stage2/disk_io.c

/* disk_io.c - implement abstract BIOS disk input and output */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1996  Erich Boleyn  <erich@uruk.org>
 *  Copyright (C) 1999, 2000  Free Software Foundation, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#include "shared.h"

#include "filesys.h"

#ifndef STAGE1_5
/* instrumentation variables */
void (*disk_read_hook) (int, int, int) = NULL;
void (*disk_read_func) (int, int, int) = NULL;

int print_possibilities;

static int do_completion;
static int unique;
static char *unique_string;

#endif

int fsmax;
struct fsys_entry fsys_table[NUM_FSYS + 1] =
{
  /* TFTP should come first because others don't handle net device.  */
# ifdef FSYS_TFTP
  {"tftp", tftp_mount, tftp_read, tftp_dir, tftp_close, 0},
# endif
# ifdef FSYS_FAT
  {"fat", fat_mount, fat_read, fat_dir, 0, 0},
# endif
# ifdef FSYS_EXT2FS
  {"ext2fs", ext2fs_mount, ext2fs_read, ext2fs_dir, 0, 0},
# endif
# ifdef FSYS_MINIX
  {"minix", minix_mount, minix_read, minix_dir, 0, 0},
# endif
# ifdef FSYS_REISERFS
  {"reiserfs", reiserfs_mount, reiserfs_read, reiserfs_dir, 0, reiserfs_embed},
# endif
  /* XX FFS should come last as it's superblock is commonly crossing tracks
     on floppies from track 1 to 2, while others only use 1.  */
# ifdef FSYS_FFS
  {"ffs", ffs_mount, ffs_read, ffs_dir, 0, ffs_embed},
# endif
  {0, 0, 0, 0, 0, 0}
};


/* These have the same format as "boot_drive" and "install_partition", but
   are meant to be working values. */
unsigned long current_drive = 0xFF;
unsigned long current_partition;

#ifndef STAGE1_5
/* The register ESI should contain the address of the partition to be
   used for loading a chain-loader when chain-loading the loader.  */
unsigned long boot_part_addr;
unsigned long boot_part_offset;
#endif

/*
 *  Global variables describing details of the filesystem
 */

/* FIXME: BSD evil hack */
#include "freebsd.h"
int bsd_evil_hack;

/* filesystem type */
int fsys_type = NUM_FSYS;
#ifndef NO_BLOCK_FILES
static int block_file = 0;
#endif /* NO_BLOCK_FILES */

/* these are the translated numbers for the open partition */
long part_start;
long part_length;

int current_slice;

/* disk buffer parameters */
int buf_drive = -1;
int buf_track;
struct geometry buf_geom;

/* filesystem common variables */
int filepos;
int filemax;


int
rawread (int drive, int sector, int byte_offset, int byte_len, char *buf)
{
  int slen = (byte_offset + byte_len + SECTOR_SIZE - 1) >> SECTOR_BITS;

  if (byte_len <= 0)
    return 1;

  while (byte_len > 0 && !errnum)
    {
      int soff, num_sect, bufaddr, track, size = byte_len;

      /*
       *  Check track buffer.  If it isn't valid or it is from the
       *  wrong disk, then reset the disk geometry.
       */
      if (buf_drive != drive)
	{
	  if (get_diskinfo (drive, &buf_geom))
	    {
	      errnum = ERR_NO_DISK;
	      return 0;
	    }
	  buf_drive = drive;
	  buf_track = -1;
	}

      /*  Get first sector of track  */
      soff = sector % buf_geom.sectors;
      track = sector - soff;
      num_sect = buf_geom.sectors - soff;
      bufaddr = BUFFERADDR + (soff * SECTOR_SIZE) + byte_offset;

      if (track != buf_track)
	{
	  int bios_err, read_start = track, read_len = buf_geom.sectors;

	  /*
	   *  If there's more than one read in this entire loop, then
	   *  only make the earlier reads for the portion needed.  This
	   *  saves filling the buffer with data that won't be used!
	   */
	  if (slen > num_sect)
	    {
	      read_start = sector;
	      read_len = num_sect;
	      bufaddr = BUFFERADDR + byte_offset;
	    }

	  bios_err = biosdisk (BIOSDISK_READ, drive, &buf_geom,
			       read_start, read_len, BUFFERSEG);
	  if (bios_err)
	    {
	      buf_track = -1;

	      if (bios_err == BIOSDISK_ERROR_GEOMETRY)
		errnum = ERR_GEOM;
	      else
		{
		  /*
		   *  If there was an error, try to load only the
		   *  required sector(s) rather than failing completely.
		   */
		  if (slen > num_sect
		      || biosdisk (BIOSDISK_READ, drive, &buf_geom,
				   sector, slen, BUFFERSEG))
		    errnum = ERR_READ;

		  bufaddr = BUFFERADDR + byte_offset;
		}
	    }
	  else
	    buf_track = track;
	}

      if (size > ((num_sect * SECTOR_SIZE) - byte_offset))
	size = (num_sect * SECTOR_SIZE) - byte_offset;

