feat(userspace): shell runs programs (ls, cat) via spawn w/ terminal+storage+args page; ext4 holes read as zeros; storage re-attach same buffer

crates/servers/storage-server/src/tests/ext4_real.rs

@@ -170,3 +170,16 @@ fn one_read_fills_the_buffer_across_blocks() {
     assert_eq!(fs.read(h, &mut buf), Some(total - 10_000));
     assert_eq!(fs.read(h, &mut buf), Some(0));
 }
+
+#[test]
+fn holes_read_as_zeros() {
+    let dir = scratch("sparse");
+    // Data, then a zero block mkfs stores as a hole, then data again.
+    let mut data = std::vec![b'x'; 4096];
+    data.extend(std::vec![0u8; 4096]);
+    data.extend(b"end");
+    std::fs::write(dir.join("root/sparse.bin"), &data).unwrap();
+    let Some(img) = mkfs(&dir, MKFS_FEATURES) else { return };
+    let mut fs = Ext4::mount(FileDisk(img)).expect("mount");
+    assert_eq!(read_all(&mut fs, b"sparse.bin"), data);
+}

crates/servers/storage-server/src/tests/server.rs

@@ -67,10 +67,14 @@ fn nothing_works_before_attaching() {
 }
 
 #[test]
-fn a_client_attaches_once() {
+fn attaching_again_hands_back_the_same_buffer() {
     let mut s = server();
-    Client::attach(&mut s, 0);
-    assert_eq!(call(&mut s, 0, StorageRequest::Attach).0, StorageResponse::Error);
+    let (first, cap) = call(&mut s, 0, StorageRequest::Attach);
+    assert_eq!(call(&mut s, 0, StorageRequest::Attach), (first, cap));
+    // Not a new client: the other seven places are still free.
+    for badge in 1..8 {
+        assert!(matches!(call(&mut s, badge, StorageRequest::Attach).0, StorageResponse::Attached { .. }));
+    }
 }
 
 #[test]