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 __FBSDID("$FreeBSD$"); 40 41 #include <sys/socket.h> 42 43 #include <err.h> 44 #include <signal.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <unistd.h> 48 49 static void 50 receive_and_exit(int s) 51 { 52 ssize_t ssize; 53 char ch; 54 55 ssize = recv(s, &ch, sizeof(ch), 0); 56 if (ssize < 0) 57 err(-1, "receive_and_exit: recv"); 58 exit(0); 59 } 60 61 static void 62 shutdown_and_exit(int s) 63 { 64 65 if (shutdown(s, SHUT_RD) < 0) 66 err(-1, "shutdown_and_exit: shutdown"); 67 exit(0); 68 } 69 70 int 71 main(int argc, char *argv[]) 72 { 73 pid_t pida, pidb; 74 int sv[2]; 75 76 if (socketpair(PF_LOCAL, SOCK_STREAM, 0, sv) < 0) 77 err(-1, "socketpair"); 78 79 pida = fork(); 80 if (pida < 0) 81 err(-1, "fork"); 82 if (pida == 0) 83 receive_and_exit(sv[1]); 84 sleep(1); 85 pidb = fork(); 86 if (pidb < 0) { 87 warn("fork"); 88 (void)kill(pida, SIGKILL); 89 exit(-1); 90 } 91 if (pidb == 0) 92 shutdown_and_exit(sv[1]); 93 sleep(1); 94 if (kill(pidb, SIGKILL) < 0) 95 err(-1, "kill"); 96 sleep(1); 97 printf("ok 1 - unix_sorflush\n"); 98 exit(0); 99 } 100