xdr_sizeof.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 */
/*
 * xdr_sizeof.c
 *
 * General purpose routine to see how much space something will use
 * when serialized using XDR.
 */

#include "namespace.h"
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <sys/types.h>
#include <stdlib.h>
#include "un-namespace.h"

/* ARGSUSED */
static bool_t
x_putlong(XDR *xdrs, const long *longp)
{
	xdrs->x_handy += BYTES_PER_XDR_UNIT;
	return (TRUE);
}

/* ARGSUSED */
static bool_t
x_putbytes(XDR *xdrs, const char *bp, u_int len)
{
	xdrs->x_handy += len;
	return (TRUE);
}

static u_int
x_getpostn(XDR *xdrs)
{
	return (xdrs->x_handy);
}

/* ARGSUSED */
static bool_t
x_setpostn(XDR *xdrs, u_int pos)
{
	/* This is not allowed */
	return (FALSE);
}

static int32_t *
x_inline(XDR *xdrs, u_int len)
{
	if (len == 0) {
		return (NULL);
	}
	if (xdrs->x_op != XDR_ENCODE) {
		return (NULL);
	}
	if (len < (u_int)(uintptr_t)xdrs->x_base) {
		/* x_private was already allocated */
		xdrs->x_handy += len;
		return ((int32_t *) xdrs->x_private);
	} else {
		/* Free the earlier space and allocate new area */
		if (xdrs->x_private)
			free(xdrs->x_private);
		if ((xdrs->x_private = (caddr_t) malloc(len)) == NULL) {
			xdrs->x_base = 0;
			return (NULL);
		}
		xdrs->x_base = (caddr_t)(uintptr_t)len;
		xdrs->x_handy += len;
		return ((int32_t *) xdrs->x_private);
	}
}

static int
harmless(void)
{
	/* Always return FALSE/NULL, as the case may be */
	return (0);
}

static void
x_destroy(XDR *xdrs)
{
	xdrs->x_handy = 0;
	xdrs->x_base = 0;
	if (xdrs->x_private) {
		free(xdrs->x_private);
		xdrs->x_private = NULL;
	}
	return;
}

unsigned long
xdr_sizeof(xdrproc_t func, void *data)
{
	XDR x;
	struct xdr_ops ops;
	bool_t stat;
	/* to stop ANSI-C compiler from complaining */
	typedef  bool_t (* dummyfunc1)(XDR *, long *);
	typedef  bool_t (* dummyfunc2)(XDR *, caddr_t, u_int);

	ops.x_putlong = x_putlong;
	ops.x_putbytes = x_putbytes;
	ops.x_inline = x_inline;
	ops.x_getpostn = x_getpostn;
	ops.x_setpostn = x_setpostn;
	ops.x_destroy = x_destroy;

	/* the other harmless ones */
	ops.x_getlong =  (dummyfunc1) harmless;
	ops.x_getbytes = (dummyfunc2) harmless;

	x.x_op = XDR_ENCODE;
	x.x_ops = &ops;
	x.x_handy = 0;
	x.x_private = (caddr_t) NULL;
	x.x_base = (caddr_t) 0;

	stat = func(&x, data);
	if (x.x_private)
		free(x.x_private);
	return (stat == TRUE ? (unsigned) x.x_handy: 0);
}