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

   1 /*
   2  * AcessOS 1 - Dynamic Loader
   3  * By thePowersGang
   4  */
   5 #include "common.h"
   6 #include <stdint.h>
   7 #include "elf32.h"
   8 #include "elf64.h"
   9
  10 #define DEBUG   1
  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);
  31 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  32  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret);
  33 #ifdef SUPPORT_ELF64
  34 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  35  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret);
  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)
  66 {
  67         Elf32_Ehdr      *hdr = Base;
  68
  69         switch(hdr->e_ident[4])
  70         {
  71         case ELFCLASS32:
  72                 return Elf32GetSymbol(Base, Name, ret);
  73 #ifdef SUPPORT_ELF64
  74         case ELFCLASS64:
  75                 return Elf64GetSymbol(Base, Name, ret);
  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, 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*)(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*)(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*)(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 *) 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, 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 );
 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 );
 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 );
 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                 default:
 279                         SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 280                         break;
 281                 }
 282         }
 283
 284         void elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, const char *Sym)
 285         {
 286                 uint32_t        val;
 287                 switch(type)
 288                 {
 289                 // (S + A) | T
 290                 case R_ARM_GLOB_DAT:
 291                 case R_ARM_JUMP_SLOT:
 292                         val = (intptr_t)GetSymbol(Sym);
 293                         *ptr = val + addend;
 294                         break;
 295                 default:
 296                         SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 297                         break;
 298                 }
 299         }
 300
 301         void _doRelocate(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend)
 302         {
 303                  int    type = ELF32_R_TYPE(r_info);
 304                  int    sym = ELF32_R_SYM(r_info);
 305                 const char      *symname = dynstrtab + dynsymtab[sym].nameOfs;
 306                 do_relocate(r_info, ptr, addend, type, symname);
 307         }
 308
 309         switch(hdr->machine)
 310         {
 311         case EM_386:
 312                 do_relocate = elf_doRelocate_386;
 313                 break;
 314         case EM_ARM:
 315                 do_relocate = elf_doRelocate_arm;
 316                 break;
 317         default:
 318                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 319                 break;
 320         }
 321
 322         // Parse Relocation Entries
 323         if(rel && relSz)
 324         {
 325                 Uint32  *ptr;
 326                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 327                 j = relSz / relEntSz;
 328                 for( i = 0; i < j; i++ )
 329                 {
 330                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 331                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 332                         _doRelocate(rel[i].r_info, ptr, *ptr);
 333                 }
 334         }
 335         // Parse Relocation Entries
 336         if(rela && relaSz)
 337         {
 338                 Uint32  *ptr;
 339                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 340                 j = relaSz / relaEntSz;
 341                 for( i = 0; i < j; i++ )
 342                 {
 343                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 344                         _doRelocate(rel[i].r_info, ptr, rela[i].r_addend);
 345                 }
 346         }
 347
 348         // === Process PLT (Procedure Linkage Table) ===
 349         if(plt && pltSz)
 350         {
 351                 Uint32  *ptr;
 352                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 353                 if(pltType == DT_REL)
 354                 {
 355                         Elf32_Rel       *pltRel = plt;
 356                         j = pltSz / sizeof(Elf32_Rel);
 357                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 358                         for(i=0;i<j;i++)
 359                         {
 360                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 361                                 _doRelocate(pltRel[i].r_info, ptr, *ptr);
 362                         }
 363                 }
 364                 else
 365                 {
 366                         Elf32_Rela      *pltRela = plt;
 367                         j = pltSz / sizeof(Elf32_Rela);
 368                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 369                         for(i=0;i<j;i++)
 370                         {
 371                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 372                                 _doRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend);
