mdw@git.distorted.org.uk Git - mLib/blob - daemonize.c

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Become a daemon, detaching from terminals
   6  *
   7  * (c) 2007 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the mLib utilities library.
  13  *
  14  * mLib is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * mLib is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with mLib; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <sys/types.h>
  33 #include <unistd.h>
  34 #include <fcntl.h>
  35 #include <sys/ioctl.h>
  36
  37 #include "daemonize.h"
  38
  39 /*----- Main code ---------------------------------------------------------*/
  40
  41 /* --- @detachtty@ --- *
  42  *
  43  * Arguments:   ---
  44  *
  45  * Returns:     ---
  46  *
  47  * Use:         Detaches from the current terminal and ensures it can never
  48  *              acquire a new one.  Calls @fork@.
  49  */
  50
  51 void detachtty(void)
  52 {
  53 #ifdef TIOCNOTTY
  54   {
  55     int fd;
  56     if ((fd = open("/dev/tty", O_RDONLY)) >= 0) {
  57       ioctl(fd, TIOCNOTTY);
  58       close(fd);
  59     }
  60   }
  61 #endif
  62   setsid();
  63   if (fork() > 0)
  64     _exit(0);
  65 }
  66
  67 /* --- @daemonize@ --- *
  68  *
  69  * Arguments:   ---
  70  *
  71  * Returns:     Zero if OK, nonzero on failure.
  72  *
  73  * Use:         Becomes a daemon.
  74  */
  75
  76 int daemonize(void)
  77 {
  78   pid_t kid;
  79
  80   if ((kid = fork()) < 0)
  81     return (-1);
  82   if (kid)
  83     _exit(0);
  84   detachtty();
  85   return (0);
  86 }
  87
  88 /*----- That's all, folks -------------------------------------------------*/