Проект OpenNet: MAN VOP_OPENCLOSE (9) Ядро (FreeBSD и Linux)

Интерактивная система просмотра системных руководств (man-ов)

VOP_OPENCLOSE (9)

>> VOP_OPENCLOSE (9) ( FreeBSD man: Ядро )

BSD mandoc

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:

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 FREAD FWRITE O_NONBLOCK O_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;
}