2 * Acess2 Dynamic Linker
3 * - By John Hodge (thePowersGang)
6 * - ELF32/ELF64 relocation
8 * TODO: Have GetSymbol() return a symbol "strength" on success. Allows STB_WEAK to be overriden by STB_GLOBAL
10 #ifndef KERNEL_VERSION
15 # define PAGE_SIZE 4096
27 # define DEBUG_OUT(...) SysDebug(__VA_ARGS__)
29 # define DEBUG_OUT(...) do{}while(0) //((void)(__VA_ARGS__))
32 #define WARNING(f,...) SysDebug("WARN: "f ,## __VA_ARGS__) // Malformed file
33 #define NOTICE(f,...) SysDebug("NOTICE: "f ,## __VA_ARGS__) // Missing relocation
34 //#define TRACE(f,...) DEBUG_OUT("TRACE:%s:%i "f, __func__, __LINE__ ,## __VA_ARGS__) // Debugging trace
35 #define TRACE(f,...) DEBUG_OUT("TRACE:%s "f, __func__,## __VA_ARGS__) // Debugging trace
38 # define SUPPORT_ELF64
49 typedef int tElf32RelocFcn(tElfRelocInfo *Info, uint32_t t_info, uint32_t *ptr, Elf32_Addr addend, int bRela);
53 //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"};
54 //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"};
58 void *ElfRelocate(void *Base, char **envp, const char *Filename);
59 int ElfGetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
60 void *Elf32Relocate(void *Base, char **envp, const char *Filename);
61 int Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff);
62 int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type);
63 int Elf32GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
64 tElf32RelocFcn elf_doRelocate_386;
65 tElf32RelocFcn elf_doRelocate_arm;
66 tElf32RelocFcn elf_doRelocate_unk;
68 int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
69 void *Elf64Relocate(void *Base, char **envp, const char *Filename);
70 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size);
72 int Elf32GetSymbolReloc(tElfRelocInfo *Info, const Elf32_Sym *Symbol, void **Ret, size_t *Size);
73 uint32_t ElfHashString(const char *name);
77 * \fn int ElfRelocate(void *Base, char **envp, const char *Filename)
78 * \brief Relocates a loaded ELF Executable
80 void *ElfRelocate(void *Base, char **envp, const char *Filename)
82 Elf32_Ehdr *hdr = Base;
84 switch(hdr->e_ident[4])
87 return Elf32Relocate(Base, envp, Filename);
90 return Elf64Relocate(Base, envp, Filename);
93 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
99 * \fn int ElfGetSymbol(Uint Base, const char *name, void **ret)
101 int ElfGetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
103 Elf32_Ehdr *hdr = Base;
105 switch(hdr->e_ident[4])
108 return Elf32GetSymbol(Base, Name, ret, Size);
111 return Elf64GetSymbol(Base, Name, ret, Size);
114 SysDebug("ld-acess - ElfRelocate: Unknown file class %i", hdr->e_ident[4]);
119 int elf_doRelocate_386(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
121 const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
122 void *symval = (void*)(intptr_t)sym->st_value;
123 size_t size = sym->st_size;
124 TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
125 switch( ELF32_R_TYPE(r_info) )
127 // Standard 32 Bit Relocation (S+A)
129 TRACE("R_386_32 *0x%x = %p + 0x%x", ptr, symval, addend);
130 *ptr = (intptr_t)symval + addend;
133 // 32 Bit Relocation wrt. Offset (S+A-P)
