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