 373                         }
 374                 }
 375         }
 376
 377         DEBUGS("ElfRelocate: RETURN 0x%x", hdr->entrypoint + iBaseDiff);
 378         return (void*)hdr->entrypoint + iBaseDiff;
 379 }
 380
 381 int Elf32GetSymbol(void *Base, const char *Name, void **ret)
 382 {
 383         Elf32_Ehdr      *hdr = Base;
 384         Elf32_Sym       *symtab;
 385          int    nbuckets = 0;
 386          int    iSymCount = 0;
 387          int    i;
 388         Uint32  *pBuckets;
 389         Uint32  *pChains;
 390         uint32_t        iNameHash;
 391         const char      *dynstrtab;
 392         uintptr_t       iBaseDiff = -1;
 393         Elf32_Phdr      *phtab;
 394         Elf32_Dyn       *dynTab = NULL;
 395
 396         // Locate the tables
 397         phtab = (void*)( Base + hdr->phoff );
 398         for( i = 0; i < hdr->phentcount; i ++ )
 399         {
 400                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 401                         iBaseDiff = phtab[i].VAddr;
 402                 if( phtab[i].Type == PT_DYNAMIC ) {
 403                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 404                 }
 405         }
 406         if( !dynTab ) {
 407                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 408                 return 0;
 409         }
 410         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 411         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 412         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 413         {
 414                 switch(dynTab[i].d_tag)
 415                 {
 416                 // --- Symbol Table ---
 417                 case DT_SYMTAB:
 418                         symtab = (void*)(intptr_t) dynTab[i].d_val;     // Rebased in Relocate
 419                         break;
 420                 case DT_STRTAB:
 421                         dynstrtab = (void*)(intptr_t) dynTab[i].d_val;
 422                         break;
 423                 // --- Hash Table --
 424                 case DT_HASH:
 425                         pBuckets = (void*)(intptr_t) dynTab[i].d_val;
 426                         break;
 427                 }
 428         }
 429
 430         nbuckets = pBuckets[0];
 431         iSymCount = pBuckets[1];
 432         pBuckets = &pBuckets[2];
 433         pChains = &pBuckets[ nbuckets ];
 434
 435         // Get hash
 436         iNameHash = ElfHashString(Name);
 437         iNameHash %= nbuckets;
 438
 439         // Walk Chain
 440         i = pBuckets[ iNameHash ];
 441         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 442                 *ret = (void*) (intptr_t) symtab[ i ].value + iBaseDiff;
 443                 return 1;
 444         }
 445
 446         while(pChains[i] != STN_UNDEF)
 447         {
 448                 i = pChains[i];
 449                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 450                         *ret = (void*)(intptr_t)symtab[ i ].value + iBaseDiff;
 451                         return 1;
 452                 }
 453         }
 454
 455         return 0;
 456 }
 457
 458 #ifdef SUPPORT_ELF64
 459 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 460 {
 461          int    i;
 462         Elf64_Ehdr      *hdr = Base;
 463         Elf64_Phdr      *phtab;
 464         Elf64_Dyn       *dyntab;
 465         Elf64_Addr      compiledBase = -1, baseDiff;
 466         Elf64_Sym       *symtab = NULL;
 467         char    *strtab = NULL;
 468         Elf64_Word      *hashtab = NULL;
 469         Elf64_Rel       *rel = NULL;
 470          int    rel_count = 0;
 471         Elf64_Rela      *rela = NULL;
 472          int    rela_count = 0;
 473         void    *pltrel = NULL;
 474          int    plt_size = 0, plt_type = 0;
 475
 476         DEBUGS("Elf64Relocate: hdr = {");
 477         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 478         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 479         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 480         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 481         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 482         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 483         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 484         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 485         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 486         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 487         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 488
 489         // Scan for the dynamic table (and find the compiled base)
 490         phtab = Base + hdr->e_phoff;
 491         for( i = 0; i < hdr->e_phnum; i ++ )
 492         {
 493                 if(phtab[i].p_type == PT_DYNAMIC)
 494                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 495                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 496                         compiledBase = phtab[i].p_vaddr;
 497         }
 498
 499         baseDiff = (Elf64_Addr)Base - compiledBase;
 500
 501         DEBUGS("baseDiff = %p", baseDiff);
 502
 503         if(dyntab == NULL) {
 504                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 505                 return (void *)(hdr->e_entry + baseDiff);
 506         }
 507
 508         dyntab = (void *)((Elf64_Addr)dyntab + baseDiff);
 509
 510         // Parse the dynamic table (first pass)
