1 /* $OpenBSD: mem2.c,v 1.5 2011/09/21 18:08:07 jsg Exp $ */
2 /* $NetBSD: mem2.c,v 1.3 1995/10/02 17:27:11 jpo Exp $ */
3
4 /*
5 * Copyright (c) 1994, 1995 Jochen Pohl
6 * All Rights Reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Jochen Pohl for
19 * The NetBSD Project.
20 * 4. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 #include <sys/param.h>
36 #include <sys/types.h>
37 #include <sys/mman.h>
38 #include <unistd.h>
39 #include <string.h>
40 #include <err.h>
41
42 #include "lint2.h"
43
44 /* length of new allocated memory blocks */
45 static size_t mblklen;
46
47 /* offset of next free byte in mbuf */
48 static size_t nxtfree;
49
50 /* current buffer to server memory requests from */
51 static void *mbuf;
52
53 void
initmem(void)54 initmem(void)
55 {
56 int pgsz;
57
58 pgsz = getpagesize();
59 mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz;
60
61 nxtfree = mblklen;
62 }
63
64 /*
65 * Allocate memory in large chunks to avoid space and time overhead of
66 * malloc(). This is possible because memory allocated by xalloc()
67 * need never to be freed.
68 */
69 void *
xalloc(size_t sz)70 xalloc(size_t sz)
71 {
72 void *ptr;
73 int prot, flags;
74
75 sz = ALIGN(sz);
76 if (nxtfree + sz > mblklen) {
77 /* use mmap() instead of malloc() to avoid malloc overhead. */
78 prot = PROT_READ | PROT_WRITE;
79 flags = MAP_ANON | MAP_PRIVATE;
80 mbuf = mmap(NULL, mblklen, prot, flags, -1, (off_t)0);
81 if (mbuf == MAP_FAILED)
82 err(1, "can't map memory");
83 if (ALIGN((u_long)mbuf) != (u_long)mbuf)
84 errx(1, "mapped address is not aligned");
85 (void)memset(mbuf, 0, mblklen);
86 nxtfree = 0;
87 }
88
89 ptr = (char *)mbuf + nxtfree;
90 nxtfree += sz;
91
92 return (ptr);
93 }
94