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 #ifndef assert
  19 # include <assert.h>
  20 #endif
  21 #include "elf32.h"
  22 #include "elf64.h"
  23
  24 #if DEBUG
  25 # define DEBUG_OUT(...) SysDebug(__VA_ARGS__)
  26 #else
  27 # define DEBUG_OUT(...) do{}while(0)    //((void)(__VA_ARGS__))
  28 #endif
  29
  30 #define WARNING(f,...)  SysDebug("WARN: "f ,## __VA_ARGS__)     // Malformed file
  31 #define NOTICE(f,...)   SysDebug("NOTICE: "f ,## __VA_ARGS__)   // Missing relocation
  32 #define TRACE(f,...)    DEBUG_OUT("TRACE:%s:%i "f, __func__, __LINE__ ,## __VA_ARGS__)  // Debugging trace
  33
  34 #ifndef DISABLE_ELF64
  35 # define SUPPORT_ELF64
  36 #endif
  37
  38 typedef struct
  39 {
  40         void    *Base;
  41         intptr_t        iBaseDiff;
  42         const char      *strtab;
  43         Elf32_Sym       *symtab;
  44 } tElfRelocInfo;
  45
  46 typedef int tElf32RelocFcn(tElfRelocInfo *Info, uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int bRela);
  47
  48 // === CONSTANTS ===
  49 #if DEBUG
  50 //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"};
  51 //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"};
  52 #endif
  53
  54 // === PROTOTYPES ===
  55 void    *ElfRelocate(void *Base, char **envp, const char *Filename);
  56  int    ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  57 void    *Elf32Relocate(void *Base, char **envp, const char *Filename);
  58  int    Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff);
  59  int    Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type);
  60  int    Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  61 tElf32RelocFcn  elf_doRelocate_386;
  62 tElf32RelocFcn  elf_doRelocate_arm;
  63 tElf32RelocFcn  elf_doRelocate_unk;
  64 #ifdef SUPPORT_ELF64
  65 int     _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
  66 void    *Elf64Relocate(void *Base, char **envp, const char *Filename);
  67  int    Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
  68 #endif
  69  int    Elf32GetSymbolReloc(tElfRelocInfo *Info, const Elf32_Sym *Symbol, void **Ret, size_t *Size);
  70 uint32_t        ElfHashString(const char *name);
  71
  72 // === CODE ===
  73 /**
  74  * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
  75  * \brief Relocates a loaded ELF Executable
  76  */
  77 void *ElfRelocate(void *Base, char **envp, const char *Filename)
  78 {
  79         Elf32_Ehdr      *hdr = Base;
  80
  81         switch(hdr->e_ident[4])
  82         {
  83         case ELFCLASS32:
  84                 return Elf32Relocate(Base, envp, Filename);
  85 #ifdef SUPPORT_ELF64
  86         case ELFCLASS64:
  87                 return Elf64Relocate(Base, envp, Filename);
  88 #endif
  89         default:
  90                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
  91                 return NULL;
  92         }
  93 }
  94
  95 /**
  96  * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
  97  */
  98 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
  99 {
 100         Elf32_Ehdr      *hdr = Base;
 101
 102         switch(hdr->e_ident[4])
 103         {
 104         case ELFCLASS32:
 105                 return Elf32GetSymbol(Base, Name, ret, Size);
 106 #ifdef SUPPORT_ELF64
 107         case ELFCLASS64:
 108                 return Elf64GetSymbol(Base, Name, ret, Size);
 109 #endif
 110         default:
 111                 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
 112                 return 0;
 113         }
 114 }
 115
 116 int elf_doRelocate_386(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
 117 {
 118         const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
 119         void    *symval = (void*)sym->st_value;
 120         size_t  size = sym->st_size;
 121         TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
 122         switch( ELF32_R_TYPE(r_info) )
 123         {
 124         // Standard 32 Bit Relocation (S+A)
 125         case R_386_32:
 126                 TRACE("R_386_32 *0x%x = %p + 0x%x", ptr, symval, addend);
 127                 *ptr = (intptr_t)symval + addend;
 128                 break;
 129
 130         // 32 Bit Relocation wrt. Offset (S+A-P)
 131         case R_386_PC32:
 132                 TRACE("R_386_PC32 *0x%x = 0x%x + 0x%p - 0x%x", ptr, *ptr, symval, (intptr_t)ptr );
 133                 *ptr = (intptr_t)symval + addend - (intptr_t)ptr;
 134                 //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
 135                 break;
 136
 137         // Absolute Value of a symbol (S)
 138         case R_386_GLOB_DAT:
 139                 TRACE("R_386_GLOB_DAT *0x%x = %p", ptr, symval);        if(0)
 140         case R_386_JMP_SLOT:
 141                 TRACE("R_386_JMP_SLOT *0x%x = %p", ptr, symval);
 142                 *ptr = (intptr_t)symval;
 143                 break;
 144
 145         // Base Address (B+A)
 146         case R_386_RELATIVE:
 147                 TRACE("R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, Info->iBaseDiff, addend);
 148                 *ptr = Info->iBaseDiff + addend;
 149                 break;
 150
 151         case R_386_COPY: {
 152                 void *old_symval = symval;
 153                 GetSymbol(Info->strtab + sym->st_name, &symval, &size, Info->Base);
 154                 if( symval == old_symval ) {
 155                         WARNING("Can't find required external symbol '%s'", Info->strtab + sym->st_name);
