1/*-
2 * Copyright (c) 2010 Mikolaj Golub
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 * $FreeBSD$
27 */
28
29/*
30 * This regression test attempts to trigger a race that occurs when both
31 * endpoints of a connected UNIX domain socket are closed at once.  The two
32 * close paths may run concurrently leading to a call to sodisconnect() on an
33 * already-closed socket in kernel.  Before it was fixed, this might lead to
34 * ENOTCONN being returned improperly from close().
35 *
36 * This race is fairly timing-dependent, so it effectively requires SMP, and
37 * may not even trigger then.
38 */
39
40#include <sys/types.h>
41#include <sys/select.h>
42#include <sys/socket.h>
43#include <sys/sysctl.h>
44#include <sys/un.h>
45#include <netinet/in.h>
46#include <arpa/inet.h>
47#include <errno.h>
48#include <fcntl.h>
49#include <signal.h>
50#include <stdlib.h>
51#include <stdio.h>
52#include <strings.h>
53#include <string.h>
54#include <unistd.h>
55#include <err.h>
56
57static char socket_path[] = "tmp.XXXXXXXX";
58
59#define	USLEEP	100
60#define	LOOPS	100000
61
62int
63main(void)
64{
65	struct sockaddr_un servaddr;
66	int listenfd, connfd, pid;
67	u_int counter, ncpus;
68	size_t len;
69
70	len = sizeof(ncpus);
71	if (sysctlbyname("kern.smp.cpus", &ncpus, &len, NULL, 0) < 0)
72		err(1, "kern.smp.cpus");
73	if (len != sizeof(ncpus))
74		errx(1, "kern.smp.cpus: invalid length");
75	if (ncpus < 2)
76		warnx("SMP not present, test may be unable to trigger race");
77
78	if (mkstemp(socket_path) == -1)
79		err(1, "mkstemp failed");
80	unlink(socket_path);
81
82	/*
83	 * Create a UNIX domain socket that the child will repeatedly
84	 * accept() from, and that the parent will repeatedly connect() to.
85	 */
86	if ((listenfd = socket(AF_LOCAL, SOCK_STREAM, 0)) < 0)
87		err(1, "parent: socket error");
88	(void)unlink(socket_path);
89	bzero(&servaddr, sizeof(servaddr));
90	servaddr.sun_family = AF_LOCAL;
91	strcpy(servaddr.sun_path, socket_path);
92	if (bind(listenfd, (struct sockaddr *) &servaddr,
93	    sizeof(servaddr)) < 0)
94		err(1, "parent: bind error");
95	if (listen(listenfd, 1024) < 0)
96		err(1, "parent: listen error");
97
98	pid = fork();
99	if (pid == -1)
100		err(1, "fork()");
101	if (pid != 0) {
102		/*
103		 * In the parent, repeatedly connect and disconnect from the
104		 * socket, attempting to induce the race.
105		 */
106		close(listenfd);
107		sleep(1);
108		bzero(&servaddr, sizeof(servaddr));
109		servaddr.sun_family = AF_LOCAL;
110		strcpy(servaddr.sun_path, socket_path);
111		for (counter = 0; counter < LOOPS; counter++) {
112			if ((connfd = socket(AF_LOCAL, SOCK_STREAM, 0)) < 0) {
113				(void)kill(pid, SIGTERM);
114				err(1, "parent: socket error");
115			}
116			if (connect(connfd, (struct sockaddr *)&servaddr,
117			    sizeof(servaddr)) < 0) {
118			    	(void)kill(pid, SIGTERM);
119				err(1, "parent: connect error");
120			}
121			if (close(connfd) < 0) {
122				(void)kill(pid, SIGTERM);
123				err(1, "parent: close error");
124			}
125			usleep(USLEEP);
126		}
127		(void)kill(pid, SIGTERM);
128	} else {
129		/*
130		 * In the child, loop accepting and closing.  We may pick up
131		 * the race here so report errors from close().
132		 */
133		for ( ; ; ) {
134			if ((connfd = accept(listenfd,
135			    (struct sockaddr *)NULL, NULL)) < 0)
136				err(1, "child: accept error");
137			if (close(connfd) < 0)
138				err(1, "child: close error");
139		}
140	}
141	printf("OK\n");
142	exit(0);
143}
144