1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2001
4 * 07/2001 Ported by Wayne Boyer
5 * 07/2002 Limited forking and split "infinite forks" testcase to fork12.c by
6 * Nate Straz
7 * Copyright (c) 2021 Xie Ziyao <[email protected]>
8 */
9
10 /*\
11 * [Description]
12 *
13 * Check that all children inherit parent's file descriptor.
14 *
15 * Parent opens a file and forks children. Each child reads a byte and checks
16 * that the value is correct. Parent checks that correct number of bytes was
17 * consumed from the file.
18 */
19
20 #include <stdlib.h>
21
22 #include "tst_test.h"
23
24 #define NFORKS 100
25 #define TESTFILE "testfile_fork07"
26
27 static int fd;
28 static char buf;
29
run(void)30 static void run(void)
31 {
32 int ret, i;
33
34 fd = SAFE_OPEN(TESTFILE, O_RDONLY);
35 for (i = 0; i < NFORKS; ++i) {
36 if (!SAFE_FORK()) {
37 SAFE_READ(1, fd, &buf, 1);
38 if (buf != 'a')
39 tst_res(TFAIL, "%6d: read '%c' instead of 'a'",
40 getpid(), buf);
41 exit(0);
42 }
43 }
44 tst_reap_children();
45
46 ret = read(fd, &buf, 1);
47 if (ret == 0)
48 tst_res(TPASS, "read the end of file correctly");
49 else
50 tst_res(TFAIL, "read() returns %d, expected 0", ret);
51
52 SAFE_CLOSE(fd);
53 }
54
setup(void)55 static void setup(void)
56 {
57 tst_fill_file(TESTFILE, 'a', NFORKS, 1);
58 }
59
cleanup(void)60 static void cleanup(void)
61 {
62 if (fd > 0)
63 SAFE_CLOSE(fd);
64 }
65
66 static struct tst_test test = {
67 .forks_child = 1,
68 .needs_tmpdir = 1,
69 .cleanup = cleanup,
70 .setup = setup,
71 .test_all = run,
72 };
73