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 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};
140
141#define PIPE_MTX(pipe)		(&(pipe)->pipe_pair->pp_mtx)
142#define PIPE_LOCK(pipe)		mtx_lock(PIPE_MTX(pipe))
143#define PIPE_UNLOCK(pipe)	mtx_unlock(PIPE_MTX(pipe))
144#define PIPE_LOCK_ASSERT(pipe, type)  mtx_assert(PIPE_MTX(pipe), (type))
145
146#ifdef _KERNEL
147void	pipe_dtor(struct pipe *dpipe);
148int	pipe_named_ctor(struct pipe **ppipe, struct thread *td);
149void	pipeselwakeup(struct pipe *cpipe);
150#endif
151#endif /* !_SYS_PIPE_H_ */
152