1.\" $NetBSD: extattrctl.8,v 1.2 2005/09/23 20:58:50 wiz 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 Xo 91.Cm initattr 92.Op Fl f 93.Op Fl p Ar path 94.Ar attrsize attrfile 95.Xc 96Create and initialize a file to use as an attribute backing file. 97You must specify a maximum per-inode size for the attribute in bytes in 98.Ar attrsize , 99as well as the file where the attribute will be stored, using 100.Ar attrfile . 101.Pp 102The 103.Fl f 104argument may be used to indicate that it is alright to overwrite an 105existing attribute backing file; otherwise, if the target file exists, 106an error will be returned. 107.Pp 108The 109.Fl p Ar path 110argument may be used to preallocate space for all attributes rather than 111relying on sparse files to conserve space. 112This has the advantage of guaranteeing that space will be available 113for attributes when they are written, preventing low disk space conditions 114from denying attribute service. 115.Pp 116This file should not exist before running 117.Cm initattr . 118.It Cm showattr Ar attrfile 119Show the attribute header values in the attribute file named by 120.Ar attrfile . 121.It Cm enable Ar path attrnamespace attrname attrfile 122Enable an attribute named 123.Ar attrname 124in the namespace 125.Ar attrnamespace 126on the file system identified using 127.Ar path , 128and backed by initialized attribute file 129.Ar attrfile . 130Available namespaces are 131.Dq user 132and 133.Dq system . 134The backing file must have been initialized using 135.Cm initattr 136before its first use. 137Attributes must have been started on the file system prior to the 138enabling of any attributes. 139.It Cm disable Ar path attrnamespace attrname 140Disable the attributed named 141.Ar attrname 142in namespace 143.Ar attrnamespace 144on the file system identified by 145.Ar path . 146Available namespaces are 147.Dq user 148and 149.Dq system . 150The file system must have attributes started on it, and the attribute 151most have been enabled using 152.Cm enable . 153.El 154.Pp 155The kernel also includes support for automatic starting of extended 156attributes on a file system at mount time once configured with 157.Nm . 158If the kernel is built with the 159.Dv UFS_EXTATTR_AUTOSTART 160option, UFS will search for a 161.Pa .attribute 162sub-directory of the file system root during the mount operation. 163If found, extended attribute support will be started for the file system. 164UFS will then search for 165.Pa system 166and 167.Pa user 168sub-directories of the 169.Pa .attribute 170directory for any potential backing files and enable an extended attribute 171for each valid backing file with the backing file name as the attribute 172name. 173.Sh EXAMPLES 174.Dl extattrctl start / 175.Pp 176Start extended attributes on the root file system. 177.Pp 178.Dl extattrctl initattr 17 /.attribute/system/md5 179.Pp 180Create an attribute backing file in 181.Pa /.attribute/system/md5 , 182and set the maximum size of each attribute to 17 bytes, with a 183sparse file used for storing the attributes. 184.Pp 185.Dl extattrctl enable / system md5 /.attribute/system/md5 186.Pp 187Enable an attribute named md5 on the root file system, backed from the file 188.Pa /.attribute/system/md5 . 189.Pp 190.Dl extattrctl disable / md5 191.Pp 192Disable the attribute named md5 on the root file system. 193.Pp 194.Dl extattrctl stop / 195.Pp 196Stop extended attributes on the root file system. 197.Sh SEE ALSO 198.Xr extattr_get_file 2 , 199.\" .Xr ffs 7 , 200.Xr getextattr 8 , 201.Xr extattr 9 202.Sh HISTORY 203Extended attribute support was developed as part of the TrustedBSD 204Project, and introduced in 205.Fx 5.0 206and 207.Nx 4.0 . 208It was developed to support security extensions requiring additional 209labels to be associated with each file or directory. 210.Sh AUTHORS 211.An Robert N M Watson 212.Sh BUGS 213.Nm 214works only on UFS1 file systems. 215The kernel support for extended attribute backing files and this 216control program should be generalized for any file system that 217lacks native extended attribute support. 218