1.\" $NetBSD: extattrctl.8,v 1.3 2009/03/11 18:05:37 joerg Exp $ 2.\" 3.\" Copyright (c) 2000-2001 Robert N. M. Watson 4.\" All rights reserved. 5.\" 6.\" This software was developed by Robert Watson for the TrustedBSD Project. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" $FreeBSD: src/usr.sbin/extattrctl/extattrctl.8,v 1.24 2005/02/09 18:04:40 ru Exp $ 30.\" 31.\" Developed by the TrustedBSD Project. 32.\" Support for file system extended attribute. 33.\" 34.Dd July 11, 2005 35.Dt EXTATTRCTL 8 36.Os 37.Sh NAME 38.Nm extattrctl 39.Nd manage UFS1 extended attributes 40.Sh SYNOPSIS 41.Nm 42.Cm start 43.Ar path 44.Nm 45.Cm stop 46.Ar path 47.Nm 48.Cm initattr 49.Op Fl f 50.Op Fl p Ar path 51.Ar attrsize 52.Ar attrfile 53.Nm 54.Cm showattr 55.Ar attrfile 56.Nm 57.Cm enable 58.Ar path 59.Ar attrnamespace 60.Ar attrname 61.Ar attrfile 62.Nm 63.Cm disable 64.Ar path 65.Ar attrnamespace 66.Ar attrname 67.Sh DESCRIPTION 68The 69.Nm 70utility 71is the management utility for extended attributes over the UFS1 file system. 72It allows the starting and stopping of extended attributes on a file system, 73as well as initialization of attribute backing files, and enabling and 74disabling of specific extended attributes on a file system. 75.Pp 76The first argument on the command line indicates the operation to be 77performed. 78Operation must be one of the following: 79.Bl -tag -width indent 80.It Cm start Ar path 81Start extended attribute support on the file system named using 82.Ar path . 83The file system must be a UFS1 file system, and the 84.Dv UFS_EXTATTR 85kernel option must have been enabled. 86.It Cm stop Ar path 87Stop extended attribute support on the file system named using 88.Ar path . 89Extended attribute support must previously have been started. 90.It Cm initattr Oo Fl f Oc Oo Fl p Ar path Oc Ar attrsize attrfile 91Create and initialize a file to use as an attribute backing file. 92You must specify a maximum per-inode size for the attribute in bytes in 93.Ar attrsize , 94as well as the file where the attribute will be stored, using 95.Ar attrfile . 96.Pp 97The 98.Fl f 99argument may be used to indicate that it is alright to overwrite an 100existing attribute backing file; otherwise, if the target file exists, 101an error will be returned. 102.Pp 103The 104.Fl p Ar path 105argument may be used to preallocate space for all attributes rather than 106relying on sparse files to conserve space. 107This has the advantage of guaranteeing that space will be available 108for attributes when they are written, preventing low disk space conditions 109from denying attribute service. 110.Pp 111This file should not exist before running 112.Cm initattr . 113.It Cm showattr Ar attrfile 114Show the attribute header values in the attribute file named by 115.Ar attrfile . 116.It Cm enable Ar path attrnamespace attrname attrfile 117Enable an attribute named 118.Ar attrname 119in the namespace 120.Ar attrnamespace 121on the file system identified using 122.Ar path , 123and backed by initialized attribute file 124.Ar attrfile . 125Available namespaces are 126.Dq user 127and 128.Dq system . 129The backing file must have been initialized using 130.Cm initattr 131before its first use. 132Attributes must have been started on the file system prior to the 133enabling of any attributes. 134.It Cm disable Ar path attrnamespace attrname 135Disable the attributed named 136.Ar attrname 137in namespace 138.Ar attrnamespace 139on the file system identified by 140.Ar path . 141Available namespaces are 142.Dq user 143and 144.Dq system . 145The file system must have attributes started on it, and the attribute 146most have been enabled using 147.Cm enable . 148.El 149.Pp 150The kernel also includes support for automatic starting of extended 151attributes on a file system at mount time once configured with 152.Nm . 153If the kernel is built with the 154.Dv UFS_EXTATTR_AUTOSTART 155option, UFS will search for a 156.Pa .attribute 157sub-directory of the file system root during the mount operation. 158If found, extended attribute support will be started for the file system. 159UFS will then search for 160.Pa system 161and 162.Pa user 163sub-directories of the 164.Pa .attribute 165directory for any potential backing files and enable an extended attribute 166for each valid backing file with the backing file name as the attribute 167name. 168.Sh EXAMPLES 169.Dl extattrctl start / 170.Pp 171Start extended attributes on the root file system. 172.Pp 173.Dl extattrctl initattr 17 /.attribute/system/md5 174.Pp 175Create an attribute backing file in 176.Pa /.attribute/system/md5 , 177and set the maximum size of each attribute to 17 bytes, with a 178sparse file used for storing the attributes. 179.Pp 180.Dl extattrctl enable / system md5 /.attribute/system/md5 181.Pp 182Enable an attribute named md5 on the root file system, backed from the file 183.Pa /.attribute/system/md5 . 184.Pp 185.Dl extattrctl disable / md5 186.Pp 187Disable the attribute named md5 on the root file system. 188.Pp 189.Dl extattrctl stop / 190.Pp 191Stop extended attributes on the root file system. 192.Sh SEE ALSO 193.Xr extattr_get_file 2 , 194.\" .Xr ffs 7 , 195.Xr getextattr 8 , 196.Xr extattr 9 197.Sh HISTORY 198Extended attribute support was developed as part of the TrustedBSD 199Project, and introduced in 200.Fx 5.0 201and 202.Nx 4.0 . 203It was developed to support security extensions requiring additional 204labels to be associated with each file or directory. 205.Sh AUTHORS 206.An Robert N M Watson 207.Sh BUGS 208.Nm 209works only on UFS1 file systems. 210The kernel support for extended attribute backing files and this 211control program should be generalized for any file system that 212lacks native extended attribute support. 213