blob: 052e72251d78ea6cbbf2a4dd037f4a9d10eecd27 [file] [log] [blame]
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package term
import (
"io"
"syscall"
"golang.org/x/sys/unix"
)
// State contains the state of a terminal.
type State struct {
termios unix.Termios
}
func isTerminal(fd int) bool {
_, err := unix.IoctlGetTermio(fd, unix.TCGETA)
return err == nil
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, error) {
// see also: http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libast/common/uwin/getpass.c
val, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return nil, err
}
oldState := *val
newState := oldState
newState.Lflag &^= syscall.ECHO
newState.Lflag |= syscall.ICANON | syscall.ISIG
newState.Iflag |= syscall.ICRNL
err = unix.IoctlSetTermios(fd, unix.TCSETS, &newState)
if err != nil {
return nil, err
}
defer unix.IoctlSetTermios(fd, unix.TCSETS, &oldState)
var buf [16]byte
var ret []byte
for {
n, err := syscall.Read(fd, buf[:])
if err != nil {
return nil, err
}
if n == 0 {
if len(ret) == 0 {
return nil, io.EOF
}
break
}
if buf[n-1] == '\n' {
n--
}
ret = append(ret, buf[:n]...)
if n < len(buf) {
break
}
}
return ret, nil
}
// MakeRaw puts the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
// see http://cr.illumos.org/~webrev/andy_js/1060/
func MakeRaw(fd int) (*State, error) {
termios, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return nil, err
}
oldState := State{termios: *termios}
termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
termios.Oflag &^= unix.OPOST
termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN
termios.Cflag &^= unix.CSIZE | unix.PARENB
termios.Cflag |= unix.CS8
termios.Cc[unix.VMIN] = 1
termios.Cc[unix.VTIME] = 0
if err := unix.IoctlSetTermios(fd, unix.TCSETS, termios); err != nil {
return nil, err
}
return &oldState, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, oldState *State) error {
return unix.IoctlSetTermios(fd, unix.TCSETS, &oldState.termios)
}
// GetState returns the current state of a terminal which may be useful to
// restore the terminal after a signal.
func GetState(fd int) (*State, error) {
termios, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return nil, err
}
return &State{termios: *termios}, nil
}
// GetSize returns the dimensions of the given terminal.
func GetSize(fd int) (width, height int, err error) {
ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
if err != nil {
return 0, 0, err
}
return int(ws.Col), int(ws.Row), nil
}