Support reading context status.

src/scheme/proc.rs

@@ -1155,6 +1155,18 @@ impl ContextHandle {
                 buf.copy_exactly(crate::cpu_set::mask_as_bytes(&mask))?;
                 Ok(mem::size_of_val(&mask))
             } // TODO: Replace write() with SYS_SENDFD?
+            ContextHandle::Status => {
+                let status = match context.read().status {
+                    Status::Runnable => ContextStatus::Runnable,
+                    Status::Blocked => ContextStatus::Blocked,
+                    Status::Dead => ContextStatus::Dead,
+                    Status::HardBlocked {
+                        reason: HardBlockedReason::NotYetStarted,
+                    } => ContextStatus::NotYetStarted,
+                    _ => ContextStatus::Other,
+                };
+                buf.copy_common_bytes_from_slice(&(status as usize).to_ne_bytes())
+            }
             ContextHandle::Attr => {
                 let (euid, egid, ens, pid) = match context.read() {
                     ref c => (c.euid, c.egid, c.ens.get() as u32, c.pid as u32),