--- /dev/null
+/*\r
+ * Acess v0.1\r
+ * ELF Executable Loader Code\r
+ */\r
+#define DEBUG 0\r
+#include <stdlib.h>\r
+#include <stdio.h>\r
+#include <string.h>\r
+#include <unistd.h>\r
+#include "common.h"\r
+#include "elf.h"\r
+\r
+#define DEBUG_WARN 1\r
+\r
+#define MKPTR(_type,_val) ((_type*)(uintptr_t)(_val))\r
+#define PTRMK(_type,_val) MKPTR(_type,_val)\r
+#define PTR(_val) ((void*)(uintptr_t)(_val))\r
+\r
+#if DEBUG\r
+# define ENTER(...)\r
+# define LOG(s, ...) printf("%s: " s, __func__, __VA_ARGS__)\r
+# define LOGS(s) printf("%s: " s, __func__)\r
+# define LEAVE(...)\r
+#else\r
+# define ENTER(...)\r
+# define LOG(...)\r
+# define LOGS(...)\r
+# define LEAVE(...)\r
+#endif\r
+\r
+// === PROTOTYPES ===\r
+void *Elf_Load(FILE *FP);\r
+uintptr_t Elf_Relocate(void *Base);\r
+ int Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret);\r
+ int Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *Base);\r
+uint32_t Elf_Int_HashString(char *str);\r
+\r
+// === CODE ===\r
+void *Elf_Load(FILE *FP)\r
+{\r
+ Elf32_Ehdr hdr;\r
+ Elf32_Phdr *phtab;\r
+ int i, j;\r
+ int iPageCount;\r
+ uint32_t max, base = -1;\r
+ uint32_t addr;\r
+ uint32_t baseDiff = 0;\r
+ \r
+ ENTER("pFP", FP);\r
+ \r
+ // Read ELF Header\r
+ fread(&hdr, sizeof(hdr), 1, FP);\r
+ \r
+ // Check the file type\r
+ if(hdr.ident[0] != 0x7F || hdr.ident[1] != 'E' || hdr.ident[2] != 'L' || hdr.ident[3] != 'F') {\r
+ Warning("Non-ELF File was passed to the ELF loader\n");\r
+ LEAVE('n');\r
+ return NULL;\r
+ }\r
+ \r
+ // Check for a program header\r
+ if(hdr.phoff == 0) {\r
+ #if DEBUG_WARN\r
+ Warning("ELF File does not contain a program header\n");\r
+ #endif\r
+ LEAVE('n');\r
+ return NULL;\r
+ }\r
+ \r
+ // Read Program Header Table\r
+ phtab = malloc( sizeof(Elf32_Phdr) * hdr.phentcount );\r
+ if( !phtab ) {\r
+ LEAVE('n');\r
+ return NULL;\r
+ }\r
+ LOG("hdr.phoff = 0x%08x\n", hdr.phoff);\r
+ fseek(FP, hdr.phoff, SEEK_SET);\r
+ fread(phtab, sizeof(Elf32_Phdr), hdr.phentcount, FP);\r
+ \r
+ // Count Pages\r
+ iPageCount = 0;\r
+ LOG("hdr.phentcount = %i\n", hdr.phentcount);\r
+ for( i = 0; i < hdr.phentcount; i++ )\r
+ {\r
+ // Ignore Non-LOAD types\r
+ if(phtab[i].Type != PT_LOAD)\r
+ continue;\r
+ iPageCount += ((phtab[i].VAddr&0xFFF) + phtab[i].MemSize + 0xFFF) >> 12;\r
+ LOG("phtab[%i] = {VAddr:0x%x, MemSize:0x%x}\n", i, phtab[i].VAddr, phtab[i].MemSize);\r
+ }\r
+ \r
+ LOG("iPageCount = %i\n", iPageCount);\r
+ \r
+ // Allocate Information Structure\r
+ //ret = malloc( sizeof(tBinary) + sizeof(tBinaryPage)*iPageCount );\r
+ // Fill Info Struct\r
+ //ret->Entry = hdr.entrypoint;\r
+ //ret->Base = -1; // Set Base to maximum value\r
+ //ret->NumPages = iPageCount;\r
