15 files changed, 1045 insertions, 0 deletions
diff --git a/src/libSystem/SystemKit/Err.h b/src/libSystem/SystemKit/Err.h
new file mode 100644
index 00000000..ea36abde
--- /dev/null
+++ b/src/libSystem/SystemKit/Err.h
@@ -0,0 +1,58 @@
+/* ========================================
+
+  Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#pragma once
+
+#include <libSystem/SystemKit/Macros.h>
+
+/// @file Err.h
+/// @brief Process Codes type and values.
+/// @author Amlal El Mahrouss (amlal@nekernel.org)
+
+#define err_local_ok() (kLastError == kErrorSuccess)
+#define err_local_fail() (kLastError != kErrorSuccess)
+#define err_local_get() (kLastError)
+
+typedef SInt32 ErrRef;
+
+inline constexpr ErrRef kErrorSuccess            = 0;
+inline constexpr ErrRef kErrorExecutable         = 33;
+inline constexpr ErrRef kErrorExecutableLib      = 34;
+inline constexpr ErrRef kErrorFileNotFound       = 35;
+inline constexpr ErrRef kErrorDirectoryNotFound  = 36;
+inline constexpr ErrRef kErrorDiskReadOnly       = 37;
+inline constexpr ErrRef kErrorDiskIsFull         = 38;
+inline constexpr ErrRef kErrorProcessFault       = 39;
+inline constexpr ErrRef kErrorSocketHangUp       = 40;
+inline constexpr ErrRef kErrorThreadLocalStorage = 41;
+inline constexpr ErrRef kErrorMath               = 42;
+inline constexpr ErrRef kErrorNoNetwork          = 43;
+inline constexpr ErrRef kErrorHeapOutOfMemory    = 44;
+inline constexpr ErrRef kErrorNoSuchDisk         = 45;
+inline constexpr ErrRef kErrorFileExists         = 46;
+inline constexpr ErrRef kErrorFormatFailed       = 47;
+inline constexpr ErrRef kErrorNetworkTimeout     = 48;
+inline constexpr ErrRef kErrorInternal           = 49;
+inline constexpr ErrRef kErrorForkAlreadyExists  = 50;
+inline constexpr ErrRef kErrorOutOfTeamSlot      = 51;
+inline constexpr ErrRef kErrorHeapNotPresent     = 52;
+inline constexpr ErrRef kErrorNoEntrypoint       = 53;
+inline constexpr ErrRef kErrorDiskIsCorrupted    = 54;
+inline constexpr ErrRef kErrorDisk               = 55;
+inline constexpr ErrRef kErrorInvalidData        = 56;
+inline constexpr ErrRef kErrorAsync              = 57;
+inline constexpr ErrRef kErrorNonBlocking        = 58;
+inline constexpr ErrRef kErrorIPC                = 59;
+inline constexpr ErrRef kErrorSign               = 60;
+inline constexpr ErrRef kErrorInvalidCreds       = 61;
+inline constexpr ErrRef kErrorCDTrayBroken       = 62;
+inline constexpr ErrRef kErrorUnrecoverableDisk  = 63;
+inline constexpr ErrRef kErrorFileLocked         = 64;
+inline constexpr ErrRef kErrorDiskIsTooTiny      = 65;
+inline constexpr ErrRef kErrorUnimplemented      = -1;
+
+/// @brief The last error reported by the system to the process.
+IMPORT_C ErrRef kLastError;
diff --git a/src/libSystem/SystemKit/Jail.h b/src/libSystem/SystemKit/Jail.h
new file mode 100644
index 00000000..f28968b4
--- /dev/null
+++ b/src/libSystem/SystemKit/Jail.h
@@ -0,0 +1,36 @@
+/* ========================================
+
+  Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#pragma once
+
+#include <libSystem/SystemKit/System.h>
+
+/// @file Jail.h
+/// @author Amlal El Mahrouss
+/// @brief NeKernel Jail System, part of OpenEnclave.
+
+struct JAIL_INFO;
+struct JAIL;
+
+/// @brief Jail information (client side struct)
+struct JAIL_INFO {
+  SInt32 fParentID;
+  SInt32 fJailHash;
+  SInt64 fACL;
+};
+
+/// @brief Jail information (we grab a JAIL from JailGetCurrent())
+struct JAIL {
+  struct JAIL_INFO* fServer;
+  struct JAIL_INFO* fClient;
+  SInt32            fJailHash;
+  SInt32            fParentID;
+  SInt64            fACL;
+};
+
+/// @brief Get the current jail
+/// @return Pointer to the current jail structure, or NULL if not in a jail
+IMPORT_C struct JAIL* JailGetCurrent(Void);
diff --git a/src/libSystem/SystemKit/Macros.h b/src/libSystem/SystemKit/Macros.h
new file mode 100644
index 00000000..aac2bf1b
--- /dev/null
+++ b/src/libSystem/SystemKit/Macros.h
@@ -0,0 +1,126 @@
+/* ========================================
+
+Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+File: Macros.h
+Purpose: libsci Macros header.
+
+======================================== */
+
+#pragma once
+
+/***********************************************************************************/
+/// @file libSystem/Macros.h
+/// @brief Macros and Core types of the SCI (System Call Interface).
