NAME

VOP_GETATTR, VOP_SETATTR —

get and set attributes on a file or directory

SYNOPSIS

#include <sys/param.h>
#include <sys/vnode.h>

int
VOP_GETATTR(struct vnode *vp, struct vattr *vap, struct ucred *cred);

int
VOP_SETATTR(struct vnode *vp, struct vattr *vap, struct ucred *cred);

int
VOP_STAT(struct vnode *vp, struct stat *sb, struct ucred *active_cred, struct ucred *file_cred, struct thread *td);

DESCRIPTION

These entry points manipulate various attributes of a file or directory, including file permissions, owner, group, size, access time and modification time.

VOP_STAT() returns data in a format suitable for the stat(2) system call and by default is implemented as a wrapper around VOP_GETATTR(). Filesystems may want to implement their own variant for performance reasons.

For VOP_GETATTR() and VOP_SETATTR() the arguments are:

vp: The vnode of the file.
vap: The attributes of the file.
cred: The user credentials of the calling thread.

For VOP_STAT() the arguments are:

vp: The vnode of the file.
sb: The attributes of the file.
active_cred: The user credentials of the calling thread.
file_cred: The credentials installed on the file description pointing to the vnode or NOCRED.
td: The calling thread.

Attributes which are not being modified by VOP_SETATTR() should be set to the value VNOVAL; VATTR_NULL() may be used to clear all the values, and should generally be used to reset the contents of *vap prior to setting specific values.

LOCKS

Both VOP_GETATTR() and VOP_STAT() expect the vnode to be locked on entry and will leave the vnode locked on return. The lock type can be either shared or exclusive.

VOP_SETATTR() expects the vnode to be locked on entry and will leave the vnode locked on return. The lock type must be exclusive.

RETURN VALUES

VOP_GETATTR() returns 0 if it was able to retrieve the attribute data via *vap, otherwise an appropriate error is returned. VOP_SETATTR() returns zero if the attributes were changed successfully, otherwise an appropriate error is returned. VOP_STAT() returns 0 if it was able to retrieve the attribute data *sb, otherwise an appropriate error is returned.

ERRORS

[EPERM]: The file is immutable.
[EACCES]: The caller does not have permission to modify the file or directory attributes.
[EROFS]: The file system is read-only.

AUTHORS

This manual page was written by Doug Rabson.