1 /* $OpenBSD: pread.c,v 1.4 2011/11/06 15:00:34 guenther Exp $ */
2 /*
3 * Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
4 */
5 #include <err.h>
6 #include <errno.h>
7 #include <fcntl.h>
8 #include <limits.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <unistd.h>
12
13 int
main(int argc,char * argv[])14 main(int argc, char *argv[])
15 {
16 char temp[] = "/tmp/dup2XXXXXXXXX";
17 const char magic[10] = "0123456789";
18 char c;
19 int fd, ret;
20
21 if ((fd = mkstemp(temp)) < 0)
22 err(1, "mkstemp");
23 remove(temp);
24
25 if (write(fd, magic, sizeof(magic)) != sizeof(magic))
26 err(1, "write");
27
28 if (lseek(fd, 0, SEEK_SET) != 0)
29 err(1, "lseek");
30
31 if (read(fd, &c, 1) != 1)
32 err(1, "read1");
33
34 if (c != magic[0])
35 errx(1, "read1 %c != %c", c, magic[0]);
36
37 if (pread(fd, &c, 1, 7) != 1)
38 err(1, "pread");
39
40 if (c != magic[7])
41 errx(1, "pread %c != %c", c, magic[7]);
42
43 if (read(fd, &c, 1) != 1)
44 err(1, "read2");
45
46 if (c != magic[1])
47 errx(1, "read2 %c != %c", c, magic[1]);
48
49 if ((ret = pread(fd, &c, 1, -1)) != -1)
50 errx(1, "pread with negative offset succeeded,\
51 returning %d", ret);
52 if (errno != EINVAL)
53 err(1, "pread with negative offset");
54
55 if ((ret = pread(fd, &c, 3, LLONG_MAX)) != -1)
56 errx(1, "pread with wrapping offset succeeded,\
57 returning %d", ret);
58 if (errno != EINVAL)
59 err(1, "pread with wrapping offset");
60
61 if (read(fd, &c, 1) != 1)
62 err(1, "read3");
63
64 if (c != magic[2])
65 errx(1, "read3 %c != %c", c, magic[2]);
66
67 close(fd);
68
69 /* also, verify that pread fails on ttys */
70 fd = open("/dev/tty", O_RDWR);
71 if (fd < 0)
72 printf("skipping tty test\n");
73 else if ((ret = pread(fd, &c, 1, 7)) != -1)
74 errx(1, "pread succeeded on tty, returning %d", ret);
75 else if (errno != ESPIPE)
76 err(1, "pread");
77
78 return 0;
79 }
80