GETXATTR(2)               Linux Programmer's Manual              GETXATTR(2)

NAME         top

       getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value

SYNOPSIS         top

       #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         top

       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).

       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 referred
       to by fd (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         top

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

ERRORS         top

              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>.)

              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         top

       These system calls have been available on Linux since kernel 2.4;
       glibc support is provided since version 2.3.

CONFORMING TO         top

       These system calls are Linux-specific.

SEE ALSO         top

       getfattr(1), setfattr(1), listxattr(2), open(2), removexattr(2),
       setxattr(2), stat(2), attr(5), symlink(7)

COLOPHON         top

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Linux                            2014-04-06                      GETXATTR(2)