1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/* Copyright (C) 2002-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
static int
do_test (void)
{
size_t ps = sysconf (_SC_PAGESIZE);
char tmpfname[] = "/tmp/tst-rwlock12.XXXXXX";
char data[ps];
void *mem;
int fd;
pthread_mutex_t *m;
pthread_mutexattr_t ma;
pthread_rwlock_t *r;
pthread_rwlockattr_t ra;
pid_t pid;
int status = 0;
fd = mkstemp (tmpfname);
if (fd == -1)
{
printf ("cannot open temporary file: %m\n");
return 1;
}
/* Make sure it is always removed. */
unlink (tmpfname);
/* Create one page of data. */
memset (data, '\0', ps);
/* Write the data to the file. */
if (write (fd, data, ps) != (ssize_t) ps)
{
puts ("short write");
return 1;
}
mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (mem == MAP_FAILED)
{
printf ("mmap failed: %m\n");
return 1;
}
r = (pthread_rwlock_t *) (((uintptr_t) mem + __alignof (pthread_rwlock_t))
& ~(__alignof (pthread_rwlock_t) - 1));
/* The following assumes alignment for a mutex is at least as high
as that for a rwlock. Which is true in our case. */
m = (pthread_mutex_t *) (r + 1);
if (pthread_rwlockattr_init (&ra) != 0)
{
puts ("rwlockattr_init failed");
return 1;
}
if (pthread_rwlockattr_setpshared (&ra, PTHREAD_PROCESS_SHARED) != 0)
{
puts ("rwlockattr_setpshared failed");
return 1;
}
if (pthread_rwlock_init (r, &ra) != 0)
{
puts ("rwlock_init failed");
return 1;
}
if (pthread_mutexattr_init (&ma) != 0)
{
puts ("rwlockattr_init failed");
return 1;
}
if (pthread_mutexattr_setpshared (&ma, PTHREAD_PROCESS_SHARED) != 0)
{
puts ("mutexattr_setpshared failed");
return 1;
}
if (pthread_mutex_init (m, &ma) != 0)
{
puts ("mutex_init failed");
return 1;
}
/* Lock the mutex. */
if (pthread_mutex_lock (m) != 0)
{
puts ("mutex_lock failed");
return 1;
}
puts ("going to fork now");
pid = fork ();
if (pid == -1)
{
puts ("fork failed");
return 1;
}
else if (pid == 0)
{
/* Lock the mutex. */
if (pthread_mutex_lock (m) != 0)
{
puts ("child: mutex_lock failed");
return 1;
}
/* Try to get the rwlock. */
if (pthread_rwlock_trywrlock (r) == 0)
{
puts ("rwlock_trywrlock succeeded");
return 1;
}
/* Try again. */
struct timespec ts = { .tv_sec = 0, .tv_nsec = 500000000 };
int e = pthread_rwlock_timedwrlock (r, &ts);
if (e == 0)
{
puts ("rwlock_timedwrlock succeeded");
return 1;
}
if (e != ETIMEDOUT)
{
puts ("rwlock_timedwrlock didn't return ETIMEDOUT");
status = 1;
}
if (pthread_rwlock_tryrdlock (r) == 0)
{
puts ("rwlock_tryrdlock succeeded");
return 1;
}
e = pthread_rwlock_timedrdlock (r, &ts);
if (e == 0)
{
puts ("rwlock_timedrdlock succeeded");
return 1;
}
if (e != ETIMEDOUT)
{
puts ("rwlock_timedrdlock didn't return ETIMEDOUT");
status = 1;
}
}
else
{
/* Lock the rwlock for writing. */
if (pthread_rwlock_wrlock (r) != 0)
{
puts ("rwlock_wrlock failed");
kill (pid, SIGTERM);
return 1;
}
/* Allow the child to run. */
if (pthread_mutex_unlock (m) != 0)
{
puts ("mutex_unlock failed");
kill (pid, SIGTERM);
return 1;
}
/* Just wait for the child. */
if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
{
puts ("waitpid failed");
kill (pid, SIGTERM);
return 1;
}
}
return status;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
|
