1 /*
2 * Copyright (c) International Business Machines Corp., 2001
3 * 07/2001 Ported by John George
4 * Copyright (c) 2017 Fujitsu Ltd.
5 * 04/2017 Modified by Jinhui Huang
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /*
23 * DESCRIPTION
24 * Testcase to check that write(2) doesn't corrupt a file when it fails
25 *
26 * ALGORITHM
27 * Create a file for writing, write 100 bytes to it. Then make write(2)
28 * fail with some erroneous parameter, close the fd. Then reopen the
29 * file in RDONLY mode, and read the contents of the file. Compare the
30 * buffers, to see whether they are same.
31 */
32
33 #include <stdio.h>
34 #include <errno.h>
35 #include "tst_test.h"
36
37 static char *bad_addr;
38 static char wbuf[BUFSIZ], rbuf[BUFSIZ];
39 static int fd;
40
verify_write(void)41 static void verify_write(void)
42 {
43 fd = SAFE_CREAT("testfile", 0644);
44
45 SAFE_WRITE(1, fd, wbuf, 100);
46
47 if (write(fd, bad_addr, 100) != -1) {
48 tst_res(TFAIL, "write() failed to fail");
49 SAFE_CLOSE(fd);
50 return;
51 }
52
53 SAFE_CLOSE(fd);
54
55 fd = SAFE_OPEN("testfile", O_RDONLY);
56
57 memset(rbuf, 0, BUFSIZ);
58
59 SAFE_READ(0, fd, rbuf, 100);
60
61 if (memcmp(wbuf, rbuf, 100) == 0)
62 tst_res(TPASS, "failure of write() did not corrupt the file");
63 else
64 tst_res(TFAIL, "failure of write() corrupted the file");
65
66 SAFE_CLOSE(fd);
67 }
68
setup(void)69 static void setup(void)
70 {
71 bad_addr = SAFE_MMAP(0, 1, PROT_NONE,
72 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
73
74 memset(wbuf, '0', 100);
75 }
76
cleanup(void)77 static void cleanup(void)
78 {
79 if (fd > 0)
80 SAFE_CLOSE(fd);
81 }
82
83 static struct tst_test test = {
84 .test_all = verify_write,
85 .setup = setup,
86 .cleanup = cleanup,
87 .needs_tmpdir = 1,
88 };
89