+ //ret->Interpreter = NULL;\r
+\r
+ // Prescan for base and size\r
+ for( i = 0; i < hdr.phentcount; i ++)\r
+ {\r
+ if( phtab[i].Type != PT_LOAD )\r
+ continue;\r
+ if( phtab[i].VAddr < base )\r
+ base = phtab[i].VAddr;\r
+ if( phtab[i].VAddr > max )\r
+ max = phtab[i].VAddr;\r
+ }\r
+\r
+ LOG("base = %08x, max = %08x\n", base, max);\r
+\r
+ if( base == 0 ) {\r
+ // Find a nice space (31 address bits allowed)\r
+ base = FindFreeRange( max, 31 );\r
+ LOG("new base = %08x\n", base);\r
+ if( base == 0 ) return NULL;\r
+ baseDiff = base;\r
+ }\r
+ \r
+ // Load Pages\r
+ j = 0;\r
+ for( i = 0; i < hdr.phentcount; i++ )\r
+ {\r
+ //LOG("phtab[%i].Type = 0x%x", i, phtab[i].Type);\r
+ LOG("phtab[%i] = {\n", i);\r
+ LOG(" .Type = 0x%08x\n", phtab[i].Type);\r
+ LOG(" .Offset = 0x%08x\n", phtab[i].Offset);\r
+ LOG(" .VAddr = 0x%08x\n", phtab[i].VAddr);\r
+ LOG(" .PAddr = 0x%08x\n", phtab[i].PAddr);\r
+ LOG(" .FileSize = 0x%08x\n", phtab[i].FileSize);\r
+ LOG(" .MemSize = 0x%08x\n", phtab[i].MemSize);\r
+ LOG(" .Flags = 0x%08x\n", phtab[i].Flags);\r
+ LOG(" .Align = 0x%08x\n", phtab[i].Align);\r
+ LOGS(" }\n");\r
+ // Get Interpreter Name\r
+ if( phtab[i].Type == PT_INTERP )\r
+ {\r
+ char *tmp;\r
+ //if(ret->Interpreter) continue;\r
+ tmp = malloc(phtab[i].FileSize);\r
+ fseek(FP, phtab[i].Offset, SEEK_SET);\r
+ fread(tmp, phtab[i].FileSize, 1, FP);\r
+ //ret->Interpreter = Binary_RegInterp(tmp);\r
+ LOG("Interpreter '%s'\n", tmp);\r
+ free(tmp);\r
+ continue;\r
+ }\r
+ // Ignore non-LOAD types\r
+ if(phtab[i].Type != PT_LOAD) continue;\r
+ \r
+ LOG("phtab[%i] = {VAddr:0x%x,Offset:0x%x,FileSize:0x%x}\n",\r
+ i, phtab[i].VAddr+baseDiff, phtab[i].Offset, phtab[i].FileSize);\r
+ \r
+ addr = phtab[i].VAddr + baseDiff;\r
+\r
+ if( AllocateMemory( addr, phtab[i].MemSize ) ) {\r
+ return NULL;\r
+ }\r
+ \r
+ fseek(FP, phtab[i].Offset, SEEK_SET);\r
+ fread( PTRMK(void, addr), phtab[i].FileSize, 1, FP );\r
+ memset( PTRMK(char, addr) + phtab[i].FileSize, 0, phtab[i].MemSize - phtab[i].FileSize );\r
+ }\r
+ \r
+ // Clean Up\r
+ free(phtab);\r
+ // Return\r
+ LEAVE('p', base);\r
+ return PTRMK(void, base);\r
+}\r
+\r
+// --- ELF RELOCATION ---\r
+/**\r
+ * \brief Relocates a loaded ELF Executable\r
+ */\r
+uintptr_t Elf_Relocate(void *Base)\r
+{\r
+ Elf32_Ehdr *hdr = Base;\r
+ Elf32_Phdr *phtab;\r
+ int i, j; // Counters\r
+ char *libPath;\r
+ uint32_t iRealBase = -1;\r
+ uintptr_t iBaseDiff;\r
+ int iSegmentCount;\r
+ int iSymCount = 0;\r
+ Elf32_Rel *rel = NULL;\r
+ Elf32_Rela *rela = NULL;\r
+ uint32_t *pltgot = NULL;\r
+ void *plt = NULL;\r
+ uint32_t *ptr;\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 = NULL;\r
+ int bFailed = 0;\r
+ \r
