/share/man/man9/VOP_LISTEXTATTR.9

  1.\"-
  2.\" Copyright (c) 2003 Network Associates Technology, Inc.
  3.\" All rights reserved.
  4.\"
  5.\" This software was developed for the FreeBSD Project in part by Network
  6.\" Associates Laboratories, the Security Research Division of Network
  7.\" Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
  8.\" as part of the DARPA CHATS research program.
  9.\"
 10.\" Redistribution and use in source and binary forms, with or without
 11.\" modification, are permitted provided that the following conditions
 12.\" are met:
 13.\" 1. Redistributions of source code must retain the above copyright
 14.\"    notice, this list of conditions and the following disclaimer.
 15.\" 2. Redistributions in binary form must reproduce the above copyright
 16.\"    notice, this list of conditions and the following disclaimer in the
 17.\"    documentation and/or other materials provided with the distribution.
 18.\"
 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 22.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 29.\" SUCH DAMAGE.
 30.\"
 31.\" $FreeBSD$
 32.\"
 33.Dd August 19, 2005
 34.Dt VOP_LISTEXTATTR 9
 35.Os
 36.Sh NAME
 37.Nm VOP_LISTEXTATTR
 38.Nd retrieve a list of named extended attribute from a vnode
 39.Sh SYNOPSIS
 40.In sys/param.h
 41.In sys/vnode.h
 42.In sys/extattr.h
 43.Ft int
 44.Fo VOP_LISTEXTATTR
 45.Fa "struct vnode *vp"
 46.Fa "int attrnamespace"
 47.Fa "struct uio *uio"
 48.Fa "size_t *size"
 49.Fa "struct ucred *cred"
 50.Fa "struct thread *td"
 51.Fc
 52.Sh DESCRIPTION
 53This vnode call may be used to retrieve a list of named extended attributes
 54from a specified namespace on a file or directory.
 55.Pp
 56Its arguments are:
 57.Bl -tag -width ".Fa attrnamespace"
 58.It Fa vp
 59The vnode of the file or directory.
 60.It Fa attrnamespace
 61Integer constant indicating which extended attribute namespace the attribute
 62name is present in.
 63.It Fa uio
 64The location of the data to be read.
 65The resulting data will be a list of attribute names.
 66Each list entry consists of a single byte containing the length of
 67the attribute name, followed by the attribute name.
 68The attribute name is not terminated by
 69.Tn ASCII
 70.Dv NUL .
 71.It Fa size
 72If not
 73.Dv NULL ,
 74on return it will contain the number of bytes required to read the list.
 75In most cases
 76.Fa uio
 77will be
 78.Dv NULL
 79when
 80.Fa size
 81is not, and vice versa.
 82.It Fa cred
 83The user credentials to use in authorizing the request.
 84.It Fa td
 85The thread requesting the extended attribute.
 86.El
 87.Pp
 88The
 89.Fa cred
 90pointer may be
 91.Dv NULL
 92to indicate that access control checks are not to be performed, if possible.
 93This
 94.Fa cred
 95setting might be used to allow the kernel to authorize extended attribute
 96retrieval that the active process might not be permitted to do.
 97.Pp
 98Extended attribute semantics may vary by file system implementing the call.
 99More information on extended attributes may be found in
100.Xr extattr 9 .
101.Sh LOCKS
102The vnode will be locked on entry and should remain locked on return.
103.Sh RETURN VALUES
104On success, zero will be returned, and the
105.Fa uio
106structure will be updated to
107reflect the list read.
108Otherwise, an appropriate error code is returned.
109.Sh ERRORS
110.Bl -tag -width Er
111.It Bq Er EACCES
112The caller does not have the appropriate privilege.
113.It Bq Er ENXIO
114The request was not valid in this file system for the specified vnode and
115attribute name.
116.It Bq Er ENOMEM
117Sufficient memory is not available to fulfill the request.
118.It Bq Er EFAULT
119The
120.Fa uio
121structure refers to an invalid userspace address.
122.It Bq Er EINVAL
123The
124.Fa namespace
125or
126.Fa uio
127argument is invalid.
128.It Bq Er EOPNOTSUPP
129The file system does not support
130.Fn VOP_LISTEXTATTR .
131.El
132.Sh SEE ALSO
133.Xr extattr 9 ,
134.Xr vnode 9 ,
135.Xr VOP_GETEXTATTR 9 ,
136.Xr VOP_SETEXTATTR 9