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 #include <sys/socket.h>
40
41 #include <err.h>
42 #include <signal.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <unistd.h>
46
47 static void
receive_and_exit(int s)48 receive_and_exit(int s)
49 {
50 ssize_t ssize;
51 char ch;
52
53 ssize = recv(s, &ch, sizeof(ch), 0);
54 if (ssize < 0)
55 err(-1, "receive_and_exit: recv");
56 exit(0);
57 }
58
59 static void
shutdown_and_exit(int s)60 shutdown_and_exit(int s)
61 {
62
63 if (shutdown(s, SHUT_RD) < 0)
64 err(-1, "shutdown_and_exit: shutdown");
65 exit(0);
66 }
67
68 int
main(void)69 main(void)
70 {
71 pid_t pida, pidb;
72 int sv[2];
73
74 if (socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0)
75 err(-1, "socketpair");
76
77 pida = fork();
78 if (pida < 0)
79 err(-1, "fork");
80 if (pida == 0)
81 receive_and_exit(sv[1]);
82 sleep(1);
83 pidb = fork();
84 if (pidb < 0) {
85 warn("fork");
86 (void)kill(pida, SIGKILL);
87 exit(-1);
88 }
89 if (pidb == 0)
90 shutdown_and_exit(sv[1]);
91 sleep(1);
92 if (kill(pidb, SIGKILL) < 0)
93 err(-1, "kill");
94 sleep(1);
95 printf("ok 1 - unix_sorflush\n");
96 exit(0);
97 }
98