bsd/sys/pipe.h

   1 /*
   2  * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1996 John S. Dyson
  30  * All rights reserved.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice immediately at the beginning of the file, without modification,
  37  *    this list of conditions, and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. Absolutely no warranty of function or purpose is made by the author
  42  *    John S. Dyson.
  43  * 4. This work was done expressly for inclusion into FreeBSD.  Other use
  44  *    is allowed if this notation is included.
  45  * 5. Modifications may be freely made to this file if the above conditions
  46  *    are met.
  47  *
  48  * $FreeBSD: src/sys/sys/pipe.h,v 1.24 2003/08/13 20:01:38 alc Exp $
  49  */
  50
  51 #ifndef _SYS_PIPE_H_
  52 #define _SYS_PIPE_H_
  53
  54 #ifdef  KERNEL
  55 #include <libkern/locks.h>
  56 #endif
  57 #include <sys/queue.h>                  /* for TAILQ macros */
  58 #include <sys/ev.h>
  59 #include <sys/cdefs.h>
  60
  61 /*
  62  * Pipe buffer size, keep moderate in value, pipes take kva space.
  63  */
  64 #ifndef PIPE_SIZE
  65 #define PIPE_SIZE       16384
  66 #endif
  67
  68 #ifndef BIG_PIPE_SIZE
  69 #define BIG_PIPE_SIZE   (64*1024)
  70 #endif
  71
  72 #ifndef SMALL_PIPE_SIZE
  73 #define SMALL_PIPE_SIZE PAGE_SIZE
  74 #endif
  75
  76 /*
  77  * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
  78  * than PIPE_BUF.
  79  */
  80 #ifndef PIPE_MINDIRECT
  81 #define PIPE_MINDIRECT  8192
  82 #endif
  83
  84 #define PIPENPAGES      (BIG_PIPE_SIZE / PAGE_SIZE + 1)
  85
  86 /*
  87  * Pipe buffer information.
  88  * Separate in, out, cnt are used to simplify calculations.
  89  * Buffered write is active when the buffer.cnt field is set.
  90  */
  91 struct pipebuf {
  92         u_int   cnt;            /* number of chars currently in buffer */
  93         u_int   in;             /* in pointer */
  94         u_int   out;            /* out pointer */
  95         u_int   size;           /* size of buffer */
  96         caddr_t buffer;         /* kva of buffer */
  97 };
  98
  99
 100 #ifdef PIPE_DIRECT
 101 /*
 102  * Information to support direct transfers between processes for pipes.
 103  */
 104 /* LP64todo - not 64bit safe */
 105 struct pipemapping {
 106         vm_offset_t     kva;            /* kernel virtual address */
 107         vm_size_t       cnt;            /* number of chars in buffer */
 108         vm_size_t       pos;            /* current position of transfer */
 109         int             npages;         /* number of pages */
 110         vm_page_t       ms[PIPENPAGES]; /* pages in source process */
 111 };
 112 #endif
 113
 114 /*
 115  * Bits in pipe_state.
 116  */
 117 #define PIPE_ASYNC      0x004   /* Async? I/O. */
 118 #define PIPE_WANTR      0x008   /* Reader wants some characters. */
 119 #define PIPE_WANTW      0x010   /* Writer wants space to put characters. */
 120 #define PIPE_WANT       0x020   /* Pipe is wanted to be run-down. */
 121 #define PIPE_SEL        0x040   /* Pipe has a select active. */
 122 #define PIPE_EOF        0x080   /* Pipe is in EOF condition. */
 123 #define PIPE_LOCKFL     0x100   /* Process has exclusive access to pointers/data. */
 124 #define PIPE_LWANT      0x200   /* Process wants exclusive access to pointers/data. */
 125 #define PIPE_DIRECTW    0x400   /* Pipe direct write active. */
 126 #define PIPE_DIRECTOK   0x800   /* Direct mode ok. */
 127 #define PIPE_KNOTE     0x1000   /* Pipe has kernel events activated */
 128
 129 #ifdef  KERNEL
 130 /*
 131  * Per-pipe data structure.
 132  * Two of these are linked together to produce bi-directional pipes.
 133  */
 134 struct pipe {
 135         struct  pipebuf pipe_buffer;    /* data storage */
 136 #ifdef PIPE_DIRECT
 137         struct  pipemapping pipe_map;   /* pipe mapping for direct I/O */
 138 #endif
 139         struct  selinfo pipe_sel;       /* for compat with select */
 140         pid_t   pipe_pgid;              /* information for async I/O */
 141         struct  pipe *pipe_peer;        /* link with other direction */
 142         u_int   pipe_state;             /* pipe status info */
 143         int     pipe_busy;              /* busy flag, mostly to handle rundown sanely */
 144 #ifdef MAC
 145         struct  label *pipe_label;      /* pipe MAC label - shared */
 146 #endif
 147         TAILQ_HEAD(,eventqelt) pipe_evlist;
 148         lck_mtx_t *pipe_mtxp;           /* shared mutex between both pipes */
 149 };
 150
 151 #define PIPE_MTX(pipe)          ((pipe)->pipe_mtxp)
 152
 153 #define PIPE_LOCK(pipe)         lck_mtx_lock(PIPE_MTX(pipe))
 154 #define PIPE_UNLOCK(pipe)       lck_mtx_unlock(PIPE_MTX(pipe))
 155 #define PIPE_LOCK_ASSERT(pipe, type)  lck_mtx_assert(PIPE_MTX(pipe), (type))
 156
 157 __BEGIN_DECLS
 158 extern int pipe_stat(struct pipe *, struct stat *);
 159 __END_DECLS
 160
 161 #endif  /* KERNEL */
 162
 163 #endif /* !_SYS_PIPE_H_ */