EXTATTR(9) BSD Kernel Developer's Manual EXTATTR(9)NAMEextattr — virtual file system named extended attributes
SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/extattr.h>
DESCRIPTION
Named extended attributes allow additional meta-data to be associated
with vnodes representing files and directories. The semantics of this
additional data is that of a "name=value" pair, where a name may be
defined or undefined, and if defined, associated with zero or more bytes
of arbitrary binary data.
Reads of extended attribute data may return specific contiguous regions
of the meta-data, in the style of VOP_READ(9), but writes will replace
the entire current "value" associated with a given name. As there are a
plethora of file systems with differing extended attributes, availability
and functionality of these functions may be limited, and they should be
used with awareness of the underlying semantics of the supporting file
system. Authorization schemes for extended attribute data may also vary
by file system, as well as maximum attribute size, and whether or not any
or specific new attributes may be defined.
Extended attributes are named using a null-terminated character string.
Depending on underlying file system semantics, this name may or may not
be case-sensitive. Appropriate vnode extended attribute calls are:
VOP_GETEXTATTR(9) and VOP_SETEXTATTR(9).
SEE ALSOVFS(9), VOP_GETEXTATTR(9), VOP_SETEXTATTR(9)AUTHORS
This manual page was written by Robert Watson.
BSD May 8, 2010 BSD
