| 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 | |