msgbuf.h revision 331722 
1/*-
2 * Copyright (c) 1981, 1984, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)msgbuf.h	8.1 (Berkeley) 6/2/93
30 * $FreeBSD: stable/11/sys/sys/msgbuf.h 331722 2018-03-29 02:50:57Z eadler $
31 */
32
33#ifndef _SYS_MSGBUF_H_
34#define	_SYS_MSGBUF_H_
35
36#include <sys/lock.h>
37#include <sys/mutex.h>
38
39struct msgbuf {
40	char	   *msg_ptr;		/* pointer to buffer */
41#define	MSG_MAGIC	0x063062
42	u_int	   msg_magic;
43	u_int	   msg_size;		/* size of buffer area */
44	u_int	   msg_wseq;		/* write sequence number */
45	u_int	   msg_rseq;		/* read sequence number */
46	u_int	   msg_cksum;		/* checksum of contents */
47	u_int	   msg_seqmod;		/* range for sequence numbers */
48	int	   msg_lastpri;		/* saved priority value */
49	u_int      msg_flags;
50#define MSGBUF_NEEDNL	0x01	/* set when newline needed */
51	struct mtx msg_lock;		/* mutex to protect the buffer */
52};
53
54/* Normalise a sequence number or a difference between sequence numbers. */
55#define	MSGBUF_SEQNORM(mbp, seq)	(((seq) + (mbp)->msg_seqmod) % \
56    (mbp)->msg_seqmod)
57#define	MSGBUF_SEQ_TO_POS(mbp, seq)	((seq) % (mbp)->msg_size)
58/* Subtract sequence numbers.  Note that only positive values result. */
59#define	MSGBUF_SEQSUB(mbp, seq1, seq2)	(MSGBUF_SEQNORM((mbp), (seq1) - (seq2)))
60
61#ifdef _KERNEL
62extern int	msgbufsize;
63extern int	msgbuftrigger;
64extern struct	msgbuf *msgbufp;
65extern struct	mtx msgbuf_lock;
66
67void	msgbufinit(void *ptr, int size);
68void	msgbuf_addchar(struct msgbuf *mbp, int c);
69void	msgbuf_addstr(struct msgbuf *mbp, int pri, char *str, int filter_cr);
70void	msgbuf_clear(struct msgbuf *mbp);
71void	msgbuf_copy(struct msgbuf *src, struct msgbuf *dst);
72int	msgbuf_getbytes(struct msgbuf *mbp, char *buf, int buflen);
73int	msgbuf_getchar(struct msgbuf *mbp);
74int	msgbuf_getcount(struct msgbuf *mbp);
75void	msgbuf_init(struct msgbuf *mbp, void *ptr, int size);
76int	msgbuf_peekbytes(struct msgbuf *mbp, char *buf, int buflen,
77	    u_int *seqp);
78void	msgbuf_reinit(struct msgbuf *mbp, void *ptr, int size);
79
80#ifndef MSGBUF_SIZE
81#define	MSGBUF_SIZE	(32768 * 3)
82#endif
83#endif /* KERNEL */
84
85#endif /* !_SYS_MSGBUF_H_ */
86