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// Copyright 2011 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.
// +build darwin dragonfly freebsd linux,!appengine netbsd openbsd solaris
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Putting a terminal into raw mode is the most common requirement:
//
// oldState, err := terminal.MakeRaw(0)
// if err != nil {
// panic(err)
// }
// defer terminal.Restore(0, oldState)
package readline
import (
"io"
"syscall"
)
// State contains the state of a terminal.
type State struct {
termios Termios
}
// IsTerminal returns true if the given file descriptor is a terminal.
func IsTerminal(fd int) bool {
_, err := getTermios(fd)
return err == nil
}
// MakeRaw put 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.
func MakeRaw(fd int) (*State, error) {
var oldState State
if termios, err := getTermios(fd); err != nil {
return nil, err
} else {
oldState.termios = *termios
}
newState := oldState.termios
// This attempts to replicate the behaviour documented for cfmakeraw in
// the termios(3) manpage.
newState.Iflag &^= syscall.IGNBRK | syscall.BRKINT | syscall.PARMRK | syscall.ISTRIP | syscall.INLCR | syscall.IGNCR | syscall.ICRNL | syscall.IXON
// newState.Oflag &^= syscall.OPOST
newState.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG | syscall.IEXTEN
newState.Cflag &^= syscall.CSIZE | syscall.PARENB
newState.Cflag |= syscall.CS8
newState.Cc[syscall.VMIN] = 1
newState.Cc[syscall.VTIME] = 0
return &oldState, setTermios(fd, &newState)
}
// 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 := getTermios(fd)
if err != nil {
return nil, err
}
return &State{termios: *termios}, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func restoreTerm(fd int, state *State) error {
return setTermios(fd, &state.termios)
}
// 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) {
oldState, err := getTermios(fd)
if err != nil {
return nil, err
}
newState := oldState
newState.Lflag &^= syscall.ECHO
newState.Lflag |= syscall.ICANON | syscall.ISIG
newState.Iflag |= syscall.ICRNL
if err := setTermios(fd, newState); err != nil {
return nil, err
}
defer func() {
setTermios(fd, 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
}
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