virtme-ng-init: set proper ownership of the default console device

Running a virtme-ng session as non-root may trigger some /dev/stdout
permission errors, for example running a kselftest as a regular user:

  $ vng --user $USER -- make kselftest TARGETS=size
  make[3]: Entering directory '/home/arighi/src/linux/tools/testing/selftests/size'
  make[3]: Leaving directory '/home/arighi/src/linux/tools/testing/selftests/size'
  make[3]: Entering directory '/home/arighi/src/linux/tools/testing/selftests/size'
  TAP version 13
  1..1
  /bin/sh: 100: cannot create /dev/stdout: Permission denied
  # selftests: size: get_size
  /bin/sh: 127: cannot create /dev/stdout: Permission denied
  not ok 1 selftests: size: get_size # exit=2
  make[3]: Leaving directory '/home/arighi/src/linux/tools/testing/selftests/size'

This happens because /dev/stdout points to the default console device
that has root:root ownership by default.

Fix this by setting the proper ownership of the console device.

This fixes issue #5.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

src/main.rs

@@ -685,7 +685,7 @@ fn clear_virtme_envs() {
     }
 }
 
-fn configure_terminal(consdev: &str) {
+fn configure_terminal(consdev: &str, uid: u32) {
     if let Ok(params) = env::var("virtme_stty_con") {
         let output = Command::new("stty")
             .args(params.split_whitespace())
@@ -695,6 +695,8 @@ fn configure_terminal(consdev: &str) {
             // Replace the current init process with a shell session.
             .output();
         log!("{}", String::from_utf8_lossy(&output.unwrap().stderr));
+        // Set proper user ownership on the default console device
+        utils::do_chown(&consdev, uid, uid).ok();
     }
 }
 
@@ -798,7 +800,7 @@ fn run_user_session() {
             return;
         }
     };
-    configure_terminal(consdev.as_str());
+    configure_terminal(consdev.as_str(), uid);
 
     init_xdg_runtime_dir(uid);