1 /*
2 * Copyright (c) 2002, Intel Corporation. All rights reserved.
3 * Copyright (c) 2012, Cyril Hrubis <chrubis@suse.cz>
4 *
5 * This file is licensed under the GPL license. For the full content
6 * of this license, see the COPYING file at the top level of this
7 * source tree.
8 *
9 * MAP_SHARED and MAP_PRIVATE describe the disposition of write references
10 * to the memory object. If MAP_SHARED is specified, write references shall
11 * change the underlying object. If MAP_PRIVATE is specified, modifications
12 * to the mapped data by the calling process shall be visible only to the
13 * calling process and shall not change the underlying object.
14 * It is unspecified whether modifications to the underlying object done
15 * after the MAP_PRIVATE mapping is established are visible through
16 * the MAP_PRIVATE mapping.
17 *
18 * Test Steps:
19 *
20 * 1. Create a shared memory object.
21 * 2. mmap the shared memory object into memory, setting MAP_SHARED.
22 * 3. Modify the mapped memory.
23 * 4. Fork a child process.
24 * 5. Child process mmap the same shared memory object into memory.
25 * 6. Check whether the change in step 3 is visible to the child.
26 */
27
28 #define _XOPEN_SOURCE 600
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <sys/mman.h>
33 #include <sys/types.h>
34 #include <sys/stat.h>
35 #include <sys/wait.h>
36 #include <fcntl.h>
37 #include <string.h>
38 #include <errno.h>
39 #include "posixtest.h"
40
main(void)41 int main(void)
42 {
43 char tmpfname[256];
44 int shm_fd;
45 void *pa;
46 size_t size = 1024;
47
48 pid_t child;
49
50 int exit_stat;
51
52 /* Create shared object */
53 snprintf(tmpfname, sizeof(tmpfname), "pts_mmap_7_4_%d", getpid());
54 shm_unlink(tmpfname);
55 shm_fd =
56 shm_open(tmpfname, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
57 if (shm_fd == -1) {
58 printf("Error at shm_open(): %s\n", strerror(errno));
59 return PTS_UNRESOLVED;
60 }
61 shm_unlink(tmpfname);
62
63 /* Set the size of the shared memory object */
64 if (ftruncate(shm_fd, size) == -1) {
65 printf("Error at ftruncate(): %s\n", strerror(errno));
66 return PTS_UNRESOLVED;
67 }
68
69 pa = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
70 if (pa == MAP_FAILED) {
71 printf("Error at mmap: %s\n", strerror(errno));
72 return PTS_FAIL;
73 }
74
75 /* Write the mapped memory */
76 *(char *)pa = 'a';
77
78 child = fork();
79 switch (child) {
80 case 0:
81 /* Mmap again the same shared memory to child's memory */
82 pa = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
83 shm_fd, 0);
84 if (pa == MAP_FAILED) {
85 printf("child: Error at mmap: %s\n", strerror(errno));
86 return PTS_FAIL;
87 }
88
89 if (*(char *)pa == 'a') {
90 printf("Test PASSED\n");
91 return PTS_PASS;
92 }
93
94 printf("mmap with MAP_SHARED failed to propagate change "
95 "into the child\n");
96 return PTS_FAIL;
97 case -1:
98 printf("Error at fork(): %s\n", strerror(errno));
99 return PTS_UNRESOLVED;
100
101 default:
102 waitpid(child, &exit_stat, WUNTRACED);
103
104 munmap(pa, size);
105
106 if (WIFEXITED(exit_stat)) {
107 return WEXITSTATUS(exit_stat);
108 } else {
109 printf("Child exited abnormally\n");
110 return PTS_UNRESOLVED;
111 }
112 }
113 }
114