xref: /freebsd/sbin/fsirand/fsirand.8 (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
1.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
2.\" All rights reserved.
3.\"
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14.\"	This product includes software developed by Todd C. Miller.
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29.\"	$OpenBSD: fsirand.8,v 1.6 1997/02/23 03:58:26 millert Exp $
30.\" $FreeBSD$
31.\"
32.Dd January 25, 1997
33.Dt FSIRAND 8
34.Os
35.Sh NAME
36.Nm fsirand
37.Nd randomize inode generation numbers
38.Sh SYNOPSIS
39.Nm fsirand
40.Op Fl b
41.Op Fl f
42.Op Fl p
43.Ar special
44.Op Ar "special ..."
45.Sh DESCRIPTION
46The
47.Nm
48command installs random generation numbers on all the inodes for
49each filesystem specified on the command line by
50.Ar special .
51This increases the security of NFS-exported filesystems by making
52it difficult to ``guess'' filehandles.
53.Pp
54.Em Note Ns :
55.Xr newfs 8
56now does the equivalent of
57.Nm
58itself so it is no longer necessary to
59run
60.Nm
61by hand on a new filesystem.  It is only used to
62re-randomize or report on an existing filesystem.
63.Pp
64.Nm Fsirand
65should only be used on an unmounted filesystem that
66has been checked with
67.Xr fsck 8
68or a filesystem that is mounted read-only.
69.Nm Fsirand
70may be used on the root filesystem in single-user mode
71but the system should be rebooted via ``reboot -n'' afterwards.
72.Sh OPTIONS
73.Bl -tag -width indent
74The available options are as follows:
75.It Fl b
76Use the default block size (usually 512 bytes) instead
77of the value gleaned from the disklabel.
78.It Fl f
79Force
80.Nm
81to run even if the filesystem on
82.Ar special
83is not marked as clean.
84.It Fl p
85Print the current generation numbers for all inodes instead of
86generating new ones.
87.Sh CAVEATS
88Since
89.Nm
90allocates enough memory to hold all the inodes in
91a given cylinder group it may use a large amount
92of memory for large disks with few cylinder groups.
93.Sh SEE ALSO
94.Xr fs 5 ,
95.Xr fsck 8 ,
96.Xr newfs 8
97.Sh HISTORY
98The
99.Nm
100command appeared in SunOS 3.x.
101.br
102This version of
103.Nm
104first appeared in
105.Ox 2.1 .
106A
107.Bx Free
108version first appeared in
109.Fx 2.2.5 .
110.Sh AUTHORS
111.An Todd C. Miller Aq Todd.Miller@courtesan.com
112