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
|
/* $OpenBSD: pwrite.c,v 1.3 2003/09/02 23:52:17 david Exp $ */
/*
* Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#include <fcntl.h>
int
main(int argc, char *argv[])
{
char temp[] = "/tmp/pwriteXXXXXXXXX";
const char magic[10] = "0123456789";
const char zeroes[10] = "0000000000";
char buf[10];
char c;
int fd;
if ((fd = mkstemp(temp)) < 0)
err(1, "mkstemp");
remove(temp);
if (write(fd, zeroes, sizeof(zeroes)) != sizeof(zeroes))
err(1, "write");
if (lseek(fd, 5, SEEK_SET) != 5)
err(1, "lseek");
if (pwrite(fd, &magic[1], 4, 4) != 4)
err(1, "pwrite");
if (read(fd, &c, 1) != 1)
err(1, "read");
if (c != '2')
errx(1, "read %c != %c", c, '2');
c = '5';
if (write(fd, &c, 1) != 1)
err(1, "write");
if (pread(fd, buf, 10, 0) != 10)
err(1, "pread");
if (memcmp(buf, "0000125400", 10) != 0)
errx(1, "data mismatch: %s != %s", buf, "0000125400");
return 0;
}
|