135 TRACE("R_386_PC32 *0x%x = 0x%x + 0x%p - 0x%x", ptr, *ptr, symval, (intptr_t)ptr );
136 *ptr = (intptr_t)symval + addend - (intptr_t)ptr;
137 //*ptr = val + addend - ((Uint)ptr - iBaseDiff);
140 // Absolute Value of a symbol (S)
142 TRACE("R_386_GLOB_DAT *0x%x = %p", ptr, symval); if(0)
144 TRACE("R_386_JMP_SLOT *0x%x = %p", ptr, symval);
145 *ptr = (intptr_t)symval;
148 // Base Address (B+A)
150 TRACE("R_386_RELATIVE *0x%x = 0x%x + 0x%x", ptr, Info->iBaseDiff, addend);
151 *ptr = Info->iBaseDiff + addend;
155 void *old_symval = symval;
156 GetSymbol(Info->strtab + sym->st_name, &symval, &size, Info->Base);
157 if( symval == old_symval )
159 if( ELF32_ST_BIND(sym->st_info) != STB_WEAK )
161 WARNING("sym={val:%p,size:0x%x,info:0x%x,other:0x%x,shndx:%i}",
162 sym->st_value, sym->st_size, sym->st_info, sym->st_other, sym->st_shndx);
163 WARNING("Can't find required external symbol '%s' for R_386_COPY", Info->strtab + sym->st_name);
166 // Don't bother doing the memcpy
167 TRACE("R_386_COPY (%p, %p, %i)", ptr, symval, size);
171 TRACE("R_386_COPY (%p, %p, %i)", ptr, symval, size);
172 memcpy(ptr, symval, size);
177 WARNING("Unknown relocation %i", ELF32_ST_TYPE(r_info));
183 int elf_doRelocate_arm(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
185 const Elf32_Sym *sym = &Info->symtab[ ELF32_R_SYM(r_info) ];
186 void *symval = (void*)(intptr_t)sym->st_value;
187 size_t size = sym->st_size;
188 TRACE("%i '%s'", ELF32_R_TYPE(r_info), Info->strtab + sym->st_name);
189 uintptr_t val = (uintptr_t)symval;
190 switch( ELF32_R_TYPE(r_info) )
194 TRACE("R_ARM_ABS32 %p (%p + %x)", ptr, symval, addend);
198 TRACE("R_ARM_GLOB_DAT %p (%p + %x)", ptr, symval, addend);
201 case R_ARM_JUMP_SLOT:
202 if(!bRela) addend = 0;
203 TRACE("R_ARM_JUMP_SLOT %p (%p + %x)", ptr, symval, addend);
208 TRACE("R_ARM_COPY (%p, %p, %i)", ptr, symval, size);
209 memcpy(ptr, symval, size);
211 // Delta between link and runtime locations + A
213 TRACE("R_ARM_RELATIVE %p (0x%x + 0x%x)", ptr, Info->iBaseDiff, addend);
214 if(ELF32_R_SYM(r_info) != 0) {
215 // TODO: Get delta for a symbol
216 WARNING("TODO - Implment R_ARM_RELATIVE for symbols");
220 *ptr = Info->iBaseDiff + addend;
224 WARNING("Unknown Relocation, %i", ELF32_R_TYPE(r_info));
230 int elf_doRelocate_unk(tElfRelocInfo *Info, uint32_t r_info, uint32_t *ptr, Elf32_Addr addend, int bRela)
235 void *Elf32Relocate(void *Base, char **envp, const char *Filename)
237 const Elf32_Ehdr *hdr = Base;
239 intptr_t iRealBase = -1;
240 Elf32_Rel *rel = NULL;
241 Elf32_Rela *rela = NULL;
243 int relSz=0, relEntSz=8;
244 int relaSz=0, relaEntSz=8;
245 int pltSz=0, pltType=0;
246 Elf32_Dyn *dynamicTab = NULL; // Dynamic Table Pointer
248 TRACE("(Base=0x%x)", Base);
250 // Check magic header
253 // Parse Program Header to get Dynamic Table
254 // - Determine the linked base of the executable
255 const Elf32_Phdr *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
256 const int iSegmentCount = hdr->phentcount;
257 for(int i = 0; i < iSegmentCount; i ++)
259 switch(phtab[i].Type)
262 // Determine linked base address
263 if( iRealBase > phtab[i].VAddr)
