97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
/* $NetBSD: mem2.c,v 1.2 1995/07/03 21:24:54 cgd Exp $ */
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/*
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* Copyright (c) 1994, 1995 Jochen Pohl
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* All Rights Reserved.
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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 Jochen Pohl for
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* The NetBSD Project.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef lint
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static char rcsid[] = "$NetBSD: mem2.c,v 1.2 1995/07/03 21:24:54 cgd Exp $";
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#endif
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <string.h>
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#include "lint2.h"
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/* length of new allocated memory blocks */
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static size_t mblklen;
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/* offset of next free byte in mbuf */
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static size_t nxtfree;
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/* current buffer to server memory requests from */
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static void *mbuf;
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void
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initmem()
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{
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int pgsz;
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pgsz = getpagesize();
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mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz;
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nxtfree = mblklen;
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}
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/*
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* Allocate memory in large chunks to avoid space and time overhead of
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* malloc(). This is possible because memory allocated by xalloc()
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* need never to be freed.
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*/
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void *
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xalloc(sz)
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size_t sz;
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{
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void *ptr;
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int prot, flags;
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sz = ALIGN(sz);
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if (nxtfree + sz > mblklen) {
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/* use mmap() instead of malloc() to avoid malloc overhead. */
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prot = PROT_READ | PROT_WRITE;
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flags = MAP_ANON | MAP_PRIVATE;
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mbuf = mmap(NULL, mblklen, prot, flags, -1, (off_t)0);
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if (mbuf == (void *)-1)
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err(1, "can't map memory");
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if (ALIGN((u_long)mbuf) != (u_long)mbuf)
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errx(1, "mapped address is not aligned");
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(void)memset(mbuf, 0, mblklen);
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nxtfree = 0;
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}
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ptr = (char *)mbuf + nxtfree;
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nxtfree += sz;
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return (ptr);
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}
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