#ifndef STAGE1_5
      /*
       *  Instrumentation to tell which sectors were read and used.
       */
      if (disk_read_func)
	{
	  int sector_num = sector;
	  int length = SECTOR_SIZE - byte_offset;
	  if (length > size)
	    length = size;
	  (*disk_read_func) (sector_num++, byte_offset, length);
	  length = size - length;
	  if (length > 0)
	    {
	      while (length > SECTOR_SIZE)
		{
		  (*disk_read_func) (sector_num++, 0, SECTOR_SIZE);
		  length -= SECTOR_SIZE;
		}
	      (*disk_read_func) (sector_num, 0, length);
	    }
	}
#endif /* STAGE1_5 */
      memmove (buf, (char *) bufaddr, size);

      buf += size;
      byte_len -= size;
      sector += num_sect;
      slen -= num_sect;
      byte_offset = 0;
    }

  return (!errnum);
}


int
devread (int sector, int byte_offset, int byte_len, char *buf)
{
  /*
   *  Check partition boundaries
   */
  if (sector < 0
      || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS))
	  >= part_length))
    {
      errnum = ERR_OUTSIDE_PART;
      return 0;
    }

  /*
   *  Get the read to the beginning of a partition.
   */
  sector += byte_offset >> SECTOR_BITS;
  byte_offset &= SECTOR_SIZE - 1;

#if !defined(STAGE1_5)
  if (disk_read_hook && debug)
    printf ("<%d, %d, %d>", sector, byte_offset, byte_len);
#endif /* !STAGE1_5 */

  /*
   *  Call RAWREAD, which is very similar, but:
   *
   *    --  It takes an extra parameter, the drive number.
   *    --  It requires that "sector" is relative to the beginning
   *            of the disk.
   *    --  It doesn't handle offsets of more than 511 bytes into the
   *            sector.
   */
  return rawread (current_drive, part_start + sector, byte_offset,
		  byte_len, buf);
}

#ifndef STAGE1_5
static int
sane_partition (void)
{
  /* network drive */
  if (current_drive == NETWORK_DRIVE)
    return 1;
  
  if (!(current_partition & 0xFF000000uL)
      && (current_drive & 0xFFFFFF7F) < 8
      && (current_partition & 0xFF) == 0xFF
      && ((current_partition & 0xFF00) == 0xFF00
	  || (current_partition & 0xFF00) < 0x800)
      && ((current_partition >> 16) == 0xFF
	  || (current_drive & 0x80)))
    return 1;

  errnum = ERR_DEV_VALUES;
  return 0;
}
#endif /* ! STAGE1_5 */

static void
attempt_mount (void)
{
#ifndef STAGE1_5
  for (fsys_type = 0; fsys_type < NUM_FSYS
       && (*(fsys_table[fsys_type].mount_func)) () != 1; fsys_type++);

  if (fsys_type == NUM_FSYS && errnum == ERR_NONE)
    errnum = ERR_FSYS_MOUNT;
#else
  fsys_type = 0;
  if ((*(fsys_table[fsys_type].mount_func)) () != 1)
    {
      fsys_type = NUM_FSYS;
      errnum = ERR_FSYS_MOUNT;
    }
#endif
}


#ifndef STAGE1_5
/* Turn on the active flag for the partition SAVED_PARATITION in the
   drive SAVED_DRIVE. If an error occurs, return zero, otherwise return
   non-zero.  */
int
make_saved_active (void)
{
  if (saved_drive & 0x80)
    {
      /* Hard disk */
      int part = saved_partition >> 16;

      /* If the partition is not a primary partition, the active flag is
	 meaningless. (XXX: Really?)  */
      if (part > 3)
	{
	  errnum = ERR_DEV_VALUES;
	  return 0;
	}

      /* Read the MBR in the scratch space.  */
      if (! rawread (saved_drive, 0, 0, SECTOR_SIZE, (char *) SCRATCHADDR))
	return 0;

      /* If the partition is an extended partition, setting the active
	 flag violates the specification by IBM.  */
      if (IS_PC_SLICE_TYPE_EXTENDED (PC_SLICE_TYPE (SCRATCHADDR, part)))
	{
	  errnum = ERR_DEV_VALUES;
	  return 0;
	}

      /* Check if the active flag is disabled.  */
      if (PC_SLICE_FLAG (SCRATCHADDR, part) != PC_SLICE_FLAG_BOOTABLE)
	{
	  int i;

	  /* Clear all the active flags in this table.  */
	  for (i = 0; i < 4; i++)
	    PC_SLICE_FLAG (SCRATCHADDR, i) = 0;

	  /* Set the flag.  */
	  PC_SLICE_FLAG (SCRATCHADDR, part) = PC_SLICE_FLAG_BOOTABLE;

	  /* Clear the cache.  */
	  buf_track = -1;

