mkdosfs.c.bak

linux下格式化U盘的函数,从mkdosfs而来

	return(_ERROR_);
  if(mark_FAT_cluster (cluster, value)==_ERROR_)	return _ERROR_;
}


/* Perform a test on a block.  Return the number of blocks that could be read successfully */

static long
do_check (char *buffer, int try, off_t current_block)
{
  long got;

  if (llseek (dev, current_block * BLOCK_SIZE, SEEK_SET) /* Seek to the correct location */
      != current_block * BLOCK_SIZE)
    //die ("seek failed during testing for blocks");
	return(_ERROR_);
  got = read (dev, buffer, try * BLOCK_SIZE);	/* Try reading! */
  if (got < 0)
    got = 0;

  if (got & (BLOCK_SIZE - 1))
    printf ("Unexpected values in do_check: probably bugs\n");
  got /= BLOCK_SIZE ;

  return got;
}


/* Alarm clock handler - display the status of the quest for bad blocks!  Then retrigger the alarm for five senconds
   later (so we can come here again) */

static void
alarm_intr (int alnum)
{
  if (currently_testing >= blocks)
    return;

  signal (SIGALRM, alarm_intr);
  alarm (5);
  if (!currently_testing)
    return;

  printf ("%lld... ", (unsigned long long)currently_testing);
  fflush (stdout);
}


static int
check_blocks (void)
{
  int try, got;
  int i;
  static char blkbuf[BLOCK_SIZE * TEST_BUFFER_BLOCKS];

  if (verbose)
    {
      printf ("Searching for bad blocks ");
      fflush (stdout);
    }
  currently_testing = 0;
  if (verbose)
    {
      signal (SIGALRM, alarm_intr);
      alarm (5);
    }
  try = TEST_BUFFER_BLOCKS;
  while (currently_testing < blocks)
    {
      if (currently_testing + try > blocks)
	try = blocks - currently_testing;
      got = do_check (blkbuf, try, currently_testing);
		if(got==_ERROR_)	return -1;
      currently_testing += got;
      if (got == try)
	{
	  try = TEST_BUFFER_BLOCKS;
	  continue;
	}
      else
	try = 1;
      if (currently_testing < start_data_block)
	//die ("bad blocks before data-area: cannot make fs");
			return(_ERROR_);
      for (i = 0; i < SECTORS_PER_BLOCK; i++)	/* Mark all of the sectors in the block as bad */
		{
			if(mark_sector_bad (currently_testing * SECTORS_PER_BLOCK + i)==_ERROR_)
				return _ERROR_;
		}
      badblocks++;
      currently_testing++;
    }

  if (verbose)
    printf ("\n");

  if (badblocks)
    printf ("%d bad block%s\n", badblocks,
	    (badblocks > 1) ? "s" : "");
	return(_OK_);
}


static int
get_list_blocks (char *filename)
{
  int i;
  FILE *listfile;
  unsigned long blockno;

  listfile = fopen (filename, "r");
  if (listfile == (FILE *) NULL)
    //die ("Can't open file of bad blocks");
		return (_ERROR_);
  while (!feof (listfile))
    {
      fscanf (listfile, "%ld\n", &blockno);
      for (i = 0; i < SECTORS_PER_BLOCK; i++)	/* Mark all of the sectors in the block as bad */
		{
			if(mark_sector_bad (blockno * SECTORS_PER_BLOCK + i)==_ERROR_)
				return _ERROR_;
		}
      badblocks++;
    }
  fclose (listfile);

  if (badblocks)
    printf ("%d bad block%s\n", badblocks,
	    (badblocks > 1) ? "s" : "");
	return (_OK_);
}


/* Given a file descriptor and an offset, check whether the offset is a valid offset for the file - return FALSE if it
   isn't valid or TRUE if it is */

static int
valid_offset (int fd, loff_t offset)
{
  char ch;

  if (llseek (fd, offset, SEEK_SET) < 0)
    return FALSE;
  if (read (fd, &ch, 1) < 1)
    return FALSE;
  return TRUE;
}


