source: trunk/third/libgtop/lib/open.c @ 20897

/* $Id: open.c,v 1.1.1.2 2004-10-03 05:00:40 ghudson Exp $ */

/* 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/open.h>
#include <glibtop/version.h>
#include <glibtop/sysdeps.h>
#include <glibtop/command.h>

#include <glibtop/gnuserv.h>

/* Opens pipe to gtop server. Returns 0 on success and -1 on error. */

void
glibtop_open_l (glibtop *server, const char *program_name,
                const unsigned long features, const unsigned flags)
{
        int connect_type;

        server->name = program_name;

        /* It is important to set _GLIBTOP_INIT_STATE_OPEN here when we
         * do recursive calls to glibtop_init_r (). */

        server->flags |= _GLIBTOP_INIT_STATE_OPEN;

        server->error_method = GLIBTOP_ERROR_METHOD_DEFAULT;

#ifdef DEBUG
        fprintf (stderr, "SIZEOF: %u - %u - %u - %u - %u - %u\n",
                 sizeof (glibtop_command), sizeof (glibtop_response),
                 sizeof (glibtop_mountentry), sizeof (glibtop_union),
                 sizeof (glibtop_sysdeps), sizeof (glibtop_response_union));
#endif

        switch (server->method) {
        case GLIBTOP_METHOD_DIRECT:
                server->features = 0;
                break;
        case GLIBTOP_METHOD_INET:
#ifdef DEBUG
                fprintf (stderr, "Connecting to '%s' port %ld.\n",
                         server->server_host, server->server_port);
#endif

                connect_type = glibtop_make_connection
                        (server->server_host, server->server_port,
                         &server->socket);

#ifdef DEBUG
                fprintf (stderr, "Connect Type is %d.\n", connect_type);
#endif

                server->flags |= _GLIBTOP_INIT_STATE_SERVER;

                server->features = -1;
                break;
        case GLIBTOP_METHOD_UNIX:
#ifdef DEBUG
                fprintf (stderr, "Connecting to Unix Domain Socket.\n");
#endif

                connect_type = glibtop_make_connection
                        ("unix", 0, &server->socket);

#ifdef DEBUG
                fprintf (stderr, "Connect Type is %d.\n", connect_type);
#endif

                server->flags |= _GLIBTOP_INIT_STATE_SERVER;

                server->features = -1;
                break;
        case GLIBTOP_METHOD_PIPE:
#ifdef DEBUG
                fprintf (stderr, "Opening pipe to server (%s).\n",
                         LIBGTOP_SERVER);
#endif

                if (pipe (server->input) || pipe (server->output))
                        glibtop_error_io_r (server, "cannot make a pipe");

                server->pid  = fork ();

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

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

                server->flags |= _GLIBTOP_INIT_STATE_SERVER;

                server->features = -1;
                break;
        }

        /* If the server has been started, ask it for its features. */

        if (server->flags & _GLIBTOP_INIT_STATE_SERVER) {
                char version [BUFSIZ], buffer [BUFSIZ];
                glibtop_sysdeps sysdeps;
                size_t size, nbytes;

                /* First check whether the server version is correct. */

                sprintf (version, LIBGTOP_VERSION_STRING,
                         LIBGTOP_VERSION, LIBGTOP_SERVER_VERSION,
                         sizeof (glibtop_command),
                         sizeof (glibtop_response),
                         sizeof (glibtop_union),
                         sizeof (glibtop_sysdeps));

                size = strlen (version) + 1;

                glibtop_read_l (server, sizeof (nbytes), &nbytes);

                if (nbytes != size)
                        glibtop_error_r (server,
                                         "Requested %u bytes but got %u.",
                                         size, nbytes);

                glibtop_read_l (server, nbytes, buffer);

                if (memcmp (version, buffer, size))
                        glibtop_error_r (server, "server version is not %s",
                                         LIBGTOP_VERSION);

                /* Now ask it for its features. */

                glibtop_call_l (server, GLIBTOP_CMND_SYSDEPS, 0, NULL,
                                sizeof (glibtop_sysdeps), &sysdeps);

                server->features = sysdeps.features;

                memcpy (&server->sysdeps, &sysdeps, sizeof (glibtop_sysdeps));

#ifdef DEBUG
                fprintf (stderr, "Server features are %lu.\n",
                         server->features);
#endif
        }

        /* In any case, we call the open functions of our own sysdeps
         * directory. */

#ifdef DEBUG
        fprintf (stderr, "Calling sysdeps open function.\n");
#endif

        glibtop_init_s (&server, features, flags);
}