bios.c

grub4dos-0.4.4-2008- 08-src.zip

			geometry->sectors = fd_geom[d].sectors;
			geometry->cylinders = fd_geom[d].cylinders;
			return 0;
		}
	    }
	}
    }
#endif

#ifndef STAGE1_5
//      if (debug > 0)
//	grub_printf ("Debug: get_diskinfo: AH=41, drive=%x ...", drive);
#endif

#ifndef STAGE1_5
      if (debug > 1)      
	grub_printf (" int13/41(%X),", drive);
#endif
      version = check_int13_extensions (drive);
#ifndef STAGE1_5
      if (debug > 1)      
	grub_printf ("version=%X, ", version);
#endif

#ifndef STAGE1_5
//      if (debug > 0)
//	/* wipe out debug message. */
//	grub_printf ("\r                                                                             \r");
#endif

//      err = 1;
      
      /* It is safe to clear out DRP.  */
      grub_memset (drp, 0, sizeof (struct drive_parameters));

      /* Buggy KT133A(AWARD BIOS 6.00PG) does not return valid version.
       * So we don't check version for now. - Tinybit
       */

      /* PhoenixBIOS 4.0 Revision 6.0 for ZF Micro might understand the
	 greater buffer size for the "get drive parameters" int 13 call in 
	 its own way.  Supposedly the BIOS assumes even bigger space is
	 available and thus corrupts the stack. This is why we specify the  
	 exactly necessary size of 0x42 bytes. */
      drp->size = sizeof (struct drive_parameters) - 16;
	  
#ifndef STAGE1_5
	  if (drive & 0x80)
	  if (debug > 1)
		grub_printf (" int13/48(%X),", drive);
#endif
#if 1
	  if (drive & 0x80)
	    err = biosdisk_int13_extensions (0x4800, drive, drp);
	  else
#endif
	    err = 0;
#ifndef STAGE1_5
	  if (drive & 0x80)
	  if (debug > 1)
		grub_printf ("err=%X, C/H/S=%d/%d/%d, Sector Count/Size=%d/%d, ", err, drp->cylinders, drp->heads, drp->sectors, drp->total_sectors, drp->bytes_per_sector);
#endif
	  if (! err)
	    {
		/* Set the LBA flag.  */
		if (version & 1) /* support functions 42h-44h, 47h-48h */
		{
			flags = BIOSDISK_FLAG_LBA_EXTENSION;
	      
			/* Set the CDROM flag.  */
			if (drp->bytes_per_sector == ISO_SECTOR_SIZE)
				flags |= BIOSDISK_FLAG_CDROM;
		}
		total_sectors = drp->total_sectors;
	    }


#ifndef STAGE1_5
//      if (debug > 0)
//	grub_printf ("Debug: get_diskinfo: AH=08, drive=%x ...", drive);
#endif

#ifndef STAGE1_5
	if (debug > 1)
		grub_printf (" int13/08(%X),", drive);
#endif
	/* Don't pass GEOMETRY directly, but pass each element instead,
		 so that we can change the structure easily.  */
	version = get_diskinfo_standard ((unsigned char)drive, &geometry->cylinders, &geometry->heads, &geometry->sectors);
#ifndef STAGE1_5
	if (debug > 1)
		grub_printf ("version=%X, C/H/S=%d/%d/%d, ", version, geometry->cylinders, geometry->heads, geometry->sectors);
#endif

#ifndef STAGE1_5
//      if (debug > 0)
//	/* wipe out debug message. */
//	grub_printf ("\r                                                                             \r");
#endif

	if (version && err)
		return err; /* When we return with ERROR, we should not change the geometry!! */
      
	geometry->flags = flags;
	geometry->sector_size = (drp->bytes_per_sector ? drp->bytes_per_sector : SECTOR_SIZE);
	if (geometry->cylinders < drp->cylinders)
	    geometry->cylinders = drp->cylinders;
	if (geometry->heads < drp->heads)
	    geometry->heads = drp->heads;
	if (geometry->sectors < drp->sectors)
	    geometry->sectors = drp->sectors;
	if (geometry->heads > 256)
	    geometry->heads = 256;
	if (geometry->sectors * geometry->sector_size > 63 * 512)
	    geometry->sectors = 63 * 512 / geometry->sector_size;
	tmp = (unsigned long long)(geometry->cylinders) *
	      (unsigned long long)(geometry->heads) *
	      (unsigned long long)(geometry->sectors);
	if (total_sectors < tmp)
	    total_sectors = tmp;
	geometry->total_sectors = total_sectors;

#ifndef STAGE1_5
	if (geometry->sector_size != SECTOR_SIZE) /* CD */
		return 0;

