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 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