tty: add TIOCVHANGUP to allow clean tty shutdown of all ttys

This is useful for system management software so that it can kick
off things like gettys and everything that's started from a tty,
before we reuse it from/for something else or shut it down.

Without this ioctl it would have to temporarily become the owner of
the tty, then call vhangup() and then give it up again.

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 20a862a2a0c2..8ef2d69470ec 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2626,6 +2626,11 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                 return put_user(tty->ldisc->ops->num, (int __user *)p);
         case TIOCSETD:
                 return tiocsetd(tty, p);
+        case TIOCVHANGUP:
+                if (!capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+                tty_vhangup(tty);
+                return 0;
         case TIOCGDEV:
         {
                 unsigned int ret = new_encode_dev(tty_devnum(real_tty));