264 iRealBase = phtab[i].VAddr;
267 // Find Dynamic Section
269 dynamicTab = (void *) (intptr_t) phtab[i].VAddr;
272 WARNING("elf_relocate: Multiple PT_DYNAMIC segments");
278 // Page Align real base
281 // Adjust "Real" Base
282 const intptr_t iBaseDiff = (intptr_t)Base - iRealBase;
284 TRACE("True Base = 0x%x, Compiled Base = 0x%x, Difference = 0x%x", Base, iRealBase, iBaseDiff);
286 // Check if a PT_DYNAMIC segement was found
288 SysDebug(" elf_relocate: No PT_DYNAMIC segment in image %p, returning", Base);
289 return (void *)(intptr_t)(hdr->entrypoint + iBaseDiff);
292 // Allow writing to read-only segments, just in case they need to be relocated
293 // - Will be reversed at the end of the function
294 for( int i = 0; i < iSegmentCount; i ++ )
296 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
297 uintptr_t addr = phtab[i].VAddr + iBaseDiff;
298 uintptr_t end = addr + phtab[i].MemSize;
299 for( ; addr < end; addr += PAGE_SIZE )
300 _SysSetMemFlags(addr, 0, 1); // Unset RO
304 // Adjust Dynamic Table
305 dynamicTab = (void *)( (intptr_t)dynamicTab + iBaseDiff );
307 // === Get Symbol table and String Table ===
308 char *dynstrtab = NULL; // .dynamic String Table
309 Elf32_Sym *dynsymtab = NULL;
310 Elf32_Word *hashtable = NULL;
312 for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
314 const Elf32_Dyn *dt = &dynamicTab[j];
317 // --- Symbol Table ---
319 TRACE("DYNAMIC Symbol Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
320 dynsymtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
322 // --- String Table ---
324 TRACE("DYNAMIC String Table 0x%x (0x%x)", dt->d_val, dt->d_val + iBaseDiff);
325 dynstrtab = (void*)((intptr_t)dt->d_val + iBaseDiff);
329 TRACE("DYNAMIC Hash table %p (%p)", dt->d_val, dt->d_val + iBaseDiff);
330 hashtable = (void*)((intptr_t)dt->d_val + iBaseDiff);
331 iSymCount = hashtable[1];
336 if(dynsymtab == NULL) {
337 SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table in %p, returning", hdr);
338 return (void *)(intptr_t) (hdr->entrypoint + iBaseDiff);
341 // Apply base offset to locally defined symbols
342 // - #0 is defined as ("" SHN_UNDEF), so skip it
343 for( int i = 1; i < iSymCount; i ++ )
345 Elf32_Sym *sym = &dynsymtab[i];
346 const char *name = dynstrtab + sym->st_name;
348 if( sym->st_shndx == SHN_UNDEF )
350 TRACE("Sym %i'%s' deferred (SHN_UNDEF)", i, name);
352 else if( sym->st_shndx == SHN_ABS )
355 SysDebug("Sym %i'%s' untouched", i, name);
361 if( ELF32_ST_BIND(sym->st_info) != STB_WEAK )
363 TRACE("Sym %i'%s' = %p (local)", i, name, sym->st_value + iBaseDiff);
364 sym->st_value += iBaseDiff;
366 // If GetSymbol doesn't return a strong/global symbol value
367 else if( GetSymbol(name, &newval, &newsize, Base) != 1 )
369 TRACE("Sym %i'%s' = %p (Local weak)", i, name, sym->st_value + iBaseDiff);
370 sym->st_value += iBaseDiff;
374 TRACE("Sym %i'%s' = %p+0x%x (Extern weak)", i, name, newval, newsize);
375 sym->st_value = (uintptr_t)newval;
376 sym->st_size = newsize;
381 // === Add to loaded list (can be imported now) ===
382 AddLoaded( Filename, Base );
384 // === Parse Relocation Data ===
