fix(virtio/console): create pty for console interaction in backend

Signed-off-by: Jose Martins <[email protected]>

src/api/src/types.rs

@@ -84,7 +84,7 @@ pub struct BaoDMInfo {
     pub fd: i32,
 }
 
-#[derive(Debug, Deserialize, Serialize, PartialEq)]
+#[derive(Debug, Clone, Deserialize, Serialize, PartialEq)]
 /// Struct representing a Device configuration.
 ///
 /// # Attributes
@@ -123,6 +123,8 @@ pub struct DeviceConfig {
     pub guest_cid: Option<u64>,
     // Vhost-user device specific fields
     pub socket_path: Option<String>,
+    // Console device specific fields
+    pub pty_alias: Option<String>,
 }
 
 #[derive(Debug, Deserialize, Serialize, PartialEq)]

src/virtio/src/console/virtio/console_handler.rs

@@ -2,6 +2,7 @@ use super::queue_handler::{INPUT_QUEUE_INDEX, OUTPUT_QUEUE_INDEX};
 use crate::device::SignalUsedQueue;
 use std::io::Write;
 use std::result;
+use std::sync::{Arc, Mutex};
 use virtio_console::console::{Console, Error as ConsoleError};
 use virtio_queue::{Queue, QueueOwnedT, QueueT};
 use vm_memory::bitmap::AtomicBitmap;
@@ -14,7 +15,7 @@ pub struct ConsoleQueueHandler<S: SignalUsedQueue, W: Write + WriteVolatile> {
     pub mem: GuestMemoryMmap,
     pub input_queue: Queue,
     pub output_queue: Queue,
-    pub console: Console<W>,
+    pub console: Arc<Mutex<Console<W>>>,
 }
 
 impl<S, W> ConsoleQueueHandler<S, W>
@@ -32,17 +33,21 @@ where
         // To see why this is done in a loop, please look at the `Queue::enable_notification`
         // comments in `virtio_queue`.
         loop {
-            if self.console.is_input_buffer_empty() {
+            if self.console.lock().unwrap().is_input_buffer_empty() {
                 break;
             }
 
             // Disable the notifications.
             self.input_queue.disable_notification(&self.mem)?;
 
-            while !self.console.is_input_buffer_empty() {
+            while !self.console.lock().unwrap().is_input_buffer_empty() {
                 // Process the queue.
                 if let Some(mut chain) = self.input_queue.iter(&self.mem.clone())?.next() {
-                    let sent_bytes = self.console.process_receiveq_chain(&mut chain)?;
+                    let sent_bytes = self
+                        .console
+                        .lock()
+                        .unwrap()
+                        .process_receiveq_chain(&mut chain)?;
 
                     if sent_bytes > 0 {
                         self.input_queue.add_used(
@@ -85,7 +90,10 @@ where
 
             // Process the queue.
             while let Some(mut chain) = self.output_queue.iter(&self.mem.clone())?.next() {
-                self.console.process_transmitq_chain(&mut chain)?;
+                self.console
+                    .lock()
+                    .unwrap()
+                    .process_transmitq_chain(&mut chain)?;
 
                 self.output_queue
                     .add_used(chain.memory(), chain.head_index(), 0)?;

src/virtio/src/console/virtio/device.rs

@@ -1,4 +1,5 @@
 use super::console_handler::ConsoleQueueHandler;
+use super::pty_handler::PtyHandler;
 use super::queue_handler::QueueHandler;
 use crate::device::{SingleFdSignalQueue, Subscriber, VirtioDeviceT};
 use crate::device::{VirtioDevType, VirtioDeviceCommon};
@@ -9,6 +10,7 @@ use event_manager::{
     EventManager, MutEventSubscriber, RemoteEndpoint, Result as EvmgrResult, SubscriberId,
 };
 use std::borrow::{Borrow, BorrowMut};
+use std::os::unix::net::UnixStream;
 use std::sync::{Arc, Mutex};
 use virtio_bindings::virtio_config::VIRTIO_F_IN_ORDER;
 use virtio_console::console::Console;
@@ -27,6 +29,7 @@ use vm_device::MutDeviceMmio;
 pub struct VirtioConsole {
     pub common: VirtioDeviceCommon,
     pub endpoint: RemoteEndpoint<Subscriber>,
+    pub config: DeviceConfig,
 }
 
 impl VirtioDeviceT for VirtioConsole {
@@ -58,6 +61,7 @@ impl VirtioDeviceT for VirtioConsole {
         let console = Arc::new(Mutex::new(VirtioConsole {
             common: common_device,
             endpoint: remote_endpoint,
+            config: config.clone(),
         }));
 
         // Register the MMIO device within the device manager with the specified range.
@@ -114,8 +118,12 @@ impl VirtioDeviceActions for VirtioConsole {
     type E = Error;
 
     fn activate(&mut self) -> Result<()> {
+        // Create socket to act as console output and forward it to pty
+        let (socket_out, socket_in) = UnixStream::pair().unwrap();
+        socket_in.set_nonblocking(true).unwrap();
+
         // Create the backend.
-        let console = Console::default();
+        let console = Arc::new(Mutex::new(Console::new(socket_out)));
 
         // Create the driver notify object.
         let driver_notify = SingleFdSignalQueue {
@@ -132,14 +140,16 @@ impl VirtioDeviceActions for VirtioConsole {
             mem: self.common.mem(),
             input_queue: self.common.config.queues.remove(0),
             output_queue: self.common.config.queues.remove(0),
-            console,
+            console: Arc::clone(&console),
         };
 
