mirror of
https://gogs.blitter.com/RLabs/xs
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136 lines
3.6 KiB
Go
136 lines
3.6 KiB
Go
// +build linux
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package xs
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import (
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"errors"
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"io"
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unix "golang.org/x/sys/unix"
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)
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/* -------------
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* minimal terminal APIs brought in from ssh/terminal
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* (they have no real business being there as they aren't specific to
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* ssh, but as of Go v1.10, late 2019, core go stdlib hasn't yet done
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* the planned terminal lib reorgs.)
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* ------------- */
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// From github.com/golang/crypto/blob/master/ssh/terminal/util_linux.go
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const ioctlReadTermios = unix.TCGETS
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const ioctlWriteTermios = unix.TCSETS
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// From github.com/golang/crypto/blob/master/ssh/terminal/util.go
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// State contains the state of a terminal.
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type State struct {
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termios unix.Termios
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}
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// MakeRaw put the terminal connected to the given file descriptor into raw
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// mode and returns the previous state of the terminal so that it can be
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// restored.
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func MakeRaw(fd int) (*State, error) {
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termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
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if err != nil {
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return nil, err
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}
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oldState := State{termios: *termios}
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// This attempts to replicate the behaviour documented for cfmakeraw in
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// the termios(3) manpage.
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termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
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termios.Oflag &^= unix.OPOST
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termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG | unix.IEXTEN
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termios.Cflag &^= unix.CSIZE | unix.PARENB
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termios.Cflag |= unix.CS8
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termios.Cc[unix.VMIN] = 1
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termios.Cc[unix.VTIME] = 0
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if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, termios); err != nil {
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return nil, err
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}
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return &oldState, nil
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}
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// GetState returns the current state of a terminal which may be useful to
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// restore the terminal after a signal.
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func GetState(fd int) (*State, error) {
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termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
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if err != nil {
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return nil, err
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}
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return &State{termios: *termios}, nil
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}
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// Restore restores the terminal connected to the given file descriptor to a
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// previous state.
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func Restore(fd int, state *State) error {
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if state != nil {
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return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
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} else {
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return errors.New("nil State")
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}
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}
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// ReadPassword reads a line of input from a terminal without local echo. This
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// is commonly used for inputting passwords and other sensitive data. The slice
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// returned does not include the \n.
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func ReadPassword(fd int) ([]byte, error) {
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termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
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if err != nil {
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return nil, err
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}
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newState := *termios
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newState.Lflag &^= unix.ECHO
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newState.Lflag |= unix.ICANON | unix.ISIG
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newState.Iflag |= unix.ICRNL
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if err := unix.IoctlSetTermios(fd, ioctlWriteTermios, &newState); err != nil {
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return nil, err
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}
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defer func() {
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_ = unix.IoctlSetTermios(fd, ioctlWriteTermios, termios) // nolint: gosec
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}()
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return readPasswordLine(passwordReader(fd))
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}
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// passwordReader is an io.Reader that reads from a specific file descriptor.
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type passwordReader int
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func (r passwordReader) Read(buf []byte) (int, error) {
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return unix.Read(int(r), buf)
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}
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// readPasswordLine reads from reader until it finds \n or io.EOF.
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// The slice returned does not include the \n.
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// readPasswordLine also ignores any \r it finds.
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func readPasswordLine(reader io.Reader) ([]byte, error) {
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var buf [1]byte
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var ret []byte
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for {
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n, err := reader.Read(buf[:])
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if n > 0 {
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switch buf[0] {
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case '\n':
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return ret, nil
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case '\r':
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// remove \r from passwords on Windows
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default:
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ret = append(ret, buf[0])
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}
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continue
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}
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if err != nil {
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if err == io.EOF && len(ret) > 0 {
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return ret, nil
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}
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return ret, err
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}
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}
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}
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