385 TRACE("dynamicTab = 0x%x", dynamicTab);
386 for( int j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
388 const Elf32_Dyn *dt = &dynamicTab[j];
391 // --- Shared Library Name ---
393 TRACE(".so Name '%s'", dynstrtab + dt->d_val);
395 // --- Needed Library ---
397 //assert(dt->d_val <= sizeof_dynstrtab);
398 libPath = dynstrtab + dt->d_val;
399 TRACE(" Required Library '%s'", libPath);
400 if(LoadLibrary(libPath, NULL, envp) == 0) {
401 SysDebug("Unable to load required library '%s'", libPath);
404 TRACE(" Lib loaded");
407 // case DT_PLTGOT: pltgot = (void*)(iBaseDiff + dt->d_val); break;
408 case DT_JMPREL: plt = (void*)(iBaseDiff + dt->d_val); break;
409 case DT_PLTREL: pltType = dt->d_val; break;
410 case DT_PLTRELSZ: pltSz = dt->d_val; break;
412 // --- Relocation ---
413 case DT_REL: rel = (void*)(iBaseDiff + dt->d_val); break;
414 case DT_RELSZ: relSz = dt->d_val; break;
415 case DT_RELENT: relEntSz = dt->d_val; break;
416 case DT_RELA: rela = (void*)(iBaseDiff + dt->d_val); break;
417 case DT_RELASZ: relaSz = dt->d_val; break;
418 case DT_RELAENT: relaEntSz = dt->d_val; break;
420 // --- Symbol Table ---
422 // --- Hash Table ---
424 // --- String Table ---
430 if(dt->d_tag > DT_JMPREL) continue;
431 //DEBUGS(" elf_relocate: %i-%i = %s,0x%x",
432 // i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);
437 // Resolve symbols (second pass)
438 // - #0 is defined as ("" SHN_UNDEF), so skip it
440 for( int i = 1; i < iSymCount; i ++ )
442 Elf32_Sym *sym = &dynsymtab[i];
443 const char *name = dynstrtab + sym->st_name;
444 if( sym->st_shndx == SHN_UNDEF )
448 if( !GetSymbol(name, &newval, &newsize, Base) ) {
449 if( ELF32_ST_BIND(sym->st_info) != STB_WEAK ) {
450 // Not a weak binding, set fail and move on
451 WARNING("Elf32Relocate: Can't find required symbol '%s' for '%s'",
456 // Leave the symbol value as-is
459 TRACE("Sym %i'%s' bound to %p+0x%x", i, name, newval, newsize);
460 sym->st_value = (intptr_t)newval;
461 sym->st_size = newsize;
464 else if( sym->st_shndx == SHN_ABS )
470 // Handled previously
471 // TODO: What about weak locally-defined symbols?
472 //assert( ELF32_ST_BIND(sym->st_info) != STB_WEAK );
476 WARNING("Relocation of '%s' failed", Filename);
480 TRACE("Beginning Relocation on '%s'", Filename);
483 tElf32RelocFcn *do_relocate;
487 do_relocate = elf_doRelocate_386;
490 do_relocate = elf_doRelocate_arm;
493 SysDebug("Elf32Relocate: Unknown machine type %i", hdr->machine);
494 do_relocate = elf_doRelocate_unk;
499 TRACE("do_relocate = %p (%p or %p)", do_relocate, &elf_doRelocate_386, &elf_doRelocate_arm);
501 #define _doRelocate(r_info, ptr, bRela, addend) \
502 do_relocate(&reloc_info, r_info, ptr, addend, bRela);
504 tElfRelocInfo reloc_info = {
506 .iBaseDiff = iBaseDiff,
511 // Parse Relocation Entries
515 TRACE("rel=0x%x, relSz=0x%x, relEntSz=0x%x", rel, relSz, relEntSz);
516 int max = relSz / relEntSz;
517 for( int i = 0; i < max; i++ )
519 ptr = (void*)(iBaseDiff + rel[i].r_offset);
520 fail |= _doRelocate(rel[i].r_info, ptr, 0, *ptr);
523 // Parse Relocation Entries
527 TRACE("rela=0x%x, relaSz=0x%x, relaEntSz=0x%x", rela, relaSz, relaEntSz);