	/* workaround for buggy USB-bootable board QDI 848E.
	 * try a further probe in the boot sector.
	 */
	if (debug > 1)
		grub_printf (" int13/02(%X),", drive);
	/* read the boot sector: int 13, AX=0x201, CX=1, DH=0 */
#ifndef STAGE1_5
//      if (debug > 0)
//	grub_printf ("Debug: get_diskinfo: AH=02, drive=%x, C=0, H=0, S=1, nsec=1, segment=5FE0 ...", drive);
#endif

	err = biosdisk_standard (0x02, drive, 0, 0, 1, 1, 0x5FE0/*SCRATCHSEG*/);
#ifndef STAGE1_5
//      if (debug > 0)
//	/* wipe out debug message. */
//	grub_printf ("\r                                                                             \r");
#endif

	if (debug > 1)
		grub_printf ("err=%X, ", err);
	if (err)
	{
		/* try again using LBA */
		if (geometry->flags & BIOSDISK_FLAG_LBA_EXTENSION)
		{
			struct disk_address_packet
			{
				unsigned char length;
				unsigned char reserved;
				unsigned short blocks;
				unsigned long buffer;
				unsigned long long block;

				unsigned char dummy[16];
			} __attribute__ ((packed)) *dap;

			dap = (struct disk_address_packet *)0x580;

			dap->length = 0x10;
			dap->reserved = 0;
			dap->blocks = 1;
			dap->buffer = 0x5FE0/*SCRATCHSEG*/ << 16;
			dap->block = 0;

#ifndef STAGE1_5
//      if (debug > 0)
//	grub_printf ("Debug: get_diskinfo: AH=42, drive=%x, sector=0, nsec=1, segment=5FE0 ...", drive);
#endif

			err = biosdisk_int13_extensions (0x4200, drive, dap);
#ifndef STAGE1_5
//      if (debug > 0)
//	/* wipe out debug message. */
//	grub_printf ("\r                                                                             \r");
#endif

		} /* if (geometry->flags & BIOSDISK_FLAG_LBA_EXTENSION) */
	}

	if (err)
		goto failure_probe_boot_sector;

	/* successfully read boot sector */

	if (drive & 0x80)
	{
		/* hard disk */
		if ((err = probe_mbr((struct master_and_dos_boot_sector *)0x5FE00/*SCRATCHADDR*/, 0, total_sectors, 0)))
		{
			if (debug > 1)
				grub_printf ("\nWarning: Unrecognized partition table for drive %X. Please rebuild it using\na Microsoft-compatible FDISK tool(err=%d). Current C/H/S=%d/%d/%d\n", drive, err, geometry->cylinders, geometry->heads, geometry->sectors);
			goto failure_probe_boot_sector;
		}
		err = (int)"MBR";
	}else{
		/* floppy */
		if (probe_bpb((struct master_and_dos_boot_sector *)0x5FE00/*SCRATCHADDR*/))
		{
#if 0
			/* try INT13/AH=48h here. This could hang on some buggy USB BIOSes. */

			/* It is safe to clear out DRP.  */
			grub_memset (drp, 0, sizeof (struct drive_parameters));
			drp->size = sizeof (struct drive_parameters) - 16;

			if (debug > 0)
				grub_printf ("\nBPB geometry probe failed, so try int13/48(%X), but this could hang on buggy USB BIOSes...", drive);
			err = biosdisk_int13_extensions (0x4800, drive, drp);
			if (debug > 0)
				grub_printf (" err=%X, C/H/S=%d/%d/%d, Sector Count/Size=%d/%d.\n", err, drp->cylinders, drp->heads, drp->sectors, drp->total_sectors, drp->bytes_per_sector);
			if (drp->heads > 0 && drp->heads <= 256 && drp->sectors > 0 && drp->sectors <= 63)
			{
				geometry->sectors = drp->sectors;
				geometry->heads = drp->heads;
				geometry->cylinders = drp->cylinders;
				geometry->total_sectors = drp->cylinders * drp->heads * drp->sectors;
			}
			if (geometry->total_sectors < drp->total_sectors)
			    geometry->total_sectors = drp->total_sectors;
#endif
			goto failure_probe_boot_sector;
		}

		err = (int)"BPB";
	}

	if (drive & 0x80)
	if (probed_cylinders != geometry->cylinders)
	    if (debug > 1)
		grub_printf ("\nWarning: %s cylinders(%d) is not equal to the BIOS one(%d).\n", (char *)err, probed_cylinders, geometry->cylinders);

	geometry->cylinders = probed_cylinders;

	if (probed_heads != geometry->heads)
	    if (debug > 1)
		grub_printf ("\nWarning: %s heads(%d) is not equal to the BIOS one(%d).\n", (char *)err, probed_heads, geometry->heads);

	geometry->heads	= probed_heads;

	if (probed_sectors_per_track != geometry->sectors)
	    if (debug > 1)
		grub_printf ("\nWarning: %s sectors per track(%d) is not equal to the BIOS one(%d).\n", (char *)err, probed_sectors_per_track, geometry->sectors);

