getpasswd functionality in Go?

Situation:

I want to get a password entry from the stdin console - without echoing what the user types. Is there something开发者_如何学Python comparable to getpasswd functionality in Go?

What I tried:

I tried using syscall.Read, but it echoes what is typed.

The following is one of best ways to get it done. First get term package by go get golang.org/x/term

package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
    "syscall"

    "golang.org/x/term"
)

func main() {
    username, password, _ := credentials()
    fmt.Printf("Username: %s, Password: %s\n", username, password)
}

func credentials() (string, string, error) {
    reader := bufio.NewReader(os.Stdin)

    fmt.Print("Enter Username: ")
    username, err := reader.ReadString('\n')
    if err != nil {
        return "", "", err
    }

    fmt.Print("Enter Password: ")
    bytePassword, err := term.ReadPassword(int(syscall.Stdin))
    if err != nil {
        return "", "", err
    }

    password := string(bytePassword)
    return strings.TrimSpace(username), strings.TrimSpace(password), nil
}

http://play.golang.org/p/l-9IP1mrhA

Just saw a mail in #go-nuts maillist. There is someone who wrote quite a simple go package to be used. You can find it here: https://github.com/howeyc/gopass

It something like that:

package main

import "fmt"
import "github.com/howeyc/gopass"

func main() {
    fmt.Printf("Password: ")
    pass := gopass.GetPasswd()
    // Do something with pass
}

Since Go ~v1.11 there is an official package golang.org/x/term which replaces the deprecated crypto/ssh/terminal. It has, among other things, the function term.ReadPassword.

Example usage:

package main
import (
    "fmt"
    "os"
    "syscall"
    "golang.org/x/term"
)
func main() {
    fmt.Print("Password: ")
    bytepw, err := term.ReadPassword(int(syscall.Stdin))
    if err != nil {
        os.Exit(1)
    }
    pass := string(bytepw)
    fmt.Printf("\nYou've entered: %q\n", pass)
}

I had a similar usecase and the following code snippet works well for me. Feel free to try this if you are still stuck here.

import (
    "fmt"
    "golang.org/x/crypto/ssh/terminal"

)

func main() {
    fmt.Printf("Now, please type in the password (mandatory): ")
    password, _ := terminal.ReadPassword(0)

    fmt.Printf("Password is : %s", password)
}

Of course, you need to install terminal package using go get beforehand.

you can do this by execing stty -echo to turn off echo and then stty echo after reading in the password to turn it back on

Here is a solution that I developed using Go1.6.2 that you might find useful.

It only uses the following standard packages: bufio, fmt, os, strings and syscall. More specifically, it uses syscall.ForkExec() and syscall.Wait4() to invoke stty to disable/enable terminal echo.

I have tested it on Linux and BSD (Mac). It will not work on windows.

// getPassword - Prompt for password. Use stty to disable echoing.
import ( "bufio"; "fmt"; "os"; "strings"; "syscall" )
func getPassword(prompt string) string {
    fmt.Print(prompt)

    // Common settings and variables for both stty calls.
    attrs := syscall.ProcAttr{
        Dir:   "",
        Env:   []string{},
        Files: []uintptr{os.Stdin.Fd(), os.Stdout.Fd(), os.Stderr.Fd()},
        Sys:   nil}
    var ws syscall.WaitStatus

    // Disable echoing.
    pid, err := syscall.ForkExec(
        "/bin/stty",
        []string{"stty", "-echo"},
        &attrs)
    if err != nil {
        panic(err)
    }

    // Wait for the stty process to complete.
    _, err = syscall.Wait4(pid, &ws, 0, nil)
    if err != nil {
        panic(err)
    }

    // Echo is disabled, now grab the data.
    reader := bufio.NewReader(os.Stdin)
    text, err := reader.ReadString('\n')
    if err != nil {
        panic(err)
    }

    // Re-enable echo.
    pid, err = syscall.ForkExec(
        "/bin/stty",
        []string{"stty", "echo"},
        &attrs)
    if err != nil {
        panic(err)
    }

