2 * Copyright (c) 1996 John S. Dyson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
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
28 #error "no user-servicable parts inside"
32 * Pipe buffer size, keep moderate in value, pipes take kva space.
35 #define PIPE_SIZE 16384
39 #define BIG_PIPE_SIZE (64*1024)
42 #ifndef SMALL_PIPE_SIZE
43 #define SMALL_PIPE_SIZE PAGE_SIZE
47 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
50 #ifndef PIPE_MINDIRECT
51 #define PIPE_MINDIRECT 8192
54 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
57 * See sys_pipe.c for info on what these limits mean.
59 extern long maxpipekva;
62 * Pipe buffer information.
63 * Separate in, out, cnt are used to simplify calculations.
64 * Buffered write is active when the buffer.cnt field is set.
67 u_int cnt; /* number of chars currently in buffer */
68 u_int in; /* in pointer */
69 u_int out; /* out pointer */
70 u_int size; /* size of buffer */
71 caddr_t buffer; /* kva of buffer */
75 * Information to support direct transfers between processes for pipes.
78 vm_size_t cnt; /* number of chars in buffer */
79 vm_size_t pos; /* current position of transfer */
80 int npages; /* number of pages */
81 vm_page_t ms[PIPENPAGES]; /* pages in source process */
87 #define PIPE_ASYNC 0x004 /* Async? I/O. */
88 #define PIPE_WANTR 0x008 /* Reader wants some characters. */
89 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
90 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */
91 #define PIPE_SEL 0x040 /* Pipe has a select active. */
92 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
93 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */
94 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
95 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
96 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
99 * Per-pipe data structure.
100 * Two of these are linked together to produce bi-directional pipes.
103 struct pipebuf pipe_buffer; /* data storage */
104 struct pipemapping pipe_map; /* pipe mapping for direct I/O */
105 struct selinfo pipe_sel; /* for compat with select */
106 struct timespec pipe_atime; /* time of last access */
107 struct timespec pipe_mtime; /* time of last modify */
108 struct timespec pipe_ctime; /* time of status change */
109 struct sigio *pipe_sigio; /* information for async I/O */
110 struct pipe *pipe_peer; /* link with other direction */
111 struct pipepair *pipe_pair; /* container structure pointer */
112 u_int pipe_state; /* pipe status info */
113 int pipe_busy; /* busy flag, mostly to handle rundown sanely */
114 int pipe_present; /* still present? */
118 * Values for the pipe_present.
120 #define PIPE_ACTIVE 1
121 #define PIPE_CLOSING 2
122 #define PIPE_FINALIZED 3
125 * Container structure to hold the two pipe endpoints, mutex, and label
129 struct pipe pp_rpipe;
130 struct pipe pp_wpipe;
132 struct label *pp_label;
135 #define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx)
136 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
137 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
138 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
141 #endif /* !_SYS_PIPE_H_ */