getpasswd functionality in Go?

Question

Would like to be able to take password entry from the stdin console, but, of course, without echoing what the user types.

Is there something comparable to getpasswd functionality in Go? (Google's Go language)

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

Answer 1

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

Answer 2

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.

Answer 3

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
}