feat: revamp libraries to use ELF shared objects

kernel/src/Api/LibSyscall.hpp

@@ -23,11 +23,15 @@ namespace Montauk {
     // Library entry tracking
     struct LibEntry {
         char path[128];
-        uint64_t baseAddr;
+        uint64_t loadBias;
         uint32_t refcount;
         bool inUse;
     };
 
+    static uint64_t GetLibSlotBase(int libSlot) {
+        return Sched::LIB_BASE + (uint64_t(libSlot) * Sched::LIB_MAX_SIZE);
+    }
+
     // Per-process library table
     static LibEntry g_libTable[MaxProcesses][MaxLibsPerProcess];
 
@@ -37,7 +41,7 @@ namespace Montauk {
         for (int i = 0; i < MaxLibsPerProcess; i++) {
             g_libTable[slot][i].inUse = false;
             g_libTable[slot][i].refcount = 0;
-            g_libTable[slot][i].baseAddr = 0;
+            g_libTable[slot][i].loadBias = 0;
             g_libTable[slot][i].path[0] = '\0';
         }
     }
@@ -77,8 +81,8 @@ namespace Montauk {
         }
 
         // Load the library into the process's address space
-        uint64_t libBase = Sched::ElfLoadLib(path, proc->pml4Phys, libSlot);
+        uint64_t loadBias = Sched::ElfLoadLib(path, proc->pml4Phys, libSlot);
-        if (libBase == 0) {
+        if (loadBias == 0) {
             Kt::KernelLogStream(Kt::ERROR, "Lib") << "Failed to load library: " << path;
             return 0;
         }
@@ -86,10 +90,10 @@ namespace Montauk {
         // Store library info
         g_libTable[slot][libSlot].inUse = true;
         g_libTable[slot][libSlot].refcount = 1;
-        g_libTable[slot][libSlot].baseAddr = libBase;
+        g_libTable[slot][libSlot].loadBias = loadBias;
         Lib::strncpy(g_libTable[slot][libSlot].path, path, sizeof(LibEntry::path));
 
-        Kt::KernelLogStream(Kt::OK, "Lib") << "Loaded library: " << path << " at base " << kcp::hex << libBase << kcp::dec;
+        Kt::KernelLogStream(Kt::OK, "Lib") << "Loaded library: " << path << " with load bias " << kcp::hex << loadBias << kcp::dec;
 
         return (uint64_t)(libSlot + 1);  // Handle = slot + 1 (0 = invalid)
     }
@@ -108,7 +112,7 @@ namespace Montauk {
         g_libTable[slot][libSlot].refcount--;
         if (g_libTable[slot][libSlot].refcount == 0) {
             // Actually unload - free the pages
-            uint64_t libBase = g_libTable[slot][libSlot].baseAddr;
+            uint64_t libBase = GetLibSlotBase(libSlot);
             uint64_t libEnd = libBase + Sched::LIB_MAX_SIZE;
 
             auto* proc = Sched::GetCurrentProcessPtr();
@@ -124,7 +128,7 @@ namespace Montauk {
             }
 
             g_libTable[slot][libSlot].inUse = false;
-            g_libTable[slot][libSlot].baseAddr = 0;
+            g_libTable[slot][libSlot].loadBias = 0;
             g_libTable[slot][libSlot].path[0] = '\0';
         }
 
@@ -133,7 +137,7 @@ namespace Montauk {
 
     // Resolve a symbol in a loaded library.
     // handle = library handle from LoadLib
-    // symbolOffset = offset of the symbol from the library's base address
+    // symbolOffset = ELF symbol value from the library's symbol table
     // Returns the virtual address of the symbol, or 0 if not found.
     static uint64_t Sys_DLSym(uint64_t handle, uint64_t symbolOffset) {
         int slot = GetCurrentSlot();
@@ -144,11 +148,11 @@ namespace Montauk {
 
         if (!g_libTable[slot][libSlot].inUse) return 0;
 
-        uint64_t libBase = g_libTable[slot][libSlot].baseAddr;
+        uint64_t loadBias = g_libTable[slot][libSlot].loadBias;
-        return libBase + symbolOffset;
+        return loadBias + symbolOffset;
     }
 
-    // Get library base address (for userspace symbol resolution)
+    // Get library relocation base / load bias (for userspace symbol resolution)
     static uint64_t Sys_GetLibBase(uint64_t handle) {
         int slot = GetCurrentSlot();
         if (slot < 0) return 0;
@@ -158,7 +162,7 @@ namespace Montauk {
 
         if (!g_libTable[slot][libSlot].inUse) return 0;
 
-        return g_libTable[slot][libSlot].baseAddr;
+        return g_libTable[slot][libSlot].loadBias;
     }
 
     // Cleanup library table for a process slot
@@ -171,7 +175,7 @@ namespace Montauk {
         // Unmap all libraries for this process
         for (int i = 0; i < MaxLibsPerProcess; i++) {
             if (g_libTable[slot][i].inUse) {
-                uint64_t libBase = g_libTable[slot][i].baseAddr;
+                uint64_t libBase = GetLibSlotBase(i);
                 uint64_t libEnd = libBase + Sched::LIB_MAX_SIZE;
 
                 for (uint64_t va = libBase; va < libEnd; va += 0x1000) {
@@ -184,7 +188,7 @@ namespace Montauk {
 
                 g_libTable[slot][i].inUse = false;
                 g_libTable[slot][i].refcount = 0;
-                g_libTable[slot][i].baseAddr = 0;
+                g_libTable[slot][i].loadBias = 0;
             }
         }
     }

