1 /*********************************************************************
2 * RPC for the Windows NT Operating System
3 * 1993 by Martin F. Gergeleit
4 * Users may use, copy or modify Sun RPC for the Windows NT Operating
5 * System according to the Sun copyright below.
7 * RPC for the Windows NT Operating System COMES WITH ABSOLUTELY NO
8 * WARRANTY, NOR WILL I BE LIABLE FOR ANY DAMAGES INCURRED FROM THE
9 * USE OF. USE ENTIRELY AT YOUR OWN RISK!!!
10 *********************************************************************/
12 /* @(#)pmap_prot2.c 2.1 88/07/29 4.0 RPCSRC */
14 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
15 * unrestricted use provided that this legend is included on all tape
16 * media and as a part of the software program in whole or part. Users
17 * may copy or modify Sun RPC without charge, but are not authorized
18 * to license or distribute it to anyone else except as part of a product or
19 * program developed by the user.
21 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
22 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
25 * Sun RPC is provided with no support and without any obligation on the
26 * part of Sun Microsystems, Inc. to assist in its use, correction,
27 * modification or enhancement.
29 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
30 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
31 * OR ANY PART THEREOF.
33 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
34 * or profits or other special, indirect and consequential damages, even if
35 * Sun has been advised of the possibility of such damages.
37 * Sun Microsystems, Inc.
39 * Mountain View, California 94043
41 #if !defined(lint) && defined(SCCSIDS)
42 static char sccsid[] = "@(#)pmap_prot2.c 1.3 87/08/11 Copyr 1984 Sun Micro";
47 * Protocol for the local binder service, or pmap.
49 * Copyright (C) 1984, Sun Microsystems, Inc.
53 #include <rpc/types.h>
55 #include <rpc/pmap_prot.h>
58 * What is going on with linked lists? (!)
59 * First recall the link list declaration from pmap_prot.h:
62 * struct pmap pml_map;
63 * struct pmaplist *pml_map;
66 * Compare that declaration with a corresponding xdr declaration that
67 * is (a) pointer-less, and (b) recursive:
69 * typedef union switch (bool_t) {
76 * case FALSE: struct {};
79 * Notice that the xdr declaration has no nxt pointer while
80 * the C declaration has no bool_t variable. The bool_t can be
81 * interpreted as ``more data follows me''; if FALSE then nothing
82 * follows this bool_t; if TRUE then the bool_t is followed by
83 * an actual struct pmap, and then (recursively) by the
84 * xdr union, pamplist_t.
86 * This could be implemented via the xdr_union primitive, though this
87 * would cause a one recursive call per element in the list. Rather than do
88 * that we can ``unwind'' the recursion
89 * into a while loop and do the union arms in-place.
91 * The head of the list is what the C programmer wishes to past around
92 * the net, yet is the data that the pointer points to which is interesting;
93 * this sounds like a job for xdr_reference!
96 xdr_pmaplist(xdrs, rp)
98 register struct pmaplist **rp;
101 * more_elements is pre-computed in case the direction is
102 * XDR_ENCODE or XDR_FREE. more_elements is overwritten by
103 * xdr_bool when the direction is XDR_DECODE.
105 bool_t more_elements;
106 register int freeing = (xdrs->x_op == XDR_FREE);
107 register struct pmaplist **next;
110 more_elements = (bool_t)(*rp != NULL);
111 if (! xdr_bool(xdrs, &more_elements))
114 return (TRUE); /* we are done */
116 * the unfortunate side effect of non-recursion is that in
117 * the case of freeing we must remember the next object
118 * before we free the current object ...
121 next = &((*rp)->pml_next);
122 if (! xdr_reference(xdrs, (caddr_t *)rp,
123 (u_int)sizeof(struct pmaplist), xdr_pmap))
125 rp = (freeing) ? next : &((*rp)->pml_next);