src/lib/libc/rpc/xdr_stdio.c

/*	$OpenBSD: xdr_stdio.c,v 1.17 2022/05/14 05:06:32 guenther Exp $ */

/*
 * 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_stdio.c, XDR implementation on standard i/o file.
 *
 * This set of routines implements a XDR on a stdio stream.
 * XDR_ENCODE serializes onto the stream, XDR_DECODE de-serializes
 * from the stream.
 */

#include <stdio.h>
#include <rpc/types.h>
#include <rpc/xdr.h>

static bool_t	xdrstdio_getlong(XDR *, long *);
static bool_t	xdrstdio_putlong(XDR *, long *);
static bool_t	xdrstdio_getbytes(XDR *, caddr_t, u_int);
static bool_t	xdrstdio_putbytes(XDR *, caddr_t, u_int);
static u_int	xdrstdio_getpos(XDR *);
static bool_t	xdrstdio_setpos(XDR *, u_int);
static int32_t *xdrstdio_inline(XDR *, u_int);
static void	xdrstdio_destroy(XDR *);

/*
 * Ops vector for stdio type XDR
 */
static const struct xdr_ops	xdrstdio_ops = {
	xdrstdio_getlong,	/* deserialize a long int */
	xdrstdio_putlong,	/* serialize a long int */
	xdrstdio_getbytes,	/* deserialize counted bytes */
	xdrstdio_putbytes,	/* serialize counted bytes */
	xdrstdio_getpos,	/* get offset in the stream */
	xdrstdio_setpos,	/* set offset in the stream */
	xdrstdio_inline,	/* prime stream for inline macros */
	xdrstdio_destroy,	/* destroy stream */
	NULL,			/* xdrstdio_control */
};

/*
 * Initialize a stdio xdr stream.
 * Sets the xdr stream handle xdrs for use on the stream file.
 * Operation flag is set to op.
 */
void
xdrstdio_create(XDR *xdrs, FILE *file, enum xdr_op op)
{

	xdrs->x_op = op;
	xdrs->x_ops = &xdrstdio_ops;
	xdrs->x_private = (caddr_t)file;
	xdrs->x_handy = 0;
	xdrs->x_base = 0;
}

/*
 * Destroy a stdio xdr stream.
 * Cleans up the xdr stream handle xdrs previously set up by xdrstdio_create.
 */
static void
xdrstdio_destroy(XDR *xdrs)
{
	(void)fflush((FILE *)xdrs->x_private);
	/* xx should we close the file ?? */
}

static bool_t
xdrstdio_getlong(XDR *xdrs, long int *lp)
{
	u_int32_t temp;

	if (fread(&temp, sizeof(int32_t), 1, (FILE *)xdrs->x_private) != 1)
		return (FALSE);
	*lp = (long)ntohl(temp);
	return (TRUE);
}

static bool_t
xdrstdio_putlong(XDR *xdrs, long int *lp)
{
	int32_t mycopy = htonl((u_int32_t)*lp);

	if (fwrite(&mycopy, sizeof(int32_t), 1, (FILE *)xdrs->x_private) != 1)
		return (FALSE);
	return (TRUE);
}

static bool_t
xdrstdio_getbytes(XDR *xdrs, caddr_t addr, u_int len)
{

	if ((len != 0) && (fread(addr, (int)len, 1, (FILE *)xdrs->x_private) != 1))
		return (FALSE);
	return (TRUE);
}

static bool_t
xdrstdio_putbytes(XDR *xdrs, caddr_t addr, u_int len)
{

	if ((len != 0) && (fwrite(addr, (int)len, 1, (FILE *)xdrs->x_private) != 1))
		return (FALSE);
	return (TRUE);
}

static u_int
xdrstdio_getpos(XDR *xdrs)
{

	return ((u_int) ftell((FILE *)xdrs->x_private));
}

static bool_t
xdrstdio_setpos(XDR *xdrs, u_int pos)
{

	return ((fseeko((FILE *)xdrs->x_private, pos, SEEK_SET) == -1) ?
		FALSE : TRUE);
}

static int32_t *
xdrstdio_inline(XDR *xdrs, u_int len)
{

	/*
	 * Must do some work to implement this: must ensure
	 * enough data in the underlying stdio buffer,
	 * that the buffer is aligned so that we can indirect through a
	 * long *, and stuff this pointer in xdrs->x_buf.  Doing
	 * a fread or fwrite to a scratch buffer would defeat
	 * most of the gains to be had here and require storage
	 * management on this buffer, so we don't do this.
	 */
	return (NULL);
}