#include<dos.h>
#include<dir.h>
#include<string.h>
void main()

{
int virus_found,more;

virus_found=RAM_Test();

if(virus_found)
{

Reset_INT13();

clean_Disk('F') ;

}

while(1)
{
printf("\n\nMore diskette to clean ? Y/N");

more=toupper(getch());

while(more!='Y' &&more!='N')
more=toupper(getch());

if(more=='N') exit(0);
clean_Disk(more);

}
}

/* End of program */

/* Routine to check Ram for virus */

RAM_Test()
{
unsigned int vseg,voff;

void interrupt(*v)(void);

printf("\n\n RAM checking____");

v=getvect(109);
vseg=FP_SEG(v);
voff=FP_OFF(v);
if(vseg!=0x0 && voff=0x0)
{
printf("virus detected :-");
putch(7);return(1);
}
else
{
printf("ok\n\n");
putch(7);putch(7);return(0);
}
}
/*end of routine ram test*/

/*ROUTINE TO RESETINT 13H*/
Reset_INT13()
{
unsigned int vseg,voff;

void interrupt(*v)(void);
v=getvect(109);
vseg=FP_SEG(v);voff=FP_OFF(v);
poke(0,76,voff);poke(0,78,vseg);
printf("disabled\n");
}
/*end of routine Reset_INT13*/

/*Routine to clean diskette*/

clean_Disk(next)
char next;
{
clean_Boot_sector(next);
clean_Data_Area();
change_Label();
}
/* end of routine clean disk*/

clean_Boot_sector(next_disk)
char next_disk;
{
int ans,i,True;
static void *buf[512];
char virus[6],ashar[]="ashar",brain[]="Brain";
if(next_disk=='F')
True=1;
else True=0;
while(True)
{
printf("\ninsert dos diskettein drive A____WAITING\n");
ans=getch();
ans=absread(0,1,0,buf);
virus=ashar;
ans=chkboot(buf,&virus);
virus=brain;
ans=ans&&chkboot(buf,&virus);
if(!ans)
{
printf("\nBoot sector infected with virus\n") ;
}
else
break;
}
printf("\n insert infected disk in drive A_________ waiting\n\n\n");
ans=getch();
ans=abswrite(0,1,0,buf);
if(ans)
printf("\n unable to clean disk\n");
}

/*end of routine clean boot record*/

/*subroutine to check virus*/
/*boot routine*/
chkboot(str,name)
char str[512],name[6];
{
int i,k;
for(i=0,k=0;i<512;i++)
if(str[i]==name[k])
{
k++;
if(k==5)
return(0);
else
continue;
}
else
k=0;
return(1);
}

/*end of sub routine chk boot*/

/*routine to clean virus*/
/* executive routine*/

clean_Data_Area()
{
int i,j;
float rj;
unsigned int fat_off,fat_dmp;
unsigned dmp_sav;
unsigned char fatbuf[1024],b1,b2;
absread(0,2,1,fatbuf);j=0;

for(i=2;i<355;i++)
{
rj=1.5*i;
fat_off=rj;
b2=fatbuf[fat_off+1];
b1=fatbuf[fat_off];
fat_dmp=b2;
fat_dmp=fat_dmp<<8;
fat_dmp=fat_dmp+b1;
dmp_sav=fat_dmp;
if(rj==fat_off)
fat_dmp=fat_dmp&0xffff;
else fat_dmp=fat_dmp>>4;
fat_dmp=fat_dmp<<4;
fat_dmp=fat_dmp>>4;
if(fat_dmp==0x0ff7)
{
j++;
if(rj==fat_off)
dmp_sav=dmp_sav&0xf000;
else
dmp_sav=dmp_sav&0x000f;
b2=(dmp_sav&0xff00)>>8;
b1=dmp_sav&0x00ff;
fatbuf[fat_off]=b1;
fatbuf[fat_off+1]=b2;
}
}
if(j)
{
abswrite(0,2,1,fatbuf);
printf("disk cleaned \n\n");
}
}

/*End of routine clean_data_Area*/

/*routine to change volume label */

change_Label()
{
unsigned char buf[512],volb1[11];
int i,llen,lblpos,sno=5;
struct ffblk blk;
i=findfirst("*.*",&blk,0x08);
if(!i)
{
absread(0,1,sno,buf);
lblpos=findlbl(buf);
while(!lblpos){ sno++;absread(0,1,sno,buf);
lblpos=lblpos-0x0b;
for(i=0;i<0x0b;i++)
volb1[i]=buf[lblpos+i];
volb1[i]=0x0b;
printf("volume label is %s \n",volb1);
}
}
else
printf("volume label not defined\n");
printf("enter new label (char):");
scanf("%s",volb1);
if(!i)
{
llen=strlen(volb1);
for(i=0;i<=llen;i++,lblpos++)
buf[lblpos]=volb1[i];
for(;i<0x0b;i++,lblpos++)
buf[lblpos]=' ';
abswrite(0,1,sno,buf);
}else
{
i=_creat(volb1,0x08);
close(i);
}
}
findlbl(source)
unsigned char source[512];
{
int ofset=0x0b;
while(ofset<512){
if(source[ofset]==0x28)
return(ofset);
ofset=ofset+0x020;
}
return(0);
}