	  /* Write back the MBR.  */
	  if (biosdisk (BIOSDISK_WRITE, saved_drive, &buf_geom,
			0, 1, SCRATCHSEG))
	    {
	      errnum = ERR_WRITE;
	      return 0;
	    }
	}
    }
  else
    {
      /* If the drive is not a hard disk drive, you shouldn't call this
	 function. (XXX: Should I just ignore this error?)  */
      errnum = ERR_DEV_VALUES;
      return 0;
    }

  return 1;
}

/* Hide/Unhide CURRENT_PARTITION.  */
int
set_partition_hidden_flag (int hidden)
{
  if (current_drive & 0x80)
    {
      int part = current_partition >> 16;

      if (part > 3)
	{
          errnum = ERR_NO_PART;
          return 0;
        }

      if (! rawread (current_drive, 0, 0, SECTOR_SIZE, (char *) SCRATCHADDR))
        return 0;

      if (hidden)
	PC_SLICE_TYPE (SCRATCHADDR, part) |= PC_SLICE_TYPE_HIDDEN_FLAG;
      else
	PC_SLICE_TYPE (SCRATCHADDR, part) &= ~PC_SLICE_TYPE_HIDDEN_FLAG;
      
      buf_track = -1;
      if (biosdisk (BIOSDISK_WRITE, current_drive, &buf_geom,
		    0, 1, SCRATCHSEG))
	{
	  errnum = ERR_WRITE;
	  return 0;
	}
    }

  return 1;
}


static void
check_and_print_mount (void)
{
  attempt_mount ();
  if (errnum == ERR_FSYS_MOUNT)
    errnum = ERR_NONE;
  if (!errnum)
    print_fsys_type ();
  print_error ();
}
#endif /* STAGE1_5 */


/* Get the information on next partition on the drive DRIVE.
   The caller must not modify the contents of the arguments when
   iterating this function. The partition representation in GRUB will
   be stored in *PARTITION. Likewise, the partition type in *TYPE, the
   start sector in *START, the length in *LEN, the offset of the
   partition table in *OFFSET, the entry number in the table in *ENTRY,
   the offset of the extended partition in *EXT_OFFSET.
   BUF is used to store a MBR, the boot sector of a partition, or
   a BSD label sector, and it must be at least 512 bytes length.
   When calling this function first, *PARTITION must be initialized to
   0xFFFFFF. The return value is zero if fails, otherwise non-zero.  */
int
next_partition (unsigned long drive, unsigned long dest,
		unsigned long *partition, int *type,
		unsigned long *start, unsigned long *len,
		unsigned long *offset, int *entry,
		unsigned long *ext_offset, char *buf)
{
  /* Forward declarations.  */
  auto int next_bsd_partition (void);
  auto int next_pc_slice (void);

  /* Get next BSD partition in current PC slice.  */
  int next_bsd_partition (void)
    {
      int i;
      int bsd_part_no = (*partition & 0xFF00) >> 8;

      /* If this is the first time...  */
      if (bsd_part_no == 0xFF)
	{
	  /* Check if the BSD label is within current PC slice.  */
	  if (*len < BSD_LABEL_SECTOR + 1)
	    {
	      errnum = ERR_BAD_PART_TABLE;
	      return 0;
	    }

	  /* Read the BSD label.  */
	  if (! rawread (drive, *start + BSD_LABEL_SECTOR,
			 0, SECTOR_SIZE, buf))
	    return 0;

	  /* Check if it is valid.  */
	  if (! BSD_LABEL_CHECK_MAG (buf))
	    {
	      errnum = ERR_BAD_PART_TABLE;
	      return 0;
	    }
	  
	  bsd_part_no = -1;
	}

      /* Search next valid BSD partition.  */
      for (i = bsd_part_no + 1; i < BSD_LABEL_NPARTS (buf); i++)
	{
	  if (BSD_PART_TYPE (buf, i))
	    {
	      /* Note that *TYPE and *PARTITION were set
		 for current PC slice.  */
	      *type = (BSD_PART_TYPE (buf, i) << 8) | (*type & 0xFF);
	      *start = BSD_PART_START (buf, i);
	      *len = BSD_PART_LENGTH (buf, i);
	      *partition = (*partition & 0xFF00FF) | (i << 8);

#ifndef STAGE1_5
	      /* XXX */
	      if ((drive & 0x80) && BSD_LABEL_DTYPE (buf) == DTYPE_SCSI)
		bsd_evil_hack = 4;
#endif /* ! STAGE1_5 */
	      
	      return 1;
	    }
	}

      errnum = ERR_NO_PART;
      return 0;
    }

  /* Get next PC slice. Be careful of that this function may return
     an empty PC slice (i.e. a partition whose type is zero) as well.  */
  int next_pc_slice (void)
    {
      int pc_slice_no = (*partition & 0xFF0000) >> 16;

      /* If this is the first time...  */
      if (pc_slice_no == 0xFF)
	{
	  *offset = 0;
	  *ext_offset = 0;
	  *entry = -1;
	  pc_slice_no = -1;
	}

      /* Read the MBR or the boot sector of the extended partition.  */
      if (! rawread (drive, *offset, 0, SECTOR_SIZE, buf))
	return 0;

      /* Check if it is valid.  */
      if (! PC_MBR_CHECK_SIG (buf))
	{
	  errnum = ERR_BAD_PART_TABLE;
	  return 0;
	}

      /* Increase the entry number.  */
      (*entry)++;

      /* If this is out of current partition table...  */
      if (*entry == PC_SLICE_MAX)
	{
	  int i;

	  /* Search the first extended partition in current table.  */
	  for (i = 0; i < PC_SLICE_MAX; i++)
	    {
	      if (IS_PC_SLICE_TYPE_EXTENDED (PC_SLICE_TYPE (buf, i)))
		{
		  /* Found. Set the new offset and the entry number,
		     and restart this function.  */
		  *offset = *ext_offset + PC_SLICE_START (buf, i);
		  if (! *ext_offset)
		    *ext_offset = *offset;
		  *entry = -1;
		  return next_pc_slice ();
		}
	    }

	  errnum = ERR_NO_PART;
	  return 0;
	}
      
      *type = PC_SLICE_TYPE (buf, *entry);
      *start = *offset + PC_SLICE_START (buf, *entry);
      *len = PC_SLICE_LENGTH (buf, *entry);