+/***********************************************************************************/
+
+#include <hint/CompilerHint.h>
+
+#define ATTRIBUTE(X) __attribute__((X))
+
+#define IMPORT_CXX extern "C++"
+#define IMPORT_C extern "C"
+
+#define DEPRECATED ATTRIBUTE(deprecated)
+
+#define EXIT_SUCCESS (0)
+#define EXIT_FAILURE (1)
+
+#define FILE_MAX_LEN (256)
+
+#ifndef BOOL
+#define BOOL bool
+#endif
+
+typedef bool Bool;
+typedef bool Boolean;
+typedef void Void;
+
+#ifndef __cplusplus
+#define true (1)
+#define false (0)
+#endif
+
+#define YES true
+#define NO false
+
+typedef __UINT64_TYPE__ UInt64;
+typedef __UINT32_TYPE__ UInt32;
+typedef __UINT16_TYPE__ UInt16;
+typedef __UINT8_TYPE__  UInt8;
+
+typedef __SIZE_TYPE__ SizeT;
+
+typedef __INT64_TYPE__ SInt64;
+typedef __INT32_TYPE__ SInt32;
+typedef __INT16_TYPE__ SInt16;
+typedef __INT8_TYPE__  SInt8;
+
+typedef void*            VoidPtr;
+typedef __UINTPTR_TYPE__ UIntPtr;
+typedef char             Char;
+
+#ifdef __cplusplus
+typedef decltype(nullptr) nullPtr;
+typedef nullPtr           NullPtr;
+
+#define LIBSYS_COPY_DELETE(KLASS)          \
+  KLASS& operator=(const KLASS&) = delete; \
+  KLASS(const KLASS&)            = delete;
+
+#define LIBSYS_COPY_DEFAULT(KLASS)          \
+  KLASS& operator=(const KLASS&) = default; \
+  KLASS(const KLASS&)            = default;
+
+#define LIBSYS_MOVE_DELETE(KLASS)     \
+  KLASS& operator=(KLASS&&) = delete; \
+  KLASS(KLASS&&)            = delete;
+
+#define LIBSYS_MOVE_DEFAULT(KLASS)     \
+  KLASS& operator=(KLASS&&) = default; \
+  KLASS(KLASS&&)            = default;
+
+#endif
+
+#define MUST_PASS(X) _rtl_assert(X, __FILE__)
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(X) \
+  (((sizeof(X) / sizeof(*(X))) / (static_cast<SizeT>(!(sizeof(X) % sizeof(*(X)))))))
+#endif
+
+#ifndef KIB
+#define KIB(X) (UInt64)((X) / 1024)
+#endif
+
+#ifndef kib_cast
+#define kib_cast(X) (UInt64)((X) *1024)
+#endif
+
+#ifndef MIB
+#define MIB(X) (UInt64)((UInt64) KIB(X) / 1024)
+#endif
+
+#ifndef mib_cast
+#define mib_cast(X) (UInt64)((UInt64) kib_cast(X) * 1024)
+#endif
+
+#ifndef GIB
+#define GIB(X) (UInt64)((UInt64) MIB(X) / 1024)
+#endif
+
+#ifndef gib_cast
+#define gib_cast(X) (UInt64)((UInt64) mib_cast(X) * 1024)
+#endif
+
+#ifndef TIB
+#define TIB(X) (UInt64)((UInt64) GIB(X) / 1024)
+#endif
+
+#ifndef tib_cast
+#define tib_cast(X) ((UInt64) gib_cast(X) * 1024)
+#endif
+
+#define LIBSYS_UNUSED(X) ((void) X)
+
+IMPORT_C void _rtl_assert(Bool expr, const Char* origin);
diff --git a/src/libSystem/SystemKit/Syscall.h b/src/libSystem/SystemKit/Syscall.h
new file mode 100644
index 00000000..58d7d7f1
--- /dev/null
+++ b/src/libSystem/SystemKit/Syscall.h
@@ -0,0 +1,21 @@
+/* ========================================
+
+  Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#pragma once
+
+#include <libSystem/SystemKit/System.h>
+#include <cstdarg>
+
+IMPORT_C VoidPtr libsys_syscall_arg_1(SizeT id);
+IMPORT_C VoidPtr libsys_syscall_arg_2(SizeT id, VoidPtr arg1);
+IMPORT_C VoidPtr libsys_syscall_arg_3(SizeT id, VoidPtr arg1, VoidPtr arg3);
+IMPORT_C VoidPtr libsys_syscall_arg_4(SizeT id, VoidPtr arg1, VoidPtr arg3, VoidPtr arg4);
+
+IMPORT_C UInt64 libsys_hash_64(const Char* path);
+
+#ifndef SYSCALL_HASH
+#define SYSCALL_HASH(str) libsys_hash_64(str)
+#endif  // !SYSCALL_HASH
diff --git a/src/libSystem/SystemKit/System.h b/src/libSystem/SystemKit/System.h
new file mode 100644
index 00000000..544b7ee3
--- /dev/null
+++ b/src/libSystem/SystemKit/System.h
@@ -0,0 +1,389 @@
+/* ========================================
+
+Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+File: System.h
+Purpose: System Call Interface.
