This vnode call may be used to set specific named extended attribute for a
file or directory.
Its arguments are:
Fa vp
The vnode of the file or directory.
Fa attrnamespace
Integer constant indicating which extended attribute namespace the attribute
name is present in.
Fa name
Pointer to a null-terminated character string containing the attribute name.
Fa uio
The location of the data to be read or written.
Fa cred
The user credentials to use in authorizing the request.
Fa td
The thread setting the extended attribute.
The uio structure is used in a manner similar to the argument of the same
name in
VOP_WRITE9.
However, as extended attributes provide a strict "name=value" semantic,
non-zero offsets will be rejected.
The
Fa uio
pointer may be
NULL
to indicate that the specified extended attribute should be deleted.
The
Fa cred
pointer may be
NULL
to indicate that access control checks are not to be performed, if possible.
This
Fa cred
setting might be used to allow the kernel to authorize extended attribute
changes that the active process might not be permitted to make.
Extended attribute semantics may vary by file system implementing the call.
More information on extended attributes may be found in
extattr(9).
LOCKS
The vnode will be locked on entry and should remain locked on return.
RETURN VALUES
If the extended attribute is successfully set, then zero is returned.
Otherwise, an appropriate error code is returned.
ERRORS
Bq Er EACCES
The the caller does not have the appropriate privilege.
Bq Er ENXIO
The request was not valid in this file system for the specified vnode and
attribute name.
Bq Er ENOMEM
Insufficient memory available to fulfill request
Bq Er EFAULT
The uio structure refers to an invalid userspace address.
Bq Er EINVAL
The name, namespace, or uio argument is invalid.
Bq Er EOPNOTSUPP
The file system does not support
VOP_SETEXTATTR (.);