      /* The calculation of a PC slice number is complicated, because of
	 the rather odd definition of extended partitions. Even worse,
	 there is no guarantee that this is consistent with every
	 operating systems. Uggh.  */
      if (pc_slice_no < PC_SLICE_MAX
	  || (! IS_PC_SLICE_TYPE_EXTENDED (*type)
	      && *type != PC_SLICE_TYPE_NONE))
	pc_slice_no++;
      
      *partition = (pc_slice_no << 16) | 0xFFFF;
      return 1;
    }

  /* Start the body of this function.  */
  
#ifndef STAGE1_5
  if (current_drive == NETWORK_DRIVE)
    return 0;
#endif

  /* If previous partition is a BSD partition or a PC slice which
     contains BSD partitions...  */
  if ((*partition != 0xFFFFFF && IS_PC_SLICE_TYPE_BSD (*type))
      || ! (drive & 0x80))
    {
      if (*type == PC_SLICE_TYPE_NONE)
	*type = PC_SLICE_TYPE_FREEBSD;
      
      /* Get next BSD partition, if any.  */
      if (next_bsd_partition ())
	return 1;

      /* If the destination partition is a BSD partition and current
	 BSD partition has any error, abort the operation.  */
      if ((dest & 0xFF00) != 0xFF00
	  && ((dest & 0xFF0000) == 0xFF0000
	      || (dest & 0xFF0000) == (*partition & 0xFF0000)))
	return 0;

      /* Ignore the error.  */
      errnum = ERR_NONE;
    }
	  
  return next_pc_slice ();
}

#ifndef STAGE1_5
static unsigned long cur_part_offset;
static unsigned long cur_part_addr;
#endif

/* Open a partition.  */
int
real_open_partition (int flags)
{
  unsigned long dest_partition = current_partition;
  unsigned long part_offset;
  unsigned long ext_offset;
  int entry;
  char buf[SECTOR_SIZE];
  int bsd_part, pc_slice;

  /* For simplicity.  */
  auto int next (void);
  int next (void)
    {
      int ret = next_partition (current_drive, dest_partition,
				&current_partition, &current_slice,
				&part_start, &part_length,
				&part_offset, &entry, &ext_offset, buf);
      bsd_part = (current_partition >> 8) & 0xFF;
      pc_slice = current_partition >> 16;
      return ret;
    }
  
#ifndef STAGE1_5
  /* network drive */
  if (current_drive == NETWORK_DRIVE)
    return 1;
  
  if (! sane_partition ())
    return 0;
#endif

  bsd_evil_hack = 0;
  current_slice = 0;
  part_start = 0;

  /* Make sure that buf_geom is valid. */
  if (buf_drive != current_drive)
    {
      if (get_diskinfo (current_drive, &buf_geom))
	{
	  errnum = ERR_NO_DISK;
	  return 0;
	}
      buf_drive = current_drive;
      buf_track = -1;
    }
  part_length = buf_geom.total_sectors;

  /* If this is the whole disk, return here.  */
  if (! flags && current_partition == 0xFFFFFF)
    return 1;

  if (flags)
    dest_partition = 0xFFFFFF;

  /* Initialize CURRENT_PARTITION for next_partition.  */
  current_partition = 0xFFFFFF;
  
  while (next ())
    {
#ifndef STAGE1_5
    loop_start:
      
      cur_part_offset = part_offset;
      cur_part_addr = BOOT_PART_TABLE + (entry << 4);
#endif /* ! STAGE1_5 */

      /* If this is a valid partition...  */
      if (current_slice)
	{
#ifndef STAGE1_5
	  /* Display partition information.  */
	  if (flags && ! IS_PC_SLICE_TYPE_EXTENDED (current_slice))
	    {
	      if (! do_completion)
		{
		  if (current_drive & 0x80)
		    grub_printf ("   Partition num: %d, ",
				 current_partition >> 16);

		  if (! IS_PC_SLICE_TYPE_BSD (current_slice))
		    check_and_print_mount ();
		  else
		    {
		      int got_part = 0;
		      int saved_slice = current_slice;
		      
		      while (next ())
			{
			  if (bsd_part == 0xFF)
			    break;
			  
			  if (! got_part)
			    {
			      grub_printf ("[BSD sub-partitions immediately follow]\n");
			      got_part = 1;
			    }
			  
			  grub_printf ("     BSD Partition num: \'%c\', ",
				       bsd_part + 'a');
			  check_and_print_mount ();
			}

		      if (! got_part)
			grub_printf (" No BSD sub-partition found, partition type 0x%x\n",
				     saved_slice);
		      
		      if (errnum)
			{
			  errnum = ERR_NONE;
			  break;
			}
		      
		      goto loop_start;
		    }
		}
	      else
		{
		  if (bsd_part != 0xFF)
		    {
		      char str[16];
		      
		      if (! (current_drive & 0x80)
			  || (dest_partition >> 16) == pc_slice)
			grub_sprintf (str, "%c)", bsd_part + 'a');
		      else
			grub_sprintf (str, "%d,%c)",
				      pc_slice, bsd_part + 'a');
		      print_a_completion (str);
		    }
		  else if (! IS_PC_SLICE_TYPE_BSD (current_slice))
		    {
		      char str[8];
		      
		      grub_sprintf (str, "%d)", pc_slice);
		      print_a_completion (str);
		    }
		}
	    }
	  
	  errnum = ERR_NONE;
#endif /* ! STAGE1_5 */
	  
	  /* Check if this is the destination partition.  */
	  if (! flags
	      && (dest_partition == current_partition
		  || ((dest_partition >> 16) == 0xFF
		      && ((dest_partition >> 8) & 0xFF) == bsd_part)))
	    return 1;
	}
    }

