1/* $NetBSD: mem2.c,v 1.6 2002/01/21 19:49:52 tv Exp $ */ 2 3/* 4 * Copyright (c) 1994, 1995 Jochen Pohl 5 * All Rights Reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Jochen Pohl for 18 * The NetBSD Project. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35#if defined(__RCSID) && !defined(lint) 36__RCSID("$NetBSD: mem2.c,v 1.6 2002/01/21 19:49:52 tv Exp $"); 37#endif 38__FBSDID("$FreeBSD$"); 39 40#include <sys/param.h> 41#include <sys/types.h> 42#include <sys/mman.h> 43#include <err.h> 44#include <unistd.h> 45#include <string.h> 46 47#include "lint2.h" 48 49/* length of new allocated memory blocks */ 50static size_t mblklen; 51 52/* offset of next free byte in mbuf */ 53static size_t nxtfree; 54 55/* current buffer to server memory requests from */ 56static void *mbuf; 57 58void 59initmem(void) 60{ 61 int pgsz; 62 63 pgsz = getpagesize(); 64 mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz; 65 66 nxtfree = mblklen; 67} 68 69/* 70 * Allocate memory in large chunks to avoid space and time overhead of 71 * malloc(). This is possible because memory allocated by xalloc() 72 * need never to be freed. 73 */ 74void * 75xalloc(size_t sz) 76{ 77 void *ptr; 78 int prot, flags; 79 80 /* Align to at least 8 bytes. */ 81 sz = (sz + 7) & ~7L; 82 if (nxtfree + sz > mblklen) { 83 /* use mmap() instead of malloc() to avoid malloc overhead. */ 84 prot = PROT_READ | PROT_WRITE; 85 flags = MAP_ANON | MAP_PRIVATE; 86 mbuf = mmap(NULL, mblklen, prot, flags, -1, (off_t)0); 87 if (mbuf == (void *)MAP_FAILED) 88 err(1, "can't map memory"); 89 (void)memset(mbuf, 0, mblklen); 90 nxtfree = 0; 91 } 92 93 ptr = (char *)mbuf + nxtfree; 94 nxtfree += sz; 95 96 return (ptr); 97} 98