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