#ifndef STAGE1_5
  if (flags)
    {
      if (! (current_drive & 0x80))
	{
	  current_partition = 0xFFFFFF;
	  check_and_print_mount ();
	}
      
      errnum = ERR_NONE;
      return 1;
    }
#endif /* ! STAGE1_5 */
  
  return 0;
}


int
open_partition (void)
{
  return real_open_partition (0);
}


#ifndef STAGE1_5
/* XX used for device completion in 'set_device' and 'print_completions' */
static int incomplete, disk_choice;
static enum
{
  PART_UNSPECIFIED = 0,
  PART_DISK,
  PART_CHOSEN,
}
part_choice;
#endif /* ! STAGE1_5 */

char *
set_device (char *device)
{
#ifdef STAGE1_5
    /* In Stage 1.5, the first 4 bytes of FILENAME has a device number.  */
  unsigned long dev = *((unsigned long *) device);
  int drive = (dev >> 24) & 0xFF;
  int partition = dev & 0xFFFFFF;

  /* If DRIVE is disabled (0xFF), use SAVED_DRIVE instead.  */
  if (drive == 0xFF)
    current_drive = saved_drive;
  else
    current_drive = drive;

  /* The `partition' part must always have a valid number.  */
  current_partition = partition;
  
  return device + sizeof (unsigned long);
  
#else /* ! STAGE1_5 */
  
  int result = 0;

  incomplete = 0;
  disk_choice = 1;
  part_choice = PART_UNSPECIFIED;
  current_drive = saved_drive;
  current_partition = 0xFFFFFF;

  if (*device == '(' && !*(device + 1))
    /* user has given '(' only, let disk_choice handle what disks we have */
    return device + 1;

  if (*device == '(' && *(++device))
    {
      if (*device != ',' && *device != ')')
	{
	  char ch = *device;

	  if (*device == 'f' || *device == 'h')
	    {
	      /* user has given '([fh]', check for resp. add 'd' and
		 let disk_choice handle what disks we have */
	      if (!*(device + 1))
		{
		  device++;
		  *device++ = 'd';
		  *device = '\0';
		  return device;
		}
	      else if (*(device + 1) == 'd' && !*(device + 2))
		return device + 2;
	    }

	  if ((*device == 'f' || *device == 'h' || *device == 'n')
	      && (device += 2, (*(device - 1) != 'd')))
	    errnum = ERR_NUMBER_PARSING;

	  if (ch == 'n')
	    current_drive = NETWORK_DRIVE;
	  else
	    {
	      safe_parse_maxint (&device, (int *) &current_drive);
	      
	      disk_choice = 0;
	      if (ch == 'h')
		current_drive += 0x80;
	    }
	}

      if (errnum)
	return 0;

      if (*device == ')')
	{
	  part_choice = PART_CHOSEN;
	  result = 1;
	}
      else if (*device == ',')
	{
	  /* Either an absolute PC or BSD partition. */
	  disk_choice = 0;
	  part_choice ++;
	  device++;

	  if (*device >= '0' && *device <= '9')
	    {
	      part_choice ++;
	      current_partition = 0;

	      if (!(current_drive & 0x80)
		  || !safe_parse_maxint (&device, (int *) &current_partition)
		  || current_partition > 254)
		{
		  errnum = ERR_DEV_FORMAT;
		  return 0;
		}

	      current_partition = (current_partition << 16) + 0xFFFF;

	      if (*device == ',')
		device++;
	      
	      if (*device >= 'a' && *device <= 'h')
		{
		  current_partition = (((*(device++) - 'a') << 8)
				       | (current_partition & 0xFF00FF));
		}
	    }
	  else if (*device >= 'a' && *device <= 'h')
	    {
	      part_choice ++;
	      current_partition = ((*(device++) - 'a') << 8) | 0xFF00FF;
	    }

	  if (*device == ')')
	    {
	      if (part_choice == PART_DISK)
		{
		  current_partition = saved_partition;
		  part_choice ++;
		}

	      result = 1;
	    }
	}
    }

  if (! sane_partition ())
    return 0;
  
  if (result)
    return device + 1;
  else
    {
      if (!*device)
	incomplete = 1;
      errnum = ERR_DEV_FORMAT;
    }

  return 0;
  
#endif /* ! STAGE1_5 */
}

/*
 *  This performs a "mount" on the current device, both drive and partition
 *  number.
 */

int
open_device (void)
{
  if (open_partition ())
    attempt_mount ();

  if (errnum != ERR_NONE)
    return 0;

  return 1;
}


#ifndef STAGE1_5
int
set_bootdev (int hdbias)
{
  int i, j;

