/mandos/release

#define _GNU_SOURCE		/* getline() */

#define _FORTIFY_SOURCE 2

#include <termios.h> 		/* struct termios, tcsetattr(),

				   TCSAFLUSH, tcgetattr(), ECHO */

#include <unistd.h>		/* struct termios, tcsetattr(),

				   STDIN_FILENO, TCSAFLUSH,

				   tcgetattr(), ECHO */

#include <signal.h>		/* sig_atomic_t, raise(), struct

				   sigaction, sigemptyset(),

				   sigaction(), sigaddset(), SIGINT,

				   SIGQUIT, SIGHUP, SIGTERM */

#include <stddef.h>		/* NULL, size_t */

#include <sys/types.h>		/* ssize_t */

#include <stdlib.h>		/* EXIT_SUCCESS, EXIT_FAILURE */

#include <stdio.h>		/* fprintf(), stderr, getline(),

				   stdin, feof(), perror(), fputc(),

				   stdout */

#include <errno.h>		/* errno, EINVAL */

#include <iso646.h>		/* or, not */

#include <stdbool.h>		/* bool, false, true */

volatile bool quit_now = false;

void termination_handler(int signum){

  quit_now = true;

}

int main(int argc, char **argv){

  ssize_t ret = -1;

  size_t n;

  struct termios t_new, t_old;

  char *buffer = NULL;

  int status = EXIT_SUCCESS;

  struct sigaction old_action,

    new_action = { .sa_handler = termination_handler,

		   .sa_flags = 0 };

  if (tcgetattr(STDIN_FILENO, &t_old) != 0){

    return EXIT_FAILURE;

  }

  sigemptyset(&new_action.sa_mask);

  sigaddset(&new_action.sa_mask, SIGINT);

  sigaddset(&new_action.sa_mask, SIGQUIT);

  sigaddset(&new_action.sa_mask, SIGHUP);

  sigaddset(&new_action.sa_mask, SIGTERM);

  sigaction(SIGINT, NULL, &old_action);

  if (old_action.sa_handler != SIG_IGN)

    sigaction(SIGINT, &new_action, NULL);

  sigaction(SIGQUIT, NULL, &old_action);

  if (old_action.sa_handler != SIG_IGN)

    sigaction(SIGQUIT, &new_action, NULL);

  sigaction(SIGHUP, NULL, &old_action);

  if (old_action.sa_handler != SIG_IGN)

    sigaction(SIGHUP, &new_action, NULL);

  sigaction(SIGTERM, NULL, &old_action);

  if (old_action.sa_handler != SIG_IGN)

    sigaction(SIGTERM, &new_action, NULL);

  t_new = t_old;

  t_new.c_lflag &= ~ECHO;

  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_new) != 0){

    perror("tcsetattr-echo");

    return EXIT_FAILURE;

  }

  while(true){

    if (quit_now){

      status = EXIT_FAILURE;

      break;

    }

    fprintf(stderr, "Password: ");

    ret = getline(&buffer, &n, stdin);

    if (ret > 0){

      fprintf(stdout, "%s", buffer);

      status = EXIT_SUCCESS;

      break;

    }

    // ret == 0 makes no other sence than to retry to read from stdin

    if (ret < 0){

      if (errno != EINTR and not feof(stdin)){

	perror("getline");

	status = EXIT_FAILURE;

	break;

      }

    }

    fputc('\n', stderr);

  }

  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &t_old) != 0){

    perror("tcsetattr+echo");

  }

  return status;

}