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