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 * $FreeBSD$ 22 */ 23 24 #ifndef _SYS_PIPE_H_ 25 #define _SYS_PIPE_H_ 26 27 #ifndef _KERNEL 28 #error "no user-servicable parts inside" 29 #endif 30 31 /* 32 * Pipe buffer size, keep moderate in value, pipes take kva space. 33 */ 34 #ifndef PIPE_SIZE 35 #define PIPE_SIZE 16384 36 #endif 37 38 #ifndef BIG_PIPE_SIZE 39 #define BIG_PIPE_SIZE (64*1024) 40 #endif 41 42 #ifndef SMALL_PIPE_SIZE 43 #define SMALL_PIPE_SIZE PAGE_SIZE 44 #endif 45 46 /* 47 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger 48 * than PIPE_BUF. 49 */ 50 #ifndef PIPE_MINDIRECT 51 #define PIPE_MINDIRECT 8192 52 #endif 53 54 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1) 55 56 /* 57 * See sys_pipe.c for info on what these limits mean. 58 */ 59 extern long maxpipekva; 60 61 /* 62 * Pipe buffer information. 63 * Separate in, out, cnt are used to simplify calculations. 64 * Buffered write is active when the buffer.cnt field is set. 65 */ 66 struct pipebuf { 67 u_int cnt; /* number of chars currently in buffer */ 68 u_int in; /* in pointer */ 69 u_int out; /* out pointer */ 70 u_int size; /* size of buffer */ 71 caddr_t buffer; /* kva of buffer */ 72 }; 73 74 /* 75 * Information to support direct transfers between processes for pipes. 76 */ 77 struct pipemapping { 78 vm_size_t cnt; /* number of chars in buffer */ 79 vm_size_t pos; /* current position of transfer */ 80 int npages; /* number of pages */ 81 vm_page_t ms[PIPENPAGES]; /* pages in source process */ 82 }; 83 84 /* 85 * Bits in pipe_state. 86 */ 87 #define PIPE_ASYNC 0x004 /* Async? I/O. */ 88 #define PIPE_WANTR 0x008 /* Reader wants some characters. */ 89 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */ 90 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */ 91 #define PIPE_SEL 0x040 /* Pipe has a select active. */ 92 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */ 93 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */ 94 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */ 95 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */ 96 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */ 97 98 /* 99 * Per-pipe data structure. 100 * Two of these are linked together to produce bi-directional pipes. 101 */ 102 struct pipe { 103 struct pipebuf pipe_buffer; /* data storage */ 104 struct pipemapping pipe_map; /* pipe mapping for direct I/O */ 105 struct selinfo pipe_sel; /* for compat with select */ 106 struct timespec pipe_atime; /* time of last access */ 107 struct timespec pipe_mtime; /* time of last modify */ 108 struct timespec pipe_ctime; /* time of status change */ 109 struct sigio *pipe_sigio; /* information for async I/O */ 110 struct pipe *pipe_peer; /* link with other direction */ 111 struct pipepair *pipe_pair; /* container structure pointer */ 112 u_int pipe_state; /* pipe status info */ 113 int pipe_busy; /* busy flag, mostly to handle rundown sanely */ 114 int pipe_present; /* still present? */ 115 }; 116 117 /* 118 * Values for the pipe_present. 119 */ 120 #define PIPE_ACTIVE 1 121 #define PIPE_CLOSING 2 122 #define PIPE_FINALIZED 3 123 124 /* 125 * Container structure to hold the two pipe endpoints, mutex, and label 126 * pointer. 127 */ 128 struct pipepair { 129 struct pipe pp_rpipe; 130 struct pipe pp_wpipe; 131 struct mtx pp_mtx; 132 struct label *pp_label; 133 }; 134 135 #define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx) 136 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe)) 137 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe)) 138 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type)) 139 140 141 #endif /* !_SYS_PIPE_H_ */ 142