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/* $OpenBSD: pipe.h,v 1.27 2020/06/29 18:23:18 anton 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.
*/
#ifndef _SYS_PIPE_H_
#define _SYS_PIPE_H_
#ifndef _KERNEL
#include <sys/time.h> /* for struct timespec */
#include <sys/selinfo.h> /* for struct selinfo */
#endif /* _KERNEL */
#include <sys/sigio.h> /* for struct sigio_ref */
/*
* 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 (64*1024)
#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 {
u_int cnt; /* number of chars currently in buffer */
u_int in; /* in pointer */
u_int out; /* out pointer */
u_int size; /* size of buffer */
caddr_t buffer; /* kva of buffer */
};
/*
* Bits in pipe_state.
*/
#define PIPE_ASYNC 0x004 /* Async? I/O. */
#define PIPE_WANTR 0x008 /* Reader wants some characters. */
#define PIPE_WANTW 0x010 /* Writer wants space to put characters. */
#define PIPE_WANTD 0x020 /* Pipe is wanted to be run-down. */
#define PIPE_SEL 0x040 /* Pipe has a select active. */
#define PIPE_EOF 0x080 /* Pipe is in EOF condition. */
#define PIPE_LOCK 0x100 /* Thread has exclusive I/O access. */
#define PIPE_LWANT 0x200 /* Thread wants exclusive I/O access. */
struct pipe_pair;
/*
* Per-pipe data structure.
* Two of these are linked together to produce bi-directional pipes.
*
* Locking:
* I immutable after creation
* S sigio_lock
* p pipe_lock
*/
struct pipe {
struct rwlock *pipe_lock;
struct pipebuf pipe_buffer; /* [p] data storage */
struct selinfo pipe_sel; /* [p] for compat with select */
struct timespec pipe_atime; /* [p] time of last access */
struct timespec pipe_mtime; /* [p] time of last modify */
struct timespec pipe_ctime; /* [I] time of status change */
struct sigio_ref pipe_sigio; /* [S] async I/O registration */
struct pipe *pipe_peer; /* [p] link with other direction */
struct pipe_pair *pipe_pair; /* [I] pipe storage */
u_int pipe_state; /* [p] pipe status info */
int pipe_busy; /* [p] # readers/writers */
};
#ifdef _KERNEL
void pipe_init(void);
#endif /* _KERNEL */
#endif /* !_SYS_PIPE_H_ */
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