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

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