1 /* $OpenBSD: pipe.h,v 1.11 2003/10/03 16:38:03 miod 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 24 #ifndef _SYS_PIPE_H_ 25 #define _SYS_PIPE_H_ 26 27 #ifndef _KERNEL 28 #include <sys/time.h> /* for struct timeval */ 29 #include <sys/select.h> /* for struct selinfo */ 30 #include <uvm/uvm_extern.h> /* for vm_page_t */ 31 #include <machine/param.h> /* for PAGE_SIZE */ 32 #endif /* _KERNEL */ 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 (64*1024) 43 #endif 44 45 /* 46 * Pipe buffer information. 47 * Separate in, out, cnt are used to simplify calculations. 48 * Buffered write is active when the buffer.cnt field is set. 49 */ 50 struct pipebuf { 51 u_int cnt; /* number of chars currently in buffer */ 52 u_int in; /* in pointer */ 53 u_int out; /* out pointer */ 54 u_int size; /* size of buffer */ 55 caddr_t buffer; /* kva of buffer */ 56 }; 57 58 /* 59 * Bits in pipe_state. 60 */ 61 #define PIPE_ASYNC 0x004 /* Async? I/O. */ 62 #define PIPE_WANTR 0x008 /* Reader wants some characters. */ 63 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */ 64 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */ 65 #define PIPE_SEL 0x040 /* Pipe has a select active. */ 66 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */ 67 #define PIPE_LOCK 0x100 /* Process has exclusive access to pointers/data. */ 68 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */ 69 70 /* 71 * Per-pipe data structure. 72 * Two of these are linked together to produce bi-directional pipes. 73 */ 74 struct pipe { 75 struct pipebuf pipe_buffer; /* data storage */ 76 struct selinfo pipe_sel; /* for compat with select */ 77 struct timeval pipe_atime; /* time of last access */ 78 struct timeval pipe_mtime; /* time of last modify */ 79 struct timeval pipe_ctime; /* time of status change */ 80 int pipe_pgid; /* process/group for async I/O */ 81 struct pipe *pipe_peer; /* link with other direction */ 82 u_int pipe_state; /* pipe status info */ 83 int pipe_busy; /* busy flag, mostly to handle rundown sanely */ 84 }; 85 86 #ifdef _KERNEL 87 void pipe_init(void); 88 #endif /* _KERNEL */ 89 90 #endif /* !_SYS_PIPE_H_ */ 91