1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2001
4 * 07/2001 Ported by John George
5 * Copyright (c) 2017 Fujitsu Ltd.
6 * 04/2017 Modified by Jinhui Huang
7 */
8
9 /*
10 * DESCRIPTION
11 * Testcase to check that write(2) doesn't corrupt a file when it fails
12 *
13 * ALGORITHM
14 * Create a file for writing, write 100 bytes to it. Then make write(2)
15 * fail with some erroneous parameter, close the fd. Then reopen the
16 * file in RDONLY mode, and read the contents of the file. Compare the
17 * buffers, to see whether they are same.
18 */
19
20 #include <stdio.h>
21 #include <errno.h>
22 #include "tst_test.h"
23
24 static char *bad_addr;
25 static char wbuf[BUFSIZ], rbuf[BUFSIZ];
26 static int fd;
27
verify_write(void)28 static void verify_write(void)
29 {
30 fd = SAFE_CREAT("testfile", 0644);
31
32 SAFE_WRITE(SAFE_WRITE_ALL, fd, wbuf, 100);
33
34 if (write(fd, bad_addr, 100) != -1) {
35 tst_res(TFAIL, "write() failed to fail");
36 SAFE_CLOSE(fd);
37 return;
38 }
39
40 SAFE_CLOSE(fd);
41
42 fd = SAFE_OPEN("testfile", O_RDONLY);
43
44 memset(rbuf, 0, BUFSIZ);
45
46 SAFE_READ(0, fd, rbuf, 100);
47
48 if (memcmp(wbuf, rbuf, 100) == 0)
49 tst_res(TPASS, "failure of write() did not corrupt the file");
50 else
51 tst_res(TFAIL, "failure of write() corrupted the file");
52
53 SAFE_CLOSE(fd);
54 }
55
setup(void)56 static void setup(void)
57 {
58 bad_addr = SAFE_MMAP(0, 1, PROT_NONE,
59 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
60
61 memset(wbuf, '0', 100);
62 }
63
cleanup(void)64 static void cleanup(void)
65 {
66 if (fd > 0)
67 SAFE_CLOSE(fd);
68 }
69
70 static struct tst_test test = {
71 .test_all = verify_write,
72 .setup = setup,
73 .cleanup = cleanup,
74 .needs_tmpdir = 1,
75 };
76