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

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