msg.h revision 50477 
1/* $FreeBSD: head/sys/sys/msg.h 50477 1999-08-28 01:08:13Z peter $ */
2/*	$NetBSD: msg.h,v 1.4 1994/06/29 06:44:43 cgd Exp $	*/
3
4/*
5 * SVID compatible msg.h file
6 *
7 * Author:  Daniel Boulet
8 *
9 * Copyright 1993 Daniel Boulet and RTMX Inc.
10 *
11 * This system call was implemented by Daniel Boulet under contract from RTMX.
12 *
13 * Redistribution and use in source forms, with and without modification,
14 * are permitted provided that this entire comment appears intact.
15 *
16 * Redistribution in binary form may occur without any restrictions.
17 * Obviously, it would be nice if you gave credit where credit is due
18 * but requiring it would be too onerous.
19 *
20 * This software is provided ``AS IS'' without any warranties of any kind.
21 */
22
23#ifndef _SYS_MSG_H_
24#define _SYS_MSG_H_
25
26#include <sys/ipc.h>
27
28/*
29 * The MSG_NOERROR identifier value, the msqid_ds struct and the msg struct
30 * are as defined by the SV API Intel 386 Processor Supplement.
31 */
32
33#define MSG_NOERROR	010000		/* don't complain about too long msgs */
34
35struct msqid_ds {
36	struct	ipc_perm msg_perm;	/* msg queue permission bits */
37	struct	msg *msg_first;	/* first message in the queue */
38	struct	msg *msg_last;	/* last message in the queue */
39	u_long	msg_cbytes;	/* number of bytes in use on the queue */
40	u_long	msg_qnum;	/* number of msgs in the queue */
41	u_long	msg_qbytes;	/* max # of bytes on the queue */
42	pid_t	msg_lspid;	/* pid of last msgsnd() */
43	pid_t	msg_lrpid;	/* pid of last msgrcv() */
44	time_t	msg_stime;	/* time of last msgsnd() */
45	long	msg_pad1;
46	time_t	msg_rtime;	/* time of last msgrcv() */
47	long	msg_pad2;
48	time_t	msg_ctime;	/* time of last msgctl() */
49	long	msg_pad3;
50	long	msg_pad4[4];
51};
52
53struct msg {
54	struct	msg *msg_next;	/* next msg in the chain */
55	long	msg_type;	/* type of this message */
56    				/* >0 -> type of this message */
57    				/* 0 -> free header */
58	u_short	msg_ts;		/* size of this message */
59	short	msg_spot;	/* location of start of msg in buffer */
60};
61
62/*
63 * Structure describing a message.  The SVID doesn't suggest any
64 * particular name for this structure.  There is a reference in the
65 * msgop man page that reads "The structure mymsg is an example of what
66 * this user defined buffer might look like, and includes the following
67 * members:".  This sentence is followed by two lines equivalent
68 * to the mtype and mtext field declarations below.  It isn't clear
69 * if "mymsg" refers to the naem of the structure type or the name of an
70 * instance of the structure...
71 */
72struct mymsg {
73	long	mtype;		/* message type (+ve integer) */
74	char	mtext[1];	/* message body */
75};
76
77/*
78 * Based on the configuration parameters described in an SVR2 (yes, two)
79 * config(1m) man page.
80 *
81 * Each message is broken up and stored in segments that are msgssz bytes
82 * long.  For efficiency reasons, this should be a power of two.  Also,
83 * it doesn't make sense if it is less than 8 or greater than about 256.
84 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
85 * two between 8 and 1024 inclusive (and panic's if it isn't).
86 */
87struct msginfo {
88	int	msgmax,		/* max chars in a message */
89		msgmni,		/* max message queue identifiers */
90		msgmnb,		/* max chars in a queue */
91		msgtql,		/* max messages in system */
92		msgssz,		/* size of a message segment (see notes above) */
93		msgseg;		/* number of message segments */
94};
95#ifdef KERNEL
96extern struct msginfo	msginfo;
97
98#ifndef MSGSSZ
99#define MSGSSZ	8		/* Each segment must be 2^N long */
100#endif
101#ifndef MSGSEG
102#define MSGSEG	2048		/* must be less than 32767 */
103#endif
104#define MSGMAX	(MSGSSZ*MSGSEG)
105#ifndef MSGMNB
106#define MSGMNB	2048		/* max # of bytes in a queue */
107#endif
108#ifndef MSGMNI
109#define MSGMNI	40
110#endif
111#ifndef MSGTQL
112#define MSGTQL	40
113#endif
114
115/*
116 * macros to convert between msqid_ds's and msqid's.
117 * (specific to this implementation)
118 */
119#define MSQID(ix,ds)	((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
120#define MSQID_IX(id)	((id) & 0xffff)
121#define MSQID_SEQ(id)	(((id) >> 16) & 0xffff)
122
123/*
124 * The rest of this file is specific to this particular implementation.
125 */
126
127
128/*
129 * Stuff allocated in machdep.h
130 */
131struct msgmap {
132	short	next;		/* next segment in buffer */
133    				/* -1 -> available */
134    				/* 0..(MSGSEG-1) -> index of next segment */
135};
136
137extern char *msgpool;		/* MSGMAX byte long msg buffer pool */
138extern struct msgmap *msgmaps;	/* MSGSEG msgmap structures */
139extern struct msg *msghdrs;	/* MSGTQL msg headers */
140extern struct msqid_ds *msqids;	/* MSGMNI msqid_ds struct's */
141
142#define MSG_LOCKED	01000	/* Is this msqid_ds locked? */
143
144#endif /* KERNEL */
145
146#ifndef KERNEL
147#include <sys/cdefs.h>
148
149__BEGIN_DECLS
150int msgsys __P((int, ...));
151int msgctl __P((int, int, struct msqid_ds *));
152int msgget __P((key_t, int));
153int msgsnd __P((int, void *, size_t, int));
154int msgrcv __P((int, void*, size_t, long, int));
155__END_DECLS
156#endif /* !KERNEL */
157
158#endif /* !_SYS_MSG_H_ */
159