From c9f97e7ac1178bd7fba5b0ccd59aa1256900f4c2 Mon Sep 17 00:00:00 2001
From: Amlal El Mahrouss <amlal@nekernel.org>
Date: Thu, 11 Sep 2025 17:51:50 +0200
Subject: feat: libSystem: `Verify.h` include file, used to verify SCI's input
 and data.

Signed-off-by: Amlal El Mahrouss <amlal@nekernel.org>
---
 dev/libSystem/SystemKit/Verify.h | 40 ++++++++++++++++++++++++++++++++++++++++
 dev/libSystem/src/System.cc      | 16 +++++-----------
 2 files changed, 45 insertions(+), 11 deletions(-)
 create mode 100644 dev/libSystem/SystemKit/Verify.h

(limited to 'dev/libSystem')

diff --git a/dev/libSystem/SystemKit/Verify.h b/dev/libSystem/SystemKit/Verify.h
new file mode 100644
index 00000000..68e75d47
--- /dev/null
+++ b/dev/libSystem/SystemKit/Verify.h
@@ -0,0 +1,40 @@
+/* -------------------------------------------
+
+   Copyright (C) 2025, Amlal El Mahrouss, all rights reserved.
+
+   File: Verify.h
+   Purpose: System Call Interface Verification Layer.
+
+   ------------------------------------------- */
+
+#pragma once
+
+#include <libSystem/SystemKit/System.h>
+
+namespace LibSystem::Detail {
+/// @author 0xf00sec, and Amlal El Mahrouss
+/// @brief safe cast operator.
+template <typename T, typename R = VoidPtr>
+static 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>
+constexpr R* sys_constexpr_cast(T* ptr) {
+  static_assert(must_cast_traits<T, R>::value, "constexpr cast failed! types are a mismatch!");
+  return static_cast<R*>(ptr);
+}
+}  // namespace LibSystem::Detail
diff --git a/dev/libSystem/src/System.cc b/dev/libSystem/src/System.cc
index 2215c4d8..da9931fe 100644
--- a/dev/libSystem/src/System.cc
+++ b/dev/libSystem/src/System.cc
@@ -7,14 +7,9 @@
 #include <libSystem/SystemKit/Err.h>
 #include <libSystem/SystemKit/Syscall.h>
 #include <libSystem/SystemKit/System.h>
+#include <libSystem/SystemKit/Verify.h>
 
-namespace Detail {
-template <typename T>
-static VoidPtr safe_void_cast(const T* ptr) {
-  _rtl_assert(ptr, "safe void cast failed!");
-  return static_cast<VoidPtr>(const_cast<T*>(ptr));
-}
-}  // namespace Detail
+using namespace LibSystem;
 
 IMPORT_C Void _rtl_assert(Bool expr, const Char* origin) {
   if (!expr) {
@@ -151,9 +146,8 @@ IMPORT_C VoidPtr MmFillMemory(_Input VoidPtr dest, _Input SizeT len, _Input UInt
 }
 
 IMPORT_C Ref IoOpenFile(_Input const Char* path, _Input const Char* drv_letter) {
-  return static_cast<Ref>(libsys_syscall_arg_3(SYSCALL_HASH("IoOpenFile"),
-                                               Detail::safe_void_cast(path),
-                                               Detail::safe_void_cast(drv_letter)));
+  return static_cast<Ref>(libsys_syscall_arg_3(
+      SYSCALL_HASH("IoOpenFile"), Detail::sys_safe_cast(path), Detail::sys_safe_cast(drv_letter)));
 }
 
 IMPORT_C Void IoCloseFile(_Input Ref desc) {
@@ -189,7 +183,7 @@ IMPORT_C SInt32 PrintOut(_Input IORef desc, const Char* fmt, ...) {
 
   // if truncated, `needed` >= kBufferSz; we still send truncated buffer
   auto ret_ptr = libsys_syscall_arg_3(SYSCALL_HASH("PrintOut"), static_cast<VoidPtr>(desc),
-                                      Detail::safe_void_cast(buf));
+                                      Detail::sys_safe_cast(buf));
 
   if (!ret_ptr) return -kErrorInvalidData;
 
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