ext2fs.c

/*
 * (C) Copyright 2004
 *  esd gmbh <www.esd-electronics.com>
 *  Reinhard Arlt <reinhard.arlt@esd-electronics.com>
 *
 *  based on code from grub2 fs/ext2.c and fs/fshelp.c by
 *
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2003, 2004  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 <common.h>

#if (CONFIG_COMMANDS & CFG_CMD_EXT2)
#include <ext2fs.h>
#include <malloc.h>
#include <asm/byteorder.h>

extern int ext2fs_devread (int sector, int byte_offset, int byte_len, char *buf);

/* Magic value used to identify an ext2 filesystem.  */
#define	EXT2_MAGIC		0xEF53
/* Amount of indirect blocks in an inode.  */
#define INDIRECT_BLOCKS		12
/* Maximum lenght of a pathname.  */
#define EXT2_PATH_MAX		4096
/* Maximum nesting of symlinks, used to prevent a loop.  */
#define	EXT2_MAX_SYMLINKCNT	8

/* Filetype used in directory entry.  */
#define	FILETYPE_UNKNOWN	0
#define	FILETYPE_REG		1
#define	FILETYPE_DIRECTORY	2
#define	FILETYPE_SYMLINK	7

/* Filetype information as used in inodes.  */
#define FILETYPE_INO_MASK	0170000
#define FILETYPE_INO_REG	0100000
#define FILETYPE_INO_DIRECTORY	0040000
#define FILETYPE_INO_SYMLINK	0120000

/* Bits used as offset in sector */
#define DISK_SECTOR_BITS        9

/* Log2 size of ext2 block in 512 blocks.  */
#define LOG2_EXT2_BLOCK_SIZE(data) (__le32_to_cpu (data->sblock.log2_block_size) + 1)

/* Log2 size of ext2 block in bytes.  */
#define LOG2_BLOCK_SIZE(data)	   (__le32_to_cpu (data->sblock.log2_block_size) + 10)

/* The size of an ext2 block in bytes.  */
#define EXT2_BLOCK_SIZE(data)	   (1 << LOG2_BLOCK_SIZE(data))

/* The ext2 superblock.  */
struct ext2_sblock
{
	uint32_t total_inodes;
	uint32_t total_blocks;
	uint32_t reserved_blocks;
	uint32_t free_blocks;
	uint32_t free_inodes;
	uint32_t first_data_block;
	uint32_t log2_block_size;
	uint32_t log2_fragment_size;
	uint32_t blocks_per_group;
	uint32_t fragments_per_group;
	uint32_t inodes_per_group;
	uint32_t mtime;
	uint32_t utime;
	uint16_t mnt_count;
	uint16_t max_mnt_count;
	uint16_t magic;
	uint16_t fs_state;
	uint16_t error_handling;
	uint16_t minor_revision_level;
	uint32_t lastcheck;
	uint32_t checkinterval;
	uint32_t creator_os;
	uint32_t revision_level;
	uint16_t uid_reserved;
	uint16_t gid_reserved;
	uint32_t first_inode;
	uint16_t inode_size;
	uint16_t block_group_number;
	uint32_t feature_compatibility;
	uint32_t feature_incompat;
	uint32_t feature_ro_compat;
	uint32_t unique_id[4];
	char volume_name[16];
	char last_mounted_on[64];
	uint32_t compression_info;
};

/* The ext2 blockgroup.  */
struct ext2_block_group
{
	uint32_t block_id;
	uint32_t inode_id;
	uint32_t inode_table_id;
	uint16_t free_blocks;
	uint16_t free_inodes;
	uint16_t pad;
	uint32_t reserved[3];
};

/* The ext2 inode.  */
struct ext2_inode
{
	uint16_t mode;
	uint16_t uid;
	uint32_t size;
	uint32_t atime;
	uint32_t ctime;
	uint32_t mtime;
	uint32_t dtime;
	uint16_t gid;
	uint16_t nlinks;
	uint32_t blockcnt;  /* Blocks of 512 bytes!! */
	uint32_t flags;
	uint32_t osd1;
	union
        {
		struct datablocks
		{
			uint32_t dir_blocks[INDIRECT_BLOCKS];
			uint32_t indir_block;
			uint32_t double_indir_block;
			uint32_t tripple_indir_block;
		} blocks;
		char symlink[60];
        } b;
	uint32_t version;
	uint32_t acl;
	uint32_t dir_acl;
	uint32_t fragment_addr;
	uint32_t osd2[3];
};

