illumos gate

The chown(2) man page contains this:

       The fchownat() function sets the owner ID and group ID of the named
       file in the same manner as chown(). If, however, the path argument is
       relative, the path is resolved relative to the fildes argument rather
       than the current working directory.  If the fildes argument has the
       special value AT_FDCWD, the path resolution reverts back to current
       working directory relative.  If the flag argument is set to SYMLNK, the
       function behaves like lchown() with respect to symbolic links. If the
       path argument is absolute, the fildes argument is ignored.  If the path
       argument is a null pointer, the function behaves like fchown().

But, apparently, SYMLNK is wrong. There is no such constant defined. It should be changed to AT_SYMLINK_NOFOLLOW. See also https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchownat.html