refactor: add website code

kernel/src/Api/UserMemory.hpp

@@ -0,0 +1,68 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+#include <Sched/Scheduler.hpp>
+#include <Memory/Paging.hpp>
+
+namespace Montauk::UserMemory {
+
+    static constexpr uint64_t USER_SPACE_END = 0x0000800000000000ULL;
+
+    inline bool IsUserPtr(uint64_t addr) {
+        return addr == 0 || addr < USER_SPACE_END;
+    }
+
+    inline bool ValidUserPtr(uint64_t addr) {
+        return addr != 0 && addr < USER_SPACE_END;
+    }
+
+    inline uint64_t CurrentPml4() {
+        auto* proc = Sched::GetCurrentProcessPtr();
+        return proc ? proc->pml4Phys : 0;
+    }
+
+    inline bool Range(uint64_t addr, uint64_t size, bool requireWrite = false) {
+        if (size == 0) return true;
+        if (!ValidUserPtr(addr)) return false;
+        if (addr + size < addr) return false;
+        if (addr + size > USER_SPACE_END) return false;
+
+        uint64_t pml4Phys = CurrentPml4();
+        if (pml4Phys == 0) return false;
+
+        return Memory::VMM::Paging::IsUserRangeAccessible(pml4Phys, addr, size, requireWrite);
+    }
+
+    inline bool OptionalRange(uint64_t addr, uint64_t size, bool requireWrite = false) {
+        return addr == 0 || Range(addr, size, requireWrite);
+    }
+
+    template<typename T>
+    inline bool Readable(uint64_t addr) {
+        return Range(addr, sizeof(T), false);
+    }
+
+    template<typename T>
+    inline bool Writable(uint64_t addr) {
+        return Range(addr, sizeof(T), true);
+    }
+
+    inline bool String(uint64_t addr, uint64_t maxLen) {
+        if (!ValidUserPtr(addr) || maxLen == 0) return false;
+
+        uint64_t pml4Phys = CurrentPml4();
+        if (pml4Phys == 0) return false;
+
+        const char* str = (const char*)addr;
+        for (uint64_t i = 0; i < maxLen; i++) {
+            if (!Memory::VMM::Paging::IsUserRangeAccessible(pml4Phys, addr + i, 1, false)) {
+                return false;
+            }
+            if (str[i] == '\0') return true;
+        }
+
+        return false;
+    }
+}