run_command: wait for command to run indefinitely

src/qemu.rs

@@ -750,6 +750,16 @@ impl Qemu {
             let _ = updates.send(Output::Command(line));
         };
 
+        // Set read timeout to None so we can block indefinitely in case the VM
+        // is having a hard time, like being overloaded. See #40.
+        // But reset it back to the old value when we're done.
+        let old_timeout = qga.read_timeout()?;
+        scopeguard::defer! {
+            // Restore old timeout
+            let _ = qga.set_read_timeout(old_timeout);
+        }
+        qga.set_read_timeout(None)?;
+
         let output_stream = connect_to_uds(&self.command_sock)
             .context("Failed to connect to command output socket")?;
 

src/qga.rs

@@ -99,6 +99,21 @@ impl QgaWrapper {
         bail!("Timed out waiting for QGA connection");
     }
 
+    /// Set the read timeout of the inner UnixStream.
+    ///
+    /// If the provided value is [`None`], then [`read`] calls will block
+    /// indefinitely. An [`Err`] is returned if the zero [`Duration`] is passed to this
+    /// method.
+    pub fn set_read_timeout(&self, timeout: Option<Duration>) -> Result<()> {
+        self.stream.set_read_timeout(timeout)?;
+        Ok(())
+    }
+
+    /// Returns the read timeout of the inner UnixStream.
+    pub fn read_timeout(&self) -> Result<Option<Duration>> {
+        Ok(self.stream.read_timeout()?)
+    }
+
     /// Run a command inside the guest
     pub fn guest_exec(
         &self,