1 /*-
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33 
  34 #include "k5-int.h"
  35 #include <fcntl.h>
  36 #include <sys/types.h>
  37 #include <sys/file.h>
  38 #include <unistd.h>
  39 #ifdef HAVE_PATHS_H
  40 #include <paths.h>
  41 #endif
  42 
  43 #ifndef _PATH_DEVNULL
  44 #define _PATH_DEVNULL "/dev/null"
  45 #endif
  46 
  47 int
  48 daemon(nochdir, noclose)
  49         int nochdir, noclose;
  50 {
  51         int cpid;
  52 
  53         if ((cpid = fork()) == -1)
  54                 return (-1);
  55         if (cpid)
  56                 exit(0);
  57 #ifdef HAVE_SETSID
  58         (void) setsid();
  59 #else
  60 #ifndef TIOCNOTTY
  61         setpgrp();
  62 #else
  63         {
  64                 int n;
  65             
  66                 /*
  67                  * The open below may hang on pseudo ttys if the person
  68                  * who starts named logs out before this point.  Thus,
  69                  * the need for the timer.
  70                  */
  71                 alarm(120);
  72                 n = open("/dev/tty", O_RDWR);
  73                 alarm(0);
  74                 if (n > 0) {
  75                         (void) ioctl(n, TIOCNOTTY, (char *)NULL);
  76                         (void) close(n);
  77                 }
  78         }
  79 #endif
  80 #endif
  81         if (!nochdir)
  82                 (void) chdir("/");
  83         if (!noclose) {
  84                 int devnull = open(_PATH_DEVNULL, O_RDWR, 0);
  85 
  86                 if (devnull != -1) {
  87                         (void) dup2(devnull, 0);
  88                         (void) dup2(devnull, 1);
  89                         (void) dup2(devnull, 2);
  90                         if (devnull > 2)
  91                                 (void) close(devnull);
  92                 }
  93         }
  94         return (0);
  95 }