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 #ifndef DEBUG   // This code is #include'd from the kernel, so DEBUG may already be defined
   9 # define DEBUG  0
  10 #endif
  11
  12 #ifndef PAGE_SIZE
  13 # define PAGE_SIZE      4096
  14 #endif
  15
  16 #include "common.h"
  17 #include <stdint.h>
  18 #include "elf32.h"
  19 #include "elf64.h"
  20
  21 #if DEBUG
  22 # define        DEBUGS(v...)    SysDebug("ld-acess - " v)
  23 #else
  24 # define        DEBUGS(...)
  25 #endif
  26
  27 #ifndef DISABLE_ELF64
  28 # define SUPPORT_ELF64
  29 #endif
  30
  31 // === CONSTANTS ===
  32 #if DEBUG
  33 //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"};
  34 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"};
  35 #endif
  36
  37 // === PROTOTYPES ===
  38 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  39  int    ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  40 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  41  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  42  int    elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  43  int    elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  44  int    elf_doRelocate_unk(uint32_t , uint32_t *, Elf32_Addr , int , int , const char *, intptr_t);
  45 #ifdef SUPPORT_ELF64
  46 int     _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
  47 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  48  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  49 #endif
  50 uint32_t        ElfHashString(const char *name);
  51
  52 // === CODE ===
  53 /**
  54  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  55  * \brief Relocates a loaded ELF Executable
  56  */
  57 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  58 {
  59         Elf32_Ehdr      *hdr = Base;
  60
  61         switch(hdr->e_ident[4])
  62         {
  63         case ELFCLASS32:
  64                 return Elf32Relocate(Base, envp, Filename);
  65 #ifdef SUPPORT_ELF64
  66         case ELFCLASS64:
  67                 return Elf64Relocate(Base, envp, Filename);
  68 #endif
  69         default:
  70                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  71                 return NULL;
  72         }
  73 }
  74
  75 /**
  76  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  77  */
  78 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  79 {
  80         Elf32_Ehdr      *hdr = Base;
  81
  82         switch(hdr->e_ident[4])
  83         {
  84         case ELFCLASS32:
  85                 return Elf32GetSymbol(Base, Name, ret, Size);
  86 #ifdef SUPPORT_ELF64
  87         case ELFCLASS64:
  88                 return Elf64GetSymbol(Base, Name, ret, Size);
  89 #endif
  90         default:
  91                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  92                 return 0;
  93         }
  94 }
  95
  96 int elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type,
  97                 int bRela, const char *Sym, intptr_t iBaseDiff)
  98 {
  99         void    *symval;
 100         switch( type )
 101         {
 102         // Standard 32 Bit Relocation (S+A)
 103         case R_386_32:
 104                 if( !GetSymbol(Sym, &symval, NULL) )
 105                         return 1;
 106                 DEBUGS(" elf_doRelocate: R_386_32 *0x%x += %p('%s')",
 107                                 ptr, symval, Sym);
 108                 *ptr = (intptr_t)symval + addend;
 109                 break;
 110
 111         // 32 Bit Relocation wrt. Offset (S+A-P)
 112         case R_386_PC32:
 113                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 114                 if( !GetSymbol(Sym, &symval, NULL) )    return 1;
 115                 DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%p - 0x%x",
 116                         ptr, *ptr, symval, (intptr_t)ptr );
 117                 *ptr = (intptr_t)symval + addend - (intptr_t)ptr;
 118                 //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 119                 break;
 120
 121         // Absolute Value of a symbol (S)
 122         case R_386_GLOB_DAT:
 123         case R_386_JMP_SLOT:
 124                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 125                 if( !GetSymbol(Sym, &symval, NULL) )    return 1;
 126                 DEBUGS(" elf_doRelocate: %s *0x%x = %p", csaR_NAMES[type], ptr, symval);
 127                 *ptr = (intptr_t)symval;
 128                 break;
 129
 130         // Base Address (B+A)
 131         case R_386_RELATIVE:
 132                 DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 133                 *ptr = iBaseDiff + addend;
 134                 break;
 135
 136         case R_386_COPY: {
 137                 size_t  size;
 138                 if( !GetSymbol(Sym, &symval, &size) )   return 1;
 139                 DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, symval, size);
 140                 memcpy(ptr, symval, size);
 141                 break; }
 142
 143         default:
 144                 SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 145                 return 2;
 146         }
 147         return 0;
 148 }
 149
 150 int elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
 151 {
 152         uint32_t        val;
 153         switch(type)
 154         {
 155         // (S + A) | T
 156         case R_ARM_ABS32:
 157                 DEBUGS(" elf_doRelocate_arm: R_ARM_ABS32 %p (%s + %x)", ptr, Sym, addend);
 158                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 159                 *ptr = val + addend;
 160                 break;
 161         case R_ARM_GLOB_DAT:
 162                 DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
 163                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 164                 *ptr = val + addend;
 165                 break;
 166         case R_ARM_JUMP_SLOT:
 167                 if(!bRela)      addend = 0;
 168                 DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
 169                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 170                 *ptr = val + addend;
 171                 break;
 172         // Copy
 173         case R_ARM_COPY: {
 174                 size_t  size;
 175                 void    *src;
 176                 if( !GetSymbol(Sym, &src, &size) )      return 1;
 177                 DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size);
 178                 memcpy(ptr, src, size);
 179                 break; }
 180         // Delta between link and runtime locations + A
 181         case R_ARM_RELATIVE:
 182                 DEBUGS(" elf_doRelocate_arm: R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, iBaseDiff, addend);
 183                 if(Sym[0] != '\0') {
 184                         // TODO: Get delta for a symbol
 185                         SysDebug("elf_doRelocate_arm: TODO - Implment R_ARM_RELATIVE for symbols");
 186                         return 2;
 187                 }
 188                 else {
 189                         *ptr = iBaseDiff + addend;
 190                 }
 191                 break;
 192         default:
 193                 SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 194                 return 2;
 195         }
 196         return 0;
 197 }
 198
 199 int elf_doRelocate_unk(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
 200 {
 201         return 1;
 202 }
 203
 204 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 205 {
 206         Elf32_Ehdr      *hdr = Base;
 207         Elf32_Phdr      *phtab;
 208         char    *libPath;
 209         intptr_t        iRealBase = -1;
 210         intptr_t        iBaseDiff;
 211          int    iSegmentCount;
 212         Elf32_Rel       *rel = NULL;
 213         Elf32_Rela      *rela = NULL;
 214         void    *plt = NULL;
 215          int    relSz=0, relEntSz=8;
 216          int    relaSz=0, relaEntSz=8;
 217          int    pltSz=0, pltType=0;
 218         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 219         char    *dynstrtab = NULL;      // .dynamic String Table
 220         Elf32_Sym       *dynsymtab;
 221         int     (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym, intptr_t iBaseDiff);
 222
 223         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 224
 225         // Check magic header
 226
 227
 228         // Parse Program Header to get Dynamic Table
 229         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 230         iSegmentCount = hdr->phentcount;
 231         for(int i = 0; i < iSegmentCount; i ++)
 232         {
 233                 switch(phtab[i].Type)
 234                 {
 235                 case PT_LOAD:
 236                         // Determine linked base address
 237                         if( iRealBase > phtab[i].VAddr)
 238                                 iRealBase = phtab[i].VAddr;
 239                         break;
 240                 case PT_DYNAMIC:
 241                         // Find Dynamic Section
 242                         if(!dynamicTab) {
 243                                 dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 244                         }
 245                         else {
 246                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 247                         }
 248                         break;
 249                 }
 250         }
 251
 252         // Page Align real base
 253         iRealBase &= ~0xFFF;
 254         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 255
 256         // Adjust "Real" Base
 257         iBaseDiff = (intptr_t)Base - iRealBase;
 258
 259 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 260
 261         // Check if a PT_DYNAMIC segement was found
 262         if(!dynamicTab) {
 263                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 264                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 265         }
 266
 267         // Allow writing to read-only segments, just in case they need to be relocated
 268         // - Will be reversed at the end of the function
 269         for( int i = 0; i < iSegmentCount; i ++ )
 270         {
 271                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 272                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 273                         uintptr_t       end = addr + phtab[i].MemSize;
 274                         for( ; addr < end; addr += PAGE_SIZE )
 275                                 _SysSetMemFlags(addr, 0, 1);    // Unset RO
 276                 }
 277         }
 278
 279         // Adjust Dynamic Table
 280         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 281
 282         // === Get Symbol table and String Table ===
 283         dynsymtab = NULL;