/* Given a filename, look to see how many blocks of BLOCK_SIZE are present, returning the answer */

static unsigned long long
count_blocks (char *filename)
{
  off_t high, low;
  int fd;

  if ((fd = open (filename, O_RDONLY)) < 0)
    {
      perror (filename);
      //exit (1);
		return(_ERROR_);
    }

  /* first try SEEK_END, which should work on most devices nowadays */
  if ((low = llseek(fd, 0, SEEK_END)) <= 0) {
      low = 0;
      for (high = 1; valid_offset (fd, high); high *= 2)
	  low = high;
      while (low < high - 1) {
	  const loff_t mid = (low + high) / 2;
	  if (valid_offset (fd, mid))
	      low = mid;
	  else
	      high = mid;
      }
      ++low;
  }

  close (fd);
  return low / BLOCK_SIZE;
}


/* Check to see if the specified device is currently mounted - abort if it is */

static int
check_mount (char *device_name)
{
  FILE *f;
  struct mntent *mnt;

  if ((f = setmntent (MOUNTED, "r")) == NULL)
    return;
  while ((mnt = getmntent (f)) != NULL)
    if (strcmp (device_name, mnt->mnt_fsname) == 0)
      //die ("%s contains a mounted file system.");
		return(_ERROR_);
  endmntent (f);
	return(_OK_);
}


/* Establish the geometry and media parameters for the device */

static int
establish_params (int device_num,int size)
{
  long loop_size;
  struct hd_geometry geometry;
  struct floppy_struct param;

  if ((0 == device_num) || ((device_num & 0xff00) == 0x0200))
    /* file image or floppy disk */
    {
      if (0 == device_num)
	{
	  param.size = size/512;
	  switch(param.size)
	    {
	    case 720:
	      param.sect = 9 ;
	      param.head = 2;
	      break; 
	    case 1440:
	      param.sect = 9;
	      param.head = 2;
	      break;
	    case 2400:
	      param.sect = 15;
	      param.head = 2;
	      break;
	    case 2880:
	      param.sect = 18;
	      param.head = 2;
	      break;
	    case 5760:
	      param.sect = 36;
	      param.head = 2;
	      break;
	    default:
	      /* fake values */
	      param.sect = 32;
	      param.head = 64;
	      break;
	    }
	  
	}
      else 	/* is a floppy diskette */
	{
	  if (ioctl (dev, FDGETPRM, &param))	/*  Can we get the diskette geometry? */
	    //die ("unable to get diskette geometry for '%s'");
			return(_ERROR_);
	}
      bs.secs_track = CT_LE_W(param.sect);	/*  Set up the geometry information */
      bs.heads = CT_LE_W(param.head);
      switch (param.size)	/*  Set up the media descriptor byte */
	{
	case 720:		/* 5.25", 2, 9, 40 - 360K */
	  bs.media = (char) 0xfd;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 112;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 1440:		/* 3.5", 2, 9, 80 - 720K */
	  bs.media = (char) 0xf9;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 112;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 2400:		/* 5.25", 2, 15, 80 - 1200K */
	  bs.media = (char) 0xf9;
	  bs.cluster_size = (char)(atari_format ? 2 : 1);
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;
	  
	case 5760:		/* 3.5", 2, 36, 80 - 2880K */
	  bs.media = (char) 0xf0;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 2880:		/* 3.5", 2, 18, 80 - 1440K */
	floppy_default:
	  bs.media = (char) 0xf0;
	  bs.cluster_size = (char)(atari_format ? 2 : 1);
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;

	default:		/* Anything else */
	  if (0 == device_num)
	      goto def_hd_params;
	  else
	      goto floppy_default;
	}
    }
  else if ((device_num & 0xff00) == 0x0700) /* This is a loop device */
    {
      if (ioctl (dev, BLKGETSIZE, &loop_size)) 
			return(_ERROR_);	
	//die ("unable to get loop device size");

