xref: /freebsd/lib/libc/xdr/xdr_sizeof.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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 <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "namespace.h"
44 #include <rpc/types.h>
45 #include <rpc/xdr.h>
46 #include <sys/types.h>
47 #include <stdlib.h>
48 #include "un-namespace.h"
49 
50 /* ARGSUSED */
51 static bool_t
52 x_putlong(XDR *xdrs, const long *longp)
53 {
54 	xdrs->x_handy += BYTES_PER_XDR_UNIT;
55 	return (TRUE);
56 }
57 
58 /* ARGSUSED */
59 static bool_t
60 x_putbytes(XDR *xdrs, const char *bp, u_int len)
61 {
62 	xdrs->x_handy += len;
63 	return (TRUE);
64 }
65 
66 static u_int
67 x_getpostn(XDR *xdrs)
68 {
69 	return (xdrs->x_handy);
70 }
71 
72 /* ARGSUSED */
73 static bool_t
74 x_setpostn(XDR *xdrs, u_int pos)
75 {
76 	/* This is not allowed */
77 	return (FALSE);
78 }
79 
80 static int32_t *
81 x_inline(XDR *xdrs, u_int len)
82 {
83 	if (len == 0) {
84 		return (NULL);
85 	}
86 	if (xdrs->x_op != XDR_ENCODE) {
87 		return (NULL);
88 	}
89 	if (len < (u_int)(uintptr_t)xdrs->x_base) {
90 		/* x_private was already allocated */
91 		xdrs->x_handy += len;
92 		return ((int32_t *) xdrs->x_private);
93 	} else {
94 		/* Free the earlier space and allocate new area */
95 		if (xdrs->x_private)
96 			free(xdrs->x_private);
97 		if ((xdrs->x_private = (caddr_t) malloc(len)) == NULL) {
98 			xdrs->x_base = 0;
99 			return (NULL);
100 		}
101 		xdrs->x_base = (caddr_t)(uintptr_t)len;
102 		xdrs->x_handy += len;
103 		return ((int32_t *) xdrs->x_private);
104 	}
105 }
106 
107 static int
108 harmless(void)
109 {
110 	/* Always return FALSE/NULL, as the case may be */
111 	return (0);
112 }
113 
114 static void
115 x_destroy(XDR *xdrs)
116 {
117 	xdrs->x_handy = 0;
118 	xdrs->x_base = 0;
119 	if (xdrs->x_private) {
120 		free(xdrs->x_private);
121 		xdrs->x_private = NULL;
122 	}
123 	return;
124 }
125 
126 unsigned long
127 xdr_sizeof(xdrproc_t func, void *data)
128 {
129 	XDR x;
130 	struct xdr_ops ops;
131 	bool_t stat;
132 	/* to stop ANSI-C compiler from complaining */
133 	typedef  bool_t (* dummyfunc1)(XDR *, long *);
134 	typedef  bool_t (* dummyfunc2)(XDR *, caddr_t, u_int);
135 
136 	ops.x_putlong = x_putlong;
137 	ops.x_putbytes = x_putbytes;
138 	ops.x_inline = x_inline;
139 	ops.x_getpostn = x_getpostn;
140 	ops.x_setpostn = x_setpostn;
141 	ops.x_destroy = x_destroy;
142 
143 	/* the other harmless ones */
144 	ops.x_getlong =  (dummyfunc1) harmless;
145 	ops.x_getbytes = (dummyfunc2) harmless;
146 
147 	x.x_op = XDR_ENCODE;
148 	x.x_ops = &ops;
149 	x.x_handy = 0;
150 	x.x_private = (caddr_t) NULL;
151 	x.x_base = (caddr_t) 0;
152 
153 	stat = func(&x, data);
154 	if (x.x_private)
155 		free(x.x_private);
156 	return (stat == TRUE ? (unsigned) x.x_handy: 0);
157 }
158