-/*\r
- * AcessOS 1 - Dynamic Loader\r
- * By thePowersGang\r
- */\r
-#include "common.h"\r
-#include "elf32.h"\r
-
-#define DEBUG 0
-
-#if DEBUG\r
-# define DEBUGS(v...) SysDebug(v)\r
-#else
-# define DEBUGS(...)
-#endif
-\r
-// === CONSTANTS ===
-#if DEBUG\r
-//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"};\r
-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"};
-#endif\r
-\r
-// === PROTOTYPES ===\r
-void elf_doRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab, Uint base);\r
-Uint ElfHashString(char *name);\r
-\r
-// === CODE ===\r
-/**\r
- \fn int ElfRelocate(void *Base, char **envp, char *Filename)\r
- \brief Relocates a loaded ELF Executable\r
-*/\r
-int ElfRelocate(void *Base, char **envp, char *Filename)\r
-{\r
- Elf32_Ehdr *hdr = Base;\r
- Elf32_Phdr *phtab;\r
- int i, j; // Counters\r
- char *libPath;\r
- Uint iRealBase = -1;\r
- Uint iBaseDiff;\r
- int iSegmentCount;\r
- int iSymCount;\r
- Elf32_Rel *rel = NULL;\r
- Elf32_Rela *rela = NULL;\r
- Uint32 *pltgot = NULL;\r
- void *plt = NULL;\r
- int relSz=0, relEntSz=8;\r
- int relaSz=0, relaEntSz=8;\r
- int pltSz=0, pltType=0;\r
- Elf32_Dyn *dynamicTab = NULL; // Dynamic Table Pointer\r
- char *dynstrtab = NULL; // .dynamic String Table\r
- Elf32_Sym *dynsymtab;\r
- \r
- DEBUGS("ElfRelocate: (Base=0x%x)\n", Base);\r
- \r
- // Check magic header\r
- \r
- \r
- // Parse Program Header to get Dynamic Table\r
- phtab = Base + hdr->phoff;\r
- iSegmentCount = hdr->phentcount;\r
- for(i=0;i<iSegmentCount;i++)\r
- {\r
- // Determine linked base address\r
- if(phtab[i].Type == PT_LOAD && iRealBase > phtab[i].VAddr)\r
- iRealBase = phtab[i].VAddr;\r
- \r
- // Find Dynamic Section\r
- if(phtab[i].Type == PT_DYNAMIC) {\r
- if(dynamicTab) {\r
- DEBUGS(" WARNING - elf_relocate: Multiple PT_DYNAMIC segments\n");\r
- continue;\r
- }\r
- dynamicTab = (void *) phtab[i].VAddr;\r
- j = i; // Save Dynamic Table ID\r
- }\r
- }\r
- \r
- // Page Align real base\r
- iRealBase &= ~0xFFF;\r
- DEBUGS(" elf_relocate: True Base = 0x%x, Compiled Base = 0x%x\n", Base, iRealBase);\r
- \r
- // Adjust "Real" Base\r
- iBaseDiff = (Uint)Base - iRealBase;\r
- \r
- hdr->entrypoint += iBaseDiff; // Adjust Entrypoint\r
- \r
- // Check if a PT_DYNAMIC segement was found\r
- if(!dynamicTab) {\r
- SysDebug(" elf_relocate: No PT_DYNAMIC segment in image, returning\n");\r
- return hdr->entrypoint;\r
- }\r
- \r
- // Adjust Dynamic Table\r
- dynamicTab = (void *) ((Uint)dynamicTab + iBaseDiff);\r
-
- // === Get Symbol table and String Table ===\r
- for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
- {
- switch(dynamicTab[j].d_tag)
- {
- // --- Symbol Table ---\r
- case DT_SYMTAB:\r
- DEBUGS(" elf_relocate: DYNAMIC Symbol Table 0x%x (0x%x)\n",\r
- dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);\r
- dynamicTab[j].d_val += iBaseDiff;\r
- dynsymtab = (void*)(dynamicTab[j].d_val);\r
- hdr->misc.SymTable = dynamicTab[j].d_val; // Saved in unused bytes of ident\r
- break;\r
- // --- String Table ---\r
- case DT_STRTAB:\r
- DEBUGS(" elf_relocate: DYNAMIC String Table 0x%x (0x%x)\n",\r
- dynamicTab[j].d_val, dynamicTab[j].d_val + iBaseDiff);\r
- dynamicTab[j].d_val += iBaseDiff;\r
- dynstrtab = (void*)(dynamicTab[j].d_val);\r
- break;\r
- // --- Hash Table --\r
- case DT_HASH:\r
- dynamicTab[j].d_val += iBaseDiff;\r
- iSymCount = ((Uint*)(dynamicTab[j].d_val))[1];\r
- hdr->misc.HashTable = dynamicTab[j].d_val; // Saved in unused bytes of ident\r
- break;
- }
- }
-\r
- if(dynsymtab == NULL) {\r
- SysDebug("ld-acess.so - WARNING: No Dynamic Symbol table, returning\n");\r
- return hdr->entrypoint;\r
- }\r
- \r
- // Alter Symbols to true base\r
- for(i=0;i<iSymCount;i++)\r
- {\r
- dynsymtab[i].value += iBaseDiff;
- dynsymtab[i].nameOfs += (Uint)dynstrtab;\r
- //DEBUGS("elf_relocate: Sym '%s' = 0x%x (relocated)\n", dynsymtab[i].name, dynsymtab[i].value);\r
- }\r
-
- // === Add to loaded list (can be imported now) ===
- AddLoaded( Filename, (Uint)Base );
-
- // === Parse Relocation Data ===\r
- DEBUGS(" elf_relocate: dynamicTab = 0x%x\n", dynamicTab);\r
- for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
- {\r
- switch(dynamicTab[j].d_tag)\r
- {\r
- // --- Shared Library Name ---\r
- case DT_SONAME:\r
- DEBUGS(" elf_relocate: .so Name '%s'\n", dynstrtab+dynamicTab[j].d_val);\r
- break;\r
- // --- Needed Library ---\r
- case DT_NEEDED:\r
- libPath = dynstrtab + dynamicTab[j].d_val;\r
- DEBUGS(" Required Library '%s'\n", libPath);\r
- if(LoadLibrary(libPath, NULL, envp) == 0) {\r
- #if DEBUG\r
- DEBUGS(" elf_relocate: Unable to load '%s'\n", libPath);\r
- #else\r
- SysDebug("Unable to load required library '%s'\n", libPath);\r
- #endif\r
- return 0;\r
- }\r
- break;\r
- // --- PLT/GOT ---\r
- case DT_PLTGOT: pltgot = (void*)iBaseDiff+(dynamicTab[j].d_val); break;\r
- case DT_JMPREL: plt = (void*)(iBaseDiff+dynamicTab[j].d_val); break;\r
- case DT_PLTREL: pltType = dynamicTab[j].d_val; break;\r
- case DT_PLTRELSZ: pltSz = dynamicTab[j].d_val; break;\r
- \r
- // --- Relocation ---\r
- case DT_REL: rel = (void*)(iBaseDiff + dynamicTab[j].d_val); break;\r
- case DT_RELSZ: relSz = dynamicTab[j].d_val; break;\r
- case DT_RELENT: relEntSz = dynamicTab[j].d_val; break;\r
- case DT_RELA: rela = (void*)(iBaseDiff + dynamicTab[j].d_val); break;\r
- case DT_RELASZ: relaSz = dynamicTab[j].d_val; break;\r
- case DT_RELAENT: relaEntSz = dynamicTab[j].d_val; break;\r
- \r
- // --- Symbol Table ---\r
- case DT_SYMTAB:\r
- // --- Hash Table ---\r
- case DT_HASH:\r
- // --- String Table ---\r
