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

   1 /*
   2  * Acess2 Dynamic Linker
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * elf.c
   6  * - ELF32/ELF64 relocation
   7  */
   8 #ifndef DEBUG   // This code is #include'd from the kernel, so DEBUG may already be defined
   9 # define DEBUG  0
  10 #endif
  11
  12 #ifndef PAGE_SIZE
  13 # define PAGE_SIZE      4096
  14 #endif
  15
  16 #include "common.h"
  17 #include <stdint.h>
  18 #include "elf32.h"
  19 #include "elf64.h"
  20
  21 #if DEBUG
  22 # define        DEBUGS(v...)    SysDebug("ld-acess - " v)
  23 #else
  24 # define        DEBUGS(...)
  25 #endif
  26
  27 #ifndef DISABLE_ELF64
  28 # define SUPPORT_ELF64
  29 #endif
  30
  31 // === CONSTANTS ===
  32 #if DEBUG
  33 //static const char     *csaDT_NAMES[] = {"DT_NULL", "DT_NEEDED", "DT_PLTRELSZ", "DT_PLTGOT", "DT_HASH", "DT_STRTAB", "DT_SYMTAB", "DT_RELA", "DT_RELASZ", "DT_RELAENT", "DT_STRSZ", "DT_SYMENT", "DT_INIT", "DT_FINI", "DT_SONAME", "DT_RPATH", "DT_SYMBOLIC", "DT_REL", "DT_RELSZ", "DT_RELENT", "DT_PLTREL", "DT_DEBUG", "DT_TEXTREL", "DT_JMPREL"};
  34 static const char       *csaR_NAMES[] = {"R_386_NONE", "R_386_32", "R_386_PC32", "R_386_GOT32", "R_386_PLT32", "R_386_COPY", "R_386_GLOB_DAT", "R_386_JMP_SLOT", "R_386_RELATIVE", "R_386_GOTOFF", "R_386_GOTPC", "R_386_LAST"};
  35 #endif
  36
  37 // === PROTOTYPES ===
  38 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  39  int    ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  40 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  41  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  42  int    elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  43  int    elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff);
  44  int    elf_doRelocate_unk(uint32_t , uint32_t *, Elf32_Addr , int , int , const char *, intptr_t);
  45 #ifdef SUPPORT_ELF64
  46 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  47  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  48 #endif
  49 uint32_t        ElfHashString(const char *name);
  50
  51 // === CODE ===
  52 /**
  53  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  54  * \brief Relocates a loaded ELF Executable
  55  */
  56 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  57 {
  58         Elf32_Ehdr      *hdr = Base;
  59
  60         switch(hdr->e_ident[4])
  61         {
  62         case ELFCLASS32:
  63                 return Elf32Relocate(Base, envp, Filename);
  64 #ifdef SUPPORT_ELF64
  65         case ELFCLASS64:
  66                 return Elf64Relocate(Base, envp, Filename);
  67 #endif
  68         default:
  69                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  70                 return NULL;
  71         }
  72 }
  73
  74 /**
  75  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  76  */
  77 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  78 {
  79         Elf32_Ehdr      *hdr = Base;
  80
  81         switch(hdr->e_ident[4])
  82         {
  83         case ELFCLASS32:
  84                 return Elf32GetSymbol(Base, Name, ret, Size);
  85 #ifdef SUPPORT_ELF64
  86         case ELFCLASS64:
  87                 return Elf64GetSymbol(Base, Name, ret, Size);
  88 #endif
  89         default:
  90                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  91                 return 0;
  92         }
  93 }
  94
  95 int elf_doRelocate_386(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type,
  96                 int bRela, const char *Sym, intptr_t iBaseDiff)
  97 {
  98         void    *symval;
  99         switch( type )
 100         {
 101         // Standard 32 Bit Relocation (S+A)
 102         case R_386_32:
 103                 if( !GetSymbol(Sym, &symval, NULL) )
 104                         return 1;
 105                 DEBUGS(" elf_doRelocate: R_386_32 *0x%x += %p('%s')",
 106                                 ptr, symval, Sym);
 107                 *ptr = (intptr_t)symval + addend;
 108                 break;
 109
 110         // 32 Bit Relocation wrt. Offset (S+A-P)
 111         case R_386_PC32:
 112                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 113                 if( !GetSymbol(Sym, &symval, NULL) )    return 1;
 114                 DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%p - 0x%x",
 115                         ptr, *ptr, symval, (intptr_t)ptr );
 116                 *ptr = (intptr_t)symval + addend - (intptr_t)ptr;
 117                 //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 118                 break;
 119
 120         // Absolute Value of a symbol (S)
 121         case R_386_GLOB_DAT:
 122         case R_386_JMP_SLOT:
 123                 DEBUGS(" elf_doRelocate: '%s'", Sym);
 124                 if( !GetSymbol(Sym, &symval, NULL) )    return 1;
 125                 DEBUGS(" elf_doRelocate: %s *0x%x = %p", csaR_NAMES[type], ptr, symval);