 511         // - Search for String, Symbol and Hash tables
 512         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 513         {
 514                 switch(dyntab[i].d_tag)
 515                 {
 516                 case DT_SYMTAB:
 517                         dyntab[i].d_un.d_ptr += baseDiff;
 518                         symtab = (void *)dyntab[i].d_un.d_ptr;
 519                         break;
 520                 case DT_STRTAB:
 521                         dyntab[i].d_un.d_ptr += baseDiff;
 522                         strtab = (void *)dyntab[i].d_un.d_ptr;
 523                         break;
 524                 case DT_HASH:
 525                         dyntab[i].d_un.d_ptr += baseDiff;
 526                         hashtab = (void *)dyntab[i].d_un.d_ptr;
 527                         break;
 528                 }
 529         }
 530
 531         if( !symtab || !strtab || !hashtab ) {
 532                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 533                 return NULL;
 534         }
 535
 536         // Ready for symbol use
 537         AddLoaded( Filename, Base );
 538
 539         // Second pass on dynamic table
 540         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 541         {
 542                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 543                 switch(dyntab[i].d_tag)
 544                 {
 545                 case DT_SONAME: break;
 546
 547                 case DT_NEEDED: {
 548                         char *libPath = strtab + dyntab[i].d_un.d_val;
 549                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 550                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 551                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 552                                 return NULL;
 553                         }
 554                         } break;
 555
 556                 // Relocation entries
 557                 case DT_REL:
 558                         dyntab[i].d_un.d_ptr += baseDiff;
 559                         rel = (void *)dyntab[i].d_un.d_ptr;
 560                         break;
 561                 case DT_RELSZ:
 562                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 563                         break;
 564                 case DT_RELENT:
 565                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 566                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 567                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 568                                 return NULL;
 569                         }
 570                         break;
 571                 case DT_RELA:
 572                         dyntab[i].d_un.d_ptr += baseDiff;
 573                         rela = (void *)dyntab[i].d_un.d_ptr;
 574                         break;
 575                 case DT_RELASZ:
 576                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 577                         break;
 578                 case DT_RELAENT:
 579                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 580                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 581                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 582                                 return NULL;
 583                         }
 584                         break;
 585                 case DT_JMPREL:
 586                         dyntab[i].d_un.d_ptr += baseDiff;
 587                         pltrel = (void *)dyntab[i].d_un.d_ptr;
 588                         break;
 589                 case DT_PLTREL:
 590                         plt_type = dyntab[i].d_un.d_val;
 591                         break;
 592                 case DT_PLTRELSZ:
 593                         plt_size = dyntab[i].d_un.d_val;
 594                         break;
 595                 }
 596         }
 597
 598         // Relocation function
 599         void _Elf64DoReloc(Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 600         {
 601                  int    sym = ELF64_R_SYM(r_info);
 602                  int    type = ELF64_R_TYPE(r_info);
 603                 const char      *symname = strtab + symtab[sym].st_name;
 604                 switch( type )
 605                 {
 606                 case R_X86_64_NONE:
 607                         break;
 608                 case R_X86_64_64:
 609                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname) + addend;
 610                         break;
 611                 case R_X86_64_COPY:
 612                         break;
 613                 case R_X86_64_GLOB_DAT:
 614                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname);
 615                         break;
 616                 case R_X86_64_JUMP_SLOT:
 617                         *(uint64_t*)ptr = (uint64_t)GetSymbol(symname);
 618                         break;
 619                 default:
 620                         SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 621                         break;
 622                 }
 623         }
 624
 625         if( rel )
 626         {
 627                 DEBUGS("rel_count = %i", rel_count);
 628                 for( i = 0; i < rel_count; i ++ )
 629                 {
 630                         uint64_t *ptr = (void *)( rel[i].r_offset + baseDiff );
 631                         _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 632                 }
 633         }
 634
 635         if( rela )
