pipe - pre-MP work, change indexing to circular FIFO rindex/windex.
[dragonfly.git] / sys / sys / pipe.h
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1/*
2 * Copyright (c) 1996 John S. Dyson
3 * 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 immediately at the beginning of the file, without modification,
10 * this list of conditions, and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Absolutely no warranty of function or purpose is made by the author
15 * John S. Dyson.
16 * 4. This work was done expressly for inclusion into FreeBSD. Other use
17 * is allowed if this notation is included.
18 * 5. Modifications may be freely made to this file if the above conditions
19 * are met.
20 *
21 * $FreeBSD: src/sys/sys/pipe.h,v 1.16 1999/12/29 04:24:45 peter Exp $
9183fa5b 22 * $DragonFly: src/sys/sys/pipe.h,v 1.10 2006/06/10 20:00:17 dillon Exp $
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23 */
24
25#ifndef _SYS_PIPE_H_
26#define _SYS_PIPE_H_
27
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28#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
29
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30#ifndef _SYS_TYPES_H_
31#include <sys/types.h>
32#endif
33#ifndef _SYS_TIME_H_
984263bc 34#include <sys/time.h> /* for struct timespec */
1bd40720 35#endif
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36#ifndef _SYS_SELINFO_H_
37#include <sys/selinfo.h> /* for struct selinfo */
984263bc 38#endif
1bd40720 39#ifndef _SYS_XIO_H_
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40#include <sys/xio.h> /* for struct xio */
41#endif
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42#ifndef _MACHINE_PARAM_H_
43#include <machine/param.h> /* for PAGE_SIZE */
44#endif
24712b90 45
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46/*
47 * Pipe buffer size, keep moderate in value, pipes take kva space.
08593aa1 48 * Must be a multiple of PAGE_SIZE.
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49 */
50#ifndef PIPE_SIZE
51#define PIPE_SIZE 16384
52#endif
53
54#ifndef BIG_PIPE_SIZE
55#define BIG_PIPE_SIZE (64*1024)
56#endif
57
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58#if PIPE_SIZE < PAGE_SIZE
59#error "PIPE_SIZE is too small for this architecture"
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60#endif
61
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62/*
63 * Pipe buffer information.
64 * Separate in, out, cnt are used to simplify calculations.
65 * Buffered write is active when the buffer.cnt field is set.
66 */
67struct pipebuf {
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68 u_int rindex; /* FIFO read index */
69 u_int windex; /* FIFO write index */
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70 u_int size; /* size of buffer */
71 caddr_t buffer; /* kva of buffer */
fc7d5181 72 struct vm_object *object; /* VM object containing buffer */
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73};
74
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75/*
76 * Bits in pipe_state.
77 */
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78#define PIPE_ASYNC 0x0004 /* Async? I/O */
79#define PIPE_WANTR 0x0008 /* Reader wants some characters */
80#define PIPE_WANTW 0x0010 /* Writer wants space to put characters */
81#define PIPE_WANT 0x0020 /* Pipe is wanted to be run-down */
82#define PIPE_SEL 0x0040 /* Pipe has a select active */
83#define PIPE_EOF 0x0080 /* Pipe is in EOF condition */
84#define PIPE_LOCK 0x0100 /* Process has exclusive access to pts/data */
85#define PIPE_LWANT 0x0200 /* Process wants exclusive access to pts/data */
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86
87/*
88 * Per-pipe data structure.
89 * Two of these are linked together to produce bi-directional pipes.
90 */
91struct pipe {
92 struct pipebuf pipe_buffer; /* data storage */
8100156a 93 vm_offset_t pipe_kva; /* kva mapping (testing only) */
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94 struct selinfo pipe_sel; /* for compat with select */
95 struct timespec pipe_atime; /* time of last access */
96 struct timespec pipe_mtime; /* time of last modify */
97 struct timespec pipe_ctime; /* time of status change */
98 struct sigio *pipe_sigio; /* information for async I/O */
99 struct pipe *pipe_peer; /* link with other direction */
100 u_int pipe_state; /* pipe status info */
101 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
102};
103
03d6a592 104#endif /* _KERNEL || _KERNEL_STRUCTURES */
984263bc 105#endif /* !_SYS_PIPE_H_ */