NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | VERSIONS | CONFORMING TO | SEE ALSO | COLOPHON
LISTXATTR(2) Linux Programmer's Manual LISTXATTR(2)
listxattr, llistxattr, flistxattr - list extended attribute names
#include <sys/types.h>
#include <attr/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);
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 file system. 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 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.
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
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 file system, 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.
These system calls are Linux-specific.
getfattr(1), setfattr(1), getxattr(2), open(2), removexattr(2), setxattr(2),
stat(2), attr(5), symlink(7)
This page is part of release 3.23 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/.
Linux 2001-12-01 LISTXATTR(2)