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-serviceable 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 extern struct fileops pipeops; 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 u_int cnt; /* number of chars currently in buffer */ 69 u_int in; /* in pointer */ 70 u_int out; /* out pointer */ 71 u_int size; /* size of buffer */ 72 caddr_t buffer; /* kva of buffer */ 73 }; 74 75 /* 76 * Information to support direct transfers between processes for pipes. 77 */ 78 struct pipemapping { 79 vm_size_t cnt; /* number of chars in buffer */ 80 vm_size_t pos; /* current position of transfer */ 81 int npages; /* number of pages */ 82 vm_page_t ms[PIPENPAGES]; /* pages in source process */ 83 }; 84 85 /* 86 * Bits in pipe_state. 87 */ 88 #define PIPE_ASYNC 0x004 /* Async? I/O. */ 89 #define PIPE_WANTR 0x008 /* Reader wants some characters. */ 90 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */ 91 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */ 92 #define PIPE_SEL 0x040 /* Pipe has a select active. */ 93 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */ 94 #define PIPE_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */ 95 #define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */ 96 #define PIPE_DIRECTW 0x400 /* Pipe direct write active. */ 97 #define PIPE_DIRECTOK 0x800 /* Direct mode ok. */ 98 99 /* 100 * Bits in pipe_type. 101 */ 102 #define PIPE_TYPE_NAMED 0x001 /* Is a named pipe. */ 103 104 /* 105 * Per-pipe data structure. 106 * Two of these are linked together to produce bi-directional pipes. 107 */ 108 struct pipe { 109 struct pipebuf pipe_buffer; /* data storage */ 110 struct pipemapping pipe_pages; /* wired pages for direct I/O */ 111 struct selinfo pipe_sel; /* for compat with select */ 112 struct timespec pipe_atime; /* time of last access */ 113 struct timespec pipe_mtime; /* time of last modify */ 114 struct timespec pipe_ctime; /* time of status change */ 115 struct sigio *pipe_sigio; /* information for async I/O */ 116 struct pipe *pipe_peer; /* link with other direction */ 117 struct pipepair *pipe_pair; /* container structure pointer */ 118 u_short pipe_state; /* pipe status info */ 119 u_char pipe_type; /* pipe type info */ 120 u_char pipe_present; /* still present? */ 121 int pipe_waiters; /* pipelock waiters */ 122 int pipe_busy; /* busy flag, mostly to handle rundown sanely */ 123 int pipe_wgen; /* writer generation for named pipe */ 124 ino_t pipe_ino; /* fake inode for stat(2) */ 125 }; 126 127 /* 128 * Values for the pipe_present. 129 */ 130 #define PIPE_ACTIVE 1 131 #define PIPE_CLOSING 2 132 #define PIPE_FINALIZED 3 133 134 /* 135 * Container structure to hold the two pipe endpoints, mutex, and label 136 * pointer. 137 */ 138 struct pipepair { 139 struct pipe pp_rpipe; 140 struct pipe pp_wpipe; 141 struct mtx pp_mtx; 142 struct label *pp_label; 143 }; 144 145 #define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx) 146 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe)) 147 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe)) 148 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type)) 149 150 void pipe_dtor(struct pipe *dpipe); 151 int pipe_named_ctor(struct pipe **ppipe, struct thread *td); 152 void pipeselwakeup(struct pipe *cpipe); 153 #endif /* !_SYS_PIPE_H_ */ 154