 156                         return 1;
 157                 }
 158                 TRACE("R_386_COPY (%p, %p, %i)", ptr, symval, size);
 159                 memcpy(ptr, symval, size);
 160                 break; }
 161
 162         default:
 163                 WARNING("Unknown relocation %i", ELF32_ST_TYPE(r_info));
 164                 return 2;
 165         }
 166         return 0;
 167 }
 168
 169 int elf_doRelocate_arm(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
 170 {
 171         const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
 172         void    *symval = (void*)sym->st_value;
 173         size_t  size = sym->st_size;
 174         TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
 175         uintptr_t       val = (uintptr_t)symval;
 176         switch( ELF32_R_TYPE(r_info) )
 177         {
 178         // (S + A) | T
 179         case R_ARM_ABS32:
 180                 TRACE("R_ARM_ABS32 %p (%p + %x)", ptr, symval, addend);
 181                 *ptr = val + addend;
 182                 break;
 183         case R_ARM_GLOB_DAT:
 184                 TRACE("R_ARM_GLOB_DAT %p (%p + %x)", ptr, symval, addend);
 185                 *ptr = val + addend;
 186                 break;
 187         case R_ARM_JUMP_SLOT:
 188                 if(!bRela)      addend = 0;
 189                 TRACE("R_ARM_JUMP_SLOT %p (%p + %x)", ptr, symval, addend);
 190                 *ptr = val + addend;
 191                 break;
 192         // Copy
 193         case R_ARM_COPY:
 194                 TRACE("R_ARM_COPY (%p, %p, %i)", ptr, symval, size);
 195                 memcpy(ptr, symval, size);
 196                 break;
 197         // Delta between link and runtime locations + A
 198         case R_ARM_RELATIVE:
 199                 TRACE("R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, Info->iBaseDiff, addend);
 200                 if(ELF32_R_SYM(r_info) != 0) {
 201                         // TODO: Get delta for a symbol
 202                         WARNING("TODO - Implment R_ARM_RELATIVE for symbols");
 203                         return 2;
 204                 }
 205                 else {
 206                         *ptr = Info->iBaseDiff + addend;
 207                 }
 208                 break;
 209         default:
 210                 WARNING("Unknown Relocation, %i", ELF32_R_TYPE(r_info));
 211                 return 2;
 212         }
 213         return 0;
 214 }
 215
 216 int elf_doRelocate_unk(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
 217 {
 218         return 1;
 219 }
 220
 221 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
 222 {
 223         const Elf32_Ehdr        *hdr = Base;
 224         char    *libPath;
 225         intptr_t        iRealBase = -1;
 226         intptr_t        iBaseDiff;
 227         Elf32_Rel       *rel = NULL;
 228         Elf32_Rela      *rela = NULL;
 229         void    *plt = NULL;
 230          int    relSz=0, relEntSz=8;
 231          int    relaSz=0, relaEntSz=8;
 232          int    pltSz=0, pltType=0;
 233         Elf32_Dyn       *dynamicTab = NULL;     // Dynamic Table Pointer
 234
 235         TRACE("(Base=0x%x)", Base);
 236
 237         // Check magic header
 238
 239
 240         // Parse Program Header to get Dynamic Table
 241         // - Determine the linked base of the executable
 242         const Elf32_Phdr        *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 243         const int iSegmentCount = hdr->phentcount;
 244         for(int i = 0; i < iSegmentCount; i ++)
 245         {
 246                 switch(phtab[i].Type)
 247                 {
 248                 case PT_LOAD:
 249                         // Determine linked base address
 250                         if( iRealBase > phtab[i].VAddr)
 251                                 iRealBase = phtab[i].VAddr;
 252                         break;
 253                 case PT_DYNAMIC:
 254                         // Find Dynamic Section
 255                         if(!dynamicTab) {
 256                                 dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
 257                         }
 258                         else {
 259                                 WARNING("elf_relocate: Multiple PT_DYNAMIC segments");
 260                         }
 261                         break;
 262                 }
 263         }
 264
 265         // Page Align real base
 266         iRealBase &= ~0xFFF;
 267         TRACE("True Base = 0x%x, Compiled Base = 0x%x", Base, iRealBase);
 268
 269         // Adjust "Real" Base
 270         iBaseDiff = (intptr_t)Base - iRealBase;
 271
 272         // Check if a PT_DYNAMIC segement was found
 273         if(!dynamicTab) {
 274                 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 275                 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
 276         }
 277
 278         // Allow writing to read-only segments, just in case they need to be relocated
 279         // - Will be reversed at the end of the function
 280         for( int i = 0; i < iSegmentCount; i ++ )
 281         {
 282                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 283                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 284                         uintptr_t       end = addr + phtab[i].MemSize;
 285                         for( ; addr < end; addr += PAGE_SIZE )
