Unsafe Rust in TuskLang

⚠️ Unsafe Foundation

Unsafe Rust provides the ability to bypass Rust's safety guarantees when necessary, enabling low-level programming, FFI integration, and performance optimizations. This guide covers raw pointers, unsafe blocks, and safe abstractions over unsafe code.

🏗️ Unsafe Architecture

Unsafe Principles

[unsafe_principles]
safety_contracts: true
unsafe_blocks: true
raw_pointers: true
ffi_integration: true
[unsafe_patterns]
safe_abstractions: true
unsafe_apis: true
memory_safety: true
undefined_behavior: true

Unsafe Components

[unsafe_components]
raw_pointers: "unsafe"
unsafe_functions: "unsafe_blocks"
ffi: "foreign_functions"
static_mut: "global_state"

🔧 Raw Pointers

Raw Pointer Types

[raw_pointer_types]
const_pointers: true
mut_pointers: true
pointer_arithmetic: true
[raw_pointer_implementation]
// Raw pointer basics
pub fn raw_pointer_example() {
    let mut x = 5;
    let raw_ptr = &mut x as *mut i32;
    
    unsafe {
        println!("Value through raw pointer: {}", *raw_ptr);
        *raw_ptr = 10;
        println!("Modified value: {}", *raw_ptr);
    }
}
// Raw pointer arithmetic
pub fn pointer_arithmetic_example() {
    let mut arr = [1, 2, 3, 4, 5];
    let ptr = arr.as_mut_ptr();
    
    unsafe {
        for i in 0..5 {
            let element_ptr = ptr.add(i);
            println!("Element {}: {}", i, *element_ptr);
        }
    }
}
// Null pointers
pub fn null_pointer_example() {
    let null_ptr: *const i32 = std::ptr::null();
    
    unsafe {
        if null_ptr.is_null() {
            println!("Pointer is null");
        } else {
            println!("Pointer is not null: {}", *null_ptr);
        }
    }
}
// Raw pointer to struct
#[derive(Debug)]
pub struct Point {
    x: f64,
    y: f64,
}
pub fn struct_pointer_example() {
    let mut point = Point { x: 1.0, y: 2.0 };
    let ptr = &mut point as *mut Point;
    
    unsafe {
        println!("Point: {:?}", *ptr);
        (*ptr).x = 3.0;
        (*ptr).y = 4.0;
        println!("Modified point: {:?}", *ptr);
    }
}

Pointer Safety

[pointer_safety]
dereference_safety: true
aliasing_rules: true
lifetime_management: true
[pointer_safety_implementation]
// Safe dereferencing
pub fn safe_dereference_example() {
    let mut data = vec![1, 2, 3, 4, 5];
    let ptr = data.as_mut_ptr();
    
    unsafe {
        // Safe because we know the pointer is valid
        for i in 0..data.len() {
            let element_ptr = ptr.add(i);
            println!("Element {}: {}", i, *element_ptr);
        }
    }
}
// Aliasing prevention
pub fn aliasing_example() {
    let mut data = vec![1, 2, 3, 4, 5];
    let ptr1 = data.as_mut_ptr();
    let ptr2 = data.as_mut_ptr();
    
    unsafe {
        // This is safe because we're not aliasing mutable references
        *ptr1 = 10;
        *ptr2 = 20;
    }
}
// Lifetime management with raw pointers
pub struct RawBuffer {
    ptr: *mut u8,
    len: usize,
}
impl RawBuffer {
    pub fn new(size: usize) -> Self {
        let layout = std::alloc::Layout::from_size_align(size, 8).unwrap();
        let ptr = unsafe { std::alloc::alloc(layout) };
        
        Self {
            ptr,
            len: size,
        }
    }
    
    pub fn as_slice(&self) -> &[u8] {
        unsafe {
            std::slice::from_raw_parts(self.ptr, self.len)
        }
    }
    
    pub fn as_mut_slice(&mut self) -> &mut [u8] {
        unsafe {
            std::slice::from_raw_parts_mut(self.ptr, self.len)
        }
    }
}
impl Drop for RawBuffer {
    fn drop(&mut self) {
        let layout = std::alloc::Layout::from_size_align(self.len, 8).unwrap();
        unsafe {
            std::alloc::dealloc(self.ptr, layout);
        }
    }
}

