LCOM1920-T02G10

/* $NetBSD: pipe.h,v 1.32 2009/12/20 09:36:06 dsl Exp $ */

/*

 * Copyright (c) 1996 John S. Dyson

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice immediately at the beginning of the file, without modification,

 *    this list of conditions, and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Absolutely no warranty of function or purpose is made by the author

 *    John S. Dyson.

 * 4. This work was done expressly for inclusion into FreeBSD.  Other use

 *    is allowed if this notation is included.

 * 5. Modifications may be freely made to this file if the above conditions

 *    are met.

 *

 * $FreeBSD: src/sys/sys/pipe.h,v 1.18 2002/02/27 07:35:59 alfred Exp $

 */

#ifndef _SYS_PIPE_H_

#define _SYS_PIPE_H_

#include <sys/selinfo.h>                /* for struct selinfo */

#include <uvm/uvm_extern.h>

/*

 * Pipe buffer size, keep moderate in value, pipes take kva space.

 */

#ifndef PIPE_SIZE

#define PIPE_SIZE        16384

#endif

#ifndef BIG_PIPE_SIZE

#define BIG_PIPE_SIZE        (4*PIPE_SIZE)

#endif

/*

 * Maximum size of kva for direct write transfer. If the amount

 * of data in buffer is larger, it would be transferred in chunks of this

 * size. This kva memory is freed after use if amount of pipe kva memory

 * is bigger than limitpipekva.

 */

#ifndef PIPE_DIRECT_CHUNK

#define PIPE_DIRECT_CHUNK        (1*1024*1024)

#endif

/*

 * PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger

 * than PIPE_BUF.

 */

#ifndef PIPE_MINDIRECT

#define PIPE_MINDIRECT        8192

#endif

/*

 * Pipe buffer information.

 * Separate in, out, cnt are used to simplify calculations.

 * Buffered write is active when the buffer.cnt field is set.

 */

struct pipebuf {

        size_t        cnt;                /* number of chars currently in buffer */

        u_int        in;                /* in pointer */

        u_int        out;                /* out pointer */

        size_t        size;                /* size of buffer */

        void *        buffer;                /* kva of buffer */

};

/*

 * Information to support direct transfers between processes for pipes.

 */

struct pipemapping {

        vaddr_t                kva;                /* kernel virtual address */

        vsize_t                cnt;                /* number of chars in buffer */

        voff_t                pos;                /* current position within page */

        int                npages;                /* how many pages allocated */

        struct vm_page        **pgs;                /* pointers to the pages */

        u_int                egen;                /* emap generation number */

};

/*

 * Bits in pipe_state.

 */

#define PIPE_ASYNC        0x001        /* Async I/O */

#define PIPE_EOF        0x010        /* Pipe is in EOF condition */

#define PIPE_SIGNALR        0x020        /* Do selwakeup() on read(2) */

#define PIPE_DIRECTW        0x040        /* Pipe in direct write mode setup */

#define PIPE_DIRECTR        0x080        /* Pipe direct read request (setup complete) */

#define        PIPE_LOCKFL        0x100        /* Process has exclusive access to

                                   pointers/data. */

#define        PIPE_LWANT        0x200        /* Process wants exclusive access to

                                   pointers/data. */

#define        PIPE_RESTART        0x400        /* Return ERESTART to blocked syscalls */

/*

 * Per-pipe data structure.

 * Two of these are linked together to produce bi-directional pipes.

 */

struct pipe {

        kmutex_t *pipe_lock;                /* pipe mutex */

        kcondvar_t pipe_rcv;                /* cv for readers */

        kcondvar_t pipe_wcv;                /* cv for writers */

        kcondvar_t pipe_draincv;        /* cv for close */

        kcondvar_t pipe_lkcv;                /* locking */

        struct        pipebuf pipe_buffer;        /* data storage */

        struct        pipemapping pipe_map;        /* pipe mapping for direct I/O */

        struct        selinfo pipe_sel;        /* for compat with select */

        struct        timespec pipe_atime;        /* time of last access */

        struct        timespec pipe_mtime;        /* time of last modify */

        struct        timespec pipe_btime;        /* time of creation */

        pid_t        pipe_pgid;                /* process group for sigio */

        struct        pipe *pipe_peer;        /* link with other direction */

        u_int        pipe_state;                /* pipe status info */

        int        pipe_busy;                /* busy flag, to handle rundown */

        vaddr_t        pipe_kmem;                /* preallocated PIPE_SIZE buffer */

};

/*

 * KERN_PIPE subtypes

 */

#define        KERN_PIPE_MAXKVASZ                1        /* maximum kva size */

#define        KERN_PIPE_LIMITKVA                2        /* */

#define        KERN_PIPE_MAXBIGPIPES                3        /* maximum # of "big" pipes */

#define        KERN_PIPE_NBIGPIPES                4        /* current number of "big" p. */

#define        KERN_PIPE_KVASIZE                5        /* current pipe kva size */

#define        KERN_PIPE_MAXID                        6

#define        CTL_PIPE_NAMES { \

        { 0, 0 }, \

        { "maxkvasz", CTLTYPE_INT }, \

        { "maxloankvasz", CTLTYPE_INT }, \

        { "maxbigpipes", CTLTYPE_INT }, \

        { "nbigpipes", CTLTYPE_INT }, \

        { "kvasize", CTLTYPE_INT }, \

}

#ifdef _KERNEL

int        sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t);

void        pipe_init(void);

#endif /* _KERNEL */

#endif /* !_SYS_PIPE_H_ */