1.\" $OpenBSD: fsirand.8,v 1.31 2015/11/23 19:44:57 mmcc Exp $ 2.\" 3.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: November 23 2015 $ 18.Dt FSIRAND 8 19.Os 20.Sh NAME 21.Nm fsirand 22.Nd randomize inode generation numbers 23.Sh SYNOPSIS 24.Nm fsirand 25.Op Fl bfp 26.Ar special ... 27.Sh DESCRIPTION 28The 29.Nm 30command installs random generation numbers on all the inodes for 31each filesystem specified on the command line by 32.Ar special . 33This increases the security of NFS-exported filesystems by making 34it difficult to 35.Dq guess 36filehandles. 37.Pp 38.Em Note : 39.Xr newfs 8 40now does the equivalent of 41.Nm 42itself so it is no longer necessary to 43run 44.Nm 45by hand on a new filesystem. 46It is only used to re-randomize or report on an existing filesystem. 47.Pp 48.Nm 49should only be used on an unmounted filesystem that 50has been checked with 51.Xr fsck 8 52or a filesystem that is mounted read-only. 53.Nm 54may be used on the root filesystem in single-user mode 55but the system should be rebooted via 56.Dq reboot -n 57afterwards. 58.Pp 59The options are as follows: 60.Bl -tag -width Ds 61.It Fl b 62Use the default block size (usually 512 bytes) instead 63of the value gleaned from the disklabel. 64.It Fl f 65Force 66.Nm 67to run even if the filesystem on 68.Ar special 69is not marked as clean. 70.It Fl p 71Print the current generation numbers for all inodes instead of 72generating new ones. 73.El 74.Sh SEE ALSO 75.Xr fs 5 , 76.Xr fsck 8 , 77.Xr newfs 8 , 78.Xr reboot 8 79.Sh HISTORY 80The 81.Nm 82command appeared in SunOS 3.x. 83This version of 84.Nm 85first appeared in 86.Ox 2.1 . 87.Sh AUTHORS 88.An Todd C. Miller 89.Sh CAVEATS 90Since 91.Nm 92allocates enough memory to hold all the inodes in 93a given cylinder group, it may use a large amount 94of memory for large disks with few cylinder groups. 95