🔄 Unsafe Functions

Unsafe Function Design

[unsafe_function_design]
safety_contracts: true
documentation: true
invariant_checks: true
[unsafe_function_implementation]
// Unsafe function with safety contract
/// # Safety
/// 
/// The caller must ensure that:
/// - ptr is not null
/// - ptr points to valid memory
/// - ptr is aligned for T
/// - ptr is valid for reads
pub unsafe fn read_value<T>(ptr: *const T) -> T {
    // Safety: caller guarantees ptr is valid
    ptr.read()
}
// Unsafe function with runtime checks
pub fn safe_read_value<T>(ptr: *const T) -> Option<T> {
    if ptr.is_null() {
        return None;
    }
    
    unsafe {
        Some(ptr.read())
    }
}
// Unsafe function with invariant checking
pub struct SafeArray<T> {
    ptr: *mut T,
    len: usize,
}
impl<T> SafeArray<T> {
    pub fn new(len: usize) -> Self {
        let layout = std::alloc::Layout::array::<T>(len).unwrap();
        let ptr = unsafe { std::alloc::alloc(layout) as *mut T };
        
        Self { ptr, len }
    }
    
    /// # Safety
    /// 
    /// The caller must ensure that:
    /// - index < self.len
    pub unsafe fn get_unchecked(&self, index: usize) -> &T {
        &*self.ptr.add(index)
    }
    
    /// # Safety
    /// 
    /// The caller must ensure that:
    /// - index < self.len
    pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T {
        &mut *self.ptr.add(index)
    }
    
    // Safe wrapper
    pub fn get(&self, index: usize) -> Option<&T> {
        if index < self.len {
            unsafe { Some(self.get_unchecked(index)) }
        } else {
            None
        }
    }
    
    pub fn get_mut(&mut self, index: usize) -> Option<&mut T> {
        if index < self.len {
            unsafe { Some(self.get_unchecked_mut(index)) }
        } else {
            None
        }
    }
}
impl<T> Drop for SafeArray<T> {
    fn drop(&mut self) {
        let layout = std::alloc::Layout::array::<T>(self.len).unwrap();
        unsafe {
            std::alloc::dealloc(self.ptr as *mut u8, layout);
        }
    }
}

Unsafe Traits

[unsafe_traits]
send_sync: true
unsafe_trait_impl: true
safety_guarantees: true
[unsafe_trait_implementation]
// Unsafe trait
pub unsafe trait UnsafeTrait {
    fn unsafe_method(&self);
}
// Safe wrapper trait
pub trait SafeTrait {
    fn safe_method(&self);
}
// Implementation of unsafe trait
pub struct UnsafeStruct {
    data: *mut i32,
}
unsafe impl UnsafeTrait for UnsafeStruct {
    fn unsafe_method(&self) {
        unsafe {
            if !self.data.is_null() {
                println!("Unsafe value: {}", *self.data);
            }
        }
    }
}
// Safe implementation
impl SafeTrait for UnsafeStruct {
    fn safe_method(&self) {
        // Safe wrapper around unsafe code
        if !self.data.is_null() {
            unsafe {
                println!("Safe access: {}", *self.data);
            }
        }
    }
}
// Send and Sync implementations
unsafe impl Send for UnsafeStruct {}
unsafe impl Sync for UnsafeStruct {}

🌐 FFI Integration

C FFI

[ffi_integration]
c_functions: true
c_structs: true
callback_functions: true
[ffi_implementation]
use std::ffi::{c_char, CStr, CString};
// C function declarations
#[link(name = "c")]
extern "C" {
    fn strlen(s: *const c_char) -> usize;
    fn printf(format: *const c_char, ...) -> i32;
}
// Safe wrapper for C functions
pub fn safe_strlen(s: &str) -> usize {
    let c_string = CString::new(s).unwrap();
    unsafe {
        strlen(c_string.as_ptr())
    }
}
pub fn safe_printf(format: &str) {
    let c_format = CString::new(format).unwrap();
    unsafe {
        printf(c_format.as_ptr());
    }
}
// C struct integration
#[repr(C)]
pub struct CPoint {
    x: f64,
    y: f64,
}
#[link(name = "math")]
extern "C" {
    fn distance(p1: const CPoint, p2: const CPoint) -> f64;
}
pub fn safe_distance(p1: &CPoint, p2: &CPoint) -> f64 {
    unsafe {
        distance(p1, p2)
    }
}
// Callback functions
pub type CallbackFn = extern "C" fn(i32) -> i32;
#[link(name = "callback")]
extern "C" {
    fn register_callback(callback: CallbackFn);
    fn call_callback(value: i32) -> i32;
}
pub extern "C" fn rust_callback(value: i32) -> i32 {
    value * 2
}
pub fn register_rust_callback() {
    unsafe {
        register_callback(rust_callback);
    }
}
pub fn call_rust_callback(value: i32) -> i32 {
    unsafe {
        call_callback(value)
    }
}

