1/* $NetBSD: pipe.h,v 1.33 2016/01/22 23:38:45 dholland Exp $ */
2
3/*
4 * Copyright (c) 1996 John S. Dyson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice immediately at the beginning of the file, without modification,
12 * this list of conditions, and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Absolutely no warranty of function or purpose is made by the author
17 * John S. Dyson.
18 * 4. This work was done expressly for inclusion into FreeBSD. Other use
19 * is allowed if this notation is included.
20 * 5. Modifications may be freely made to this file if the above conditions
21 * are met.
22 *
23 * $FreeBSD: src/sys/sys/pipe.h,v 1.18 2002/02/27 07:35:59 alfred Exp $
24 */
25
26#ifndef _SYS_PIPE_H_
27#define _SYS_PIPE_H_
28
29#include <sys/selinfo.h> /* for struct selinfo */
30#include <sys/time.h> /* for struct timespec */
31
32#include <uvm/uvm_extern.h>
33
34/*
35 * Pipe buffer size, keep moderate in value, pipes take kva space.
36 */
37#ifndef PIPE_SIZE
38#define PIPE_SIZE 16384
39#endif
40
41#ifndef BIG_PIPE_SIZE
42#define BIG_PIPE_SIZE (4*PIPE_SIZE)
43#endif
44
45/*
46 * Maximum size of kva for direct write transfer. If the amount
47 * of data in buffer is larger, it would be transferred in chunks of this
48 * size. This kva memory is freed after use if amount of pipe kva memory
49 * is bigger than limitpipekva.
50 */
51#ifndef PIPE_DIRECT_CHUNK
52#define PIPE_DIRECT_CHUNK (1*1024*1024)
53#endif
54
55/*
56 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
57 * than PIPE_BUF.
58 */
59#ifndef PIPE_MINDIRECT
60#define PIPE_MINDIRECT 8192
61#endif
62
63/*
64 * Pipe buffer information.
65 * Separate in, out, cnt are used to simplify calculations.
66 * Buffered write is active when the buffer.cnt field is set.
67 */
68struct pipebuf {
69 size_t cnt; /* number of chars currently in buffer */
70 u_int in; /* in pointer */
71 u_int out; /* out pointer */
72 size_t size; /* size of buffer */
73 void * buffer; /* kva of buffer */
74};
75
76/*
77 * Information to support direct transfers between processes for pipes.
78 */
79struct pipemapping {
80 vaddr_t kva; /* kernel virtual address */
81 vsize_t cnt; /* number of chars in buffer */
82 voff_t pos; /* current position within page */
83 int npages; /* how many pages allocated */
84 struct vm_page **pgs; /* pointers to the pages */
85 u_int egen; /* emap generation number */
86};
87
88/*
89 * Bits in pipe_state.
90 */
91#define PIPE_ASYNC 0x001 /* Async I/O */
92#define PIPE_EOF 0x010 /* Pipe is in EOF condition */
93#define PIPE_SIGNALR 0x020 /* Do selwakeup() on read(2) */
94#define PIPE_DIRECTW 0x040 /* Pipe in direct write mode setup */
95#define PIPE_DIRECTR 0x080 /* Pipe direct read request (setup complete) */
96#define PIPE_LOCKFL 0x100 /* Process has exclusive access to
97 pointers/data. */
98#define PIPE_LWANT 0x200 /* Process wants exclusive access to
99 pointers/data. */
100#define PIPE_RESTART 0x400 /* Return ERESTART to blocked syscalls */
101
102/*
103 * Per-pipe data structure.
104 * Two of these are linked together to produce bi-directional pipes.
105 */
106struct pipe {
107 kmutex_t *pipe_lock; /* pipe mutex */
108 kcondvar_t pipe_rcv; /* cv for readers */
109 kcondvar_t pipe_wcv; /* cv for writers */
110 kcondvar_t pipe_draincv; /* cv for close */
111 kcondvar_t pipe_lkcv; /* locking */
112 struct pipebuf pipe_buffer; /* data storage */
113 struct pipemapping pipe_map; /* pipe mapping for direct I/O */
114 struct selinfo pipe_sel; /* for compat with select */
115 struct timespec pipe_atime; /* time of last access */
116 struct timespec pipe_mtime; /* time of last modify */
117 struct timespec pipe_btime; /* time of creation */
118 pid_t pipe_pgid; /* process group for sigio */
119 struct pipe *pipe_peer; /* link with other direction */
120 u_int pipe_state; /* pipe status info */
121 int pipe_busy; /* busy flag, to handle rundown */
122 vaddr_t pipe_kmem; /* preallocated PIPE_SIZE buffer */
123};
124
125/*
126 * KERN_PIPE subtypes
127 */
128#define KERN_PIPE_MAXKVASZ 1 /* maximum kva size */
129#define KERN_PIPE_LIMITKVA 2 /* */
130#define KERN_PIPE_MAXBIGPIPES 3 /* maximum # of "big" pipes */
131#define KERN_PIPE_NBIGPIPES 4 /* current number of "big" p. */
132#define KERN_PIPE_KVASIZE 5 /* current pipe kva size */
133#define KERN_PIPE_MAXID 6
134
135#define CTL_PIPE_NAMES { \
136 { 0, 0 }, \
137 { "maxkvasz", CTLTYPE_INT }, \
138 { "maxloankvasz", CTLTYPE_INT }, \
139 { "maxbigpipes", CTLTYPE_INT }, \
140 { "nbigpipes", CTLTYPE_INT }, \
141 { "kvasize", CTLTYPE_INT }, \
142}
143
144#ifdef _KERNEL
145int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t);
146void pipe_init(void);
147#endif /* _KERNEL */
148
149#endif /* !_SYS_PIPE_H_ */
150