      switch (loop_size)  /* Assuming the loop device -> floppy later */
	{
	case 720:		/* 5.25", 2, 9, 40 - 360K */
	  bs.secs_track = CF_LE_W(9);
	  bs.heads = CF_LE_W(2);
	  bs.media = (char) 0xfd;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 112;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 1440:		/* 3.5", 2, 9, 80 - 720K */
	  bs.secs_track = CF_LE_W(9);
	  bs.heads = CF_LE_W(2);
	  bs.media = (char) 0xf9;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 112;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 2400:		/* 5.25", 2, 15, 80 - 1200K */
	  bs.secs_track = CF_LE_W(15);
	  bs.heads = CF_LE_W(2);
	  bs.media = (char) 0xf9;
	  bs.cluster_size = (char)(atari_format ? 2 : 1);
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;
	  
	case 5760:		/* 3.5", 2, 36, 80 - 2880K */
	  bs.secs_track = CF_LE_W(36);
	  bs.heads = CF_LE_W(2);
	  bs.media = (char) 0xf0;
	  bs.cluster_size = (char) 2;
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;

	case 2880:		/* 3.5", 2, 18, 80 - 1440K */
	  bs.secs_track = CF_LE_W(18);
	  bs.heads = CF_LE_W(2);
	  bs.media = (char) 0xf0;
	  bs.cluster_size = (char)(atari_format ? 2 : 1);
	  bs.dir_entries[0] = (char) 224;
	  bs.dir_entries[1] = (char) 0;
	  break;

	default:		/* Anything else: default hd setup */
	  printf("Loop device does not match a floppy size, using "
		 "default hd params\n");
	  bs.secs_track = CT_LE_W(32); /* these are fake values... */
	  bs.heads = CT_LE_W(64);
	  goto def_hd_params;
	}
    }
  else
    /* Must be a hard disk then! */
    {
      /* Can we get the drive geometry? (Note I'm not too sure about */
      /* whether to use HDIO_GETGEO or HDIO_REQ) */
      if (ioctl (dev, HDIO_GETGEO, &geometry)) {
	printf ("unable to get drive geometry, using default 255/63");
        bs.secs_track = CT_LE_W(63);
        bs.heads = CT_LE_W(255);
      }
      else {
        bs.secs_track = CT_LE_W(geometry.sectors);	/* Set up the geometry information */
        bs.heads = CT_LE_W(geometry.heads);
      }
    def_hd_params:
      bs.media = (char) 0xf8; /* Set up the media descriptor for a hard drive */
      bs.dir_entries[0] = (char) 0;	/* Default to 512 entries */
      bs.dir_entries[1] = (char) 2;
      if (!size_fat && blocks*SECTORS_PER_BLOCK > 1064960) {
	  if (verbose) printf("Auto-selecting FAT32 for large filesystem\n");
	  size_fat = 32;
      }
      if (size_fat == 32) {
	  /* For FAT32, try to do the same as M$'s format command:
	   * fs size < 256M: 0.5k clusters
	   * fs size <   8G: 4k clusters
	   * fs size <  16G: 8k clusters
	   * fs size >= 16G: 16k clusters
	   */
	  unsigned long sz_mb =
	      (blocks+(1<<(20-BLOCK_SIZE_BITS))-1) >> (20-BLOCK_SIZE_BITS);
	  bs.cluster_size = sz_mb >= 16*1024 ? 32 :
			    sz_mb >=  8*1024 ? 16 :
			    sz_mb >=     256 ?  8 :
					        1;
      }
      else {
	  /* FAT12 and FAT16: start at 4 sectors per cluster */
	  bs.cluster_size = (char) 4;
      }
    }
	return(_OK_);
}


/* Create the filesystem data tables */