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.\" $FreeBSD$ 27.\" 28.Dd December 23, 1999 29.Os 30.Dt EXTATTR 9 31.Sh NAME 32.Nm extattr 33.Nd virtual file system named extended attributes 34.Sh SYNOPSIS 35.Fd #include <sys/param.h> 36.Fd #include <sys/vnode.h> 37.Fd #include <sys/extattr.h> 38.Sh DESCRIPTION 39Named extended attributes allow additional meta-data to be associated 40with vnodes representing files and directories. The semantics of this 41additional data is that of a "name=value" pair, where a name may 42be defined or undefined, and if defined, associated with zero or more 43bytes of arbitrary binary data. Reads of this data may return specific 44contiguous regions of the meta-data, in the style of 45.Xr VOP_READ 9 , 46but writes will replace the entire current "value" associated with 47a given name. As there are a plethora of file systems with differing 48extended attributes, availability and functionality of these functions 49may be limited, and they should be used with awareness of the underlying 50semantics of the supporting file system. Authorization schemes for 51extended attribute data may also vary by file system, as well as 52maximum attribute size, and whether or not any or specific new attributes 53may be defined. 54 55Extended attributes are named using a null-terminated character string. 56Depending on file system semantics, this name may or may not be 57case-sensitive. Appropriate vnode extended attribute calls are: 58.Xr VOP_GETEXTATTR 9 59and 60.Xr VOP_SETEXTATTR 9 . 61.Sh SEE ALSO 62.Xr VFS 9 , 63.Xr VOP_GETEXTATTR 9 , 64.Xr VOP_SETEXTATTR 9 . 65.Sh AUTHORS 66This man page was written by 67.An Robert Watson . 68