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  * 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 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)daemon.c    8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD: src/lib/libc/gen/daemon.c,v 1.6 2003/11/10 22:01:42 ghelmer Exp $");
  39
  40 #include "namespace.h"
  41 #include <errno.h>
  42 #include <fcntl.h>
  43 #include <paths.h>
  44 #include <signal.h>
  45 #include <unistd.h>
  46 #include "un-namespace.h"
  47
  48 int
  49 daemon(nochdir, noclose)
  50         int nochdir, noclose;
  51 {
  52         struct sigaction osa, sa;
  53         int fd;
  54         pid_t newgrp;
  55         int oerrno;
  56         int osa_ok;
  57
  58         /* A SIGHUP may be thrown when the parent exits below. */
  59         sigemptyset(&sa.sa_mask);
  60         sa.sa_handler = SIG_IGN;
  61         sa.sa_flags = 0;
  62         osa_ok = _sigaction(SIGHUP, &sa, &osa);
  63
  64         switch (fork()) {
  65         case -1:
  66                 return (-1);
  67         case 0:
  68                 break;
  69         default:
  70                 _exit(0);
  71         }
  72
  73         newgrp = setsid();
  74         oerrno = errno;
  75         if (osa_ok != -1)
  76                 _sigaction(SIGHUP, &osa, NULL);
  77
  78         if (newgrp == -1) {
  79                 errno = oerrno;
  80                 return (-1);
  81         }
  82
  83         if (!nochdir)
  84                 (void)chdir("/");
  85
  86         if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
  87                 (void)_dup2(fd, STDIN_FILENO);
  88                 (void)_dup2(fd, STDOUT_FILENO);
  89                 (void)_dup2(fd, STDERR_FILENO);
  90                 if (fd > 2)
  91                         (void)_close(fd);
  92         }
  93         return (0);
  94 }