528 int count = relaSz / relaEntSz;
529 for( int i = 0; i < count; i++ )
531 ptr = (void*)(iBaseDiff + rela[i].r_offset);
532 fail |= _doRelocate(rel[i].r_info, ptr, 1, rela[i].r_addend);
536 // === Process PLT (Procedure Linkage Table) ===
540 TRACE("Relocate PLT, plt=0x%x", plt);
541 if(pltType == DT_REL)
543 Elf32_Rel *pltRel = plt;
544 int count = pltSz / sizeof(Elf32_Rel);
545 TRACE("PLT Reloc Type = Rel, %i entries", count);
546 for(int i = 0; i < count; i ++)
548 ptr = (void*)(iBaseDiff + pltRel[i].r_offset);
549 fail |= _doRelocate(pltRel[i].r_info, ptr, 0, *ptr);
554 Elf32_Rela *pltRela = plt;
555 int count = pltSz / sizeof(Elf32_Rela);
556 TRACE("PLT Reloc Type = Rela, %i entries", count);
557 for(int i=0;i<count;i++)
559 ptr = (void*)(iRealBase + pltRela[i].r_offset);
560 fail |= _doRelocate(pltRela[i].r_info, ptr, 1, pltRela[i].r_addend);
566 for( int i = 0; i < iSegmentCount; i ++ )
568 // If load and not writable
569 if(phtab[i].Type == PT_LOAD && !(phtab[i].Flags & PF_W) ) {
570 uintptr_t addr = phtab[i].VAddr + iBaseDiff;
571 uintptr_t end = addr + phtab[i].MemSize;
572 for( ; addr < end; addr += PAGE_SIZE )
573 _SysSetMemFlags(addr, 1, 1); // Unset RO
578 TRACE("ElfRelocate: Failure");
584 TRACE("RETURN 0x%x to %p", hdr->entrypoint + iBaseDiff, __builtin_return_address(0));
585 return (void*)(intptr_t)( hdr->entrypoint + iBaseDiff );
588 int Elf32GetSymbolVars(void *Base, Elf32_Sym** symtab, Elf32_Word** pBuckets, const char **dynstrtab, uintptr_t* piBaseDiff)
590 Elf32_Dyn *dynTab = NULL;
591 uintptr_t iBaseDiff = -1;
592 Elf32_Ehdr *hdr = Base;
593 Elf32_Phdr *phtab = (void*)( (uintptr_t)Base + hdr->phoff );
594 for( int i = 0; i < hdr->phentcount; i ++ )
596 if(phtab[i].Type == PT_LOAD && iBaseDiff > phtab[i].VAddr)
597 iBaseDiff = phtab[i].VAddr;
598 if( phtab[i].Type == PT_DYNAMIC ) {
599 dynTab = (void*)(intptr_t)phtab[i].VAddr;
603 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
606 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
607 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
608 for( int i = 0; dynTab[i].d_tag != DT_NULL; i++)
610 switch(dynTab[i].d_tag)
612 // --- Symbol Table ---
614 *symtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff); // Rebased in Relocate
617 *dynstrtab = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
621 *pBuckets = (void*)((intptr_t)dynTab[i].d_val + iBaseDiff);
627 SysDebug("ERRO - No DT_SYMTAB in %p", Base);
631 SysDebug("ERRO - No DT_HASH in %p", Base);
635 SysDebug("ERRO - No DT_STRTAB in %p", Base);
639 // ... ok... maybe they haven't been relocated
640 if( (uintptr_t)*symtab < (uintptr_t)Base )
642 SysDebug("Executable not yet relocated (symtab,pBuckets,dynstrtab = %p,%p,%p + 0x%x)",
643 *symtab,*pBuckets,*dynstrtab, iBaseDiff);
644 *symtab = (void*)( (uintptr_t)*symtab + iBaseDiff );
645 *pBuckets = (void*)( (uintptr_t)*pBuckets + iBaseDiff );
646 *dynstrtab = (void*)( (uintptr_t)*dynstrtab + iBaseDiff );
648 *piBaseDiff = iBaseDiff;
652 int Elf32GetSymbolInfo(void *Base, const char *Name, void **Addr, size_t *Size, int* Section, int *Binding, int *Type)
655 uintptr_t iBaseDiff = -1;