         // Create the queue handler.
+        let input_ioeventfd = ioevents.remove(0);
+        let output_ioeventfd = ioevents.remove(0);
         let handler = Arc::new(Mutex::new(QueueHandler {
             inner,
-            input_ioeventfd: ioevents.remove(0),
-            output_ioeventfd: ioevents.remove(0),
+            input_ioeventfd: input_ioeventfd.try_clone().unwrap(),
+            output_ioeventfd,
         }));
 
         // Register the queue handler with the `EventManager`. We could record the `sub_id`
@@ -152,6 +162,20 @@ impl VirtioDeviceActions for VirtioConsole {
             })
             .unwrap();
 
+        // Create pty handler and register it as a event subscriber
+        let pty_handler = Arc::new(Mutex::new(PtyHandler::new(
+            socket_in,
+            Arc::clone(&console),
+            input_ioeventfd,
+            &self.config,
+        )));
+
+        self.endpoint
+            .call_blocking(|mgr| -> EvmgrResult<SubscriberId> {
+                Ok(mgr.add_subscriber(pty_handler))
+            })
+            .unwrap();
+
         // Set the device as activated.
         self.common.config.device_activated = true;
 

src/virtio/src/console/virtio/mod.rs

@@ -1,3 +1,4 @@
 pub mod console_handler;
 pub mod device;
+mod pty_handler;
 pub mod queue_handler;

src/virtio/src/console/virtio/pty_handler.rs

@@ -0,0 +1,117 @@
+use std::fs::{File, OpenOptions};
+use std::io::{Read, Write};
+use std::os::fd::AsRawFd;
+use std::os::unix::fs::OpenOptionsExt;
+use std::sync::{Arc, Mutex};
+
+use api::types::DeviceConfig;
+use event_manager::{EventOps, Events, MutEventSubscriber};
+use libc::IN_NONBLOCK;
+use std::os::unix::net::UnixStream;
+use virtio_console::console::Console;
+use vm_memory::WriteVolatile;
+use vmm_sys_util::epoll::EventSet;
+use vmm_sys_util::eventfd::EventFd;
+
+const SOURCE_PTY: u32 = 0;
+const SOURCE_SOCKET: u32 = 1;
+
+const BUFFER_SIZE: usize = 128;
+
+pub(super) struct PtyHandler<W: Write + WriteVolatile> {
+    pub pty: File,
+    pub socket: UnixStream,
+    pub console: Arc<Mutex<Console<W>>>,
+    pub input_ioeventfd: EventFd,
+}
+
+impl<W> PtyHandler<W>
+where
+    W: Write + WriteVolatile,
+{
+    pub fn new(
+        socket: UnixStream,
+        console: Arc<Mutex<Console<W>>>,
+        input_ioeventfd: EventFd,
+        config: &DeviceConfig,
+    ) -> Self {
+        let pty = OpenOptions::new()
+            .read(true)
+            .write(true)
+            .create(true)
+            .custom_flags(IN_NONBLOCK)
+            .open("/dev/ptmx")
+            .unwrap();
+
+        let pty_name = unsafe {
+            libc::grantpt(pty.as_raw_fd());
+            libc::unlockpt(pty.as_raw_fd());
+            std::ffi::CStr::from_ptr(libc::ptsname(pty.as_raw_fd()))
+        };
+
+        let pty_path = if let Some(pty_alias) = config.pty_alias.clone() {
+            std::os::unix::fs::symlink(pty_name.to_str().unwrap(), pty_alias.as_str())
+                .expect(&format!("Failed to create pty handler alias {}", pty_alias));
+            pty_alias
+        } else {
+            String::from(pty_name.to_str().unwrap())
+        };
+
+        println!("virtio-console device id {} at {}", config.id, pty_path);
+
+        Self {
+            pty,
+            socket,
+            console,
+            input_ioeventfd,
+        }
+    }
+}
+
+impl<W> MutEventSubscriber for PtyHandler<W>
+where
+    W: Write + WriteVolatile,
+{
+    fn init(&mut self, ops: &mut EventOps) {
+        ops.add(Events::with_data(
+            &self.pty,
+            SOURCE_PTY,
+            EventSet::IN | EventSet::EDGE_TRIGGERED,
+        ))
+        .expect("Failed to init pty event");
+
+        ops.add(Events::with_data(
+            &self.socket,
+            SOURCE_SOCKET,
+            EventSet::IN | EventSet::EDGE_TRIGGERED,
+        ))
+        .expect("Failed to init socket event");
+    }
+
+    fn process(&mut self, events: Events, ops: &mut EventOps) {
+        let mut buf = [0u8; BUFFER_SIZE];
+
+        match events.data() {
+            SOURCE_PTY => {
+                while let Ok(n) = self.pty.read(&mut buf) {
+                    let mut v: Vec<_> = buf[..n].iter().cloned().collect();
+                    self.console.lock().unwrap().enqueue_data(&mut v).unwrap();
+                    self.input_ioeventfd.write(1).unwrap();
+                }
+            }
+            SOURCE_SOCKET => {
+                while let Ok(n) = self.socket.read(&mut buf) {
+                    let v: Vec<_> = buf[..n].iter().cloned().collect();
+                    self.pty.write(&v).unwrap();
+                }
+            }
+            _ => {
+                log::error!(
+                    "PtyHandler unexpected event data: {}. Removing event...",
+                    events.data()
+                );
+                ops.remove(events).expect("Failed to remove event");
+            }
+        }
+    }
+}