kernel/src/Sched/ElfLoader.cpp

@@ -16,6 +16,368 @@
 
 namespace Sched {
 
+    struct Elf64Dynamic {
+        int64_t d_tag;
+        union {
+            uint64_t d_val;
+            uint64_t d_ptr;
+        };
+    };
+
+    struct Elf64Rela {
+        uint64_t r_offset;
+        uint64_t r_info;
+        int64_t r_addend;
+    };
+
+    struct Elf64Sym {
+        uint32_t st_name;
+        uint8_t  st_info;
+        uint8_t  st_other;
+        uint16_t st_shndx;
+        uint64_t st_value;
+        uint64_t st_size;
+    };
+
+    struct DynamicInfo {
+        uint64_t hashVaddr = 0;
+        uint64_t symtabVaddr = 0;
+        uint64_t strtabVaddr = 0;
+        uint64_t strtabSize = 0;
+        uint64_t relaVaddr = 0;
+        uint64_t relaSize = 0;
+        uint64_t relaEnt = sizeof(Elf64Rela);
+        uint64_t jmprelVaddr = 0;
+        uint64_t pltrelSize = 0;
+        uint64_t pltRelType = 0;
+        uint64_t symEnt = sizeof(Elf64Sym);
+    };
+
+    static constexpr uint64_t DT_NULL     = 0;
+    static constexpr uint64_t DT_PLTRELSZ = 2;
+    static constexpr uint64_t DT_HASH     = 4;
+    static constexpr uint64_t DT_STRTAB   = 5;
+    static constexpr uint64_t DT_SYMTAB   = 6;
+    static constexpr uint64_t DT_RELA     = 7;
+    static constexpr uint64_t DT_RELASZ   = 8;
+    static constexpr uint64_t DT_RELAENT  = 9;
+    static constexpr uint64_t DT_STRSZ    = 10;
+    static constexpr uint64_t DT_SYMENT   = 11;
+    static constexpr uint64_t DT_PLTREL   = 20;
+    static constexpr uint64_t DT_JMPREL   = 23;
+
+    static constexpr uint32_t R_X86_64_64        = 1;
+    static constexpr uint32_t R_X86_64_GLOB_DAT  = 6;
+    static constexpr uint32_t R_X86_64_JUMP_SLOT = 7;
+    static constexpr uint32_t R_X86_64_RELATIVE  = 8;
+
+    static constexpr uint16_t SHN_UNDEF = 0;
+    static constexpr uint8_t STB_WEAK   = 2;
+
+    static constexpr uint32_t Elf64RelocType(uint64_t info) {
+        return static_cast<uint32_t>(info);
+    }
+
+    static constexpr uint32_t Elf64RelocSym(uint64_t info) {
+        return static_cast<uint32_t>(info >> 32);
+    }
+
+    static uint64_t AddSigned(uint64_t base, int64_t addend) {
+        if (addend >= 0) {
+            return base + static_cast<uint64_t>(addend);
+        }
+
+        return base - static_cast<uint64_t>(-addend);
+    }
+
+    static bool ValidateProgramHeaderTable(const Elf64Header* hdr, uint64_t fileSize) {
+        if (hdr->e_phentsize != sizeof(Elf64ProgramHeader)) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unexpected program header size";
+            return false;
+        }
+
+        if (hdr->e_phoff > fileSize ||
+            hdr->e_phoff + uint64_t(hdr->e_phnum) * hdr->e_phentsize > fileSize) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Program headers outside file";
+            return false;
+        }
+
+        return true;
+    }
+
+    static bool ValidateLoadSegment(const Elf64ProgramHeader* phdr, uint64_t fileSize) {
+        if (phdr->p_filesz > phdr->p_memsz) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Segment file size exceeds memory size";
+            return false;
+        }
+
+        if (phdr->p_offset > fileSize || phdr->p_offset + phdr->p_filesz > fileSize) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Segment outside file";
+            return false;
+        }
+
+        return true;
+    }
+
+    static bool ValidateLibElfHeader(const Elf64Header* hdr) {
+        if (hdr->e_ident[0] != 0x7f ||
+            hdr->e_ident[1] != 'E'  ||
+            hdr->e_ident[2] != 'L'  ||
+            hdr->e_ident[3] != 'F') {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Invalid ELF magic";
+            return false;
+        }
+
+        if (hdr->e_ident[4] != 2) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not a 64-bit ELF";
+            return false;
+        }
+
+        if (hdr->e_ident[5] != 1) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not little-endian";
+            return false;
+        }
+
+        if (hdr->e_type != ET_DYN) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Library is not ET_DYN (type=" << (uint64_t)hdr->e_type << ")";
+            return false;
+        }
+
+        if (hdr->e_machine != EM_X86_64) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not x86_64 (machine=" << (uint64_t)hdr->e_machine << ")";
+            return false;
+        }
+
+        return true;
+    }
+
+    static bool VirtToFileOffset(const Elf64Header* hdr, uint64_t fileSize,
+                                 uint64_t virtualAddress, uint64_t size, uint64_t* outOffset) {
+        for (uint16_t i = 0; i < hdr->e_phnum; i++) {
+            auto* phdr = (const Elf64ProgramHeader*)((const uint8_t*)hdr + hdr->e_phoff + i * hdr->e_phentsize);
+
+            if (phdr->p_type != PT_LOAD || phdr->p_filesz == 0) {
+                continue;
+            }
+
+            if (!ValidateLoadSegment(phdr, fileSize)) {
+                return false;
+            }
+
+            if (virtualAddress < phdr->p_vaddr) {
+                continue;
+            }
+
+            if (virtualAddress + size > phdr->p_vaddr + phdr->p_filesz) {
+                continue;
+            }
+
+            *outOffset = phdr->p_offset + (virtualAddress - phdr->p_vaddr);
+            return true;
+        }
+
+        Kt::KernelLogStream(Kt::ERROR, "ELF") << "Failed to translate virtual address " << kcp::hex
+                                              << virtualAddress << kcp::dec << " to file offset";
+        return false;
+    }
+
+    static bool WriteUser64(uint64_t pml4Phys, uint64_t virtualAddress, uint64_t value) {
+        uint64_t physBase = Memory::VMM::Paging::GetPhysAddr(pml4Phys, virtualAddress);
+        if (physBase == 0) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Relocation target not mapped";
+            return false;
+        }
+
+        uint64_t physAddress = physBase + (virtualAddress & 0xFFFULL);
+        *(uint64_t*)Memory::HHDM(physAddress) = value;
+        return true;
+    }
+
+    static bool ApplyRelaBlock(uint64_t pml4Phys, uint64_t loadBias,
+                               const Elf64Rela* relas, uint64_t relaCount,
+                               const Elf64Sym* dynsym, uint64_t dynsymCount,
+                               const char* dynstr, uint64_t dynstrSize) {
+        for (uint64_t i = 0; i < relaCount; i++) {
+            const Elf64Rela& rela = relas[i];
+            uint32_t type = Elf64RelocType(rela.r_info);
+            uint32_t symIndex = Elf64RelocSym(rela.r_info);
+            uint64_t targetVA = loadBias + rela.r_offset;
+            uint64_t value = 0;
+
+            switch (type) {
+                case 0:
+                    continue;
+
+                case R_X86_64_RELATIVE:
