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);
}
#ifdef CFG_EXT2_SUPPORT_DYNAMIC_REV
inodes_per_block = EXT2_BLOCK_SIZE (data) / ext2_inode_size;
#else
inodes_per_block = EXT2_BLOCK_SIZE (data) / 128;
#endif
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. */
#ifdef CFG_EXT2_SUPPORT_DYNAMIC_REV
status = ext2fs_devread (((__le32_to_cpu (blkgrp.inode_table_id) +
blkno) << LOG2_EXT2_BLOCK_SIZE (data)),
ext2_inode_size * blkoff,
sizeof (struct ext2_inode), (char *) inode);
#else
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);
#endif
if (status == 0) {
return (0);
}
return (1);
}
int ext2fs_read_file
(struct ext2fs_node *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_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));
}
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;
}
#ifdef CFG_EXT2_SUPPORT_DYNAMIC_REV
#ifdef DEBUG
printf("revision_level = 0x%x, inode_size = 0x%x\n", data->sblock.revision_level, data->sblock.inode_size);
#endif
if (__le32_to_cpu (data->sblock.revision_level) == EXT2_GOOD_OLD_REV) {
ext2_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
} else {
ext2_inode_size = __le16_to_cpu (data->sblock.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);
}
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);
}
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);
}
static int ext2fs_read_block(struct ext2fs_node *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) != indir2_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);
}
static int ext2fs_read_block (ext2fs_node_t node, int fileblock, int *stream) {
#else
static int ext2fs_read_block (ext2fs_node_t node, int fileblock) {
#endif
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;
#ifdef CFG_OPTIMIZE_EXT2_READ
*stream = 1;/* itself */
#endif
/* Direct blocks. */
if (fileblock < INDIRECT_BLOCKS) {
blknr = __le32_to_cpu (inode->b.blocks.dir_blocks[fileblock]);
#ifdef CFG_OPTIMIZE_EXT2_READ
while(((inode->b.blocks.dir_blocks[fileblock + 1] -
inode->b.blocks.dir_blocks[fileblock]) == 1) &&
(fileblock < INDIRECT_BLOCKS - 1)) {
fileblock++;
*stream += 1;
}
#endif
}
/* 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]);
#ifdef CFG_OPTIMIZE_EXT2_READ
while(((__le32_to_cpu (indir1_block[fileblock - INDIRECT_BLOCKS + 1]) - \
__le32_to_cpu (indir1_block[fileblock - INDIRECT_BLOCKS])) == 1) && (fileblock < (blksz - 1))) {
fileblock++;
*stream += 1;
}
#endif
}
/* 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);
#ifdef CFG_OPTIMIZE_EXT2_READ
int rbcnt = 0;
#endif
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]);
#ifdef CFG_OPTIMIZE_EXT2_READ
rbcnt = rblock % perblock;
while(((__le32_to_cpu (indir2_block[rbcnt + 1]) - \
__le32_to_cpu (indir2_block[rbcnt])) == 1) && (rbcnt < (blksz - 1))) {
rbcnt++;
*stream += 1;
}
#endif
}
/* 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);
}
#ifdef CFG_OPTIMIZE_EXT2_READ
int ext2fs_read_file
(ext2fs_node_t node, int pos, unsigned int len, char *buf) {
int log2blocksize = LOG2_EXT2_BLOCK_SIZE (node->data);
int blocksize = 1 << (log2blocksize + DISK_SECTOR_BITS);
unsigned int filesize = __le32_to_cpu(node->inode.size);
int blknr;
int blockend;
int status;
int remain = len;
char *buffer = buf;
int stream = 0;
int cur = pos / blocksize;
int blockoff = pos % blocksize;
/* Adjust len so it we can't read past the end of the file. */
if (len > filesize) {
len = filesize;
}
while (remain > 0) {
blknr = ext2fs_read_block (node, cur, &stream);
if (blknr < 0) {
return (-1);
}
blknr = blknr << log2blocksize;
if(remain < blocksize * stream) {
blockend = remain;
} else {
blockend = blocksize * stream;
}
status = ext2fs_devread (blknr, blockoff, blockend, buffer);
if (status == 0) {
return (-1);
}
remain -= blockend;
buffer += blockend;
cur += stream;
blockoff = 0;
if(remain == 0)
return (len);
else if(remain < 0)
return (-1);
}
return (len);
}
