1#!/bin/sh 2 3# 4# Copyright (c) 2015 EMC Corp. 5# All rights reserved. 6# 7# Redistribution and use in source and binary forms, with or without 8# modification, are permitted provided that the following conditions 9# are met: 10# 1. Redistributions of source code must retain the above copyright 11# notice, this list of conditions and the following disclaimer. 12# 2. Redistributions in binary form must reproduce the above copyright 13# notice, this list of conditions and the following disclaimer in the 14# documentation and/or other materials provided with the distribution. 15# 16# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26# SUCH DAMAGE. 27# 28 29# flock(2) read (shared) lock test. 30 31# FAIL: Unfair scheduling? 32# share[1] = 359171 33# share[2] = 394437 34# share[3] = 359488 35# share[4] = 394429 36# share[5] = 359441 37# share[6] = 394281 38# share[7] = 359314 39# share[8] = 394615 40 41. ../default.cfg 42 43[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1 44 45dir=/tmp 46odir=`pwd` 47cd $dir 48sed '1,/^EOF/d' < $odir/$0 > $dir/flock.c 49mycc -o flock -Wall -Wextra -O0 -g flock.c || exit 1 50rm -f flock.c 51cd $odir 52 53mount | grep "on $mntpoint " | grep -q /dev/md && umount -f $mntpoint 54mdconfig -l | grep -q md$mdstart && mdconfig -d -u $mdstart 55mdconfig -a -t swap -s 1g -u $mdstart || exit 1 56newfs $newfs_flags md$mdstart > /dev/null 57mount /dev/md$mdstart $mntpoint 58 59(cd $mntpoint; /tmp/flock) 60e=$? 61 62while mount | grep "on $mntpoint " | grep -q /dev/md; do 63 umount $mntpoint || sleep 1 64done 65mdconfig -d -u $mdstart 66rm -rf /tmp/flock 67exit $e 68 69EOF 70#include <sys/param.h> 71#include <sys/mman.h> 72#include <sys/stat.h> 73#include <sys/wait.h> 74 75#include <machine/atomic.h> 76 77#include <err.h> 78#include <errno.h> 79#include <fcntl.h> 80#include <stdio.h> 81#include <stdlib.h> 82#include <string.h> 83#include <time.h> 84#include <unistd.h> 85 86volatile u_int *share; 87int fd; 88 89#define RENDEZVOUS 0 90 91#define CHILDREN 8 92#define LOOPS 8000 93#define PARALLEL 1 94#define RUNTIME (1 * 60) 95 96void 97chld(int id) 98{ 99 while (share[RENDEZVOUS] == 0) 100 ; 101 102 while (share[RENDEZVOUS] == 1) { 103 if (flock(fd, LOCK_SH) == -1) 104 err(1, "fcntl @ %d", __LINE__); 105 atomic_add_int(&share[id + 1], 1); 106 if (flock(fd, LOCK_UN) == -1) 107 err(1, "fcntl @ %d", __LINE__); 108 usleep(100); 109 } 110 111 _exit(0); 112} 113 114void 115test(void) 116{ 117 int i; 118 char file[80]; 119 120 snprintf(file, sizeof(file), "file.%05d", getpid()); 121 if ((fd = open(file, O_RDWR | O_CREAT, 0640)) == -1) 122 err(1, "open(%s)", file); 123 if (flock(fd, LOCK_EX) == -1) 124 err(1, "fcntl @ %d", __LINE__); 125 126 for (i = 0; i < CHILDREN; i++) { 127 if (fork() == 0) 128 chld(i); 129 } 130 131 usleep(200); 132 atomic_add_int(&share[RENDEZVOUS], 1); /* start chld */ 133 for (i = 0; i < LOOPS; i++) { 134 if (flock(fd, LOCK_UN) == -1) 135 err(1, "fcntl @ %d", __LINE__); 136 if (flock(fd, LOCK_EX) == -1) 137 err(1, "fcntl @ %d", __LINE__); 138 } 139 atomic_add_int(&share[RENDEZVOUS], 1); /* stop chld */ 140 141 for (i = 0; i < CHILDREN; i++) 142 wait(NULL); 143 144 close(fd); 145 unlink(file); 146 147 _exit(0); 148} 149 150int 151main(void) 152{ 153 size_t len; 154 time_t start; 155 int i, n, pct; 156 157 len = getpagesize(); 158 if ((share = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_ANON | 159 MAP_SHARED, -1, 0)) == MAP_FAILED) 160 err(1, "mmap"); 161 162 start = time(NULL); 163 while ((time(NULL) - start) < RUNTIME) { 164 share[RENDEZVOUS] = 0; 165 for (i = 0; i < PARALLEL; i++) { 166 if (fork() == 0) 167 test(); 168 } 169 for (i = 0; i < PARALLEL; i++) 170 wait(NULL); 171 } 172 n = 0; 173 for (i = 0; i < CHILDREN; i++) 174 n += share[i + 1]; 175 n /= CHILDREN; 176 for (i = 0; i < CHILDREN; i++) { 177 pct = abs((int)share[i + 1] - n) * 100 / n; 178 if (pct > 1) { 179 fprintf(stderr, "Unfair scheduling?\n"); 180 for (i = 0; i < CHILDREN; i++) { 181 pct = abs((int)share[i + 1] - n) * 100 / n; 182 fprintf(stderr, "share[%d] = %d\n", 183 i+1, share[i+1]); 184 } 185 break; 186 } 187 } 188 189 return (0); 190} 191