VOP_GETEXTATTR(9)

NAME
VOP_GETEXTATTR - retrieve named extended attribute from a vnode

SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/extattr.h>
int
VOP_GETEXTATTR(struct vnode *vp, char *name, struct uio *uio, struct ucred *cred, struct proc *p);

DESCRIPTION
This vnode call may be used to retrieve a specific named extended attribute from a file or directory.

Its arguments are:

vp  the vnode of the file or directory

name
    pointer to a null-terminated character string containing the attribute name

uio the location of the data to be read or written

cred
    the user credentials to use in authorizing the request

p   the process requesting the extended attribute

The cred pointer may be NULL to indicate that access control checks are not to be performed, if possible. This cred setting might be used to allow the kernel to authorize extended attribute retrieval that the active process might not be permitted to do.

Extended attribute semantics may vary by file system implementing the call. More information on extended attributes may be found in extattr(9).

LOCKS
No locks are required to call this vnode method, and any locks held on entry will be held on exit.

RETURN VALUES
On success, zero will be returned, and the uio structure will be updated to reflect data read. Otherwise, an appropriate error code is returned.

ERRORS

[ENOENT]
    The attribute name is not defined for this vnode

[EACCES]
    Permission denied

[ENXIO]
    The request was not valid in this file system for the specified vnode and attribute name.

[ENOMEM]
    Insufficient memory available to fulfill request

[EFAULT]
    The uio structure refers to an invalid userspace address.

[EINVAL]
    The name or uio argument is invalid.

[EOPNOTSUPP]
    The file system does not support VOP_GETEXTATTR()

SEE ALSO
extattr(9), vnode(9), VOP_SETEXTATTR(9)