- case DT_STRTAB:\r
- break;\r
- \r
- // --- Unknown ---\r
- default:\r
- if(dynamicTab[j].d_tag > DT_JMPREL) continue;\r
- //DEBUGS(" elf_relocate: %i-%i = %s,0x%x\n",\r
- // i,j, csaDT_NAMES[dynamicTab[j].d_tag],dynamicTab[j].d_val);\r
- break;\r
- }\r
- }\r
- \r
- DEBUGS(" elf_relocate: Beginning Relocation\n");\r
- \r
- // Parse Relocation Entries\r
- if(rel && relSz)\r
- {\r
- Uint32 *ptr;\r
- DEBUGS(" elf_relocate: rel=0x%x, relSz=0x%x, relEntSz=0x%x\n", rel, relSz, relEntSz);\r
- j = relSz / relEntSz;\r
- for( i = 0; i < j; i++ )\r
- {
- //DEBUGS(" Rel %i: 0x%x+0x%x\n", i, iBaseDiff, rel[i].r_offset);\r
- ptr = (void*)(iBaseDiff + rel[i].r_offset);\r
- elf_doRelocate(rel[i].r_info, ptr, *ptr, dynsymtab, iBaseDiff);\r
- }\r
- }\r
- // Parse Relocation Entries\r
- if(rela && relaSz)\r
- {\r
- Uint32 *ptr;\r
- DEBUGS(" elf_relocate: rela=0x%x, relaSz=0x%x, relaEntSz=0x%x\n", rela, relaSz, relaEntSz);\r
- j = relaSz / relaEntSz;\r
- for( i = 0; i < j; i++ )\r
- {\r
- ptr = (void*)(iBaseDiff + rela[i].r_offset);\r
- elf_doRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab, iBaseDiff);\r
- }\r
- }\r
- \r
- // === Process PLT (Procedure Linkage Table) ===\r
- if(plt && pltSz)\r
- {\r
- Uint32 *ptr;\r
- DEBUGS(" elf_relocate: Relocate PLT, plt=0x%x\n", plt);\r
- if(pltType == DT_REL)\r
- {\r
- Elf32_Rel *pltRel = plt;\r
- j = pltSz / sizeof(Elf32_Rel);\r
- DEBUGS(" elf_relocate: PLT Reloc Type = Rel, %i entries\n", j);\r
- for(i=0;i<j;i++)\r
- {\r
- ptr = (void*)(iBaseDiff + pltRel[i].r_offset);\r
- elf_doRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab, iRealBase);\r
- }\r
- }\r
- else\r
- {\r
- Elf32_Rela *pltRela = plt;\r
- j = pltSz / sizeof(Elf32_Rela);\r
- DEBUGS(" elf_relocate: PLT Reloc Type = Rela, %i entries\n", j);\r
- for(i=0;i<j;i++)\r
- {\r
- ptr = (void*)(iRealBase + pltRela[i].r_offset);\r
- elf_doRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab, iRealBase);\r
- }\r
- }\r
- }\r
- \r
- DEBUGS("ElfRelocate: RETURN 0x%x", hdr->entrypoint);\r
- return hdr->entrypoint;\r
-}\r
-\r
-void elf_doRelocate(Uint r_info, Uint32 *ptr, Uint32 addend, Elf32_Sym *symtab, Uint base)\r
-{\r
- int type = ELF32_R_TYPE(r_info);\r
- int sym = ELF32_R_SYM(r_info);\r
- Uint32 val;\r
- switch( type )\r
- {\r
- // Standard 32 Bit Relocation (S+A)\r
- case R_386_32:\r
- val = GetSymbol( symtab[sym].name );\r
- DEBUGS(" elf_doRelocate: R_386_32 *0x%x += 0x%x('%s')\n",\r
- ptr, val, symtab[sym].name);\r
- *ptr = val + addend;\r
- break;\r
- \r
- // 32 Bit Relocation wrt. Offset (S+A-P)\r
- case R_386_PC32:\r
- DEBUGS(" elf_doRelocate: #%i: '%s'\n", sym, symtab[sym].name);\r
- val = GetSymbol( symtab[sym].name );\r
- DEBUGS(" elf_doRelocate: R_386_PC32 *0x%x = 0x%x + 0x%x - 0x%x\n",\r
- ptr, *ptr, val, (Uint)ptr );\r
