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x SuSE Linux 13.1-RELEASEx
LISTXATTR(2) Linux Programmer's Manual LISTXATTR(2)
NAME
listxattr, llistxattr, flistxattr - list extended attribute names
SYNOPSIS
#include <sys/types.h>
#include <sys/xattr.h>
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 fd, char *list, size_t size);
DESCRIPTION
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).
listxattr() retrieves the list of extended attribute names associated
with the given path in the filesystem. The retrieved list is placed in
list, a caller-allocated buffer whose size (in bytes) is specified in
the argument size. 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 sym-
bolic 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 referred
to by fd (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:
user.name1\0system.name1\0user.name2\0
Filesystems like ext2, ext3 and XFS which implement POSIX ACLs using
extended attributes, might return a list like this:
system.posix_acl_access\0system.posix_acl_default\0
RETURN VALUE
On success, a nonnegative number is returned indicating the size of the
extended attribute name list. On failure, -1 is returned and errno is
set appropriately.
ERRORS
ENOTSUP
Extended attributes are not supported by the filesystem, or are
disabled.
ERANGE The size of the list buffer is too small to hold the result.
In addition, the errors documented in stat(2) can also occur.
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), setx-
attr(2), stat(2), attr(5), symlink(7)
COLOPHON
This page is part of release 3.69 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
http://www.kernel.org/doc/man-pages/.
Linux 2014-02-06 LISTXATTR(2)
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