656 Elf32_Sym *symtab = NULL;
657 Elf32_Word *pBuckets = NULL;
658 const char *dynstrtab = NULL;
659 if( Elf32GetSymbolVars(Base, &symtab, &pBuckets, &dynstrtab, &iBaseDiff) )
662 int nbuckets = pBuckets[0];
663 // int iSymCount = pBuckets[1];
664 pBuckets = &pBuckets[2];
665 Elf32_Word* pChains = &pBuckets[ nbuckets ];
669 int iNameHash = ElfHashString(Name);
670 iNameHash %= nbuckets;
673 int idx = pBuckets[ iNameHash ];
675 const Elf32_Sym *sym = &symtab[idx];
677 if( strcmp(dynstrtab + sym->st_name, Name) == 0 )
679 TRACE("*sym = {value:0x%x,size:0x%x,info:0x%x,other:0x%x,shndx:%i}",
680 sym->st_value, sym->st_size, sym->st_info,
681 sym->st_other, sym->st_shndx);
682 if(Addr) *Addr = (void*)(intptr_t)( sym->st_value );
683 if(Size) *Size = sym->st_size;
684 if(Binding) *Binding = ELF32_ST_BIND(sym->st_info);
685 if(Type) *Type = ELF32_ST_TYPE(sym->st_info);
686 if(Section) *Section = sym->st_shndx;
689 } while( (idx = pChains[idx]) != STN_UNDEF && idx != pBuckets[iNameHash] );
695 int Elf32GetSymbol(void *Base, const char *Name, void **ret, size_t *Size)
697 int section, binding;
698 TRACE("Elf32GetSymbol(%p,%s,...)", Base, Name);
699 if( Elf32GetSymbolInfo(Base, Name, ret, Size, §ion, &binding, NULL) )
701 if( section == SHN_UNDEF ) {
702 TRACE("Elf32GetSymbol: Undefined %p", *ret, (Size?*Size:0), section);
705 if( binding == STB_WEAK ) {
706 TRACE("Elf32GetSymbol: Weak, return %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
709 TRACE("Elf32GetSymbol: Found %p+0x%x,section=%i", *ret, (Size?*Size:0), section);
714 typedef int (*t_elf64_doreloc)(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend);
716 int _Elf64DoReloc_X86_64(void *Base, const char *strtab, Elf64_Sym *symtab, Elf64_Xword r_info, void *ptr, Elf64_Sxword addend)
718 int sym = ELF64_R_SYM(r_info);
719 int type = ELF64_R_TYPE(r_info);
720 const char *symname = strtab + symtab[sym].st_name;
722 //DEBUGS("_Elf64DoReloc: %s", symname);
728 if( !GetSymbol(symname, &symval, NULL, NULL) ) return 1;
729 *(uint64_t*)ptr = (uintptr_t)symval + addend;
731 case R_X86_64_COPY: {
733 if( !GetSymbol(symname, &symval, &size, NULL) ) return 1;
734 memcpy(ptr, symval, size);
736 case R_X86_64_GLOB_DAT:
737 if( !GetSymbol(symname, &symval, NULL, NULL) ) return 1;
738 *(uint64_t*)ptr = (uintptr_t)symval;
740 case R_X86_64_JUMP_SLOT:
741 if( !GetSymbol(symname, &symval, NULL, NULL) ) return 1;
742 *(uint64_t*)ptr = (uintptr_t)symval;
744 case R_X86_64_RELATIVE:
745 *(uint64_t*)ptr = (uintptr_t)Base + addend;
748 SysDebug("ld-acess - _Elf64DoReloc: Unknown relocation type %i", type);
751 //DEBUGS("_Elf64DoReloc: - Good");
755 void *Elf64Relocate(void *Base, char **envp, const char *Filename)
758 Elf64_Ehdr *hdr = Base;
760 Elf64_Dyn *dyntab = NULL;
761 Elf64_Addr compiledBase = -1, baseDiff;
762 Elf64_Sym *symtab = NULL;
764 Elf64_Word *hashtab = NULL;
765 Elf64_Rel *rel = NULL;
767 Elf64_Rela *rela = NULL;
770 int plt_size = 0, plt_type = 0;
773 TRACE(" e_ident = '%.16s'", hdr->e_ident);
774 TRACE(" e_type = 0x%x", hdr->e_type);
775 TRACE(" e_machine = 0x%x", hdr->e_machine);
776 TRACE(" e_version = 0x%x", hdr->e_version);
