153 lines
4 KiB
Groff
153 lines
4 KiB
Groff
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.\" $NetBSD: fhopen.2,v 1.17 2009/08/05 23:15:52 wiz Exp $
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.\"
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.\" Copyright (c) 1999 National Aeronautics & Space Administration
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.\" All rights reserved.
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.\"
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.\" This software was written by William Studenmund of the
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.\" Numerical Aerospace Simulation Facility, NASA Ames Research Center.
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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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.\" 3. Neither the name of the National Aeronautics & Space Administration
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.\" nor the names of its contributors may be used to endorse or promote
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.\" products derived from this software without specific prior written
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.\" permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
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.\" UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"/
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.Dd August 5, 2009
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.Dt FHOPEN 2
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.Os
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.Sh NAME
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.Nm fhopen ,
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.Nm fhstat ,
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.Nm fhstatvfs
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.Nd access file via file handle
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/mount.h
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.Ft int
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.Fn fhopen "const void *fhp" "size_t fh_size" "int flags"
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.In sys/stat.h
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.Ft int
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.Fn fhstat "const void *fhp" "size_t fh_size" "struct stat *sb"
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.In sys/statvfs.h
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.Ft int
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.Fn fhstatvfs "const void *fhp" "size_t fh_size" "struct statvfs *buf"
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.Ft int
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.Fn fhstatvfs1 "const void *fhp" "size_t fh_size" "struct statvfs *buf" "int flags"
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.Sh DESCRIPTION
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These functions provide a means to access a file given the opaque file handle
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.Fa fhp
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and the size
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.Fa fh_size
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of the opaque object as returned by
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.Xr getfh 2 .
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As this method bypasses directory access restrictions, these calls are
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restricted to the superuser.
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.Pp
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.Fn fhopen
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opens the file referenced by
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.Fa fhp
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for reading and/or writing as specified by the argument
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.Fa flags
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and returns the file descriptor to the calling process.
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The
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.Fa flags
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are specified by
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.Em or Ns 'ing
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together the flags used for the
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.Xr open 2
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call.
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All said flags are valid except for
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.Dv O_CREAT .
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.Pp
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.Fn fhstat ,
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.Fn fhstatvfs ,
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and
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.Fn fhstatvfs1
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provide the functionality of the
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.Xr fstat 2 ,
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.Xr fstatvfs 2 ,
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and
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.Xr fstatvfs1 2
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calls except that they return information for the file referred to by
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.Fa fhp
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rather than an open file.
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.Sh RETURN VALUES
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Upon successful completion,
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.Fn fhopen
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returns the file descriptor for the opened file, while
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.Fn fhstat ,
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.Fn fhstatvfs ,
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and
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.Fn fhstatvfs1
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return 0.
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Otherwise, \-1 is returned and
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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In addition to the errors returned by
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.Xr open 2 ,
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.Xr fstat 2 ,
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.Xr fstatvfs 2 ,
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and
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.Xr fstatvfs1 2 ,
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respectively,
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.Fn fhopen ,
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.Fn fhstat ,
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.Fn fhstatvfs ,
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and
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.Fn fhstatvfs1
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will return
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Calling
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.Fn fhopen
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with
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.Dv O_CREAT
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set or invalid
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.Fa fh_size .
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.It Bq Er ESTALE
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The file handle
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.Fa fhp
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is no longer valid.
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.El
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.Sh SEE ALSO
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.Xr fstat 2 ,
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.Xr fstatvfs 2 ,
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.Xr fstatvfs1 2 ,
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.Xr getfh 2 ,
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.Xr open 2
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.Sh HISTORY
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The
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.Fn fhopen ,
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and
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.Fn fhstat
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functions first appeared in
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.Nx 1.5 .
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The
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.Fn fhstatvfs
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function replaced
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.Fn fhstatfs
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in
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.Nx 3.0 .
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