preadv.c revision 1.3 
1/*	$OpenBSD: preadv.c,v 1.3 2011/11/05 15:43:04 guenther Exp $	*/
2/*
3 *	Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
4 */
5#include <sys/types.h>
6#include <sys/uio.h>
7#include <stdio.h>
8#include <stdlib.h>
9#include <unistd.h>
10#include <err.h>
11#include <errno.h>
12#include <fcntl.h>
13
14int
15main(int argc, char *argv[])
16{
17	char temp[] = "/tmp/dup2XXXXXXXXX";
18	const char magic[10] = "0123456789";
19	char c, c1, c2;
20	int fd, ret;
21	struct iovec iv[2];
22
23	if ((fd = mkstemp(temp)) < 0)
24		err(1, "mkstemp");
25	remove(temp);
26
27	if (write(fd, magic, sizeof(magic)) != sizeof(magic))
28		err(1, "write");
29
30	if (lseek(fd, 0, SEEK_SET) != 0)
31		err(1, "lseek");
32
33	if (read(fd, &c, 1) != 1)
34		err(1, "read1");
35
36	if (c != magic[0])
37		errx(1, "read1 %c != %c", c, magic[0]);
38
39	iv[0].iov_base = &c1;
40	iv[0].iov_len = 1;
41	iv[1].iov_base = &c2;
42	iv[1].iov_len = 1;
43
44	if (preadv(fd, iv, 2, 7) != 2)
45		err(1, "preadv");
46
47	if (c1 != magic[7])
48		errx(1, "preadv %c != %c", c1, magic[7]);
49
50	if (c2 != magic[8])
51		errx(1, "preadv %c != %c", c2, magic[7]);
52
53	if (read(fd, &c, 1) != 1)
54		err(1, "read2");
55
56	if (c != magic[1])
57		errx(1, "read2 %c != %c", c, magic[1]);
58
59	close(fd);
60
61	/* also, verify that preadv fails on ttys */
62	fd = open("/dev/tty", O_RDWR);
63	if (fd < 0)
64		printf("skipping tty test\n");
65	else if ((ret = preadv(fd, iv, 2, 7)) != -1)
66		errx(1, "preadv succeeded on tty, returning %d", ret);
67	else if (errno != ESPIPE)
68		err(1, "preadv");
69
70	return 0;
71}
72