+
+======================================== */
+
+#ifndef LIBSYS_SYSTEM_CALLS_H
+#define LIBSYS_SYSTEM_CALLS_H
+
+#include <libSystem/SystemKit/Macros.h>
+
+/// @brief TTY device path.
+#define kPrintDevicePath "/devices/tty{}"
+#define kCDDevicePath "/devices/dvd{}"
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Types API.
+// ------------------------------------------------------------------------------------------ //
+
+struct REF_TYPE {
+  UInt64  __hash;  /// @brief Hash of the syscall
+  VoidPtr __self;  /// @brief Syscall self value.
+};
+
+typedef REF_TYPE* Ref;
+
+typedef Ref IORef;
+typedef Ref FSRef;
+typedef Ref DylibRef;
+typedef Ref ThreadRef;
+typedef Ref SocketRef;
+typedef Ref NetworkRef;
+typedef Ref MutexRef;
+typedef Ref EventRef;
+typedef Ref SemaphoreRef;
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Dynamic Loader API.
+// ------------------------------------------------------------------------------------------ //
+
+/// @brief Get function which is part of the Dylib.
+/// @param symbol the symbol to look for
+/// @param dll_handle the Dylib handle.
+/// @return the proc pointer.
+IMPORT_C Ref LdrGetDylibSymbolFromHandle(_Input const Char* symbol, _Input Ref dll_handle);
+
+/// @brief Open Dylib handle.
+/// @param path dll path.
+/// @param drv driver letter.
+/// @return a dylib ref.
+IMPORT_C Ref LdrOpenDylibHandle(_Input const Char* path, _Input const Char* drive_letter);
+
+/// @brief Close Dylib handle
+/// @param dll_handle the dylib ref.
+/// @return whether it closed or not.
+IMPORT_C UInt32 LdrCloseDylibHandle(_Input Ref* dll_handle);
+
+// ------------------------------------------------------------------------------------------ //
+// File API.
+// ------------------------------------------------------------------------------------------ //
+
+/// @brief Opens a file from a drive.
+/// @param fs_path the filesystem path.
+/// @param drive_letter drive name, use NULL to use default drive location.
+/// @return the file descriptor of the file.
+IMPORT_C Ref IoOpenFile(const Char* fs_path, const Char* drive_letter);
+
+/// @brief Closes a file and flushes its content.
+/// @param file_desc the file descriptor.
+/// @return Function doesn't return a type.
+IMPORT_C Void IoCloseFile(_Input Ref file_desc);
+
+/// @brief I/O control (ioctl) on a file.
+/// @param file_desc the file descriptor.
+/// @param ioctl_code the ioctl code.
+/// @param in_data the input data.
+/// @param out_data the output data.
+/// @return the number of bytes written.
+/// @note This function is used to control the file descriptor, introduced for OpenHeFS.
+IMPORT_C SInt32 IoCtrlFile(_Input Ref file_desc, _Input UInt32 ioctl_code, _Input VoidPtr in_data,
+                           _Output VoidPtr out_data);
+
+/// @brief Gets the file mime (if any)
+/// @param file_desc the file descriptor.
+IMPORT_C const Char* IoMimeFile(_Input Ref file_desc);
+
+/// @brief Gets the dir DIM.
+/// @param dir_desc directory descriptor.
+/// @note only works in OpenHeFS, will return nil-x/nil if used on any other filesystem.
+IMPORT_C const Char* IoDimFile(_Input Ref dir_desc);
+
+/// @brief Write data to a file ref
+/// @param file_desc the file descriptor.
+/// @param out_data the data to write.
+/// @param sz_data the size of the data to write.
+/// @return the number of bytes written.
+IMPORT_C UInt32 IoWriteFile(_Input Ref file_desc, _Output VoidPtr out_data, SizeT sz_data);
+
+/// @brief Read data from a file.
+/// @param file_desc the file descriptor.
+/// @param out_data the data to read.
+/// @param sz_data the size of the data to read.
+IMPORT_C UInt32 IoReadFile(_Input Ref file_desc, _Output VoidPtr* out_data, SizeT sz_data);
+
+/// @brief Rewind the file pointer to the beginning of the file.
+/// @param file_desc the file descriptor.
+/// @return the number of bytes read.
+IMPORT_C UInt64 IoRewindFile(_Input Ref file_desc);
+
+/// @brief Tell the current position of the file pointer.
+/// @param file_desc the file descriptor.
+/// @return the current position of the file pointer.
+IMPORT_C UInt64 IoTellFile(_Input Ref file_desc);
+
+/// @brief Seek file offset from file descriptor.
+IMPORT_C UInt64 IoSeekFile(_Input Ref file_desc, UInt64 file_offset);
+
+// ------------------------------------------------------------------------
+// Process API.
+// ------------------------------------------------------------------------
+
+/// @brief Spawns a Thread Information Block and Global Information Block inside the current
+/// process.
+/// @param process_id Target Process ID, must be valid.
+/// @return > 0 error occurred or already present, = 0 success.
+IMPORT_C UInt32 RtlSpawnIB(UIntPtr process_id);
+
+/// @brief Spawns a process with a unique pid (stored as UIntPtr).
+/// @param process_path process filesystem path.
