Usermode/Libraries/ld-acess.so_src/elf.c

   1 /*
   2  * AcessOS 1 - Dynamic Loader
   3  * By thePowersGang
   4  */
   5 #define DEBUG   0
   6
   7 #include "common.h"
   8 #include <stdint.h>
   9 #include "elf32.h"
  10 #include "elf64.h"
  11
  12 #if DEBUG
  13 # define        DEBUGS(v...)    SysDebug("ld-acess - " v)
  14 #else
  15 # define        DEBUGS(...)
  16 #endif
  17
  18 //#if BITS > 32
  19 # define SUPPORT_ELF64
  20 //#endif
  21
  22 // === CONSTANTS ===
  23 #if DEBUG
  24 //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"};
  25 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"};
  26 #endif
  27
  28 // === PROTOTYPES ===
  29 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  30  int    ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  31 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  32  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  33 #ifdef SUPPORT_ELF64
  34 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  35  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  36 #endif
  37 Uint32  ElfHashString(const char *name);
  38
  39 // === CODE ===
  40 /**
  41  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  42  * \brief Relocates a loaded ELF Executable
  43  */
  44 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  45 {
  46         Elf32_Ehdr      *hdr = Base;
  47
  48         switch(hdr->e_ident[4])
  49         {
  50         case ELFCLASS32:
  51                 return Elf32Relocate(Base, envp, Filename);
  52 #ifdef SUPPORT_ELF64
  53         case ELFCLASS64:
  54                 return Elf64Relocate(Base, envp, Filename);
  55 #endif
  56         default:
  57                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  58                 return NULL;
  59         }
  60 }
  61
  62 /**
  63  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  64  */
  65 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  66 {
  67         Elf32_Ehdr      *hdr = Base;
  68
  69         switch(hdr->e_ident[4])
  70         {
  71         case ELFCLASS32:
  72                 return Elf32GetSymbol(Base, Name, ret, Size);
  73 #ifdef SUPPORT_ELF64
  74         case ELFCLASS64:
  75                 return Elf64GetSymbol(Base, Name, ret, Size);
  76 #endif
  77         default:
  78                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  79                 return 0;
  80         }
  81 }
  82
  83 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
  84 {
  85         Elf32_Ehdr      *hdr = Base;
  86         Elf32_Phdr      *phtab;
  87          int    i, j;   // Counters
  88         char    *libPath;
  89         intptr_t        iRealBase = -1;
  90         intptr_t        iBaseDiff;
  91          int    iSegmentCount;
  92          int    iSymCount;
  93         Elf32_Rel       *rel = NULL;
  94         Elf32_Rela      *rela = NULL;
  95         Uint32  *pltgot = NULL;
  96         void    *plt = NULL;
  97          int    relSz=0, relEntSz=8;
  98          int    relaSz=0, relaEntSz=8;
  99          int    pltSz=0, pltType=0;
 100         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 101         char    *dynstrtab = NULL;      // .dynamic String Table
 102         Elf32_Sym       *dynsymtab;
 103         void    (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym);
 104
 105         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 106
 107         // Check magic header
 108
 109
 110         // Parse Program Header to get Dynamic Table
 111         phtab = Base + hdr->phoff;
 112         iSegmentCount = hdr->phentcount;
 113         for(i=0;i<iSegmentCount;i++)
 114         {
 115                 // Determine linked base address
 116                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 117                         iRealBase = phtab[i].VAddr;
 118
 119                 // Find Dynamic Section
 120                 if(phtab[i].Type == PT_DYNAMIC) {
 121                         if(dynamicTab) {
 122                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 123                                 continue;
 124                         }
 125                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 126                         j = i;  // Save Dynamic Table ID
 127                 }
 128         }
 129
 130         // Page Align real base
 131         iRealBase &= ~0xFFF;
 132         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 133
 134         // Adjust "Real" Base
 135         iBaseDiff = (intptr_t)Base - iRealBase;
 136
 137 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 138
 139         // Check if a PT_DYNAMIC segement was found
 140         if(!dynamicTab) {
 141                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 142                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 143         }
 144
 145         // Adjust Dynamic Table
 146         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 147
 148         // === Get Symbol table and String Table ===
 149         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 150         {
 151                 switch(dynamicTab[j].d_tag)
 152                 {
 153                 // --- Symbol Table ---
 154                 case DT_SYMTAB:
 155                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 156                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 157                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 158                         dynsymtab = (void*)(intptr_t)dynamicTab[j].d_val;