+ ENTER("pBase", Base);\r
+ LOG("Base = %p\n", Base);\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
+ Warning("Elf_Relocate - Multiple PT_DYNAMIC segments\n");\r
+ continue;\r
+ }\r
+ dynamicTab = MKPTR(void, phtab[i].VAddr);\r
+ j = i; // Save Dynamic Table ID\r
+ break;\r
+ }\r
+ }\r
+ \r
+ // Check if a PT_DYNAMIC segement was found\r
+ if(!dynamicTab) {\r
+ Warning("Elf_Relocate: No PT_DYNAMIC segment in image, returning\n");\r
+ LEAVE('x', hdr->entrypoint);\r
+ return hdr->entrypoint;\r
+ }\r
+ \r
+ // Page Align real base\r
+ iRealBase &= ~0xFFF;\r
+ \r
+ LOG("dynamicTab = %p\n", dynamicTab);\r
+ // Adjust "Real" Base\r
+ iBaseDiff = (uintptr_t)Base - iRealBase;\r
+ LOG("iBaseDiff = %p\n", (void*)iBaseDiff);\r
+ // Adjust Dynamic Table\r
+ dynamicTab = PTR( (uintptr_t)dynamicTab + iBaseDiff);\r
+ LOG("dynamicTab = %p\n", dynamicTab);\r
+\r
+ hdr->entrypoint += iBaseDiff;\r
+ \r
+ // === Get Symbol table and String Table ===\r
+ for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)\r
+ {\r
+ switch(dynamicTab[j].d_tag)\r
+ {\r
+ // --- Symbol Table ---\r
+ case DT_SYMTAB:\r
+ dynamicTab[j].d_val += iBaseDiff;\r
+ dynsymtab = PTRMK(void, dynamicTab[j].d_val);\r
+ hdr->misc.SymTable = dynamicTab[j].d_val; // Saved in unused bytes of ident\r
+ break;\r
+ \r
+ // --- String Table ---\r
+ case DT_STRTAB:\r
+ dynamicTab[j].d_val += iBaseDiff;\r
+ dynstrtab = PTRMK(void, dynamicTab[j].d_val);\r
+ break;\r
+ \r
+ // --- Hash Table --\r
+ case DT_HASH:\r
+ dynamicTab[j].d_val += iBaseDiff;\r
+ iSymCount = (PTRMK(uint32_t, dynamicTab[j].d_val))[1];\r
+ hdr->misc.HashTable = dynamicTab[j].d_val; // Saved in unused bytes of ident\r
+ break;\r
+ }\r
+ }\r
+\r
+\r
+ // Alter Symbols to true base\r
+ for(i = 0; i < iSymCount; i ++)\r
+ {\r
+ dynsymtab[i].nameOfs += (uintptr_t)dynstrtab;\r
+ if( dynsymtab[i].shndx == SHN_UNDEF )\r
+ {\r
+ LOG("Sym '%s' = UNDEF\n", MKPTR(char,dynsymtab[i].name));\r
+ }\r
+ else\r
+ {\r
+ dynsymtab[i].value += iBaseDiff;\r
+ LOG("Sym '%s' = 0x%x (relocated)\n", MKPTR(char,dynsymtab[i].name), dynsymtab[i].value);\r
+ }\r
+ }\r
+ \r
+ // === Add to loaded list (can be imported now) ===\r
+ Binary_SetReadyToUse( Base );\r
+\r
+ // === Parse Relocation Data ===\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
+ LOG(".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
+ Binary_LoadLibrary(libPath);\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
+ \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
+ }\r
+ \r
+ // Parse Relocation Entries\r
+ if(rel && relSz)\r
+ {\r
+ j = relSz / relEntSz;\r
+ for( i = 0; i < j; i++ )\r
+ {\r
+ ptr = (void*)(iBaseDiff + rel[i].r_offset);\r
+ if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
