1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2021 FUJITSU LIMITED. All rights reserved.
4 * Author: Dai Shili <daisl.fnst@fujitsu.com>
5 */
6
7/*\
8 * [Description]
9 *
10 * Test the write() system call with O_APPEND.
11 *
12 * The full description of O_APPEND is in open(2) man-pages:
13 * The file is opened in append mode.  Before each write(2), the
14 * file offset is positioned at the end of the file, as if with lseek(2).
15 * The modification of the file offset and the write operation are
16 * performed as a single atomic step.
17 *
18 * Writing 2k data to the file, close it and reopen it with O_APPEND.
19 * Verify that the file size is 3k and offset is moved to the end of the file.
20 */
21
22#include <stdlib.h>
23#include <inttypes.h>
24#include "tst_test.h"
25#include "tst_safe_prw.h"
26
27#define K1              1024
28#define K2              (K1 * 2)
29#define K3              (K1 * 3)
30#define DATA_FILE       "write06_file"
31
32static int fd = -1;
33static char *write_buf[2];
34
35static void verify_write(void)
36{
37	off_t off;
38	struct stat statbuf;
39
40	fd = SAFE_OPEN(DATA_FILE, O_RDWR | O_CREAT | O_TRUNC, 0666);
41	SAFE_WRITE(SAFE_WRITE_ALL, fd, write_buf[0], K2);
42	SAFE_CLOSE(fd);
43
44	fd = SAFE_OPEN(DATA_FILE, O_RDWR | O_APPEND);
45	SAFE_FSTAT(fd, &statbuf);
46	if (statbuf.st_size != K2)
47		tst_res(TFAIL, "file size is %ld != K2", statbuf.st_size);
48
49	off = SAFE_LSEEK(fd, K1, SEEK_SET);
50	if (off != K1)
51		tst_brk(TBROK, "Failed to seek to K1");
52
53	SAFE_WRITE(SAFE_WRITE_ALL, fd, write_buf[1], K1);
54
55	off = SAFE_LSEEK(fd, 0, SEEK_CUR);
56	if (off != K3)
57		tst_res(TFAIL, "Wrong offset after write %zu expected %u", off, K3);
58	else
59		tst_res(TPASS, "Offset is correct after write %zu", off);
60
61	SAFE_FSTAT(fd, &statbuf);
62	if (statbuf.st_size != K3)
63		tst_res(TFAIL, "Wrong file size after append %zu expected %u", statbuf.st_size, K3);
64	else
65		tst_res(TPASS, "Correct file size after append %u", K3);
66
67	SAFE_CLOSE(fd);
68}
69
70static void setup(void)
71{
72	memset(write_buf[0], 0, K2);
73	memset(write_buf[1], 1, K1);
74}
75
76static void cleanup(void)
77{
78	if (fd != -1)
79		SAFE_CLOSE(fd);
80
81	SAFE_UNLINK(DATA_FILE);
82}
83
84static struct tst_test test = {
85	.needs_tmpdir = 1,
86	.setup = setup,
87	.cleanup = cleanup,
88	.test_all = verify_write,
89	.bufs = (struct tst_buffers[]) {
90		{&write_buf[0], .size = K2},
91		{&write_buf[1], .size = K1},
92		{}
93	}
94};
95