tail head cat sleep
QR code linking to this page

Manual Pages  — VOP_ATTRIB

NAME

VOP_GETATTR, VOP_SETATTR – get and set attributes on a file or directory

CONTENTS

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.

SEE ALSO

VFS(9), vnode(9), VOP_ACCESS(9)

AUTHORS

This manual page was written by Doug Rabson.

VOP_ATTRIB (9) August 8, 2020

tail head cat sleep
QR code linking to this page


Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

I'm not interested in developing a powerful brain. All I'm after is just a mediocre brain, something like the President of the American Telephone and Telegraph Company.
— Alan Turing