Name
listxattr, llistxattr, flistxattr — list extended
attribute names
Synopsis
ssize_t listxattr( |
const char * |
path, |
| |
char * |
list, |
| |
size_t |
size); |
ssize_t llistxattr( |
const char * |
path, |
| |
char * |
list, |
| |
size_t |
size); |
ssize_t flistxattr( |
int |
filedes, |
| |
char * |
list, |
| |
size_t |
size); |
DESCRIPTION
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).
listxattr() retrieves the
list of extended
attribute names associated with the given path in the filesystem. The
list is the set of (null-terminated) names, one after the
other. Names of extended attributes to which the calling
process does not have access may be omitted from the list.
The length of the attribute name list is returned.
llistxattr() is identical to
listxattr(), except in the case
of a symbolic link, where the list of names of extended
attributes associated with the link itself is retrieved, not
the file that it refers to.
flistxattr() is identical to
listxattr(), only the open file
pointed to by filedes
(as returned by open(2)) is interrogated in
place of path.
A single 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.
An empty buffer of size zero can be passed into
these calls to return the current size of the list of
extended attribute names, which can be used to estimate the
size of a buffer which is sufficiently large to hold the list
of names.
Example
The list of
names is returned as an unordered array of null-terminated
character strings (attribute names are separated by null
bytes ('\0')), like this:
Filesystems like ext2, ext3 and XFS which implement
POSIX ACLs using extended attributes, might return a
list like this:
RETURN VALUE
On success, a positive number is returned indicating the
size of the extended attribute name list. On failure,
−1 is returned and errno
is set appropriately.
If the size of the
list buffer is too
small to hold the result, errno
is set to ERANGE.
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.
VERSIONS
These system calls have been available on Linux since
kernel 2.4; glibc support is provided since version 2.3.
CONFORMING TO
These system calls are Linux specific.
SEE ALSO
getfattr(1), setfattr(1), getxattr(2), open(2), removexattr(2), setxattr(2), stat(2), attr(5)
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"
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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.
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