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 
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 
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)) != 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 
189 static void cleanup(void)
190 {
191 	close(fildes);
192 	free(dummy);
193 	tst_rmdir();
194 }
195