tty: Make termios and winsize being optional params

The dangling slave peers might have no data associate
with them if master peer is closed and link is hanging
up. Thus make this parameters optional to not blow the
image with data which never will be used.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

protobuf/tty.proto

@@ -47,9 +47,9 @@ message tty_info_entry {
 	 */
 	required uint32			rdev		=  8;
 
-	required termios_entry		termios		=  9;
-	required termios_entry		termios_locked	= 10;
-	required winsize_entry		winsize		= 11;
+	optional termios_entry		termios		=  9;
+	optional termios_entry		termios_locked	= 10;
+	optional winsize_entry		winsize		= 11;
 
 	/*
 	 * These are optional fields which presense depends on

tty.c

@@ -412,20 +412,26 @@ static int restore_tty_params(int fd, struct tty_info *info)
 	 * never be extended.
 	 */
 
+	if (info->tie->termios_locked) {
 		memzero(&t, sizeof(t));
 		termios_copy(&t, info->tie->termios_locked);
 		if (ioctl(fd, TIOCSLCKTRMIOS, &t) < 0)
 			goto err;
+	}
 
+	if (info->tie->termios) {
 		memzero(&t, sizeof(t));
 		termios_copy(&t, info->tie->termios);
 		if (ioctl(fd, TCSETS, &t) < 0)
 			goto err;
+	}
 
+	if (info->tie->winsize) {
 		memzero(&w, sizeof(w));
 		winsize_copy(&w, info->tie->winsize);
 		if (ioctl(fd, TIOCSWINSZ, &w) < 0)
 			goto err;
+	}
 
 	return 0;
 err:
@@ -632,7 +638,7 @@ static int tty_setup_slavery(void)
 
 static int veirfy_termios(u32 id, TermiosEntry *e)
 {
-	if (e->n_c_cc < TERMIOS_NCC) {
+	if (e && e->n_c_cc < TERMIOS_NCC) {
 		pr_err("pty ID %#x n_c_cc (%d) has wrong value\n",
 		       id, (int)e->n_c_cc);
 		return -1;