1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1996 Doug Rabson 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd July 24, 1996 32.Os 33.Dt VOP_OPEN 9 34.Sh NAME 35.Nm VOP_OPEN , 36.Nm VOP_CLOSE 37.Nd open or close a file 38.Sh SYNOPSIS 39.In sys/param.h 40.In sys/vnode.h 41.Ft int 42.Fn VOP_OPEN "struct vnode *vp" "int mode" "struct ucred *cred" "struct thread *td" "int fdidx" 43.Ft int 44.Fn VOP_CLOSE "struct vnode *vp" "int mode" "struct ucred *cred" "struct thread *td" 45.Sh DESCRIPTION 46The 47.Fn VOP_OPEN 48entry point is called before a file is accessed by a process and the 49.Fn VOP_CLOSE 50entry point is called after a file is finished with by the process. 51.Pp 52The arguments are: 53.Bl -tag -width mode 54.It Fa vp 55the vnode of the file 56.It Fa mode 57the access mode required by the calling process 58.It Fa td 59the thread which is accessing the file 60.El 61.Pp 62Additionally, 63.Fn VOP_OPEN 64can accept a file descriptor number in 65.Fa fdidx ; 66this is useful for file systems which require such information, e.g., 67.Xr fdesc 5 . 68.Pp 69The access mode is a set of flags, including 70.Dv FREAD , 71.Dv FWRITE , 72.Dv O_NONBLOCK , 73.Dv O_APPEND . 74.Sh LOCKS 75.Fn VOP_OPEN 76expects 77.Fa vp 78to be locked on entry and will leave it locked on return. 79.Pp 80.Fn VOP_CLOSE 81expects at least a reference to be associated with the vnode and does not 82care whether the vnode is locked or not. 83The lock and reference state is left unchanged on return. 84Note that 85.Fa vn_close 86expects an unlocked, referenced vnode and will dereference the vnode prior 87to returning. 88.Sh IMPLEMENTATION NOTES 89The 90.Fa fdidx 91argument to 92.Fn VOP_OPEN 93is currently unused, use 94.Ql \-1 95for the meantime; however, this will change in future. 96.Sh RETURN VALUES 97Zero is returned on success, otherwise an error code is returned. 98.Sh PSEUDOCODE 99.Bd -literal 100int 101vop_open(struct vnode *vp, int mode, struct ucred *cred, struct thread *td) 102{ 103 /* 104 * Most file systems don't do much here. 105 */ 106 return 0; 107} 108.Ed 109.Sh SEE ALSO 110.Xr vnode 9 , 111.Xr VOP_LOOKUP 9 112.Sh AUTHORS 113This man page was written by 114.An Doug Rabson . 115