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1/* Copyright (C) 2002-2019 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, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <semaphore.h>
21#include <stdint.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <unistd.h>
26#include <sys/mman.h>
27#include <sys/wait.h>
28
29
30int
31do_test (void)
32{
33 size_t ps = sysconf (_SC_PAGESIZE);
34 char tmpfname[] = "/tmp/tst-sem3.XXXXXX";
35 char data[ps];
36 void *mem;
37 int fd;
38 sem_t *s;
39 pid_t pid;
40 char *p;
41
42 fd = mkstemp (tmpfname);
43 if (fd == -1)
44 {
45 printf ("cannot open temporary file: %m\n");
46 return 1;
47 }
48
49 /* Make sure it is always removed. */
50 unlink (tmpfname);
51
52 /* Create one page of data. */
53 memset (data, '\0', ps);
54
55 /* Write the data to the file. */
56 if (write (fd, data, ps) != (ssize_t) ps)
57 {
58 puts ("short write");
59 return 1;
60 }
61
62 mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
63 if (mem == MAP_FAILED)
64 {
65 printf ("mmap failed: %m\n");
66 return 1;
67 }
68
69 s = (sem_t *) (((uintptr_t) mem + __alignof (sem_t))
70 & ~(__alignof (sem_t) - 1));
71 p = (char *) (s + 1);
72
73 if (sem_init (s, 1, 1) == -1)
74 {
75 puts ("init failed");
76 return 1;
77 }
78
79 if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
80 {
81 puts ("1st wait failed");
82 return 1;
83 }
84
85 errno = 0;
86 if (TEMP_FAILURE_RETRY (sem_trywait (s)) != -1)
87 {
88 puts ("trywait succeeded");
89 return 1;
90 }
91 else if (errno != EAGAIN)
92 {
93 puts ("trywait didn't return EAGAIN");
94 return 1;
95 }
96
97 *p = 0;
98
99 puts ("going to fork now");
100 pid = fork ();
101 if (pid == -1)
102 {
103 puts ("fork failed");
104 return 1;
105 }
106 else if (pid == 0)
107 {
108 /* Play some lock ping-pong. It's our turn to unlock first. */
109 if ((*p)++ != 0)
110 {
111 puts ("child: *p != 0");
112 return 1;
113 }
114
115 if (sem_post (s) == -1)
116 {
117 puts ("child: 1st post failed");
118 return 1;
119 }
120
121 puts ("child done");
122 }
123 else
124 {
125 if (TEMP_FAILURE_RETRY (sem_wait (s)) == -1)
126 {
127 printf ("parent: 2nd wait failed: %m\n");
128 return 1;
129 }
130
131 if (*p != 1)
132 {
133 puts ("*p != 1");
134 return 1;
135 }
136
137 puts ("parent done");
138 }
139
140 return 0;
141}
142
143#define TEST_FUNCTION do_test ()
144#include "../test-skeleton.c"
145

Warning: That file was not part of the compilation database. It may have many parsing errors.