/* $NetBSD: pipe.h,v 1.38 2021/01/25 19:21:11 dholland 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 <sys/time.h> /* for struct timespec */
#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 transfer for direct write transfer. If the amount
* of data in buffer is larger, it would be transferred in chunks of this
* size.
*/
#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 */
};
/*
* 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_LOCKFL 0x100 /* Process has exclusive access to
pointers/data. */
/* unused 0x200 */
#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 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 */
u_int pipe_waiters; /* number of waiters pending */
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 (obsolete) */
#define KERN_PIPE_LIMITKVA 2 /* limit kva for laons (obsolete) */
#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 */
#ifdef _KERNEL
int sysctl_dopipe(int *, u_int, void *, size_t *, void *, size_t);
void pipe_init(void);
#endif /* _KERNEL */
#endif /* !_SYS_PIPE_H_ */