  /* Save the boot partition for chain-loading.  */
  boot_part_offset = cur_part_offset;
  boot_part_addr = cur_part_addr;
  
  /*
   *  Set BSD boot device.
   */
  i = (saved_partition >> 16) + 2;
  if (saved_partition == 0xFFFFFF)
    i = 1;
  else if ((saved_partition >> 16) == 0xFF)
    i = 0;

  /* FIXME: extremely evil hack!!! */
  j = 2;
  if (saved_drive & 0x80)
    j = bsd_evil_hack;

  return MAKEBOOTDEV (j, (i >> 4), (i & 0xF),
		      ((saved_drive - hdbias) & 0x7F),
		      ((saved_partition >> 8) & 0xFF));
}
#endif /* STAGE1_5 */


static char *
setup_part (char *filename)
{
#ifdef STAGE1_5

  if (! (filename = set_device (filename)))
    {
      current_drive = 0xFF;
      return 0;
    }
  
# ifndef NO_BLOCK_FILES
  if (*filename != '/')
    open_partition ();
  else
# endif /* ! NO_BLOCK_FILES */
    open_device ();
  
#else /* ! STAGE1_5 */
  
  if (*filename == '(')
    {
      if ((filename = set_device (filename)) == 0)
	{
	  current_drive = 0xFF;
	  return 0;
	}
# ifndef NO_BLOCK_FILES
      if (*filename != '/')
	open_partition ();
      else
# endif /* ! NO_BLOCK_FILES */
	open_device ();
    }
  else if (saved_drive != current_drive
	   || saved_partition != current_partition
	   || (*filename == '/' && fsys_type == NUM_FSYS)
	   || buf_drive == -1)
    {
      current_drive = saved_drive;
      current_partition = saved_partition;
      /* allow for the error case of "no filesystem" after the partition
         is found.  This makes block files work fine on no filesystem */
# ifndef NO_BLOCK_FILES
      if (*filename != '/')
	open_partition ();
      else
# endif /* ! NO_BLOCK_FILES */
	open_device ();
    }
  
#endif /* ! STAGE1_5 */
  
  if (errnum && (*filename == '/' || errnum != ERR_FSYS_MOUNT))
    return 0;
  else
    errnum = 0;

#ifndef STAGE1_5
  if (!sane_partition ())
    return 0;
#endif

  return filename;
}


#ifndef STAGE1_5
/*
 *  This prints the filesystem type or gives relevant information.
 */

void
print_fsys_type (void)
{
  if (! do_completion)
    {
      printf (" Filesystem type ");
      
      if (fsys_type != NUM_FSYS)
	printf ("is %s, ", fsys_table[fsys_type].name);
      else
	printf ("unknown, ");
      
      if (current_partition == 0xFFFFFF)
	printf ("using whole disk\n");
      else
	printf ("partition type 0x%x\n", current_slice & 0xFF);
    }
}
#endif /* STAGE1_5 */

#ifndef STAGE1_5
/* If DO_COMPLETION is true, just print NAME. Otherwise save the unique
   part into UNIQUE_STRING.  */
void
print_a_completion (char *name)
{
  /* If NAME is "." or "..", do not count it.  */
  if (grub_strcmp (name, ".") == 0 || grub_strcmp (name, "..") == 0)
    return;
  
  if (do_completion)
    {
      char *buf = unique_string;
      
      if (! unique)
	while ((*buf++ = *name++))
	  ;
      else
	{
	  while (*buf && (*buf == *name))
	    {
	      buf++;
	      name++;
	    }
	  /* mismatch, strip it.  */
	  *buf = '\0';
	}
    }
  else
    grub_printf (" %s", name);
  
  unique++;
}

/*
 *  This lists the possible completions of a device string, filename, or
 *  any sane combination of the two.
 */

int
print_completions (int is_filename, int is_completion)
{
  char *buf = (char *) COMPLETION_BUF;
  char *ptr = buf;

  unique_string = (char *) UNIQUE_BUF;
  *unique_string = 0;
  unique = 0;
  do_completion = is_completion;

  if (! is_filename)
    {
      /* Print the completions of builtin commands.  */
      struct builtin **builtin;

      if (! is_completion)
	grub_printf (" Possible commands are:");
      
      for (builtin = builtin_table; (*builtin); builtin++)
	{
	  /* If *BUILTIN cannot be run in the command-line, skip it.  */
	  if (! ((*builtin)->flags & BUILTIN_CMDLINE))
	    continue;

	  if (substring (buf, (*builtin)->name) <= 0)
	    print_a_completion ((*builtin)->name);
	}

      if (is_completion && *unique_string)
	{
	  if (unique == 1)
	    {
	      char *u = unique_string + grub_strlen (unique_string);

