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
22#ifndef _SYS_PIPE_H_
23#define _SYS_PIPE_H_
24
25/*
26 * Pipe buffer size, keep moderate in value, pipes take kva space.
27 */
28#ifndef PIPE_SIZE
29#define PIPE_SIZE 16384
30#endif
31
32#ifndef BIG_PIPE_SIZE
33#define BIG_PIPE_SIZE (64*1024)
34#endif
35
36#ifndef SMALL_PIPE_SIZE
37#define SMALL_PIPE_SIZE PAGE_SIZE
38#endif
39
40/*
41 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
42 * than PIPE_BUF.
43 */
44#ifndef PIPE_MINDIRECT
45#define PIPE_MINDIRECT 8192
46#endif
47
48#define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
49
50#ifdef _KERNEL
51/*
52 * See sys_pipe.c for info on what these limits mean.
53 */
54extern long maxpipekva;
55extern const struct fileops pipeops;
56#endif
57
58/*
59 * Pipe buffer information.
60 * Separate in, out, cnt are used to simplify calculations.
61 * Buffered write is active when the buffer.cnt field is set.
62 */
63struct pipebuf {
64 u_int cnt; /* number of chars currently in buffer */
65 u_int in; /* in pointer */
66 u_int out; /* out pointer */
67 u_int size; /* size of buffer */
68 caddr_t buffer; /* kva of buffer */
69};
70
71/*
72 * Information to support direct transfers between processes for pipes.
73 */
74struct pipemapping {
75 u_int cnt; /* number of chars in buffer */
76 u_int 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 * Bits in pipe_type.
97 */
98#define PIPE_TYPE_NAMED 0x001 /* Is a named pipe. */
99
100/*
101 * Per-pipe data structure.
102 * Two of these are linked together to produce bi-directional pipes.
103 */
104struct pipe {
105 struct pipebuf pipe_buffer; /* data storage */
106 struct pipemapping pipe_pages; /* wired pages for direct I/O */
107 struct selinfo pipe_sel; /* for compat with select */
108 struct timespec pipe_atime; /* time of last access */
109 struct timespec pipe_mtime; /* time of last modify */
110 struct timespec pipe_ctime; /* time of status change */
111 struct sigio *pipe_sigio; /* information for async I/O */
112 struct pipe *pipe_peer; /* link with other direction */
113 struct pipepair *pipe_pair; /* container structure pointer */
114 u_short pipe_state; /* pipe status info */
115 u_char pipe_type; /* pipe type info */
116 u_char pipe_present; /* still present? */
117 int pipe_waiters; /* pipelock waiters */
118 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
119 int pipe_wgen; /* writer generation for named pipe */
120 ino_t pipe_ino; /* fake inode for stat(2) */
121};
122
123/*
124 * Values for the pipe_present.
125 */
126#define PIPE_ACTIVE 1
127#define PIPE_CLOSING 2
128#define PIPE_FINALIZED 3
129
130/*
131 * Container structure to hold the two pipe endpoints, mutex, and label
132 * pointer.
133 */
134struct pipepair {
135 struct pipe pp_rpipe;
136 struct pipe pp_wpipe;
137 struct mtx pp_mtx;
138 struct label *pp_label;
139 struct ucred *pp_owner; /* to dec pipe usage count */
140};
141
142#define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx)
143#define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
144#define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
145#define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
146
147#ifdef _KERNEL
148void pipe_dtor(struct pipe *dpipe);
149int pipe_named_ctor(struct pipe **ppipe, struct thread *td);
150void pipeselwakeup(struct pipe *cpipe);
151#endif
152#endif /* !_SYS_PIPE_H_ */