/* The header of an ext2 directory entry.  */
struct ext2_dirent
{
	uint32_t inode;
	uint16_t direntlen;
	uint8_t  namelen;
	uint8_t  filetype;
};

struct ext2fs_node
{
	struct ext2_data *data;
	struct ext2_inode inode;
	int               ino;
	int               inode_read;
};

/* Information about a "mounted" ext2 filesystem.  */
struct ext2_data
{
	struct ext2_sblock sblock;
	struct ext2_inode *inode;
	struct ext2fs_node diropen;
};


typedef struct ext2fs_node *ext2fs_node_t;

struct ext2_data *ext2fs_root  = NULL;
ext2fs_node_t     ext2fs_file  = NULL;
int               symlinknest  = 0;
uint32_t         *indir1_block = NULL;
int               indir1_size  = 0;
int               indir1_blkno = -1;
uint32_t         *indir2_block = NULL;
int               indir2_size  = 0;
int               indir2_blkno = -1;


static int ext2fs_blockgroup
(
	struct ext2_data         *data,
	int                      group,
	struct ext2_block_group *blkgrp
	)
{
#ifdef DEBUG
	printf("ext2fs read blockgroup\n");
#endif
	return(ext2fs_devread (((__le32_to_cpu (data->sblock.first_data_block) + 1) << LOG2_EXT2_BLOCK_SIZE (data)),
			       group * sizeof (struct ext2_block_group),
			       sizeof (struct ext2_block_group),
			       (char *) blkgrp));
}


static int ext2fs_read_inode
(
	struct ext2_data        *data,
	int                      ino,
	struct ext2_inode       *inode
	)
{
	struct ext2_block_group  blkgrp;
	struct ext2_sblock      *sblock = &data->sblock;
	int                      inodes_per_block;
	int                      status;

	unsigned int             blkno;
	unsigned int             blkoff;

	/* It is easier to calculate if the first inode is 0.  */
	ino--;
#ifdef DEBUG
	printf("ext2fs read inode %d\n", ino);
#endif
	status = ext2fs_blockgroup (data, ino / __le32_to_cpu(sblock->inodes_per_group), &blkgrp);
	if (status == 0)
        {
		return(0);
	}
	inodes_per_block = EXT2_BLOCK_SIZE (data) / 128;
	blkno =  (ino % __le32_to_cpu (sblock->inodes_per_group)) / inodes_per_block;
	blkoff = (ino % __le32_to_cpu (sblock->inodes_per_group)) % inodes_per_block;
#ifdef DEBUG
	printf("ext2fs read inode blkno %d blkoff %d\n", blkno, blkoff);
#endif
	/* Read the inode.  */
	status = ext2fs_devread(((__le32_to_cpu (blkgrp.inode_table_id) + blkno) << LOG2_EXT2_BLOCK_SIZE (data)),
				sizeof (struct ext2_inode) * blkoff,
				sizeof (struct ext2_inode),
				(char *) inode);
	if (status == 0)
        {
		return(0);
	}
	return(1);
}


void ext2fs_free_node
(
	ext2fs_node_t node,
	ext2fs_node_t currroot
	)
{
	if ((node != &ext2fs_root->diropen) && (node != currroot))
        {
		free (node);
	}
}


static int ext2fs_read_block
(
	ext2fs_node_t node,
	int           fileblock
	)
{
	struct ext2_data  *data       = node->data;
	struct ext2_inode *inode      = &node->inode;
	int                blknr;
	int                blksz      = EXT2_BLOCK_SIZE (data);
	int                log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
	int                status;

