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: releng/5.1/sys/sys/pipe.h 101848 2002-08-14 01:04:43Z rwatson $
22 */
23
24 #ifndef _SYS_PIPE_H_
25 #define _SYS_PIPE_H_
26
27 #ifndef _KERNEL
28 #include <sys/time.h> /* for struct timespec */
29 #include <sys/selinfo.h> /* for struct selinfo */
30 #include <vm/vm.h> /* for vm_page_t */
31 #include <sys/_label.h> /* for struct label */
32 #include <machine/param.h> /* for PAGE_SIZE */
33 #endif
34
35 /*
36 * Pipe buffer size, keep moderate in value, pipes take kva space.
37 */
38 #ifndef PIPE_SIZE
39 #define PIPE_SIZE 16384
40 #endif
41
42 #ifndef BIG_PIPE_SIZE
43 #define BIG_PIPE_SIZE (64*1024)
44 #endif
45
46 /*
47 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
48 * than PIPE_BUF.
49 */
50 #ifndef PIPE_MINDIRECT
51 #define PIPE_MINDIRECT 8192
52 #endif
53
54 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
55
56 /*
57 * Pipe buffer information.
58 * Separate in, out, cnt are used to simplify calculations.
59 * Buffered write is active when the buffer.cnt field is set.
60 */
61 struct pipebuf {
62 u_int cnt; /* number of chars currently in buffer */
63 u_int in; /* in pointer */
64 u_int out; /* out pointer */
65 u_int size; /* size of buffer */
66 caddr_t buffer; /* kva of buffer */
67 struct vm_object *object; /* VM object containing buffer */
68 };
69
70 /*
71 * Information to support direct transfers between processes for pipes.
72 */
73 struct pipemapping {
74 vm_offset_t kva; /* kernel virtual address */
75 vm_size_t cnt; /* number of chars in buffer */
76 vm_size_t pos; /* current position of transfer */
77 int npages; /* number of pages */
78 vm_page_t ms[PIPENPAGES]; /* pages in source process */
79 };
80
81 /*
82 * Bits in pipe_state.
83 */
84 #define PIPE_ASYNC 0x004 /* Async? I/O. */
85 #define PIPE_WANTR 0x008 /* Reader wants some characters. */
86 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
87 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
88 #define PIPE_SEL 0x040 /* Pipe has a select active. */
89 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
90 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */
91 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
92 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
93 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
94
95 /*
96 * Per-pipe data structure.
97 * Two of these are linked together to produce bi-directional pipes.
98 */
99 struct pipe {
100 struct pipebuf pipe_buffer; /* data storage */
101 struct pipemapping pipe_map; /* pipe mapping for direct I/O */
102 struct selinfo pipe_sel; /* for compat with select */
103 struct timespec pipe_atime; /* time of last access */
104 struct timespec pipe_mtime; /* time of last modify */
105 struct timespec pipe_ctime; /* time of status change */
106 struct sigio *pipe_sigio; /* information for async I/O */
107 struct pipe *pipe_peer; /* link with other direction */
108 u_int pipe_state; /* pipe status info */
109 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
110 struct label *pipe_label; /* pipe MAC label - shared */
111 struct mtx *pipe_mtxp; /* shared mutex between both pipes */
112 };
113
114 #define PIPE_MTX(pipe) (pipe)->pipe_mtxp
115 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
116 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
117 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
118
119
120 #endif /* !_SYS_PIPE_H_ */
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