| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | SEE ALSO | COLOPHON | The Linux Programming Interface |
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 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
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 nonnegative number is returned indicating the size of
the extended attribute name list. On failure, -1 is returned and
errno is set appropriately.
ENOTSUP
Extended attributes are not supported by the file system, 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.
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 3.51 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 2013-04-09 LISTXATTR(2)
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