diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/types.rs | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs index 72710b7442a3..411655eca3e9 100644 --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -2,6 +2,7 @@ //! Kernel types. +use alloc::boxed::Box; use core::{ cell::UnsafeCell, mem::MaybeUninit, @@ -62,6 +63,28 @@ pub trait ForeignOwnable: Sized { unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self; } +impl<T: 'static> ForeignOwnable for Box<T> { + type Borrowed<'a> = &'a T; + + fn into_foreign(self) -> *const core::ffi::c_void { + Box::into_raw(self) as _ + } + + unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T { + // SAFETY: The safety requirements for this function ensure that the object is still alive, + // so it is safe to dereference the raw pointer. + // The safety requirements of `from_foreign` also ensure that the object remains alive for + // the lifetime of the returned value. + unsafe { &*ptr.cast() } + } + + unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self { + // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous + // call to `Self::into_foreign`. + unsafe { Box::from_raw(ptr as _) } + } +} + /// Runs a cleanup function/closure when dropped. /// /// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running. |