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 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 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 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