refactor: stop passing around std::io::Stdin objects

std::io::Stdin is a singleton, a programm cannot have more than one
stdin. Just replace the usage with a call to std::io::stdin()

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

src/vmm/src/builder.rs

@@ -163,7 +163,7 @@ fn create_vmm_and_vcpus(
         set_stdout_nonblocking();
 
         // Serial device setup.
-        let serial_device = setup_serial_device(event_manager, std::io::stdin(), io::stdout())?;
+        let serial_device = setup_serial_device(event_manager, io::stdout())?;
 
         // x86_64 uses the i8042 reset event as the Vmm exit event.
         let reset_evt = vcpus_exit_evt.try_clone().map_err(VmmError::EventFd)?;
@@ -554,7 +554,6 @@ pub fn build_microvm_from_snapshot(
 /// Sets up the serial device.
 pub fn setup_serial_device(
     event_manager: &mut EventManager,
-    input: std::io::Stdin,
     out: std::io::Stdout,
 ) -> Result<Arc<Mutex<BusDevice>>, VmmError> {
     let interrupt_evt = EventFdTrigger::new(EventFd::new(EFD_NONBLOCK).map_err(VmmError::EventFd)?);
@@ -568,7 +567,7 @@ pub fn setup_serial_device(
             },
             SerialOut::Stdout(out),
         ),
-        input: Some(input),
+        input: Some(std::io::stdin()),
     })));
     event_manager.add_subscriber(serial.clone());
     Ok(serial)
@@ -629,7 +628,7 @@ fn attach_legacy_devices_aarch64(
     if cmdline_contains_console {
         // Make stdout non-blocking.
         set_stdout_nonblocking();
-        let serial = setup_serial_device(event_manager, std::io::stdin(), std::io::stdout())?;
+        let serial = setup_serial_device(event_manager, std::io::stdout())?;
         vmm.mmio_device_manager
             .register_mmio_serial(vmm.vm.fd(), &mut vmm.resource_allocator, serial, None)
             .map_err(VmmError::RegisterMMIODevice)?;

src/vmm/src/device_manager/persist.rs

@@ -405,7 +405,6 @@ impl<'a> Persist<'a> for MMIODeviceManager {
                 if state.type_ == DeviceType::Serial {
                     let serial = crate::builder::setup_serial_device(
                         constructor_args.event_manager,
-                        std::io::stdin(),
                         std::io::stdout(),
                     )?;