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/*
Copyright (C) 1993, 1994, 1996 Free Software Foundation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifndef _HURD_IOHELP_
#define _HURD_IOHELP_
#include <mach.h>
#include <hurd/hurd_types.h>
#include <cthreads.h>
#include <hurd/shared.h>
/* Conch manipulation. */
struct conch
{
struct mutex *lock;
struct condition wait;
void *holder;
struct shared_io *holder_shared_page;
};
/* Initialize a conch box */
void iohelp_initialize_conch (struct conch *, struct mutex *);
/* These routines are not reentrant. The server is responsible
for ensuring that all calls to these routines are serialized
by locking the lock passed to initialize_conch. */
/* Handle a user request to obtain the conch (io_get_conch) */
void iohelp_handle_io_get_conch (struct conch *, void *,
struct shared_io *);
/* Obtain the conch for the server */
void iohelp_get_conch (struct conch *);
/* Handle a user request to release the conch (io_release_conch). */
void iohelp_handle_io_release_conch (struct conch *, void *);
/* Check if the user is allowed to make a shared-data notification
message. */
error_t iohelp_verify_user_conch (struct conch *, void *);
/* This function must by defined by the server. It should transfer
information from the current conch holder's shared page to the server's
data (the arg is the conch owner). */
void iohelp_fetch_shared_data (void *);
/* This function must be defined by the server. It should transfer
information from the server's data to the current conch holder's
shared page (the arg is the conch owner). */
void iohelp_put_shared_data (void *);
#endif
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