 159                         break;
 160                 // --- String Table ---
 161                 case DT_STRTAB:
 162                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 163                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 164                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 165                         dynstrtab = (void*)(intptr_t)dynamicTab[j].d_val;
 166                         break;
 167                 // --- Hash Table --
 168                 case DT_HASH:
 169                         if(iBaseDiff != 0)      dynamicTab[j].d_val += iBaseDiff;
 170                         iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
 171                         break;
 172                 }
 173         }
 174
 175         if(dynsymtab == NULL) {
 176                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 177                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 178         }
 179
 180         // === Add to loaded list (can be imported now) ===
 181         AddLoaded( Filename, Base );
 182
 183         // === Parse Relocation Data ===
 184         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 185         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 186         {
 187                 switch(dynamicTab[j].d_tag)
 188                 {
 189                 // --- Shared Library Name ---
 190                 case DT_SONAME:
 191                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 192                         break;
 193                 // --- Needed Library ---
 194                 case DT_NEEDED:
 195                         libPath = dynstrtab + dynamicTab[j].d_val;
 196                         DEBUGS(" Required Library '%s'", libPath);
 197                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 198                                 #if DEBUG
 199                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 200                                 #else
 201                                 SysDebug("Unable to load required library '%s'", libPath);
 202                                 #endif
 203                                 return 0;
 204                         }
 205                         DEBUGS(" Lib loaded");
 206                         break;
 207                 // --- PLT/GOT ---
 208                 case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 209                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 210                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 211                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 212
 213                 // --- Relocation ---
 214                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 215                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 216                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 217                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 218                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 219                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 220
 221                 // --- Symbol Table ---
 222                 case DT_SYMTAB:
 223                 // --- Hash Table ---
 224                 case DT_HASH:
 225                 // --- String Table ---
 226                 case DT_STRTAB:
 227                         break;
 228
 229                 // --- Unknown ---
 230                 default:
 231                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 232                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 233                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 234                         break;
 235                 }
 236         }
 237
 238         DEBUGS(" elf_relocate: Beginning Relocation");
 239
 240         void elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
 241         {
 242                 Uint32  val;
 243                 switch( type )
 244                 {
 245                 // Standard 32 Bit Relocation (S+A)
 246                 case R_386_32:
 247                         val = (intptr_t) GetSymbol(Sym, NULL);
 248                         DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')",
 249                                         ptr, val, Sym);
 250                         *ptr = val + addend;
 251                         break;
 252
 253                 // 32 Bit Relocation wrt. Offset (S+A-P)
 254                 case R_386_PC32:
 255                         DEBUGS(" elf_doRelocate: '%s'", Sym);
 256                         val = (intptr_t) GetSymbol(Sym, NULL);
 257                         DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x",
 258                                 ptr, *ptr, val, (intptr_t)ptr );
 259                         *ptr = val + addend - (intptr_t)ptr;
 260                         //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 261                         break;
 262
 263                 // Absolute Value of a symbol (S)
 264                 case R_386_GLOB_DAT:
 265                 case R_386_JMP_SLOT:
 266                         DEBUGS(" elf_doRelocate: '%s'", Sym);
 267                         val = (intptr_t) GetSymbol( Sym, NULL );
 268                         DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x", csaR_NAMES[type], ptr, val);
