crosvm: remove stdin from pollables at EOF/error

If reading from stdin returns EOF or an error, remove it from the list
of pollables.

BUG=none
TEST=`vm_launcher start` and check that crosvm no longer pegs CPU

Change-Id: I7971058701e6145884de9c52a8dd5b829373637b
Reviewed-on: https://chromium-review.googlesource.com/745961
Commit-Ready: Stephen Barber <smbarber@chromium.org>
Tested-by: Stephen Barber <smbarber@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>

1 files changed, 16 insertions, 7 deletions

diff --git a/src/main.rs b/src/main.rs
index caaf3de..ac7350a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -713,13 +713,22 @@ fn run_control(mut vm: Vm,
                 }
                 STDIN => {
                     let mut out = [0u8; 64];
-                    let count = stdin_lock.read_raw(&mut out[..]).unwrap_or_default();
-                    if count != 0 {
-                        stdio_serial
-                            .lock()
-                            .unwrap()
-                            .queue_input_bytes(&out[..count])
-                            .expect("failed to queue bytes into serial port");
+                    match stdin_lock.read_raw(&mut out[..]) {
+                        Ok(0) => {
+                            // Zero-length read indicates EOF. Remove from pollables.
+                            pollables.retain(|&pollable| pollable.0 != STDIN);
+                        },
+                        Err(e) => {
+                            warn!("error while reading stdin: {:?}", e);
+                            pollables.retain(|&pollable| pollable.0 != STDIN);
+                        },
+                        Ok(count) => {
+                            stdio_serial
+                                .lock()
+                                .unwrap()
+                                .queue_input_bytes(&out[..count])
+                                .expect("failed to queue bytes into serial port");
+                        },
                     }
                 }
                 CHILD_SIGNAL => {