 284         for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 285         {
 286                 switch(dynamicTab[j].d_tag)
 287                 {
 288                 // --- Symbol Table ---
 289                 case DT_SYMTAB:
 290                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 291                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 292                         dynsymtab = (void*)((intptr_t)dynamicTab[j].d_val + iBaseDiff);
 293                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 294                         break;
 295                 // --- String Table ---
 296                 case DT_STRTAB:
 297                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 298                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 299                         dynstrtab = (void*)((intptr_t)dynamicTab[j].d_val + iBaseDiff);
 300                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 301                         break;
 302                 // --- Hash Table --
 303                 case DT_HASH:
 304                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 305 //                      iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
 306                         break;
 307                 }
 308         }
 309
 310         if(dynsymtab == NULL) {
 311                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 312                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 313         }
 314
 315         // === Add to loaded list (can be imported now) ===
 316         AddLoaded( Filename, Base );
 317
 318         // === Parse Relocation Data ===
 319         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 320         for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 321         {
 322                 switch(dynamicTab[j].d_tag)
 323                 {
 324                 // --- Shared Library Name ---
 325                 case DT_SONAME:
 326                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 327                         break;
 328                 // --- Needed Library ---
 329                 case DT_NEEDED:
 330                         libPath = dynstrtab + dynamicTab[j].d_val;
 331                         DEBUGS(" dynstrtab = %p, d_val = 0x%x", dynstrtab, dynamicTab[j].d_val);
 332                         DEBUGS(" Required Library '%s'", libPath);
 333                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 334                                 #if DEBUG
 335                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 336                                 #else
 337                                 SysDebug("Unable to load required library '%s'", libPath);
 338                                 #endif
 339                                 return 0;
 340                         }
 341                         DEBUGS(" Lib loaded");
 342                         break;
 343                 // --- PLT/GOT ---
 344 //              case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 345                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 346                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 347                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 348
 349                 // --- Relocation ---
 350                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 351                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 352                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 353                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 354                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 355                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 356
 357                 // --- Symbol Table ---
 358                 case DT_SYMTAB:
 359                 // --- Hash Table ---
 360                 case DT_HASH:
 361                 // --- String Table ---
 362                 case DT_STRTAB:
 363                         break;
 364
 365                 // --- Unknown ---
 366                 default:
 367                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 368                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 369                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 370                         break;
 371                 }
 372         }
 373
 374         DEBUGS(" elf_relocate: Beginning Relocation");
 375
 376          int    fail = 0;
 377
 378         switch(hdr->machine)
 379         {
 380         case EM_386:
 381                 do_relocate = elf_doRelocate_386;
 382                 break;
 383         case EM_ARM:
 384                 do_relocate = elf_doRelocate_arm;
 385                 break;
 386         default:
 387                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 388                 do_relocate = elf_doRelocate_unk;
 389                 fail = 1;
 390                 break;
 391         }
 392
 393         DEBUGS("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
 394
 395         #define _doRelocate(r_info, ptr, bRela, addend) \
 396                 do_relocate(r_info, ptr, addend, ELF32_R_TYPE(r_info), bRela, \
 397                         dynstrtab + dynsymtab[ELF32_R_SYM(r_info)].nameOfs, iBaseDiff);
 398
 399         // Parse Relocation Entries
