o Add several regression tests for dup(2), dup2(2) and fcntl(F_DUPFD).

Obtained from:	OpenBSD

tools/regression/file/dup/Makefile

@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PROG=	dup
+NO_MAN=
+WARNS?=	6
+
+.include <bsd.prog.mk>

tools/regression/file/dup/dup.c

@@ -0,0 +1,160 @@
+/*
+ * $OpenBSD: dup2test.c,v 1.3 2003/07/31 21:48:08 deraadt Exp $
+ * $OpenBSD: dup2_self.c,v 1.3 2003/07/31 21:48:08 deraadt Exp $
+ * $OpenBSD: fcntl_dup.c,v 1.2 2003/07/31 21:48:08 deraadt Exp $
+ *
+ * Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Test #1:  check if dup(2) works.
+ * Test #2:  check if dup2(2) works.
+ * Test #3:  check if dup2(2) returned a fd we asked for.
+ * Test #4:  check if dup2(2) cleared close-on-exec flag for duped fd.
+ * Test #5:  check if dup2(2) allows to dup fd to itself.
+ * Test #6:  check if dup2(2) returned a fd we asked for.
+ * Test #7:  check if dup2(2) did not clear close-on-exec flag for duped fd.
+ * Test #8:  check if fcntl(F_DUPFD) works.
+ * Test #9:  check if fcntl(F_DUPFD) cleared close-on-exec flag for duped fd.
+ * Test #10: check if dup2() to a fd > current maximum number of open files
+ *           limit work.
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static int	getafile(void);
+
+static int
+getafile(void)
+{
+	int fd;
+
+	char temp[] = "/tmp/dup2XXXXXXXXX";
+	if ((fd = mkstemp(temp)) < 0)
+		err(1, "mkstemp");
+	remove(temp);
+	if (ftruncate(fd, 1024) != 0)
+		err(1, "ftruncate");
+	return (fd);
+}
+
+int
+main(int __unused argc, char __unused *argv[])
+{
+	struct rlimit rlp;
+	int orgfd, fd1, fd2, test = 0;
+
+	orgfd = getafile();
+
+	printf("1..10\n");
+
+	/* If dup(2) ever work? */
+	if ((fd1 = dup(orgfd)) < 0)
+		err(1, "dup");
+	printf("ok %d - dup(2) works\n", ++test);
+
+	/* Set close-on-exec */
+	if (fcntl(fd1, F_SETFD, 1) != 0)
+		err(1, "fcntl(F_SETFD)");
+
+	/* If dup2(2) ever work? */
+	if ((fd2 = dup2(fd1, fd1 + 1)) < 0)
+		err(1, "dup2");
+	printf("ok %d - dup2(2) works\n", ++test);
+
+	/* Do we get the right fd? */
+	++test;
+	if (fd2 != fd1 + 1)
+		printf("no ok %d - dup2(2) didn't give us the right fd\n",
+		    test);
+	else
+		printf("ok %d - dup2(2) returned a correct fd\n", test);
+
+	/* Was close-on-exec cleared? */
+	++test;
+	if (fcntl(fd2, F_GETFD) != 0)
+		printf("not ok %d - dup2(2) didn't clear close-on-exec\n",
+		    test);
+	else
+		printf("ok %d - dup2(2) cleared close-on-exec\n", test);
+
+	/*
+	 * Dup to itself.
+	 *
+	 * We're testing a small tweak in dup2 semantics.
+	 * Normally dup and dup2 will clear the close-on-exec
+	 * flag on the new fd (which appears to be an implementation
+	 * mistake from start and not some planned behavior).
+	 * In todays implementations of dup and dup2 we have to make
+	 * an effort to really clear that flag.  But all tested
+	 * implementations of dup2 have another tweak.  If we
+	 * dup2(old, new) when old == new, the syscall short-circuits
+	 * and returns early (because there is no need to do all the
+	 * work (and there is a risk for serious mistakes)).
+	 * So although the docs say that dup2 should "take 'old',
+	 * close 'new' perform a dup(2) of 'old' into 'new'"
+	 * the docs are not really followed because close-on-exec
+	 * is not cleared on 'new'.
+	 *
+	 * Since everyone has this bug, we pretend that this is
+	 * the way it is supposed to be and test here that it really
+	 * works that way.
+	 *
+	 * This is a fine example on where two separate implementation
+	 * fuckups take out each other and make the end-result the way
+	 * it was meant to be.
+	 */
+        if ((fd2 = dup2(fd1, fd1)) < 0)
+		err(1, "dup2");
+	printf("ok %d - dup2(2) to itself works\n", ++test);
+
+	/* Do we get the right fd? */
+	++test;
+	if (fd2 != fd1)
+		printf("not ok %d - dup2(2) didn't give us the right fd\n",
+		    test);
+	else
+		printf("ok %d - dup2(2) to itself returned a correct fd\n",
+		    test);
+
+	/* Was close-on-exec cleared? */
+	++test;
+	if (fcntl(fd2, F_GETFD) == 0)
+		printf("not ok %d - dup2(2) cleared close-on-exec\n", test);
+	else
+		printf("ok %d - dup2(2) didn't clear close-on-exec\n", test);
+
+	/* Does fcntl(F_DUPFD) work? */
+	if ((fd2 = fcntl(fd1, F_DUPFD)) < 0)
+		err(1, "fcntl(F_DUPFD)");
+	printf("ok %d - fcntl(F_DUPFD) works\n", ++test);
+
+	/* Was close-on-exec cleared? */
+	++test;
+        if (fcntl(fd2, F_GETFD) != 0)
+		printf(
+		    "not ok %d - fcntl(F_DUPFD) didn't clear close-on-exec\n",
+		    test);
+	else
+		printf("ok %d - fcntl(F_DUPFD) cleared close-on-exec\n", test);
+
+	++test;
+	if (getrlimit(RLIMIT_NOFILE, &rlp) < 0)
+		err(1, "getrlimit");
+        if ((fd2 = dup2(fd1, rlp.rlim_cur + 1)) == 0)
+		printf("not ok %d - dup2(2) bypassed NOFILE limit\n", test);
+	else
+		printf("ok %d - dup2(2) didn't bypass NOFILE limit\n", test);
+
+	return (0);
+}

tools/regression/file/dup/dup.t

@@ -0,0 +1,10 @@
+#!/bin/sh
+# $FreeBSD$
+
+cd `dirname $0`
+
+executable=`basename $0 .t`
+
+make $executable 2>&1 > /dev/null
+
+exec ./$executable