1*f14fb602SLionel Sambuc /* $NetBSD: __cmsg_alignbytes.c,v 1.1 2012/01/20 14:08:05 joerg Exp $ */
2*f14fb602SLionel Sambuc
3*f14fb602SLionel Sambuc /*-
4*f14fb602SLionel Sambuc * Copyright (c) 2000 The NetBSD Foundation, Inc.
5*f14fb602SLionel Sambuc * All rights reserved.
6*f14fb602SLionel Sambuc *
7*f14fb602SLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation
8*f14fb602SLionel Sambuc * by Jun-ichiro Hagino.
9*f14fb602SLionel Sambuc *
10*f14fb602SLionel Sambuc * Redistribution and use in source and binary forms, with or without
11*f14fb602SLionel Sambuc * modification, are permitted provided that the following conditions
12*f14fb602SLionel Sambuc * are met:
13*f14fb602SLionel Sambuc * 1. Redistributions of source code must retain the above copyright
14*f14fb602SLionel Sambuc * notice, this list of conditions and the following disclaimer.
15*f14fb602SLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright
16*f14fb602SLionel Sambuc * notice, this list of conditions and the following disclaimer in the
17*f14fb602SLionel Sambuc * documentation and/or other materials provided with the distribution.
18*f14fb602SLionel Sambuc *
19*f14fb602SLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*f14fb602SLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*f14fb602SLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*f14fb602SLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*f14fb602SLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*f14fb602SLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*f14fb602SLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*f14fb602SLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*f14fb602SLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*f14fb602SLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*f14fb602SLionel Sambuc * POSSIBILITY OF SUCH DAMAGE.
30*f14fb602SLionel Sambuc */
31*f14fb602SLionel Sambuc
32*f14fb602SLionel Sambuc #include <sys/cdefs.h>
33*f14fb602SLionel Sambuc __RCSID("$NetBSD: __cmsg_alignbytes.c,v 1.1 2012/01/20 14:08:05 joerg Exp $");
34*f14fb602SLionel Sambuc
35*f14fb602SLionel Sambuc #include "namespace.h"
36*f14fb602SLionel Sambuc #include <sys/types.h>
37*f14fb602SLionel Sambuc #include <sys/param.h>
38*f14fb602SLionel Sambuc #include <sys/sysctl.h>
39*f14fb602SLionel Sambuc #include <sys/socket.h>
40*f14fb602SLionel Sambuc
41*f14fb602SLionel Sambuc int __cmsg_alignbytes(void);
42*f14fb602SLionel Sambuc
43*f14fb602SLionel Sambuc int
__cmsg_alignbytes(void)44*f14fb602SLionel Sambuc __cmsg_alignbytes(void)
45*f14fb602SLionel Sambuc {
46*f14fb602SLionel Sambuc static int alignbytes = -1;
47*f14fb602SLionel Sambuc #ifdef HW_ALIGNBYTES
48*f14fb602SLionel Sambuc int mib[2];
49*f14fb602SLionel Sambuc size_t len;
50*f14fb602SLionel Sambuc int ret;
51*f14fb602SLionel Sambuc #endif
52*f14fb602SLionel Sambuc
53*f14fb602SLionel Sambuc if (alignbytes > 0)
54*f14fb602SLionel Sambuc return alignbytes;
55*f14fb602SLionel Sambuc
56*f14fb602SLionel Sambuc #ifdef HW_ALIGNBYTES
57*f14fb602SLionel Sambuc mib[0] = CTL_HW;
58*f14fb602SLionel Sambuc mib[1] = HW_ALIGNBYTES;
59*f14fb602SLionel Sambuc len = sizeof(alignbytes);
60*f14fb602SLionel Sambuc ret = sysctl(mib, (u_int) (sizeof(mib) / sizeof(mib[0])),
61*f14fb602SLionel Sambuc (void *)&alignbytes, &len, NULL, (size_t)0);
62*f14fb602SLionel Sambuc if (ret >= 0 && alignbytes >= 0)
63*f14fb602SLionel Sambuc return alignbytes;
64*f14fb602SLionel Sambuc #endif
65*f14fb602SLionel Sambuc /* last resort */
66*f14fb602SLionel Sambuc alignbytes = ALIGNBYTES;
67*f14fb602SLionel Sambuc return alignbytes;
68*f14fb602SLionel Sambuc }
69