Linux.com

listxattr.2

LISTXATTR

Section: Linux Programmer's Manual (2)
Updated: 2001-12-01
Index Return to Main Contents
 

NAME

listxattr, llistxattr, flistxattr - list extended attribute names  

SYNOPSIS

#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);
 

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 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.  

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 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.  

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), symlink(7)  

COLOPHON

This page is part of release 3.21 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
Example
RETURN VALUE
VERSIONS
CONFORMING TO
SEE ALSO
COLOPHON

 

Comments

Subscribe to Comments Feed

Upcoming Linux Foundation Courses

  1. LFD331 Developing Linux Device Drivers
    25 Aug » 29 Aug - Virtual
    Details
  2. LFD411 Embedded Linux Development
    25 Aug » 29 Aug - Santa Clara, CA
    Details
  3. LFS422 High Availability Linux Architecture
    08 Sep » 11 Sep - Raleigh, NC
    Details

View All Upcoming Courses

Become an Individual Member
Check out the Friday Funnies

Sign Up For the Linux.com Newsletter


Who we are ?

The Linux Foundation is a non-profit consortium dedicated to the growth of Linux.

More About the foundation...

Frequent Questions

Join / Linux Training / Board