xref: /freebsd/sbin/fsirand/fsirand.8 (revision b2c76c41be32f904179efed29c0ca04d53f3996c)

.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
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.\"	$OpenBSD: fsirand.8,v 1.6 1997/02/23 03:58:26 millert Exp $
.\"
.Dd January 25, 1997
.Dt FSIRAND 8
.Os
.Sh NAME
.Nm fsirand
.Nd randomize inode generation numbers
.Sh SYNOPSIS
.Nm
.Op Fl b
.Op Fl f
.Op Fl p
.Ar special
.Op Ar "special ..."
.Sh DESCRIPTION
The
.Nm
utility installs random generation numbers on all the inodes for
each file system specified on the command line by
.Ar special .
This increases the security of NFS-exported file systems by making
it difficult to ``guess'' filehandles.
.Pp
.Em Note :
.Xr newfs 8
now does the equivalent of
.Nm
itself so it is no longer necessary to
run
.Nm
by hand on a new file system.
It is only used to
re-randomize or report on an existing file system.
.Pp
The
.Nm
utility should only be used on an unmounted file system that
has been checked with
.Xr fsck 8
or a file system that is mounted read-only.
The
.Nm
utility may be used on the root file system in single-user mode
but the system should be rebooted via ``reboot -n'' afterwards.
.Sh OPTIONS
The available options are as follows:
.Bl -tag -width indent
.It Fl b
Use the default block size (usually 512 bytes) instead
of the value gleaned from the disklabel.
.It Fl f
Force
.Nm
to run even if the file system on
.Ar special
is not marked as clean.
.It Fl p
Print the current generation numbers for all inodes instead of
generating new ones.
.El
.Sh SEE ALSO
.Xr fs 5 ,
.Xr fsck 8 ,
.Xr newfs 8
.Sh HISTORY
The
.Nm
utility appeared in SunOS 3.x.
.Pp
This version of
.Nm
first appeared in
.Ox 2.1 .
.Pp
A
.Fx
version first appeared in
.Fx 2.2.5 .
.Sh AUTHORS
.An Todd C. Miller Aq Mt Todd.Miller@courtesan.com
.Sh CAVEATS
Since
.Nm
allocates enough memory to hold all the inodes in
a given cylinder group it may use a large amount
of memory for large disks with few cylinder groups.