 286                                 _SysSetMemFlags(addr, 0, 1);    // Unset RO
 287                 }
 288         }
 289
 290         // Adjust Dynamic Table
 291         dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
 292
 293         // === Get Symbol table and String Table ===
 294         char    *dynstrtab = NULL;      // .dynamic String Table
 295         Elf32_Sym       *dynsymtab = NULL;
 296         Elf32_Word      *hashtable = NULL;
 297          int    iSymCount = 0;
 298         for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 299         {
 300                 const Elf32_Dyn *dt = &dynamicTab[j];
 301                 switch(dt->d_tag)
 302                 {
 303                 // --- Symbol Table ---
 304                 case DT_SYMTAB:
 305                         TRACE("DYNAMIC Symbol Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
 306                         dynsymtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
 307                         break;
 308                 // --- String Table ---
 309                 case DT_STRTAB:
 310                         TRACE("DYNAMIC String Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
 311                         dynstrtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
 312                         break;
 313                 // --- Hash Table --
 314                 case DT_HASH:
 315                         TRACE("DYNAMIC Hash table %p (%p)", dt->d_val, dt->d_val + iBaseDiff);
 316                         hashtable = (void*)((intptr_t)dt->d_val + iBaseDiff);
 317                         iSymCount = hashtable[1];
 318                         break;
 319                 }
 320         }
 321
 322         if(dynsymtab == NULL) {
 323                 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
 324                 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
 325         }
 326
 327         // Apply base offset to locally defined symbols
 328         // - #0 is defined as ("" SHN_UNDEF), so skip it
 329         for( int i = 1; i < iSymCount; i ++ )
 330         {
 331                 Elf32_Sym       *sym = &dynsymtab[i];
 332                 const char *name = dynstrtab + sym->st_name;
 333                 (void)name;
 334                 if( sym->st_shndx == SHN_UNDEF )
 335                 {
 336                         TRACE("Sym %i'%s' deferred (SHN_UNDEF)", i, name);
 337                 }
 338                 else if( sym->st_shndx == SHN_ABS )
 339                 {
 340                         // Leave as is
 341                         SysDebug("Sym %i'%s' untouched", i, name);
 342                 }
 343                 else
 344                 {
 345                         // TODO: What about weak locally-defined symbols?
 346                         if( ELF32_ST_BIND(sym->st_info) == STB_WEAK )
 347                         {
 348                                 WARNING("TODO: Weak bound local symbols '%s'", name);
 349                                 assert(ELF32_ST_BIND(sym->st_info) != STB_WEAK);
 350                                 return NULL;
 351                         }
 352                         TRACE("Sym %i'%s' %p += 0x%x", i, name, sym->st_value, iBaseDiff);
 353                         sym->st_value += iBaseDiff;
 354                 }
 355         }
 356
 357         // === Add to loaded list (can be imported now) ===
 358         AddLoaded( Filename, Base );
 359
 360         // === Parse Relocation Data ===
 361         TRACE("dynamicTab = 0x%x", dynamicTab);
 362         for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 363         {
 364                 const Elf32_Dyn *dt = &dynamicTab[j];
 365                 switch(dt->d_tag)
 366                 {
 367                 // --- Shared Library Name ---
 368                 case DT_SONAME:
 369                         TRACE(".so Name '%s'", dynstrtab + dt->d_val);
 370                         break;
 371                 // --- Needed Library ---
 372                 case DT_NEEDED:
 373                         //assert(dt->d_val <= sizeof_dynstrtab);
 374                         libPath = dynstrtab + dt->d_val;
 375                         TRACE(" Required Library '%s'", libPath);
 376                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 377                                 SysDebug("Unable to load required library '%s'", libPath);
 378                                 return 0;
 379                         }
 380                         TRACE(" Lib loaded");
 381                         break;
 382                 // --- PLT/GOT ---
 383 //              case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dt->d_val);        break;
 384                 case DT_JMPREL: plt = (void*)(iBaseDiff + dt->d_val);   break;
 385                 case DT_PLTREL: pltType = dt->d_val;    break;
 386                 case DT_PLTRELSZ:       pltSz = dt->d_val;      break;
 387
 388                 // --- Relocation ---
 389                 case DT_REL:    rel = (void*)(iBaseDiff + dt->d_val);   break;
 390                 case DT_RELSZ:  relSz = dt->d_val;      break;
 391                 case DT_RELENT: relEntSz = dt->d_val;   break;
 392                 case DT_RELA:   rela = (void*)(iBaseDiff + dt->d_val);  break;
 393                 case DT_RELASZ: relaSz = dt->d_val;     break;
 394                 case DT_RELAENT:        relaEntSz = dt->d_val;  break;
 395
 396                 // --- Symbol Table ---
