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
|
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2010 Intel Corporation
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <sys/mman.h>
#include <signal.h>
#include <sys/stat.h>
int main(int argc, char *argv[])
{
int ret;
char *cc = "01234";
char *progname;
loff_t size;
loff_t amount = 1;
loff_t from = 2;
loff_t to = 3;
int fd;
void *mapped_mem;
progname = argv[0];
size = 5;
fd = open(argv[1], O_RDWR|O_TRUNC|O_CREAT, 0666);
if (fd < 0) {
fprintf(stderr, "%s: Cannot open `%s': %s\n",
progname, argv[1], strerror(errno));
exit(1);
}
if ((ret = pwrite(fd, (const char *)cc,
size, 0)) != size) {
perror("pwrite");
exit(1);
}
mapped_mem = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (mapped_mem == MAP_FAILED) {
perror("mmap");
exit(1);
}
printf("pwrite %Ld bytes from %Ld to %Ld\n",
(long long) amount, (long long) from, (long long) to);
ret = pwrite(fd, (char *)mapped_mem + from, amount, to);
if (ret != amount) {
perror("pwrite");
exit(1);
}
munmap(mapped_mem,0);
close(fd);
exit(0);
}
|
