gen/FreeBSD/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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)daemon.c    8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/daemon.c,v 1.8 2007/01/09 00:27:53 imp Exp $");
  35
  36 #include "namespace.h"
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <paths.h>
  40 #include <stdlib.h>
  41 #include <signal.h>
  42 #include <unistd.h>
  43 #include "un-namespace.h"
  44
  45 int
  46 daemon(nochdir, noclose)
  47         int nochdir, noclose;
  48 {
  49         struct sigaction osa, sa;
  50         int fd;
  51         pid_t newgrp;
  52         int oerrno;
  53         int osa_ok;
  54
  55         /* A SIGHUP may be thrown when the parent exits below. */
  56         sigemptyset(&sa.sa_mask);
  57         sa.sa_handler = SIG_IGN;
  58         sa.sa_flags = 0;
  59         osa_ok = _sigaction(SIGHUP, &sa, &osa);
  60
  61         switch (fork()) {
  62         case -1:
  63                 return (-1);
  64         case 0:
  65                 break;
  66         default:
  67                 _exit(0);
  68         }
  69
  70         newgrp = setsid();
  71         oerrno = errno;
  72         if (osa_ok != -1)
  73                 _sigaction(SIGHUP, &osa, NULL);
  74
  75         if (newgrp == -1) {
  76                 errno = oerrno;
  77                 return (-1);
  78         }
  79
  80         if (!nochdir)
  81                 (void)chdir("/");
  82
  83         if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
  84                 (void)_dup2(fd, STDIN_FILENO);
  85                 (void)_dup2(fd, STDOUT_FILENO);
  86                 (void)_dup2(fd, STDERR_FILENO);
  87                 if (fd > 2)
  88                         (void)_close(fd);
  89         }
  90         return (0);
  91 }