xref: /dragonfly/share/man/man9/VOP_OPENCLOSE.9 (revision 2cd2d2b5)
1.\" Copyright (c) 1996 Doug Rabson
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30.Dd July 24, 1996
31.Os
32.Dt VOP_OPEN 9
33.Sh NAME
34.Nm VOP_OPEN ,
35.Nm VOP_CLOSE
36.Nd open or close a file
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/vnode.h
40.Ft int
41.Fn VOP_OPEN "struct vnode *vp" "int mode" "struct ucred *cred" "struct proc *p"
42.Ft int
43.Fn VOP_CLOSE "struct vnode *vp" "int mode" "struct ucred *cred" "struct proc *p"
44.Sh DESCRIPTION
45The
46.Xr VOP_OPEN 9
47entry point is called before a file is accessed by a process and the
48.Xr VOP_CLOSE 9
49entry point is called after a file is finished with by the process.
50.Pp
51The arguments are:
52.Bl -tag -width mode
53.It Ar vp
54the vnode of the file
55.It Ar mode
56the access mode required by the calling process
57.It Ar p
58the process which is accessing the file
59.El
60.Pp
61The access mode is a set of flags, including
62.Dv FREAD ,
63.Dv FWRITE ,
64.Dv O_NONBLOCK ,
65.Dv O_APPEND .
66.Sh LOCKS
67.Xr VOP_OPEN 9
68expects
69.Fa vp
70to be locked on entry and will leave it locked on return.
71.Pp
72.Xr VOP_CLOSE 9
73expects at least a reference to be associated with the vnode and does not
74care whether the vnode is locked or not.  The lock and reference state is
75left unchanged on return.  Note that
76.Fa vn_close
77expects an unlocked, referenced vnode and will dereference the vnode prior
78to returning.
79.Sh RETURN VALUES
80Zero is returned on success, otherwise an error code is returned.
81.Sh PSEUDOCODE
82.Bd -literal
83int
84vop_open(struct vnode *vp, int mode, struct ucred *cred, struct proc *p)
85{
86    /*
87     * Most filesystems don't do much here.
88     */
89    return 0;
90}
91.Ed
92.Sh SEE ALSO
93.Xr vnode 9 ,
94.Xr VOP_LOOKUP 9
95.Sh AUTHORS
96This man page was written by
97.An Doug Rabson .
98