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/*
* Copyright (c) 2012 Chris Howey
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package gopass
import (
"errors"
"fmt"
"io"
"os"
)
type FdReader interface {
io.Reader
Fd() uintptr
}
var defaultGetCh = func(r io.Reader) (byte, error) {
buf := make([]byte, 1)
if n, err := r.Read(buf); n == 0 || err != nil {
if err != nil {
return 0, err
}
return 0, io.EOF
}
return buf[0], nil
}
var (
maxLength = 512
ErrInterrupted = errors.New("interrupted")
ErrMaxLengthExceeded = fmt.Errorf("maximum byte limit (%v) exceeded", maxLength)
// Provide variable so that tests can provide a mock implementation.
getch = defaultGetCh
)
// getPasswd returns the input read from terminal.
// If prompt is not empty, it will be output as a prompt to the user
// If masked is true, typing will be matched by asterisks on the screen.
// Otherwise, typing will echo nothing.
func getPasswd(prompt string, masked bool, r FdReader, w io.Writer) ([]byte, error) {
var err error
var pass, bs, mask []byte
if masked {
bs = []byte("\b \b")
mask = []byte("*")
}
if isTerminal(r.Fd()) {
if oldState, err := makeRaw(r.Fd()); err != nil {
return pass, err
} else {
defer func() {
restore(r.Fd(), oldState)
fmt.Fprintln(w)
}()
}
}
if prompt != "" {
fmt.Fprint(w, prompt)
}
// Track total bytes read, not just bytes in the password. This ensures any
// errors that might flood the console with nil or -1 bytes infinitely are
// capped.
var counter int
for counter = 0; counter <= maxLength; counter++ {
if v, e := getch(r); e != nil {
err = e
break
} else if v == 127 || v == 8 {
if l := len(pass); l > 0 {
pass = pass[:l-1]
fmt.Fprint(w, string(bs))
}
} else if v == 13 || v == 10 {
break
} else if v == 3 {
err = ErrInterrupted
break
} else if v != 0 {
pass = append(pass, v)
fmt.Fprint(w, string(mask))
}
}
if counter > maxLength {
err = ErrMaxLengthExceeded
}
return pass, err
}
// GetPasswd returns the password read from the terminal without echoing input.
// The returned byte array does not include end-of-line characters.
func GetPasswd() ([]byte, error) {
return getPasswd("", false, os.Stdin, os.Stdout)
}
// GetPasswdMasked returns the password read from the terminal, echoing asterisks.
// The returned byte array does not include end-of-line characters.
func GetPasswdMasked() ([]byte, error) {
return getPasswd("", true, os.Stdin, os.Stdout)
}
// GetPasswdPrompt prompts the user and returns the password read from the terminal.
// If mask is true, then asterisks are echoed.
// The returned byte array does not include end-of-line characters.
func GetPasswdPrompt(prompt string, mask bool, r FdReader, w io.Writer) ([]byte, error) {
return getPasswd(prompt, mask, r, w)
}
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