lib/libc/gen/daemon.c

   1 /*      $NetBSD: daemon.c,v 1.9 2003/08/07 16:42:46 agc Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)daemon.c    8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: daemon.c,v 1.9 2003/08/07 16:42:46 agc Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <fcntl.h>
  43 #include <paths.h>
  44 #include <stdlib.h>
  45 #include <unistd.h>
  46
  47 #ifdef __weak_alias
  48 __weak_alias(daemon,_daemon)
  49 #endif
  50
  51 int
  52 daemon(nochdir, noclose)
  53         int nochdir, noclose;
  54 {
  55         int fd;
  56
  57         switch (fork()) {
  58         case -1:
  59                 return (-1);
  60         case 0:
  61                 break;
  62         default:
  63                 _exit(0);
  64         }
  65
  66         if (setsid() == -1)
  67                 return (-1);
  68
  69         if (!nochdir)
  70                 (void)chdir("/");
  71
  72         if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
  73                 (void)dup2(fd, STDIN_FILENO);
  74                 (void)dup2(fd, STDOUT_FILENO);
  75                 (void)dup2(fd, STDERR_FILENO);
  76                 if (fd > STDERR_FILENO)
  77                         (void)close(fd);
  78         }
  79         return (0);
  80 }