+                    value = AddSigned(loadBias, rela.r_addend);
+                    break;
+
+                case R_X86_64_GLOB_DAT:
+                case R_X86_64_JUMP_SLOT:
+                case R_X86_64_64: {
+                    if (symIndex >= dynsymCount) {
+                        Kt::KernelLogStream(Kt::ERROR, "ELF") << "Relocation symbol index out of range";
+                        return false;
+                    }
+
+                    const Elf64Sym& sym = dynsym[symIndex];
+                    if (sym.st_shndx == SHN_UNDEF) {
+                        uint8_t bind = sym.st_info >> 4;
+                        if (bind == STB_WEAK) {
+                            value = 0;
+                            break;
+                        }
+
+                        const char* name = "<unnamed>";
+                        if (dynstr != nullptr && sym.st_name < dynstrSize) {
+                            name = dynstr + sym.st_name;
+                        }
+                        Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unresolved dynamic symbol: " << name;
+                        return false;
+                    }
+
+                    value = AddSigned(loadBias + sym.st_value, rela.r_addend);
+                    break;
+                }
+
+                default:
+                    Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unsupported relocation type=" << (uint64_t)type;
+                    return false;
+            }
+
+            if (!WriteUser64(pml4Phys, targetVA, value)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    static bool ApplyDynamicRelocations(const uint8_t* fileData, uint64_t fileSize,
+                                        const Elf64Header* hdr, uint64_t pml4Phys,
+                                        uint64_t loadBias) {
+        const Elf64ProgramHeader* dynamicPhdr = nullptr;
+
+        for (uint16_t i = 0; i < hdr->e_phnum; i++) {
+            auto* phdr = (const Elf64ProgramHeader*)(fileData + hdr->e_phoff + i * hdr->e_phentsize);
+            if (phdr->p_type == PT_DYNAMIC) {
+                dynamicPhdr = phdr;
+                break;
+            }
+        }
+
+        if (dynamicPhdr == nullptr) {
+            return true;
+        }
+
+        if (dynamicPhdr->p_offset > fileSize || dynamicPhdr->p_offset + dynamicPhdr->p_filesz > fileSize) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Dynamic section outside file";
+            return false;
+        }
+
+        DynamicInfo info;
+        uint64_t dynCount = dynamicPhdr->p_filesz / sizeof(Elf64Dynamic);
+        auto* dyn = (const Elf64Dynamic*)(fileData + dynamicPhdr->p_offset);
+
+        for (uint64_t i = 0; i < dynCount; i++) {
+            if (dyn[i].d_tag == DT_NULL) {
+                break;
+            }
+
+            switch (dyn[i].d_tag) {
+                case DT_HASH:     info.hashVaddr = dyn[i].d_ptr; break;
+                case DT_SYMTAB:   info.symtabVaddr = dyn[i].d_ptr; break;
+                case DT_STRTAB:   info.strtabVaddr = dyn[i].d_ptr; break;
+                case DT_STRSZ:    info.strtabSize = dyn[i].d_val; break;
+                case DT_RELA:     info.relaVaddr = dyn[i].d_ptr; break;
+                case DT_RELASZ:   info.relaSize = dyn[i].d_val; break;
+                case DT_RELAENT:  info.relaEnt = dyn[i].d_val; break;
+                case DT_JMPREL:   info.jmprelVaddr = dyn[i].d_ptr; break;
+                case DT_PLTRELSZ: info.pltrelSize = dyn[i].d_val; break;
+                case DT_PLTREL:   info.pltRelType = dyn[i].d_val; break;
+                case DT_SYMENT:   info.symEnt = dyn[i].d_val; break;
+                default:
+                    break;
+            }
+        }
+
+        if (info.relaSize == 0 && info.pltrelSize == 0) {
+            return true;
+        }
+
+        if (info.symEnt != sizeof(Elf64Sym)) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unexpected dynamic symbol size";
+            return false;
+        }
+
+        if (info.relaEnt != sizeof(Elf64Rela)) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unexpected RELA entry size";
+            return false;
+        }
+
+        if (info.symtabVaddr == 0 || info.hashVaddr == 0) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Missing dynamic symbol metadata";
+            return false;
+        }
+
+        uint64_t hashOffset = 0;
+        if (!VirtToFileOffset(hdr, fileSize, info.hashVaddr, sizeof(uint32_t) * 2, &hashOffset)) {
+            return false;
+        }
+
+        auto* hashWords = (const uint32_t*)(fileData + hashOffset);
+        uint64_t dynsymCount = hashWords[1];
+
+        uint64_t dynsymOffset = 0;
+        if (!VirtToFileOffset(hdr, fileSize, info.symtabVaddr,
+                              dynsymCount * sizeof(Elf64Sym), &dynsymOffset)) {
+            return false;
+        }
+
+        auto* dynsym = (const Elf64Sym*)(fileData + dynsymOffset);
+        const char* dynstr = nullptr;
+        if (info.strtabVaddr != 0 && info.strtabSize != 0) {
+            uint64_t dynstrOffset = 0;
+            if (!VirtToFileOffset(hdr, fileSize, info.strtabVaddr, info.strtabSize, &dynstrOffset)) {
+                return false;
+            }
+            dynstr = (const char*)(fileData + dynstrOffset);
+        }
+
+        if (info.relaSize != 0) {
+            uint64_t relaOffset = 0;
+            if (!VirtToFileOffset(hdr, fileSize, info.relaVaddr, info.relaSize, &relaOffset)) {
+                return false;
+            }
+
+            auto* relas = (const Elf64Rela*)(fileData + relaOffset);
+            if (!ApplyRelaBlock(pml4Phys, loadBias, relas, info.relaSize / sizeof(Elf64Rela),
+                                dynsym, dynsymCount, dynstr, info.strtabSize)) {
+                return false;
+            }
+        }
+
+        if (info.pltrelSize != 0) {
+            if (info.pltRelType != DT_RELA) {
+                Kt::KernelLogStream(Kt::ERROR, "ELF") << "Unsupported PLT relocation format";
+                return false;
+            }
+
+            uint64_t jmprelOffset = 0;
+            if (!VirtToFileOffset(hdr, fileSize, info.jmprelVaddr, info.pltrelSize, &jmprelOffset)) {
+                return false;
+            }
+
+            auto* pltRelas = (const Elf64Rela*)(fileData + jmprelOffset);
+            if (!ApplyRelaBlock(pml4Phys, loadBias, pltRelas, info.pltrelSize / sizeof(Elf64Rela),
+                                dynsym, dynsymCount, dynstr, info.strtabSize)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     static bool ValidateElfHeader(const Elf64Header* hdr) {
         // Check ELF magic: 0x7f 'E' 'L' 'F'
         if (hdr->e_ident[0] != 0x7f ||
@@ -177,43 +539,48 @@ namespace Sched {
 