 126                 *ptr = (intptr_t)symval;
 127                 break;
 128
 129         // Base Address (B+A)
 130         case R_386_RELATIVE:
 131                 DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, iBaseDiff, addend);
 132                 *ptr = iBaseDiff + addend;
 133                 break;
 134
 135         case R_386_COPY: {
 136                 size_t  size;
 137                 if( !GetSymbol(Sym, &symval, &size) )   return 1;
 138                 DEBUGS(" elf_doRelocate_386: R_386_COPY (%p, %p, %i)", ptr, symval, size);
 139                 memcpy(ptr, symval, size);
 140                 break; }
 141
 142         default:
 143                 SysDebug("elf_doRelocate_386: Unknown relocation %i", type);
 144                 return 2;
 145         }
 146         return 0;
 147 }
 148
 149 int elf_doRelocate_arm(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
 150 {
 151         uint32_t        val;
 152         switch(type)
 153         {
 154         // (S + A) | T
 155         case R_ARM_ABS32:
 156                 DEBUGS(" elf_doRelocate_arm: R_ARM_ABS32 %p (%s + %x)", ptr, Sym, addend);
 157                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 158                 *ptr = val + addend;
 159                 break;
 160         case R_ARM_GLOB_DAT:
 161                 DEBUGS(" elf_doRelocate_arm: R_ARM_GLOB_DAT %p (%s + %x)", ptr, Sym, addend);
 162                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 163                 *ptr = val + addend;
 164                 break;
 165         case R_ARM_JUMP_SLOT:
 166                 if(!bRela)      addend = 0;
 167                 DEBUGS(" elf_doRelocate_arm: R_ARM_JUMP_SLOT %p (%s + %x)", ptr, Sym, addend);
 168                 if( !GetSymbol(Sym, (void**)&val, NULL) )       return 1;
 169                 *ptr = val + addend;
 170                 break;
 171         // Copy
 172         case R_ARM_COPY: {
 173                 size_t  size;
 174                 void    *src;
 175                 if( !GetSymbol(Sym, &src, &size) )      return 1;
 176                 DEBUGS(" elf_doRelocate_arm: R_ARM_COPY (%p, %p, %i)", ptr, src, size);
 177                 memcpy(ptr, src, size);
 178                 break; }
 179         // Delta between link and runtime locations + A
 180         case R_ARM_RELATIVE:
 181                 DEBUGS(" elf_doRelocate_arm: R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, iBaseDiff, addend);
 182                 if(Sym[0] != '\0') {
 183                         // TODO: Get delta for a symbol
 184                         SysDebug("elf_doRelocate_arm: TODO - Implment R_ARM_RELATIVE for symbols");
 185                         return 2;
 186                 }
 187                 else {
 188                         *ptr = iBaseDiff + addend;
 189                 }
 190                 break;
 191         default:
 192                 SysDebug("elf_doRelocate_arm: Unknown Relocation, %i", type);
 193                 return 2;
 194         }
 195         return 0;
 196 }
 197
 198 int elf_doRelocate_unk(uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int type, int bRela, const char *Sym, intptr_t iBaseDiff)
 199 {
 200         return 1;
 201 }
 202
 203 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 204 {
 205         Elf32_Ehdr      *hdr = Base;
 206         Elf32_Phdr      *phtab;
 207          int    i, j;   // Counters
 208         char    *libPath;
 209         intptr_t        iRealBase = -1;
 210         intptr_t        iBaseDiff;
 211          int    iSegmentCount;
 212 //       int    iSymCount;
 213         Elf32_Rel       *rel = NULL;
 214         Elf32_Rela      *rela = NULL;
 215         void    *plt = NULL;
 216          int    relSz=0, relEntSz=8;
 217          int    relaSz=0, relaEntSz=8;
 218          int    pltSz=0, pltType=0;
 219         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 220         char    *dynstrtab = NULL;      // .dynamic String Table
 221         Elf32_Sym       *dynsymtab;
 222         int     (*do_relocate)(uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int Type, int bRela, const char *Sym, intptr_t iBaseDiff);
 223
 224         DEBUGS("ElfRelocate: (Base=0x%x)", Base);
 225
 226         // Check magic header
 227
 228
 229         // Parse Program Header to get Dynamic Table
 230         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 231         iSegmentCount = hdr->phentcount;
 232         for(i=0;i<iSegmentCount;i++)
 233         {
 234                 // Determine linked base address
 235                 if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)
 236                         iRealBase = phtab[i].VAddr;
 237
 238                 // Find Dynamic Section
 239                 if(phtab[i].Type == PT_DYNAMIC) {
 240                         if(dynamicTab) {