 397                 case DT_SYMTAB:
 398                 // --- Hash Table ---
 399                 case DT_HASH:
 400                 // --- String Table ---
 401                 case DT_STRTAB:
 402                         break;
 403
 404                 // --- Unknown ---
 405                 default:
 406                         if(dt->d_tag > DT_JMPREL)       continue;
 407                         //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
 408                         //      i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
 409                         break;
 410                 }
 411         }
 412
 413         // Resolve symbols (second pass)
 414         // - #0 is defined as ("" SHN_UNDEF), so skip it
 415          int    fail = 0;
 416         for( int i = 1; i < iSymCount; i ++ )
 417         {
 418                 Elf32_Sym       *sym = &dynsymtab[i];
 419                 const char *name = dynstrtab + sym->st_name;
 420                 if( sym->st_shndx == SHN_UNDEF )
 421                 {
 422                         void *newval;
 423                         size_t  newsize;
 424                         if( !GetSymbol(name, &newval, &newsize, Base) ) {
 425                                 if( ELF32_ST_BIND(sym->st_info) != STB_WEAK ) {
 426                                         // Not a weak binding, set fail and move on
 427                                         WARNING("Elf32Relocate: Can't find required symbol '%s' for '%s'",
 428                                                 name, Filename);
 429                                         fail = 1;
 430                                         continue ;
 431                                 }
 432                                 // Leave the symbol value as-is
 433                         }
 434                         else {
 435                                 TRACE("Sym %i'%s' bound to %p+0x%x", i, name, newval, newsize);
 436                                 sym->st_value = (intptr_t)newval;
 437                                 sym->st_size = newsize;
 438                         }
 439                 }
 440                 else if( sym->st_shndx == SHN_ABS )
 441                 {
 442                         // Leave as is
 443                 }
 444                 else
 445                 {
 446                         // Handled previously
 447                         // TODO: What about weak locally-defined symbols?
 448                         assert( ELF32_ST_BIND(sym->st_info) != STB_WEAK );
 449                 }
 450         }
 451         if( fail ) {
 452                 WARNING("Relocation of '%s' failed", Filename);
 453                 return NULL;
 454         }
 455
 456         TRACE("Beginning Relocation on '%s'", Filename);
 457
 458
 459         tElf32RelocFcn  *do_relocate;
 460         switch(hdr->machine)
 461         {
 462         case EM_386:
 463                 do_relocate = elf_doRelocate_386;
 464                 break;
 465         case EM_ARM:
 466                 do_relocate = elf_doRelocate_arm;
 467                 break;
 468         default:
 469                 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
 470                 do_relocate = elf_doRelocate_unk;
 471                 fail = 1;
 472                 break;
 473         }
 474
 475         TRACE("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
 476
 477         #define _doRelocate(r_info, ptr, bRela, addend) \
 478                 do_relocate(&reloc_info, r_info, ptr, addend, bRela);
 479
 480         tElfRelocInfo   reloc_info = {
 481                 .Base = Base,
 482                 .iBaseDiff = iBaseDiff,
 483                 .strtab = dynstrtab,
 484                 .symtab = dynsymtab
 485         };
 486
 487         // Parse Relocation Entries
 488         if(rel && relSz)
 489         {
 490                 Elf32_Word      *ptr;
 491                 TRACE("rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
 492                 int max = relSz / relEntSz;
 493                 for( int i = 0; i < max; i++ )
 494                 {
 495                         ptr = (void*)(iBaseDiff + rel[i].r_offset);
 496                         fail |= _doRelocate(rel[i].r_info, ptr, 0, *ptr);
 497                 }
 498         }
 499         // Parse Relocation Entries
 500         if(rela && relaSz)
 501         {
 502                 Elf32_Word      *ptr;
 503                 TRACE("rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
 504                 int count = relaSz / relaEntSz;
 505                 for( int i = 0; i < count; i++ )
 506                 {
 507                         ptr = (void*)(iBaseDiff + rela[i].r_offset);
 508                         fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
 509                 }
 510         }
 511
 512         // === Process PLT (Procedure Linkage Table) ===
 513         if(plt && pltSz)
 514         {
 515                 Elf32_Word      *ptr;
 516                 TRACE("Relocate PLT, plt=0x%x", plt);
 517                 if(pltType == DT_REL)
 518                 {
 519                         Elf32_Rel       *pltRel = plt;
 520                         int count = pltSz / sizeof(Elf32_Rel);
 521                         TRACE("PLT Reloc Type = Rel, %i entries", count);
 522                         for(int i = 0; i < count; i ++)
 523                         {
