xref: /dragonfly/sbin/fsirand/fsirand.8 (revision c3762235)
1.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
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11.\"    documentation and/or other materials provided with the distribution.
12.\" 3. All advertising materials mentioning features or use of this software
13.\"    must display the following acknowledgment:
14.\"	This product includes software developed by Todd C. Miller.
15.\" 4. The name of the author may not be used to endorse or promote products
16.\"    derived from this software without specific prior written permission.
17.\"
18.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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29.\"	$OpenBSD: fsirand.8,v 1.6 1997/02/23 03:58:26 millert Exp $
30.\" $FreeBSD: src/sbin/fsirand/fsirand.8,v 1.10.2.4 2003/02/23 20:17:15 trhodes Exp $
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
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
48utility installs random generation numbers on all the inodes for
49each file system specified on the command line by
50.Ar special .
51This increases the security of NFS-exported file systems by making
52it difficult to ``guess'' filehandles.
53.Pp
54.Em Note :
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 file system.  It is only used to
62re-randomize or report on an existing file system.
63.Pp
64The
65.Nm
66utility should only be used on an unmounted file system that
67has been checked with
68.Xr fsck 8
69or a file system that is mounted read-only.
70The
71.Nm
72utility may be used on the root file system in single-user mode
73but the system should be rebooted via ``reboot -n'' afterwards.
74.Sh OPTIONS
75The available options are as follows:
76.Bl -tag -width indent
77.It Fl b
78Use the default block size (usually 512 bytes) instead
79of the value gleaned from the disklabel.
80.It Fl f
81Force
82.Nm
83to run even if the file system on
84.Ar special
85is not marked as clean.
86.It Fl p
87Print the current generation numbers for all inodes instead of
88generating new ones.
89.El
90.Sh SEE ALSO
91.Xr fs 5 ,
92.Xr fsck 8 ,
93.Xr newfs 8
94.Sh HISTORY
95The
96.Nm
97utility appeared in SunOS 3.x.
98.Pp
99This version of
100.Nm
101first appeared in
102.Ox 2.1 .
103.Pp
104A
105.Fx
106version first appeared in
107.Fx 2.2.5 .
108.Sh AUTHORS
109.An Todd C. Miller Aq Mt Todd.Miller@courtesan.com
110.Sh CAVEATS
111Since
112.Nm
113allocates enough memory to hold all the inodes in
114a given cylinder group it may use a large amount
115of memory for large disks with few cylinder groups.
116