 400         if(rel && relSz)
 401         {
 402                 Elf32_Word      *ptr;
 403                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 404                 int max = relSz / relEntSz;
 405                 for( int i = 0; i < max; i++ )
 406                 {
 407                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 408                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 409                         fail |= _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 410                 }
 411         }
 412         // Parse Relocation Entries
 413         if(rela && relaSz)
 414         {
 415                 Elf32_Word      *ptr;
 416                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 417                 int count = relaSz / relaEntSz;
 418                 for( int i = 0; i < count; i++ )
 419                 {
 420                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 421                         fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 422                 }
 423         }
 424
 425         // === Process PLT (Procedure Linkage Table) ===
 426         if(plt && pltSz)
 427         {
 428                 Elf32_Word      *ptr;
 429                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 430                 if(pltType == DT_REL)
 431                 {
 432                         Elf32_Rel       *pltRel = plt;
 433                         int count = pltSz / sizeof(Elf32_Rel);
 434                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", count);
 435                         for(int i = 0; i < count; i ++)
 436                         {
 437                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 438                                 fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 439                         }
 440                 }
 441                 else
 442                 {
 443                         Elf32_Rela      *pltRela = plt;
 444                         int count = pltSz / sizeof(Elf32_Rela);
 445                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", count);
 446                         for(int i=0;i<count;i++)
 447                         {
 448                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 449                                 fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 450                         }
 451                 }
 452         }
 453
 454         // Re-set readonly
 455         for( int i = 0; i < iSegmentCount; i ++ )
 456         {
 457                 // If load and not writable
 458                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 459                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 460                         uintptr_t       end = addr + phtab[i].MemSize;
 461                         for( ; addr < end; addr += PAGE_SIZE )
 462                                 _SysSetMemFlags(addr, 1, 1);    // Unset RO
 463                 }
 464         }
 465
 466         if( fail ) {
 467                 DEBUGS("ElfRelocate: Failure");
 468                 return NULL;
 469         }
 470
 471         #undef _doRelocate
 472
 473         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 474         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 475 }
 476
 477 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 478 {
 479         Elf32_Ehdr      *hdr = Base;
 480         Elf32_Sym       *symtab = NULL;
 481          int    nbuckets = 0;
 482         Elf32_Word      *pBuckets = NULL;
 483         Elf32_Word      *pChains;
 484         uint32_t        iNameHash;
 485         const char      *dynstrtab = NULL;
 486         uintptr_t       iBaseDiff = -1;
 487         Elf32_Phdr      *phtab;
 488         Elf32_Dyn       *dynTab = NULL;
 489
 490         // Locate the tables
 491         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 492         for( int i = 0; i < hdr->phentcount; i ++ )
 493         {
 494                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 495                         iBaseDiff = phtab[i].VAddr;
 496                 if( phtab[i].Type == PT_DYNAMIC ) {
 497                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 498                 }
 499         }
 500         if( !dynTab ) {
 501                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 502                 return 0;
 503         }
 504         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 505         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 506         for( int i = 0; dynTab[i].d_tag != DT_NULL; i++)
 507         {
 508                 switch(dynTab[i].d_tag)
 509                 {
 510                 // --- Symbol Table ---
 511                 case DT_SYMTAB:
 512                         symtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);        // Rebased in Relocate
 513                         break;
 514                 case DT_STRTAB:
 515                         dynstrtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 516                         break;
 517                 // --- Hash Table --
 518                 case DT_HASH:
 519                         pBuckets = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 520                         break;
 521                 }
 522         }
 523
 524         if( !symtab ) {
