1 /*
2 * Copyright (c) 2017 Red Hat, Inc.
3 * 01/02/2003 Port to LTP avenkat@us.ibm.com
4 * 06/30/2001 Port to Linux nsharoff@us.ibm.com
5 *
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19 /*
20 * Mmap parts of a file, and then write to the file causing single
21 * write requests to jump back and forth between mmaped io and regular io.
22 */
23
24 #define _GNU_SOURCE
25 #include <stdlib.h>
26 #include "tst_test.h"
27 #include "tst_safe_macros.h"
28
29 #define NUM_PAGES (192)
30 #define TEST_FILE "mmapstress04-testfile"
31
32 static int page_size;
33 static unsigned char *mmap_area;
34
setup(void)35 static void setup(void)
36 {
37 page_size = getpagesize();
38
39 /*
40 * Pick large enough area, PROT_NONE doesn't matter,
41 * because we remap it later.
42 */
43 mmap_area = SAFE_MMAP(NULL, page_size * NUM_PAGES, PROT_NONE,
44 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
45 }
46
write_fully(int fd,void * buf,int len)47 static void write_fully(int fd, void *buf, int len)
48 {
49 int ret;
50
51 do {
52 ret = SAFE_WRITE(0, fd, buf, len);
53 buf += ret;
54 len -= ret;
55 } while (len > 0);
56 }
57
mmapstress04(void)58 static void mmapstress04(void)
59 {
60 int i, j, rofd, rwfd;
61 char *buf;
62 int mapped_pages = 0;
63
64 if (tst_fill_file(TEST_FILE, 'b', page_size, 1))
65 tst_brk(TBROK | TERRNO, "fill_file");
66
67 rofd = SAFE_OPEN(TEST_FILE, O_RDONLY | O_CREAT, 0777);
68 /*
69 * Assuming disk blocks are 8k, and logical pages are 4k, there are
70 * two maps per block. In order to test mapping at the beginning and
71 * ends of the block, mapping the whole block, or none of the block
72 * with different mappings on preceding and following blocks, each
73 * 3 blocks with 6 pages can be thought of as a binary number from 0 to
74 * 64 with a bit set for mapped or cleared for unmapped. This number
75 * is represented by i. The value j is used to look at the bits of i
76 * and decided to map the page or not.
77 * NOTE: None of the above assumptions are critical.
78 */
79 for (i = 0; i < 64; i++) {
80 for (j = 0; j < 6; j++) {
81 off_t mapoff;
82
83 if (!(i & (1 << j)))
84 continue;
85
86 mapoff = page_size * (off_t)(6 * i + j);
87 SAFE_MMAP(mmap_area + page_size * mapped_pages++,
88 page_size, PROT_READ,
89 MAP_FILE | MAP_PRIVATE | MAP_FIXED,
90 rofd, mapoff);
91 }
92 }
93 SAFE_CLOSE(rofd);
94
95 /* write out 6 pages of stuff into each of the 64 six page sections */
96 rwfd = SAFE_OPEN(TEST_FILE, O_RDWR);
97 buf = SAFE_MALLOC(page_size);
98 memset(buf, 'a', page_size);
99 for (i = 0; i < 6 * 64; i++)
100 write_fully(rwfd, buf, page_size);
101 free(buf);
102 SAFE_CLOSE(rwfd);
103
104 /*
105 * Just finished scribbling all over interwoven mmapped and unmapped
106 * regions. Check the data.
107 */
108 for (i = 0; i < mapped_pages * page_size; i++) {
109 unsigned char val = *(mmap_area + i);
110
111 if (val != 'a') {
112 tst_res(TFAIL, "unexpected value in map, "
113 "i=%d,val=0x%x", i, val);
114 goto done;
115 }
116 }
117 tst_res(TPASS, "blocks have expected data");
118 done:
119 SAFE_UNLINK(TEST_FILE);
120 }
121
122 static struct tst_test test = {
123 .needs_tmpdir = 1,
124 .test_all = mmapstress04,
125 .setup = setup,
126 };
127