         Elf64Header* hdr = (Elf64Header*)fileData;
 
-        // Validate ELF header
+        if (!ValidateLibElfHeader(hdr) || !ValidateProgramHeaderTable(hdr, fileSize)) {
-        if (hdr->e_ident[0] != 0x7f ||
-            hdr->e_ident[1] != 'E'  ||
-            hdr->e_ident[2] != 'L'  ||
-            hdr->e_ident[3] != 'F') {
-            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Invalid ELF magic";
             Memory::g_heap->Free(fileData);
             return 0;
         }
 
-        if (hdr->e_ident[4] != 2) {
+        uint64_t slotBase = LIB_BASE + (uint64_t(slot) * LIB_MAX_SIZE);
-            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not a 64-bit ELF";
+        uint64_t minLoadStart = ~0ULL;
+        uint64_t maxLoadEnd = 0;
+        bool hasLoadSegment = false;
+
+        for (uint16_t i = 0; i < hdr->e_phnum; i++) {
+            auto* phdr = (Elf64ProgramHeader*)(fileData + hdr->e_phoff + i * hdr->e_phentsize);
+
+            if (phdr->p_type != PT_LOAD || phdr->p_memsz == 0) {
+                continue;
+            }
+
+            if (!ValidateLoadSegment(phdr, fileSize)) {
                 Memory::g_heap->Free(fileData);
                 return 0;
             }
 
-        if (hdr->e_ident[5] != 1) {
+            uint64_t segStart = phdr->p_vaddr & ~0xFFFULL;
-            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not little-endian";
+            uint64_t segEnd = (phdr->p_vaddr + phdr->p_memsz + 0xFFFULL) & ~0xFFFULL;
+            if (segStart < minLoadStart) minLoadStart = segStart;
+            if (segEnd > maxLoadEnd) maxLoadEnd = segEnd;
+            hasLoadSegment = true;
+        }
+
+        if (!hasLoadSegment) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Library has no loadable segments";
             Memory::g_heap->Free(fileData);
             return 0;
         }
 
-        // Libraries are built as ET_EXEC at a fixed base (0x60000000)
+        if (maxLoadEnd - minLoadStart > LIB_MAX_SIZE) {
-        if (hdr->e_type != ET_EXEC) {
+            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Library image exceeds slot size";
-            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Library not ET_EXEC (type=" << (uint64_t)hdr->e_type << ")";
             Memory::g_heap->Free(fileData);
             return 0;
         }
 
-        if (hdr->e_machine != EM_X86_64) {
+        uint64_t loadBias = slotBase - minLoadStart;
-            Kt::KernelLogStream(Kt::ERROR, "ELF") << "Not x86_64 (machine=" << (uint64_t)hdr->e_machine << ")";
-            Memory::g_heap->Free(fileData);
-            return 0;
-        }
-
-        // Calculate library base for this slot (each slot gets LIB_MAX_SIZE region)
-        uint64_t libBase = LIB_BASE + (uint64_t(slot) * LIB_MAX_SIZE);
 
         // Process program headers
         for (uint16_t i = 0; i < hdr->e_phnum; i++) {
@@ -227,9 +594,7 @@ namespace Sched {
                 continue;
             }
 
-            // The library is linked at 0x400000. We need to relocate it to libBase.
+            uint64_t targetSegStart = loadBias + phdr->p_vaddr;
-            // target_vaddr = libBase + (file_vaddr - 0x400000)
-            uint64_t targetSegStart = libBase + (phdr->p_vaddr - 0x400000ULL);
             uint64_t targetSegFileEnd = targetSegStart + phdr->p_filesz;  // only file data
             uint64_t targetSegMemEnd = targetSegStart + phdr->p_memsz;    // includes bss
 
@@ -251,7 +616,7 @@ namespace Sched {
                 uint64_t pageEnd = pageStart + 0x1000;
 
                 // Check that we're within the library region
-                if (pageStart < libBase || pageEnd > libBase + LIB_MAX_SIZE) {
+                if (pageStart < slotBase || pageEnd > slotBase + LIB_MAX_SIZE) {
                     Kt::KernelLogStream(Kt::ERROR, "ELF") << "Segment outside library region";
                     Memory::g_heap->Free(fileData);
                     return 0;
@@ -282,10 +647,14 @@ namespace Sched {
             }
         }
 
