src/sbin/mount_vnd/mount_vnd.8

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.Dd $Mdocdate: April 23 2020 $
.Dt MOUNT_VND 8
.Os
.Sh NAME
.Nm mount_vnd
.Nd mount vnode disks
.Sh SYNOPSIS
.Nm mount_vnd
.Op Fl k
.Op Fl K Ar rounds
.Op Fl o Ar options
.Op Fl S Ar saltfile
.Op Fl t Ar disktype
.Ar image vnd_dev
.Sh DESCRIPTION
.Nm mount_vnd
works similarly to
.Xr vnconfig 8 ,
but it provides an interface that can be used by the
.Xr fstab 5
infrastructure, so that an
.Ar image
file can be configured to a device
.Ar vnd_dev
while booting.
.Pp
For
.Xr fstab 5
lines with type
.Dq ffs ,
the
.Dq noauto
option must be set to prevent a
.Xr mount 8
of the FFS partitions
before the necessary vnd devices are configured.
Also, the
.Dq fs_passno
field has to be set to 0 to prevent
.Xr fsck 8
from checking the file system for the same reasons.
.Pp
.Nm mount_vnd
is invoked by
.Xr mount 8
when using the following syntax:
.Bd -ragged -offset 4n
.Nm mount Op options
-t vnd
.Ar image vnd_dev
.Ed
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl K Ar rounds
Associate an encryption key with the device.
All data will be encrypted using the Blowfish cipher before it is
written to the disk.
The user is asked for both a passphrase and the name of a salt file.
The salt file can also be specified on the command line using the
.Fl S
option.
The passphrase and salt are combined according to PKCS #5 PBKDF2 for the
specified number of
rounds to generate the actual key used.
.Ar rounds
is a number between 1000 and
.Dv INT_MAX .
DO NOT LOSE THE SALT FILE.
.It Fl k
Associate an encryption key with the device.
All data will be encrypted using the Blowfish cipher before it is
written to the disk.
.It Fl o Ar options
Options are specified with a
.Fl o
flag followed by a comma separated string of options.
See the
.Xr mount 8
man page for possible options and their meanings.
.Pp
At the moment,
.Fl o
is only here for compatibility reasons, but no use is made of supplied
options.
.It Fl S Ar saltfile
When
.Fl K
is used, specify the
.Pa saltfile .
.It Fl t Ar disktype
Specify a
.Ar disktype
entry from the
.Xr disktab 5
database.
The
.Ar vnd_dev
will have the sector size, sectors per track, and tracks per cylinder values
of the specified
.Ar disktype .
The defaults are 512-byte sectors, 100 sectors per track and 1 track per
cylinder.
.El
.Sh FILES
.Bl -tag -width /etc/rvnd?? -compact
.It Pa /dev/{,r}vnd*
.El
.Sh EXAMPLES
An example
.Xr fstab 5
entry is:
.Bd -literal -offset indent
/tmp/cryptimg /dev/vnd0c vnd rw,noauto,-k       0 0
/dev/vnd0a   /mnt        ffs rw,noauto          0 0
.Ed
.Pp
Mounting images during the first pass of
.Xr fsck 8
and
.Xr mount 8
is not possible, because the image to be configured to a vnd itself
resides on a file system that first has to be checked and mounted.
.Sh SEE ALSO
.Xr vnd 4 ,
.Xr disktab 5 ,
.Xr fstab 5 ,
.Xr mount 8 ,
.Xr swapon 8 ,
.Xr umount 8
.Sh HISTORY
The
.Nm
command first appeared in
.Ox 4.2 .