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 <unistd.h> 47 #include <fcntl.h> 48 #include <errno.h> 49 #include <sys/mman.h> 50 51 int 52 main(int argc, char **argv) 53 { 54 char *filename = "badfile"; 55 size_t size = 4395; 56 size_t idx = 0; 57 char *buf = NULL; 58 char *map = NULL; 59 int fd = -1, bytes, retval = 0; 60 unsigned seed; 61 62 if (argc < 2 || optind == argc) { 63 (void) fprintf(stderr, 64 "usage: %s <file name>\n", argv[0]); 65 exit(1); 66 } 67 68 if ((buf = calloc(1, size)) == NULL) { 69 perror("calloc"); 70 exit(1); 71 } 72 73 filename = argv[optind]; 74 75 (void) remove(filename); 76 77 fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666); 78 if (fd == -1) { 79 perror("open to create"); 80 retval = 1; 81 goto end; 82 } 83 84 bytes = write(fd, buf, size); 85 if (bytes != size) { 86 (void) printf("short write: %d != %zu\n", bytes, size); 87 retval = 1; 88 goto end; 89 } 90 91 map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); 92 if (map == MAP_FAILED) { 93 perror("mmap"); 94 retval = 1; 95 goto end; 96 } 97 seed = time(NULL); 98 srandom(seed); 99 100 idx = random() % size; 101 map[idx] = 1; 102 103 if (msync(map, size, MS_SYNC) != 0) { 104 perror("msync"); 105 retval = 1; 106 goto end; 107 } 108 109 if (munmap(map, size) != 0) { 110 perror("munmap"); 111 retval = 1; 112 goto end; 113 } 114 115 bytes = pread(fd, buf, size, 0); 116 if (bytes != size) { 117 (void) printf("short read: %d != %zu\n", bytes, size); 118 retval = 1; 119 goto end; 120 } 121 122 if (buf[idx] != 1) { 123 (void) printf( 124 "bad data from read! got buf[%zu]=%d, expected 1\n", 125 idx, buf[idx]); 126 retval = 1; 127 goto end; 128 } 129 130 (void) printf("good data from read: buf[%zu]=1\n", idx); 131 end: 132 if (fd != -1) { 133 (void) close(fd); 134 } 135 if (buf != NULL) { 136 free(buf); 137 } 138 139 return (retval); 140 } 141