reset terminal state on termination

us.c

@@ -97,6 +97,17 @@ static int get_config(struct config **, int *);
 
 extern char **environ;
 char *config_file = "/etc/us.conf";
+int tty_fd = STDOUT_FILENO;
+struct termios tio_before = {0};
+
+void int_handler(int signum)
+{
+	(void)signum;
+	if (tio_before.c_iflag || tio_before.c_oflag || tio_before.c_iflag)
+		tcsetattr(tty_fd, TCSANOW, &tio_before);
+	putchar('\n');
+	exit(signum);
+}
 
 int main(int argc, char *argv[])
 {
@@ -106,6 +117,24 @@ int main(int argc, char *argv[])
 	struct user_info t_gr_info = {0}, t_pw_info = {0};
 	int opt, err;
 	int shellflag = 0, envflag = 0, askpass = 0;
+
+	/* Save the terminal setup, don't fail since we don't know if we'll
+	 * need it, save it because some shells don't reset termios upon
+	 * program exit, if we don't reset it after a SIGINT or SIGTERM then
+	 * the controlling terminal will be stuck in no echo */
+	if (tcgetattr(tty_fd, &tio_before) == -1) {
+		tio_before.c_iflag = 0;
+		tio_before.c_oflag = 0;
+		tio_before.c_cflag = 0;
+	}
+	struct sigaction action;
+	memset(&action, 0, sizeof(action));
+	action.sa_handler = int_handler;
+	if (sigaction(SIGINT, &action, NULL) == -1)
+		die("Error setting interrupt handler:");
+	if (sigaction(SIGTERM, &action, NULL) == -1)
+		die("Error setting interrupt handler:");
+	
 	while ((opt = getopt(argc, argv, "Au:g:C:seh")) != -1) {
 		switch (opt) {
 		case 'A':
@@ -487,7 +516,6 @@ static int authenticate(uid_t uid, int ask, int persist)
 	struct passwd *pw = getpwuid(uid);
 	char *hash_p, hash[MAX_HASH];
 	char *p = pw->pw_passwd;
-	int tty_fd = STDOUT_FILENO;
 
 	if (!strcmp(p, "x") || *p == '*' || *p == '!') {
 #if defined(__linux__)
@@ -519,7 +547,7 @@ static int authenticate(uid_t uid, int ask, int persist)
 	int fd = STDIN_FILENO;
 	char *askpass = getenv("US_ASKPASS");
 	char pass[PASS_MAX] = {0};
-	struct termios tio_before, tio_pass;
+	struct termios tio_pass;
 	if (ask && askpass) {
 		pid_t pid, parent = getpid();
 		int pipefd[2];