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
|
/* Test the interaction of fork and robust mutexes.
Copyright (C) 2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <stdbool.h>
#include <stdio.h>
#include <support/check.h>
#include <support/test-driver.h>
#include <support/xthread.h>
#include <support/xunistd.h>
#include <sys/mman.h>
/* Data shared between processes. */
struct shared
{
pthread_mutex_t parent_mutex;
pthread_mutex_t child_mutex;
};
/* These flags control which mutex settings are enabled in the parent
and child (separately). */
enum mutex_bits
{
mutex_pshared = 1,
mutex_robust = 2,
mutex_pi = 4,
mutex_check = 8,
/* All bits combined. */
mutex_all_bits = 15,
};
static void
mutex_init (pthread_mutex_t *mutex, int bits)
{
pthread_mutexattr_t attr;
xpthread_mutexattr_init (&attr);
if (bits & mutex_pshared)
xpthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED);
if (bits & mutex_robust)
xpthread_mutexattr_setrobust (&attr, PTHREAD_MUTEX_ROBUST);
if (bits & mutex_pi)
xpthread_mutexattr_setprotocol (&attr, PTHREAD_PRIO_INHERIT);
if (bits & mutex_check)
xpthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK);
xpthread_mutex_init (mutex, &attr);
xpthread_mutexattr_destroy (&attr);
}
static void
one_test (int parent_bits, int child_bits, int nonshared_bits,
bool lock_nonshared, bool lock_child)
{
struct shared *shared = xmmap (NULL, sizeof (*shared),
PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_SHARED, -1);
mutex_init (&shared->parent_mutex, parent_bits);
mutex_init (&shared->child_mutex, child_bits);
/* Acquire the parent mutex in the parent. */
xpthread_mutex_lock (&shared->parent_mutex);
pthread_mutex_t nonshared_mutex;
mutex_init (&nonshared_mutex, nonshared_bits);
if (lock_nonshared)
xpthread_mutex_lock (&nonshared_mutex);
pid_t pid = xfork ();
if (pid == 0)
{
/* Child process. */
if (lock_child)
xpthread_mutex_lock (&shared->child_mutex);
else
xmunmap (shared, sizeof (*shared));
if (lock_nonshared)
/* Reinitialize the non-shared mutex if it was locked in the
parent. */
mutex_init (&nonshared_mutex, nonshared_bits);
xpthread_mutex_lock (&nonshared_mutex);
/* For robust mutexes, the _exit call will perform the unlock
instead. */
if (lock_child && !(child_bits & mutex_robust))
xpthread_mutex_unlock (&shared->child_mutex);
_exit (0);
}
/* Parent process. */
{
int status;
xwaitpid (pid, &status, 0);
TEST_VERIFY (status == 0);
}
if (parent_bits & mutex_check)
/* Test for expected self-deadlock. This is only possible to
detect if the mutex is error-checking. */
TEST_VERIFY_EXIT (pthread_mutex_lock (&shared->parent_mutex) == EDEADLK);
pid = xfork ();
if (pid == 0)
{
/* Child process. We can perform some checks only if we are
dealing with process-shared mutexes. */
if (parent_bits & mutex_pshared)
/* It must not be possible to acquire the parent mutex.
NB: This check touches a mutex which has been acquired in
the parent at fork time, so it might be deemed undefined
behavior, pending the resolution of Austin Groups issue
1112. */
TEST_VERIFY_EXIT (pthread_mutex_trylock (&shared->parent_mutex)
== EBUSY);
if (lock_child && (child_bits & mutex_robust))
{
if (!(child_bits & mutex_pshared))
/* No further tests possible. */
_exit (0);
TEST_VERIFY_EXIT (pthread_mutex_lock (&shared->child_mutex)
== EOWNERDEAD);
xpthread_mutex_consistent (&shared->child_mutex);
}
else
/* We did not acquire the lock in the first child process, or
we unlocked the mutex again because the mutex is not a
robust mutex. */
xpthread_mutex_lock (&shared->child_mutex);
xpthread_mutex_unlock (&shared->child_mutex);
_exit (0);
}
/* Parent process. */
{
int status;
xwaitpid (pid, &status, 0);
TEST_VERIFY (status == 0);
}
if (lock_nonshared)
xpthread_mutex_unlock (&nonshared_mutex);
xpthread_mutex_unlock (&shared->parent_mutex);
xpthread_mutex_destroy (&shared->parent_mutex);
xpthread_mutex_destroy (&shared->child_mutex);
xpthread_mutex_destroy (&nonshared_mutex);
xmunmap (shared, sizeof (*shared));
}
static int
do_test (void)
{
for (int parent_bits = 0; parent_bits <= mutex_all_bits; ++parent_bits)
for (int child_bits = 0; child_bits <= mutex_all_bits; ++child_bits)
for (int nonshared_bits = 0; nonshared_bits <= mutex_all_bits;
++nonshared_bits)
for (int lock_nonshared = 0; lock_nonshared < 2; ++lock_nonshared)
for (int lock_child = 0; lock_child < 2; ++lock_child)
{
if (test_verbose)
printf ("info: parent_bits=0x%x child_bits=0x%x"
" nonshared_bits=0x%x%s%s\n",
parent_bits, child_bits, nonshared_bits,
lock_nonshared ? " lock_nonshared" : "",
lock_child ? " lock_child" : "");
one_test (parent_bits, child_bits, nonshared_bits,
lock_nonshared, lock_child);
}
return 0;
}
#include <support/test-driver.c>
|
