1/*-
2 * Copyright (c) 2008 Robert N. M. Watson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27/*
28 * Reproduce a race in which:
29 *
30 * - Process (a) is blocked in read on a socket waiting on data.
31 * - Process (b) is blocked in shutdown() on a socket waiting on (a).
32 * - Process (c) delivers a signal to (b) interrupting its wait.
33 *
34 * This race is premised on shutdown() not interrupting (a) properly, and the
35 * signal to (b) causing problems in the kernel.
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include <sys/socket.h>
42
43#include <err.h>
44#include <signal.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <unistd.h>
48
49static void
50receive_and_exit(int s)
51{
52	ssize_t ssize;
53	char ch;
54
55	ssize = recv(s, &ch, sizeof(ch), 0);
56	if (ssize < 0)
57		err(-1, "receive_and_exit: recv");
58	exit(0);
59}
60
61static void
62shutdown_and_exit(int s)
63{
64
65	if (shutdown(s, SHUT_RD) < 0)
66		err(-1, "shutdown_and_exit: shutdown");
67	exit(0);
68}
69
70int
71main(void)
72{
73	pid_t pida, pidb;
74	int sv[2];
75
76	if (socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0)
77		err(-1, "socketpair");
78
79	pida = fork();
80	if (pida < 0)
81		err(-1, "fork");
82	if (pida == 0)
83		receive_and_exit(sv[1]);
84	sleep(1);
85	pidb = fork();
86	if (pidb < 0) {
87		warn("fork");
88		(void)kill(pida, SIGKILL);
89		exit(-1);
90	}
91	if (pidb == 0)
92		shutdown_and_exit(sv[1]);
93	sleep(1);
94	if (kill(pidb, SIGKILL) < 0)
95		err(-1, "kill");
96	sleep(1);
97	printf("ok 1 - unix_sorflush\n");
98	exit(0);
99}
100