1.\"- 2.\" Copyright (c) 1999 Robert N. M. Watson 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/share/man/man9/extattr.9,v 1.1.2.4 2001/12/17 11:30:18 ru Exp $ 27.\" $DragonFly: src/share/man/man9/extattr.9,v 1.2 2003/06/17 04:37:01 dillon Exp $ 28.\" 29.Dd December 23, 1999 30.Os 31.Dt EXTATTR 9 32.Sh NAME 33.Nm extattr 34.Nd virtual file system named extended attributes 35.Sh SYNOPSIS 36.In sys/param.h 37.In sys/vnode.h 38.In sys/extattr.h 39.Sh DESCRIPTION 40Named extended attributes allow additional meta-data to be associated 41with vnodes representing files and directories. The semantics of this 42additional data is that of a "name=value" pair, where a name may 43be defined or undefined, and if defined, associated with zero or more 44bytes of arbitrary binary data. Reads of this data may return specific 45contiguous regions of the meta-data, in the style of 46.Xr VOP_READ 9 , 47but writes will replace the entire current "value" associated with 48a given name. As there are a plethora of file systems with differing 49extended attributes, availability and functionality of these functions 50may be limited, and they should be used with awareness of the underlying 51semantics of the supporting file system. Authorization schemes for 52extended attribute data may also vary by file system, as well as 53maximum attribute size, and whether or not any or specific new attributes 54may be defined. 55.Pp 56Extended attributes are named using a null-terminated character string. 57Depending on file system semantics, this name may or may not be 58case-sensitive. Appropriate vnode extended attribute calls are: 59.Xr VOP_GETEXTATTR 9 60and 61.Xr VOP_SETEXTATTR 9 . 62.Sh SEE ALSO 63.Xr VFS 9 , 64.Xr VOP_GETEXTATTR 9 , 65.Xr VOP_SETEXTATTR 9 66.Sh AUTHORS 67This man page was written by 68.An Robert Watson . 69