VOP_OPEN, VOP_CLOSE — open or close a file

       This manual page was written by Doug Rabson.

Debian                                          December 2, 2009                                     VOP_OPEN(9)

       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.

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.

       VOP_OPEN, VOP_CLOSE — open or close a file

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

vnode(9), VOP_LOOKUP(9)

#include<sys/param.h>#include<sys/vnode.h>intVOP_OPEN(structvnode*vp, intmode, structucred*cred, structthread*td, structfile*fp);

       intVOP_CLOSE(structvnode*vp, intmode, structucred*cred, structthread*td);