Don't try to call empty event handler path.

src/eventhook.cpp

@@ -22,30 +22,38 @@
 #include "eventhook.h"
 
 
-p3::eventHook::eventHook(config& c, phonebook& p) : 
+p3::eventHook::eventHook(config& c, phonebook& p) :
 	conf(c),
 	book(p),
 	command(conf.get_string("hook:command"))
 {
+	if (command == "none") {
+		command = "";
+	}
 	signal(SIGCHLD, SIG_IGN);
 }
 
-std::list<p3::eventHook::callback_type>::iterator p3::eventHook::register_callback(callback_type c) {
+std::list<p3::eventHook::callback_type>::iterator p3::eventHook::register_callback(const callback_type& c) {
 	return callbacks.insert(callbacks.end(), c);
 }
 
-void p3::eventHook::unregister_callback(std::list<p3::eventHook::callback_type>::iterator id) {
+void p3::eventHook::unregister_callback(const std::list<p3::eventHook::callback_type>::iterator& id) {
 	callbacks.erase(id);
 }
 
-void p3::eventHook::run_call_hook(std::string event, int cid, std::string nr, std::string data) {
+void p3::eventHook::run_call_hook(const std::string& event, int cid, const std::string& nr, const std::string& data) {
 	run_hook(event, std::to_string(cid), book.address_by_nr(nr), data);
 }
 
-void p3::eventHook::run_hook(std::string event, const std::string& a2, const std::string& a3, const std::string& a4) {
+void p3::eventHook::run_hook(const std::string& event, const std::string& a2, const std::string& a3, const std::string& a4) {
 	for (auto c : callbacks) {
 		c(event, a2, a3, a4);
 	}
+
+	if (command.empty()) {
+		return;
+	}
+
 	int pid = fork();
 	if (pid == 0) {
 		execl(

src/eventhook.h

@@ -59,11 +59,11 @@ namespace p3 {
 			
 			explicit eventHook(config& c, phonebook& p);
 
-			void run_hook(std::string event, const std::string& a2 = "", const std::string& a3 = "", const std::string& a4 = "");
-			void run_call_hook(std::string event, int call_id = 0, std::string nr = "", std::string data = "");
+			void run_hook(const std::string& event, const std::string& a2 = "", const std::string& a3 = "", const std::string& a4 = "");
+			void run_call_hook(const std::string& event, int call_id = 0, const std::string& nr = "", const std::string& data = "");
 
-			std::list<callback_type>::iterator register_callback(callback_type callback);
-			void unregister_callback(std::list<callback_type>::iterator id);
+			std::list<callback_type>::iterator register_callback(const callback_type& callback);
+			void unregister_callback(const std::list<callback_type>::iterator& id);
 	};
 
 }