mqueues: Port POSIX message queues from NetBSD.
[dragonfly.git] / sys / sys / mqueue.h
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f2df0f7c 1/* $NetBSD: mqueue.h,v 1.7 2009/04/11 15:47:34 christos Exp $ */
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3/*
4 * Copyright (c) 2007, Mindaugas Rasiukevicius <rmind at NetBSD org>
5 * All rights reserved.
6 *
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7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
984263bc 15 *
f2df0f7c 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
f2df0f7c 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
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27 */
28
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29#ifndef _SYS_MQUEUE_H_
30#define _SYS_MQUEUE_H_
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32/* Maximal number of mqueue descriptors, that process could open */
33#define MQ_OPEN_MAX 512
984263bc 34
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35/* Maximal priority of the message */
36#define MQ_PRIO_MAX 32
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37
38struct mq_attr {
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39 long mq_flags; /* Flags of message queue */
40 long mq_maxmsg; /* Maximum number of messages */
41 long mq_msgsize; /* Maximum size of the message */
42 long mq_curmsgs; /* Count of the queued messages */
43};
44
45/* Internal kernel data */
46/*#ifdef _KERNEL*/
47#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
48
49/*#include <sys/condvar.h>*/
50/*#include <sys/mutex.h>*/
51#include <sys/types.h>
52#include <sys/lock.h>
53#include <sys/types.h>
54#include <sys/queue.h>
55#include <sys/selinfo.h>
56#include <sys/types.h>
57
58/*
59 * Flags below are used in mq_flags for internal
60 * purposes, this is appropriate according to POSIX.
61 */
62
63/* Message queue is unlinking */
64#define MQ_UNLINK 0x10000000
65/* There are receive-waiters */
66#define MQ_RECEIVE 0x20000000
67
68/* Maximal length of mqueue name */
69#define MQ_NAMELEN (NAME_MAX + 1)
70
71/* Default size of the message */
72#define MQ_DEF_MSGSIZE 1024
73
74/* Size/bits and index of reserved queue */
75#define MQ_PQSIZE 32
76#define MQ_PQRESQ 0
77
78/* Structure of the message queue */
79struct mqueue {
80 char mq_name[MQ_NAMELEN];
81 struct lock mq_mtx;
82 int mq_send_cv; /* Condition variables for tsleep() */
83 int mq_recv_cv;
84 struct mq_attr mq_attrib;
85 /* Notification */
86 struct selinfo mq_rsel;
87 struct selinfo mq_wsel;
88 struct sigevent mq_sig_notify;
89 struct proc * mq_notify_proc;
90 /* Permissions */
91 mode_t mq_mode;
92 uid_t mq_euid;
93 gid_t mq_egid;
94 /*
95 * Reference counter, heads of the message queue
96 *
97 * Every message queue has `MQ_PQSIZE' priority queues that guarantee
98 * constant-time insertion of messages. If `mq_prio_max' is increased
99 * via sysctl, then the reserved queue (MQ_PQRESQ) is used which
100 * performs linear insertion.
101 */
102 u_int mq_refcnt;
103 TAILQ_HEAD(, mq_msg) mq_head[1 + MQ_PQSIZE];
104 uint32_t mq_bitmap;
105 /* Entry of the global list */
106 LIST_ENTRY(mqueue) mq_list;
107 struct timespec mq_atime;
108 struct timespec mq_mtime;
109 struct timespec mq_btime;
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110};
111
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112/* Structure of the message */
113struct mq_msg {
114 TAILQ_ENTRY(mq_msg) msg_queue;
115 size_t msg_len;
116 u_int msg_prio;
117 int8_t msg_ptr[1];
118};
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120/* Prototypes */
121void mqueue_sysinit(void);
122void mqueue_print_list(void (*pr)(const char *, ...));
123int abstimeout2timo(struct timespec *, int *);
124int mq_send1(struct lwp *, mqd_t, const char *, size_t, unsigned, struct timespec *);
125int mq_receive1(struct lwp *, mqd_t, void *, size_t, unsigned *, struct timespec *,
126 ssize_t *);
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f2df0f7c 128#endif /* _KERNEL || _KERNEL_STRUCTURES */
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f2df0f7c 130#endif /* _SYS_MQUEUE_H_ */
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