 269                         *ptr = val;
 270                         break;
 271
 272                 // Base Address (B+A)
 273                 case R_386_RELATIVE:
 274                         DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 275                         *ptr = iBaseDiff + addend;
 276                         break;
 277
 278                 case R_386_COPY: {
 279                         size_t  size;
 280                         void    *src = GetSymbol(Sym, &size);
 281                         DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, src, size);
 282                         memcpy(ptr, src, size);
 283                         break; }
 284
 285                 default:
 286                         SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 287                         break;
 288                 }
 289         }
 290
 291         void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym)
 292         {
 293                 uint32_t        val;
 294                 switch(type)
 295                 {
 296                 // (S + A) | T
 297                 case R_ARM_GLOB_DAT:
 298                         DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
 299                         val = (intptr_t)GetSymbol(Sym, NULL);
 300                         *ptr = val + addend;
 301                         break;
 302                 case R_ARM_JUMP_SLOT:
 303                         if(!bRela)      addend = 0;
 304                         DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
 305                         val = (intptr_t)GetSymbol(Sym, NULL);
 306                         *ptr = val + addend;
 307                         break;
 308                 default:
 309                         SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 310                         break;
 311                 }
 312         }
 313
 314         void _doRelocate(uint32_t r_info, uint32_t *ptr, int bRela, Elf32_Addr addend)
 315         {
 316                  int    type = ELF32_R_TYPE(r_info);
 317                  int    sym = ELF32_R_SYM(r_info);
 318                 const char      *symname = dynstrtab + dynsymtab[sym].nameOfs;
 319                 do_relocate(r_info, ptr, addend, type, bRela, symname);
 320         }
 321
 322         switch(hdr->machine)
 323         {
 324         case EM_386:
 325                 do_relocate = elf_doRelocate_386;
 326                 break;
 327         case EM_ARM:
 328                 do_relocate = elf_doRelocate_arm;
 329                 break;
 330         default:
 331                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 332                 break;
 333         }
 334
 335         // Parse Relocation Entries
 336         if(rel && relSz)
 337         {
 338                 Uint32  *ptr;
 339                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 340                 j = relSz / relEntSz;
 341                 for( i = 0; i < j; i++ )
 342                 {
 343                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 344                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 345                         _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 346                 }
 347         }
 348         // Parse Relocation Entries
 349         if(rela && relaSz)
 350         {
 351                 Uint32  *ptr;
 352                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 353                 j = relaSz / relaEntSz;
 354                 for( i = 0; i < j; i++ )
 355                 {
 356                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 357                         _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 358                 }
 359         }
 360
 361         // === Process PLT (Procedure Linkage Table) ===
 362         if(plt && pltSz)
 363         {
 364                 Uint32  *ptr;
 365                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 366                 if(pltType == DT_REL)
 367                 {
 368                         Elf32_Rel       *pltRel = plt;
 369                         j = pltSz / sizeof(Elf32_Rel);
 370                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 371                         for(i=0;i<j;i++)
 372                         {
 373                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 374                                 _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 375                         }
 376                 }
 377                 else
 378                 {
 379                         Elf32_Rela      *pltRela = plt;
 380                         j = pltSz / sizeof(Elf32_Rela);
 381                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 382                         for(i=0;i<j;i++)
 383                         {
 384                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 385                                 _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 386                         }
 387                 }
 388         }
 389
 390         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 391         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 392 }
 393
 394 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 395 {
 396         Elf32_Ehdr      *hdr = Base;
 397         Elf32_Sym       *symtab;
 398          int    nbuckets = 0;
 399          int    iSymCount = 0;
 400          int    i;
