text: /* $Id: msg.h,v 1.8 1997/02/22 09:45:36 peter Exp $ */
  /*	$NetBSD: msg.h,v 1.4 1994/06/29 06:44:43 cgd Exp $	*/
  
  /*
   * SVID compatible msg.h file
   *
   * Author:  Daniel Boulet
   *
   * Copyright 1993 Daniel Boulet and RTMX Inc.
   *
   * This system call was implemented by Daniel Boulet under contract from RTMX.
   *
   * Redistribution and use in source forms, with and without modification,
   * are permitted provided that this entire comment appears intact.
   *
   * Redistribution in binary form may occur without any restrictions.
   * Obviously, it would be nice if you gave credit where credit is due
   * but requiring it would be too onerous.
   *
   * This software is provided ``AS IS'' without any warranties of any kind.
   */
  
  #ifndef _SYS_MSG_H_
  #define _SYS_MSG_H_
  
  #include <sys/ipc.h>
  
  /*
   * The MSG_NOERROR identifier value, the msqid_ds struct and the msg struct
   * are as defined by the SV API Intel 386 Processor Supplement.
   */
  
  #define MSG_NOERROR	010000		/* don't complain about too long msgs */
  
  struct msqid_ds {
  	struct	ipc_perm msg_perm;	/* msg queue permission bits */
  	struct	msg *msg_first;	/* first message in the queue */
  	struct	msg *msg_last;	/* last message in the queue */
  	u_long	msg_cbytes;	/* number of bytes in use on the queue */
  	u_long	msg_qnum;	/* number of msgs in the queue */
  	u_long	msg_qbytes;	/* max # of bytes on the queue */
  	pid_t	msg_lspid;	/* pid of last msgsnd() */
  	pid_t	msg_lrpid;	/* pid of last msgrcv() */
  	time_t	msg_stime;	/* time of last msgsnd() */
  	long	msg_pad1;
  	time_t	msg_rtime;	/* time of last msgrcv() */
  	long	msg_pad2;
  	time_t	msg_ctime;	/* time of last msgctl() */
  	long	msg_pad3;
  	long	msg_pad4[4];
  };
  
  struct msg {
  	struct	msg *msg_next;	/* next msg in the chain */
  	long	msg_type;	/* type of this message */
      				/* >0 -> type of this message */
      				/* 0 -> free header */
  	u_short	msg_ts;		/* size of this message */
  	short	msg_spot;	/* location of start of msg in buffer */
  };
  
  /*
   * Structure describing a message.  The SVID doesn't suggest any
   * particular name for this structure.  There is a reference in the
   * msgop man page that reads "The structure mymsg is an example of what
   * this user defined buffer might look like, and includes the following
   * members:".  This sentence is followed by two lines equivalent
   * to the mtype and mtext field declarations below.  It isn't clear
   * if "mymsg" refers to the naem of the structure type or the name of an
   * instance of the structure...
   */
  struct mymsg {
  	long	mtype;		/* message type (+ve integer) */
  	char	mtext[1];	/* message body */
  };
  
  /*
   * Based on the configuration parameters described in an SVR2 (yes, two)
   * config(1m) man page.
   *
   * Each message is broken up and stored in segments that are msgssz bytes
   * long.  For efficiency reasons, this should be a power of two.  Also,
   * it doesn't make sense if it is less than 8 or greater than about 256.
   * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
   * two between 8 and 1024 inclusive (and panic's if it isn't).
   */
  struct msginfo {
  	int	msgmax,		/* max chars in a message */
  		msgmni,		/* max message queue identifiers */
  		msgmnb,		/* max chars in a queue */
  		msgtql,		/* max messages in system */
  		msgssz,		/* size of a message segment (see notes above) */
  		msgseg;		/* number of message segments */
  };
  #ifdef KERNEL
  extern struct msginfo	msginfo;
  
  #ifndef MSGSSZ
  #define MSGSSZ	8		/* Each segment must be 2^N long */
  #endif
  #ifndef MSGSEG
  #define MSGSEG	2048		/* must be less than 32767 */
  #endif
  #define MSGMAX	(MSGSSZ*MSGSEG)
  #ifndef MSGMNB
  #define MSGMNB	2048		/* max # of bytes in a queue */
  #endif
  #ifndef MSGMNI
  #define MSGMNI	40
  #endif
  #ifndef MSGTQL
  #define MSGTQL	40
  #endif
  
  /*
   * macros to convert between msqid_ds's and msqid's.
   * (specific to this implementation)
   */
  #define MSQID(ix,ds)	((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
  #define MSQID_IX(id)	((id) & 0xffff)
  #define MSQID_SEQ(id)	(((id) >> 16) & 0xffff)
  
  /*
   * The rest of this file is specific to this particular implementation.
   */
  
  
  /*
   * Stuff allocated in machdep.h
   */
  struct msgmap {
  	short	next;		/* next segment in buffer */
      				/* -1 -> available */
      				/* 0..(MSGSEG-1) -> index of next segment */
  };
  
  extern char *msgpool;		/* MSGMAX byte long msg buffer pool */
  extern struct msgmap *msgmaps;	/* MSGSEG msgmap structures */
  extern struct msg *msghdrs;	/* MSGTQL msg headers */
  extern struct msqid_ds *msqids;	/* MSGMNI msqid_ds struct's */
  
  #define MSG_LOCKED	01000	/* Is this msqid_ds locked? */
  
  #endif /* KERNEL */
  
  #ifndef KERNEL
  #include <sys/cdefs.h>
  
  __BEGIN_DECLS
  int msgsys __P((int, ...));
  int msgctl __P((int, int, struct msqid_ds *));
  int msgget __P((key_t, int));
  int msgsnd __P((int, void *, size_t, int));
  int msgrcv __P((int, void*, size_t, long, int));
  __END_DECLS
  #endif /* !KERNEL */
  
  #endif /* !_SYS_MSG_H_ */
  