graphics/fbbootlogd: Get rid of fevent and tracking handles

Fbbootlogd doesn't do non-blocking operations, so fevent isn't needed.
And the kernel shouldn't pass closed handles to us and even if it does
due to a bug, it is harmless to silently ignore the fact that the handle
was closed.

graphics/fbbootlogd/src/scheme.rs

@@ -1,20 +1,13 @@
-use std::collections::{BTreeMap, VecDeque};
+use std::collections::VecDeque;
 
 use redox_scheme::Scheme;
-use syscall::{Error, EventFlags, Result, EBADF, EINVAL, ENOENT};
+use syscall::{Error, Result, EINVAL, ENOENT};
 
 use crate::display::Display;
 
-pub struct Handle {
-    pub events: EventFlags,
-    pub notified_read: bool,
-}
-
 pub struct FbbootlogScheme {
     display: Display,
     text_screen: console_draw::TextScreen,
-    next_id: usize,
-    pub handles: BTreeMap<usize, Handle>,
 }
 
 impl FbbootlogScheme {
@@ -22,8 +15,6 @@ impl FbbootlogScheme {
         FbbootlogScheme {
             display: Display::open_first_vt().expect("Failed to open display for vt"),
             text_screen: console_draw::TextScreen::new(),
-            next_id: 0,
-            handles: BTreeMap::new(),
         }
     }
 }
@@ -34,32 +25,10 @@ impl Scheme for FbbootlogScheme {
             return Err(Error::new(ENOENT));
         }
 
-        let id = self.next_id;
-        self.next_id += 1;
-
-        self.handles.insert(
-            id,
-            Handle {
-                events: EventFlags::empty(),
-                notified_read: false,
-            },
-        );
-
-        Ok(id)
+        Ok(0)
     }
 
-    fn fevent(&mut self, id: usize, flags: syscall::EventFlags) -> Result<syscall::EventFlags> {
-        let handle = self.handles.get_mut(&id).ok_or(Error::new(EBADF))?;
-
-        handle.notified_read = false;
-
-        handle.events = flags;
-        Ok(syscall::EventFlags::empty())
-    }
-
-    fn fpath(&mut self, id: usize, buf: &mut [u8]) -> Result<usize> {
-        let _handle = self.handles.get(&id).ok_or(Error::new(EBADF))?;
-
+    fn fpath(&mut self, _id: usize, buf: &mut [u8]) -> Result<usize> {
         let path = b"fbbootlog:";
 
         let mut i = 0;
@@ -71,27 +40,21 @@ impl Scheme for FbbootlogScheme {
         Ok(i)
     }
 
-    fn fsync(&mut self, id: usize) -> Result<usize> {
-        let _handle = self.handles.get(&id).ok_or(Error::new(EBADF))?;
-
-        return Ok(0);
+    fn fsync(&mut self, _id: usize) -> Result<usize> {
+        Ok(0)
     }
 
     fn read(
         &mut self,
-        id: usize,
+        _id: usize,
         _buf: &mut [u8],
         _offset: u64,
         _fcntl_flags: u32,
     ) -> Result<usize> {
-        let _handle = self.handles.get(&id).ok_or(Error::new(EBADF))?;
-
         Err(Error::new(EINVAL))
     }
 
-    fn write(&mut self, id: usize, buf: &[u8], _offset: u64, _fcntl_flags: u32) -> Result<usize> {
-        let _handle = self.handles.get(&id).ok_or(Error::new(EBADF))?;
-
+    fn write(&mut self, _id: usize, buf: &[u8], _offset: u64, _fcntl_flags: u32) -> Result<usize> {
         let mut map = self.display.map.lock().unwrap();
         let damage = self.text_screen.write(
             &mut console_draw::DisplayMap {
@@ -109,8 +72,7 @@ impl Scheme for FbbootlogScheme {
         Ok(buf.len())
     }
 
-    fn close(&mut self, id: usize) -> Result<usize> {
-        self.handles.remove(&id).ok_or(Error::new(EBADF))?;
+    fn close(&mut self, _id: usize) -> Result<usize> {
         Ok(0)
     }
 }