daemon.c

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/*
 * static char *rcsid_daemon_c =
 *   "$Id: daemon.c 11578 2009-02-23 22:02:27Z lalo $";
 */

/*
    CrossFire, A Multiplayer game for X-windows

    Copyright (C) 2002 Mark Wedel & Crossfire Development Team
    Copyright (C) 1992 Frank Tore Johansen

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

    The author can be reached via e-mail to crossfire-devel@real-time.com
*/

#include <global.h>
#ifndef __CEXTRACT__
#include <sproto.h>
#endif
#include <sys/ioctl.h>
#ifdef hpux
#include <sys/ptyio.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <sys/file.h>

void become_daemon(void) {
    register int i;
    int forkresult;

    fputs("\n========================\n", logfile);
    fputs("Begin New Server Session\n", logfile);
    fputs("========================\n\n", logfile);
    /*
     * fork so that the process goes into the background automatically. Also
     * has a nice side effect of having the child process get inherited by
     * init (pid 1).
     */

    if ((forkresult = fork())) {   /* if parent */
        if (forkresult < 0) {
            perror("Fork error!");
        }
        exit(0);    /* then no more work to do */
    }

    /*
     * Close standard file descriptors and get rid of controlling tty
     */

    close(0);
    close(1);
    close(2);

    /*
     * Set up the standard file descriptors.
     */
    (void)open("/dev/null", O_RDONLY);  /* root inode already in core */
    (void)dup2(0, 1);
    (void)dup2(0, 2);

    if ((i = open("/dev/tty", O_RDWR)) >= 0) {  /* did open succeed? */
#if (defined(SYSV) || defined(hpux)) && defined(TIOCTTY)
        int zero = 0;
        (void)ioctl(i, TIOCTTY, &zero);
#else

#  ifdef HAVE_SYS_TERMIOS_H
#    include <sys/termios.h>
#  else
#    ifdef HAVE_SYS_TTYCOM_H
#      include <sys/ttycom.h>
#    endif
#  endif
        (void)ioctl(i, TIOCNOTTY, (char *)0);     /* detach, BSD style */
#endif
        (void)close(i);
    }

#ifdef HAVE_SETSID
    setsid();
#else
    /* Are these really different?  */
#  if defined(SYSV) || defined(SVR4)
    setpgrp(0, 0);
#  else /* Non SYSV machines */
    setpgrp(0, getpid());
#  endif
#endif
}