System Calls

[system_calls]
syscalls: true
low_level_io: true
memory_mapping: true
[system_calls_implementation]
use std::os::unix::io::{AsRawFd, RawFd};
// Low-level file operations
pub struct LowLevelFile {
    fd: RawFd,
}
impl LowLevelFile {
    pub fn open(path: &str, flags: i32, mode: u32) -> Result<Self, i32> {
        let c_path = CString::new(path).unwrap();
        let fd = unsafe {
            libc::open(c_path.as_ptr(), flags, mode)
        };
        
        if fd == -1 {
            Err(std::io::Error::last_os_error().raw_os_error().unwrap())
        } else {
            Ok(Self { fd })
        }
    }
    
    pub fn read(&self, buffer: &mut [u8]) -> Result<usize, i32> {
        let result = unsafe {
            libc::read(
                self.fd,
                buffer.as_mut_ptr() as *mut libc::c_void,
                buffer.len(),
            )
        };
        
        if result == -1 {
            Err(std::io::Error::last_os_error().raw_os_error().unwrap())
        } else {
            Ok(result as usize)
        }
    }
    
    pub fn write(&self, buffer: &[u8]) -> Result<usize, i32> {
        let result = unsafe {
            libc::write(
                self.fd,
                buffer.as_ptr() as *const libc::c_void,
                buffer.len(),
            )
        };
        
        if result == -1 {
            Err(std::io::Error::last_os_error().raw_os_error().unwrap())
        } else {
            Ok(result as usize)
        }
    }
}
impl Drop for LowLevelFile {
    fn drop(&mut self) {
        unsafe {
            libc::close(self.fd);
        }
    }
}
// Memory mapping
pub struct MemoryMap {
    ptr: *mut u8,
    len: usize,
}
impl MemoryMap {
    pub fn new(fd: RawFd, len: usize, offset: i64) -> Result<Self, i32> {
        let ptr = unsafe {
            libc::mmap(
                std::ptr::null_mut(),
                len,
                libc::PROT_READ | libc::PROT_WRITE,
                libc::MAP_SHARED,
                fd,
                offset,
            ) as *mut u8
        };
        
        if ptr == std::ptr::null_mut() {
            Err(std::io::Error::last_os_error().raw_os_error().unwrap())
        } else {
            Ok(Self { ptr, len })
        }
    }
    
    pub fn as_slice(&self) -> &[u8] {
        unsafe {
            std::slice::from_raw_parts(self.ptr, self.len)
        }
    }
    
    pub fn as_mut_slice(&mut self) -> &mut [u8] {
        unsafe {
            std::slice::from_raw_parts_mut(self.ptr, self.len)
        }
    }
}
impl Drop for MemoryMap {
    fn drop(&mut self) {
        unsafe {
            libc::munmap(self.ptr as *mut libc::c_void, self.len);
        }
    }
}

🔒 Static Mutable State

Global State Management

[global_state]
static_mut: true
thread_local: true
atomic_operations: true
[global_state_implementation]
use std::sync::atomic::{AtomicUsize, Ordering};
use std::cell::UnsafeCell;
// Static mutable variable
static mut GLOBAL_COUNTER: usize = 0;
pub fn increment_global_counter() {
    unsafe {
        GLOBAL_COUNTER += 1;
    }
}
pub fn get_global_counter() -> usize {
    unsafe {
        GLOBAL_COUNTER
    }
}
// Thread-local storage
thread_local! {
    static THREAD_COUNTER: UnsafeCell<usize> = UnsafeCell::new(0);
}
pub fn increment_thread_counter() {
    THREAD_COUNTER.with(|counter| {
        unsafe {
            *counter.get() += 1;
        }
    });
}
pub fn get_thread_counter() -> usize {
    THREAD_COUNTER.with(|counter| {
        unsafe {
            *counter.get()
        }
    })
}
// Atomic global state
static ATOMIC_COUNTER: AtomicUsize = AtomicUsize::new(0);
pub fn increment_atomic_counter() {
    ATOMIC_COUNTER.fetch_add(1, Ordering::SeqCst);
}
pub fn get_atomic_counter() -> usize {
    ATOMIC_COUNTER.load(Ordering::SeqCst)
}
// Singleton pattern with unsafe
pub struct Singleton {
    data: UnsafeCell<String>,
}
impl Singleton {
    pub fn new() -> Self {
        Self {
            data: UnsafeCell::new(String::new()),
        }
    }
    
    pub fn set_data(&self, data: String) {
        unsafe {
            *self.data.get() = data;
        }
    }
    
    pub fn get_data(&self) -> String {
        unsafe {
            (*self.data.get()).clone()
        }
    }
}
unsafe impl Send for Singleton {}
unsafe impl Sync for Singleton {}
static mut SINGLETON: Option<Singleton> = None;
pub fn get_singleton() -> &'static Singleton {
    unsafe {
        if SINGLETON.is_none() {
            SINGLETON = Some(Singleton::new());
        }
        SINGLETON.as_ref().unwrap()
    }
}

