NAME | C SYNOPSIS | DESCRIPTION | DIAGNOSTICS | SEE ALSO | COLOPHON

ATTR_GET(3)                 XFS Compatibility API                ATTR_GET(3)

NAME         top

       attr_get, attr_getf - get the value of a user attribute of a filesys‐
       tem object

C SYNOPSIS         top

       #include <attr/attributes.h>

       int attr_get (const char *path, const char *attrname,
                     char *attrvalue, int *valuelength, int flags);

       int attr_getf (int fd, const char *attrname,
                      char *attrvalue, int *valuelength, int flags);

DESCRIPTION         top

       The attr_get and attr_getf functions provide a way to retrieve the
       value of an attribute.

       Path points to a path name for a filesystem object, and fd refers to
       the file descriptor associated with a file.  If the attribute
       attrname exists, the value associated with it will be copied into the
       attrvalue buffer.  The valuelength argument is an input/output
       argument that on the call to attr_get should contain the maximum size
       of attribute value the process is willing to accept.  On return, the
       valuelength will have been modified to show the actual size of the
       attribute value returned.  The flags argument can contain the
       following symbols bitwise OR'ed together:

       ATTR_ROOT
              Look for attrname in the root address space, not in the user
              address space.  (limited to use by super-user only)

       ATTR_DONTFOLLOW
              Do not follow symbolic links when resolving a path on an
              attr_get function call.  The default is to follow symbolic
              links.

       attr_get will fail if one or more of the following are true:

       [ENOATTR]        The attribute name given is not associated with the
                        indicated filesystem object.

       [E2BIG]          The value of the given attribute is too large to fit
                        into the buffer.  The integer that the valuelength
                        argument points to has been modified to show the
                        actual number of bytes that would be required to
                        store the value of that attribute.

       [ENOENT]         The named file does not exist.

       [EPERM]          The effective user ID does not match the owner of
                        the file and the effective user ID is not super-
                        user.

       [ENOTDIR]        A component of the path prefix is not a directory.

       [EACCES]         Search permission is denied on a component of the
                        path prefix.

       [EINVAL]         A bit was set in the flag argument that is not
                        defined for this system call.

       [EFAULT]         Path, attrname, attrvalue, or valuelength points
                        outside the allocated address space of the process.

       [ELOOP]          A path name lookup involved too many symbolic links.

       [ENAMETOOLONG]   The length of path exceeds {MAXPATHLEN}, or a
                        pathname component is longer than {MAXNAMELEN}.

       attr_getf will fail if:

       [ENOATTR]      The attribute name given is not associated with the
                      indicated filesystem object.

       [E2BIG]        The value of the given attribute is too large to fit
                      into the buffer.  The integer that the valuelength
                      argument points to has been modified to show the
                      actual numnber of bytes that would be required to
                      store the value of that attribute.

       [EINVAL]       A bit was set in the flag argument that is not defined
                      for this system call, or fd refers to a socket, not a
                      file.

       [EFAULT]       Attrname, attrvalue, or valuelength points outside the
                      allocated address space of the process.

       [EBADF]        Fd does not refer to a valid descriptor.

DIAGNOSTICS         top

       On success, zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

SEE ALSO         top

       attr(1), attr_list(3), attr_multi(3), attr_remove(3), and
       attr_set(3).

COLOPHON         top

       This page is part of the attr (manipulating filesystem extended
       attributes) project.  Information about the project can be found at
       ⟨http://savannah.nongnu.org/projects/attr⟩.  If you have a bug report
       for this manual page, see 
       ⟨http://savannah.nongnu.org/bugs/?group=attr⟩.  This page was obtained
       from the project's upstream Git repository 
       ⟨git://git.savannah.nongnu.org/attr.git⟩ on 2017-07-05.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

Dec 2001                     Extended Attributes                 ATTR_GET(3)

Pages that refer to this page: attr_multi(3)attr_remove(3)attr_set(3)