VOP_OPEN(9)

NAME
VOP_OPEN, VOP_CLOSE - open or close a file

SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
int
VOP_OPEN(struct vnode *vp, int mode, struct ucred *cred, struct thread *td, struct file *fp);
int
VOP_CLOSE(struct vnode *vp, int mode, struct ucred *cred, struct thread *td);

DESCRIPTION
The VOP_OPEN() entry point is called before a file is accessed by a process and the VOP_CLOSE() entry point is called after a file is finished with by the process.

The arguments are:

vp  The vnode of the file.

mode
    The access mode required by the calling process.

cred
    The caller's credentials.

td  The thread which is accessing the file.

fp  The file being opened.

Pointer to the file fp is useful for file systems which require such information, e.g., fdescfs(5). Use ‘NULL’ as fp argument to VOP_OPEN() for in-kernel opens.

The access mode is a set of flags, including FREAD, FWRITE, O_NONBLOCK, O_APPEND.

The thread td passed to VOP_CLOSE() may be ‘NULL’ if the last reference to the open file is released from a kernel context, e.g., the destruction of a socket buffer containing the file reference in a SCM_RIGHTS message.

LOCKS
VOP_OPEN() expects vp to be locked on entry and will leave it locked on return.

VOP_CLOSE() expects at least a reference to be associated with the vnode and does not care whether the vnode is locked or not. The lock and reference state is left unchanged on return. Note that vn_close expects an unlocked, referenced vnode and will dereference the vnode prior to returning.

RETURN VALUES
Zero is returned on success, otherwise an error code is returned.

SEE ALSO
vnode(9), VOP_LOOKUP(9)

AUTHORS
This manual page was written by Doug Rabson.