diff --git a/src/scheme.rs b/src/scheme.rs
index 310bb88..a84865f 100644
--- a/src/scheme.rs
+++ b/src/scheme.rs
@@ -98,3 +98,99 @@ pub trait Scheme {
         Err(Error::new(EBADF))
     }
 }
+
+pub trait SchemeMut {
+    fn handle(&mut self, packet: &mut Packet) {
+        packet.a = Error::mux(match packet.a {
+            SYS_OPEN => self.open(unsafe { slice::from_raw_parts(packet.b as *const u8, packet.c) }, packet.d, packet.uid, packet.gid),
+            SYS_MKDIR => self.mkdir(unsafe { slice::from_raw_parts(packet.b as *const u8, packet.c) }, packet.d as u16, packet.uid, packet.gid),
+            SYS_RMDIR => self.rmdir(unsafe { slice::from_raw_parts(packet.b as *const u8, packet.c) }, packet.uid, packet.gid),
+            SYS_UNLINK => self.unlink(unsafe { slice::from_raw_parts(packet.b as *const u8, packet.c) }, packet.uid, packet.gid),
+
+            SYS_DUP => self.dup(packet.b),
+            SYS_READ => self.read(packet.b, unsafe { slice::from_raw_parts_mut(packet.c as *mut u8, packet.d) }),
+            SYS_WRITE => self.write(packet.b, unsafe { slice::from_raw_parts(packet.c as *const u8, packet.d) }),
+            SYS_LSEEK => self.seek(packet.b, packet.c, packet.d),
+            SYS_FEVENT => self.fevent(packet.b, packet.c),
+            SYS_FPATH => self.fpath(packet.b, unsafe { slice::from_raw_parts_mut(packet.c as *mut u8, packet.d) }),
+            SYS_FSTAT => self.fstat(packet.b, unsafe { &mut *(packet.c as *mut Stat) }),
+            SYS_FSYNC => self.fsync(packet.b),
+            SYS_FTRUNCATE => self.ftruncate(packet.b, packet.c),
+            SYS_CLOSE => self.close(packet.b),
+
+            _ => Err(Error::new(ENOSYS))
+        });
+    }
+
+    /* Scheme operations */
+    #[allow(unused_variables)]
+    fn open(&mut self, path: &[u8], flags: usize, uid: u32, gid: u32) -> Result<usize> {
+        Err(Error::new(ENOENT))
+    }
+
+    #[allow(unused_variables)]
+    fn mkdir(&mut self, path: &[u8], mode: u16, uid: u32, gid: u32) -> Result<usize> {
+        Err(Error::new(ENOENT))
+    }
+
+    #[allow(unused_variables)]
+    fn rmdir(&mut self, path: &[u8], uid: u32, gid: u32) -> Result<usize> {
+        Err(Error::new(ENOENT))
+    }
+
+    #[allow(unused_variables)]
+    fn unlink(&mut self, path: &[u8], uid: u32, gid: u32) -> Result<usize> {
+        Err(Error::new(ENOENT))
+    }
+
+    /* Resource operations */
+    #[allow(unused_variables)]
+    fn dup(&mut self, old_id: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn read(&mut self, id: usize, buf: &mut [u8]) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn write(&mut self, id: usize, buf: &[u8]) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn seek(&mut self, id: usize, pos: usize, whence: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn fevent(&mut self, id: usize, flags: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn fpath(&mut self, id: usize, buf: &mut [u8]) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn fstat(&mut self, id: usize, stat: &mut Stat) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn fsync(&mut self, id: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn ftruncate(&mut self, id: usize, len: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+
+    #[allow(unused_variables)]
+    fn close(&mut self, id: usize) -> Result<usize> {
+        Err(Error::new(EBADF))
+    }
+}