fs/ext2/dev.c

/*
 * (C) Copyright 2004
 *  esd gmbh <www.esd-electronics.com>
 *  Reinhard Arlt <reinhard.arlt@esd-electronics.com>
 *
 *  based on code of fs/reiserfs/dev.c by
 *
 *  (C) Copyright 2003 - 2004
 *  Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
 *
 *  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 <common.h>
#if (CONFIG_COMMANDS & CFG_CMD_EXT2)

#include <config.h>
#include <ext2fs.h>

static block_dev_desc_t *ext2fs_block_dev_desc;
static disk_partition_t part_info;

#undef DEBUG
int ext2fs_set_blk_dev
    (
    block_dev_desc_t *rbdd, 
    int               part
    )
    {
    ext2fs_block_dev_desc = rbdd;

    if (part == 0) 
        {
	/* disk doesn't use partition table */
	part_info.start = 0;
	part_info.size = rbdd->lba;
	part_info.blksz = rbdd->blksz;
	} 
    else 
        {
	if (get_partition_info (ext2fs_block_dev_desc, part, &part_info)) 
	    {
	    return 0;
	    }
	}
    return (part_info.size);
    }


int ext2fs_devread 
    (
    int   sector, 
    int   byte_offset, 
    int   byte_len, 
    char *buf
    )
    {
    char sec_buf[SECTOR_SIZE];
    unsigned block_len;
/*
 *  Check partition boundaries
 */
    if ((sector < 0) || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >= part_info.size)) 
        {
/*      errnum = ERR_OUTSIDE_PART; */
	printf (" ** ext2fs_devread() read outside partition sector %d\n", sector);
	return(0);
	}

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

#if defined(DEBUG)
    printf (" <%d, %d, %d>\n", sector, byte_offset, byte_len);
#endif

    if (ext2fs_block_dev_desc == NULL)
        {
        printf("** Invalid Block Device Descriptor (NULL)\n");
	return(0);
	}

    if (byte_offset != 0) 
        {
/*      read first part which isn't aligned with start of sector */
	if (ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev, part_info.start+sector, 1, (unsigned long *)sec_buf) != 1) 
	    {
	    printf (" ** ext2fs_devread() read error **\n");
	    return(0);
	    }
	memcpy(buf, sec_buf+byte_offset, min(SECTOR_SIZE-byte_offset, byte_len));
	buf+=min(SECTOR_SIZE-byte_offset, byte_len);
	byte_len-=min(SECTOR_SIZE-byte_offset, byte_len);
	sector++;
	}

/*  read sector aligned part */
    block_len = byte_len & ~(SECTOR_SIZE-1);
    if (ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev, 
					  part_info.start+sector, 
					  block_len/SECTOR_SIZE, 
					  (unsigned long *)buf) != block_len/SECTOR_SIZE) 
        {
	printf (" ** ext2fs_devread() read error - block\n");
	return(0);
	}
    buf+=block_len;
    byte_len-=block_len;
    sector+= block_len/SECTOR_SIZE;

    if (byte_len != 0) 
        {
/*      read rest of data which are not in whole sector */
	if (ext2fs_block_dev_desc->block_read(ext2fs_block_dev_desc->dev,
					      part_info.start+sector, 
					      1, 
					      (unsigned long *)sec_buf) != 1) 
	    {
	    printf (" ** ext2fs_devread() read error - last part\n");
	    return(0);
	    }
	memcpy(buf, sec_buf, byte_len);
	}
    return(1);
    }
#endif /* CFG_CMD_EXT2FS */