 525                 SysDebug("ERRO - No DT_SYMTAB in %p", Base);
 526                 return 0;
 527         }
 528         if( !pBuckets ) {
 529                 SysDebug("ERRO - No DT_HASH in %p", Base);
 530                 return 0;
 531         }
 532         if( !dynstrtab ) {
 533                 SysDebug("ERRO - No DT_STRTAB in %p", Base);
 534                 return 0;
 535         }
 536
 537         // ... ok... maybe they haven't been relocated
 538         if( (uintptr_t)symtab < (uintptr_t)Base )
 539         {
 540                 symtab    = (void*)( (uintptr_t)symtab    + iBaseDiff );
 541                 pBuckets  = (void*)( (uintptr_t)pBuckets  + iBaseDiff );
 542                 dynstrtab = (void*)( (uintptr_t)dynstrtab + iBaseDiff );
 543                 SysDebug("Executable not yet relocated");
 544         }
 545
 546         nbuckets = pBuckets[0];
 547 //      iSymCount = pBuckets[1];
 548         pBuckets = &pBuckets[2];
 549         pChains = &pBuckets[ nbuckets ];
 550         assert(pChains);
 551
 552         // Get hash
 553         iNameHash = ElfHashString(Name);
 554         iNameHash %= nbuckets;
 555
 556         // Walk Chain
 557         int idx = pBuckets[ iNameHash ];
 558         do {
 559                 Elf32_Sym *sym = &symtab[idx];
 560                 assert(sym);
 561                 if(sym->shndx != SHN_UNDEF && strcmp(dynstrtab + sym->nameOfs, Name) == 0) {
 562                         *ret = (void*)( (uintptr_t)sym->value + iBaseDiff );
 563                         if(Size)        *Size = sym->size;
 564                         return 1;
 565                 }
 566         } while( (idx = pChains[idx]) != STN_UNDEF && idx != pBuckets[iNameHash] );
 567
 568         return 0;
 569 }
 570
 571 #ifdef SUPPORT_ELF64
 572 typedef int (*t_elf64_doreloc)(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
 573
 574 int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 575 {
 576          int    sym = ELF64_R_SYM(r_info);
 577          int    type = ELF64_R_TYPE(r_info);
 578         const char      *symname = strtab + symtab[sym].st_name;
 579         void    *symval;
 580         //DEBUGS("_Elf64DoReloc: %s", symname);
 581         switch( type )
 582         {
 583         case R_X86_64_NONE:
 584                 break;
 585         case R_X86_64_64:
 586                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 587                 *(uint64_t*)ptr = (uintptr_t)symval + addend;
 588                 break;
 589         case R_X86_64_COPY: {
 590                 size_t  size;
 591                 if( !GetSymbol(symname, &symval, &size)  )      return 1;
 592                 memcpy(ptr, symval, size);
 593                 } break;
 594         case R_X86_64_GLOB_DAT:
 595                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 596                 *(uint64_t*)ptr = (uintptr_t)symval;
 597                 break;
 598         case R_X86_64_JUMP_SLOT:
 599                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 600                 *(uint64_t*)ptr = (uintptr_t)symval;
 601                 break;
 602         case R_X86_64_RELATIVE:
 603                 *(uint64_t*)ptr = (uintptr_t)Base + addend;
 604                 break;
 605         default:
 606                 SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 607                 return 2;
 608         }
 609         //DEBUGS("_Elf64DoReloc: - Good");
 610         return 0;
 611 }
 612
 613 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 614 {
 615          int    i;
 616         Elf64_Ehdr      *hdr = Base;
 617         Elf64_Phdr      *phtab;
 618         Elf64_Dyn       *dyntab = NULL;
 619         Elf64_Addr      compiledBase = -1, baseDiff;
 620         Elf64_Sym       *symtab = NULL;
 621         char    *strtab = NULL;
 622         Elf64_Word      *hashtab = NULL;
 623         Elf64_Rel       *rel = NULL;
 624          int    rel_count = 0;
 625         Elf64_Rela      *rela = NULL;
 626          int    rela_count = 0;
 627         void    *pltrel = NULL;
 628          int    plt_size = 0, plt_type = 0;
 629
 630         DEBUGS("Elf64Relocate: hdr = {");
 631         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 632         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 633         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 634         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 635         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 636         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 637         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 638         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 639         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 640         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 641         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 642
 643         // Scan for the dynamic table (and find the compiled base)
 644         phtab = (void*)((uintptr_t)Base + (uintptr_t)hdr->e_phoff);
 645         for( i = 0; i < hdr->e_phnum; i ++ )
 646         {
 647                 if(phtab[i].p_type == PT_DYNAMIC)
 648                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 649                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 650                         compiledBase = phtab[i].p_vaddr;
 651         }
 652
