1 /* Copyright (C) 2002-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <errno.h>
19 #include <pthread.h>
20 #include <stdint.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include <sys/mman.h>
26 #include <sys/wait.h>
27
28
29 static int
30 do_test (void)
31 {
32 size_t ps = sysconf (_SC_PAGESIZE);
33 char tmpfname[] = "/tmp/tst-rwlock4.XXXXXX";
34 char data[ps];
35 void *mem;
36 int fd;
37 pthread_rwlock_t *r;
38 pthread_rwlockattr_t a;
39 pid_t pid;
40 char *p;
41 int err;
42 int s;
43
44 fd = mkstemp (tmpfname);
45 if (fd == -1)
46 {
47 printf ("cannot open temporary file: %m\n");
48 return 1;
49 }
50
51 /* Make sure it is always removed. */
52 unlink (tmpfname);
53
54 /* Create one page of data. */
55 memset (data, '\0', ps);
56
57 /* Write the data to the file. */
58 if (write (fd, data, ps) != (ssize_t) ps)
59 {
60 puts ("short write");
61 return 1;
62 }
63
64 mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
65 if (mem == MAP_FAILED)
66 {
67 printf ("mmap failed: %m\n");
68 return 1;
69 }
70
71 r = (pthread_rwlock_t *) (((uintptr_t) mem + __alignof (pthread_rwlock_t))
72 & ~(__alignof (pthread_rwlock_t) - 1));
73 p = (char *) (r + 1);
74
75 if (pthread_rwlockattr_init (&a) != 0)
76 {
77 puts ("rwlockattr_init failed");
78 return 1;
79 }
80
81 if (pthread_rwlockattr_getpshared (&a, &s) != 0)
82 {
83 puts ("1st rwlockattr_getpshared failed");
84 return 1;
85 }
86
87 if (s != PTHREAD_PROCESS_PRIVATE)
88 {
89 puts ("default pshared value wrong");
90 return 1;
91 }
92
93 if (pthread_rwlockattr_setpshared (&a, PTHREAD_PROCESS_SHARED) != 0)
94 {
95 puts ("rwlockattr_setpshared failed");
96 return 1;
97 }
98
99 if (pthread_rwlockattr_getpshared (&a, &s) != 0)
100 {
101 puts ("2nd rwlockattr_getpshared failed");
102 return 1;
103 }
104
105 if (s != PTHREAD_PROCESS_SHARED)
106 {
107 puts ("pshared value after setpshared call wrong");
108 return 1;
109 }
110
111 if (pthread_rwlock_init (r, &a) != 0)
112 {
113 puts ("rwlock_init failed");
114 return 1;
115 }
116
117 if (pthread_rwlock_rdlock (r) != 0)
118 {
119 puts ("rwlock_rdlock failed");
120 return 1;
121 }
122
123 if (pthread_rwlockattr_destroy (&a) != 0)
124 {
125 puts ("rwlockattr_destroy failed");
126 return 1;
127 }
128
129 err = pthread_rwlock_trywrlock (r);
130 if (err == 0)
131 {
132 puts ("rwlock_trywrlock succeeded");
133 return 1;
134 }
135 else if (err != EBUSY)
136 {
137 puts ("rwlock_trywrlock didn't return EBUSY");
138 return 1;
139 }
140
141 *p = 0;
142
143 puts ("going to fork now");
144 pid = fork ();
145 if (pid == -1)
146 {
147 puts ("fork failed");
148 return 1;
149 }
150 else if (pid == 0)
151 {
152 /* Play some lock ping-pong. It's our turn to unlock first. */
153 if ((*p)++ != 0)
154 {
155 puts ("child: *p != 0");
156 return 1;
157 }
158
159 if (pthread_rwlock_unlock (r) != 0)
160 {
161 puts ("child: 1st rwlock_unlock failed");
162 return 1;
163 }
164
165 puts ("child done");
166 }
167 else
168 {
169 if (pthread_rwlock_wrlock (r) != 0)
170 {
171 puts ("parent: rwlock_wrlock failed");
172 return 1;
173 }
174
175 if (*p != 1)
176 {
177 puts ("*p != 1");
178 return 1;
179 }
180
181 puts ("parent done");
182 }
183
184 return 0;
185 }
186
187 #define TEST_FUNCTION do_test ()
188 #include "../test-skeleton.c"