+/// @return > 0 process was created.
+IMPORT_C UIntPtr RtlSpawnProcess(const Char* process_path, SizeT argc, Char** argv, Char** envp,
+                                 SizeT envp_len);
+
+/// @brief Exits a process with an exit_code.
+/// @return if it has succeeded true, otherwise false.
+IMPORT_C Bool RtlExitProcess(UIntPtr handle, UIntPtr exit_code);
+
+// ------------------------------------------------------------------------
+// Memory Manager API.
+// ------------------------------------------------------------------------
+
+/// @brief Creates a new heap from the process's address space.
+/// @param len the length of it.
+/// @param flags the flags of it.
+/// @return heap pointer.
+IMPORT_C VoidPtr MmCreateHeap(_Input SizeT len, _Input UInt32 flags);
+
+/// @brief Destroys the pointer
+/// @param heap the heap itself.
+/// @return void.
+IMPORT_C SInt32 MmDestroyHeap(_Input VoidPtr heap);
+
+/// @brief Change protection flags of a memory region.
+IMPORT_C SInt32 MmSetHeapFlags(_Input VoidPtr heap, _Input UInt32 flags);
+
+/// @brief Change protection flags of a memory region.
+IMPORT_C UInt32 MmGetHeapFlags(_Input VoidPtr heap);
+
+/// @brief Fill memory region with CRC32.
+IMPORT_C UInt32 MmFillCRC32Heap(_Input VoidPtr heap);
+
+/// @brief Copy memory region.
+IMPORT_C VoidPtr MmCopyMemory(_Input VoidPtr dest, _Input VoidPtr src, _Input SizeT len);
+
+/// @brief Compare memory regions.
+IMPORT_C SInt64 MmCmpMemory(_Input VoidPtr dest, _Input VoidPtr src, _Input SizeT len);
+
+/// @brief Fill memory region.
+IMPORT_C VoidPtr MmFillMemory(_Input VoidPtr dest, _Input SizeT len, _Input UInt8 value);
+
+/// @brief Compare string regions.
+IMPORT_C SInt64 MmStrCmp(_Input const Char* dest, _Input const Char* src);
+
+/// @brief Get length of string.
+IMPORT_C SInt64 MmStrLen(const Char* str);
+
+// ------------------------------------------------------------------------
+// @brief Error API.
+// ------------------------------------------------------------------------
+
+IMPORT_C SInt32 ErrGetLastError(Void);
+
+// ------------------------------------------------------------------------
+// @brief Threading API.
+// ------------------------------------------------------------------------
+
+/// @brief Exit the current thread.
+/// @param exit_code the exit code.
+IMPORT_C SInt32 ThrExitCurrentThread(_Input SInt32 exit_code);
+
+/// @brief Exit the main thread.
+/// @param exit_code the exit code.
+IMPORT_C SInt32 ThrExitMainThread(_Input SInt32 exit_code);
+
+/// @brief Exit a thread.
+/// @param thread the thread to exit.
+/// @param exit_code the exit code.
+IMPORT_C SInt32 ThrExitThread(_Input ThreadRef thread, _Input SInt32 exit_code);
+
+/// @brief Thread procedure function type.
+typedef SInt32 (*ThrProcKind)(SInt32 argc, Char** argv);
+
+/// @brief Creates a thread.
+/// @param procedure the thread procedure.
+/// @param argument_count number of arguments inside that thread.
+/// @param flags Thread flags.
+/// @return the thread object.
+IMPORT_C ThreadRef ThrCreateThread(const Char* thread_name, ThrProcKind procedure,
+                                   SInt32 argument_count, SInt32 flags);
+
+/// @brief Yields the current thread.
+/// @param thread the thread to yield.
+IMPORT_C SInt32 ThrYieldThread(ThreadRef thrd);
+
+/// @brief Joins a thread.
+/// @param thread the thread to join.
+IMPORT_C SInt32 ThrJoinThread(ThreadRef thrd);
+
+/// @brief Detach a thread.
+/// @param thread the thread to detach.
+IMPORT_C SInt32 ThrDetachThread(ThreadRef thrd);
+
+// ------------------------------------------------------------------------
+// @brief Drive Management API.
+// ------------------------------------------------------------------------
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Get the default drive letter.
+/// @param void.
+/// @return the drive letter.
+// ------------------------------------------------------------------------------------------ //
+IMPORT_C Char* DrvGetDefaultDriveLetter(Void);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Get the drive letter from a path.
+/// @param path the path.
+/// @return the drive letter.
+// ------------------------------------------------------------------------------------------ //
+IMPORT_C Char* DrvGetDriveLetterFromPath(_Input const Char* path);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Get a mounted drive from a letter.
+/// @param letter the letter (A..Z).
+/// @return the drive object.
+// ------------------------------------------------------------------------------------------ //
+IMPORT_C Ref DrvGetMountedDrive(_Input Char letter);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Mount a drive.
+/// @param path the path to mount.
+/// @param letter the letter to mount.
+// ------------------------------------------------------------------------------------------ //
+IMPORT_C Void DrvMountDrive(_Input const Char* path, _Input const Char* letter);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Unmount a drive.
+/// @param letter the letter to unmount.
