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
55 static char socket_path[] = "tmp.XXXXXXXX";
56
57 #define USLEEP 100
58 #define LOOPS 100000
59
60 int
main(void)61 main(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