	      *u++ = ' ';
	      *u = 0;
	    }
	  
	  grub_strcpy (buf, unique_string);
	}

      if (! is_completion)
	grub_putchar ('\n');
      
      print_error ();
      do_completion = 0;
      if (errnum)
	return -1;
      else
	return unique - 1;
    }

  if (*buf == '/' || (ptr = set_device (buf)) || incomplete)
    {
      errnum = 0;

      if (*buf == '(' && (incomplete || ! *ptr))
	{
	  if (! part_choice)
	    {
	      /* disk completions */
	      int disk_no, i, j;
	      struct geometry geom;

	      if (! is_completion)
		grub_printf (" Possible disks are: ");

	      for (i = (ptr && (*(ptr-2) == 'h' && *(ptr-1) == 'd') ? 1 : 0);
		   i < (ptr && (*(ptr-2) == 'f' && *(ptr-1) == 'd') ? 1 : 2);
		   i++)
		{
		  for (j = 0; j < 8; j++)
		    {
		      disk_no = (i * 0x80) + j;
		      if ((disk_choice || disk_no == current_drive)
			  && ! get_diskinfo (disk_no, &geom))
			{
			  char dev_name[8];

			  grub_sprintf (dev_name, "%cd%d", i ? 'h' : 'f', j);
			  print_a_completion (dev_name);
			}
		    }
		}

	      if (is_completion && *unique_string)
		{
		  ptr = buf;
		  while (*ptr != '(')
		    ptr--;
		  ptr++;
		  grub_strcpy (ptr, unique_string);
		  if (unique == 1)
		    {
		      ptr += grub_strlen (ptr);
		      if (*unique_string == 'h')
			{
			  *ptr++ = ',';
			  *ptr = 0;
			}
		      else
			{
			  *ptr++ = ')';
			  *ptr = 0;
			}
		    }
		}

	      if (! is_completion)
		grub_putchar ('\n');
	    }
	  else
	    {
	      /* partition completions */
	      if (part_choice == PART_CHOSEN
		  && open_partition ()
		  && ! IS_PC_SLICE_TYPE_BSD (current_slice))
		{
		  unique = 1;
		  ptr = buf + grub_strlen (buf);
		  if (*(ptr - 1) != ')')
		    {
		      *ptr++ = ')';
		      *ptr = 0;
		    }
		}
	      else
		{
		  if (! is_completion)
		    grub_printf (" Possible partitions are:\n");
		  real_open_partition (1);
		  
		  if (is_completion && *unique_string)
		    {
		      ptr = buf;
		      while (*ptr++ != ',')
			;
		      grub_strcpy (ptr, unique_string);
		    }
		}
	    }
	}
      else if (ptr && *ptr == '/')
	{
	  /* filename completions */
	  if (! is_completion)
	    grub_printf (" Possible files are:");
	  
	  dir (buf);
	  
	  if (is_completion && *unique_string)
	    {
	      ptr += grub_strlen (ptr);
	      while (*ptr != '/')
		ptr--;
	      ptr++;
	      
	      grub_strcpy (ptr, unique_string);
	      
	      if (unique == 1)
		{
		  ptr += grub_strlen (unique_string);

		  /* Check if the file UNIQUE_STRING is a directory.  */
		  *ptr = '/';
		  *(ptr + 1) = 0;
		  
		  dir (buf);
		  
		  /* Restore the original unique value.  */
		  unique = 1;
		  
		  if (errnum)
		    {
		      /* Regular file */
		      errnum = 0;
		      *ptr = ' ';
		      *(ptr + 1) = 0;
		    }
		}
	    }
	  
	  if (! is_completion)
	    grub_putchar ('\n');
	}
      else
	errnum = ERR_BAD_FILENAME;
    }

  print_error ();
  do_completion = 0;
  if (errnum)
    return -1;
  else
    return unique - 1;
}
#endif /* STAGE1_5 */


/*
 *  This is the generic file open function.
 */

int
grub_open (char *filename)
{
#ifndef NO_DECOMPRESSION
  compressed_file = 0;
#endif /* NO_DECOMPRESSION */

  /* if any "dir" function uses/sets filepos, it must
     set it to zero before returning if opening a file! */
  filepos = 0;

  if (!(filename = setup_part (filename)))
    return 0;

#ifndef NO_BLOCK_FILES
  block_file = 0;
#endif /* NO_BLOCK_FILES */

  /* This accounts for partial filesystem implementations. */
  fsmax = MAXINT;

  if (*filename != '/')
    {
#ifndef NO_BLOCK_FILES
      char *ptr = filename;
      int tmp, list_addr = BLK_BLKLIST_START;
      filemax = 0;

      while (list_addr < BLK_MAX_ADDR)
	{
	  tmp = 0;
	  safe_parse_maxint (&ptr, &tmp);
	  errnum = 0;

	  if (*ptr != '+')
	    {
	      if ((*ptr && *ptr != '/' && !isspace (*ptr))
		  || tmp == 0 || tmp > filemax)
		errnum = ERR_BAD_FILENAME;
	      else
		filemax = tmp;

	      break;
	    }

	  /* since we use the same filesystem buffer, mark it to
	     be remounted */
	  fsys_type = NUM_FSYS;

	  BLK_BLKSTART (list_addr) = tmp;
	  ptr++;

	  if (!safe_parse_maxint (&ptr, &tmp)
	      || tmp == 0
	      || (*ptr && *ptr != ',' && *ptr != '/' && !isspace (*ptr)))
	    {
	      errnum = ERR_BAD_FILENAME;
	      break;
	    }

