getxattr

GETXATTR(2)			 System calls			  GETXATTR(2)



NAME
       getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value

SYNOPSIS
       #include <sys/types.h>
       #include <attr/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 filedes, const char *name,
			    void *value, 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).

       getxattr	 retrieves  the value of the extended attribute identified by
       name and associated with the given path in the filesystem.  The length
       of the attribute value is returned.

       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 pointed to by
       filedes (as returned by open(2)) is interrogated in place of path.

       An 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.   The	value  of  an
       extended	 attribute  is a chunk of arbitrary textual or binary data of
       specified length.

       An empty buffer of size zero can be passed into these calls to  return
       the current size of the named extended attribute, which can be used to
       estimate the size of a buffer which is sufficiently large to hold  the
       value associated with the extended attribute.

       The  interface  is designed to allow guessing of initial buffer sizes,
       and to enlarge buffers when the return value indicates that the buffer
       provided was too small.

RETURN VALUE
       On  success,  a positive number is returned indicating the size of the
       extended attribute value.  On failure, -1 is returned and errno is set
       appropriately.

       If the named attribute does not exist, or the process has no access to
       this attribute, errno is set to ENOATTR.

       If the size of the value 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), setxattr(2), listxattr(2),
       removexattr(2), and attr(5).



Dec 2001		     Extended Attributes		  GETXATTR(2)