/*      $OpenBSD: msg.h,v 1.24 2024/10/27 22:08:25 jsg Exp $    */
/*      $NetBSD: msg.h,v 1.9 1996/02/09 18:25:18 christos 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 */

typedef unsigned long    msgqnum_t;
typedef unsigned long    msglen_t;

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];
};

#ifdef _KERNEL
#include <sys/queue.h>

struct msg {
        long             msg_type;
        size_t           msg_len;
        struct mbuf     *msg_data;

        TAILQ_ENTRY(msg)        msg_next;
};

struct que {
        struct msqid_ds msqid_ds;
        int             que_ix;         /* pseudo-index */
        int             que_flags;
        int             que_references;

        TAILQ_ENTRY(que)        que_next;
        TAILQ_HEAD(, msg) que_msgs;
};

/* for que_flags */
#define MSGQ_READERS    0x01
#define MSGQ_WRITERS    0x02
#define MSGQ_DYING      0x04

#define QREF(q) (q)->que_references++

#define QRELE(q) do {                                                   \
        if (--(q)->que_references == 0 && (q)->que_flags & MSGQ_DYING)  \
                wakeup_one(&(q)->que_references);                       \
} while (0)

/*
 * 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 SYSVMSG
extern struct msginfo   msginfo;
#endif

int sysctl_sysvmsg(int *, u_int, void *, size_t *);

struct msg_sysctl_info {
        struct msginfo msginfo;
        struct msqid_ds msgids[1];
};

#ifndef MSGSSZ
#define MSGSSZ  8               /* Each segment must be 2^N long */
#endif
#ifndef MSGSEG
#define MSGSEG  2048            /* must be less than 32767 */
#endif
#undef MSGMAX                   /* ALWAYS compute MSGMAX! */
#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

void msginit(void);
#else /* !_KERNEL */
__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);
__END_DECLS
#endif

#endif /* !_SYS_MSG_H_ */