Initial import of t_shmat.
[pcca-tests.git] / mqueue.h / t_mq_select.c
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1/*
2 * Copyright (c) 2009, Stathis Kamperis
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
17 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
18 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
20 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
22 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
24 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
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28#include <assert.h>
29#include <errno.h>
30#include <fcntl.h>
31#include <mqueue.h>
32#include <stdio.h>
33#include <stdlib.h>
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34#include <string.h>
35#include <unistd.h> /* fork() */
18fd27d7 36
322a3d9c 37#define MQNAME "/t_mq_select"
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38
39int main(void)
40{
41 const char msg[] = "Child says hello to parent";
42 struct timeval abs_timeout;
43 mqd_t md;
44 fd_set ms;
45 pid_t pid;
46
47 /* Create a message queue for write only with default parameters. */
01345d7d 48 md = mq_open(MQNAME, O_CREAT | O_EXCL | O_RDWR, 0777, NULL);
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49 assert(md != -1);
50
51 /* Initialize descriptor set to null set. */
52 FD_ZERO(&ms);
53
54 /* Add message queue descriptor to set. */
55 FD_SET(md, &ms);
5cae5d63 56 assert(FD_ISSET(md, &ms)); /* Just a sanity check. */
18fd27d7 57
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58 /* Wait for 2 seconds. */
59 abs_timeout.tv_sec = 2;
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60 abs_timeout.tv_usec = 0;
61
62 /* This should time out. */
63 assert(select(md + 1, &ms, NULL, NULL, &abs_timeout) == 0);
64
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65 FD_SET(md, &ms);
66 assert(FD_ISSET(md, &ms)); /* Just a sanity check. */
67
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68 /* Fork. */
69 pid = fork();
70 assert(pid != -1);
71
72 if (pid == 0) {
73 /* We are inside the child. */
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74 /* Wait for parent to block on select(). */
75 sleep(1);
18fd27d7 76
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77 /* Send message. */
78 assert(mq_send(md, msg, sizeof(msg), /* priority */ 0) != -1);
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79 } else {
80 /* We are inside the parent. */
01345d7d 81 assert(select(md + 1, &ms, NULL, NULL, &abs_timeout) > 0);
5cae5d63 82 assert(FD_ISSET(md, &ms));
18fd27d7 83
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84 char msg_recvd[8192]; /* Implementation defined. */
85 assert(mq_receive(md, msg_recvd, sizeof(msg_recvd), NULL) != -1);
86 assert(strcmp(msg_recvd, msg) == 0);
18fd27d7 87
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88 /* Remove message queue descriptor from the set. */
89 FD_CLR(md, &ms);
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90
91 /*
92 * At this point we know for sure that the child has completed,
93 * otherwise we would still be blocked by select().
94 */
95
96 /* Disassociate with message queue. */
2c16f5cb 97 assert(mq_close(md) != -1);
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98
99 /* Remove the message queue from the system. */
2c16f5cb 100 assert(mq_unlink(MQNAME) != -1);
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101
102 printf("passed\n");
103 }
104
105 return (EXIT_SUCCESS);
106}