kconfig: handle SIGINT in menuconfig

I recently got bitten in the ass when pressing Ctrl-C and lost all my current
configuration changes. This patch captures SIGINT and allows the user to save
any changes.

Some code refactoring was made in order to handle the exit behavior.
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>

scripts/kconfig/mconf.c

@@ -15,6 +15,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
+#include <signal.h>
 #include <unistd.h>
 #include <locale.h>
 
@@ -272,6 +273,7 @@ static struct menu *current_menu;
 static int child_count;
 static int single_menu_mode;
 static int show_all_options;
+static int saved_x, saved_y;
 
 static void conf(struct menu *menu);
 static void conf_choice(struct menu *menu);
@@ -792,9 +794,54 @@ static void conf_save(void)
 	}
 }
 
+static int handle_exit(void)
+{
+	int res;
+
+	dialog_clear();
+	if (conf_get_changed())
+		res = dialog_yesno(NULL,
+				   _("Do you wish to save your new configuration ?\n"
+				     "<ESC><ESC> to continue."),
+				   6, 60);
+	else
+		res = -1;
+
+	end_dialog(saved_x, saved_y);
+
+	switch (res) {
+	case 0:
+		if (conf_write(filename)) {
+			fprintf(stderr, _("\n\n"
+					  "Error while writing of the configuration.\n"
+					  "Your configuration changes were NOT saved."
+					  "\n\n"));
+			return 1;
+		}
+		/* fall through */
+	case -1:
+		printf(_("\n\n"
+			 "*** End of the configuration.\n"
+			 "*** Execute 'make' to start the build or try 'make help'."
+			 "\n\n"));
+		res = 0;
+		break;
+	default:
+		fprintf(stderr, _("\n\n"
+				  "Your configuration changes were NOT saved."
+				  "\n\n"));
+	}
+
+	return res;
+}
+
+static void sig_handler(int signo)
+{
+	exit(handle_exit());
+}
+
 int main(int ac, char **av)
 {
-	int saved_x, saved_y;
 	char *mode;
 	int res;
 
@@ -802,6 +849,8 @@ int main(int ac, char **av)
 	bindtextdomain(PACKAGE, LOCALEDIR);
 	textdomain(PACKAGE);
 
+	signal(SIGINT, sig_handler);
+
 	conf_parse(av[1]);
 	conf_read(NULL);
 
@@ -823,40 +872,9 @@ int main(int ac, char **av)
 	set_config_filename(conf_get_configname());
 	do {
 		conf(&rootmenu);
-		dialog_clear();
-		if (conf_get_changed())
-			res = dialog_yesno(NULL,
-					   _("Do you wish to save your "
-					     "new configuration?\n"
-					     "<ESC><ESC> to continue."),
-					   6, 60);
-		else
-			res = -1;
+		res = handle_exit();
 	} while (res == KEY_ESC);
-	end_dialog(saved_x, saved_y);
-
-	switch (res) {
-	case 0:
-		if (conf_write(filename)) {
-			fprintf(stderr, _("\n\n"
-				"Error while writing of the configuration.\n"
-				"Your configuration changes were NOT saved."
-				"\n\n"));
-			return 1;
-		}
-		/* fall through */
-	case -1:
-		printf(_("\n\n"
-			"*** End of the configuration.\n"
-			"*** Execute 'make' to start the build or try 'make help'."
-			"\n\n"));
-		break;
-	default:
-		fprintf(stderr, _("\n\n"
-			"Your configuration changes were NOT saved."
-			"\n\n"));
-	}
 
-	return 0;
+	return res;
 }