777 TRACE(" e_entry = %p", hdr->e_entry);
778 TRACE(" e_phoff = 0x%llx", hdr->e_phoff);
779 TRACE(" e_shoff = 0x%llx", hdr->e_shoff);
780 TRACE(" e_flags = 0x%x", hdr->e_flags);
781 TRACE(" e_ehsize = 0x%x", hdr->e_ehsize);
782 TRACE(" e_phentsize = 0x%x", hdr->e_phentsize);
783 TRACE(" e_phnum = %i", hdr->e_phnum);
785 // Scan for the dynamic table (and find the compiled base)
786 phtab = (void*)((uintptr_t)Base + (uintptr_t)hdr->e_phoff);
787 for( i = 0; i < hdr->e_phnum; i ++ )
789 if(phtab[i].p_type == PT_DYNAMIC)
790 dyntab = (void *)(intptr_t)phtab[i].p_vaddr;
791 if(phtab[i].p_type == PT_LOAD && compiledBase > phtab[i].p_vaddr)
792 compiledBase = phtab[i].p_vaddr;
795 baseDiff = (uintptr_t)Base - compiledBase;
797 TRACE("baseDiff = %p", baseDiff);
800 SysDebug(" Elf64Relocate: No PT_DYNAMIC segment in image %p, returning", Base);
801 return (void *)(uintptr_t)(hdr->e_entry + baseDiff);
804 dyntab = (void *)(uintptr_t)((uintptr_t)dyntab + baseDiff);
806 // Parse the dynamic table (first pass)
807 // - Search for String, Symbol and Hash tables
808 for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
810 switch(dyntab[i].d_tag)
813 dyntab[i].d_un.d_ptr += baseDiff;
814 symtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
817 dyntab[i].d_un.d_ptr += baseDiff;
818 strtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
821 dyntab[i].d_un.d_ptr += baseDiff;
822 hashtab = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
827 if( !symtab || !strtab || !hashtab ) {
828 SysDebug("ld-acess - Elf64Relocate: Missing Symbol, string or hash table");
832 // Ready for symbol use
833 AddLoaded( Filename, Base );
835 // Second pass on dynamic table
836 for(i = 0; dyntab[i].d_tag != DT_NULL; i ++)
838 TRACE("dyntab[%i].d_tag = %i", i, dyntab[i].d_tag);
839 switch(dyntab[i].d_tag)
841 case DT_SONAME: break;
844 char *libPath = strtab + dyntab[i].d_un.d_val;
845 TRACE("Elf64Relocate: libPath = '%s'", libPath);
846 if(LoadLibrary(libPath, NULL, envp) == 0) {
847 SysDebug("ld-acess - Elf64Relocate: Unable to load '%s'", libPath);
852 // Relocation entries
854 dyntab[i].d_un.d_ptr += baseDiff;
855 rel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
858 rel_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rel);
861 if( dyntab[i].d_un.d_val != sizeof(Elf64_Rel) ) {
862 SysDebug("ld-acess - Elf64Relocate: DT_RELENT(%i) != sizeof(Elf64_Rel)(%i)",
863 dyntab[i].d_un.d_val, sizeof(Elf64_Rel));
868 dyntab[i].d_un.d_ptr += baseDiff;
869 rela = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
872 rela_count = dyntab[i].d_un.d_val / sizeof(Elf64_Rela);
875 if( dyntab[i].d_un.d_val != sizeof(Elf64_Rela) ) {
876 SysDebug("ld-acess - Elf64Relocate: DT_RELAENT(%i) != sizeof(Elf64_Rela)(%i)",
877 dyntab[i].d_un.d_val, sizeof(Elf64_Rela));
882 dyntab[i].d_un.d_ptr += baseDiff;
883 pltrel = (void *)(uintptr_t)dyntab[i].d_un.d_ptr;
886 plt_type = dyntab[i].d_un.d_val;
889 plt_size = dyntab[i].d_un.d_val;
894 // TODO: Relocate symbols
896 // Relocation function
897 t_elf64_doreloc fpElf64DoReloc = &_Elf64DoReloc_X86_64;
