lib/libc/gen/daemon.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  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  * $FreeBSD: src/lib/libc/gen/daemon.c,v 1.3 2000/01/27 23:06:14 jasone Exp $
  34  * $DragonFly: src/lib/libc/gen/daemon.c,v 1.4 2005/04/26 15:57:39 joerg Exp $
  35  *
  36  * @(#)daemon.c 8.1 (Berkeley) 6/4/93
  37  */
  38
  39 #include "namespace.h"
  40 #include <fcntl.h>
  41 #include <paths.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44 #include "un-namespace.h"
  45
  46 int
  47 daemon(int nochdir, int noclose)
  48 {
  49         int fd;
  50
  51         switch (fork()) {
  52         case -1:
  53                 return (-1);
  54         case 0:
  55                 break;
  56         default:
  57                 _exit(0);
  58         }
  59
  60         if (setsid() == -1)
  61                 return (-1);
  62
  63         if (!nochdir)
  64                 chdir("/");
  65
  66         if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
  67                 _dup2(fd, STDIN_FILENO);
  68                 _dup2(fd, STDOUT_FILENO);
  69                 _dup2(fd, STDERR_FILENO);
  70                 if (fd > 2)
  71                         _close(fd);
  72         }
  73         return (0);
  74 }