	/* Direct blocks.  */
	if (fileblock < INDIRECT_BLOCKS)
        {
		blknr = __le32_to_cpu (inode->b.blocks.dir_blocks[fileblock]);
        }
	/* Indirect.  */
	else if (fileblock < (INDIRECT_BLOCKS + (blksz/4)))
        {
		if (indir1_block == NULL)
		{
			indir1_block = (uint32_t *) malloc(blksz);
			if (indir1_block == NULL)
			{
				printf("** ext2fs read block (indir 1) malloc failed. **\n");
				return(-1);
			}
			indir1_size  = blksz;
			indir1_blkno = -1;
		}
		if (blksz != indir1_size)
		{
			free(indir1_block);
			indir1_block = NULL;
			indir1_size  = 0;
			indir1_blkno = -1;
			indir1_block = (uint32_t *) malloc(blksz);
			if (indir1_block == NULL)
			{
				printf("** ext2fs read block (indir 1) malloc failed. **\n");
				return(-1);
			}
			indir1_size  = blksz;
		}
		if ((__le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz) != indir1_blkno)
		{
			status = ext2fs_devread (__le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz, 0, blksz, (char *) indir1_block);
			if (status == 0)
			{
				printf("** ext2fs read block (indir 1) failed. **\n");
				return(0);
			}
			indir1_blkno = __le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz;
		}
		blknr = __le32_to_cpu(indir1_block[fileblock - INDIRECT_BLOCKS]);
	}
	/* Double indirect.  */
	else if (fileblock < (INDIRECT_BLOCKS + (blksz / 4 * (blksz  / 4 + 1))))
        {
		unsigned int perblock = blksz / 4;
		unsigned int rblock = fileblock - (INDIRECT_BLOCKS
						   + blksz / 4);

		if (indir1_block == NULL)
		{
			indir1_block = (uint32_t *) malloc(blksz);
			if (indir1_block == NULL)
			{
				printf("** ext2fs read block (indir 2 1) malloc failed. **\n");
				return(-1);
			}
			indir1_size  = blksz;
			indir1_blkno = -1;
		}
		if (blksz != indir1_size)
		{
			free(indir1_block);
			indir1_block = NULL;
			indir1_size  = 0;
			indir1_blkno = -1;
			indir1_block = (uint32_t *) malloc(blksz);
			if (indir1_block == NULL)
			{
				printf("** ext2fs read block (indir 2 1) malloc failed. **\n");
				return(-1);
			}
			indir1_size  = blksz;
		}
		if ((__le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz) != indir1_blkno)
		{
			status = ext2fs_devread (__le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz, 0, blksz, (char *) indir1_block);
			if (status == 0)
			{
				printf("** ext2fs read block (indir 2 1) failed. **\n");
				return(-1);
			}
			indir1_blkno = __le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz;
		}

		if (indir2_block == NULL)
		{
			indir2_block = (uint32_t *) malloc(blksz);
			if (indir2_block == NULL)
			{
				printf("** ext2fs read block (indir 2 2) malloc failed. **\n");
				return(-1);
			}
			indir2_size  = blksz;
			indir2_blkno = -1;
		}
		if (blksz != indir2_size)
		{
			free(indir2_block);
			indir2_block = NULL;
			indir2_size  = 0;
			indir2_blkno = -1;
			indir2_block = (uint32_t *) malloc(blksz);
			if (indir2_block == NULL)
			{
				printf("** ext2fs read block (indir 2 2) malloc failed. **\n");
				return(-1);
			}
			indir2_size  = blksz;
		}
		if ((__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz) != indir1_blkno)
		{
			status = ext2fs_devread(__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz, 0, blksz, (char *) indir2_block);
			if (status == 0)
			{
				printf("** ext2fs read block (indir 2 2) failed. **\n");
				return(-1);
			}
			indir2_blkno = __le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz;
		}
		blknr = __le32_to_cpu(indir2_block[rblock % perblock]);
	}
	/* Tripple indirect.  */
	else
        {
		printf("** ext2fs doesn't support tripple indirect blocks. **\n");
		return(-1);
        }
#ifdef DEBUG
	printf("ext2fs_read_block %08x\n", blknr);
#endif
	return(blknr);
}


int ext2fs_read_file
(
	ext2fs_node_t node,
	int           pos,
	unsigned int  len,
	char         *buf
	)
{
	int          i;
	int          blockcnt;
	int          log2blocksize = LOG2_EXT2_BLOCK_SIZE (node->data);
	int          blocksize     = 1 << (log2blocksize + DISK_SECTOR_BITS);
	unsigned int filesize      = node->inode.size;

	/* Adjust len so it we can't read past the end of the file.  */
	if (len > filesize)
        {
		len = filesize;
	}
	blockcnt = ((len + pos)  + blocksize - 1) / blocksize;

	for (i = pos / blocksize; i < blockcnt; i++)
        {
		int blknr;
		int blockoff = pos % blocksize;
		int blockend = blocksize;

		int skipfirst = 0;

		blknr = ext2fs_read_block(node, i);
		if (blknr < 0)
		{
			return(-1);
		}
		blknr = blknr << log2blocksize;

