term_unix.go

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
     6  
     7  package term
     8  
     9  import (
    10  	"golang.org/x/sys/unix"
    11  )
    12  
    13  type state struct {
    14  	termios unix.Termios
    15  }
    16  
    17  func isTerminal(fd int) bool {
    18  	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
    19  	return err == nil
    20  }
    21  
    22  func makeRaw(fd int) (*State, error) {
    23  	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
    24  	if err != nil {
    25  		return nil, err
    26  	}
    27  
    28  	oldState := State{state{termios: *termios}}
    29  
    30  	// This attempts to replicate the behaviour documented for cfmakeraw in
    31  	// the termios(3) manpage.
    32  	termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
    33  	termios.Oflag &^= unix.OPOST
    34  	termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN
    35  	termios.Cflag &^= unix.CSIZE | unix.PARENB
    36  	termios.Cflag |= unix.CS8
    37  	termios.Cc[unix.VMIN] = 1
    38  	termios.Cc[unix.VTIME] = 0
    39  	if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, termios); err != nil {
    40  		return nil, err
    41  	}
    42  
    43  	return &oldState, nil
    44  }
    45  
    46  func getState(fd int) (*State, error) {
    47  	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
    48  	if err != nil {
    49  		return nil, err
    50  	}
    51  
    52  	return &State{state{termios: *termios}}, nil
    53  }
    54  
    55  func restore(fd int, state *State) error {
    56  	return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
    57  }
    58  
    59  func getSize(fd int) (width, height int, err error) {
    60  	ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
    61  	if err != nil {
    62  		return 0, 0, err
    63  	}
    64  	return int(ws.Col), int(ws.Row), nil
    65  }
    66  
    67  // passwordReader is an io.Reader that reads from a specific file descriptor.
    68  type passwordReader int
    69  
    70  func (r passwordReader) Read(buf []byte) (int, error) {
    71  	return unix.Read(int(r), buf)
    72  }
    73  
    74  func readPassword(fd int) ([]byte, error) {
    75  	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
    76  	if err != nil {
    77  		return nil, err
    78  	}
    79  
    80  	newState := *termios
    81  	newState.Lflag &^= unix.ECHO
    82  	newState.Lflag |= unix.ICANON | unix.ISIG
    83  	newState.Iflag |= unix.ICRNL
    84  	if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, &newState); err != nil {
    85  		return nil, err
    86  	}
    87  
    88  	defer unix.IoctlSetTermios(fd, ioctlWriteTermios, termios)
    89  
    90  	return readPasswordLine(passwordReader(fd))
    91  }
    92
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