 401         Uint32  *pBuckets;
 402         Uint32  *pChains;
 403         uint32_t        iNameHash;
 404         const char      *dynstrtab;
 405         uintptr_t       iBaseDiff = -1;
 406         Elf32_Phdr      *phtab;
 407         Elf32_Dyn       *dynTab = NULL;
 408
 409         // Locate the tables
 410         phtab = (void*)( Base + hdr->phoff );
 411         for( i = 0; i < hdr->phentcount; i ++ )
 412         {
 413                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 414                         iBaseDiff = phtab[i].VAddr;
 415                 if( phtab[i].Type == PT_DYNAMIC ) {
 416                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 417                 }
 418         }
 419         if( !dynTab ) {
 420                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 421                 return 0;
 422         }
 423         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 424         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 425         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 426         {
 427                 switch(dynTab[i].d_tag)
 428                 {
 429                 // --- Symbol Table ---
 430                 case DT_SYMTAB:
 431                         symtab = (void*)(intptr_t) dynTab[i].d_val;     // Rebased in Relocate
 432                         break;
 433                 case DT_STRTAB:
 434                         dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
 435                         break;
 436                 // --- Hash Table --
 437                 case DT_HASH:
 438                         pBuckets = (void*)(intptr_t) dynTab[i].d_val;
 439                         break;
 440                 }
 441         }
 442
 443         nbuckets = pBuckets[0];
 444         iSymCount = pBuckets[1];
 445         pBuckets = &pBuckets[2];
 446         pChains = &pBuckets[ nbuckets ];
 447
 448         // Get hash
 449         iNameHash = ElfHashString(Name);
 450         iNameHash %= nbuckets;
 451
 452         // Walk Chain
 453         i = pBuckets[ iNameHash ];
 454         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 455                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 456                 if(Size)        *Size = symtab[i].size;
 457                 return 1;
 458         }
 459
 460         while(pChains[i] != STN_UNDEF)
 461         {
 462                 i = pChains[i];
 463                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 464                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 465                         if(Size)        *Size = symtab[i].size;
 466                         return 1;
 467                 }
 468         }
 469
 470         return 0;
 471 }
 472
 473 #ifdef SUPPORT_ELF64
 474 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 475 {
 476          int    i;
 477         Elf64_Ehdr      *hdr = Base;
 478         Elf64_Phdr      *phtab;
 479         Elf64_Dyn       *dyntab;
 480         Elf64_Addr      compiledBase = -1, baseDiff;
 481         Elf64_Sym       *symtab = NULL;
 482         char    *strtab = NULL;
 483         Elf64_Word      *hashtab = NULL;
 484         Elf64_Rel       *rel = NULL;
 485          int    rel_count = 0;
 486         Elf64_Rela      *rela = NULL;
 487          int    rela_count = 0;
 488         void    *pltrel = NULL;
 489          int    plt_size = 0, plt_type = 0;
 490
 491         DEBUGS("Elf64Relocate: hdr = {");
 492         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 493         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 494         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 495         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 496         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 497         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 498         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 499         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 500         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 501         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 502         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 503
 504         // Scan for the dynamic table (and find the compiled base)
 505         phtab = Base + hdr->e_phoff;
 506         for( i = 0; i < hdr->e_phnum; i ++ )
 507         {
 508                 if(phtab[i].p_type == PT_DYNAMIC)
 509                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 510                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 511                         compiledBase = phtab[i].p_vaddr;
 512         }
 513
 514         baseDiff = (Elf64_Addr)Base - compiledBase;
 515
 516         DEBUGS("baseDiff = %p", baseDiff);
 517
 518         if(dyntab == NULL) {
 519                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 520                 return (void *)(hdr->e_entry + baseDiff);
 521         }
 522
 523         dyntab = (void *)((Elf64_Addr)dyntab + baseDiff);
 524
 525         // Parse the dynamic table (first pass)
 526         // - Search for String, Symbol and Hash tables
 527         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 528         {
 529                 switch(dyntab[i].d_tag)
 530                 {
 531                 case DT_SYMTAB:
 532                         dyntab[i].d_un.d_ptr += baseDiff;
 533                         symtab = (void *)dyntab[i].d_un.d_ptr;
 534                         break;
