/* Program to report possible bootsector VIRUS contamination

   This program is designed to sit in your AUTO folder. It simply reads the
boot sector of your disk and checks to see is it is executable by TOS.

  By	David Mace			This program is on the Public Domain
	PSC 2 Box 10233			If you find it useful and feel guilty,
	APO San Francisco, CA		send me money to make yourself feel
			96367		better. I don't mind a bit.

  Written July 20, 1989

*/

#include <osbind.h>
#include <linea.h>

alert(string)
	char *string;
{
int r;
	r=Getrez();
	lineaa();
	if (Getrez()!=2)
		{
		Setscreen(-1L,-1L,0);
		Cconws("\007\033c\041");
		}
	Cconws("\033E\n\n\n\n\n\n");
	Cconws(string);
	Cconws("\n\n\n\n\rPress a key to continue...\007");
	Cnecin();
	if (Getrez()!=2)
		{
		Cconws("\033c\040");
		Setscreen(-1L,-1L,r);
		}
	Cconws("\033E");
	linea9();
}

/* Check drive 'D' (A, D=0; B, D=1) for executable bootsector. Returns:
	0=No problem, 1=Executable bootsector, -1=Could not read boot sector */

int check_drive(D)
	int D;
{
unsigned char buf[512];
unsigned int c,cs=0;

	if (Floprd(buf,0L,D,1,0,0,1))
		return(-1);
	else
		{
		/* Calculate check sum */
		cs=0;
		for (c=0;c<512;c+=2)
			cs+=((unsigned)(buf[c]<<8)+buf[c+1]);
		if(cs==0x1234)
			return(1);
		else
			return(0);
		}
}

main()
{
int r;

	Cconws("\033EChecking Drive A-");
	r=check_drive(0);
	switch(r)
		{
		case -1:
			alert("\
       The boot sector on the disk      \n\r\
	     is unreadable!\n\r");
		break;
		case 1:	
			alert("\
       The disk in drive A shows\n\r\
 signs of possible virus contamination.\n\n\r\
    Load a better detection program\n\r\
	 for better diagnosis.\n\r");
		break;
		case 0:
			Cconws(" Bootsector harmless.\n\r");
		break;
		}
	Cconws("\nSTOP THAT @%&#?! DRIVE\n\rBy David J. Mace\n\r");
}