Struct UserMut

pub struct UserMut<'a, T: Sized, R: Copy + ReprMut<T> = *mut T> { /* private fields */ }

A pointer to mutable userspace memory with a defined in-memory representation.

This exists primarily for use in defining safe ioctl/etc request types, to ensure that only valid addresses can be assigned to a field from safe Rust. Using this is important for any pointer that the kernel might write through, to ensure that safe Rust cannot assign an address that might cause the kernel to corrupt memory.

If a struct type used with an ioctl request has a field containing an address that the kernel might write to then defining that field as a UserPtr ensures that it can only have a valid address assigned to it unless the caller uses the unsafe Self::from_ptr.

The in-memory representation of this type is guaranteed to match that of type parameter R, which defaults to being a pointer to T.

Implementations

impl<'a, T: Sized, R: Copy + ReprMut<T>> UserMut<'a, T, R>

pub unsafe fn from_ptr(ptr: *mut T) -> Self

Create a representation of the given pointer.

Safety

The pointer must remain valid for the lifetime of the result.

pub fn from_ref(r: &'a mut T) -> Self

Create a representation of a pointer referring to the same object as the given reference.

pub fn repr(&self) -> R

Get the in-memory representation of the pointer.