+        if (!ApplyDynamicRelocations(fileData, fileSize, hdr, pml4Phys, loadBias)) {
+            Memory::g_heap->Free(fileData);
+            return 0;
+        }
+
         Memory::g_heap->Free(fileData);
 
-        // Return the library base address for this slot
+        return loadBias;
-        return libBase;
     }
 
 }

kernel/src/Sched/ElfLoader.hpp

@@ -38,7 +38,9 @@ namespace Sched {
     };
 
     static constexpr uint32_t PT_LOAD    = 1;
+    static constexpr uint32_t PT_DYNAMIC = 2;
     static constexpr uint16_t ET_EXEC    = 2;
+    static constexpr uint16_t ET_DYN     = 3;
     static constexpr uint16_t EM_X86_64  = 62;
 
     // Fixed base address for shared libraries.
@@ -51,8 +53,7 @@ namespace Sched {
     uint64_t ElfLoad(const char* vfsPath, uint64_t pml4Phys);
 
     // Load a shared library into a fixed address range.
-    // Loads at LIB_BASE for the given slot.
+    // Returns the relocation base / load bias on success, or 0 on failure.
-    // Returns the library base virtual address on success, or 0 on failure.
     uint64_t ElfLoadLib(const char* vfsPath, uint64_t pml4Phys, int slot);
 
 }

programs/include/libloader/libloader.h

@@ -10,13 +10,8 @@
 // Library handle - opaque to users
 struct LibHandle {
     int handle;       // syscall handle (slot + 1)
-    uint64_t base;    // base virtual address
+    uint64_t base;    // relocation base / load bias for symbol values
     char path[256];
-    int symbolCount;
-    struct SymbolEntry {
-        char name[64];
-        uint64_t offset;
-    }* symbols;
 };
 
 namespace libloader {

programs/libs/libhello/Makefile

@@ -1,5 +1,5 @@
 # Makefile for libhello shared library
-# Builds libhello.lib at fixed address 0x400000 (relocated at load time)
+# Builds libhello.lib as an ELF shared object (ET_DYN).
 
 # Target architecture.
 ARCH := x86_64
@@ -7,12 +7,12 @@ ARCH := x86_64
 # Toolchain
 TOOLCHAIN_PREFIX := $(shell cd ../../.. && pwd)/toolchain/local/bin/x86_64-elf-
 CXX := $(TOOLCHAIN_PREFIX)g++
+LD := $(TOOLCHAIN_PREFIX)ld
 NM := $(TOOLCHAIN_PREFIX)nm
 STRIP := $(TOOLCHAIN_PREFIX)strip
 
 # Compiler flags: freestanding, no stdlib
-# Build as PIE so library-internal data references remain valid after the
+# Build as PIC so the final ET_DYN image can be relocated by the kernel loader.
-# kernel maps the image into a per-process library slot.
 override CXXFLAGS := \
     -std=gnu++20 \
     -g -O2 -pipe \
@@ -22,7 +22,7 @@ override CXXFLAGS := \
     -ffreestanding \
     -fno-stack-protector \
     -fno-stack-check \
-    -fPIE \
+    -fPIC \
     -fno-rtti \
     -fno-exceptions \
     -ffunction-sections \
@@ -40,14 +40,13 @@ override CXXFLAGS := \
     -isystem ../../../kernel/freestnd-c-hdrs/x86_64/include \
     -isystem ../../../kernel/freestnd-cxx-hdrs/x86_64/include
 
-# Linker flags: freestanding static ELF at fixed address
+# Linker flags for a bare-metal ELF shared object.
-# Note: NOT using --gc-sections so all functions are kept
 override LDFLAGS := \
-    -nostdlib \
+    -shared \
-    -static \
+    --build-id=none \
-    -Wl,--build-id=none \
+    --hash-style=sysv \
-    -Wl,-m,elf_x86_64 \
+    -m elf_x86_64 \
-    -T link.ld
+    -z max-page-size=0x1000
 
 # Output
 OUTDIR := ../../bin/os
@@ -56,7 +55,7 @@ LIBSRC := src/libhello.cpp
 
 .PHONY: all clean
 
-all: $(OUTDIR)/$(LIBNAME).lib $(OUTDIR)/$(LIBNAME).lib.sym
+all: $(OUTDIR)/$(LIBNAME).lib
 
 $(OUTDIR):
 	mkdir -p $@
@@ -68,16 +67,8 @@ src/stb_truetype_impl.o: src/stb_truetype_impl.cpp Makefile | $(OUTDIR)
 	$(CXX) $(CXXFLAGS) -c src/stb_truetype_impl.cpp -o $@
 
 $(OUTDIR)/$(LIBNAME).lib: src/libhello.o src/stb_truetype_impl.o
-	$(CXX) $(CXXFLAGS) $(LDFLAGS) src/libhello.o src/stb_truetype_impl.o -o $@
+	rm -f $(OUTDIR)/$(LIBNAME).lib.sym
-
+	$(LD) $(LDFLAGS) src/libhello.o src/stb_truetype_impl.o -o $@
-# Generate symbol file from nm output
-# Format: "symbol_name,offset_in_hex"
-$(OUTDIR)/$(LIBNAME).lib.sym: $(OUTDIR)/$(LIBNAME).lib
-	@mkdir -p $(OUTDIR)
-	@echo "# Symbol table for $(LIBNAME)" > $@
-	@echo "# This file maps symbol names to offsets from library base" >> $@
-	@$(NM) $(OUTDIR)/$(LIBNAME).lib | grep ' T ' | awk '{printf "%s,0x%x\n", $$3, strtonum("0x" $$1) - 0x400000}' >> $@
-	@echo "Generated symbol file: $@"
 
 clean:
 	rm -rf ../../bin/os/$(LIBNAME).lib ../../bin/os/$(LIBNAME).lib.sym src/libhello.o src/stb_truetype_impl.o

programs/libs/libmath/Makefile

@@ -1,5 +1,5 @@
 # Makefile for libmath shared library
-# Builds libmath.lib at fixed address 0x400000 (relocated at load time)
+# Builds libmath.lib as an ELF shared object (ET_DYN).
 
