NAME

       attr_get, attr_getf - get the value of a user attribute of a filesystem object

C SYNOPSIS

       #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

       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 number 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

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

SEE ALSO

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