    // Wait for the stty process to complete.
    _, err = syscall.Wait4(pid, &ws, 0, nil)
    if err != nil {
        panic(err)
    }

    return strings.TrimSpace(text)
}

Required launching stty via Go ForkExec() function:

package main

import (
    os      "os"
    bufio   "bufio"
    fmt     "fmt"
    str     "strings"
)

func main() {
    fmt.Println();
    if passwd, err := Getpasswd("Enter password: "); err == nil {
        fmt.Printf("\n\nPassword: '%s'\n",passwd)
    }
}

func Getpasswd(prompt string) (passwd string, err os.Error) {
    fmt.Print(prompt);
    const stty_arg0  = "/bin/stty";
    stty_argv_e_off := []string{"stty","-echo"};
    stty_argv_e_on  := []string{"stty","echo"};
    const exec_cwdir = "";
    fd := []*os.File{os.Stdin,os.Stdout,os.Stderr};
    pid, err := os.ForkExec(stty_arg0,stty_argv_e_off,nil,exec_cwdir,fd);
    if err != nil {
        return passwd, os.NewError(fmt.Sprintf("Failed turning off console echo for password entry:\n\t%s",err))
    }
    rd := bufio.NewReader(os.Stdin);
    os.Wait(pid,0);
    line, err := rd.ReadString('\n');
    if err == nil {
        passwd = str.TrimSpace(line)
    } else {
        err = os.NewError(fmt.Sprintf("Failed during password entry: %s",err))
    }
    pid, e := os.ForkExec(stty_arg0,stty_argv_e_on,nil,exec_cwdir,fd);
    if e == nil {
        os.Wait(pid,0)
    } else if err == nil {
        err = os.NewError(fmt.Sprintf("Failed turning on console echo post password entry:\n\t%s",e))
    }
    return passwd, err
}

Here is a version specific to Linux:

func terminalEcho(show bool) {
    // Enable or disable echoing terminal input. This is useful specifically for
    // when users enter passwords.
    // calling terminalEcho(true) turns on echoing (normal mode)
    // calling terminalEcho(false) hides terminal input.
    var termios = &syscall.Termios{}
    var fd = os.Stdout.Fd()

    if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd,
        syscall.TCGETS, uintptr(unsafe.Pointer(termios))); err != 0 {
        return
    }

    if show {
        termios.Lflag |= syscall.ECHO
    } else {
        termios.Lflag &^= syscall.ECHO
    }

    if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd,
        uintptr(syscall.TCSETS),
        uintptr(unsafe.Pointer(termios))); err != 0 {
        return
    }
}

So to use it:

fmt.Print("password: ")

terminalEcho(false)
var pw string
fmt.Scanln(&pw)
terminalEcho(true)
fmt.Println("")

It's the TCGETS syscall that is linux specific. There are different syscall values for OSX and Windows.

You could also use PasswordPrompt function of https://github.com/peterh/liner package.

Turning off echo before typing and turning on to turn it back on after typing.

Without third library, you can find ways to do with it on unix shown above. But it's difficult on Windows.

You can achieve it by method SetConsoleMode with windows kernel32.dll referring to the accepted answer from C: How to disable echo in windows console?

func GetPassword(prompt string) (err error, text string) {
    var modeOn, modeOff uint32
    stdin := syscall.Handle(os.Stdin.Fd())
    err = syscall.GetConsoleMode(stdin, &modeOn)
    if err != nil {
        return
    }
    modeOff = modeOn &^ 0x0004
    proc := syscall.MustLoadDLL("kernel32").MustFindProc("SetConsoleMode")
    fmt.Print(prompt)
    _, _, _ = proc.Call(uintptr(stdin), uintptr(modeOff))
    _, err = fmt.Scanln(&text)
    if err != nil {
        return
    }
    _, _, _ = proc.Call(uintptr(stdin), uintptr(modeOn))
    fmt.Println()
    return nil, strings.TrimSpace(text)
}

You can get the behavior you want with the Read method from the os.File object (or the os.Stdin variable). The following sample program will read a line of text (terminated with by pressing the return key) but won't echo it until the fmt.Printf call.

package main

import "fmt"
import "os"

func main() {
  var input []byte = make( []byte, 100 );
  os.Stdin.Read( input );
  fmt.Printf( "%s", input );
}

If you want more advanced behavior, you're probably going to have to use the Go C-wrapper utilities and create some wrappers for low-level api calls.