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
|
/* $OpenBSD: mmaptest.c,v 1.5 2006/02/15 12:09:34 mickey Exp $ */
/*
* Copyright (c) 2002 Marc Espie.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``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 OPENBSD
* PROJECT OR CONTRIBUTORS 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.
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <err.h>
#include <unistd.h>
/*
* Check for mmap/ftruncate interaction. Specifically, ftruncate on
* a short file may lose modifications made through an mmapped area.
*/
int
main(int argc, char *argv[])
{
int i;
int fd;
char area[256];
char *a2;
for (i = 0 ; i < 256; i++)
area[i] = 5;
fd = open("test.out", O_WRONLY|O_CREAT|O_TRUNC, 0600);
if (fd == -1)
err(1, "open(test.out)");
if (write(fd, area, 256) != 256)
err(1, "write");
if (close(fd))
err(1, "close");
fd = open("test.out", O_RDWR);
if (fd == -1)
err(1, "open(test.out) 2");
a2 = mmap(NULL, 256, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (!a2)
err(1, "mmap");
a2[10] = 3;
msync(a2, 256, MS_SYNC|MS_INVALIDATE);
if (ftruncate(fd, 128))
err(1, "ftruncate");
if (close(fd))
err(1, "close");
fd = open("test.out", O_RDONLY);
if (fd == -1)
err(1, "open(test.out) 3");
if (read(fd, area, 256) != 128)
err(1, "read");
if (area[10] != 3)
errx(1, "area[10] != 3");
if (close(fd))
err(1, "close");
return 0;
}
|
