loop.c-2.2.original

Fast and transparent file system and swap encryption package for linux. No source code changes to li

		lo->lo_device = inode->i_rdev;
		lo->lo_flags = 0;

		/* Backed by a block device - don't need to hold onto
		   a file structure */
		lo->lo_backing_file = NULL;
	} else if (S_ISREG(inode->i_mode)) {
		if (!inode->i_op->bmap) { 
			printk(KERN_ERR "loop: device has no block access/not implemented\n");
			goto out_putf;
		}

		/* Backed by a regular file - we need to hold onto
		   a file structure for this file.  We'll use it to
		   write to blocks that are not already present in 
		   a sparse file.  We create a new file structure
		   based on the one passed to us via 'arg'.  This is
		   to avoid changing the file structure that the
		   caller is using */

		lo->lo_device = inode->i_dev;
		lo->lo_flags = LO_FLAGS_DO_BMAP;

		error = -ENFILE;
		lo->lo_backing_file = get_empty_filp();
		if (lo->lo_backing_file) {
			lo->lo_backing_file->f_mode = file->f_mode;
			lo->lo_backing_file->f_pos = file->f_pos;
			lo->lo_backing_file->f_flags = file->f_flags;
			lo->lo_backing_file->f_owner = file->f_owner;
			lo->lo_backing_file->f_dentry = file->f_dentry;
			lo->lo_backing_file->f_op = file->f_op;
			lo->lo_backing_file->private_data = file->private_data;

			error = get_write_access(inode);
			if (error) {
				put_filp(lo->lo_backing_file);
				lo->lo_backing_file = NULL;
			}
		}
	}
	if (error)
		goto out_putf;

	if (IS_RDONLY (inode) || is_read_only(lo->lo_device)) {
		lo->lo_flags |= LO_FLAGS_READ_ONLY;
		set_device_ro(dev, 1);
	} else {
		invalidate_inode_pages (inode);
		set_device_ro(dev, 0);
	}

	lo->lo_dentry = dget(file->f_dentry);
	lo->transfer = NULL;
	lo->ioctl = NULL;
	figure_loop_size(lo);

out_putf:
	fput(file);
out:
	if (error)
		MOD_DEC_USE_COUNT;
	return error;
}

static int loop_release_xfer(struct loop_device *lo)
{
	int err = 0; 
	if (lo->lo_encrypt_type) {
		struct loop_func_table *xfer= xfer_funcs[lo->lo_encrypt_type]; 
		if (xfer && xfer->release)
			err = xfer->release(lo); 
		if (xfer && xfer->unlock)
			xfer->unlock(lo); 
		lo->lo_encrypt_type = 0;
	}
	return err;
}

static int loop_init_xfer(struct loop_device *lo, int type,struct loop_info *i)
{
	int err = 0; 
	if (type) {
		struct loop_func_table *xfer = xfer_funcs[type]; 
		if (xfer->init)
			err = xfer->init(lo, i);
		if (!err) { 
			lo->lo_encrypt_type = type;
			if (xfer->lock)
				xfer->lock(lo);
		}
	}
	return err;
}  

static int loop_clr_fd(struct loop_device *lo, kdev_t dev)
{
	struct dentry *dentry = lo->lo_dentry;

	if (!dentry)
		return -ENXIO;
	if (lo->lo_refcnt > 1)	/* we needed one fd for the ioctl */
		return -EBUSY;

	if (S_ISBLK(dentry->d_inode->i_mode))
		blkdev_release (dentry->d_inode);
	lo->lo_dentry = NULL;

	if (lo->lo_backing_file != NULL) {
		fput(lo->lo_backing_file);
		lo->lo_backing_file = NULL;
	} else {
		dput(dentry);
	}

	loop_release_xfer(lo);
	lo->transfer = NULL;
	lo->ioctl = NULL;
	lo->lo_device = 0;
	lo->lo_encrypt_type = 0;
	lo->lo_offset = 0;
	lo->lo_encrypt_key_size = 0;
	memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
	memset(lo->lo_name, 0, LO_NAME_SIZE);
	loop_sizes[lo->lo_number] = 0;
	invalidate_buffers(dev);
	MOD_DEC_USE_COUNT;
	return 0;
}