	  BLK_BLKLENGTH (list_addr) = tmp;

	  filemax += (tmp * SECTOR_SIZE);
	  list_addr += BLK_BLKLIST_INC_VAL;

	  if (*ptr != ',')
	    break;

	  ptr++;
	}

      if (list_addr < BLK_MAX_ADDR && ptr != filename && !errnum)
	{
	  block_file = 1;
	  BLK_CUR_FILEPOS = 0;
	  BLK_CUR_BLKLIST = BLK_BLKLIST_START;
	  BLK_CUR_BLKNUM = 0;

#ifndef NO_DECOMPRESSION
	  return gunzip_test_header ();
#else /* NO_DECOMPRESSION */
	  return 1;
#endif /* NO_DECOMPRESSION */
	}
#else /* NO_BLOCK_FILES */
      errnum = ERR_BAD_FILENAME;
#endif /* NO_BLOCK_FILES */
    }

  if (!errnum && fsys_type == NUM_FSYS)
    errnum = ERR_FSYS_MOUNT;

# ifndef STAGE1_5
  /* set "dir" function to open a file */
  print_possibilities = 0;
# endif

  if (!errnum && (*(fsys_table[fsys_type].dir_func)) (filename))
    {
#ifndef NO_DECOMPRESSION
      return gunzip_test_header ();
#else /* NO_DECOMPRESSION */
      return 1;
#endif /* NO_DECOMPRESSION */
    }

  return 0;
}


int
grub_read (char *buf, int len)
{
  /* Make sure "filepos" is a sane value */
  if ((filepos < 0) || (filepos > filemax))
    filepos = filemax;

  /* Make sure "len" is a sane value */
  if ((len < 0) || (len > (filemax - filepos)))
    len = filemax - filepos;

  /* if target file position is past the end of
     the supported/configured filesize, then
     there is an error */
  if (filepos + len > fsmax)
    {
      errnum = ERR_FILELENGTH;
      return 0;
    }

#ifndef NO_DECOMPRESSION
  if (compressed_file)
    return gunzip_read (buf, len);
#endif /* NO_DECOMPRESSION */

#ifndef NO_BLOCK_FILES
  if (block_file)
    {
      int size, off, ret = 0;

      while (len && !errnum)
	{
	  /* we may need to look for the right block in the list(s) */
	  if (filepos < BLK_CUR_FILEPOS)
	    {
	      BLK_CUR_FILEPOS = 0;
	      BLK_CUR_BLKLIST = BLK_BLKLIST_START;
	      BLK_CUR_BLKNUM = 0;
	    }

	  /* run BLK_CUR_FILEPOS up to filepos */
	  while (filepos > BLK_CUR_FILEPOS)
	    {
	      if ((filepos - (BLK_CUR_FILEPOS & ~(SECTOR_SIZE - 1)))
		  >= SECTOR_SIZE)
		{
		  BLK_CUR_FILEPOS += SECTOR_SIZE;
		  BLK_CUR_BLKNUM++;

		  if (BLK_CUR_BLKNUM >= BLK_BLKLENGTH (BLK_CUR_BLKLIST))
		    {
		      BLK_CUR_BLKLIST += BLK_BLKLIST_INC_VAL;
		      BLK_CUR_BLKNUM = 0;
		    }
		}
	      else
		BLK_CUR_FILEPOS = filepos;
	    }

	  off = filepos & (SECTOR_SIZE - 1);
	  size = ((BLK_BLKLENGTH (BLK_CUR_BLKLIST) - BLK_CUR_BLKNUM)
		  * SECTOR_SIZE) - off;
	  if (size > len)
	    size = len;

#ifndef STAGE1_5
	  disk_read_func = disk_read_hook;
#endif /* STAGE1_5 */

	  /* read current block and put it in the right place in memory */
	  devread (BLK_BLKSTART (BLK_CUR_BLKLIST) + BLK_CUR_BLKNUM,
		   off, size, buf);

#ifndef STAGE1_5
	  disk_read_func = NULL;
#endif /* STAGE1_5 */

	  len -= size;
	  filepos += size;
	  ret += size;
	  buf += size;
	}

      if (errnum)
	ret = 0;

      return ret;
    }
#endif /* NO_BLOCK_FILES */

  if (fsys_type == NUM_FSYS)
    {
      errnum = ERR_FSYS_MOUNT;
      return 0;
    }

  return (*(fsys_table[fsys_type].read_func)) (buf, len);
}

#ifndef STAGE1_5
/* Reposition a file offset.  */
int
grub_seek (int offset)
{
  if (offset > filemax || offset < 0)
    return -1;

  filepos = offset;
  return offset;
}

int
dir (char *dirname)
{
#ifndef NO_DECOMPRESSION
  compressed_file = 0;
#endif /* NO_DECOMPRESSION */

  if (!(dirname = setup_part (dirname)))
    return 0;

  if (*dirname != '/')
    errnum = ERR_BAD_FILENAME;

  if (fsys_type == NUM_FSYS)
    errnum = ERR_FSYS_MOUNT;

  if (errnum)
    return 0;

  /* set "dir" function to list completions */
  print_possibilities = 1;

  return (*(fsys_table[fsys_type].dir_func)) (dirname);
}
#endif /* STAGE1_5 */

void 
grub_close (void)
{
#ifndef NO_BLOCK_FILES
  if (block_file)
    return;
#endif /* NO_BLOCK_FILES */
  
  if (fsys_table[fsys_type].close_func != 0)
    (*(fsys_table[fsys_type].close_func)) ();
}