Name

getxattr, lgetxattr, fgetxattr — retrieve an extended attribute value

Synopsis

#include <sys/types.h>
#include <sys/xattr.h>
ssize_t getxattr( const char *path,
  const char *name,
  void *value,
  size_t size);
 
ssize_t lgetxattr( const char *path,
  const char *name,
  void *value,
  size_t size);
 
ssize_t fgetxattr( int fd,
  const char *name,
  void *value,
  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 xattr(7).

getxattr() retrieves the value of the extended attribute identified by name and associated with the given path in the filesystem. The attribute value is placed in the buffer pointed to by value; size specifies the size of that buffer. The return value of the call is the number of bytes placed in value.

lgetxattr() is identical to getxattr(), except in the case of a symbolic link, where the link itself is interrogated, not the file that it refers to.

fgetxattr() is identical to getxattr(), only the open file referred to by fd (as returned by open(2)) is interrogated in place of path.

An extended attribute name is a null-terminated string. The name includes a namespace prefix; there may be several, disjoint namespaces associated with an individual inode. The value of an extended attribute is a chunk of arbitrary textual or binary data that was assigned using setxattr(2).

If size is specified as zero, these calls return the current size of the named extended attribute (and leave value unchanged). This can be used to determine the size of the buffer that should be supplied in a subsequent call. (But, bear in mind that there is a possibility that the attribute value may change between the two calls, so that it is still necessary to check the return status from the second call.)

RETURN VALUE

On success, these calls return a nonnegative value which is the size (in bytes) of the extended attribute value. On failure, −1 is returned and errno is set appropriately.

ERRORS

ENOATTR

The named attribute does not exist, or the process has no access to this attribute. (ENOATTR is defined to be a synonym for ENODATA in <attr/xattr.h>

ENOTSUP

Extended attributes are not supported by the filesystem, or are disabled.

ERANGE

The size of the value 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.

EXAMPLE

See listxattr(2).

SEE ALSO

getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2), setxattr(2), stat(2), symlink(7), xattr(7)

COLOPHON

This page is part of release 4.07 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 https://www.kernel.org/doc/man−pages/.


  Copyright (C) Andreas Gruenbacher, February 2001
Copyright (C) Silicon Graphics Inc, September 2001

%%%LICENSE_START(GPLv2+_DOC_FULL)
This is free documentation; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.

The GNU General Public License's references to "object code"
and "executables" are to be interpreted as the output of any
document formatting or typesetting system, including
intermediate and printed output.

This manual is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public
License along with this manual; if not, see
<http://www.gnu.org/licenses/>.
%%%LICENSE_END