 241                                 DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments");
 242                                 continue;
 243                         }
 244                         dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 245                         j = i;  // Save Dynamic Table ID
 246                 }
 247         }
 248
 249         // Page Align real base
 250         iRealBase &= ~0xFFF;
 251         DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 252
 253         // Adjust "Real" Base
 254         iBaseDiff = (intptr_t)Base - iRealBase;
 255
 256 //      hdr->entrypoint += iBaseDiff;   // Adjust Entrypoint
 257
 258         // Check if a PT_DYNAMIC segement was found
 259         if(!dynamicTab) {
 260                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 261                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 262         }
 263
 264         // Allow writing to read-only segments, just in case they need to be relocated
 265         // - Will be reversed at the end of the function
 266         for( i = 0; i < iSegmentCount; i ++ )
 267         {
 268                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 269                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 270                         uintptr_t       end = addr + phtab[i].MemSize;
 271                         for( ; addr < end; addr += PAGE_SIZE )
 272                                 _SysSetMemFlags(addr, 0, 1);    // Unset RO
 273                 }
 274         }
 275
 276         // Adjust Dynamic Table
 277         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 278
 279         // === Get Symbol table and String Table ===
 280         dynsymtab = NULL;
 281         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 282         {
 283                 switch(dynamicTab[j].d_tag)
 284                 {
 285                 // --- Symbol Table ---
 286                 case DT_SYMTAB:
 287                         DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)",
 288                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 289                         dynsymtab = (void*)((intptr_t)dynamicTab[j].d_val + iBaseDiff);
 290                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 291                         break;
 292                 // --- String Table ---
 293                 case DT_STRTAB:
 294                         DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)",
 295                                 dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);
 296                         dynstrtab = (void*)((intptr_t)dynamicTab[j].d_val + iBaseDiff);
 297                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 298                         break;
 299                 // --- Hash Table --
 300                 case DT_HASH:
 301                         //if(iBaseDiff != 0)    dynamicTab[j].d_val += iBaseDiff;
 302 //                      iSymCount = ((Elf32_Word*)(intptr_t)dynamicTab[j].d_val)[1];
 303                         break;
 304                 }
 305         }
 306
 307         if(dynsymtab == NULL) {
 308                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 309                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 310         }
 311
 312         // === Add to loaded list (can be imported now) ===
 313         AddLoaded( Filename, Base );
 314
 315         // === Parse Relocation Data ===
 316         DEBUGS(" elf_relocate: dynamicTab = 0x%x", dynamicTab);
 317         for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 318         {
 319                 switch(dynamicTab[j].d_tag)
 320                 {
 321                 // --- Shared Library Name ---
 322                 case DT_SONAME:
 323                         DEBUGS(" elf_relocate: .so Name '%s'", dynstrtab+dynamicTab[j].d_val);
 324                         break;
 325                 // --- Needed Library ---
 326                 case DT_NEEDED:
 327                         libPath = dynstrtab + dynamicTab[j].d_val;
 328                         DEBUGS(" dynstrtab = %p, d_val = 0x%x", dynstrtab, dynamicTab[j].d_val);
 329                         DEBUGS(" Required Library '%s'", libPath);
 330                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 331                                 #if DEBUG
 332                                 DEBUGS(" elf_relocate: Unable to load '%s'", libPath);
 333                                 #else
 334                                 SysDebug("Unable to load required library '%s'", libPath);
 335                                 #endif
 336                                 return 0;
 337                         }
 338                         DEBUGS(" Lib loaded");
 339                         break;
 340                 // --- PLT/GOT ---
