/*
 * (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>
#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 used_dir_cnt;
        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 unsigned int inode_size;


static int ext2fs_blockgroup
        (struct ext2_data *data, int group, struct ext2_block_group *blkgrp) {
        unsigned int blkno;
        unsigned int blkoff;
        unsigned int desc_per_blk;

        desc_per_blk = EXT2_BLOCK_SIZE(data) / sizeof(struct ext2_block_group);

        blkno = __le32_to_cpu(data->sblock.first_data_block) + 1 +
        group / desc_per_blk;
        blkoff = (group % desc_per_blk) * sizeof(struct ext2_block_group);
#ifdef DEBUG
        printf ("ext2fs read %d group descriptor (blkno %d blkoff %d)\n",
                group, blkno, blkoff);
#endif
        return (ext2fs_devread (blkno << LOG2_EXT2_BLOCK_SIZE(data),
                blkoff, 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;

#ifdef DEBUG
        printf ("ext2fs read inode %d, inode_size %d\n", ino, inode_size);
#endif
        /* It is easier to calculate if the first inode is 0.  */
        ino--;
        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) / inode_size;

        blkno = __le32_to_cpu (blkgrp.inode_table_id) +
                (ino % __le32_to_cpu (sblock->inodes_per_group))
                / inodes_per_block;
        blkoff = (ino % inodes_per_block) * inode_size;
#ifdef DEBUG
        printf ("ext2fs read inode blkno %d blkoff %d\n", blkno, blkoff);
#endif
        /* Read the inode.  */
        status = ext2fs_devread (blkno << LOG2_EXT2_BLOCK_SIZE (data), 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 = __le32_to_cpu(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, 0, blocksize - skipfirst);
                }
                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) {
                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 (-1);
        }
        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 (-1);
}


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;
        }
        if (__le32_to_cpu(data->sblock.revision_level == 0)) {
                inode_size = 128;
        } else {
                inode_size = __le16_to_cpu(data->sblock.inode_size);
        }
#ifdef DEBUG
        printf("EXT2 rev %d, inode_size %d\n",
                        __le32_to_cpu(data->sblock.revision_level), inode_size);
#endif
        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;
        return (0);
}