105 lines
3.2 KiB
Groff
105 lines
3.2 KiB
Groff
.\" -*- nroff -*-
|
|
.\"
|
|
.\" Copyright (c) 1996 Doug Rabson
|
|
.\"
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This program is free software.
|
|
.\"
|
|
.\" 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.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd July 24, 1996
|
|
.Os
|
|
.Dt VOP_RDWR 9
|
|
.Sh NAME
|
|
.Nm VOP_READ ,
|
|
.Nm VOP_WRITE
|
|
.Nd read or write a file
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/vnode.h
|
|
.In sys/uio.h
|
|
.Ft int
|
|
.Fn VOP_READ "struct vnode *vp" "struct uio *uio" "int ioflag" "struct ucred *cred"
|
|
.Ft int
|
|
.Fn VOP_WRITE "struct vnode *vp" "struct uio *uio" "int ioflag" "struct ucred *cred"
|
|
.Sh DESCRIPTION
|
|
These entry points read or write the contents of a file
|
|
.Pp
|
|
The arguments are:
|
|
.Bl -tag -width ioflag
|
|
.It Fa vp
|
|
The vnode of the file.
|
|
.It Fa uio
|
|
The location of the data to be read or written.
|
|
.It Fa ioflag
|
|
Various flags.
|
|
.It Fa cnp
|
|
The credentials of the caller.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fa ioflag
|
|
argument is used to give directives and hints to the file system.
|
|
When attempting a read, the high 16 bits are used to provide a
|
|
read-ahead hint (in units of file system blocks) that the file system
|
|
should attempt.
|
|
The low 16 bits are a bit mask which can contain
|
|
the following flags:
|
|
.Bl -tag -width ".Dv IO_NODELOCKED"
|
|
.It Dv IO_UNIT
|
|
Do I/O as atomic unit.
|
|
.It Dv IO_APPEND
|
|
Append write to end.
|
|
.It Dv IO_SYNC
|
|
Do I/O synchronously.
|
|
.It Dv IO_NODELOCKED
|
|
Underlying node already locked.
|
|
.It Dv IO_NDELAY
|
|
.Dv FNDELAY
|
|
flag set in file table.
|
|
.It Dv IO_VMIO
|
|
Data already in VMIO space.
|
|
.El
|
|
.Sh LOCKS
|
|
The file should be locked on entry and will still be locked on exit.
|
|
.Sh RETURN VALUES
|
|
Zero is returned on success, otherwise an error code is returned.
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er EFBIG
|
|
An attempt was made to write a file that exceeds the process's file size
|
|
limit or the maximum file size.
|
|
.It Bq Er ENOSPC
|
|
The file system is full.
|
|
.It Bq Er EPERM
|
|
An append-only flag is set on the file, but the caller is attempting to
|
|
write before the current end of file.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr uiomove 9 ,
|
|
.Xr vnode 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Doug Rabson .
|