FreeBSD/Linux Kernel Cross Reference
sys/sys/pipe.h
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 * $FreeBSD$
22 */
23
24 #ifndef _SYS_PIPE_H_
25 #define _SYS_PIPE_H_
26
27 /*
28 * Pipe buffer size, keep moderate in value, pipes take kva space.
29 */
30 #ifndef PIPE_SIZE
31 #define PIPE_SIZE 16384
32 #endif
33
34 #ifndef BIG_PIPE_SIZE
35 #define BIG_PIPE_SIZE (64*1024)
36 #endif
37
38 #ifndef SMALL_PIPE_SIZE
39 #define SMALL_PIPE_SIZE PAGE_SIZE
40 #endif
41
42 /*
43 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
44 * than PIPE_BUF.
45 */
46 #ifndef PIPE_MINDIRECT
47 #define PIPE_MINDIRECT 8192
48 #endif
49
50 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
51
52 #ifdef _KERNEL
53 /*
54 * See sys_pipe.c for info on what these limits mean.
55 */
56 extern long maxpipekva;
57 extern struct fileops pipeops;
58 #endif
59
60 /*
61 * Pipe buffer information.
62 * Separate in, out, cnt are used to simplify calculations.
63 * Buffered write is active when the buffer.cnt field is set.
64 */
65 struct pipebuf {
66 u_int cnt; /* number of chars currently in buffer */
67 u_int in; /* in pointer */
68 u_int out; /* out pointer */
69 u_int size; /* size of buffer */
70 caddr_t buffer; /* kva of buffer */
71 };
72
73 /*
74 * Information to support direct transfers between processes for pipes.
75 */
76 struct pipemapping {
77 u_int cnt; /* number of chars in buffer */
78 u_int pos; /* current position of transfer */
79 int npages; /* number of pages */
80 vm_page_t ms[PIPENPAGES]; /* pages in source process */
81 };
82
83 /*
84 * Bits in pipe_state.
85 */
86 #define PIPE_ASYNC 0x004 /* Async? I/O. */
87 #define PIPE_WANTR 0x008 /* Reader wants some characters. */
88 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
89 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
90 #define PIPE_SEL 0x040 /* Pipe has a select active. */
91 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
92 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */
93 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
94 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
95 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
96
97 /*
98 * Bits in pipe_type.
99 */
100 #define PIPE_TYPE_NAMED 0x001 /* Is a named pipe. */
101
102 /*
103 * Per-pipe data structure.
104 * Two of these are linked together to produce bi-directional pipes.
105 */
106 struct pipe {
107 struct pipebuf pipe_buffer; /* data storage */
108 struct pipemapping pipe_pages; /* wired pages for direct I/O */
109 struct selinfo pipe_sel; /* for compat with select */
110 struct timespec pipe_atime; /* time of last access */
111 struct timespec pipe_mtime; /* time of last modify */
112 struct timespec pipe_ctime; /* time of status change */
113 struct sigio *pipe_sigio; /* information for async I/O */
114 struct pipe *pipe_peer; /* link with other direction */
115 struct pipepair *pipe_pair; /* container structure pointer */
116 u_short pipe_state; /* pipe status info */
117 u_char pipe_type; /* pipe type info */
118 u_char pipe_present; /* still present? */
119 int pipe_waiters; /* pipelock waiters */
120 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
121 int pipe_wgen; /* writer generation for named pipe */
122 ino_t pipe_ino; /* fake inode for stat(2) */
123 };
124
125 /*
126 * Values for the pipe_present.
127 */
128 #define PIPE_ACTIVE 1
129 #define PIPE_CLOSING 2
130 #define PIPE_FINALIZED 3
131
132 /*
133 * Container structure to hold the two pipe endpoints, mutex, and label
134 * pointer.
135 */
136 struct pipepair {
137 struct pipe pp_rpipe;
138 struct pipe pp_wpipe;
139 struct mtx pp_mtx;
140 struct label *pp_label;
141 };
142
143 #define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx)
144 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
145 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
146 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
147
148 #ifdef _KERNEL
149 void pipe_dtor(struct pipe *dpipe);
150 int pipe_named_ctor(struct pipe **ppipe, struct thread *td);
151 void pipeselwakeup(struct pipe *cpipe);
152 #endif
153 #endif /* !_SYS_PIPE_H_ */
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