setxattr, lsetxattr, fsetxattr — set an extended attribute value
#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 | fd, |
| const char * | name, | |
| const void * | value, | |
| size_t | size, | |
| int | flags); |
Extended attributes are name:value pairs associated with
inodes (files, directories, symbolic links, 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 referred to by fd (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.
These system calls have been available on Linux since kernel 2.4; glibc support is provided since version 2.3.
getfattr(1), setfattr(1), getxattr(2), listxattr(2), open(2), removexattr(2), stat(2), attr(5)
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
|
Extended attributes system calls manual pages (C) Andreas Gruenbacher, February 2001 (C) Silicon Graphics Inc, September 2001 This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. |