Originální popis anglicky:
setxattr, lsetxattr, fsetxattr - set an extended attribute value
Návod, kniha: Linux Programmer's Manual
#include <sys/types.h>
#include <attr/xattr.h>
int setxattr (const char *path, const char *name,
\ const void *value, size_t size, int flags);
int lsetxattr (const char *path, const char *name,
\ const void *value, size_t size, int flags);
int fsetxattr (int filedes, const char *name,
\ const void *value, size_t size, int flags);
Extended attributes are
name:
value pairs associated with inodes
(files, directories, symlinks, etc). They are extensions to the normal
attributes which are associated with all inodes in the system (i.e. the
stat(2) data). A complete overview of extended attributes concepts can
be found in
attr(5).
setxattr sets the
value of the extended attribute identified by
name and associated with the given
path in the filesystem. The
size of the
value must be specified.
lsetxattr is identical to
setxattr, except in the case of a
symbolic link, where the extended attribute is set on the link itself, not the
file that it refers to.
fsetxattr is identical to
setxattr, only the extended attribute is
set on the open file pointed to by
filedes (as returned by
open(2)) in place of
path.
An extended attribute name is a simple NULL-terminated string. The
name
includes a namespace prefix - there may be several, disjoint namespaces
associated with an individual inode. The
value of an extended attribute
is a chunk of arbitrary textual or binary data of specified length.
The
flags parameter can be used to refine the semantics of the operation.
XATTR_CREATE specifies a pure create, which fails if the named attribute
exists already. XATTR_REPLACE specifies a pure replace operation, which fails
if the named attribute does not already exist. By default (no flags), the
extended attribute will be created if need be, or will simply replace the
value if the attribute exists.
On success, zero is returned. On failure, -1 is returned and
errno is set
appropriately.
If XATTR_CREATE is specified, and the attribute exists already,
errno is
set to EEXIST. If XATTR_REPLACE is specified, and the attribute does not
exist,
errno is set to ENOATTR.
If there is insufficient space remaining to store the extended attribute,
errno is set to either ENOSPC, or EDQUOT if quota enforcement was the
cause.
If extended attributes are not supported by the filesystem, or are disabled,
errno is set to ENOTSUP.
The errors documented for the
stat(2) system call are also applicable
here.
Andreas Gruenbacher, <
a.gruenbacher@computer.org> and the SGI XFS
development team, <
linux-xfs@oss.sgi.com>. Please send any bug
reports or comments to these addresses.
getfattr(1),
setfattr(1),
getxattr(2),
listxattr(2),
open(2),
removexattr(2),
stat(2),
attr(5)
