xref: /freebsd/share/man/man9/extattr.9 (revision 3136363f3e45f1410cd58f04eab9be9713b9008e)
132900e82SRobert Watson.\"-
232900e82SRobert Watson.\" Copyright (c) 1999 Robert N. M. Watson
332900e82SRobert Watson.\" All rights reserved.
432900e82SRobert Watson.\"
532900e82SRobert Watson.\" Redistribution and use in source and binary forms, with or without
632900e82SRobert Watson.\" modification, are permitted provided that the following conditions
732900e82SRobert Watson.\" are met:
832900e82SRobert Watson.\" 1. Redistributions of source code must retain the above copyright
932900e82SRobert Watson.\"    notice, this list of conditions and the following disclaimer.
1032900e82SRobert Watson.\" 2. Redistributions in binary form must reproduce the above copyright
1132900e82SRobert Watson.\"    notice, this list of conditions and the following disclaimer in the
1232900e82SRobert Watson.\"    documentation and/or other materials provided with the distribution.
1332900e82SRobert Watson.\"
1432900e82SRobert Watson.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
1532900e82SRobert Watson.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1632900e82SRobert Watson.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1732900e82SRobert Watson.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
1832900e82SRobert Watson.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1932900e82SRobert Watson.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2032900e82SRobert Watson.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2132900e82SRobert Watson.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2232900e82SRobert Watson.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2332900e82SRobert Watson.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2432900e82SRobert Watson.\" SUCH DAMAGE.
2532900e82SRobert Watson.\"
2632900e82SRobert Watson.\"       $FreeBSD$
2732900e82SRobert Watson.\"
2832900e82SRobert Watson.Dd December 23, 1999
2932900e82SRobert Watson.Os
3032900e82SRobert Watson.Dt EXTATTR 9
3132900e82SRobert Watson.Sh NAME
3232900e82SRobert Watson.Nm extattr
3332900e82SRobert Watson.Nd virtual file system named extended attributes
3432900e82SRobert Watson.Sh SYNOPSIS
3532900e82SRobert Watson.Fd #include <sys/param.h>
3632900e82SRobert Watson.Fd #include <sys/vnode.h>
3732900e82SRobert Watson.Fd #include <sys/extattr.h>
3832900e82SRobert Watson.Sh DESCRIPTION
3932900e82SRobert WatsonNamed extended attributes allow additional meta-data to be associated
4032900e82SRobert Watsonwith vnodes representing files and directories.  The semantics of this
4132900e82SRobert Watsonadditional data is that of a "name=value" pair, where a name may
4232900e82SRobert Watsonbe defined or undefined, and if defined, associated with zero or more
4332900e82SRobert Watsonbytes of arbitrary binary data.  Reads of this data may return specific
4432900e82SRobert Watsoncontiguous regions of the meta-data, in the style of
4532900e82SRobert Watson.Xr VOP_READ 9 ,
4632900e82SRobert Watsonbut writes will replace the entire current "value" associated with
4732900e82SRobert Watsona given name.  As there are a plethora of file systems with differing
4832900e82SRobert Watsonextended attributes, availability and functionality of these functions
4932900e82SRobert Watsonmay be limited, and they should be used with awareness of the underlying
5032900e82SRobert Watsonsemantics of the supporting file system.  Authorization schemes for
5132900e82SRobert Watsonextended attribute data may also vary by file system, as well as
5232900e82SRobert Watsonmaximum attribute size, and whether or not any or specific new attributes
5332900e82SRobert Watsonmay be defined.
543136363fSRuslan Ermilov.Pp
5532900e82SRobert WatsonExtended attributes are named using a null-terminated character string.
5632900e82SRobert WatsonDepending on file system semantics, this name may or may not be
5732900e82SRobert Watsoncase-sensitive.  Appropriate vnode extended attribute calls are:
5832900e82SRobert Watson.Xr VOP_GETEXTATTR 9
5932900e82SRobert Watsonand
6032900e82SRobert Watson.Xr VOP_SETEXTATTR 9 .
6132900e82SRobert Watson.Sh SEE ALSO
6232900e82SRobert Watson.Xr VFS 9 ,
6332900e82SRobert Watson.Xr VOP_GETEXTATTR 9 ,
646fe89339SBen Smithurst.Xr VOP_SETEXTATTR 9
6532900e82SRobert Watson.Sh AUTHORS
6632900e82SRobert WatsonThis man page was written by
6732900e82SRobert Watson.An Robert Watson .
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