 341 //              case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dynamicTab[j].d_val);      break;
 342                 case DT_JMPREL: plt = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 343                 case DT_PLTREL: pltType = dynamicTab[j].d_val;  break;
 344                 case DT_PLTRELSZ:       pltSz = dynamicTab[j].d_val;    break;
 345
 346                 // --- Relocation ---
 347                 case DT_REL:    rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;
 348                 case DT_RELSZ:  relSz = dynamicTab[j].d_val;    break;
 349                 case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;
 350                 case DT_RELA:   rela = (void*)(iBaseDiff + dynamicTab[j].d_val);        break;
 351                 case DT_RELASZ: relaSz = dynamicTab[j].d_val;   break;
 352                 case DT_RELAENT:        relaEntSz = dynamicTab[j].d_val;        break;
 353
 354                 // --- Symbol Table ---
 355                 case DT_SYMTAB:
 356                 // --- Hash Table ---
 357                 case DT_HASH:
 358                 // --- String Table ---
 359                 case DT_STRTAB:
 360                         break;
 361
 362                 // --- Unknown ---
 363                 default:
 364                         if(dynamicTab[j].d_tag > DT_JMPREL)     continue;
 365                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 366                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 367                         break;
 368                 }
 369         }
 370
 371         DEBUGS(" elf_relocate: Beginning Relocation");
 372
 373          int    fail = 0;
 374
 375         switch(hdr->machine)
 376         {
 377         case EM_386:
 378                 do_relocate = elf_doRelocate_386;
 379                 break;
 380         case EM_ARM:
 381                 do_relocate = elf_doRelocate_arm;
 382                 break;
 383         default:
 384                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 385                 do_relocate = elf_doRelocate_unk;
 386                 fail = 1;
 387                 break;
 388         }
 389
 390         DEBUGS("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
 391
 392         #define _doRelocate(r_info, ptr, bRela, addend) \
 393                 do_relocate(r_info, ptr, addend, ELF32_R_TYPE(r_info), bRela, \
 394                         dynstrtab + dynsymtab[ELF32_R_SYM(r_info)].nameOfs, iBaseDiff);
 395
 396         // Parse Relocation Entries
 397         if(rel && relSz)
 398         {
 399                 Elf32_Word      *ptr;
 400                 DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 401                 j = relSz / relEntSz;
 402                 for( i = 0; i < j; i++ )
 403                 {
 404                         //DEBUGS("  Rel %i: 0x%x+0x%x", i, iBaseDiff, rel[i].r_offset);
 405                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 406                         fail |= _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 407                 }
 408         }
 409         // Parse Relocation Entries
 410         if(rela && relaSz)
 411         {
 412                 Elf32_Word      *ptr;
 413                 DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 414                 j = relaSz / relaEntSz;
 415                 for( i = 0; i < j; i++ )
 416                 {
 417                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 418                         fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 419                 }
 420         }
 421
 422         // === Process PLT (Procedure Linkage Table) ===
 423         if(plt && pltSz)
 424         {
 425                 Elf32_Word      *ptr;
 426                 DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x", plt);
 427                 if(pltType == DT_REL)
 428                 {
 429                         Elf32_Rel       *pltRel = plt;
 430                         j = pltSz / sizeof(Elf32_Rel);
 431                         DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries", j);
 432                         for(i=0;i<j;i++)
 433                         {
 434                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 435                                 fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 436                         }
 437                 }
 438                 else
 439                 {
 440                         Elf32_Rela      *pltRela = plt;
 441                         j = pltSz / sizeof(Elf32_Rela);
 442                         DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries", j);
 443                         for(i=0;i<j;i++)
 444                         {
 445                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 446                                 fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 447                         }
