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 1.7 2005/03/01 23:35:16 dillon Exp $
  23  */
  24
  25 #ifndef _SYS_PIPE_H_
  26 #define _SYS_PIPE_H_
  27
  28 #ifndef _KERNEL
  29 #include <sys/time.h>                   /* for struct timespec */
  30 #include <sys/select.h>                 /* for struct selinfo */
  31 #include <machine/param.h>              /* for PAGE_SIZE */
  32 #endif
  33
  34 #if !defined(_SYS_XIO_H_)
  35 #include <sys/xio.h>                    /* for struct xio */
  36 #endif
  37
  38 /*
  39  * Pipe buffer size, keep moderate in value, pipes take kva space.
  40  */
  41 #ifndef PIPE_SIZE
  42 #define PIPE_SIZE       16384
  43 #endif
  44
  45 #ifndef BIG_PIPE_SIZE
  46 #define BIG_PIPE_SIZE   (64*1024)
  47 #endif
  48
  49 /*
  50  * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
  51  * than PIPE_BUF.
  52  */
  53 #ifndef PIPE_MINDIRECT
  54 #define PIPE_MINDIRECT  8192
  55 #endif
  56
  57 /*
  58  * Pipe buffer information.
  59  * Separate in, out, cnt are used to simplify calculations.
  60  * Buffered write is active when the buffer.cnt field is set.
  61  */
  62 struct pipebuf {
  63         u_int   cnt;            /* number of chars currently in buffer */
  64         u_int   in;             /* in pointer */
  65         u_int   out;            /* out pointer */
  66         u_int   size;           /* size of buffer */
  67         caddr_t buffer;         /* kva of buffer */
  68         struct  vm_object *object;      /* VM object containing buffer */
  69 };
  70
  71 /*
  72  * Bits in pipe_state.
  73  */
  74 #define PIPE_ASYNC      0x0004  /* Async? I/O. */
  75 #define PIPE_WANTR      0x0008  /* Reader wants some characters. */
  76 #define PIPE_WANTW      0x0010  /* Writer wants space to put characters. */
  77 #define PIPE_WANT       0x0020  /* Pipe is wanted to be run-down. */
  78 #define PIPE_SEL        0x0040  /* Pipe has a select active. */
  79 #define PIPE_EOF        0x0080  /* Pipe is in EOF condition. */
  80 #define PIPE_LOCK       0x0100  /* Process has exclusive access to pointers/data. */
  81 #define PIPE_LWANT      0x0200  /* Process wants exclusive access to pointers/data. */
  82 #define PIPE_DIRECTW    0x0400  /* Pipe direct write active. */
  83 #define PIPE_DIRECTOK   0x0800  /* Direct mode ok. */
  84 #define PIPE_DIRECTIP   0x1000  /* Direct write buffer build in progress */
  85
  86 enum pipe_feature { PIPE_COPY, PIPE_KMEM, PIPE_SFBUF1, PIPE_SFBUF2 };
  87 /*
  88  * Per-pipe data structure.
  89  * Two of these are linked together to produce bi-directional pipes.
  90  *
  91  * NOTE: pipe_buffer.out has the dual purpose of tracking the copy offset
  92  * for both the direct write case (with the rest of pipe_buffer) and the
  93  * buffered write case (with pipe_map).
  94  */
  95 struct pipe {
  96         struct  pipebuf pipe_buffer;    /* data storage */
  97         struct  xio pipe_map;           /* mapping for direct I/O */
  98         vm_offset_t pipe_kva;           /* kva mapping (testing only) */
  99         cpumask_t pipe_kvamask;         /* kva cpu mask opt */
 100         struct  selinfo pipe_sel;       /* for compat with select */
 101         struct  timespec pipe_atime;    /* time of last access */
 102         struct  timespec pipe_mtime;    /* time of last modify */
 103         struct  timespec pipe_ctime;    /* time of status change */
 104         struct  sigio *pipe_sigio;      /* information for async I/O */
 105         struct  pipe *pipe_peer;        /* link with other direction */
 106         u_int   pipe_state;             /* pipe status info */
 107         enum pipe_feature pipe_feature; /* pipe transfer features */
 108         int     pipe_busy;              /* busy flag, mostly to handle rundown sanely */
 109 };
 110
 111 #endif /* !_SYS_PIPE_H_ */