 # Target architecture.
 ARCH := x86_64
@@ -7,12 +7,12 @@ ARCH := x86_64
 # Toolchain
 TOOLCHAIN_PREFIX := $(shell cd ../../.. && pwd)/toolchain/local/bin/x86_64-elf-
 CXX := $(TOOLCHAIN_PREFIX)g++
+LD := $(TOOLCHAIN_PREFIX)ld
 NM := $(TOOLCHAIN_PREFIX)nm
 STRIP := $(TOOLCHAIN_PREFIX)strip
 
 # Compiler flags: freestanding, no stdlib
-# Build as PIE so library code remains valid when loaded into a slot-specific
+# Build as PIC so the final ET_DYN image can be relocated by the kernel loader.
-# base address by the kernel loader.
 override CXXFLAGS := \
     -std=gnu++20 \
     -g -O2 -pipe \
@@ -22,7 +22,7 @@ override CXXFLAGS := \
     -ffreestanding \
     -fno-stack-protector \
     -fno-stack-check \
-    -fPIE \
+    -fPIC \
     -fno-rtti \
     -fno-exceptions \
     -ffunction-sections \
@@ -39,14 +39,13 @@ override CXXFLAGS := \
     -isystem ../../include/libc \
     -isystem ../../include/montauk
 
-# Linker flags: freestanding static ELF at fixed address
+# Linker flags for a bare-metal ELF shared object.
-# Note: NOT using --gc-sections so all functions are kept
 override LDFLAGS := \
-    -nostdlib \
+    -shared \
-    -static \
+    --build-id=none \
-    -Wl,--build-id=none \
+    --hash-style=sysv \
-    -Wl,-m,elf_x86_64 \
+    -m elf_x86_64 \
-    -T link.ld
+    -z max-page-size=0x1000
 
 # Output
 OUTDIR := ../../bin/os
@@ -55,21 +54,13 @@ LIBSRC := src/libmath.cpp
 
 .PHONY: all clean
 
-all: $(OUTDIR)/$(LIBNAME).lib $(OUTDIR)/$(LIBNAME).lib.sym
+all: $(OUTDIR)/$(LIBNAME).lib
 
 $(OUTDIR)/$(LIBNAME).lib: $(LIBSRC) Makefile
 	@mkdir -p $(OUTDIR)
+	rm -f $(OUTDIR)/$(LIBNAME).lib.sym
 	$(CXX) $(CXXFLAGS) -c $(LIBSRC) -o src/libmath.o
-	$(CXX) $(CXXFLAGS) $(LDFLAGS) src/libmath.o -o $@
+	$(LD) $(LDFLAGS) src/libmath.o -o $@
-
-# Generate symbol file from nm output
-# Format: "symbol_name,offset_in_hex"
-$(OUTDIR)/$(LIBNAME).lib.sym: $(OUTDIR)/$(LIBNAME).lib
-	@mkdir -p $(OUTDIR)
-	@echo "# Symbol table for $(LIBNAME)" > $@
-	@echo "# This file maps symbol names to offsets from library base" >> $@
-	@$(NM) $(OUTDIR)/$(LIBNAME).lib | grep ' T ' | awk '{printf "%s,0x%x\n", $$3, strtonum("0x" $$1) - 0x400000}' >> $@
-	@echo "Generated symbol file: $@"
 
 clean:
 	rm -rf ../../bin/os/$(LIBNAME).lib ../../bin/os/$(LIBNAME).lib.sym src/libmath.o

