refactor daemon polling and event handling

src/daemon.rs

@@ -10,7 +10,7 @@ use std::{
 
 use iddqd::{BiHashMap, IdOrdMap};
 
-use mio::{Events, Interest, Poll, Token, net::UnixListener, unix::SourceFd};
+use mio::{Events, Interest, Poll, Token, event::Event, net::UnixListener, unix::SourceFd};
 
 use rustix::{buffer::spare_capacity, net::SocketFlags, process::Uid};
 
@@ -53,7 +53,8 @@ fn next_token() -> Token {
 
     // If the increment wrapped to 0, then we just increment it again.
     if tok == 0 {
-        return Token(NEXT_TOKEN_NUMBER.fetch_add(1, Ordering::SeqCst));
+        warn!("File descriptor token wrapped. That's... a lot.");
+        return next_token();
     }
 
     Token(tok)
@@ -274,6 +275,7 @@ impl Daemon {
         self.fd.as_fd()
     }
 }
+const DAEMON: Token = Token(0);
 
 /// Private helpers.
 impl Daemon {
@@ -368,7 +370,6 @@ impl Daemon {
             );
         }
         let mut daemon_source = SourceFd(&raw_fd);
-        const DAEMON: Token = Token(0);
         self.tokfd
             .insert_unique(TokenFd {
                 token: DAEMON,
@@ -385,15 +386,24 @@ impl Daemon {
 
         loop {
             if tracing::enabled!(tracing::Level::DEBUG) {
-                //
                 trace!("Daemon loop iteration, with file descriptors: ");
                 for info in &self.fd_info {
                     trace!("- {}", info.display());
                 }
             }
 
-            match self.poller.poll(&mut events, TIMEOUT_NEVER) {
-                Ok(_) => {
+            let poll_result = self.poller.poll(&mut events, TIMEOUT_NEVER);
+            self.handle_poll(poll_result, &events)?;
+        }
+    }
+
+    fn handle_poll(
+        &mut self,
+        poll_result: Result<(), IoError>,
+        events: &Events,
+    ) -> Result<(), IoError> {
+        match poll_result {
+            Ok(()) => {
                 trace!(
                     "mio::Poller::poll() got events: {:?}",
                     events.iter().size_hint().0,
@@ -408,11 +418,12 @@ impl Daemon {
             },
             Err(e) if e.kind() == IoErrorKind::Interrupted => {
                 // EINTR is silly.
-                    continue;
+                // Return early, and poll() again.
+                return Ok(());
             },
             Err(e) => {
                 if let Some(Errno::BADF) = e.raw_os_error().map(Errno::from_raw_os_error) {
-                        unreachable!("EBADF on poller fd; IO safety violation?");
+                    panic!("EBADF on poller fd; IO safety violation?");
                 }
                 warn!("mio Poll::poll() error: {e}");
                 self.fd_error_push(self.poller.as_raw_fd(), e)
@@ -422,8 +433,16 @@ impl Daemon {
             },
         }
 
-            for event in &events {
-                trace!("event is {event:?}");
+        for event in events {
+            self.handle_event(event)?;
+        }
+
+        Ok(())
+    }
+
+    fn handle_event(&mut self, event: &Event) -> Result<(), IoError> {
+        trace!("Handling event {event:?}");
+
         match event.token() {
             DAEMON => {
                 let is_sock = self.main_fd_info().kind == FdKind::Socket;
@@ -431,7 +450,8 @@ impl Daemon {
                     // SAFETY: oh boy: disjoint borrows with extra steps.
                     let file_fd = unsafe { BorrowedFd::borrow_raw(self.fd.as_raw_fd()) };
                     self.read_cmd(&file_fd).unwrap();
-                            continue;
+
+                    return Ok(());
                 }
 
                 // Accept, first.
@@ -453,7 +473,8 @@ impl Daemon {
                                     self.fd
                                 )
                             })?;
-                                continue;
+
+                        return Ok(());
                     },
                 };
 
@@ -467,7 +488,7 @@ impl Daemon {
             other_token => {
                 // This must be a stream fd.
                 let stream_fd = self.fd_for_token(other_token).unwrap_or_else(|| {
-                            unreachable!("tried to get fd for no-existent token? {other_token:?}")
+                    unreachable!("tried to get fd for non-existent token? {other_token:?}")
                 });
 
                 if event.is_read_closed() {
@@ -479,8 +500,8 @@ impl Daemon {
                 }
             },
         }
-            }
-        }
+
+        Ok(())
     }
 }