 653         baseDiff = (uintptr_t)Base - compiledBase;
 654
 655         DEBUGS("baseDiff = %p", baseDiff);
 656
 657         if(dyntab == NULL) {
 658                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 659                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 660         }
 661
 662         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 663
 664         // Parse the dynamic table (first pass)
 665         // - Search for String, Symbol and Hash tables
 666         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 667         {
 668                 switch(dyntab[i].d_tag)
 669                 {
 670                 case DT_SYMTAB:
 671                         dyntab[i].d_un.d_ptr += baseDiff;
 672                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 673                         break;
 674                 case DT_STRTAB:
 675                         dyntab[i].d_un.d_ptr += baseDiff;
 676                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 677                         break;
 678                 case DT_HASH:
 679                         dyntab[i].d_un.d_ptr += baseDiff;
 680                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 681                         break;
 682                 }
 683         }
 684
 685         if( !symtab || !strtab || !hashtab ) {
 686                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 687                 return NULL;
 688         }
 689
 690         // Ready for symbol use
 691         AddLoaded( Filename, Base );
 692
 693         // Second pass on dynamic table
 694         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 695         {
 696                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 697                 switch(dyntab[i].d_tag)
 698                 {
 699                 case DT_SONAME: break;
 700
 701                 case DT_NEEDED: {
 702                         char *libPath = strtab + dyntab[i].d_un.d_val;
 703                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 704                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 705                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 706                                 return NULL;
 707                         }
 708                         } break;
 709
 710                 // Relocation entries
 711                 case DT_REL:
 712                         dyntab[i].d_un.d_ptr += baseDiff;
 713                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 714                         break;
 715                 case DT_RELSZ:
 716                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 717                         break;
 718                 case DT_RELENT:
 719                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 720                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 721                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 722                                 return NULL;
 723                         }
 724                         break;
 725                 case DT_RELA:
 726                         dyntab[i].d_un.d_ptr += baseDiff;
 727                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 728                         break;
 729                 case DT_RELASZ:
 730                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 731                         break;
 732                 case DT_RELAENT:
 733                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 734                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 735                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 736                                 return NULL;
 737                         }
 738                         break;
 739                 case DT_JMPREL:
 740                         dyntab[i].d_un.d_ptr += baseDiff;
 741                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 742                         break;
 743                 case DT_PLTREL:
 744                         plt_type = dyntab[i].d_un.d_val;
 745                         break;
 746                 case DT_PLTRELSZ:
 747                         plt_size = dyntab[i].d_un.d_val;
 748                         break;
 749                 }
 750         }
 751
 752         // Relocation function
 753         t_elf64_doreloc fpElf64DoReloc = &_Elf64DoReloc_X86_64;
 754         #define _Elf64DoReloc(info, ptr, addend)        fpElf64DoReloc(Base, strtab, symtab, info, ptr, addend)
 755
 756         int fail = 0;
 757         if( rel )
 758         {
 759                 DEBUGS("rel_count = %i", rel_count);
 760                 for( i = 0; i < rel_count; i ++ )
 761                 {
 762                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 763                         fail |= _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 764                 }
 765         }
 766
 767         if( rela )
 768         {
 769                 DEBUGS("rela_count = %i", rela_count);
 770                 for( i = 0; i < rela_count; i ++ )
 771                 {
 772                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 773                         fail |= _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 774                 }
 775         }
 776
 777         if( pltrel && plt_type )
 778         {