programs/src/libloader/libloader.cpp

@@ -11,15 +11,189 @@
 
 namespace libloader {
 
-// Forward declaration
-static uint64_t hexToUint64(const char* str);
-
 // Table of currently loaded libraries
 static LibHandle g_loadedLibs[MaxLoadedLibs];
-static int g_libCount = 0;
+
+namespace {
+
+struct Elf64Header {
+    uint8_t  e_ident[16];
+    uint16_t e_type;
+    uint16_t e_machine;
+    uint32_t e_version;
+    uint64_t e_entry;
+    uint64_t e_phoff;
+    uint64_t e_shoff;
+    uint32_t e_flags;
+    uint16_t e_ehsize;
+    uint16_t e_phentsize;
+    uint16_t e_phnum;
+    uint16_t e_shentsize;
+    uint16_t e_shnum;
+    uint16_t e_shstrndx;
+};
+
+struct Elf64SectionHeader {
+    uint32_t sh_name;
+    uint32_t sh_type;
+    uint64_t sh_flags;
+    uint64_t sh_addr;
+    uint64_t sh_offset;
+    uint64_t sh_size;
+    uint32_t sh_link;
+    uint32_t sh_info;
+    uint64_t sh_addralign;
+    uint64_t sh_entsize;
+};
+
+struct Elf64Sym {
+    uint32_t st_name;
+    uint8_t  st_info;
+    uint8_t  st_other;
+    uint16_t st_shndx;
+    uint64_t st_value;
+    uint64_t st_size;
+};
+
+static constexpr uint16_t ET_EXEC = 2;
+static constexpr uint16_t ET_DYN = 3;
+static constexpr uint16_t EM_X86_64 = 62;
+static constexpr uint32_t SHT_SYMTAB = 2;
+static constexpr uint32_t SHT_STRTAB = 3;
+static constexpr uint32_t SHT_DYNSYM = 11;
+static constexpr uint16_t SHN_UNDEF = 0;
+
+static bool readFile(const char* path, uint8_t** outBuf, uint64_t* outSize) {
+    *outBuf = nullptr;
+    *outSize = 0;
+
+    int fd = montauk::open(path);
+    if (fd < 0) return false;
+
+    uint64_t size = montauk::getsize(fd);
+    if (size < sizeof(Elf64Header) || size > (1 << 20)) {
+        montauk::close(fd);
+        return false;
+    }
+
+    auto* buf = (uint8_t*)montauk::alloc(size);
+    if (!buf) {
+        montauk::close(fd);
+        return false;
+    }
+
+    int read = montauk::read(fd, buf, 0, size);
+    montauk::close(fd);
+    if (read != (int)size) {
+        montauk::free(buf);
+        return false;
+    }
+
+    *outBuf = buf;
+    *outSize = size;
+    return true;
+}
+
+static bool isValidElf(const Elf64Header* hdr, uint64_t size) {
+    if (size < sizeof(Elf64Header)) return false;
+    if (hdr->e_ident[0] != 0x7f || hdr->e_ident[1] != 'E' ||
+        hdr->e_ident[2] != 'L' || hdr->e_ident[3] != 'F') {
+        return false;
+    }
+    if (hdr->e_ident[4] != 2 || hdr->e_ident[5] != 1) return false;
+    if (hdr->e_machine != EM_X86_64) return false;
+    if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) return false;
+    if (hdr->e_shentsize != sizeof(Elf64SectionHeader)) return false;
+    if (hdr->e_shoff == 0 || hdr->e_shnum == 0) return false;
+    if (hdr->e_shoff + uint64_t(hdr->e_shnum) * hdr->e_shentsize > size) return false;
+    if (hdr->e_shstrndx >= hdr->e_shnum) return false;
+    return true;
+}
+
+static const Elf64SectionHeader* getSectionHeaders(const Elf64Header* hdr) {
+    return (const Elf64SectionHeader*)((const uint8_t*)hdr + hdr->e_shoff);
+}
+
+static const char* getSectionNameTable(const Elf64Header* hdr, uint64_t fileSize) {
+    const Elf64SectionHeader* shdrs = getSectionHeaders(hdr);
+    const Elf64SectionHeader& strhdr = shdrs[hdr->e_shstrndx];
+    if (strhdr.sh_type != SHT_STRTAB) return nullptr;
+    if (strhdr.sh_offset + strhdr.sh_size > fileSize) return nullptr;
+    return (const char*)hdr + strhdr.sh_offset;
+}
+
+static const Elf64SectionHeader* findSection(const Elf64Header* hdr, uint64_t fileSize,
+                                             const char* name, uint32_t expectedType) {
+    const Elf64SectionHeader* shdrs = getSectionHeaders(hdr);
+    const char* shstrtab = getSectionNameTable(hdr, fileSize);
+    if (!shstrtab) return nullptr;
+
+    for (uint16_t i = 0; i < hdr->e_shnum; i++) {
+        const Elf64SectionHeader* sh = &shdrs[i];
+        if (sh->sh_name >= shdrs[hdr->e_shstrndx].sh_size) continue;
+        if (sh->sh_type != expectedType) continue;
+        const char* secName = shstrtab + sh->sh_name;
+        if (strcmp(secName, name) == 0) return sh;
+    }
+    return nullptr;
+}
+
+static bool lookupSymbolValue(const char* path, const char* symbolName, uint64_t* outValue) {
+    uint8_t* fileData = nullptr;
+    uint64_t fileSize = 0;
+    if (!readFile(path, &fileData, &fileSize)) return false;
+
+    const Elf64Header* hdr = (const Elf64Header*)fileData;
+    if (!isValidElf(hdr, fileSize)) {
+        montauk::free(fileData);
+        return false;
+    }
+
+    const Elf64SectionHeader* symtab = findSection(hdr, fileSize, ".dynsym", SHT_DYNSYM);
+    const Elf64SectionHeader* strtab = findSection(hdr, fileSize, ".dynstr", SHT_STRTAB);
+    if (!symtab || !strtab) {
+        symtab = findSection(hdr, fileSize, ".symtab", SHT_SYMTAB);
+        strtab = findSection(hdr, fileSize, ".strtab", SHT_STRTAB);
+    }
+
+    if (!symtab || !strtab || symtab->sh_entsize != sizeof(Elf64Sym) ||
+        symtab->sh_offset + symtab->sh_size > fileSize ||
+        strtab->sh_offset + strtab->sh_size > fileSize) {
+        montauk::free(fileData);
+        return false;
+    }
+
+    const Elf64Sym* symbols = (const Elf64Sym*)(fileData + symtab->sh_offset);
+    const char* strings = (const char*)(fileData + strtab->sh_offset);
+    uint64_t count = symtab->sh_size / sizeof(Elf64Sym);
+
+    bool found = false;
+    for (uint64_t i = 0; i < count; i++) {
+        const Elf64Sym& sym = symbols[i];
+        if (sym.st_shndx == SHN_UNDEF || sym.st_name >= strtab->sh_size) continue;
+        const char* name = strings + sym.st_name;
+        if (strcmp(name, symbolName) == 0) {
+            *outValue = sym.st_value;
+            found = true;
+            break;
+        }
+    }
+
+    montauk::free(fileData);
+    return found;
+}
+
+static LibHandle* findFreeLib() {
+    for (int i = 0; i < MaxLoadedLibs; i++) {
+        if (g_loadedLibs[i].handle <= 0) return &g_loadedLibs[i];
+    }
+    return nullptr;
+}
+
+} // namespace
 
 static LibHandle* findLoadedLib(const char* path) {
-    for (int i = 0; i < g_libCount; i++) {
+    for (int i = 0; i < MaxLoadedLibs; i++) {
         if (g_loadedLibs[i].handle > 0 &&
             strcmp(g_loadedLibs[i].path, path) == 0) {
             return &g_loadedLibs[i];
@@ -28,102 +202,6 @@ static LibHandle* findLoadedLib(const char* path) {
     return nullptr;
 }
 
