/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 4 -*- */

/* $Id$ */

/* Copyright (C) 1998-99 Martin Baulig
   This file is part of LibGTop 1.0.

   Contributed by Martin Baulig <martin@home-of-linux.org>, April 1998.

   LibGTop 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.

   LibGTop 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 LibGTop; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#include <glibtop.h>
#include <glibtop/global.h>
#include <glibtop/xmalloc.h>

#include <glibtop/backend.h>
#include <glibtop-backend-private.h>

static int
_open_server (glibtop *, glibtop_backend *, u_int64_t, const char **);

static int
_close_server (glibtop *, glibtop_backend *);

extern glibtop_call_vector glibtop_backend_server_call_vector;

glibtop_backend_info glibtop_backend_server = {
    "glibtop-backend-server", _open_server, _close_server,
    &glibtop_backend_server_call_vector
};

static int
_open_server (glibtop *server, glibtop_backend *backend,
	      u_int64_t features, const char **backend_args)
{
    backend->_priv = glibtop_calloc_r
	(server, 1, sizeof (glibtop_backend_private));

    fprintf (stderr, "open_server - %p, %p, %p\n", server, backend,
	     backend->_priv);

    fprintf (stderr, "Opening pipe to server (%s).\n",
	     LIBGTOP_SERVER);

    if (pipe (backend->_priv->input) ||
	pipe (backend->_priv->output)) {
	glibtop_warn_io_r (server, "cannot make a pipe");
	return -1;
    }

    backend->_priv->pid  = fork ();

    if (backend->_priv->pid < 0) {
	glibtop_warn_io_r (server, "fork failed");
	return -1;
    } else if (backend->_priv->pid == 0) {
	close (0); close (1);
	close (backend->_priv->input [0]);
	close (backend->_priv->output [1]);
	dup2 (backend->_priv->input [1], 1);
	dup2 (backend->_priv->output [0], 0);
	execl (LIBGTOP_SERVER, "libgtop-server", NULL);
	glibtop_error_io_r (server, "execl (%s)",
			    LIBGTOP_SERVER);
	_exit (2);
    }

    close (backend->_priv->input [1]);
    close (backend->_priv->output [0]);

    return 0;
}

static int
_close_server (glibtop *server, glibtop_backend *backend)
{
    kill (backend->_priv->pid, SIGKILL);
    close (backend->_priv->input [0]);
    close (backend->_priv->output [1]);

    backend->_priv->pid = 0;

    return 0;
}