1 /* $OpenBSD: fcntl_dup.c,v 1.3 2017/07/27 10:42:24 bluhm Exp $ */
2 /*
3 * Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
4 */
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <err.h>
9 #include <fcntl.h>
10
11 int
main(int argc,char * argv[])12 main(int argc, char *argv[])
13 {
14 int orgfd, fd1, fd2;
15 char temp[] = "/tmp/dup2XXXXXXXXX";
16
17 if ((orgfd = mkstemp(temp)) < 0)
18 err(1, "mkstemp");
19 remove(temp);
20
21 if (ftruncate(orgfd, 1024) != 0)
22 err(1, "ftruncate");
23
24 if ((fd1 = dup(orgfd)) < 0)
25 err(1, "dup");
26
27 /* Set close-on-exec */
28 if (fcntl(fd1, F_SETFD, 1) != 0)
29 err(1, "fcntl(F_SETFD)");
30
31 if ((fd2 = fcntl(fd1, F_DUPFD, 0)) < 0)
32 err(1, "fcntl(F_DUPFD)");
33
34 /* Test 2: Was close-on-exec cleared? */
35 if (fcntl(fd2, F_GETFD) != 0)
36 errx(1, "fcntl(F_DUPFD) didn't clear close-on-exec");
37
38 return 0;
39 }
40