1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2020 Linaro Limited. All rights reserved.
4 * Author: Viresh Kumar <viresh.kumar@linaro.org>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Test to check if fd set bits are cleared by select().
11 *
12 * [Algorithm]
13 * - Check that writefds flag is cleared on full pipe
14 * - Check that readfds flag is cleared on empty pipe
15 */
16
17 #include <unistd.h>
18 #include <errno.h>
19 #include <sys/time.h>
20 #include <sys/types.h>
21 #include <fcntl.h>
22 #include "select_var.h"
23
24 static fd_set readfds_pipe, writefds_pipe;
25 static int fd_empty[2], fd_full[2];
26
27 static struct tcases {
28 int *fd;
29 fd_set *readfds;
30 fd_set *writefds;
31 char *desc;
32 } tests[] = {
33 {&fd_empty[0], &readfds_pipe, NULL, "No data to read"},
34 {&fd_full[1], NULL, &writefds_pipe, "No space to write"},
35 };
36
run(unsigned int n)37 static void run(unsigned int n)
38 {
39 struct tcases *tc = &tests[n];
40 struct timeval timeout = {.tv_sec = 0, .tv_usec = 1000};
41
42 FD_SET(fd_empty[0], &readfds_pipe);
43 FD_SET(fd_full[1], &writefds_pipe);
44
45 TEST(do_select(*tc->fd + 1, tc->readfds, tc->writefds, NULL, &timeout));
46
47 if (TST_RET) {
48 tst_res(TFAIL, "%s: select() should have timed out", tc->desc);
49 return;
50 }
51
52 if ((tc->readfds && FD_ISSET(*tc->fd, tc->readfds)) ||
53 (tc->writefds && FD_ISSET(*tc->fd, tc->writefds))) {
54 tst_res(TFAIL, "%s: select() didn't clear the fd set", tc->desc);
55 return;
56 }
57
58 tst_res(TPASS, "%s: select() cleared the fd set", tc->desc);
59 }
60
setup(void)61 static void setup(void)
62 {
63 int buf = 0;
64
65 select_info();
66
67 SAFE_PIPE(fd_empty);
68 FD_ZERO(&readfds_pipe);
69
70 SAFE_PIPE2(fd_full, O_NONBLOCK);
71 FD_ZERO(&writefds_pipe);
72
73 /* Make the write buffer full for fd_full */
74 do {
75 TEST(write(fd_full[1], &buf, sizeof(buf)));
76 } while (TST_RET != -1);
77
78 if (TST_ERR != EAGAIN)
79 tst_res(TFAIL | TTERRNO, "write() failed with unexpected error");
80 }
81
82 static struct tst_test test = {
83 .test = run,
84 .tcnt = ARRAY_SIZE(tests),
85 .test_variants = TEST_VARIANTS,
86 .setup = setup,
87 .needs_tmpdir = 1,
88 };
89