ext4_common.c

	}
	return 0;
}

static char *ext4fs_read_symlink(struct ext2fs_node *node)
{
	char *symlink;
	struct ext2fs_node *diro = node;
	int status;

	if (!diro->inode_read) {
		status = ext4fs_read_inode(diro->data, diro->ino, &diro->inode);
		if (status == 0)
			return 0;
	}
	symlink = zalloc(__le32_to_cpu(diro->inode.size) + 1);
	if (!symlink)
		return 0;

	if (__le32_to_cpu(diro->inode.size) <= 60) {
		strncpy(symlink, diro->inode.b.symlink,
			 __le32_to_cpu(diro->inode.size));
	} else {
		status = ext4fs_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;
}

static int ext4fs_find_file1(const char *currpath,
			     struct ext2fs_node *currroot,
			     struct ext2fs_node **currfound, int *foundtype)
{
	char fpath[strlen(currpath) + 1];
	char *name = fpath;
	char *next;
	int status;
	int type = FILETYPE_DIRECTORY;
	struct ext2fs_node *currnode = currroot;
	struct ext2fs_node *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';
		}

		if (type != FILETYPE_DIRECTORY) {
			ext4fs_free_node(currnode, currroot);
			return 0;
		}

		oldnode = currnode;

		/* Iterate over the directory. */
		found = ext4fs_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) {
				ext4fs_free_node(currnode, currroot);
				ext4fs_free_node(oldnode, currroot);
				return 0;
			}

			symlink = ext4fs_read_symlink(currnode);
			ext4fs_free_node(currnode, currroot);

			if (!symlink) {
				ext4fs_free_node(oldnode, currroot);
				return 0;
			}

			debug("Got symlink >%s<\n", symlink);

			if (symlink[0] == '/') {
				ext4fs_free_node(oldnode, currroot);
				oldnode = &ext4fs_root->diropen;
			}

			/* Lookup the node the symlink points to. */
			status = ext4fs_find_file1(symlink, oldnode,
						    &currnode, &type);

			free(symlink);

			if (status == 0) {
				ext4fs_free_node(oldnode, currroot);
				return 0;
			}
		}

		ext4fs_free_node(oldnode, currroot);

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

int ext4fs_find_file(const char *path, struct ext2fs_node *rootnode,
	struct ext2fs_node **foundnode, int expecttype)
{
	int status;
	int foundtype = FILETYPE_DIRECTORY;

	symlinknest = 0;
	if (!path)
		return 0;

	status = ext4fs_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 ext4fs_open(const char *filename)
{
	struct ext2fs_node *fdiro = NULL;
	int status;
	int len;

	if (ext4fs_root == NULL)
		return -1;

	ext4fs_file = NULL;
	status = ext4fs_find_file(filename, &ext4fs_root->diropen, &fdiro,
				  FILETYPE_REG);
	if (status == 0)
		goto fail;

	if (!fdiro->inode_read) {
		status = ext4fs_read_inode(fdiro->data, fdiro->ino,
				&fdiro->inode);
		if (status == 0)
			goto fail;
	}
	len = __le32_to_cpu(fdiro->inode.size);
	ext4fs_file = fdiro;

	return len;
fail:
	ext4fs_free_node(fdiro, &ext4fs_root->diropen);

	return -1;
}

int ext4fs_mount(unsigned part_length)
{
	struct ext2_data *data;
	int status;
	struct ext_filesystem *fs = get_fs();
	data = zalloc(sizeof(struct ext2_data));
	if (!data)
		return 0;

	/* Read the superblock. */
	status = ext4fs_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))
		fs->inodesz = 128;
	else
		fs->inodesz = __le16_to_cpu(data->sblock.inode_size);

	debug("EXT2 rev %d, inode_size %d\n",
	       __le32_to_cpu(data->sblock.revision_level), fs->inodesz);

	data->diropen.data = data;
	data->diropen.ino = 2;
	data->diropen.inode_read = 1;
	data->inode = &data->diropen.inode;

	status = ext4fs_read_inode(data, 2, data->inode);
	if (status == 0)
		goto fail;

	ext4fs_root = data;

	return 1;
fail:
	printf("Failed to mount ext2 filesystem...\n");
	free(data);
	ext4fs_root = NULL;

	return 0;
}