FreeBSD/Linux Kernel Cross Reference
sys/sys/pipe.h
1 /* $NetBSD: pipe.h,v 1.24.14.1 2009/02/24 02:34:47 snj 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 #ifndef _KERNEL
30 #include <sys/selinfo.h> /* for struct selinfo */
31 #endif
32
33 /*
34 * Pipe buffer size, keep moderate in value, pipes take kva space.
35 */
36 #ifndef PIPE_SIZE
37 #define PIPE_SIZE 16384
38 #endif
39
40 #ifndef BIG_PIPE_SIZE
41 #define BIG_PIPE_SIZE (4*PIPE_SIZE)
42 #endif
43
44 /*
45 * Maximum size of kva for direct write transfer. If the amount
46 * of data in buffer is larger, it would be transferred in chunks of this
47 * size. This kva memory is freed after use if amount of pipe kva memory
48 * is bigger than limitpipekva.
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 * Information to support direct transfers between processes for pipes.
77 */
78 struct pipemapping {
79 vaddr_t kva; /* kernel virtual address */
80 vsize_t cnt; /* number of chars in buffer */
81 voff_t pos; /* current position within page */
82 int npages; /* how many pages allocated */
83 struct vm_page **pgs; /* pointers to the pages */
84 };
85
86 /*
87 * Bits in pipe_state.
88 */
89 #define PIPE_ASYNC 0x001 /* Async I/O */
90 #define PIPE_EOF 0x010 /* Pipe is in EOF condition */
91 #define PIPE_SIGNALR 0x020 /* Do selwakeup() on read(2) */
92 #define PIPE_DIRECTW 0x040 /* Pipe in direct write mode setup */
93 #define PIPE_DIRECTR 0x080 /* Pipe direct read request (setup complete) */
94 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to
95 pointers/data. */
96 #define PIPE_LWANT 0x200 /* Process wants exclusive access to
97 pointers/data. */
98
99 /*
100 * Per-pipe data structure.
101 * Two of these are linked together to produce bi-directional pipes.
102 */
103 struct pipe {
104 kmutex_t *pipe_lock; /* pipe mutex */
105 kcondvar_t pipe_rcv; /* cv for readers */
106 kcondvar_t pipe_wcv; /* cv for writers */
107 kcondvar_t pipe_draincv; /* cv for close */
108 kcondvar_t pipe_lkcv; /* locking */
109 struct pipebuf pipe_buffer; /* data storage */
110 struct pipemapping pipe_map; /* pipe mapping for direct I/O */
111 struct selinfo pipe_sel; /* for compat with select */
112 struct timeval pipe_atime; /* time of last access */
113 struct timeval pipe_mtime; /* time of last modify */
114 struct timeval pipe_ctime; /* time of status change */
115 pid_t pipe_pgid; /* process group for sigio */
116 struct pipe *pipe_peer; /* link with other direction */
117 u_int pipe_state; /* pipe status info */
118 int pipe_busy; /* busy flag, to handle rundown */
119 vaddr_t pipe_kmem; /* preallocated PIPE_SIZE buffer */
120 };
121
122 /*
123 * KERN_PIPE subtypes
124 */
125 #define KERN_PIPE_MAXKVASZ 1 /* maximum kva size */
126 #define KERN_PIPE_LIMITKVA 2 /* */
127 #define KERN_PIPE_MAXBIGPIPES 3 /* maximum # of "big" pipes */
128 #define KERN_PIPE_NBIGPIPES 4 /* current number of "big" p. */
129 #define KERN_PIPE_KVASIZE 5 /* current pipe kva size */
130 #define KERN_PIPE_MAXID 6
131
132 #define CTL_PIPE_NAMES { \
133 { 0, 0 }, \
134 { "maxkvasz", CTLTYPE_INT }, \
135 { "maxloankvasz", CTLTYPE_INT }, \
136 { "maxbigpipes", CTLTYPE_INT }, \
137 { "nbigpipes", CTLTYPE_INT }, \
138 { "kvasize", CTLTYPE_INT }, \
139 }
140
141 #ifdef _KERNEL
142 int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t);
143 void pipe_init(void);
144 #endif /* _KERNEL */
145
146 #endif /* !_SYS_PIPE_H_ */
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