1 /*
2 * Copyright (c) International Business Machines Corp., 2001
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 /*
20 * Test Description:
21 * Verify that, mmap() succeeds when used to map a file where size of the
22 * file is not a multiple of the page size, the memory area beyond the end
23 * of the file to the end of the page is accessible. Also, verify that
24 * this area is all zeroed and the modifications done to this area are
25 * not written to the file.
26 *
27 * Expected Result:
28 * mmap() should succeed returning the address of the mapped region.
29 * The memory area beyond the end of file to the end of page should be
30 * filled with zero.
31 * The changes beyond the end of file should not get written to the file.
32 *
33 * HISTORY
34 * 07/2001 Ported by Wayne Boyer
35 */
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <sys/types.h>
39 #include <errno.h>
40 #include <unistd.h>
41 #include <fcntl.h>
42 #include <string.h>
43 #include <signal.h>
44 #include <stdint.h>
45 #include <sys/stat.h>
46 #include <sys/mman.h>
47 #include <sys/shm.h>
48
49 #include "test.h"
50
51 #define TEMPFILE "mmapfile"
52
53 char *TCID = "mmap01";
54 int TST_TOTAL = 1;
55
56 static char *addr;
57 static char *dummy;
58 static size_t page_sz;
59 static size_t file_sz;
60 static int fildes;
61 static char cmd_buffer[BUFSIZ];
62
63 static void setup(void);
64 static void cleanup(void);
65
main(int ac,char ** av)66 int main(int ac, char **av)
67 {
68 int lc;
69
70 tst_parse_opts(ac, av, NULL, NULL);
71
72 setup();
73
74 for (lc = 0; TEST_LOOPING(lc); lc++) {
75
76 tst_count = 0;
77
78 /*
79 * Call mmap to map the temporary file beyond EOF
80 * with write access.
81 */
82 errno = 0;
83 addr = mmap(NULL, page_sz, PROT_READ | PROT_WRITE,
84 MAP_FILE | MAP_SHARED, fildes, 0);
85
86 /* Check for the return value of mmap() */
87 if (addr == MAP_FAILED) {
88 tst_resm(TFAIL | TERRNO, "mmap of %s failed", TEMPFILE);
89 continue;
90 }
91
92 /*
93 * Check if mapped memory area beyond EOF are
94 * zeros and changes beyond EOF are not written
95 * to file.
96 */
97 if (memcmp(&addr[file_sz], dummy, page_sz - file_sz)) {
98 tst_brkm(TFAIL, cleanup,
99 "mapped memory area contains invalid "
100 "data");
101 }
102
103 /*
104 * Initialize memory beyond file size
105 */
106 addr[file_sz] = 'X';
107 addr[file_sz + 1] = 'Y';
108 addr[file_sz + 2] = 'Z';
109
110 /*
111 * Synchronize the mapped memory region
112 * with the file.
113 */
114 if (msync(addr, page_sz, MS_SYNC) != 0) {
115 tst_brkm(TFAIL | TERRNO, cleanup,
116 "failed to synchronize mapped file");
117 }
118
119 /*
120 * Now, Search for the pattern 'XYZ' in the
121 * temporary file. The pattern should not be
122 * found and the return value should be 1.
123 */
124 if (system(cmd_buffer) != 0) {
125 tst_resm(TPASS,
126 "Functionality of mmap() successful");
127 } else {
128 tst_resm(TFAIL,
129 "Specified pattern found in file");
130 }
131
132 /* Clean up things in case we are looping */
133 /* Unmap the mapped memory */
134 if (munmap(addr, page_sz) != 0) {
135 tst_brkm(TFAIL | TERRNO, NULL, "munmap failed");
136 }
137 }
138
139 cleanup();
140 tst_exit();
141 }
142
setup(void)143 static void setup(void)
144 {
145 struct stat stat_buf;
146 char Path_name[PATH_MAX];
147 char write_buf[] = "hello world\n";
148
149 tst_sig(FORK, DEF_HANDLER, cleanup);
150
151 TEST_PAUSE;
152
153 tst_tmpdir();
154
155 /* Get the path of temporary file to be created */
156 if (getcwd(Path_name, sizeof(Path_name)) == NULL) {
157 tst_brkm(TFAIL | TERRNO, cleanup,
158 "getcwd failed to get current working directory");
159 }
160
161 /* Creat a temporary file used for mapping */
162 if ((fildes = open(TEMPFILE, O_RDWR | O_CREAT, 0666)) < 0) {
163 tst_brkm(TFAIL, cleanup, "opening %s failed", TEMPFILE);
164 }
165
166 /* Write some data into temporary file */
167 if (write(fildes, write_buf, strlen(write_buf)) != (long)strlen(write_buf)) {
168 tst_brkm(TFAIL, cleanup, "writing to %s", TEMPFILE);
169 }
170
171 /* Get the size of temporary file */
172 if (stat(TEMPFILE, &stat_buf) < 0) {
173 tst_brkm(TFAIL | TERRNO, cleanup, "stat of %s failed",
174 TEMPFILE);
175 }
176 file_sz = stat_buf.st_size;
177
178 page_sz = getpagesize();
179
180 /* Allocate and initialize dummy string of system page size bytes */
181 if ((dummy = calloc(page_sz, sizeof(char))) == NULL) {
182 tst_brkm(TFAIL, cleanup, "calloc failed (dummy)");
183 }
184
185 /* Create the command which will be executed in the test */
186 sprintf(cmd_buffer, "grep XYZ %s/%s > /dev/null", Path_name, TEMPFILE);
187 }
188
cleanup(void)189 static void cleanup(void)
190 {
191 close(fildes);
192 free(dummy);
193 tst_rmdir();
194 }
195