Adds Uio::read

Author: ultimaweapon

kernel-1100/src/uio.rs

@@ -33,4 +33,22 @@ impl okf::uio::Uio<Kernel> for Uio {
             td,
         })
     }
+
+    unsafe fn read(td: *mut Thread, iov: *mut IoVec) -> Option<Self> {
+        let res = (*iov).len;
+
+        if res > Self::io_max() {
+            return None;
+        }
+
+        Some(Self {
+            iov,
+            len: 1,
+            off: 0,
+            res: res.try_into().unwrap(),
+            seg: UioSeg::Kernel,
+            op: UioRw::Read,
+            td,
+        })
+    }
 }

src/uio/mod.rs

@@ -9,6 +9,13 @@ pub trait Uio<K: Kernel>: Sized {
     /// - `iov` cannot be null.
     unsafe fn write(td: *mut K::Thread, iov: *mut IoVec) -> Option<Self>;
 
+    /// Returns [`None`] if [`IoVec::len`] of `iov` is greater than [`Uio::io_max()`].
+    ///
+    /// # Safety
+    /// - `td` cannot be null.
+    /// - `iov` cannot be null.
+    unsafe fn read(td: *mut K::Thread, iov: *mut IoVec) -> Option<Self>;
+
     /// Returns value of `UIO_MAXIOV`.
     fn vec_max() -> usize {
         1024