1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2020 Francis Laniel. All rights reserved.
4 * Author: Francis Laniel <[email protected]>
5 *
6 * Test Description:
7 * This Program tests getting and setting the pipe size.
8 * It also tests what happen when you write to a full pipe depending on whether
9 * O_NONBLOCK is set or not.
10 */
11 #define _GNU_SOURCE
12 #include <stdlib.h>
13 #include <features.h>
14 #include <unistd.h>
15 #include <stdio.h>
16 #include "lapi/fcntl.h"
17 #include "tst_test.h"
18 #include "pgsize_helpers.h"
19
20 static int fds[2];
21 static int flags;
22
test_pipe2(void)23 static void test_pipe2(void)
24 {
25 int ret;
26 pid_t pid;
27
28 /*
29 * This ensures parent process is still in non-block mode when
30 * using -i parameter. Subquent writes hould return -1 and errno
31 * set to either EAGAIN or EWOULDBLOCK because pipe is already full.
32 */
33 SAFE_FCNTL(fds[1], F_SETFL, flags | O_NONBLOCK);
34 ret = write(fds[1], "x", 1);
35 if (ret == -1) {
36 if (errno == EAGAIN)
37 tst_res(TPASS | TERRNO, "write failed as expected");
38 else
39 tst_brk(TFAIL | TERRNO, "write failed expected EAGAIN but got");
40 } else {
41 tst_res(TFAIL, "write() succeeded unexpectedly");
42 }
43
44 pid = SAFE_FORK();
45 if (!pid) {
46 SAFE_FCNTL(fds[1], F_SETFL, flags & ~O_NONBLOCK);
47 SAFE_WRITE(SAFE_WRITE_ALL, fds[1], "x", 1);
48 }
49
50 if (TST_PROCESS_STATE_WAIT(pid, 'S', 1000) < 0)
51 tst_res(TFAIL, "Child process is not blocked");
52 else
53 tst_res(TPASS, "Child process is blocked");
54
55 SAFE_KILL(pid, SIGKILL);
56 SAFE_WAIT(NULL);
57 }
58
setup(void)59 static void setup(void)
60 {
61 int page_size, pipe_size;
62 char *write_buffer;
63
64 SAFE_PIPE2(fds, O_NONBLOCK);
65 page_size = kernel_page_size();
66
67 flags = SAFE_FCNTL(fds[1], F_GETFL);
68 if (!(flags & O_NONBLOCK))
69 tst_brk(TCONF, "O_NONBLOCK flag must be set");
70 /*
71 * A pipe has two file descriptors.
72 * But in the kernel these two file descriptors point to the same pipe.
73 * So setting size from first file handle set size for the pipe.
74 */
75 SAFE_FCNTL(fds[0], F_SETPIPE_SZ, 0);
76
77 /*
78 * So getting size from the second file descriptor return the size of
79 * the pipe which was changed before with first file descriptor.
80 */
81 pipe_size = SAFE_FCNTL(fds[1], F_GETPIPE_SZ);
82 if (pipe_size != page_size)
83 tst_res(TFAIL, "Pipe size (%d) must be page size (%d)",
84 pipe_size, page_size);
85
86 write_buffer = SAFE_MALLOC(pipe_size);
87 memset(write_buffer, 'x', pipe_size);
88 SAFE_WRITE(SAFE_WRITE_ALL, fds[1], write_buffer, pipe_size);
89 free(write_buffer);
90 }
91
cleanup(void)92 static void cleanup(void)
93 {
94 if (fds[0] > 0)
95 SAFE_CLOSE(fds[0]);
96 if (fds[1] > 0)
97 SAFE_CLOSE(fds[1]);
98 }
99
100 static struct tst_test test = {
101 .test_all = test_pipe2,
102 .setup = setup,
103 .cleanup = cleanup,
104 .forks_child = 1,
105 };
106