Use RAII for terminal settings

nmap.cc

@@ -1899,8 +1899,7 @@ int nmap_main(int argc, char *argv[]) {
   else
     nbase_set_log(fatal, NULL);
 
-
-  tty_init(); // Put the keyboard in raw mode
+  TTYState ttystate; // Put the keyboard in raw mode
 
 #ifdef WIN32
   // Must come after parse_options because of --unprivileged

nmap_tty.cc

@@ -246,6 +246,10 @@ void tty_init()
 
 #endif  //!win32
 
+TTYState::~TTYState() {
+  tty_done();
+}
+
 /* Catches all of the predefined
    keypresses and interpret them, and it will also tell you if you
    should print anything. A value of true being returned means a

nmap_tty.h

@@ -74,4 +74,11 @@ void tty_init();
    calling method should print a status message */
 bool keyWasPressed();
 
+/* RAII object for TTY management */
+class TTYState {
+  public:
+  TTYState() { tty_init(); }
+  ~TTYState(); // calls tty_done()
+};
+
 #endif