 524                                 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
 525                                 fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
 526                         }
 527                 }
 528                 else
 529                 {
 530                         Elf32_Rela      *pltRela = plt;
 531                         int count = pltSz / sizeof(Elf32_Rela);
 532                         TRACE("PLT Reloc Type = Rela, %i entries", count);
 533                         for(int i=0;i<count;i++)
 534                         {
 535                                 ptr = (void*)(iRealBase + pltRela[i].r_offset);
 536                                 fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
 537                         }
 538                 }
 539         }
 540
 541         // Re-set readonly
 542         for( int i = 0; i < iSegmentCount; i ++ )
 543         {
 544                 // If load and not writable
 545                 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
 546                         uintptr_t       addr = phtab[i].VAddr + iBaseDiff;
 547                         uintptr_t       end = addr + phtab[i].MemSize;
 548                         for( ; addr < end; addr += PAGE_SIZE )
 549                                 _SysSetMemFlags(addr, 1, 1);    // Unset RO
 550                 }
 551         }
 552
 553         if( fail ) {
 554                 TRACE("ElfRelocate: Failure");
 555                 return NULL;
 556         }
 557
 558         #undef _doRelocate
 559
 560         TRACE("RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
 561         return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
 562 }
 563
 564 int Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff)
 565 {
 566         Elf32_Dyn       *dynTab = NULL;
 567         uintptr_t       iBaseDiff = -1;
 568         Elf32_Ehdr *hdr = Base;
 569         Elf32_Phdr *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
 570         for( int i = 0; i < hdr->phentcount; i ++ )
 571         {
 572                 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
 573                         iBaseDiff = phtab[i].VAddr;
 574                 if( phtab[i].Type == PT_DYNAMIC ) {
 575                         dynTab = (void*)(intptr_t)phtab[i].VAddr;
 576                 }
 577         }
 578         if( !dynTab ) {
 579                 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 580                 return 1;
 581         }
 582         iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 583         dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 584         for( int i = 0; dynTab[i].d_tag != DT_NULL; i++)
 585         {
 586                 switch(dynTab[i].d_tag)
 587                 {
 588                 // --- Symbol Table ---
 589                 case DT_SYMTAB:
 590                         *symtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);       // Rebased in Relocate
 591                         break;
 592                 case DT_STRTAB:
 593                         *dynstrtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 594                         break;
 595                 // --- Hash Table --
 596                 case DT_HASH:
 597                         *pBuckets = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
 598                         break;
 599                 }
 600         }
 601
 602         if( !*symtab ) {
 603                 SysDebug("ERRO - No DT_SYMTAB in %p", Base);
 604                 return 1;
 605         }
 606         if( !*pBuckets ) {
 607                 SysDebug("ERRO - No DT_HASH in %p", Base);
 608                 return 1;
 609         }
 610         if( !*dynstrtab ) {
 611                 SysDebug("ERRO - No DT_STRTAB in %p", Base);
 612                 return 1;
 613         }
 614
 615         // ... ok... maybe they haven't been relocated
 616         if( (uintptr_t)*symtab < (uintptr_t)Base )
 617         {
 618                 SysDebug("Executable not yet relocated (symtab,pBuckets,dynstrtab = %p,%p,%p + 0x%x)",
 619                         *symtab,*pBuckets,*dynstrtab, iBaseDiff);
 620                 *symtab    = (void*)( (uintptr_t)*symtab    + iBaseDiff );
 621                 *pBuckets  = (void*)( (uintptr_t)*pBuckets  + iBaseDiff );
 622                 *dynstrtab = (void*)( (uintptr_t)*dynstrtab + iBaseDiff );
 623         }
 624         *piBaseDiff = iBaseDiff;
 625         return 0;
 626 }
 627
 628 int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type)
 629 {
 630         // Locate the tables
 631         uintptr_t       iBaseDiff = -1;
 632         Elf32_Sym       *symtab = NULL;
 633         Elf32_Word      *pBuckets = NULL;
 634         const char      *dynstrtab = NULL;
 635         if( Elf32GetSymbolVars(Base, &symtab, &pBuckets, &dynstrtab, &iBaseDiff) )
 636                 return 1;
 637
 638         int nbuckets = pBuckets[0];
 639 //      int iSymCount = pBuckets[1];
 640         pBuckets = &pBuckets[2];
 641         Elf32_Word* pChains = &pBuckets[ nbuckets ];
 642         assert(pChains);
 643
 644         // Get hash
 645         int iNameHash = ElfHashString(Name);
 646         iNameHash %= nbuckets;
 647
 648         // Walk Chain
 649         int idx = pBuckets[ iNameHash ];
 650         do {
 651                 const Elf32_Sym *sym = &symtab[idx];
 652                 assert(sym);
