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76a50749 UD |
1 | /* Copyright (C) 2002 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, write to the Free | |
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
18 | 02111-1307 USA. */ | |
19 | ||
20 | #include <errno.h> | |
21 | #include <pthread.h> | |
22 | #include <stdint.h> | |
23 | #include <stdio.h> | |
24 | #include <stdlib.h> | |
25 | #include <string.h> | |
26 | #include <unistd.h> | |
27 | #include <sys/mman.h> | |
28 | #include <sys/wait.h> | |
29 | ||
30 | ||
31 | int | |
32 | main (void) | |
33 | { | |
34 | size_t ps = sysconf (_SC_PAGESIZE); | |
35 | char tmpfname[] = "/tmp/tst-spin2.XXXXXX"; | |
36 | char data[ps]; | |
37 | void *mem; | |
38 | int fd; | |
39 | pthread_spinlock_t *s; | |
40 | pid_t pid; | |
41 | char *p; | |
42 | int err; | |
43 | ||
44 | fd = mkstemp (tmpfname); | |
45 | if (fd == -1) | |
46 | { | |
47 | printf ("cannot open temporary file: %m\n"); | |
48 | exit (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) != ps) | |
59 | { | |
60 | puts ("short write"); | |
61 | exit (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 | exit (1); | |
69 | } | |
70 | ||
71 | s = (pthread_spinlock_t *) (((uintptr_t) mem | |
72 | + __alignof (pthread_spinlock_t)) | |
73 | & ~(__alignof (pthread_spinlock_t) - 1)); | |
74 | p = (char *) (s + 1); | |
75 | ||
76 | if (pthread_spin_init (s, PTHREAD_PROCESS_SHARED) != 0) | |
77 | { | |
78 | puts ("spin_init failed"); | |
79 | exit (1); | |
80 | } | |
81 | ||
82 | if (pthread_spin_lock (s) != 0) | |
83 | { | |
84 | puts ("spin_lock failed"); | |
85 | exit (1); | |
86 | } | |
87 | ||
88 | err = pthread_spin_trylock (s); | |
89 | if (err == 0) | |
90 | { | |
f78deea6 | 91 | puts ("1st spin_trylock succeeded"); |
76a50749 UD |
92 | exit (1); |
93 | } | |
94 | else if (err != EBUSY) | |
95 | { | |
f78deea6 UD |
96 | puts ("1st spin_trylock didn't return EBUSY"); |
97 | exit (1); | |
98 | } | |
99 | ||
100 | err = pthread_spin_unlock (s); | |
101 | if (err != 0) | |
102 | { | |
103 | puts ("parent: spin_unlock failed"); | |
104 | exit (1); | |
105 | } | |
106 | ||
107 | err = pthread_spin_trylock (s); | |
108 | if (err != 0) | |
109 | { | |
110 | puts ("2nd spin_trylock failed"); | |
76a50749 UD |
111 | exit (1); |
112 | } | |
113 | ||
114 | *p = 0; | |
115 | ||
116 | puts ("going to fork now"); | |
117 | pid = fork (); | |
118 | if (pid == -1) | |
119 | { | |
120 | puts ("fork failed"); | |
121 | exit (1); | |
122 | } | |
123 | else if (pid == 0) | |
124 | { | |
125 | /* Play some lock ping-pong. It's our turn to unlock first. */ | |
126 | if ((*p)++ != 0) | |
127 | { | |
128 | puts ("child: *p != 0"); | |
129 | exit (1); | |
130 | } | |
131 | ||
132 | if (pthread_spin_unlock (s) != 0) | |
133 | { | |
134 | puts ("child: 1st spin_unlock failed"); | |
135 | exit (1); | |
136 | } | |
137 | ||
138 | puts ("child done"); | |
139 | } | |
140 | else | |
141 | { | |
142 | if (pthread_spin_lock (s) != 0) | |
143 | { | |
144 | puts ("parent: 2nd spin_lock failed"); | |
145 | exit (1); | |
146 | } | |
147 | ||
148 | puts ("waiting for child"); | |
149 | ||
150 | waitpid (pid, NULL, 0); | |
151 | ||
152 | puts ("parent done"); | |
153 | } | |
154 | ||
155 | exit (0); | |
156 | } |