.\"	$OpenBSD: fhopen.2,v 1.6 2003/03/17 09:52:21 jmc Exp $
.\"	$NetBSD: fhopen.2,v 1.2 1999/12/02 21:42:36 kleink Exp $
.\"
.\" Copyright (c) 1999 National Aeronautics & Space Administration
.\" All rights reserved.
.\"
.\" This software was written by William Studenmund of the
.\" Numerical Aerospace Similation Facility, NASA Ames Research Center.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the the name of the National Aeronautics & Space Administration
.\"    nor the names of its contributors may be used to endorse or promote
.\"    products derived from this software without specific prior written
.\"    permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
.\" UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"/
.Dd June 29, 1999
.Dt FHOPEN 2
.Os
.Sh NAME
.Nm fhopen ,
.Nm fhstat ,
.Nm fhstatfs
.Nd access file via file handle
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/stat.h>
.Ft int
.Fn fhopen "const fhandle_t *fhp" "int flags"
.Ft int
.Fn fhstat "const fhandle_t *fhp" "struct stat *sb"
.Ft int
.Fn fhstatfs "const fhandle_t *fhp" "struct statfs *buf"
.Sh DESCRIPTION
These functions provide a means to access a file given the file handle
.Fa fhp .
As this method bypasses directory access restrictions, these calls are
restricted to the superuser.
.Pp
.Fn fhopen
opens the file referenced by
.Fa fhp
for reading and/or writing as specified by the argument
.Fa flags
and returns the file descriptor to the calling process.
The
.Fa flags
are specified by
.Em or Ns 'ing
together the flags used for the
.Xr open 2
call.
All said flags are valid except for
.Dv O_CREAT .
.Pp
.Fn fhstat
and
.Fn fhstatfs
provide the functionality of the
.Xr fstat 2
and
.Xr fstatfs 2
calls except that they return information for the file referred to by
.Fa fhp
rather than an open file.
.Sh RETURN VALUES
Upon successful completion,
.Fn fhopen
returns the file descriptor for the opened file, while
.Fn fhstat
and
.Fn fhstatfs
return 0.
Otherwise, \-1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
In addition to the errors returned by
.Xr open 2 ,
.Xr fstat 2 ,
and
.Xr fstatfs 2
respectively,
.Fn fhopen ,
.Fn fhstat ,
and
.Fn fhstatfs
will return
.Bl -tag -width Er
.It Bq Er EINVAL
Calling
.Fn fhopen
with
.Dv O_CREAT
set.
.It Bq Er ESTALE
The file handle
.Fa fhp
is no longer valid.
.El
.Sh SEE ALSO
.Xr fstat 2 ,
.Xr fstatfs 2 ,
.Xr getfh 2 ,
.Xr open 2
.Sh HISTORY
The
.Fn fhopen ,
.Fn fhstat ,
and
.Fn fhstatfs
functions first appeared in
.Nx 1.5 .