Author: Ian Jackson <iwj@ubuntu.com>
Description:
 Check before call ttyname, so don't coredump in chroots without /proc
 (Closes: #440804).

--- a/pty_termios.c
+++ b/pty_termios.c
@@ -369,6 +369,17 @@
 #define W_OK 02
 #endif
 
+static int ttyname_checked(int fd) {
+	const char *result;
+	result= ttyname(fd);
+	if (!result) {
+		perror("expect: pty_termios: system configuration problem:"
+		       " ttyname() failed");
+		exit(-1);
+	}
+	return result;
+}
+
 int
 exp_getptymaster()
 {
@@ -454,7 +465,7 @@
 	master = open("/dev/ptc",O_RDWR);
 	if (master >= 0) {
 		/* never fails */
-		slave_name = ttyname(master);
+		slave_name = ttyname_checked(master);
 	}
 	exp_pty_slave_name = slave_name;
 	return(master);
@@ -475,7 +486,7 @@
 		close(slave);
 		return -1;
 	}
-	strcpy(slave_name, ttyname(slave));
+	strcpy(slave_name, ttyname_checked(slave));
 	exp_pty_slave_name = slave_name;
 	close(slave);
 	return master;