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/*
* 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.
*
* $FreeBSD$
*/
#ifndef _SYS_PIPE_H_
#define _SYS_PIPE_H_
#ifndef _KERNEL
#error "no user-servicable parts inside"
#endif
/*
* 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
#ifndef SMALL_PIPE_SIZE
#define SMALL_PIPE_SIZE PAGE_SIZE
#endif
/*
* PIPE_MINDIRECT MUST be smaller than PIPE_SIZE and MUST be bigger
* than PIPE_BUF.
*/
#ifndef PIPE_MINDIRECT
#define PIPE_MINDIRECT 8192
#endif
#define PIPENPAGES (BIG_PIPE_SIZE / PAGE_SIZE + 1)
/*
* See sys_pipe.c for info on what these limits mean.
*/
extern int maxpipekva;
/*
* 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 */
};
/*
* Information to support direct transfers between processes for pipes.
*/
struct pipemapping {
vm_size_t cnt; /* number of chars in buffer */
vm_size_t pos; /* current position of transfer */
int npages; /* number of pages */
vm_page_t ms[PIPENPAGES]; /* pages in source process */
};
/*
* 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_WANT 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_LOCKFL 0x100 /* Process has exclusive access to pointers/data. */
#define PIPE_LWANT 0x200 /* Process wants exclusive access to pointers/data. */
#define PIPE_DIRECTW 0x400 /* Pipe direct write active. */
#define PIPE_DIRECTOK 0x800 /* Direct mode ok. */
/*
* Per-pipe data structure.
* Two of these are linked together to produce bi-directional pipes.
*/
struct pipe {
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_ctime; /* time of status change */
struct sigio *pipe_sigio; /* information for async I/O */
struct pipe *pipe_peer; /* link with other direction */
struct pipepair *pipe_pair; /* container structure pointer */
u_int pipe_state; /* pipe status info */
int pipe_busy; /* busy flag, mostly to handle rundown sanely */
int pipe_present; /* still present? */
};
/*
* Container structure to hold the two pipe endpoints, mutex, and label
* pointer.
*/
struct pipepair {
struct pipe pp_rpipe;
struct pipe pp_wpipe;
struct mtx pp_mtx;
struct label *pp_label;
};
#define PIPE_MTX(pipe) (&(pipe)->pipe_pair->pp_mtx)
#define PIPE_LOCK(pipe) mtx_lock(PIPE_MTX(pipe))
#define PIPE_UNLOCK(pipe) mtx_unlock(PIPE_MTX(pipe))
#define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type))
#endif /* !_SYS_PIPE_H_ */
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