/*
* Checksum one more block on all harddrives
*
* Use the adler32() function from libz,
* as it is quick, small, and available.
*/
int
disksum(int blk)
{
struct diskinfo *dip, *dip2;
int st, reprobe = 0;
char *buf;
buf = alloca(DEV_BSIZE);
for(dip = TAILQ_FIRST(&disklist); dip; dip = TAILQ_NEXT(dip, list)){
bios_diskinfo_t *bdi = &dip->bios_info;
/* Skip this disk if it is not a HD or has had an I/O error */
if (!(bdi->bios_number & 0x80) || bdi->flags & BDI_INVALID)
continue;
/* Adler32 checksum */
st = biosd_io(F_READ, bdi, blk, 1, buf);
if (st) {
bdi->flags |= BDI_INVALID;
continue;
}
bdi->checksum = adler32(bdi->checksum, buf, DEV_BSIZE);
for(dip2 = TAILQ_FIRST(&disklist); dip2 != dip;
dip2 = TAILQ_NEXT(dip2, list)){
bios_diskinfo_t *bd = &dip2->bios_info;
if ((bd->bios_number & 0x80) &&
!(bd->flags & BDI_INVALID) &&
bdi->checksum == bd->checksum)
reprobe = 1;
}
}
return (reprobe);
}
static int
Xboot()
{
int dev, part, st;
char buf[DEV_BSIZE], *dest = (void*)0x7c00;
if(cmd.argc != 2) {
printf("machine boot {fd,hd}<0123>[abcd]\n");
printf("Where [0123] is the disk number,"
" and [abcd] is the partition.\n");
return 0;
}
/* Check arg */
if(cmd.argv[1][0] != 'f' && cmd.argv[1][0] != 'h')
goto bad;
if(cmd.argv[1][1] != 'd')
goto bad;
if(cmd.argv[1][2] < '0' || cmd.argv[1][2] > '3')
goto bad;
if((cmd.argv[1][3] < 'a' || cmd.argv[1][3] > 'd') && cmd.argv[1][3] != '\0')
goto bad;
printf("Booting from %s ", cmd.argv[1]);
dev = (cmd.argv[1][0] == 'h')?0x80:0;
dev += (cmd.argv[1][2] - '0');
part = (cmd.argv[1][3] - 'a');
if (part > 0)
printf("[%x,%d]\n", dev, part);
else
printf("[%x]\n", dev);
/* Read boot sector from device */
st = biosd_io(F_READ, dev, 0, 0, 0, 1, buf);
if(st) goto bad;
/* Frob boot flag in buffer from HD */
if((dev & 0x80) && (part > 0)){
int i, j;
for(i = 0, j = DOSPARTOFF; i < 4; i++, j += 16)
if(part == i)
buf[j] |= 0x80;
else
buf[j] &= ~0x80;
}
/* Load %dl, ljmp */
bcopy(buf, dest, DEV_BSIZE);
bootbuf(dest, dev);
bad:
printf("Invalid device!\n");
return 0;
}