		/* Last block.  */
		if (i == blockcnt - 1)
		{
			blockend = (len + pos) % blocksize;

			/* The last portion is exactly blocksize.  */
			if (!blockend)
			{
				blockend = blocksize;
			}
		}

		/* First block.  */
		if (i == pos / blocksize)
		{
			skipfirst = blockoff;
			blockend -= skipfirst;
		}

		/* If the block number is 0 this block is not stored on disk but
		   is zero filled instead.  */
		if (blknr)
		{
			int status;

			status = ext2fs_devread (blknr, skipfirst, blockend, buf);
			if (status == 0)
			{
				return(-1);
			}
		}
		else
		{
			memset (buf, blocksize - skipfirst, 0);
		}
		buf += blocksize - skipfirst;
        }
	return(len);
}


static int ext2fs_iterate_dir
(
	ext2fs_node_t  dir,
	char          *name,
	ext2fs_node_t *fnode,
	int           *ftype
	)
{
	unsigned int fpos = 0;
	int          status;
	struct ext2fs_node *diro = (struct ext2fs_node *) dir;
#ifdef DEBUG
	if (name != NULL) printf("Iterate dir %s\n", name);
#endif /* of DEBUG */
	if (!diro->inode_read)
        {
		status = ext2fs_read_inode (diro->data, diro->ino, &diro->inode);
		if (status == 0)
		{
			return(0);
		}
	}
	/* Search the file.  */
	while (fpos < __le32_to_cpu (diro->inode.size))
        {
		struct ext2_dirent dirent;

		status = ext2fs_read_file (diro, fpos, sizeof (struct ext2_dirent), (char *) &dirent);
		if (status < 1)
		{
			return(0);
		}
		if (dirent.namelen != 0)
		{
			char               filename[dirent.namelen + 1];
			ext2fs_node_t      fdiro;
			int                type = FILETYPE_UNKNOWN;

			status = ext2fs_read_file (diro, fpos + sizeof (struct ext2_dirent), dirent.namelen, filename);
			if (status < 1)
			{
				return(0);
			}
			fdiro = malloc (sizeof (struct ext2fs_node));
			if (!fdiro)
			{
				return(0);
			}

			fdiro->data = diro->data;
			fdiro->ino  =  __le32_to_cpu(dirent.inode);

			filename[dirent.namelen] = '\0';

			if (dirent.filetype != FILETYPE_UNKNOWN)
			{
				fdiro->inode_read = 0;

				if (dirent.filetype == FILETYPE_DIRECTORY)
				{
					type = FILETYPE_DIRECTORY;
				}
				else if (dirent.filetype == FILETYPE_SYMLINK)
				{
					type = FILETYPE_SYMLINK;
				}
				else if (dirent.filetype == FILETYPE_REG)
				{
					type =  FILETYPE_REG;
				}
			}
			else
			{
				/* The filetype can not be read from the dirent, get it from inode */

				status = ext2fs_read_inode (diro->data, __le32_to_cpu (dirent.inode), &fdiro->inode);
				if (status == 0)
				{
					free(fdiro);
					return(0);
				}
				fdiro->inode_read = 1;

				if ((__le16_to_cpu (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY)
				{
					type = FILETYPE_DIRECTORY;
				}
				else if ((__le16_to_cpu (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
				{
					type = FILETYPE_SYMLINK;
				}
				else if ((__le16_to_cpu (fdiro->inode.mode) & FILETYPE_INO_MASK) == FILETYPE_INO_REG)
				{
					type = FILETYPE_REG;
				}
			}
#ifdef DEBUG
			printf("iterate >%s<\n", filename);
#endif /* of DEBUG */
			if ((name != NULL) && (fnode != NULL) && (ftype != NULL))
			{
				if(strcmp(filename, name) == 0)
				{
					*ftype = type;
					*fnode = fdiro;
					return(1);
				}
			}
			else
			{
				if (fdiro->inode_read == 0)
				{
					status = ext2fs_read_inode (diro->data, __le32_to_cpu (dirent.inode), &fdiro->inode);
					if (status == 0)
					{
						free(fdiro);
						return(0);
					}
					fdiro->inode_read = 1;
				}
				switch(type)
				{
				case FILETYPE_DIRECTORY:
					printf("<DIR> ");
					break;
				case FILETYPE_SYMLINK:
					printf("<SYM> ");
					break;
				case FILETYPE_REG:
					printf("      ");
					break;
				default:
					printf("<???> ");
					break;
				}
				printf("%10d %s\n", __le32_to_cpu(fdiro->inode.size), filename);
			}
			free(fdiro);
		}
		fpos += __le16_to_cpu (dirent.direntlen);
	}
	return(0);
}


