vendor: update sources

```shell
dep ensure -update
```

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/golang.org/x/crypto/ssh/terminal/util.go

@@ -2,7 +2,7 @@
 // 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
+// +build aix darwin dragonfly freebsd linux,!appengine netbsd openbsd
 
 // Package terminal provides support functions for dealing with terminals, as
 // commonly found on UNIX systems.
@@ -17,36 +17,41 @@
 package terminal // import "golang.org/x/crypto/ssh/terminal"
 
 import (
-	"io"
-	"syscall"
-	"unsafe"
+	"golang.org/x/sys/unix"
 )
 
 // State contains the state of a terminal.
 type State struct {
-	termios syscall.Termios
+	termios unix.Termios
 }
 
-// IsTerminal returns true if the given file descriptor is a terminal.
+// IsTerminal returns whether the given file descriptor is a terminal.
 func IsTerminal(fd int) bool {
-	var termios syscall.Termios
-	_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
-	return err == 0
+	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	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 _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
+	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	if err != nil {
 		return nil, err
 	}
 
-	newState := oldState.termios
-	newState.Iflag &^= syscall.ISTRIP | syscall.INLCR | syscall.ICRNL | syscall.IGNCR | syscall.IXON | syscall.IXOFF
-	newState.Lflag &^= syscall.ECHO | syscall.ICANON | syscall.ISIG
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
+	oldState := 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
 	}
 
@@ -56,73 +61,54 @@ func MakeRaw(fd int) (*State, error) {
 // 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) {
-	var oldState State
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
+	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	if err != nil {
 		return nil, err
 	}
 
-	return &oldState, nil
+	return &State{termios: *termios}, nil
 }
 
 // Restore restores the terminal connected to the given file descriptor to a
 // previous state.
 func Restore(fd int, state *State) error {
-	_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0)
-	return err
+	return unix.IoctlSetTermios(fd, ioctlWriteTermios, &state.termios)
 }
 
 // GetSize returns the dimensions of the given terminal.
 func GetSize(fd int) (width, height int, err error) {
-	var dimensions [4]uint16
-
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
+	ws, err := unix.IoctlGetWinsize(fd, unix.TIOCGWINSZ)
+	if err != nil {
 		return -1, -1, err
 	}
-	return int(dimensions[1]), int(dimensions[0]), nil
+	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)
 }
 
 // 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) {
-	var oldState syscall.Termios
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); err != 0 {
+	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	if err != nil {
 		return nil, err
 	}
 
-	newState := oldState
-	newState.Lflag &^= syscall.ECHO
-	newState.Lflag |= syscall.ICANON | syscall.ISIG
-	newState.Iflag |= syscall.ICRNL
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
+	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 func() {
-		syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0)
-	}()
+	defer unix.IoctlSetTermios(fd, ioctlWriteTermios, termios)
 
-	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
+	return readPasswordLine(passwordReader(fd))
 }