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

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