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
|
#include <sys/types.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <errno.h>
int
main ()
{
char *data, *data2, *data3;
int i, pagesize;
int fd;
pagesize = 65536; //getpagesize();
/*
* First, make a file with some known garbage in it.
*/
data = (char *) malloc (pagesize);
if (!data)
exit (1);
for (i = 0; i < pagesize; ++i)
*(data + i) = rand ();
umask (0);
fd = creat ("conftestmmap", 0600);
if (fd < 0)
{
printf ("creat: %d\n", errno);
exit (1);
}
if (write (fd, data, pagesize) != pagesize)
{
printf ("write: %d\n", errno);
exit (1);
}
close (fd);
/*
* Next, try to mmap the file.
*/
fd = open ("conftestmmap", O_RDWR);
if (fd < 0)
{
printf ("write: %d\n", errno);
exit (1);
}
if ((data2 = mmap (data2, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE, fd, 0L)) == MAP_FAILED)
{
printf ("mmap: %d\n", errno);
exit (1);
}
for (i = 0; i < pagesize; ++i)
if (*(data + i) != *(data2 + i))
{
printf ("check-if: %d\n", errno);
exit (1);
}
/*
* Finally, make sure that changes to the mapped area
* do not percolate back to the file as seen by read().
* (This is a bug on some variants of i386 svr4.0.)
*/
for (i = 0; i < pagesize; ++i)
*(data2 + i) = *(data2 + i) + 1;
data3 = (char *) malloc (pagesize);
if (!data3)
{
printf ("malloc2: %d\n", errno);
exit (1);
}
if (read (fd, data3, pagesize) != pagesize)
{
printf ("read: %d\n", errno);
exit (1);
}
for (i = 0; i < pagesize; ++i)
if (*(data + i) != *(data3 + i))
{
printf ("check-if2: %d\n", errno);
exit (1);
}
if (msync (data2, pagesize, MS_SYNC))
{
printf ("msync: %d\n", errno);
exit (1);
}
if (munmap (data2, pagesize))
{
printf ("munmap: %d\n", errno);
exit (1);
}
close (fd);
unlink ("conftestmmap");
exit (0);
}
|
