beneath2.sh

#!/bin/sh

#
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2018 Dell EMC Isilon
#
# 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.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
#

# O_RESOLVE_BENEATH test with a relative path, which is a symbolic link pointing
# to an absolute path.

# "panic: Assertion (ndp->ni_lcf & NI_LCF_LATCH) != 0 failed at
# ../../../kern/vfs_lookup.c:182" seen. Fixed by r340343.

# Based on scenario by Vladimir Kondratyev <vladimir kondratyev su>

. ../default.cfg
[ `id -u` -ne 0 ] && echo "Must be root!" && exit 1

dir=/tmp
odir=`pwd`
cd $dir
sed '1,/^EOF/d' < $odir/$0 > $dir/beneath2.c
mycc -o beneath2 -Wall -Wextra -O0 -g beneath2.c || exit 1
rm -f beneath2.c
cd $odir

set -e
mount | grep "on $mntpoint " | grep -q /dev/md && umount -f $mntpoint
[ -c /dev/md$mdstart ] &&  mdconfig -d -u $mdstart
mdconfig -a -t swap -s 1g -u $mdstart
newfs $newfs_flags md$mdstart > /dev/null
mount /dev/md$mdstart $mntpoint
set +e

cd $mntpoint
ln -s /tmp/justalongname symlink
$dir/beneath2 symlink
s=$?
[ -f beneath2.core -a $s -eq 0 ] &&
    { ls -l beneath2.core; mv beneath2.core $dir; s=1; }
cd $odir

for i in `jot 6`; do
	mount | grep -q "on $mntpoint " || break
	umount $mntpoint && break || sleep 10
	[ $i -eq 6 ] &&
	    { echo FATAL; fstat -mf $mntpoint; exit 1; }
done
mdconfig -d -u $mdstart
rm -rf $dir/beneath2
exit $s

EOF
#include <sys/types.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
	int fd;
	char *file;

	if (argc != 2) {
		fprintf(stderr, "Usage: %s <file>", argv[0]);
		exit(1);
	}
	file = argv[1];
	if ((fd = open(file, O_RDONLY | O_RESOLVE_BENEATH)) != 0 &&
	    errno != ENOTCAPABLE)
		err(1, "open(%s)", file);

	return (0);
}