text: /*
     Copyright The containerd Authors.
  
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
  
         http://www.apache.org/licenses/LICENSE-2.0
  
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
  */
  
  package console
  
  import (
  	"fmt"
  	"os"
  
  	"golang.org/x/sys/unix"
  )
  
  const (
  	cmdTcGet = unix.TIOCGETA
  	cmdTcSet = unix.TIOCSETA
  )
  
  // unlockpt unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by f.
  // unlockpt should be called before opening the slave side of a pty.
  // This does not exist on FreeBSD, it does not allocate controlling terminals on open
  func unlockpt(f *os.File) error {
  	return nil
  }
  
  // ptsname retrieves the name of the first available pts for the given master.
  func ptsname(f *os.File) (string, error) {
  	n, err := unix.IoctlGetInt(int(f.Fd()), unix.TIOCGPTN)
  	if err != nil {
  		return "", err
  	}
  	return fmt.Sprintf("/dev/pts/%d", n), nil
  }
  