/* $FreeBSD: src/sys/sys/msg.h,v 1.10.2.1 2000/08/04 22:31:10 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/cdefs.h>
#include <sys/ipc.h>
#include <machine/stdint.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 */

typedef unsigned long   msglen_t;
typedef unsigned long   msgqnum_t;

#ifndef _PID_T_DECLARED
typedef __pid_t         pid_t;
#define _PID_T_DECLARED
#endif

#ifndef _SIZE_T_DECLARED
typedef __size_t        size_t;
#define _SIZE_T_DECLARED
#endif

#ifndef _SSIZE_T_DECLARED
typedef __ssize_t       ssize_t;
#define _SSIZE_T_DECLARED
#endif

#ifndef _TIME_T_DECLARED
typedef __time_t        time_t;
#define _TIME_T_DECLARED
#endif

/*!!! In the kernel implementation, both msg_first and msg_last
 * have 'struct msg*' type.
 * In the userland implementation, a pointer to a msg is useless
 * because each message queue is mapped at different addresses in
 * the process space address so my choice was to use indexes.
 */
struct msg;

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. */
        msglen_t msg_cbytes;    /* number of bytes in use on the queue */
        msgqnum_t msg_qnum;     /* number of msgs in the queue */
        msglen_t 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];
};

#if __BSD_VISIBLE
/*
 * 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 */
};
#endif

#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)

/*
 * 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 */
};
#endif

#ifdef _KERNEL
extern struct msginfo   msginfo;
#else
__BEGIN_DECLS
int     msgctl(int, int, struct msqid_ds *);
int     msgget(key_t, int);
int     msgsnd(int, const void *, size_t, int);
int     msgrcv(int, void *, size_t, long, int); /* XXX should return ssize_t */
__END_DECLS
#endif

#endif /* !_SYS_MSG_H_ */