tty: Add get- ioctls to fetch tty status v3
For checkpoint/restore we need to know if tty has
exclusive or packet mode set, as well as if pty
is currently locked. Just to be able to restore
this characteristics.
For this sake the following ioctl codes are introduced
- TIOCGPKT to get packet mode state
- TIOCGPTLCK to get Pty locked state
- TIOCGEXCL to get Exclusive mode state
Note this ioctls are a bit unsafe in terms of data
obtained consistency. The tty characteristics might
be changed right after ioctl complete. Keep it in
mind and use this ioctl carefully.
v2:
- Use TIOC prefix for ioctl codes (by jslaby@)
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Pavel Emelyanov <xemul@parallels.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index a3eba7f..739ea86 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2687,6 +2687,11 @@
case TIOCNXCL:
clear_bit(TTY_EXCLUSIVE, &tty->flags);
return 0;
+ case TIOCGEXCL:
+ {
+ int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
+ return put_user(excl, (int __user *)p);
+ }
case TIOCNOTTY:
if (current->signal->tty != tty)
return -ENOTTY;