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