1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 * $FreeBSD$ 21 */ 22 23 /* 24 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 25 * Use is subject to license terms. 26 */ 27 28 #pragma ident "@(#)readmmap.c 1.4 07/05/25 SMI" 29 30 /* 31 * -------------------------------------------------------------- 32 * BugId 5047993 : Getting bad read data. 33 * 34 * Usage: readmmap <filename> 35 * 36 * where: 37 * filename is an absolute path to the file name. 38 * 39 * Return values: 40 * 1 : error 41 * 0 : no errors 42 * -------------------------------------------------------------- 43 */ 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <time.h> 47 #include <unistd.h> 48 #include <fcntl.h> 49 #include <errno.h> 50 #include <sys/mman.h> 51 52 int 53 main(int argc, char **argv) 54 { 55 char *filename = "badfile"; 56 size_t size = 4395; 57 size_t idx = 0; 58 char *buf = NULL; 59 char *map = NULL; 60 int fd = -1, bytes, retval = 0; 61 unsigned seed; 62 63 if (argc < 2 || optind == argc) { 64 (void) fprintf(stderr, 65 "usage: %s <file name>\n", argv[0]); 66 exit(1); 67 } 68 69 if ((buf = calloc(1, size)) == NULL) { 70 perror("calloc"); 71 exit(1); 72 } 73 74 filename = argv[optind]; 75 76 (void) remove(filename); 77 78 fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666); 79 if (fd == -1) { 80 perror("open to create"); 81 retval = 1; 82 goto end; 83 } 84 85 bytes = write(fd, buf, size); 86 if (bytes != size) { 87 (void) printf("short write: %d != %zu\n", bytes, size); 88 retval = 1; 89 goto end; 90 } 91 92 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); 93 if (map == MAP_FAILED) { 94 perror("mmap"); 95 retval = 1; 96 goto end; 97 } 98 seed = time(NULL); 99 srandom(seed); 100 101 idx = random() % size; 102 map[idx] = 1; 103 104 if (msync(map, size, MS_SYNC) != 0) { 105 perror("msync"); 106 retval = 1; 107 goto end; 108 } 109 110 if (munmap(map, size) != 0) { 111 perror("munmap"); 112 retval = 1; 113 goto end; 114 } 115 116 bytes = pread(fd, buf, size, 0); 117 if (bytes != size) { 118 (void) printf("short read: %d != %zu\n", bytes, size); 119 retval = 1; 120 goto end; 121 } 122 123 if (buf[idx] != 1) { 124 (void) printf( 125 "bad data from read! got buf[%zu]=%d, expected 1\n", 126 idx, buf[idx]); 127 retval = 1; 128 goto end; 129 } 130 131 (void) printf("good data from read: buf[%zu]=1\n", idx); 132 end: 133 if (fd != -1) { 134 (void) close(fd); 135 } 136 if (buf != NULL) { 137 free(buf); 138 } 139 140 return (retval); 141 } 142