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 https://opensource.org/licenses/CDDL-1.0.
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  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * --------------------------------------------------------------
29  *	BugId 5047993 : Getting bad read data.
30  *
31  *	Usage: readmmap <filename>
32  *
33  *	where:
34  *		filename is an absolute path to the file name.
35  *
36  *	Return values:
37  *		1 : error
38  *		0 : no errors
39  * --------------------------------------------------------------
40  */
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <unistd.h>
44 #include <fcntl.h>
45 #include <errno.h>
46 #include <sys/mman.h>
47 #include <time.h>
48 
49 int
50 main(int argc, char **argv)
51 {
52 	const char *filename = "badfile";
53 	size_t size = 4395;
54 	size_t idx = 0;
55 	char *buf = NULL;
56 	char *map = NULL;
57 	int fd = -1, bytes, retval = 0;
58 	unsigned seed;
59 
60 	if (argc < 2 || optind == argc) {
61 		(void) fprintf(stderr,
62 		    "usage: %s <file name>\n", argv[0]);
63 		exit(1);
64 	}
65 
66 	if ((buf = calloc(1, size)) == NULL) {
67 		perror("calloc");
68 		exit(1);
69 	}
70 
71 	filename = argv[optind];
72 
73 	(void) remove(filename);
74 
75 	fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666);
76 	if (fd == -1) {
77 		perror("open to create");
78 		retval = 1;
79 		goto end;
80 	}
81 
82 	bytes = write(fd, buf, size);
83 	if (bytes != size) {
84 		(void) printf("short write: %d != %zd\n", bytes, size);
85 		retval = 1;
86 		goto end;
87 	}
88 
89 	map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
90 	if (map == MAP_FAILED) {
91 		perror("mmap");
92 		retval = 1;
93 		goto end;
94 	}
95 	seed = time(NULL);
96 	srandom(seed);
97 
98 	idx = random() % size;
99 	map[idx] = 1;
100 
101 	if (msync(map, size, MS_SYNC) != 0) {
102 		perror("msync");
103 		retval = 1;
104 		goto end;
105 	}
106 
107 	if (munmap(map, size) != 0) {
108 		perror("munmap");
109 		retval = 1;
110 		goto end;
111 	}
112 
113 	bytes = pread(fd, buf, size, 0);
114 	if (bytes != size) {
115 		(void) printf("short read: %d != %zd\n", bytes, size);
116 		retval = 1;
117 		goto end;
118 	}
119 
120 	if (buf[idx] != 1) {
121 		(void) printf(
122 		    "bad data from read!  got buf[%zd]=%d, expected 1\n",
123 		    idx, buf[idx]);
124 		retval = 1;
125 		goto end;
126 	}
127 
128 	(void) printf("good data from read: buf[%zd]=1\n", idx);
129 end:
130 	if (fd != -1) {
131 		(void) close(fd);
132 	}
133 	if (buf != NULL) {
134 		free(buf);
135 	}
136 
137 	return (retval);
138 }
139