+/*\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
+ // 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("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