 448                 }
 449         }
 450
 451         // Re-set readonly
 452         for( i = 0; i < iSegmentCount; i ++ )
 453         {
 454                 // If load and not writable
 455                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 456                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 457                         uintptr_t       end = addr + phtab[i].MemSize;
 458                         for( ; addr < end; addr += PAGE_SIZE )
 459                                 _SysSetMemFlags(addr, 1, 1);    // Unset RO
 460                 }
 461         }
 462
 463         if( fail ) {
 464                 DEBUGS("ElfRelocate: Failure");
 465                 return NULL;
 466         }
 467
 468         #undef _doRelocate
 469
 470         DEBUGS("ElfRelocate: RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 471         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 472 }
 473
 474 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 475 {
 476         Elf32_Ehdr      *hdr = Base;
 477         Elf32_Sym       *symtab = NULL;
 478          int    nbuckets = 0;
 479         Elf32_Word      *pBuckets = NULL;
 480         Elf32_Word      *pChains;
 481         uint32_t        iNameHash;
 482         const char      *dynstrtab = NULL;
 483         uintptr_t       iBaseDiff = -1;
 484         Elf32_Phdr      *phtab;
 485         Elf32_Dyn       *dynTab = NULL;
 486          int    i;
 487
 488         // Locate the tables
 489         phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 490         for( i = 0; i < hdr->phentcount; i ++ )
 491         {
 492                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 493                         iBaseDiff = phtab[i].VAddr;
 494                 if( phtab[i].Type == PT_DYNAMIC ) {
 495                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 496                 }
 497         }
 498         if( !dynTab ) {
 499                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 500                 return 0;
 501         }
 502         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 503         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 504         for( i = 0; dynTab[i].d_tag != DT_NULL; i++)
 505         {
 506                 switch(dynTab[i].d_tag)
 507                 {
 508                 // --- Symbol Table ---
 509                 case DT_SYMTAB:
 510                         symtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);        // Rebased in Relocate
 511                         break;
 512                 case DT_STRTAB:
 513                         dynstrtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 514                         break;
 515                 // --- Hash Table --
 516                 case DT_HASH:
 517                         pBuckets = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 518                         break;
 519                 }
 520         }
 521
 522         if( !symtab ) {
 523                 SysDebug("ERRO - No DT_SYMTAB in %p", Base);
 524                 return 0;
 525         }
 526         if( !pBuckets ) {
 527                 SysDebug("ERRO - No DT_HASH in %p", Base);
 528                 return 0;
 529         }
 530         if( !dynstrtab ) {
 531                 SysDebug("ERRO - No DT_STRTAB in %p", Base);
 532                 return 0;
 533         }
 534
 535         // ... ok... maybe they haven't been relocated
 536         if( (uintptr_t)symtab < (uintptr_t)Base )
 537         {
 538                 symtab    = (void*)( (uintptr_t)symtab    + iBaseDiff );
 539                 pBuckets  = (void*)( (uintptr_t)pBuckets  + iBaseDiff );
 540                 dynstrtab = (void*)( (uintptr_t)dynstrtab + iBaseDiff );
 541                 SysDebug("Executable not yet relocated");
 542         }
 543
 544         nbuckets = pBuckets[0];
 545 //      iSymCount = pBuckets[1];
 546         pBuckets = &pBuckets[2];
 547         pChains = &pBuckets[ nbuckets ];
 548
 549         // Get hash
 550         iNameHash = ElfHashString(Name);
 551         iNameHash %= nbuckets;
 552
 553         // Walk Chain
 554         i = pBuckets[ iNameHash ];
 555         if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].nameOfs, Name) == 0) {
 556                 *ret = (void*)( (uintptr_t) symtab[ i ].value + iBaseDiff );
 557                 if(Size)        *Size = symtab[i].size;
 558                 return 1;
 559         }
 560
 561         while(pChains[i] != STN_UNDEF)
 562         {
 563                 i = pChains[i];
 564                 if(symtab[i].shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[ i ].nameOfs, Name) == 0) {
 565                         *ret = (void*)( (uintptr_t)symtab[ i ].value + iBaseDiff );
 566                         if(Size)        *Size = symtab[i].size;
