#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:
Fa vp
The vnode of the file.
Fa mode
The access mode required by the calling process.
Fa td
The thread which is accessing the file.
Fa fp
The file being opened.
Pointer to the file
Fa fp
is useful for file systems which require such information, e.g.,
fdescfs(5).
Use
`NULL'
as
Fa fp
argument to
VOP_OPEN ();
for in-kernel opens.
The access mode is a set of flags, including
FREADFWRITEO_NONBLOCKO_APPEND
LOCKS
VOP_OPEN ();
expects
Fa 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
Fa 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.
PSEUDOCODE
int
vop_open(struct vnode *vp, int mode, struct ucred *cred, struct thread *td,
struct file *fp)
{
/*
* Most file systems don't do much here.
*/
return 0;
}