/**
 *  @Comment: WSU - Fall 06 - CS 3830-0
 *  @Title: prj2a.c - Project 2a
 *  @Author:  Vincenzo Maggio
 */

#include <conio.h>
#include <dos.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

static struct myTime
{
  clock_t timeEnter;
  clock_t timeExit;
} userTime;

void InitScreen       ( void);
void Menu             ( void);
void Rulers           ( void);
void UpdateTime       ( void);
void Wait4userinput   ( void);
/**/
void Mygets     ( void);
void Mystrcpy   ( void);
void Mystrcat   ( void);
void Mysprintf  ( void);
void Myscanf    ( void);

void UpdateTime( void)
{
  struct tm *pMyTime;
  time_t aclock;
  time( &aclock);
  pMyTime = localtime( &aclock);
  gotoxy( 1,1);
  printf( "%s", asctime( pMyTime) );
}

void InitScreen( void)
{
  system("cls");
  system("color f0");
}

void Menu( void)
{
  system("cls");
  gotoxy( 27, 2);
  puts("--==]~~~ \01 0xYg3N \01 ~~~[==--");
  puts("\n A. Program 1");
  puts("     1. gets()             2. strcpy()");
  puts("     3. strcat()           4. sprintf()");
  puts("     5. scanf()            0. Exit");
  printf( "\n\n Enter your choice: ");
}

void Wait4userinput( void) { while ( !kbhit()) UpdateTime(); }

void Rulers( void)
{
  gotoxy( 13, 16);
  printf( "0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F\n");
}

void Mygets( void)
{
  static char string[8];
  static char saveMe[17];
  int i;

  for ( i = 0; i < 16; i++)
    saveMe[i] = *( string + i);

  gotoxy( 2, 12);
  printf( "To show a buffer overflow with gets(), a user password is simulated. Buffer is char[8], please enter a password (8 < len < 17) chars long: ");
  gotoxy( 2, 14); printf( "Password: ");
  Wait4userinput();

  gotoxy( 12, 14);
  gets( string);

  Rulers();
  gotoxy( 2, 18); printf("Before:   ");
  for ( i = 0; i < 16; i++)  printf( "%2x ", *(saveMe + i) );
  gotoxy( 2, 19); printf("After :   ");
  for ( i = 0; i < 16; i++)  printf( "%2x ", *(string + i) );
  gotoxy( 33, 20); printf("%c\n", 24);
  printf("    String should stop here   __|  ..but goes further");
  printf("\n\n Hit \"any\" key to continue...");
  Wait4userinput();
  getch();
}

void Mystrcpy( void)
{
  static char userInput[17];
  static char dest[9];
  static char saveMe[17];
  int i;

  memset( dest, '\0', 9);
  for ( i = 0; i < 17; i++)
    saveMe[i] = *( dest + i);
  saveMe[16] = '\0';

  gotoxy( 2, 12);
  printf( "To show a buffer overflow with strcpy(), a user password is simulated. Passowrd is char[8], enter a string 8 < len < 17 chars long: ");
  gotoxy( 2, 14); printf( "Password: ");
  Wait4userinput();

  gotoxy( 12, 14);
  fgets( userInput, 16, stdin);

  strcpy( dest, userInput);

  Rulers();
  gotoxy( 2, 18); printf("Before:   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(saveMe + i) );
  gotoxy( 2, 19); printf("After :   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(dest + i) );
  gotoxy( 33, 20); printf("%c\n", 24);
  printf("    String should stop here   __|  ..but goes further");
  printf("\n\n Hit \"any\" key to continue...");
  Wait4userinput();
  getch();
}

void Mystrcat( void)
{
  static char userInput[17];
  static char saveMe[17];
  static char dest[17];
  int i;

  memset( userInput, '\0', 17);
  memset( saveMe, '\0', 17);
  memset( dest, '\0', 15);

  strcat( dest, "Marcello" );
  strcat( dest, " " );

  for ( i = 0; i < 17; i++)
    saveMe[i] = *( dest + i);

  gotoxy( 2, 12);
  printf( "Buffer overflow with strcat(). First/Last name situation is simulated. 1st name is: Marcello, input last name at least 9 chars long: ");
  gotoxy( 2, 14); printf( "Last Name: ");
  Wait4userinput();

  gotoxy( 13, 14);
  fgets( userInput, 16, stdin);

  strcat( dest, userInput);

