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 */
21
22 /*
23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27
28 #include <unistd.h>
29 #include <fcntl.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <sys/mman.h>
33 #include <pthread.h>
34
35 /*
36 * --------------------------------------------------------------------
37 * Bug Id: 5032643
38 *
39 * Simply writing to a file and mmaping that file at the same time can
40 * result in deadlock. Nothing perverse like writing from the file's
41 * own mapping is required.
42 * --------------------------------------------------------------------
43 */
44
45 static void *
mapper(void * fdp)46 mapper(void *fdp)
47 {
48 void *addr;
49 int fd = *(int *)fdp;
50
51 if ((addr =
52 mmap(0, 8192, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
53 perror("mmap");
54 exit(1);
55 }
56 for (;;) {
57 if (mmap(addr, 8192, PROT_READ,
58 MAP_SHARED|MAP_FIXED, fd, 0) == MAP_FAILED) {
59 perror("mmap");
60 exit(1);
61 }
62 }
63 /* NOTREACHED */
64 return ((void *)1);
65 }
66
67 int
main(int argc,char ** argv)68 main(int argc, char **argv)
69 {
70 int fd;
71 char buf[BUFSIZ];
72 pthread_t pt;
73
74 if (argc != 2) {
75 (void) printf("usage: %s <file name>\n", argv[0]);
76 exit(1);
77 }
78
79 if ((fd = open(argv[1], O_RDWR|O_CREAT|O_TRUNC, 0666)) == -1) {
80 perror("open");
81 exit(1);
82 }
83
84 if (pthread_create(&pt, NULL, mapper, &fd) != 0) {
85 perror("pthread_create");
86 exit(1);
87 }
88 for (;;) {
89 if (write(fd, buf, sizeof (buf)) == -1) {
90 perror("write");
91 exit(1);
92 }
93 }
94
95 /* NOTREACHED */
96 return (0);
97 }
98