1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Copyright (c) Matthew Wilcox for Hewlett Packard 2003
3 * Copyright (c) Linux Test Project, 2007-2018
4 * Author: Matthew Wilcox
5 */
6
7 /*\
8 * [Description]
9 *
10 * Test verifies that flock locks held on one file descriptor conflict with
11 * flock locks held on a different file descriptor.
12 *
13 * The process opens two file descriptors on the same file. It acquires
14 * an exclusive flock on the first descriptor, checks that attempting to
15 * acquire an flock on the second descriptor fails. Then it removes the
16 * first descriptor's lock and attempts to acquire an exclusive lock on
17 * the second descriptor.
18 */
19
20 #include <errno.h>
21 #include <sys/file.h>
22
23 #include "tst_test.h"
24
verify_flock(void)25 static void verify_flock(void)
26 {
27 int fd1, fd2;
28
29 fd1 = SAFE_OPEN("testfile", O_RDWR);
30 TEST(flock(fd1, LOCK_EX | LOCK_NB));
31 if (TST_RET != 0)
32 tst_res(TFAIL | TTERRNO, "First attempt to flock() failed");
33 else
34 tst_res(TPASS, "First attempt to flock() passed");
35
36 fd2 = SAFE_OPEN("testfile", O_RDWR);
37 TEST(flock(fd2, LOCK_EX | LOCK_NB));
38 if (TST_RET == -1)
39 tst_res(TPASS | TTERRNO, "Second attempt to flock() denied");
40 else
41 tst_res(TFAIL, "Second attempt to flock() succeeded!");
42
43 TEST(flock(fd1, LOCK_UN));
44 if (TST_RET != 0)
45 tst_res(TFAIL | TTERRNO, "Failed to unlock fd1");
46 else
47 tst_res(TPASS, "Unlocked fd1");
48
49 TEST(flock(fd2, LOCK_EX | LOCK_NB));
50 if (TST_RET != 0)
51 tst_res(TFAIL | TTERRNO, "Third attempt to flock() denied!");
52 else
53 tst_res(TPASS, "Third attempt to flock() succeeded");
54
55 SAFE_CLOSE(fd1);
56 SAFE_CLOSE(fd2);
57 }
58
setup(void)59 static void setup(void)
60 {
61 int fd;
62
63 fd = SAFE_OPEN("testfile", O_CREAT | O_TRUNC | O_RDWR, 0666);
64 SAFE_CLOSE(fd);
65 }
66
67 static struct tst_test test = {
68 .test_all = verify_flock,
69 .needs_tmpdir = 1,
70 .setup = setup,
71 };
72