  Rulers();
  gotoxy( 2, 18); printf("Before:   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(saveMe + i) );
  gotoxy( 2, 19); printf("After :   ");
  for ( i = 0; i < 18; i++) printf( "%2x ", *(dest + i) );
  gotoxy( 58, 20); printf("%c\n", 24);
  gotoxy( 32, 21);printf( "String should stop here __|  ..but goes further");
  printf("\n Hit \"any\" key to continue...");
  Wait4userinput();
  getch();
}

void Mysprintf( void)
{
  static char lastName[12];
  static char saveMe[17];
  int i;

  memset( lastName, '\0', 12);
  memset( saveMe, '\0', 17);
  for ( i = 0; i < 17; i++)
    saveMe[i] = *( lastName + i);

  gotoxy( 2, 12);
  printf( "Buffer overflow with sprintf(). Last name buffer is 12 chars long, here we try\nto stuff in it \"Pareto-Kuffstein\" that is 16 chars long.");
  sprintf( lastName, "Pareto-Kuffstein");

  Rulers();
  gotoxy( 2, 18); printf("Before:   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(saveMe + i) );
  gotoxy( 2, 19); printf("After :   ");
  for ( i = 0; i < 12; i++) printf( "%2x ", *(lastName + i) );

  gotoxy( 46, 20); printf("%c\n", 24);
  gotoxy( 20, 21);printf( "String should stop here __|  ..but goes further. The string\nBefore, which was made of 16 zeroes, now contains \"tein\"");
  printf("\n Hit \"any\" key to continue...");
  Wait4userinput();
  getch();
}

void Myscanf( void)
{
  static char dest[12];
  static char saveMe[17];
  int i;

  memset( dest, '\0', 12);
  memset( saveMe, '\0', 17);
  for ( i = 0; i < 17; i++)
    saveMe[i] = *( dest + i);

  gotoxy( 2, 12);
  printf( "Buffer overflow with scanf(). Insert a string (12 < len < 17) chars long");
  gotoxy( 2, 14); printf( "str input: ");
  Wait4userinput();

  gotoxy( 13, 14);
  scanf( "%s", dest);

  Rulers();
  gotoxy( 2, 18); printf("Before:   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(saveMe + i) );
  gotoxy( 2, 19); printf("After :   ");
  for ( i = 0; i < 16; i++) printf( "%2x ", *(dest + i) );

  gotoxy( 46, 20); printf("%c\n", 24);
  gotoxy( 20, 21);printf( "String should stop here __|  ..but goes further. The string\nBefore, which was made of 16 zeroes, is now overflown");
  printf("\n Hit \"any\" key to continue...");
  Wait4userinput();
  getch();
}

/*  ----------------------------------  */
void main( )
{
  char userChoice;

  userTime.timeEnter = clock();
  InitScreen();

LOOP:
  Menu();
  /*  trap  */
  Wait4userinput();

  gotoxy( 21, 10);
  userChoice = getche();
  switch ( userChoice )
  {
    case '1':
      Mygets();
      break;
    case '2':
      Mystrcpy();
      break;
    case '3':
      Mystrcat();
      break;
    case '4':
      Mysprintf();
      break;
    case '5':
      Myscanf();
      break;
    case '0':
      goto EXIT;
    default:
    gotoxy( 2, 12);
    printf("Error: wrong value\n Make a new choice\n\n");
    system("pause");
    goto LOOP;
  }
  goto LOOP;

EXIT:
  userTime.timeExit = clock();
  system("color 0f");
  system("cls");
  printf("\n You have been connected for %g seconds",
     ((userTime.timeExit - userTime.timeEnter) / (double)1000));
  printf("\n Thanks for using Prj2a!\n\n");
  exit( 0);
}