+// ------------------------------------------------------------------------------------------ //
+IMPORT_C Void DrvUnmountDrive(_Input Char letter);
+
+// ------------------------------------------------------------------------
+// Event handling API, use to listen to OS specific events.
+// ------------------------------------------------------------------------
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Add an event listener.
+/// @param event_name the event name.
+/// @param listener the listener to add.
+/// @return the event listener.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C Void EvtAddListener(_Input const Char* event_name, _Input Ref listener);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Remove an event listener.
+/// @param event_name the event name.
+/// @param listener the listener to remove.
+/// @return the event listener.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C Void EvtRemoveListener(_Input const Char* event_name, _Input Ref listener);
+
+// ------------------------------------------------------------------------------------------ //
+/// @brief Dispatch an event.
+/// @param event_name the event name.
+/// @param event_data the event data.
+/// @return the event data.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C VoidPtr EvtDispatchEvent(_Input const Char* event_name, _Input VoidPtr event_data);
+
+// ------------------------------------------------------------------------------------------ //
+// Power API.
+// ------------------------------------------------------------------------------------------ //
+
+enum {
+  kPowerCodeInvalid  = 0,
+  kPowerCodeShutdown = 12,
+  kPowerCodeReboot,
+  kPowerCodeSleep,
+  kPowerCodeWake,
+  kPowerCodeCount,
+};
+
+IMPORT_C SInt32 PwrReadCode(_Output SInt32& code);
+
+IMPORT_C SInt32 PwrSendCode(_Output SInt32& code);
+
+// ------------------------------------------------------------------------------------------ //
+// CD-ROM API.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C IORef CdOpenTray(Void);
+
+IMPORT_C SInt32 CdEjectDrive(_Input IORef cdrom);
+
+IMPORT_C SInt32 CdCloseTray(Void);
+
+// ------------------------------------------------------------------------------------------ //
+// TTY API.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C SInt32 PrintOut(IORef file /* nullptr to direct to stdout */, const Char* fmt, ...);
+
+IMPORT_C SInt32 PrintIn(IORef file /* nullptr to direct to stdout */, const Char* fmt, ...);
+
+IMPORT_C IORef PrintCreate(Void);
+
+IMPORT_C SInt32 PrintRelease(IORef);
+
+IMPORT_C IORef PrintGet(const Char* path);
+
+// ------------------------------------------------------------------------------------------ //
+// @brief Scheduler/Debug API.
+// ------------------------------------------------------------------------------------------ //
+
+typedef SInt32 AffinityRef;
+typedef UInt64 ProcessRef;
+
+IMPORT_C SInt32 SchedSetAffinity(_Input ProcessRef, SInt32 req, _Input AffinityRef*);
+
+IMPORT_C SInt32 SchedGetAffinity(_Input ProcessRef, _InOut AffinityRef*);
+
+IMPORT_C SInt32 SchedFireSignal(_Input ProcessRef, SInt32);
+
+IMPORT_C SInt32 SchedReadMemory(_Input ProcessRef, SInt32, SInt32);
+
+IMPORT_C SInt32 SchedWriteMemory(_Input ProcessRef, SInt32, SInt32);
+
+IMPORT_C UIntPtr SchedGetCurrentProcessID(Void);
+
+// ------------------------------------------------------------------------------------------ //
+// @brief Filesystem API.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C BOOL FsCopy(const Char* path, const Char* dst);
+
+IMPORT_C BOOL FsMove(const Char* path, const Char* dst);
+
+IMPORT_C BOOL FsExists(const Char* path);
+
+IMPORT_C BOOL FsCreateDir(const Char* path);
+
+IMPORT_C BOOL FsCreateFile(const Char* path);
+
+IMPORT_C BOOL FsCreateAlias(const Char* path, const Char* from);
+
+// ------------------------------------------------------------------------------------------ //
+// @brief Installable Filesystem API.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C BOOL IfsMount(const Char* path, const Char* drive_letter);
+
+IMPORT_C BOOL IfsUnmount(const Char* drive_letter);
+
+IMPORT_C BOOL IfsIsMounted(const Char* drive_letter);
+
+// ------------------------------------------------------------------------------------------ //
+// @brief String Manip API.
+// ------------------------------------------------------------------------------------------ //
+
+IMPORT_C Char* StrFmt(const Char* fmt, ...);
+
+IMPORT_C UInt64 StrMathToNumber(const Char* in, const Char** endp, const SInt16 base);
+
+#endif  // ifndef LIBSYS_SYSTEM_CALLS_H
diff --git a/src/libSystem/SystemKit/Verify.h b/src/libSystem/SystemKit/Verify.h
new file mode 100644
index 00000000..7d15435a
--- /dev/null
+++ b/src/libSystem/SystemKit/Verify.h
@@ -0,0 +1,40 @@
+/* ========================================
+
+   Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+   File: Verify.h
+   Purpose: System Call Interface Verification Layer.
+
+   ======================================== */
+
+#pragma once
+
+#include <libSystem/SystemKit/System.h>
+
+namespace LibSystem::Verify {
+/// @author 0xf00sec, and Amlal El Mahrouss
+/// @brief safe cast operator.
