xref: /freebsd/lib/libc/xdr/xdr_sizeof.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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  * xdr_sizeof.c
35  *
36  * General purpose routine to see how much space something will use
37  * when serialized using XDR.
38  */
39 
40 #include "namespace.h"
41 #include <rpc/types.h>
42 #include <rpc/xdr.h>
43 #include <sys/types.h>
44 #include <stdlib.h>
45 #include "un-namespace.h"
46 
47 /* ARGSUSED */
48 static bool_t
49 x_putlong(XDR *xdrs, const long *longp)
50 {
51 	xdrs->x_handy += BYTES_PER_XDR_UNIT;
52 	return (TRUE);
53 }
54 
55 /* ARGSUSED */
56 static bool_t
57 x_putbytes(XDR *xdrs, const char *bp, u_int len)
58 {
59 	xdrs->x_handy += len;
60 	return (TRUE);
61 }
62 
63 static u_int
64 x_getpostn(XDR *xdrs)
65 {
66 	return (xdrs->x_handy);
67 }
68 
69 /* ARGSUSED */
70 static bool_t
71 x_setpostn(XDR *xdrs, u_int pos)
72 {
73 	/* This is not allowed */
74 	return (FALSE);
75 }
76 
77 static int32_t *
78 x_inline(XDR *xdrs, u_int len)
79 {
80 	if (len == 0) {
81 		return (NULL);
82 	}
83 	if (xdrs->x_op != XDR_ENCODE) {
84 		return (NULL);
85 	}
86 	if (len < (u_int)(uintptr_t)xdrs->x_base) {
87 		/* x_private was already allocated */
88 		xdrs->x_handy += len;
89 		return ((int32_t *) xdrs->x_private);
90 	} else {
91 		/* Free the earlier space and allocate new area */
92 		if (xdrs->x_private)
93 			free(xdrs->x_private);
94 		if ((xdrs->x_private = (caddr_t) malloc(len)) == NULL) {
95 			xdrs->x_base = 0;
96 			return (NULL);
97 		}
98 		xdrs->x_base = (caddr_t)(uintptr_t)len;
99 		xdrs->x_handy += len;
100 		return ((int32_t *) xdrs->x_private);
101 	}
102 }
103 
104 static int
105 harmless(void)
106 {
107 	/* Always return FALSE/NULL, as the case may be */
108 	return (0);
109 }
110 
111 static void
112 x_destroy(XDR *xdrs)
113 {
114 	xdrs->x_handy = 0;
115 	xdrs->x_base = 0;
116 	if (xdrs->x_private) {
117 		free(xdrs->x_private);
118 		xdrs->x_private = NULL;
119 	}
120 	return;
121 }
122 
123 unsigned long
124 xdr_sizeof(xdrproc_t func, void *data)
125 {
126 	XDR x;
127 	struct xdr_ops ops;
128 	bool_t stat;
129 	/* to stop ANSI-C compiler from complaining */
130 	typedef  bool_t (* dummyfunc1)(XDR *, long *);
131 	typedef  bool_t (* dummyfunc2)(XDR *, caddr_t, u_int);
132 
133 	ops.x_putlong = x_putlong;
134 	ops.x_putbytes = x_putbytes;
135 	ops.x_inline = x_inline;
136 	ops.x_getpostn = x_getpostn;
137 	ops.x_setpostn = x_setpostn;
138 	ops.x_destroy = x_destroy;
139 
140 	/* the other harmless ones */
141 	ops.x_getlong =  (dummyfunc1) harmless;
142 	ops.x_getbytes = (dummyfunc2) harmless;
143 
144 	x.x_op = XDR_ENCODE;
145 	x.x_ops = &ops;
146 	x.x_handy = 0;
147 	x.x_private = (caddr_t) NULL;
148 	x.x_base = (caddr_t) 0;
149 
150 	stat = func(&x, data);
151 	if (x.x_private)
152 		free(x.x_private);
153 	return (stat == TRUE ? (unsigned) x.x_handy: 0);
154 }
155