	geometry->sectors = probed_sectors_per_track;

	if (probed_total_sectors > total_sectors)
	{
	    if (drive & 0x80)
	    if (debug > 1)
		grub_printf ("\nWarning: %s total sectors(%d) is greater than the BIOS one(%d).\nSome buggy BIOSes could hang when you access sectors exceeding the BIOS limit.\n", (char *)err, probed_total_sectors, total_sectors);
	    geometry->total_sectors	= probed_total_sectors;
	}

	if (drive & 0x80)
	if (probed_total_sectors < total_sectors)
	    if (debug > 1)
		grub_printf ("\nWarning: %s total sectors(%d) is less than the BIOS one(%d).\n", (char *)err, probed_total_sectors, total_sectors);

failure_probe_boot_sector:
	
#ifndef GRUB_UTIL
#if 1
	if (!(geometry->flags & BIOSDISK_FLAG_LBA_EXTENSION))
	{
		err = geometry->heads;
		version = geometry->sectors;

		/* DH non-zero for geometry_tune */
		get_diskinfo_standard (drive | 0x0100, &geometry->cylinders, &geometry->heads, &geometry->sectors);

		if (debug > 0)
		{
		    if (err != geometry->heads)
			grub_printf ("\nNotice: number of heads for drive %X tuned from %d to %d.\n", drive, err, geometry->heads);
		    if (version != geometry->sectors)
			grub_printf ("\nNotice: sectors-per-track for drive %X tuned from %d to %d.\n", drive, version, geometry->sectors);
		}
	}
#endif
#endif

	/* if C/H/S=0/0/0, use a safe default one. */
	if (geometry->sectors == 0)
	{
		if (drive & 0x80)
		{
			/* hard disk */
			geometry->sectors = 63;
		}else{
			/* floppy */
			if (geometry->total_sectors > 5760)
				geometry->sectors = 63;
			else if (geometry->total_sectors > 2880)
				geometry->sectors = 36;
			else
				geometry->sectors = 18;
		}
	}
	if (geometry->heads == 0)
	{
		if (drive & 0x80)
		{
			/* hard disk */
			geometry->heads = 255;
		}else{
			/* floppy */
			if (geometry->total_sectors > 5760)
				geometry->heads = 255;
			else
				geometry->heads = 2;
		}
	}
	if (geometry->cylinders == 0)
	{
		geometry->cylinders = (geometry->total_sectors / geometry->heads / geometry->sectors);
	}

	if (geometry->cylinders == 0)
		geometry->cylinders = 1;
#endif	/* ! STAGE1_5 */

  /* backup the geometry into array hd_geom or fd_geom. */

#if (! defined(GRUB_UTIL)) && (! defined(STAGE1_5))
    {
	unsigned long j;
	unsigned long d;

	/* check if the drive is virtual. */
	d = drive;
	j = DRIVE_MAP_SIZE;		/* real drive */
	if (! unset_int13_handler (1))
	    for (j = 0; j < DRIVE_MAP_SIZE; j++)
	    {
		if (drive != hooked_drive_map[j].from_drive)
			continue;
		if ((hooked_drive_map[j].max_sector & 0x3F) == 1 && hooked_drive_map[j].start_sector == 0 && hooked_drive_map[j].sector_count <= 1)
		{
			/* this is a map for the whole drive. */
			d = hooked_drive_map[j].to_drive;
			j = DRIVE_MAP_SIZE;	/* real drive */
		}
		break;
	    }

	if (j == DRIVE_MAP_SIZE)	/* real drive */
	{
	    if (d >= 0x80 && d < 0x84)
	    {
		d -= 0x80;
		if (hd_geom[d].sector_size != 512 || hd_geom[d].sectors <= 0 || hd_geom[d].sectors > 63 || hd_geom[d].heads > 256)
		{
			hd_geom[d].flags		= geometry->flags;
			hd_geom[d].sector_size		= geometry->sector_size;
			hd_geom[d].total_sectors	= geometry->total_sectors;
			hd_geom[d].heads		= geometry->heads;
			hd_geom[d].sectors		= geometry->sectors;
			hd_geom[d].cylinders		= geometry->cylinders;
		}
	    } else if (d < 4) {
		if (fd_geom[d].sector_size != 512 || fd_geom[d].sectors <= 0 || fd_geom[d].sectors > 63 || fd_geom[d].heads > 256)
		{
			fd_geom[d].flags		= geometry->flags;
			fd_geom[d].sector_size		= geometry->sector_size;
			fd_geom[d].total_sectors	= geometry->total_sectors;
			fd_geom[d].heads		= geometry->heads;
			fd_geom[d].sectors		= geometry->sectors;
			fd_geom[d].cylinders		= geometry->cylinders;
		}
	    }
	}
    }
#endif

  return 0;
}