1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/* $OpenBSD: mem2.c,v 1.4 2005/11/20 17:09:55 cloder Exp $ */
/* $NetBSD: mem2.c,v 1.3 1995/10/02 17:27:11 jpo Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
* All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Jochen Pohl for
* The NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef lint
static char rcsid[] = "$OpenBSD: mem2.c,v 1.4 2005/11/20 17:09:55 cloder Exp $";
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <string.h>
#include <err.h>
#include "lint2.h"
/* length of new allocated memory blocks */
static size_t mblklen;
/* offset of next free byte in mbuf */
static size_t nxtfree;
/* current buffer to server memory requests from */
static void *mbuf;
void
initmem(void)
{
int pgsz;
pgsz = getpagesize();
mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz;
nxtfree = mblklen;
}
/*
* Allocate memory in large chunks to avoid space and time overhead of
* malloc(). This is possible because memory allocated by xalloc()
* need never to be freed.
*/
void *
xalloc(size_t sz)
{
void *ptr;
int prot, flags;
sz = ALIGN(sz);
if (nxtfree + sz > mblklen) {
/* use mmap() instead of malloc() to avoid malloc overhead. */
prot = PROT_READ | PROT_WRITE;
flags = MAP_ANON | MAP_PRIVATE;
mbuf = mmap(NULL, mblklen, prot, flags, -1, (off_t)0);
if (mbuf == MAP_FAILED)
err(1, "can't map memory");
if (ALIGN((u_long)mbuf) != (u_long)mbuf)
errx(1, "mapped address is not aligned");
(void)memset(mbuf, 0, mblklen);
nxtfree = 0;
}
ptr = (char *)mbuf + nxtfree;
nxtfree += sz;
return (ptr);
}
|
