pipe_fstat_bug_test.c revision 309662 
1/*
2Copyright (C) 2004 Michael J. Silbersack. All rights reserved.
3
4Redistribution and use in source and binary forms, with or without
5modification, are permitted provided that the following conditions
6are met:
71. Redistributions of source code must retain the above copyright
8   notice, this list of conditions and the following disclaimer.
92. Redistributions in binary form must reproduce the above copyright
10   notice, this list of conditions and the following disclaimer in the
11   documentation and/or other materials provided with the distribution.
12
13THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23SUCH DAMAGE.
24*/
25
26#include <sys/types.h>
27#include <sys/stat.h>
28#include <sys/wait.h>
29#include <sys/event.h>
30#include <assert.h>
31#include <err.h>
32#include <errno.h>
33#include <inttypes.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <unistd.h>
37
38/*
39 * $FreeBSD: stable/10/tests/sys/kern/pipe/pipe_fstat_bug_test.c 309662 2016-12-07 00:57:15Z ngie $
40 * The goal of this program is to see if fstat reports the correct
41 * data count for a pipe.  Prior to revision 1.172 of sys_pipe.c,
42 * 0 would be returned once the pipe entered direct write mode.
43 *
44 * Linux (2.6) always returns zero, so it's not a valuable platform
45 * for comparison.
46 */
47
48int
49main(void)
50{
51	char buffer[32768], buffer2[32768], go[] = "go", go2[] = "go2";
52	int desc[2], ipc_coord[2];
53	struct kevent event, ke;
54	ssize_t error;
55	int successes = 0;
56	struct stat status;
57	pid_t new_pid;
58	int kq;
59
60	error = pipe(desc);
61	if (error == -1)
62		err(1, "Couldn't allocate data pipe");
63
64	error = pipe(ipc_coord);
65	if (error == -1)
66		err(1, "Couldn't allocate IPC coordination pipe");
67
68	new_pid = fork();
69	assert(new_pid != -1);
70
71	close(new_pid == 0 ? desc[0] : desc[1]);
72
73#define	SYNC_R(i, _buf) do {	\
74	int _error = errno; \
75	warnx("%d: waiting for synchronization", __LINE__); \
76	if (read(ipc_coord[i], &_buf, sizeof(_buf)) != sizeof(_buf)) \
77		err(1, "failed to synchronize (%s)", (i == 0 ? "parent" : "child")); \
78	errno = _error; \
79	} while(0)
80
81#define	SYNC_W(i, _buf) do {	\
82	int _error = errno; \
83	warnx("%d: sending synchronization", __LINE__); \
84	if (write(ipc_coord[i], &_buf, sizeof(_buf)) != sizeof(_buf)) \
85		err(1, "failed to synchronize (%s)", (i == 0 ? "child" : "parent")); \
86	errno = _error; \
87	} while(0)
88
89#define	WRITE(s) do { 							\
90	ssize_t _size; 							\
91	if ((_size = write(desc[1], &buffer, s)) != s)			\
92		warn("short write; wrote %zd, expected %d", _size, s);	\
93	} while(0)
94
95	if (new_pid == 0) {
96
97		SYNC_R(0, go);
98		WRITE(145);
99		SYNC_W(0, go2);
100
101		SYNC_R(0, go);
102		WRITE(2048);
103		SYNC_W(0, go2);
104
105		SYNC_R(0, go);
106		WRITE(4096);
107		SYNC_W(0, go2);
108
109		SYNC_R(0, go);
110		WRITE(8191);
111		SYNC_W(0, go2);
112
113		SYNC_R(0, go);
114		SYNC_W(0, go2); /* XXX: why is this required? */
115		WRITE(8192);
116		SYNC_W(0, go2);
117
118		close(ipc_coord[0]);
119		close(ipc_coord[1]);
120
121		_exit(0);
122	}
123
124	kq = kqueue();
125	if (kq == -1)
126		_exit(1);
127
128	EV_SET(&ke, desc[0], EVFILT_READ, EV_ADD, 0, 0, NULL);
129
130	/* Attach event to the kqueue. */
131	if (kevent(kq, &ke, 1, NULL, 0, NULL) != 0)
132		_exit(2);
133
134	while (successes < 5) {
135		SYNC_W(1, go);
136		SYNC_R(1, go2);
137
138		/* Ensure data is available to read */
139		if (kevent(kq, NULL, 0, &event, 1, NULL) != 1)
140			_exit(3);
141
142		fstat(desc[0], &status);
143		error = read(desc[0], &buffer2, sizeof(buffer2));
144
145		if (status.st_size != error)
146			err(1, "FAILURE: stat size %jd read size %zd",
147			    (intmax_t)status.st_size, error);
148		if (error > 0) {
149			printf("SUCCESS at stat size %jd read size %zd\n",
150			    (intmax_t)status.st_size, error);
151			successes++;
152		}
153	}
154
155	exit(0);
156}
157