[Yellowstone] Wireframe for moving yellowstone to rust.

rust/lib/mammoth/src/sync.rs

@@ -0,0 +1,19 @@
+use crate::{cap::Capability, syscall, zion::ZError};
+
+pub struct Semaphore {
+    cap: Capability,
+}
+
+impl Semaphore {
+    pub fn new() -> Result<Self, ZError> {
+        syscall::semaphore_create().map(|cap| Self { cap })
+    }
+
+    pub fn wait(&self) -> Result<(), ZError> {
+        syscall::semaphone_wait(&self.cap)
+    }
+
+    pub fn signal(&self) -> Result<(), ZError> {
+        syscall::semaphone_signal(&self.cap)
+    }
+}