🔄 Safe Abstractions

Wrapping Unsafe Code

[safe_abstractions]
unsafe_wrappers: true
type_safety: true
error_handling: true
[safe_abstractions_implementation]
// Safe wrapper around raw pointer
pub struct SafePtr<T> {
    ptr: *mut T,
    len: usize,
}
impl<T> SafePtr<T> {
    pub fn new(len: usize) -> Self {
        let layout = std::alloc::Layout::array::<T>(len).unwrap();
        let ptr = unsafe { std::alloc::alloc(layout) as *mut T };
        
        Self { ptr, len }
    }
    
    pub fn len(&self) -> usize {
        self.len
    }
    
    pub fn is_empty(&self) -> bool {
        self.len == 0
    }
    
    pub fn get(&self, index: usize) -> Option<&T> {
        if index < self.len {
            unsafe {
                Some(&*self.ptr.add(index))
            }
        } else {
            None
        }
    }
    
    pub fn get_mut(&mut self, index: usize) -> Option<&mut T> {
        if index < self.len {
            unsafe {
                Some(&mut *self.ptr.add(index))
            }
        } else {
            None
        }
    }
    
    pub fn iter(&self) -> SafePtrIter<T> {
        SafePtrIter {
            ptr: self.ptr,
            len: self.len,
            index: 0,
        }
    }
}
impl<T> Drop for SafePtr<T> {
    fn drop(&mut self) {
        let layout = std::alloc::Layout::array::<T>(self.len).unwrap();
        unsafe {
            std::alloc::dealloc(self.ptr as *mut u8, layout);
        }
    }
}
pub struct SafePtrIter<T> {
    ptr: *mut T,
    len: usize,
    index: usize,
}
impl<T> Iterator for SafePtrIter<T> {
    type Item = &'static T;
    
    fn next(&mut self) -> Option<Self::Item> {
        if self.index < self.len {
            let item = unsafe { &*self.ptr.add(self.index) };
            self.index += 1;
            Some(item)
        } else {
            None
        }
    }
}
// Safe wrapper for FFI
pub struct SafeCString {
    inner: CString,
}
impl SafeCString {
    pub fn new(s: &str) -> Result<Self, std::ffi::NulError> {
        Ok(Self {
            inner: CString::new(s)?,
        })
    }
    
    pub fn as_ptr(&self) -> *const c_char {
        self.inner.as_ptr()
    }
    
    pub fn to_string_lossy(&self) -> std::borrow::Cow<str> {
        self.inner.to_string_lossy()
    }
}
// Safe wrapper for system calls
pub struct SafeFile {
    inner: LowLevelFile,
}
impl SafeFile {
    pub fn open(path: &str) -> Result<Self, std::io::Error> {
        let file = LowLevelFile::open(path, libc::O_RDWR | libc::O_CREAT, 0o644)
            .map_err(|e| std::io::Error::from_raw_os_error(e))?;
        
        Ok(Self { inner: file })
    }
    
    pub fn read(&self, buffer: &mut [u8]) -> Result<usize, std::io::Error> {
        self.inner.read(buffer)
            .map_err(|e| std::io::Error::from_raw_os_error(e))
    }
    
    pub fn write(&self, buffer: &[u8]) -> Result<usize, std::io::Error> {
        self.inner.write(buffer)
            .map_err(|e| std::io::Error::from_raw_os_error(e))
    }
}

🎯 Best Practices

1. Safety Contracts

- Document all safety requirements - Use runtime checks when possible - Provide safe wrappers - Test unsafe code thoroughly

2. Memory Safety

- Validate all pointers - Check bounds before access - Use proper alignment - Avoid undefined behavior

3. FFI Safety

- Validate C function contracts - Handle null pointers - Manage memory properly - Use proper calling conventions

4. Error Handling

- Return Result types - Provide meaningful errors - Handle edge cases - Use proper error propagation

5. Testing

- Test unsafe code extensively - Use Miri for validation - Test edge cases - Verify safety contracts

Unsafe Rust in TuskLang provides the power to write low-level code while maintaining the ability to create safe abstractions that leverage Rust's safety guarantees.