+ bFailed = 1;\r
+ }\r
+ }\r
+ }\r
+ // Parse Relocation Entries\r
+ if(rela && relaSz)\r
+ {\r
+ j = relaSz / relaEntSz;\r
+ for( i = 0; i < j; i++ )\r
+ {\r
+ ptr = (void*)(iBaseDiff + rela[i].r_offset);\r
+ if( !Elf_Int_DoRelocate(rel[i].r_info, ptr, rela[i].r_addend, dynsymtab, Base) ) {\r
+ bFailed = 1;\r
+ }\r
+ }\r
+ }\r
+ \r
+ // === Process PLT (Procedure Linkage Table) ===\r
+ if(plt && pltSz)\r
+ {\r
+ if(pltType == DT_REL)\r
+ {\r
+ Elf32_Rel *pltRel = plt;\r
+ j = pltSz / sizeof(Elf32_Rel);\r
+ LOG("PLT Rel - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
+ for(i = 0; i < j; i++)\r
+ {\r
+ ptr = (void*)(iBaseDiff + pltRel[i].r_offset);\r
+ if( !Elf_Int_DoRelocate(pltRel[i].r_info, ptr, *ptr, dynsymtab, Base) ) {\r
+ bFailed = 1;\r
+ }\r
+ }\r
+ }\r
+ else\r
+ {\r
+ Elf32_Rela *pltRela = plt;\r
+ j = pltSz / sizeof(Elf32_Rela);\r
+ LOG("PLT RelA - plt = %p, pltSz = %i (%i ents)\n", plt, pltSz, j);\r
+ for(i=0;i<j;i++)\r
+ {\r
+ ptr = (void*)(iBaseDiff + pltRela[i].r_offset);\r
+ if( !Elf_Int_DoRelocate(pltRela[i].r_info, ptr, pltRela[i].r_addend, dynsymtab, Base) ) {\r
+ bFailed = 1;\r
+ }\r
+ }\r
+ }\r
+ }\r
+ \r
+ if(bFailed) {\r
+ LEAVE('i', 0);\r
+ return 0;\r
+ }\r
+ \r
+ LEAVE('x', hdr->entrypoint);\r
+ return hdr->entrypoint;\r
+}\r
+\r
+/**\r
+ * \fn void Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
+ * \brief Performs a relocation\r
+ * \param r_info Field from relocation entry\r
+ * \param ptr Pointer to location of relocation\r
+ * \param addend Value to add to symbol\r
+ * \param symtab Symbol Table\r
+ * \param base Base of loaded binary\r
+ */\r
+int Elf_Int_DoRelocate(uint32_t r_info, uint32_t *ptr, uint32_t addend, Elf32_Sym *symtab, void *base)\r
+{\r
+ uintptr_t val;\r
+ int type = ELF32_R_TYPE(r_info);\r
+ int sym = ELF32_R_SYM(r_info);\r
+ char *sSymName = PTRMK(char, symtab[sym].name);\r
+ \r
+ //LogF("Elf_Int_DoRelocate: (r_info=0x%x, ptr=0x%x, addend=0x%x, .., base=0x%x)\n",\r
+ // r_info, ptr, addend, base);\r
+ \r
+ switch( type )\r
+ {\r
+ // Standard 32 Bit Relocation (S+A)\r
+ case R_386_32:\r
+ if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
+ Warning("Unable to find symbol '%s'", sSymName);\r
+ return 0;\r
+ }\r
+ LOG("%08x R_386_32 *%p += %p('%s')\n", r_info, ptr, (void*)val, sSymName);\r
+ *ptr = val + addend;\r
+ break;\r
+ \r
+ // 32 Bit Relocation wrt. Offset (S+A-P)\r
+ case R_386_PC32:\r
+ if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
+ Warning("Unable to find symbol '%s'", sSymName);\r
+ return 0;\r
+ }\r
+ LOG("%08x R_386_PC32 *%p = 0x%x + %p('%s') - %p\n", r_info, ptr, *ptr, (void*)val, sSymName, ptr );\r
