Minimize locking in schemes. Reenable pcid and ion launch in init. WIP: Userspace schemes

kernel/scheme/initfs.rs

@@ -1,4 +1,6 @@
 use collections::BTreeMap;
+use core::sync::atomic::{AtomicUsize, Ordering};
+use spin::RwLock;
 
 use syscall::{Error, Result};
 use super::Scheme;
@@ -9,9 +11,9 @@ struct Handle {
 }
 
 pub struct InitFsScheme {
-    next_id: usize,
+    next_id: AtomicUsize,
     files: BTreeMap<&'static [u8], &'static [u8]>,
-    handles: BTreeMap<usize, Handle>
+    handles: RwLock<BTreeMap<usize, Handle>>
 }
 
 impl InitFsScheme {
@@ -22,23 +24,22 @@ impl InitFsScheme {
         files.insert(b"bin/ion", include_bytes!("../../build/userspace/ion"));
         files.insert(b"bin/pcid", include_bytes!("../../build/userspace/pcid"));
         files.insert(b"bin/ps2d", include_bytes!("../../build/userspace/ps2d"));
-        files.insert(b"etc/init.rc", b"#initfs:bin/pcid\ninitfs:bin/ps2d\n#initfs:bin/ion");
+        files.insert(b"etc/init.rc", b"initfs:bin/pcid\ninitfs:bin/ps2d\ninitfs:bin/ion");
 
         InitFsScheme {
-            next_id: 0,
+            next_id: AtomicUsize::new(0),
             files: files,
-            handles: BTreeMap::new()
+            handles: RwLock::new(BTreeMap::new())
         }
     }
 }
 
 impl Scheme for InitFsScheme {
-    fn open(&mut self, path: &[u8], _flags: usize) -> Result<usize> {
+    fn open(&self, path: &[u8], _flags: usize) -> Result<usize> {
         let data = self.files.get(path).ok_or(Error::NoEntry)?;
 
-        let id = self.next_id;
-        self.next_id += 1;
-        self.handles.insert(id, Handle {
+        let id = self.next_id.fetch_add(1, Ordering::SeqCst);
+        self.handles.write().insert(id, Handle {
             data: data,
             seek: 0
         });
@@ -46,15 +47,15 @@ impl Scheme for InitFsScheme {
         Ok(id)
     }
 
-    fn dup(&mut self, file: usize) -> Result<usize> {
+    fn dup(&self, file: usize) -> Result<usize> {
         let (data, seek) = {
-            let handle = self.handles.get(&file).ok_or(Error::BadFile)?;
+            let handles = self.handles.read();
+            let handle = handles.get(&file).ok_or(Error::BadFile)?;
             (handle.data, handle.seek)
         };
 
-        let id = self.next_id;
-        self.next_id += 1;
-        self.handles.insert(id, Handle {
+        let id = self.next_id.fetch_add(1, Ordering::SeqCst);
+        self.handles.write().insert(id, Handle {
             data: data,
             seek: seek
         });
@@ -62,8 +63,9 @@ impl Scheme for InitFsScheme {
         Ok(id)
     }
 
-    fn read(&mut self, file: usize, buffer: &mut [u8]) -> Result<usize> {
-        let mut handle = self.handles.get_mut(&file).ok_or(Error::BadFile)?;
+    fn read(&self, file: usize, buffer: &mut [u8]) -> Result<usize> {
+        let mut handles = self.handles.write();
+        let mut handle = handles.get_mut(&file).ok_or(Error::BadFile)?;
 
         let mut i = 0;
         while i < buffer.len() && handle.seek < handle.data.len() {
@@ -75,15 +77,15 @@ impl Scheme for InitFsScheme {
         Ok(i)
     }
 
-    fn write(&mut self, _file: usize, _buffer: &[u8]) -> Result<usize> {
+    fn write(&self, _file: usize, _buffer: &[u8]) -> Result<usize> {
         Err(Error::NotPermitted)
     }
 
-    fn fsync(&mut self, _file: usize) -> Result<()> {
+    fn fsync(&self, _file: usize) -> Result<()> {
         Ok(())
     }
 
-    fn close(&mut self, file: usize) -> Result<()> {
-        self.handles.remove(&file).ok_or(Error::BadFile).and(Ok(()))
+    fn close(&self, file: usize) -> Result<()> {
+        self.handles.write().remove(&file).ok_or(Error::BadFile).and(Ok(()))
     }
 }