static char *ext2fs_read_symlink
(
	ext2fs_node_t node
	)
{
	char               *symlink;
	struct ext2fs_node *diro = node;
	int                 status;

	if (!diro->inode_read)
        {
		status = ext2fs_read_inode (diro->data, diro->ino, &diro->inode);
		if (status == 0)
		{
			return(0);
		}
	}
	symlink = malloc (__le32_to_cpu (diro->inode.size) + 1);
	if (!symlink)
        {
		return(0);
	}
	/* If the filesize of the symlink is bigger than
	   60 the symlink is stored in a separate block,
	   otherwise it is stored in the inode.  */
	if (__le32_to_cpu (diro->inode.size) <= 60)
        {
		strncpy (symlink, diro->inode.b.symlink, __le32_to_cpu (diro->inode.size));
	}
	else
        {
		status = ext2fs_read_file (diro, 0, __le32_to_cpu (diro->inode.size), symlink);
		if (status == 0)
		{
			free (symlink);
			return(0);
		}
	}
	symlink[__le32_to_cpu (diro->inode.size)] = '\0';
	return(symlink);
}


int ext2fs_find_file1
(
	const char    *currpath,
	ext2fs_node_t  currroot,
	ext2fs_node_t *currfound,
	int           *foundtype
	)
{
	char           fpath[strlen (currpath) + 1];
	char          *name = fpath;
	char          *next;
	int            status;
	int            type     = FILETYPE_DIRECTORY;
	ext2fs_node_t  currnode = currroot;
	ext2fs_node_t  oldnode  = currroot;

	strncpy (fpath, currpath, strlen (currpath) + 1);

	/* Remove all leading slashes.  */
	while (*name == '/')
        {
		name++;
        }
	if (!*name)
	{
		*currfound = currnode;
		return(1);
	}

	for (;;)
	{
		int found;

		/* Extract the actual part from the pathname.  */
		next = strchr (name, '/');
		if (next)
		{
			/* Remove all leading slashes.  */
			while (*next == '/')
			{
				*(next++) = '\0';
			}
		}

		/* At this point it is expected that the current node is a directory, check if this is true.  */
		if (type != FILETYPE_DIRECTORY)
		{
			ext2fs_free_node (currnode, currroot);
			return(0);
		}

		oldnode = currnode;

		/* Iterate over the directory.  */
		found = ext2fs_iterate_dir (currnode, name, &currnode, &type);
		if (found == 0)
		{
			return(0);
		}
		if (found == -1)
		{
			break;
		}

		/* Read in the symlink and follow it.  */
		if (type == FILETYPE_SYMLINK)
		{
			char *symlink;

			/* Test if the symlink does not loop.  */
			if (++symlinknest == 8)
			{
				ext2fs_free_node (currnode, currroot);
				ext2fs_free_node (oldnode,  currroot);
				return(0);
			}

			symlink = ext2fs_read_symlink (currnode);
			ext2fs_free_node (currnode, currroot);

			if (!symlink)
			{
				ext2fs_free_node (oldnode, currroot);
				return(0);
			}
#ifdef DEBUG
			printf("Got symlink >%s<\n",symlink);
#endif /* of DEBUG */
			/* The symlink is an absolute path, go back to the root inode.  */
			if (symlink[0] == '/')
			{
				ext2fs_free_node (oldnode, currroot);
				oldnode = &ext2fs_root->diropen;
			}

			/* Lookup the node the symlink points to.  */
			status = ext2fs_find_file1 (symlink, oldnode, &currnode, &type);

			free (symlink);

			if (status == 0)
			{
				ext2fs_free_node (oldnode, currroot);
				return(0);
			}
		}

		ext2fs_free_node (oldnode, currroot);