static int loop_set_status(struct loop_device *lo, struct loop_info *arg)
{
	struct loop_info info; 
	int err;
	unsigned int type;

	if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid && 
	    !capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (!lo->lo_dentry)
		return -ENXIO;
	if (copy_from_user(&info, arg, sizeof (struct loop_info)))
		return -EFAULT; 
	if ((unsigned int) info.lo_encrypt_key_size > LO_KEY_SIZE)
		return -EINVAL;
	type = info.lo_encrypt_type; 
	if (type >= MAX_LO_CRYPT || xfer_funcs[type] == NULL)
		return -EINVAL;
	err = loop_release_xfer(lo);
	if (!err) 
		err = loop_init_xfer(lo, type, &info);
	if (err)
		return err;	

	lo->lo_offset = info.lo_offset;
	strncpy(lo->lo_name, info.lo_name, LO_NAME_SIZE);

	lo->transfer = xfer_funcs[type]->transfer;
	lo->ioctl = xfer_funcs[type]->ioctl;
	lo->lo_encrypt_key_size = info.lo_encrypt_key_size;
	lo->lo_init[0] = info.lo_init[0];
	lo->lo_init[1] = info.lo_init[1];
	if (info.lo_encrypt_key_size) {
		memcpy(lo->lo_encrypt_key, info.lo_encrypt_key, 
		       info.lo_encrypt_key_size);
		lo->lo_key_owner = current->uid; 
	}	
	figure_loop_size(lo);
	return 0;
}

static int loop_get_status(struct loop_device *lo, struct loop_info *arg)
{
	struct loop_info	info;

	if (!lo->lo_dentry)
		return -ENXIO;
	if (!arg)
		return -EINVAL;
	memset(&info, 0, sizeof(info));
	info.lo_number = lo->lo_number;
	info.lo_device = kdev_t_to_nr(lo->lo_dentry->d_inode->i_dev);
	info.lo_inode = lo->lo_dentry->d_inode->i_ino;
	info.lo_rdevice = kdev_t_to_nr(lo->lo_device);
	info.lo_offset = lo->lo_offset;
	info.lo_flags = lo->lo_flags;
	strncpy(info.lo_name, lo->lo_name, LO_NAME_SIZE);
	info.lo_encrypt_type = lo->lo_encrypt_type;
	if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
		info.lo_encrypt_key_size = lo->lo_encrypt_key_size;
		memcpy(info.lo_encrypt_key, lo->lo_encrypt_key,
		       lo->lo_encrypt_key_size);
	}
	return copy_to_user(arg, &info, sizeof(info)) ? -EFAULT : 0;
}

static int lo_ioctl(struct inode * inode, struct file * file,
	unsigned int cmd, unsigned long arg)
{
	struct loop_device *lo;
	int dev;

	if (!inode)
		return -EINVAL;
	if (MAJOR(inode->i_rdev) != MAJOR_NR) {
		printk(KERN_WARNING "lo_ioctl: pseudo-major != %d\n", MAJOR_NR);
		return -ENODEV;
	}
	dev = MINOR(inode->i_rdev);
	if (dev >= MAX_LOOP)
		return -ENODEV;
	lo = &loop_dev[dev];
	switch (cmd) {
	case LOOP_SET_FD:
		return loop_set_fd(lo, inode->i_rdev, arg);
	case LOOP_CLR_FD:
		return loop_clr_fd(lo, inode->i_rdev);
	case LOOP_SET_STATUS:
		return loop_set_status(lo, (struct loop_info *) arg);
	case LOOP_GET_STATUS:
		return loop_get_status(lo, (struct loop_info *) arg);
	case BLKGETSIZE:   /* Return device size */
		if (!lo->lo_dentry)
			return -ENXIO;
		if (!arg)
			return -EINVAL;
		return put_user(loop_sizes[lo->lo_number] << 1, (long *) arg);
	default:
		return lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
	}
	return 0;
}

static int lo_open(struct inode *inode, struct file *file)
{
	struct loop_device *lo;
	int	dev, type;