+template <typename T, typename R = VoidPtr>
+inline R sys_safe_cast(const T* ptr) {
+  _rtl_assert(ptr, "safe cast failed!");
+  return static_cast<R>(const_cast<T*>(ptr));
+}
+
+template <typename T, typename U>
+struct must_cast_traits {
+  constexpr static BOOL value = false;
+};
+
+template <typename T>
+struct must_cast_traits<T, T> {
+  constexpr static BOOL value = true;
+};
+
+/// @author Amlal El Mahrouss
+/// @brief Safe constexpr cast.
+template <typename T, typename R>
+inline constexpr R* sys_constexpr_cast(T* ptr) {
+  static_assert(must_cast_traits<T, R>::value, "constexpr cast failed! types are mismatching!");
+  return static_cast<R*>(ptr);
+}
+}  // namespace LibSystem::Verify
diff --git a/src/libSystem/docs/SPECIFICATION_SYSCALLS.md b/src/libSystem/docs/SPECIFICATION_SYSCALLS.md
new file mode 100644
index 00000000..89f61498
--- /dev/null
+++ b/src/libSystem/docs/SPECIFICATION_SYSCALLS.md
@@ -0,0 +1,25 @@
+===================================
+# 0: General Information
+===================================
+
+- **Programming Language**: C / C++
+- **Build System**: Make / NeBuild 
+- **Purpose**: System Call Interface (SCI) for NeKernel
+
+===================================
+# 1: How It Works
+===================================
+
+- This header provides the raw API surface for accessing NeKernel's system calls.
+
+- It is **not** directly used by applications.
+    - Instead, it is abstracted by the **SystemSDK**, which presents a stable, high-level interface.
+
+- At runtime:
+    - System calls are routed from user-space code to the **kernel syscall manager**.
+    - The syscall manager executes the requested operation and returns control to `libSystem`.
+    - Finally, the result is delivered back to the originating process.
+
+- This separation ensures that:
+    - The SCI remains low-level and close to the ABI.
+    - `SystemSDK` provides portability and shielding from changes in syscall internals.
+\ No newline at end of file
diff --git a/src/libSystem/libSystem.json b/src/libSystem/libSystem.json
new file mode 100644
index 00000000..9df1b8f0
--- /dev/null
+++ b/src/libSystem/libSystem.json
@@ -0,0 +1,20 @@
+{
+  "compiler_path": "x86_64-w64-mingw32-g++",
+  "compiler_std": "c++20",
+  "headers_path": ["../", "./"],
+  "sources_path": ["src/*.cc", "src/*.stub.obj"],
+  "output_name": "libSystem.dll",
+  "compiler_flags": [
+    "-ffreestanding",
+    "-shared",
+    "-fPIC",
+    "-fno-rtti",
+    "-fno-exceptions",
+    "-Wl,--subsystem=17"
+  ],
+  "cpp_macros": [
+    "kLibSystemVersion=0x0100",
+    "kLibSystemVersionHighest=0x0100",
+    "kLibSystemVersionLowest=0x0100"
+  ]
+}
diff --git a/src/libSystem/obj/.keep b/src/libSystem/obj/.keep
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/libSystem/obj/.keep
diff --git a/src/libSystem/src/JailCalls.cc b/src/libSystem/src/JailCalls.cc
new file mode 100644
index 00000000..f7ca5bec
--- /dev/null
+++ b/src/libSystem/src/JailCalls.cc
@@ -0,0 +1,17 @@
+/* ========================================
+
+  Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#include <libSystem/SystemKit/Err.h>
+#include <libSystem/SystemKit/Jail.h>
+#include <libSystem/SystemKit/Syscall.h>
+#include <libSystem/SystemKit/System.h>
+#include <libSystem/SystemKit/Verify.h>
+
+using namespace LibSystem;
+
+IMPORT_C struct JAIL* JailGetCurrent(Void) {
+  return (struct JAIL*) libsys_syscall_arg_1(SYSCALL_HASH("JailGetCurrent"));
+}
+\ No newline at end of file
diff --git a/src/libSystem/src/Makefile b/src/libSystem/src/Makefile
new file mode 100644
index 00000000..622223b4
--- /dev/null
+++ b/src/libSystem/src/Makefile
@@ -0,0 +1,16 @@
+##################################################
+# (c) Amlal El Mahrouss and NeKernel contributors, licensed under the Apache 2.0 license.
+# This file is for libSystem.dll's syscall stubs.
+##################################################
+
+ASM=nasm
+FLAGS=-f win64
+
+.PHONY: error
+error:
+	@echo "==> Invalid recipe."
+	@echo "==> Use libsys_asm_io_<arch> instead."
