1 /* $NetBSD: pipe.h,v 1.42 2023/11/02 10:31:55 martin 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 transfer for direct write transfer. If the amount 47 * of data in buffer is larger, it would be transferred in chunks of this 48 * size. 49 */ 50 #ifndef PIPE_DIRECT_CHUNK 51 #define PIPE_DIRECT_CHUNK (1*1024*1024) 52 #endif 53 54 /* 55 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger 56 * than PIPE_BUF. 57 */ 58 #ifndef PIPE_MINDIRECT 59 #define PIPE_MINDIRECT 8192 60 #endif 61 62 /* 63 * Pipe buffer information. 64 * Separate in, out, cnt are used to simplify calculations. 65 * Buffered write is active when the buffer.cnt field is set. 66 */ 67 struct pipebuf { 68 size_t cnt; /* number of chars currently in buffer */ 69 u_int in; /* in pointer */ 70 u_int out; /* out pointer */ 71 size_t size; /* size of buffer */ 72 void * buffer; /* kva of buffer */ 73 }; 74 75 /* 76 * Bits in pipe_state. 77 */ 78 #define PIPE_ASYNC 0x001 /* Async I/O */ 79 #define PIPE_EOF 0x010 /* Pipe is in EOF condition */ 80 #define PIPE_SIGNALR 0x020 /* Do selwakeup() on read(2) */ 81 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to 82 pointers/data. */ 83 /* unused 0x200 */ 84 #define PIPE_RESTART 0x400 /* Return ERESTART to blocked syscalls */ 85 86 /* 87 * Per-pipe data structure. 88 * Two of these are linked together to produce bi-directional pipes. 89 */ 90 struct pipe { 91 kmutex_t *pipe_lock; /* pipe mutex */ 92 kcondvar_t pipe_rcv; /* cv for readers */ 93 kcondvar_t pipe_wcv; /* cv for writers */ 94 kcondvar_t pipe_draincv; /* cv for close */ 95 kcondvar_t pipe_lkcv; /* locking */ 96 struct pipebuf pipe_buffer; /* data storage */ 97 struct selinfo pipe_sel; /* for compat with select */ 98 struct timespec pipe_atime; /* time of last access */ 99 struct timespec pipe_mtime; /* time of last modify */ 100 struct timespec pipe_btime; /* time of creation */ 101 struct pipe *pipe_peer; /* link with other direction */ 102 pid_t pipe_pgid; /* process group for sigio */ 103 u_int pipe_state; /* pipe status info */ 104 int pipe_busy; /* busy flag, to handle rundown */ 105 vaddr_t pipe_kmem; /* preallocated PIPE_SIZE buffer */ 106 }; 107 108 /* 109 * KERN_PIPE subtypes 110 */ 111 #define KERN_PIPE_MAXKVASZ 1 /* maximum kva size (obsolete) */ 112 #define KERN_PIPE_LIMITKVA 2 /* limit kva for laons (obsolete) */ 113 #define KERN_PIPE_MAXBIGPIPES 3 /* maximum # of "big" pipes */ 114 #define KERN_PIPE_NBIGPIPES 4 /* current number of "big" p. */ 115 #define KERN_PIPE_KVASIZE 5 /* current pipe kva size */ 116 117 #ifdef _KERNEL 118 int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t); 119 void pipe_init(void); 120 #endif /* _KERNEL */ 121 122 #endif /* !_SYS_PIPE_H_ */ 123