	if (!inode)
		return -EINVAL;
	if (MAJOR(inode->i_rdev) != MAJOR_NR) {
		printk(KERN_WARNING "lo_open: pseudo-major != %d\n", MAJOR_NR);
		return -ENODEV;
	}
	dev = MINOR(inode->i_rdev);
	if (dev >= MAX_LOOP) {
		return -ENODEV;
	}
	lo = &loop_dev[dev];

	type = lo->lo_encrypt_type; 
	if (type && xfer_funcs[type] && xfer_funcs[type]->lock)
		xfer_funcs[type]->lock(lo);
	lo->lo_refcnt++;
	MOD_INC_USE_COUNT;
	return 0;
}

static int lo_release(struct inode *inode, struct file *file)
{
	struct loop_device *lo;
	int	dev, err;

	if (!inode)
		return 0;
	if (MAJOR(inode->i_rdev) != MAJOR_NR) {
		printk(KERN_WARNING "lo_release: pseudo-major != %d\n", MAJOR_NR);
		return 0;
	}
	dev = MINOR(inode->i_rdev);
	if (dev >= MAX_LOOP)
		return 0;
	err = fsync_dev(inode->i_rdev);
	lo = &loop_dev[dev];
	if (lo->lo_refcnt <= 0)
		printk(KERN_ERR "lo_release: refcount(%d) <= 0\n", lo->lo_refcnt);
	else  {
		int type  = lo->lo_encrypt_type;
		--lo->lo_refcnt;
		if (xfer_funcs[type] && xfer_funcs[type]->unlock)
			xfer_funcs[type]->unlock(lo);
		MOD_DEC_USE_COUNT;
	}
	return err;
}

static struct file_operations lo_fops = {
	NULL,			/* lseek - default */
	block_read,		/* read - general block-dev read */
	block_write,		/* write - general block-dev write */
	NULL,			/* readdir - bad */
	NULL,			/* poll */
	lo_ioctl,		/* ioctl */
	NULL,			/* mmap */
	lo_open,		/* open */
	NULL,			/* flush */
	lo_release		/* release */
};

/*
 * And now the modules code and kernel interface.
 */
#ifdef MODULE
#define loop_init init_module
#endif

int loop_register_transfer(struct loop_func_table *funcs)
{
	if ((unsigned)funcs->number > MAX_LO_CRYPT || xfer_funcs[funcs->number])
		return -EINVAL;
	xfer_funcs[funcs->number] = funcs;
	return 0; 
}

int loop_unregister_transfer(int number)
{
	struct loop_device *lo; 

	if ((unsigned)number >= MAX_LO_CRYPT)
		return -EINVAL; 
	for (lo = &loop_dev[0]; lo < &loop_dev[MAX_LOOP]; lo++) { 
		int type = lo->lo_encrypt_type;
		if (type == number) { 
			xfer_funcs[type]->release(lo);
			lo->transfer = NULL; 
			lo->lo_encrypt_type = 0; 
		}
	}
	xfer_funcs[number] = NULL; 
	return 0; 
}

EXPORT_SYMBOL(loop_register_transfer);
EXPORT_SYMBOL(loop_unregister_transfer);

int __init loop_init(void) 
{
	int	i;

	if (register_blkdev(MAJOR_NR, "loop", &lo_fops)) {
		printk(KERN_WARNING "Unable to get major number %d for loop device\n",
		       MAJOR_NR);
		return -EIO;
	}
#ifndef MODULE
	printk(KERN_INFO "loop: registered device at major %d\n", MAJOR_NR);
#endif

	blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
	for (i=0; i < MAX_LOOP; i++) {
		memset(&loop_dev[i], 0, sizeof(struct loop_device));
		loop_dev[i].lo_number = i;
	}
	memset(&loop_sizes, 0, sizeof(loop_sizes));
	memset(&loop_blksizes, 0, sizeof(loop_blksizes));
	blk_size[MAJOR_NR] = loop_sizes;
	blksize_size[MAJOR_NR] = loop_blksizes;

	return 0;
}

#ifdef MODULE
void cleanup_module(void) 
{
	if (unregister_blkdev(MAJOR_NR, "loop") != 0)
		printk(KERN_WARNING "loop: cannot unregister blkdev\n");
}
#endif