		/* Found the node!  */
		if (!next || *next == '\0')
		{
			*currfound = currnode;
			*foundtype = type;
			return(1);
		}
		name = next;
	}
	return(-1);
}


int ext2fs_find_file
(
	const char    *path,
	ext2fs_node_t  rootnode,
	ext2fs_node_t *foundnode,
	int            expecttype
	)
{
	int status;
	int foundtype = FILETYPE_DIRECTORY;


	symlinknest = 0;
	if (!path || path[0] != '/')
        {
		return(0);
	}

	status = ext2fs_find_file1(path, rootnode, foundnode, &foundtype);
	if (status == 0)
        {
		return(0);
	}
	/* Check if the node that was found was of the expected type.  */
	if ((expecttype == FILETYPE_REG) && (foundtype != expecttype))
        {
		return(0);
	}
	else if ((expecttype == FILETYPE_DIRECTORY) && (foundtype != expecttype))
        {
		return(0);
	}
	return(1);
}


int ext2fs_ls
(
	char *dirname
	)
{
	ext2fs_node_t dirnode;
	int           status;

	if (ext2fs_root == NULL)
        {
		return(0);
	}

	status = ext2fs_find_file(dirname, &ext2fs_root->diropen, &dirnode, FILETYPE_DIRECTORY);
	if (status != 1)
        {
		printf("** Can not find directory. **\n");
		return(1);
        }
	ext2fs_iterate_dir(dirnode, NULL, NULL, NULL);
	ext2fs_free_node(dirnode, &ext2fs_root->diropen);
	return(0);
}


int ext2fs_open
(
	char *filename
	)
{
	ext2fs_node_t  fdiro = NULL;
	int            status;
	int            len;

	if (ext2fs_root == NULL)
        {
		return(0);
	}
	ext2fs_file = NULL;
	status      = ext2fs_find_file (filename, &ext2fs_root->diropen, &fdiro, FILETYPE_REG);
	if (status == 0)
        {
		goto fail;
	}
	if (!fdiro->inode_read)
        {
		status = ext2fs_read_inode (fdiro->data, fdiro->ino, &fdiro->inode);
		if (status == 0)
		{
			goto fail;
		}
	}
	len = __le32_to_cpu (fdiro->inode.size);
	ext2fs_file = fdiro;
	return(len);

 fail:
	ext2fs_free_node(fdiro, &ext2fs_root->diropen);
	return(0);
}


int ext2fs_close
(
	void
	)
{
	if ((ext2fs_file != NULL) && (ext2fs_root != NULL))
        {
		ext2fs_free_node(ext2fs_file, &ext2fs_root->diropen);
		ext2fs_file = NULL;
	}
	if (ext2fs_root != NULL)
	{
		free(ext2fs_root);
		ext2fs_root  = NULL;
	}
	if (indir1_block != NULL)
        {
		free(indir1_block);
		indir1_block =  NULL;
		indir1_size  =  0;
		indir1_blkno =  -1;
	}
	if (indir2_block != NULL)
        {
		free(indir2_block);
		indir2_block =  NULL;
		indir2_size  =  0;
		indir2_blkno =  -1;
	}
	return(0);
}


int ext2fs_read
(
	char     *buf,
	unsigned  len
	)
{
	int status;

	if (ext2fs_root == NULL)
        {
		return(0);
	}

	if (ext2fs_file == NULL)
        {
		return(0);
	}

	status = ext2fs_read_file(ext2fs_file, 0, len, buf);
	return(status);
}


int ext2fs_mount
(
	unsigned part_length
	)
{
	struct ext2_data *data;
	int               status;

	data = malloc (sizeof (struct ext2_data));
	if (!data)
        {
		return(0);
	}
	/* Read the superblock.  */
	status = ext2fs_devread (1 * 2, 0, sizeof (struct ext2_sblock), (char *) &data->sblock);
	if (status == 0)
        {
		goto fail;
	}
	/* Make sure this is an ext2 filesystem.  */
	if (__le16_to_cpu (data->sblock.magic) != EXT2_MAGIC)
        {
		goto fail;
	}
	data->diropen.data       =  data;
	data->diropen.ino        =  2;
	data->diropen.inode_read =  1;
	data->inode              = &data->diropen.inode;

	status = ext2fs_read_inode (data, 2, data->inode);
	if (status == 0)
        {
		goto fail;
	}

	ext2fs_root = data;

	return(1);

 fail:
	printf("Failed to mount ext2 filesystem...\n");
	free(data);
	ext2fs_root = NULL;