1 files changed, 129 insertions, 0 deletions
diff --git a/sbin/mount_nullfs/mount_nullfs.c b/sbin/mount_nullfs/mount_nullfs.c
new file mode 100644
index 000000000000..e8c26df1b8f9
--- /dev/null
+++ b/sbin/mount_nullfs/mount_nullfs.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 1992, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software donated to Berkeley by
+ * Jan-Simon Pendry.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+char copyright[] =
+"@(#) Copyright (c) 1992, 1993, 1994\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)mount_null.c	8.5 (Berkeley) 3/27/94";
+#endif /* not lint */
+
+#include <sys/param.h>
+#include <sys/mount.h>
+#include <miscfs/nullfs/null.h>
+
+#include <err.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mntopts.h"
+
+struct mntopt mopts[] = {
+	MOPT_STDOPTS,
+	{ NULL }
+};
+
+int	subdir __P((const char *, const char *));
+void	usage __P((void));
+
+int
+main(argc, argv)
+	int argc;
+	char *argv[];
+{
+	struct null_args args;
+	int ch, mntflags;
+	char target[MAXPATHLEN];
+
+	mntflags = 0;
+	while ((ch = getopt(argc, argv, "o:")) != EOF)
+		switch(ch) {
+		case 'o':
+			getmntopts(optarg, mopts, &mntflags);
+			break;
+		case '?':
+		default:
+			usage();
+		}
+	argc -= optind;
+	argv += optind;
+
+	if (argc != 2)
+		usage();
+
+	if (realpath(argv[0], target) == 0)
+		err(1, "%s", target);
+
+	if (subdir(target, argv[1]) || subdir(argv[1], target))
+		errx(1, "%s (%s) and %s are not distinct paths",
+		    argv[0], target, argv[1]);
+
+	args.target = target;
+
+	if (mount(MOUNT_NULL, argv[1], mntflags, &args))
+		err(1, NULL);
+	exit(0);
+}
+
+int
+subdir(p, dir)
+	const char *p;
+	const char *dir;
+{
+	int l;
+
+	l = strlen(dir);
+	if (l <= 1)
+		return (1);
+
+	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
+		return (1);
+
+	return (0);
+}
+
+void
+usage()
+{
+	(void)fprintf(stderr,
+		"usage: mount_null [-o options] target_fs mount_point\n");
+	exit(1);
+}