 567                         return 1;
 568                 }
 569         }
 570
 571         return 0;
 572 }
 573
 574 #ifdef SUPPORT_ELF64
 575 typedef int (*t_elf64_doreloc)(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
 576
 577 int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 578 {
 579          int    sym = ELF64_R_SYM(r_info);
 580          int    type = ELF64_R_TYPE(r_info);
 581         const char      *symname = strtab + symtab[sym].st_name;
 582         void    *symval;
 583         //DEBUGS("_Elf64DoReloc: %s", symname);
 584         switch( type )
 585         {
 586         case R_X86_64_NONE:
 587                 break;
 588         case R_X86_64_64:
 589                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 590                 *(uint64_t*)ptr = (uintptr_t)symval + addend;
 591                 break;
 592         case R_X86_64_COPY: {
 593                 size_t  size;
 594                 if( !GetSymbol(symname, &symval, &size)  )      return 1;
 595                 memcpy(ptr, symval, size);
 596                 } break;
 597         case R_X86_64_GLOB_DAT:
 598                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 599                 *(uint64_t*)ptr = (uintptr_t)symval;
 600                 break;
 601         case R_X86_64_JUMP_SLOT:
 602                 if( !GetSymbol(symname, &symval, NULL)  )       return 1;
 603                 *(uint64_t*)ptr = (uintptr_t)symval;
 604                 break;
 605         case R_X86_64_RELATIVE:
 606                 *(uint64_t*)ptr = (uintptr_t)Base + addend;
 607                 break;
 608         default:
 609                 SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 610                 return 2;
 611         }
 612         //DEBUGS("_Elf64DoReloc: - Good");
 613         return 0;
 614 }
 615
 616 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 617 {
 618          int    i;
 619         Elf64_Ehdr      *hdr = Base;
 620         Elf64_Phdr      *phtab;
 621         Elf64_Dyn       *dyntab = NULL;
 622         Elf64_Addr      compiledBase = -1, baseDiff;
 623         Elf64_Sym       *symtab = NULL;
 624         char    *strtab = NULL;
 625         Elf64_Word      *hashtab = NULL;
 626         Elf64_Rel       *rel = NULL;
 627          int    rel_count = 0;
 628         Elf64_Rela      *rela = NULL;
 629          int    rela_count = 0;
 630         void    *pltrel = NULL;
 631          int    plt_size = 0, plt_type = 0;
 632
 633         DEBUGS("Elf64Relocate: hdr = {");
 634         DEBUGS("Elf64Relocate:  e_ident = '%.16s'", hdr->e_ident);
 635         DEBUGS("Elf64Relocate:  e_type = 0x%x", hdr->e_type);
 636         DEBUGS("Elf64Relocate:  e_machine = 0x%x", hdr->e_machine);
 637         DEBUGS("Elf64Relocate:  e_version = 0x%x", hdr->e_version);
 638         DEBUGS("Elf64Relocate:  e_entry = %p", hdr->e_entry);
 639         DEBUGS("Elf64Relocate:  e_phoff = 0x%llx", hdr->e_phoff);
 640         DEBUGS("Elf64Relocate:  e_shoff = 0x%llx", hdr->e_shoff);
 641         DEBUGS("Elf64Relocate:  e_flags = 0x%x", hdr->e_flags);
 642         DEBUGS("Elf64Relocate:  e_ehsize = 0x%x", hdr->e_ehsize);
 643         DEBUGS("Elf64Relocate:  e_phentsize = 0x%x", hdr->e_phentsize);
 644         DEBUGS("Elf64Relocate:  e_phnum = %i", hdr->e_phnum);
 645
 646         // Scan for the dynamic table (and find the compiled base)
 647         phtab = (void*)((uintptr_t)Base + (uintptr_t)hdr->e_phoff);
 648         for( i = 0; i < hdr->e_phnum; i ++ )
 649         {
 650                 if(phtab[i].p_type == PT_DYNAMIC)
 651                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 652                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 653                         compiledBase = phtab[i].p_vaddr;
 654         }
 655
 656         baseDiff = (uintptr_t)Base - compiledBase;
 657
 658         DEBUGS("baseDiff = %p", baseDiff);
 659
 660         if(dyntab == NULL) {
 661                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 662                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 663         }
 664
 665         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 666
 667         // Parse the dynamic table (first pass)
 668         // - Search for String, Symbol and Hash tables
 669         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 670         {
 671                 switch(dyntab[i].d_tag)
 672                 {
 673                 case DT_SYMTAB:
 674                         dyntab[i].d_un.d_ptr += baseDiff;
 675                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 676                         break;
 677                 case DT_STRTAB:
 678                         dyntab[i].d_un.d_ptr += baseDiff;
 679                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 680                         break;
