Apply daemonize for unix

Cargo.toml

@@ -52,6 +52,9 @@ nix = { version = "0.29", default-features = false, features = [
 android_logger = "0.14"
 jni = { version = "0.21", default-features = false }
 
+[target.'cfg(unix)'.dependencies]
+daemonize = "0.5"
+
 [target.'cfg(target_os = "windows")'.dependencies]
 windows-service = "0.7"
 

src/args.rs

@@ -100,8 +100,7 @@ pub struct Args {
     #[arg(short, long, value_name = "level", value_enum, default_value = "info")]
     pub verbosity: ArgVerbosity,
 
-    /// Daemonize the process as Windows service
-    #[cfg(target_os = "windows")]
+    /// Daemonize for unix family or run as Windows service
     #[arg(long)]
     pub daemonize: bool,
 }
@@ -144,7 +143,6 @@ impl Default for Args {
             udp_timeout: 10,
             verbosity: ArgVerbosity::Info,
             virtual_dns_pool: IpCidr::from_str("198.18.0.0/15").unwrap(),
-            #[cfg(target_os = "windows")]
             daemonize: false,
         }
     }

src/bin/main.rs

@@ -5,6 +5,19 @@ async fn main() -> Result<(), BoxError> {
     dotenvy::dotenv().ok();
     let args = Args::parse_args();
 
+    #[cfg(unix)]
+    if args.daemonize {
+        let stdout = std::fs::File::create("/tmp/tun2proxy.out")?;
+        let stderr = std::fs::File::create("/tmp/tun2proxy.err")?;
+        let daemonize = daemonize::Daemonize::new()
+            .working_directory("/tmp")
+            .umask(0o777)
+            .stdout(stdout)
+            .stderr(stderr)
+            .privileged_action(|| "Executed before drop privileges");
+        let _ = daemonize.start()?;
+    }
+
     #[cfg(target_os = "windows")]
     if args.daemonize {
         tun2proxy::win_svc::start_service()?;