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 22 #ifndef _SYS_PIPE_H_ 23 #define _SYS_PIPE_H_ 24 25 /* 26 * Pipe buffer size, keep moderate in value, pipes take kva space. 27 */ 28 #ifndef PIPE_SIZE 29 #define PIPE_SIZE 16384 30 #endif 31 32 #ifndef BIG_PIPE_SIZE 33 #define BIG_PIPE_SIZE (64*1024) 34 #endif 35 36 #ifndef SMALL_PIPE_SIZE 37 #define SMALL_PIPE_SIZE PAGE_SIZE 38 #endif 39 40 /* 41 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger 42 * than PIPE_BUF. 43 */ 44 #ifndef PIPE_MINDIRECT 45 #define PIPE_MINDIRECT 8192 46 #endif 47 48 #define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1) 49 50 #ifdef _KERNEL 51 /* 52 * See sys_pipe.c for info on what these limits mean. 53 */ 54 extern long maxpipekva; 55 extern const struct fileops pipeops; 56 #endif 57 58 /* 59 * Pipe buffer information. 60 * Separate in, out, cnt are used to simplify calculations. 61 * Buffered write is active when the buffer.cnt field is set. 62 */ 63 struct pipebuf { 64 u_int cnt; /* number of chars currently in buffer */ 65 u_int in; /* in pointer */ 66 u_int out; /* out pointer */ 67 u_int size; /* size of buffer */ 68 caddr_t buffer; /* kva of buffer */ 69 }; 70 71 /* 72 * Information to support direct transfers between processes for pipes. 73 */ 74 struct pipemapping { 75 u_int cnt; /* number of chars in buffer */ 76 u_int pos; /* current position of transfer */ 77 int npages; /* number of pages */ 78 vm_page_t ms[PIPENPAGES]; /* pages in source process */ 79 }; 80 81 /* 82 * Bits in pipe_state. 83 */ 84 #define PIPE_ASYNC 0x004 /* Async? I/O. */ 85 #define PIPE_WANTR 0x008 /* Reader wants some characters. */ 86 #define PIPE_WANTW 0x010 /* Writer wants space to put characters. */ 87 #define PIPE_WANT 0x020 /* Pipe is wanted to be run-down. */ 88 #define PIPE_SEL 0x040 /* Pipe has a select active. */ 89 #define PIPE_EOF 0x080 /* Pipe is in EOF condition. */ 90 #define PIPE_LOCKFL 0x100 /* Process has 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 * Bits in pipe_type. 96 */ 97 #define PIPE_TYPE_NAMED 0x001 /* Is a named pipe. */ 98 99 /* 100 * Per-pipe data structure. 101 * Two of these are linked together to produce bi-directional pipes. 102 */ 103 struct pipe { 104 struct pipebuf pipe_buffer; /* data storage */ 105 struct pipemapping pipe_pages; /* wired pages for direct I/O */ 106 struct selinfo pipe_sel; /* for compat with select */ 107 struct timespec pipe_atime; /* time of last access */ 108 struct timespec pipe_mtime; /* time of last modify */ 109 struct timespec pipe_ctime; /* time of status change */ 110 struct sigio *pipe_sigio; /* information for async I/O */ 111 struct pipe *pipe_peer; /* link with other direction */ 112 struct pipepair *pipe_pair; /* container structure pointer */ 113 u_short pipe_state; /* pipe status info */ 114 u_char pipe_type; /* pipe type info */ 115 u_char pipe_present; /* still present? */ 116 int pipe_waiters; /* pipelock waiters */ 117 int pipe_busy; /* busy flag, mostly to handle rundown sanely */ 118 int pipe_wgen; /* writer generation for named pipe */ 119 ino_t pipe_ino; /* fake inode for stat(2) */ 120 }; 121 122 /* 123 * Values for the pipe_present. 124 */ 125 #define PIPE_ACTIVE 1 126 #define PIPE_CLOSING 2 127 #define PIPE_FINALIZED 3 128 129 /* 130 * Container structure to hold the two pipe endpoints, mutex, and label 131 * pointer. 132 */ 133 struct pipepair { 134 struct pipe pp_rpipe; 135 struct pipe pp_wpipe; 136 struct mtx pp_mtx; 137 struct label *pp_label; 138 struct ucred *pp_owner; /* to dec pipe usage count */ 139 }; 140 141 #define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx) 142 #define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe)) 143 #define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe)) 144 #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type)) 145 146 #ifdef _KERNEL 147 void pipe_dtor(struct pipe *dpipe); 148 int pipe_named_ctor(struct pipe **ppipe, struct thread *td); 149 void pipeselwakeup(struct pipe *cpipe); 150 #endif 151 #endif /* !_SYS_PIPE_H_ */ 152