+ // TODO: Check if it needs the true value of ptr or the compiled value\r
+ // NOTE: Testing using true value\r
+ *ptr = val + addend - (uintptr_t)ptr;\r
+ break;\r
+\r
+ // Absolute Value of a symbol (S)\r
+ case R_386_GLOB_DAT:\r
+ if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
+ Warning("Unable to find symbol '%s'", sSymName);\r
+ return 0; \r
+ }\r
+ LOG("%08x R_386_GLOB_DAT *%p = 0x%x(%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
+ *ptr = val;\r
+ break;\r
+ \r
+ // Absolute Value of a symbol (S)\r
+ case R_386_JMP_SLOT:\r
+ if( !Elf_GetSymbol( base, sSymName, &val ) && !Binary_GetSymbol( sSymName, &val ) ) {\r
+ Warning("Unable to find symbol '%s'", sSymName);\r
+ return 0;\r
+ }\r
+ LOG("%08x R_386_JMP_SLOT *%p = 0x%x (%s)\n", r_info, ptr, (unsigned int)val, sSymName);\r
+ *ptr = val;\r
+ break;\r
+\r
+ // Base Address (B+A)\r
+ case R_386_RELATIVE:\r
+ LOG("%08x R_386_RELATIVE *%p = %p + 0x%x\n", r_info, ptr, base, addend);\r
+ *ptr = (uintptr_t)base + addend;\r
+ break;\r
+ \r
+ default:\r
+ LOG("Rel %p: 0x%x,%i\n", ptr, sym, type);\r
+ break;\r
+ }\r
+ return 1;\r
+}\r
+\r
+/**\r
+ * \fn int Elf_GetSymbol(void *Base, char *name, uintptr_t *ret)\r
+ * \brief Get a symbol from the loaded binary\r
+ */\r
+int Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret)\r
+{\r
+ Elf32_Ehdr *hdr = (void*)Base;\r
+ Elf32_Sym *symtab;\r
+ int nbuckets = 0;\r
+ int iSymCount = 0;\r
+ int i;\r
+ uint32_t *pBuckets;\r
+ uint32_t *pChains;\r
+ uint32_t iNameHash;\r
+\r
+ if(!Base) return 0;\r
+\r
+ pBuckets = PTR(hdr->misc.HashTable);\r
+ symtab = PTR(hdr->misc.SymTable);\r
+ \r
+ nbuckets = pBuckets[0];\r
+ iSymCount = pBuckets[1];\r
+ pBuckets = &pBuckets[2];\r
+ pChains = &pBuckets[ nbuckets ];\r
+ \r
+ // Get hash\r
+ iNameHash = Elf_Int_HashString(Name);\r
+ iNameHash %= nbuckets;\r
+\r
+ // Check Bucket\r
+ i = pBuckets[ iNameHash ];\r
+ if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
+ if(ret) *ret = symtab[ i ].value;\r
+ return 1;\r
+ }\r
+ \r
+ // Walk Chain\r
+ while(pChains[i] != STN_UNDEF)\r
+ {\r
+ i = pChains[i];\r
+ if(symtab[i].shndx != SHN_UNDEF && strcmp(MKPTR(char,symtab[i].name), Name) == 0) {\r
+ if(ret) *ret = symtab[ i ].value;\r
+ return 1;\r
+ }\r
+ }\r
+ return 0;\r
+}\r
+\r
+/**\r
+ * \fn uint32_t Elf_Int_HashString(char *str)\r
+ * \brief Hash a string in the ELF format\r
+ * \param str String to hash\r
+ * \return Hash value\r
+ */\r
+uint32_t Elf_Int_HashString(char *str)\r
+{\r
+ uint32_t h = 0, g;\r
+ while(*str)\r
+ {\r
+ h = (h << 4) + *str++;\r
+ if( (g = h & 0xf0000000) )\r
+ h ^= g >> 24;\r
+ h &= ~g;\r
+ }\r
+ return h;\r
+}\r
git.ucc.asn.au / tpg / acess2.git / blobdiff
UCC git Repository :: git.ucc.asn.au