Fix usbredir cleanups on stop

We need to kick all the helper threads to avoid "leaking" them.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

qemu-display/src/usbredir.rs

@@ -25,6 +25,7 @@ struct InnerHandler {
     stream_thread: JoinHandle<()>,
     ctxt: rusb::Context,
     ctxt_thread: Option<JoinHandle<()>>,
+    event: (UnixStream, UnixStream),
     quit: bool,
 }
 
@@ -36,7 +37,7 @@ struct Handler {
 impl DeviceHandler for Handler {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
         let mut inner = self.inner.lock().unwrap();
-        let read = match fd_poll_readable(inner.stream.as_raw_fd(), false) {
+        let read = match fd_poll_readable(inner.stream.as_raw_fd(), None) {
             Ok(true) => {
                 let read = inner.stream.read(buf);
                 if let Ok(0) = read {
@@ -99,17 +100,17 @@ impl Handler {
         };
 
         let (stream, peer) = UnixStream::pair()?;
-        chardev.proxy.register(dbg!(peer.as_raw_fd()).into()).await?;
+        chardev.proxy.register(peer.as_raw_fd().into()).await?;
 
         let c = ctxt.clone();
         let stream_fd = stream.as_raw_fd();
-        dbg!(stream_fd);
         // really annoying libusb/usbredir APIs...
+        let event = UnixStream::pair()?;
+        let event_fd = event.1.as_raw_fd();
         let stream_thread = std::thread::spawn(move || loop {
-            let ret = fd_poll_readable(stream_fd, true);
+            let ret = fd_poll_readable(stream_fd, Some(event_fd));
             c.interrupt_handle_events();
             if ret.is_err() {
-                dbg!();
                 break;
             }
         });
@@ -119,6 +120,7 @@ impl Handler {
                 device_fd,
                 stream,
                 stream_thread,
+                event,
                 quit: false,
                 ctxt: ctxt.clone(),
                 ctxt_thread: Default::default(),
@@ -130,10 +132,9 @@ impl Handler {
         let inner = handler.inner.clone();
         let ctxt_thread = std::thread::spawn(move || loop {
             if inner.lock().unwrap().quit {
-                dbg!();
                 break;
             }
-            if let Ok(true) = fd_poll_readable(stream_fd, false) {
+            if let Ok(true) = fd_poll_readable(stream_fd, None) {
                 redirdev.read_peer().unwrap();
             }
             if redirdev.has_data_to_write() > 0 {
@@ -152,18 +153,13 @@ impl Handler {
     }
 }
 
-impl Drop for InnerHandler {
-    fn drop(&mut self) {
-        //FIXME: for some reason close stream doesn't HUP qemu ??
-        dbg!()
-    }
-}
-
 impl Drop for Handler {
     fn drop(&mut self) {
         let mut inner = self.inner.lock().unwrap();
         inner.quit = true;
         inner.ctxt.interrupt_handle_events();
+        // stream will be dropped and stream_thread will kick context_thread
+        inner.event.0.write(&[0]).unwrap();
     }
 }
 
@@ -239,22 +235,30 @@ impl UsbRedir {
     }
 }
 
-fn fd_poll_readable(fd: RawFd, wait: bool) -> std::io::Result<bool> {
-    let mut fds = [libc::pollfd {
+fn fd_poll_readable(fd: RawFd, wait: Option<RawFd>) -> std::io::Result<bool> {
+    let mut fds = vec![libc::pollfd {
         fd,
         events: libc::POLLIN|libc::POLLHUP,
         revents: 0,
     }];
-    let ret = unsafe { libc::poll(fds.as_mut_ptr(), 1, if wait { -1 } else { 0 }) };
-    if ret > 0 {
-        if fds[0].revents & libc::POLLHUP != 0 {
-            Err(std::io::Error::new(std::io::ErrorKind::BrokenPipe, "hup"))
-        } else {
-            Ok(fds[0].revents & libc::POLLIN != 0)
-        }
+    if let Some(wait) = wait {
+        fds.push(libc::pollfd {
+            fd: wait,
+            events: libc::POLLIN|libc::POLLHUP,
+            revents: 0,
+        });
+    }
+    let ret = unsafe { libc::poll(fds.as_mut_ptr(),
+                                  fds.len() as _,
+                                  if wait.is_some() { -1 } else { 0 }) };
+    if ret < 0 {
+        Err(std::io::Error::last_os_error())
     } else if ret == 0 {
         Ok(false)
+    } else if fds[0].revents & libc::POLLHUP != 0 ||
+        (wait.is_some() && fds[1].revents & libc::POLLIN != 0) {
+        Err(std::io::Error::new(std::io::ErrorKind::BrokenPipe, "hup"))
     } else {
-        Err(std::io::Error::last_os_error())
+        Ok(fds[0].revents & libc::POLLIN != 0)
     }
 }