Make logging race-free using a global lock & macro (#309)

* Make logging race-free using a global lock & macro

* Fix clippy complaint

* Fix import for MacOS

* Make `mt_log` expand to an expression

Author: cyqsimon

Cargo.lock

@@ -41,6 +41,7 @@ simplelog = "0.12.1"
 clap-verbosity-flag = "2.0.1"
 derivative = "2.2.0"
 itertools = "0.11.0"
+once_cell = "1.18.0"
 
 [target.'cfg(target_os="windows")'.dependencies]
 netstat2 = "0.9.1"

Cargo.toml

@@ -7,9 +7,10 @@ use std::{
     net::{IpAddr, Ipv4Addr, Ipv6Addr},
 };
 
-use log::warn;
-
-use crate::network::{Connection, LocalSocket, Utilization};
+use crate::{
+    mt_log,
+    network::{Connection, LocalSocket, Utilization},
+};
 
 static RECALL_LENGTH: usize = 5;
 static MAX_BANDWIDTH_ITEMS: usize = 1000;
@@ -141,12 +142,13 @@ impl UIState {
                     },
                 ) {
                     Some((lookalike, name)) => {
-                        warn!(
+                        mt_log!(
+                            warn,
                             r#""{name}" owns a similar looking connection, but its local ip doesn't match."#
                         );
-                        warn!("Looking for: {local_socket}; found: {lookalike}");
+                        mt_log!(warn, "Looking for: {local_socket}; found: {lookalike}");
                     }
-                    None => warn!("Cannot determine which process owns {local_socket}."),
+                    None => mt_log!(warn, "Cannot determine which process owns {local_socket}."),
                 };
             }
         }

src/display/ui_state.rs

@@ -28,6 +28,7 @@ use network::{
     dns::{self, IpTable},
     LocalSocket, Sniffer, Utilization,
 };
+use once_cell::sync::Lazy;
 use pnet::datalink::{DataLinkReceiver, NetworkInterface};
 use ratatui::backend::{Backend, CrosstermBackend};
 use simplelog::WriteLogger;
@@ -36,6 +37,21 @@ use crate::cli::Opt;
 
 const DISPLAY_DELTA: Duration = Duration::from_millis(1000);
 
+/// Lock guard to prevent races during logging.
+static LOG_LOCK: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
+
+/// Thread-safe log macro with a global Mutex guard.
+#[macro_export]
+macro_rules! mt_log {
+    ($log_macro: ident, $($fmt_args:expr),*) => {{
+        let guard = $crate::LOG_LOCK
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner());
+        log::$log_macro!($($fmt_args,)*);
+        drop(guard);
+    }};
+}
+
 fn main() -> anyhow::Result<()> {
     let opts = Opt::parse();
 

src/main.rs

@@ -1,9 +1,11 @@
 use std::{ffi::OsStr, net::IpAddr, process::Command, sync::OnceLock};
 
-use log::warn;
 use regex::Regex;
 
-use crate::network::{LocalSocket, Protocol};
+use crate::{
+    mt_log,
+    network::{LocalSocket, Protocol},
+};
 
 #[allow(dead_code)]
 #[derive(Debug, Clone)]
@@ -120,15 +122,24 @@ impl RawConnection {
         let process = &self.process_name;
 
         let Some(ip) = self.get_local_ip() else {
-            warn!(r#"Failed to get the local IP of a connection belonging to "{process}"."#);
+            mt_log!(
+                warn,
+                r#"Failed to get the local IP of a connection belonging to "{process}"."#
+            );
             return None;
         };
         let Some(port) = self.get_local_port() else {
-            warn!(r#"Failed to get the local port of a connection belonging to "{process}"."#);
+            mt_log!(
+                warn,
+                r#"Failed to get the local port of a connection belonging to "{process}"."#
+            );
             return None;
         };
         let Some(protocol) = self.get_protocol() else {
-            warn!(r#"Failed to get the protocol of a connection belonging to "{process}"."#);
+            mt_log!(
+                warn,
+                r#"Failed to get the protocol of a connection belonging to "{process}"."#
+            );
             return None;
         };