1.\"- 2.\" Copyright (c) 1999, 2000, 2001 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 VOP_GETEXTATTR 9 31.Sh NAME 32.Nm VOP_GETEXTATTR 33.Nd retrieve named extended attribute from a vnode 34.Sh SYNOPSIS 35.Fd #include <sys/param.h> 36.Fd #include <sys/vnode.h> 37.Fd #include <sys/extattr.h> 38.Ft int 39.Fn VOP_GETEXTATTR "struct vnode *vp" "int attrnamespace" "const char *name" "struct uio *uio" "struct ucred *cred" "struct proc *p" 40.Sh DESCRIPTION 41This vnode call may be used to retrieve a specific named extended attribute 42from a file or directory. 43.Pp 44Its arguments are: 45.Bl -tag -width type 46.It Fa vp 47the vnode of the file or directory 48.It Ar attrnamespace 49integer constant indicating which extended attribute namespace the attribute 50name is present in 51.It Fa name 52pointer to a null-terminated character string containing the attribute name 53.It Fa uio 54the location of the data to be read or written 55.It Fa cred 56the user credentials to use in authorizing the request 57.It Fa p 58the process requesting the extended attribute 59.El 60.Pp 61The 62.Fa cred 63pointer may be 64.Dv NULL 65to indicate that access control checks are not to be performed, if possible. 66This 67.Fa cred 68setting might be used to allow the kernel to authorize extended attribute 69retrieval that the active process might not be permitted to do. 70.Pp 71Extended attribute semantics may vary by file system implementing the call. 72More information on extended attributes may be found in 73.Xr extattr 9 . 74.Sh LOCKS 75The vnode will be locked on entry and should remain locked on return. 76.Sh RETURN VALUES 77On success, zero will be returned, and the uio structure will be updated to 78reflect data read. Otherwise, an appropriate error code is returned. 79.Sh ERRORS 80.Bl -tag -width Er 81.It Bq Er ENOENT 82The attribute name is not defined for this vnode 83.It Bq Er EACCES 84Permission denied 85.It Bq Er ENXIO 86The request was not valid in this file system for the specified vnode and 87attribute name. 88.It Bq Er ENOMEM 89Insufficient memory available to fulfill request 90.It Bq Er EFAULT 91The uio structure refers to an invalid userspace address. 92.It Bq Er EINVAL 93The 94.Fa name 95or 96.Fa uio 97argument is invalid. 98.It Bq Er EOPNOTSUPP 99The file system does not support 100.Fn VOP_GETEXTATTR 101.El 102.Sh SEE ALSO 103.Xr extattr 9 , 104.Xr vnode 9 , 105.Xr VOP_SETEXTATTR 9 106