text: /*
   * pmap_prot2.c
   * Protocol for the local binder service, or pmap.
   *
   * Copyright (c) 2010, Oracle America, Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   *
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above
   *       copyright notice, this list of conditions and the following
   *       disclaimer in the documentation and/or other materials
   *       provided with the distribution.
   *     * Neither the name of the "Oracle America, Inc." nor the names of its
   *       contributors may be used to endorse or promote products derived
   *       from this software without specific prior written permission.
   *
   *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
   *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <rpc/pmap_prot.h>
  #include <rpc/types.h>
  #include <rpc/xdr.h>
  #include <shlib-compat.h>
  
  /*
   * What is going on with linked lists? (!)
   * First recall the link list declaration from pmap_prot.h:
   *
   * struct pmaplist {
   *      struct pmap pml_map;
   *      struct pmaplist *pml_map;
   * };
   *
   * Compare that declaration with a corresponding xdr declaration that
   * is (a) pointer-less, and (b) recursive:
   *
   * typedef union switch (bool_t) {
   *
   *      case TRUE: struct {
   *              struct pmap;
   *              pmaplist_t foo;
   *      };
   *
   *      case FALSE: struct {};
   * } pmaplist_t;
   *
   * Notice that the xdr declaration has no nxt pointer while
   * the C declaration has no bool_t variable.  The bool_t can be
   * interpreted as ``more data follows me''; if FALSE then nothing
   * follows this bool_t; if TRUE then the bool_t is followed by
   * an actual struct pmap, and then (recursively) by the
   * xdr union, pamplist_t.
   *
   * This could be implemented via the xdr_union primitive, though this
   * would cause a one recursive call per element in the list.  Rather than do
   * that we can ``unwind'' the recursion
   * into a while loop and do the union arms in-place.
   *
   * The head of the list is what the C programmer wishes to past around
   * the net, yet is the data that the pointer points to which is interesting;
   * this sounds like a job for xdr_reference!
   */
  bool_t xdr_pmaplist(XDR* xdrs, struct pmaplist** rp)
  {
      /*
       * more_elements is pre-computed in case the direction is
       * XDR_ENCODE or XDR_FREE.  more_elements is overwritten by
       * xdr_bool when the direction is XDR_DECODE.
       */
      bool_t more_elements;
      int freeing = (xdrs->x_op == XDR_FREE);
      struct pmaplist* next = NULL;
  
      while (TRUE)
      {
          more_elements = (bool_t)(*rp != NULL);
          if (!xdr_bool(xdrs, &more_elements))
              return FALSE;
          if (!more_elements)
              return TRUE; /* we are done */
          /*
           * the unfortunate side effect of non-recursion is that in
           * the case of freeing we must remember the next object
           * before we free the current object ...
           */
          if (freeing)
              next = (*rp)->pml_next;
          if (!xdr_reference(xdrs, (caddr_t*)rp, (u_int)sizeof(struct pmaplist),
                             (xdrproc_t)xdr_pmap))
              return FALSE;
          rp = freeing ? &next : &((*rp)->pml_next);
      }
  }
  libc_hidden_nolink_sunrpc(xdr_pmaplist, GLIBC_2_0)
  