feat(userspace): log server sole console holder; init boots from manifest; adapter loads only init+storage

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

@@ -23,6 +23,8 @@ pub enum StorageRequest {
     Create { path_len: usize },
     Delete { path_len: usize },
     Mkdir { path_len: usize },
+    /// Carries the endpoint to print to.
+    SetLog,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -61,6 +63,7 @@ impl Encode for StorageRequest {
             Create { path_len } => [op::CREATE, path_len, 0, 0],
             Delete { path_len } => [op::DELETE, path_len, 0, 0],
             Mkdir { path_len } => [op::MKDIR, path_len, 0, 0],
+            SetLog => [op::SET_LOG, 0, 0, 0],
         }
     }
 }
@@ -79,6 +82,7 @@ impl Decode for StorageRequest {
             op::CREATE => Create { path_len: w[1] },
             op::DELETE => Delete { path_len: w[1] },
             op::MKDIR => Mkdir { path_len: w[1] },
+            op::SET_LOG => SetLog,
             _ => return None,
         })
     }

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

@@ -31,6 +31,7 @@ pub struct StorageServer<F: FileSystem, B: Buffers> {
     clients: [Option<Client>; MAX_CLIENTS],
     /// The badge of the client that opened each handle.
     owners: [Option<usize>; MAX_HANDLES],
+    log: Option<CapSlot>,
 }
 
 impl<F: FileSystem, B: Buffers> StorageServer<F, B> {
@@ -40,6 +41,26 @@ impl<F: FileSystem, B: Buffers> StorageServer<F, B> {
             buffers,
             clients: [const { None }; MAX_CLIENTS],
             owners: [None; MAX_HANDLES],
+            log: None,
+        }
+    }
+
+    /// Where this server prints, once init has said.
+    pub fn log(&self) -> Option<CapSlot> {
+        self.log
+    }
+
+    /// Clients hold badged copies of the endpoint, so the unbadged sender is
+    /// whoever was given the endpoint itself: init.
+    fn set_log(&mut self, badge: usize, cap: Option<CapSlot>) -> StorageResponse {
+        match (badge, cap, self.log) {
+            (0, Some(cap), None) => {
+                self.log = Some(cap);
+                libkos::start::set_log(Some(cap));
+                libkos::println!("storage: printing through the log server");
+                StorageResponse::Ok
+            }
+            _ => StorageResponse::Error,
         }
     }
 
@@ -117,7 +138,7 @@ impl<F: FileSystem, B: Buffers> StorageServer<F, B> {
             None => R::NotFound,
         };
         let response = match request {
-            Attach => R::Error,
+            Attach | SetLog => R::Error,
             Open { path_len } => {
                 let h = fs.open(&buf[path(path_len)]);
                 opened(owners, h)
@@ -195,9 +216,10 @@ impl<F: FileSystem, B: Buffers> Server for StorageServer<F, B> {
         &mut self,
         badge: usize,
         words: [usize; 4],
-        _cap: Option<CapSlot>,
+        cap: Option<CapSlot>,
     ) -> ([usize; 4], Option<CapSlot>) {
         match StorageRequest::decode(words) {
+            Some(StorageRequest::SetLog) => (self.set_log(badge, cap).encode(), None),
             Some(request) => {
                 let (response, cap) = self.serve(badge, request);
                 (response.encode(), cap)

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

@@ -180,3 +180,18 @@ fn garbage_gets_a_malformed_reply() {
     let (words, cap) = s.handle_call(0, [99, 0, 0, 0], None);
     assert_eq!((words[0], cap), (MALFORMED, None));
 }
+
+#[test]
+fn only_the_unbadged_holder_sets_the_log_and_only_once() {
+    let mut s = server();
+    let log = CapSlot::new(7);
+    let set = |s: &mut Srv, badge| {
+        let (words, _) = s.handle_call(badge, StorageRequest::SetLog.encode(), log);
+        StorageResponse::decode(words).unwrap()
+    };
+    assert_eq!(set(&mut s, 5), StorageResponse::Error);
+    assert_eq!(s.log(), None);
+    assert_eq!(set(&mut s, 0), StorageResponse::Ok);
+    assert_eq!(s.log(), log);
+    assert_eq!(set(&mut s, 0), StorageResponse::Error);
+}