+
+.PHONY: libsys_asm_io_x64
+libsys_asm_io_x64:
+	$(ASM) $(FLAGS) SystemCallsABI+AMD64.asm -o SystemCallsABI+AMD64.stub.obj
diff --git a/src/libSystem/src/SystemCalls.cc b/src/libSystem/src/SystemCalls.cc
new file mode 100644
index 00000000..7409c9b7
--- /dev/null
+++ b/src/libSystem/src/SystemCalls.cc
@@ -0,0 +1,169 @@
+/* ========================================
+
+  Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#include <libSystem/SystemKit/Err.h>
+#include <libSystem/SystemKit/Syscall.h>
+#include <libSystem/SystemKit/System.h>
+#include <libSystem/SystemKit/Verify.h>
+
+using namespace LibSystem;
+
+IMPORT_C Char* StrFmt(const Char* fmt, ...) {
+  if (!fmt || *fmt == 0) return const_cast<Char*>("(null)");
+
+  return const_cast<Char*>("");
+}
+
+// memmove-style copy
+IMPORT_C VoidPtr MmCopyMemory(_Input VoidPtr dest, _Input VoidPtr src, _Input SizeT len) {
+  // handles overlap, prefers 64-bit word copies when aligned
+  if (!len || !dest || !src) return nullptr;
+
+  auto s = static_cast<const UInt8*>(src);
+  auto d = static_cast<UInt8*>(dest);
+
+  if (d == s) return dest;
+
+  // decide direction
+  if (d > s && d < s + len) {
+    const UInt8* rs = s + len;
+    UInt8*       rd = d + len;
+
+    // try 64-bit aligned backward copy
+    if (len >= sizeof(UInt64) && (reinterpret_cast<UIntPtr>(rs) % sizeof(UInt64) == 0) &&
+        (reinterpret_cast<UIntPtr>(rd) % sizeof(UInt64) == 0)) {
+      auto rsw = reinterpret_cast<const UInt64*>(rs);
+      auto rdw = reinterpret_cast<UInt64*>(rd);
+
+      SizeT words = len / sizeof(UInt64);
+
+      for (SizeT i = 0; i < words; ++i) {
+        rdw[-1 - static_cast<SizeT>(i)] = rsw[-1 - static_cast<SizeT>(i)];
+      }
+
+      SizeT rem = len % sizeof(UInt64);
+      for (SizeT i = 0; i < rem; ++i) {
+        rd[-1 - i] = rs[-1 - i];
+      }
+    } else {
+      // byte-wise backward
+      for (SizeT i = 0; i < len; ++i) {
+        rd[-1 - i] = rs[-1 - i];
+      }
+    }
+  } else {
+    // try 64-bit aligned forward copy
+    if (len >= sizeof(UInt64) && (reinterpret_cast<UIntPtr>(s) % sizeof(UInt64) == 0) &&
+        (reinterpret_cast<UIntPtr>(d) % sizeof(UInt64) == 0)) {
+      auto  sw    = reinterpret_cast<const UInt64*>(s);
+      auto  dw    = reinterpret_cast<UInt64*>(d);
+      SizeT words = len / sizeof(UInt64);
+
+      for (SizeT i = 0; i < words; ++i) {
+        dw[i] = sw[i];
+      }
+
+      SizeT       rem    = len % sizeof(UInt64);
+      const SizeT offset = words * sizeof(UInt64);
+      for (SizeT i = 0; i < rem; ++i) {
+        d[offset + i] = s[offset + i];
+      }
+    } else {
+      for (SizeT i = 0; i < len; ++i) {
+        d[i] = s[i];
+      }
+    }
+  }
+
+  return dest;
+}
+
+IMPORT_C SInt64 MmStrLen(const Char* in) {
+  // strlen via pointer walk
+  if (!in) return -kErrorInvalidData;
+
+  const Char* p = in;
+  while (*p) ++p;
+
+  return static_cast<SInt64>(p - in);
+}
+
+IMPORT_C VoidPtr MmFillMemory(_Input VoidPtr dest, _Input SizeT len, _Input UInt8 value) {
+  if (!len || !dest) return nullptr;
+
+  auto d = static_cast<UInt8*>(dest);
+
+  if (len >= sizeof(UInt64) && (reinterpret_cast<UIntPtr>(d) % sizeof(UInt64)) == 0) {
+    UInt64 pattern = static_cast<UInt64>(value);
+    pattern |= (pattern << 8);
+    pattern |= (pattern << 16);
+    pattern |= (pattern << 32);
+
+    auto  dw    = reinterpret_cast<UInt64*>(d);
+    SizeT words = len / sizeof(UInt64);
+
+    for (SizeT i = 0; i < words; ++i) {
+      dw[i] = pattern;
+    }
+
+    SizeT       rem    = len % sizeof(UInt64);
+    const SizeT offset = words * sizeof(UInt64);
+    for (SizeT i = 0; i < rem; ++i) {
+      d[offset + i] = value;
+    }
+  } else {
+    for (SizeT i = 0; i < len; ++i) d[i] = value;
+  }
+
+  return dest;
+}
+
+IMPORT_C Ref IoOpenFile(_Input const Char* path, _Input const Char* drv_letter) {
+  return static_cast<Ref>(libsys_syscall_arg_3(
+      SYSCALL_HASH("IoOpenFile"), Verify::sys_safe_cast(path), Verify::sys_safe_cast(drv_letter)));
+}
+
+IMPORT_C Void IoCloseFile(_Input Ref desc) {
