1 | /* $NetBSD: pipe.h,v 1.33 2016/01/22 23:38:45 dholland 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 | * $FreeBSD: src/sys/sys/pipe.h,v 1.18 2002/02/27 07:35:59 alfred Exp $ |
24 | */ |
25 | |
26 | #ifndef _SYS_PIPE_H_ |
27 | #define _SYS_PIPE_H_ |
28 | |
29 | #include <sys/selinfo.h> /* for struct selinfo */ |
30 | #include <sys/time.h> /* for struct timespec */ |
31 | |
32 | #include <uvm/uvm_extern.h> |
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 (4*PIPE_SIZE) |
43 | #endif |
44 | |
45 | /* |
46 | * Maximum size of kva for direct write transfer. If the amount |
47 | * of data in buffer is larger, it would be transferred in chunks of this |
48 | * size. This kva memory is freed after use if amount of pipe kva memory |
49 | * is bigger than limitpipekva. |
50 | */ |
51 | #ifndef PIPE_DIRECT_CHUNK |
52 | #define PIPE_DIRECT_CHUNK (1*1024*1024) |
53 | #endif |
54 | |
55 | /* |
56 | * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger |
57 | * than PIPE_BUF. |
58 | */ |
59 | #ifndef PIPE_MINDIRECT |
60 | #define PIPE_MINDIRECT 8192 |
61 | #endif |
62 | |
63 | /* |
64 | * Pipe buffer information. |
65 | * Separate in, out, cnt are used to simplify calculations. |
66 | * Buffered write is active when the buffer.cnt field is set. |
67 | */ |
68 | struct pipebuf { |
69 | size_t cnt; /* number of chars currently in buffer */ |
70 | u_int in; /* in pointer */ |
71 | u_int out; /* out pointer */ |
72 | size_t size; /* size of buffer */ |
73 | void * buffer; /* kva of buffer */ |
74 | }; |
75 | |
76 | /* |
77 | * Information to support direct transfers between processes for pipes. |
78 | */ |
79 | struct pipemapping { |
80 | vaddr_t kva; /* kernel virtual address */ |
81 | vsize_t cnt; /* number of chars in buffer */ |
82 | voff_t pos; /* current position within page */ |
83 | int npages; /* how many pages allocated */ |
84 | struct vm_page **pgs; /* pointers to the pages */ |
85 | u_int egen; /* emap generation number */ |
86 | }; |
87 | |
88 | /* |
89 | * Bits in pipe_state. |
90 | */ |
91 | #define PIPE_ASYNC 0x001 /* Async I/O */ |
92 | #define PIPE_EOF 0x010 /* Pipe is in EOF condition */ |
93 | #define PIPE_SIGNALR 0x020 /* Do selwakeup() on read(2) */ |
94 | #define PIPE_DIRECTW 0x040 /* Pipe in direct write mode setup */ |
95 | #define PIPE_DIRECTR 0x080 /* Pipe direct read request (setup complete) */ |
96 | #define PIPE_LOCKFL 0x100 /* Process has exclusive access to |
97 | pointers/data. */ |
98 | #define PIPE_LWANT 0x200 /* Process wants exclusive access to |
99 | pointers/data. */ |
100 | #define PIPE_RESTART 0x400 /* Return ERESTART to blocked syscalls */ |
101 | |
102 | /* |
103 | * Per-pipe data structure. |
104 | * Two of these are linked together to produce bi-directional pipes. |
105 | */ |
106 | struct pipe { |
107 | kmutex_t *pipe_lock; /* pipe mutex */ |
108 | kcondvar_t pipe_rcv; /* cv for readers */ |
109 | kcondvar_t pipe_wcv; /* cv for writers */ |
110 | kcondvar_t pipe_draincv; /* cv for close */ |
111 | kcondvar_t pipe_lkcv; /* locking */ |
112 | struct pipebuf pipe_buffer; /* data storage */ |
113 | struct pipemapping pipe_map; /* pipe mapping for direct I/O */ |
114 | struct selinfo pipe_sel; /* for compat with select */ |
115 | struct timespec pipe_atime; /* time of last access */ |
116 | struct timespec pipe_mtime; /* time of last modify */ |
117 | struct timespec pipe_btime; /* time of creation */ |
118 | pid_t pipe_pgid; /* process group for sigio */ |
119 | struct pipe *pipe_peer; /* link with other direction */ |
120 | u_int pipe_state; /* pipe status info */ |
121 | int pipe_busy; /* busy flag, to handle rundown */ |
122 | vaddr_t pipe_kmem; /* preallocated PIPE_SIZE buffer */ |
123 | }; |
124 | |
125 | /* |
126 | * KERN_PIPE subtypes |
127 | */ |
128 | #define KERN_PIPE_MAXKVASZ 1 /* maximum kva size */ |
129 | #define KERN_PIPE_LIMITKVA 2 /* */ |
130 | #define KERN_PIPE_MAXBIGPIPES 3 /* maximum # of "big" pipes */ |
131 | #define KERN_PIPE_NBIGPIPES 4 /* current number of "big" p. */ |
132 | #define KERN_PIPE_KVASIZE 5 /* current pipe kva size */ |
133 | #define KERN_PIPE_MAXID 6 |
134 | |
135 | #define CTL_PIPE_NAMES { \ |
136 | { 0, 0 }, \ |
137 | { "maxkvasz", CTLTYPE_INT }, \ |
138 | { "maxloankvasz", CTLTYPE_INT }, \ |
139 | { "maxbigpipes", CTLTYPE_INT }, \ |
140 | { "nbigpipes", CTLTYPE_INT }, \ |
141 | { "kvasize", CTLTYPE_INT }, \ |
142 | } |
143 | |
144 | #ifdef _KERNEL |
145 | int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t); |
146 | void pipe_init(void); |
147 | #endif /* _KERNEL */ |
148 | |
149 | #endif /* !_SYS_PIPE_H_ */ |
150 | |