usr.bin/xlint/lint2/mem2.c

   1 /*      $NetBSD: mem2.c,v 1.3 1995/10/02 17:27:11 jpo 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  * $DragonFly: src/usr.bin/xlint/lint2/mem2.c,v 1.3 2004/07/07 12:13:26 asmodai Exp $
  34  */
  35
  36 #include <sys/param.h>
  37 #include <sys/types.h>
  38 #include <sys/mman.h>
  39 #include <unistd.h>
  40 #include <string.h>
  41 #include <err.h>
  42
  43 #include "lint2.h"
  44
  45 /* length of new allocated memory blocks */
  46 static size_t   mblklen;
  47
  48 /* offset of next free byte in mbuf */
  49 static size_t   nxtfree;
  50
  51 /* current buffer to server memory requests from */
  52 static void     *mbuf;
  53
  54 void
  55 initmem(void)
  56 {
  57         int     pgsz;
  58
  59         pgsz = getpagesize();
  60         mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz;
  61
  62         nxtfree = mblklen;
  63 }
  64
  65 /*
  66  * Allocate memory in large chunks to avoid space and time overhead of
  67  * malloc(). This is possible because memory allocated by xalloc()
  68  * need never to be freed.
  69  */
  70 void *
  71 xalloc(size_t sz)
  72 {
  73         void    *ptr;
  74         int     prot, flags;
  75
  76         sz = ALIGN(sz);
  77         if (nxtfree + sz > mblklen) {
  78                 /* use mmap() instead of malloc() to avoid malloc overhead. */
  79                 prot = PROT_READ | PROT_WRITE;
  80                 flags = MAP_ANON | MAP_PRIVATE;
  81                 mbuf = mmap(NULL, mblklen, prot, flags, -1, (off_t)0);
  82                 if (mbuf == (void *)MAP_FAILED)
  83                         err(1, "can't map memory");
  84                 if (ALIGN((u_long)mbuf) != (u_long)mbuf)
  85                         errx(1, "mapped address is not aligned");
  86                 (void)memset(mbuf, 0, mblklen);
  87                 nxtfree = 0;
  88         }
  89
  90         ptr = (char *)mbuf + nxtfree;
  91         nxtfree += sz;
  92
  93         return (ptr);
  94 }