xref: /freebsd/sbin/fsirand/fsirand.8 (revision 952d112864d8008aa87278a30a539d888a8493cd)
1.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
2.\" All rights reserved.
3.\"
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12.\" 3. All advertising materials mentioning features or use of this software
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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
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29.\"	$OpenBSD: fsirand.8,v 1.6 1997/02/23 03:58:26 millert Exp $
30.\"
31.Dd January 25, 1997
32.Dt FSIRAND 8
33.Os
34.Sh NAME
35.Nm fsirand
36.Nd randomize inode generation numbers
37.Sh SYNOPSIS
38.Nm fsirand
39.Op Fl b
40.Op Fl f
41.Op Fl p
42.Ar special
43.Op Ar "special ..."
44.Sh DESCRIPTION
45The
46.Nm fsirand
47command installs random generation numbers on all the inodes for
48each filesystem specified on the command line by
49.Ar special .
50This increases the security of NFS-exported filesystems by making
51it difficult to ``guess'' filehandles.
52.Pp
53.Em Note:
54.Xr newfs 8
55now does the equivalent of
56.Nm
57itself so it is no longer necessary to
58run
59.Nm
60by hand on a new filesystem.  It is only used to
61re-randomize or report on an existing filesystem.
62.Pp
63.Nm Fsirand
64should only be used on an unmounted filesystem that
65has been checked with
66.Xr fsck 8
67or a filesystem that is mounted read-only.
68.Nm Fsirand
69may be used on the root filesystem in single-user mode
70but the system should be rebooted via ``reboot -n'' afterwards.
71.Sh OPTIONS
72.Bl -tag -width indent
73The available options are as follows:
74.It Fl b
75Use the default block size (usually 512 bytes) instead
76of the value gleaned from the disklabel.
77.It Fl f
78Force
79.Nm
80to run even if the filesystem on
81.Ar special
82is not marked as clean.
83.It Fl p
84Print the current generation numbers for all inodes instead of
85generating new ones.
86.Sh CAVEATS
87Since
88.Nm
89allocates enough memory to hold all the inodes in
90a given cylinder group it is may use a large amount
91of memory for large disks with few cylinder groups.
92.Sh SEE ALSO
93.Xr fs 5 ,
94.Xr fsck 8 ,
95.Xr newfs 8 .
96.Sh HISTORY
97The
98.Nm
99command appeared in SunOS 3.x.
100.br
101This version of
102.Nm
103first appeared in
104.Ox 2.1 .
105A
106.Tn FreeBSD
107version first appeared in
108.Fx 2.2.5 .
109.Sh AUTHOR
110.nf
111Todd C. Miller <Todd.Miller@courtesan.com>
112.fi
113