 653                 if( strcmp(dynstrtab + sym->st_name, Name) == 0 )
 654                 {
 655                         TRACE("*sym = {value:0x%x,size:0x%x,info:0x%x,other:0x%x,shndx:%i}",
 656                                 sym->st_value, sym->st_size, sym->st_info,
 657                                 sym->st_other, sym->st_shndx);
 658                         if(Addr)        *Addr = (void*)( sym->st_value );
 659                         if(Size)        *Size = sym->st_size;
 660                         if(Binding)     *Binding = ELF32_ST_BIND(sym->st_info);
 661                         if(Type)        *Type = ELF32_ST_TYPE(sym->st_info);
 662                         if(Section)     *Section = sym->st_shndx;
 663                         return 0;
 664                 }
 665         } while( (idx = pChains[idx]) != STN_UNDEF && idx != pBuckets[iNameHash] );
 666
 667         TRACE("No symbol");
 668         return 1;
 669 }
 670
 671 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
 672 {
 673          int    section;
 674         TRACE("Elf32GetSymbol(%p,%s,...)", Base, Name);
 675         if( Elf32GetSymbolInfo(Base, Name, ret, Size, &section, NULL, NULL) )
 676                 return 0;
 677         if( section == SHN_UNDEF ) {
 678                 TRACE("Elf32GetSymbol: Undefined", *ret, (Size?*Size:0), section);
 679                 return 0;
 680         }
 681         TRACE("Elf32GetSymbol: Found %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
 682         return 1;
 683 }
 684
 685 #ifdef SUPPORT_ELF64
 686 typedef int (*t_elf64_doreloc)(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
 687
 688 int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
 689 {
 690          int    sym = ELF64_R_SYM(r_info);
 691          int    type = ELF64_R_TYPE(r_info);
 692         const char      *symname = strtab + symtab[sym].st_name;
 693         void    *symval;
 694         //DEBUGS("_Elf64DoReloc: %s", symname);
 695         switch( type )
 696         {
 697         case R_X86_64_NONE:
 698                 break;
 699         case R_X86_64_64:
 700                 if( !GetSymbol(symname, &symval, NULL, NULL)  ) return 1;
 701                 *(uint64_t*)ptr = (uintptr_t)symval + addend;
 702                 break;
 703         case R_X86_64_COPY: {
 704                 size_t  size;
 705                 if( !GetSymbol(symname, &symval, &size, NULL)  )        return 1;
 706                 memcpy(ptr, symval, size);
 707                 } break;
 708         case R_X86_64_GLOB_DAT:
 709                 if( !GetSymbol(symname, &symval, NULL, NULL)  ) return 1;
 710                 *(uint64_t*)ptr = (uintptr_t)symval;
 711                 break;
 712         case R_X86_64_JUMP_SLOT:
 713                 if( !GetSymbol(symname, &symval, NULL, NULL)  ) return 1;
 714                 *(uint64_t*)ptr = (uintptr_t)symval;
 715                 break;
 716         case R_X86_64_RELATIVE:
 717                 *(uint64_t*)ptr = (uintptr_t)Base + addend;
 718                 break;
 719         default:
 720                 SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
 721                 return 2;
 722         }
 723         //DEBUGS("_Elf64DoReloc: - Good");
 724         return 0;
 725 }
 726
 727 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
 728 {
 729          int    i;
 730         Elf64_Ehdr      *hdr = Base;
 731         Elf64_Phdr      *phtab;
 732         Elf64_Dyn       *dyntab = NULL;
 733         Elf64_Addr      compiledBase = -1, baseDiff;
 734         Elf64_Sym       *symtab = NULL;
 735         char    *strtab = NULL;
 736         Elf64_Word      *hashtab = NULL;
 737         Elf64_Rel       *rel = NULL;
 738          int    rel_count = 0;
 739         Elf64_Rela      *rela = NULL;
 740          int    rela_count = 0;
 741         void    *pltrel = NULL;
 742          int    plt_size = 0, plt_type = 0;
 743
 744         TRACE("hdr = {");
 745         TRACE(" e_ident = '%.16s'", hdr->e_ident);
 746         TRACE(" e_type = 0x%x", hdr->e_type);
 747         TRACE(" e_machine = 0x%x", hdr->e_machine);
 748         TRACE(" e_version = 0x%x", hdr->e_version);
 749         TRACE(" e_entry = %p", hdr->e_entry);
 750         TRACE(" e_phoff = 0x%llx", hdr->e_phoff);
 751         TRACE(" e_shoff = 0x%llx", hdr->e_shoff);
 752         TRACE(" e_flags = 0x%x", hdr->e_flags);
 753         TRACE(" e_ehsize = 0x%x", hdr->e_ehsize);
 754         TRACE(" e_phentsize = 0x%x", hdr->e_phentsize);
 755         TRACE(" e_phnum = %i", hdr->e_phnum);
 756
 757         // Scan for the dynamic table (and find the compiled base)
 758         phtab = (void*)((uintptr_t)Base + (uintptr_t)hdr->e_phoff);
 759         for( i = 0; i < hdr->e_phnum; i ++ )
 760         {
 761                 if(phtab[i].p_type == PT_DYNAMIC)
 762                         dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
 763                 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
 764                         compiledBase = phtab[i].p_vaddr;
 765         }
 766
 767         baseDiff = (uintptr_t)Base - compiledBase;
 768
 769         TRACE("baseDiff = %p", baseDiff);
 770
 771         if(dyntab == NULL) {
 772                 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
 773                 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 774         }
 775
 776         dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