+  libsys_syscall_arg_2(SYSCALL_HASH("IoCloseFile"), static_cast<VoidPtr>(desc));
+}
+
+IMPORT_C UInt64 IoSeekFile(_Input Ref desc, _Input UInt64 off) {
+  auto ret_ptr = libsys_syscall_arg_3(SYSCALL_HASH("IoSeekFile"), static_cast<VoidPtr>(desc),
+                                      reinterpret_cast<VoidPtr>(&off));
+
+  if (!ret_ptr) return ~0UL;
+
+  auto   ret    = static_cast<volatile UInt64*>(ret_ptr);
+  UInt64 result = *ret;
+  MUST_PASS(result != ~0UL);
+  return result;
+}
+
+IMPORT_C UInt64 IoTellFile(_Input Ref desc) {
+  auto ret_ptr = libsys_syscall_arg_2(SYSCALL_HASH("IoTellFile"), static_cast<VoidPtr>(desc));
+  if (!ret_ptr) return ~0UL;
+  auto ret = static_cast<volatile UInt64*>(ret_ptr);
+  return *ret;
+}
+
+IMPORT_C SInt32 PrintOut(_Input IORef desc, const Char* fmt, ...) {
+  va_list args;
+  va_start(args, fmt);
+
+  auto buf = StrFmt(fmt, args);
+
+  va_end(args);
+
+  // if truncated, `needed` >= kBufferSz; we still send truncated buffer
+  auto ret_ptr = libsys_syscall_arg_3(SYSCALL_HASH("PrintOut"), static_cast<VoidPtr>(desc),
+                                      Verify::sys_safe_cast(buf));
+
+  if (!ret_ptr) return -kErrorInvalidData;
+
+  auto ret = static_cast<const volatile SInt32*>(ret_ptr);
+
+  return *ret;
+}
diff --git a/src/libSystem/src/SystemCallsABI+AMD64.asm b/src/libSystem/src/SystemCallsABI+AMD64.asm
new file mode 100644
index 00000000..dd8fc9e8
--- /dev/null
+++ b/src/libSystem/src/SystemCallsABI+AMD64.asm
@@ -0,0 +1,81 @@
+;; /*
+;; *	========================================================
+;; *
+;; *	libSystem/src/SystemCallsABI+AMD64.asm
+;; * 	Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+;; *
+;; * 	========================================================
+;; */
+
+[bits 64]
+
+section .text
+
+global libsys_syscall_arg_1
+global libsys_syscall_arg_2
+global libsys_syscall_arg_3
+global libsys_syscall_arg_4
+
+libsys_syscall_arg_1:
+    push rbp
+    mov rbp, rsp
+
+    mov r8, rcx
+
+    xor rax, rax
+
+    syscall
+
+    pop rbp
+
+    ret
+
+libsys_syscall_arg_2:
+    push rbp
+    mov rbp, rsp
+
+    mov r8, rcx
+    mov r9, rdx
+
+    xor rax, rax
+
+    syscall
+
+    pop rbp
+
+    ret
+
+libsys_syscall_arg_3:
+    push rbp
+    mov rbp, rsp
+
+    mov r8, rcx
+    mov r9, rdx
+    mov r10, rbx
+
+    xor rax, rax
+
+    syscall
+
+    pop rbp
+
+    ret
+
+libsys_syscall_arg_4:
+    push rbp
+    mov rbp, rsp
+
+    mov rax, r8
+
+    mov r8, rcx
+    mov r9, rdx
+    mov r10, rbx
+    mov r11, rax
+
+    xor rax, rax
+
+    syscall
+
+    pop rbp
+
+    ret
diff --git a/src/libSystem/src/Utils.cc b/src/libSystem/src/Utils.cc
new file mode 100644
index 00000000..9d0920e0
--- /dev/null
+++ b/src/libSystem/src/Utils.cc
@@ -0,0 +1,29 @@
+/* ========================================
+
+  Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#include <libSystem/SystemKit/Err.h>
+#include <libSystem/SystemKit/Syscall.h>
+#include <libSystem/SystemKit/System.h>
+#include <libSystem/SystemKit/Verify.h>
+
+using namespace LibSystem;
+
+/// @note This uses the FNV 64-bit variant.
+IMPORT_C UInt64 libsys_hash_64(const Char* path) {
+  if (!path || *path == 0) return 0;
+
+  const UInt64 kFNVSeed  = 0xcbf29ce484222325ULL;
+  const UInt64 kFNVPrime = 0x100000001b3ULL;
+
+  UInt64 hash = kFNVSeed;
+
+  while (*path) {
+    hash ^= (Char) (*path++);
+    hash *= kFNVPrime;
+  }
+
+  return hash;
+}
diff --git a/src/libSystem/src/VerifyCalls.cc b/src/libSystem/src/VerifyCalls.cc
new file mode 100644
index 00000000..1c00612f
--- /dev/null
+++ b/src/libSystem/src/VerifyCalls.cc
@@ -0,0 +1,18 @@
+/* ========================================
+
+  Copyright (C) 2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#include <libSystem/SystemKit/Err.h>
+#include <libSystem/SystemKit/Syscall.h>
+#include <libSystem/SystemKit/Verify.h>
+
+using namespace LibSystem;
+
+IMPORT_C Void _rtl_assert(Bool expr, const Char* origin) {
+  if (!expr) {
+    PrintOut(nullptr, "Assertion failed: %s\r", origin);
+    libsys_syscall_arg_1(SYSCALL_HASH("_rtl_debug_break"));
+  }
+}
+\ No newline at end of file