 636         {
 637                 DEBUGS("rela_count = %i", rela_count);
 638                 for( i = 0; i < rela_count; i ++ )
 639                 {
 640                         _Elf64DoReloc( rela[i].r_info, (void *)( rela[i].r_offset + baseDiff ), rela[i].r_addend );
 641                 }
 642         }
 643
 644         if( pltrel && plt_type )
 645         {
 646                 if( plt_type == DT_REL ) {
 647                         Elf64_Rel       *plt = pltrel;
 648                          int    count = plt_size / sizeof(Elf64_Rel);
 649                         DEBUGS("plt rel count = %i", count);
 650                         for( i = 0; i < count; i ++ )
 651                         {
 652                                 uint64_t *ptr = (void *)( plt[i].r_offset + baseDiff );
 653                                 _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 654                         }
 655                 }
 656                 else {
 657                         Elf64_Rela      *plt = pltrel;
 658                          int    count = plt_size / sizeof(Elf64_Rela);
 659                         DEBUGS("plt rela count = %i", count);
 660                         for( i = 0; i < count; i ++ )
 661                         {
 662                                 _Elf64DoReloc( plt[i].r_info, (void *)(plt[i].r_offset + baseDiff), plt[i].r_addend);
 663                         }
 664                 }
 665         }
 666
 667         DEBUGS("Elf64Relocate: Relocations done, return %p", (void *)(hdr->e_entry + baseDiff));
 668         return (void *)(hdr->e_entry + baseDiff);
 669 }
 670
 671 int Elf64GetSymbol(void *Base, const char *Name, void **Ret)
 672 {
 673         Elf64_Ehdr      *hdr = Base;
 674         Elf64_Sym       *symtab;
 675          int    nbuckets = 0;
 676          int    iSymCount = 0;
 677          int    i;
 678         Elf64_Word      *pBuckets;
 679         Elf64_Word      *pChains;
 680         uint32_t        iNameHash;
 681         const char      *dynstrtab;
 682         uintptr_t       iBaseDiff = -1;
 683
 684         dynstrtab = NULL;
 685         pBuckets = NULL;
 686         symtab = NULL;
 687
 688         // Catch the current executable
 689         if( !pBuckets )
 690         {
 691                 Elf64_Phdr      *phtab;
 692                 Elf64_Dyn       *dynTab = NULL;
 693                  int    j;
 694
 695                 // Locate the tables
 696                 phtab = (void*)( Base + hdr->e_phoff );
 697                 for( i = 0; i < hdr->e_phnum; i ++ )
 698                 {
 699                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 700                                 iBaseDiff = phtab[i].p_vaddr;
 701                         if( phtab[i].p_type == PT_DYNAMIC ) {
 702                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 703                         }
 704                 }
 705                 if( !dynTab ) {
 706                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 707                         return 0;
 708                 }
 709                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 710                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 711
 712                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 713                 {
 714                         switch(dynTab[j].d_tag)
 715                         {
 716                         // --- Symbol Table ---
 717                         case DT_SYMTAB:
 718                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 719                                 break;
 720                         case DT_STRTAB:
 721                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 722                                 break;
 723                         // --- Hash Table --
 724                         case DT_HASH:
 725                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 726                                 break;
 727                         }
 728                 }
 729         }
 730
 731         nbuckets = pBuckets[0];
 732         iSymCount = pBuckets[1];
 733         pBuckets = &pBuckets[2];
 734         pChains = &pBuckets[ nbuckets ];
 735
 736         // Get hash
 737         iNameHash = ElfHashString(Name);
 738         iNameHash %= nbuckets;
 739
 740         // Walk Chain
 741         i = pBuckets[ iNameHash ];
 742         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 743                 *Ret = (void*) (intptr_t) symtab[i].st_value + iBaseDiff;
 744                 DEBUGS("%s = %p", Name, *Ret);
 745                 return 1;
 746         }
 747
 748         while(pChains[i] != STN_UNDEF)
 749         {
 750                 i = pChains[i];
 751                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 752                         *Ret = (void*)(intptr_t)symtab[i].st_value + iBaseDiff;
 753                         DEBUGS("%s = %p", Name, *Ret);
 754                         return 1;
 755                 }
 756         }
 757
 758         return 0;
 759 }
 760 #endif
 761
 762
 763 Uint32 ElfHashString(const char *name)
 764 {
 765         Uint32  h = 0, g;
 766         while(*name)
 767         {
 768                 h = (h << 4) + *(Uint8*)name++;
 769                 if( (g = h & 0xf0000000) )
 770                         h ^= g >> 24;
 771                 h &= ~g;
 772         }
 773         return h;
 774 }
 775