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VND(4) Device Drivers Manual VND(4)

NAME

vndvnode disk driver

SYNOPSIS

pseudo-device vnd [count]

DESCRIPTION

The vnd driver provides a disk-like interface to a file. This is useful for a variety of applications, such as building miniroot or floppy disk images.
This document assumes familiarity with how to generate kernels and how to properly configure disks and pseudo-devices in a kernel configuration file.
In order to compile in support for vnd devices, a line similar to the following must be present in the kernel configuration file:
pseudo-device	vnd	4	# vnode disk driver
The count argument is how many vnds memory is allocated for at boot time. In this example, no more than 4 vnds may be configured.
There is a run-time utility that is used for configuring vnds. See vnconfig(8) for more information.

IOCTL INTERFACE

The following ioctl(2) calls are defined in <dev/vndioctl.h>:
 
 
VNDIOCSET struct vnd_ioctl *
Associate the file vnd_file with a vnd pseudo device, optionally encrypted using the Blowfish cipher and the key specified in vnd_key of length vnd_keylen. The size of the configured device is returned in vnd_size.
struct vnd_ioctl { 
	char	*vnd_file; 
	off_t	vnd_size; 
	u_char	*vnd_key; 
	int	vnd_keylen; 
};
    
 
 
VNDIOCCLR struct vnd_ioctl *
Disassociate a vnd device.
 
 
VNDIOCGET struct vnd_user *
Get the associated file name, device, inode number, and unit number of a vnd device. If vnu_unit is -1, information on the vnd device corresponding to the file descriptor passed to ioctl(2) will be returned. Otherwise, vnu_unit may contain the unit number of another vnd device. This allows for opening just vnd0 and querying all available devices.
struct vnd_user { 
	char	vnufile[VNDNLEN]; 
	int	vnu_unit; 
	dev_t	vnu_dev; 
	ino_t	vnu_ino; 
};
    
Additionally, some disklabel(8) related ioctl(2) calls defined in <sys/dkio.h> are available: DIOCGDINFO, DIOCSDINFO, and DIOCWDINFO. They are documented in sd(4).

FILES

/dev/{,r}vnd*
vnd device special files

SEE ALSO

ioctl(2), sd(4), disklabel(5), config(8), disklabel(8), fdisk(8), fsck(8), MAKEDEV(8), mount(8), newfs(8), vnconfig(8)
July 2, 2014 OpenBSD-current