FreeBSD/Linux Kernel Cross Reference
sys/sys/pipe.h
1 /* $NetBSD: pipe.h,v 1.38 2021/01/25 19:21:11 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 transfer for direct write transfer. If the amount
47 * of data in buffer is larger, it would be transferred in chunks of this
48 * size.
49 */
50 #ifndef PIPE_DIRECT_CHUNK
51 #define PIPE_DIRECT_CHUNK (1*1024*1024)
52 #endif
53
54 /*
55 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
56 * than PIPE_BUF.
57 */
58 #ifndef PIPE_MINDIRECT
59 #define PIPE_MINDIRECT 8192
60 #endif
61
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 */
67 struct pipebuf {
68 size_t cnt; /* number of chars currently in buffer */
69 u_int in; /* in pointer */
70 u_int out; /* out pointer */
71 size_t size; /* size of buffer */
72 void * buffer; /* kva of buffer */
73 };
74
75 /*
76 * Bits in pipe_state.
77 */
78 #define PIPE_ASYNC 0x001 /* Async I/O */
79 #define PIPE_EOF 0x010 /* Pipe is in EOF condition */
80 #define PIPE_SIGNALR 0x020 /* Do selwakeup() on read(2) */
81 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to
82 pointers/data. */
83 /* unused 0x200 */
84 #define PIPE_RESTART 0x400 /* Return ERESTART to blocked syscalls */
85
86 /*
87 * Per-pipe data structure.
88 * Two of these are linked together to produce bi-directional pipes.
89 */
90 struct pipe {
91 kmutex_t *pipe_lock; /* pipe mutex */
92 kcondvar_t pipe_rcv; /* cv for readers */
93 kcondvar_t pipe_wcv; /* cv for writers */
94 kcondvar_t pipe_draincv; /* cv for close */
95 kcondvar_t pipe_lkcv; /* locking */
96 struct pipebuf pipe_buffer; /* data storage */
97 struct selinfo pipe_sel; /* for compat with select */
98 struct timespec pipe_atime; /* time of last access */
99 struct timespec pipe_mtime; /* time of last modify */
100 struct timespec pipe_btime; /* time of creation */
101 pid_t pipe_pgid; /* process group for sigio */
102 u_int pipe_waiters; /* number of waiters pending */
103 struct pipe *pipe_peer; /* link with other direction */
104 u_int pipe_state; /* pipe status info */
105 int pipe_busy; /* busy flag, to handle rundown */
106 vaddr_t pipe_kmem; /* preallocated PIPE_SIZE buffer */
107 };
108
109 /*
110 * KERN_PIPE subtypes
111 */
112 #define KERN_PIPE_MAXKVASZ 1 /* maximum kva size (obsolete) */
113 #define KERN_PIPE_LIMITKVA 2 /* limit kva for laons (obsolete) */
114 #define KERN_PIPE_MAXBIGPIPES 3 /* maximum # of "big" pipes */
115 #define KERN_PIPE_NBIGPIPES 4 /* current number of "big" p. */
116 #define KERN_PIPE_KVASIZE 5 /* current pipe kva size */
117
118 #ifdef _KERNEL
119 int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t);
120 void pipe_init(void);
121 #endif /* _KERNEL */
122
123 #endif /* !_SYS_PIPE_H_ */
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