1 /* 2 * Copyright (c) 1996 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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 15 * John S. Dyson. 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 19 * are met. 20 * 21 * $FreeBSD: src/sys/sys/pipe.h,v 1.16 1999/12/29 04:24:45 peter Exp $ 22 */ 23 24 #ifndef _SYS_PIPE_H_ 25 #define _SYS_PIPE_H_ 26 27 #ifndef _KERNEL 28 #include <sys/time.h> /* for struct timespec */ 29 #include <sys/select.h> /* for struct selinfo */ 30 #include <vm/vm.h> /* for vm_page_t */ 31 #include <machine/param.h> /* for PAGE_SIZE */ 32 #endif 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_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger 47 * than PIPE_BUF. 48 */ 49 #ifndef PIPE_MINDIRECT 50 #define PIPE_MINDIRECT 8192 51 #endif 52 53 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1) 54 55 /* 56 * Pipe buffer information. 57 * Separate in, out, cnt are used to simplify calculations. 58 * Buffered write is active when the buffer.cnt field is set. 59 */ 60 struct pipebuf { 61 u_int cnt; /* number of chars currently in buffer */ 62 u_int in; /* in pointer */ 63 u_int out; /* out pointer */ 64 u_int size; /* size of buffer */ 65 caddr_t buffer; /* kva of buffer */ 66 struct vm_object *object; /* VM object containing buffer */ 67 }; 68 69 /* 70 * Information to support direct transfers between processes for pipes. 71 */ 72 struct pipemapping { 73 vm_offset_t kva; /* kernel virtual address */ 74 vm_size_t cnt; /* number of chars in buffer */ 75 vm_size_t pos; /* current position of transfer */ 76 int npages; /* number of pages */ 77 vm_page_t ms[PIPENPAGES]; /* pages in source process */ 78 }; 79 80 /* 81 * Bits in pipe_state. 82 */ 83 #define PIPE_ASYNC 0x004 /* Async? I/O. */ 84 #define PIPE_WANTR 0x008 /* Reader wants some characters. */ 85 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */ 86 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */ 87 #define PIPE_SEL 0x040 /* Pipe has a select active. */ 88 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */ 89 #define PIPE_LOCK 0x100 /* Process has exclusive access to pointers/data. */ 90 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */ 91 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */ 92 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */ 93 94 /* 95 * Per-pipe data structure. 96 * Two of these are linked together to produce bi-directional pipes. 97 */ 98 struct pipe { 99 struct pipebuf pipe_buffer; /* data storage */ 100 struct pipemapping pipe_map; /* pipe mapping for direct I/O */ 101 struct selinfo pipe_sel; /* for compat with select */ 102 struct timespec pipe_atime; /* time of last access */ 103 struct timespec pipe_mtime; /* time of last modify */ 104 struct timespec pipe_ctime; /* time of status change */ 105 struct sigio *pipe_sigio; /* information for async I/O */ 106 struct pipe *pipe_peer; /* link with other direction */ 107 u_int pipe_state; /* pipe status info */ 108 int pipe_busy; /* busy flag, mostly to handle rundown sanely */ 109 }; 110 111 #endif /* !_SYS_PIPE_H_ */ 112