source: code/trunk/vendor/golang.org/x/term/term_unix.go@ 822

// 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.

//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos

package term

import (
        "golang.org/x/sys/unix"
)

type state struct {
        termios unix.Termios
}

func isTerminal(fd int) bool {
        _, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
        return err == nil
}

func makeRaw(fd int) (*State, error) {
        termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
        if err != nil {
                return nil, err
        }

        oldState := State{state{termios: *termios}}

        // This attempts to replicate the behaviour documented for cfmakeraw in
        // the termios(3) manpage.
        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, ioctlWriteTermios, termios); err != nil {
                return nil, err
        }

        return &oldState, nil
}

func getState(fd int) (*State, error) {
        termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
        if err != nil {
                return nil, err
        }

        return &State{state{termios: *termios}}, nil
}

func restore(fd int, state *State) error {
        return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
}

func getSize(fd int) (width, height int, err error) {
        ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
        if err != nil {
                return -1, -1, err
        }
        return int(ws.Col), int(ws.Row), nil
}

// passwordReader is an io.Reader that reads from a specific file descriptor.
type passwordReader int

func (r passwordReader) Read(buf []byte) (int, error) {
        return unix.Read(int(r), buf)
}

func readPassword(fd int) ([]byte, error) {
        termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
        if err != nil {
                return nil, err
        }

        newState := *termios
        newState.Lflag &^= unix.ECHO
        newState.Lflag |= unix.ICANON | unix.ISIG
        newState.Iflag |= unix.ICRNL
        if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, &newState); err != nil {
                return nil, err
        }

        defer unix.IoctlSetTermios(fd, ioctlWriteTermios, termios)

        return readPasswordLine(passwordReader(fd))
}