how to mask password in c?

Question

In C, I want to display every single character that the user type as * (Ex, Please type in your password: *)

I'm searching around but can't be able to find a solution for this. Does anybody know a good way?

Answer 1

Do it manually; Read input one character at a time with for example getch() in conio, and print a * for each.

Answer 2

Take a look at the ncurses library. It's a very liberally licensed library with a huge amount of functionality on a large variety of systems. I haven't used it very much, so I'm not sure exactly which functions you'd want to call, but if take a look at the documentation, I'm sure you'll find what you want.

Answer 3

See my code. it works on my FC9 x86_64 system:

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>

int main(int argc, char **argv)
{
        char passwd[16];
        char *in = passwd;
        struct termios  tty_orig;
        char c;
        tcgetattr( STDIN_FILENO, &tty_orig );
        struct termios  tty_work = tty_orig;

        puts("Please input password:");
        tty_work.c_lflag &= ~( ECHO | ICANON );  // | ISIG );
        tty_work.c_cc[ VMIN ]  = 1;
        tty_work.c_cc[ VTIME ] = 0;
        tcsetattr( STDIN_FILENO, TCSAFLUSH, &tty_work );

        while (1) {
                if (read(STDIN_FILENO, &c, sizeof c) > 0) {
                        if ('\n' == c) {
                                break;
                        }
                        *in++ = c;
                        write(STDOUT_FILENO, "*", 1);
                }
        }

        tcsetattr( STDIN_FILENO, TCSAFLUSH, &tty_orig );

        *in = '\0';
        fputc('\n', stdout);

        // if you want to see the result: 
        // printf("Got password: %s\n", passwd);

        return 0;
}