-static bool parseSymbolFile(const char* symPath, LibHandle* lib) {
-    int fd = montauk::open(symPath);
-    if (fd < 0) {
-        // No symbol file - that's okay, we'll still load the lib
-        lib->symbolCount = 0;
-        lib->symbols = nullptr;
-        return true;
-    }
-
-    uint64_t size = montauk::getsize(fd);
-    if (size == 0 || size > 65536) {
-        montauk::close(fd);
-        lib->symbolCount = 0;
-        lib->symbols = nullptr;
-        return true;
-    }
-
-    char* buf = (char*)montauk::alloc(size + 1);
-    if (!buf) {
-        montauk::close(fd);
-        return false;
-    }
-
-    int read = montauk::read(fd, (uint8_t*)buf, 0, size);
-    montauk::close(fd);
-    if (read != (int)size) {
-        montauk::free(buf);
-        return false;
-    }
-    buf[size] = '\0';
-
-    // Count lines first
-    int lineCount = 0;
-    for (uint64_t i = 0; i < size; i++) {
-        if (buf[i] == '\n') lineCount++;
-    }
-
-    if (lineCount == 0) {
-        montauk::free(buf);
-        lib->symbolCount = 0;
-        lib->symbols = nullptr;
-        return true;
-    }
-
-    lib->symbols = (LibHandle::SymbolEntry*)montauk::alloc(lineCount * sizeof(LibHandle::SymbolEntry));
-    if (!lib->symbols) {
-        montauk::free(buf);
-        return false;
-    }
-
-    lib->symbolCount = lineCount;
-
-    // Parse lines: "symbol_name,offset_hex"
-    int entryIdx = 0;
-    char* lineStart = buf;
-    for (uint64_t i = 0; i <= size; i++) {
-        if (buf[i] == '\n' || buf[i] == '\0') {
-            buf[i] = '\0';
-            char* comma = strchr(lineStart, ',');
-            if (comma && entryIdx < lineCount) {
-                size_t nameLen = comma - lineStart;
-                if (nameLen < sizeof(lib->symbols[0].name) - 1) {
-                    memcpy(lib->symbols[entryIdx].name, lineStart, nameLen);
-                    lib->symbols[entryIdx].name[nameLen] = '\0';
-                    lib->symbols[entryIdx].offset = hexToUint64(comma + 1);
-                    entryIdx++;
-                }
-            }
-            lineStart = &buf[i + 1];
-        }
-    }
-
-    lib->symbolCount = entryIdx;
-    montauk::free(buf);
-    return true;
-}
-
-static uint64_t hexToUint64(const char* str) {
-    uint64_t result = 0;
-    // Skip optional "0x" prefix
-    if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X')) {
-        str += 2;
-    }
-    while (*str) {
-        char c = *str;
-        uint64_t val = 0;
-        if (c >= '0' && c <= '9') val = c - '0';
-        else if (c >= 'a' && c <= 'f') val = c - 'a' + 10;
-        else if (c >= 'A' && c <= 'F') val = c - 'A' + 10;
-        else break;
-        result = (result << 4) | val;
-        str++;
-    }
-    return result;
-}
-
 LibHandle* dlopen(const char* path) {
     if (!path) return nullptr;
 
@@ -134,33 +212,21 @@ LibHandle* dlopen(const char* path) {
         return existing;
     }
 
-    if (g_libCount >= MaxLoadedLibs) {
-        return nullptr;
-    }
-
     // Load the library via syscall
     int handle = montauk::load_lib(path);
     if (handle <= 0) {
         return nullptr;
     }
 
-    // Create symbol file path: append ".sym"
+    LibHandle* lib = findFreeLib();
-    char symPath[320];
+    if (!lib) {
-    size_t pathLen = strlen(path);
+        montauk::unload_lib(handle);
-    if (pathLen >= sizeof(symPath) - 5) return nullptr;
+        return nullptr;
+    }
 
-    strcpy(symPath, path);
-    strcpy(symPath + pathLen, ".sym");
-
-    LibHandle* lib = &g_loadedLibs[g_libCount++];
     lib->handle = handle;
-    lib->base = 0;  // Will be retrieved on first dlsym
+    lib->base = montauk::get_libbase(handle);
     strcpy(lib->path, path);
-    lib->symbolCount = 0;
-    lib->symbols = nullptr;
-
-    // Parse symbol file
-    parseSymbolFile(symPath, lib);
 
     return lib;
 }
@@ -173,15 +239,9 @@ void* dlsym(LibHandle* lib, const char* symbolName) {
         lib->base = montauk::get_libbase(lib->handle);
     }
 
-    // Look up in symbol table
+    uint64_t value = 0;
-    for (int i = 0; i < lib->symbolCount; i++) {
+    if (!lookupSymbolValue(lib->path, symbolName, &value)) return nullptr;
-        if (strcmp(lib->symbols[i].name, symbolName) == 0) {
+    return (void*)(lib->base + value);
-            uint64_t offset = lib->symbols[i].offset;
-            return (void*)montauk::dlsym(lib->handle, offset);
-        }
-    }
-
-    return nullptr;  // Symbol not found
 }
 
 int dlclose(LibHandle* lib) {
@@ -189,14 +249,8 @@ int dlclose(LibHandle* lib) {
 
     int result = montauk::unload_lib(lib->handle);
     if (result == 0) {
-        // Free symbol table if allocated
-        if (lib->symbols) {
-            montauk::free((void*)lib->symbols);
-            lib->symbols = nullptr;
-        }
         lib->handle = 0;
         lib->base = 0;
-        lib->symbolCount = 0;
         lib->path[0] = '\0';
     }
 

programs/src/test_dl/Makefile

@@ -49,7 +49,7 @@ LIBDIR := ../../bin
 
 all: $(BINDIR)/test_dl.elf
 
-$(BINDIR)/test_dl.elf: main.cpp
+$(BINDIR)/test_dl.elf: main.cpp Makefile $(LIBDIR)/liblibloader.a ../../lib/libc/liblibc.a
 	@mkdir -p $(BINDIR)
 	$(CXX) $(CXXFLAGS) -c main.cpp -o main.o
 	$(CXX) $(CXXFLAGS) $(LDFLAGS) main.o $(LIBDIR)/liblibloader.a ../../lib/libc/liblibc.a -o $@