lib/daemon.c

   1 /*
   2  * Daemonize routine
   3  * Copyright (C) 1997, 1999 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation; either version 2, or (at your
  10  * option) any later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include <zebra.h>
  24 #include <log.h>
  25
  26 #ifndef HAVE_DAEMON
  27
  28 /* Daemonize myself. */
  29 int
  30 daemon (int nochdir, int noclose)
  31 {
  32   pid_t pid;
  33
  34   pid = fork ();
  35
  36   /* In case of fork is error. */
  37   if (pid < 0)
  38     {
  39       zlog_err ("fork failed: %s", safe_strerror(errno));
  40       return -1;
  41     }
  42
  43   /* In case of this is parent process. */
  44   if (pid != 0)
  45     exit (0);
  46
  47   /* Become session leader and get pid. */
  48   pid = setsid();
  49
  50   if (pid == -1)
  51     {
  52       zlog_err ("setsid failed: %s", safe_strerror(errno));
  53       return -1;
  54     }
  55
  56   /* Change directory to root. */
  57   if (! nochdir)
  58     chdir ("/");
  59
  60   /* File descriptor close. */
  61   if (! noclose)
  62     {
  63       int fd;
  64
  65       fd = open ("/dev/null", O_RDWR, 0);
  66       if (fd != -1)
  67         {
  68           dup2 (fd, STDIN_FILENO);
  69           dup2 (fd, STDOUT_FILENO);
  70           dup2 (fd, STDERR_FILENO);
  71           if (fd > 2)
  72             close (fd);
  73         }
  74     }
  75
  76   umask (0027);
  77
  78   return 0;
  79 }
  80
  81 #endif /* HAVE_DAEMON */