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_EVENT_H_
  37 #include <sys/event.h>                  /* for struct kqinfo */
  38 #endif
  39 #ifndef _SYS_XIO_H_
  40 #include <sys/xio.h>                    /* for struct xio */
  41 #endif
  42 #ifndef _SYS_THREAD_H_
  43 #include <sys/thread.h>                 /* for struct lwkt_token */
  44 #endif
  45 #ifndef _MACHINE_PARAM_H_
  46 #include <machine/param.h>              /* for PAGE_SIZE */
  47 #endif
  48
  49 /*
  50  * Pipe buffer size, keep moderate in value, pipes take kva space.
  51  * Must be a multiple of PAGE_SIZE.
  52  */
  53 #ifndef PIPE_SIZE
  54 #define PIPE_SIZE       16384
  55 #endif
  56
  57 #ifndef BIG_PIPE_SIZE
  58 #define BIG_PIPE_SIZE   (64*1024)
  59 #endif
  60
  61 #if PIPE_SIZE < PAGE_SIZE
  62 #error "PIPE_SIZE is too small for this architecture"
  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   rindex;         /* FIFO read index */
  72         u_int   dummy1[3];      /* cache-align */
  73         u_int   windex;         /* FIFO write index */
  74         u_int   dummy2[3];      /* cache-align */
  75         u_int   size;           /* size of buffer */
  76         caddr_t buffer;         /* kva of buffer */
  77         struct  vm_object *object;      /* VM object containing buffer */
  78 };
  79
  80 /*
  81  * Bits in pipe_state.
  82  */
  83 #define PIPE_ASYNC      0x0004  /* Async? I/O */
  84 #define PIPE_WANTR      0x0008  /* Reader wants some characters */
  85 #define PIPE_WANTW      0x0010  /* Writer wants space to put characters */
  86 #define PIPE_REOF       0x0040  /* Pipe is in EOF condition (read EOF) */
  87 #define PIPE_WEOF       0x0080  /* Pipe is in EOF condition (write shutdown) */
  88 #define PIPE_CLOSED     0x1000  /* Pipe has been closed */
  89
  90 /*
  91  * Per-pipe data structure.
  92  * Two of these are linked together to produce bi-directional pipes.
  93  */
  94 struct pipe {
  95         struct  pipebuf pipe_buffer;    /* data storage */
  96         struct  kqinfo pipe_kq;         /* for compat with select/poll/kq */
  97         struct  timespec pipe_atime;    /* time of last access */
  98         struct  timespec pipe_mtime;    /* time of last modify */
  99         struct  timespec pipe_ctime;    /* time of status change */
 100         struct  sigio *pipe_sigio;      /* information for async I/O */
 101         struct  pipe *pipe_peer;        /* link with other direction */
 102         u_int   pipe_state;             /* pipe status info */
 103         int     pipe_rip;               /* read uio in-progress */
 104         int     pipe_wip;               /* write uio in-progress */
 105         u_int   pipe_wantwcnt;          /* for resize */
 106         struct  lwkt_token pipe_rlock;  /* rindex locked */
 107         struct  lwkt_token pipe_wlock;  /* windex locked */
 108         struct  lock *pipe_slock;       /* state locked (shared w/peer) */
 109 };
 110
 111 #endif  /* _KERNEL || _KERNEL_STRUCTURES */
 112 #endif /* !_SYS_PIPE_H_ */