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
24static char *bad_addr;
25static char wbuf[BUFSIZ], rbuf[BUFSIZ];
26static int fd;
27
28static 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
56static 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
64static void cleanup(void)
65{
66	if (fd > 0)
67		SAFE_CLOSE(fd);
68}
69
70static struct tst_test test = {
71	.test_all = verify_write,
72	.setup = setup,
73	.cleanup = cleanup,
74	.needs_tmpdir = 1,
75};
76