898 #define _Elf64DoReloc(info, ptr, addend) fpElf64DoReloc(Base, strtab, symtab, info, ptr, addend)
903 TRACE("rel_count = %i", rel_count);
904 for( i = 0; i < rel_count; i ++ )
906 uint64_t *ptr = (void *)(uintptr_t)( rel[i].r_offset + baseDiff );
907 fail |= _Elf64DoReloc( rel[i].r_info, ptr, *ptr);
913 TRACE("rela_count = %i", rela_count);
914 for( i = 0; i < rela_count; i ++ )
916 uint64_t *ptr = (void *)(uintptr_t)( rela[i].r_offset + baseDiff );
917 fail |= _Elf64DoReloc( rela[i].r_info, ptr, rela[i].r_addend );
921 if( pltrel && plt_type )
923 if( plt_type == DT_REL ) {
924 Elf64_Rel *plt = pltrel;
925 int count = plt_size / sizeof(Elf64_Rel);
926 TRACE("plt rel count = %i", count);
927 for( i = 0; i < count; i ++ )
929 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
930 fail |= _Elf64DoReloc( plt[i].r_info, ptr, *ptr);
934 Elf64_Rela *plt = pltrel;
935 int count = plt_size / sizeof(Elf64_Rela);
936 TRACE("plt rela count = %i", count);
937 for( i = 0; i < count; i ++ )
939 uint64_t *ptr = (void *)(uintptr_t)( plt[i].r_offset + baseDiff );
940 fail |= _Elf64DoReloc( plt[i].r_info, ptr, plt[i].r_addend);
951 void *ret = (void *)(uintptr_t)(hdr->e_entry + baseDiff);
952 TRACE("Relocations done, return %p", ret);
957 int Elf64GetSymbol(void *Base, const char *Name, void **Ret, size_t *Size)
959 Elf64_Ehdr *hdr = Base;
962 // int iSymCount = 0;
964 Elf64_Word *pBuckets;
967 const char *dynstrtab;
968 uintptr_t iBaseDiff = -1;
974 // Catch the current executable
978 Elf64_Dyn *dynTab = NULL;
982 phtab = (void*)( (intptr_t)Base + (uintptr_t)hdr->e_phoff );
983 for( i = 0; i < hdr->e_phnum; i ++ )
985 if(phtab[i].p_type == PT_LOAD && iBaseDiff > phtab[i].p_vaddr)
986 iBaseDiff = phtab[i].p_vaddr;
987 if( phtab[i].p_type == PT_DYNAMIC ) {
988 dynTab = (void*)(intptr_t)phtab[i].p_vaddr;
992 SysDebug("ERROR - Unable to find DYNAMIC segment in %p", Base);
995 iBaseDiff = (intptr_t)Base - iBaseDiff; // Make iBaseDiff actually the diff
996 dynTab = (void*)( (intptr_t)dynTab + iBaseDiff );
998 for( j = 0; dynTab[j].d_tag != DT_NULL; j++)
1000 switch(dynTab[j].d_tag)
1002 // --- Symbol Table ---
1004 symtab = (void*)(intptr_t) dynTab[j].d_un.d_val; // Rebased in Relocate
1007 dynstrtab = (void*)(intptr_t) dynTab[j].d_un.d_val;
1009 // --- Hash Table --
1011 pBuckets = (void*)(intptr_t) dynTab[j].d_un.d_val;
1017 nbuckets = pBuckets[0];
1018 // iSymCount = pBuckets[1];
1019 pBuckets = &pBuckets[2];
1020 pChains = &pBuckets[ nbuckets ];
1023 iNameHash = ElfHashString(Name);
1024 iNameHash %= nbuckets;
1027 i = pBuckets[ iNameHash ];
1028 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
1029 *Ret = (void*)( (intptr_t)symtab[i].st_value + iBaseDiff );
1030 if(Size) *Size = symtab[i].st_size;
1031 TRACE("%s = %p", Name, *Ret);
1035 while(pChains[i] != STN_UNDEF)
1038 if(symtab[i].st_shndx != SHN_UNDEF && strcmp(dynstrtab + symtab[i].st_name, Name) == 0) {
1039 *Ret = (void*)((intptr_t)symtab[i].st_value + iBaseDiff);
1040 if(Size) *Size = symtab[i].st_size;
1041 TRACE("%s = %p", Name, *Ret);
1050 uint32_t ElfHashString(const char *name)
1055 h = (h << 4) + *(uint8_t*)name++;
1056 if( (g = h & 0xf0000000) )