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: src/sys/sys/pipe.h,v 1.6.2.1 1999/09/05 08:22:43 peter Exp $
22 */
23
24 #ifndef _SYS_PIPE_H_
25 #define _SYS_PIPE_H_
26
27 #ifndef OLD_PIPE
28
29 #ifndef KERNEL
30 #include <sys/time.h> /* for struct timeval */
31 #include <sys/select.h> /* for struct selinfo */
32 #include <vm/vm.h> /* for vm_page_t */
33 #include <machine/param.h> /* for PAGE_SIZE */
34 #endif
35
36 /*
37 * Pipe buffer size, keep moderate in value, pipes take kva space.
38 */
39 #ifndef PIPE_SIZE
40 #define PIPE_SIZE 16384
41 #endif
42
43 #ifndef BIG_PIPE_SIZE
44 #define BIG_PIPE_SIZE (64*1024)
45 #endif
46
47 /*
48 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
49 * than PIPE_BUF.
50 */
51 #ifndef PIPE_MINDIRECT
52 #define PIPE_MINDIRECT 8192
53 #endif
54
55 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
56
57 /*
58 * Pipe buffer information.
59 * Separate in, out, cnt are used to simplify calculations.
60 * Buffered write is active when the buffer.cnt field is set.
61 */
62 struct pipebuf {
63 u_int cnt; /* number of chars currently in buffer */
64 u_int in; /* in pointer */
65 u_int out; /* out pointer */
66 u_int size; /* size of buffer */
67 caddr_t buffer; /* kva of buffer */
68 struct vm_object *object; /* VM object containing buffer */
69 };
70
71 /*
72 * Information to support direct transfers between processes for pipes.
73 */
74 struct pipemapping {
75 vm_offset_t kva; /* kernel virtual address */
76 vm_size_t cnt; /* number of chars in buffer */
77 vm_size_t pos; /* current position of transfer */
78 int npages; /* number of pages */
79 vm_page_t ms[PIPENPAGES]; /* pages in source process */
80 };
81
82 /*
83 * Bits in pipe_state.
84 */
85 #define PIPE_ASYNC 0x004 /* Async? I/O. */
86 #define PIPE_WANTR 0x008 /* Reader wants some characters. */
87 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
88 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
89 #define PIPE_SEL 0x040 /* Pipe has a select active. */
90 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
91 #define PIPE_LOCK 0x100 /* Process has exclusive access to pointers/data. */
92 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
93 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
94 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
95
96 /*
97 * Per-pipe data structure.
98 * Two of these are linked together to produce bi-directional pipes.
99 */
100 struct pipe {
101 struct pipebuf pipe_buffer; /* data storage */
102 struct pipemapping pipe_map; /* pipe mapping for direct I/O */
103 struct selinfo pipe_sel; /* for compat with select */
104 struct timeval pipe_atime; /* time of last access */
105 struct timeval pipe_mtime; /* time of last modify */
106 struct timeval pipe_ctime; /* time of status change */
107 int pipe_pgid; /* process/group for async I/O */
108 struct pipe *pipe_peer; /* link with other direction */
109 u_int pipe_state; /* pipe status info */
110 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
111 };
112
113 #ifdef KERNEL
114 int pipe_stat __P((struct pipe *pipe, struct stat *ub));
115 #endif
116
117 #endif /* !OLD_PIPE */
118
119 #endif /* !_SYS_PIPE_H_ */
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