 777
 778         // Parse the dynamic table (first pass)
 779         // - Search for String, Symbol and Hash tables
 780         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 781         {
 782                 switch(dyntab[i].d_tag)
 783                 {
 784                 case DT_SYMTAB:
 785                         dyntab[i].d_un.d_ptr += baseDiff;
 786                         symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 787                         break;
 788                 case DT_STRTAB:
 789                         dyntab[i].d_un.d_ptr += baseDiff;
 790                         strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 791                         break;
 792                 case DT_HASH:
 793                         dyntab[i].d_un.d_ptr += baseDiff;
 794                         hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 795                         break;
 796                 }
 797         }
 798
 799         if( !symtab || !strtab || !hashtab ) {
 800                 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
 801                 return NULL;
 802         }
 803
 804         // Ready for symbol use
 805         AddLoaded( Filename, Base );
 806
 807         // Second pass on dynamic table
 808         for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
 809         {
 810                 TRACE("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
 811                 switch(dyntab[i].d_tag)
 812                 {
 813                 case DT_SONAME: break;
 814
 815                 case DT_NEEDED: {
 816                         char *libPath = strtab + dyntab[i].d_un.d_val;
 817                         TRACE("Elf64Relocate: libPath = '%s'", libPath);
 818                         if(LoadLibrary(libPath, NULL, envp) == 0) {
 819                                 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
 820                                 return NULL;
 821                         }
 822                         } break;
 823
 824                 // Relocation entries
 825                 case DT_REL:
 826                         dyntab[i].d_un.d_ptr += baseDiff;
 827                         rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 828                         break;
 829                 case DT_RELSZ:
 830                         rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
 831                         break;
 832                 case DT_RELENT:
 833                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
 834                                 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
 835                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
 836                                 return NULL;
 837                         }
 838                         break;
 839                 case DT_RELA:
 840                         dyntab[i].d_un.d_ptr += baseDiff;
 841                         rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 842                         break;
 843                 case DT_RELASZ:
 844                         rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
 845                         break;
 846                 case DT_RELAENT:
 847                         if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
 848                                 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
 849                                         dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
 850                                 return NULL;
 851                         }
 852                         break;
 853                 case DT_JMPREL:
 854                         dyntab[i].d_un.d_ptr += baseDiff;
 855                         pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
 856                         break;
 857                 case DT_PLTREL:
 858                         plt_type = dyntab[i].d_un.d_val;
 859                         break;
 860                 case DT_PLTRELSZ:
 861                         plt_size = dyntab[i].d_un.d_val;
 862                         break;
 863                 }
 864         }
 865
 866         // TODO: Relocate symbols
 867
 868         // Relocation function
 869         t_elf64_doreloc fpElf64DoReloc = &_Elf64DoReloc_X86_64;
 870         #define _Elf64DoReloc(info, ptr, addend)        fpElf64DoReloc(Base, strtab, symtab, info, ptr, addend)
 871
 872         int fail = 0;
 873         if( rel )
 874         {
 875                 TRACE("rel_count = %i", rel_count);
 876                 for( i = 0; i < rel_count; i ++ )
 877                 {
 878                         uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
 879                         fail |= _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
 880                 }
 881         }
 882
 883         if( rela )
 884         {
 885                 TRACE("rela_count = %i", rela_count);
 886                 for( i = 0; i < rela_count; i ++ )
 887                 {
 888                         uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
 889                         fail |= _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
 890                 }
 891         }
 892
 893         if( pltrel && plt_type )
 894         {
 895                 if( plt_type == DT_REL ) {
 896                         Elf64_Rel       *plt = pltrel;
