check if mumd instance is running before starting

1 files changed, 17 insertions, 1 deletions

diff --git a/mumd/src/main.rs b/mumd/src/main.rs
index b83299f..c0caa77 100644
--- a/mumd/src/main.rs
+++ b/mumd/src/main.rs
@@ -8,7 +8,7 @@ use crate::network::ConnectionInfo;
 use crate::state::State;
 
 use futures::join;
-use ipc_channel::ipc::{IpcOneShotServer, IpcSender};
+use ipc_channel::ipc::{self, IpcOneShotServer, IpcSender};
 use log::*;
 use mumble_protocol::control::ControlPacket;
 use mumble_protocol::crypt::ClientCryptState;
@@ -25,6 +25,22 @@ async fn main() {
     setup_logger(std::io::stderr(), true);
     notify::init();
 
+    // check if another instance is live
+    let (tx_client, rx_client) =
+        ipc::channel::<mumlib::error::Result<Option<CommandResponse>>>().unwrap();
+    if let Ok(server_name) = fs::read_to_string(mumlib::SOCKET_PATH) {
+        if let Ok(tx0) = IpcSender::connect(server_name) {
+            if tx0.send((Command::Ping, tx_client)).is_ok() {
+                if matches!(rx_client.recv().unwrap(), Ok(Some(CommandResponse::Pong))) {
+                    error!("Another instance of mumd is already running");
+                    return;
+                } else {
+                    warn!("Ping with no response. Continuing...");
+                }
+            }
+        }
+    }
+
     // Oneshot channel for setting UDP CryptState from control task
     // For simplicity we don't deal with re-syncing, real applications would have to.
     let (crypt_state_sender, crypt_state_receiver) = mpsc::channel::<ClientCryptState>(1); // crypt state should always be consumed before sending a new one