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
|
/*
* Simple program to compare two mmap'd areas.
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
* $Id: mapcmp.c,v 1.2 2004/03/05 17:35:41 corbet Exp $
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/errno.h>
#include <fcntl.h>
static char *mapdev (const char *, unsigned long, unsigned long);
#define PAGE_SIZE 4096
/*
* memcmp dev1 dev2 offset pages
*/
int main (int argc, char **argv)
{
unsigned long offset, size, i;
char *addr1, *addr2;
/*
* Sanity check.
*/
if (argc != 5)
{
fprintf (stderr, "Usage: mapcmp dev1 dev2 offset pages\n");
exit (1);
}
/*
* Map the two devices.
*/
offset = strtoul (argv[3], NULL, 16);
size = atoi (argv[4])*PAGE_SIZE;
printf ("Offset is 0x%lx\n", offset);
addr1 = mapdev (argv[1], offset, size);
addr2 = mapdev (argv[2], offset, size);
/*
* Do the comparison.
*/
printf ("Comparing...");
fflush (stdout);
for (i = 0; i < size; i++)
if (*addr1++ != *addr2++)
{
printf ("areas differ at byte %ld\n", i);
exit (0);
}
printf ("areas are identical.\n");
exit (0);
}
static char *mapdev (const char *dev, unsigned long offset,
unsigned long size)
{
char *addr;
int fd = open (dev, O_RDONLY);
if (fd < 0)
{
perror (dev);
exit (1);
}
addr = mmap (0, size, PROT_READ, MAP_PRIVATE, fd, offset);
if (addr == MAP_FAILED)
{
perror (dev);
exit (1);
}
printf ("Mapped %s (%lu @ %lx) at %p\n", dev, size, offset, addr);
return (addr);
}
|
