use thread pool to avoid zombie processes

wg-event-gen/src/listener.rs

@@ -4,6 +4,7 @@ use std::path::PathBuf;
 use std::process::Command;
 use std::thread;
 use std::time::SystemTime;
+use threadpool::ThreadPool;
 
 pub trait EventListener {
     fn name(&self) -> &'static str;
@@ -87,11 +88,13 @@ impl EventListener for LogListener {
 
 pub struct ScriptListener {
     pub script: PathBuf,
+    pub pool: ThreadPool,
 }
 
 impl ScriptListener {
     pub fn new(script: PathBuf) -> ScriptListener {
-        ScriptListener { script }
+        let pool = ThreadPool::new(4);
+        ScriptListener { script, pool }
     }
 
     fn peer_props<'a>(&self, peer: &'a Peer) -> String {
@@ -136,7 +139,7 @@ impl ScriptListener {
 
     fn call_sub<'a>(&self, args: Vec<&'a str>) {
         let mut cmd = self.mkcmd(args);
-        thread::spawn(move || {
+        self.pool.execute(move || {
             cmd.spawn().expect("Failed to call Script hooḱ!");
         });
     }