sys/sys/pipe.h

   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: src/sys/sys/pipe.h,v 1.16 1999/12/29 04:24:45 peter Exp $
  22  * $DragonFly: src/sys/sys/pipe.h,v 1.10 2006/06/10 20:00:17 dillon Exp $
  23  */
  24
  25 #ifndef _SYS_PIPE_H_
  26 #define _SYS_PIPE_H_
  27
  28 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  29
  30 #ifndef _SYS_TYPES_H_
  31 #include <sys/types.h>
  32 #endif
  33 #ifndef _SYS_TIME_H_
  34 #include <sys/time.h>                   /* for struct timespec */
  35 #endif
  36 #ifndef _SYS_SELINFO_H_
  37 #include <sys/selinfo.h>                /* for struct selinfo */
  38 #endif
  39 #ifndef _SYS_XIO_H_
  40 #include <sys/xio.h>                    /* for struct xio */
  41 #endif
  42 #ifndef _MACHINE_PARAM_H_
  43 #include <machine/param.h>              /* for PAGE_SIZE */
  44 #endif
  45
  46 /*
  47  * Pipe buffer size, keep moderate in value, pipes take kva space.
  48  */
  49 #ifndef PIPE_SIZE
  50 #define PIPE_SIZE       16384
  51 #endif
  52
  53 #ifndef BIG_PIPE_SIZE
  54 #define BIG_PIPE_SIZE   (64*1024)
  55 #endif
  56
  57 /*
  58  * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
  59  * than PIPE_BUF.
  60  */
  61 #ifndef PIPE_MINDIRECT
  62 #define PIPE_MINDIRECT  8192
  63 #endif
  64
  65 /*
  66  * Pipe buffer information.
  67  * Separate in, out, cnt are used to simplify calculations.
  68  * Buffered write is active when the buffer.cnt field is set.
  69  */
  70 struct pipebuf {
  71         u_int   cnt;            /* number of chars currently in buffer */
  72         u_int   in;             /* in pointer */
  73         u_int   out;            /* out pointer */
  74         u_int   size;           /* size of buffer */
  75         caddr_t buffer;         /* kva of buffer */
  76         struct  vm_object *object;      /* VM object containing buffer */
  77 };
  78
  79 /*
  80  * Bits in pipe_state.
  81  */
  82 #define PIPE_ASYNC      0x0004  /* Async? I/O. */
  83 #define PIPE_WANTR      0x0008  /* Reader wants some characters. */
  84 #define PIPE_WANTW      0x0010  /* Writer wants space to put characters. */
  85 #define PIPE_WANT       0x0020  /* Pipe is wanted to be run-down. */
  86 #define PIPE_SEL        0x0040  /* Pipe has a select active. */
  87 #define PIPE_EOF        0x0080  /* Pipe is in EOF condition. */
  88 #define PIPE_LOCK       0x0100  /* Process has exclusive access to pointers/data. */
  89 #define PIPE_LWANT      0x0200  /* Process wants exclusive access to pointers/data. */
  90 #define PIPE_DIRECTW    0x0400  /* Pipe direct write active. */
  91 #define PIPE_DIRECTOK   0x0800  /* Direct mode ok. */
  92 #define PIPE_DIRECTIP   0x1000  /* Direct write buffer build in progress */
  93
  94 enum pipe_feature { PIPE_COPY, PIPE_KMEM, PIPE_SFBUF1, PIPE_SFBUF2 };
  95 /*
  96  * Per-pipe data structure.
  97  * Two of these are linked together to produce bi-directional pipes.
  98  *
  99  * NOTE: pipe_buffer.out has the dual purpose of tracking the copy offset
 100  * for both the direct write case (with the rest of pipe_buffer) and the
 101  * buffered write case (with pipe_map).
 102  */
 103 struct pipe {
 104         struct  pipebuf pipe_buffer;    /* data storage */
 105         struct  xio pipe_map;           /* mapping for direct I/O */
 106         vm_offset_t pipe_kva;           /* kva mapping (testing only) */
 107         cpumask_t pipe_kvamask;         /* kva cpu mask opt */
 108         struct  selinfo pipe_sel;       /* for compat with select */
 109         struct  timespec pipe_atime;    /* time of last access */
 110         struct  timespec pipe_mtime;    /* time of last modify */
 111         struct  timespec pipe_ctime;    /* time of status change */
 112         struct  sigio *pipe_sigio;      /* information for async I/O */
 113         struct  pipe *pipe_peer;        /* link with other direction */
 114         u_int   pipe_state;             /* pipe status info */
 115         enum pipe_feature pipe_feature; /* pipe transfer features */
 116         int     pipe_busy;              /* busy flag, mostly to handle rundown sanely */
 117 };
 118
 119 #endif  /* _KERNEL || _KERNEL_STRUCTURES */
 120 #endif /* !_SYS_PIPE_H_ */