 535                 case DT_STRTAB:
 536                         dyntab[i].d_un.d_ptr += baseDiff;
 537                         strtab = (void *)dyntab[i].d_un.d_ptr;
 538                         break;
 539                 case DT_HASH:
 540                         dyntab[i].d_un.d_ptr += baseDiff;
 541                         hashtab = (void *)dyntab[i].d_un.d_ptr;
 542                         break;
 543                 }
 544         }
 545
 546         if( !symtab || !strtab || !hashtab ) {
 547                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 548                 return NULL;
 549         }
 550
 551         // Ready for symbol use
 552         AddLoaded( Filename, Base );
 553
 554         // Second pass on dynamic table
 555         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 556         {
 557                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 558                 switch(dyntab[i].d_tag)
 559                 {
 560                 case DT_SONAME: break;
 561
 562                 case DT_NEEDED: {
 563                         char *libPath = strtab + dyntab[i].d_un.d_val;
 564                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 565                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 566                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 567                                 return NULL;
 568                         }
 569                         } break;
 570
 571                 // Relocation entries
 572                 case DT_REL:
 573                         dyntab[i].d_un.d_ptr += baseDiff;
 574                         rel = (void *)dyntab[i].d_un.d_ptr;
 575                         break;
 576                 case DT_RELSZ:
 577                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 578                         break;
 579                 case DT_RELENT:
 580                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 581                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 582                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 583                                 return NULL;
 584                         }
 585                         break;
 586                 case DT_RELA:
 587                         dyntab[i].d_un.d_ptr += baseDiff;
 588                         rela = (void *)dyntab[i].d_un.d_ptr;
 589                         break;
 590                 case DT_RELASZ:
 591                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 592                         break;
 593                 case DT_RELAENT:
 594                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 595                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 596                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 597                                 return NULL;
 598                         }
 599                         break;
 600                 case DT_JMPREL:
 601                         dyntab[i].d_un.d_ptr += baseDiff;
 602                         pltrel = (void *)dyntab[i].d_un.d_ptr;
 603                         break;
 604                 case DT_PLTREL:
 605                         plt_type = dyntab[i].d_un.d_val;
 606                         break;
 607                 case DT_PLTRELSZ:
 608                         plt_size = dyntab[i].d_un.d_val;
 609                         break;
 610                 }
 611         }
 612
 613         // Relocation function
 614         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 615         {
 616                  int    sym = ELF64_R_SYM(r_info);
 617                  int    type = ELF64_R_TYPE(r_info);
 618                 const char      *symname = strtab + symtab[sym].st_name;
 619                 switch( type )
 620                 {
 621                 case R_X86_64_NONE:
 622                         break;
 623                 case R_X86_64_64:
 624                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname, NULL) + addend;
 625                         break;
 626                 case R_X86_64_COPY: {
 627                         size_t  size;
 628                         void    *sym = GetSymbol(symname, &size);
 629                         memcpy(ptr, sym, size);
 630                         } break;
 631                 case R_X86_64_GLOB_DAT:
 632                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname, NULL);
 633                         break;
 634                 case R_X86_64_JUMP_SLOT:
 635                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname, NULL);
 636                         break;
 637                 case R_X86_64_RELATIVE:
 638                         *(uint64_t*)ptr = (intptr_t)Base + addend;
 639                         break;
 640                 default:
 641                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 642                         break;
 643                 }
 644         }
 645
 646         if( rel )
 647         {
 648                 DEBUGS("rel_count = %i", rel_count);
 649                 for( i = 0; i < rel_count; i ++ )
 650                 {
 651                         uint64_t *ptr = (void *)( rel[i].r_offset + baseDiff );
 652                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 653                 }
 654         }
 655
 656         if( rela )
 657         {
 658                 DEBUGS("rela_count = %i", rela_count);