 681                 case DT_HASH:
 682                         dyntab[i].d_un.d_ptr += baseDiff;
 683                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 684                         break;
 685                 }
 686         }
 687
 688         if( !symtab || !strtab || !hashtab ) {
 689                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 690                 return NULL;
 691         }
 692
 693         // Ready for symbol use
 694         AddLoaded( Filename, Base );
 695
 696         // Second pass on dynamic table
 697         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 698         {
 699                 DEBUGS("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 700                 switch(dyntab[i].d_tag)
 701                 {
 702                 case DT_SONAME: break;
 703
 704                 case DT_NEEDED: {
 705                         char *libPath = strtab + dyntab[i].d_un.d_val;
 706                         DEBUGS("Elf64Relocate: libPath = '%s'", libPath);
 707                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 708                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 709                                 return NULL;
 710                         }
 711                         } break;
 712
 713                 // Relocation entries
 714                 case DT_REL:
 715                         dyntab[i].d_un.d_ptr += baseDiff;
 716                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 717                         break;
 718                 case DT_RELSZ:
 719                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 720                         break;
 721                 case DT_RELENT:
 722                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 723                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 724                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 725                                 return NULL;
 726                         }
 727                         break;
 728                 case DT_RELA:
 729                         dyntab[i].d_un.d_ptr += baseDiff;
 730                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 731                         break;
 732                 case DT_RELASZ:
 733                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 734                         break;
 735                 case DT_RELAENT:
 736                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 737                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 738                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 739                                 return NULL;
 740                         }
 741                         break;
 742                 case DT_JMPREL:
 743                         dyntab[i].d_un.d_ptr += baseDiff;
 744                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 745                         break;
 746                 case DT_PLTREL:
 747                         plt_type = dyntab[i].d_un.d_val;
 748                         break;
 749                 case DT_PLTRELSZ:
 750                         plt_size = dyntab[i].d_un.d_val;
 751                         break;
 752                 }
 753         }
 754
 755         // Relocation function
 756         t_elf64_doreloc fpElf64DoReloc = &_Elf64DoReloc_X86_64;
 757         #define _Elf64DoReloc(info, ptr, addend)        fpElf64DoReloc(Base, strtab, symtab, info, ptr, addend)
 758
 759         int fail = 0;
 760         if( rel )
 761         {
 762                 DEBUGS("rel_count = %i", rel_count);
 763                 for( i = 0; i < rel_count; i ++ )
 764                 {
 765                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 766                         fail |= _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 767                 }
 768         }
 769
 770         if( rela )
 771         {
 772                 DEBUGS("rela_count = %i", rela_count);
 773                 for( i = 0; i < rela_count; i ++ )
 774                 {
 775                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 776                         fail |= _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 777                 }
 778         }
 779
 780         if( pltrel && plt_type )
 781         {
 782                 if( plt_type == DT_REL ) {
 783                         Elf64_Rel       *plt = pltrel;
 784                          int    count = plt_size / sizeof(Elf64_Rel);
 785                         DEBUGS("plt rel count = %i", count);
 786                         for( i = 0; i < count; i ++ )
 787                         {
 788                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 789                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 790                         }
