Fix for RSA Keys which are read only (#4744)

* Fix for RSA Keys which are read only

Sometimes an RSA Key file could be read only.
We currently failed because we also wanted to write.
Added an extra check if the file exists already and is not 0 in size.
If it does already exists and is larger then 0, then open in read only
mode.

Fixes #4644

* Updated code to work atomically

- Changed the code to work atomically
- Also show the alert generated from `Io`

* Fix spelling

src/main.rs

@@ -73,11 +73,9 @@ async fn main() -> Result<(), Error> {
     });
     init_logging(level).ok();
 
-    let extra_debug = matches!(level, LF::Trace | LF::Debug);
-
     check_data_folder().await;
-    auth::initialize_keys().unwrap_or_else(|_| {
-        error!("Error creating keys, exiting...");
+    auth::initialize_keys().unwrap_or_else(|e| {
+        error!("Error creating private key '{}'\n{e:?}\nExiting Vaultwarden!", CONFIG.private_rsa_key());
         exit(1);
     });
     check_web_vault();
@@ -91,6 +89,7 @@ async fn main() -> Result<(), Error> {
     schedule_jobs(pool.clone());
     crate::db::models::TwoFactor::migrate_u2f_to_webauthn(&mut pool.get().await.unwrap()).await.unwrap();
 
+    let extra_debug = matches!(level, LF::Trace | LF::Debug);
     launch_rocket(pool, extra_debug).await // Blocks until program termination.
 }
 
@@ -514,7 +513,7 @@ async fn launch_rocket(pool: db::DbPool, extra_debug: bool) -> Result<(), Error>
 
     tokio::spawn(async move {
         tokio::signal::ctrl_c().await.expect("Error setting Ctrl-C handler");
-        info!("Exiting vaultwarden!");
+        info!("Exiting Vaultwarden!");
         CONFIG.shutdown();
     });