From 47e294fcddc4136feda480da802d0f08135295bf Mon Sep 17 00:00:00 2001
From: AlexandreBrg <burgoni.alexandre@protonmail.com>
Date: Tue, 4 Jan 2022 21:58:05 +0100
Subject: [PATCH] lumper: Add serial console file option

  * New cli option --console STRING
  * Lumper guest output now goes to a file if console file specified

Signed-off-by: AlexandreBrg <burgoni.alexandre@protonmail.com>
---
 src/main.rs                   |  7 ++++++-
 src/vmm/src/devices/serial.rs |  8 ++++----
 src/vmm/src/lib.rs            | 26 +++++++++++++++++++++++---
 3 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 135afec..a82fa8c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,6 +21,10 @@ struct VMMOpts {
     /// A level of verbosity, and can be used multiple times
     #[clap(short, long, parse(from_occurrences))]
     verbose: i32,
+
+    /// Stdout console file path
+    #[clap(long)]
+    console: Option<String>
 }
 
 #[derive(Debug)]
@@ -42,7 +46,8 @@ fn main() -> Result<(), Error> {
     // * Number of virtual CPUs
     // * Memory size (in MB)
     // * Path to a Linux kernel
-    vmm.configure(opts.cpus, opts.memory, &opts.kernel)
+    // * Optional path to console file
+    vmm.configure(opts.cpus, opts.memory, &opts.kernel, opts.console)
         .map_err(Error::VmmConfigure)?;
 
     // Run the VMM
diff --git a/src/vmm/src/devices/serial.rs b/src/vmm/src/devices/serial.rs
index e21ca9c..e1a2725 100644
--- a/src/vmm/src/devices/serial.rs
+++ b/src/vmm/src/devices/serial.rs
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0
 
-use std::io::{stdout, Error, Result, Stdout};
+use std::io::{Error, Result, Write};
 use std::ops::Deref;
 
 use vm_superio::serial::NoEvents;
@@ -41,16 +41,16 @@ pub(crate) struct LumperSerial {
     eventfd: EventFdTrigger,
 
     // serial is the actual serial device.
-    pub serial: Serial<EventFdTrigger, NoEvents, Stdout>,
+    pub serial: Serial<EventFdTrigger, NoEvents, Box<dyn Write + Send>>,
 }
 
 impl LumperSerial {
-    pub fn new() -> Result<Self> {
+    pub fn new(output: Box<dyn Write + Send>) -> Result<Self> {
         let eventfd = EventFdTrigger::new(libc::EFD_NONBLOCK).unwrap();
 
         Ok(LumperSerial {
             eventfd: eventfd.try_clone()?,
-            serial: Serial::new(eventfd.try_clone()?, stdout()),
+            serial: Serial::new(eventfd.try_clone()?, Box::new(output)),
         })
     }
 
diff --git a/src/vmm/src/lib.rs b/src/vmm/src/lib.rs
index 55d8511..160dd2f 100644
--- a/src/vmm/src/lib.rs
+++ b/src/vmm/src/lib.rs
@@ -8,22 +8,24 @@ extern crate linux_loader;
 extern crate vm_memory;
 extern crate vm_superio;
 
+use std::io::stdout;
 use std::os::unix::io::AsRawFd;
 use std::os::unix::prelude::RawFd;
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::{io, path::PathBuf};
+use std::fs::File;
 
 use kvm_bindings::{kvm_userspace_memory_region, KVM_MAX_CPUID_ENTRIES};
 use kvm_ioctls::{Kvm, VmFd};
 use linux_loader::loader::{self, KernelLoaderResult};
 use vm_memory::{Address, GuestAddress, GuestMemory, GuestMemoryMmap, GuestMemoryRegion};
 use vmm_sys_util::terminal::Terminal;
-
 mod cpu;
 use cpu::{cpuid, mptable, Vcpu};
 mod devices;
 use devices::serial::LumperSerial;
+
 mod epoll_context;
 use epoll_context::{EpollContext, EPOLL_EVENTS_LEN};
 mod kernel;
@@ -62,6 +64,8 @@ pub enum Error {
     StdinWrite(vm_superio::serial::Error<io::Error>),
     /// Terminal configuration error
     TerminalConfigure(kvm_ioctls::Error),
+    /// Console configuration error
+    ConsoleError(io::Error),
 }
 
 /// Dedicated [`Result`](https://doc.rust-lang.org/std/result/) type.
@@ -96,7 +100,7 @@ impl VMM {
             guest_memory: GuestMemoryMmap::default(),
             vcpus: vec![],
             serial: Arc::new(Mutex::new(
-                LumperSerial::new().map_err(Error::SerialCreation)?,
+                LumperSerial::new(Box::new(stdout())).map_err(Error::SerialCreation)?,
             )),
             epoll,
         };
@@ -160,6 +164,21 @@ impl VMM {
         Ok(())
     }
 
+    pub fn configure_console(
+        &mut self,
+        console_path: Option<String>
+    ) -> Result<()> {
+        if let Some(console_path) = console_path {
+            // We create the file if it does not exist, else we open
+            let file = File::create(&console_path).map_err(Error::ConsoleError)?;
+
+            let mut serial = self.serial.lock().unwrap();
+            *serial = LumperSerial::new(Box::new(file)).map_err(Error::SerialCreation)?;
+        }
+
+        Ok(())
+    }
+
     pub fn configure_vcpus(
         &mut self,
         num_vcpus: u8,
@@ -247,7 +266,8 @@ impl VMM {
         }
     }
 
-    pub fn configure(&mut self, num_vcpus: u8, mem_size_mb: u32, kernel_path: &str) -> Result<()> {
+    pub fn configure(&mut self, num_vcpus: u8, mem_size_mb: u32, kernel_path: &str, console: Option<String>) -> Result<()> {
+        self.configure_console(console)?;
         self.configure_memory(mem_size_mb)?;
         let kernel_load = kernel::kernel_setup(&self.guest_memory, PathBuf::from(kernel_path))?;
         self.configure_io()?;