75 lines
2.7 KiB
C
75 lines
2.7 KiB
C
/* $NetBSD: __cmsg_alignbytes.c,v 1.3 2000/04/24 10:40:24 itojun Exp $ */
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/*-
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* Copyright (c) 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jun-ichiro Hagino.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: __cmsg_alignbytes.c,v 1.3 2000/04/24 10:40:24 itojun Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#include <sys/socket.h>
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int
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__cmsg_alignbytes()
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{
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static int alignbytes = -1;
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#ifdef HW_ALIGNBYTES
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int mib[2];
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size_t len;
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int ret;
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#endif
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if (alignbytes > 0)
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return alignbytes;
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#ifdef HW_ALIGNBYTES
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mib[0] = CTL_HW;
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mib[1] = HW_ALIGNBYTES;
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len = sizeof(alignbytes);
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ret = sysctl(mib, sizeof(mib)/sizeof(mib[0]), (void *)&alignbytes,
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&len, NULL, 0);
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if (ret >= 0 && alignbytes >= 0)
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return alignbytes;
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#endif
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/* last resort */
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alignbytes = ALIGNBYTES;
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return alignbytes;
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}
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