 897                          int    count = plt_size / sizeof(Elf64_Rel);
 898                         TRACE("plt rel count = %i", count);
 899                         for( i = 0; i < count; i ++ )
 900                         {
 901                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 902                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
 903                         }
 904                 }
 905                 else {
 906                         Elf64_Rela      *plt = pltrel;
 907                          int    count = plt_size / sizeof(Elf64_Rela);
 908                         TRACE("plt rela count = %i", count);
 909                         for( i = 0; i < count; i ++ )
 910                         {
 911                                 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
 912                                 fail |= _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
 913                         }
 914                 }
 915         }
 916
 917         if( fail ) {
 918                 TRACE("Failure");
 919                 return NULL;
 920         }
 921
 922         {
 923         void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
 924         TRACE("Relocations done, return %p", ret);
 925         return ret;
 926         }
 927 }
 928
 929 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
 930 {
 931         Elf64_Ehdr      *hdr = Base;
 932         Elf64_Sym       *symtab;
 933          int    nbuckets = 0;
 934 //       int    iSymCount = 0;
 935          int    i;
 936         Elf64_Word      *pBuckets;
 937         Elf64_Word      *pChains;
 938         uint32_t        iNameHash;
 939         const char      *dynstrtab;
 940         uintptr_t       iBaseDiff = -1;
 941
 942         dynstrtab = NULL;
 943         pBuckets = NULL;
 944         symtab = NULL;
 945
 946         // Catch the current executable
 947         if( !pBuckets )
 948         {
 949                 Elf64_Phdr      *phtab;
 950                 Elf64_Dyn       *dynTab = NULL;
 951                  int    j;
 952
 953                 // Locate the tables
 954                 phtab = (void*)( (intptr_t)Base + (uintptr_t)hdr->e_phoff );
 955                 for( i = 0; i < hdr->e_phnum; i ++ )
 956                 {
 957                         if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
 958                                 iBaseDiff = phtab[i].p_vaddr;
 959                         if( phtab[i].p_type == PT_DYNAMIC ) {
 960                                 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
 961                         }
 962                 }
 963                 if( !dynTab ) {
 964                         SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
 965                         return 0;
 966                 }
 967                 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
 968                 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
 969
 970                 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
 971                 {
 972                         switch(dynTab[j].d_tag)
 973                         {
 974                         // --- Symbol Table ---
 975                         case DT_SYMTAB:
 976                                 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val;        // Rebased in Relocate
 977                                 break;
 978                         case DT_STRTAB:
 979                                 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
 980                                 break;
 981                         // --- Hash Table --
 982                         case DT_HASH:
 983                                 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
 984                                 break;
 985                         }
 986                 }
 987         }
 988
 989         nbuckets = pBuckets[0];
 990 //      iSymCount = pBuckets[1];
 991         pBuckets = &pBuckets[2];
 992         pChains = &pBuckets[ nbuckets ];
 993
 994         // Get hash
 995         iNameHash = ElfHashString(Name);
 996         iNameHash %= nbuckets;
 997
 998         // Walk Chain
 999         i = pBuckets[ iNameHash ];
1000         if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
1001                 *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
1002                 if(Size)        *Size = symtab[i].st_size;
1003                 TRACE("%s = %p", Name, *Ret);
1004                 return 1;
1005         }
1006
1007         while(pChains[i] != STN_UNDEF)
1008         {
1009                 i = pChains[i];
1010                 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
1011                         *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
1012                         if(Size)        *Size = symtab[i].st_size;
1013                         TRACE("%s = %p", Name, *Ret);
1014                         return 1;
1015                 }
1016         }
1017
1018         return 0;
1019 }
1020 #endif
1021
1022 uint32_t ElfHashString(const char *name)
1023 {
1024         uint32_t        h = 0, g;
1025         while(*name)
1026         {
1027                 h = (h << 4) + *(uint8_t*)name++;
1028                 if( (g = h & 0xf0000000) )
1029                         h ^= g >> 24;
1030                 h &= ~g;
1031         }
1032         return h;
1033 }
1034