1 /* $OpenBSD: pipe.h,v 1.13 2005/11/21 18:16:46 millert 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
24 #ifndef _SYS_PIPE_H_
25 #define _SYS_PIPE_H_
26
27 #ifndef _KERNEL
28 #include <sys/time.h> /* for struct timeval */
29 #include <sys/selinfo.h> /* for struct selinfo */
30 #include <uvm/uvm_extern.h> /* for vm_page_t */
31 #include <machine/param.h> /* for PAGE_SIZE */
32 #endif /* _KERNEL */
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 (64*1024)
43 #endif
44
45 /*
46 * Pipe buffer information.
47 * Separate in, out, cnt are used to simplify calculations.
48 * Buffered write is active when the buffer.cnt field is set.
49 */
50 struct pipebuf {
51 u_int cnt; /* number of chars currently in buffer */
52 u_int in; /* in pointer */
53 u_int out; /* out pointer */
54 u_int size; /* size of buffer */
55 caddr_t buffer; /* kva of buffer */
56 };
57
58 /*
59 * Bits in pipe_state.
60 */
61 #define PIPE_ASYNC 0x004 /* Async? I/O. */
62 #define PIPE_WANTR 0x008 /* Reader wants some characters. */
63 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
64 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
65 #define PIPE_SEL 0x040 /* Pipe has a select active. */
66 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
67 #define PIPE_LOCK 0x100 /* Process has exclusive access to pointers/data. */
68 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
69
70 /*
71 * Per-pipe data structure.
72 * Two of these are linked together to produce bi-directional pipes.
73 */
74 struct pipe {
75 struct pipebuf pipe_buffer; /* data storage */
76 struct selinfo pipe_sel; /* for compat with select */
77 struct timespec pipe_atime; /* time of last access */
78 struct timespec pipe_mtime; /* time of last modify */
79 struct timespec pipe_ctime; /* time of status change */
80 int pipe_pgid; /* process/group for async I/O */
81 struct pipe *pipe_peer; /* link with other direction */
82 u_int pipe_state; /* pipe status info */
83 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
84 };
85
86 #ifdef _KERNEL
87 void pipe_init(void);
88 #endif /* _KERNEL */
89
90 #endif /* !_SYS_PIPE_H_ */