 779                 if( plt_type == DT_REL ) {
 780                         Elf64_Rel       *plt = pltrel;
 781                          int    count = plt_size / sizeof(Elf64_Rel);
 782                         DEBUGS("plt rel count = %i", count);
 783                         for( i = 0; i < count; i ++ )
 784                         {
 785                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 786                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 787                         }
 788                 }
 789                 else {
 790                         Elf64_Rela      *plt = pltrel;
 791                          int    count = plt_size / sizeof(Elf64_Rela);
 792                         DEBUGS("plt rela count = %i", count);
 793                         for( i = 0; i < count; i ++ )
 794                         {
 795                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 796                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 797                         }
 798                 }
 799         }
 800
 801         if( fail ) {
 802                 DEBUGS("Elf64Relocate: Failure");
 803                 return NULL;
 804         }
 805
 806         {
 807         void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 808         DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
 809         return ret;
 810         }
 811 }
 812
 813 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 814 {
 815         Elf64_Ehdr      *hdr = Base;
 816         Elf64_Sym       *symtab;
 817          int    nbuckets = 0;
 818 //       int    iSymCount = 0;
 819          int    i;
 820         Elf64_Word      *pBuckets;
 821         Elf64_Word      *pChains;
 822         uint32_t        iNameHash;
 823         const char      *dynstrtab;
 824         uintptr_t       iBaseDiff = -1;
 825
 826         dynstrtab = NULL;
 827         pBuckets = NULL;
 828         symtab = NULL;
 829
 830         // Catch the current executable
 831         if( !pBuckets )
 832         {
 833                 Elf64_Phdr      *phtab;
 834                 Elf64_Dyn       *dynTab = NULL;
 835                  int    j;
 836
 837                 // Locate the tables
 838                 phtab = (void*)( (intptr_t)Base + (uintptr_t)hdr->e_phoff );
 839                 for( i = 0; i < hdr->e_phnum; i ++ )
 840                 {
 841                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 842                                 iBaseDiff = phtab[i].p_vaddr;
 843                         if( phtab[i].p_type == PT_DYNAMIC ) {
 844                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 845                         }
 846                 }
 847                 if( !dynTab ) {
 848                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 849                         return 0;
 850                 }
 851                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 852                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 853
 854                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 855                 {
 856                         switch(dynTab[j].d_tag)
 857                         {
 858                         // --- Symbol Table ---
 859                         case DT_SYMTAB:
 860                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 861                                 break;
 862                         case DT_STRTAB:
 863                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 864                                 break;
 865                         // --- Hash Table --
 866                         case DT_HASH:
 867                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 868                                 break;
 869                         }
 870                 }
 871         }
 872
 873         nbuckets = pBuckets[0];
 874 //      iSymCount = pBuckets[1];
 875         pBuckets = &pBuckets[2];
 876         pChains = &pBuckets[ nbuckets ];
 877
 878         // Get hash
 879         iNameHash = ElfHashString(Name);
 880         iNameHash %= nbuckets;
 881
 882         // Walk Chain
 883         i = pBuckets[ iNameHash ];
 884         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 885                 *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
 886                 if(Size)        *Size = symtab[i].st_size;
 887                 DEBUGS("%s = %p", Name, *Ret);
 888                 return 1;
 889         }
 890
 891         while(pChains[i] != STN_UNDEF)
 892         {
 893                 i = pChains[i];
 894                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 895                         *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
 896                         if(Size)        *Size = symtab[i].st_size;
 897                         DEBUGS("%s = %p", Name, *Ret);
 898                         return 1;
 899                 }
 900         }
 901
 902         return 0;
 903 }
 904 #endif
 905
 906
 907 uint32_t ElfHashString(const char *name)
 908 {
 909         uint32_t        h = 0, g;
 910         while(*name)
 911         {
 912                 h = (h << 4) + *(uint8_t*)name++;
 913                 if( (g = h & 0xf0000000) )
 914                         h ^= g >> 24;
 915                 h &= ~g;
 916         }
 917         return h;
 918 }
 919