68 lines
2.9 KiB
Groff
68 lines
2.9 KiB
Groff
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.\"-
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.\" Copyright (c) 1999 Robert N. M. Watson
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 23, 1999
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.Os
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.Dt EXTATTR 9
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.Sh NAME
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.Nm extattr
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.Nd virtual file system named extended attributes
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.Sh SYNOPSIS
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.Fd #include <sys/param.h>
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.Fd #include <sys/vnode.h>
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.Fd #include <sys/extattr.h>
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.Sh DESCRIPTION
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Named extended attributes allow additional meta-data to be associated
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with vnodes representing files and directories. The semantics of this
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additional data is that of a "name=value" pair, where a name may
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be defined or undefined, and if defined, associated with zero or more
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bytes of arbitrary binary data. Reads of this data may return specific
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contiguous regions of the meta-data, in the style of
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.Xr VOP_READ 9 ,
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but writes will replace the entire current "value" associated with
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a given name. As there are a plethora of file systems with differing
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extended attributes, availability and functionality of these functions
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may be limited, and they should be used with awareness of the underlying
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semantics of the supporting file system. Authorization schemes for
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extended attribute data may also vary by file system, as well as
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maximum attribute size, and whether or not any or specific new attributes
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may be defined.
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Extended attributes are named using a null-terminated character string.
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Depending on file system semantics, this name may or may not be
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case-sensitive. Appropriate vnode extended attribute calls are:
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.Xr VOP_GETEXTATTR 9
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and
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.Xr VOP_SETEXTATTR 9 .
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.Sh SEE ALSO
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.Xr VFS 9 ,
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.Xr VOP_GETEXTATTR 9 ,
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.Xr VOP_SETEXTATTR 9 .
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.Sh AUTHORS
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This man page was written by
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.An Robert Watson .
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