 791                 }
 792                 else {
 793                         Elf64_Rela      *plt = pltrel;
 794                          int    count = plt_size / sizeof(Elf64_Rela);
 795                         DEBUGS("plt rela count = %i", count);
 796                         for( i = 0; i < count; i ++ )
 797                         {
 798                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 799                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 800                         }
 801                 }
 802         }
 803
 804         if( fail ) {
 805                 DEBUGS("Elf64Relocate: Failure");
 806                 return NULL;
 807         }
 808
 809         {
 810         void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 811         DEBUGS("Elf64Relocate: Relocations done, return %p", ret);
 812         return ret;
 813         }
 814 }
 815
 816 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 817 {
 818         Elf64_Ehdr      *hdr = Base;
 819         Elf64_Sym       *symtab;
 820          int    nbuckets = 0;
 821 //       int    iSymCount = 0;
 822          int    i;
 823         Elf64_Word      *pBuckets;
 824         Elf64_Word      *pChains;
 825         uint32_t        iNameHash;
 826         const char      *dynstrtab;
 827         uintptr_t       iBaseDiff = -1;
 828
 829         dynstrtab = NULL;
 830         pBuckets = NULL;
 831         symtab = NULL;
 832
 833         // Catch the current executable
 834         if( !pBuckets )
 835         {
 836                 Elf64_Phdr      *phtab;
 837                 Elf64_Dyn       *dynTab = NULL;
 838                  int    j;
 839
 840                 // Locate the tables
 841                 phtab = (void*)( (intptr_t)Base + (uintptr_t)hdr->e_phoff );
 842                 for( i = 0; i < hdr->e_phnum; i ++ )
 843                 {
 844                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 845                                 iBaseDiff = phtab[i].p_vaddr;
 846                         if( phtab[i].p_type == PT_DYNAMIC ) {
 847                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 848                         }
 849                 }
 850                 if( !dynTab ) {
 851                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 852                         return 0;
 853                 }
 854                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 855                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 856
 857                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 858                 {
 859                         switch(dynTab[j].d_tag)
 860                         {
 861                         // --- Symbol Table ---
 862                         case DT_SYMTAB:
 863                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 864                                 break;
 865                         case DT_STRTAB:
 866                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 867                                 break;
 868                         // --- Hash Table --
 869                         case DT_HASH:
 870                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 871                                 break;
 872                         }
 873                 }
 874         }
 875
 876         nbuckets = pBuckets[0];
 877 //      iSymCount = pBuckets[1];
 878         pBuckets = &pBuckets[2];
 879         pChains = &pBuckets[ nbuckets ];
 880
 881         // Get hash
 882         iNameHash = ElfHashString(Name);
 883         iNameHash %= nbuckets;
 884
 885         // Walk Chain
 886         i = pBuckets[ iNameHash ];
 887         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 888                 *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
 889                 if(Size)        *Size = symtab[i].st_size;
 890                 DEBUGS("%s = %p", Name, *Ret);
 891                 return 1;
 892         }
 893
 894         while(pChains[i] != STN_UNDEF)
 895         {
 896                 i = pChains[i];
 897                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
 898                         *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
 899                         if(Size)        *Size = symtab[i].st_size;
 900                         DEBUGS("%s = %p", Name, *Ret);
 901                         return 1;
 902                 }
 903         }
 904
 905         return 0;
 906 }
 907 #endif
 908
 909
 910 uint32_t ElfHashString(const char *name)
 911 {
 912         uint32_t        h = 0, g;
 913         while(*name)
 914         {
 915                 h = (h << 4) + *(uint8_t*)name++;
 916                 if( (g = h & 0xf0000000) )
 917                         h ^= g >> 24;
 918                 h &= ~g;
 919         }
 920         return h;
 921 }
 922