password.cpp

#include <iostream>
#include <string>
#include <stdexcept>

#define _XOPEN_SOURCE
#include <unistd.h>

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

/* 
   Usa a função "crypt" do posix para criar o hash usado no passwd ou no shadow 

   Uses the posix funciton "crypt" to create the same password hash used on passwd and/or shadow
*/

/** Classe para colocar o stdout no modo de entrada de password.
  * Baseado no código exemplo da man page do getpass(3).
  *
  * this class puts the stduot in the password entry mode, based on the sample code on
  * the getpass(3) man page.
  */
class Pass
{
public:
	Pass()
	{
		tcgetattr (1, &old);
		n = old;
		n.c_lflag &= ~ECHO;
		if (tcsetattr (1, TCSAFLUSH, &n) != 0)
			throw std::runtime_error("could not set attr");
	}

	~Pass()
	{
		tcsetattr (1, TCSAFLUSH, &old);
	}
private:
	struct termios old, n;
};

int main()
{
	std::string pass;
	std::string salt;

	std::cout << "passwd : ";
	std::flush(std::cout);

	{
		Pass no_echo;
		std::cin >> pass;
	}


	std::cout << "\nSalt : ";
	std::flush(std::cout);

	std::cin >> salt;

	std::cout << crypt(pass.c_str(), salt.c_str()) << "\n";
}