/*
 * The Qubes OS Project, http://www.qubes-os.org
 *
 * Copyright (C) 2010  Rafal Wojtczuk  <rafal@xxxxxxxxxxxxxxxxxxxxxx>
 *
 * 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
 * of the License, 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#include <stdint.h>
#include <sys/types.h>
typedef uint32_t VCHAN_RING_IDX;

/// struct vchan_interface is placed in memory shared between domains
struct vchan_interface {
        // One buffer for each data direction
	char buf_in[1024];
	char buf_out[2048];
	// standard consumer/producer interface, one pair per buffer
	VCHAN_RING_IDX cons_in, prod_in, cons_out, prod_out;
	uint32_t debug;
	int client_closed, server_closed;
};
/// struct libvchan is a control structure, passed to all library calls
struct libvchan {
	// person we communicate with
	int other_domain_id;
	// "port" we communicate on (allows multiple vchans to exist)
	int device_number;
	// Shared ring page, its kernel FD, and its grant reference
	struct vchan_interface *ring;
	int ring_fd;
	uint32_t ring_ref;
	// event channel interface
	int event_fd;
	int event_port;
	// boolean controlling read/write locations
	int is_server;
};

struct libvchan *libvchan_server_init(int domain, int devno);
struct libvchan *libvchan_client_init(int domain, int devno);

// reads exactly size or aborts
int libvchan_recv(struct libvchan *ctrl, void *data, size_t size);
// reads up to size bytes (including zero) without blocking
int libvchan_read(struct libvchan *ctrl, void *data, size_t size);
// sends entire buffer or aborts
int libvchan_send(struct libvchan *ctrl, const void *data, size_t size);
// sends as much data as possible without blocking
int libvchan_write(struct libvchan *ctrl, const void *data, size_t size);
// waits for reads or writes to unblock
int libvchan_wait(struct libvchan *ctrl);
int libvchan_close(struct libvchan *ctrl);
// (only) when this FD is readable, libvchan_wait() will not block
int libvchan_fd_for_select(struct libvchan *ctrl);
int libvchan_is_eof(struct libvchan *ctrl);
int libvchan_data_ready(struct libvchan *ctrl);
int libvchan_buffer_space(struct libvchan *ctrl);