listxattr

LISTXATTR(2)			 System calls			 LISTXATTR(2)



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 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	 nor-
       mal  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.

EXAMPLES
       The list of names is returned as an unordered array of NULL-terminated
       character strings (attribute names are separated by NULL	 characters),
       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 filesystem, or are
       disabled, errno is set to ENOTSUP.

       The errors documented for the stat(2) system call are also  applicable
       here.

AUTHORS
       Andreas	Gruenbacher,  <a.gruenbacher@computer.org>  and	 the  SGI XFS
       development  team,  <linux-xfs@oss.sgi.com>.   Please  send  any	  bug
       reports or comments to these addresses.

SEE ALSO
       getfattr(1),  setfattr(1), open(2), stat(2), getxattr(2), setxattr(2),
       removexattr(2), and attr(5).



Dec 2001		     Extended Attributes		 LISTXATTR(2)