bsd/sys/pipe.h

   1 /*
   2  * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1996 John S. Dyson
  24  * All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice immediately at the beginning of the file, without modification,
  31  *    this list of conditions, and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. Absolutely no warranty of function or purpose is made by the author
  36  *    John S. Dyson.
  37  * 4. This work was done expressly for inclusion into FreeBSD.  Other use
  38  *    is allowed if this notation is included.
  39  * 5. Modifications may be freely made to this file if the above conditions
  40  *    are met.
  41  *
  42  * $FreeBSD: src/sys/sys/pipe.h,v 1.24 2003/08/13 20:01:38 alc Exp $
  43  */
  44
  45 #ifndef _SYS_PIPE_H_
  46 #define _SYS_PIPE_H_
  47
  48 #ifdef  KERNEL
  49 #include <libkern/locks.h>
  50 #endif
  51 #include <sys/queue.h>                  /* for TAILQ macros */
  52 #include <sys/ev.h>
  53 #include <sys/cdefs.h>
  54
  55 /*
  56  * Pipe buffer size, keep moderate in value, pipes take kva space.
  57  */
  58 #ifndef PIPE_SIZE
  59 #define PIPE_SIZE       16384
  60 #endif
  61
  62 #ifndef BIG_PIPE_SIZE
  63 #define BIG_PIPE_SIZE   (64*1024)
  64 #endif
  65
  66 #ifndef SMALL_PIPE_SIZE
  67 #define SMALL_PIPE_SIZE PAGE_SIZE
  68 #endif
  69
  70 /*
  71  * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
  72  * than PIPE_BUF.
  73  */
  74 #ifndef PIPE_MINDIRECT
  75 #define PIPE_MINDIRECT  8192
  76 #endif
  77
  78 #define PIPENPAGES      (BIG_PIPE_SIZE / PAGE_SIZE + 1)
  79
  80 /*
  81  * Pipe buffer information.
  82  * Separate in, out, cnt are used to simplify calculations.
  83  * Buffered write is active when the buffer.cnt field is set.
  84  */
  85 struct pipebuf {
  86         u_int   cnt;            /* number of chars currently in buffer */
  87         u_int   in;             /* in pointer */
  88         u_int   out;            /* out pointer */
  89         u_int   size;           /* size of buffer */
  90         caddr_t buffer;         /* kva of buffer */
  91 };
  92
  93
  94 #ifdef PIPE_DIRECT
  95 /*
  96  * Information to support direct transfers between processes for pipes.
  97  */
  98 /* LP64todo - not 64bit safe */
  99 struct pipemapping {
 100         vm_offset_t     kva;            /* kernel virtual address */
 101         vm_size_t       cnt;            /* number of chars in buffer */
 102         vm_size_t       pos;            /* current position of transfer */
 103         int             npages;         /* number of pages */
 104         vm_page_t       ms[PIPENPAGES]; /* pages in source process */
 105 };
 106 #endif
 107
 108 /*
 109  * Bits in pipe_state.
 110  */
 111 #define PIPE_ASYNC      0x004   /* Async? I/O. */
 112 #define PIPE_WANTR      0x008   /* Reader wants some characters. */
 113 #define PIPE_WANTW      0x010   /* Writer wants space to put characters. */
 114 #define PIPE_WANT       0x020   /* Pipe is wanted to be run-down. */
 115 #define PIPE_SEL        0x040   /* Pipe has a select active. */
 116 #define PIPE_EOF        0x080   /* Pipe is in EOF condition. */
 117 #define PIPE_LOCKFL     0x100   /* Process has exclusive access to pointers/data. */
 118 #define PIPE_LWANT      0x200   /* Process wants exclusive access to pointers/data. */
 119 #define PIPE_DIRECTW    0x400   /* Pipe direct write active. */
 120 #define PIPE_DIRECTOK   0x800   /* Direct mode ok. */
 121 #define PIPE_KNOTE     0x1000   /* Pipe has kernel events activated */
 122
 123 #ifdef  KERNEL
 124 /*
 125  * Per-pipe data structure.
 126  * Two of these are linked together to produce bi-directional pipes.
 127  */
 128 struct pipe {
 129         struct  pipebuf pipe_buffer;    /* data storage */
 130 #ifdef PIPE_DIRECT
 131         struct  pipemapping pipe_map;   /* pipe mapping for direct I/O */
 132 #endif
 133         struct  selinfo pipe_sel;       /* for compat with select */
 134         pid_t   pipe_pgid;              /* information for async I/O */
 135         struct  pipe *pipe_peer;        /* link with other direction */
 136         u_int   pipe_state;             /* pipe status info */
 137         int     pipe_busy;              /* busy flag, mostly to handle rundown sanely */
 138 #ifdef MAC
 139         struct  label *pipe_label;      /* pipe MAC label - shared */
 140 #endif
 141         TAILQ_HEAD(,eventqelt) pipe_evlist;
 142         lck_mtx_t *pipe_mtxp;           /* shared mutex between both pipes */
 143 };
 144
 145 #define PIPE_MTX(pipe)          ((pipe)->pipe_mtxp)
 146
 147 #define PIPE_LOCK(pipe)         lck_mtx_lock(PIPE_MTX(pipe))
 148 #define PIPE_UNLOCK(pipe)       lck_mtx_unlock(PIPE_MTX(pipe))
 149 #define PIPE_LOCK_ASSERT(pipe, type)  lck_mtx_assert(PIPE_MTX(pipe), (type))
 150
 151 __BEGIN_DECLS
 152 extern int pipe_stat(struct pipe *, struct stat *);
 153 __END_DECLS
 154
 155 #endif  /* KERNEL */
 156
 157 #endif /* !_SYS_PIPE_H_ */