-/**
- * pty_open_peer - open the peer of a pty
- * @tty: the peer of the pty being opened
- *
- * Open the cached dentry in tty->link, providing a safe way for userspace
- * to get the slave end of a pty (where they have the master fd and cannot
- * access or trust the mount namespace /dev/pts was mounted inside).
- */
-static struct file *pty_open_peer(struct tty_struct *tty, int flags)
-{
- if (tty->driver->subtype != PTY_TYPE_MASTER)
- return ERR_PTR(-EIO);
- return dentry_open(tty->link->driver_data, flags, current_cred());
-}
-
-static int pty_get_peer(struct tty_struct *tty, int flags)
-{
- int fd = -1;
- struct file *filp = NULL;
- int retval = -EINVAL;
-
- fd = get_unused_fd_flags(0);
- if (fd < 0) {
- retval = fd;
- goto err;
- }
-
- filp = pty_open_peer(tty, flags);
- if (IS_ERR(filp)) {
- retval = PTR_ERR(filp);
- goto err_put;
- }
-
- fd_install(fd, filp);
- return fd;
-
-err_put:
- put_unused_fd(fd);
-err:
- return retval;
-}
-