- *ptr = val + addend - (Uint)ptr;\r
- //*ptr = val + addend - ((Uint)ptr - base);\r
- break;
-\r
- // Absolute Value of a symbol (S)\r
- case R_386_GLOB_DAT:\r
- case R_386_JMP_SLOT:
- DEBUGS(" elf_doRelocate: #%i: '%s'\n", sym, symtab[sym].name);\r
- val = GetSymbol( symtab[sym].name );\r
- DEBUGS(" elf_doRelocate: %s *0x%x = 0x%x\n", csaR_NAMES[type], ptr, val);\r
- *ptr = val;\r
- break;\r
-\r
- // Base Address (B+A)\r
- case R_386_RELATIVE:\r
- DEBUGS(" elf_doRelocate: R_386_RELATIVE *0x%x = 0x%x + 0x%x\n", ptr, base, addend);\r
- *ptr = base + addend;\r
- break;\r
- \r
- default:\r
- DEBUGS(" elf_doRelocate: Rel 0x%x: 0x%x,%s\n", ptr, sym, csaR_NAMES[type]);\r
- break;\r
- }\r
- \r
-}
-\r
-/**\r
- * \fn int ElfGetSymbol(Uint Base, char *name, Uint *ret)\r
- */
-int ElfGetSymbol(Uint Base, char *Name, Uint *ret)
-{
- Elf32_Ehdr *hdr = (void*)Base;\r
- Elf32_Sym *symtab;
- int nbuckets = 0;\r
- int iSymCount = 0;
- int i;\r
- Uint *pBuckets;\r
- Uint *pChains;\r
- Uint iNameHash;
-\r
- //DEBUGS("ElfGetSymbol: (Base=0x%x, Name='%s')\n", Base, Name);\r
-\r
- pBuckets = (void *) hdr->misc.HashTable;\r
- symtab = (void *) hdr->misc.SymTable;\r
-
- nbuckets = pBuckets[0];\r
- iSymCount = pBuckets[1];\r
- pBuckets = &pBuckets[2];\r
- pChains = &pBuckets[ nbuckets ];\r
- \r
- // Get hash
- iNameHash = ElfHashString(Name);\r
- iNameHash %= nbuckets;\r
- //DEBUGS(" ElfGetSymbol: iNameHash = 0x%x\n", iNameHash);\r
-
- // Walk Chain\r
- i = pBuckets[ iNameHash ];\r
- //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")\n", symtab[i].name);\r
- if(symtab[i].shndx != SHN_UNDEF && strcmp(symtab[i].name, Name) == 0) {\r
- *ret = symtab[ i ].value;\r
- return 1;\r
- }\r
- \r
- //DEBUGS(" ElfGetSymbol: Hash of first = 0x%x\n", ElfHashString( symtab[i].name ) % nbuckets);\r
- while(pChains[i] != STN_UNDEF)\r
- {\r
- //DEBUGS(" pChains[%i] = %i\n", i, pChains[i]);\r
- i = pChains[i];\r
- //DEBUGS(" ElfGetSymbol: strcmp(Name, \"%s\")\n", symtab[ i ].name);\r
- if(symtab[i].shndx != SHN_UNDEF && strcmp(symtab[ i ].name, Name) == 0) {\r
- //DEBUGS("ElfGetSymbol: RETURN 1, '%s' = 0x%x\n", symtab[ i ].name, symtab[ i ].value);\r
- *ret = symtab[ i ].value;\r
- return 1;\r
- }\r
- }\r
- \r
- //DEBUGS("ElfGetSymbol: RETURN 0, Symbol '%s' not found\n", Name);
- return 0;
-}\r
-\r
-Uint ElfHashString(char *name)\r
-{\r
- Uint h = 0, g;\r
- while(*name)\r
- {\r
- h = (h << 4) + *name++;\r
- if( (g = h & 0xf0000000) )\r
- h ^= g >> 24;\r
- h &= ~g;\r
- }\r
- return h;\r
-}\r
-\r
-#if 0\r
-unsigned long elf_hash(const unsigned char *name)\r
-{\r
- unsigned long h = 0, g;\r
- while (*name)\r
- {\r
- h = (h << 4) + *name++;\r
- if (g = h & 0xf0000000)\r
- h ^= g >> 24;\r
- h &= ~g;\r
- }\r
- return h;\r
-}\r
-#endif\r