                         DEBUGS("plt rela count = %i", count);
 690                         for( i = 0; i < count; i ++ )
 691                         {
 692                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 693                                 _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 694                         }
 695                 }
 696         }
 697
 698         {
 699         void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 700         DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
 701         return ret;
 702         }
 703 }
 704
 705 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 706 {
 707         Elf64_Ehdr      *hdr = Base;
 708         Elf64_Sym       *symtab;
 709          int    nbuckets = 0;
 710 //       int    iSymCount = 0;
 711          int    i;
 712         Elf64_Word      *pBuckets;
 713         Elf64_Word      *pChains;
 714         uint32_t        iNameHash;
 715         const char      *dynstrtab;
 716         uintptr_t       iBaseDiff = -1;
 717
 718         dynstrtab = NULL;
 719         pBuckets = NULL;
 720         symtab = NULL;
 721
 722         // Catch the current executable
 723         if( !pBuckets )
 724         {
 725                 Elf64_Phdr      *phtab;
 726                 Elf64_Dyn       *dynTab = NULL;
 727                  int    j;
 728
 729                 // Locate the tables
 730                 phtab = (void*)( Base + hdr->e_phoff );
 731                 for( i = 0; i < hdr->e_phnum; i ++ )
 732                 {
 733                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 734                                 iBaseDiff = phtab[i].p_vaddr;
 735                         if( phtab[i].p_type == PT_DYNAMIC ) {
 736                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 737                         }
 738                 }
 739                 if( !dynTab ) {
 740                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 741                         return 0;
 742                 }
 743                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 744                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 745
 746                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 747                 {
 748                         switch(dynTab[j].d_tag)
 749                         {
 750                         // --- Symbol Table ---
 751                         case DT_SYMTAB:
 752                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 753                                 break;
 754                         case DT_STRTAB:
 755                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 756                                 break;
 757                         // --- Hash Table --
 758                         case DT_HASH:
 759                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 760                                 break;
 761                         }
 762                 }
 763         }
 764
 765         nbuckets = pBuckets[0];
 766 //      iSymCount = pBuckets[1];
 767         pBuckets = &pBuckets[2];
 768         pChains = &pBuckets[ nbuckets ];
 769
 770         // Get hash
 771         iNameHash = ElfHashString(Name);
 772         iNameHash %= nbuckets;
 773
 774         // Walk Chain
 775         i = pBuckets[ iNameHash ];
 776         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 777                 *Ret = (void*) (intptr_t) symtab[i].st_value + iBaseDiff;
 778                 if(Size)        *Size = symtab[i].st_size;
 779                 DEBUGS("%s = %p", Name, *Ret);
 780                 return 1;
 781         }
 782
 783         while(pChains[i] != STN_UNDEF)
 784         {
 785                 i = pChains[i];
 786                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 787                         *Ret = (void*)(intptr_t)symtab[i].st_value + iBaseDiff;
 788                         if(Size)        *Size = symtab[i].st_size;
 789                         DEBUGS("%s = %p", Name, *Ret);
 790                         return 1;
 791                 }
 792         }
 793
 794         return 0;
 795 }
 796 #endif
 797
 798
 799 uint32_t ElfHashString(const char *name)
 800 {
 801         uint32_t        h = 0, g;
 802         while(*name)
 803         {
 804                 h = (h << 4) + *(uint8_t*)name++;
 805                 if( (g = h & 0xf0000000) )
 806                         h ^= g >> 24;
 807                 h &= ~g;
 808         }
 809         return h;
 810 }
 811