1/*	$OpenBSD: xdr_reference.c,v 1.13 2022/12/27 17:10:06 jmc Exp $ */
2
3/*
4 * Copyright (c) 2010, Oracle America, Inc.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met:
9 *
10 *     * Redistributions of source code must retain the above copyright
11 *       notice, this list of conditions and the following disclaimer.
12 *     * Redistributions in binary form must reproduce the above
13 *       copyright notice, this list of conditions and the following
14 *       disclaimer in the documentation and/or other materials
15 *       provided with the distribution.
16 *     * Neither the name of the "Oracle America, Inc." nor the names of its
17 *       contributors may be used to endorse or promote products derived
18 *       from this software without specific prior written permission.
19 *
20 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
25 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34/*
35 * xdr_reference.c, Generic XDR routines implementation.
36 *
37 * These are the "non-trivial" xdr primitives used to serialize and de-serialize
38 * "pointers".  See xdr.h for more info on the interface to xdr.
39 */
40
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <rpc/types.h>
45#include <rpc/xdr.h>
46
47/*
48 * XDR an indirect pointer
49 * xdr_reference is for recursively translating a structure that is
50 * referenced by a pointer inside the structure that is currently being
51 * translated.  pp references a pointer to storage. If *pp is null
52 * the  necessary storage is allocated.
53 * size is the sizeof the referenced structure.
54 * proc is the routine to handle the referenced structure.
55 */
56bool_t
57xdr_reference(XDR *xdrs,
58    caddr_t *pp,	/* the pointer to work on */
59    u_int size,		/* size of the object pointed to */
60    xdrproc_t proc)	/* xdr routine to handle the object */
61{
62	caddr_t loc = *pp;
63	bool_t stat;
64
65	if (loc == NULL)
66		switch (xdrs->x_op) {
67		case XDR_FREE:
68			return (TRUE);
69
70		case XDR_DECODE:
71			*pp = loc = (caddr_t) calloc(size, 1);
72			if (loc == NULL)
73				return (FALSE);
74			break;
75		default:
76			break;
77	}
78
79	stat = (*proc)(xdrs, loc);
80
81	if (xdrs->x_op == XDR_FREE) {
82		mem_free(loc, size);
83		*pp = NULL;
84	}
85	return (stat);
86}
87DEF_WEAK(xdr_reference);
88
89
90/*
91 * xdr_pointer():
92 *
93 * XDR a pointer to a possibly recursive data structure. This
94 * differs with xdr_reference in that it can serialize/deserialiaze
95 * trees correctly.
96 *
97 *  What's sent is actually a union:
98 *
99 *  union object_pointer switch (boolean b) {
100 *  case TRUE: object_data data;
101 *  case FALSE: void nothing;
102 *  }
103 *
104 * > objpp: Pointer to the pointer to the object.
105 * > obj_size: size of the object.
106 * > xdr_obj: routine to XDR an object.
107 *
108 */
109bool_t
110xdr_pointer(XDR *xdrs, char **objpp, u_int obj_size, xdrproc_t xdr_obj)
111{
112
113	bool_t more_data;
114
115	more_data = (*objpp != NULL);
116	if (! xdr_bool(xdrs,&more_data)) {
117		return (FALSE);
118	}
119	if (! more_data) {
120		*objpp = NULL;
121		return (TRUE);
122	}
123	return (xdr_reference(xdrs,objpp,obj_size,xdr_obj));
124}
125DEF_WEAK(xdr_pointer);
126