 659                 for( i = 0; i < rela_count; i ++ )
 660                 {
 661                         _Elf64DoReloc( rela[i].r_info, (void *)( rela[i].r_offset + baseDiff ), rela[i].r_addend );
 662                 }
 663         }
 664
 665         if( pltrel && plt_type )
 666         {
 667                 if( plt_type == DT_REL ) {
 668                         Elf64_Rel       *plt = pltrel;
 669                          int    count = plt_size / sizeof(Elf64_Rel);
 670                         DEBUGS("plt rel count = %i", count);
 671                         for( i = 0; i < count; i ++ )
 672                         {
 673                                 uint64_t *ptr = (void *)( plt[i].r_offset + baseDiff );
 674                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 675                         }
 676                 }
 677                 else {
 678                         Elf64_Rela      *plt = pltrel;
 679                          int    count = plt_size / sizeof(Elf64_Rela);
 680                         DEBUGS("plt rela count = %i", count);
 681                         for( i = 0; i < count; i ++ )
 682                         {
 683                                 _Elf64DoReloc( plt[i].r_info, (void *)(plt[i].r_offset + baseDiff), plt[i].r_addend);
 684                         }
 685                 }
 686         }
 687
 688         DEBUGS("Elf64Relocate: Relocations done, return %p", (void *)(hdr->e_entry + baseDiff));
 689         return (void *)(hdr->e_entry + baseDiff);
 690 }
 691
 692 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 693 {
 694         Elf64_Ehdr      *hdr = Base;
 695         Elf64_Sym       *symtab;
 696          int    nbuckets = 0;
 697          int    iSymCount = 0;
 698          int    i;
 699         Elf64_Word      *pBuckets;
 700         Elf64_Word      *pChains;
 701         uint32_t        iNameHash;
 702         const char      *dynstrtab;
 703         uintptr_t       iBaseDiff = -1;
 704
 705         dynstrtab = NULL;
 706         pBuckets = NULL;
 707         symtab = NULL;
 708
 709         // Catch the current executable
 710         if( !pBuckets )
 711         {
 712                 Elf64_Phdr      *phtab;
 713                 Elf64_Dyn       *dynTab = NULL;
 714                  int    j;
 715
 716                 // Locate the tables
 717                 phtab = (void*)( Base + hdr->e_phoff );
 718                 for( i = 0; i < hdr->e_phnum; i ++ )
 719                 {
 720                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 721                                 iBaseDiff = phtab[i].p_vaddr;
 722                         if( phtab[i].p_type == PT_DYNAMIC ) {
 723                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 724                         }
 725                 }
 726                 if( !dynTab ) {
 727                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 728                         return 0;
 729                 }
 730                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 731                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 732
 733                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 734                 {
 735                         switch(dynTab[j].d_tag)
 736                         {
 737                         // --- Symbol Table ---
 738                         case DT_SYMTAB:
 739                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 740                                 break;
 741                         case DT_STRTAB:
 742                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 743                                 break;
 744                         // --- Hash Table --
 745                         case DT_HASH:
 746                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 747                                 break;
 748                         }
 749                 }
 750         }
 751
 752         nbuckets = pBuckets[0];
 753         iSymCount = pBuckets[1];
 754         pBuckets = &pBuckets[2];
 755         pChains = &pBuckets[ nbuckets ];
 756
 757         // Get hash
 758         iNameHash = ElfHashString(Name);
 759         iNameHash %= nbuckets;
 760
 761         // Walk Chain
 762         i = pBuckets[ iNameHash ];
 763         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 764                 *Ret = (void*) (intptr_t) symtab[i].st_value + iBaseDiff;
 765                 if(Size)        *Size = symtab[i].st_size;
 766                 DEBUGS("%s = %p", Name, *Ret);
 767                 return 1;
 768         }
 769
 770         while(pChains[i] != STN_UNDEF)
 771         {
 772                 i = pChains[i];
 773                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 774                         *Ret = (void*)(intptr_t)symtab[i].st_value + iBaseDiff;
 775                         if(Size)        *Size = symtab[i].st_size;
 776                         DEBUGS("%s = %p", Name, *Ret);
 777                         return 1;
 778                 }
 779         }
 780
 781         return 0;
 782 }
 783 #endif
 784
 785
 786 Uint32 ElfHashString(const char *name)
 787 {
 788         Uint32  h = 0, g;
 789         while(*name)
 790         {
 791                 h = (h << 4) + *(Uint8*)name++;
 792                 if( (g = h & 0xf0000000) )
 793                         h ^= g >> 24;
 794                 h &= ~g;
 795         }
 796         return h;
 797 }
 798